INVESTIGATION OF THE EFFECT OF INJECTION PRESSURE ON ENGINE SPECIFIC FUEL CONSUMPTION AND EXHAUST EMISSIONS IN TURBOCHARGED DIESEL ENGINES

Fuel injection pressure on diesel engines play an important role in engine performance and emissions obtaining treatment of combustion. In the present diesel engines such as common rail diesel engine, the injection pressures can be increased about 1500-2000 bars. In this study , the effects of injection pressure on bsfc and exhaust emissions have been investigated. Experiments have been performed on a direct-injection turbocharged diesel engine. Emissions and bsfc values have been measured in 13 speed and load conditions based on ECE-R49 test by changing injection pressure from 200 to 300 bars. Results show that higher injection pressure reduces HC and bsfc, due to better mixing that causes faster combustion. Also it is found that NOx and CO2 are not substantially changed by injection pressure. Smoke behaves differently due to injection pressure. This is because of injection pressure effect on ignition delay and exhaust temperature. These parameters effect re-burning soot at the late combustion phase. In term of emission control in turbocharged diesel engine, this research work proposes variable injection pressure instead of constant injection pressure. This situation is possible with electronic control units.

Keywords:

Diesel engine , Injection pressure , Exhaust emission , Brake specific fuel consumption(bsfc)