Internal combustion engine, and control apparatus and method thereof

Abstract

The amount of air to be introduced is controlled for each cylinder, whereby it is intended to make it possible to control the torque generated in each cylinder, perform an ultra-lean burn operation, purify the exhaust gas, and increase the output of an engine. An air flow control valve adapted to be on-off controlled in accordance with an operated quantity of an accelerator pedal is disposed in each branch pipe or intake port. The air flow control valve may be a throttle valve disposed in each branch pipe or it may be a variable intake valve for opening and closing the intake port.

1 . An apparatus for controlling an internal combustion engine, comprising: 
 means for determining a required amount of air for each cylinder in the engine;    a control circuit which produces a control signal in accordance with an output of said determining means;    an intake valve disposed in an intake port of each cylinder in the internal combustion engine;    an actuator which controls at least one of an opening/closing timing and stroke of said intake valve in accordance with the control signal outputted from said control circuit; and    an air flow control valve arranged in each branch passage of the internal combustion engine upstream of each intake port and is operable such that the required amount of intake air is controlled by said intake valve and said air flow control valve.    
   
   
       2 . A method for controlling an internal combustion engine, comprising controlling at least one of opening/closing timing and stroke of at least one of intake and exhaust valves in an engine in accordance with a determined amount of air required for each cylinder of the internal combustion engine, and operating an air flow control valve arranged in each branch passage of the internal combustion engine upstream of each intake port of the internal combustion engine to control intake air with the respective intake valves and air flow control valve at each cylinder of the internal combustion engine.  
   
   
       3 . An internal combustion engine provided with intake valves for controlling the opening and closing of intake ports formed in cylinders, wherein at least one of opening/closing timing and stroke of at least one of intake and exhaust valves in an engine is controllable in accordance with a determined amount of air required for each cylinder of the internal combustion engine, wherein the on-off condition of each said intake valve is defined as a function of an operated quantity of an accelerator pedal, and 
 an air flow control valve arranged in each branch passage of the internal combustion engine upstream of each intake port and is operable such that the required amount of intake air is controlled by said intake valve and said air flow control valve.    
   
   
       4 . A method for controlling an output torque of an internal combustion engine in accordance with the degree of opening of an accelerator pedal, comprising controlling at least one of opening/closing timing and stroke of at least one of intake and exhaust valves in an engine in accordance with a determined amount of air required for each cylinder of the internal combustion engine, controlling said output torque in accordance with the on-off condition of each intake valve provided in the engine, and operating an air flow control valve arranged in each branch passage of the internal combustion engine upstream of each intake port of the internal combustion engine to control intake air with the respective intake valves and air flow control valve at each cylinder of the internal combustion engine.  
   
   
       5 . The method according to  claim 5 , wherein an intake quantity detecting sensor is provided and the on-off condition of the intake valve is feedback-controlled in accordance with an output signal provided from said intake quantity detecting sensor.  
   
   
       6 . The method according to  claim 5 , wherein an internal cylinder pressure sensor for detecting an internal cylinder pressure is provided and the on-off condition of the intake valve is feedback-controlled in accordance with an output signal provided from said internal cylinder pressure sensor.  
   
   
       7 . A method according to  claim 5 , wherein a torque sensor for detecting a rotational torque of the engine is provided and the on-off condition of an intake valve is controlled in accordance with an output signal provided from said torque sensor.  
   
   
       8 . An internal combustion engine provided with intake valves for controlling opening and closing of intake ports formed in cylinders and an air flow sensor for detecting the amount of air introduced into the cylinders, wherein at least one of opening/closing timing and stroke of at least one of intake and exhaust valves in an engine is controllable in accordance with a determined amount of air required for each cylinder of the internal combustion engine, wherein the on-off condition of each said intake valve is defined as a function of both an operated quantity of an accelerator pedal and an output signal provided from said air flow sensor, and 
 an air flow control valve arranged in each branch passage of the internal combustion engine upstream of each intake port and is operable such that the required amount of intake air is controlled by said intake valve and said air flow control valve.    
   
   
       9 . An apparatus for controlling an internal combustion engine operated by introducing air from intake ports of cylinders, comprising a variable intake valve arrangement associated with each of the cylinders, and an air flow control valve is provided in each branch passage upstream of each intake port such that the required amount of air to be introduced into each of the cylinders is controllable by the respective intake valve arrangement and said air flow control valve at each cylinder.  
   
   
       10 . A method according to  claim 2 , wherein the output torque of each cylinder is controlled by controlling the required amount of air to be introduced into each cylinder.  
   
   
       11 . A variable intake valve mechanism in an internal combustion engine, comprising: 
 an intake valve for opening and closing each intake port formed in each cylinder;    a motor-driven actuator for actuating said intake valve electrically;    a control circuit which produces a control signal for said motor-driven actuator,    wherein said control circuit produces the control signal for said motor-driven actuator in accordance with an amount of air determined to be required for each cylinder so as to vary at least one of the opening/closing time and stroke of the intake valve of each cylinder, and    an air flow control valve arranged in each branch passage of the internal combustion engine upstream of each intake port and is operable such that the required amount of intake air is controlled by said intake valve and said air flow control valve.    
   
   
       12 . An apparatus for controlling the torque of an internal combustion engine, comprising: 
 branch pipes connected respectively to intake ports in cylinders to feed air to the cylinders;    a main intake pipe connected to an upstream side of said branch pipes to introduce air to the branch pipes;    a reverse flow detection type air flow sensor disposed in said main intake pipe and capable of measuring an amount of air flow through each said branch pipe, including the amount of air reverse flowing through the branch pipe;    a torque measuring means for measuring an output torque of the engine;    an air flow control valve for controlling the amount of air flowing through each said branch pipe in accordance with an amount of air determined to be required for each of the cylinders so as to control at least one of opening/closing timing and stroke of the intake valve of each cylinder; and    an air flow control valve opening compensating means for compensating the degree of opening of said air flow control valve in accordance with a variation in output of said torque measuring means to adjust the amount of air flowing through each said branch pipe.