Development of a Single-Suction Double-Discharge Automatic Transmission Oil Pump for Power-Consumption Reduction

Abstract

The high power consumption of the automatic transmission oil pump has led to the undertaking of efficiency improvement studies over a number of decades. For the unique idea of the present paper, a single automatic transmission oil pump was adopted to satisfy the requirements of both the high- and low-pressure lines. A single-suction double-discharge oil pump, which has two separate discharge ports that are connected to the individual pressure lines, was developed for the elimination of any unnecessary power consumption. The flow distribution ratio was analyzed according to the chamber volume ratio of the primary and secondary discharge sections. A single-suction double-discharge pump was designed using a flow analysis for which, design parameters such as the rotor diameter change and the eccentricity were utilized. A backpressure hole that is adjacent to the secondary discharge section drastically alleviated the internal pressure and the hydraulic torque in the pumping chambers. The power reduction effect of the oil pump prototype was compared with that of a conventional mechanical pump, and an experimental evaluation was conducted according to the operating conditions. The power reduction rate was estimated to be 16.5 %.