Mathias Rollwage

New Generation of BOSCH Electrical Fuel-Pumps - Improvement in Hot-Fuel Handling and Noise

This paper describes a new design of electrical fuel pumps for fuel injection systems. As fuel quality changed considerably in the last years, hot-fuel handling of pumps became insufficient and had to be improved. This was being achieved by connecting a hydro-dynamic pre-stage in series with the main pump unit which is of positive displacement type. Modern cars are highly sophisticated in engine noise reduction. Noise caused by pressure pulsation and body vibration of fuel pumps, having been concealed formerly in the total sound level, is audible now and has to be reduced. Solutions which have been put into practice will be shown and test results obtained on test bench and in cars are given in this paper.