Abstract: An on-board diagnostic system for an evaporative emission control system of an internal combustion engine powered vehicle employs a positive displacement reciprocating pump to create in evaporative emission space a pressure that differs significantly from ambient atmospheric pressure. The pump is powered by using engine intake manifold vacuum to force an intake stroke during which both an internal spring is increasingly compressed and a charge of ambient atmospheric air is created in an air pumping chamber space. Vacuum is then removed, and the spring relaxes to force a compression stroke wherein a portion of the air charge is forced into the evaporative emission space. The rate at which the pump reciprocates to alternately execute intake and compression strokes indicates the pressure and flow through a leak in the evaporative emission space. Detection of this rate serves as a measurement of leakage for the purpose of distinguishing integrity of the evaporative emission space from non-integrity.

Abstract: The evaporative emission control system for an internal combustion engine purges the vapor collection canister to the intake manifold through a purge regulator controlled by the engine ECU. The purge regulator comprises a diaphragm valve and an electronic vacuum regulator. The purge regulator functions to allow a purge flow rate correlated with a control signal from the engine ECU and manifold vacuum, to maintain the purge flow rate substantially constant in response to certain changes in the magnitude of manifold vacuum, and to re-adjust the purge flow rate in correlation with changes in the control signal from the engine ECU. The diaphragm valve comprises a tapered valve element that progressively reduces the flow restriction as the valve element is increasingly opened.

Abstract: A method of forming a composite extrusion is disclosed wherein a main body portion (1) of the extrusion is first extruded from a thermosetting material, this body portion then being heated so as at least partly to cure it, the main body portion then being passed at high temperature through a further extruder where a thermoplastics material (8) is extruded onto one or more surfaces of the main body portion (1), the subsequent composite extrusion then being cooled and formed into its final shape.

Abstract: The valve has a one-piece guide and valve seat member and a one-piece valve member that is guided by a bushing lining the guide of the guide and seat member. The valve is operated by a duty-cycle modulated waveform, and when the valve is operated in the closing direction, a gap is introduced into the waveform. The valve head and valve seat are configured to cause sonic flow through the valve when the valve is open and the pressure differential across it exceeds a certain minimum.

Abstract: A method of forming a composite extrusion is disclosed wherein a main body portion (1) of the extrusion is first extruded from a thermosetting material, this body portion then being heated so as at least partly to cure it, the main body portion then being passed at high temperature through a further extruder where a thermoplastics material (8) is extruded onto one or more surfaces of the main body portion (1), the subsequent composite extrusion then being cooled and formed into its final shape.

Abstract: The tank/canister volume's integrity against unacceptable leakage measured by a diagnostic test performed by an on-board diagnostic system which includes an electrically operated air pump and tank-mounted analog pressure transducer. At the beginning of a test, the engine management computer closes the canister purge solenoid valve and operates the pump to begin pressurization of the tank/canister volume. The pumped air is introduced via the canister's atmospheric vent port at a regulated pressure. Failure to build tank pressure to a predetermined pressure within a predetermined time indicates a gross leak. If no gross leak exists, the pressure will build, and the time required to build to a given pressure from the start pressure provides a measurement of any leakage that may be present. The fuel fill level in the tank affects this time, and it is taken into account in the measurement.

Abstract: The valve shaft passes through a journal bearing in the wall of the valve body to an actuating lever attached to the shaft on the outside of the valve body. This journal bearing is sealed by an arrangement of several parts to prevent escape of exhaust gases. These parts include a bellows and ceramic thrust washers. By making the valve shaft axis non-perpendicularly intersecting the axis of the valve body wall, the entire circumference of the valve blade can be sealed to the valve body wall when the valve is closed.

Abstract: Leakage from a portion of a canister purge system which includes a fuel tank and a vapor collection canister is detected by closing off that portion and then positively pressurizing it by means of an air pump. The air that is pumped by the air pump is split into two separate paths, one to pressurize the closed-off portion of the system, and the other to flow through a known orifice. A differential flow meter compares the flow through one path with that through the other to determine if there is leakage.

Abstract: An on-board diagnostic system for an evaporative emission control system of an internal combustion engine powered vehicle employs a positive displacement reciprocating pump to create in evaporative emission space a pressure that differs significantly from ambient atmospheric pressure. The pump is powered by using engine intake manifold vacuum to force an intake stroke during which both an internal spring is increasingly compressed and a charge of ambient atmospheric air is created in an air pumping chamber space. Vacuum is then removed, and the spring relaxes to force a compression stroke wherein a portion of the air charge is forced into the evaporative emission space. The rate at which the pump reciprocates to alternately execute intake and compression strokes indicates the pressure and flow through a leak in the evaporative emission space. Detection of this rate serves as a measurement of leakage for the purpose of distinguishing integrity of the evaporative emission space from non-integrity.

Abstract: The tank/canister volume's integrity against unacceptable leakage is either confirmed or denied by a diagnostic test performed by an on-board diagnostic system which includes an electrically operated air pump and tank-mounted analog pressure transducer. At the beginning of a test, the engine management computer closes the canister purge solenoid valve and operates the pump to begin pressurization of the tank/canister volume. The pumped air is introduced via the canister's atmospheric vent port so that the pressurizing air is entrained with fuel vapors previously collected in, but not yet purged from, the canister. Failure to build to a predetermined pressure within a predetermined time indicates a gross leak. Upon attainment of the predetermined pressure, the pump is shut off. If the pressure drops by more than a certain amount during the test, integrity is denied. If not, integrity is confirmed.

Abstract: An evaporative emission control system for an automotive vehicle comprises an integrated roll-over valve and vapor pressure sensor assembly mounted by means of a grommet in the top wall of the vehicle's fuel tank. The vapor pressure sensor forms part of an on-board diagnostic system for testing the integrity of the tank and vapor collection canister against leaks.

Abstract: The evaporative emission control system for an internal combustion engine purges the vapor collection canister to the intake manifold through a purge regulator controlled by the engine ECU. The purge regulator comprises a diaphragm valve and an electronic vacuum regulator. The purge regulator functions to allow a purge flow rate correlated with a control signal from the engine ECU and manifold vacuum, to maintain the purge flow rate substantially constant in response to certain changes in the magnitude of manifold vacuum, and to re-adjust the purge flow rate in correlation with changes in the control signal from the engine ECU. The diaphragm valve comprises a tapered valve element that progressively reduces the flow restriction as the valve element is increasingly opened.

Abstract: The evaporative emission control system for an internal combustion engine purges the vapor collection canister to the intake manifold through a purge regulator controlled by the engine ECU. The purge regulator comprises a diaphragm valve and an electronic vacuum regulator. The purge regulator functions to allow a purge flow rate correlated with a control signal from the engine ECU and manifold vacuum, to maintain the purge flow rate substantially constant in response to certain changes in the magnitude of manifold vacuum, and to re-adjust the purge flow rate in correlation with changes in the control signal from the engine ECU. The diaphragm valve comprises a tapered valve element that progressively reduces the flow restriction as the valve element is increasingly opened.

Abstract: An on-board diagnostic system determines if there is a leak in the portion of a canister purge system that includes the fuel tank and the canister that collects volatile fuel vapors from the fuel tank's headspace. A vacuum regulator/sensor placed in the conduit between the CPS valve and the canister, includes a switch providing a signal indicating the presence or absence of a leak. The sensor also indicates both positive and negative pressures relative to a reference pressure such as atmosphere. During diagnostic testing, the switch is closed and if the switch becomes open this indicates a leak in the headspace of fuel tank on the canister.

Abstract: A vacuum boost valve senses when the intensity of vacuum from a variable intensity vacuum source is about to drop below a threshold and supplies a boost so that when the intensity of the vacuum source is within a range immediately below the threshold, the intensity of vacuum delivered to a load does not drop below the intensity of the vacuum source and is in fact increased over what it would otherwise be without the boost. The vacuum boost is obtained by using a venturi.

Abstract: A multi-slope canister purge solenoid (CPS) valve has a diaphragm-controlled valve downstream of the solenoid-actuated valve. The diaphragm-controlled valve has two diaphragms that between themselves define a chamber space that is communicated to intake manifold vacuum. One of the two diaphragms is exposed to atmospheric pressure while the other is exposed to the interior of the CPS valve.

Abstract: The tank/canister volume's integrity against unacceptable leakage is either confirmed or denied by a diagnostic test performed by an on-board diagnostic system which includes an electrically operated air pump and a pressure switch. At the beginning of a test, the engine management computer closes the canister purge solenoid valve and operates the pump to begin pressurization of the tank/canister volume. Failure to build to a predetermined pressure indicates a gross leak. Upon attainment of the predetermined pressure, the pump is shut off by the operation of the pressure switch from one state to another. The pressure switch has hysteresis so that if the pressure falls below the predetermined pressure by a certain amount during the predetermined duration of the test, the pressure switch returns to its one state thereby giving a signal denying the integrity. Integrity is confirmed by the pressure switch remaining in its another state during the test.

Abstract: A pulse width modulated solenoid-actuated valve and a vacuum-actuated valve for cooperatively associated such that the purge system possesses both accurate control at low purge flows and the capacity for handling much higher flows. The two valves are in parallel paths between the canister and the manifold. Below a certain duty cycle of the solenoid-actuated valve, only its path is open. At higher duty cycles, both flow paths are open. An orifice is provided in the flow path containing the solenoid-actuated valve so that as this valve increasingly opens, a vacuum signal at a tap between the orifice and the solenoid-actuated valve also increases. This vacuum signal is applied to a control port of the vacuum-actuated valve to cause the latter to open upon attainment of a certain flow through the solenoid-actuated valve.

Abstract: A carrier for use as a stiffening member, e.g. in polymeric extrusions used in the motor and building industries, being of elongate strip form and having a plurality of longitudinally spaced, transversely extending members therein, wherein the said members are maintained in their spaced relationship by means of at least one sinuous or zig-zag securing member running longitudinally of the carrier and being welded or otherwise rigidly secured to each transversely extending member.The or each securing member may be wire having a generally uniform zig-zag construction, wherein a substantial part of a corrugation or zig-zag thereof is located between adjacent transversely extending members, or may be wire of a more extended sinuous construction such that its transverse positioning within the carrier is varied along the length of the carrier.

Abstract: Improved idle purging is obtained in a regulated canister purge solenoid valve by communicating the atmospheric chamber space of the regulator mechanism to atmosphere through the canister and providing in the movable wall of the regulator mechanism an orifice which is closed by abutment of a surrounding portion of the movable wall with an internal surface of the atmospheric chamber space when the engine is off, but is opened when that surrounding portion of the movable wall leaves that internal surface of the atmospheric chamber space upon engine running.