Methods and systems for an exhaust-gas recirculation valve

Patent metadata

Field	Value
Publication number	US-10941735-B2
Application number	US-201916252175-A
Country	US
Kind code	B2
Filing date	Jan 18, 2019
Priority date	Jan 22, 2018
Publication date	Mar 9, 2021
Grant date	Mar 9, 2021

Abstract

Methods and systems are provided for adjusting an EGR valve operation based on results from an EGR valve diagnostic. In one example, a method may include executing the EGR valve diagnostic during an engine deactivation, wherein the EGR valve diagnostic estimates an EGR valve stickiness used to adjust the EGR valve operation.

First claim

The invention claimed is:

1. A method comprising:
executing an EGR valve diagnostic following an engine deactivation to adjust an EGR valve operation, wherein the EGR valve diagnostic calculates three or more of a breakaway value, a holding power value, a hang time value, a travel time value, and a travel speed value as an EGR valve is actuated from a resting position, to a predetermined position, and back to the resting position.

2. The method of claim 1 , wherein the breakaway value is equal to an amount of power used to actuate the EGR valve from the resting position to the predetermined position.

3. The method of claim 1 , wherein the holding power value is equal to an amount of power used to hold the EGR valve in the predetermined position.

4. The method of claim 1 , wherein the hang time value is calculated in response to power supplied to an actuator of the EGR valve being adjusted to zero when the EGR valve is in the predetermined position, the hang time being equal to a delay from when power supplied to the actuator of EGR valve is adjusted to zero to when the EGR valve begins to move from the predetermined position to the resting position.

5. The method of claim 1 , wherein the travel distance time is equal to a time used for the EGR valve to travel from the predetermined position to the resting position.

6. The method of claim 1 , wherein the travel speed value is equal to a travel speed of the EGR valve travelling from the predetermined position to the resting position.

7. The method of claim 1 , wherein the resting position is between a fully closed position and a fully open position, and where the resting position comprises where zero power is supplied to an actuator of the EGR valve.

8. The method of claim 1 , wherein the EGR valve operation is adjusted during a subsequent engine activation, and where the EGR valve operation is adjusted to compensate a valve stickiness value equal to a combination of the breakaway value, the holding power value, the hang time value, the travel time value, and the travel speed value.

9. A system comprising:
an engine comprising an exhaust-gas recirculation passage fluidly coupling an exhaust passage to an intake passage, wherein exhaust gas from the exhaust-gas recirculation passage to the intake passage is adjusted via an exhaust-gas recirculation valve; and
a controller with computer-readable instructions stored on non-transitory memory thereof that when executed enable the controller to:
execute an exhaust-gas recirculation valve diagnostic in response to an engine being deactivated, wherein the exhaust-gas recirculation valve diagnostic comprises:
setting a power supply to an actuator of the exhaust-gas recirculation valve to zero;
increasing the power supply to the actuator of the exhaust-gas recirculation valve to actuate the exhaust-gas recirculation valve to a predetermined position;
calculating a breakaway value equal to the power supply used to actuate the exhaust-gas recirculation valve to the predetermined position;
holding the exhaust-gas recirculation valve at the predetermined position;
calculating a holding value equal to a holding power supply used to hold the exhaust-gas recirculation valve in the predetermined position;
decreasing the holding power supply to zero;
measuring a hang time value equal to a time elapsed between decreasing the holding power supply to zero and the exhaust-gas recirculation valve moving out of the predetermined position;
calculating a travel time of the exhaust-gas recirculation valve from the predetermined position to a resting position;
calculating a travel speed of the exhaust-gas recirculation valve from the predetermined position to the resting position; and
combining the breakaway value, the holding value, the hang time value, the travel time, and the travel speed to estimate a stickiness value of the EGR valve, further comprising adjusting an EGR valve operation during a subsequent engine activation based on the stickiness value.

10. The system of claim 9 , wherein the instructions further enable the controller to determine one or more of if an exhaust-gas valve position is known, if a battery state of charge is greater than or equal to a threshold state of charge, if an engine operation duration prior to the engine being deactivated was greater than a threshold amount of time, if an end-stop learning was completed, and if a coolant temperature is greater than a threshold temperature prior to the exhaust-gas recirculation valve diagnostic, the end-stop learning comprises learning one or more of a resting position, a fully closed position, and a fully open position of the exhaust-gas recirculation valve, and where the resting position is equal to a position of the exhaust-gas recirculation valve where zero power is supplied to an actuator of the exhaust-gas recirculation valve, wherein the resting position is learned via opening the exhaust-gas recirculation valve via supplying an amount of power to the actuator of the exhaust-gas recirculation valve, decreasing the amount of power to zero, and sensing a valve speed equaling zero, wherein the resting position corresponds to when the valve speed of the exhaust-gas recirculation valve is equal to zero.

11. The system of claim 10 , further comprising where the controller is a PID controller with a feed-forward term.

12. The system of claim 11 , wherein a p-term, an i-term, and a d-term are adjusted via a diagnostic factor selected from one or more of the breakaway value, the holding value, the hang time value, the travel time, and the travel speed.

13. The system of claim 12 , wherein the diagnostic factor is equal to an average of one or more of the breakaway value, the holding value, the hang time value, the travel time, and the travel speed.

14. The system of claim 9 , wherein the stickiness value increases in response to one or more of the breakaway value increasing, the holding value increasing, the hang time value increasing, the travel time value increasing, and the travel speed value decreasing, and where a magnitude of adjusting the EGR valve operation increases as the stickiness value increases.

15. The system of claim 14 , wherein the EGR valve operation adjustments include increasing power supply to the EGR valve, wherein the increasing the power supply occurs when the EGR valve is moving in an opening direction, a closing direction, or both.

16. A method comprising:
actuating an EGR valve from a resting position to a predetermined position during an engine deactivation;
calculating a breakaway power used to actuate the EGR valve from the resting position to the predetermined position;
holding the EGR valve in the predetermined position;
calculating a holding power used to hold the EGR valve in the predetermined position;
actuating the EGR valve from the predetermined position to the resting position;
calculating a hang time for the EGR valve to move out of the predetermine position;
calculating a travel time and a travel speed of the EGR valve from the predetermined position to the resting position; and
combining the breakaway value, the holding value, the hang time value, the travel time, and the travel speed to estimate a stickiness value of the EGR valve, further comprising adjusting an EGR valve operation during a subsequent engine activation based on the stickiness value.

17. The method of claim 16 , further comprising measuring an impact of each of the breakaway value, the holding value, the hang time value, the travel time, and the travel speed on the stickiness value, and where adjusting the EG

Assignees

• Ford Global Tech Llc

Inventors

• Halleron Ian
• Szilagyi Zoltan
• Dixon Jon

Classifications

• F02D21/08

  the other gas being the exhaust gas of engine · CPC title

• F02M2026/001

  Arrangements; Control features; Details · CPC title

• F02D2200/02

  the parameters being related to the engine · CPC title

• F02M26/49 Primary

  Detecting, diagnosing or indicating an abnormal function of the EGR system · CPC title

• F02D41/0077

  Control of the EGR valve or actuator, e.g. duty cycle, closed loop control of position (EGR valve position sensor F02M26/48) · CPC title