Method and system for engine cooling system control

Patent metadata

Field	Value
Publication number	US-2016186648-A1
Application number	US-201414583393-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 echo times of an ultrasonic signal transmitted by a sensor positioned in a recess at the bottom of the vertical standpipe. Engine power is limited differently based on distinct coolant level states determined based on a change in level of coolant in the reservoir over a duration.

First claim

1 . A method, comprising:
estimating fluid level in a coolant reservoir based on a sensor coupled in a vertical standpipe aligned parallel to the reservoir, the standpipe fluidically coupled to the reservoir at each of a top and bottom location; and limiting engine power based on the estimated fluid level.

2 . The method of claim 1 , wherein limiting based on the estimated fluid level includes limiting based on the estimated level relative to each of a first, upper threshold and a second, lower threshold.

3 . The method of claim 2 , wherein the limiting includes, limiting by a first amount when the estimated fluid level is below the first threshold and above the second threshold; and limiting by a second, different amount when the estimated fluid level is below each of the first and second threshold.

4 . The method of claim 3 , when the second amount is larger than the first amount, and wherein the second amount if adjusted based on a duration for which the estimated fluid level remains below the second threshold.

5 . The method of claim 4 , further comprising, indicating degradation based on the estimated fluid level.

6 . The method of claim 5 , wherein the indicating includes setting a first diagnostic code when the estimated fluid level is above the first threshold, setting a second diagnostic code when the estimated fluid level is below the first threshold and above the second threshold, and setting a third diagnostic code when the estimated fluid level is below each of the first and second threshold.

7 . The method of claim 1 , wherein the estimating fluid level in a coolant reservoir based on a sensor includes transmitting an ultrasonic signal from the sensor towards the top of the standpipe, receiving an echo of the ultrasonic signal at the sensor upon reflection off a cap coupled to the top of the standpipe; estimating a duration elapsed since the transmission of the ultrasonic signal and receipt of the echo at the sensor, and estimating the fluid level in the coolant reservoir based on the estimated duration.

8 . The method of claim 7 , further comprising, predicting fluid slosh based on vehicle motion, and adjusting the estimated fluid level with a compensation term based on the predicted fluid slosh.

9 . The method of claim 8 , further comprising, estimating actual fluid slosh based on a transient change in sensor output, and wherein the compensation term is based on the predicted fluid slosh relative to the estimated actual fluid slosh.

10 . A method for an engine, comprising:
differentiating between states of a fluid level in a coolant reservoir based on output from a sensor coupled in at a bottom-level of an internal recess of a vertical standpipe, the standpipe positioned adjusted to the reservoir and further fluidically coupled to the reservoir at each of a top and bottom location, the output estimated over a duration.

11 . The method of claim 10 , wherein the duration is adjusted based on engine coolant temperature, the duration decreased as engine coolant temperature increases.

12 . The method of claim 10 , wherein the differentiating is further based on a change in the sensor output responsive to vehicle motion-induced slosh.

13 . The method of claim 12 , wherein differentiating further based on slosh includes differentiating further based on expected slosh relative to estimated slosh, the expected slosh based on vehicle lateral and longitudinal acceleration, the estimated slosh based on the change in the sensor output.

14 . The method of claim 10 , further comprising, limiting engine power differently based on each state of fluid level in the coolant reservoir.

15 . The method of claim 14 , wherein the states of fluid level include:
a first degraded state where the reservoir is empty; a second degraded state where the reservoir fluid level is low; a third degraded state where the reservoir fluid level is unknown; and a fourth degraded state where the sensor is faulty.

16 . The method of claim 15 , wherein the limiting differently includes:
in response to the first degraded state, limiting engine power by a first amount; in response to the second degraded state, limiting engine power by a second amount in response to the third degraded state, limiting engine power by a third amount, in response to the fourth degraded state, limiting engine power by a fourth amount.

17 . The method of claim 10 , wherein the differentiating is further based on one or more of coolant temperature and exhaust temperature.

18 . A coolant system coupled in a vehicle, comprising:
a coolant overflow container including a recess for holding fluid; a vertical, hollow tube having an internal recess, the tube positioned adjacent to the container such that a bottom-most level of the container is above a bottom-most level of the internal recess of the tube; a first hose fluidly coupling a top portion of the container to a top portion of the vertical tube; and a second hose fluidly coupling the bottom-most level of the container to a bottom portion of the vertical tube at a location above the bottom-most level of the internal recess, wherein a level of fluid in the container equilibrates with a level of fluid in the vertical tube; a first sensor positioned within the internal recess; a second sensor coupled to the vehicle and external to the vertical tube for estimating a vehicle motion parameter; and a processor communicatively coupled to the sensor in the internal recess.

19 . The system of claim 18 , wherein the processor is configured with computer readable instructions for:
estimating a fluid level in the vertical tube based on output from the first sensor; adjusting the estimated fluid level based on output from the second sensor; inferring a fluid level in the container based on the adjusted estimate of fluid level in the vertical tube; and limiting engine power based on the inferred fluid level relative to each of a upper and lower threshold, wherein the fluid level in the vertical tube is estimated over a duration that is based on engine coolant temperature, and wherein the inferred fluid level is further adjusted based on a change in the estimated fluid level over the duration.

20 . The system of claim 18 , wherein adjusting the estimated fluid level based on output from the second sensor includes estimating an expected slosh based on the output of the second sensor, calculating an actual slosh based on the output of the first sensor, and adjusting the estimated fluid level with a compensation term based on actual slosh relative to expected slosh, and wherein estimating a fluid level in the vertical tube based on output from the first sensor includes periodically transmitting a signal from the first sensor towards a top of the tube; receiving, at the sensor, an echo of each transmitted signal upon reflection off the top of the vertical tube; estimating an average duration elapsed between the transmitting and the receiving; and estimating the fluid level based on the average duration.

Assignees

• Ford Global Tech Llc

Inventors

• Rollinger John Eric
• Willard Karen
• Giunta Michael Joseph
• Wade Robert Andrew
• Ibrahim Samer
• Dietrich Casey
• Gerow Matt

Classifications

• G01F23/0046

  with a stationary probe, where a liquid specimen is separated from the mean mass and measured (by gauge glasses G01F23/02) · CPC title

• G01F22/00

  Methods or apparatus for measuring volume of fluids or fluent solid material, not otherwise provided for · CPC title

• F01P2025/70

  Level · CPC title

• B60W10/00

  Conjoint control of vehicle sub-units of different type or different function (for propulsion of purely electrically-propelled vehicles with power supplied within the vehicle B60L50/00 - B60L58/00) · CPC title

• F01P11/18 Primary

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