Brushless Motors for In-Tank Fuel Pumps

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.