Fuel Injection System

By V.SHYAMU

Fuel Injectors

Introduction

Fuel injection is a system for admitting

fuel into an Internal Combustion Engine

Fuel injection atomizes the fuel by forcibly pumping it through a small nozzle under high pressure

Objectives

Power output

Fuel efficiency

Emissions performance

Accommodate alternative fuels

Reliability

Driveability and smooth operation

Initial cost

Maintenance cost

Diagnostic capability

Range of environmental operation

Engine tuning

Strict emission standards require precise fuel delivery.

Computers used to calculate fuel needs.

EFIS is very precise, reliable & cost effective.

EFI provide correct A/F ratio for all loads, speeds, & temperature ranges.

Injector

Electromechanical device

Controlled by ECM

Engine rpm determines

when injector opens

How long it stays open determined

by:

Engine temp

Engine load

Throttle pos.

O2 sensor voltage

FunctioningM

eter

ing

Injector

uses

solenoid

Mass

airflow

sensor

Throttle position sensor Fuel Pump

Fine tuning

by Oxygen

Sensor

Injectors in operation

Various Injection Schemes

Single Point Injection (SPI)

Continuous InjectionCentral Port Injection (CPI)

Multi Point Injection (MPI)

Direct InjectionSwirl Injection

Diesel Engines

Petrol Engines

Injection

Single Point

Injection

Injects Fuel at throttle

body

Fuel Pressure- 10-15 psi

Continuous Injection

Flows at all times

Fuel Distributor

Central Port Injection

Poppet valves

Batch fire

Multi Point Injection

Injects into intake ports

40-60 psi

Sequential Batched

Injection

Direct

Injection

Higher precision 26000 psi

Swirl Injection

angular

Gas turbine liquid rocket

Injection

Advantages

EFI systems require little regular maintenance whereas carburettors typically requires seasonal and/or altitude adjustments.

Airflow is often improved with fuel injection, the components of which allow more design freedom to improve the air's path into the engine.

By optimizing the homogeneity of cylinder-to-cylinder mixture distribution, all the cylinders approach their maximum power potential and the engine's overall power output improves.

Dis-Advantages

An EFI system requires several peripheral components in addition to the injector(s), in order to duplicate all the functions of a carburettor.

During times of fuel metering repair is that early EFI systems are prone to diagnostic ambiguity.

A single carburettor replacement can accomplish what might require numerous repair attempts to identify which one of the several EFI system components is malfunctioning.

Carburetor

13

Fuel system components• FUEL INJECTION PUMP - Fuel injection pump sucks fuel from the tank ,

pressurizes the fuel to approx. 600 - 1000 bar and sends it to the injectors.– Inline FIP - Has separate pumping chambers for each cylinder– Rotary FIP(Distributor pump) - Has one pumping chamber and the pump distributes

to each cylinder as per sequence- firing order

• INJECTORS - Inject the high pressure fuel in to each cylinder.

• FUEL FILTER - Filters the fuel from dirt & sediments, since the Fuel injection pump requires clean fuel.

Fuel system components• FUEL INJECTION PUMP - Fuel injection pump sucks fuel from the tank ,

pressurizes the fuel to approx. 600 - 1000 bar and sends it to the injectors.– Inline FIP - Has separate pumping chambers for each cylinder– Rotary FIP(Distributor pump) - Has one pumping chamber and the pump distributes

to each cylinder as per sequence- firing order

• INJECTORS - Inject the high pressure fuel in to each cylinder.

• FUEL FILTER - Filters the fuel from dirt & sediments, since the Fuel injection pump requires clean fuel.

15

Mechanical Fuel Pump

Fuel pump mechanical

17

Fuel pump electrical

18

Injection system

In the C.I. engine the fuel is injected intothe combustion chamber, it the has to mixthoroughly with the air, ignite and burn all at the same time. To insure this happens, twotypes of combustion chamber have beendeveloped.

DirectInjection

Indirect Injection

Fuel Injector

20

Common rail fuel injection system

21

22

Common rail injection system

Air Intake and exhaust system

23

24

Supercharger

• It takes power from engine to compress the air by using belt drive.

25

muffler/ silencer

26

Mufflers

27

29