Valve actuation controlling apparatus and method for engine

Abstract

After commanding an engine to stop, an electronic controller controls a variable working-angle control mechanism to increase the working angle of an intake valve in preparation for restarting of the engine. In the case of an automatic stop, which is followed by restarting of the engine in a relatively short time, the working angle of the intake valve is set to the maximum working angle of the variable working-angle control mechanism, which maximizing decompression. In a manual stop, it is necessary to allow for both hot start and cold start. Also, in the manual stop, a target working angle when the engine is stopped is set less than that of a case of the automatic stop. Thus, the starting characteristic is prevented from being degraded by increased friction of engine parts during a cold start, and knocking is prevented from occurring due to a high compression ratio in a cylinder during a hot start.

1 . A valve actuation controlling apparatus applied to an engine equipped with a variable working-angle control mechanism which varies working angle of an intake valve, 
 wherein, after commanding the engine to stop, the valve actuation controlling apparatus controls the variable working-angle control mechanism to increase the working angle of the intake valve in preparation for restarting of the engine.    
   
   
       2 . The valve actuation controlling apparatus according to  claim 1 , wherein the apparatus adjusts a throttle opening of the engine in accordance with the increase in the working angle of the intake valve after commanding the engine to stop.  
   
   
       3 . A valve actuation controlling apparatus applied to an engine equipped with a variable working-angle control mechanism which varies working angle of an intake valve, 
 wherein, after commanding the engine to stop, the valve actuation controlling apparatus controls the variable working-angle control mechanism to increase the working angle of the intake valve in preparation for restarting of the engine, and varies the increased working angle according to whether a stopping requirement of the engine is satisfied.    
   
   
       4 . The valve actuation controlling apparatus according to  claim 3 , wherein the increased working angle is varied within a range where the valve closing time of the intake valve coincides with a middle period of a compression stroke.  
   
   
       5 . The valve actuation controlling apparatus according to  claim 3 , wherein the engine includes an ignition switch and performs automatic stop/restart control, 
 wherein the engine stopping requirement comprises:    an automatic stopping requirement that is satisfied when the engine is stopped by the automatic stop/restart control; and    a manual stopping requirement that is satisfied when the ignition switch has been turned off, and the engine is stopped by the manual stopping requirement is satisfied, accordingly.    
   
   
       6 . The valve actuation controlling apparatus according to  claim 5 , wherein the increased working angle that has been varied in accordance with the automatic stopping requirement is larger than the increased working angle that has been varied in accordance with the manual stopping requirement.  
   
   
       7 . The valve actuation controlling apparatus according to  claim 6 , wherein the engine includes a cylinder, and 
 wherein the increased working angle that has been varied in accordance with the automatic stopping requirement is set to a maximum working angle of the variable working-angle control mechanism, and wherein the increased working angle that has been varied in accordance with the manual stopping requirement is equal to or lower than an upper limit of a range in which a compression ratio of air in the cylinder does not cause knocking during a hot start of the engine, and is equal to or higher than a lower limit of a range in which a compression ratio of air in the cylinder permits a torque sufficient for a cold start of the engine to be generated.    
   
   
       8 . The valve actuation controlling apparatus according to  claim 3 , wherein the engine further includes a variable phase mechanism that varies a center of the working angle of the intake valve, 
 wherein, after commanding the engine to stop, the valve actuation controlling apparatus, in preparation for restarting of the engine, sets the working angle center of the intake valve to a phase that is set according to the stopping requirement of the engine.    
   
   
       9 . The valve actuation controlling apparatus according to  claim 3 , wherein the apparatus adjusts a throttle opening of the engine in accordance with the increase in the working angle of the intake valve after commanding the engine to stop.  
   
   
       10 . An engine having a variable working-angle control mechanism which varies working angle of an intake valve and a valve actuation controlling apparatus, 
 wherein, after commanding the engine to stop, the valve actuation controlling apparatus controls the variable working-angle control mechanism to increase the working angle of the intake valve in preparation for restarting of the engine.    
   
   
       11 . The engine according to  claim 10 , wherein the valve actuation controlling apparatus adjusts a throttle opening of the engine in accordance with the increase in the working angle of the intake valve after commanding the engine to stop.  
   
   
       12 . An engine having a variable working-angle control mechanism which varies working angle of an intake valve and a valve actuation controlling apparatus, 
 wherein, after commanding the engine to stop, the valve actuation controlling apparatus controls the variable working-angle control mechanism to increase the working angle of the intake valve in preparation for restarting of the engine, and varies the increased working angle according to whether a stopping requirement of the engine is satisfied.    
   
   
       13 . The engine according to  claim 12 , wherein the increased working angle is varied within a range where the valve closing time of the intake valve coincides with a middle period of a compression stroke.  
   
   
       14 . The engine according to  claim 12 , further comprising an ignition switch, wherein the engine performs automatic stop/restart control, 
 wherein the engine stopping requirement comprises:    an automatic stopping requirement that is satisfied when the engine is stopped by the automatic stop/restart control; and    a manual stopping requirement that is satisfied when the ignition switch has been turned off, and the engine is stopped by the manual stopping requirement is satisfied, accordingly.    
   
   
       15 . The engine according to  claim 14 , wherein the increased working angle that has been varied in accordance with the automatic stopping requirement is larger than the increased working angle that has been varied in accordance with the manual stopping requirement.  
   
   
       16 . The engine apparatus according to  claim 15 , further comprising a cylinder, 
 wherein the increased working angle that has been varied in accordance with the automatic stopping requirement is set to a maximum working angle of the variable working-angle control mechanism, and wherein the increased working angle that has been varied in accordance with the manual stopping requirement is equal to or lower than an upper limit of a range in which a compression ratio of air in the cylinder does not cause knocking during a hot start of the engine, and is equal to or higher than a lower limit of a range in which a compression ratio of air in the cylinder permits a torque sufficient for a cold start of the engine to be generated.    
   
   
       17 . The engine according to  claim 12 , further comprising a variable phase mechanism that varies a center of the working angle of the intake valve, 
 wherein, after commanding the engine to stop, the valve actuation controlling apparatus, in preparation for restarting of the engine, sets the working angle center of the intake valve to a phase that is set according to the stopping requirement of the engine.    
   
   
       18 . The engine according to  claim 12 , wherein the valve actuation controlling apparatus adjusts a throttle opening of the engine in accordance with the increase in the working angle of the intake valve after commanding the engine to stop.  
   
   
       19 . A valve actuation controlling method applied to an engine equipped with a variable working-angle control mechanism which varies working angle of an intake valve, the method comprising: 
 controlling the variable working-angle control mechanism to increase the working angle of the intake valve in preparation for restarting of the engine, after commanding the engine to stop.    
   
   
       20 . The valve actuation controlling method according to  claim 19 , further comprising adjusting a throttle opening of the engine in accordance with the increase in the working angle of the intake valve after commanding the engine to stop.  
   
   
       21 . A valve actuation controlling method applied to an engine equipped with a variable working-angle control mechanism which varies working angle of an intake valve, the method comprising: 
 controlling the variable working-angle control mechanism to increase the working angle of the intake valve in preparation for restarting of the engine, after commanding the engine to stop; and    varying the increased working angle according to whether a stopping requirement of the engine is satisfied.    
   
   
       22 . The valve actuation controlling method according to  claim 21 , wherein said varying the increased working angle includes varying the increased working angle within a range where the valve closing time of the intake valve coincides with a middle period of a compression stroke.  
   
   
       23 . The valve actuation controlling method according to  claim 21 , wherein the engine includes an ignition switch and performs automatic stop/restart control, 
 wherein the engine stopping requirement comprises:    an automatic stopping requirement that is satisfied when the engine is stopped by the automatic stop/restart control; and    a manual stopping requirement that is satisfied when the ignition switch has been turned off, and the engine is stopped by the manual stopping requirement is satisfied, accordingly.    
   
   
       24 . The valve actuation controlling method according to  claim 23 , wherein the increased working angle that has been varied in accordance with the automatic stopping requirement is larger than the increased working angle that has been varied in accordance with the manual stopping requirement.  
   
   
       25 . The valve actuation controlling method according to  claim 24 , wherein the engine includes a cylinder, and 
 wherein the increased working angle that has been varied in accordance with the automatic stopping requirement is set to a maximum working angle of the variable working-angle control mechanism, and wherein the increased working angle that has been varied in accordance with the manual stopping requirement is equal to or lower than an upper limit of a range in which a compression ratio of air in the cylinder does not cause knocking during a hot start of the engine, and is equal to or higher than a lower limit of a range in which a compression ratio of air in the cylinder permits a torque sufficient for a cold start of the engine to be generated.    
   
   
       26 . The valve actuation controlling method according to  claim 21 , wherein the engine further includes a variable phase mechanism that varies a center of the working angle of the intake valve, the method comprising: 
 setting, in preparation for restarting of the engine, the working angle center of the intake valve to a phase that is set according to the stopping requirement of the engine after commanding the engine to stop.    
   
   
       27 . The valve actuation controlling method according to  claim 21 , further comprising adjusting a throttle opening of the engine in accordance with the increase in the working angle of the intake valve after commanding the engine to stop.