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 operating 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 method comprising:
 supplying pressurized air from an intake manifold to at least one air intake port of a chamber in the cylinder;   selectively operating at least one air intake valve to open at least one air intake port to allow pressurized air to flow between the chamber and the intake manifold substantially during a majority portion of a compression stroke of the piston; and   operably controlling a fuel supply system to inject fuel into the chamber after the at least one intake valve is closed.   
   
   
       2 . The method of  claim 1 , wherein the pressurized air is cooled before being supplied to the air intake port. 
   
   
       3 . The method of  claim 2 , wherein said selectively operating includes operating a variable intake valve closing mechanism to keep at least one intake valve open. 
   
   
       4 . The method of  claim 2 , wherein the variable intake valve closing mechanism is operated electronically. 
   
   
       5 . The method of  claim 2 , wherein the selective operation of at least one air intake valve is based on at least one engine condition. 
   
   
       6 . The method of  claim 2 , wherein said selectively operating includes operating an intake valve to remain open for a portion of a second half of the compression stroke of the piston. 
   
   
       7 . The method of  claim 2 , wherein said operably controlling a fuel supply system includes operating a fuel injector assembly electronically. 
   
   
       8 . The method of  claim 1 , wherein selectively operating includes selectively operating at least one valve to open a single intake port. 
   
   
       9 . The method of  claim 1 , further comprising, at or after an intake valve is closed, selectively operating at least one intake valve to open at least one intake port through which additional pressurized air is injected into the chamber. 
   
   
       10 . The method of  claim 1 , further comprising:
 imparting rotational movement to a first turbine and a first compressor of a first turbocharger with exhaust air flowing from an exhaust port of the cylinder;   compressing air drawn from atmosphere with the first compressor;   compressing air received from the first compressor with a second compressor; and   supplying pressurized air from the second compressor to the intake manifold.   
   
   
       11 . The method of  claim 10 , wherein fuel is injected during a combustion stroke. 
   
   
       12 . The method of  claim 11 , wherein fuel injection begins during the compression stroke. 
   
   
       13 . The method of  claim 10 , wherein said selectively operating includes operating a variable intake valve closing mechanism to interrupt cyclical movement of at least one intake valve. 
   
   
       14 . The method of  claim 10 , wherein the selective operation of at least one air intake valve is based on at least one engine condition. 
   
   
       15 . The method of  claim 10 , wherein said selectively operating includes operating at least one air intake valve to remain open for a portion of a second half of the compression stroke of the piston. 
   
   
       16 . The method of  claim 10 , wherein said controllably operating a fuel supply system includes operating a fuel injector assembly electronically. 
   
   
       17 . The method of  claim 10 , wherein the air is cooled prior to supplying it to the at least one air intake port. 
   
   
       18 . The method of  claim 10 , wherein at or after a first intake valve is closed a secondary charge of pressurized air is injected into the chamber. 
   
   
       19 . The method of  claim 18 , wherein at least part of the secondary charge is injected through the first air intake port. 
   
   
       20 . The method of  claim 18 , wherein at least a part of the secondary charge is injected through a second air intake port. 
   
   
       21 . The method of  claim 18 , wherein the secondary charge is cooled prior to injection. 
   
   
       22 . The method of  claim 1 , further including pressurizing air and supplying said air to the intake manifold of the engine. 
   
   
       23 . The method of  claim 22  wherein said selectively operating includes maintaining fluid communication between the chamber and the intake manifold during a portion of an intake stroke and through at least a majority of the compression stroke. 
   
   
       24 . The method of  claim 23  further including supplying a pressurized fuel directly to the chamber during a portion of a combustion stroke. 
   
   
       25 . The method of  claim 24 , further including supplying the pressurized fuel during a portion of the compression stroke. 
   
   
       26 . The method of  claim 25 , wherein supplying the pressurized fuel includes supplying a pilot injection at a predetermined crank angle before a main injection. 
   
   
       27 . The method of  claim 26 , wherein said main injection begins during the compression stroke. 
   
   
       28 . The method of  claim 22 , wherein said pressurizing includes a first stage of pressurization and a second stage of pressurization. 
   
   
       29 . The method of  claim 28 , further including cooling air between said first stage of pressurization and said second stage of pressurization. 
   
   
       30 . The method of  claim 22 , further including cooling the pressurized air prior to supplying said air to the intake manifold. 
   
   
       31 . The method of  claim 23 , wherein said pressurizing includes a first stage of pressurization and a second stage of pressurization. 
   
   
       32 . The method of  claim 31 , further including cooling air between said first stage of pressurization and said second stage of pressurization. 
   
   
       33 . The method of  claim 22 , wherein pressurized air is supplied to the chamber in two charges. 
   
   
       34 . The method of  claim 33 , wherein a primary charge is supplied to the chamber through a port controlled by an intake valve. 
   
   
       35 . The method of  claim 34 , wherein a secondary charge is injected into the chamber during the compression stroke, at or after the intake valve is closed. 
   
   
       36 . The method of  claim 35 , wherein the secondary charge is injected through a second port. 
   
   
       37 . The method of  claim 22 , wherein said pressurizing includes pressurizing air to a ratio of at least 4:1 with respect to atmospheric pressure. 
   
   
       38 . The method of  claim 37 , further including:
 maintaining fluid communication between the chamber and the intake manifold during an intake stroke and a majority of a compression stroke; and   supplying a fuel to the chamber during at least a portion of the remaining compression stroke.   
   
   
       39 . The method of  claim 38 , wherein said majority is greater than 90 degrees crank angle after bottom dead center. 
   
   
       40 . The method of  claim 38 , wherein said supplying fuel includes injecting a first portion of fuel a predetermined period prior to injecting a second portion of fuel. 
   
   
       41 . The method of  claim 40 , wherein said injecting the second portion of fuel begins during the compression stroke and terminates during a combustion stroke. 
   
   
       42 . The method of  claim 38 , further including cooling the air prior to supplying the air to the chamber. 
   
   
       43 . The method of  claim 30 , including managing the pre-combustion conditions in the chamber of the engine. 
   
   
       44 . The method of  claim 30 , further comprising controlling each of the characteristics of:
 turbulence in the chamber;   density of the cooled, pressurized air;   pressure of the cooled, pressurized air;   temperature of the cooled, pressurized air;   mean cylinder pressure within the chamber; and   peak pressure within the chamber.   
   
   
       45 . The method of  claim 1 , wherein supplying pressurized air comprises supplying a pressurized mixture of air and recirculated exhaust gas from an intake manifold to an air intake port of a chamber in the cylinder, and wherein selectively operating comprises selectively operating an air intake valve to open the air intake port to allow the pressurized mixture of air and exhaust gas to flow between the chamber and the intake manifold substantially during a majority portion of a compression stroke of the piston. 
   
   
       46 . The method of  claim 22 , wherein said pressurizing includes subjecting air to at least one stage of compression. 
   
   
       47 . The method of  claim 46 , wherein said pressurizing includes subjecting air to two or more stages of compression. 
   
   
       48 . The method of  claim 47 , wherein said pressurizing includes subjecting air to more than two stages of compression. 
   
   
       49 . The method of  claim 30 , including providing, through motion of the piston, extra burn time for the combustion process.