Nissan M9R

Overview

Manufacturer Nissan and Renault

Also called 2.0 dCi

Production 2006-present

Layout

Configuration Inline-four

 2.0 L (1995 cc)
Displacement
 2.0 L (1997 cc) (Gen 5)

Cylinder bore  84 mm (3.31 in)

 85 mm (3.35 in) (Gen 5)

Piston stroke  88 mm (3.46 in) (Gen 5)

 90 mm (3.54 in)

Block material Cast iron

Head material Aluminium alloy

Valvetrain DOHC 4 valves per cylinder

Compression ratio 15.6:1

16.0:1

Combustion
 Turbocharger Yes

Fuel system Common rail Direct Injection

Fuel type Diesel

Cooling system Water-cooled

Output

Power output 130–200 PS (96–147 kW; 130–200 hp)

Torque output 320–400 N⋅m (240–300 lb⋅ft)

Chronology

Predecessor Renault F-Type engine

Successor Renault R-Type engine

2.0-liter VTEC®
A turbocharged and intercooled 2.0-liter VTEC® engine powers the 2021 Honda
Civic Type R and makes 306 horsepower and 295 pound-feet of torque. The power-
packed engine is wrapped in an eye-catching red cover for a sporty look even under the
hood.Mar 31, 2021

What kind of engine does a Honda Civic have?

Engine, Transmission, and Performance

Base models come standard with a 158-hp 2.0-liter four-cylinder while the upgrade
engine continues to be a turbocharged 1.5-liter four-cylinder that now makes 180
horsepower. The new Civic is offered solely with front-wheel-drive car.

Honda Accord Features

The standard engine is a 1.5-liter VTEC® Turbocharged 4-cylinder which produces 192

horsepower and 192 lb-ft of torque. Craving more power? The optional 2.0-liter turbo cranks out
252 horsepower along with 278 lb-ft of torque for instantaneous response.

1999 Honda HR-V 1.6 (UK)

 Overview

Production 1998–2006

Assembly Japan: Suzuka, Mie

Body and chassis

Body style 3-door SUV (GH1 & GH2)

5-door SUV (GH3 & GH4)

Related Honda Logo

Honda Capa

Powertrain

 Petrol:
Engine
 1.6 L D16W1 I4

 1.6 L D16W5 VTEC I4

Honda Vezel Hybrid engine

The Vezel Hybrid is powered by a 1.5 l i-VTEC and an electric motor. With 112 kW
(150 bhp) and 155 Nm of torque, the compact body is pushed with ease. This effortless
nature of the powertrain and a very smooth and fast dual-clutch gearbox translate to the
amazing fuel efficiency of 24.2 km/l.

Honda D16W1 type 1.6-litre SOHC or an all-wheel drive SOHC VTEC Honda D16W5 type engine.

A continuously variable transmission was optional.

Honda Vezel

Engine Type i-DTEC Diesel Engine

Displacement (cc) 1498

Max Power 98.6bhp@3600rpm

Max Torque 200Nm@1750rpm

Tips for Honda Vezel Hybrid Maintenance, Other Hybrid I-DCD Model apply
Vezel/Shuttle/Freed/Fit..

 Dual Clutch Actuator fluid flush and change @ every 20,000 km.
 Transmission fluid DW-1 @ every 30,000 km.
 Brake System fluid flush and change @ every 2 years or 60,000 km.
 Does the Honda CR-V have a V6 engine?
 The Honda CR-V does not have the option for a V6 engine in the current
models and there has never been a model produced that had a V6 as standard
or available as an option. The current model comes equipped with a 1.5 L
4Cylinder engine that is able to produce 190 hp.

What are the different Honda CR-V models?

The 2021 Honda CR-V comes in four trims: LX, EX, EX-L, and Touring. All models come
standard with a turbocharged four-cylinder engine, a continuously variable automatic
transmission (CVT), and front-wheel drive. All-wheel drive is optional in every trim for

Is Honda CR-V v4 or v6?

The engine in the 2020 Honda CR-V is a 1.5L inline 4-cylinder turbo. Coupled with
this engine is a continuously variable transmission (CVT). Drivers can take advantage of
a maximum of 190 horsepower at 5,600 RPM

Overall Reliability Rating

The Toyota RAV4 Reliability Rating is 4.0 out of 5.0, which ranks it 3rd out of 26 for compact
SUVs. ... The Honda CR-V Reliability Rating is 4.5 out of 5.0, which ranks it 2nd out of 26 for
compact SUVs.

Honda CR-V Specifications

Engine and Transmission

Engine Type i-DTEC Diesel Engine

Displacement (cc) 1597

Max Power 118.3bhp@4000rpm

Max Torque 300NM@2000rpm

Honda CR-V Specifications

Engine and Transmission

Engine Type i-VTEC Petrol Engine

Displacement (cc) 2354

Max Power 187.4bhp@7000rpm

Max Torque 226Nm@4400rpm

Engine Type SOHC i-VTEC BS6 Petrol Engine

Displacement (cc) 1997

Max Power 151.89bhp@6500rpm

Max Torque 189NM@4300rpm

Engine Type i-VTEC Petrol Engine

Displacement (cc) 1997

Max Power 151.89bhp@6500rpm

Engine Type SOHC i-VTEC BS6 Petrol Engine

Displacement (cc) 1997

Max Power 151.89bhp@6500rpm

The only available engine for the HR-V is a 1.8-liter naturally aspirated four-banger that
develops 141 hp and 127 lb-ft of torque. That grunt is routed via a CVT automatic for standard
FWD or available AWD. Front drivers are rated at 28/34 mpg city/highway, and those with four
driven wheels return 27/31 mpg.

Is Honda HRV 4 or 6 cylinder?

Honda makes the 2021 HR-V in four trim levels: LX, Sport, EX, and EX-L. All trims have
a four-cylinder engine and a continuously variable automatic transmission (CVT).
Front-wheel drive is standard; all-wheel drive is available.

i-VTEC I4
It is powered by a 1.8-litre SOHC i-VTEC I4 engine mated either to a CVT transmission
similar to the Civic or a 6-speed manual transmission (FWD only). Fuel economy for
front-wheel drive (FWD) automatic models is rated at 28/35/31 mpg
(city/highway/combined) or 27/32/29 mpg for all-wheel drive (AWD) models.

Does Sonata come in V6?

Hyundai also offered a 2.7-liter V6 engine and paired it with a four-speed automatic
transmission. ... The sixth-generation Hyundai Sonata was produced from the 2011 to
2014 model year.
Hyundai Sonata Specifications

Engine and Transmission

Engine Type GDi Petrol Engine

Displacement (cc) 2359

Max Power 198.25bhp@6300rpm

Max Torque 250Nm@4250rpm

Hyundai Tucson Specifications

Engine and Transmission

Engine Type R 2.0 I Diesel (BS6)

Displacement (cc) 1995

Max Power 182.46bhp@4000rpm

Hyundai Tucson Specifications

Engine and Transmission

Engine Type R 2.0 I Diesel (BS6)

Displacement (cc) 1995

Max Power 182.46bhp@4000rpm

Hyundai Tucson Specifications

Engine and Transmission

Engine Type Nu 2.0 I Petrol (BS6)

Displacement (cc) 1999

Max Power 149.92bhp@6200rpm

Hyundai Elantra Specifications

Engine and Transmission

Engine Type Nu 2.0 MPi Petrol Engine

Displacement (cc) 1999

Max Power 149.92bhp@6200rpm

Max Torque 192.2Nm@4000rpm

No. of cylinder 4

Valves Per Cylinder 4

Valve Configuration DOHC

Fuel Supply System MPFI

Hyundai Elantra Specifications

Engine and Transmission

Engine Type 1.5 L U2 diesel

Displacement (cc) 1493

Max Power 113.42bhp@4000rpm

Max Torque 250nm@1500-2750rpm

No. of cylinder 4

Hyundai Elantra Specifications

Engine and Transmission

Engine Type Nu 2.0 MPi Petrol Engine

Displacement (cc) 1999

Max Power 149.92bhp@6200rpm

Max Torque 192.2Nm@4000rpm

Mitsubishi
MITSUBISHI Lancer Ralliart 2.0 MIVEC Turbo 6AT (240 HP)

  MITSUBISHI Lancer 1.5 MIVEC 5MT (109 HP)

  MITSUBISHI Lancer 1.6 MIVEC 5MT (117 HP)
  MITSUBISHI Lancer 1.8 MIVEC 5MT (143 HP)
  MITSUBISHI Lancer 1.8 MIVEC CVT (143 HP)
  MITSUBISHI Lancer 2.0 MIVEC 5MT (152 HP)
  MITSUBISHI Lancer 2.4 GTS 5MT (168 HP)

DIESEL ENGINES:
   MITSUBISHI Lancer 1.8 DI-D 6MT (116 HP)
  MITSUBISHI Lancer 2.0 DI-D 6MT (140 HP)
Outlander

2.4L MIVEC 4-CYLINDER

The first three trim levels of the Mitsubishi Outlander run on a sporty 2.4L MIVEC 4-cylinder engine
that gets up to 166 horsepower and 162 lb-ft of torque. This Single Over Head Camshaft (SOHC)
design features 16 valves and delivers a compression ratio of 10.5.

Mitsubishi Xpander (NC1W)

Powertrain

Engine 1.5 L 4A91 MIVEC I4 (petrol)

Power output 77 kW (103 hp; 105 PS)

Transmission 5-speed manual 4-speed automatic

Mitsubishi Xpander (NC1W)

 Powertrain

Engine 1.5 L 4A91 MIVEC I4 (petrol)

Power output 77 kW (103 hp; 105 PS)

Mitsubishi Xpander (NC1W)PowertrainEngine1.5 L 4A91 MIVEC I4 (petrol)Power output77 kW (103 hp;
105 PS)Transmission5-speed manual 4-speed automatic

Fuel System

Working of EFI(electronic fuel

injection system)
Saptarshi Chakraborty

Sep 16, 2017·1 min read

The EFI system consists of 2 main compartments Low pressure

and High Pressure , the low pressure part consists of fuel tank,fuel
pump,heater & cooler,fuel filter whilst the high pressure part
consists of fuel injector,fuel injector nozzle,high pressure pump ,
fuel accumulator

here in this diagram we can see all the various parts of the system .
 1. The fuel starts moving from the fuel tank because of the
pump working to suck in the fuel from the fuel tank

2. After that the fuel travels through the filter , which filters
out the unwanted materials from the liquid .

3. after that it travels to the injectors , giving fuel to the

combustion chamber

4. we can see there is an accumulator present in-between the fuel

filter and fuel pump , henceforth the fuel travels to the distributor

5. from there it goes through the inlet pipe and then the inlet
manifold mixing with the air

INJECTION SYSTEM: COMPONENTS, TYPES AND WORKING

PRINCIPLES
06 Jul 2019 By INGENIERIA Y MECANICA AUTOMOTRIZ
“ Fuel injector is an electronically controlled mechanical device that is responsible for spraying
(injecting) the right amount of fuel into the engine so that a suitable air/fuel mixture is created for
optimal combustion.”

The technology was created in the early 20th century and implemented on diesel engines first. By
the final third of the 20th century, it had also become popular among regular gasoline engines.

The electronic control unit (ECU at engine management system) determines the precise amount and
specific timing of required gasoline (petrol) dose for every cycle, by collecting information from
various engine sensors. So, the ECU sends a command electrical signal of the correct duration and
timing to the fuel injector coil. In that way opens the injector and allows petrol to pass through it into
the engine.

The one terminal of the injector coil is directly supplied by 12 volts which are controlled by the ECU,
and the other terminal of the injector coil is open. When ECU determined the exact amount of fuel
and when to inject it, activates the appropriate injector by switching the other terminal to the ground
(mass, i.e. negative pole).
COMPONENTS

The objectives of the fuel injection system are to meter, atomize and distribute the fuel throughout
the air mass in the cylinder. At the same time, it must maintain the required air-fuel ratio as per the
load and speed demand on the engine.

* Pumping elements:

To move the fuel from the fuel tank to the cylinder.

* Metering elements:

To measure the supply of the fuel at the rate demanded by speed and load conditioning on the
engine

* Metering control:

To adjust the rate of the metering elements for change in load and speed of the engine.

* Mixture control:

To adjust the ratio of the fuel and air as demanded by the load and speed.

* Distributing elements:

To divide the metered fuel equally among the cylinder.

* Timing control:
To fix the start and stop of the fuel-air mixing process.

TYPES OF FUEL INJECTORS

1. Top-Feed – Fuel enters from the in the top and exits the bottom.

2. Side-Feed – Fuel enters on the side on the injector fitting inside the fuel rail.

3. Throttle Body Injectors – (TBI) Located directly in the throttle body.

TYPES OF FUEL INJECTION SYSTEMS

1. Single-Point OR Throttle Body Fuel Injection

Also referred to as a single port, this was the earliest type of fuel injection to hit the market. All
vehicles have an air intake manifold where clean air first enters the engine. TBFI works by adding
the correct amount of fuel to the air before it is distributed to the individual cylinders. The advantage
of TBFI is that it’s inexpensive and easy to maintain. If you ever have an issue with your injector,
you’ve only got one to replace. Additionally, since this injector has a fairly high flow rate, it’s not as
easy to clog up.
Technically, throttle body systems are very robust and require less maintenance. That being said,
throttle body injection is rarely used today. The vehicles that still use it are old enough that
maintenance will be more of an issue than it would with a newer, lower mileage car.

Another disadvantage to TBFI is the fact that it’s inaccurate. If you let off the accelerator, there will
still be a lot of fuel in the air mixture that is being sent to your cylinders. This can result in a slight lag
before you decelerate, or in some vehicles, it can result in unburned fuel being sent out through the
exhaust. This means that TBFI systems are not nearly as fuel efficient as modern systems.

2. Multiport Injection

Multiport injection simply moved the injectors further down towards the cylinders. Clean air enters
the primary manifold and is directed out towards each cylinder. The injector is located at the end of
this port, right before it’s sucked through the valve and into your cylinder.

The advantage of this system is that fuel is distributed more accurately, with each cylinder receiving
its own spray of fuel. Each injector is smaller and more accurate, offering an improvement in fuel
economy. The downside is that all injectors spray at the same time, while the cylinders fire one after
the other. This means that you may have leftover fuel in between intake periods, or you may have a
cylinder fire before the injector has had a chance to deliver additional fuel.

Multiport systems work great when you are traveling at a consistent speed. But when you are quickly
accelerating or removing your foot from the throttle, this design reduces either fuel economy or
performance.

3. Sequential Injection

Sequential fuel delivery systems are very similar to multiport systems. That being said, there is one
key difference. Sequential fuel delivery is times. Instead of all injectors firing at the same time, they
deliver fuel one after the other. The timing is matched to your cylinders, allowing the engine to mix
the fuel right before the valve opens to suck it in. This design allows for improved fuel economy and
performance.

Because fuel only remains in the port for a short amount of time, sequential injectors tend to last
longer and remain cleaner than other systems. Because of these advantages, sequential systems
are the most common type of fuel injection in vehicles today.

the one small downside to this platform is that it leaves less room for error. The fuel/air mixture is
sucked into the cylinder only moments after the injector opens. If it is dirty, clogged, or unresponsive,
your engine will be starved of fuel. Injectors need to be kept at their peak performance, or your
vehicle will start to run rough.

4. Direct Injection

If you’ve started to notice the pattern, you can probably guess what direct injection is. In this system,
fuel is squirted right into the cylinder, bypassing the air intake altogether. Premium automobile
manufacturers like Audi and BMW would have you believe that direct injection is the latest and
greatest. With regards to the performance of gasoline vehicles, they’re absolutely right! But this
technology is far from new. It’s been used in aircraft engines since the second world war, and diesel
vehicles are almost all direct injection because the fuel is so much thicker and heavier.
In diesel engines, direct injection is very robust. Fuel delivery can take a lot of abuse, and
maintenance issues are kept to a minimum.

With gasoline engines, direct injection is found almost exclusively in performance vehicles. Because
these vehicles operate with very precise parameters, it’s especially important to maintain your fuel
delivery system. Although the car will continue to run for a long time when neglected, the
performance will quickly decline.

METHODS OF FUEL INJECTION

There are two methods of fuel injection in the compression ignition system

1. Air blast injection

2. Air less or solid injection

1. Air blast injection

This method was originally used in large stationary and marine engines. But now it is obsolete. In
this method, the air is first compressed to very high pressure. A blast of this air is then injected
carrying the fuel along with it into the cylinders. The rate of fuel injection is controlled by varying the
pressure of the air. The high-pressure air requires a multi-stage compressor so as to keep the air
bottles charged. The fuel ignites by the high temperature of the air caused by the high compression.
The compressor consumes about 10% of the power developed by the engine, decreasing the net
output of the engine.
2. Airless or solid injector

In this method, the fuel under high pressure is directly injected into the combustion chamber. It burns
due to the heat of compression of the air. This method requires a fuel pump to deliver the fuel at high
pressure around 300kg/cm^2. This method is used for all types of small and big diesel engines. It
can be divided into two systems

1. Individual pump system: in this system each cylinder has its own individual high-pressure pump
and a measuring unit.

2. Common rail system: in this system the fuel is pumped by a multi-cylinder pump into a common
rail, the pressure in the rail is controlled by a relief valve. A measured quantity of fuel is supplied to
each cylinder from the common rail.

This is all about the fuel injection system. If you have any query regarding this article, ask by
commenting. If you like this article, don’t forget to share it on social networks. Subscribe our website
for more informative articles. Thanks for reading it.

WORKING PRINCIPLES

The injectors are controlled by the Engine Control Unit (ECU). First, the ECU obtains information
about the engine conditions and requirements using different internal sensors. Once the state and
requirements of the engine have been determined, the fuel is drawn from the fuel tank, transported
through the fuel lines and then pressurized with fuel pumps. Proper pressure is checked by a fuel
pressure regulator. In many cases, the fuel is also divided using a fuel rail in order to supply the
different cylinders of the engine. Finally, the injectors are ordered to inject the necessary fuel for the
combustion.

The exact fuel/air mixture required depends on the engine, the fuel used and the current
requirements of the engine (power, fuel economy, exhaust emission levels, etc.)

(Automotive World)
 FUEL SYSTEM

You already know about internal combustion engines, which can be working on a

fuel (gas or diesel), that needs to the engine work. Fuel must supply to the
engine cylinders in timely manner, so the fuel system do this task.  This article
is about types fuel systems, fuel system construction and how a fuel system
works. Figures and diagrams will help you understand fuel system
construction.
The purpose of car fuel system
Car fuel system`s purpose is supply fuel from fuel tank to the engine cylinder.
Also this system provides the fuel storage and cleaning before admission to
the cylinder.
The base fuel system has next main elements:
1. Fuel tank – it is a fuel storage reservoir. The fuel tank of modern
cars is a difficult system, which includes next elements: reservoir,
fuel neck, fuel gauge, fuel pump, and others;
2. Fuel Pipeline system – these is pipelines that provide fuel supply
to other fuel elements;
3. Fuel pump – is a device which pumping the fuel from tank to the
engine; Fuel pump of modern injection systems creates enough
high pressure. Electrical fuel pumps are common using on the
modern car. Diesel engine pumps can be two types of: low and
high pressure. Typically high pressure pump are used on the diesel
engine.
4. Fuel filter (or filters). There are two types of fuel filters, like coarse
fuel filter and fine fuel filter; The purpose of filters are cleaning of
fuel from different types of dirty, dusty and so on.
5. Fuel injection device or Carburetor. It is device in which supply fuel
and air to creating air-fuel mixture.  
Fuel injection device – are nozzles of the diesel or engine injector.But the fuel
nozzles are located into the head cylinder in diesel motors and direct fuel
injector motors. And in injector motors fuel nozzles are into intake manifold.
Fuel injection system construction. For the engine to run smoothly and
efficiently, it needs to be provided with the right quantity of fuel/air mixture
according to its demands.
A fuel injection system consists of:
1. Fuel tank
2. Fuel pump
3. Fuel line
4. Fuel filter
5. Fuel accumulator
6. Fuel distributor
7. Inlet tract
8. Inlet manifold
9. Injectors

Common Rail Injection System

Pressure Control
Hannu Jääskeläinen, Alessandro Ferrari
This is a preview of the paper, limited to some initial content. Full access requires DieselNet subscription.
Please log in to view the complete version of this paper.

Abstract: There are several approaches to control the pressure in the common rail. One early approach
method was to supply more fuel than is needed to the common rail and use a pressure control valve to
spill the excess fuel back to the fuel tank. A more preferred approach is to meter the fuel at the high
pressure pump in order to minimize the amount of fuel pressurized to the rail pressure. A variety of fuel
metering can be used for the later. Some practical common rail implementations utilize both approaches
with the control strategy depending on the engine operating conditions.

 Introduction

 Pressure Control Valve

 Pump Metering

 Practical Rail Pressure Control

Introduction
Production common rail fuel systems are equipped with a closed-loop high pressure control-
system that stabilizes the rail pressure within a relatively small margin to the nominal value
specified by the electronic control unit for a given engine operating condition. The pump
maintains the rail pressure by continuously delivering fuel to the common rail. This pressure is
monitored by a pressure sensor and the difference between the nominal rail pressure value and
the measured one is the input signal for the controller. In control terminology, the rail pressure is
the system output while the position of the actuator used to control the rail pressure is the system
input.
There are a number of approaches to control the pressure in the common rail. One way is to
supply more fuel than is needed to the common rail and use a high pressure regulator—
commonly referred to as a pressure control valve—in the high-pressure circuit to spill the excess
fuel back to the fuel tank. In this approach, the pressure control valve position is the control
system input. While this approach was used exclusively in some early fuel injection systems
such as those with Bosch CP1 pumps (Figure 1 and Figure 2), poor efficiency and an excessively
high fuel return temperatures can result.
Another approach is to meter the fuel at the high pressure pump to ensure that only the amount of
fuel required by the injectors is supplied to the common rail. A number of pump metering
approaches are possible. One common approach is to meter the fuel drawn into the pump (inlet
metering) with some type of inlet metering valve (IMV)—sometimes also referred to simply as a
fuel metering valve (FMV). Another approach is to allow the pump to draw in an uncontrolled
amount of fuel and meter the pump’s discharge flow (outlet metering) with a valve such as an
outlet metering valve (OMV). Another means is to vary the effective displacement of the high
pressure pump. By carefully controlling the amount of fuel entering the pump and avoiding
compression of excess fuel to high pressure, the fuel injection system hydraulic efficiency can be
improved and generation of excessively high fuel temperatures can be avoided. It should be
noted, however, that metering the fuel at the injection pump may not avoid the need for a high
pressure regulator. A pressure regulator can still be used to provide some trimming of the rail
pressure.

Pressure Control Valve

A pressure control valve (PCV) for controlling rail pressure can be located at one rail extremity
(pump-external PCV), Figure 1, or at the pump outlet (pump-integrated PCV), Figure 2. The
pump-external PCV leads to lower pump manufacturing costs but the proximity of the regulator
to the injectors can introduce additional disturbances in injector dynamics. In the pump-
integrated PCV solution, the fuel throttled by the control valve joins the leakage flow from the
pumping chambers as well as the fuel flowing in the pump’s cooling and lubrication circuits.
This combined flow is discharged from the pump to return to the fuel tank.

Figure 1. Common rail diesel fuel injection system with pressure control valve located on the rail
(Source: Bosch)
 Figure 2. Bosch CP1
pump with integrated pressure control valve

What is CRI injection?

Cuttings Re-Injection (CRI) involves injection of waste from drilling operations (slop
and drill cuttings) into a suitable deep geologic formation. ... This process is
considered an environmental friendly and cost-effective disposal method during drilling
operations, especially with offshore E&P operations.
How does a diesel injection system work?
The fuel injection system lies at the very heart of the diesel engine. By pressurising and
injecting the fuel, the system forces it into air that has been compressed to high
pressure in the combustion chamber. ... high-pressure pipe - sends fuel to the
injection nozzle. injection nozzle - injects the fuel into the cylinder.

Do electric fuel pumps run continuously?

The fuel pump runs continuously once the engine starts, and continues to run as
long as the engine is running and the ignition key is on. The pump may run at a
constant speed, or it may operate at a variable speed depending on engine load and
speed.

Common rail direct fuel injection is a direct fuel injection system built around a high-pressure
(over 2,000 bar or 200 MPa or 29,000 psi) fuel rail feeding solenoid valves, as opposed to a
low-pressure fuel pump feeding unit injectors (or pump nozzles).

What is CRDi fuel system?

CRDi stands for Common rail direct injection which means the direct injection of fuel
into the cylinder of a diesel engine through a single common line called common rail
which is connected to fuel injectors.
What is the most common fuel injection system?
As technology advances, direct injection engines may become easier to manufacture,
but, for now, sequential multi-port injection remains the most common fuel injection
system in cars today. It provides the right mix of efficiency and affordability for most
applications.

The fuel injection types used in newer cars include four basic types:
 Single-point or throttle body injection.
 Port or multipoint fuel injection.
 Sequential fuel injection.
 Direct injection.
Single-point injection uses one injector in a throttle body mounted similarly to a carburetor on
an intake manifold. As in a carbureted induction system, the fuel is mixed with the air before the
inlet of the intake manifold.

Throttle Body Injection:

Carburetors were first replaced by throttle body injection (also know as single point or central fuel
injection). This system can use a single or multiple electrically controlled fuel- injectors located above the
throttle body, the same location as was used by carburetors. For this reason, these were almost a bolt-in
replacement for the carburetor allowing throttle body injection to be simple explained as being a computer
controlled carburetor. Automakers didn't have to make any drastic changes to their engine designs and so
components such as the air cleaner, intake manifold, and fuel line routing could all be reused. And so the
justification for  single point injection was the low cost. These systems were not around very long only
acting as a transition from carburetors to multi-port fuel injection.

Home - Blog - Automobile Engineering

Electronic fuel injection System : Parts ,Types, Working ,

Advantages
Written by Sachin Thorat  in Automobile Engineering

Table of Contents
 EFI System – Electronic Fuel Injection System : 
o Difference Between Electronic Fuel Injection and Carbureted fuel system
o Types Of Electronic Fuel injection System:
o Single point injection System:
o Electronic Fuel Injector (Unit Injector):
o Throttle body injection (TBI) system – Working of electronic fuel injection
system 
o Testing of Electronic Fuel Injector :
 Ohm-meter test for electronic fuel injector. 
 Sound test for testing electronic fuel injector
o Advantage of an electronic fuel injection system: 
o Disadvantages of Electronic Fuel Injection System :
EFI System – Electronic Fuel Injection System : 
In Electronic Fuel Injection System, carburetors were replaced with throttle body fuel
injection systems, also known as single point or central fuel injection systems. That
incorporated electrically controlled fuel-injector valves into the throttle body. Those
were almost a bolt-in replacement for the carburetor, so the automakers didn’t have to
make any drastic changes to their engine designs.

Difference Between Electronic Fuel Injection

and Carbureted fuel system
Sr
Electronic Fuel Injection Carbureted fuel system
no.

1. Uniform distribution of charge. Mal-distribution of charge.

2. Improvement in volumetric efficiency due to less resistance Due to resistance in the intake manifold, volum
in the intake manifold. efficiency is lower

3. Accurate metering of charge Inaccurate metering of charge.

4. The formation of ice on the throttle plate is eliminated. Carburetor Icing may take place

5. Atomization of fuel is independent of cranking speed Fuel atomization depends upon the velocity of
therefore cranking is easier. venture.

6. Better atomization and vaporization will make the engine less Less atomization and vaporization will make th
knock prone. more knock prone.

7. Less volatile fuel can be used. Fuel needs to be more volatile

8. Fuel being injected into or close to the cylinder. Fuel injection is take place inside the manifold.

Types Of Electronic Fuel injection System:

 Single-Point or Throttle Body Injection
  Port or Multi-Point Fuel Injection
 Sequential Fuel Injection
 Direct Injection

Single point injection System:

Definition:

A type of electronic fuel injection system that uses a single injector or pair of injectors
mounted in a centrally located throttle body. The throttle unit resembles a carburetor
except that there is no fuel bowl float or metering jets. Fuel is sprayed directly into the
throttle bore(s) by the injector(s).

With single-point injection it is possible to achieve a lambda regulated exhaust emission

control using only a few components.

Sensors

 Inductive pickup – position of the crankshaft and speed of the engine;

 Lambda probe;
 Temperature sensors for cooling water system and air intake system; Throttle
potentiometer;

Actuators

 Fuel injector; – The fuel injector acts as the fuel dispensing nozzle. It injects liquid
fuel directly into the engine’s air stream. The injection is controlled by the ECU. It
determines the amount of fuel to injected and in some system if the engine is cold,
turns on an “extra” injector which only works while the system is cold. This injector
only works for a short period of time determined by the ECU.
 Throttle plate control- This is system is used to control the minimum airflow during
idle speed. It actuates directly in to the Throttle plate, this is normally done by a
small electric motor applied directly to the throttle plate.

Electronic Fuel Injector (Unit Injector):

 A vacuum-powered fuel pressure regulator at the end of the fuel rail ensures that the
fuel pressure in the rail remains constant relative to the intake pressure. For a
gasoline engine, fuel pressure is usually on the order of 35-50 psi. Fuel injectors
connect to the rail, but their valves remain closed until the ECU decides to send fuel
into the cylinders.
 Usually, the injectors have two pins. One pin is connected to the battery through the
ignition relay and the other pin goes to the ECU.
  The ECU sends a pulsing ground to the injector, which closes the circuit, providing
the injectors solenoid with current. The magnet on top of the plunger is attracted to
the solenoids magnetic field, opening the valve. Since there is a high pressure in the
rail, opening the
valve sends fuel at a high velocity through the injectors spray tip.
 The duration that the valve is open and consequently the amount of fuel sent into
the cylinder depends on the pulse width (i.e. how long the ECU sends the ground
signal to the injector).
 When the plunger rises, it opens a valve and the injector sends fuel through the
spray tip and into either the intake manifold, just upstream of the intake valve, or
directly into the cylinder.

electronic fuel injector diagram

Throttle body injection (TBI) system – Working

of electronic fuel injection system 
The throttle body injection (TBI) system uses one or two injector valves mounted in a
throttle body assembly. The injectors spray fuel into the top of the throttle body air
horn The TBI fuel spray mixes with the air flowing through the air horn. The mixture is
then pulled into the engine by intake manifold vacuum. The throttle body injection
assembly typically consists of the following: throttle body housing, fuel injectors, fuel
pressure regulator, throttle positioner, throttle position sensor, and throttle plates.

Throttle Body Injection is an electronically controlled injection system in which an

electronic fuel injector injects the fuel intermittently in to the intake manifold at a
central point ahead of the throttle valve. The central- injection unit operates at low
pressure (0.7 to 1 bar) so; an inexpensive hydrodynamic electric fuel pump can be used
(generally in the form an in-tank unit). The injector is flushed continuously by the fuel
flowing through it in order to prevent the formation of air bubbles. The injector is a
solenoid – controlled valve. The central injection unit uses the throttle valve to meter
the intake air while injecting the fuel intermittently above the throttle valve. The intake
manifold then
distributes the fuel to the individual cylinders. Various sensors monitor all important
engine-operating data, which are then used to calculate the triggering signals for the
injectors and other system actuators.

th
rottle body injection system

Testing of Electronic Fuel Injector :

Ohm-meter test for electronic fuel injector.  
Following are the steps of the Ohmmeter test for electronic fuel injector:
• An ohmmeter is connected across the injector terminals to check the injector windings
after the injector wires are disconnected.
• If the ohmmeter reading is infinite, the injector winding is open.
• An ohmmeter reading below the specified value indicates that the injector winding is
shorted.
• A satisfied injector winding should have resistance between 0.3 to 0.4 ohms.
• Replace the injector if the results do not have the resistance as specified by the
manufacturer.

electronic fuel injector testing

Sound test for testing electronic fuel injector

Procedure for sound test for testing electronic fuel injector:

The use of auto fuel injectors is a sophisticated way to provide the right fuel and air mix
to an engine for a vehicle. The small cylindrical fuel injectors play a specific role in a
larger fuel intake system, along with other elements like the fuel pump and the fuel
tank. Over time, fuel injectors may need to be maintained or checked for proper
functioning.

1) The electronic fuel injection system relies on electronic signals that control how
these items operate
2) Along with checking a fuel injector electronically, you can listen for certain kinds
of sounds that will tell you when a fuel injector might not be working correctly.
3) A clunking sound or similar warning sound may show that the fuel injector is
not functioning the way it should.
4) If the injector electrical leads are difficult to access, an injector power balance test
is hard to perform. As an alternative, start the engine and use a technician stethoscope
to listen for correct injector operation.
5) A good injector makes a rhythmic clicking sound as the solenoid is energized and de-
energized several times each second.
6) If clunk- clunk instead of steady click-click is heard, chances are the problem
injector has been found.
7) Cleaning or replacement is in order.
8) If an injector does not produce any clicking noise, the injector, connecting wires, or
PCM may be defective.
9) When the injector clicking noise is erratic, the injector plunger may be sticking.
10) If there is no injector clicking noise, proceed with the injector resistance test and
light to locate the cause of the problem.
11) If a stethoscope is not handy, use a thin steel rod, wooden dowel, or fingers to feel
for a steady on/off pulsing of the injector solenoid.

Advantage of an electronic fuel injection

system: 
1. Improved power output.
2. Better fuel efficiency over a wide range of engine speeds.
3. Quick warm-up of engine.
4. Reduced engine emission that meets strict emission norms.
5. Better throttle response of the engine.
6. Better pick- up (acceleration).
7. Compact design of the fuel supply system.
8. Modular design.
9. Engine performance is maintained under various loads and atmospheric pressures
(altitude).
10. Engine need not be tuned from time to time as in the case of a carbureted engine
fuel supply system.
11. Engine idle speed is controlled by a microprocessor and so precisely controlled.
12. The vapor lock problem does not occur, as EFI system uses an electric fuel feed
pump. The pump maintains sufficient pressure in the fuel line to avoid vapor lock in hot
weather.
13. Improved atomization. Fuel is forced into the intake manifold under pressure that
helps break fuel droplets into a fine mist.
14. Better fuel distribution. Equal flow of fuel vapors into each cylinder.
15. Smoother idle. Lean fuel mixture can be used without rough idle because of better
fuel distribution and low-speed atomization.
16. Lower emissions. Lean efficient air-fuel mixture reduces exhaust pollution.
17. Better cold-weather drivability. Injection provides better control of mixture
enrichment than a carburetor.
18. Increased engine power. Precise metering of fuel to each cylinder and increased
airflow can result in more horsepower output.
19. Fewer parts. Simpler, late model, electronic fuel injection system have fewer parts
than modern computer-controlled carburetors

Disadvantages 

EFi Vs MPFi Vs GDi: How Electronic Fuel Injection

Technology Works?
By: CarBikeTech
On October 3,2018 | 4 Minutes Read
EFi, MPFi, GDi -
EFi stands for Electronic Fuel injection (EFi) whereas MPFi or MPi stands for Multi-Point
Fuel injection and GDi stands for Gasoline Direct Injection. All these are the types of
fuel injection systems which the gasoline or petrol fuel engines mainly use. All these
terms refer to the newer generation Petrol Injection systems.

Earlier, older engines used simple Fuel Injection (Fi) which replaced the carburetor to
overcome some of its shortcomings. The carburetor, being a mechanical device, was
just not fully capable of controlling an accurate air-fuel ratio to meet the growing
demands for better emission control.

Hence, it was replaced with first generation Fuel Injection technology. In this method,
the petrol fuel is atomized by forcing it thru’ an injector as opposed to its suction created
in a venturi tube in a carburetor which lifts the petrol thru’ its orifices. Thus, there is a
fundamental difference between the earlier generation carburetor & newer generation
Fuel Injection (EFi) system.

Earlier, the first generation Fuel Injection featured a simple design which consisted of
an injector and a mechanical fuel pump. Basically, the fuel pump provided sufficient
pressure to open the injector hydro-mechanically. Later, this system was upgraded to
include electrically operated Injector by an ECU which is the first generation Electronic
Fuel Injection systems or EFi.

Throttle Body Injection (TBI) -

Throttle Body Injection is also known as Central Fuel injection system. It consists of an
electrically controlled fuel injector placed above the butterfly valve (throttle) and
sprays fuel into the throttle body.
 1st
Generation EFi - Throttle Body Injection System - TBI

Single-Point Fuel Injection –

Single Point Fuel Injection is the second generation Fuel Injection system which used
electronically controlled Fuel Injection (EFi). Furthermore, it governed the injection
timing accurately with the help of an ECU, sensors, and actuators. It used a ‘common-
to-all-cylinders’ injector which supplied petrol in atomized form.

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 2n
d Generation EFi - Single Point Injection System - Manifold Injection

However, the engineers moved it from its earlier position in the throttle-body to the
intake manifold. Here, the petrol mixes with the incoming air. Then, the air-fuel mixture
(known as charge) goes to each cylinder. Hence, this system is also called the
“Manifold Injection” since the injection of petrol occurs inside the inlet manifold.

Multi-Point Fuel Injection (MPFi) –

Furthermore, the manufacturers developed the Manifold injection system to include

‘one-for-each-cylinder’ injector which provided four injectors to in a four-cylinder engine.
The engineers labeled this electronically controlled, superior technology as
the ‘Sequential fuel injection’ aka Multi-Port / Multi-Point Fuel Injection or in short the
MPFi / MPi.
 3rd
Generation EFi - Multi-Point Fuel Injection - MPFi

The MPFi uses separate injector for each cylinder to supply the correct quantity of fuel
via a 'fuel-rail' according to the 'Firing Order' or in a ‘particular sequence’. Also, MPFi
system provides further precision by varying the fuel quantity and injection timing by
governing each injector separately. It thereby improves the performance and controls
the emissions effectively.

This technology consists of the following parts:

1. Injectors
2. Fuel Pump
3. Fuel Rail
4. Fuel Pressure Sensor
5. Engine Control Unit
6. Fuel Pressure Regulator
7. Various Sensors - Crank/Cam Position Sensor, Manifold Pressure sensor, Oxygen
Sensor

#Gasoline Direct Injection (GDI) –

Gasoline Direct Injection (GDI) is also known as Petrol Direct Injection / Spark Ignited
Direct Injection (SIDI) / Fuel Stratified Injection (FSI) which is the latest EFi technology.
Additionally, it uses special injectors that spray the petrol at a very high pressure. Unlike
the MPFi system, this injector sprays the petrol directly into the combustion chamber
just like diesel engines.

4th
generation EFi - Gasoline Direct Injection - GDi

The sophisticated ‘Engine Management System’ (EMS) precisely controls the mixing of
air & fuel. The mixing of air and petrol occurs inside the combustion chamber rather
than in the inlet manifold. Thus, this method provides greater control over the
combustion process. In addition, it also provides multiple combustion modes which
include ultra-lean-burn air-fuel ratios. Nowadays, newer generation engines use GDI in
combination with a Turbocharger which improves engine performance.

Benefits of Fuel Injection in Petrol Engines are -

1. Smoother and more reliable engine response

2. Elimination of the choke and easier cold starting
3. Better engine operation even at extreme ambient temperatures
4. Smoother engine idle and running
5. Increased fuel efficiency
6. Reduced CO2 emissions
Opel Corsa B 1993–2000 Service and Repair Manual:
Single-point fuel injection system components (1.4 and 1.6
litre models) - removal and refitting
Opel Corsa B 1993–2000 Service and Repair Manual / Fuel and exhaust systems - fuel-injected models / Single-point fuel injection
system components (1.4 and 1.6 litre models) - removal and refitting

1. Disconnect the battery negative lead and proceed as described under the relevant subheading (see
illustration).

Single-point fuel injection system components and location on 1.4 litre model

1. Throttle valve injection housing

2. Fuel pump sensor
3. Filter
4. Fuel pressure regulator
5. Injection valve
6. Throttle valve (potentiometer)
7. Idle air stepper motor
8. Inlet manifold pressure sensor
9. Coolant temperature sensor
10. Road speed sensor
11. Octane number plug (95/91)
12. Unheated oxygen sensor
 13. Ignition distributor (Hall)
14. Engine telltale
15. ALDL plug
16. Wiring harness
17. Control unit
18. Three-way catalytic converter
19. Exhaust system
20. Heat shield
21. Tank filler neck
22. Damping control system
Throttle body/injector housing unit components

2. The following items can be removed from the throttle body/injector housing unit for inspection and where
necessary, renewal. If the unit is in position in the car, first remove the air cleaner unit to allow suitable access
to the appropriate component (see illustration).

Exploded view of the throttle body/injector housing assembly - 1.4 and 1.6 litre models

1. Air filter seal

2. Injection valve
3. Injection valve holder
4. Upper O-ring
 5. Lower O-ring
6. Upper housing
7. Seal
8. Fuel inlet connector
9. Fuel inlet seal
10. Fuel return connector
11. Fuel pressure regulator diaphragm
12. Fuel pressure regulator spring
13. Fuel pressure regulator spring seat
14. Fuel pressure regulator cover
15. Connecting cable grommet
16. Throttle body
17. Potentiometer (throttle valve)
18. Idle air stepper motor
19. O-ring
20. Idle adjustment screw
21. Idle adjustment screw spring
22. Cap
23. Vacuum connections flange
24. Vacuum connections flange seal
25. Injector housing- inlet manifold seal
Throttle valve potentiometer

3. Disconnect the wiring connector from the potentiometer, then undo the retaining screws and remove the
potentiometer from the throttle housing (see illustrations).

Detach the wiring connector from the throttle valve potentiometer

 Throttle valve potentiometer removal

4. Refitting is a reversal of the removal procedure. Ensure that the throttle valve is fully shut as the
potentiometer is fitted into position and that the pick-up is properly seated on the throttle spindle. Tighten the
retaining screws to the specified torque setting.

5. Reconnect the wiring plug and refit the air cleaner unit.

Injection valve

6. Disconnect the wiring plug. Undo the retaining screw then carefully lever the injection valve free using a
suitable screwdriver. Remove the injection valve together with its holder (see illustrations).

Disconnect the wiring connector . . .

 . . . undo the retaining screw . . .

. . . and remove the injector

7. Refit in the reverse order of removal.

Always renew the seal rings and as the injection unit is pressed into position, ensure that the wiring connector
is facing up (towards the retaining screw). If the retaining screw was fitted with a washer, discard the washer
and apply a suitable locking compound to the screw threads before screwing it into position.

Throttle body upper injector housing

8. Detach the wiring connector, undo the retaining screws and lift the upper injector housing clear of the main
body. Remove the seal.

9. Unscrew the union nuts and detach the fuel lines from the injector housing.

10. Refit in the reverse order of removal.

Remove the seal located between the upper housing and the main body. Where the retaining screws were fitted
with washers, discard the washers and coat the threads of the screws with a suitable locking compound.
Tighten the retaining screws to the specified torque to secure the upper body to the main body.

Idle air stepper motor

11. Detach the wiring connector, undo the retaining screws and withdraw the idle air stepper motor unit from
the injector unit housing (see illustrations).

Detach the wiring connector . . .

. . . undo the retaining screws . . .

 . . . and remove the idle air stepper motor

12. Refit in the reverse order of removal. To avoid damaging the injector housing as the motor unit is refitted,
press the cone in against its stop and check that the top of the cone to the mating flange face is within 28 mm
(see illustration).

Idle air stepper motor cone tip-toflange distance should be as specified

Throttle body/injector housing unit

13. Disconnect the wiring connectors from the throttle body/injector housing.

14. Disconnect the operating rod, then unscrew and remove the two retaining nuts from the studs and carefully
lift the throttle body/injector housing from the inlet manifold.

Remove the gasket and clean the mating surfaces.

15. Refit in the reverse order of removal, but be sure to fit a new gasket between the manifold and the throttle
body/injector unit.
Tighten the retaining nuts to the specified torque setting.

Pressure regulator

16. Prior to removal of the regulator unit, a new diaphragm must be obtained as this must be renewed
whenever the cover is removed.

Release the pressure in the fuel system.

17. Undo the four retaining screws and carefully withdraw the regulator unit cover, spring and diaphragm (see
illustrations).

Undo the retaining screws . . .

. . . and remove the pressure regulator cover, spring and diaphragm

18. Refit in the reverse order of removal.

Ensure that the new diaphragm and its seatings are clean. Note that no adjustment to the regulator unit is
necessary (or possible).
Inlet manifold pressure sensor

19. This unit is located on the engine side of the bulkhead. Disconnect the wiring connector and the vacuum
hose, then detach and remove the unit from the bulkhead.

20. Refit in the reverse order of removal, ensuring that the vacuum hose and wiring plug are securely
reconnected. Position the vacuum hose so that it progressively slopes down between the inlet manifold
pressure sensor and the throttle housing.

Control unit

21. Detach and remove the trim panel from the right-hand footwell to gain access to the control unit.

22. Disconnect the wiring multi-plug connectors, undo the retaining screw then release and remove the control
unit.

23. The control unit also contains a programmable memory (PROM) unit in which the engine/vehicle data and
calibration are stored. If this unit is known to be faulty it can be removed from the control unit and renewed
separately. If the control unit is at fault, the PROM unit should be removed from it, the control unit alone
renewed and the original PROM unit fitted to the new control unit.

24. To separate the PROM from the control unit, detach and withdraw the cover from the end of the control
unit, then press back the retaining clips, unplug and withdraw the PROM unit from the control unit. When
removed, no attempt must be made to open and/or tamper with the PROM unit. Ensure that its plug contacts
are clean and in good condition.

25. If renewing the control unit it is important that the part number/code sticker label is transferred to the new
unit.

26. Refit in the reverse order of the removal procedure. On completion, switch on the ignition and check for
satisfactory operation.

Coolant temperature sensor

27. Partially drain the cooling system to allow the temperature sensor to be removed without excessive coolant
loss.

28. Disconnect the multi-plug from the temperature sensor, then unscrew the sensor.

Note the position of the sealing ring.

29. Refitting is a reversal of the removal procedure, using a new sealing ring and tightening the sensor
securely.

Road speed sensor

30. Unclip the road speed sensor multi-plug, located near the base of the speedometer cable, and disconnect it.
Unscrew and detach the speedometer cable from the sensor.

31. Unscrew the road speed sensor from its gearbox location and remove it.

32. Refitting is the reverse to removal.

 Fuel injection system - testing and adjustment
Testing 1. If a fault appears in the fuel injection system first ensure that all the system wiring connectors are
securely connected and free of corrosion. Then ensure that the fault is not due t ...

Multi-point fuel injection system components (1.8 and 2.0 litre models) - removal and refitting
1.8 litre models Throttle valve switch 1. Disconnect the battery and proceed as described under the relevant
sub-heading. 2. Disconnect the wiring plug from the switch. 3. Remove the two mounting ...

See also:
What is port or multipoint fuel injection?
Multipoint fuel injection devotes a separate injector nozzle to each cylinder, right outside
its intake port, which is why the system is sometimes called port injection. Shooting the
fuel vapor this close to the intake port almost ensures that it will be drawn completely
into the cylinder.
What is the difference between throttle body injection and multi port injection?
Throttle body injection uses a single fuel injector to inject fuel right before the throttle
body. Multi port injection is the most common since the early/mid 90s. Each cylinder
gets its own fuel injector mounted in the intake manifold.

Understanding a multi-point fuel injection

system
November 8, 2020 Automobile Leave a comment

After the various articles published on this site on a fuel injection system in internal combustion engines,
here we are on the multi-point injection types. The multi-point injection is a system or technique in which
fuel is introduced into the cylinder of an internal combustion engine.

Today you’ll get to know the definition, functions, components, diagram, types, and working of a multipoint
injection system. you’ll also get to know its advantages and disadvantages.
Read more: Understanding the fuel injection system in automobile engines
Contents [hide]
 1 What is a multi-point injection system (MPFI)?
 2 Functions of multi-point fuel injection
 3 Components of a multi-point fuel injection
o
 3.0.1 Multi-point fuel injection diagram:
 4 Types of multi-point fuel injection system (MPFI)
 5 Working principle
o
 5.0.1 Watch the video to learn more about how a multi-point fuel injection
system works:
o 5.1 Join our Newsletter
 6 Advantages and disadvantages of a multi-point fuel injection (MPFI) system
o 6.1 Advantages:
o 6.2 Disadvantages:

What is a multi-point injection system (MPFI)?

A multi-point injection which is abbreviated as MPFI is a system that injects fuel into the intake ports just
upstream of each cylinder’s intake valve, rather than at a central point within an intake manifold.
Just as earlier mentioned, the MPFI is a system of injecting fuel into an internal combustion engine
through multi ports situated on the intake valve of each cylinder. an exact quantity of fuel is delivering to
each cylinder at the appropriate time.

Conventionally, petrol (or gasoline) engines are also called spark ignition (SI) engines. it uses a
carburetor to mix air and fuel but it has poor response acceleration and deacceleration to the system. this
carburetor also has a big problem with increased emissions. The purpose of these fuel injectors is to
inject a precise quantity of fuel into the chamber.

Read more: Everything you need to know about automobile piston

Functions of multi-point fuel injection

Below are the functions of a multi-point fuel injection system in gasoline engines:

 Just as earlier mentioned, the primary function of MPFI is to inject a precise quantity of fuel into
the combustion chamber.

 These systems also produce better atomization and a swirl of fuel in the combustion chamber.

 It reduces the difference in power in each cylinder.

Read more: Difference between fuel injection and carburetor

Components of a multi-point fuel injection

Below are the components of multi-point fuel injection in an automotive engine:

 Fuel pressure regulator

 Fuel injectors

 Cylinders

 Pressure spring

 Control diaphragm
Multi-point fuel injection diagram:

Read more: Things you must know about connecting rod

Types of multi-point fuel injection system

(MPFI)
There are three types of multi-point injection system which include:

 Batched MPFI system

 Simultaneous MPFI system

 Sequential MPFI system

In a batched MPFI system, fuel is injected into a group or batches of the cylinders without bringing their
intake stroke together.

In a simultaneous system, fuel is inserted into all cylinders at the same time. And finally,

In a sequential MPFI system, the injection is timed to overlap with the intake stroke of each cylinder.
Read more: Everything you need to know about the camshaft

Working principle
Just as with other fuel injection methods in internal combustion engines, the working of a multi-point
injection system is less complex and can be easily understood. In the system, multiple individual injectors
are used to inject fuel into each cylinder through an intake port situated upstream of the cylinder’s intake
value.

The fuel pressure regulator is connected to the fuel rail employing an inlet and outlet to direct the flow of
the fuel. At the same time, the control diaphragm and pressure spring control the inlet valve opening and
the amount of fuel that can return. The engine speed and load are change by the pressure in the intake
manifold.

Watch the video to learn more about how a multi-point fuel injection
system works:
Read more: Things you need to know about Turbocharged Engines
Join our Newsletter
submit

Advantages and disadvantages of a multi-point

fuel injection (MPFI) system
Advantages:
Below are the advantages of a multi-point injection system on gasoline engines:

 The system is reliable

 It reduces the difference in power that each cylinder creates.

 It increases the fuel efficiency of an engine

 Better atomization of fuel

 MPFI system have fewer emissions

 Better utilization and distribution of fuel within an engine.

 Better acceleration and deacceleration of engine

 It improves the cold start properties of the engine

 Vibrations in reduce in the engine

 Improves durability and functionality of an engine

Read more: Understanding Spark Plug
Some other benefits include:
 Easy engine tuning

 Initial and maintenance cost

 Smooth operations and drivability

 Diagnostic capability

 Ability to work with alternative fuels

Disadvantages:
Despite the various advantages of multi-point fuel injection, some limitations still occur. below are the
disadvantages of multi-point fuel injection MPFI system in internal combustion engines:

 Misfiring might occur sometimes

 It requires regular inspection of fuel injectors

 The system is expensive compared to conventional systems.

 Repairing fuel injector can be tedious compared to carburetors

 The system usually has a shorter life.

 ECU failure could occur suddenly.

 A hot engine might be difficult to start due to possible vapor lock in the steel fuel lines above the
engine.

MPFI (Multi point Fuel Injection) System,Electronic Fuel injection

 aermech    August 18, 2014    8 Commentson MPFI (Multi point Fuel Injection) System,Electronic Fuel

injection

Fuel injection is a method or system for admitting fuel into the internal combustion
engine. From early 1940s many injection system like single-point injection, continuous
injection are introduced in the market by the different companies. But presently the most
used injection system are MPFI in petrol engine and CRDI in diesel engine.
 MPFI (Multi point Fuel Injection) System,Electronic Fuel injection

Multi Point Fuel Injection System

Petrol vehicles uses device called carburetor for supplying the air fuel mixture in correct
ratio to cylinders in all rpm ranges. Due to construction of the carburetor is relatively
simple, it has been used almost exclusively on gasoline engines in the past. However
presently we need cleaner exhaust emission system, more economical fuel
consumption, improved drivability, etc.

So in order to get all these , we need a carburetor that must have various devices to do
the above functions, making it more complex system. So In place of the carburetor,
therefore, the MPFI (multi point fuel injection) system is used, assuring proper air fuel
ratio to the engine by electrically injecting fuel in accordance with various driving
condition.

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Multi point fuel injection system injects fuel into the intake ports just upstream of each
cylinder’s intake valve, rather than at the central point within the intake manifold.

Multi point fuel injection systems are of three types, first is BATCHED in which fuel is
injected to the cylinders in groups, without precisely bringing together to any particular
cylinder’s intake stroke, the second one is simultaneous in which fuel is injected at the
same time to all the cylinders and the third one is sequential in which injection is timed
to coincide with each cylinder’s intake stroke.

BMW uses Old technology Water Injection system In its new cars click to know
more.

ADVANTAGES OF MULTI POINT FUEL INJECTION

SYSTEM
 More uniform air-fuel mixture will be supplied to each cylinder, hence the difference in
power developed in each cylinder is minimum.
 The vibrations produced in MPFI engines is very less, due to this life of the engine
component is increased.
 No need to crank the engine twice or thrice in case of cold starting as happen in the
carburetor system.
 Immediate response, in case of sudden acceleration and deceleration.
 The mileage of the vehicle is improved.
 More accurate amount of air-fuel mixture will be supplied in these injection system. As a
result complete combustion will take place. This leads to effective utilization of fuel
supplied and hence low emission level.

Multi-Point Electronic Injection System

(Automobile)
9.25.
Multi-Point Electronic Injection System
A complete electronic system uses a solenoid-operated
fuel injector, which works intermittently and opens at
set times in the engine cycle. It remains open for a
period of time, which is proportional to the quantity of
fuel required. A number of different types of full
electronic system are in use. The main difference
among them is the method of measuring the air flow.
The two main measuring systems are:
(i) Indirect or pressure-sensed air flow measurement.
(ii) Direct air flow measurement.
9.25.1.
Pressure-sensed Air Flow System
This system uses a manifold absolute pressure (MAP)
sensor to measure the manifold depression. The ECU
receives signals from the MAP sensor and, after
analysing the data receiving from the other sensors, the
ECU directs the injector to open for a set time,
proportional to the quantity of air received by the
engine.

Bosch D-Jetronic.
This system is an example of a pressure-sensed
system (The letter ‘D’ stands for Druck, which means
pressure in the German language). The basic layout of
this type of system is shown in Fig. 9.99 where the
quantity of air induced into the engine for a given
throttle opening depends on the manifold pressure. A
MAP sensor measures the manifold pressure and
sends an electrical signal to the ECU to indicate the
quantity of air entering the engine. After processing the
signal, the ECU determines the period of time for the
injector to remain open.
Commencement of injection is triggered by either a
switch in the ignition distributor or a sensor placed
adjacent to the flywheel or crankshaft pulley. For six-
cylinder engines, the injectors are operated in sets of
three, i.e. three injectors spray at the same time. Extra
fuel
provision for cold starting is similar to that used in the
K-Jetronic. The ECU receives messages from a
number of sources (Fig. 9.100), and after processing
the data as per the instructions programmed into its
built-in memory, the ECU signals the injectors to
operate accordingly. Some of the other items that are
used to control the system are shown in Fig. 9.101. The
throttle position switch works in conjunction with the
MAP sensor for measurement of air flow.

Fig. 9.99. Basic layout of electronic system of

petrol injection.
Fig. 9.100. Input and output signals of electronic
system.

Fig. 9.101. Bosch D-Jetronic electronic system of

fuel injection.

9.25.2.
Direct Air Flow System
In this system air, entering into the engine, is measured
by vane (flap) or hot-wire metering. Both of these
sensors produce voltage output, which is proportional
to the rate of airflow. This voltage signal is passed to
the ECU for computation of the fuel requirement, which
is governed by the time period of opening of the
injector. Both the sensors take into account of the
actual density of the air entering the engine to
compensate for variations in atmospheric temperature
and pressure. This feature is especially significant to
maintain the required air-fuel ratio when the vehicle
operates at different altitudes.
Vane or Flap Metering. The layout of a system, shown
in Fig. 9.102, is similar to a Bosch L-Jetronic. (The L
stands for Luft, the German word for air). The flap
sensor works in a similar way to a spring-loaded rigid
flag, exposed to air movement. As the force on the flag
increases with the air speed (or density), it moves
through an angle to a position where the force of the air
equals the reaction of the spring. In the case of the
vane, the position it occupies for a given air flow is
recorded by a potentiometer.
Other than the arrangement for sensing the air flow, the
basic system is similar to one described previously. An
electrically driven fuel pump produces fuel pressure,
which is maintained constant at 196 kPa by a pressure
regulator. Injector valves are actuated once in every
crankshaft revolution and fuel quantity is controlled by
the period of opening of the injector by the solenoid.

Fig. 9.102. Van or flap metering (Bosch LE-

Jetronic).
Hot-wire Metering.
The principle of the system, illustrated in Fig. 9.103, is
based on the cooling of a hot surface, due to air blown
over it, and the rate of heat transfer depends on the
rate of air flow. Both the Lucas EFI and the Bosch LH-
Jetronic employ this method of air flow measurement.
The hot wire element of the sensor is heated by an
electric current, which is sufficient to maintain it at a
constant temperature. The cooling action increases
with the increase of air flow, and therefore to maintain
the temperature taking account of the losses, a larger
current has to be passed through the wire filament. The
voltage corresponding to this current provides an
indication of the air flow. The ECU receives this voltage
to compute the basic quantity of fuel, which is then
slightly altered taking into consideration of the signals
received from other engine
sensors.
!

Fig. 9.103. Hot-wire sensing.

As the air temperature affects the accuracy of the
system, a compensating resistor is placed in the air
stream. A change in air temperature causes the resistor
to alter its resistance, which compensates for the effect
of a change of air temperature. Hot-wire sensing
system controls air-fuel ratio within the limits required to
meet emission regulations in force in various countries,
and hence today this system is employed in many cars.
9.25.3.
Fuel System
Even though many different electronic systems of
control are in use, the basic fuel supply system and the
supporting electrical circuitry are often similar. A typical
fuel supply system is now described to explain the
basic principal of the main hydraulic components.
Figure 9.104 shows the main components of the fuel
system. The fuel supply system uses the injectors
(described in section 9.26) with adequate fuel at a
pressure sufficient for the injectors to provide good
atomisation. The fuel pressure must not vary as the
quantity of fuel injected depends on this pressure.

Fig. 9.104. Fuel System.

Pump.
Generally a roller-type rotary pump is used, which is
operated by a permanent-magnet electric motor (Fig.
19.105). The rollers move outwards with the rotation of
the pump and seal the spaces between the rotor and
casing. Since the fuel is carried around with the rotor,
the pressure increases due to the rotor movement
combined with the decrease in volume of the pumping
chamber. The pump supplies fuel through the motor to
assist cooling. More quantity of fuel is supplied than
required, and excess fuel is re-circulated back to the
tank, which reduces the vapour lock problems.

Fig. 9.105. Fuel pump and electrical supply circuit.

Two ball valves are installed in the pump; a non-return
valve at the outlet and a pressure relief valve, to limit
the maximum pressure. An ECU controls the pump
through a pump relay, and the current to the pump
passes through a ballast resistor to drop the voltage to
7 V. This resistor is shorted-out during engine cranking
to compensate for the lower battery voltage.
The pump motor runs for a short period when the
ignition is switched on, to fully pressurize the system.
After this operation, the pump is stopped until the
engine is cranked. As a safety measure, an inertia
switch is installed in the electrical supply line to the
pump relay. This switch opens if it is jolted, so when a
collision takes place, the pump ceases to operate. The
switch can be reset by pushing down a protruding
plunger.
Fuel Pressure Regulator.
This regulator controls the operating pressure of the
system and

Fig. 9.106. Pressure regulator.

maintains a constant pressure difference of 245 kPa,
the set value, between the fuel line and the inlet
manifold irrespective of throttle opening. The regulator
uses a spring-loaded diaphragm and ball valve
(Fig.9.106).
Manifold depression depends on throttle opening e.g.
engine load. When the throttle opening is small the high
depression causes more fuel to leave the injector. This
is compensated by lowering the fuel system operating
pressure when the manifold depression is high. To
achieve this, one side of the regulator is connected to
the induction manifold. When the engine operates
under a light load, the regulator valve is slightly opened
to reduce the pressure. The regulator controls the
pressure to 176.5 kPa when engine is idling with very
high manifold depression and 245 kPa when engine is
at full throttle with very low manifold depression.
Sequential fuel injection, also called sequential port fuel injection (SPFI) or timed
injection, is a type of multiport injection. ... Timed like spark plugs, they spray the fuel
immediately before or as their intake valve opens.

How does sequential fuel injection work?

Basically, a SFI (sequential fuel injection) system has a fuel injector for each cylinder. ...
This air/fuel mixture is pulled into the cylinder past the intake valve on the intake
stroke of the piston and is then compressed and ignited.

Chrysler Turbo Sequential Multiport Injection Fuel System

Fuel Injector Flow Chart and Horsepower Levels

Chrysler uses a Speed/Density-based, Sequential Multiport Injection

system with the 1990-91 Turbo SBEC  to control the fuel delivery. Unlike a
mass air flow system the speed/density system does not recognize the
increase in air flow and hence tends to lean out at higher power levels (not a
good thing at higher boost levels, if you like your pistons! Just remember:
LEAN = MEAN, but FUEL is POWER)

Sequential Multiport systems offer better control of the injector at low and

high pulse widths do to several facts.  Earlier (1989 and earlier) Mopar "Batch
Fired" systems fire half the injectors at once and the injectors are fired every
engine revolution.  Sequential systems fire each injector just like the spark
plug, each injector can be controlled as to the time it fires relative to the spark
(phasing), the amount of fuel delivered and any cylinder fuel trim desired.  The
Sequential system fires once every two engine revolutions (once every 720
degrees) on a four cycle engine.

Also, when higher HP outputs require that injectors are chosen with "low
impedance (Z)" coils (Mopar chose low-impedance, 2.4-ohm injectors) and
large flow rates are required, these low-Z injectors must often operate at very
low pulse widths at idle.  Hence the double fire, batch or bank/bank operation
modes can not offer the desired idle quality.

On the other hand, Sequential-fired injection systems can offer individual

cylinder control often used in racing where air flow to different cylinders is not
the same and small corrections are desired to make the air-to-fuel ratio to all
cylinders exactly the same to get the ultimate performance possible.  The
sequential system will have also have greater control of the injector at high
pulse widths and slightly extend the injectors usable working range. 

The numbers you see listed in this chart represent what have generally been
reported to be safe dyno-measured horsepower levels for these different sizes
of injectors.  Remember,  with a speed/density-based ECM system, if you
increase or adjust static fuel pressure you will increase the horsepower level
you can attain, within reasonable limits. This is where an adjustable (or rising
rate) fuel pressure regulator can help you bridge the gap between injector flow
rates.

To meet our desired output goals of 100 bhp per litre, (250 bhp), we'll be using
the +20% (P4529495)  42  lbs/per hour injectors, which theoretically max out
at 260 hp.

What is direct injection used for?

Direct injection allows for more control during the fuel delivery process by
atomizing the spray of fuel in the cylinder, providing better distribution of fuel
throughout the combustion chamber and allowing the implementation of advanced
engine management protocols such as Variable Valve Timing.
What is direct and indirect injection?
Indirect injection in an internal combustion engine is fuel injection where fuel is not
directly injected into the combustion chamber. ... Direct injection allows the fuel to be
precisely metered into the combustion chamber under high pressure which can lead to
greater power, fuel efficiency.
Do direct injection have spark plugs?
Direct injection is more efficient than multi-port. ... Relatively new for gasoline, direct
injection has always been used on diesel engines, which depend on compression
heat rather than a spark plug to ignite the fuel.

Engines with gasoline direct injection produce the air-fuel mixture directly in the
combustion chamber. Only fresh air flows into the intake port through the open intake
valve. The fuel is injected directly into the combustion chamber by high-pressure
injectors.

irect Injection Basics

With direct injection engines, fuel is squirted directly into the combustion chamber instead of
hanging out in the air intake manifold.

© 2009 HOWSTUFFWORKS

For the lay individual, the labyrinth of hoses, wire harnesses, manifolds and tubing
beneath a car hood might appear intimidating. But when it comes to the gasoline
engine, just know this: It needs fuel, air (oxygen, to be precise) and spark in order to
operate.

The two most critical differences between a direct injection engine and a standard
gasoline engine are how they deliver fuel and how the fuel mixes with incoming air.
These basic premises make a tremendous difference in an engine's overall efficiency.

Before we look inside the direct injection engine, let's view a quick second in the life of a
standard gasoline engine (for a more complete look at the gasoline engine, check
out How Car Engines Work). First, the fuel travels via pump from the fuel tank, through
the fuel line and into fuel injectors that are mounted into the engine. The injectors spray
gasoline into the air intake manifold, where fuel and air mix together into a fine mist. At
precisely timed intervals, intake valves open, corresponding to the different cylinders of
the engine. As a cylinder's intake valve opens, a piston in that cylinder descends,
sucking the fuel-air mist from the air manifold above into the chamber below. As the
piston ascends once more, it squeezes (compresses) the fuel-air mix until it is nearly
nine times as dense as it was to begin with. Then, that cylinder's designated spark
plug fires, igniting the chamber into a high-pressure, high-energy explosion. This little
bang pushes the piston back down with tremendous force, causing it to turn the
crankshaft and ultimately send power to the wheels.
Got that? Pretty complicated, huh? It works, but from an engineering standpoint, it
leaves much to be desired, and it's pretty wasteful.

With a direct injection engine, however, the fuel gets to skip a step and add a bit of
efficiency. Instead of hanging out in the air intake manifold, fuel is squirted directly into
the combustion chamber. With an assist from modern engine management computers,
the fuel gets burned right where it's needed, when it's needed
[source: Fueleconomy.gov].

Direct Fuel Injection

The What and How of the Fuel Delivering Technology

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 Direct injection system with the injector on the far right at the top of the cylinder.
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By 
Aaron Gold
Updated January 13, 2019

Direct fuel injection is a fuel-delivery technology that allows gasoline engines

to burn fuel more efficiently, resulting in more power, cleaner emissions, and
increased fuel economy.
How Direct Fuel Injection Works
Gasoline engines work by sucking a mixture of gasoline and air into a
cylinder, compressing it with a piston, and igniting it with a spark. The
resulting explosion drives the piston downwards, producing power. Traditional
indirect fuel injection systems pre-mix the gasoline and air in a chamber just
outside the cylinder called the intake manifold. In a direct injection system, the
air and gasoline are not pre-mixed. Rather, air comes in via the intake
manifold, while the gasoline is injected directly into the cylinder.
Advantages of Direct Fuel Injection
Combined with ultra-precise computer management, direct injection allows
more accurate control over fuel metering, which is the amount of fuel injected
and injection timing, the exact point when the fuel is introduced into the
cylinder. The location of the injector also allows for a more optimal spray
pattern that breaks the gasoline up into smaller droplets. The result is more
complete combustion. In other words, more of the gasoline is burned, which
translates to more power and less pollution from each drop of gasoline.

Disadvantages of Direct Fuel Injection

The primary disadvantages of direct injection engines are complexity and
cost. Direct injection systems are more expensive to build because their
components must be more rugged. They handle fuel at significantly higher
pressures than indirect injection systems and the injectors themselves must
be able to withstand the heat and pressure of combustion inside the cylinder.

How Much More Powerful and Efficient Is the Technology? 

The Cadillac CTS is sold with both indirect and direct injection versions of its
3.6-liter V6 engine. The indirect engine produces 263 horsepower and 253 lb.-
ft. of torque, while the direct version develops 304 hp and 274 lb.-ft. Despite
the additional power, EPA fuel economy estimates for the direct injection
engine are 1 MPG higher in the city (18 MPG vs. 17 MPG) and equal on the
highway. Another advantage is that Cadillac's direct injection engine runs on
regular 87-octane gasoline. Competing cars from Infiniti and Lexus, which use
300 hp V6 engines with indirect injection, require premium fuel.
Renewed Interest in Direct Fuel Injection
Direct injection technology has been around since the mid-20th century.
However, few automakers adopted it for mass-market cars. Electronically-
controlled indirect fuel injection did the job nearly as well as a significantly
lower production cost and offered huge advantages over the mechanical
carburetor, which was the dominant fuel delivery system until the 1980s.
Developments such as rising fuel prices and stricter fuel economy and
emissions legislation have led many automakers to begin developing direct
fuel injection systems. You can expect to see more and more cars make use
of direct injection in the near future.

Diesel Cars and Direct Fuel Injection

Virtually all diesel engines use direct fuel injection. However, because diesel
engines use a different process to combust their fuel, where a traditional
gasoline engine compresses a mixture of gasoline and air and ignite it with a
spark, diesels compress air only, then spray in fuel which is ignited by the
heat and pressure, their injection systems differ in design and operation from
gasoline direct fuel injection systems.
How Multi-Port Injection and Direct Injection work

Conventional fuel injection (MPI)

In a gasoline engine with a conventional multi-port (multi-point)
fuel injection, an electric fuel pump built inside the gas tank delivers
the fuel to the engine fuel rail. The fuel pressure is relatively low: 35-
60 psi. The fuel rail distributes the fuel to the injectors. Each cylinder
has one fuel injector (green in the image). When commanded by the
engine computer, a fuel injector sprays fuel into the intake port
where it mixes with air. From there, the air /fuel mixture enters the
cylinder through an open intake valve during an intake stroke.

Direct fuel injection (GDI)

In a direct injection, a low-pressure fuel pump delivers fuel to the

added high-pressure fuel pump first. A high-pressure fuel pump is a
mechanical pump driven by one of the engine camshafts. It supplies
fuel under very high pressure (over 2,000 psi) to the fuel rail. A fuel
rail distributes the fuel to the high-pressure fuel injectors; one per
each cylinder. A high-pressure fuel injector vaporizes fuel directly
into the combustion chamber during the compression stroke, when
the piston is close to the top, see the image.
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Does a direct-injected engine require more maintenance?

If you check a maintenance schedule for a direct-injected car, you
won't likely find any additional services for the direct injection. There
are however, a few differences. First, a direct injected engine is more
sensitive to the gasoline quality, considering the design.

A high pressure fuel pump is driven by a camshaft and this friction

point is lubricated by engine oil. 

Ford EcoBoost high-pressure fuel pump

This means that a low oil level or lack of oil changes can cause
problems, but this is true for any engine.

The one problem area specific to direct injection is a carbon buildup

on the back of intake valves and on the injectors. Why does this
happen? In any engine, oil vapors from a crankcase ventilation
system flow through the intake valves. However, In a conventional
MPI fuel injection, injectors spray directly on intake valves,
"washing" them off. In a direct-injected engine, fuel is sprayed
"under" valves, see the images above. This means that over time, oil
vapors from the ventilation system passing through intake valves
form carbon deposits on the backside of the valves and on the
injectors.

This problem is more noticeable in high-mileage engines, especially

if the vehicle is used for frequent short trips. A turbocharger can
also make things worse, because at higher mileage, oil leaking from
turbocharger seals also ends up in the intake.

This means, that in some direct-injected cars, intakes valves may

need cleaning at higher mileage. 

Audi high pressure fuel pump. Audi calls direct injection Fuel Stratified Injection or FSI/TFSI

If you take your direct-injected vehicle for a tune-up, a dealer or an

independent repair shop may offer you a fuel induction service or
intake valve cleaning service. Many BMW owners, for example, know
about "Walnut blasting" which is a way to clean the intake valves
with black walnut shell media ($450-$700). Sometimes intake valves
may need to be cleaned manually and this could cost a bit more.
We spoke to an owner of a repair shop specializing in German cars.
He recommends cleaning the intake valves every 75,000 miles.
According to him, deposits on the intake valves is one of the
common problems his shop deals with.

That said, many direct-injected cars don't have any problems. We

also found several service bulletins where different auto makers
recommend using TOP TIER Detergent Gasoline to avoid problems
with a direct injection: Check www.toptiergas.com for the list of fuel
suppliers that offer TOP TIER Detergent Gasoline.

There is some progress in DI technology too. Toyota, for example,

uses D-4S Fuel Injection in a number in recent Toyota and Lexus
vehicles. In the D-4S engine, each cylinder has both, a direct injector
and a port injector. Ford also implemented a dual fuel delivery
system with two fuel injectors per cylinder in some of the latest
models. It's called PFDI- Port Fuel (PFI) and Direct-Injection (DI). This
dual-injector technology should eliminate problems with carbon
buildup on the intake valves.
Are direct-injected engines reliable?
 Mazda Skyactiv direct-injected engine

In general, the more complex the car, the more can go wrong,
although some cars have had more problems related to direct
injection than others. For example, BMW has had some problems
with high pressure pumps and injectors and even issued a recall for
a high pressure fuel pump in some models. Volkswagen/Audi had
issues in their gasoline 2.0L-turbo FSI (Volkswagen term for direct
injection) motor with the high pressure fuel pump follower/cam
lobe wearing out. However, for example, Mazda Skyactiv direct-
injected gasoline engines generally hold up well with regular oil
changes. This means, check the reliability for any car individually.

Where can you check the reliability ratings? First, there is Consumer
Reports. We find their ratings to be accurate. To access their ratings
online, you would need a paid subscription, but you might be able
to find a copy of their printed magazine in a local library. J.D.
Power also offers dependability ratings.
Check CarComplaints.com to know which cars have more problems.
Pros and cons

To summarize: drawbacks of a direct injection include a more

complex design with expensive components, tougher requirements
to the gasoline quality and potentially greater repair costs at higher
mileage due to problems mentioned above. Often, some of these
problems are difficult to diagnose, adding to the repair bill.
The main benefits are better fuel economy, lower emissions and
potential for more power.
What to look for when buying a used car with a direct-injected engine?

When checking a car with direct injection, watch out for the Check
Engine light staying on after the engine is started.
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Avoid a car if there is a gasoline smell noticeable under the hood. A
low engine oil level can be an indication of excessive oil
consumption. Too high oil level and a gasoline smell may indicate
gasoline presence in engine oil, which is also not a good sign. When
test-driving the car, watch out for abnormal engine noises, as well as
lack of power, misfiring, rough idle or hesitation. Stalling is another
sign of engine troubles. A blue or white smoke from the exhaust
should tell you to pass on the car. Read more: How to inspect a
used car.
We would recommend having the vehicle inspected by a trusted
mechanic before signing the contract. If it's a German car, take it to
the mechanic specializing in German cars. Avoid the car if it shows
signs of lack of maintenance.

Read More:
What you should know before buying a used car
Should you buy a turbocharged car?
Should you buy a car with a continuously variable transmission or CVT? Pros and Cons
What mileage is OK for a used car?
How do I get the best deal on a used car?
How to inspect a used car - illustrated guide
How to spot signs of accident repair, rust or paint job
How to check an engine when buying a used car
Reviews of popular used cars including problems to watch out for.
Reviews of popular used SUVs.

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 S

Here's an Incredibly Detailed Explaination of How

Direct Injection Works
Want to learn everything there is to know about direct injection engines? Start here.
BY BRIAN SILVESTRO

FEB 26, 2018

BOSCH GERMANY / SAVAGEGEESE

Direct-injection engines are pretty common in new cars these days, but
how exactly do they work? Well, this explainer video put together by the
YouTubers at SavageGeese gives us an in-depth look at the inner
workings of direct injection and its many variations.

Unlike other types of fuel delivery, which get fuel into the combustion via
the intake, direct injection places a high-pressure injector directly into
the cylinder head, allowing fuel to be shot directly into the chamber,
meaning a more precise delivery and ignition process. Though direct
injection systems are usually more expensive and complex, they allow
manufacturers to draw more fuel efficiency and power from their
motors, which is why the technology is so widespread.

SavageGeese put together an extremely detailed video that goes into

detail about how direct injection works, its shortfalls, and how it
compares to other types of fuel delivery systems. Watch for yourself
below.