US 6,200,021 B1 · Abnormality detector apparatus for a coolant apparatus for cooling an engine

Abstract

An abnormality detector apparatus for an engine water-cooling apparatus has an electronic control unit (ECU) for precisely and quickly determining and detecting an operation abnormality of a thermostat or a water temperature sensor. After the engine is started, the ECU calculates, over time, an engine heat generation quantity, an estimated cooling water temperature or the like on the basis of various engine operating condition parameters, such as cooling water temperature, intake temperature, engine revolution speed, amount of intake air, and the like. After the elapse of a predetermined time, the ECU compares the estimated cooling water temperature and the cooling water temperature actually detected by the water temperature sensor. If the relationship therebetween meets a predetermined condition, the ECU determines whether there is an abnormality in the operating condition of the thermostat and/or the cooling water temperature sensor.

Claims48

Dependent claims

An abnormality detector apparatus for a cooling apparatus provided in a coolant circulation passage of an engine, comprising:

a coolant temperature detector that detects a coolant temperature in the engine;
a setter that sets, after the engine is started, a coolant temperature criterion set by the setter and an abnormality condition where an abnormality appears in the coolant temperature;
and
an electronic control unit that compares the coolant temperature, detected by the coolant temperature detector, with the coolant temperature criterion, when the electronic control unit determines that an operating condition of the engine has become the abnormality condition,
wherein if the coolant temperature is lower than the coolant temperature criterion, the electronic control unit determines that the cooling apparatus has an abnormality.

2 more elements

A thermostat abnormality detector apparatus for a thermostat provided in a cooling water circulation passage of an engine, wherein the thermostat closes the cooling water circulation passage if a cooling water temperature is lower than a coolant temperature criterion and opens the cooling water circulation passage if the cooling water temperature is equal to or higher than a coolant temperature criterion, the apparatus comprising:

a cooling water temperature detector that detects the cooling water temperature in the engine;
abnormality determination means for determining that there is an abnormality in the operation of the thermostat when the cooling water temperature detected by the cooling water temperature detection means is lower than a predetermined reference water temperature after an elapse of a predetermined time following a start of the engine;
normality determination means for determining that the operation of the thermostat is normal, if the detected cooling water temperature is equal to or higher than the predetermined reference water temperature after the elapse of a predetermined time following the start of the engine;
first cooling temperature estimating means for estimating a cooling water temperature under a condition where abnormal operation of the thermostat is assumed;
second cooling temperature estimating means for estimating a cooling water temperature under a condition where a normal operation of the thermostat is assumed;
normality determination permitting means for permitting the normality determination means to operate, if the cooling water temperature estimated by the first cooling water temperature estimating means is lower than a predetermined water temperature;
abnormality determination permitting means for permitting the abnormality determination means to operate, if the cooling water temperature estimated by the second cooling water temperature estimating means is equal to or higher than the predetermined water temperature.

4 more elements

A cooling apparatus abnormality detector for a cooling apparatus having a thermostat provided in a cooling water circulation passage of an engine, and a cooling water temperature detector that detects a cooling water temperature in the engine, the abnormality detector comprising:

an abnormality detector that detects an abnormality in the cooling apparatus based on a change in the cooling water temperature after the engine is started;
and
determination means for determining which one of the thermostat and the cooling water temperature detector has an abnormality, based on a change in the cooling water temperature occurring after the abnormality is detected in the cooling apparatus.

Dependencies are inferred from the claim text.

Abnormality detector apparatus for a coolant apparatus for cooling an engine

Life of this patent

Abnormality detector apparatus for a coolant apparatus for cooling an engine

Life of this patent

Abstract

Claims48