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In the current state of the art automotive fuel pumps there is only one channel on each side of the impeller. For high flow and pressure applications the size of such pumps becomes excessive. In order to reduce the size to a manageable level it may be necessary to have two or more channels on each side. But the problem with a multichannel pump is that the peak efficiency of each channel happens at a different operating point and the overall pump efficiency may not be that good. This problem can be overcome by synchronizing the channels. In a synchronous pump the channel diameter and cross sectional area of channels are such that the peak efficiency happens at the same operating point and the overall pump efficiency is improved. In this paper we derive the governing equations for flow, pressure and efficiency and layout a methodology for synchronizing the channels.

Traditional in-tank gasoline and diesel fuel pumps require high power, 120 W or more, in fuel systems that have high flow requirements, high pressure requirements, or both. One method to reduce power consumption is to improve efficiency by using a brushless motor rather than the traditional brush style motor. The brushless motor technology also eliminates the brush to commutator interface which improves the pump's robustness to fuel and reduces flow variation. Additional benefits are provided by the controller which provides motor commutation since it enables closed loop pump speed control, pump diagnostics, and the opportunity for additional sensor interfaces to improve the fuel delivery system architecture. This paper describes the brushless motor technology, design optimization strategy for fuel pump applications, selected design, and resulting torque and efficiency performance improvements.