Checking Functionality of Fuel Tank Vapor Pressure Sensor

• US 20110197862A1
• Filed: 02/18/2010
• Published: 08/18/2011
• Est. Priority Date: 02/18/2010
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: McCarthy, Timothy E., Der Manuelian, Raffi, Kalvelage, Kenneth J.
• Granted Patent: US 8,342,157 B2
• Time in Patent Office: Days
• US Class Current: 123/521
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system

Abstract

A vehicle fuel emissions system includes a fuel tank, a tank pressure sensor indicating a pressure differential between the tank and a port communicating with the atmosphere, a pump for selectively producing vacuum in the tank, and a passage connecting the pump and a pressure sensor air reference port external to the system.

Claims

1. A vehicle fuel emissions system, comprising:

a fuel tank;

a tank pressure sensor indicating a pressure differential between the tank and a port communicating with the atmosphere;

a pump for selectively producing vacuum in the tank; and

a passage connecting the pump and the pressure sensor external to the system.

2. The system of claim 1, further comprising:

a carbon canister communicating with the tank, the tank pressure sensor and the port communicating with the tank through the canister.

3. The system of claim 1, further comprising a normally-closed diurnal control valve for opening and closing communication between the system and atmospheric pressure external to the system.

4. The system of claim 1, further comprising:

a carbon canister communicating with the tank; and

a normally-closed diurnal control valve connected to the pump and the canister, the passage bypassing the diurnal control valve.

5. The system of claim 1, further comprising:

a second pressure sensor indicating a magnitude of vacuum produced by the pump between the port and the pump.

6. A vehicle fuel emissions system, comprising:

a fuel tank;

a tank pressure sensor indicating a pressure differential between the tank and a port communicating with the atmosphere;

a first vapor flow path connecting the tank and the tank pressure sensor;

a pump for selectively producing vacuum in the tank;

a second vapor flow path connecting the tank and the pump; and

a passage connecting the pump and a vapor pressure sensor air reference port external to the system.

7. The system of claim 6, further comprising:

a carbon canister located in the first vapor flow path and communicating with the tank, the tank pressure sensor and the port communicating with the tank and the canister through the first vapor flow path.

8. The system of claim 6, further comprising a normally-closed diurnal control valve for opening and closing communication between the system and atmospheric pressure external to the system.

9. The system of claim 6, further comprising:

a carbon canister located in the first vapor flow path and communicating with the tank; and

a normally-closed diurnal control valve connected to the pump and the canister, the passage bypassing the diurnal control valve.

10. The system of claim 6, further comprising:

a second pressure sensor indicating a magnitude of vacuum produced by the pump between the port and the pump.

11. The system of claim 10 wherein the second pressure sensor indicates absolute pressure.

12. A method for checking operation of a sealed fuel emissions system for a vehicle, comprising the steps of:

(a) using a fuel tank pressure sensor that indicates a magnitude of pressure in the fuel tank;

(b) using a pump to produce vacuum in the system;

(c) communicating said vacuum to a port communicating with a reference port of a fuel tank vapor pressure sensor; and

(d) checking correct operation of the fuel tank pressure sensor by comparing a pressure change indicated by the fuel tank vapor pressure sensor due to said vacuum with a pressure change due to said vacuum indicated by the fuel tank pressure sensor.

13. The method of claim 12 wherein the system remains sealed while performing the method by maintaining closed a purge valve and a closed diurnal control valve arranged in parallel with the purge valve, which open and close communication between the system and atmosphere external to the system.