Evaporative emission system for low engine intake system vacuums

• US 6,196,202 B1
• Filed: 06/30/1998
• Issued: 03/06/2001
• Est. Priority Date: 07/28/1997
• Status: Expired due to Fees

• Current Assignee: Siemens Canada Limited (Siemens AG)
• Original Assignee: Siemens Canada Limited (Siemens AG)
• Inventors: Busato, Murray F., Cook, John Edward
• Primary Examiner(s): MILLER, CARL STUART
• Application Number:
  US09/107,518
• Time in Patent Office: 980 Days
• Field of Search: 123/520, 123/521, 123/519, 123/518, 123/516, 123/533, 123/198.D
• US Class Current: 123/520
• CPC Class Codes: F02M 25/089 Layout of the fuel vapour installation

Abstract

An evaporative emission control system for a fuel system of an internal combustion engine of an automotive vehicle has a purge flow path through which an evaporative emission containment space of the fuel system for containing volatile fuel vapors is purged to an intake system of the engine. A purge valve controls purge flow through the purge flow path. When the intensity of intake system vacuum falls below a threshold, an electric-motor-driven blower operates to creates a pressure rise in the purge flow path upstream of the purge valve and downstream of the containment space. A differential pressure sensor senses pressure differential across the purge valve, and the purge valve includes an integral valve position sensor, both sensors providing feedback signals to a controller than controls operation of both the purge valve and the blower.

Claims

1. An evaporative emission control system for an evaporative emission containment space fuel system of an internal combustion engine of an automotive vehicle, the evaporative emission control system comprising:

a purge flow path through which fuel vapors are purged from the containment space to an intake system of the internal combustion engine;

a purge valve for controlling purge flow through the purge flow path; and

an electric-controlled device that is responsive to pressure differential across the purge valve for augmenting the purge flow controlled by the purge valve;

the device comprising an electric-controlled prime mover that is selectively operable to a pressure-creating condition for augmenting the purge flow through the purge valve and to a non-pressure-creating condition that allows bi-directional flow through the purge flow path;

the electric-controlled prime mover comprising an electric-motor-driven blower disposed in the purge flow path between the evaporative emission containment space and the purge valve; and

a differential pressure sensor having an input for sensing pressure differential across the purge valve, as measured between an inlet port at which purge flow enters the purge valve and an outlet port at which purge flow exits the purge valve and to which intake system vacuum is communicated, and an output for providing a corresponding electric signal to an electric circuit that controls the device and that is responsive to change in the electric signal caused by decrease in intake system vacuum to cause the device to augment the purge flow to compensate for the decrease in intake system vacuum.

2. An evaporative emission control system for an evaporative emission containment space of a fuel system of an internal combustion engine of an automotive vehicle, the evaporative emission control system comprising:

a purge flow path through which fuel vapors are purged from the containment space to an intake system of the internal combustion engine;

a purge valve for controlling purge flow through the purge flow path; and

an electric-controlled device that is responsive to pressure differential across the purge valve for augmenting the purge flow controlled by the purge valve; and

a differential pressure sensor having an input for sensing pressure differential across the purge valve, as measured between an inlet port at which purge flow enters the purge valve and an outlet port at which purge flow exits the purge valve and to which intake system vacuum is communicated, and an output for providing a corresponding electric signal to an electric controller that controls the device and that is responsive to change in the electric signal caused by decrease in intake system vacuum to cause the device to augment the purge flow to compensate for the decrease in intake system vacuum.

3. An evaporative emission control system for an evaporative emission containment space of a fuel system of an internal combustion engine of an automotive vehicle, the evaporative emission control system comprising:

a purge flow path through which fuel vapors are purged from the containment space to an intake system of the internal combustion engine;

a purge valve for controlling purge flow through the purge flow path, the purge valve having an inlet port at which the purge flow enters the purge valve and an outlet port at which purge flow exits the purge valve and to which intake system vacuum is communicated; and

an electric-controlled device that is responsive to pressure differential across the purge valve for augmenting the purge flow controlled by the purge valve;

an electric controller for processing input data to control operation of both the device and the purge valve;

the purge valve comprising an electric actuator that is controlled by the controller to operate a purge valve mechanism of the purge valve for controlling purge flow, and the device comprising an electric-controlled prime mover that is controlled by the controller; and

including a sensor providing a feedback signal to the controller indicative of actual pressure differential across the purge valve mechanism;

the electric controller being responsive to change in the feedback signal caused by decrease in intake, system vacuum to cause the electric-controlled prime mover to augment the purge flow to compensate for the decrease in intake system vacuum.

4. An evaporative emission control system as set forth in claim 3 in which the purge valve includes a sensor providing a feedback signal to the controller indicative of actual operation of the purge valve mechanism.

5. An automotive vehicle comprising:

an internal combustion engine for powering the vehicle;

a fuel system comprising a tank for holding a supply of volatile fuel for the engine and a containment space for containing fuel vapors; and

an evaporative emission control system for containing and disposing of fuel vapors resulting from the volatilization of fuel in the tank, the evaporative emission control system comprising;

a purge flow path through which contained fuel vapors are purged to the engine for disposal;

a purge valve for controlling purge flow through the purge flow path, an electric-controlled device that is responsive to a condition associated with purging of the containment space to the engine through the purge valve for augmenting the purge flow controlled by the purge valve;

an electric controller for controlling operation of the purge valve and of the device by respective control signals; and

including a first sensor providing a feedback signal to the controller indicative of actual operation of the purge valve and a second sensor providing a feedback signal to the controller indicative of actual pressure differential across the purge valve, as measured between an inlet port at which purge flow enters the purge valve and an outlet port at which purge flow exits the purge valve and to which intake system vacuum is communicated; and

the electric controller being responsive to change in the feedback signal from the second sensor caused by decrease in intake system vacuum to cause the electric-controlled device to augment the purge flow to compensate for the decrease in intake system vacuum.