Thermostat malfunction detecting system for engine cooling system
AssigneeDenso Corporation
InventorsKeiji Wakahara, Akira Ichikawa
Life of this patent
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Abstract
A malfunction of a thermostat in a coolant circulating path is detected from an engine side coolant temperature in consideration of the following behavior of the coolant temperature. When an open-malfunction occurs, the coolant temperature becomes different considerably from that in the normal time in the temperature range in which the thermostat is to be normally closed. When a closure-malfunction occurs, the coolant temperature becomes different considerably from that during the normal time in the temperature range in which the thermostat is to be normally opened. Alternatively, the malfunction may be detected from a difference between the engine side coolant temperature and a radiator side coolant temperature.
Claims50
A method for performing diagnosis of a cooling system of an internal combustion engine using an electronic control unit, comprising:
- detecting intake air amounts of the engine;
- detecting temperatures of the engine;
- taking a particular action associated with the diagnosis of the cooling system based at least in part on the detected intake air amounts of the engine and the detected temperatures of the engine.
A method for performing diagnosis of a cooling system of an internal combustion engine using an electronic control unit, comprising:
- detecting intake air pressures of the engine;
- detecting temperatures of the engine;
- taking a particular action associated with the diagnosis of the cooling system based at least in part on the detected intake air pressures of the engine and the detected temperatures of the engine.
A method for performing diagnosis of a cooling system of an internal combustion engine using an electronic control unit, comprising:
- detecting intake air amounts of the engine;
- detecting temperatures of the engine;
- calculating rates of increases in the detected temperatures of the engine;
- and
- taking a particular action associated with the diagnosis of the cooling system based at least in part on the detected intake air amounts of the engine and the calculated rates of temperature increases.
Dependencies are inferred from the claim text.