Patent Abstract:
A variable valve timing control device includes a drive member rotatable in synchronization with a crankshaft, a rotatable driven member connected to a camshaft arranged co-axially with the drive member, a hydraulic chamber formed at one of the drive member and the driven member, a vane dividing the hydraulic chamber into an advanced angle chamber and a retarded angle chamber, a relative rotation phase controlling mechanism which controls a relative rotation phase between the drive member and the driven member between a most retarded angle phase in which a volume of the advanced angle chamber is a maximum and a most advanced angle phase in which a volume of the retarded angle chamber is a maximum by supplying or discharging operation fluid to and/or from the advanced angle chamber and the retarded angle chamber, a lock mechanism which restricts relative rotation between the drive member and the driven member, when the relative rotation phase is a predetermined lock phase between the most advanced angle phase and the most retarded angle phase, a control mechanism performing an intermediate phase operation upon input of a signal indicating engine stop to position the relative rotation phase intermediate between the most advanced angle phase and the most retarded angle phase by operating the relative rotation phase controlling mechanism, and performing a drain operation to drain the operation fluid from both the advanced angle chamber and the retarded angle chamber after performing the intermediate phase operation.

Full Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is based on and claims under 35 U. S. C. § 119 with respect to Japanese Patent Application No. 2002-281495 filed on Sep. 26, 2002, the entire contents of which are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention is generally directed to valve timing control device. More particularly, the present invention pertains to a valve timing control device for controlling an opening and closing time of at least one of an intake valve and an exhaust valve of a internal combustion engine on the basis of the running condition of a vehicle-mounted internal combustion engine. 
     BACKGROUND OF THE INVENTION 
     In general, the variable valve timing control device comprising: a drive member rotatable in synchronization with a crankshaft, a rotatable driven member connected to a camshaft arranged co-axially with the drive member, a hydraulic chamber formed at one of the drive member and the driven member, a vane dividing the hydraulic chamber into an advanced angle chamber and a retarded angle chamber, a relative rotation phase controlling mechanism which controls a relative rotation phase between the drive member and the driven member between a most retarded angle phase in which a volume of the advanced angle chamber is a maximum and a most advanced angle phase in which a volume of the retarded angle chamber is a maximum by supplying or discharging operation fluid to and/or from the advanced angle chamber and the retarded angle chamber. 
     Further, the variable valve timing control device comprising: a lock mechanism which restricts relative rotation between the drive member and the driven member, when the relative rotation phase is a predetermined lock phase between the most advanced angle phase and the most retarded angle phase at the engine start in order to prevent the vane from oscillating in the fluid pressure chamber by periodical fluctuation torque of a cam causing by the camshaft opening and closing the valve and obtain the smooth startability of the engine and the adjusting width extending to both advanced angle direction and the retarded angle direction of the relative rotation phase of the both rotation member 
     Aforesaid lock mechanism biases a lock body provided on the rotatable drive member to the rotatable driven member side by a spring and insert the aforesaid lock body into the lock oil chamber provided on the rotatable driven member and restrain the aforesaid relative rotation and obtain lock status. On the other hand aforesaid lock mechanism draw back the lock body to the rotatable drive member side by supplying lock oil in the lock oil chamber and providing oil pressure and unlock the aforesaid lock status 
     A known valve timing control device of the general kind is disclosed in Japanese-Laid-Open 2001-50063, and it detects the relative rotation phase between the rotatable drive member and the rotatable driven member at the engine stop upon input of a signal indicating engine stop from the ignition key switch and feedback-controls the aforesaid relative rotation phase control mechanism and adjust the relative rotation phase of both rotation members to lock phase side and restrains the aforesaid relative rotation and obtain lock status by the aforesaid lock mechanism. 
     By the way, although the aforesaid control mechanism of the aforesaid valve timing control device needs to drain lock oil from the lock oil chamber and obtain the aforesaid lock status during the relatively short time from input of a signal indicating engine stop from the ignition key switch to rotation stop of the crankshaft. The aforesaid control mechanism of the aforesaid valve timing control device occasionally can not obtain the aforesaid lock status when the engine oil is yet low temperature and of high viscosity while the engine is not warm. 
     Therefore, A known valve timing control device of the general kind is disclosed in Japanese-Laid-Open 2001-355468, and it passes the relative rotation phase of both rotation member through the lock phase and obtains the lock status by the lock mechanism by making the advanced angle chamber, the retarded angle chamber and the lock oil chamber at drain status when the crankshaft is compulsorily rotated by the starter upon input of a signal indicating engine stop from the ignition key switch (hereinafter called cranking) and oscillating the aforesaid vane in the fluid pressure chamber by the fluctuation torque of the cam in order to obtain the aforesaid lock status at the engine start. 
     The causes of preventing the aforesaid lock status from being obtained are that the remaining operational oil in the advanced angle chamber or the retarded angle chamber prevents the relatively rotation, in other word, the oscillation in the fluid pressure chamber between the rotatable drive member and the rotatable driven member and that the remaining oil in the lock oil chamber prevents the lock body from inserting into the lock oil chamber. 
     Especially in case that the engine oil is low temperature as the engine not warm and the engine is restarted immediately after the engine stops, the operational oil in the advanced angle chamber or the retarded angle chamber and the lock oil in the lock oil camber occasionally can not be drained perfectly because the engine oil is yet low temperature and of high viscosity. In case that the lock oil is not drained perfectly from lock oil chamber the aforesaid lock oil prevent the relative rotation of both rotation member and the insert of the lock body and the lock status can not be obtained. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide an improved valve timing control device which overcomes the above drawbacks. 
     It is another object of the present invention to provide an improved valve timing control device which obtains exactly the lock status to restrain the relative rotation between the rotatable drive member and the rotatable driven member. 
     The invention provides a variable valve timing control device comprising: a drive member rotatable in synchronization with a crankshaft, a rotatable driven member connected to a camshaft arranged co-axially with the drive member, a hydraulic chamber formed at one of the drive member and the driven member, a vane dividing the hydraulic chamber into an advanced angle chamber and a retarded angle chamber, a relative rotation phase controlling mechanism which controls a relative rotation phase between the drive member and the driven member between a most retarded angle phase in which a volume of the advanced angle chamber is a maximum and a most advanced angle phase in which a volume of the retarded angle chamber is a maximum by supplying or discharging operation fluid to and/or from the advanced angle chamber and the retarded angle chamber, a lock mechanism which restricts relative rotation between the drive member and the driven member, when the relative rotation phase is a predetermined lock phase between the most advanced angle phase and the most retarded angle phase, a control mechanism performing an intermediate phase operation upon input of a signal indicating engine stop to position the relative rotation phase intermediate between the most advanced angle phase and the most retarded angle phase by operating the relative rotation phase controlling mechanism, and performing a drain operation to drain the operation fluid from both the advanced angle chamber and the retarded angle chamber after performing the intermediate phase operation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     FIG. 1 is an axial cross-sectional view showing structure of the valve timing control device. 
     FIG. 2 is a cross-sectional view showing the lock status of the valve timing control device by the lock mechanism. 
     FIG. 3 is a cross-sectional view showing the unlock status of the valve timing control device by the lock mechanism. 
     FIG. 4 is an operation chart showing the operation of the control valve. 
     FIG. 5 is a timing chart showing some kinds of status at the engine start. 
     FIG. 6 is a flow chart showing the control status of the valve timing control device at the engine stop. 
     FIG. 7 is a flow chart showing the maintain operation of the valve timing control device shown in FIG.  6 . 
     FIG. 8 is a flow chart showing the transfer operation of the valve timing control device shown in FIG.  6 . 
     FIG. 9 is a timing chart showing some kinds of status when the maintain operation is prosecuted at the normal stop process. 
     FIG. 10 is a timing chart showing some kinds of status when the transfer operation is prosecuted at the normal stop process. 
     FIG. 11 is a timing chart showing some kinds of status when the maintain operation and the transfer operation are not prosecuted at the normal stop process. 
     FIG. 12 is a timing chart showing some kinds of status when the maintain operation is not prosecuted at the abnormal stop process. 
     FIG. 13 is a timing chart showing some kinds of status when the maintain operation is prosecuted at the abnormal stop process. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A valve timing control device in accordance with a preferred embodiment of the present invention will be described with reference to Figures. 
     A valve timing control device referring to FIG. 1 is provided with an outer rotor  2  which is the drive-rotation member rotated simultaneusly with the crankshaft of the engine for automobile and an inner rotor  1  which is the driven-rotation member rotated simultaneusly with the camshaft  3 . 
     The inner rotor  1  is assembled integrally on the projecting end of the cam shaft  3  rotatably integrally with the camshaft  3  mounted on a cylinder head of the engine. 
     The outer rotor  2  is mounted on the outer circumference of the inner rotor  1  so as to be able to rotate within a specified range relative to the inner rotor  1  and includes a front plate  22  and a rear plate  23  and a timing sprocket  20  which is mounted integrally on the outer circumference of the outer rotor  2 . 
     The rotation transmitting member  24  which is a timing chain or a timing belt etc is installed between the timing sprocket  20  and a gear which is mounted on the crank shaft of the engine. 
     When the crank shaft begins to be rotated, the rotation torque is transmitted to the timing sprocket  20  via the rotation transmitting member  24 . The outer rotor  2  provided with the timing sprocket  20  is rotated in the rotation direction S shown in FIG.  2 . The inner rotor  1  is rotated in the rotation direction S and the camshaft  3  is rotated. The cams mounted on the camshaft  3  push down and open an intake valve or an exhaust valve. 
     The outer rotor  2  provided with several projections  4  acting as the shoe projecting in radial direction which are put side-by-side in rotational direction. A fluid pressure chamber  40  which is defined between the inner rotor  1  and the outer rotor  2  is formed between the abutting projections  4  on the outer rotor  2 . 
     A vane groove  41  are formed on the outer periferal surface of the inner rotor  1  at the position which face to each of the fluid pressure chamber  40 . A vane  5  which divides the fluid pressure chamber  40  into an advanced angle chamber  43  and a retarded angle chamber  42  in relative rotational direction(S 1 , S 2  direction shown in FIG. 2) is inserted into the vane groove  41  in a manner to be slidable in radial direction. 
     The advanced angle chamber  43  is connected to an advanced angle passage  11  formed on the inner rotor  1 . The retarded angle chamber  42  is connected to a retarded angle passage  10  formed on the inner rotor  1 . The advanced angle passage  11  and the retarded angle passage  10  are connected to an after-mentioned hydraulic pressure circuit  7 . 
     The hydraulic pressure circuit  7  functions as relative rotational phase control device which supplies and discharges engine oil as operation oil to/from one of or both the advanced angle chamber  43  or/and the retarded angle chamber  42  via the retarded angle passage  10  and the advanced angle passage  11 . The hydraulic pressure circuit  7  changes the relative position of the vane  5  in the fluid pressure chamber  40  and control the relative rotational phase of the inner rotor  1  and the outer rotor  2 (hereinafter called as the relative rotational phase of both rotors) between the most advanced angle phase(the relative rotational phase of both rotors is at which the volume of the advanced angle chamber  43  is maximum) and among the most retarded angle phase(the relative rotational phase of both rotors is at which the volume of the retarded angle chamber  42  is maximum). 
     For more detail, the hydraulic pressure circuit  7  comprises a pump  70  and a control valve  76  and an oil pan  76 . The pump  70  is driven by driving force of the engine and supply the engine oil which is operational oil or after-mentioned lock oil to the control valve  76 . The control valve  76  supplies and drains engine oil to/from several ports by changing the position of the spool with controlling a mount of the electricity of the ECU  9 . The oil pan  75  stores engine oil. The aforesaid advanced angle passage  11  and retarded angle passage  10  are connected to specified port of the aforesaid control valve  76 . 
     A lock mechanism  6  which locks the relative rotational phase of both rotors when the relative rotational phase of both rotors is the predetermined lock phase between the most advanced angle phase and the most retarded angle phase is provided between the inner rotor  1  and the outer rotor  2 . 
     The lock mechanism  6  comprises a retarded lock portion  6 A and an advanced lock portion  6 B and a lock oil chamber  62  which is formed as concave at one of the portion on the periferal surface of the inner rotor  1 . 
     The retarded lock portion  6 A and the advanced lock portion  6 B have the lock body  60  which is provided on the outer rotor  2  in a manner to be slidable in radial direction and a spring  61  which biases the lock body  60  in radial direction. The shape of the lock body  60  can be plate-shape or pin-shape or other shape. 
     The aforesaid retarded lock portion  6 A prevents the relative rotation of the inner rotor  1  from rotating to the retarded angle direction from the lock phase relative to the outer rotor  2  when the lock body  60  is inserted into the lock oil chamber  62 . The aforesaid advanced lock portion  6 B prevents the relative rotation of the inner rotor  1  from rotating to the advanced angle direction from the lock phase when the lock body  60  is inserted into the lock oil chamber  62 . So-called lock status that the relative rotational phase of both rotors can be locked at the predetermined lock phase set between the most advanced angle phase and the most retarded angle phase by inserting both lock body  60  of the retarded lock portion  6 A and advanced lock portion  6 B into the lock oil chamber  62  is obtained. The aforesaid lock phase is set at the phase where the opening and closing timing of the valve of the engine causes the smooth starting of the engine. 
     The aforesaid lock oil chamber  62  is communicated to a lock oil passage  63  formed in the inner rotor  1 . The lock oil passage  63  is connected to the specified port on the control valve  76  of the aforesaid oil pressure circuit  7 . In other word, the hydraulic pressure circuit  7  supplies and discharges engine oil as lock oil via the lock oil passage  63  to and from the lock oil chamber  62 . The lock body  60  slide back and unlock the lock condition of the relative rotational phase of both rotors as shown in FIG. 3 when the lock oil is supplied to the lock oil chamber  62  from the control valve  76 . 
     As shown in FIG. 4 the control valve  76  of the oil pressure circuit  7  changes the position of the spool from a position W 1  to a position W 4  in proportion to the mount of the electricity from the ECU  9  and supplies and drains and stops the engine oil as lock oil to and from the advanced angle chamber  43  or/and the retarded angle chamber or/and the lock oil chamber  62 . 
     In other word, when the spool position of the control valve  76  is set at the position W 1 , the drain operation to drain operation oil in both the advanced angle chamber  43  and retarded angle chamber  42  and lock oil in the lock oil chamber  62  to the oil pan  75  can be prosecuted. 
     When the spool position of the control valve  76  is set at the position W 2 , the advanced angle transfer operation to supply operation oil in the lock oil chamber  62  and unlock the lock condition of the relative rotational phase of both rotors  1 , 2  and drain operation oil from the retarded angle chamber  42  and supply operational oil to advanced angle chamber  43  and transfer the relative rotational phase of both rotors  1 , 2  into the advanced angle direction S 2  can be prosecuted. 
     When the spool position of the control valve  76  is set at the position W 3 , the hold operation to unlock the lock condition of the relative rotational phase of both rotors  1 , 2  and stop supplying operation oil to the advanced angle chamber  43  and the retarded angle chamber  42  and hold the relative rotational phase of both rotors  1 , 2  at specified phase. 
     When the spool position of the control valve  76  is set at a position W 4 , the retarded angle transfer operation to unlock the lock status of the relative rotational phase of both rotors  1 , 2  and drain operation oil from the advanced angle chamber  43  and supply operation oil to the retarded angle chamber  42  and transfer the relative rotational phase of both rotors  1 , 2  to the retarded angle direction S 1  can be prosecuted. By the way, the way of the transfer process of the control valve  76  is not defined as aforesaid way and it can be changed timely. 
     The ECU  9  provided for the engine incorporates a memory storing the specified program and CPU and input-output-interface and etc and acts as the control mechanism of the valve timing control device of this invention. 
     A detecting signal of a cam angle sensor  90   a  detecting the camshaft phase, a crank angle sensor  90   b  detecting the crankshaft phase, an oil temperature sensor  90   c  detecting the engine oil temperature, a rotation sensor  90   d  detecting the crankshaft rotation number(the engine rotation number), an ignition key switch (abbreviated to IG/SW), a vehicle speed sensor, a cooling water temperature sensor of engine, a throttle opening sensor and other sensors is inputted to the ECU  9 . The ECU  9  can obtain the relative rotational phase of both rotors  1 , 2  of the valve timing control device from the camshaft phase detected by the cam angle sensor  90   a  and the crankshaft phase detected by the crank angle sensor  90   b.    
     The ECU  9  regulates the mount of the electricity to the control valve  76  of the aforesaid oil circuit  7  ECU on the basis of the aforesaid engine oil temperature, the crankshaft rotation number, the vehicle speed, the throttle opening travel and the other engine performance parameter and controls the relative rotational phase of both rotors  1 , 2  at the phase which is suitable for the performance parameter. 
     Next, the control status of the valve timing control device at the engine start is explained on the basis of the FIG.  5 . 
     The ECU  9  as the control mechanism crank the crankshaft and start the engine after the engine start signal is inputted to the ECU  9  from the IG/SW  90   e . The ECU  9  transfers the spool of the control valve  7  to the position W 1  and drain operation oil in the advanced angle chamber  43 , the retarded angle chamber  42  and the lock oil chamber  62  when the engine starts. 
     Further, the vane  5  reciprocates in the fluid pressure chamber  40  by the periodical cam fluctuation torque caused by the camshaft opening and closing the valve when the crankshaft is cranked at the condition while the operation oil in both the advanced angle chamber  43  and the retarded angle chamber  42  is drained. The relative rotational phase of both rotors  1 , 2  fluctuates periodically among the specified phase including the aforesaid lock phase. A pair of lock bodies  60  are biased by the spring  61  to the inner rotor  1  side when the engine starts. 
     In other word, the movement that the relative rotational phase of both rotors  1 , 2  fluctuates periodically among the specified phase including the aforesaid lock phase while a pair of lock bodies  60  are biased by the spring  61  to the inner rotor  1  side makes a pair of lock bodies  60  plunge into the lock oil chamber  62  at the moment when the relative rotational phase of both rotors  1 , 2  is the lock phase and makes the relative rotational phase of both rotors  1 , 2  be hold at lock phase fairly and be locked when the temperature of the lock oil is relatively high and the pressure of the lock oil in the lock oil chamber  62  is almost zero. 
     Therefore, if the aforesaid relative rotational phase of both rotors  1 , 2  is transferred to the lock phase immediately when the engine starts the good startability of the engine can be obtained 
     Next, the control status of the valve timing control device at the engine stop is explained on the basis of the FIGS. 6 to  13 . 
     The ECU  9  as the control mechanism determines if the engine stop signal is inputted from the IG/SW  90   e  (step  100 ) as shown in FIG.  6 . When the ECU  9  determines that the engine stop signal is inputted the after-mentioned normal stop processes of step  101  to  104  are prosecuted in accordance with the engine normal stop. When the ECU  9  determines that the engine stop signal is not inputted the after-mentioned abnormal stop processes of step  105  to  108  are prosecuted in accordance with the engine abnormal stop on the basis of the happening of the engine stall etc. After the prosecution of the aforesaid normal stop processes or abnormal stop processes the ECU  9  transfers the spool of the control valve  7  to the position W 1  and prosecutes the drain operation to drain operation oil in both the advanced angle chamber  43 , the retarded angle chamber  42  and the lock oil in the lock oil chamber  62  at the step  109 . 
     Firstly the mode in which the drain operation is prosecuted at the aforesaid step  109  after the normal stop processes is explained. After the ECU  9  determines that the engine stop signal is inputted from the IG/SW  90   e  at the aforesaid step  100  the ECU  9  firstly prosecutes the step  101  and determines if the engine oil temperature detected by the oil temperature sensor  90   c  reaches to the predetermined warming-up temperature and whether the engine is at warming-up condition or not. 
     Next, when the ECU  9  determines that the engine is not at warming-up condition at the step  101  the ECU  9  prosecutes the step  102  and prosecutes the after-mentioned specified holding operation. When the ECU  9  determines that the engine is at warming-up condition at the step  101  the ECU  9  prosecutes the step  103 . 
     When the ECU  9  determines that the engine is not at warming-up condition at the aforesaid step  101  it is considered that the relative rotational phase of both rotors  1 , 2  is hold at the lock phase by the lock mechanism  6  with the spool position of the control valve  76  set to the position W 1  or that the relative rotational phase of both rotors  1 , 2  is hold near the lock phase which is at the middle phase between the aforesaid most advanced angle phase and the most retarded angle phase with the spool position of the control valve  76  set to the position W 3 . 
     Therefore, when the ECU  9  determines that the engine is not at warming-up condition at the step  101  the ECU  9  maintains the mount of the electricity to the control valve  76  of the electricity at the engine stop signal input until the rotational number of the engine becomes zero as shown in FIG.  7 . The ECU  9  prosecutes the hold operation to hold the relative rotational phase of both rotors  1 , 2  at the middle phase which is at the engine stop signal input. After the hold operation at the step  102  the ECU  9  prosecutes the drain operation of the aforesaid step  109 . 
     In other word, when the ECU  9  determines that the engine is not at warming-up condition at the step  101  the ECU  9  hold the relative rotational phase of both rotors  1 , 2  and prosecutes the drain operation at the aforesaid step  102  of the hold operation as shown in FIG. 9 until the rotation of the crankshaft stops at the hold operation of the aforesaid step  102 . If the operation oil in the advanced angle chamber  43  or the retarded angle chamber  42  or the lock oil chamber  62  is not drained because of high viscosity at low temperature and the relative rotational phase of both rotors  1 , 2  can not be oscillated with enough width the relative rotational phase of both rotors  1 , 2  is oscillated at near the middle phase and can be passed exactly through the lock phase and is secured of the lock status by the lock mechanism  6 . 
     When the ECU  9  determines that the engine is at warming-up condition at the aforesaid step  101  the ECU  9  prosecutes the step  103  and detects the relative rotational phase of both rotors  1 , 2  by the camshaft phase detected by the cam angle sensor  90   a  and the crankshaft phase detected by the crank angle sensor  90   b  and determines whether the relative rotational phase of both rotors  1 , 2  is the middle phase. 
     When the ECU  9  determines that the relative rotational phase of both rotors  1 , 2  is the most retarded angle phase or the most advanced angle phase which is not the middle phase the ECU  9  prosecutes the transfer operation at the after-mentioned step  104 . When the ECU  9  determines that the relative rotational phase of both rotors  1 , 2  is the middle phase the drain operation of the aforesaid step  109  is prosecuted. 
     The transfer operation of the aforesaid step  104  as shown in FIG. 8 for transferring the relative rotational phase of both rotors  1 , 2  to the middle phase firstly calculates the mount of the electricity for the control valve  76  and the electricity time to maintain the mount of the electricity as a control parameter of control valve  76  on the basis of the engine oil temperature detected by the oil temperature sensor  90   c , the crankshaft rotation number detected by the rotation sensor  90   d , the relative rotational phase of both rotors  1 , 2  detected by the cam angle sensor  90   a  and the crank angle sensor  90   b , the temperature of the cooling water, the shift range of the automatic transmission and the engine operation parameter at the moment when the engine stop signal is inputted. Then the control valve  76  is controlled on the basis of the aforesaid calculated control parameter. The advanced angle moving operation or the retarded angle moving operation is prosecuted to set the position of the spool of the control valve  76  at the position W 2  or the position W 4 . 
     In other word, the mount of the electricity for the control valve  76  and the electricity time to maintain the mount of the electricity to set the position of the spool of the control valve  76  at the position W 2  or the position W 4  in order to obtain the target adjusting volume of the relative rotational phase of both rotors  1 , 2  by realizing the target adjusting volume for moving the relative rotational phase of both rotors  1 , 2  to the middle phase at the engine stop is calculated at the step  104  of the transfer operation. 
     The relative rotational phase of both rotors  1 , 2  is transferred to the middle phase by turning on electricity for the control valve  76  in accordance with the calculated the mount of the electricity and the electricity time and prosecuting the advanced angle transfer operation or the retarded angle transfer operation by the control valve  76  during the specified electricity time even where the relative rotational phase of both rotors  1 , 2  is the most retarded angle phase or the most advanced angle phase at the moment when the engine stop signal is inputted. Then the aforesaid drain operation at the step  109  is prosecuted and relatively hot operation oil and lock oil is drained immediately and the aforesaid relative rotational phase of both rotors  1 , 2  oscillates at the middle phase and the operation oil in both the advanced angle chamber and the retarded angle chamber is drained and the engine stops. 
     Thus when the engine is determined to be at warming-up status at the step  101  and the relative rotational phase of both rotors  1 , 2  is determined not to be the middle phase the drain operation at the step  109  is prosecuted after the relative rotational phase of both rotors  1 , 2  is set at the middle phase as shown in FIG.  10 . Because the operation oil in the advanced angle chamber  43  or the retarded angle chamber  42  or the lock oil in the lock oil chamber  62  is relatively high temperature and of low viscosity after the drain operation at engine stop or after cranking start of the crankshaft at the engine restart the relative rotational phase of both rotors  1 , 2  can be oscillated at the middle phase excellently and can be secured to be at the lock status by the lock mechanism  6  with passing through the lock phase exactly. 
     Meanwhile when the relative rotational phase of both rotors  1 , 2  is determined to be the middle phase the ECU  9  oscillates excellently and can secure the aforesaid relative rotational phase of both rotors  1 , 2  at the lock status by the lock mechanism  6  after the drain operation at engine stop or after cranking start of the crankshaft at the engine restart by prosecuting the drain operation of the aforesaid step  109  immediately as shown in FIG. 11 because the operation oil in the advanced angle chamber  43  or the retarded angle chamber  42  or the lock oil in the lock oil chamber  62  is relatively high temperature and of low viscosity. 
     Secondly, the mode in which the drain operation of the aforesaid step  109  is explained after the prosecution of the abnormal stop operation. 
     On the abnormal stop operation after the engine stop signal is determined not to be inputted from IG/SW  90   e  at aforesaid step  100  the ECU  9  prosecutes firstly the step  105  and determines if the engine tall is avoided by the inputting avoidance signal of the engine stall. In case the engine tall can be avoided the normal operation control is prosecuted and the engine running is maintained. 
     Meanwhile in case the engine stall is determined not to be avoided the step  106  is prosecuted it is determined if the relative rotational phase of both rotors  1 , 2  is near the lock phase as same as the aforesaid step  103 . On the other hand, the step  107  is prosecuted and it is determined whether the engine at the warming-up status or not as same as the aforesaid step  101 . 
     Meanwhile in case that the relative rotational phase of both rotors  1 , 2  is determined not to be the middle phase at aforesaid step  106  or in case that the engine is at the warming-up status but the relative rotational phase of both rotors  1 , 2  is determined to be at the middle phase at aforesaid step  106  the drain operation  108  of the aforesaid step  109  immediately. 
     Thus in case that the relative rotational phase of both rotors  1 , 2  is not at the middle phase or the engine is at the warming-up status the relative rotational phase of both rotors  1 , 2  can be oscillated efficiently and the operation oil in both the advanced angle chamber  43  and the retarded angle chamber  42  is drained excellently by prosecuting immediately the drain operation when the rotation of the crankshaft immediately after the engine stall and the engine can be stopped Therefore the relative rotational phase of both rotors  1 , 2  is oscillated efficiently and the lock status is secured by the lock mechanism  6  after the drain operation at the engine stop or after the cranking start of the crankshaft at the engine restart. 
     On the other hand in case that the relative rotational phase of both rotors  1 , 2  is determined to be the middle phase at the aforesaid step  106  and the engine is not at the warming-up status at the aforesaid step  106  the mount of the electricity for the control valve  76  is maintained to the mount of the electricity of the time and the hold operation to hold the relative rotational phase of both rotors  1 , 2  at the middle phase is prosecuted and the drain operation of the aforesaid step  109  is prosecuted after the hold operation of the aforesaid step  108 . 
     In other word, when the ECU  9  determines that the engine is not at warming-up condition at the step  107  the ECU  9  hold the relative rotational phase of both rotors  1 , 2  and prosecutes the drain operation at the aforesaid step  109  of the hold operation as shown in FIG. 13 until the rotation of the crankshaft stops at the hold operation of the aforesaid step  108 . If the operation oil in the advanced angle chamber  43  or the retarded angle chamber  42  or the lock oil chamber  62  is not drained because of high viscosity at low temperature and the relative rotational phase of both rotors  1 , 2  can not be oscillated with enough width the relative rotational phase of both rotors  1 , 2  is oscillated near middle phase and can be passed exactly through the lock phase and is secured of the lock status by the lock mechanism  6 . 
     Although in this embodiment of the invention the control valve consists of single valve, it is permitted that the control valve consists of plural hydraulic control valve not only apply to the single valve. For example, it is permitted that the control valve comprises the control valve which supply/drain the operation oil to/from the retarded angle chamber  42  and the control valve which supply/drain the operation oil to/from the advanced angle chamber  43  and the control valve which supply/drain the operation oil to/from the lock oil chamber  62 . 
     Although in the aforesaid embodiment of the invention whether the engine is at the warming-up status or not is determined by determining whether the engine oil temperature reaches the predetermined temperature. It is permitted that whether the engine is at the warming-up status or not is determined by determining whether the engine cooling-water temperature reaches the predetermined temperature as other way. 
     It is permitted that the various components of the valve timing control device afore-explained can be replaced with the unitary body combined the vane  5  and the inner rotor  1  or another component of the lock mechanism  6  and etc unless the embodiment is out of the subject-matter of the invention

Technology Classification (CPC): 5