Internal combustion engine

Abstract

Improved internal combustion engine, particularly, an improved two-stroke, diesel aircraft engine. A first improvement includes a wrist pin/connection rod assembly. A plurality of fasteners extend through a wall of a wrist pin and into a wrist pin insert to secure the wrist pin to a cradle-like portion of a connecting rod. A second improvement includes a fuel injection system which cools fuel injectors with overflow fuel from a fuel pump. The overflow fuel is warmed as it cools the fuel injectors, thereby preventing ice-build up on a fuel filter in cold weather as the overflow fuel is recirculated to the fuel pump. A third improvement includes a new cylinder head cooling arrangement. The cylinder head and a cooling cap define an annular cooling passageway. Cooling fluid flows through the annular cooling passageway to cool the cylinder head. The cooling cap includes an inlet port and an outlet port which are not diametrically opposed. Accordingly, the annular cooling passageway includes a restricted portion to ensure cooling fluid flows completely around the annular cooling passageway to better cool the cylinder head. The cooling cap is adjustably mounted on the cylinder head, so that the cooling cap can be coupled to a cooling jacket independent of the location of the cylinder head on the engine or cylinder block, as when the cylinder head threads into the engine block. The same clamping device used to connect the cooling cap to the cylinder head can be used to secure the fuel injector to the cylinder head. A fourth improvement includes a cross-feed cooling passageway extending between multiple cylinder banks to provide thermal coupling between the cylinder heads and the lower crankcase of the engine, and to provide a safety arrangement for continued cooling fluid flow at least in the event a thermostat in communication with a cooling jacket should fail.

1. An internal combustion engine, comprising:
 an engine block at least partially defining a cylinder;  
 a piston reciprocally operable within said cylinder;  
 a cylinder head cooperating with said cylinder and said piston to define a combustion chamber; and  
 a fuel injection system including: 
 a fuel injector for injecting fuel into said combustion chamber, said fuel injector having a fuel inlet port, a fuel outlet port, a fuel passage communicating between said fuel inlet port and said fuel outlet port, a cooling fuel inlet port, a leak-of fuel outlet port, and a cooling fuel passage communicating between said cooling fuel inlet port and said leak-off fuel outlet port;  
 a fuel pump;  
 a fuel supply line communicating between said fuel pump and said fuel inlet port;  
 a bypass fuel line communicating between said fuel pump and said cooling fuel inlet port, such that all overflow fuel from said fuel pump flows through said bypass fuel line, into said cooling fuel inlet port, through said cooling fuel passage and out of said leak-off fuel outlet port, thereby cooling said fuel injector, wherein all of the overflow fuel is recirculated from said leak-off fuel outlet port back to said fuel pump; and  
 a fuel filter placed upstream of said fuel pump such that the overflow fuel recirculated to said fuel pump flows through said fuel filter prior to reaching said fuel pump, and such that the overflow fuel which cools said fuel injector is warmed as it flows through said fuel injector, thereby heating the fuel which flows through said fuel filter to substantially prevent ice build-up on said fuel filter during cold weather.  
 
 
     
     
       2. An internal combustion engine according to  claim 1 , wherein said fuel injector includes a fuel injector body which includes said fuel inlet port, said cooling fuel inlet port and said leak-off fuel outlet port. 
     
     
       3. An internal combustion engine according to  claim 2 , wherein said fuel injector further includes a fuel injector nut, such that said fuel injector body threads into said fuel injector nut, and such that said cooling fuel passage includes a space within said fuel injector nut, so that the overflow fuel commingles with leak-off fuel in said space and exits with leak-off fuel out of said leak-off fuel outlet port. 
     
     
       4. An internal combustion engine according to  claim 1 , where said engine is a two-stroke, diesel aircraft engine. 
     
     
       5. An internal combustion engine according to  claim 3 , wherein said cooling fuel passage also includes, in said fuel injector body, an upstream portion between said cooling fuel inlet port and said space, and a downstream portion between said space and said leak-off fuel outlet port. 
     
     
       6. A two-stroke, diesel aircraft engine comprising:
 an engine block at least partially defining a cylinder;    a piston reciprocally operable within said cylinder;    a cylinder head cooperating with said cylinder and said piston to define a combustion chamber; and    a fuel injection system including: 
 a fuel injector for injecting fuel into said combustion chamber, said fuel injector including a fuel injector nut, and a fuel injector body threaded into said fuel injector nut so as to define within said fuel injector nut a space into which leak-off fuel normally flows, said fuel injector body having therein a fuel inlet port, a cooling fuel inlet port, a leak-off fuel outlet port, an upstream cooling fuel passage portion between said cooling fuel inlet port and said space, and a downstream cooling fuel passage portion between said space and said leak-off fuel outlet port, and said fuel injector also including a fuel outlet port, and a fuel passage communicating between said fuel inlet port and said fuel outlet port;  
 a fuel pump;  
 a fuel supply line communicating between said fuel pump and said fuel inlet port;  
 a bypass fuel line communicating between said fuel pump and said cooling fuel inlet port, such that overflow fuel from said fuel pump flows through said bypass fuel line, into said cooling fuel inlet port, through said upstream cooling fuel passage portion and into said space, where the overflow fuel commingles with leak-off fuel in said space, through said downstream cooling fuel passage portion and out of said leak-off fuel outlet port, thereby cooling said fuel injector; and  
 a fuel return line conducting the overflow fuel from said leak-off fuel outlet port back to said fuel pump.  
   
     
     
       7. An engine according to  claim 6 , wherein said fuel injection system further includes a fuel filter in said fuel return line upstream of said fuel pump such that the overflow fuel flows through said fuel filter prior to reaching said fuel pump, and such that the overflow fuel which cools said fuel injector is warmed by said fuel injector, thereby resisting ice build-up on said fuel filter during cold weather. 
     
     
       8. An internal combustion engine according to  claim 1 , wherein said fuel injection system includes a fuel supply tank and a return fuel tank in fluid communication with the fuel supply tank, and wherein all of the overflow fuel is recirculated from said leak- off fuel outlet port, through said return fuel tank, and back to said fuel pump.   
     
     
       9. An internal combustion engine according to  claim 8 , further comprising a fuel return line conducting all of the overflow fuel from said leak- off fuel outlet port back to said return fuel tank.   
     
     
       10. An internal combustion engine, comprising:
   an engine block at least partially defining a cylinder;        a piston reciprocally operable within said cylinder;        a cylinder head cooperating with said cylinder and said piston to define a combustion chamber; and        a fuel injection system including:      a fuel supply tank;        a return fuel tank in fluid communication with the fuel supply tank;        a fuel injector for injecting fuel into said combustion chamber, said fuel injector having a fuel inlet port, a fuel outlet port, a fuel passage communicating between said fuel inlet port and said fuel outlet port, a cooling fuel inlet port, a leak - off fuel outlet port, and a cooling fuel passage communicating between said cooling fuel inlet port and said leak - off fuel outlet port;        a fuel pump;        a fuel supply line communicating between said fuel pump and said fuel inlet port;        a bypass fuel line communicating between said fuel pump and said cooling fuel inlet port, such that overflow fuel from said fuel pump flows through said bypass fuel line, into said cooling fuel inlet port, through said cooling fuel passage and out of said leak - off fuel outlet port, thereby cooling said fuel injector, wherein the overflow fuel is recirculated from said leak - off fuel outlet port, through said return fuel tank, and back to said fuel pump.       
     
     
       11. An internal combustion engine according to  claim 10 , further comprising a fuel filter placed upstream of said fuel pump such that the overflow fuel recirculated to said fuel pump flows through said return fuel tank and said fuel filter prior to reaching said fuel pump, and such that the overflow fuel which cools said fuel injector is warmed as it flows through said fuel injector, thereby heating the fuel which flows through said fuel filter to substantially prevent ice build- up on said fuel filter during cold weather.   
     
     
       12. An internal combustion engine according to  claim 10 , wherein said fuel injector includes a fuel injector body which includes said fuel inlet port, said cooling fuel inlet port and said leak- off fuel outlet port.   
     
     
       13. An internal combustion engine according to  claim 12 , wherein said fuel injector further includes a fuel injector nut, such that said fuel injector body threads into said fuel injector nut, and such that said cooling fuel passage includes a space within said fuel injector nut, so that the overflow fuel commingles with leak- off fuel in said space and exits with leak - off fuel out of said leak - off fuel outlet port.   
     
     
       14. An internal combustion engine according to  claim 13 , wherein said cooling fuel passage also includes, in said fuel injector body, an upstream portion between said cooling fuel inlet port and said space, and a downstream portion between said space and said leak- off fuel outlet port.   
     
     
       15. An internal combustion engine according to  claim 10 , where said engine is a two- stroke, diesel aircraft engine.   
     
     
       16. An internal combustion engine according to  claim 10 , further comprising a fuel return line conducting the overflow fuel from said leak- off fuel outlet port back to said return fuel tank.