Simulation And Test Research On Fuel Pressure Pulsation Noise In A Vehicle

The fuel injection can’t be accurately controlled because of fuel pulsation, which has bad effect on the surrounding and emission. What’s more, the noise resulted from fuel pulsation is one major part of the vehicle idle noise. With the increasingly strict regulation of noise and fuel consumption, research for fuel pulsation is becoming very important during vehicle performance developing. The fuel pulsation noise was found for a passenger car at hot idle speed. And factors effecting the fuel pulsation and correlated noise were studied through simulation and test.The principle of fuel pulsation was explained by introduction of the “water hammer effect”. A mathematical model was created to describe the effect on fuel pulsation and the equations between fuel flow velocity, fuel volume modulus, density, wall thickness and inner diameter of fuel pipe were listed. As the fuel pulsation was the noise source, if the transfer path of this noise source was constant, the analysis for the correlation between fuel pressure pulsation and vehicle idle noise was available.Several optimized structures were used to decrease the fuel pressure pulsation. Pressure spread in fuel rails with different sections and inner dampers was simulated by three dimension CFD software, which showing that the higher of the aspect ratio, the lower of the fuel pressure pulsation. Pressure spread in the fuel system including different pipes and out dampers was also simulated in one dimension CFD software, which showing that decrease of the pipe elasticity, increase of the pipe length and out dampers could depress the fuel pressure pulsation.Based on the simulation, rectangle fuel rail, circular fuel rail with inner damper, rubber pipe, out damper were made and assembled in vehicle to test the fuel pressure and idle noise. The improvement of noise for different variants was detailed and cooperated with the layout, cost and time. The best scheme was chosen to manufacture.The vehicle idle noise resulted from fuel system was solved by simulation of fuel pressure pulsation and test of vehicle idle noise. The studying method and conclusion could be used to depress fuel pressure pulsation and solve similar vehicle idle noise.