Prepared By:Upadhyay Ayush. (150123119053)

GANDHINAGAR INSTITUTE

OF

TECHNOLOGY

ACTIVE LEARNING ASSIGNMENT

ON

“Type of Injection System”

INTERNAL COMBUTION ENGINE[2161902]

MECHANICAL 6 (D3)

GUIDED BY:-

Prof. HARDIK GOHEL

Introduction

Fuel-Injection System is vital to the working and

performance of CI engine. This system serves the purpose

of initiating and controlling the combustion to meet the

demand requirements.

Fuel is injected into combustion chamber towards the end

of compression. It is atomized as it enters under high

velocity and the droplets get vaporized to form a fuel-air

mixture. Due to continued heat transfer from hot air to fuel,

the fuel reaches to its self ignition temperature to ignite

spontaneously initiating combustion. Depending upon the

demand requirements the fuel injection system continues

to deliver the fuel during initial part of combustion.

3/23/2017 I.C.E 2

Classification

3/23/2017 I.C.E 3

Injection System

Air Injection

Solid Or Airless

Injection

Common rail system

Individualpump and

injector system

Distributorsystem

Air Injection System

In this system fuel is injected along wit high pressure air into

combustion chamber. The pressure of this air is about 70 bar. A

multistage air compressor is required to supply the blast of air at

high pressures. A fuel pump draws fuel from fuel tank through a

filter and discharge a definite quantity into an injector. The high

pressure air from compressor is also led to the injector valve which

force the fuel, through the nozzle, when it is opened mechanically.

This type of system is not used now-a-days in diesel engines.

3/23/2017 I.C.E 4

3/23/2017 I.C.E 5

Advantages:- It provides good atomization and distribution of fuel.

Fuel pump needs to develop less pressure.

It requires high pressure multi stage compressor.

Air compressor needs extra maintenance.

Disadvantages:-

Solid Injection Or

Airless injection system

In solid Injection system , fuel is directly injected into thecylinder without aid of compressed air. That’s why this systemis called solid or airless injection system.

Fuel is supplied at very high pressure (about 200 bar) fromfuel pump to fuel injector from where it is injected to thecombustion chamber with the help of injector.

There are three types as:

1. Common rail system

2. Individual pump and injector

3. Distributor injection system

3/23/2017 I.C.E 6

Common Rail Injection System

In this system, single fuel pump supplies high pressurediesel oil to common rail or header.

High pressure in the header forces fuel to each of thenozzle. At given instant, the fuel is injected in a specificcylinder by a mechanically operated valve, by means of apush rod and rocker arm.

The amount of fuel is regulated by varying the length ofthe push rod stroke. The pressure in header is as perinjector design for penetration & dispersion of fuel incombustion chamber.

3/23/2017 I.C.E 7

It can control fuel supply according to load and speed of the

engine.

Only one pump is required for multi cylinder engine.

The arrangement of system is very simple & Maintenance

cost is less.

3/23/2017 I.C.E 8

Advantages:-

Disadvantages:-

Very accurate design and workmanship is required.

Individual Pump & Injector

3/23/2017 I.C.E 9

In this system , individual fuel pump is provided for each

nozzle. The metering of fuel quantity and control of injection

timing are done by the each pump for corresponding nozzle.

The needle valve in nozzle is actuated by fuel oil pressure.

The amount of fuel entering the cylinders is regulated by

changing position of control rack.

Distributor Injection System

In this system, the pump is used to pressurizes, meters and times

the injection. Then fuel is supplied to central distributor block.

From distributor block fuel is distributed to each cylinder in correct

firing order by cam operated poppet valves which open to admit

fuel to nozzles.

The amount of fuel to entering the cylinders is regulated by

changing position of control rack. The number of injection strokes

per cycle for the pump is equal to the number of cylinders.

3/23/2017 I.C.E 10