eBook Automotive Technology

5. With aid a diagram, please describe the operation of EFI system

Fuel is delivered from the tank to the injector by means of an electric
fuel pump. The pump is typically located in or near the fuel tank.
Contaminants are filtered out by a high capacity in line fuel filter.
Fuel is maintained at a constant pressure by means of a fuel pressure
regulator. Any fuel which is not delivered to the intake manifold by the
injector is returned to the tank through a fuel return pipe.

43

6. Fuel pressure regulator is one component in the EFI system. With
the aid of diagrams explain the operations of fuel pressure regulator.

i. Located at end of fuel rail
ii. Maintains constant pressure at injectors
iii. Internal chamber contains a diaphragm

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

7. Describe advantages of Electronic Fuel Injection System

i. Uniform air-fuel ratio mixture distribution

ii. Highly accurate air-fuel ratio control throughout an engine

operation condition

iii. Excellent fuel economy with improved emissions control

iv. Improved cold engine start ability and operation 44
v. Superior throttle response and power

8. Explain with diagram the differences between THREE (3)
types of fuel Injection system.

Single Point Injection Multipoint Injection Direct Injection
i. Single Point - Use only one injector located before TPS, use in earlier

version of EFI engine & intake manifold will full with mixture of air and
fuel from the throttle body until intake valve
ii. Multipoint – Use 4 injectors for each cylinder in manifold, replace the
single point injection used in previous model of EFI engines & intake
manifold only will consist of air. Fuel will only sprayed at the of the
runner in the intake manifold or before intake valve
iii. Direct – Injector sprays directly into cylinder, latest type of fuel
injection system available & intake manifold only consists of air. Fuel
will be sprayed in the combustion chamber.

45

CCHHAAPPTTEERR21

ENGINE 4466
FORCED
MANAGEMENT
INDUCTIONS
SYSTEM
SYSTEM

(EMS)

• A process of compressing air on the
intake of an internal combustion
engine by a gas compressor.

• A forced induction engine aims to
increase the pressure, temperature
and density of the air.

• An engine without forced induction
is considered a naturally aspirated
engine

• -Forced induction is used in the
automotive industry to increase engine
power and efficiency

• - It is not commonly used, however,
because a forced induction system is
expensive and complicated, and the
engine must be specifically designed to
handle it effectively.

47

Proton Campro 1.6L CFE
Ford 1.0L Ecoboost

48

FORCED Turbocharges
INDUCTIONS Supercharges

SYSTEM

TURBOCHARGES

A turbocharger is a centrifugal
compressor driven by the flow of
exhaust gasses

SUPERCHARGES

• An air compressor used for forced induction of
an internal combustion

• Power for the unit can come mechanically by a belt,
gear, shaft, or chain connected to the
engine's crankshaft
49

TURBOCHARGES

CONSTRUCTION

INSIDE TURBOCHARGER

50

…TURBOCHARGER

TURBOCHARGER OPERATION

Exhaust gases will flow out directly to TURBINE

1 WHEEL, at the same time its made turbine wheel

were spin in high revolution 240,000 rev/min.

2 The COMPRESSOR WHEEL is connected to

TURBINE WHEEL with a SHAFT. In high
revolution, compressor wheel will draw air from
outside to compress.

3 This condition causes the air to be heated. This hot

air will be directed to the intercooler for cooling.

4 High-pressure cold air to be channeled into the

combustion chamber.

5 After the combustion process, exhaust gases will

be used to move the turbine wheel before it

is discharged through the exhaust muffler. 51

…TURBOCHARGER

• A turbocharger relies on the volume and velocity of exhaust gases to spin (spool) the
turbine wheel, which is connected to the compressor wheel via a common shaft.

1 A smaller turbo 2 Deliver full boost 3 But boost
will spool quickly pressure at low pressure will
engine speeds suffer at high
engine RPM.

1 A larger turbo, 2 Thus, it will has a 3 But it provides
on the other turbo lag improved high-
rev performance
hand, will takes at the expense
of low-end
longer to spool response..

COMPONENTS Waste Gate
IN Blow Off
Valve
TURBOCHARGED
SYSTEM Intercooler

What is turbo lag ?? 52
Page 57

WASTE GATE

• A valve that allows the exhaust to bypass the turbine blades.

The waste If the pressure so the waste allowing the
gate senses gets too high, gate blades to slow
it could be an
the boost indicator that bypasses down.
pressure. the turbine is some of the
spinning too
exhaust
quickly, around the

turbine
blades,

Operation Of Wastegate

53

…WASTE GATE
Internal
External

Mounting Position

54

BLOW OFF VALVE

• Blow off valves function to stop compressor
surge.

• Compressor surge happens with the lifting
the throttle off a turbocharged vehicle that
either doesn't have a bypass valve.

A

B

55

INTERCOOLER

• An intercooler’s purpose is to cool air that has
compressed in either a turbo or supercharger.

• When air is compressed its temperature rises
drastically and becomes less dense and less
oxygen rich.

• An intercooler is an essence a heat exchanger

56

How forced air induction works?

TURBO LAG

• Turbo lag is defined as the time gap (delay) between the
throttle being pressed and the turbocharger responding,
resulting in a delayed delivery of power.

• The turbo lag is the time it takes to create enough exhaust
pressure to spin the turbo and pump compressed intake air
into the engine

• It is longest when the engine is in a low-rpm, low-load
cruising situation.

How to reduce turbo lag? 1 Twin scroll turbo
2 Variable geometry turbo
3 Nitrous
4 Sequential turbo
5 Electric hybrid turbo 57

SUPERCHARGES

POSITIVE DISPLACEMENT

Positive-displacement pumps deliver a nearly fixed volume of air per
revolution at all speeds

TYPES IN Roots
SUPERCHARGER Lysholm
Screw

Centrifugal

58

ROOTS TYPE

The Root type supercharger or Roots
blower is a positive displacement lobe
pump which operates by pumping fluids
with a pair of meshing lobes not unlike a
set of stretched gears. Fluid is trapped in
pockets surrounding the lobes and
carried from the intake side to the
exhaust.

SCREW TYPE

• Lysholm is also called screw type supercharger.
• The supercharger consists of 2 screws, one with

male threads. They closely mesh together. When
they rotate, air is captured between the screws
and the housing while being pushed from the inlets
towards the outlet. Moreover, the space gets
smaller and smaller as it moves forward, so Lysholm
performs internal compression and enables higher
boost pressure than Roots type supercharger.

CENTRIFUGAL TYPE

The centrifugal type supercharger is an engine-driven

compressor used to increase the power output of an

internal-combustion engine by increasing the amount of

available oxygen by compressing air that is entering the

engine. This type of supercharger is practically identical in

operation to a turbocharger with the exception that

instead of exhaust gases driving the compressor via a

turbine, the compressor is driven from the crankshaft by a

belt, gear or chain drive. 59

PROBLEMS WITH FORCED INDUCTION SYSTEM

1 The engine temperature is rising very quickly.

High combustion temperatures lead to higher NOx

2 emissions and high compression causes high

combustion temperatures.

Another problem with high combustion

3 temperatures is that the fuel can ignite before

the spark ignites it or burn too quickly after the

spark ignites it. (called pre-ignition cause of

knocking) 60

ADVANTAGES & DISADVANTAGES

FORCED ADVANTAGES DISADVANTAGES
INDUCTIONS
✓ Produce more horse ✓ Have many parts
SYSTEM power, (components)

TURBOCHARGER ✓ Having light parts, ✓ Having “Turbo Lag”
✓ More cheaper than (lagging time), need
time to turbo spool up.
superchargers parts
✓ Produce unlimited boost. ✓ Need additional parts
to cooling the air
entering combustion
chamber (intercooler)

SUPERCHARGER ✓ no lag time to build ✓ Need more space to
pressure because the installation of
compressor is always superchargers.
spinning proportionally
to the engine speed. ✓ More expensive than
Turbochargers.
✓ able to produce the
same boost pressure at
every engine speed.

✓ Less parts
(components)

61

QUESTION CHAPTER 2

1. What is Forced Induction System?

Force Induction is forcing additional air-fuel mixture into the cylinder.
Forced induction is the process of delivering compressed air to the
intake of an internal combustion engine

2. Explain with the diagram of the air induction system in a vehicle
and explain its operation.

i. When the throttle valve is opened, air flows through the air
cleaner to be filtered.

ii. Then air will through the air flow meter (on L type systems), past
the throttle valve in throttle body.

iii. ECU will determine the air fuel ratio based on input from throttle
position sensor. Then, air will be channeled through a well-tuned
intake manifold runner to the intake valve before entering the
cylinder.
62

3. Write the meaning of a 'turbo lag' in the Forced Induction System
and give the solution to reduce a turbo lag in the system.

'Turbo lag' is a time required to boost the pressure and rotate the
turbine. The solution to reduce turbo lag is using supercharger and use
small turbocharger.

a. Give the types of Supercharger System
b. Root Supercharger
c. Twin-Screw Supercharger
d. Centrifugal Supercharger

4. Sketch and explain the operation of Turbocharger System.

a. Using the energy from the engine exhaust gasses, turbine wheel &
wheel compressor are turned which attached on the same axis. This
compresses air and forces it into the engine

b. The amount of air (pressure) forced into the engine is referred to
as boost pressure and can be adjusted by controlling the amount
of exhaust (blow off)

c. Gas which passes through the turbo and adjustment is performed
by the bypass valve (waste gate) which is between the engine
and turbo and release the exhaust gas without flowing through
the turbo

d. This is activated by the compressor pressure by raising boost
pressure the engine is able to take in more air
63

5. Elaborate the working operation of a supercharger system.

i. Superchargers increase intake by compressing air above atmospheric
pressure, without creating a vacuum. This forces more air into the engine,
providing a "boost." With the additional air in the boost, more fuel can be
added to the charge, and the power of the engine is increased.

ii. Superchargers draw their power directly from the crankshaft. Most are
driven by an accessory belt, which wraps around a pulley that is
connected to a drive gear. The drive gear, in turn, rotates the compressor
gear.

iii. For a supercharger to work at peak efficiency, the compressed air exiting
the discharge unit must be cooled before it enters the intake manifold. The
intercooler is responsible for this cooling process.

6. Explain the advantages of the EFI system compared carburator system.

i. Uniform Air/Fuel Mixture Distribution

Each cylinder has its own injector which delivers fuel directly to the intake valve.
This eliminates the need for fuel to travel through the intake manifold.

ii. Highly Accurate Air/Fuel Ratio Control

Throughout All Engine Operating Conditions EFI supplies a continuously accurate

air/fuel ratio to the engine no matter what operating conditions. This 64
provides better performance, fuel economy, and emissions control.

iii. Excellent Fuel Economy With Improved Emissions Control
Cold engine and wide open throttle enrichment can be reduced with an EFI
engine because fuel paddling in the intake manifold is not a problem. These
results in better overall fuel economy and improved emissions control.

iv. Improved Cold Engine Start ability and Operation
The combination of better fuel atomization and injection directly at the
intake valve improves ability to start and run a cold engine.

v. Superior Throttle Response and Power
By delivering fuel directly at the back of the intake valve, the intake manifold
design can be optimized to improve air velocity at the intake valve. This
improves torque and throttle response.

7. Sketch and explain working operation of a wastegate in
turbocharger system.

• A valve that allows the exhaust to bypass the turbine blades.
• They limit the exhaust gases that flow through the turbocharger.

Therefore, control the maximum boost pressure produced by the
turbocharger itself.

65

CCHHAAPPTTEERR31

EMENISGSIIONEN
MCAONNATGREOMLENT

SSYYSSTTEEMM

(EMS) 6666

OBJECTIVES

Classify types of vehicle emission sources

Identify exhaust emission pollutants and
their effects to human health

1 a. hydrocarbon, HC

b. carbon monoxide, CO
c. oxide of nitrogen, NOx
d. particulate matter, PM
e. Sulfur Oxide, Sox

2 Identify fuel evaporation sources

3 Describe “blow-by gas”

Emission control systems

Identify types of emission control systems

1 a. Catalytic Converter

b. Exhaust Gas Recirculation Systems, EGR
c. Positive Crankcase Ventilation System, PCV
d. Evaporative Emission Control System, EVAP
e. Secondary Air Injection System

2 Describe overall layout of emission control systems

3 Identify components name, function and location of

emission control system

67

3.1 TYPES OF VEHICLE EMISSION SOURCES

3.1.1 EXHAUST EMISSION POLLUTANTS AND THEIR EFFECTS
TO HUMAN HEALTH

68

TYPES OF VEHICLE EMISSION SOURCES

1 HYDROCARBON • In the form of unburned gasoline
• Incomplete burning of any
(HC)
organic matter or combustion

engine exhaust

Effects

• Reduce the amount of available oxygen
• Considered hazardous air pollutants or air toxins and can lead to the

development of cancer

• Created when the heat in the engine

2 OXIDE OF forces nitrogen in the air to combine
with oxygen within the combustion

NITROGEN chamber
• Nitrogen dioxide (NO2) is a gas of

(Nox) reddish-brown color with a distinct
sharp, biting odor

Effects

• General irritation to the eyes
• Irritation of the respiratory system
• Shortness of breath

Particles matter are either classified as :-

3 PARTICULAR • Primary particulates
✓ directly emitted into the

MATTER atmosphere i.e. road traffic
• Secondary particulates

(PM) ✓ generated in the atmosphere e.g.
the oxidation of sulphour dioxide

into sulphuric acid.

Effects

• Cardiovascular 69
• Respiratory problems

…TYPES OF VEHICLE EMISSION SOURCES

4 • Carbon monoxide is a colorless,

CARBON odorless gas which is highly toxic to

MONOXIDE humans
(CO) • The combustion of carbon-based fuels

produces carbon dioxide (CO2)

Effects

• Toxicity of the central nervous
system and heart

• Severe effects on the baby of
a pregnant woman

• Headaches and dizziness

• Problems with getting oxygen
supplied to some body parts
which may be life-threatening

How CO become higher :-

• Dirty air filter - A dirty air filter prevents air flow, thus

• disturbing the ratio of air / fuel(14.7:1) needed for optimum

• combustion of fuel

• Defective Oxygen sensor (O2 sensor)

• Defective MAP sensor - Defective MAP sensor will not report

• correct information to the ECU, thus disturbing the ratio of air / fuel

• Defective Throttle position sensor (TPS) - confuse the ECU to
determine whether the fuel is more or less, when really not necessary

• Defective Engine Coolant Temperature (ECT) Sensor -

low engine temperatures require more fuel. When the ECU is unable to determine

the exact temperature of the engine, it can not determine the rate of the

fuel properly and caused high CO 70

HEALTH EFFECTS OF POLLUTION

What happens during combustion:
HC + N + O₂ = CO₂ + H₂O + CO + NOx + HC

* Notice that HC appears on the right side of equation. This shows that some of the
gasoline does not burn and come out in the exhaust gas

Complete . CO2
Combustion
of HC + O H2O

.

Incomplete . CO2 NOx
Combustion
of HC + O . H2O CO

HC 71

…TYPES OF VEHICLE EMISSION SOURCES

SULFUR • Formed when fuel containing sulfur
5
OXIDE (coal & oil) is burned

• Oxides combine with other substances

(Sox) in the air to produce a haze that

reduces visibility

Effects
• Reduced lung function
• Increased incidence of respiratory symptoms and diseases
• Irritation of the eyes, nose & throat

3.1.2 FUEL EVAPORATION SOURCES

There are 4 major ways in which these gasoline vapours;

1. Daily evaporation (Sejatan Harian)

• Occurs during the daylight hours when the fuel is heated by an increase in ambient
temperature. The rise in temperature increases vaporization.

2. Running losses (Kehilangan semasa berjalan)

• Heat in the engine compartment from the exhaust system and the operation of the
engine, both of which cause fuel vaporization

3. Hot soak (Serapan)

• After an engine is turned off, the radiant heat will cause gasoline vaporization for an
extended period as long as one hour

4. The time of refueling (Masa isi minyak)

• Fuel vapors are always present in the fuel tank. When liquid fuel is added to the tank,
it displaces the vapors by venting them into the atmosphere
72

3.1.3 BLOW-BY GAS

Blow-By: on other side also

• Leakage of the air-fuel mixture or of combustion gases between a piston and the
cylinder wall into the crankcase of an automobile

• While the engine is running, some gases from combustion leak between the piston rings
and the cylinder walls, down into the crankcase

• Unburned fuel & water from condensation also find their way into the crankcase & sump
73

Catalytic Converter

TYPES Exhaust Gas Recirculation
OF Systems, EGR

EMISSION Positive Crankcase
CONTROL Ventilation System, PCV
Secondary Air Injection

System

Evaporative Emission Control
System, EVAP

CATALYTIC CONVERTER

A EXHAUST MANIFOLD A D
C
Designed to take gases from the B
engine cylinders and channel 74
them into the exhaust. D MUFFLER

B CATALYTIC Designed to further reduce
noise and channel exhaust
CONVERTER gases away from the vehicle.

Designed to reduce the number
of harmful pollutant gases.

C CENTER SECTION

Some vehicles feature a center
section designed to reduce
noise.

…CATALYTIC CONVERTER
Exhaust And Emission System

How A Catalytic Converter Works

75

…CATALYTIC CONVERTER

Catalyst helps to convert carbon monoxide into carbon dioxide
It converts the hydrocarbons into carbon dioxide and water / nitrogen and oxygen
TWO different types of catalyst

1. reduction catalyst (pengurangan)
- platinum + rhodium

2. oxidation catalyst (pengoksidaan)
- platinum + palladium

Effect

Carbon monoxide is a poison for any air-breathing
Nitrogen oxides lead to smog and acid rain & hydrocarbons produce smog

76

EXHAUST GAS RECIRCULATION (EGR)

• Controls an engine’s emission of smog-
causing nitrous oxides (NOx)

• To route a portion of the exhaust
gases back into the intake manifold

• This dilutes the O2 in the incoming air
stream and provides gases inert to
combustion to act as absorbents of
combustion heat to reduce peak in-
cylinder temperatures.

• Because NOx forms primarily when a

mixture of nitrogen and oxygen is

subjected to high temperature, the

lower combustion chamber

temperatures caused by EGR reduces

the amount of Nox.

The variables measured can include:

EGR pressure
Exhaust gas temperature
EGR Position

77

…EXHAUST GAS RECIRCULATION (EGR)

• EGR valve controls a small passageway between the intake and exhaust manifolds
• Oxide of Nitrogen (Nox) is produced as a by-product of combustion

EGR flow is controlled by the engine’s computer, which opens or closes the 78
valve as needed
The ECU now has control over this valve and monitors several inputs to
determine the amount and timing of operation

POSITIVE CRANKCASE VENTILATION (PCV)

PCV System

• To reduce the pressure in crankcase due to

blow-by gases.

• High pressure in crankcase potential

damage:

i. Oil contamination

ii. Blow crankcase seal

iii. Leakage at the gasket

iv. Engine oil sludge

• Control device which sends partially burned

gases that come from the engine's crankcase

to the combustion chamber

• Keeps the system free of moisture due to the

constant air circulation

• PCV valve routes crankcase 79
partially burned gases back to

the engine.

PCV System Components :
• i. PCV Valve
• ii. PCV purge hose
• iii. Breather hose

• This system also uses manifold
vacuum to draw crankcase vapors
back into the intake manifold

• - Typically, blow-by production is
the greatest during high load
operations and very light during
idle and light load operations

80

EVAPORATION CONTROL SYSTEM (EVAP)

Early Version of EVAP

81

EVAPORATION EMISSION CONTROL SYSTEM (EVAP)

EVAP System

• The gasoline in fuel tank slowly evaporates over time, releasing volatile organic
compounds into the air

• EVAP - collects, removes and disposes of the vapors before they can escape into the
atmosphere or enter into vehicle compartment

• The EVAP system usually requires no maintenance, but faults can turn on the Check
Engine light and prevent a vehicle from passing an OBD II plug-in emissions test.
82

PRESSURE FUEL FUEL
SENSOR CAP TANK

• Monitor EVAP system • Seals fuel system ▪Stores the liquid fuel
vacuum • Allows for refueling

EVAP Components

PURGE VENT CHARCOAL
VALVE VALVE CANISTER

• Commanded open by the • Allows air in fuel tank • Absorbent charcoal
PCM to allow the engine to be displaced when inside the canister
to draw the fuel vapors adding fuel to tank. captures fuel vapors
out of the charcoal as they evaporate
canister. • Normally open valve from the tank.
- Closes when power
• Only does this when the is applied
engine is at operating
temperature. 83

• Without the purge valve,
the charcoal will become
saturated with fuel.

• Used in conjunction with a
pressure sensor to test
system for potential leaks

• Normally closed valve
• Opens when power
is applied

Modes of EVAP System

• Vehicle shut off • Purge valve open
• Allows for air to escape fuel tank due • Vent mode closed
• Draws fuel vapors out of charcoal
to thermal expansion of fuel as well
as refueling canister to be burned in the engine

• System open to atmospheric pressure
• No power supplied to components
• Vent valve open
• Purge valve closed

84

SECONDARY AIR INJECTION

Secondary Air Injection System 85

• Secondary air injection systems
pump outside air into the
exhaust stream so unburned fuel
can be burned.

• Early air systems have a belt-
driven air pump. Newer aspirated
air systems use the vacuum
created by an exhaust pulse to
pull air into the pipe. The latest
systems use an electric motor to
pump air.

QUESTION CHAPTER 3

1. Identify the types of Emission Control Systems in vehicles and
explain the function for each system.

• Catalytic Converter –
To reduce hydrocarbon and toxic gases in an exhaust pipe.

• Exhaust Gas Recirculation System (EGR) –
Allows burned gases to enter the engine intake manifold to help
reduce NOx.

• Positive Crankcase Ventilation System (PCV) –
uses engine vacuum to draw blow-by gases into the intake manifold
for rebuming in the combustion charnber.

• Air Injection System –
Forces fresh air into the exhaust ports or catalytic converter to reduce
HC/CO.

• Evaporative Emission Contol System (EVAP) –
• Prevents toxic fuel system vapours from entering the atrnosphere.

2. Describe function of Catalytic Converter in vehicle.

• Catalyst helps to convert carbon monoxide into carbon dioxide.
• It converts the hydrocarbons into carbon dioxide and water /

nitrogen and oxygen

86

3. List of poisonous gases in exhaust system.

a. Carbon Monoxide (CO)
b. Hydrocarbon (HC)
c. Particular Metter (PM)
d. Sulphur Oxide (Sox)
e. Nitrogen Oxide (NOx)

4. Identify the effects of exhaust emission pollutants to human health

a. Toxicity of the central nervous system and heart
b. Severe effects on the baby of a pregnant woman
c. Headaches and dizziness
d. Problems with getting oxygen supplied to some body parts which

may be life-threatening
e. General irritation to the eyes
f. Irritation of the respiratory system
g. Shortness of breath

87

REFERENCES

1. Erjavec J. and Thompson R. (2019), Automotive
Technology: A System Approach, 7th Edition, Cengage

Delmar Learning.

2. Duffy J. E. (2017), Modern Automotive Technology, 9th
Edition, The Goodheart- Willcox Publisher.

3. Halderman J. D. (2019), Automotive Technology: Principles,

Diagnosis, and Service, 6th Edition, Pearson

Education.

viii