Evaporative cooling technique to control the temperature of a vehicle driveline component

Abstract

A system for cooling vehicle driveline components, such as axles or wet disc brake assemblies utilizes evaporative cooling effects of liquid applied to an exterior surface on the housing. A liquid supply is coupled with an outlet and a controller determines when cooling is needed. Liquid is applied onto the housing from the outlet as cooling is needed. One example includes a plurality of fluid collectors on a portion of the housing exterior to increase the amount of liquid maintained on the housing to increase the evaporative cooling effect.

We claim:  
     
         1 . A system for controlling a temperature of a vehicle driveline component, comprising: 
 a housing that houses at least portions of the driveline component;    a supply of liquid supported on the vehicle;    an outlet coupled to the supply of liquid that is supported relative to the housing such that liquid from the outlet is applied onto the housing such that the liquid evaporates and operates to cool the component; and    a controller that determines when a temperature of the component is higher than a selected threshold and causes liquid from the supply to be applied to the housing through the outlet.    
     
     
         2 . The system of  claim 1 , including a temperature sensor that provides an indication of the temperature of the component to the controller.  
     
     
         3 . The system of  claim 2 , wherein the temperature sensor is positioned to provide an indication of the temperature of a lubricant within the housing.  
     
     
         4 . The system of  claim 1 , including a surface on the housing facing generally toward the outlet, the surface including at least one fluid collector that at least temporarily collects some of the fluid applied to the housing.  
     
     
         5 . The system of  claim 4 , including a plurality of fluid collectors.  
     
     
         6 . The system of  claim 5 , wherein the housing surface comprises a mesh that is secured to the housing.  
     
     
         7 . The system of  claim 6 , wherein the mesh comprises at least one of plastic or metal.  
     
     
         8 . The system of  claim 4 , wherein the surface comprises a coating applied to the housing in a pattern that includes at least one region where the coating is not applied or is thinner than other regions and wherein the at least one region forms the collector.  
     
     
         9 . The system of  claim 8 , wherein the coating comprises paint.  
     
     
         10 . The system of  claim 1 , wherein the outlet comprises an opening in a tube through which the liquid drips onto the housing.  
     
     
         11 . The system of  claim 1 , wherein the outlet comprises a misting nozzle through which the liquid is sprayed onto the housing.  
     
     
         12 . The system of  claim 1 , wherein the component comprises at least one of an axle assembly or a wet disc brake assembly or a combination of the axle assembly and the wet disc brake assembly.  
     
     
         13 . A method of cooling a vehicle driveline component that has a housing, comprising the steps of: 
 determining when a temperature of the component is above a chosen threshold; and    applying a liquid to the housing and allowing the liquid to evaporate to thereby cool the component.    
     
     
         14 . The method of  claim 13 , including dripping water onto the housing.  
     
     
         15 . The method of  claim 13 , including spraying a mist of water onto the housing.  
     
     
         16 . The method of  claim 13 , including providing a surface on the housing that includes a plurality of liquid collectors that at least temporarily collect the liquid applied the housing to thereby increase an amount of the liquid that evaporates off from the housing.