UNIT III ENGINE AUXILIARY

SYSTEMS

CONTENTS:

Electronically controlled gasoline

injection system for SI engines

Electronically controlled diesel

injection system

Unit injector system

Rotary distributor type

common rail direct injection

system

Electronic ignition system

Turbo chargers

Engine emission control by three

way catalytic converter system

Fuel supply system - Types

Gravity system -Fuel tank is mounted at the

highest position

Pressure system - Engine exhaust or air pump

Vacuum system -Engine suction

Pump system –Mechanical / Electrical fuel pump

Fuel injection system - Carburettor / Injector

Fuel supply system in petrol engine Fuel Tank

Fuel Pump

Fuel Filter

Air Cleaner

Carburettor

Inlet Manifold &

Supply And Return Pipe Lines

Fuel supply system in diesel engine Fuel Tank

Feed Pump

Fuel Filter

Air Cleaner

Fuel injection pump

Inlet Manifold &

Supply And Return Pipe Lines

Two main types of pumps most

generally used are

1. A.C. Mechanical fuel pump

2. S.U. Electrical fuel pump

AIR FUEL RATIO:

Lean mixture: 11:1

Correct mixture: 15:1

Rich mixture: 19:1

Simple Carburetor

1. Constant choke type (or) venturi type

(a) Solex carburettor

(b) Zenith carburettor

(c) Carter carburettor

(d) Stromberg carburettor

2. Constant vacuum variable choke type

(a) S.U. Carburettor

1. Float circuit

2. Starting circuit

3. Idle and slow speed circuit

4. Normal running circuit

5. Acceleration circuit

1. Float circuit

2. Starting circuit

3. Idle and slow speed circuit

4. Normal running circuit

5. Acceleration circuit

ELECTRONIC FUEL

INJECTION SYSTEM

(EFI) In modern vehicles, the engine is controlled

by

Sensors (Air/Pressure)

ECU (Computer/Monitor)

Solenoid operated fuel injectors

Right amount of fuel is injected into cylinders

1. Electronically controlled

gasoline injection system

2. Electronically controlled

diesel injection system

1) ELECTRONICALLY

CONTROLLED

GASOLINE / PETROL

INJECTION SYSTEM

I. According to the location of injector

(a) Direct injection

(b) Port injection

(c) Manifold injection

II. According to the number of injectors

(a) Single point injection

(b) Multi point fuel injection (MPFI system)

III. According to the controlling method

(a) Mechanical method

(b) Electronic method

IV. According to the duration and timing of fuel injection

(a) Continuous type(b) Intermittent type

(c) Sequential type

2) ELECTRONICALLY

CONTROLLED DIESEL

INJECTION SYSTEM

Fuel supply system in diesel engine Fuel Tank

Feed Pump

Fuel Filter

Fuel injection pump

Inlet Manifold &

Supply And Return Pipe Lines

Fuel supply system in diesel engine Fuel Tank

Feed Pump

Fuel Filter

Air Cleaner

Fuel injection pump

Inlet Manifold &

Supply And Return Pipe Lines

2) ELECTRONICALLY

CONTROLLED DIESEL

INJECTION SYSTEM

(OR)

MODERN DIESEL

INJECTION SYSTEM

TYPES OF ELECTRONIC

DIESEL INJECTION SYSTEM

Types of Electronically controlled diesel

injection system for CI engines:

1. Unit injector system (or)

Individual pump injection system

2. Rotary Distributor system

3. Common Rail Direct injection system

(CRDI)

Main parts are Pump,

High pressure fuel line, Nozzles

& Injectors

Individual pump or pump cylinder

connects directly to each fuel nozzle

Pump control the injection timing

Nozzle contains injector for all

Pump is very accurate and precise

2) ROTARY

DISTRIBUTOR TYPE

Main parts are Pump,

Distributor block, Nozzles

& Injectors

Distributor block connect with

nozzles operated by cams

Fuel is distributed to cylinders in correct

firing order

A Pump control fuel pressure & time of

injection

3) COMMON RAIL

DIRECT INJECTION

SYSTEM

Main components:

(a) Low-pressure pump

(b) High-pressure pump

(c) Common rail

(d) Electronic Control

Unit (ECU)

(e) Injectors

(f) Sensors

(g) Injection lines

(a) Low-pressure pump

It is an electrical fuel pump

It suck the fuel from the fuel tank & pumped to

high pressure pump

(b) High-pressure pump

It is a radial-piston pump

It generates high pressure

It control the engine speed

It control the fuel quantity

It suck the fuel from the Low-pressure pump &

pumped to common rail

(c) Common rail

Common rail connect with injector for

each cylinder

(d) Electronic Control Unit (ECU)

Controls the fuel pressure in the common

rail

Monitor the sensor

Control the vehicle speed

AUTOMOTIVE

ELECTRICAL SYSTEM

I. Starting system

II. Charging System

III. Ignition System

IV. Lighting System

V. Horn System

AUTOMOTIVE ELECTRICAL SYSTEM

I. Starting system

II. Charging System

III. Ignition System

IV. Lighting System

V. Horn System

AUTOMOTIVE ELECTRICAL SYSTEM -

TYPES

I. Starting system

II. Charging System

III. Ignition System

IV. Lighting System

V. Horn System and Accessories

I. Starting system

(a) Battery

(b) Starting motor

(c) Wiring

(d) Ignition switch

AUTOMOTIVE ELECTRICAL SYSTEM

II. Charging System

(a) Generator (or) DC Generator (or) Dynamo

(b) Alternator (or) AC Generator

(c) Regulator

(d) Relay

(e) Wiring

III. Ignition System

(a) Battery coil

(b) Magneto coil

(c) Electronic type

AUTOMOTIVE ELECTRICAL SYSTEM

IV. Lighting System

(a) Head lights

(b) Beam indicator lights

(c) Tail lights

(d) Parking lights

(e) Light switch

V. Horn System and Accessories

(a) Horns

(b) Horn relay

(c) Horn button

(d) Accessories

III) IGNITION SYSTEM

III) IGNITION SYSTEM

It is a spark ignition system

Engine produces a spark

This spark ignites the air fuel

mixture

TYPES OF IGNITION

SYSTEM

TYPES OF IGNITION

SYSTEM Electrical ignition system

Battery coil ignition system

Magneto coil ignition system

Rotating Armature

Rotating Magnet

Electronic ignition system

Transistorized coil ignition system

Capacitor discharge ignition system

BATTERY COIL

IGNITION SYSTEM

MAGNETO COIL

IGNITION SYSTEM -

TYPESTypes of magneto coil ignition system:

1. Rotating Armature type (R.A.)

2. Rotating Magnet type (R.M.)

1) ROTATING

ARMATURE TYPE

2) ROTATING MAGNET

TYPE

ELECTRONIC

IGNITION SYSTEM

TYPES OF

ELECTRONIC

IGNITION SYSTEM

1. Transistorized Coil Ignition System

(TCI) – Ex. Four wheeler

2. Capacitor Discharge Ignition System

(CDI) – Ex. Two wheeler

1. 1) TRANSISTORIZED COIL

IGNITION SYSTEM (TCI)

1. 1) TRANSISTORIZED COIL

IGNITION SYSTEM (TCI)

The contact points in distributor are

connected to a transistor

Transistor is connected to the ignition coil

primary windings

The transistor is made up of three slabs

Regulator

Dwell angle control system

Pulse shaping circuit

2. CAPACITOR DISCHARGE

IGNITION SYSTEM (CDI)

2. CAPACITOR DISCHARGE

IGNITION SYSTEM (CDI)

This system is widely used in two wheelers

It can be either magnetically controlled system

(or) pulse controlled system

This system differs from other systems as the

electric energy stored in the capacitor

A capacitor is used to store the energy

TURBO

CHARGER

TURBOCHARGER – CROSS-SECTION

TURBOCHARGER -

COMPONENTS

Components of turbocharger:

Turbine

Air compressor

Inter-cooler

TURBOCHARGER

A turbocharger is a small radial fan pump

A turbocharger consists

Turbine &

Air compressor on a shaft

Inter-cooler

The turbine converts exhaust to rotational force,

which is in turn used to drive the compressor

The compressor draws in ambient air and pumps it

in to the intake manifold at increased pressure

Resulting in a greater mass of air entering the

cylinders on each intake stroke.

TURBOCHARGER -

ADVANTAGES

1. Good torque

2. Good accelerating

3. High power

TURBOCHARGER -

DISADVANTAGES

1. System is complex

2. High fuel consumption

THREE WAY CATALYTIC

CONVERTER

CATALYTIC CONVERTER -

INTRODUCTION

A catalytic converter is a device

used to reduce the toxicity(dead line)

of emissions from an I.C. engine

The catalytic converter was

invented by Eugene Houdry, a

French mechanical engineer

CATALYTIC CONVERTER -

TYPES

Types of catalytic converter:

1) Two way converter

2) Three way converter

1) TWO WAY CONVERTER

It is widely used on diesel &

gasoline engines

To reduce

Carbon monoxide and

Hydrocarbon emissions

Inability to control NOx led, so

we use three-way converters.

1) TWO WAY CONVERTER

- TWO FUNCTIONS

A two-way catalytic converter has two

simultaneous tasks:

1) Oxidation of carbon monoxide to

carbon dioxide

2) Oxidation of un-burnt hydrocarbons

to carbon dioxide and water

2) THREE WAY CONVERTER

2) THREE WAY CONVERTER -THREE FUNCTIONS

A three-way catalytic converter has three

simultaneous tasks:

1) Oxidation of carbon monoxide to

carbon dioxide

2) Oxidation of un-burnt hydrocarbons

to carbon dioxide and water

3) Reduction of nitrogen oxides to

nitrogen and oxygen

1) A.C. Mechanical & S.U. Electrical fuel pump

2) Carburetor working & types (Simple & Solex carburettor)

3) Electronic gasoline injection system & types

SPFI system

MPFI system & types

4) Electronic diesel injection system & types

Unit injector system

Rotary distributor type

Common rail direct injection (CRDI) system

5) Ignition system

Battery coil ignition system

Magneto ignition system & types (RA & RM)

6) Electronic ignition system

Transistorized coil ignition system(TCI)

Capacitor discharge ignition system (CDI)

7) Turbo chargers - operation, sketch

8) Engine emission control by three way catalytic converter