Abstract: A device which determines a motion parameter with a sensor having a plurality of sensor elements coupled to one another, in which the motion parameter corresponds to a rotational speed. The device includes a starter loop for putting the sensor in a state of excitation via a starter signal via at least one of the sensor elements and for generating a sensor quantity, with the sensor quantity being a measure of a response of the sensor to the starter signal, and the starter signal having a substantially constant amplitude. A detector loop coupled to at least one of the sensor elements is also provided in the device for providing a measurement signal correlating with the motion parameter.

Abstract: The device for detecting leaks in a fuel supply system for an internal combustion engine includes an electronic engine control unit (23) which tests for an engine overrunning mode, closes the injection valves and shuts off the fuel pump (11) if the overrunning mode is detected. Then this control unit (23) determines a pressure gradient (gradp) of a fuel supply line pressure measured by a pressure sensor (24) or a differential pressure gradient (grad .delta.p) of a differential pressure between fuel supply and return lines (13,17) measured by a differential pressure sensor (25) after the injection valves (15) are closed. Then it compares the pressure gradient (gradp) or differential pressure gradient (grad .delta.p) with a predetermined threshold (SW) or respective upper and lower thresholds (SW.sub.o, SW.sub.u) to determine if a leak has occurred.

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. Interior space of the module's enclosure is communicated to atmosphere. A pump is disposed within space and has an inlet communicated to the interior space and a flow passage at its outlet to allow the pump to create pressure in the evaporative emission space suitable for performance of a leak test. A vent valve is disposed within space and is selectively operable to vent and not vent the flow passage to space. An electromagnet actuator has a single electric coil that operates both the pump and the vent valve by cantilever-mounted armatures responsive to electric control current in the coil having a first current component for controlling the pump and a second current component for controlling the vent valve.

Abstract: A system and method of detecting a leak in an evaporative emissions system for a vehicle includes measuring a physical disturbance of the vehicle with a sensory system and providing a sensory signal (311, 313, 315). Then, comparing the sensory signal (311, 313, 315) to a threshold (405) and generating a diagnosis signal (407, 413) having a "valid test" state, when the sensory signal does not exceed the threshold, and generating the diagnosis signal having an "invalid test" state, when the sensory signal exceeds the threshold. And, executing an evaporative emissions system leak test while the provided diagnosis signal indicates the "valid test" state, and aborting the evaporative emissions system leak test (505) when the diagnosis signal indicates the "invalid test" state.

Abstract: A fuel cap tester kit containing a plurality of fuel cap adapters, wherein each adapter has a mouth opening, outer rim, cap receiving chamber, air supply passageway and a fuel cap connection opening and with each fuel cap opening being configured to engage and retain a different and specifically configured fuel cap, and wherein each adapter is also provided with a threaded base connection that cooperates with a complimentary threaded connection on a test base that is fluidly connected to a pressure source and tester apparatus and wherein the base connectors of each adapter are configured alike so that each adapter can be connected to the single threaded connector in the test base to permit testing of different size fuel caps dependent on the adapter threaded into the test base, where the tester kit is used to decide upon quality of fuel caps under test by determining a leakage rate of pressurized air from the cap-receiving chamber through the mouth opening.

Abstract: The invention relates to a method for selectively testing leakage of combustion chambers in cylinders of internal combustion chambers when the engine is operated with the combustion process suppressed. The internal combustion engine is provided with means for measuring the crank shaft rotation angle and for measuring the instantaneous rotational speed of the crank shaft and wherein the leakage of the combustion chambers is tested during expansion of the gas mixture during the combustion stroke and/or during compression of the gas mixture during the compression stroke of the cylinders of the internal combustion engine.

Abstract: A testing mechanism for detecting fluid leaks in a torque converter utilizing a seal which closes a passage through the torque converter hub to the interior of the housing of the torque converter. Fluid is then charged into the torque converter and maintained at a certain pressure. The torque converter is then immersed in a liquid found in a container to permit the observation of the escape of fluid from the torque converter.

Abstract: An engine component of the type having a cavity therein through which cooling water can circulate, there being ports which lead from a face of the engine component into the cavity, is pressure tested by closing the ports and by pressing port closing elements onto the face so as to blank off the ports. The cavity is then pressurised and the engine component observed for seepage of water or the appearance of bubbles. The port closing elements are pressed onto the face by means of a transparent, laminated glass plate which is held in a steel frame by means of an elastomeric adhesive. Between the glass plate and a pressure bearing face of the steel frame there is a layer of elastomeric material.

Abstract: A motion sensor having a micromachine sensing element and electrodes formed on a silicon chip. The sensing element includes a ring supported above a substrate so as to have an axis of rotation normal to the substrate. Surrounding the ring is at least one pair of diametrically-opposed electrode structures. The sensing ring and electrode structures are configured to include interdigitized members whose relative placement to each other enables at least partial cancellation of the effect of differential thermal expansion of the ring and electrodes. As a result, the performance of the motion sensor is, to first order, insensitive to temperature variation. The sensor further includes circuitry for creating and detecting an electrostatic force between the interdigitized members of the sensing ring and electrode structures.

Abstract: In a motorcar having a compressed fuel cylinder charged with a compressed fuel disposed in a compartment, pipes connected to the fuel cylinder within the compartment are connected to a joint unit penetrating a partition wall partitioning the compartment from an outside and the joint unit is connected to pipes connected to an internal combustion engine and the like out of the compartment. A fuel charge passage, a fuel supply passage and a relief passage in a cylinder cap of the fuel cylinder and a fuel charge passage, a fuel supply passage and a relief passage in an interior side of the joint unit are connected with each other through an interior charge pipe, and interior supply pipe and an interior fuel relief pipe, respectively. A fuel charge pipe, a fuel supply pipe and a relief pipe out of the compartment are connected to a fuel charge passage, a fuel supply passage and a relief passage in an exterior side of the joint unit.

Abstract: A non pressurized internal separator leak test method is disclosed for a two pass condenser in which helium is injected below a vertical manifold tank separator, allowed to rise, and detected or not detected above the separator. The helium cannot reach the upper side of the separator other than through a separator leak path, because it will not flow sideways down the flow tubes.

Abstract: A vibrating gyroscope includes a vibrator having a triangular prism shaped vibrating body and piezoelectric elements. An oscillation circuit is connected between two piezoelectric elements and another piezoelectric element. Output signals from two piezoelectric elements are applied to input terminals of a differential circuit. The differential circuit is connected to a synchronous detecting circuit, and the synchronous detecting circuit is connected to a smoothing circuit. A temperature compensating capacitor is connected between two piezoelectric elements that are connected to the differential circuit. The oscillation circuit consists of an amplifier and a phase shifter having a resistor and a capacitor. As the capacitor used in the phase shifter, the temperature compensating capacitor may be used.

Abstract: A cylinder head for an in-cylinder injection spark-ignition type internal combustion engine is formed with an injection passage for providing communication between a fuel injection valve and a combustion chamber. The injection passage includes a first and second passage sections disposed on the fuel injection valve side and on the combustion chamber side. The first passage section is formed, for example, into a truncated cone shape or a right circular cylindrical shape so that the cross sectional area decreases toward the fuel injection valve side or the area is constant over its entire length. The second passage section is formed to have the cross sectional area which increases toward the combustion chamber side. The fuel injected from the fuel injection valve flows into the combustion chamber via the injection passage having a gradually increasing cross sectional area, so that turbulence of fuel spray due to sudden divergent flow does not occur, resulting in an improved fuel combustion efficiency.

Abstract: An on-board diagnostic system for an evaporative emission control system of an internal combustion engine powered vehicle employs a leak detection module that is fluid connected in a vent passage for the evaporative emission space. The leak detection module contains an electric motor driven impeller, a solenoid operated valve assembly that is selectively operable to three positions, and a pressure-responsive switch whose switching characteristic possesses hysteresis corresponding to an upper regulating limit and a lower regulating limit.

Abstract: The present invention includes a water leakage testing device for a thermostat of a water-cooled internal combustion engine including a water cooling supply portion that supplies stored cooling water through a supply line at a predertimined pressure, a hydraulic flow measuring portion that measures hydraulic flow of the cooling water supplied from the supply portion, and a supporting portion that supports and seals the lower part of the thermostat.

Abstract: A vibration-type angular velocity detector is for accurately correcting temperature-induced variations of an angular velocity signal without using a temperature sensor. A driving piezoelectric element, a detecting piezoelectric element and reference piezoelectric element are disposed on a vibration element. Using an output signal of the reference piezoelectric signal, a feedback control loop for applying driving voltage to the driving piezoelectric element is provided using an amplifier, a phase-shifting circuit, a rectifier, a reference voltage generator, a differential amplifier and a multiplier so as to vibrate the vibration element at a fixed amplitude. In addition, using an output signal of the detecting piezoelectric element at the time of vibrating the vibration element, an angular velocity signal is output. Here, the output voltage of the differential amplifier is a signal corresponding to the temperature of the vibration element.

Abstract: Internal combustion engine cylinder compression ratio measurement is provided by applying a train of pressure pulses to an engine cylinder, measuring time rate of change in pressure within the cylinder and estimating a volume of air within the cylinder from the measured time rate of change. The cylinder air volume may be compensated for such effects as change in cylinder air temperature away from a calibration temperature or cylinder leakage. The time rate of change in pressure is measured at an engine angular position corresponding to a known volume within the cylinder, for example an engine angular position corresponding to the cylinder top dead center position, and cylinder compression ratio is determined from the estimated volume of air in the cylinder and the known cylinder volume.

Abstract: A method and apparatus for testing and filling hydraulic assemblies such as a hydraulic clutch control assembly for a motor vehicle.

Abstract: An evaporative emission tester is used to evaluate the integrity of a vehicle's evaporative emission control system, including determining the system's purge capability. The emission tester performs a purge flow test to determine whether fuel vapor stored in the vehicle's evaporative canister and present in the fuel tank is being drawn into the engine for combustion at a minimum amount. The emission tester also performs a pressure test of the vehicle's evaporative canister purge system, which includes the fuel tank and lines. The emission tester can function as a stand-alone unit or as an integrated product with a host computer.

Abstract: An accelerometer is of the type in which a paddle is suspended from a support so that the paddle is displaceable with respect to the support. A suspension arrangement for the paddle includes a pair of compliant beams having longitudinal axes that are substantially orthogonal to each other so that the beams provide compliant isolation to internal stresses while being rigid to external loading forces.

Abstract: A pressure testing device for attachment to an inlet opening of an object to be pressure tested. The device has a sealing head with a bladder. An inlet to the bladder allows it to be inflated and a passage extends through the bladder for pressurising the object. An adjustable coupling is mounted to the stem for attaching the device to the inlet opening and an adjustable guard is mounted to the stem and is movable into engagement against the inlet opening.

Abstract: An apparatus for in situ testing an exhaust system of a conventional internal combustion engine safely, via electrical heater, generating smoke from a smoke-generating fluid contained within a chamber, and then communicating such smoke through the tailpipe components comprising conventional exhaust systems such as tailpipes, clamps, gaskets, hangers, welds, and flanges. By observing smoke emanating from any of the plurality of pipes and associated connections in an exhaust system, any and all leaks therein may be identified and precisely located. The apparatus includes a tapered preferably frustoconically-shaped play which is sealably received into the tailpipe of a vehicle being tested for exhaust leaks.

Abstract: A method and apparatus for detecting faults in a fuel evaporative emission control system, in which the fuel evaporative emission which is admitted from a fuel tank and adsorbed once by a canister is separated from the canister by purge air and sucked into a suction passage of an engine. The fault diagnostic apparatus fluid-tightly closes the fuel tank such that a vacuum is held in the fuel tank, and then detect the presence of a leak in a fuel evaporative emission flow path on the basis of a rate of increase of the pressure in the fuel tank. At the same time, the average value of the pressure in the fuel tank is calculated at regular intervals, and the calculated average value is compared with levels of the pressure in the tank detected within a predetermined period of time, so that the detection of the leak is interrupted depending upon the result of the comparison.

Abstract: A leak diagnosis system for an evaporative emission control system executes a correction process of diagnosis decision value. When the purge control of the evaporative emission control system is not executed, a purging line of the system is set in the atmospheric condition for a predetermined time. A pressure sensor installed in the purging line detects a pressure value V.sub.A0 in the atmospheric condition. A control unit of the leak diagnosis system determines a leak decision value V.sub.P0 on the basis of the atmospheric pressure detection value and an equation V.sub.P0 =V.sub.A0 +.DELTA.V.sub.0 where .DELTA.V.sub.0 is a difference between the output value in the predetermined positive pressure P.sub.0 and the output value V.sub.A0 in the atmospheric pressure condition and is constant. Therefore, it becomes possible to accurately execute the leak diagnosis.

Abstract: An abnormality detecting apparatus for use in a fuel-transpiration preventing mechanism can eliminate effects of changes in operating conditions and variations in equipment to increase the accuracy of abnormality detection. Fuel gas generated in a fuel tank and then absorbed by an absorbing material accommodated in a canister is discharged to an intake pipe by opening and closing a purge control valve. A change in pressure at a negative-pressure holding time after introduction of a negative pressure to the fuel-transpiration preventing mechanism and a change in pressure at an atmosphere-air introduction time after the negative-pressure holding time are calculated and the changes in pressure are used as a basis for determining the existence of an abnormality. As a result, effects of changes in operating conditions and effects of variations in purge control valves and canister closing valves can be eliminated, thus allowing the detection accuracy to be improved.

Abstract: A fuel vapor treating apparatus that collects fuel vapor produced in a fuel tank and treats the vapor without releasing it into the atmosphere. The treating apparatus is provided with a canister that collects the fuel vapor through a vapor line. A vapor control valve provided in the canister adjusts the flow of fuel vapor directed toward the canister from the tank. A purge line connects the canister to an air intake passage of an engine. The fuel collected in the canister is purged into the air intake passage through the purge line. A purge control valve provided in the purge line adjusts the flow rate of the fuel flowing through the purge line. A three-way valve selectively switches the section to which the pressure sensor is connected between the tank side and the canister side. An electronic control unit (ECU) controls the second control valve and the three-way valve.

Abstract: A pressure leakage detector includes a primary gage and a secondary gage selectively connected to each other by means of a valve. The primary gage is connected to an air compressor via a pressure regulator for regulating the pressure supplied thereto and has an outlet port adapted to directly continuously supply the pressure to a large container to detect the leakage of container by means of visual inspection. The secondary gage has an outlet port adapted to connect to a closed system on which a leakage detection is to be carried out. By opening the valve between the two gages to have the closed system reaches a predetermined internal pressured set by the regulator and then closing the valve, a leakage of the closed system may be found by a drop of the pressure reading of the secondary gage. Thereafter, a visual inspection will indicate the exact location of leakage. Thus a precise and correct detection on either a small volume closed system or a large container may be preformed in an quite easy manner.

Abstract: A motion sensor for sensing motion or acceleration of a body, such as the type used in onboard automotive and aerospace safety control system, navigational system or active suspension control system. The motion sensor includes a support frame, a bridge projecting from the support frame, and a proof mass suspended from the support frame by the bridge so as to enable the proof mass to respond to an input force imposed on the motion sensor. The bridge is provided with a strain sensing element that generates an acceleration signal in response to a deflection of the proof mass. The motion sensor further includes a structural feature capable of compensating for mechanically and thermally induced strains imposed on the motion sensor by generating a compensation signal in response to such strains.

Abstract: A fuel canister (18) and fuel tank (14) are purged of any fuel vapors formed therein through a purge valve (22). A method (32) is used to purge the fuel canister (18) and fuel tank (14) in a manner which maintains the stoichiometric balance of fuel and air to be combusted by an internal combustion engine (12). Fuzzy logic is used to correlate the ratio of fuel to air (in mass per unit volume) to a duty cycle in which the purge valve (22) is opened. The fuzzy logic correlation includes the use of triangle functions having substantially similar period which are offset or skewed from each other by fifty percent. This allows each ratio value to be generated by two membership values which provides for a more accurate reading in a less complex manner.

Abstract: The fault diagnostic apparatus of the present invention detects a failure (a leak) of a fuel tank of an engine. In this invention, space above the fuel level in the fuel tank is connected to a canister. The canister contains an adsorbent to adsorb evaporated fuel in the tank to prevent the evaporated fuel from being released to the atmosphere. Valves are provided to the canister to keep the internal pressure of the canister within a predetermined range. A control circuit of the engine employs a pressure sensor to monitor the internal pressure of the fuel tank, and determines whether the fuel tank has failed in accordance with a change in the internal pressure of the fuel tank. Since the change in the fuel level in the fuel tank varies in accordance with the fuel consumption rate, the change in the pressure in the fuel tank also varies in accordance with the fuel consumption rate.

Abstract: An acceleration sensor includes a vibrator and a plurality of pairs of piezoelectric elements which are arranged so as to confront each other through the vibrator. The vibrator is structured so as to be uniformly deformed in accordance with temperature variations. Two pairs of the confronting piezoelectric elements are polarized in opposite directions. An oscillation circuit is connected between the piezoelectric elements and the vibrator to supply the piezoelectric elements with the same driving signals. A first differential circuit is connected to one pair of piezoelectric ceramic elements and a second differential circuit is connected to the other pair of piezoelectric ceramic elements. A third differential circuit is connected to receive the outputs of the first and second differential circuits and provides the output of the acceleration sensor.

Abstract: A device for detecting leakage of fuel vapor including a pressure sensor which is arranged in a fuel vapor conduit connected to the fuel tank. The pressure sensor detects the pressure inside the fuel tank. It is judged that the fuel vapor has not leaked from the fuel tank or the fuel vapor conduit before the engine is stopped based on the pressure inside the fuel tank detected by the pressure sensor and it is judged that the reattachment of the fuel cap has been forgotten when it is judged that the fuel vapor is leaking from the fuel tank when the operation of the engine is restarted after stopping of the engine.

Abstract: An angular speed measuring device includes an oscillator for producing an excitation signal which induces mechanical vibrations in a rotating tuning fork, and an analog processing circuit for processing an electrical detection signal derived from the tuning fork. The analog processing circuit comprises a temperature-independent phase shifter responsive to the excitation signal for producing two signals in quadrature. The quadrature signals are applied to two multipliers which also receive the detection signal. The output signals from the multipliers are dependent on the fixed phase shift .phi. between the excitation signal and the detection signal, which is fixed for a given tuning fork, and on the variable phase shift .psi. which is a function of the rotational speed of the tuning fork, but the multiplier output signals are independent of temperature. After A/D conversion, the multiplier output signals are processed in a microprocessor to determine the angular speed.

Abstract: A portable emissions test apparatus for testing for vapor emitting leaks in a fuel holding system in a vehicle includes a pressurizing system and a pressure-monitoring system. The pressurizing system includes a first pressure regulator configured for connection to a source of pressurized gas for regulating a maximum first pressure in the apparatus downstream of the first pressure regulator, and a first surge protector connected to the first pressure regulator for controlling first surges from the first pressure regulator. The pressurizing system further includes an adjustable second pressure regulator operably connected to the first surge protector for adjustably regulating a second pressure of pressurized gas for operating the apparatus, the second pressure regulator including an adjustment knob positioned in a readily accessible position on the apparatus so that the pressure downstream of the second pressure regulator can be adjusted for changes in ambient atmospheric pressure.

Abstract: Method for setting and/or checking the flow or through-flow in valves, particularly injection valves for internal combustion engines. The injection valve is placed in a measuring device and subject to the action of a fluid. The fluid is passed through the valve at a given volume flow. The pressure set in the measuring device is determined and serves as a measure for the setting and/or checking of the injection valve.

Abstract: A apparatus and method of detecting a leak in an evaporative emissions system measures vapor flow out of the evaporative emissions system while maintaining a zero pressure difference from inside a fuel tank to atmosphere and provides a reference vapor flow variable dependent on the measurement (317). A pressurized vapor and leak flow variable is measured (323) dependent on measured vapor flow out of the evaporative emissions system while maintaining a pressure difference of 10" of water from inside the fuel tank to atmosphere. A leak is indicated (327) if a difference between the reference vapor flow variable and the pressurized vapor and leak flow variable is greater than a predetermined leak flow factor.

Abstract: Piston rings are tested for their effectiveness by removing the cylinder heads of an engine, and sealing one cylinder with a pressure cap. Fluid under pressure is admitted into the cylinder, and time required to dissipate the pressure is monitored. A long time to dissipate the pressure indicates good rings, and a short time indicates bad rings. The several cylinders are sealed an tested one at a time. The pressure cap has a tire valve therein so the conventional air hose can be used to pressurize the cylinder. Preferably, engine oil is placed into the cylinder before the pressure cap is put into place so it is the oil that must move past the piston rings. A hold-down for the pressure cap may be fixed to the engine block using a screw into one of the holes for the cylinder head screws.

Abstract: A fuel vapor treating device that collects fuel vapor produced in a fuel tank and treats the vapor without releasing it into the atmosphere. The treating device is provided with a canister that collects the fuel vapor through a vapor line. A vapor control valve provided in the canister adjusts the flow of fuel vapor directed toward the canister from the tank. A purge line connects the canister to an intake passage of an engine. The fuel collected in the canister is purged into the intake passage through the purge line. A purge control valve provided in the purge line adjusts the flow rate of the fuel flowing through the purge line. A three-way valve selectively switches the section which the pressure sensor is connected to between the tank side and the canister side. An electronic control unit (ECU) controls the purge control valve and the three-way valve.

Abstract: A microwave resonator, useable for acceleration detection, having a cavity in which a resonant frequency F.sub.1 which changes with changes in length of the cavity and with change in crossectional dimensions of the cavity is compensated for changes in crossectional dimensions by forming a second resonant frequency F.sub.2 in the cavity which changes with changes in crossectional dimensions and modifying F.sub.1 by F.sub.2 so as to eliminate the change in F.sub.1 due to changes in crossectional dimensions.

Abstract: A method of pinched line detection for an evaporative emission control system to determine if a pinched line is present within the system includes the steps of pulsing a leak detection pump at a predetermined rate and determining if a last pump period is less than a predetermined possible pinched line period limit. The method also includes the steps of concluding a possible pinched line if the last pump period is not less than the possible pinched line period limit and concluding that there is not a possible pinched line if the last pump period is greater than or equal to the possible pinched line period limit.

Abstract: A method of testing an evaporative emission control system to determine if the evaporative emission control system has reached a predetermined pressure includes the steps of pulsing a leak detection pump at a predetermined rate and determining if a last pump period is greater than or equal to a predetermined test mode period threshold. The method also includes the steps of pressurizing the evaporative emission control system if the last pump period is less than a test mode period threshold and continuing the method if the last pump period is equal to or greater than the test mode period threshold.

Abstract: In an arrangement for testing air-tightness of an electric device having an enclosed housing, and an electric connector fitted into an opening provided in the housing, the electric connector is provided with a communication hole for communicating the interior of the electric device with the exterior, and the communication hole is adapted to close when two halves of the connector are coupled with each other. Thus, the air-tightness of electric device can be conducted when the assembly work is substantially finished whereas the conventional arrangements require an additional assembly work step which could be a potential cause for loss of air tightness. Furthermore, the present invention can be implemented simply by providing a small communication hole in the electric connector and an associated sealing arrangement without requiring any change to the existing device to be tested.

Abstract: A force rebalance accelerometer includes a proof mass suspended by one or more flexures between stationary mounted upper and lower excitation rings. Pick-off capacitance plates formed on opposing sides of the proof mass form capacitance elements whose capacitance varies in response to displacement of the proof mass to provide a displacement signal. The displacement signal is applied to one or more electromagnets, used to force the proof mass back to a null or at-rest position. The drive current applied to the electromagnets thus represents the force or acceleration applied to the accelerometer. The electromagnets include a magnet and a pole piece which forms a magnetic return path. In order to relieve stresses due to thermal expansion, the magnet is spaced apart from the pole piece to enable the bonding area to be constrained to a minimum which, in turn, reduces the overall stress on the accelerometer.

Abstract: A system for hydrostatically testing a cylinder block for an internal combustion engine simulates the gas loads imposed upon the cylinder block when the engine is firing. The system includes an engine cylinder block having multiple cylinders, with pressure conduits extending from a series of hydraulic control valves to each of the operating cylinders such that hydraulic fluid is conducted into the engine cylinders at pressures and frequencies which approximate, if not exceed, the magnitude and frequency of the gas pressure loading imposed upon the operating cylinders when the engine is firing.

Abstract: A resonator microaccelerometer sensitive to accelerations along a first direction is formed from a thin plate whose plane comprises the first direction and a second direction perpendicular to the first direction and that is orthogonal with a third direction. The microaccelerometer comprises a fixed frame; a seismic mass; two hanging legs; and two resonator beams. The hanging legs extend substantially along the second direction, each leg being directed toward the center of gravity of the mass, symmetrically with respect to this center; the resonator beams are parallel, but non collinear, and are symmetrical with respect to the center of gravity of the mass.

Abstract: A venting device comprising connecting lines which are embodied as double-walled that form hollow spaces and whose hollow spaces communicate with one another and with an intake pipe by means of bypass lines. By means of a pressure sensor installed in a bypass line, the vacuum is measured; normally this vacuum must roughly correspond to the vacuum in the intake pipe and if this is the case, it can be concluded that the venting device is functional and tight. If there is a large increase in the vacuum measurement then it is concluded that there is a leak in the venting system. The venting device is particularly intended for use in motor vehicles.

Abstract: The invention concerns a cooling system pressure testing device for the purpose of leak detection. The device has a bladder with a passage extending therethrough. The bladder may be inflated to lock it within an opening in an object to be pressure tested and once inflated fluid may be passed through the passage to pressurize the object being tested.

Abstract: To improve temperature compensation of a piezoelectric element measuring mechanical variables, such as pressure, force, and acceleration, with two or more piezoelectric crystal elements, at least one of the crystal elements differ from the other crystal element(s) either physically or chemically, the positive temperature coefficient of a piezo-coefficient of at least one piezoelectric crystal element compensating the negative temperature coefficient of the other crystal element(s), so that the overall piezoelectric sensitivity of the measuring element will remain essentially constant within a given temperature interval.

Abstract: A force rebalance accelerometer includes a proof mass suspended by one or more flexures between stationary mounted upper and lower excitation rings. Pick-off capacitance plates formed on opposing sides of the proof mass form capacitance elements whose capacitance varies in response to displacement of the proof mass to provide a displacement signal. The displacement signal is applied to one or more electromagnets, used to force the proof mass back to a null or at-rest position. The drive current applied to the electromagnets thus represents the force or acceleration applied to the accelerometer. The electromagnets include a magnet and a pole piece which forms a magnetic return path. In order to relieve stresses due to thermal expansion, the magnet is spaced apart from the pole piece to enable the bonding area to be constrained to a minimum which, in turn, reduces the overall stress on the accelerometer.

Abstract: An acceleration sensor is shown having a substrate (16, 16', 16", 16'") on which a capacitor detect plate (24) and source plate mounting portion (28c) are disposed. An electrically conductive blade member (40, 44) having an attachment portion (40a, 44h), a source plate portion (40i, 44a) and integrally attached beams (40b, 40c; 44b) extending along opposite sides of the blade member is mounted on the substrate by welding the attachment portion to a mounting element (36, 36', 36", 36'") which is closely received in a bore (32, 32', 32", 32'") formed through the substrate at the source plate mounting portion. The mounting element or the bore is formed with a surface suitable for forming an interference fit and for making electrical engagement with a conductive layer received in the bore. The mounting element has one end (36b, 36b', 36b") which extends above the top surface (26, 26") an adjustable selected amount(s) to provide desired spacing between the source plate portion and the detect plate.