Transmission system for an electric vehicle

Abstract

A transmission system for an electric vehicle. The system includes a gearbox containing gears and a lubricating fluid. A pump is provided for supplying and removing lubricating fluid from the gear box. The operation of the pump is controlled by a controller. A reservoir is provided for storing lubricating fluid. The controller is configured to control the pump so that a portion of the lubricating fluid is removed from the gear box when the vehicle is involved in a high acceleration event.

What is claimed is: 
     
         1 . A transmission system for an electric vehicle comprising:
 a gearbox containing gears and a lubricating fluid;   a pump for supplying and removing lubricating fluid from the gear box, wherein operation of the pump is controlled by a controller;   a reservoir for storing lubricating fluid;   wherein controller is configured to control the pump so that a portion of the lubricating fluid is transferred from the reservoir toward the gear box when the vehicle is involved in a high acceleration event.   
     
     
         2 . The transmission system of  claim 1 , wherein the portion of the lubricating fluid is less than 100 ml. 
     
     
         3 . The transmission system of  claim 1 , wherein the portion of the lubricating fluid is about 50 ml. 
     
     
         4 . The transmission system of  claim 1 , further comprising a motor for driving the pump. 
     
     
         5 . The transmission system of  claim 4 , wherein the controller directly controls the operation of the motor to thereby control the operation of the pump. 
     
     
         6 . The transmission system of  claim 1 , wherein the controller is connected to a vehicle data communication bus, and wherein the data communication bus carries data confirming the existence of the high acceleration event to the controller. 
     
     
         7 . The transmission system of  claim 1 , wherein the controller is connected to a vehicle data communication bus, and wherein the data communication bus carries data regarding the condition of a plurality of vehicle components; and wherein the controller is configured to determine whether a the high acceleration event exists based on the condition of at least one of the plurality of the vehicle components. 
     
     
         8 . The system of  claim 1 , wherein the controller is configured to control the pump to transfer the lubricating fluid from the reservoir when the vehicle's acceleration exceeds a first predetermined set point. 
     
     
         9 . The system of  claim 1 , wherein the first predetermined set point is at least 1.2 G. 
     
     
         10 . The system of  claim 8 , wherein the controller is configured to control the pump to transfer the fluid into the reservoir after the high acceleration event when the vehicle's acceleration reduces to a value less than a second predetermined set point. 
     
     
         11 . The system of  claim 10 , wherein the second predetermined set point is less than or equal to 0.5 G. 
     
     
         12 . A transmission system for an electric vehicle comprising:
 a gearbox containing gears and a lubricating fluid;   a reservoir for storing lubricating fluid;   a pump for moving lubricating fluid into and out of the reservoir, wherein operation of the pump is controlled by a controller;   wherein controller is configured to control the pump so that a portion of the lubricating fluid is transferred into or out of the reservoir based on the acceleration of the vehicle.   
     
     
         13 . The system of  claim 12 , wherein the lubricating fluid is transferred out of the reservoir toward the gear box when a value for the acceleration of the vehicle rises above a first predetermined set point. 
     
     
         14 . The system of  claim 13 , wherein the first predetermined set point is 1.2 G. 
     
     
         15 . The system of  claim 12 , wherein the lubricating fluid is transferred into the reservoir when a value for the acceleration of the vehicle decreases below a second predetermined set point. 
     
     
         16 . The system of  claim 15 , wherein the second predetermined set point is 0.5 G. 
     
     
         17 . The system of  claim 12 , wherein the controller is connected to a vehicle data communication bus, and wherein the data communication bus carries data regarding the condition of a plurality of vehicle components; and wherein the controller is configured to determine the acceleration of the vehicle based on the condition of at least one of the plurality of the vehicle components. 
     
     
         18 . A method of operating a transmission system for an electric vehicle, wherein the system includes a gearbox containing gears and a lubricating fluid and a pump for transferring fluid into and out of a reservoir that stores the lubricating fluid, the method comprising the steps of:
 operating the pump so that the lubricating fluid is transferred into or out of the reservoir based on the acceleration of the vehicle.   
     
     
         19 . The method of  claim 18 , wherein the lubricating fluid is transferred out of the reservoir toward the gear box when a value for the acceleration of the vehicle rises above a first predetermined set point. 
     
     
         20 . The method of  claim 18 , wherein the lubricating fluid is transferred into the reservoir when a value for the acceleration of the vehicle decreases below a second predetermined set point.