High-efficiency linear combustion engine

Abstract

Various embodiments of the present invention are directed toward a linear combustion engine, comprising: a cylinder having a cylinder wall and a pair of ends, the cylinder including a combustion section disposed in a center portion of the cylinder; a pair of opposed piston assemblies adapted to move linearly within the cylinder, each piston assembly disposed on one side of the combustion section opposite the other piston assembly, each piston assembly including a spring rod and a piston comprising a solid front section adjacent the combustion section and a gas section; and a pair of linear electromagnetic machines adapted to directly convert kinetic energy of the piston assembly into electrical energy, and adapted to directly convert electrical energy into kinetic energy of the piston assembly for providing compression work during the compression stroke.

1 - 45 . (canceled) 
     
     
         46 . A linear combustion engine, comprising:
 a cylinder comprising:
 a combustion section, and 
 a driver section comprising a compression mechanism that is configured to provide at least some compression work during a compression stroke of the engine; 
   a piston assembly disposed adjacent to the combustion section, the piston assembly configured to move linearly;   a linear electromagnetic machine disposed outside of the cylinder, wherein the linear electromagnetic machine is configured to directly convert kinetic energy of the piston assembly into electrical energy, and configured to directly convert electrical energy into kinetic energy of the piston assembly;   wherein the engine has a variable expansion ratio greater than 50:1.   
     
     
         47 . The linear combustion engine of  claim 46 , wherein the engine has a variable compression ratio less than or equal to the variable expansion ratio. 
     
     
         48 . The linear combustion engine of  claim 46 , wherein a length of the combustion section at top-dead-center is between 0.1 inches and 2 inches. 
     
     
         49 . The linear combustion engine of  claim 46 , wherein the piston assembly comprises:
 a piston;   one or more piston seals coupled to the piston; and   a piston rod coupled to the piston, wherein the piston rod is configured to move linearly inside and outside of the cylinder.   
     
     
         50 . The linear combustion engine of  claim 49 , wherein the piston rod is further configured to move along bearings and is sealed by a gas seal that is fixed to the cylinder. 
     
     
         51 . The linear combustion engine of  claim 46 , wherein the piston assembly comprises:
 two pistons;   one or more piston seals coupled to each of the two pistons; and   a piston rod coupled to the two pistons;   wherein the piston assembly is encapsulated by the cylinder and configured to move linearly within the cylinder.   
     
     
         52 . The linear combustion engine of  claim 46 , wherein the linear electromagnetic machine comprises:
 a stator; and   a translator attached to the piston assembly that moves linearly within the stator.   
     
     
         53 . The linear combustion engine of  claim 46 , wherein the linear electromagnetic machine is selected from the group consisting of a permanent magnet machine, an induction machine, a switched reluctance machine, and a combination thereof. 
     
     
         54 . The linear combustion engine of  claim 46 , wherein the compression mechanism comprises a gas spring comprising a volume of gas located in the driver section. 
     
     
         55 . The linear combustion engine of  claim 54 , further comprising one or more driver gas exchange ports configured to allow for an exchange of gas in the driver section. 
     
     
         56 . The linear combustion engine of  claim 46 , wherein the linear electromagnetic machine is configured to apply an electromagnetic force to the piston assembly for providing compression work during the compression stroke. 
     
     
         57 . The linear combustion engine of  claim 46 , further comprising an injector configured to inject fuel. 
     
     
         58 . The linear combustion engine of  claim 57 , wherein the injector is configured to inject fuel directly into the combustion section. 
     
     
         59 . The linear combustion engine of  claim 57 , wherein the injector is configured to inject fuel into an intake port. 
     
     
         60 . The linear combustion engine of  claim 46 , further comprising one or more exhaust ports configured to allow exhaust gases to leave the cylinder. 
     
     
         61 . The linear combustion engine of  claim 46 , wherein the engine operates using a two-stroke piston cycle including a power stroke and the compression stroke. 
     
     
         62 . The linear combustion engine of  claim 46 , wherein during a power stroke of the engine, a portion of the kinetic energy of the piston assembly is converted into electrical energy by the linear electromagnetic machine and another portion of the kinetic energy does compression work on the driver section. 
     
     
         63 . The linear combustion engine of  claim 46 , wherein the engine operates using a four-stroke piston cycle including an intake stroke, the compression stroke, a power stroke, and an exhaust stroke. 
     
     
         64 . The linear combustion engine of  claim 46 , wherein the combustion section is configured to achieve compression ignition. 
     
     
         65 . The linear combustion engine of  claim 46 , wherein the combustion section is configured to achieve spark ignition. 
     
     
         66 . The linear combustion engine of  claim 46 , further comprising one or more injector ports configured to allow fluids to enter the cylinder. 
     
     
         67 . The linear combustion engine of claim  1 , further comprising one or more intakes configured to allow an intake into the cylinder, the intake comprising at least one of air, air and fuel mixtures, and mixtures of air and at least one of fuel and combustion products. 
     
     
         68 . A linear combustion engine, comprising:
 a first cylinder comprising a combustion section;   a second cylinder comprising a compression mechanism that is configured to provide at least some compression work during a compression stroke of the engine;   a piston assembly disposed adjacent to the combustion section, the piston assembly configured to move linearly; and   a linear electromagnetic machine disposed between the first cylinder and the second cylinder, wherein the linear electromagnetic machine is configured to directly convert kinetic energy of the piston assembly into electrical energy, and configured to directly convert electrical energy into kinetic energy of the piston assembly.   
     
     
         69 . The linear combustion engine of  claim 68 , wherein the engine has a variable compression ratio less than or equal to a variable expansion ratio. 
     
     
         70 . The linear combustion engine of  claim 68 , wherein a length of the combustion section at top-dead-center is between 0.1 inches and 2 inches. 
     
     
         71 . The linear combustion engine of  claim 68 , wherein the piston assembly comprises:
 two pistons;   two or more piston seals; and   a piston rod configured to move linearly between the first cylinder and the second cylinder.   
     
     
         72 . The linear combustion engine of claim  26 , wherein the piston rod is further configured to move along bearings and is sealed by a gas seal that is fixed to the first cylinder. 
     
     
         73 . The linear combustion engine of  claim 68 , wherein the linear electromagnetic machine comprises:
 a stator; and   a translator attached to the piston assembly configured to move linearly within the stator.   
     
     
         74 . The linear combustion engine of  claim 68 , wherein the linear electromagnetic machine is selected from the group consisting of a permanent magnet machine, an induction machine, a switched reluctance machine, and a combination thereof. 
     
     
         75 . The linear combustion engine of  claim 68 , wherein the compression mechanism comprises a gas spring comprising a volume of gas located in a driver section of the second cylinder. 
     
     
         76 . The linear combustion engine of  claim 68 , further comprising one or more driver gas exchange ports configured to allow for an exchange of gas in the driver section. 
     
     
         77 . The linear combustion engine of  claim 68 , wherein the linear electromagnetic machine is configured to apply an electromagnetic force to the piston assembly for providing compression work during the compression stroke. 
     
     
         78 . The linear combustion engine of  1   claim 68 , further comprising an injector configured to inject fuel. 
     
     
         79 . The linear combustion engine of  claim 78 , wherein the injector is configured to inject fuel directly into the combustion section. 
     
     
         80 . The linear combustion engine of  claim 78 , wherein the injector is configured to inject fuel into an intake port. 
     
     
         81 . The linear combustion engine of  claim 68 , further comprising one or more exhaust ports configured to allow exhaust gases to leave the first cylinder. 
     
     
         82 . The linear combustion engine of  claim 68 , wherein during a power stroke of the engine, a portion of the kinetic energy of the piston assembly is converted into electrical energy by the linear electromagnetic machine and another portion of the kinetic energy does compression work on a driver section of the second cylinder. 
     
     
         83 . The linear combustion engine of  claim 68 , wherein the engine operates using a four-stroke piston cycle including an intake stroke, the compression stroke, a power stroke, and an exhaust stroke. 
     
     
         84 . The linear combustion engine of  claim 68 , wherein the combustion section is configured to achieve compression ignition. 
     
     
         85 . The linear combustion engine of  claim 68 , wherein the combustion section is configured to achieve spark ignition. 
     
     
         86 . The linear combustion engine of  claim 68 , further comprising one or more injector ports configured to allow a fluid to enter the first cylinder. 
     
     
         87 . The linear combustion engine of  claim 68 , further comprising one or more intakes configured to allow an intake into the first cylinder, the intake comprising at least one of air, air and fuel mixtures, and mixtures of air and at least one of fuel and combustion products.