METHOD FOR MITIGATING WET-FOULING OF SPARK PLUGS

• US 20170204796A1
• Filed: 01/19/2016
• Published: 07/20/2017
• Est. Priority Date: 01/19/2016
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Dudar, Aed M.
• Granted Patent: US 9,790,874 B2
• Time in Patent Office: Days
• CPC Class Codes: F02D 13/0207 changing valve lift or valve lift and timing
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2041/002 by simultaneous control of throttle and variable valve actuation
• CPC Class Codes: F02D 2200/0404 Throttle position
• CPC Class Codes: F02D 41/0002 Controlling intake air
• CPC Class Codes: F02D 41/0035 to achieve a special effect, e.g. to warm up the catalyst
• CPC Class Codes: F02D 41/004 Control of the valve or purge actuator, e.g. duty cycle, closed loop control of position
• CPC Class Codes: F02D 41/009 using means for generating position or synchronisation signals
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02D 41/064 at cold start F02D41/067 takes precedence
• CPC Class Codes: F02D 41/221 relating to the failure of actuators or electrically driven elements
• CPC Class Codes: F02D 9/105 having a throttle position sensor detection of actuation F02D11/106
• CPC Class Codes: F02M 2025/0881 with means to heat or cool the canister
• CPC Class Codes: F02M 25/0818 having means for pressurising the evaporative emission space
• CPC Class Codes: F02M 25/0836 Arrangement of valves controlling the admission of fuel vapour to an engine, e.g. valve being disposed between fuel tank or absorption canister and intake manifold
• CPC Class Codes: F02M 25/0854 Details of the absorption canister
• CPC Class Codes: F02M 25/089 Layout of the fuel vapour installation
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Methods and systems are provided for the mitigation of wet-fouling of the spark plugs of an engine. In one example, a method may include, after spark plug fouling has been detected prior to an engine start, drawing fresh air through the EVAP system of an engine, heating it, and flowing the heated gas through one or more cylinders of an engine while the engine is not rotating.

Claims

1. A method for an engine system, comprising:

responsive to detecting spark plug fouling prior to an engine start,

transferring heat to a gas in the engine system; and

flowing the heated gas through one or more cylinders of an engine while the engine is not rotating.

2. The method of claim 1, wherein the spark plug fouling comprises wet fouling occurring as a result of a prior engine start attempt.

3. The method of claim 2, wherein detecting the wet spark plug fouling comprises detecting the wet spark plug fouling responsive to one or more of a throttle position during engine cranking of the prior engine start attempt, exhaust gas sensor output during the prior engine start attempt, and a threshold number of prior engine start attempts being reached.

4. The method of claim 1, wherein transferring heat to a gas in the engine system comprises transferring heat to one or more of fuel vapors and fresh air from an evaporative emission control (EVAP) system, and wherein flowing heated gas through one or more cylinders of the engine comprises flowing one or more of the heated fuel vapors and heated fresh air through the one or more cylinders of the engine.

5. The method of claim 4, wherein transferring heat to one or more of the fuel vapors and fresh air comprises transferring heat from an electric heater positioned in the EVAP system to one or more of the fuel vapors and fresh air.

6. The method of claim 5, wherein flowing one or more of heated fuel vapors and heated fresh air from the EVAP system through the one or more cylinders of the engine comprises:

adjusting one or more of engine position and camshaft position to hold each of an intake valve and an exhaust valve of a selected cylinder in a respective open position;

activating a pump of the EVAP system to draw fresh air into a fuel vapor canister of the EVAP system and by the electric heater, the electric heater positioned in the fuel vapor canister; and

flowing the heated fuel vapors and/or heated fresh air through the selected cylinder.

7. The method of claim 6, further comprising opening a canister purge valve and a canister vent valve prior to activating the pump.

8. The method of claim 6, further comprising closing an intake throttle prior to activating the pump.

9. The method of claim 6, further comprising after flowing the heated fuel vapors and/or heated fresh air through the selected cylinder for a threshold duration, further adjusting one or more of engine position and camshaft position to hold each of an intake valve and an exhaust valve of a subsequent cylinder in a respective open position.

10. A system, comprising:

an engine having a cylinder, the cylinder comprising a spark plug, an intake valve, and an exhaust valve;

a variable camshaft timing (VCT) system configured to adjust a position of the intake valve and the exhaust valve;

an evaporative emission control (EVAP) system comprising;

a fuel vapor canister coupled to a fuel tank, coupled to the engine via a canister purge valve, and to atmosphere via a canister vent valve,

a fuel vapor canister heater, and

an evaporative leak detection pump coupled between the fuel vapor canister and atmosphere; and

a controller storing instructions that when executed cause the controller to;

responsive to an indication of wet fouling of the spark plug, prior to an engine start, activate the fuel vapor canister heater, open the canister vent valve and canister purge valve, adjust the VCT system to hold each of the intake valve and the exhaust valve in an open position, and activate the pump to flow heated fresh air and/or fuel vapors through the cylinder and over the spark plug.

11. The system of claim 10, further comprising a throttle to control intake airflow to the engine and a vent blocking valve coupled between the fuel vapor canister and fuel tank, and wherein the controller stores further instructions that when executed cause the controller to, responsive to the indication of wet fouling, close the throttle and close the vent blocking valve.

12. The system of claim 10, wherein the controller stores further instructions that when executed cause the controller to, following the engine start, adjust the throttle based on operator-requested torque, deactivate the fuel vapor canister heater, maintain open the canister vent valve, close the canister purge valve, adjust the VCT system based on engine operating parameters, and deactivate the pump.

13. The system of claim 12, wherein the controller stores further instructions that when executed cause the controller to:

responsive to an indication to perform a fuel vapor canister purge during engine operation, activate the fuel vapor canister heater, maintain open the canister vent valve, open the canister purge valve, maintain closed the vent blocking valve, deactivate the pump, and adjust the VCT system based on engine operating parameters.

14. The system of claim 13, wherein the controller stores further instructions that when executed cause the controller to:

responsive to a fuel tank refill request, deactivate the fuel vapor canister heater, maintain open the canister vent valve, close the canister purge valve, open the vent blocking valve, and deactivate the pump.

15. The system of claim 14, wherein responsive to the indication of wet fouling of the spark plug, the pump is activated to apply pressure to the EVAP system, and wherein the controller stores further instructions that when executed cause the controller to:

responsive to an indication to perform an EVAP system leak test, deactivate the fuel vapor canister heater, open the canister vent valve, close the canister purge valve, open the vent blocking valve, and activate the pump, wherein during at least a portion of the EVAP system leak test, the pump is activated to apply vacuum to the EVAP system; and

after a threshold pressure in the EVAP is reached, close the canister vent valve and indicate a leak in the EVAP system based on a pressure decay of the EVAP system.

16. A method for an engine, comprising:

prior to an engine start, and in response to an indication of spark plug fouling;

adjusting intake and exhaust valves of an engine cylinder to respective open positions by cranking the engine with a starter motor and adjusting a variable cam timing (VCT) system; and

routing a mixture of fuel vapors and fresh air from an evaporative emission control (EVAP) system through the cylinder to an exhaust catalyst.

17. The method of claim 16, wherein routing the mixture of fuel vapors and fresh air from the EVAP system through the cylinder comprises coupling the engine to the EVAP system and applying pressure to the EVAP system.

18. The method of claim 17, wherein coupling the engine to the EVAP system comprises opening a canister purge valve coupling a fuel vapor canister to the engine.

19. The method of claim 18, wherein applying pressure to the EVAP system comprises opening a canister vent valve coupling the fuel vapor canister to atmosphere and activating an EVAP system pump to draw fresh air into the fuel vapor canister and to the engine.