Measuring and testing – Simulating operating condition – Marine
Reexamination Certificate
1999-06-18
2001-06-05
McCall, Eric S. (Department: 2855)
Measuring and testing
Simulating operating condition
Marine
C123S041010, C340S449000
Reexamination Certificate
active
06240774
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a system for detecting or discriminating malfunction of an internal combustion engine radiator, more particularly to a system for detecting or discriminating malfunction of a thermostat in a cooling system of an internal combustion engine.
2. Description of the Related Art
The internal combustion engine of a vehicle is connected through a communicating passage with a radiator for cooling a coolant. A thermostat (a shut-off valve) is installed in the communicating passage. The thermostat closes the communicating passage when the coolant temperature is low, such as at engine starting, and opens it when the temperature rises so as to pass coolant into the radiator for cooling.
The radiator is one of the on-board components of a vehicle. The ability to detect or discriminate radiator malfunction is therefore desirable. For example, Japanese Laid-open Patent Application No. Hei 6(1994)-213117, which relates to a radiator equipped with a thermally insulated tank for storing coolant heated during ordinary operation, teaches a system that detects the coolant temperature at engine starting and determines that the thermally insulated tank is out of order when the detected temperature is abnormally low.
This earlier system can also determine when the thermostat is stuck closed or stuck open based on abnormally high or low detected coolant temperature during normal engine operation.
However, the ability of this conventional system to detect thermostat malfunction is limited to times when the detected coolant temperature is abnormal. It therefore does not provide satisfactory detection accuracy and response.
SUMMARY OF THE INVENTION
The object of this invention is therefore to overcome this drawback of the prior art and for this to provide a system for detecting or discriminating malfunction of an internal combustion engine radiator, capable of high-accuracy, high-response detection of radiator malfunction, particularly of malfunction of a thermostat incorporated in a radiator.
To achieve this object, the invention provides a system for detecting malfunction of an internal combustion engine radiator comprising: engine operating condition detecting means for detecting operating conditions of the engine including at least a coolant temperature; engine-start-time coolant temperature determining means for determining an engine-start-time coolant temperature at starting of the engine based on at least the detected coolant temperature; thermal load parameter determining means for determining a parameter indicative of thermal load contributing to a rise of the coolant temperature based on the detected engine operating conditions; estimated coolant temperature calculating means for calculating an estimated coolant temperature based on at least the determined engine-start-time coolant temperature and the determined parameter indicative of thermal load; and radiator malfunction discriminating means for comparing the detected coolant temperature and the calculated estimated coolant temperature with predetermined values respectively and for discriminating whether the radiator malfunctions based results of comparison.
REFERENCES:
patent: 4069712 (1978-01-01), Armstrong et al.
patent: 4682493 (1987-07-01), Tenenbaum
patent: 5018484 (1991-05-01), Naitoh
patent: 5521581 (1996-05-01), Prouix
patent: 5526871 (1996-06-01), Musser et al.
patent: 5656771 (1997-08-01), Beswick et al.
patent: 5708412 (1998-01-01), Prouix
patent: 5738049 (1998-04-01), Ninomiya
patent: 6-213117 (1994-08-01), None
Hashimoto Akira
Isobe Takashi
Koike Yuzuru
Niki Manabu
Arent Fox Kintner & Plotkin & Kahn, PLLC
Honda Giken Kogyo Kabushiki Kaisha
McCall Eric S.
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