A Study of Combustion Control Parameter Optimization in a Diesel Engine Using Cylinder Pressure

In diesel engine development, fuel consumption, emissions and combustion noise have been main development objectives for fuel economy, low emissions and NVH. These main objectives can be achieved with advanced engine technologies. As electronic actuating systems are widely applied on diesel engines, elaborate control is required. This is because the main development targets are greatly affected by engine control parameters but frequently have a trade-off relationship. Therefore, the optimization of combustion control parameters is one of the most challenging tasks for improvement. As an efficient method, the DOE methodology has been used in engine calibration. In order to develop a mathematical model, the input and output values must be measured. Unlike other variables, combustion noise has been continually reported to have better indication method in simplified way. In this paper, advanced noise index from cylinder pressure signal is applied on engine test. Its interactive relationship with fuel economy and emissions is explored and analyzed. The sensitivity of fuel consumption and emissions to combustion noise is quantified in a 1.6 passenger diesel engine. This analysis also provides whether there is critical parameter optimization of engine combustion control parameters. More properly balanced engine control strategies can be made by avoiding this critical parameter optimization.