Method and system for detecting PHEV EVAP system recirculation tube reliability

Patent metadata

Field	Value
Publication number	US-9410507-B2
Application number	US-201314034490-A
Country	US
Kind code	B2
Filing date	Sep 23, 2013
Priority date	Sep 23, 2013
Publication date	Aug 9, 2016
Grant date	Aug 9, 2016

Abstract

A method for detecting blockage within a recirculation tube of the evaporative emission control system of a PHEV measures the rise in interior temperature of a canister of the EVAP system, during the process of refueling, and notes an initial state of loading of the canister before refueling, indicative of the amount of hydrocarbons contained within the canister It is inferred that the recirculation tube is operative reliably if the rise in canister temperature is below a pre-determined temperature value.

First claim

What is claimed is:

1. A method for verifying reliable operation of a recirculation tube of an evaporative emission control system of a plug-in hybrid electric vehicle, the recirculation tube having a first end connected to a fuel-filler neck of the vehicle fuel system, and a second end connected to a canister of the evaporative emission control system, the method comprising:
detecting refueling, employing a fuel level sensor, and inputting to a controller a signal corresponding to the change in fuel level during refueling;
measuring canister temperature at least before, and after refueling, employing a temperature sensor, inputting signals corresponding to the measured canister temperature to the controller, and storing the temperature signals;
determining whether the recirculation tube is blocked, employing the controller, including
processing the stored temperature signals to determine an actual refueling temperature differential;
processing the fuel level signals, together with pre-calculated fuel-related data to determine an anticipated refueling temperature differential;
comparing the actual refueling temperature differential with the anticipated refueling temperature differential to calculate the mismatch between those values, and
in the event that the mismatch exceeds a predetermined value, outputting a signal to the evaporative emission control system indicating that the recirculation tube is blocked.

2. The method of claim 1 , wherein the pre-determined temperature value is based on one or more of:
the initial loading state of the canister;
the type and the amount of fuel filled within the fuel tank during refueling; or
the initial canister temperature, before refueling.

3. The method of claim 1 , further comprising, positioning multiple temperature sensors at different locations within the canister, to measure the rise in canister temperature during refueling.

Assignees

• Ford Global Tech Llc
• Ford Global Techniologies Llc

Inventors

• Pearce Russell Randall
• Yang Dennis Seung-Man
• Dudar Aed M

Classifications

• F02M25/0809 Primary

  Judging failure of purge control system · CPC title

• F02M25/0872

  Details of the fuel vapour pipes or conduits · CPC title

• F02M25/0854

  Details of the absorption canister · CPC title