Abstract: A leak test system and method for a motor vehicle fuel system. A pump forces air under pressure into vapor containment space. The pump operates in accordance with steps established by a processor. The pump creates superatmospheric pressure in the space during an initial charging phase step, and after completion of that step, the pump performs a measurement phase step that forces pulses of air into the space in a succession of pulse bursts. Each burst contains a succession of individual pulses, preferably in equal numbers, and each successive burst is delayed from an immediately prior burst by a time interval substantially longer than the time intervals between individual pulses in each burst, preferably by constant time intervals. The processor processes data corresponding to a measurement of pressure in the space after the occurrence of at least one of such bursts and as a result indicates leakage from the space.

Abstract: A fuel vapor leakage inspection apparatus utilizes a fuel tank, an adsorption container which houses an adsorbent for adsorbing fuel vapor generated in the fuel tank, and an exhaust device for communicating between the adsorption container and an intake pipe. Furthermore, the apparatus utilizes a pressure means that pressurizes or depressurizes a fuel vapor path formed from the fuel tank through the adsorption container to the exhaust device. A leakage detection means detects leakage from the fuel vapor path after the fuel vapor path is pressurized or depressurized by the pressure means while a calculation means calculates an amount of fuel vapor adsorbed, and a control means determines if the pressure means should execute leakage inspection of the fuel vapor path in accordance with the amount of the fuel vapor calculated by the calculation means.

Abstract: A method for gas pressurizing of parts for leakage detection including an enhanced process for reliably achieving full gas pressurization of the part to a predetermined test pressure value and monitoring for various errors which may occur during pressurization, and after pressure and temperature settling, taking an instantaneous snapshot pressure measurement and calculating two pressure thresholds. A snapshot pressure measurement is compared to a slam threshold value after termination of the slam time period and if pressure remains above the threshold signaling “good” and terminating the test. If the measured pressure reads below the slam threshold during slam test then the slam test terminates and the standard threshold test will then be performed repeatedly over the total test time which will yield a good result unless the pressure goes below the standard threshold during total test time which will then yield a bad part result.

Abstract: A leak detection system for a vehicle includes a fuel system and a controller. The controller communicates with the fuel system to detect a fuel filling event. The controller initiates a vapor leak test of the fuel system and terminates the vapor leak test if a fuel filling event is detected.

Abstract: The invention is directed to a method for operating an internal combustion engine including an actuating member in an air supply for adjusting an air mass to be supplied to the engine. In the method, a position of the actuating member is adapted to an instantaneous operating state by a short-time adaptation and a position of the actuating member is adapted by a long-time adaptation to compensate for longer term influences on the position of the actuating member. For a long-time adaptation, a long-time adaptation value is formed for the position of the actuating member in dependence upon a minimum short-time adaptation value for the position of the actuating member which was formed during the short-time adaptation. A leakage in the air supply is diagnosed in dependence upon the long-time adaptation value.

Abstract: A fuel system with a pressure-sensitive monitor accumulates multiple pressure-related sample points and estimates the general trend of pressure change in a fuel system over time, thereby detecting the presence or absence of a fuel vapor leak in the fuel system.

Abstract: A device and method for signaling differential pressure change occurring during leak testing of an evaporative emission control space in a motor vehicle fuel system. A casing has sensing ports one of which is communicated to a reference pressure, such as atmospheric pressure, and another of which is communicated to sense pressure in the evaporative emission control space. As difference between the reference pressure and the pressure in the control space changes, the net magnetic flux acting on a magnetoresistive sensor changes. The sensor is electrically connected to the vehicle electrical system for signaling the differential pressure. The device may be used for both positive and negative pressure leak testing.

Abstract: A non-intrusive method and arrangement for detecting the aging of an oxygen sensor, without increasing tailpipe emissions, is provided. The method detects an aging oxygen sensor, located between a motor vehicle engine and a catalytic converter, by sampling a series of oxygen level signals taken over a calibratable time block only when at least one engine operating condition satisfies a predetermined criterion whereunder the method will not intrude upon the engine controller's ability to minimize undesirable exhaust emissions. After a series of signal processing, the samplings are then compared to calibratable thresholds in order to determine the aging degree of the oxygen sensor.

Abstract: A method for the leak testing of a motor vehicle fuel tank and associated evaporative emissions control system is provided. Nitrogen, compressed air or other gases are used to pressurize the system. The time required for pressurization is used to determine the tank headspace volume. The system pressure is then monitored for 120 seconds. The pressure drop in this period is then compared with a pass-fail value cutpoint from a look-up table stored in a computer attached to the testing apparatus. A pass-fail determination is then made. The pass-fail value cutpoint is pre-determined for a specified vapor volume and estimated liquid fuel temperature, as well as time of year, so that systems with leaks larger than a specified diameter consistently fail the test, while systems with leaks smaller than this value consistently pass the test. The test pass-fail criterion is thus compensated for the conditions (tank fill level and fuel temperature, and seasonal variations in fuel volatility) experienced the actual test.

Abstract: An apparatus and a method for testing the integrity of fuel tanks for leaks are disclosed. A microprocessor controls the pressurization of the fuel tank and then selectively allows the gas within the fuel tank to decay through any leaks within the tank or through the combination of the leaks within the tank and a reference orifice. By computing and comparing the time required for the tank pressure to decay between predetermined pressure levels due to any tank leaks with a standard decay time, a determination can be made whether the leakage rate through the tank is acceptable. Greater resolution, if necessary, is provided by computing the ratio of the time required for the tank pressure to decay between predetermined pressure levels through the combination of any tank leaks and a reference orifice versus only through the tank leaks and compares same against a standard ratio to determine whether the tank leakage rate is acceptable.

Abstract: A method for the leak testing of a motor vehicle fuel tank and associated evaporative emissions control system is provided. Nitrogen, compressed air or other gases are used to pressurize the system. The time required for pressurization is used to determine the tank headspace volume. The system pressure is then monitored for 120 seconds. The pressure drop in this period is then compared with a pass-fail value cutpoint from a look-up table stored in a computer attached to the testing apparatus. A pass-fail determination is then made. The pass-fail value cutpoint is pre-determined for a specified vapor volume and estimated liquid fuel temperature, as well as time of year, so that systems with leaks larger than a specified diameter consistently fail the test, while systems with leaks smaller than this value consistently pass the test.

Abstract: A pressure-changing device of a leak check system for a fuel vapor treatment system has a pressure chamber formed in a peripheral space of a communicating path connecting a pump with an electromagnetic valve, the pressure chamber being deviated from flow delivered by the pump. The electromagnetic valve is opened to connect the communicating path with a canister. Then, a purge valve is closed and the pump is turned on to change pressure in a fuel vapor path. A pressure sensor attached on a side wall of the pressure chamber detects pressure in the communicating path to determine pressure in the fuel vapor path. The leak check system judges existence of leak in the fuel vapor treatment system from pressure in the fuel vapor path.

Abstract: An abnormality detecting device for an evaporative fuel processing system is disclosed. The evaporative fuel processing system includes a fuel tank, a canister for trapping evaporative fuel generated in the fuel tank, a charging passage for connecting the fuel tank and the canister, a tank pressure regulating valve provided in the charging passage, a bypass passage bypassing the tank pressure regulating valve, a bypass valve provided in the bypass passage, and a pressure sensor provided in the fuel tank or in the charging passage at a position between the tank pressure regulating valve and the fuel tank. The pressure in the canister is reduced to a pressure which is lower than the atmospheric pressure in the condition where a valve closing command signal for the bypass valve is output.

Abstract: In a method for checking the tightness of a tank-venting system of a vehicle, one tightly closes the tank by means of a blocking device after shutting off the vehicle. Thereafter, one detects the pressure, which develops in the tank system, with a pressure sensor and draws a conclusion as to a leak based on the pressure trace over time. An arrangement for checking the tightness in accordance with this method is suggested.

Abstract: A fixture for holding a gas turbine engine blade having an airfoil extending outward from a shank and a dovetail extending inward from the shank for attaching the blade to a disk of the engine. The dovetail includes at least one pair of protrusions extending fore and aft along opposite sides of the blade. Each of the protrusions including a pressure face generally facing the airfoil of the blade for engaging the disk to retain the blade in the disk during operation of the engine. The fixture includes a support for receiving the dovetail and a clamp mounted adjacent the support for movement between a clamped position in which the clamp engages the dovetail to hold the dovetail against the support and a released position in which the clamp disengages the dovetail to permit removal of the blade from the fixture.

Abstract: A fuel system with a pressure-sensitive monitor accumulates multiple pressure-related sample points and estimates the general trend of pressure change in a fuel system over time, thereby detecting the presence or absence of a fuel vapor leak in the fuel system.

Abstract: An apparatus detects leak in a fuel vapor treatment system which is referred to as an evaporation system. The apparatus measures a required time T2 that is required for decreasing pressure in the evaporation system from P0 to P1 while opening a base leak hole that provides known amount of leak. Then, a required time T1 that is required for decreasing pressure from P0 to P1 is measured while closing the base leak hole. The apparatus compares the required times T1 and T2 in order to detect a leak other than the base leak hole. In this process, a specified coefficient that is defined in accordance with the base leak hole is taken into consideration. It is possible to detect the leak of the evaporation system with high accuracy even when the amount of remaining fuel is extremely large.

Abstract: A tool set for detecting leakage of vehicle engines in the invention includes a support holder having a base, a frame, an adjusting plate and a coupling member; a leakage-detecting device having at least one connecting member and a connector-tube assembly provided with a pressure gauge and a switch. In using, firstly use the support holder to hold an axle center of an engine crankshaft stationary. Secondly, screw the connecting member with a spark plug hole and connect the connector-tube assembly with a general air pump through which air is injected into an engine cylinder. Finally, when the cylinder is full of air, turn off the switch and observe an indicator needle of the gauge for reversing movements to determine whether any leakage occurs from the engine, thus providing a tool set for detecting leakage of vehicle engines that is timesaving, laborsaving and convenient in operation by a single person.

Abstract: A test fixture for testing directional pilot valves as used in connection with turbine engine thrust reversers, and an associated method of use. In a particular embodiment, the test fixture has a base and at least one support mounted to the base to support the directional pilot valve. At least one fastener permits attachment of the directional pilot valve to the support. An adjustable actuator is also mounted to the base and is capable of stroking the directional pilot valve to simulate valve positions that may be encountered in operation of the valve. The adjustable actuator is also capable of maintaining a force, as set by a technician, against the directional pilot valve.

Abstract: A fuel-vapor-processing system for an engine has a canister for accumulating fuel evaporation gas. The system has a leak-check apparatus for checking a leak on passages. The leak-check apparatus includes a leak-check means for carrying out leak-check processing when the engine if in a stopped state. The leak-check means operates only if a predetermined condition is satisfied. It is thus possible to reduce the number of times the leak-check processing is carried out and, hence, possible to reduce power consumption. For example, only if a relatively small leak is detected when the engine is in a running state, the leak-check processing is carried out in a stopped state to verify existence of such a leak. In the leak-check processing, the temperature of fuel, detected by a sensor or an estimated value, may be taken into consideration.

Abstract: An improved method of testing for evaporative emission system leaks monitors vacuum decay in a closed system so that the effects of fuel tank expansion during the test interval are minimized. In a first embodiment pass/fail criteria are established in terms of the time required for the system pressure to decay by a calibrated amount for a predetermined leak size. A leak at least as large as the predetermined leak is detected if the measured time is shorter than a calibrated time. The effects of fuel tank expansion are minimized because the changes in fuel tank volume occur primarily due to the pressure differential across the tank, as opposed to the leak size, and the changes that occur during the test are essentially the same for any leak size under consideration.

Abstract: Apparatus and methods for airflow testing, especially for air testing of gas turbine components on an airflow test bench. Various embodiments of the present invention include the use of a measurement section downstream of the component being tested. The measurement section, in one embodiment, includes apparatus for measurement of gas properties at a plurality of spaced-apart radial locations and/or a plurality of spaced-apart circumferential locations. In another embodiment, the invention includes a method for testing a component including a comparison of gas properties measured in both forward and reverse flow directions.

Abstract: A tool set for detecting leakage of vehicle engines in the invention includes a support holder having a base, a frame, an adjusting plate and a coupling member; a leakage-detecting device having at least one connecting member and a connector-tube assembly provided with a pressure gauge and a switch. In using, firstly use the support holder to hold an axle center of an engine crankshaft stationary. Secondly, screw the connecting member with a spark plug hole and connect the connector-tube assembly with a general air pump through which air is injected into an engine cylinder. Finally, when the cylinder is full of air, turn off the switch and observe an indicator needle of the gauge for reversing movements to determine whether any leakage occurs from the engine, thus providing a tool set for detecting leakage of vehicle engines that is timesaving, laborsaving and convenient in operation by a single person.

Abstract: An apparatus and a method for managing fuel vapor pressure in a fuel system that supplies fuel to an internal combustion engine. The fuel vapor pressure management apparatus performs leak detection on a headspace of the fuel system, performs excess negative pressure relief of the headspace, and performs excess positive pressure relief of the headspace. The apparatus includes a housing, a pressure operable device, and a printed circuit board. The housing defines an interior chamber. The pressure operable device separates the interior chamber into first and second portions. And the pressure operable device includes a poppet that moves along an axis and a seal that is adapted to cooperatively engage the poppet. The printed circuit board is supported by the housing in the interior chamber. And the printed circuit board includes a sensor that is adapted to be actuated by movement of the poppet along the axis.

Abstract: A method of leak detection in a closed vapor handling system of an automotive vehicle, wherein an engine is shut off, implemented by a system, the method including obtaining a start temperature and start pressure, providing an evaluation temperature, calculating a temperature differential between the start temperature and the evaluation temperature, evaluating whether a pressure switch is closed if the temperature differential is greater than a temperature control value, incrementing a time counter if the pressure switch is not closed and comparing the time counter to a time control value if the pressure switch is not closed.

Abstract: There is provided a leakage determination system for an evaporative fuel processing system, which, even when pressure within the evaporative fuel processing system is temporarily increased e.g. due to an increase in the amount of generation of evaporative fuel in a fuel tank, is capable of performing an accurate leakage determination by eliminating the influence of the temporary rise in the pressure within the evaporative fuel processing system on the leakage determination. A pressure sensor detects pressure within the evaporative fuel processing system. Negative pressure is introduced from the intake system into the evaporative fuel processing system, whereby the pressure within the evaporative fuel processing system is reduced until the detected pressure becomes equal to a predetermined negative pressure. After the pressure reduction, the negative pressure is introduced from the intake system into the evaporative fuel processing system under predetermined conditions.

Abstract: A method detects leakages in a motor vehicle air spring system which includes a plurality of air springs and has a level control arrangement. The level control arrangement includes: an electronic control apparatus; a plurality of elevation determination sensors associated with corresponding ones of the air springs; a pressure sensor; a plurality of air spring valves corresponding to respective ones of the air springs and a compressor. The elevation determination sensors and the pressure sensor are connected to the control apparatus for supplying signals thereto. The control apparatus functions to process the signals for controlling the air spring valves and the compressor for controlling the motor vehicle upwardly or downwardly in elevation.

Abstract: A combination solenoid operated flow control valve and solenoid operated by-pass valve and pressure transducer are disposed in a common housing with a common electrical receptacle for connection thereto. The pressure transducer senses differential pressure across a metering orifice. The pressure transducer measures flow through the metering orifice during leak testing. A vacuum is drawn in the system for leak testing. The by-pass valve is opened to bypass the metering orifice and permit full flow to the flow control valve during normal engine operation.

Abstract: A failure diagnostic system reduces the internal pressure of a fuel tank to a predetermined negative pressure, seals off the fuel tank from the air, and then determines whether an evaporated fuel processing system has failed or not by monitoring an increase in pressure in the fuel tank. In determination, the failure diagnostic system compares a detected pressure in the fuel tank with a reference value that is increased by a predetermined rate. The failure diagnostic system stops update of the detected pressure if the detected pressure becomes higher than the reference value, and resumes update of the detected pressure if the detected pressure becomes lower than the reference value. It is therefore possible to accurately determine whether the evaporated fuel processing system has failed or not even if the pressure in the fuel tank is rapidly increased.

Abstract: The present invention relates a method of detecting leaks and blockages in a fuel system. The leaks are detected using a RAMPOFF mode and a TANK mode. The RAMPOFF mode modifies the evaporative diagnostic purge logic to increase the ramp down rates of the evaporative purge duty cycle to aggressively shut off the purge solenoid valve for tests used to detect leaks as small as 0.02 inches in diameter. The TANK mode modifies the evaporative diagnostic purge logic to support aggressive purging requirements for tests used to detect larger leaks of greater than 0.04 inches in diameter. The MASS FLOW mode modifies the evaporative diagnostic purge logic to hold a constant purge mass flow rate necessary to detect blockages across a vent solenoid valve. The RAMPOFF mode, TANK mode, and MASS FLOW modes support evaporative diagnostics that are run continuously within a fuel system when acceptable engine operating conditions are present.

Abstract: A fuel vapor leakage inspection apparatus utilizes a fuel tank, an adsorption container which houses an adsorbent for adsorbing fuel vapor generated in the fuel tank, and an exhaust device for communicating between the adsorption container and an intake pipe. Furthermore, the apparatus utilizes a pressure means that pressurizes or depressurizes a fuel vapor path formed from the fuel tank through the adsorption container to the exhaust device. A leakage detection means detects leakage from the fuel vapor path after the fuel vapor path is pressurized or depressurized by the pressure means while a calculation means calculates an amount of fuel vapor adsorbed, and a control means determines if the pressure means should execute leakage inspection of the fuel vapor path in accordance with the amount of the fuel vapor calculated by the calculation means.

Abstract: Fuel vapor in a fuel tank (1) is purged into an intake passage (8) of an engine (10) through a purge vent (2, 4, 6). The controller (21) determines whether a leak is present in a purge vent from the fuel tank (1) to a purge control valve (11). The determination process comprises a pull-down process in which a pressure in the purge vent is reduced using a negative pressure in the intake passage (8) and a leak-down process of sealing the purge vent at the reduced pressure and monitoring the pressure variation. The controller (21) calculates an error equivalence amount (DVPII), a pressure component corresponding to sloshing in the fuel tank (1) during the leak-down process, and determines the presence of a leak in a highly accurate manner based a corrected pressure (DVP5A) in which the monitored pressure variation is corrected using the error equivalence amount (DVPII) (S22).

Abstract: A device and method for signaling differential pressure change occurring during leak testing of an evaporative emission control space in a motor vehicle fuel system. A casing has sensing ports one of which is communicated to a reference pressure, such as atmospheric pressure, and another of which is communicated to sense pressure in the evaporative emission control space. As difference between the reference pressure and the pressure in the control space changes, the net magnetic flux acting on a magnetoresistive sensor changes. The sensor is electrically connected to the vehicle electrical system for signaling the differential pressure. The device may be used for both positive and negative pressure leak testing.

Abstract: A leak determining apparatus for an evaporated fuel treatment system is provided for executing a leak determination for an evaporated fuel treatment system without suspending it even in such a condition that variations in fuel could occur, thereby accurately providing a leak determination result. The leak determining apparatus calculates a reference differential pressure difference DDPZ as a difference between differential pressures of an inner tank pressure PTANK detected at two times in a leak check mode, i.e., a differential pressure DPZ2 and a differential pressure DPZ1 detected a predetermined slosh determination time before, and compares the reference differential pressure difference DDPZ with a slosh determining threshold value DDPZG to determine the presence or absence of sloshing.

Abstract: An apparatus for inspecting the airtightness of a gas sensor includes an atmosphere-side jig located at a base end side of a sub assembly of the gas sensor, and a measurement gas-side jig located at a distal end side of the sub assembly. The measurement gas-side jig includes an air chamber, a socket receiving the sub assembly, and a high-pressure air source supplying a high-pressure air to the air chamber. The atmosphere-side jig includes a sealed chamber, a socket receiving the sub assembly, an airtight sealing portion, a low-pressure air source supplying the sealed chamber with a pressure lower than a pressure of the high-pressure air supplied to the air chamber, and a sensor portion leading to the sealed chamber.

Abstract: The present invention relates to a method and system for detecting air leaks in tires and in a tire testing machine. Each of the tires is mounted on the tire testing machine; inflated with an air flow from an inflation system to a first pressure; and maintained at the first pressure by continued supply of air from the inflation system into the tire. The flow of the continued supply of air is measured with a calorimetric flow sensor calibrated to output a sensor signal having a full scale value corresponding to an identical model tire mounted on the tire testing machine with no air leaks in the model tire or the testing machine. The flow of the continued supply of air is compared with an averaged flow for previously measured tires mounted on the tire testing machine with no air leaks in the tires or the testing machine. A control signal indicating an air leak is outputted if the sensor signal is 20% to 80% of the full scale value.

Abstract: The present invention provides a malfunction diagnostic apparatus for an evaporated fuel purge system in an internal combustion engine, capable of detecting abnormalities such as looseness or clogging in the purge line between a purge valve and an engine intake passage. An electric pump 14 is turned on when a purge valve 5 is in a closed state and a selector valve 20 is in an open state. After the lapse of a given time period Tref, a load-current initial value I1 of the electric pump 14 is detected at the moment switching the selector valve 20 to a closed state. After the lapse of a given time period Tpump, the purge valve 5 is switched to an open state, and a load-current final value at the moment after the lapse of a given time period Tpurge. As in the curve A, when a load current final value I2A is equal to or less than the load current initial value I1, it is determined that the gaseous communication state in the purge line between the purge valve 5 and the intake passage is normal.

Abstract: An evaporative emission leak detection system provides for detecting a leakage of a fuel vapor evaporating in a fuel tank by using a pressure difference between an inside and outside of the fuel tank. The system includes a pump for providing the pressure difference between the inside and outside of the fuel tank, a brushless motor for operating the pump, a first passage connecting to the fuel tank, a second passage connecting to the outside of the fuel tank, and a switching device for switching connections between the pump and at least one of the first passage and the second passage. The first passage has an adsorbent for adsorbing the fuel vapor. This system ensures a long life time and high accuracy of the leak detection.

Abstract: In an evaporative emission control system, when an engine is running, a negative pressure generated in an air intake pipe of the engine is introduced into a fuel tank through a negative pressure intake line. When the engine halts, a purge valve provided on a purge line connecting the intake pipe and a canister is closed and defines a closed space between the purge valve and the fuel tank. After the negative pressure in the fuel tank is introduced into the closed space and the closed space is maintained under a continuous and uniform negative pressure, the system starts a leak check. Because the negative pressure intake line is provided with a negative pressure maintaining valve, the fuel tank is maintained under the negative pressure when the engine is running.

Abstract: A method for inspecting the integrity of diesel exhaust filter by introducing air under pressure through one end of the structure and detecting the presence of air flow at an opposing end surface. The diesel exhaust filter is tested green.

Abstract: In order to set the nozzle opening pressure for an injection nozzle, in particular for a diesel injection nozzle, to an accuracy of around ±1%, the method provides that the injection needle is first pressed against the valve seat with a closing force (Fz), and then when two different test pressures (pU, p1, p2) are applied to the injection nozzle the test forces (Fz, F1, F2) effective on the injector needle are measured, with the pressure stage (A) being determined from the measured test forces and the test pressures applied, and finally using the pressure stage (A) a nozzle valve with a suitable valve spring force (Fv) is selected to correspond to the desired nozzle opening pressure (pD).

Abstract: An on-board evaporative emission leak detection system and method that detects leakage from an evaporative emission space of a fuel system of an automotive vehicle. A test includes an initialization, or stabilization, phase during which a differential between pressure in the evaporative emission space and atmospheric pressure is created, and then varied, over time, within a range of differential pressures suitable for performing a leak detection test. This varying of pressure differential alternately increases the created pressure differential above a nominal pressure differential and decreases the created pressure differential below the nominal pressure differential. The leak detection test is then performed.

Abstract: A leakage detecting device has a cover, a first cup and a second cup. The cover is mounted on the opening of the water tank and has a through hole. The first cup is connected to the cover and communicates with the through hole in the cover. A tortuous air channel is defined in the first cup. The second cup is mounted on the first cup and has a second tortuous air channel communicating with the first tortuous air channel in the first cup. Accordingly, the leakage of cylinders of the vehicle engine can be precisely detected from the water tank of the vehicle.

Abstract: A method for checking the tightness of a tank-venting system of a vehicle wherein one introduces an overpressure or underpressure compared to the atmospheric pressure via a pressure source alternately into the tank-venting system and a reference leak of a defined size connected in parallel to the tank-venting system over a pregiven time interval and wherein one detects at least one operating characteristic variable of the pressure source when introducing the pressure into the tank-venting system (tank measurement) as well as when introducing the pressure into the reference leak (reference measurement) and wherein one compares the two measurements and, when there is a deviation of the tank measurement from the reference measurement by a pregivable value, one draws a conclusion as to a leak when there is a deviation of the tank measurement from the reference measurement by a pregivable value and the method is characterized in that one draws a conclusion as to the operability of the tank-venting valve of the tan

Abstract: A lined tubular system and method provides for the manipulation and control of annular fluids in channels (18) between the tubular (10) and the liner (17). This structure allows for profiling of the exterior wall of a liner such that one or more continuous channels are provided along the length of the lined tubular system. The system may also include one or more non-crushable members or tubes between the liner's exterior surface and host tubular's interior surface. Rounded, granular particles or spacers in the annulus between the liner and host may provide an alternative path for fluid flow. The particles or spacers may be uniformly or randomly distributed in the annulus.

Abstract: A leak test system and method for a motor vehicle fuel system. A pump forces air under pressure into vapor containment space. The pump operates in accordance with steps established by a processor. The pump creates superatmospheric pressure in the space during an initial charging phase step, and after completion of that step, the pump performs a measurement phase step that forces pulses of air into the space in a succession of pulse bursts. Each burst contains a succession of individual pulses, preferably in equal numbers, and each successive burst is delayed from an immediately prior burst by a time interval substantially longer than the time intervals between individual pulses in each burst, preferably by constant time intervals. The processor processes data corresponding to a measurement of pressure in the space after the occurrence of at least one of such bursts and as a result indicates leakage from the space.

Abstract: A cap for a vehicle radiator has a body, a sealing member, a biasing member and a connector. The body is detachably mounted on the mouth of the radiator. A protrusion with a central hole is mounted on the body. The sealing member is slidably attached to the body for sealing the opening in the radiator and has a flange, a seal and a stub. The stub extends upward from the top of the flange and extends through the central hole in the protrusion on the body. The outer periphery of the stub contacts with the inner surface of the central hole in the body. Accordingly, the stub can be securely held on the body to prevent a gap being defined between the seal and the opening. This gap prevention can avoid leak between the sealing member and the mouth occurring during the leak-detecting process of the radiator.

Abstract: A method detects leakages in a motor vehicle air spring system which includes a plurality of air springs and has a level control arrangement. The level control arrangement includes: an electronic control apparatus; a plurality of elevation determination sensors associated with corresponding ones of the air springs; a pressure sensor; a plurality of air spring valves corresponding to respective ones of the air springs and a compressor. The elevation determination sensors and the pressure sensor are connected to the control apparatus for supplying signals thereto. The control apparatus functions to process the signals for controlling the air spring valves and the compressor for controlling the motor vehicle upwardly or downwardly in elevation. In the method, at a first time point (t1), the elevation-distance values (h1) and the corresponding air pressure (p1) are measured for each air spring and the elevation-distance values are stored with the time of measurement with the first time point (t1).

Abstract: A leak detection system for a fuel system of an automotive vehicle has a diaphragm pump that is repeatedly stroked to pressurize vapor containment space of the fuel system during a leak detection test. A restriction is disposed between the pump and the space being pressurized to cause a real time pressure trace of pressure between the pump and the restriction to comprise a succession of pulses having peaks and valleys. Data from the first pump burst of the trace is used to adjust the number of times the pump is stroked during subsequent bursts to maintain substantially constant mass airflow into the space during each burst, thereby compensating for change in pump efficiency.

Abstract: A method and apparatus are disclosed for detecting leakage in the fuel supply to the injectors of an engine in which the individual injectors are connected to a fuel supply rail to which fuel from a reservoir is supplied under pressure by a fuel pump. The pressure within the fuel rail is monitored and it is determined when a parameter of a pressure surge in the fuel supply rail resulting from a rapid transition from high to low engine load fails to reach a reference value.