Cooling systems for rotary engines

Abstract

Cooling systems for rotary internal combustion engines. Air through-rotor cooling is provided by a closed-loop cooling system with an output shaft-driven fan. Liquid cooling is provided utilizing a cooling chamber within the output shaft.

We claim: 
     
         1 . A rotary internal combustion engine, comprising
 a closed-loop cooling system having a closed-loop fluid flow path through the interior of a rotor of the engine and a heat exchanger; and   a fan configured to circulate a fluid around the flow path,   wherein the fan is mounted on and driven directly by the engine's output shaft.   
     
     
         2 . An engine according to  claim 1 , wherein the fluid is a gas. 
     
     
         3 . An engine according to  claim 2 , wherein the gas is gas which has blown-past the rotor's side-seals. 
     
     
         4 . An engine according to  claim 1 , wherein the fan is a centrifugal fan. 
     
     
         5 . An engine according to  claim 1 , wherein the fan has a diameter of 160 mm or greater. 
     
     
         6 . An engine according to  claim 1 , wherein the closed-loop cooling system comprises a pressure-relief valve configured to limit the maximum pressure in the closed-loop fluid flow path. 
     
     
         7 . An engine according to  claim 1 , wherein the closed-loop cooling system comprises an oil injector for injecting oil into gas flowing in the closed-loop fluid flow path for lubricating the interior of the rotor. 
     
     
         8 . An engine according to  claim 7  when dependent on  claim 6 , wherein a vent outlet of the pressure-relief valve is fluidly coupled to a reservoir of the oil injector. 
     
     
         9 . A rotary internal combustion engine, comprising
 an output shaft having an internal cooling chamber with a closed distal end within the output shaft, and an open proximal end at an end of the output shaft;   a tube within the cooling chamber spaced from the internal wall of the cooling chamber and from the distal end of the cooling chamber, the tube and cooling chamber forming a cooling flow-path through the centre of the tube, between the end of the tube and the distal end of the cooling chamber, and between the exterior surface of the tube and the interior surface of the cooling chamber; and   an impeller for circulating water through the cooling flow-path.   
     
     
         10 . An engine according to  claim 9 , wherein the tube is stationary with respect to the engine body. 
     
     
         11 . An engine according to  claim 9 , wherein the impeller is mounted on the open end of the output shaft. 
     
     
         12 . An engine according to any of  claims 9  wherein the exterior surface of the tube is spaced from the interior surface of the cooling chamber by 2 mm or more.