Canister vent valve having electric pressure sensor and valve actuator

• US 5,803,056 A
• Filed: 02/12/1997
• Issued: 09/08/1998
• Est. Priority Date: 02/12/1997
• Status: Expired due to Term

• Current Assignee: Siemens Electric Limited
• Original Assignee: Siemens Electric Limited
• Inventors: Cook, John E., Perry, Paul D., Weldon, Craig A.
• Primary Examiner(s): MILLER, CARL STUART
• Application Number:
  US08/798,818
• Time in Patent Office: 573 Days
• Field of Search: 123/519, 123/520, 123/518, 123/516, 123/521, 123/198 D, 123/458, 123/506, 123/494, 137/487.5, 251/129.04
• US Class Current: 123/520
• CPC Class Codes: F02B 23/104 the injector being placed on a side position of the cylinder
• CPC Class Codes: F02M 25/0836 Arrangement of valves controlling the admission of fuel vapour to an engine, e.g. valve being disposed between fuel tank or absorption canister and intake manifold
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y10T 137/7761 Electrically actuated valve

Abstract

A vapor collection canister vent valve contains both an electric pressure sensor for measuring evaporative emission space pressure during a diagnostic test and an electric actuator for operating the vent valve closed during a diagnostic test. Use of the valve in an evaporative emission control system reduces the number of connections, both electrical and fluid, that are required to install the valve in a system. The remote location of the pressure sensor damps the effect of pressure transients, such as those due to tank fuel slosh, on the sensor.

Claims

1. In a vapor collection system for an internal combustion engine fuel system wherein a canister purge valve is disposed between an intake manifold of an engine and a fuel vapor collection canister that collects vapor generated by volatile fuel in a fuel tank, and the purge valve both a) controls the purging of said canister to said intake manifold in accordance with a purge control signal that sets the extent to which said canister purge valve allows purge flow and b) in response to a leak detection test signal closes the canister to the intake manifold for testing the integrity against leakage of evaporative emission space cooperatively defined by the canister and headspace of the fuel tank, and a vent valve is disposed between a vent port of the canister for venting the evaporative emission space through the canister, the improvement in which said vent valve comprises a walled housing defining an enclosed interior space and comprising a first port and a second port for communicating with the interior space, a valve operated by an electric actuator disposed within the interior space for selectively allowing and disallowing communication between said ports through said interior space, a device for providing an electric signal related to pressure in said interior space, and electric terminals connected to said electric actuator and said device to provide for said actuator and device to be connected in an electric circuit for the vapor collection system.

2. The improvement set fort in claim 1 wherein the device comprises an electric pressure sensor providing an electric signal measurement of pressure in said interior space relative to a reference pressure.

3. The improvement as set forth in claim 2 in which the sensor is disposed within said interior space.

4. The improvement as set forth in claim 2 in which said sensor comprises a reference pressure sensing zone and a measured pressure sensing zone, said reference pressure sensing zone being disposed against a wall of the housing and communicated to atmosphere through a hole in that wall, and the measured pressure sensing zone being open to the interior space.

5. The improvement as set forth in claim 2 in which the sensor is a vacuum sensor for measuring vacuum in said interior space.

6. A vent valve for disposition between a vent port of a vapor collection canister of a vapor collection system to vent the evaporative emission space through the canister, said vent valve comprising a walled housing defining an enclosed interior space and comprising a first port and a second port for communicating with the interior space, a valve operated by an electric actuator disposed within the interior space for selectively allowing and disallowing communication between said ports through said interior space, a device for providing an electric signal related to pressure in said interior space, and electric terminals connected to said electric actuator and said pressure device to provide for said actuator and device to be connected in an electric circuit for the vapor collection system.

7. A vent valve as set forth in claim 6 wherein the device comprises an electric pressure sensor providing an electric signal measurement of pressure in said interior space relative to a reference pressure.

8. A vent valve as set forth in claim 7 in which the sensor is disposed within said interior space.

9. A vent valve as set forth in claim 7 in which said sensor comprises a reference pressure sensing zone and a measured pressure sensing zone, said reference pressure sensing zone being disposed against a wall of the housing and communicated to atmosphere through a hole in that wall, and the measured pressure sensing zone being open to the interior space.

10. A vent valve as set forth in claim 7 in which the sensor is a vacuum sensor for measuring vacuum in said interior space.