Cooling system diagnostic method

• US 9,790,842 B2
• Filed: 02/09/2015
• Issued: 10/17/2017
• Est. Priority Date: 02/09/2015
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Dudar, Aed M., Jentz, Robert Roy
• Primary Examiner(s): LATHERS, KEVIN ANTHONY
• Application Number:
  US14/617,609
• Publication Number:
  US 20160230644A1
• Time in Patent Office: 981 Days
• CPC Class Codes: F01P 11/16 concerning coolant temperature F01P11/20 takes precedence
• CPC Class Codes: F01P 11/18 concerning coolant pressure, coolant flow, or liquid-coolant level

Abstract

A method for operating an engine cooling system is provided. The method includes monitoring a coolant temperature profile after engine shut-down and indicating a low coolant level based on the coolant temperature profile determined after engine shut-down.

Claims

1. A method for operating an engine cooling system comprising:

after an engine shut-down, sending power to a controller;

at the controller, receiving a temperature signal from an engine temperature sensor and determining a coolant temperature profile based on the temperature signal; and

adjusting engine power output during a subsequent engine start-up based on the coolant temperature profile determined after engine shut-down.

2. The method of claim 1, wherein adjusting engine power output during the subsequent engine start-up comprises one or more of reducing engine power output during the subsequent start-up, inhibiting engine operation until coolant temperature is above a threshold, limiting boost provided to the engine by a compressor during the subsequent start-up, decreasing airflow to the engine during the subsequent start-up, limiting engine fuel injection, and inhibiting of spark retard during the subsequent start-up.

3. The method of claim 1, further comprising discontinuing power transfer to the controller before sending power to the controller and determining the coolant temperature profile.

4. The method of claim 1, wherein the determination of the coolant temperature profile is also based on environmental conditions.

5. The method of claim 1, where the coolant temperature profile is compared to a predicted coolant temperature profile to determine whether a coolant level is lower than a threshold.

6. The method of claim 5, where the predicted coolant temperature profile is generated based on an exponential decay.

7. The method of claim 1, further comprising, at the controller, during engine combustion operation, determining a coolant level based on the temperature signal from the temperature sensor in the engine.

8. The method of claim 1, where determining the coolant temperature profile is initiated in response to a climate control unit generating heat less than a threshold value.

9. The method of claim 1, further comprising, triggering a low coolant level indicator in a cabin of a vehicle based on the coolant temperature profile determined after engine shut-down.

10. The method of claim 9, further comprising increasing an output of a heat exchanger fan during the subsequent engine start-up in response to triggering of the low coolant level indicator.

11. An engine cooling system comprising:

a cooling circuit circulating coolant through passages traversing an engine;

a heat exchanger coupled to the cooling circuit;

a temperature sensor coupled to at least one of the cooling circuit and the engine; and

a controller configured to;

after engine shut-down, receive power;

determine a coolant temperature profile based on a signal sent from the temperature sensor; and

adjust engine power output during a subsequent start-up based on the coolant temperature profile determined after engine shut-down.

12. The engine cooling system of claim 11, where the coolant temperature profile is compared to a predicted coolant temperature profile to determine how to adjust engine power during the subsequent start-up.

13. The engine cooling system of claim 12, where the predicted coolant temperature profile is included in a set of predicted coolant temperature profiles that are predicted and stored in memory in the controller.

14. The engine cooling system of claim 11, where the controller is configured to receive power after engine shut-down and determine the coolant temperature profile in response to one of an engine shut-down event and a cabin heat exchanger coupled to the cooling circuit generating heat less than a threshold value.

15. A method for operating an engine cooling system comprising:

after engine shut-down and vehicle off condition, maintaining power to a controller that determines a coolant temperature profile over time;

comparing the coolant temperature profile to a predicted coolant temperature profile; and

if a deviation between the determined coolant temperature profile and the predicted coolant temperature profile exceeds a threshold value, triggering a low coolant level indicator in a vehicle cabin based on the coolant temperature profile determined after engine shut-down.

16. The method of claim 15, where comparing the coolant temperature profile to the predicted coolant temperature profile includes determining differences between a plurality of coolant temperatures in each profile and summing the temperature differences to determine if the profile deviation is greater than the threshold value.

17. The method of claim 15, where the coolant temperature profile is determined in direct response to an engine shut-down event and comparing the coolant temperature profile to the predicted coolant temperature profile is implemented during engine shut-down.

18. The method of claim 15, further comprising after engine shut-down and before determining the coolant temperature profile, sending power to the controller and inhibiting power transfer to the controller after triggering the low coolant level indicator.