Variable valve timing control apparatus with supplementary oil pump

Abstract

A variable valve timing control apparatus includes: a relative rotational phase adjusting mechanism capable of adjusting a relative rotational phase between a drive-side rotational member and a driven-side rotational member between the most advanced angle phase and the most retarded angle phase; and a lock mechanism capable of locking the relative rotational phase at an intermediate phase between the most advanced angle phase and the most retarded angle phase; a first pump operated by a driving force of an engine; and an electrically driven second pump operated as an electrically driven pump. Hydraulic fluid is supplied from at least one of the first pump and the second pump, and the second pump is capable of operating even if the first pump is inoperative when the engine is not running.

1 . A variable valve timing control apparatus comprising:
 a drive-side rotational member rotatable in synchronization with a crankshaft;   a driven-side rotational member positioned coaxially with the drive-side rotational member and being rotatable integrally with a camshaft;   a fluid pressure chamber defined between the drive-side rotational member and the driven-side rotational member;   a vane dividing the fluid pressure chamber into an advanced angle chamber and a retarded angle chamber;   a relative rotational phase adjusting mechanism changing a position of the vane relative to the fluid pressure chamber by supplying hydraulic fluid to or draining hydraulic fluid from at least one of the advanced angle chamber and the retarded angle chamber the relative rotational phase adjusting mechanism adjusting a relative rotational phase between the drive-side rotational member and the driven-side rotational member between the most advanced angle phase, in which a volume of the advanced angle chamber reaches maximum, and the most retarded angle phase, in which a volume of the retarded angle chamber reaches maximum;   a lock mechanism locking the relative rotational phase at an intermediate phase between the most advanced angle phase and the most retarded angle phase;   a first pump operated by a driving force of an engine;   an electrically driven second pump   wherein the hydraulic fluid is supplied from at least one of the first pump and the second pump and the second pump is operated when the engine is stopped;   an engine start-up predicting means for predicting a start-up of the engine; and   an engine start-up controlling means for implementing an engine start-up control by operating the second pump when an engine start-up is predicted by the engine start-up predicting means.   
   
   
       2 . (canceled) 
   
   
       3 . (canceled) 
   
   
       4 . (canceled) 
   
   
       5 . (canceled) 
   
   
       6 . A variable valve timing control apparatus according to  claim 1 , wherein the engine start-up control implemented by the engine start-up controlling means is an engine start-up lock control wherein the lock mechanism is operated to lock the relative rotational phase at a first start-up phase that is suitable for an engine start-up. 
   
   
       7 . A variable valve timing control apparatus according to  claim 1 , wherein the engine start-up control implemented by the engine start-up controlling means is an engine start-up phase control which changes the relative rotational phase to a second start-up phase that is different from the first start-up phase at which the relative rotational phase is locked by the lock mechanism. 
   
   
       8 . A variable valve timing control apparatus according to  claim 7 , wherein the second start-up phase is determined based upon at least one of an engine oil temperature, a water temperature, and intake air temperature, and an outside air temperature. 
   
   
       9 . A variable valve timing control apparatus according to  claim 7 , wherein, after stopping the engine and prior to starting the engine, the lock mechanism is operated so as to implement an engine lock control whereby the relative rotational phase is locked at the first start-up phase suitable for an engine start-up. 
   
   
       10 . A variable valve timing control apparatus comprising:
 a drive-side rotational member rotatable in synchronization with a crankshaft;   a driven-side rotational member positioned coaxially with the drive-side rotational member and being rotatable integrally with a camshaft;   a fluid pressure chamber defined between the drive-side rotational member and the driven-side rotational member;   a vane dividing the fluid pressure chamber into an advanced angle chamber and a retarded angle chamber;   a relative rotational phase adjusting mechanism changing a position of the vane relative to the fluid pressure chamber by supplying hydraulic fluid to or draining hydraulic fluid from at least one of the advanced angle chamber and the retarded angle chamber, the relative rotational phase adjusting mechanism adjusting a relative rotational phase between the drive-side rotational member and the driven-side rotational member between the most advanced angle phase, in which a volume of the advanced angle chamber reaches maximum, and the most retarded angle phase, in which a volume of the retarded angle chamber reaches maximum;   a lock mechanism locking the relative rotational phase at an intermediate phase between the most advanced angle phase and the most retarded angle phase;   a first pump operated by a driving force of an engine;   an electrically driven second pump;   wherein the hydraulic fluid is supplied from at least one of the first pump and the second pump, and the second pump is capable of operating when the engine is stopped;   an engine stop predicting means for predicting an engine stop;   an engine stop controlling means for implementing an engine stop control by operating the second pump when the engine stop predicting means predicts an engine stop; and   wherein the engine stop control implemented by the engine stop controlling means is an engine stop lock control wherein a sweep operation, which adjusts the relative rotational phase to the most advanced angle phase or the most retarded angle phase, is performed, and the lock mechanism is operated to lock the relative rotational phase at the first start-up phase which is suitable for an engine start-up.   
   
   
       11 . (canceled) 
   
   
       12 . A variable valve timing control apparatus according to  claim 10 , further comprising:
 an engine stop delaying means for outputting, to an engine controlling means for controlling the engine, an engine stop delay signal for delaying the engine stop for a predetermined time when the engine stop predicting means predicts an engine stop.   
   
   
       13 . A variable valve timing control apparatus according to  claim 10 , further comprising:
 an engine stop operation predicting means for predicting a stop operation of the engine, wherein, when the engine stop operation predicting means predicts the stop operation of the engine, the engine stop controlling means allows the second pump to perform a standby operation at a predetermined output.   
   
   
       14 . A variable valve timing control apparatus according to  claim 13 , wherein the engine stop operation predicting means predicts the stop operation of the engine based upon at least one of a rotational speed of the engine and a running condition of a driven system to which a driving force of the engine is transmitted. 
   
   
       15 . A variable valve timing control apparatus according to  claim 1 , wherein the first pump and the second pump are arranged in parallel with each other. 
   
   
       16 . A variable valve timing control apparatus according to  claim 1 , wherein the second pump is arranged in series with and on the downstream side of the first pump, and wherein a oil reservoir is positioned between the first pump and the second pump. 
   
   
       17 . A variable valve timing control apparatus according to  claim 16  further comprising a bypass passage that allows hydraulic fluid to bypass the second pump. 
   
   
       18 . A variable valve timing control apparatus according to  claim 10 , wherein the first pump and the second pump are arranged in parallel with each other. 
   
   
       19 . A variable valve timing control apparatus according to  claim 10 , wherein the second pump is arranged in series with and on the downstream side of the first pump, and wherein a oil reservoir is positioned between the first pump and the second pump. 
   
   
       20 . A variable valve timing control apparatus according to  claim 19  further comprising a bypass passage that allows hydraulic fluid to bypass the second pump.