Apparatus and method of determining failure in thermostat
First Claim
1. An apparatus of determining a failure in a thermostat for controlling the flow of a coolant into a radiator in response to an actual water temperature of the coolant for an engine in a vehicle, the apparatus comprising:
- a water temperature detector that detects the actual water temperature; and
a controller including;
a water temperature estimator that calculates an estimated water temperature of the coolant; and
a failure determining unit that compares the actual water temperature detected by the water temperature detector with the estimated water temperature calculated by the water temperature estimator under cold start of the engine and determines whether the thermostat is valve-open failure,wherein in an automatic stop state of the engine, the water temperature estimator applies a behavior of the actual water temperature to an estimated water temperature calculated immediately before automatic stop of the engine to calculate, based on a temperature gradient of the actual water temperature such that a temperature gradient of an estimated water temperature in the automatic stop state of the engine varies identical to the temperature gradient of the actual water temperature, the estimated water temperature in the automatic stop state of the engine.
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Accused Products
Abstract
An apparatus for determining a failure in a thermostat for controlling the flow of a coolant into a radiator in response to an actual water temperature of the coolant for an engine in a vehicle includes: a water temperature detector that detects the actual water temperature; a water temperature estimator that calculates an estimated water temperature of the coolant; and a failure determining unit that compares the actual water temperature detected by the water temperature detector with the estimated water temperature calculated by the water temperature estimator under cold start of the engine and determines whether the thermostat is valve-open failure. In an engine nonoperating mode including at least automatic stop of the engine, the water temperature estimator applies a behavior of the actual water temperature to an estimated water temperature calculated immediately before automatic stop of the engine to calculate an estimated water temperature in the engine nonoperating mode.
11 Citations
10 Claims
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1. An apparatus of determining a failure in a thermostat for controlling the flow of a coolant into a radiator in response to an actual water temperature of the coolant for an engine in a vehicle, the apparatus comprising:
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a water temperature detector that detects the actual water temperature; and a controller including; a water temperature estimator that calculates an estimated water temperature of the coolant; and a failure determining unit that compares the actual water temperature detected by the water temperature detector with the estimated water temperature calculated by the water temperature estimator under cold start of the engine and determines whether the thermostat is valve-open failure, wherein in an automatic stop state of the engine, the water temperature estimator applies a behavior of the actual water temperature to an estimated water temperature calculated immediately before automatic stop of the engine to calculate, based on a temperature gradient of the actual water temperature such that a temperature gradient of an estimated water temperature in the automatic stop state of the engine varies identical to the temperature gradient of the actual water temperature, the estimated water temperature in the automatic stop state of the engine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of determining a failure in a thermostat for controlling the flow of a coolant into a radiator in response to an actual water temperature of the coolant for an engine in a vehicle, the method comprising:
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determining whether the engine is cold-started; detecting the actual water temperature, if the engine is cold-started, and applying a behavior of the actual water temperature to an estimated water temperature calculated immediately before automatic stop of the engine in an engine automatic stop state of the engine to calculate, based on a temperature gradient of the actual water temperature such that a temperature gradient of an estimated water temperature varies in the automatic stop state of the engine varies identical to the temperature gradient of the actual water temperature, the estimated water temperature in the automatic stop state of the engine; and comparing the actual water temperature with the estimated water temperature to determine whether the thermostat is valve-open failure.
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Specification