Seal for a rotary valve for an internal combustion engine

Abstract

A gas seal between a port ( 10, 12 ) of a rotary valve ( 7 ) and a port ( 8 ) in a combustion chamber ( 6 ) of a rotary valve engine, the seal comprising gas channel means ( 15 ) forming a turbo valve means ( 26 ) surrounding the port ( 8 ) in the combustion chamber and compression means ( 20, 21 ) for creating a pressure in the gas channel means greater than a pressure in the combustion chamber during a compression stroke and a power stroke of the engine.

1 . A gas seal system between a port of a rotary valve and a port in a combustion chamber of a rotary valve engine, the seal comprising gas channel means forming a turbo valve means surrounding the combustion chamber port and compression means for creating a pressure in the gas channel means greater than a pressure in the combustion chamber during a compression stroke and a power stroke of the engine. 
     
     
         2 . A gas seal system as claimed in  claim 1  wherein a clearance between the turbo valve means and an outer surface of the rotary valve is approximately 00254 mm (1 mil). 
     
     
         3 . A gas seal system as claimed in  claim 1 , wherein the compression means comprises a turbo valve injector means for injecting gas substantially tangentially into the turbo valve means. 
     
     
         4 . A gas seal system as claimed in  claim 3 , comprising position sensor means for sensing a rotational position of a rotor of the rotary valve for signaling to the compression means. 
     
     
         5 . A gas seal system as claimed in  claim 4 , comprising valve means for controlling admission of compressed gas from the compression means to the turbo valve injector means on receipt of signals from the sensor means. 
     
     
         6 . A gas seal system as claimed in  claim 1 , wherein the compression means comprises a compression chamber means. 
     
     
         7 . A gas seal system as claimed  claim 1 , wherein the compression means comprises compressor means driven by a crankshaft of the rotary valve engine. 
     
     
         8 . A gas seal system as claimed in  claim 1 , wherein the compression means comprises a crankcase of the engine pressurised by intake and power strokes of the engine. 
     
     
         9 . A gas seal system as claimed in  claim 8 , wherein the crankcase comprises a one-way valve means for admitting air into the crankcase on compression and exhaust strokes of the engine. 
     
     
         10 . A gas seal system as claimed in  claims 8 , comprising a non-return valve means for passing compressed air from the crankcase to the compression chamber means. 
     
     
         11 . A rotary valve engine comprising a gas seal as claimed in  claim 1 . 
     
     
         12 . A rotary valve engine as claimed in  claim 11 , wherein a rotor of the rotary valve is arranged to be cooled by passing water through a bore of the rotor. 
     
     
         13 . A method of providing a seal in a rotary valve engine between a port in the rotary valve and a port in a combustion chamber of the engine, comprising the steps of:
 a. providing a gas channel means forming a turbo valve means surrounding the combustion chamber port;   b. creating, with gas compression means, a pressure in the gas channel means greater than a pressure in the combustion chamber during a compression stroke and a power stroke of the engine.   
     
     
         14 . A method as claimed in  claim 13 , comprising injecting gas substantially tangentially into the turbo valve means with a turbo valve injector means. 
     
     
         15 . A method as claimed in  claims 13 , comprising sensing a rotational position of a rotor of the rotary valve with sensor means for signaling to the compression means. 
     
     
         16 . A method as claimed in  claim 14 , comprising controlling admission of compressed gas from the compression means to the turbo valve injector means on receipt of signals from the sensor means. 
     
     
         17 . A method as claimed in  claim 13 , wherein creating a pressure in the gas channel means comprises creating a pressure in a compression chamber means. 
     
     
         18 . A method as claimed in  claim 13 , wherein creating a pressure in the gas channel means comprises creating a pressure with a compressor means driven by a crankshaft of the rotary valve engine. 
     
     
         19 . A method as claimed in  claim 13 , wherein creating a pressure in the gas channel means comprises pressurising air in a crankcase of the engine by intake and power strokes of the engine. 
     
     
         20 . A method as claimed in  claim 19 , wherein pressurising air in the crankcase, comprises admitting air into the crankcase through a one-way valve means on compression and exhaust strokes of the engine. 
     
     
         21 . A method as claimed in  claim 17 , wherein creating a pressure in the gas channel means comprises passing compressed air from the crankcase to the compression chamber means through pneumatic tubing means and a non-return valve means.