Method and system for engine cooling system control

Patent metadata

Field	Value
Publication number	US-2016186649-A1
Application number	US-201414583414-A
Country	US
Kind code	A1
Filing date	Dec 26, 2014
Priority date	Dec 26, 2014
Publication date	Jun 30, 2016
Grant date	—

Abstract

Methods and systems are providing for improving engine coolant level estimation to reduce engine overheating. The level of fluid in a coolant overflow reservoir is inferred based on the fluid level in a hollow vertical standpipe fluidically coupled to the reservoir at top and bottom locations, while the fluid level in the standpipe is estimated based on output from an ultrasonic signal transmitted by a sensor positioned in a recess at the bottom of the vertical standpipe. The sensor uses a combination of raw echo times and processed fluid level data to estimate the fluid level accurately and reliably.

First claim

1 . A method, comprising:
receiving each of unprocessed, raw echo times and processed fluid level data from a sensor coupled to a vertical tube, the tube positioned external to and fluidically coupled to a coolant reservoir at each of a top and bottom region; and generating a fluid level estimate based on the raw echo times and vehicle sensor data during a first condition; and generating the fluid level estimate based on the processed data during a second condition.

2 . The method of claim 1 , wherein the sensor transmits a signal in the vertical tube and receives an echo of the transmitted signal, and wherein the unprocessed raw echo times includes an echo time elapsed between the transmitting of the signal from the sensor and the receipt of the echo at the sensor.

3 . The method of claim 2 , wherein the sensor transmits the signal periodically with a frequency and at a power setting, each of the frequency and the power setting of the transmitted signal based on the echo time of a previous transmitted signal.

4 . The method of claim 3 , wherein the raw echo times includes one or more of a first order and second order harmonic echo time and wherein the processed fluid level data includes a fluid level estimated based on the raw echo time.

5 . The method of claim 4 , wherein the raw echo times further includes a total number of echoes and an echo time of individual echoes received over a duration relative to the frequency of transmitting the signal periodically, and wherein the processed data includes the fluid level estimated based on a number of echoes with signal higher than a threshold level received over the duration.

6 . The method of claim 5 , further comprising indicating degradation of the sensor based on the raw echo times relative to the processed fluid level data.

7 . The method of claim 6 , wherein the sensor is a first sensor including a piezoelectric element, and wherein the degradation is further indicated based on fluid temperature estimated by a temperature sensor coupled to the first sensor.

8 . A method, comprising:
periodically transmitting a sensor signal from a bottom to a top of a vertical tube positioned adjacent to a coolant reservoir, the tube fluidically coupled to the reservoir at each of the bottom and the top such that a vertical tube bottom is positioned lower than a reservoir bottom; and generating each of raw data and processed data of an echo of the transmitted signal at the sensor.

9 . The method of claim 8 , further comprising estimating a fluid level of the coolant reservoir based on each of the raw data and the processed data.

10 . The method of claim 9 , further comprising, estimating a change in the estimated fluid level due to vehicle motion induced slosh based on each of the raw data and the processed data.

11 . The method of claim 10 , wherein the coolant reservoir is coupled to a vehicle engine coolant system, the method further comprising, indicating degradation of the coolant system based on each of the raw data and the processed data.

12 . The method of claim 11 , further comprising, adjusting a power output of the sensor based on each of the raw data and the processed data.

13 . The method of claim 8 , wherein the raw data includes a first and second harmonic echo time and wherein the processed data includes a fluid level estimated based on the raw data.

14 . The method of claim 13 , wherein the echo time includes a duration elapsed between transmission of the sensor signal and receipt of the echo.

15 . A coolant system coupled in a vehicle, comprising:
a coolant overflow container containing fluid, the container having a top and a bottom surface; a vertical, hollow tube containing fluid positioned adjacent to the container, the tube having an internal structure coupled to a bottom portion of the tube such that a bottom-most level of the internal structure is lower than the bottom surface of the container, the internal structure housing a piezoelectric sensor; a first hose fluidly coupling a top portion of the vertical tube to the top surface of the container; a second hose fluidly coupling the bottom portion of the tube to the bottom surface of the container at a location above the bottom-most level of the internal structure such that a level of fluid in the container equilibrates with a level of fluid in the vertical tube via fluid transfer between the first and second hoses; and a processor communicatively coupled to the sensor, the processor configured with computer readable instructions for:
periodically transmitting a signal from the element towards the top of the tube;
receiving a raw data based on an echo time elapsed between the signal being transmitted by the sensor and an echo of the signal being received at the sensor;
generating processed data including a processed fluid level estimate based on the raw data; and
indicating coolant system degradation based on each of the raw and processed data.

16 . The system of claim 15 , wherein the processor includes further instructions for:
differentiating between different states of coolant system degradation based on each of the raw and processed data, wherein the different states of coolant system degradation include: a first state where the piezoelectric element is degraded; a second state where a fluid level in the container is below a lower threshold; a third state where the fluid level in the container is unknown while the piezoelectric element is not degraded; and a fourth state where the fluid level in the container is above the lower threshold and below an upper threshold.

17 . The system of claim 16 , wherein the processor includes further instructions for:
limiting engine power by different degrees based on the different states of coolant system degradation.

18 . The system of claim 17 , further comprising a motion sensor coupled to the vehicle for estimating a vehicle motion parameter, the processor including further instructions for:
estimating an expected slosh based on an output of the motion sensor; estimating an actual slosh based on the raw echo time; and adjusting the raw echo time based on the expected slosh relative to the actual slosh; and
estimating the fluid level in the container based on the adjusted raw echo time.

19 . The system of claim 15 , wherein the raw data includes a first order and a second order harmonic echo time.

20 . The system of claim 19 , wherein the processor includes further instructions for: adjusting a power of the signal from the element based on detection of the second order harmonic echo time.

Assignees

• Ford Global Tech Llc

Inventors

• Rollinger John Eric
• Jentz Robert Roy
• Goodwin William Russell
• Griffin Chad Everette
• Dietrich Casey
• Gerow Matt
• Thompson Scott Steadmon

Classifications

• G01F23/296 Primary

  Acoustic waves · CPC title

• G01F23/2962 Primary

  Measuring transit time of reflected waves · CPC title

• F01P11/18 Primary

  concerning coolant pressure, coolant flow, or liquid-coolant level · CPC title

• F01P2025/70

  Level · CPC title

• F01P11/14

  Indicating devices; Other safety devices · CPC title