Apparatus for and Method of Controlling a Starting Operation to Restart an Engine

Abstract

In an engine provided with a variable valve mechanism which varies an operating angle of an intake valve and a lift amount thereof, when an engine operation is automatically stopped after the establishment of an idling stop condition, the operating angle of the intake valve and the lift amount thereof are varied to be smaller, so that a load of the variable valve mechanism at an engine operation restarting time is low. Then, when the engine operation restarting is requested, a first explosion pressure is obtained by performing fuel injection and ignition on a cylinder stopped in an expansion stroke, so that the engine operation is started. Further, after a first intake stroke, the operating angle of the intake valve and the lift amount thereof are increased.

1 . An apparatus for controlling a starting operation of an engine provided with a variable valve mechanism capable of varying opening characteristics of an engine valve, comprising:
 a starting device configured to execute ignition of fuel existing in a combustion chamber of the engine in a state where an engine operation is stopped, to thereby start the engine operation; and   a load controlling device configured to forcibly reduce a load expended by the variable valve mechanism at a moment of starting of the engine operation by the starting device.   
   
   
       2 . The apparatus according to  claim 1 , wherein the load controlling device continues to hold a state where the load by the variable valve mechanism is forcibly reduced for one stroke of the engine. 
   
   
       3 . The apparatus according to  claim 1 , wherein the load controlling device continues to hold a state where the load by the variable valve mechanism is forcibly reduced up to a top dead center of compression stroke at the first time. 
   
   
       4 . The apparatus according to  claim 1 , wherein the load controlling device continues to hold a state where the load by the variable valve mechanism is forcibly reduced until judgment is made that a starting of the engine operation is completed. 
   
   
       5 . The apparatus according to  claim 1 , wherein the load controlling device forcibly controls the opening characteristics such that a load expended for driving an opening of the engine valve is small, to forcibly reduce the load by the variable valve mechanism. 
   
   
       6 . The apparatus according to  claim 5 , wherein the load controlling device forcibly controls the opening characteristics such that the load expended for driving the opening of the engine valve is small, when the engine operation is stopped. 
   
   
       7 . The apparatus according to  claim 1 , wherein the variable valve mechanism is comprised of a mechanism that is capable of varying a lift amount of the engine valve, and
 the load controlling device forcibly reduces the valve lift amount, to forcibly reduce the load by the variable valve mechanism.   
   
   
       8 . The apparatus according to  claim 1 i wherein the variable valve mechanism is comprised of a mechanism that is capable of varying an operating angle of the engine valve, and
 the load controlling device forcibly reduces the valve operating angle, to forcibly reduce the load by the variable valve mechanism.   
   
   
       9 . The apparatus according to  claim 1 , wherein
 the variable valve mechanism is comprised of a plurality of identical variable valve mechanisms arranged to be independent from each other, and   the load controlling device controls the plurality of independent variable valve mechanisms, respectively, to vary the opening characteristics of the engine valves with a time difference between the plurality of independent variable valve mechanisms, to forcibly reduce the loads by the variable valve mechanisms.   
   
   
       10 . The apparatus according to  claim 9 , wherein the engine is provided with two banks, each including the variable valve mechanism, and
 the load controlling device is configured to control the variable valve mechanism on each of the two banks to vary the opening characteristics with a time difference between the variable valve mechanisms on the two banks.   
   
   
       11 . The apparatus according to  claim 9 , wherein the load controlling device controls the plurality of independent variable valve mechanisms to vary the opening characteristics in which the loads expended for driving openings of respective of the engine valves are, respectively, small to those in which the loads expended for driving the openings of the respective engine valves are, respectively, large, with a time difference between the plurality of independent variable valve mechanisms. 
   
   
       12 . A method of controlling a starting operation of an engine provided with a variable valve mechanism capable of varying opening characteristics of an engine valve, comprising the steps of:
 judging as to whether or not there is an issuance of a request for starting the engine;   igniting fuel existing in a combustion chamber of the engine, when there is the issuance of the request for starting the engine, in a state where an engine operation is being stopped, to thereby restart the engine operation; and   forcibly reducing a load expended by the variable valve mechanism at a moment of starting of the engine operation.   
   
   
       13 . The method according to  claim 12 , wherein the step of forcibly reducing the load by the variable valve mechanism comprises the steps of:
 judging as to whether or not there has been an elapse of a period of time for one stroke of the engine from commencement of the starting of the engine operation; and   forcibly reducing the load by the variable valve mechanism during a time duration until elapsing of the said period of time has elapsed.   
   
   
       14 . The method according to  claim 12 , wherein the step of forcibly reducing the load expended by the variable valve mechanism comprises the steps of:
 judging as to whether or not there has been an elapse of a period of time from the starting of the engine operation to arriving at the compression top dead center at a first time; and   forcibly reducing the load by the variable valve mechanism during a time duration until elapsing of the said period of time.   
   
   
       15 . The method according to  claim 12 , wherein the step of forcibly reducing the load by the variable valve mechanism comprises the steps of:
 judging as to whether or not the starting of the engine operation has completed; and   forcibly reducing the load by the variable valve mechanism during a time duration until it is judged that the starting of the engine operation is completed.   
   
   
       16 . The method according to  claim 12 , wherein the step of forcibly reducing the load by the variable valve mechanism comprises the steps of:
 judging as to whether or not the engine operation is stopped; and   controlling the variable valve mechanism, when it is judged that the engine operation is stopped, toward the destination that the engine valve has the opening characteristics in which the load for driving an opening of the engine valve is small.   
   
   
       17 . The method according to  claim 12 , wherein the variable valve mechanism is comprised of a plurality of identical variable valve mechanisms, each being independent from one another, and
 the step of forcibly reducing the load by the variable valve mechanism comprises the steps of:   allowing some of the plurality of variable valve mechanisms to perform a variation of the opening characteristics of the engine valve;   judging as to whether or not there is an elapse of a given delay time from the variation of the opening characteristics of the engine;   urging, after judgment of the elapse of the delay time, the other variable valve mechanisms except for the some of the plurality of variable valve mechanisms that have not yet performed variation of the opening characteristics, to vary the opening characteristics of the engine valve.   
   
   
       18 . The method according to  claim 17 , wherein the engine is provided with first and second banks, each including the variable valve mechanism, and
 the step of allowing the some of the plurality of variable valve mechanisms to vary the opening characteristics of the engine valve, controls the variable valve mechanism on the first bank to vary the opening characteristics of the engine valve, and   the step of allowing, after the elapse of the given delay time, the other variable valve mechanisms to vary the opening characteristics, allows the variable valve mechanism on the second bank to vary the opening characteristics of the engine valve.   
   
   
       19 . The method according to  claim 17 , wherein the stop of allowing the some of the variable valve mechanisms to vary the opening characteristics of the engine valve and the step of allowing, after the elapse of the given delay time, the other variable valve mechanisms to vary the opening characteristics of the engine valve, allow the plurality of variable valve mechanisms to vary the opening characteristics such a manner that loads for driving opening of the engine valves are changed from a small load state to a large load state, respectively. 
   
   
       20 . An apparatus for controlling a starting operation of an engine provided with a variable valve mechanism capable of varying opening characteristics of an engine valve, comprising:
 operation starting means for igniting fuel existing in a combustion chamber of the engine in a state where an engine operation is stopped, to thereby start the engine operation; and   load-controlling means for forcibly reducing a load expended by the variable valve mechanism at a moment of starting the engine operation by the operation starting means.