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 method of controlling a four stroke internal combustion engine having a variable compression ratio, said engine having a block defining a cylinder, a piston slidable in said cylinder, a head connected with said block, said piston, said cylinder, and said head defining a chamber, and said piston moving through a plurality of power cycles each involving an intake stroke, a compression stroke, an expansion stroke and an exhaust stroke, the method comprising:
 pressurizing air;   supplying said air to an intake manifold of the engine;   maintaining fluid communication between the chamber and the intake manifold substantially during a majority portion of a compression stoke of the piston; and   supplying a pressurized fuel directly to the chamber during a portion of a combustion stroke.   
   
   
       2 . The method of  claim 1 , wherein, maintaining fluid communication between the chamber and the intake manifold includes maintaining fluid communication between the chamber and the intake manifold during a portion of an intake stroke and through at least a majority portion of a compression stroke. 
   
   
       3 . The method of  claim 1 , further including supplying the pressurized fuel during a portion of the compression stroke. 
   
   
       4 . The method of  claim 3 , wherein supplying the pressurized fuel includes supplying a pilot injection at a predetermined crank angle before a main injection. 
   
   
       5 . The method of  claim 4 , wherein said main injection begins during the compression stroke. 
   
   
       6 . The method of  claim 1 , wherein said pressurizing includes a first stage of pressurization and a second stage of pressurization. 
   
   
       7 . The method of  claim 6 , further including cooling air between said first stage of pressurization and said second stage of pressurization. 
   
   
       8 . The method of  claim 1 , further including cooling the pressurized air. 
   
   
       9 . The method of  claim 1 , wherein pressurized air is supplied to the chamber in two charges.