Apparatus for detecting a failure of a thermostat for an engine

• US 20040262411A1
• Filed: 06/01/2004
• Published: 12/30/2004
• Est. Priority Date: 05/30/2003
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Tsukamoto, Toshinori, Gosyo, Eisaku
• Granted Patent: US 7,299,993 B2
• Time in Patent Office: Days
• US Class Current: 236/101.00C
• CPC Class Codes: F01P 11/16 concerning coolant temperature F01P11/20 takes precedence
• CPC Class Codes: F01P 2023/00 Signal processing; Details thereof
• CPC Class Codes: F01P 2023/08 Microprocessor; Microcomputer
• CPC Class Codes: F01P 2025/34 Heat exchanger incoming fluid temperature
• CPC Class Codes: F01P 2025/36 Heat exchanger mixed fluid temperature
• CPC Class Codes: F01P 2031/00 Fail safe

Abstract

An apparatus for detecting a failure of a thermostat provided between an engine and a radiator is provided. The thermostat regulates circulation of cooling water between the engine and the radiator. The apparatus comprises a radiator water temperature sensor disposed on the radiator side relative to the thermostat and a controller. The controller performs a process for detecting a failure of the thermostat based on the output of the radiator water temperature sensor when the engine has reached a desired warm condition. In one example, it is determined whether the engine has reached the desired warm condition based on the output of the engine water temperature sensor that is provided in the engine side relative to the thermostat. In another example, it is determined whether the engine had reached the desired warm condition according to whether a vehicle-related process is activated. In yet another example, it is determined whether the engine has reached the desired warm condition based on an estimated value for the engine water temperature.

Claims

1. An apparatus for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the apparatus comprising:

a first temperature sensor provided on a radiator side relative to the thermostat;

a second temperature sensor provided on an engine side relative to the thermostat; and

a controller configured to;

determine that the engine has reached a desired warm condition if a temperature detected by the second temperature sensor reaches a first predetermined value; and

perform a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in a temperature detected by the first temperature sensor.

2. The apparatus of claim 1, wherein the controller is further configured to:

determine that the engine has reached the desired warm condition if an amount of change in the temperature detected by the second temperature sensor exceeds a second predetermined value before the temperature detected by the second temperature sensor reaches the first predetermined value.

3. An apparatus for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the apparatus comprising:

a temperature sensor provided on a radiator side relative to the thermostat;

a controller configured to;

determine that the engine has reached a desired warm condition if a vehicle-related process that is configured to be performed when the engine has reached the desired warm condition is activated; and

perform a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in a temperature detected by the temperature sensor.

4. An apparatus for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the apparatus comprising:

a temperature sensor provided on a radiator side relative to the thermostat;

a controller configured to;

determine a level of warm condition of the engine;

determine whether the engine has reached the desired warm condition based on the determined level; and

perform a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in a temperature detected by the temperature sensor.

5. An apparatus for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the apparatus comprising:

a temperature sensor provided on a radiator side relative to the thermostat;

a controller configured to;

estimate a temperature of the cooling water based on a heat amount generated from the engine;

determine that the engine has reached a desired warm condition if the estimated temperature reaches a predetermined value; and

perform a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in a temperature detected by the temperature sensor.

6. The apparatus of claim 5,

wherein the controller is further configured to:

estimate a first temperature of the cooling water when a cooling loss is maximum;

estimate a second temperature of the cooling water when the cooling loss is minimum;

determine that the engine has reached a desired warm condition if an amount of change in the second temperature is greater than a predetermined value when the first temperature has reached a temperature that causes the thermostat to open.

7. A method for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the method comprising the steps of:

detecting a first temperature of the cooling water in a radiator side relative to the thermostat;

detecting a second temperature of the cooling water in an engine side relative to the thermostat;

determining that the engine has reached a desired warm condition if the second temperature reaches a first predetermined value; and

performing a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in the first temperature.

8. The method of claim 7, further comprising the step of:

determining that the engine has reached the desired warm condition if an amount of change in the second temperature exceeds a second predetermined value before the second temperature reaches the first predetermined value.

9. A method for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the method comprising the steps of:

detecting a temperature of the cooling water in a radiator side relative to the thermostat;

determining that the engine has reached a desired warm condition if a vehicle-related process that is configured to be performed when the engine has reached the desired warm condition is activated; and

performing a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in the temperature.

10. A method for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the method comprising the steps of:

detecting a temperature of the cooling water in a radiator side relative to the thermostat;

determining a level of warm condition of the engine;

determining whether the engine has reached a desired warm condition based on the determined level; and

performing a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in the temperature.

11. A method for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the method comprising the steps of:

detecting a temperature of the cooling water in a radiator side relative to the thermostat;

estimating a temperature of the cooling water based on a heat amount generated from the engine,

determining that the engine has reached a desired warm condition if the estimated temperature reaches a predetermined value; and

performing a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in the temperature.

12. The method of claim 11, further comprising the steps of:

estimating a first temperature of the cooling water when a cooling loss is maximum;

estimating a second temperature of the cooling water when the cooling loss is minimum; and

determining that the engine has reached the desired warm condition if an amount of change in the second temperature is greater than a predetermined value when the first temperature has reached a temperature that causes the thermostat to open.

13. An apparatus for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the apparatus comprising:

means for detecting a first temperature of the cooling water in a radiator side relative to the thermostat;

means for detecting a second temperature of the cooling water in an engine side relative to the thermostat;

means for determining that the engine has reached a desired warm condition if the second temperature reaches a first predetermined value; and

means for performing a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in the first temperature.

14. The apparatus of claim 13, further comprising:

means for determining that the engine has reached the desired warm condition if an amount of change in the second temperature exceeds a second predetermined value before the second temperature reaches the first predetermined value.

15. An apparatus for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the apparatus comprising:

means for detecting a temperature of the cooling water in a radiator side relative to the thermostat;

means for determining that the engine has reached a desired warm condition if a vehicle-related process that is configured to be performed when the engine has reached the desired warm condition is activated; and

means for performing a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in the temperature.

16. An apparatus for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the apparatus comprising:

means for detecting a temperature of the cooling water in a radiator side relative to the thermostat;

means for determining a level of warm condition of the engine;

means for determining whether the engine has reached a desired warm condition based on the determined level; and

means for performing a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in the temperature.

17. An apparatus for detecting a failure of a thermostat provided between an engine and a radiator, the thermostat regulating circulation of cooling water between the engine and the radiator, the apparatus comprising:

means for detecting a temperature of the cooling water in a radiator side relative to the thermostat;

means for estimating a temperature of the cooling water based on a heat amount generated from the engine;

means for determining that the engine has reached a desired warm condition if the estimated temperature reaches a predetermined value; and

means for performing a failure detection process if it is determined that the engine has reached the desired warm condition, the process detecting a failure of the thermostat based on an amount of change in the detected temperature.

18. The apparatus of claim 17, further comprising:

means for estimating a first temperature of the cooling water when a cooling loss is maximum;

means for estimating a second temperature of the cooling water when the cooling loss is minimum; and

means for determining that the engine has reached the desired warm condition if an amount of change in the second temperature is greater than a predetermined value when the first temperature has reached a temperature that causes the thermostat to open.