DIAGNOSTIC DEVICE FOR TEMPERATURE SENSOR

• US 20140185647A1
• Filed: 12/04/2013
• Published: 07/03/2014
• Est. Priority Date: 12/28/2012
• Status: Active Grant

• Current Assignee: Subaru Corp.
• Original Assignee: Fuji Jukogyo KK (Subaru Corp.)
• Inventors: KINOSHITA, Takahiro
• Granted Patent: US 9,074,949 B2
• Time in Patent Office: Days
• US Class Current: 374/4
• CPC Class Codes: G01K 15/007 Testing
• CPC Class Codes: G01K 2205/00 Application of thermometers in motors, e.g. of a vehicle

Abstract

A diagnostic device for a temperature sensor is provided in a power transfer device that transfers drive power generated by a drive power source in a vehicle. The diagnostic device includes: a warm-up state determining unit to determine whether the drive power source is in a predetermined warm-up completion state; and a low temperature offset malfunction determining unit to determine a low temperature offset malfunction in the temperature sensor when the warm-up state determining unit determines that the warm-up completion state is established, and the detected value from the temperature sensor is lower than a predetermined low temperature threshold.

Claims

1. A diagnostic device for a temperature sensor provided in a power transfer device that transfers drive power generated by a drive power source in a vehicle, the diagnostic device for a temperature sensor comprising:

a warm-up state determining unit to determine whether or not the drive power source is in a predetermined warm-up completion state; and

a low temperature offset malfunction determining unit to determine a low temperature offset malfunction in the temperature sensor when the warm-up state determining unit determines that the warm-up completion state is established, and the detected value from the temperature sensor is lower than a predetermined low temperature threshold.

2. The diagnostic device for a temperature sensor according to claim 1, wherein the warm-up state determining unit determines the warm-up completion state when an accumulated time of a state in which an estimated heat amount from the drive power source is at or above a predetermined value is at or above a predetermined value.

3. The diagnostic device for a temperature sensor according to claim 1, further comprising:

a high heat state determining unit to determine whether or not the drive power source is in a predetermined high heat state; and

a high temperature offset malfunction determining unit to determine a high temperature offset malfunction in the temperature sensor when the high heat state determining unit determines that the high heat state is not established, and the detected value from the temperature sensor is higher than a predetermined high temperature threshold.

4. The diagnostic device for a temperature sensor according to claim 2, further comprising:

a high heat state determining unit to determine whether or not the drive power source is in a predetermined high heat state; and

a high temperature offset malfunction determining unit to determine a high temperature offset malfunction in the temperature sensor when the high heat state determining unit determines that the high heat state is not established, and the detected value from the temperature sensor is higher than a predetermined high temperature threshold.

6. The diagnostic device for a temperature sensor according to claim 3, wherein the high temperature offset malfunction determining unit determines the high temperature offset malfunction when the high heat state determining unit determines that the high heat state is not established, and an accumulated time of a state in which the detected value from the temperature sensor is higher than the predetermined high temperature threshold is at or above a predetermined value.

7. The diagnostic device for a temperature sensor according to claim 4, wherein the high temperature offset malfunction determining unit determines the high temperature offset malfunction when the high heat state determining unit determines that the high heat state is not established, and an accumulated time of a state in which the detected value from the temperature sensor is higher than the predetermined high temperature threshold is at or above a predetermined value.

5. A diagnostic device for a temperature sensor provided in a power transfer device that transfers drive power generated by a drive power source in a vehicle, the diagnostic device for a temperature sensor comprising:

a high heat state determining unit to determine whether or not the drive power source is in a predetermined high heat state; and

a high temperature offset malfunction determining unit to determine a high temperature offset malfunction in the temperature sensor when the high heat state determining unit determines that the high heat state is not established, and the detected value from the temperature sensor is higher than a predetermined high temperature threshold.

8. The diagnostic device for a temperature sensor according to claim 5, wherein the high temperature offset malfunction determining unit determines the high temperature offset malfunction when the high heat state determining unit determines that the high heat state is not established, and an accumulated time of a state in which the detected value from the temperature sensor is higher than the predetermined high temperature threshold is at or above a predetermined value.

9. A diagnostic device for a temperature sensor provided in a power transfer device that transfers drive power generated by a drive power source in a vehicle, the diagnostic device for a temperature sensor comprising:

a low ambient temperature temperature-estimating unit to calculate an estimated temperature of a measured object under conditions of predetermined low temperatures; and

a low temperature offset malfunction determining unit to determine a low temperature offset malfunction in the temperature sensor when the estimated temperature calculated by the low ambient temperature temperature-estimating unit is at or above a predetermined value, and the actual value of the measured object detected by the temperature sensor is at or below a previously set low temperature offset malfunction determination value.

10. The diagnostic device for a temperature sensor according to claim 9, wherein the low temperature offset malfunction determining unit determines the low temperature offset malfunction when a state in which the actual value is at or below the low temperature offset malfunction determination value continues for at least a predetermined amount of time.

11. The diagnostic device for a temperature sensor according to claim 9, further comprising:

a high ambient temperature temperature-estimating unit to calculate an estimated temperature of a measured object under conditions of predetermined high temperatures; and

a high temperature offset malfunction determining unit to determine the high temperature offset malfunction in the temperature sensor when the actual value of the measured object detected by the temperature sensor is at least a predetermined value higher than the estimated temperature calculated by the high ambient temperature temperature-estimating unit.

12. The diagnostic device for a temperature sensor according to claim 10, further comprising:

a high ambient temperature temperature-estimating unit to calculate an estimated temperature of a measured object under conditions of predetermined high temperatures; and

a high temperature offset malfunction determining unit to determine the high temperature offset malfunction in the temperature sensor when the actual value of the measured object detected by the temperature sensor is at least a predetermined value higher than the estimated temperature calculated by the high ambient temperature temperature-estimating unit.

14. The diagnostic device for a temperature sensor according to claim 11, wherein the high temperature offset malfunction determining unit determines the high temperature offset malfunction when a state in which the actual value is at least a predetermined value higher than the estimated temperature calculated by the high ambient temperature temperature-estimating unit continues for at least a predetermined amount of time.

15. The diagnostic device for a temperature sensor according to claim 12, wherein the high temperature offset malfunction determining unit determines the high temperature offset malfunction when a state in which the actual value is at least a predetermined value higher than the estimated temperature calculated by the high ambient temperature temperature-estimating unit continues for at least a predetermined amount of time.

13. A diagnostic device for a temperature sensor provided in a power transfer device that transfers drive power generated by a drive power source in a vehicle, the diagnostic device for a temperature sensor comprising:

a high ambient temperature temperature-estimating unit to calculate an estimated temperature of a measured object under conditions of predetermined high temperatures; and

a high temperature offset malfunction determining unit to determine the high temperature offset malfunction in the temperature sensor when the actual value of the measured object detected by the temperature sensor is at least a predetermined value higher than the estimated temperature calculated by the high ambient temperature temperature-estimating unit.

16. The diagnostic device for a temperature sensor according to claim 13, wherein the high temperature offset malfunction determining unit determines the high temperature offset malfunction when a state in which the actual value is at least a predetermined value higher than the estimated temperature calculated by the high ambient temperature temperature-estimating unit continues for at least a predetermined amount of time.