Apparatus for controlling valve timing of engine
First Claim
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1. An apparatus for controlling a valve timing of an engine, comprising:
- a variable valve timing actuator having a hydraulic actuator which rotates a camshaft in an advance or retard direction relative to a crankshaft;
means for advancing the valve timing to at least a middle position when the engine is stopped; and
means for preparing the advancing control of the advancing means before the engine is stopped, the means controlling the engine into a condition that helps to advance the valve timing by the advancing means;
wherein the advancing means has at least one of an assist spring which assist to rotate the camshaft in the advance direction, and means for controlling the hydraulic actuator to rotate the camshaft in the advance direction when the engine is stopped;
the preparing means comprises at least one of means for increasing an engine speed when the engine is in an idling and a temperature of an oil supplied to the hydraulic actuator is high, pre-advancing means for advancing the valve timing previously when the engine is in an idling and a temperature of an oil supplied to the hydraulic actuator is high, and means for decreasing a temperature of an oil supplied to the hydraulic actuator when the temperature of oil is high.
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Abstract
A valve timing control apparatus has a variable valve timing actuator. The system advances the valve timing to at least a middle position before the engine is completely stopped. The middle position is appropriate to start the engine. Before stopping the engine, if the oil temperature is too high to maintain a viscosity, the system provides a control to assist the above-described advancing control. For instance, the system increases the engine speed to supply a sufficient amount and pressure of oil. The system slightly advances the valve timing while the engine is in an idling.
42 Citations
27 Claims
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1. An apparatus for controlling a valve timing of an engine, comprising:
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a variable valve timing actuator having a hydraulic actuator which rotates a camshaft in an advance or retard direction relative to a crankshaft;
means for advancing the valve timing to at least a middle position when the engine is stopped; and
means for preparing the advancing control of the advancing means before the engine is stopped, the means controlling the engine into a condition that helps to advance the valve timing by the advancing means;
wherein the advancing means has at least one of an assist spring which assist to rotate the camshaft in the advance direction, and means for controlling the hydraulic actuator to rotate the camshaft in the advance direction when the engine is stopped;
the preparing means comprises at least one of means for increasing an engine speed when the engine is in an idling and a temperature of an oil supplied to the hydraulic actuator is high, pre-advancing means for advancing the valve timing previously when the engine is in an idling and a temperature of an oil supplied to the hydraulic actuator is high, and means for decreasing a temperature of an oil supplied to the hydraulic actuator when the temperature of oil is high. - View Dependent Claims (2, 3)
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4. An apparatus for controlling a valve timing of an engine, comprising;
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a variable valve timing actuator having a hydraulic actuator which rotates a camshaft in an advance or retard directions relative to a crankshaft;
means for advancing the valve timing to at least a middle position when the engine is stopped; and
means for increasing an engine speed when the engine is in an idling and a temperature of an oil supplied to the hydraulic actuator is high. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11)
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12. An apparatus for controlling a valve timing of an engine, comprising;
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a variable valve timing actuator having a hydraulic actuator which rotates a camshaft in an advance or retard directions relative to a crankshaft;
means for advancing the valve timing to at least a middle position when the engine is stopped; and
means for decreasing a temperature of an oil supplied to the hydraulic actuator when the temperature of oil is high. - View Dependent Claims (13)
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14. An apparatus for controlling a valve timing of an engine, comprising:
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a variable valve timing actuator having a hydraulic actuator which rotates a camshaft in an advance or retard direction relative to a crankshaft;
means for advancing the valve timing to at least a middle position when the engine is stopped; and
means for preparing the advancing control of the advancing means before the engine is stopped, the means controlling the engine into a condition that helps to advance the valve timing by the advancing means;
wherein the preparing means comprises at least one of means for increasing an engine speed when the engine is idling and a temperature of an oil supplied to the hydraulic actuator is high, pre-advancing means for advancing the valve timing previously when the engine is idling and a temperature of an oil supplied to the hydraulic actuator is high, and means for decreasing a temperature of an oil supplied to the hydraulic actuator when the temperature of oil is high. - View Dependent Claims (15)
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16. A method of controlling a valve timing of an engine, the method comprising:
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providing a variable valve timing actuator having a hydraulic actuator which rotates a camshaft in an advance or retard direction relative to a crankshaft;
advancing the valve timing to at least a middle position when the engine is stopped; and
increasing an engine speed when the engine is idling and a temperature of an oil supplied to the hydraulic actuator is high. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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24. A method of controlling a valve timing of an engine, the method comprising:
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providing a variable valve timing actuator having a hydraulic actuator which rotates a camshaft in an advance or retard direction relative to a crankshaft;
advancing the valve timing to at least a middle position when the engine is stopped; and
decreasing a temperature of an oil supplied to the hydraulic actuator when the temperature of oil is high. - View Dependent Claims (25)
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26. A method of controlling a valve timing of an engine, the method comprising:
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providing a variable valve timing actuator having a hydraulic actuator which rotates a camshaft in an advance or retard direction relative to a crankshaft;
advancing the valve timing to at least a middle position when the engine is stopped; and
preparing control of advancing the valve timing before the engine is stopped, the engine being controlled into a condition that helps to advance the valve timing;
wherein preparing control of advancing comprises at least one of increasing an engine speed when the engine is idling and a temperature of an oil supplied to the hydraulic actuator is high, advancing the valve timing previously when the engine is idling and a temperature of an oil supplied to the hydraulic actuator is high, and decreasing a temperature of an oil supplied to the hydraulic actuator when the temperature of oil is high. - View Dependent Claims (27)
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Specification