Apparatus and method for controlling valve timing of engine

Abstract

An engine control system has an ECU and a valve timing control device (VVT). The ECU keeps the engine rotation after a driver turns off an ignition switch, and drives the VVT at least a middle position appropriate for starting the engine. Then the ECU stops fuel supply and ignition. Therefore, the VVT is surely driven to the middle position before the engine is stopped. Additionally, the system may shorten an extended running time of the engine since the engine is stopped when the valve timing reaches to the middle position. Further, the engine may be forcedly stopped if the engine is still running when a predetermined time is elapsed after the ignition switch is turned off.

What is claimed is:  
     
         1 . An apparatus for controlling valve timing of an engine for controlling a variable valve timing actuator that has a lock mechanism to lock the variable valve timing actuator in a specific position appropriate for starting the engine, comprising: 
 means for detecting an engine stopping operation;    means for driving the variable valve timing actuator to the specific position or a position advanced more than the specific position after the engine stopping operation is detected; and    means for stopping the engine when the variable valve timing actuator reaches to the specific position or the position advanced more than the specific position.    
     
     
         2 . The apparatus for controlling valve timing of the engine according to  claim 1 , wherein the engine has a fuel injector and an ignition device, and wherein the stopping means stops at least a fuel injection from the fuel injector.  
     
     
         3 . The apparatus for controlling valve timing of the engine according to  claim 1  further comprising means for stopping the engine when a predetermined time is elapsed from the detection of the engine stopping operation, the predetermined time being set to be capable of preventing an operator who gives the engine stopping operation from an uncomfortable feeling.  
     
     
         4 . The apparatus for controlling valve timing of the engine according to  claim 1 , wherein the variable valve timing actuator is hydraulically driven by oil supplied by the engine and is controlled by a hydraulic control device.  
     
     
         5 . The apparatus for controlling valve timing of the engine according to  claim 1 , wherein the engine stopping means stops the engine when the lock mechanism locks the variable valve timing actuator.  
     
     
         6 . The apparatus for controlling valve timing of the engine according to  claim 2 , wherein the detecting means includes an ignition switch, and wherein the apparatus further comprises means for providing an electrical connection between the ignition switch and the fuel injector.  
     
     
         7 . The apparatus for controlling valve timing of the engine according to  claim 6 , further comprising means for providing an electrical connection between the ignition switch and the ignition device.  
     
     
         8 . The apparatus for controlling valve timing of the engine according to  claim 1 , further comprising means for urging the lock mechanism toward a lock position when the variable valve timing actuator is driven toward the specific position.  
     
     
         9 . The apparatus for controlling valve timing of the engine according to  claim 1 , wherein the variable valve timing actuator has a restricting mechanism for restricting the variable valve timing actuator within a range from the specific position to an advanced position, the advanced position being defined on an advanced side of the specific position and on a retarded side of a most advanced position.  
     
     
         10 . The apparatus for controlling valve timing of the engine according to  claim 1 , wherein the variable valve timing actuator has a rotor and a housing relatively rotatable each other, and wherein the lock mechanism has a lock pin urged to a lock position by a spring, a lock hole arranged to engage with the lock pin when the variable valve timing actuator is in the specific position, and a groove arranged to engage with the lock pin to restrict a relative rotation of the rotor within a range from the specific position to the position advanced more than the specific position.  
     
     
         11 . An apparatus for controlling valve timing of an engine for controlling a variable valve timing actuator that has a lock mechanism to lock the variable valve timing actuator in a specific position appropriate for starting the engine, comprising: 
 means for detecting an engine stopping operation;    means for keeping the engine running after the engine stopping operation is detected until a predetermined time is elapsed from the detection of the engine stopping operation;    means for advancing the variable valve timing actuator toward the specific position after the engine stopping operation is detected; and    means for stopping the engine when the variable valve timing actuator is advanced to at least the specific position.    
     
     
         12 . The apparatus for controlling valve timing of the engine according to  claim 11 , further comprising means for urging the lock mechanism toward a lock position after the engine stopping operation is detected until the engine is started again.  
     
     
         13 . The apparatus for controlling valve timing of the engine according to  claim 11 , further comprising means for urging the lock mechanism toward a lock position when the engine is driven by a starter motor.  
     
     
         14 . A method for controlling valve timing of an engine having a variable valve timing actuator that has a lock mechanism to lock the variable valve timing actuator in a specific position appropriate for starting the engine, comprising the steps of: 
 detecting an engine stopping operation;    driving the variable valve timing actuator to the specific position or a position advanced more than the specific position after the engine stopping operation is detected; and    stopping the engine when the variable valve timing actuator reaches to the specific position or the position advanced more than the specific position.    
     
     
         15 . The method for controlling valve timing of the engine according to  claim 14 , wherein the engine is stopped by stopping at least a fuel injection from a fuel injector.  
     
     
         16 . The method for controlling valve timing of the engine according to  claim 14 , further comprising a step of stopping the engine when a predetermined time is elapsed from the detection of the engine stopping operation, the predetermined time being set to be capable of preventing an operator who gives the engine stopping operation from an uncomfortable feeling.  
     
     
         17 . The method for controlling valve timing of the engine according to  claim 14 , wherein the variable valve timing actuator is hydraulically driven by oil supplied by the engine and is controlled by a hydraulic control device.  
     
     
         18 . The method for controlling valve timing of the engine according to  claim 14 , wherein the engine is stopped when the lock mechanism locks the variable valve timing actuator.  
     
     
         19 . The method for controlling valve timing of the engine according to  claim 15 , further comprising a step of disconnecting an electrical connection between a battery and a fuel injector.  
     
     
         20 . The method for controlling valve timing of the engine according to  claim 19 , further comprising a step of disconnecting an electrical connection between a battery and an ignition device.