Petrol Injection System Essay

Name: Nagesh Kom

Assignment no: 1

Unit no: 8

Unit name: Function and Operation of Vehicle Petrol Injection System

Task: 1

Explain the operation of multi-point and single point petrol injection systems used on modern fuel injected engines.

 Multi point injection system:

The multi-point injection system is also called port injection system. It has each cylinder give separate injector, to spray air fuel mixture in the port going to each cylinder. In the multi-point injection system has an inlet connection from the fuel rail and an outlet that lets fuel return to the fuel tank.

Class notes

Operation of Multi point injection system:

In Multi point injection system there is a separate injector for each cylinder

Stoichiometric ratio is also called lambda ratio. For the gasoline fuel, or petrol the value of the ratio is 14.7 parts of air and 1 part of fuel. So if lambda equals 1, the air-fuel mixture is at the Stoichiometric ratio, of 14.7 to 1 (14.7:1). If an air-fuel mixture has a higher figure, say, 1.03, there is more air in proportion to the fuel than 14.7 to 1, and the mixture is slightly lean. A mixture with a lower lambda value, say 0.97, has proportionately less air than fuel, and the mixture is slightly rich. The exhaust gas oxygen sensor is also called the lambda sensor, since it can be used to maintain the air-fuel ratio at lambda equal to 1, within very close limits. It can be installed in the exhaust manifold, where it measures the percentage of oxygen in the exhaust gases. A high percentage of oxygen may mean too little fuel is entering the engine, the mixture is too lean, and lambda is greater than 1. The sensor delivers this information to the ECU, which adjusts the mixture accordingly. Similarly, a low percentage of oxygen less than 1.Different fuels have a different Stoichiometric ratio. For instance, with Methanol the air-to-fuel ration is 6.4:1, and with Ethanol it is