Fuel vapor flow estimation systems and methods

• US 10,190,515 B2
• Filed: 08/30/2016
• Issued: 01/29/2019
• Est. Priority Date: 12/01/2015
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Casetti, Martino, Burleigh, Darrell W.
• Primary Examiner(s): Nguyen, Hung Q
• Assistant Examiner(s): Monahon, Brian P
• Application Number:
  US15/251,806
• Publication Number:
  US 20170152802A1
• Time in Patent Office: 882 Days
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 2200/703 Atmospheric pressure
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/0042 Controlling the combustible mixture as a function of the canister purging, e.g. control of injected fuel to compensate for deviation of air fuel ratio when purging
• CPC Class Codes: F02D 41/0045 Estimating, calculating or determining the purging rate, amount, flow or concentration
• CPC Class Codes: F02D 41/1441 Plural sensors
• CPC Class Codes: F02D 41/1454 the characteristics being an oxygen content or concentration or the air-fuel ratio
• CPC Class Codes: F02D 41/3005 Details not otherwise provided for
• CPC Class Codes: F02D 9/02 concerning induction conduits throttle valves, or arrangements thereof in conduits F02D9/08
• 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 35/1038 for temperature or pressure
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A control system of a vehicle includes a fuel vapor canister that traps fuel vapor from a fuel tank of the vehicle. A purge valve, when open, allows fuel vapor flow into an intake system of an engine at a first location and, when closed, prevents fuel vapor flow to the intake system of the engine. A purge control module controls opening of the purge valve and determines a fuel vapor flow into cylinders of the engine based on: (i) a first pressure at the first location, (ii) a second pressure at a second location between the purge valve and the intake system, and (iii) at least one delay period between opening of the purge valve and fuel vapor reaching cylinders of the engine.

Claims

1. A control system of a vehicle, comprising:

a fuel vapor canister that traps fuel vapor from a fuel tank of the vehicle;

a purge valve that, when open, allows fuel vapor flow into an intake system of an engine at a first location and that, when closed, prevents fuel vapor flow to the intake system of the engine;

a boost device of the intake system is configured to receive air from an air filter and pump air into the engine of the vehicle,

wherein the first location is between the air filter and the boost device;

an electrical pump configured to receive fuel vapor from the fuel vapor canister and to pump fuel vapor to the purge valve; and

a purge control module configured to control opening of the purge valve and to determine a fuel vapor flow into cylinders of the engine based on;

(i) a first pressure at the first location, (ii) a second pressure at a second location between the purge valve and the electrical pump, and (iii) at least one delay period between opening of the purge valve and fuel vapor reaching cylinders of the engine.

2. The control system of claim 1 further comprising:

a first pressure sensor configured to measure the first pressure at the first location between the air filter and the boost device.

3. The control system of claim 1 further comprising a second pressure sensor configured to measure the second pressure at the second location between the electrical pump and the purge valve.

4. The control system of claim 1 wherein, based on the second pressure at the second location, the purge control module is configured to control at least one of (i) opening of the purge valve and (ii) a speed of the electrical pump.

5. The control system of claim 1 wherein the purge control module is configured to:

determine a fuel vapor flow into the intake system at the first location based on the first pressure at the first location, the second pressure at the second location, and a target opening of the purge valve; and

determine the fuel vapor flow into the cylinders as a function of a plurality of values of the fuel vapor flow into the intake system at the first location and the at least one delay period.

6. The control system of claim 5 wherein the purge control module is configured to:

determine a pressure difference across the purge valve based on a difference between the first and second pressures; and

determine the fuel vapor flow into the intake system at the first location based on the pressure difference and the target opening of the purge valve.

7. The control system of claim 1 wherein the at least one delay period includes:

a first delay period between when the purge valve is opened and when the fuel vapor flow into the cylinders will begin to occur; and

a second delay period between when the purge valve is opened and when the fuel vapor flow into the cylinders reaches steady-state, wherein the first delay period is a first predetermined number of combustion events and the second delay period is a second predetermined number of combustion events.

8. A system comprising:

the control system of claim 1; and

a throttle control module configured to selectively adjust opening of a throttle valve of the intake system of the engine based on the fuel vapor flow into the cylinders of the engine and a target air/fuel mixture.

9. A system comprising:

the control system of claim 1; and

a fuel control module configured to control liquid fuel injection for the cylinders of the engine based on the fuel vapor flow into the cylinders of the engine and a target air/fuel mixture.

10. A control method for a vehicle, comprising:

by a fuel vapor canister, trapping fuel vapor from a fuel tank of the vehicle;

selectively opening a purge valve to allow fuel vapor flow into an intake system of an engine at a first location;

selectively closing the purge valve to prevent fuel vapor flow to the intake system of the engine;

by a boost device of the intake system receiving air from an air filter and pumping air into the engine of the vehicle,

wherein the first location is between the air filter and the boost device;

by an electrical pump, receiving fuel vapor from the fuel vapor canister and pumping fuel vapor to the purge valve; and

determining a fuel vapor flow into cylinders of the engine based on;

(i) a first pressure at the first location, (ii) a second pressure at a second location between the purge valve and the electrical pump, and (iii) at least one delay period between opening of the purge valve and fuel vapor reaching cylinders of the engine.

11. The control method of claim 10 further comprising:

measuring the first pressure at the first location using a first pressure sensor at the first location.

12. The control method of claim 10 further comprising measuring the second pressure at the second location using a second pressure sensor at the second location between the electrical pump and the purge valve.

13. The control method of claim 10 further comprising, based on the second pressure at the second location, controlling at least one of (i) opening of the purge valve and (ii) a speed of the electrical pump.

14. The control method of claim 10 further comprising:

determining a fuel vapor flow into the intake system at the first location based on the first pressure at the first location, the second pressure at the second location, and a target opening of the purge valve; and

determining the fuel vapor flow into the cylinders as a function of a plurality of values of the fuel vapor flow into the intake system at the first location and the at least one delay period.

15. The control method of claim 14 further comprising:

determining a pressure difference across the purge valve based on a difference between the first and second pressures; and

determining the fuel vapor flow into the intake system at the first location based on the pressure difference and the target opening of the purge valve.

16. The control method of claim 10 wherein the at least one delay period includes:

a first delay period between when the purge valve is opened and when the fuel vapor flow into the cylinders will begin to occur; and

a second delay period between when the purge valve is opened and when the fuel vapor flow into the cylinders reaches steady-state.

17. The control method of claim 16 wherein the first delay period is a first predetermined number of combustion events and the second delay period is a second predetermined number of combustion events.

18. The control method of claim 10 further comprising selectively adjusting opening of a throttle valve of the intake system of the engine based on the fuel vapor flow into the cylinders of the engine and a target air/fuel mixture.

19. The control method of claim 10 further comprising controlling liquid fuel injection for the cylinders of the engine based on the fuel vapor flow into the cylinders of the engine and a target air/fuel mixture.