Method and system for detecting a presence of a block heater in an automobile

• US 8,140,246 B1
• Filed: 10/25/2010
• Issued: 03/20/2012
• Est. Priority Date: 10/25/2010
• Status: Active Grant

• Current Assignee: Toyota Motor Corporation
• Original Assignee: Toyota Motor Engineering & Manufacturing North America Incorporated (Toyota Motor Corporation)
• Inventors: Manchanda, Ashim
• Primary Examiner(s): HUYNH, HAI H
• Application Number:
  US12/911,669
• Time in Patent Office: 512 Days
• Field of Search: 123/41.14, 123/41.15, 123/142.5 R, 123/142.5 E, 123/198.D, 701/113, 701/107
• US Class Current: 701/107
• CPC Class Codes: F01P 11/16 concerning coolant temperature F01P11/20 takes precedence
• CPC Class Codes: F01P 2025/08 Temperature
• CPC Class Codes: F01P 2031/00 Fail safe
• CPC Class Codes: F01P 2037/02 starting
• CPC Class Codes: F02D 2200/021 Engine temperature
• CPC Class Codes: F02D 2200/0414 Air temperature
• CPC Class Codes: F02D 41/222 relating to the failure of sensors or parameter detection devices
• CPC Class Codes: F02N 19/10 by heating of engine coolants
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

The present invention relates to a method and system for detecting a presence of a block heater in an automobile. In one embodiment, an automobile includes an engine, a radiator, an engine coolant temperature (“ECT”) sensor, and/or an engine control unit (“ECU”). The radiator delivers coolant to the engine to cool the engine. The ECT sensor is located in a path of the coolant and determines ECT data. The ECU determines a temperature difference between a current maximum temperature of the engine coolant temperature data at a first time period and a current minimum temperature of the engine coolant temperature data at a second time period after the first time period. When the temperature difference is greater than a predetermined temperature threshold, the ECU determines that the block heater is present. When the block heater is present, the ECU masks any engine malfunction detections.

Claims

1. A method for detecting an engine malfunction comprising:

detecting, using an engine coolant temperature sensor, engine coolant temperature data;

determining, using an engine control unit, a maximum temperature of the engine coolant temperature data at a first time period;

determining, using the engine control unit, a minimum temperature of the engine coolant temperature data at a second time period after the first time period;

determining, using the engine control unit, a temperature difference between the maximum temperature and the minimum temperature;

determining, using the engine control unit, a presence of a block heater using the temperature difference;

detecting, using the engine control unit, an engine malfunction, when the block heater is determined to not be present; and

masking, using the engine control unit, the detection of the engine malfunction when the block heater is determined to be present.

2. The method of claim 1 wherein the step of determining, using the engine control unit, the presence of the block heater using the temperature difference includes comparing the temperature difference with a predetermined temperature threshold, and determining that the block heater is present when the temperature difference is greater than the predetermined temperature threshold.

3. The method of claim 2 wherein the predetermined temperature threshold is between approximately 1.25°

C. and 3.125°

C.

4. The method of claim 1 wherein the engine coolant temperature data includes temperature data from a start of an engine.

5. The method of claim 1 wherein the step of masking, using the engine control unit, the detection of the engine malfunction when the block heater is determined to be present includes masking a generation of a diagnostic trouble code.

6. The method of claim 1 wherein an initial engine coolant temperature data of the engine coolant temperature data is an average of a temperature when a user indicates that an engine should be started, and a start of the engine.

7. The method of claim 1 wherein the step of determining, using the engine control unit, the maximum temperature of the engine coolant temperature data at the first time period includes

initializing a current maximum temperature;

detecting a current temperature;

comparing the current maximum temperature to the current temperature; and

updating the current maximum temperature to the current temperature when the current temperature is greater than the maximum temperature.

8. The method of claim 7 wherein the step of determining, using the engine control unit, the minimum temperature of the engine coolant temperature data at the second time period after the first time period includes

initializing a current minimum temperature;

comparing a current minimum temperature to the current temperature; and

updating the current minimum temperature to the current maximum temperature when the current maximum temperature is updated, and updating the current minimum temperature to the current temperature when the current temperature is less than the current minimum temperature.

9. The method of claim 8 further comprising

determining that the current maximum temperature is the maximum temperature of the engine coolant temperature when a predetermined time period has lapsed;

and

determining that the current minimum temperature is the minimum temperature of the engine coolant temperature when a predetermined time period has lapsed.

10. A method for determining a presence of a block heater in an automobile comprising:

detecting, using an engine coolant temperature sensor, engine coolant temperature data;

determining, using an engine control unit, a maximum temperature of the engine coolant temperature data at a first time period;

determining, using the engine control unit, a minimum temperature of the engine coolant temperature data at a second time period after the first time period;

determining, using the engine control unit, a temperature difference between the maximum temperature and the minimum temperature;

comparing, using the engine control unit, the temperature difference with a predetermined temperature threshold; and

determining, using the engine control unit, that the block heater is present when the temperature difference is greater than the predetermined temperature threshold.

11. The method of claim 10 wherein the predetermined temperature threshold is between approximately 1.25°

C. and 3.125°

C.

12. The method of claim 10 wherein an initial engine coolant temperature data of the engine coolant temperature data is an average of a temperature when a user indicates that an engine should be started, and a start of the engine.

13. The method of claim 10 wherein

the step of determining, using the engine control unit, the maximum temperature of the engine coolant temperature data at the first time period includes

initializing a current maximum temperature,

detecting a current temperature,

comparing the current maximum temperature to the current temperature, and

updating the current maximum temperature to the current temperature when the current temperature is greater than the maximum temperature;

and

the step of determining, using the engine control unit, the minimum temperature of the engine coolant temperature data at the second time period after the first time period includes

initializing a current minimum temperature,

comparing a current minimum temperature to the current temperature, and

updating the current minimum temperature to the current maximum temperature when the current maximum temperature is updated, and updating the current minimum temperature to the current temperature when the current temperature is less than the current minimum temperature.

14. The method of claim 13 further comprising

determining that the current maximum temperature is the maximum temperature of the engine coolant temperature when a predetermined time period has lapsed;

and

determining that the current minimum temperature is the minimum temperature of the engine coolant temperature when a predetermined time period has lapsed.

15. An automobile comprising:

an engine including an engine block;

a radiator hose connected to the engine block and configured to transport engine coolant;

an engine coolant temperature sensor located in a path of the engine coolant and configured to detect engine coolant temperature data; and

an engine control unit connected to the engine coolant temperature sensor and configured to;

determine a maximum temperature of the engine coolant temperature data at a first time period,

determine a minimum temperature of the engine coolant temperature data at a second time period after the first time period,

determine a temperature difference between the maximum temperature and the minimum temperature,

compare the temperature difference with a predetermined temperature threshold, and

determine that a block heater is present when the temperature difference is greater than the predetermined temperature threshold.

16. The automobile of claim 15 wherein the predetermined temperature threshold is between approximately 1.25°

C. and 3.125°

C.

17. The automobile of claim 15 wherein an initial engine coolant temperature data of the engine coolant temperature data is an average of a temperature when a user indicates that an engine should be started, and a start of the engine.

18. The automobile of claim 15 wherein the engine control unit is further configured to:

initialize a current maximum temperature using the engine coolant temperature data,

determine the current temperature from the engine coolant temperature data,

compare the current maximum temperature to the current temperature, and

update the current maximum temperature to the current temperature when the current temperature is greater than the maximum temperature.

19. The automobile of claim 18 wherein the engine control unit is further configured to:

initialize a current minimum temperature,

compare a current minimum temperature to the current temperature, and

update the current minimum temperature to the current maximum temperature when the current maximum temperature is updated, and update the current minimum temperature to the current temperature when the current temperature is less than the current minimum temperature.

20. The automobile of claim 18 wherein the engine control unit is further configured to:

determine that the current maximum temperature is the maximum temperature of the engine coolant temperature when a predetermined time period has lapsed, and

determine that the current minimum temperature is the minimum temperature of the engine coolant temperature when the predetermined time period has lapsed.