Apparatus and methods of operating a combustion engine

Abstract

The present invention generally relates to dual chamber combustion engines. The invention particularly relates to apparatus and methods for ignition of ultra-lean fuel/air mixtures with fuel/air mixture streams traveling at supersonic velocities. Present invention will be impactful in emission reduction as well as improving fuel economy and thermal efficiency in engines.

1 . A supersonic ignition device comprising a supersonic nozzle, wherein the supersonic nozzle has a converging-diverging geometry and an area ratio between four and nine, and the length of the supersonic nozzle is 10-30 mm, and the supersonic nozzle is configured to be capable of igniting an ultra-lean fuel-air mixture. 
     
     
         2 . The supersonic ignition device of  claim 1 , wherein the length of the supersonic nozzle is 10-20 mm. 
     
     
         3 . The supersonic ignition device of  claim 1 , wherein the supersonic nozzle has a throat, wherein the throat has a diameter of 1.0-2.0 mm. 
     
     
         4 . A supersonic jet combustion engine comprising a pre-chamber, a supersonic nozzle with a length between 10-30 mm, and a main chamber, wherein the supersonic nozzle has a converging-diverging geometry and an area ratio between four and nine, wherein the supersonic jet combustion engine is configured to generate a jet of combustion products from a first fuel/air mixture in the pre-chamber, through the supersonic nozzle, and into the main chamber with at least supersonic velocity (at least Mach 1) to ignite a second fuel/air mixture in the main chamber. 
     
     
         5 . The supersonic jet combustion engine of  claim 4 , wherein the second fuel/air mixture is an ultra-lean fuel mixture with a fuel/air equivalence ratio of equal to or less than 0.4. 
     
     
         6 . The supersonic jet combustion engine of  claim 4 , wherein the second fuel/air mixture has a fuel/air equivalence ratio of 0.22-0.29. 
     
     
         7 . The supersonic jet combustion engine of  claim 4 , wherein the second fuel/air mixture has a fuel/air equivalence ratio of 0.22-0.23. 
     
     
         8 . The supersonic jet combustion engine of  claim 4 , wherein the supersonic nozzle has a length between 10-20 mm. 
     
     
         9 . The supersonic jet combustion engine of  claim 4 , wherein the supersonic nozzle has a throat, wherein the throat has a diameter of 1.0-2.0 mm. 
     
     
         10 . A method of operating a supersonic jet combustion engine, wherein the method comprises: a) igniting a first fuel/air mixture in a pre-chamber; b) introducing a jet of combustion products from the first fuel/air mixture from the pre-chamber, through a supersonic nozzle with a length between 10-30 mm, and into a main chamber with at least supersonic velocity (at least Mach 1), wherein the supersonic nozzle has a converging-diverging geometry and an area ratio between four and nine; wherein the jet with supersonic velocity causes combustion of a second fuel/air mixture in the main chamber, wherein the second fuel/air mixture is an ultra-lean fuel mixture with a fuel/air equivalence ratio of equal to or less than 0.4. 
     
     
         11 . The method of  claim 10 , wherein the second fuel/air mixture is an ultra-lean fuel mixture with a fuel/air equivalence ratio of 0.22-0.29. 
     
     
         12 . The method of  claim 10 , wherein the second fuel/air mixture is an ultra-lean fuel mixture with a fuel/air equivalence ratio of 0.22-0.23. 
     
     
         13 . The method of  claim 10 , wherein the supersonic nozzle has a length between 10-20 mm. 
     
     
         14 . The method of  claim 10 , wherein the fuel is hydrogen, gasoline or natural gas. 
     
     
         15 . The method of  claim 10 , wherein the fuel is hydrogen 
     
     
         16 . The method of  claim 10 , wherein the jet results in a Damkohler number of equal to or greater than 11. 
     
     
         17 . The method of  claim 10 , wherein the supersonic nozzle has a throat, wherein the throat has a diameter of 1.0-2.0 mm.