A Case Study on Reducing the Fuel Pulse Noise from Gasoline Engine Injectors 2020-01-1276
Vehicle NVH performance is a very important consideration for vehicle buyers in the marketplace. There are many noise sources from the fuel system to generate noise in a vehicle. Among them, the pressure pulsations due to the rapid opening and closing of gasoline engine injectors can cause undesirable fuel pulse noise inside the vehicle cabin. As the pressure pulsation propagates in the fuel supply line toward to rear end of the vehicle, the pressure energy is transferred from fuel lines to the vehicle underbody through clips and into the passenger compartment. It is crucial to attenuate the pressure pulsation inside the fuel line to reduce the fuel pulse noise. In this paper, a case study on developing an effective countermeasure to reduce the objectionable fuel pulse noise of a V8 gasoline injection system is presented.
First, the initial interior noise of a prototype vehicle was tested and the objectionable fuel pulse noise was exhibited. The problem frequency ranges with pulse and ticking noise content were identified. Several test iterations on root causing analysis and countermeasures development were performed. It was found that adding the expansion chamber in the fuel line is an efficient countermeasure to reduce the fuel pulse noise in the problem frequency range. Then, a one-dimensional(1D) GT-Power simulation model of the full fuel system is developed to analyze the wave dynamic behavior of pressure pulsation in the fuel line. The expansion chamber design in the initial test was evaluated by the simulation model and good correlations are obtained between the simulation and the test results. Finally, based on the package space, several expansion design iterations were analyzed and compared by the correlated simulation model. The final expansion chamber design which reduced the pulsation most effectively and also met the package requirements was recommended to build. The interior noise with the suggest design in the fuel line was tested and the results showed that the fuel pulse noise in the vehicle was reduced to accept level.
From this study, it is concluded that proper countermeasures need be implemented to attenuate the fuel pulse in problem frequency ranges. An accurate simulation model can be used to evaluate different technologies to reduce the pressure pulsation in the fuel line and assist developing timely NVH solutions for a production launch of a vehicle.
Weiguo Zhang, Toon Tan, John Malicki, Glenn Whitehead