Abnormality determination apparatus and abnormality determination method for coolant temperature sensor, and engine cooling system
First Claim
1. A coolant temperature sensor abnormality determination apparatus for use with an engine cooling system having:
- (i) a coolant passageway including an engine coolant passageway and a bypass passageway that bypasses an engine, (ii) a control valve configured to be in an open state to allow mixing of coolant from the engine coolant passageway and coolant from the bypass passageway at a confluence between the engine coolant passageway and the bypass passageway and configured to be in a closed state to restrict the mixing of the coolant from the engine coolant passageway and the coolant from the bypass passageway at the confluence between the engine coolant passageway and the bypass passageway, (iii) an engine coolant temperature sensor configured to detect an engine coolant temperature in the engine coolant passageway, and (iv) a bypass coolant temperature sensor arranged in the coolant passageway, downstream of the confluence between the engine coolant passageway and the bypass passageway, the coolant temperature sensor abnormality determination apparatus comprising;
an electronic control unit configured to;
open the control valve when a difference between an atmospheric temperature around the engine and the engine coolant temperature detected by the engine coolant temperature sensor at the time of starting the engine is greater than a threshold value; and
determine only after the control valve is opened that the engine coolant temperature sensor is abnormal, if the difference between;
(i) a temperature detected by the engine coolant temperature sensor, and (ii) a temperature detected by the bypass coolant temperature sensor, is greater than a predetermined value.
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Accused Products
Abstract
When a temperature difference between intake air temperature that detected by an intake air temperature sensor and engine coolant temperature thw1 detected by an engine coolant temperature sensor is greater than a threshold value, a coolant temperature sensor abnormality determination apparatus opens a changeover valve to cause the coolant to flow into an engine coolant passageway, thereby mixing the coolant in an engine and the coolant in a heater passageway (bypass passageway). If the temperature difference between the engine coolant temperature thw1 and a heater inlet coolant temperature (bypass coolant temperature) thw2 occurring after the changeover valve opens is less than or equal to a predetermined value, the apparatus determines that the engine coolant temperature sensor is normal. If the temperature difference is greater than the predetermined value, the apparatus determines that the engine coolant temperature sensor is abnormal.
19 Citations
13 Claims
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1. A coolant temperature sensor abnormality determination apparatus for use with an engine cooling system having:
- (i) a coolant passageway including an engine coolant passageway and a bypass passageway that bypasses an engine, (ii) a control valve configured to be in an open state to allow mixing of coolant from the engine coolant passageway and coolant from the bypass passageway at a confluence between the engine coolant passageway and the bypass passageway and configured to be in a closed state to restrict the mixing of the coolant from the engine coolant passageway and the coolant from the bypass passageway at the confluence between the engine coolant passageway and the bypass passageway, (iii) an engine coolant temperature sensor configured to detect an engine coolant temperature in the engine coolant passageway, and (iv) a bypass coolant temperature sensor arranged in the coolant passageway, downstream of the confluence between the engine coolant passageway and the bypass passageway, the coolant temperature sensor abnormality determination apparatus comprising;
an electronic control unit configured to; open the control valve when a difference between an atmospheric temperature around the engine and the engine coolant temperature detected by the engine coolant temperature sensor at the time of starting the engine is greater than a threshold value; and determine only after the control valve is opened that the engine coolant temperature sensor is abnormal, if the difference between;
(i) a temperature detected by the engine coolant temperature sensor, and (ii) a temperature detected by the bypass coolant temperature sensor, is greater than a predetermined value. - View Dependent Claims (2, 3, 4, 8, 9)
- (i) a coolant passageway including an engine coolant passageway and a bypass passageway that bypasses an engine, (ii) a control valve configured to be in an open state to allow mixing of coolant from the engine coolant passageway and coolant from the bypass passageway at a confluence between the engine coolant passageway and the bypass passageway and configured to be in a closed state to restrict the mixing of the coolant from the engine coolant passageway and the coolant from the bypass passageway at the confluence between the engine coolant passageway and the bypass passageway, (iii) an engine coolant temperature sensor configured to detect an engine coolant temperature in the engine coolant passageway, and (iv) a bypass coolant temperature sensor arranged in the coolant passageway, downstream of the confluence between the engine coolant passageway and the bypass passageway, the coolant temperature sensor abnormality determination apparatus comprising;
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5. A coolant temperature sensor abnormality determination method for use in an engine cooling system having:
- (i) a coolant passageway including an engine coolant passageway and a bypass passageway that bypasses an engine, (ii) a control valve configured to be in an open state to allow mixing of coolant from the engine coolant passageway and coolant from the bypass passageway at a confluence between the engine coolant passageway and the bypass passageway and configured to be in a closed state to restrict the mixing of the coolant from the engine coolant passageway and the coolant from the bypass passageway at the confluence between the engine coolant passageway and the bypass passageway, (iii) an engine coolant temperature sensor configured to detect an engine coolant temperature in the engine coolant passageway, and (iv) a bypass coolant temperature sensor arranged in the coolant passageway, downstream of the confluence between the engine coolant passageway and the bypass passageway, the coolant temperature sensor abnormality determination method comprising;
opening the control valve when a difference between an atmospheric temperature around the engine and the engine coolant temperature detected by the engine coolant temperature sensor at the time of starting the engine is greater than a threshold value; and determining only after the control valve is opened that the engine coolant temperature sensor is abnormal, if the difference between;
(i) a temperatures detected by the engine coolant temperature sensor, and (ii) a temperature detected by the bypass coolant temperature sensor, is greater than a predetermined value. - View Dependent Claims (6, 10, 11)
- (i) a coolant passageway including an engine coolant passageway and a bypass passageway that bypasses an engine, (ii) a control valve configured to be in an open state to allow mixing of coolant from the engine coolant passageway and coolant from the bypass passageway at a confluence between the engine coolant passageway and the bypass passageway and configured to be in a closed state to restrict the mixing of the coolant from the engine coolant passageway and the coolant from the bypass passageway at the confluence between the engine coolant passageway and the bypass passageway, (iii) an engine coolant temperature sensor configured to detect an engine coolant temperature in the engine coolant passageway, and (iv) a bypass coolant temperature sensor arranged in the coolant passageway, downstream of the confluence between the engine coolant passageway and the bypass passageway, the coolant temperature sensor abnormality determination method comprising;
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7. An engine cooling system comprising:
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a coolant passageway having an engine coolant passageway and a bypass passageway that bypasses an engine; a control valve configured to be in an open state to allow mixing of coolant from the engine coolant passageway and coolant from the bypass passageway at a confluence between the engine coolant passageway and the bypass passageway and configured to be in a closed state to restrict the mixing of the coolant from the engine coolant passageway and the coolant from the bypass passageway at the confluence between the engine coolant passageway and the bypass passageway; an engine coolant temperature sensor configured to detect an engine coolant temperature in the engine coolant passageway; a bypass coolant temperature sensor that is arranged in the coolant passageway, downstream of the confluence between the engine coolant passageway and the bypass passageway; and an electronic control unit configured to; open the control valve when a difference between an atmospheric temperature around the engine and the engine coolant temperature detected by the engine coolant temperature sensor at the time of starting the engine is greater than a threshold value; and determine only after the control valve is opened that the engine coolant temperature sensor is abnormal, if the difference between;
(i) a temperature detected by the engine coolant temperature sensor, and (ii) a temperature detected by the bypass coolant temperature sensor, is greater than a predetermined value. - View Dependent Claims (12, 13)
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Specification