Automotive evaporative leak detection system
AssigneeSiemens Canada Limited
InventorsJohn E. Cook, Paul D. Perry
Life of this patent
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Abstract
A leak detection monitor (22; 222) 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. One embodiment (22) utilizes engine intake system vacuum to vent the evaporative emission space to atmosphere when the engine is running; another (222), an electromagnet actuator (270, 280). Venting ceases when the engine is shut off. Changes in vapor pressure in the evaporative emission space are monitored over time by electric devices (74; 282) after the engine has been shut off to distinguish between a gross leak, a small leak smaller than a gross leak, and a leak that is at most smaller than a small leak.
Claims73
A leak detection monitor for an on-board evaporative emission leak detection system that detects leakage from an evaporative emission space of a fuel system for an engine of an automotive vehicle, the leak detection monitor comprising:
- a housing extending along a longitudinal axis and defining an interior volume;
- a separation member disposed within the housing and dividing the interior volume into a first housing chamber and a second housing chamber;
- a first port disposed through the housing and in communication with the first housing chamber, the first port adapted to communicate with a manifold;
- a second port disposed though the housing and in communication with the second housing chamber, the second port adapted to communicate with the evaporative emission space;
- a third port disposed through the housing and in communication with the second housing chamber, the third port adapted to communicate with atmosphere;
- a metering member disposed in the interior volume, the metering member positionable in a closed position prohibiting flow between the second and third ports and an open position to permitting flow therebetween;
- a pressure sensor disposed in the interior volume, the pressure sensor adapted to measure relative pressures between the second and third ports and to output an electrical signal in response to the relative pressures;
- and
- an actuating member adapted to position the metering member in the open position when the engine is being operated and in the closed position when the engine is not being operated.
A method of diagnosing an evaporative emission control system to determine if a leak is present in the system, the method comprising:
- sealing the system from external influences;
- monitoring a pressure level within the system over a cooling period;
- and
- indicating a potential leak condition through a comparison of the pressure level within the system and a given threshold.
A method of diagnosing an evaporative emission control system to determine if a leak is present in the system, the method comprising:
- sealing the system from external influences;
- and
- monitoring a first pressure level at a first port in communication with atmosphere of an integrated housing and a second pressure level at a second port in communication with an evaporative emission space, the first and second ports disposed within a unitary housing.
An on-board evaporative emission leak detection system for detecting leakage from an evaporative emission space of a fuel system for an engine of an automobile, comprising:
- a canister in communication with the evaporative emission space;
- a filter in communication with atmosphere;
- and
- a monitor adapted to measure the leakage, the monitor comprising:
- a housing extending along a longitudinal axis and defining an interior volume;
- a first port disposed through the housing and in communication with a first portion of the interior volume and the canister;
- a second port disposed through the housing and in communication with a second portion of the interior volume and the filter;
- and
- a metering member disposed in interior volume and defining the first portion with the first port and the second portion with the second port, the metering member positionable in a closed position prohibiting flow between the ports and an open position permitting flow between the ports.
Dependencies are inferred from the claim text.