Method and apparatus for controlling CVVT of an engine
First Claim
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1. A method for controlling continuously controlling valve timing of a vehicle engine, comprising:
- determining if an engine has been cold-started;
if it is determined that the engine has been cold-started calculating an estimated oil temperature on the basis of a coolant temperature at starting of the engine and a period of time that has elapsed after the starting of the engine;
storing the estimated oil temperature in a memory;
controlling the continuously controlling valve timing based on the estimated oil temperature;
if it is determined that the engine has not been cold-started, detecting a current coolant temperature; and
determining if a difference between the current coolant temperature and the estimated oil temperature stored in the memory is less than a predetermined difference, wherein the controlling of the continuously controlling valve timing based on an energizing time calculated from the estimated oil temperature is executed when the difference between the current coolant temperature and the estimated oil temperature stored in the memory is less than the predetermined difference.
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Abstract
Controlling of a CVVT can be improved by controlling the CVVT based on an estimated oil temperature, the estimated oil temperature being calculated on the basis of a coolant temperature at starting of the engine and a period of time that has elapsed after the starting of the engine.
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Citations
14 Claims
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1. A method for controlling continuously controlling valve timing of a vehicle engine, comprising:
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determining if an engine has been cold-started; if it is determined that the engine has been cold-started calculating an estimated oil temperature on the basis of a coolant temperature at starting of the engine and a period of time that has elapsed after the starting of the engine; storing the estimated oil temperature in a memory; controlling the continuously controlling valve timing based on the estimated oil temperature; if it is determined that the engine has not been cold-started, detecting a current coolant temperature; and determining if a difference between the current coolant temperature and the estimated oil temperature stored in the memory is less than a predetermined difference, wherein the controlling of the continuously controlling valve timing based on an energizing time calculated from the estimated oil temperature is executed when the difference between the current coolant temperature and the estimated oil temperature stored in the memory is less than the predetermined difference. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for controlling continuously controlling valve timing of a vehicle engine, comprising:
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a coolant temperature detector for detecting coolant temperature of the engine; and an electronic control unit that is activated by predetermined software, the electronic control unit being equipped with a timer and a memory, wherein the predetermined software comprises instructions for; calculating an estimated oil temperature on the basis of a coolant temperature at starting of the engine and a period of time that has elapsed after the starting of the engine; storing the estimated oil temperature in the memory; controlling the continuously controlling valve timing based on the estimated oil temperature; determining if the engine has been cold-started, wherein the calculating of the estimated oil temperature is executed if the engine has been cold-started; detecting a current coolant temperature if the engine has not been cold-started; and determining if a difference between the current coolant temperature and the estimated oil temperature stored in the memory is less than a predetermined difference, and wherein the controlling of the continuously controlling valve timing based on the estimated oil temperature is executed when the difference between the current coolant temperature and the estimated oil temperature stored in the memory is less than the predetermined difference. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification