eBook Automotive Technology

DEPARTMENT OF MECHANICAL ENGINEERING

AUTOMOTIVE TECHNOLOGY

All rights reserved. No part of this publication may be reproduced, used
for editing or stored in a retrieval system, or transmitted, in any forms or by

any means, electronic, mechanical, photocopying or otherwise without
obtaining written permission from Department of Polytechnic Education,

Ministry of Higher Education.

Writer:
Ahmad Taufiq Wafi bin Abd Ghani

Ab Hakim bin Ab Halim
Mohd Fikri bin Mohd Soffian

Published by:
Politeknik Port Dickson,
Department of Mechanical Engineering,
KM 14, Jalan Pantai,

71050 Si Rusa,
Negeri Sembilan.

First Edition 2021

eBook on Automotive Technology Polytechnic Malaysia 2021 Edition

© Politeknik Port Dickson 2021

i

ACKNOWLEDGEMENT

In the name of Allah, the most Precious and the Almighty who gives us the
enlightenment, the truth, the knowledge and with regards to Prophet
Muhammad S.A.W. for guiding us to straight path. We thank to Allah S.W.T. for
giving us the strength to write this book. May Allah S.W.T. gives us the ability
to continue our good deeds to the community in this field.
This book is written to provide basic knowledge of automotive technology to
enables the students to embark on the study regarding three basic system.
This digital eBook contains three (3) chapters meet the course curriculum
that’s are Engine Management System, Forced Induction System and Emission
Control System.
It is important to understand the operation system in automotive technology.
The principals involved various type components, functions and operation in
the systems. We hope this book will be very useful as a guidance and
reference especially to Malaysian Polytechnic students and all parties
involved in implementation of automotive studies programme.

Ahmad Taufiq Wafi bin Abd Ghani
Ab Hakim bin Ab Halim

Mohd Fikri bin Mohd Soffian
POLITEKNIK PORT DICKSON

© Politeknik Port Dickson 2021

ii

ABSTACT

Automotive Technology is one of the course offered in Diploma of
Mechanical Engineering (Automotive) at Politeknik Malaysia. This course
provides knowledge on the concept and basic principles of three systems in
automotive technology, that are Engine Management System (EMS), Air
Induction System and Forced Induction System. It is hoped that students will
be able to understand and explain the evolving technology trends in
automotive systems with this digital material. The technique of compiling this
book is simple, concise and graphically informative. Each title is equipped
with sample questions and answers to facilitate the learning process. Today's
digital learning technology is one of the attraction for students to explore
knowledge without borders.

iii

TABLE OF CONTENTS

1.0 Engine Management System (EMS) 3
4
1.1 Development of engine control system 6
a. Types of engine management systems
b. Requirements and purpose of engine 8
management system
c. Function and component of Sub-system
of engine management system
i. Air induction system
ii. Fuel management system
iii. Control System/sensor system
d. Types, function and location of sensors
i. Oxygen sensor
ii. Air intake temperature sensor
iii. Engine temperature sensor
iv. Throttle position sensor
v. Air flow sensor
vi. Mass air flow sensor
vii. Crankshaft sensor
viii. Manifold pressure sensor
ix. Knock sensor
x. Engine oil sensor
xi. Engine speed sensor

iv

e. Types, function and location of actuators 27
i. Fuel injector
ii. Cold start injector 37
iii. Fuel pump 41
iv. Fuel filter
v. Fuel tank
vi. Fuel pressure regulator
vii. Pulsation damper
viii. Spark Plug
ix. Idling speed control valve
x. Radiator Fan

f. Type of fuel injection systems, its components
and its functions
i. Single point / throttle body injection
ii. Port or multipoint fuel injection
iii. Sequential fuel injection
iv. Direct Injection

Questions and Answers

v

2.0 Forced Induction System 46
50
2.1 Function, construction and operation of
forced induction system and its components 58
a. Forced induction system 61
b. Turbocharged system 62
i. Blow off valve
ii. Waste gate 66
iii. Intercooler
c. Supercharged system 72
d. Advantages and disadvantages of 73
turbocharger and supercharger
vi
Questions and Answers

3.0 Emission Control System

3.1 Types of vehicle emission sources
a. Exhaust emission pollutants and effects to
human health
i. Hydrocarbon, HC
ii. Carbon Monoxide, CO
iii. Oxide of nitrogen, NOx
iv. Particulate Matter, PM
v. Sulfur Oxide, SOx
b. The fuel evaporation sources
c. The “blow-by gas”

3.2 Explain the emission control systems 74
a. Types of emission control systems
i. Catalytic Converter 81
ii. Exhaust Gas Recirculation Systems, EGR 84
iii. Positive Crankcase Ventilation System, PCV 85
iv. Evaporative Emission Control System 86
b. The components name, function and
location
c. Overall layout of emission control
systems.
d. Secondary Air Injection System

Questions and Answers

vii

CHAPTER 1

ENGINE

MANAGEMENT

SYSTEM

(EMS)

1

OBJECTIVES

ENGINE MANAGEMENT SYSTEM

1 1) Types of engine management

2 2) Requirements and purpose of engine

management system

3) Function & component of Sub-system

3 of EMS
a. Air Induction System

b. Fuel Management System

c. Control system / sensor system

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saecntsuoartsors

5) Different type of fuel injection systems,

5 its components and its functions

a. Continuous Injection (K-Jetronic)
b. Multi Point Injection (L-Jetronic)
c. D-EFI Injection
d. Direct Injection

2

TYPE OF EMS

ENGINE MANAGEMENT SYSTEM

1
Non

Programmable EMS

•Most Engine Management System’s fitted to production vehicles are not
programmable, that is to say that the maps within the Engine Management
System which determine the fueling and ignition settings are fixed and
cannot be varied by the owner.
•This makes good sense from a manufacturers point of view since the engine
then runs within the permitted parameters which keeps the engine emissions
and economy within known limits.

2
Programmable EMS

•All after-market Engine Management System are programmable since they
have to be fitted to a variety of different engine installations in a variety of
states of tune.

•If the map values could not be changed then the EMS would be useless for
after market applications.
•Some manufacturers of these systems discourage home mapping and will
only allow authorized dealers to undertake the mapping.

Remap vs Retune ??

3

ENGINE MANAGEMENT SYSTEM (EMS)

•EMS – is a computer program which controls the running
of an engine by monitoring the engine speed, load,
temperature and providing the ignition spark at the right
time

•computer & electronics used to control the operation of
engines

•basic parts of an electric control system in Engine
Management System (EMS)

Sensor ECU Actuator

• An electronic device • Electronic board used • Receive the instruction
used to detects, to analyses & controls from ECU to do the
the data received by directed job.
collect data & send sensor and send the
instructions signal to • Mechanical device for
the data/signal to moving or controlling a
actuators mechanism or system
ECU
• It takes energy, usually
transported by air,
electric current, liquid &
converts that into some
kind of motion

4

ENGINE MANAGEMENT
SYSTEM OVERVIEW

ENGINE MANAGEMENT SYSTEM

How does an engine management system work? 5
Page 6

SUB SYSTEM EMS

AIR INDUCTION SYSTEM

• Supply the correct amount of air needed
to increase the combustion and the
efficiency of an engine.

• Delivery proper amount of air accurately
to all cylinders at proper time in the
engine.

• The 3 major components – blower,
turbocharger & supercharger.

How does an engine management system work?

An EMS is a self contained custom built computer which controls the running of an

engine by monitoring the engine speed, load and temperature and providing the

ignition spark at the right time for the prevailing conditions and metering the fuel to

the engine in the exact quantity required. 6

COMPONENTS

AIR FILTER
• To clean outside air before entering into the cylinder.
• The first part of an induction system components

AIR FILTER METER

• A mass (air) flow sensor (MAF) is used to find out
the mass flow rate of air entering a fuel-injected
internal combustion engine.

• The air mass information is necessary for the engine
control unit (ECU) to balance and deliver the correct
fuel mass to the engine.

THROTTLE BODY

• A throttle body is a butterfly valve located between the
air intake filter and the intake manifold.

• It regulates how much air can go into the engine, based
on driver input through the gas pedal.

• As more air flows into the engine, it injects more fuel, thus
allowing for more power.

• 2 types: by cable or by wire

VARIABLE INTAKE MANIFOLD

• Function: To optimize power and torque across the range
of engine speed operation, as well as help provide
better fuel efficiency.

• This effect is often achieved by having two separate
intake ports, each controlled by a valve, that open two
different manifolds:
• One with a short path that operates at full engine
load,
• Another with a significantly longer path that
operates at lower load.

INTAKE CHAMBER & MANIFOLD

7

HOTWIRE MAF SENSOR
VANE METER MAF SENSOR

8

THROTTLE BY CABLE

9

THROTTLE BY WIRE (DBW)

10

FUEL MANAGEMENT SYSTEM

• Assists the pilot in managing fuel by considering fuel flow, airspeed and winds

• Fuel supply are designed to deliver precision amounts of fuel as needed to
achieve the best balance between power, fuel economy, low exhaust emissions

• ECU receives the signals from related sensors and controls fuel injectors to
provide the best air-fuel ratio for various engine operating conditions

Fuel Delivery System 11

EFI COMPONENTS

1 FUEL TANK

• supply fuel to the system

2 FUEL PUMP
• deliver fuel from tank to system

3 FUEL FILTER
• filter the petrol/ fuel before entrance the

chamber

4 FUEL RAIL/DELIVERY

• connected fuel from tank to injector.

5 INJECTOR

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sensors

6 FUEL PRESSURE REGULATOR

• to maintain the fuel pressure in EFI system.

7 FUEL RETURN LINE

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sensors

12

AIR/FUEL RATIO

• A 'Stoichiometric' AFR has the correct

amount of air and fuel to produce a

chemically complete

combustion event.

• For gasoline engines, the
stoichiometric, A/F ratio is 14.7:1,
which means 14.7 parts of air to one
part of fuel.

Effect AFR
on Emission

• Air flow sensor 13
• Intake air temperature sensor
• Barometric pressure sensor
• ECT sensor
• Throttle position sensor
• Camshaft position sensor
• Crank angle sensor
• Ignition Switch – ST
• Detonation sensor
• Vehicle Speed sensor
• Oxygen sensor (vehicle with

catalytic converter)
• Mixture adjusting screw (vehicle

without catalytic converter

CONTROL/ SENSOR MANAGEMENT

• Detect operating condition system
• Send data & give information to EC

Computer to Requires Comprehensive
Function system
Properly
comprised of
various input &
output devices

TYPE OF SENSOR
1 OXYGEN SENSOR

2 AIR INTAKE TEMPERATURE SENSOR

14

3 CRANK ANGLE SENSOR
4 ENGINE TEMPERATURE SENSOR
5 MANIFOLD PRESSURE SENSOR
6 KNOCK SENSOR

15

7 ENGINE SPEED SENSOR
8 AIR FLOW SENSOR
9 THROTTLE POSITION SENSOR
10 ENGINE OIL SENSOR

16

1 OXYGEN SENSOR

To produce as few emissions as
possible & measures the air/fuel ratio

• The Oxygen Sensor detects the amount of oxygen in
the exhaust gas and sends a signal to the engine
control unit which adjusts the air fuel mixture to the
optimal level.

• Too much oxygen in the exhaust gas indicates a lean
mixture, which can cause performance problems,
including misfires.

• Too little oxygen indicates a rich mixture, which wastes

fuel and results in excess exhaust emissions. 17

2 AIR INTAKE TEMPERATURE SENSOR

Determine the correct engine fuel
requirement to suit the operating air

• This sensor is installed in the air intake tract. Together
with the signal from the manifold absolute pressure
sensor, its signal is applied in calculating the intake air
mass.

• Apart from this, desired values for the various control
loops can be adapted to the air temperature

18

3 CRANKSHAFT SENSOR (CKP)

Sends information of precise position &
speed of the crankshaft (information to

determine the relative positions of
pistons, belts & valves)

• The functional objective for the crankshaft position
sensor is to determine the position and/or rotational
speed (RPM) of the crank.

• The crank sensor can be used in combination with a

similar cam shaft position sensor to monitor the

relationship between the piston and valves in the

engine, which is particularly important in engines

with variable valve timing.

19

What are the symptoms of a bad or failing crankshaft position sensor?
Page 26

5 MANIFOLD PRESSURE
SENSOR (MAP)

Measuring the pressure in the intake
manifold relative to atmospheric
pressure

• The manifold absolute pressure (MAP) sensor provides
instantaneous manifold pressure information to the
engine's electronic control unit (ECU).

• The data is used to calculate air density and determine
the engine's air mass flow rate, which in turn determines
the required fuel metering for optimum combustion.

20

6 KNOCK SENSOR

Detects engine knock or detonation, which
then controls the timing of the engine -

caused when a spark plug does not ignite
the fuel properly

• knock sensors are basically vibration sensors and are
suitable for detecting structure-borne acoustic
oscillations.

• These occur as “knock” for instance in a vehicle's engine
when uncontrolled ignition takes place, and are
converted into electrical signals by the sensor and
inputted to the ECU

21

7 CRANKSHAFT SENSOR (CKP)

Sends information of precise position & speed
of the crankshaft (information to determine the

relative positions of pistons, belts & valves)

• The functional objective for the crankshaft position sensor is to
determine the position and/or rotational speed (RPM) of the
crank.

• The crank sensor can be used in combination with a
similar cam shaft position sensor to monitor the relationship
between the piston and valves in the engine, which is
particularly important in engines with variable valve timing.

22

8 MASS AIR FLOW SENSOR (MAF)

To measure the amount of air an engine takes
in engine load

• A mass air flow sensor is used to find out
the mass flowrate of air entering a fuel-injected internal
combustion engine.

• The air mass information is necessary for the engine
control unit (ECU) to balance and deliver the correct fuel
mass to the engine

• There are two common types of mass airflow sensors in use

on automotive engines. These are the vane meter and the

hot wire. 23

9 THROTTLE POSITION SENSOR

To tell the computer the position of the
throttle & helping the computer

determine if the throttle is closed or open
or how fast the throttle opened or closed

• A throttle position sensor (TPS) is a sensor used to
monitor the position of the throttle in an internal
combustion engine.

• The sensor is usually located on the butterfly spindle so
that it can directly monitor the position of the throttle
valve butterfly.

24

10 ENGINE OIL SENSOR

To measure engine oil temperature by
providing a resistance signal proportional

to the oil temperature

• This sensor is installed in the coolant circuit.
• The engine management system uses its signal when

calculating the engine temperature

25

The symptoms of a bad or failing crankshaft position sensor

1. Issues starting the vehicle
The crankshaft position sensor monitors the position and speed of the crankshaft
and other parameters that play an important role when starting the engine. If the
crankshaft position sensor is having a problem, the vehicle may have intermittent
starting issues or may not start at all.

2. Intermittent stalling
If the crankshaft position sensor or its wiring have any issues, it can cause the
crankshaft signal to be cut off while the engine is running, which can cause
the engine to stall.

3. Check Engine Light comes on
Another issue of a potential problem with the crankshaft position sensor is
an illuminated Check Engine Light. If the computer detects a problem with the
crankshaft position sensor’s signal, it will activate the Check Engine Light to alert
the driver of the problem. A Check Engine Light can also be set off by a wide
variety of other issues so having computer scanned for trouble codes is highly
recommended.

26

TYPE OF ACTUATOR

Fuel Thermostat Fuel Idle Speed
Pump Pressure Control
Regulator Valve

Fuel Spark
Injector Plug

Fuel Fuel Cold Radiator
Filter Tank Start Fan
Injector

SPARK PLUG

Spark plug has a copper center electrode core
surrounded by a nickel alloy, top of the plug. Inside
the plug, the center electrode is encased in porcelain,
which helps transfer heat from the engine to the
cooling system. Premium spark plugs make use of
precious metals, like platinum or iridium, in place of the
nickel alloy. Spark plug is to ignite the air and fuel
mixture inside the combustion chamber.

What are the common signs of faulty spark plugs include slow 27
acceleration, loss of power, poor fuel economy, engine misfires,
and difficulty starting the car.
Page 36

FUEL INJECTORS

PETROL INJECTOR

• For a gasoline engine, fuel pressure is
usually on the order of 35-50 psi.

• 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.

COMPRESSION RATIOS

The amount of fuel injected depends on
fuel pressure and injector pulse width time
Typical pulse width is 1 – 10 ms at full load
Primary factors are load and engine
temperature
Injector design and fuel additives help
reduce injector tip deposits and clogging

28

MAIN COMPONENTS …FUEL INJECTORS
PINTLE
MULTI-HOLE

29

…FUEL INJECTORS

PORT INJECTION

Intake valve Spark plug

Injector

FUNCTION OF FUEL INJECTOR

• nozzles that inject a spray of fuel into the
intake air

• when nozzle opened, fuel is spray into the
surrounding air

• the amount of fuel injected each cycle is
controlled by injector pressure & time
duration of injection

Dirty fuel injector symptoms? 30
Page 36

FUEL TANK

TYPE OF ACTUATOR

• Fuel tanks: Hold 45-75 liters
– Corrosive-resistant galvanized steel or plastic
– Baffle prevents fuel sloshing in tank
– Cluster assembly includes pickup tube, fuel gauge, fuel pump
– In-tank filter is installed at end of pickup tube
31

FUEL PUMP

• Fuel from pump flows in a fuel rail loop between engine and fuel tank
• Pressure regulator controls system pressure

• Electric fuel pump has one-way check valve that maintains pressure
when engine is off
• Submerged in well of fuel so cannot spark

• Fuel pump electrical circuit
• Electric fuel pumps on modern vehicles: computer controlled
• Remain on when engine is cranking or running

Electrical
connections

Fuel
lines

Electric Fuel gauge
fuel pump sending unit

Strainer

Float

Combination Electric Fuel Pump And Sending Unit.

32

FUEL FILTER

• Located in fuel line or tank
– Outlet filters: installed on outlet side
of fuel pump

• Fuel injection systems
– Require large, heavy-duty filters
• Filter out smaller particles of
dirt while allowing pump to
supply fuel

FUEL PRESSURE REGULATOR

• Located at end of fuel rail
• Maintains constant pressure at injectors
• Internal chamber contains a diaphragm

• Pressurized fuel on one side
• Manifold vacuum & spring tension on other
• Manifold vacuum pulls up on diaphragm, metering fuel that is returned to tank
• Excess fuel pressure can overcome spring tension, allowing fuel to return to tank
• Increases in manifold pressure causes spring tension to push diaphragm down,
blocking return line, increasing pressure in rail.

33

THERMOSTAT

• Thermostat regulates the temperature of water or
coolant in an engine.

• When the engine is cold, no coolant flows through
the engine.

• It helps the engine warm up to optimum operating
temperature which improves efficiency and emissions
output.

• Once the engine reaches its operating temperature
(generally about 200 degrees F, 95 degrees C),
the thermostat opens allowing the radiator to
remove heat from the coolant so it can be
circulated back into the engine.

• A thermostat is a normal
service item that when fails will
either stick closed making the
engine overheat quickly, or
stick open causing the engine
to warm up to slowly which will
trigger a check engine light.

Thermostat Operation

34

How to troubleshoot a faulty thermostat?

IDLE SPEED CONTROL VALVE (ISCV)

• An idle air control actuator or idle air control valve (IAC actuator/valve) is a
device commonly used in fuel-injected vehicles to control the engine's idling
RPM.

• In carbureted vehicles a similar device known as an idle speed
control actuator is used.

RADIATOR FAN

A cooling fan is a vital component in a car
cooling system, that helps takes away all heat
absorbed from the engine using coolant. All its
work is done through the radiator by pushing
or pulling air through the radiator. A radiator
cooling fan is located in front of a car and
it’s electrically powered, well, depending on
the vehicle design.

35

COMMON SIGNS OF FAULTY SPARK PLUGS

1. Slow acceleration. ...
2. Poor fuel economy. ...
3. Engine is misfiring. ...
4. Engine surging or hesitating. ...
5. Rough idle. ...
6. Hard to start.

DIRTY FUEL INJECTOR SYMPTOMS

1. The engine misfires. Dirty fuel injectors may cause
your vehicle's engine to misfire. ...

2. Idling gets rough. Does your vehicle sputter and
shake when you're at a stop sign or sitting in traffic?

3. Your gas mileage tanks.
4. The RPM needle starts to dance.
5. Your car won't start.

36

TYPE OF FUEL INJECTION SYSTEM

1 Continuous Injection
(K-Jetronic)

FUEL 2 Multipoint Injection
INJECTION
(L-Jetronic)
SYSTEM

3 Direct Injection

Continuous Injection Multipoint Injection Direct Injection
(K-Jetronic) (L-Jetronic)

Component Components Features

- Fuel Tank - Fuel Delivery System - Allows for very lean air/fuel
- Electric Fuel Pump mixtures
- Fuel Filter - Fuel Filter
- Fuel Pressure Regulator - Increases volumetric
- Fuel Pump - Fuel Injectors efficiency
- Cold Start Injector
- Accumulator – maintain - Fuel Accumulator - Uses very high fuel
rest pressure & reduced - Connecting Lines & Hoses pressures (typically between
noise created by 400 and 2000 psi)
pulsation of pressure
- System operates similarly
- Air Flow Sensor to diesel injection systems

Function Function 37

• mechanical-hydraulic • Multi-point systems use
and continuous fuel one injector per cylinder
injection (system indirect injection)

• Per cylinder, one • The amount of charge
injector-valve through between cylinders is
its own controller often closely regulated,
connected to fuel usually on a cycle-to-
regulator cycle basis

• sprays fuel through the • engine sensors &
injectors continuously. computer control the
opening & closing of
• Spray at minimal rate injection valve
to provide only what is
needed for each • injects fuel intermittently
cylinder to have the into the intake manifold
proper air-fuel ratio ports

TYPICAL GDI SYSTEM

OPERATIONAL MODES

• Lean Burn

• Can run as high

as 60:1

• Stoichiometric

• During medium

load

• Full Power

• During heavy

loads and hard

acceleration

HIGH PRESSURE FUEL PUMP

• Gas is delivered to the engine by an in-
tank pump

• A mechanical, high-pressure pump increases
fuel pressure to between 435 to 1885 psi

• Pressure regulated by input from fuel rail
pressure sensor

Stratified mode Homogeneous mode COMPRESSION RATIOS
• The ability to change air/fuel ratios

eliminates spark knock, allowing higher
compression ratios
• Does not require higher octane fuel
• Smaller fuel droplets cool the cylinder
• Mixture burns more quickly
• Less need for spark advance

38

ADVANTAGES OF GDI

• Increased fuel economy
• High power output
• Increases engine volumetric efficiency
• Lowers engine thermal loss
• Decreases emissions
• Allows higher compression
• Reduces most turbo lag when turbocharged

Direct fuel injection costs more than indirect injection systems
The injectors - exposed to more heat and pressure, more costly materials and higher-
precision electronic management systems are required.

• Rail System

Fuel supply Fuel supply (Needle Valve
Opened &
Fuel Tank Accumulator Closed)

Fuel supply

Combustion
Chamber

39

DIFFERENT

K- JETRONICS L – JETRONICS
CONTINUOUS ELECTRONIC FUEL
INJECTION SYSTEM (CIS)
INJECTION (EFI)

The fuel is injected in a Pulses of fuel are injected.
continuous stream.

The volume flow rate is The duration and frequency

regulated to engine demand of the pulses are controlled

thru largely mechanical entirely electronically

means

More fuel efficient oriented Better throttle response

40

QUESTION CHAPTER 1

1. State the function of EMS

Responsible for controlling the amount of fuel being injected and for
adjusting the ignition timing. Optimum functioning of the EMS assures
maximum engine power with the lowest amount of exhaust emission and the
lowest fuel consumption.

2. Please state the meaning of Sensor, Actuator and Electronic Control
Unit (ECU).

SENSOR:-
• A electronic device detect any variation of engine and send the data to

ECU in SIGNAL MODE.
ECU:-
• A complex electronic device receive data from SENSOR, make a

calculation and convert the data to INSTRUCTIONS MODE and send to
ACTUATOR.
ACTUATOR
• A electronic device receive an INSTRUCTIONS from ECU to do the
directed job.

41

3. Define function of sub-system of engine management system below:

a) Emission Control System
• System that responsible for the reduction of toxic gases emitted from

vehicles

b) Fuel Management System
• The fuel management system is designed to deliver precision amounts of

fuel as needed to achieve the best balance between power, fuel
economy &low exhaust emissions

c) Control/Sensor System
• System that detects a physical condition and used to collect/store

information to transfer information to ECU

4. Explain briefly the function of the sensors below:

a) Oxygen Sensor
Oxygen sensor: measure the oxygen content in the engine exhaust
system.

b) Manifold Absolute Pressure Sensor
Measure the pressure, or vacuum inside the intake manifold.

c) Throttle Position Sensor
Determine the angle of the throttle.

42