Fuel injection is a system for
mixing fuel with air in an internal combustion engine.
Functional objectives for fuel
injection systems vary but all of them share the central task of supplying fuel
to the combustion process. There are several competing objectives such as:
Power output, fuel emission,
emissions performance, reliability, smooth operation, initial cost, maintenance
cost.
Requirements
of fuel injection system are:
- Accurate metering of the fuel injected per cycle: The quantity of the fuel metered should vary to met changing speed and load requirements of the engine
- Timing the injection of the fuel correctly in the cycle: to obtain maximum power ensuring fuel economy and clean burning.
- Proper control of rate of injection: The desired heat - release pattern is achieved during combustion.
- Proper atomization of fuel into very fine droplets.
- Proper spray pattern to ensure rapid mixing of fuel and air.
- Uniform distribution of fuel droplets throughout the combustion chamber.
- To supply equal quantities of metered fuel to all cylinders case of multi cylinder engines
- No lag during beginning and end of injection i.e., to eliminate dribbling of fuel droplets into the cylinder.
Automobile
Engineering, Fuel injection system