14-05-2013, 01:07 PM
Fuel Injection Systems
Fuel Injection.ppt (Size: 805 KB / Downloads: 175)
Aim
To be able to describe the operation of an injection system within an internal combustion engine
Objectives
Be able to describe the operation of an injection system within an internal combustion engine
Be able to recognize a single point injection system and a multi-point injection system
Identify how fuel and air is atomized within a fuel injection system
The role of the Injectors
The injector delivers a finely atomized spray of fuel into the inlet port
The injectors also vary the amount of fuel delivered to suit the engines conditions
The spray is obtained by passing fuel (that is pressurised) through the nozzle of the injector
It is located in the inlet manifold near the cylinder head intake port
Injectors
The opening of the injector is controlled by the vehicles ECU
The injector is supplied with the battery voltage via a relay, the earth circuit is controlled by the ECU
When the circuit is completed by the ECU a solenoid operates, the injector valve opens, fuel is then able to be sprayed into the inlet manifold
The valve moves roughly 1.5-10 milliseconds. This is known an injector duration or opening time
The ECU will make amendments to the duration depending on engine temperature, loading air temperature and battery voltage
Fuel Atomisation
During fuelling of a cylinder the fuel is pressurised which causes the fuel to become a vapour, allowing it to burn easily (compared to the fuel being delivered to the cylinder in liquid form)
Multi point injection system
The multi point injection system is the most common type of fuelling system that is used on modern vehicles today
This is mainly due to the fact that this injection system can be controlled easily by the vehicles ECU
Furthermore, this type of fuelling system provides a better method of burning the fuel without much wastage. Compared with other fuelling systems
Summary – have we ?
Been able to describe the operation of an injection system within an internal combustion engine
Been able to recognize a single point injection system and a multi-point injection system
Identified how fuel and air is atomized within a fuel injection system