Systems and methods for opportunistic vehicle evaporative emissions test diagnostic

Patent metadata

Field	Value
Publication number	US-9828951-B2
Application number	US-201615092336-A
Country	US
Kind code	B2
Filing date	Apr 6, 2016
Priority date	Apr 6, 2016
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

Methods and systems are provided for opportunistically conducting an evaporative emissions test diagnostic procedure in order to indicate the presence or absence of undesired evaporative emissions in a vehicle evaporative emissions control system and fuel system. In one example, tire pressure and barometric pressure are monitored, and responsive to a tire pressure decrease in the absence of a barometric pressure increase, along with an indication that the vehicle transmission is in neutral and that the vehicle is not traveling downhill, the evaporative emissions system and fuel system may be sealed and the presence or absence of undesired evaporative emissions indicated based on a vacuum-build. In this way, an opportunistic evaporative emissions test may be conducted based on conditions favorable to conducting an emissions test procedure, and may thus increase test completion rates and reduce undesired evaporative emissions.

First claim

The invention claimed is:

1. A method comprising:
responsive to an indication that a vehicle is in the process of a car wash event;
sealing a fuel system which supplies fuel to an engine propelling the vehicle and an evaporative emissions system coupled to the fuel system; and
conducting a diagnostic test for the presence of undesired evaporative emissions.

2. The method of claim 1 , further comprising:
monitoring pressure in one or more tires of the vehicle; and wherein
indicating that the vehicle is in the process of a car wash event includes indicating a tire pressure decrease greater than a predetermined threshold.

3. The method of claim 1 , further comprising;
monitoring barometric pressure via a barometric pressure sensor positioned in an intake manifold of the engine; and wherein
indicating that the vehicle is in the process of a car wash event includes an absence of change in barometric pressure.

4. The method of claim 3 , further comprising:
controlling an intake air amount inducted into the engine intake manifold via a throttle; and
wherein
an absence of change in barometric pressure includes indicating that a throttle position is below a throttle position threshold.

5. The method of claim 1 , further comprising:
monitoring vehicle pitch angle via one or more lateral sensors in the vehicle; and wherein indicating that the vehicle is in the process of a car wash event includes indicating that the vehicle pitch angle is less than a threshold pitch angle.

6. The method of claim 1 , wherein indicating that the vehicle is in the process of a car wash event includes indicating that a transmission of the vehicle is in a neutral gear state.

7. The method of claim 1 , wherein the fuel system includes a fuel tank that supplies fuel to the engine, and the evaporative emissions system includes a fuel vapor canister configured to capture and store fuel vapors from the fuel tank; and wherein
sealing the fuel system and evaporative emissions system comprises sealing the fuel system and evaporative emission system from atmosphere and from the engine; and wherein
a fuel tank temperature decrease during the car wash event results in a vacuum build in the fuel system and evaporative emissions system.

8. The method of claim 7 , wherein conducting the diagnostic test for the presence of undesired evaporative emissions includes indicating an absence of undesired evaporative emissions responsive to a vacuum build in the fuel system and evaporative emissions system greater than a predetermine vacuum threshold, or a rate of vacuum build greater than a predetermined threshold vacuum build rate.

9. The method of claim 1 , wherein indicating that the vehicle is in the process of a car wash event further comprises:
indicating the car wash event based on one or more of a vehicle global positioning system (GPS) and onboard camera(s).

10. A system for a vehicle, comprising:
an engine;
a fuel tank, configured within a fuel system which supplies fuel to the engine;
a fuel vapor canister, configured within an evaporative emissions control system, fluidically coupled to an engine intake manifold via a canister purge valve, fluidically coupled to atmosphere via a canister vent valve; and fluidically coupled to the fuel tank;
a barometric pressure sensor in the engine intake manifold;
one or more tire pressure sensors coupled to one or more tires of the vehicle;
a controller storing instructions in non-transitory memory, that when executed, cause the controller to:
monitor tire pressure in the one or more vehicle tires;
monitor barometric pressure via the barometric pressure sensor; and
responsive to an indication of a tire pressure decrease greater than a predetermined threshold and an absence of barometric pressure change:
in a first condition, seal the evaporative emissions system and fuel system from atmosphere and from the engine intake manifold by commanding closed the canister vent valve and canister purge valve without conducting an evaporative emissions test diagnostic on the fuel system and evaporative emissions system; and
in a second condition, seal the evaporative emissions system and fuel system from atmosphere and from the engine intake manifold by commanding closed the canister vent valve and canister purge valve and conduct an evaporative emissions test diagnostic on the fuel system and evaporative emissions system.

11. The system of claim 10 , further comprising:
an intake throttle coupled to the engine intake manifold;
one or more lateral sensors; and wherein
the controller further stores instructions in non-transitory memory, that when executed, cause the controller to:
control an intake air amount inducted into the engine intake manifold via the throttle;
monitor vehicle pitch angle via the one or more lateral sensors in the vehicle, wherein a vehicle pitch angle greater than a threshold pitch angle indicates the vehicle is traveling downhill; and
wherein the first condition includes a throttle position greater than a throttle position threshold, or the throttle position less than the throttle position threshold, the vehicle pitch angle less than the threshold pitch angle, and an indication that the vehicle is not in a neutral transmission gear state;
wherein the second condition includes the throttle position less than the throttle position threshold, the vehicle pitch angle less than the threshold pitch angle, and an indication that the vehicle is in a neutral transmission gear state; and wherein
the throttle position greater than the throttle position threshold indicates accurate barometric pressure readings as monitored by the barometric pressure sensor.

12. The system of claim 11 , wherein the controller further stores instructions in non-transitory memory, that when executed, cause the controller to:
responsive to an indication of tire pressure decrease greater than the predetermined threshold and a corresponding barometric pressure change:
adjust engine operating parameters based on barometric pressure change; and

responsive to an indication of tire pressure decrease greater than the predetermined threshold, the absence of barometric pressure change, the throttle position less than the throttle position threshold, and the vehicle pitch angle greater than the threshold pitch angle:
adjust engine operating parameters based on tire pressure change.

13. The system of claim 10 , wherein the controller further stores instructions in non-transitory memory, that when executed, cause the controller to:
during the first condition, monitor tire pressure in the one or more vehicle tires; and
responsive to a tire pressure increase greater than a predetermined threshold:
unseal the evaporative emissions system and fuel system from atmosphere by commanding open the canister vent valve.

14. The system of claim 10 , further comprising:
a fuel tank pressure transducer; and wherein
the controller further stores instructions in non-transitory memory, that when executed, cause the controller to:
during the second condition, monitor pressure in the fuel system and evaporative emissions system; and
indicate an absence of undesired evaporative emissions responsive to vacuum in the fuel system and evaporative emissions system reaching a threshold vacuum, or responsive to a rate of vacuum build in the fuel system and evaporative emissions system greater than a predetermined threshold vacuum build rate.

15. The system of claim 14 , wherein the controller further stores instructions in non-transitory memory, that when executed, cause the controller to:
adjust the threshold

Assignees

• Ford Global Tech Llc

Inventors

• Dudar Aed M

Classifications

• F02D2200/50

  said parameters being related to the vehicle or its components · CPC title

• F02D2200/502

  Neutral gear position · CPC title

• F02D41/22

  Safety or indicating devices for abnormal conditions {(in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809)} · CPC title

• F02D41/0032

  Controlling the purging of the canister as a function of the engine operating conditions · CPC title

• F02D9/02

  concerning induction conduits (throttle valves, or arrangements thereof in conduits F02D9/08) · CPC title