EVAPORATIVE EMISSION CONTROL

• US 20140123961A1
• Filed: 11/07/2012
• Published: 05/08/2014
• Est. Priority Date: 11/07/2012
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Kragh, Niels Christopher, Heim, Michael G.
• Granted Patent: US 9,261,057 B2
• Time in Patent Office: Days
• US Class Current: 123/520
• CPC Class Codes: F02D 29/02 peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• 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: F02M 25/0809 Judging failure of purge control system
• 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: F02M 33/04 returning to the intake passage

Abstract

Methods and systems are provided for purging a multi-port canister into an engine intake. Air is circulated through the canister and a resulting purge air is directed to an intake passage upstream of a throttle in engine configured with a throttle body. An amount of fresh intake air received at the intake passage is corresponding decreased.

Claims

1. A method for an engine, comprising:

displacing an amount of unthrottled intake air with air received from a fuel system canister.

2. The method of claim 1, wherein displacing an amount of unthrottled intake air includes displacing an amount of intake air received upstream of an intake throttle.

3. The method of claim 2, wherein each of the intake air and air received from the canister are received at a valve coupled upstream of the throttle.

4. The method of claim 3, wherein the intake air is mixed with the air received from the canister at the valve before entering an engine intake manifold.

5. The method of claim 3, wherein displacing an amount of intake air includes adjusting a position of the valve.

6. The method of claim 3, wherein the amount of intake air displaced is based on one or more of a temperature of the canister, and a hydrocarbon load of the canister.

7. The method of claim 3, the engine is boosted with a turbocharger.

8. The method of claim 1, wherein air received from the fuel system canister includes air entering the canister through each of multiple vents simultaneously, the air purging fuel vapors stored in the canister, and the air exiting the canister through each of multiple purge ports simultaneously.

9. The method of claim 1, wherein the displacing is in response to a canister load being higher than a threshold load.

10. The method of claim 1, wherein each of the unthrottled intake air and the air received from the fuel system canister are substantially at or around barometric pressure.

11. The method of claim 1, wherein the engine operates without an intake throttle, the unthrottled intake air introduced via control of engine intake valve timing, and wherein air from the canister is introduced in the intake manifold between a diverter valve and the engine intake valve.

12. A method for an engine coupled to a fuel system canister, comprising:

during purging conditions, mixing a first amount of intake air with a second, different amount of air received from the canister at a first valve upstream of an intake throttle; and

delivering the mixed air to an engine intake manifold.

13. The method of claim 12, wherein a ratio of the first amount of intake air to the second amount of canister air is varied based on one or more of a temperature of the canister and a hydrocarbon load of the canister.

14. The method of claim 13, wherein the ratio of the first amount of intake air to the second amount of canister air is decreased as the hydrocarbon load of the canister increases.

15. The method of claim 13, wherein the ratio is varied by adjusting a position of the first valve.

16. The method of claim 13, further comprising, after purging the canister, increasing the ratio of the first amount of intake air to the second amount of canister air.

17. The method of claim 12, wherein the second amount of air received from the fuel system canister includes,

opening a second valve coupled to a vent of the canister to receive atmospheric air in the canister through each of multiple canister vent ports simultaneously;

flowing the atmospheric air through the canister to purge stored hydrocarbons; and

opening a third valve coupled between the canister and the first valve to direct the purged hydrocarbons simultaneously through each of multiple canister purge ports, the purged hydrocarbons then directed to the first valve.

18. The method of claim 12, wherein each of the first amount of intake air and the second amount of air received from the canister are substantially at or around atmospheric pressure.

19. A vehicle system, comprising:

an engine including an intake manifold;

an air intake passage for delivering intake air to the intake manifold, the intake passage including a diverter valve;

a fuel tank configured to provide fuel to an engine cylinder;

a multi-port canister coupled to the fuel tank and further coupled to the air intake passage at the diverter valve, the canister configured to store fuel vapors generated in the fuel tank, the canister including a plurality of vent ports coupled to a vent control valve for receiving fresh air in the canister, the canister further including a plurality of purge ports coupled to a purge control valve for delivering purge air from the canister to the diverter valve; and

a controller with computer readable instructions for,

in response to a canister load being higher than a threshold,

opening the purge control valve and the vent control valve;

adjusting a position of the diverter valve to mix purge air from the canister with unthrottled intake air from the intake passage; and

delivering the air mixture to the intake manifold.

20. The system of claim 19, wherein adjusting the position of the diverter valve includes adjusting the position of the diverter valve to reduce an amount of intake air in the air mixture as an amount of purge air received from the canister increases.

21. The system of claim 20, wherein each of the intake air and the purge air received at the diverter valve are substantially at or around atmospheric pressure.

22. The system of claim 20, wherein the controller includes further instructions for, after purging the canister,

closing the vent control valve and the purge control valve;

and

adjusting the position of the diverter valve to increase the amount of intake air delivered to the intake manifold.

23. The system of claim 19, wherein the intake passage includes an intake throttle positioned downstream of the diverter valve, and wherein adjusting a position of the diverter valve to mix purge air from the canister with unthrottled intake air from the intake passage includes mixing purge air from the canister with intake air at the diverter valve, upstream of the throttle.