Air and fuel supply system for a combustion engine

Abstract

An internal combustion engine has an engine block defining at least one cylinder, a head, a piston, an air intake valve, and a valve actuator. The valve actuator has an actuator housing defining a tank and a bore, and a piston adapted to engages the air intake valve. The valve actuator further has a control valve disposed between the tank and the bore in the actuator housing. The control valve selectively moves between a first position where fluid is allowed to flow between the tank and the bore and a second position where the fluid is prevented from flowing to trap fluid in the bore, thereby preventing the engine valve from returning to a closed position. The internal combustion engine also has at least one turbocharger fluidly connected to the air intake port, and a fuel supply system operable to controllably inject fuel into the combustion chamber.

1 . A method of operating an internal combustion engine including at least one cylinder and a piston slidable in the cylinder, the method comprising: 
 supplying pressurized air from an intake manifold to an air intake port of a combustion chamber in the cylinder;    operating an air intake valve to open the air intake port to allow pressurized air to flow between the combustion chamber and the intake manifold substantially during a majority portion of a compression stroke of the piston; and    controlling a hydraulic actuator to close the air intake port to prohibit pressurized air from flowing between the combustion chamber and the intake manifold.    
   
   
       2 . The method of  claim 1 , wherein the controlling is based on at least one engine condition.  
   
   
       3 . The method of  claim 1 , further including controlling a fuel supply system to inject fuel into the combustion chamber.  
   
   
       4 . The method of  claim 3 , further including injecting at least a portion of the fuel during a portion of the compression stroke.  
   
   
       5 . The method of  claim 4 , wherein injecting at least a portion of the fuel includes supplying a pilot injection at a predetermined crank angle before a main injection.  
   
   
       6 . The method of  claim 5 , wherein said main injection begins during the compression stroke.  
   
   
       7 . The method of  claim 1 , further including cooling the pressurized air prior to supplying the pressurized air to the air intake port.  
   
   
       8 . The method of  claim 1 , wherein said supplying includes supplying a mixture of pressurized air and recirculated exhaust gas from the intake manifold to the air intake port, and wherein said operating of the air intake valve includes operating the air intake valve to open the air intake port to allow the pressurized air and exhaust gas mixture to flow between the combustion chamber and the intake manifold substantially during a majority portion of the compression stroke of the piston.  
   
   
       9 . The method of  claim 8 , wherein said supplying a mixture of pressurized air and recirculated exhaust gas includes providing a quantity of exhaust gas from an exhaust gas recirculation (EGR) system.  
   
   
       10 . The method of  claim 1 , further including controlling the hydraulic actuator to maintain the air intake port open to allow pressurized air to flow between the combustion chamber and the intake manifold.  
   
   
       11 . The method of  claim 1 , wherein the controlling includes moving a piston of the hydraulic actuator between a first position and a second position.  
   
   
       12 . The method of  claim 11 , further including locking the piston in the second position.  
   
   
       13 . The method of  claim 12 , wherein the piston engages the air intake valve in the second position and locking includes: 
 directing a flow of fluid from a tank disposed within the actuator housing to a bore in the actuator housing, the bore being associated with the piston; and    selectively preventing the fluid from flowing from the bore to the tank to trap fluid in the bore and prevent the piston from moving with respect to the actuator housing, the piston preventing the air intake valve from returning to the first position.    
   
   
       14 . The method of  claim 13 , further including selectively allowing the fluid to flow from the bore to the tank to release the piston and thereby allow the air intake valve to return to the second position.  
   
   
       15 . The method of  claim 14 , further including directing a portion of the flow of fluid between the tank and the bore to an accumulator.  
   
   
       16 . An internal combustion engine, comprising: 
 an engine block defining at least one cylinder;    a head connected with said engine block, the head including an air intake port, and an exhaust port;    a piston slidable in the cylinder;    a combustion chamber being defined by said head, said piston, and said cylinder;    an air intake valve controllably movable to open and close the air intake port;    an air supply system including at least one turbocharger fluidly connected to the air intake port;    a fuel supply system operable to inject fuel into the combustion chamber;    a cam assembly configured to move the air intake valve; and    a hydraulic actuator configured to selectively control movement of the air intake valve.    
   
   
       17 . The engine of  claim 16 , wherein the hydraulic actuator is configured to keep the intake valve open during at least a portion of a compression stroke of the piston.  
   
   
       18 . The engine of  claim 17 , wherein the hydraulic actuator is configured to keep the intake valve open for a portion of a second half of the compression stroke.  
   
   
       19 . The engine of  claim 16 , wherein the hydraulic actuator is configured to close the intake valve before bottom dead center of an intake stroke of the piston.  
   
   
       20 . The engine of  claim 16 , wherein the at least one turbocharger includes a first turbine coupled with a first compressor, the first turbine being in fluid communication with the exhaust port, the first compressor being in fluid communication with the air intake port; and wherein the air supply system further includes a second compressor being in fluid communication with atmosphere and the first compressor.  
   
   
       21 . The engine of  claim 16 , wherein the at least one turbocharger includes a first turbocharger and a second turbocharger, the first turbocharger including a first turbine coupled with a first compressor, the first turbine being in fluid communication with the exhaust port and an exhaust duct, the first compressor being in fluid communication with the air intake port, the second turbocharger including a second turbine coupled with a second compressor, the second turbine being in fluid communication with the exhaust duct of the first turbocharger and atmosphere, and the second compressor being in fluid communication with atmosphere and the first compressor.  
   
   
       22 . The engine of  claim 16 , further including an exhaust gas recirculation (EGR) system operable to provide a portion of exhaust gas from the exhaust port to the air supply system.  
   
   
       23 . The engine of  claim 16 , wherein hydraulic actuator includes: 
 an actuator housing including a tank;    a piston slidably disposed in the actuator housing and configured to engage the air intake valve; and    a control valve disposed between the tank and the piston, the control valve configured to selectively fluidly communicate the tank and the piston.    
   
   
       24 . The engine of  claim 23 , wherein the tank includes a spring-loaded piston.  
   
   
       25 . The engine of  claim 23 , wherein the actuator housing defines a chamber between the tank and the piston and wherein the chamber includes a spring-loaded piston.  
   
   
       26 . The engine of  claim 23 , further including a snubbing valve adapted to slow a movement of the piston.  
   
   
       27 . The engine of  claim 23 , further including a pivotable rocker arm operably coupling a cam assembly with the air intake valve, wherein the piston includes an end configured to selectively engage the rocker arm.  
   
   
       28 . A method of operating an internal combustion engine including at least one cylinder and a piston slidable in the cylinder, the method 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;    imparting rotational movement to a second turbine and a second compressor of a second turbocharger with exhaust air flowing from an exhaust duct of the first turbocharger;    compressing air drawn from atmosphere with the second compressor;    compressing air received from the second compressor with the first compressor;    supplying pressurized air from the first compressor to an air intake port of a combustion chamber in the cylinder via an intake manifold;    operating a fuel supply system to inject fuel directly into the combustion chamber;    operating a cam assembly to move the air intake valve; and    operating a hydraulic actuator to control movement of the air intake valve.    
   
   
       29 . The method of  claim 28 , wherein fuel is injected during a combustion stroke of the piston.  
   
   
       30 . The method of  claim 29 , wherein fuel injection begins during a compression stroke of the piston.  
   
   
       31 . The method of  claim 28 , wherein said operating a hydraulic actuator includes operating the hydraulic actuator to keep open the air intake valve to allow pressurized air to flow between the combustion chamber and the intake manifold during a portion of a compression stroke of the piston.  
   
   
       32 . The method of  claim 31 , wherein said operating a hydraulic actuator includes operating the hydraulic actuator to keep open the air intake valve for a portion of a second half of a compression stroke of the piston.  
   
   
       33 . The method of  claim 28 , wherein said operating a hydraulic actuator includes closing the air intake valve before bottom dead center of an intake stroke of the piston.  
   
   
       34 . The method of  claim 28 , further including operating the cam to move the air intake valve and cyclically open and close the air intake port, wherein said operating the hydraulic actuator includes interrupting the cyclical opening and closing of the air intake port.  
   
   
       35 . The method of  claim 28 , wherein operation of the hydraulic actuator is based on at least one engine condition.  
   
   
       36 . The method of  claim 28 , wherein said first and second compressors compress a mixture of air and recirculated exhaust gas, and wherein said supplying includes supplying the compressed mixture of pressurized air and recirculated exhaust gas to said intake port via said intake manifold.  
   
   
       37 . The method of  claim 28 , wherein operating a hydraulic actuator includes extending a piston to engage a rocker arm operably coupled with the air intake valve.  
   
   
       38 . The method of  claim 37 , further including allowing fluid to flow from a tank in an actuator housing to a bore in the actuator housing and trapping the fluid in the bore of the actuator housing to block retraction of the piston.  
   
   
       39 . The method of  claim 38 , further including selectively allowing fluid to drain from the bore to the tank to release the piston and thereby allow the air intake valve to close before bottom dead center of an intake stroke of the piston.  
   
   
       40 . The method of  claim 28 , further including operating the cam to move an air intake valve and cyclically open and close the air intake port, wherein said operating a hydraulic actuator includes interrupting the cyclical opening and closing of the air intake port.  
   
   
       41 . The method of  claim 28 , wherein operation of the hydraulic actuator is based on at least one engine condition.  
   
   
       42 . The method of  claim 28 , wherein said first and second compressors compress a mixture of air and recirculated exhaust gas, and wherein said supplying includes supplying the compressed mixture of pressurized air and recirculated exhaust gas to said intake port via said intake manifold.  
   
   
       43 . A method of controlling an internal combustion engine having a variable compression ratio, said engine including 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 combustion chamber, the method comprising: 
 pressurizing air;    supplying said air to an intake manifold of the engine;    maintaining fluid communication between said combustion chamber and the intake manifold during a portion of an intake stroke and through a portion of a compression stroke;    injecting fuel directly into the combustion chamber; and    controlling the communication between said combustion chamber and the intake manifold at least in part by hydraulic actuator.    
   
   
       44 . The method of  claim 43 , wherein said injecting fuel includes injecting fuel directly to the combustion chamber during a portion of a combustion stroke of the piston.  
   
   
       45 . The method of  claim 43 , wherein said injecting fuel includes injecting fuel directly to the combustion chamber during a portion of the compression stroke.  
   
   
       46 . The method of  claim 43 , wherein said injecting includes supplying a pilot injection at a predetermined crank angle before a main injection.  
   
   
       47 . The method of  claim 46 , wherein said portion of the compression stroke is at least a majority of the compression stroke.  
   
   
       48 . The method of  claim 43 , wherein said pressurizing includes a first stage of pressurization and a second stage of pressurization.  
   
   
       49 . The method of  claim 48 , further including cooling air between said first stage of pressurization and said second stage of pressurization.  
   
   
       50 . The method of  claim 43 , further including cooling the pressurized air.  
   
   
       51 . The method of  claim 43 , wherein the pressurizing includes pressurizing a mixture of air and recirculated exhaust gas, and wherein the supplying includes supplying the pressurized air and exhaust gas mixture to the intake manifold.  
   
   
       52 . The method of  claim 51 , further including cooling the pressurized air and exhaust gas mixture.  
   
   
       53 . The method of  claim 43 , further including operating the hydraulic actuator to varying a closing time of an air intake valve controlling a flow to the combustion chamber.  
   
   
       54 . The method of  claim 43 , further including operating the hydraulic actuator to move a piston of the hydraulic actuator between a first position and a second position and selectively blocking the piston in the second position with fluid from a tank disposed within the hydraulic actuator.  
   
   
       55 . The method of  claim 43 , further including controlling the communication between said combustion chamber and the intake manifold at least in part by a cam assembly.  
   
   
       56 . A method of operating an internal combustion engine including at least one cylinder and a piston slidable in the cylinder, the method comprising: 
 supplying pressurized air from an intake manifold to an air intake port of a combustion chamber in the cylinder;    operating an air intake valve to open the air intake port to allow pressurized air to flow between the combustion chamber and the intake manifold substantially during a portion of a compression stroke of the piston;    injecting fuel into the combustion chamber after the intake valve is closed, wherein the injecting includes supplying a pilot injection of fuel at a crank angle before a main injection of fuel; and    operating a hydraulic actuator to control movement of the air intake valve.    
   
   
       57 . The method of  claim 56 , wherein at least a portion of the main injection occurs during a combustion stroke of the piston.  
   
   
       58 . The method of  claim 56 , further including cooling the pressurized air prior to supplying the pressurized air to the air intake port.  
   
   
       59 . The method of  claim 56 , wherein said supplying includes supplying a mixture of pressurized air and recirculated exhaust gas from the intake manifold to the air intake port, and wherein said operating the air intake valve includes operating the air intake valve to open the air intake port to allow the pressurized air and exhaust gas mixture to flow between the combustion chamber and the intake manifold substantially during a majority portion of the compression stroke of the piston.  
   
   
       60 . The method of  claim 56 , wherein said supplying a mixture of pressurized air and recirculated exhaust gas includes controllably providing a quantity of exhaust gas from an exhaust gas recirculation (EGR) system.  
   
   
       61 . The method of  claim 56 , wherein operating a hydraulic actuator includes moving a piston of the hydraulic actuator between a first position and a second position, engaging a rocker arm operatively coupled to the air intake valve, and selectively restricting movement of the piston when in the second position.  
   
   
       62 . The method of  claim 61 , wherein the moving includes directing a fluid from a tank within the hydraulic actuator to a bore housing the piston, and selectively trapping the fluid within the bore.  
   
   
       63 . The method of  claim 62 , wherein the moving further includes allowing the fluid to drain from the bore to the tank to allow the piston to move to the first position.  
   
   
       64 . The method of  claim 61 , wherein the moving further includes moving the piston to slow a closing of the air intake valve.  
   
   
       65 . The method of  claim 56 , further including selectively mechanically linking a cam to the air intake valve to move the air intake valve between a first position at which the pressurized air flows through the air intake port and a second position at which the air intake valve blocks the flow of pressurized air through the air intake port; and 
 controlling the hydraulic actuator to decouple the mechanical link between the cam and the air intake valve.