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US 6,640,168 B2Granted
Method for detecting errors in a motor vehicle engine cooling system
AssigneeRobert Bosch GmbH
InventorsFrank Kastner, Peter Wiltsch
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AssigneeRobert Bosch GmbH
InventorsFrank Kastner, Peter Wiltsch
Estimating the term…
A method for detecting errors in a motor vehicle engine cooling system is proposed according to the invention, in which an algorithm is used to not only detect an error in the cooling system, but to also determine whether the thermostat valve or the temperature sensor are defective. Differentiated error detection is achieved in that a second temperature model band is calculated for the case in which the thermostat remains in the opened state. A first temperature model band is calculated for the case in which the cooling system is in order. By comparing the course of the curve for the measured actual temperature with the two temperature model bands, a selective diagnosis can be carried out and determine whether the temperature sensor or the thermostat valve is defective. No additional hardware expenditures are required.
Method for detecting errors in the cooling system of a motor vehicle engine (1), whereby a thermostat valve (3) controls the temperature in the cooling-water circuit by opening or closing, and a temperature sensor (4) measures the actual temperature of the cooling water, and having a computer (7) that uses an algorithm to calculate a first temperature model band based on the values for the actual temperature and carries out error detection by making a comparison with the actual temperature, characterized in that the computer (7) calculates a second temperature model band for the cooling water temperature for a second temperature based on an open thermostat valve (3), that the computer (7) compares the course of the actual temperature with the second temperature model band, and that the computer (7), based on the result of the comparisons of the first and second temperature model band, determines if the temperature sensor (4) is defective or if the thermostat valve (3) is defective.
Dependencies are inferred from the claim text.