Engine valve timing controller

An engine valve timing controller for controlling a hydraulically driven variable valve timing mechanism, comprising:

• a coolant temperature detecting device arranged and configured to detect engine coolant temperature;
• an intake air temperature detecting device arranged and configured to detect engine intake air temperature;
• and
• a control unit operatively coupled to said coolant temperature detecting device and operatively coupled to said intake air temperature detecting device to receive signals that are representative of the engine coolant temperature and the engine intake air temperature, said control unit being configured to control the variable valve timing mechanism by
• determining if the difference between the engine coolant temperature and the engine air intake temperature at time of engine startup is less than or equal to a prescribed temperature value, and then preventing operation of the variable valve timing mechanism until the engine coolant temperature at least reaches a first operation permission coolant temperature that is higher than the operation assurance oil temperature of the variable valve timing mechanism;
• and
• determining if an absolute difference between the engine coolant temperature and the engine air intake temperature at time of engine startup exceeds said prescribed temperature value, and then preventing operation of the variable valve timing mechanism until the engine coolant temperature at least reaches a second operation permission coolant temperature that is higher than said first operation permission coolant temperature.

An engine valve timing controller for controlling a hydraulically driven variable valve timing mechanism, comprising:

• a coolant temperature detecting device arranged and configured to detect engine coolant temperature;
• an intake air temperature detecting device arranged and configured to detect engine intake air temperature;
• and
• a control unit operatively coupled to said coolant temperature detecting device and operatively coupled to said intake air temperature detecting device to receive signals that are representative of the engine coolant temperature and the engine intake air temperature, said control unit including
• a permission condition/temperature setting device arranged and configured to set a threshold value for the coolant temperature at which operation of the variable valve timing mechanism will be permitted based on a comparison of the engine coolant temperature and the engine intake air temperature at time of engine startup with the operation assurance oil temperature of the variable valve timing mechanism;
• and
• an operation permitting device arranged and configured to permit operation of the variable valve timing mechanism when the coolant temperature reaches or exceeds the threshold value set by said permission condition/temperature setting device.

An engine valve timing controller for controlling a hydraulically driven variable valve timing mechanism, comprising:

• coolant temperature detecting means for detecting engine coolant temperature;
• intake air temperature detecting means for detecting engine intake air temperature;
• control means for controlling operation of the variable valve timing mechanism based on temperature signals from said coolant temperature detecting means and said intake air temperature detecting means,
• said control means preventing operation of the variable valve timing mechanism until the engine coolant temperature at least reaches a first operation permission coolant temperature that is higher than an operation assurance oil temperature of the variable valve timing mechanism when both the engine coolant temperature and the engine air intake temperature at time of engine startup are greater than or equal to the operation assurance oil temperature,
• said control means preventing operation of the variable valve timing mechanism until the engine coolant temperature at least reaches a second operation permission coolant temperature that is higher than said first operation permission coolant temperature when at least one of the engine coolant temperature and the engine intake temperature at time of engine startup is less than the operation assurance oil temperature.