Automotive evaporative emission leak detection system and module
First Claim
1. An automotive vehicle comprising:
- a fuel-consuming internal combustion engine that powers the vehicle and comprises an intake manifold;
a fuel storage system for storing volatile liquid fuel for consumption by the engine and comprising an evaporative emission space for containing fuel vapor;
an evaporative emission control system comprising a vent valve for selectively opening and closing a vent path from the evaporative emission space to atmosphere, a fuel vapor collection medium disposed in the vent path for trapping fuel vapors so their escape to atmosphere through the vent path is prevented, and a purge valve for selectively opening and closing a vapor purge path from the evaporative emission space to the intake manifold to selectively purge fuel vapors from the evaporative emission space and medium to the engine; and
a vacuum regulator valve for regulating vacuum in the evaporative emission space to a defined magnitude when the vent valve is closed, the purge valve is open, and the engine is running.
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Accused Products
Abstract
A module for an on-board evaporative emission leak detection system that detects leakage from an evaporative emission space of a fuel system of an automotive vehicle. The module has a housing that includes a first port for communicating the housing to the evaporative emission space and a second port for communicating the housing to atmosphere. The housing contains a particulate filter through which the second port communicates with two parallel flow branches that extend within the housing to the first port. One branch contains a vacuum regulator valve, and the other, a solenoid-operated vent valve. During a leak detection test, the vent valve is operated closed, and a purge valve, that selectively communicates the evaporative emission space with the engine intake manifold, is operated open to cause vacuum to be drawn in the evaporative emission space. The vacuum regulator valve regulates evaporative emission space vacuum to a defined vacuum. Subsequently, the purge valve is operated closed. Leakage is evidenced by loss of vacuum, and a pressure sensor signals vacuum loss.
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Citations
21 Claims
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1. An automotive vehicle comprising:
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a fuel-consuming internal combustion engine that powers the vehicle and comprises an intake manifold; a fuel storage system for storing volatile liquid fuel for consumption by the engine and comprising an evaporative emission space for containing fuel vapor; an evaporative emission control system comprising a vent valve for selectively opening and closing a vent path from the evaporative emission space to atmosphere, a fuel vapor collection medium disposed in the vent path for trapping fuel vapors so their escape to atmosphere through the vent path is prevented, and a purge valve for selectively opening and closing a vapor purge path from the evaporative emission space to the intake manifold to selectively purge fuel vapors from the evaporative emission space and medium to the engine; and a vacuum regulator valve for regulating vacuum in the evaporative emission space to a defined magnitude when the vent valve is closed, the purge valve is open, and the engine is running. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An on-board evaporative emission leak detection system for detecting leakage from an evaporative emission space of a fuel storage system for storing volatile liquid fuel for consumption by an engine of an automotive vehicle, the leak detection system comprising:
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two parallel flow branches between the evaporative emission space and atmosphere; one branch comprising a selectively operable vent valve for opening and closing the one branch; and the other branch comprising a regulator valve for regulating pressure differential between atmosphere and the evaporative emission space to a defined differential when the vent valve is closed and the differential attempts to increase beyond the defined differential. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14)
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15. A module for an on-board evaporative emission leak detection system for detecting leakage from an evaporative emission space of a fuel storage system that stores volatile liquid fuel for consumption by an engine of an automotive vehicle, the module comprising:
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a housing having a first port adapted to be placed in communication with the evaporative emission space and a second port adapted to be communicated to atmosphere; two parallel flow branches between the first and second ports; one branch comprising a selectively operable vent valve for opening and closing the one branch; and the other branch comprising a regulator valve for regulating pressure differential between the first and second ports to a defined differential when the vent valve is closed and the differential attempts to increase beyond the defined differential. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A module for an on-board evaporative emission leak detection system for detecting leakage from an evaporative emission space of a fuel storage system for storing volatile liquid fuel for consumption by an engine of an automotive vehicle, the module comprising:
a housing comprising a movable wall dividing a first chamber from a second chamber, an atmospheric port for communicating the first chamber to atmosphere, an emission space port for communicating the second chamber to an evaporative emission space, a valve comprising relatively positionable first and second parts, the first part being movable with the movable wall relative to the second part to open and close a flow path through the movable wall between the first and second chambers, a spring biasing the two parts toward closure of the flow path, and the spring and the two chambers having a relationship that causes the flow path to be closed when pressure differential between the two chamber spaces is less than a predetermined differential, and that causes the flow path to be open when the pressure differential between the two chamber spaces is greater than the predetermined differential.
Specification