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US 6,763,709 B1Granted
Vehicle
AssigneesBayerische Motoren Werke Aktiengesellschaft, Land Rover
InventorsMartin Roy Haggett, William Richard Hutchins, Michael Krauss
Life of this patent
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AssigneesBayerische Motoren Werke Aktiengesellschaft, Land Rover
InventorsMartin Roy Haggett, William Richard Hutchins, Michael Krauss
Estimating the term…
A vehicle (10) is disclosed which includes a thermostat (22) in a bottom hose (24) of a radiator (16). An onboard diagnostic arrangement is provided to monitor the efficiency of the thermostat (22). Temperature sensors (S1, S2) are provided to monitor the temperature of the coolant across the radiator (16) so that a controller (40) can derive from those measurements the temperature differential across the thermostat (22). If the temperature Teng of the coolant at the thermostat inlet is below the thermostat opening temperature Topen and the differential temperature between the thermostat inlet temperature Teng and the thermostat outlet temperature Trad is below a fault threshold Dtstat, the thermostat (22) is evaluated as being stuck open or leaking, which results in a fault being recorded and a malfunction indicator lamp (MIL) being illuminated.
A vehicle comprising a cooling circuit including a thermostat arranged in use to control the flow of a coolant around at least a part of the cooling circuit, the vehicle further comprising a control means arranged in use to carry out an on-board fault detection test routine to establish the operational condition of the thermostat, the test routine being arranged to determine the condition of the thermostat from a comparison between a thermostat inlet temperature and a thermostat outlet temperature and to determine that the thermostat is faulty if the thermostat inlet temperature is below an opening temperature of the thermostat and there is a temperature differential between the thermostat inlet temperature and the thermostat outlet temperature which differential is below a predetermined fault threshold, the cooling circuit further comprising a radiator and the thermostat being arranged in use to control the flow of the coolant through the radiator, characterised in that the thermostat inlet temperature is derived from a top hose or radiator inlet temperature and/or the thermostat outlet temperature is derived from a bottom hose or radiator outlet temperature.
A method of establishing the operational condition of a thermostat included in a cooling circuit of a vehicle by performing an on-board fault detection test routine which includes comparing a thermostat inlet temperature and a thermostat outlet temperature and determining that the thermostat is faulty if the thermostat inlet temperature is below an opening temperature of the thermostat and there is a temperature differential between the thermostat inlet temperature and the thermostat outlet temperature which differential is below a predetermined fault threshold, characterised in that the method includes deriving the thermostat inlet temperature from a top-hose or radiator inlet temperature and/or deriving the thermostat outlet temperature from a bottom hose or radiator outlet temperature.
Dependencies are inferred from the claim text.