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1. US20120111956 - Control device for a vehicle that includes a thermowax switching valve

注意: このテキストは、OCR 処理によってテキスト化されたものです。法的な用途には PDF 版をご利用ください。

[ EN ]

Claims

1. A control device for a vehicle, the vehicle including a thermowax switching valve, which includes a heating section for heating thermowax and is selectively opened and closed by melting and solidification of the thermowax, the control device comprising:
a target value setting section, which sets a target value of the temperature of the thermowax;
a wax temperature estimating section, which computes the amount of heat received by the thermowax based on the amount of heat transferred from the heating section to the thermowax and the amount of heat transferred from the thermowax to a fluid around the switching valve, and which estimates the temperature of the thermowax based on the amount of heat received and the thermal capacity of the thermowax; and
a control section for controlling the heating section such that the estimated temperature of the thermowax becomes equal to the target value,
wherein the wax temperature estimating section changes the value of the thermal capacity in accordance with variation of the estimate temperature of the thermowax across phase transition points of the thermowax.
2. The control device for a vehicle according to claim 1, wherein the target value setting section sets the target value when there is a request for opening the switching valve to a temperature less than or equal to the temperature of the thermowax at which the switching valve is fully opened.
3. The control device for a vehicle according to claim 1, wherein, in a case of opening the switching valve when there is a request to reduce the valve opening speed, the target value setting section holds the target value to the temperature of the thermowax at which the switching valve has a minute opening degree for a certain period of time and then sets the target value to the temperature of the thermowax at which the switching valve is fully opened.
4. The control device for a vehicle according to claim 1, wherein the target value setting section sets the target value when the switching valve is closed to a value at which the amount of heat received by the thermowax becomes greater than 0 and to a value that is lower than the temperature at which opening of the switching valve is started.
5. The control device for a vehicle according to claim 1, wherein the target value setting section sets the target value when the switching valve is closed to a value corresponding to a temperature of the thermowax that exists immediately before opening of the switching valve is started.
6. The control device for a vehicle according to claim 1, wherein, even if the opening degree of the switching valve is set to the same target opening degree, the target value is set to different values in a case where the opening degree of the switching valve is changed in a valve opening direction to achieve the target opening degree, and in a case where the opening degree of the switching valve is changed in a valve closing direction to achieve the target opening degree.
7. The control device for a vehicle according to claim 1, further comprising:
a detection section for detecting an opened state of the switching valve; and
a modification section, which modifies the thermal capacity in accordance with the difference between the estimate temperature of the thermowax when detecting an opened state of the switching valve and the temperature of the thermowax at which the switching valve is actually opened.
8. The control device for a vehicle according to claim 1, wherein, when the estimate temperature of the thermowax is lower than the target value, the control section heats the thermowax by the heating section, and if such is not the case, the control section stops heating.
9. The control device for a vehicle according to claim 1, wherein the thermal capacity is calculated as the thermal capacity of a combination of the switching valve and the thermowax.
10. The control device for a vehicle according to claim 1, wherein the switching valve is located in a coolant circuit that circulates an engine coolant.
11. The control device for a vehicle according to claim 10, wherein the switching valve switches between circulation and stopping of the coolant inside the engine.