Study on optimization method of GDI engine combustion noise based on noise-performance map

An optimization of GDI engine combustion noise was evaluated through experimental and simulation methods. First, finite element model of engine was established; the vibration response and combustion noise caused by combustion incentives were calculated by the direct frequency response method and the acoustic transfer vector method. Above of this, the pure combustion noise attenuation curve was defined. According to the combustion spectrum calculated, the optimized frequency range was determined. Then, combining with the analysis result of the combustion noise attenuation curve, the frequency position of cylinder pressure spectrum to be optimized was obtained. Besides this, the combustion parameters were measured through test and its relationship to cylinder pressure spectrum and engine power performance was studied, the noise-performance map was established. Based on optimized cylinder pressure spectrum and noise-performance map, the optimum values of combustion parameter were marked very quickly. The results show that, when the fuel injection timing optimization value was used, combustion noise was reduced most by 6.4 dB in the range of 0â–“1000 Hz, while torque reduced only by 3.8 Nm, which achieved the goals of the favoring NVH performance and engine power performance.