Technical Manuals

Classification of automotive injection

systems
Electronic injection is a form of fuel dosing, both for gasoline engines, in which it
has been implemented for several decades, and for diesel engines, whose
introduction is relatively more recent. It can be subdivided into several types
(single point, multipoint, sequential, simultaneous, etc.) and is based on the help
of electronics to deliver fuel injection and reduce the emission of polluting agents
into the atmosphere and, at the same time, optimize the consumption and
performance of the vehicle. This system has replaced the carburettor in gasoline
engines. Its introduction was due to an increase in the demands of environmental
control agencies to reduce engine emissions. In diesel engines, the injection
pump, which has mechanical injectors, has been replaced by a high-pressure
pump with electro-hydraulic injectors.

INTRODUCTION In this case the lambda factor is equal to 1.

Electronic injection systems have a better

capacity, compared to the carburettor, to dose the
fuel and dose the air/fuel mixture, that is, the lambda
factor so that it is very close to the stoichiometric
formula (14.7:1 for gasoline), which implies a lambda
factor close to 1, which guarantees very good
combustion with a reduction in the percentage of toxic
gases emitted into the atmosphere. The
stoichiometric ratio is the exact proportion of air and -
fuel that ensures complete combustion of all the fuel.
Technical Manuals
The function of injection in gasoline engines is: a single injector. Fuel injection takes place in the

Classification of Electronic Gasoline Injection according to the

* Measure the ambient air drawn in by the
engine type where the injection is performed and the number
engine, controlled by the driver using the throttle of injectors used by the system
valve, depending on the engine load required in
each case, in order to adapt the fuel flow to this throat of the intake manifold, also called the throttle
measurement and in accordance with the engine body, above the throttle butterfly.
operating regime,
* Dosing by injection the quantity of fuel required In the “Multipoint Injection System - (MPI -
Multipoint Injection)”, injection takes
by this quantity of air, necessary for combustion to be
as complete as possible, that is, maintaining the
YO# place in front of the intake valve of each
stoichiometric proportion as far as possible, within the cylinder. Use one injector per cylinder.
limits of the lambda factor. Direct Injection
* Complete the combustion function together with
Fuel injection takes place directly into the
the ignition of the engine.
combustion chamber of each cylinder. It uses one
In diesel engines, the function of electronic injector for each cylinder (GDI - Gasoline Direct
injection is to regulate the amount of diesel injected Injection) and is known as the MPI system
based on the engine load (accelerator pedal), “Multipoint Direct Injection System”.
synchronizing it with the engine speed and the firing
In Figure 2 we can see another way of classifying
order of the cylinders. In the case of the diesel
engine, the air supply is not controlled, only the fuel gasoline injection systems according to the strategy
supply. It consists mainly of sensors, an electronic carried out by the on-board computer or electronic
control module (ECU) to activate the injectors.
control unit and actuators.

CLASSIFICATION OF INJECTION SYSTEMS

Fuel injection systems in gasoline vehicles are

classified based on the way the fuel is placed into the

NAFTA INJECTION
Figure 1

INDIRECT SINGLE POINT MULTIPOINT

The “Throttle Body Injection (TBI)” system uses
engine cylinders to carry out the combustion
Classification of Electronic Injection
process.
according to the strategy used by the Electronic Control Module (
In Figure 1 we can see a classification
ECU) for the activation of the injectors
system according to the point in the engine
where the injection is performed and the
NAFTA INJECTION Figure 2
number of injectors used by the system.

DIRECT
SINGLE POINT MULTI POINT i
Indirect injection MUI
I,i
It can be single point or multipoint. SMULTAHEAl SEMI SEQUENTIAL|[SEQUENTIAL
TIPOINTSEQU
 Classification of Automotive Injection Systems
Single Point Indirect Injection Controlled by for each revolution of the crankshaft. With this
strategy, most injections occur with the
intake valve closed, in case the cylinder is
in the compression, expansion, or
discharge (exhaust) phases. The fuel
injected during these phases is
accumulated in the intake manifold to be
admitted when the intake valve opens. Up
to four injections can be accumulated per
cylinder. This rich mixture makes starting
the engine easier. Once the engine starts,
the ECU, based on its program, changes
the strategy, ordering a simultaneous
injection for each crankshaft revolution. In
the ECU this way the number of accumulated
injections for each cylinder before the intake valve
In this system, the ECU follows two different opens is two injections. Table 1 summarizes the
strategies to control the amount of fuel to be injected injection strategy managed by the ECU in a
into each element, to determine when to trigger the simultaneous injection system.
opening of the single injector.
Semi Sequential Injection:
Synchronous operation: The opening of the It is also called Bank to Bank. In these systems
injector is synchronized with the ignition. Each time and during the engine start-up phase, the ECU orders
the ECU gives the order for ignition to occur, it orders the opening of all the injectors at the same time,
an injection. This action generates two injections per producing two injections for each crankshaft
crankshaft revolution. revolution.
With this strategy, most injections occur with the
Asynchronous operation: Under certain engine intake valve closed, whether the cylinder is in the
operating conditions, for example at high revs or with compression, expansion, or discharge (exhaust)
very short injection times and due to the phases. The fuel injected during these phases is
electromechanical inertia of the injectors, the ECU no accumulated in the intake manifold to be admitted
longer injects every time it orders an ignition but when the intake valve opens.
rather follows what is established in the program During start-up, all the injectors open at the same
contained in its memory for those engine operating time, similarly to what we have already seen in figure
conditions. 3, while during normal engine operation, every half
turn of the crankshaft they open twice.

Multipoint Indirect Injection

Controlled by the ECU

In a Multipoint System there is one injector for

each cylinder and they are managed by the ECU in a
specific way for each particular system.

Injection into each cylinder occurs in front of the

intake valve.

Simultaneous Injection:
In these systems, the ECU orders the opening of all
the injectors at the same time, figure 3.
When the engine is started, two injections are made
 Technical Manuals

Injection strategy managed by the Electronic Control Module (ECU)

in a Simultaneous Injection System

CYLINDERS Engine cycle condition ENGINE OPERATION

Yo 2 3 4
compression expansion admission discharge Start of cycle 0° to START
• 180°
« ■ * For each ignition, one
inj
bone injection is
expansion discharge compression admission produced
*• 180° to 360°
/inj
download
"=
admission
%
expansion compression
2 injections per
crankshaft revolution
3600 to
\
iqgnjiny
ad mission
■*
Comprehension download expansion
End of the cycle

#*#
ign / inj % ★♦ 540° to 720*
NORMAL
compn ession expansion admission discharge Start of cdo

_V
*
mem •* 0° to 180*
For every two ignitions,
expansion discharge compression admission
an injection occurs
180° to
*
ivn riny •
discharge
to#
admission expansion
•mu
compression
□ be
1 injection per crankshaft
rail 360* to 540* revolution

atnsiüf
=▼ \
compI eslün d Download expansion
End of the cycle
. finy ib M

compression
■
expansion
♦*
admission
*
download
540° & 720*

Start of ocle 0° to

iryn W
« w 180°

* - 1 cumulative injection
# *-2 I—*—I Number of injections
cumulative injections ,„ | ] accumulated at the time
Indies
Indica # ** -3 cumulative injections | | that the valve opens
# *** - 4 cumulative injections #*** admission of that cylinder

”» - Turning on the
Indica _ % Air/Gasoline mixture Table 1
injectors at the same time, leaving the other two two.
closed (Figure 4). Injectors 1 and 4 open together, Table 2 shows the injection strategy used by the
while injectors 2 and 3 remain closed and vice versa. ECU in a semi-sequential or Bank to Bank injection
Up to four injections can be accumulated per cylinder. system.
This rich mixture makes starting the engine
easier. Sequential injection
Once the engine starts, the ECU has already In these systems and during the engine start-up
identified the cylinders that are in upstroke through phase, the ECU orders the opening of all the injectors
the information it receives from the RPM and TDC at the same time, producing two injections for each
sensor and based on its program it changes the crankshaft revolution. With this strategy, most
strategy, ordering a simultaneous injection for each injections occur with the intake valve closed, in case
pair of cylinders, activating the injectors the cylinder is in the phases of
corresponding to cylinders 1 and 4 at the same time
and then after half a turn of the crankshaft, those -
corresponding to cylinders 2 and 3 at the same time.
In this way the number of accumulated injections for
each cylinder before the opening of the intake valve is
 Classification of Automotive Injection Systems

compression, expansion, or discharge (exhaust). The

fuel injected during these phases is accumulated in
the intake manifold to be admitted when the intake
valve opens. Up to four injections can be
accumulated per cylinder.
This rich mixture makes starting the
engine. During start-up, all 4 injectors operate at the
same time, as we have already seen in figure 3. Now,
during normal operation, every half turn of the
crankshaft
Figureopens
4 the injector corresponding to the
cylinder that is in the intake phase, as we can see in
figure 5.

Injection strategy managed by the Electronic Control Module (ECU) in a Semi Sequential Injection
System! or Bank to Bank

CYLINDERS Engine cycle r ANOINTING AM It ti

condition TO Ut IMP IO ft
Yo 2 3 4
compression expansion admission discharge Start of cycle 0" to
inj * # ■* # 180 START Injects
simultaneously into all
expansion discharge compression admission
180° to 360° cylinders 2 times for
ignriny
** #* *% ** each turn of the
discharge admission expansion understanding crankshaft
360° 540-
ign / inj #** #** ** *\
admission compression I fell down expansion End of cycle 540° to
ign NORMAL
720°
inj. 1 and 4 **** #* **
Once the ECU
ign compression expansion admission discharge identifies the cylinders in
Start of cycle O' A 180-
inj. 2y3 * *** ** intake rate, injection
and
begins to be carried out
expansion download understanding admission per pair of cylinders at a
ign 1800 to 360-
Inj. 1 and 4 H * *** time.

discharge admission expansion compression Cylinders 1 and 4

ign 360° to 540• simultaneously
inj. 2 and 3 * #* # ¥
ign inj. 1 admission compression discharge expansion End of cycle 540° 0 Cylinders ty 3
720- simultaneously
and 4 #* * *
compression expansion admission discharge the 0a
Beginning of
ign
inj, 2 and 3 N He ** * atheist cycle*
expansion discharge compression admission
ign 1800a360•
inj. 1y4 * * TO **

* - 1 injection 3 cumulative
Indica ** - 2 cumulative injections Indica # Number of injections
#* accumulated at the moment
#** - 3 cumulative injections #** the valve opens
#*** - 4 cumulative injections #**4 admission of that cylinder

Indicate < - Turning on the

sF _ ' Air/Gasoline mixture Table 2
 Technical Manuals

Once the engine starts, the ECU has already * By admitted air flow.
identified in which crankshaft position each cylinder is * Due to the position that the butterfly takes
in the intake phase. It achieves this through the depending on the engine RPM.
information it receives from the phonic wheel and the * Due to the density of air admitted based on the
phase sensor and based on its program it changes engine RPM.
the strategy, ordering the opening of the injector * By the air mass.
corresponding to the cylinder that in the intake phase
is mechanically opening its intake valve.
The fuel dosing achieved with this system is much By Admitted Air Flow
more precise than in the two systems described
The Electronic Control Module has stored in its
above.
memory a “Basic Injection Time Table” based directly
In Table 3 we can observe the strategy used by
on the Admitted Air Flow.
the ECU in a sequential injection system.
The air flow that is being admitted at any given
time by the engine is reported to the ECU by the flow
CLASSIFICATION OF INJECTION SYSTEMS meter. According to the information received, she
ACCORDING TO THE INJECTION TIME searches her memory for the Base Opening Time that
she should apply to the injectors. This time is
Another way of classifying electronic injection
modified by the ECU depending on the temperature
systems is according to the strategy used by the
of the air admitted, that is, depending on its density.
Electronic Control Unit (ECU) to calculate the base
Two examples of Electronic Control Modules that
injection time, as we can see in Figure 6. Thus,
use this strategy are:
systems can be classified:
* BOSCH LE-JETRONIC / L3.1 JETRONIC:
Electronic Control Modules that use this
 Classification of Automotive Injection Systems

Injection strategy managed by the Electronic Control Module (ECO) in a Sequence Invection
System!

- 1 cumulative injection Number of injections

- 2 cumulative injections accumulated at the moment
Indica - 3 cumulative injections Indica that the intake valve of the
#*** - 4 "cumulative" injections cylinder opens

CYLINDERS Engine cycle OPERATION

condition FROM THE
1 2 3 4
compression expansion admission discharge ENGINE
Start of cycle (rotee1-
*
inj * * # ARRANOUE injects
expansion discharge understanding admission simultaneously into all
180°to360• cylinders 2 times per elbow
** #* *1 **
qn/inj in the decigenal turn
discharge admission expansion compression
360° to
iun/iny #** #** #* * and
ign inj. 1
admission compression discharge expansion End of cycle 540° NORMAL
**** % ** *
Once the ECU identifies the
understanding expansion admission discharge
Start of the cycle cylinders in the intake

inj. 1 a #** # 0° to 180° manifold, the

injection
expansion discharge comp injury admission
begins to
itn 180-to-360-
inj, 4 and «« be realized
discharge Atmmission expansion comps sion sequentially only in the
380° to
cylinder that is in the
ig inj. 2 * % admission phase
admission compression discharge expansion
inj. ign. 1 End of cycle 540°

%
with pressure expansion admission discharge
ign inj. 3 Start of cycle 0 to 180•

a *

ign inj. 4 expansion discharge compression admission

180-to-360-
and #
Indicates I w ■ Ignition of the "m-“L Air/Gasoline mixture
Table 3
strategy but apart from modifying the Base Injection By the Position that the Butterfly
Time based on the temperature of the air admitted, Takes Depending on the Engine RPM
they also modify it based on the information from the
Oxygen Probe (probe _), by having this sensor. The Electronic Control Module has a “Time Table”
* BOSCH MOTRONIC M1.5.1 / M1.5.2 / stored in its memory.
M1.7.2 / M1.7 “Injection Basics” based on these two parameters.
During engine operation, it analyzes the
Technical Manuals

information received from the respective sensors, * MULTEC - 700 / EMS EFI / EMS MPFI /
TPS and RPM and TDC sensor. With this data and IEFI 6
based on its program, it performs the corresponding * DIGIFANT - 1.74 / 1.82
calculation and consults the table recorded in its * SAGEM - S 2000 / SL 96
memory, thus determining the Basic Injection Time * SIEMENS - Sirius 32
corresponding to each engine condition.
The Basic Injection Time is modified based on the
engine temperature, intake air temperature, and By Air Mass
information from the oxygen sensor (probe).
The Electronic Control Module has stored in its
An example of an Electronic Control Module that
memory a Basic Injection Time Table based directly
uses this strategy is:
on the Mass of Air Admitted.
* BOSCH M 1.2.3 / MA 1.7 / MA 3.0 / MP 3.2 The Mass of Air that is being admitted at any
given time by the engine is reported to the ECU by
the MAF (mass air flow meter). According to the
By the Density of Admitted Air information received, she searches her memory for
x the Engine RPM the Base Opening Time that she should apply to the
injectors.
The Electronic Control Module has stored in its The Basic Injection Time is modified based on the
memory a Basic Injection Time Table based on these engine temperature, the intake air temperature, the
two parameters. During engine operation, the ECU position of the TPS butterfly valve, the EGR (exhaust
analyses the information received from the respective gas recirculation), the battery voltage, and information
sensors, MAP (Intake Manifold Absolute Pressure from the oxygen sensor (lambda probe).
Gauge) and from the Air Temperature Sensor. With Some examples of Electronic Control Modules
this data and based on your program, you perform the that use this strategy are:
corresponding calculation and determine the Density
of the Inhaled Air. * BOSCH Motronic - 1.5.2 / M 2.8 / M 2.9 / M
With this result and the engine RPM the ECU 2.7 / M 2.10.4 / M 3.8.2 / 3 / ME 7.5
performs a new calculation: * HITACHI - M 159 MPI
* SIEMENS - Simos 2.1 / 4S / MS 41.1
Density of Intake Air x RPM x VE =
= Volumetric efficiency of the cylinder Remember that the fuel, through the action of the
Fuel Pump and the Fuel Pressure Regulator, must
With the result of this new calculation, look in the reach the Injectors with Constant Pressure and Flow
table recorded in your memory for the Basic Injection for all engine operating conditions. This allows the
Time corresponding to each engine condition. amount of fuel injected at any given time to depend
The Basic Injection Time is modified based on the exclusively on the time the injector remains open.
engine temperature, the position of the TPS butterfly
valve, the EGR (exhaust gas recirculation), the
battery voltage and the information from the oxygen EXAMPLES OF SYSTEMS IN
sensor (probe). COMMERCIAL VEHICLES

Some examples of Electronic Control Modules

Below are some examples of fuel pressures in
that use this strategy are:
different “Single Point” and “Multi Point
Simultaneous / Semi Sequential / Sequential”
* BOSCH Motronic - M 1.5.4 / ME 7.3H4 /
injection systems, taking models marketed in Latin
MP 5.2 / MP 5.1.1 / ME 7.9.6
America.
* FIC EEC IV - CFI / EFI
* MAGNETI MARELLI - G7 / G7.11 / IAW
49F / IAW 5NF / IAW 1ABW / IAW 1AB
 Classification of Automotive Injection Systems

FIAT - Fiorino Engine 1.0 ie - 8V - 1996: FORD - Fiesta Motor 1.3 - 1996:
Magneti Marelli IAW G7.11 System - Single point EEC IV CFI System - Single point injection.
injection. o Fuel pressure: 1.0 bar - pressure regulator on
o Fuel pressure: 1.0 bar - pressure regulator on the throttle body.
the throttle body. o Fuel pump flow rate: 60 l/h (submerged in the
o Fuel pump flow rate: 90 l/h (submerged in fuel fuel tank).
tank)
FORD - Escort Engine 1.6 - 2002:
FIAT - Type Engine 1.6 ie - 1995: EEC IV EFI System - Sequential multipoint
Bosch Monomotronic MA 1.7 system - Single injection.
point injection. o Fuel pressure: 3.0 bar - pressure regulator, in
o Fuel pressure: 1.0 bar - pressure regulator, on the fuel tank at the pump outlet.
the throttle body. o Fuel pump flow rate: 105 l/h (submerged in the
o Fuel pump flow rate: 100 l/h (submerged in the fuel tank).
fuel tank).
General Motors (GM) -
FIAT - Fiorino Motor Fire 1.3 8V - 2003: Corsa Engine 1.0 EFI - 1995:
Magneti Marelli 4AF System - Sequential multi- Multec TBI System - Single point injection and
point injection. similar.
o Fuel pressure: 3.0 bar - pressure regulator, in o Fuel pressure: 1.0 bar - pressure regulator on
the fuel tank at the pump outlet. the throttle body.
o Fuel pump flow rate: 100 l/h (submerged in the o Fuel pump flow rate: 80 l/h (submerged in fuel
fuel tank). tank)

FIAT - Palio Motor 1.5 - 2004: GM - Corsa Engine 1.0 MPFI - 2002:
Magneti Marelli IAW 1G7 System - Semi- Multec IEFI System - 6 - Semi-sequential
sequential multipoint injection. multipoint injection.
o Fuel pressure: 2.6 bar with vacuum connected - o Fuel pressure: 1.0 bar - pressure regulator on
3.0 bar without vacuum connected (pressure the throttle body.
regulator on the injector rail).
o Fuel pump flow rate: 80 l/h (submerged in the
o Fuel pump flow rate: 100 l/h (submerged in the fuel tank).
fuel tank). GM- Meriva Engine 1.8 16V - 2005:
FIAT - Palio Motor Fire 1.0 16V - 2003: Multec H System - Sequential multipoint injection.
Bosch Motronic ME 7.3 H4 system - Sequential o Fuel pressure: 3.0 bar - pressure regulator on
multipoint injection. the injector rail.
o Fuel pressure: 3.0 bar - pressure regulator, in o Fuel pump flow rate: 100 l/h (submerged in the
the fuel tank at the pump outlet. fuel tank).
o Fuel pump flow rate: 100 l/h (submerged in the
fuel tank). GM - Astra Engine 2.0 16V - 2005:
Bosch Motronic 1.5.5 system - Sequential
FORD - Escort Engine 1.6 - 1996: multipoint injection.
EEC IV EFI system - Single point injection. o Fuel pressure: 2.8 bar - pressure regulator, in
o Fuel pressure: 1.0 bar - pressure regulator on the fuel tank at the pump outlet. .
the throttle body. o Fuel pump flow rate: 100 l/h (submerged in the
o Fuel pump flow rate: 100 l/h (submerged in fuel fuel tank).
tank)
GM - Vectra-B Engine 2.0 8V - 2005:
Bosch Motronic 1.5.4 system - Sequential
Technical Manuals

multipoint injection. o Fuel pressure: 3.0 bar - pressure regulator, in

o Fuel pressure: 3.0 bar - pressure regulator on the fuel tank at the pump outlet
the injector rail. o Fuel pump flow rate: 100 l/h (submerged in the
o Fuel pump flow rate: 100 l/h (submerged in the fuel tank).
fuel tank).
RENAULT - Laguna Motor 2.0 16V - 2000:
PEUGEOT - 106 Engine 1.0 - 2001: Siemens Fenix 5 System - Sequential multi-point
Bosch Mono Motronic MA 3.1 system - Single injection.
point injection. o Fuel pressure: 3.0 bar - pressure regulator on
o Fuel pressure: 1.0 bar - pressure regulator on the injector rail.
the throttle body. o Fuel pump flow rate: 100 l/h (submerged in the
o Fuel pump flow rate: 90 l/h (external to fuel fuel tank).
tank).
RENAULT - Megane Engine 1.4 16V - 2006:
PEUGEOT - 406 SW Engine 1.8 16V - 2004: Siemens Sirius 32 System - Sequential multi-point
Magneti Marelli IAW 1AP System - Semi- injection.
sequential multi-point injection. o Fuel pressure: 3.0 bar - pressure regulator, in
o Fuel pressure: 2.8 bar - pressure regulator on the fuel tank at the pump outlet.
the injector rail. o Fuel pump flow rate: 100 l/h (submerged in the
o Fuel pump flow rate: 90 l/h (external to fuel fuel tank).
tank).
VOLKSWAGEM (VW) -
PEUGEOT - 306 SW Engine 1.8 16V - 2004: Gol Engine 1.0 MI 16V - 2005:
Magneti Marelli IAW 8P System - Simultaneous Magneti Marelli 4LV / 4SV / 4MV System -
multi-point injection. Sequential multi-point injection.
o Fuel pressure: 2.8 bar - pressure regulator on
the injector rail.

o Fuel pump flow rate: 90 l/h (external to fuel

tank).
PEUGEOT - 206 SW Engine 1.0 16V - 2006:
Magneti Marelli IAW 5NP System - Sequential
multipoint injection.
o Fuel pressure: 2.8 bar - pressure regulator on
the injector rail.
o Fuel pump flow rate: 90 l/h (external to fuel
tank).

RENAULT - 19 Engine 1.6 - 1999:

Bosch Mono Motronic MA 1.7 System -
Single point injection
o Fuel pressure: 1.0 bar - pressure regulator on
the throttle body.
o Fuel pump flow rate: 100 l/h (submerged in fuel
tank)

RENAULT - Kangoo Engine 1.6 8V - 2003:

Siemens Sirius 32 System - Sequential multi-point
injection.
 Classification of Automotive Injection Systems

o Fuel pump flow rate: 100 l/h (submerged in the VW - Golf GTI Engine 2.0 - 1998:
fuel tank). Digifant System - Simultaneous multi-point
o Fuel pressure: 3.0 bar - pressure regulator, in injection.
the fuel tank at the pump outlet. o Fuel pressure: 3.2 bar - pressure regulator on
the injector rail.
VW - Gol Motor 1.0 MI 8V - 2005: o Fuel pump flow: 100 l/h.
Bosch Motronic MP 9.0 System - Sequential multi-
point injection. The data given here are just some examples;
o Fuel pressure: 3.0 bar - pressure regulator, in more information can be obtained from the CD that
the fuel tank at the pump outlet. accompanies this work and can be downloaded from
o Fuel pump flow rate: 90 l/h (submerged in the the Internet.
fuel tank).

VW - Gol Engine 1.8 MY - 2005: ELECTRICAL PULSES SEEN WITH THE

Magneti Marelli 1AVP System - Sequential multi- OSCILLOSCOPE IN THE DIFFERENT
INJECTION SYSTEMS
point injection.
o Fuel pressure: 3.0 bar - pressure regulator on In volume No. 84 of the Club Saber Electrónica
the injector rail. collection, Mexican edition, published a few months
o Fuel pump flow rate: 90 l/h (submerged in the ago, we explained the use of the multimeter and the
fuel tank). oscilloscope in the automobile. This book explains
what an oscilloscope is, what types exist and how it is
VW - Polo Engine 2.0 - 2002:
used to locate faults and tune different systems in a
Bosch ME 7.5.10 System - Sequential multi-point
car.
injection
o Fuel pressure: 3.0 bar - pressure regulator, in The oscilloscope is a measuring device capable of
the fuel tank at the pump outlet. displaying in graphs all the electrical measurements
o Fuel pump flow rate: 90 l/h (submerged in fuel that are made with a multimeter, as well as others
tank) that, due to the speed with which they change value,
cannot be measured with a tester or multimeter.
There are laboratory oscilloscopes that include
many controls and adjustments, some of which are
not used in the automotive industry, so the most
suitable for automobiles are portable digital
oscilloscopes, specific for automotive use, or also
those that are used with a computer by means of
software that is installed and an interface or
element that is placed between the computer and
the circuit to be measured. In general, there are
three types of oscilloscopes:
 Technical Manuals

o Laboratory analog oscilloscope.

o Portable digital automotive
oscilloscope.
o Digital oscilloscope integrated
into PC, which can be 2 or 4
channels.

Some display at least 2 channels

simultaneously, which is an
advantage when comparing signals
that are related to each other.

Bosch Single Point System

Monotronica MA 1.7

In figure 7 we can see the ECU

circuit in the environment of the
injection system, where: As its temperature rises, the injection time and RPM
decrease until reaching normal speed. Figure 8
either Injector resistance: 2 ohm shows the injection pulse waveform, taken at terminal
either Ballast resistance: 3 ohm 35 of the ECU.
This injection system was also used in a Renault
Because the system uses an injector whose 19 1.6 model - Year 1997 to 1999.
winding has a low resistance, around 2 ohm, a
resistor is placed in series with it to limit the maximum
current intensity that can flow. Magneti Marelli G7.11 Mono Point System
This resistance is called “Resistance
“Ballast” and its value is around 3 ohm. This Figure 9 shows the ECU circuit.
constructed with special wire wound
around a cylindrical porcelain shape and
encapsulated with this material.
The ballast resistor is usually mounted in
the engine compartment on the fire wall.
Below the circuit is shown the injection
pulse imposed by the ECU, seen on the
screen of an oscilloscope.
The injection time is within the normal
operating limits of the engine. Normally in a
single point system this time varies
between: 1.7 ms to 2.4 ms depending on the
conditions required of the engine, its
temperature, etc. At start-up and with a
cold engine, the injection time can reach 10
ms or more, the engine starts with a speed of
approximately 1500 RPM and as
 Classification of Automotive Injection Systems

Pmiilluitue

Figure 10

Pulse of

Peugeot 306 1.6/405 1.8 Figure 11

Double relay

■ pu
ECU
Bosch AECP
Motion re
MP 5.1
EFE ignition
coils

Cyl.1 Cyl.2 Cyl.3 Cyl.4

1nyp dores

• to the IAC valve

3 the heating resistance of the Lambda

Probe

Ozrillnscope

Figure 12

Injection pulse seen with oscilloscopeCHA

connected 3 any injector 0 to Pin 17 of the ECU
Technical Manuals

in the injection system environment, where: o Injector

resistance: 2 ohm

This system also uses an injector whose winding has

a low resistance, around 2 ohm, but instead of
inserting a resistor in series with the injector to limit
the maximum current that can flow through it, this
system uses an ECU strategy to achieve this
limitation.
The injection pulse is made up of a base pulse and is
completed with a series of successive pulses of short
duration, the number of which depends on the total
injection time that the ECU must impose.
This pulse can be seen in the graph in figure 10; in
that case the oscilloscope is connected to terminal 18
of the ECU (see figure 9 again). In this way the
average current circulating through the injector is
limited to a preset maximum.
During the pulses, the time in which the injector
remains deactivated is not long enough for it to close
due to its magnetic and mechanical inertia.
Below the circuit is shown the injection pulse imposed
by the ECU, seen on the screen of an oscilloscope.
The injection time is within the normal operating limits
of the engine, between 1.7 ms and 2.4 ms depending
on the conditions required of the engine, its -
temperature, etc.
When starting and with a cold engine, the injection
time can reach 10 ms or more, the engine starts with
a speed of approximately 1500 RPM and as its
temperature rises, the injection time and RPM
decrease until reaching the normal speed.
 Classification of Automotive Injection Systems

Multi-Point System, Simultaneous

Injection Bosch Motronic 5.1

Figure 11 shows the ECU circuit in

the area around the injection system and
Figure 12 shows the injection pulse
imposed by the ECU, seen on the screen
of an oscilloscope (note that the
oscilloscope is connected to terminal 17
of the ECU connector).
The resistance of the injector coil is
14 ohm. Note in the circuit that these are
arranged in parallel connection, hence
the name Simultaneous Injection,
because every time the ECU grounds its
Pin 17 all the injectors are activated at
the same time.
The injection time during starting and
with a cold engine can be between 5 to 8
ms, depending on the engine
temperature. This will start and run at
about 1300 RPM and as the engine
temperature increases the injection time
will decrease as well as the RPM.
When the engine reaches normal
operating temperature, the idle speed will
remain at 850 to 900 RPM and the
injection time will be 1.7 to 1.9 ms.

Multi-point injection
Semi Sequential EEC-IV

Figure 13 shows the ECU circuit in

the environment of the EEC-IV Semi-
Sequential Multi-Point injection system of
a Ford Orion 2.0.

o The resistance of the injector coil is

14 ohm.

Figure 14 shows the injection pulses

arranged by the ECU in the
Injection pulses at start-up seen with an oscilloscope (300 RPM approx.)

CHA-tip dim >10 connected to injector 1 or 4 or to Pm 58 of

the ECU
CHB Settings - Dimmed tip x 10 connected to injector 2030 to ECU scope
Pin59
Time Base 100ms/di Vertical Gain' 2 V'dN.
Trigger source: CHA Siope:=
Technical Manuals

semi-sequential system proposed when

the engine is in the starting phase. Note
that since the injectors corresponding to
cylinders 1 and 4 are in parallel, when
the ECU grounds its Pin 58, both
injectors are activated at the same time.
The same happens with the injectors
corresponding to cylinders 2 and 3, they
are activated at the same time when the
ECU grounds its Pin 59. At start-up, the
ECU grounds its Pins 58 and 59
simultaneously, which is why the
injection pulses are in phase.
The top trace (yellow) in Figure 14
shows the oscilloscope signal on
injectors 1 and 4 while the bottom trace
(green) shows the oscilloscope signal on
injectors 2 and 3.
When the engine starts, the ECU has
already identified each pair of cylinders
on its upstroke, cylinders 1 and 4 and 2
and 3. It, based on the program in its
memory, changes the injection strategy
and alternately activates, every 180º of
crankshaft rotation, two injectors at a
time, injectors corresponding to
cylinders 1 and 4 and after half a
crankshaft rotation, those corresponding
to cylinders 2 and 3. The top trace
(yellow) in Figure 15 shows the
oscilloscope signal on injectors 1 and 4
while the bottom trace (green) shows the
oscilloscope signal on injectors 2 and 3.

Multec H Sequential Multipoint

Injection

Figure 16 reproduces the ECU circuit in

the environment of the injection system
of a Corsa C 1.8 with sequential
multipoint system.
Figure 17 shows the injection pulses
arranged by the ECU.
 Classification of Automotive Injection Systems

in the proposed sequential system, when

the engine is in the starting phase.
Note that in this engine condition, the
ECU activates all the injectors at the same
time, grounding their Pins B09; B22; B08
and B11 in unison, which is why the signals
appear in phase. Once the engine starts,
the ECU has already identified in which
crankshaft position each cylinder is in the
intake phase. It achieves this through the
information it receives from the phonic
wheel and the phase sensor (some ECUs
do not use a phase sensor, the crankshaft
position is identified by software) and
based on its program it changes the
strategy, ordering the opening of the
injector corresponding to the cylinder that,
in the intake phase, is mechanically
opening its intake valve. The injection
sequence follows the same order as the
ignition, Cyl.1; Cyl. 3; Cyl. 4; Cyl. 2.
The fuel dosing achieved with this
system is much more precise than in the
two systems described above. Figure 18
shows the injection pulses arranged by the
ECU in the proposed sequential system,
when the engine is running at 2000 RPM.
In this figure, each signal represents the
following:

o Upper trace (yellow) of the

oscilloscope on the Cylinder 1 Injector.
o Second trace (green) of the
oscilloscope on the Cylinder 2 Injector.
o Third trace (blue) of the oscilloscope
on the Cylinder 3 Injector.
o Last trace (red) of the oscilloscope on
the Cylinder 4 Injector.

Note: The circuits included are only a

part of the complete wiring of the ECU that
manages the injection and ignition in the
different systems taken as an example. The
complete circuit is not included for space
reasons. J
 - help of electronics to deliver fuel injection and reduce the

electronic
injection
Electronic injection is a
form of fuel dosing, both
in the car
emission of polluting agents into the atmosphere and, at the
same time, optimize the consumption and performance of the
for gasoline engines, in vehicle. This system has replaced the carburettor in gasoline
which it has been engines. Its introduction was due to an increase in the demands
implemented for several of environmental control agencies to reduce engine emissions.
decades, and for diesel In diesel engines, the injection pump, which has mechanical
engines, whose injectors, has been replaced by a high-pressure pump with
introduction is relatively electrohydraulic injectors.
more recent. It can be In this Educational Package you will find a wealth of
subdivided into several information on both injection systems and automotive on-board
types (single point,
multipoint, sequential, simultaneous, etc.) and is based on the
diagnostics. J

Contents of this educational package CD

Module 1: Electronics in the Car Chapter 1: How a Air Flow Sensor: Air Flow Meter Data structure
Car Engine Starts Throat position sensor Scanner with the ELM327
Electric motor start Crankshaft position sensor The CAN BUS system
The electric motor Manifold absolute pressure sensor Description of an OBDII interface Part 4 Conclusion
The starter motor coupling mechanism Oxygen sensor Using a scanner
Common starter motor failures.. Water temperature sensor Sensors and Actuators
STARTER MOTOR DIAGNOSIS Auxiliary air regulator Protocol Selection
Operation of the starter motor Control of revolutions at rest
Programming a scanner
A common fault EGR: Exhaust gas recirculation valve.
Bus monitoring
OPERATION AND BASIC TESTS OF THE PCV: Positive crankcase ventilation
CAN System Features
ALTERNATOR Crankshaft position sensor
Electronic circuits for cars
Alternator Test SINGLE POINT AND MULTIPOINT SYSTEMS
Classification of injection systems Description of an OBDII 2 interface.
Coil and winding tester
Chapter 2: Hybrid Vehicles Depending on where they inject Microcontrolled on-board computer
The birth of hybrids According to the number of injectors How to start the engine
Electric motor According to the operating characteristics ABS
Electric generator Multipoint injection systems: Jetronic and Motronic Starter Motor Diagnosis
Series connection and parallel connection Single-point injection system: Mono-Motronic and Much More...
Electric vehicle Chapter 5: On-Board Diagnostics oBd i and oBd ii
Vehicle with electric motor Some OBD codes Module 4: Programs and Applications
Gasoline powered vehicle COMPONENTS OF AN OBD II SYSTEM In this module you will find a link that will allow
Series hybrid vehicle SOME OBD II SCANNERS you to download from our website a series of
Parallel hybrid vehicle A simple interpreter: OBD or USB interface very useful programs and applications, whose
Ultralight hybrid vehicle Optocoupled OBD II interface description and operation were developed in the
PARALLEL CONFIGURATION ODBII interface for BMW theoretical module. We remind you that you
Are hybrid vehicles dangerous for health? must have Internet access. Some of the
Module 2: Books “Automobile Electronics”
TOYOTA AND HONDA HYBRID VEHICLES programs and applications are:
Volume 1: Automotive Electronics
The Honda “Insight” Virtual OBD II Scanner for your PC
Volume 2: OBD II
Honda Prius Software instructions
Volume 3: Design and Construction of OBD II Scanners
Chapter 3: Direct Gasoline Injection Engines Volume 4: Electronic Circuits in the Automobile USB Driver
Two modes of combustion Volume 5: Using the Multimeter and Oscilloscope ELM 327 User Guide
Precise control of the Air/Fuel mixture. in Car Repair EasyOBDII
The efficiency of using fuel better Volume 6: Electronic Injection Systems WOBDCRAZY
General scheme of operation Volume 7: Electronic Measurements in the Automobile 1 ScanMaster-ELM
The vertical intake manifold Volume 8: Electronic Measurements in the Automobile 2 Scantool_net113win
Stratified mixture OBD2Spy
Chapter 4: Electronic injection in the automobile Module 3: More recommended theory And Much More…
Differences between carburetor system and In this module you will find a series of very
electronic injection useful notes regarding automotive electronics Module 5: videos
TBI: Throttle Body Injection or CFI: Central Fuel in general. Below is the complete list: In this module we place video clips explaining
Injection More sensors and actuators the installation of an interface with the ELM327,
Fuel injection, operating principles Reading the battery voltage and the scanning of a vehicle as a
SENSORS AND ACTUATORS SCAN MASTER Management
demonstration.
Cold Star Val: Cold Start Valve Electronic fuel injection in the automobile
Temperature sensor Command interpretation Module 6: Electronic injection
Air Mass Sensor: Air Mass Meter Liquefied gas Classification of Automotive Injection Systems
Hybrid Operation Bosch Electronic Injection Systems