2.
1 Internal Combustion
Engines
Module – 2
2.1 Internal Combustion Engines: Engine
types and configurations, Thermodynamics of
ICE, Fuel types and emissions
-4
2.2 Alternative Power train: Electric and
hybrid vehicles, Battery technology and
management systems, Fuel cell technology
-4
Introduction:
✓An internal combustion engine (ICE) is a type of
engine where fuel is burned inside the engine's
cylinders to produce power.
✓This combustion process generates high-temperature
and high-pressure gases that push against engine
components, typically pistons, to create mechanical
work.
TYPS OF I.C.ENGINE
Classification of I.C. Engines
(i) According to the type of fuel used
(a) Petrol engines: In this type of engines, the fuel used is petrol.
(b) Diesel engines: In this type of engines, the fuel used is diesel.
(c) Gas engines: In this type of engines, the gaseous fuels like natural gas, biogas, are used.
(d) Bi-fuel engines: These engines use a mixture of two fuels.
(ii) According to the number of strokes per cycle
(a) 4-stroke engine: In this type of engines, the working cycle is completed in four different
strokes.
(b) 2-stroke engine: In this type of engines, the working cycle is completed in two different
strokes.
(iii) According to the method of ignition
(a) Spark ignition engine (S.I.Engine):In this type of engines, fuel is ignited by an electric
spark generated by a spark plug.
(b)Compression ignition engine (C.I. Engine):In this type of engines, the fuel gets ignited as
it comes in contact with the hot compressed air.
Classification of I.C. Engines
iv)According to the cycle of combustion
(a)Otto cycle engine: In this type of engines, combustion of fuel
takes place at constant volume
(b)Diesel cycle engine: In this type of engines, combustion of fuel
takes place at constant pressure
(c) Duel combustion engine: In this type of engines, combustion of
fuel first takes place at constant volume and then at constant
pressure.
(v) According to the number of cylinders
(a) Single cylinder engine: This type of engines consists of only
one cylinder.
(b) Multi cylinder engine: This type of engines consists of 2, 3, 4,
6 or 8 cylinders.
Classification of I.C. Engines
(vi) According to the arrangement of cylinders
(a) Vertical engine: In this type of engines, the cylinder is arranged in a vertical
position
(b) Horizontal engine: In this type of engines, cylinder is arranged in horizontal
position.
(c) Inline engine: In this type of engines, cylinders are arranged in line
(d) Radial engine: In this type of engines, cylinders are arranged along the
circumference of a circle.
(e) V-engine:In this type of engines, combination of two inline engines equally
set an angle.
(vii) According to the method of cooling
(a) Air cooled engine:In this type of engines, the heated cylinder walls are
cooled by continuous flow of air
(b) Water cooled engine:In this type of engines, water is used for cooling the
heated cylinder walls.
Basic components of IC engines
Configurations of I.C. Engine
Internal combustion (I.C.) engines come in various configurations, each with distinct
characteristics suited for different applications. Here are some of the most common
configurations:
1. Inline Engine
▪ Description: Cylinders arranged in a straight line.
▪ Common Types: Inline-3, Inline-4, Inline-5, Inline-6.
Advantages: Simple design, compact size, and smooth operation.
2. V Engine
▪ Description: Cylinders arranged in a V-shape.
▪ Common Types: V6, V8, V10, V12.
▪ Advantages: More power in a compact space, balanced operation, often used in performance and luxury vehicles.
3. Flat Engine (Boxer Engine)
▪ Description: Horizontally opposed cylinders.
▪ Common Types: Flat-4, Flat-6.
▪ Advantages: Low center of gravity, good balance, and reduced vibration.
4. Rotary Engine (Wankel Engine)
▪ Description: Uses a triangular rotor instead of cylinders.
▪ Advantages: Fewer moving parts, compact size, and high power-to-weight ratio.
5. Radial Engine
▪ Description: Cylinders arranged in a circular pattern around a central crankshaft.
▪ Common Applications: Primarily used in aviation.
▪ Advantages: Lightweight and powerful for aircraft.
6. Dual-Cylinder Engine
▪ Description: Two cylinders, can be arranged inline
or in a V configuration.
▪ Common Applications: Small motorcycles and
some cars.
▪ Advantages: Simple, lightweight, and cost-effective.
7. Multi-Cylinder Engine
▪ Description: More than two cylinders, can be
configured in various ways (inline, V, flat).
▪ Advantages: Increased power output, smoother
operation, and improved efficiency.
Thermodynamics of IC engine
• Most I.C. engines operate on specific
thermodynamic cycles. The two most common
are:
• Otto Cycle: Used in gasoline engines.
• Diesel Cycle: Used in diesel engines
Fuel types and emissions
Internal combustion (I.C.) engines can operate on various fuel types, each with its own emission
profiles and environmental impacts. Here's an overview of common fuel types and their associated
emissions:
1. Gasoline
Characteristics: A widely used fuel in spark-ignition engines.
Emissions:
▪ CO2: Carbon dioxide, a greenhouse gas.
▪ CO: Carbon monoxide, a toxic gas produced from incomplete combustion.
▪ NOx: Nitrogen oxides, contributing to smog and respiratory issues.
▪ HC: Unburned hydrocarbons, which can lead to ozone formation.
2. Diesel
Characteristics: Used in compression-ignition engines, diesel fuel has a higher energy density than
gasoline.
Emissions:
▪ CO2: Lower per energy unit than gasoline but overall emissions can be higher due to higher
fuel consumption.
▪ NOx: Generally higher than gasoline, contributing to air pollution.
▪ PM: Particulate matter, which can cause serious health problems.
▪ HC: Unburned hydrocarbons, though usually lower than in gasoline engines.
3. Ethanol
Characteristics: A biofuel often blended with gasoline (e.g., E10, E85).
Emissions:
▪ CO2: Generally lower emissions since it's derived from renewable sources.
▪ CO: Can be higher than gasoline in certain conditions.
▪ NOx: Similar or slightly lower than gasoline.
▪ HC: Varies based on blend and combustion efficiency.
4. Biodiesel
Characteristics: Derived from vegetable oils or animal fats, used in diesel engines.
Emissions:
▪ CO2: Lower net emissions due to the renewable nature of feedstocks.
▪ NOx: Can be higher than traditional diesel.
▪ PM: Generally lower, but quality varies.
▪ HC: Can be similar to or lower than conventional diesel.
5. Natural Gas
Characteristics: Primarily methane, used in both dedicated and dual-fuel I.C. engines.
Emissions:
▪ CO2: Lower than gasoline and diesel per energy unit.
▪ NOx: Lower than diesel but can be similar to gasoline depending on combustion conditions.
▪ CO: Generally lower.
▪ PM: Very low, making it a cleaner option.
6. Hydrogen
Characteristics: Used in fuel cells or modified I.C.
engines.
Emissions:
▪ CO2: Zero emissions at the point of use.
▪ NOx: Can be produced at high combustion temperatures.
▪ CO and HC: Very low or negligible.
7. Propane (LPG)
Characteristics: A byproduct of natural gas processing
and petroleum refining.
Emissions:
▪ CO2: Lower than gasoline and diesel.
▪ NOx: Lower than gasoline and diesel.
▪ CO: Generally lower.
▪ PM: Very low.
