Internal combustion engine and working cycle

Abstract

The invention is concerned with a method of deriving mechanical work from a combustion gas in internal combustion engines and reciprocating internal combustion engines for carrying out the method. The invention includes methods and apparatuses for managing combustion charge densities, temperatures, pressures and turbulence in order to produce a true mastery within the power cylinder in order to increase fuel economy, power, and torque while minimizing. polluting emissions. In its preferred embodiments, the method includes the steps of (i) producing an air charge, (ii) controlling the temperature, density and pressure of the air charge, (iii) transferring the air charge to a power cylinder of the engine such that an air charge having a weight and density selected from a range of weight and density levels ranging from below atmospheric weight and density to heavier-than-atmospheric weight and density is introduced into the power cylinder, and (iv) then compressing the air charge at a lower-than-normal compression ratio, (v) causing a pre-determined quantity of charge-air and fuel to produce a combustible mixture, (vi) causing the mixture to be ignited within the power cylinder and (vii) allowing the combustion gas to expand against a piston operable in the power cylinders with the expansion ratio of the power cylinders being substantially greater than the compression ratio of the power cylinders of the engine. In addition to other advantages, the invented method is capable of producing mean effective cylinder pressures ranging from lower-than-normal to higher-than-normal. In the preferred embodiments, the mean effective cylinder pressure is selectively variable (and selectively varied) throughout the mentioned range during the operation of the engine. In an alternate embodiment related to constant speed-constant load operation, the mean effective cylinder pressure is selected from the range and the engine is configured, in accordance with the present invention, such that the mean effective cylinder pressure range is limited, being varied only in the amount required for producing the power, torque and speed of the duty cycle for which the engine is designed.

1 . A four-stroke internal combustion engine including at least one cylinder and a piston:
 slidable in the cylinder and moving through a plurality of power cycles each involving an intake stroke, a compression stroke, an expansion stroke and an exhaust stroke, the piston and cylinder defining, at least in part, a chamber within the engine, said engine further comprising:   an air intake port and an exhaust port associated with the chamber;   an air intake valve controllably movable to open and close the air intake port;   at least one compressor being in fluid communication with atmosphere and with the air intake port;   a fuel supply system operable to controllably inject fuel into the chamber; and   a first controller configured to selectively operate the air intake valve to maintain the intake port open during a majority portion of the compression stroke of the piston, and   a second controller configured to introduce fuel into the chamber.   
   
   
       2 . The engine of  claim 1 , wherein the at least one compressor comprises a first compressor being in fluid communication with the air intake port and a second compressor being in fluid communication with atmosphere and the first compressor. 
   
   
       3 . The engine of  claim 2 , wherein at least one of said first compressor and said second compressor is coupled with a turbine of a turbocharger, said turbine being in fluid communication with the exhaust port. 
   
   
       4 . The engine of  claim 1 , wherein the fuel supply system includes a fuel injector assembly. 
   
   
       5 . The engine of  claim 1 , including means for cooling the air compressed by the at least one compressor. 
   
   
       6 . The engine of  claim 2 , including means for cooling the air compressed by the second compressor. 
   
   
       7 . The engine of  claim 6 , including means for cooling the air compressed by the first compressor. 
   
   
       8 . The engine of  claim 1 , wherein said variable valve mechanism is actuated electronically. 
   
   
       9 . The engine of  claim 2 , further including an air cooler between at least one of said first compressor and said second compressor and said air intake port. 
   
   
       10 . The engine of  claim 1 , further including a second air intake port controlled by a second air intake valve. 
   
   
       11 . The engine of  claim 10 , including a controller configured to open the second air intake port at a point which is at or after the end of said majority portion of the compression stroke and before the end of the compression stroke. 
   
   
       12 . The engine of  claim 10 , wherein the second air intake port is in fluid communication with the first compressor. 
   
   
       13 . The engine of  claim 1 , wherein said second controller is configured to inject fuel into the chamber during a combustion stroke. 
   
   
       14 . The engine of  claim 2 , wherein said second controller is configured to inject fuel into the chamber during a combustion stroke. 
   
   
       15 . The engine of  claim 1 , further comprising an exhaust gas recirculation system operable to controllably provide a portion of exhaust gas from the exhaust port to an intake of the at least one compressor. 
   
   
       16 . The engine of  claim 1 , wherein the at least one compressor comprises at least two compressors providing at least two stages of compression to air upstream of the air intake port. 
   
   
       17 . The engine of  claim 16 , wherein the at least one compressor comprises at least three compressors providing at least three stages of compression to air upstream of the air intake port. 
   
   
       18 . The engine of  claim 5 , wherein the piston is driven in a reciprocating motion by a crank on a crankshaft, the engine being so constructed that the piston is at top dead center of its path when the crank is at bottom dead center on the crankshaft. 
   
   
       19 . The engine of  claim 5 , wherein the piston is driven in a reciprocating motion by the action of a crank acting directly or indirectly on a crank pin to which is attached a connecting rod to which is connected the piston, and wherein the engine is so constructed and arranged that, when the piston is around top dead center of its motion, the crank pin motion is subtracted from the straightening movement of the connecting rod. 
   
   
       20 . The engine of  claim 1 , wherein the first controller is configured to operate the intake valve to maintain the intake port open during a portion of the intake stroke and through at least a majority portion of the compression stroke of the piston. 
   
   
       21 . The engine of  claim 20 , including means for cooling the air compressed by the at least one compressor.