Transmission fluid pump speed control systems and methods

Abstract

A transmission fluid pump control system of a vehicle includes a target speed module and a speed control module. The target speed module determines a target speed of an electric transmission fluid pump based on a target output flowrate of the electric transmission fluid pump, a predetermined maximum allowable amount of leakage of transmission fluid pumps, and an efficiency of the electric transmission fluid pump. The speed control module applies power to the electric transmission fluid pump based on the target speed.

What is claimed is: 
     
         1 . A transmission fluid pump control system of a vehicle, comprising:
 a target speed module that determines a target speed of an electric transmission fluid pump based on a target output flowrate of the electric transmission fluid pump, a predetermined maximum allowable amount of leakage of transmission fluid pumps, and an efficiency of the electric transmission fluid pump; and   a speed control module that applies power to the electric transmission fluid pump based on the target speed.   
     
     
         2 . The transmission fluid pump control system of  claim 1  wherein the target speed module determines the target speed of the electric transmission fluid pump further based on a displacement of the electric transmission fluid pump. 
     
     
         3 . The transmission fluid pump control system of  claim 2  wherein the target speed module sets the target speed equal to a sum divided by the displacement and sets the sum based on the target output flowrate plus a product of the predetermined maximum allowable amount of leakage and the efficiency. 
     
     
         4 . The transmission fluid pump control system of  claim 2  wherein the target speed module sets the target speed equal to a sum divided by the displacement and sets the sum based on the target output flowrate plus the predetermined maximum allowable amount of leakage plus the efficiency. 
     
     
         5 . The transmission fluid pump control system of  claim 1  further comprising an efficiency module that determines the efficiency of the electric transmission fluid pump based on a speed determined for the electric transmission fluid pump and a predetermined speed for transmission fluid pumps having the predetermined maximum allowable amount of leakage. 
     
     
         6 . The transmission fluid pump control system of  claim 5  wherein the efficiency module sets the efficiency of the electric transmission fluid pump equal to the speed determined for the electric transmission fluid pump divided by the predetermined speed. 
     
     
         7 . The transmission fluid pump control system of  claim 5  further comprising a speed determination module that determines the speed for the electric transmission fluid pump based on a pressure of transmission fluid measured using a transmission fluid sensor. 
     
     
         8 . The transmission fluid pump control system of  claim 7  wherein the speed determination module sets the speed for the electric transmission fluid pump equal to a present speed when a decrease in the pressure is greater than a predetermined pressure. 
     
     
         9 . The transmission fluid pump control system of  claim 1  wherein the target speed module determines the predetermined maximum allowable amount of leakage based on a temperature of transmission fluid and a pressure of the transmission fluid. 
     
     
         10 . The transmission fluid pump control system of  claim 1  further comprising a target flowrate module that determines the target output flowrate of the electric transmission fluid pump based on a target output pressure of the electric transmission fluid pump. 
     
     
         11 . A transmission fluid pump control method for a vehicle, comprising:
 determining a target speed of an electric transmission fluid pump based on a target output flowrate of the electric transmission fluid pump, a predetermined maximum allowable amount of leakage of transmission fluid pumps, and an efficiency of the electric transmission fluid pump; and   applying power to the electric transmission fluid pump based on the target speed.   
     
     
         12 . The transmission fluid pump control method of  claim 11  further comprising determining the target speed of the electric transmission fluid pump further based on a displacement of the electric transmission fluid pump. 
     
     
         13 . The transmission fluid pump control method of  claim 12  further comprising:
 setting the target speed equal to a sum divided by the displacement; and 
 setting the sum based on the target output flowrate plus a product of the predetermined maximum allowable amount of leakage and the efficiency. 
 
     
     
         14 . The transmission fluid pump control method of  claim 12  further comprising:
 setting the target speed equal to a sum divided by the displacement; and 
 setting the sum based on the target output flowrate plus the predetermined maximum allowable amount of leakage plus the efficiency. 
 
     
     
         15 . The transmission fluid pump control method of  claim 11  further comprising determining the efficiency of the electric transmission fluid pump based on a speed determined for the electric transmission fluid pump and a predetermined speed for transmission fluid pumps having the predetermined maximum allowable amount of leakage. 
     
     
         16 . The transmission fluid pump control method of  claim 15  further comprising setting the efficiency of the electric transmission fluid pump equal to the speed determined for the electric transmission fluid pump divided by the predetermined speed. 
     
     
         17 . The transmission fluid pump control method of  claim 15  further comprising determining the speed for the electric transmission fluid pump based on a pressure of transmission fluid measured using a transmission fluid sensor. 
     
     
         18 . The transmission fluid pump control method of  claim 17  further comprising setting the speed for the electric transmission fluid pump equal to a present speed when a decrease in the pressure is greater than a predetermined pressure. 
     
     
         19 . The transmission fluid pump control method of  claim 11  further comprising determining the predetermined maximum allowable amount of leakage based on a temperature of transmission fluid and a pressure of the transmission fluid. 
     
     
         20 . The transmission fluid pump control method of  claim 11  further comprising determining the target output flowrate of the electric transmission fluid pump based on a target output pressure of the electric transmission fluid pump.