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.

Abstract: A gas flow type angular velocity sensor which is capable of reliably sensing an angular velocity while accurately controlling the working gas flow with temperature compensation by using a pair of heat wires as a gas flow sensor without providing any additional gas flow sensor in the sensor body wherein an angular velocity sensing bridge circuit is provided at its current supply source with a temperature compensating circuit connected in series which temperature compensating circuit is composed of a pair of series or parallel connected resistance elements, one of which is a thermosensitive resistance element disposed in a gas path and the other of which is a reference resistance element disposed outside the gas path.

Abstract: An acceleration sensor (10, 10', 10") in which a metal blade member (24) having a source plate portion (24a), attachment portion (24p) and integral resilient beams (24b) extending between the source plate portion and the attachment portion is attached to a pin (22) received in turn in a bore (18a) of a substrate (18). The metal blade member (24) is mounted on the substrate (18) so that the source plate portion is a selected distance from a detect plate (18b) mounted on the substrate. The sensor is disposed in a cylindrical housing (12, 12', 12") which can be directly mounted to a circuit board (50) through terminal pins (18g, 18h, 18i) or can be provided with a threaded fastener (12"d). In one embodiment first and second sensor modules are received in a housing (42) to sense acceleration forces in two perpendicular directions.

Abstract: An apparatus for measuring the ovality, concentricity and runout of an engine valve seat which is comprised of a datum plate, an air gage head, a pot master, a compressed air source, a signal processing device, and a display unit. The compressed air source, signal processing device and the display unit are conventional. One characteristic feature of the invention is the datum plate for limiting the angular displacement of the air gage head during a measurement of an engine valve seat. A second characteristic feature of the invention is that the air gage head "floats" in the air gage body if a measurement is within an established limit for the measurement. A third characteristic feature of the invention is a self-aligning pilot at an end portion of the gage head.

Abstract: The invention is directed to a method of checking the tightness of exhaust valves of an internal combustion engine with the aid of an apparatus. The apparatus includes a device for forming a value LU for the uneven running of the engine and a device for metering air into a region disposed downstream of the exhaust valves as viewed in the flow direction of the exhaust gas. In the method, a first value LU1 is formed for the uneven running without air being supplied in the above-mentioned region and a second value LU2 is formed for uneven running with air being supplied in the above-mentioned region. An exhaust valve is deemed to leak when the first and the second values for the uneven running differ by more than a predetermined amount.

Abstract: A method and a device for determining the load condition of a particle filter (10) used in the exhaust gas system (11) of a diesel engine (12) employed in particular in a motor vehicle, whereina pressure value (.DELTA.P.sub.filter, P.sub.abs.pre-filter or P.sub.rel.pre-filter) and a temperature value (t.sub.m,filter of the exhaust gas volume flow in the particle filter (12) are measured;the engine speed (n) proportional to the volume flow is measured;an actual characterizing value is calculated considering these measurement values; anda comparison between actual characteristic value (IK) and limit characteristic value (GK) is performed for initiating a regeneration process when the difference (DI) is sufficiently small.

Abstract: Measuring devices employing resonant strain gauges, e.g. pressure transducers or accelerometers, are compensated for variation in temperature by employing a secondary resonant microbeam in combination with the primary microbeam of the strain gauge. The secondary microbeam is mounted in cantilever fashion, with one end of the elongate polysilicon beam fixed to a silicon substrate, while the remainder of the beam is free to oscillate relative to the substrate. An oscillating drive voltage is supplied to a drive electrode mounted on the beam and a substantially uniform electrical field is maintained in the region about the beam. The frequency of oscillation is controlled by a piezo resistor formed on the beam and used for detecting instantaneous beam position relative to the substrate. The cantilevered microbeam is free from the effects of residual or induced strain. Therefore, its natural resonant frequency depends upon temperature, as beam modulus of elasticity and density change with temperature.

Abstract: In an arrangement for determining leaks in a tank venting system of a motor vehicle which includes a fuel tank, an adsorption filter in communication with the fuel tank, a venting pipe, a regeneration pipe connecting the adsorption filter to the intake manifold of an internal combustion engine, the venting pipe extends to an area adjacent the filler neck of the fuel tank and a test apparatus is provided with a test pipe having a seal sleeve for placement over the tank filler neck and the end of the venting pipe for applying pressure to the tank venting system by means of pumps disposed in the test apparatus and the test apparatus further includes a pressure sensor for determining the pressure in the tank venting system and a control device for controlling application of pressure to the venting system and for the evaluation of the pressure values determined by the pressure sensor for indicating a leak in the venting system.

Abstract: An evaporative emissions test apparatus is provided including a tester adapted to pressure test a vehicle fuel holding system for vapor emitting leaks. The test apparatus includes an adapter configured to sealingly engage the access port for filling the fuel tank, the adapter being further configured to sealingly receive the vehicle fuel cap so that the vehicle fuel holding system including the fuel cap can be tested as a unit. The tester includes a connector for connecting to the adapter, and further includes a second connector for connecting to a pressure source for pressurizing the fuel holding system and fuel vapor control system to a predetermined pressure. The tester also includes a sensor for sensing the pressure over time, a timer for indicating the passage of a predetermined amount of time, and a display generator and display for indicating if the pressure in the atmosphere is acceptable after passage of the predetermined amount of time.

Abstract: A pneumatic apparatus to test an engine oil pump of the type designed to be driven by an end of the engine crankshaft. On a test stand, the pump is rotated by a driving mechanism while airflow is generated by the pump itself or while pressurized air is introduced. Air flow characteristics are measured and analyzed to determine acceptability of the pump.

Abstract: A leak detection assembly for an evaporative emission control system in an automotive vehicle including a fuel tank, a canister for collecting volatile fuel vapors from the fuel tank, a purge valve disposed between the canister and an intake manifold of an engine operative to allow flow of the fuel vapors from the canister to the intake manifold, a vacuum actuated pump in communication with the canister, and a vent control valve operative to selectively allow and prevent communication between the canister and an atmospheric vent of the vacuum actuated pump, the leak detection assembly including a three-port solenoid fluidly connected to the intake manifold and a second atmospheric vent, and a vacuum line fluidly connecting the three-port solenoid to the vent control valve, the three-port solenoid selectively communicating with the intake manifold to allow a vacuum in the vacuum line during a first operating mode to close the vent control valve and selectively communicating with the second atmospheric vent dur

Abstract: The existence of an unacceptable vapor leak can be determined by monitoring the pressure within a fuel system of an internal combustion engine. Once the engine is switched off, a period is timed to allow pressure variations due to movement of the fuel to subside to an acceptable level. The fuel system is closed and a first rate of pressure increase is determined by measuring a first time taken for the pressure to rise by a predetermined amount. A leak of a predetermined size is then introduced and a second rate of pressure increase is determined by measuring a second time taken for the pressure to rise by a predetermined amount. The first and second times are then compared to detect whether or not an unacceptable leak exists.

Abstract: A method for detecting trapped air in an engine cooling system includes the steps of delivering a volume of test air pressure under pressure to the radiator of the cooling system, measuring the volume of test air delivered, measuring the pressure of test air delivered, and calculating the volume of trapped air in the cooling system using Boyle's law and the measured volume and pressure of test air. A device for carrying out the method comprises a pump for delivering test air to the radiator, a motor for driving the pump, a pressure gauge or pressure switch for sensing the pressure of test air delivered, and means for determining the volume of test air delivered.

Abstract: A temperature and static pressure compensated differential pressure sensor includes a semiconductor substrate in which a flexible, pressure responsive diaphragm is formed. A pressure responsive resonant microbeam is fabricated at the diaphragm periphery. For temperature compensation, a secondary resonant microbeam sensor is fabricated on the substrate at a peripheral location beyond the point of substrate attachment to a pressure tube or other support. For static pressure compensation, another secondary resonant microbeam can be positioned remote from the diaphragm and at a location of maximum substrate response to static pressure. A further resonant microbeam can be mounted at the diaphragm center to augment the signal due to diaphragm deflections. Also disclosed is an accelerometer including a proof mass, a rigid rim surrounding the proof mass, and a series of narrow, flexible bridges supporting the proof mass relative to the rim.

Abstract: An apparatus and method for the non-intrusive testing of evaporative fuel vapor systems of motor vehicles. A portable pressure control and monitoring unit is inserted into the fuel filler neck of a vehicle. The vapor vent line, leading from the fuel tank to the charcoal canister of the evaporative system, is temporarily clamped off. Pressurized gas is introduced into the unit from an operator's console, expanding a ring bladder and sealing an annular volume between the unit and the filler neck. Gas is then passed through the unit into the contained volume of the evaporative system. After the neck cap is replaced, an automatic timer deflates the ring bladder, charging the remaining volume of the evaporative system. Pressure decay data is collected and stored in the unit's digital storage device. Initially, this data is used in a pass/fail determination made by a microprocessor in the unit. Later, the data is downloaded into a separate computer for archival purposes.

Abstract: A leak diagnosis system which diagnoses a leak condition of an evaporative emission control system for an internal combustion engine. The leak diagnosis system detects a changing speed of a pressure in the evaporative emission control system for plural times during when the evaporative emission control system is put into a negative pressure condition by the negative pressure of the engine and is then closed by a purge-cut valve. The leak diagnosis system diagnoses a leak condition of the evaporative emission control system according to the detected plural pressure changing speeds while taking a fuel condition in the evaporative emission control system into consideration on the basis of the detected plural pressure changing speeds. Accordingly, the leak condition in the evaporative emission control system is accurately diagnosed without being effected by the fuel condition.

Abstract: The invention relates to a method for monitoring the switching process of a coupling device for inlet or outlet valves. The valve is actuated by two transmission elements which can be coupled to one another by means of a coupling device and are driven by two cams with different cam elevations. The coupling device consists of a bolt which is guided, so as to be capable of moving by means of a pressure medium, in two bores which are arranged on the transmission elements and are placed flush. According to the invention, an evaluation device is provided with which it is monitored whether the bolt reaches the coupled position. For this purpose, the evaluation device detects the signal of a pressure sensor arranged in the control pressure line. In this process, whether the coupled position has been reached can be detected by the occurrence of a pressure surge in the control pressure line which is caused by the striking of the bolt against a stop.

Abstract: A thermally stable solenoid including a heater coil and an inductive coil wound around the same axis. The current in the heater coil is controlled by the current in the inductive coil through a control circuit. The heater coil is energized in such a way as to ensure that the heat generated by both coils is constant throughout the required range of operation.

Abstract: A combined transducer that measures force or displacement and temperature utilizes a pair of vibrating tines to provide a simultaneous output representative of temperature and force or displacement whereby the sum or average of the vibrating frequencies of the two tines is representative of temperature and the difference is representative of force or displacement.

Abstract: A method of measuring the volume and the velocity of fluid flow through individual ports or combination of ports of a ported cylinder as defined by the cut away of an isolation tube, and utilizing a pitot tube coupled with a pressure differential gage to measure flow velocity while imposing fluid pressure at a predetermined pressure, and at a predetermined inlet opening and a measuring device for comparing inlet pressures to determine differences in flow volume, and an apparatus for carrying out the method.

Abstract: An exhaust filter backpressure indicator includes a sensor for measuring the backpressure and the exhaust system. The sensor sends a signal which is processed for indicating that an exhaust filter element is filled. The indicator includes a timer so that a signal corresponding to pressure must be maintained for a predetermined period of time before the filled element is indicated. The apparatus may also include high and low frequency discriminators to process signals within predetermined signal frequency ranges corresponding to engine operating speeds. Therefore, depending on the operation of the vehicle, the element will be indicated as being filled at either high engine speed operation or low engine speed operation.

Abstract: The vacuum tester has a housing which is small enough to be held in one hand in which is contained a small vacuum pump, an activator switch and a vacuum gauge. A non-return flap valve, or check valve, is disposed between the vacuum pump and the vacuum gauge so that the vacuum within the chamber under test is not lost once the vacuum pump has been turned off. A connector with a vacuum hose extending therefrom is provided to apply the vacuum to the chamber. Interchangeable adapters can be attached at the end of the vacuum hose to provide a seal with the opening in the chamber. Detection and quantization of leaks in closed systems is provided by observing the leak-back rate on the vacuum gauge once the vacuum pump has been turned off.

Abstract: A signal processor (5) is coupled to a detector (6) for detecting a physical quantity. The signal processor has a zero adjustment memory (14) and a sensitivity adjustment memory (16). The zero adjustment memory and the sensitivity adjustment memory have a number of switches (20, 20A, 20', 20"), respectively. These switches are changed over digitally using a zener zapping method or a polysilicon fuse method at each switch to adjust the characteristics of the detector.

Abstract: A drift canceling apparatus has an angular velocity detecting sensor with a detection output having temperature/time drift, the output being supplied to an object to be controlled. A reference signal extraction circuit extracts a reference signal from the detection output. The reference signal extraction circuit includes a differentiation circuit for differentiating the detection output of the angular velocity detecting sensor, a comparison circuit for comparing the detection output of the angular velocity detecting sensor with the output signal of the differentiation circuit to produce a comparison circuit output signal, a selection circuit for selecting only an output in a required normal operation region from the comparison circuit output signal, and a sample hold circuit for sample-holding the detection output of the angular velocity detecting sensor in response to the output of the selection circuit to produce a sample hold signal used as the reference signal.

Abstract: Apparatus for monitoring suction leakage of external air into the exhaust gas path of an internal combustion engine during intermittent reduced pressure phases of engine running, includes two oxygen concentration sensing lambda probes arranged at a distance from one another along the path. The probes issue signals indicative of such oxygen concentration which are fed to a control device, such that an error signal is generated on deviation of the two probe signals from one another as caused by suction entry of external air into the path solely during a reduced pressure phase.

Abstract: An accelerometer unit has a capacitor detect plate and a source place connector preferably defined respectively inside and outside a groove in one surface of a ceramic substrate. A flat metal member has an attachment portion secured in electrically conductive relation to the connector, has a source plate portion spaced over the detect plate to form a capacitor, and has integral resilient beams extending from the attachment portion to support the source plate portion spaced from the detect plate to be movable relative to the detect plate in response to acceleration force to provide an electrical signal. Preferably glass rods between the attachment member portion and source place connector facilitate the spacing.

Abstract: A vibratory gyroscope includes a vibrator. The vibrator includes a triangular prism-shaped vibrating body. On three side faces of the vibrating body, piezoelectric elements are formed respectively. Supporting members are fixed to ridge-line portions in the vicinity of nodal points of the vibrating body. The supporting members are formed into a multi-layer structure. An elastic material having a large strength is used as inner portions of the supporting members, and a material having a good solderability is used as outer portions of the supporting members. Under the vibrator, a supporting plate is provided as a shield material. Furthermore, a work cover is provided on the side of and above the vibrator as a shield material. The supporting plate and the work cover are formed by a magnetic material such as iron, nickel, stainless steel or the like. In the vicinity of the supporting members, protective members are provided.

Abstract: An accelerometer device particularly adapted for use in automotive safety air bag applications comprises an electrically insulating substrate having electrically conducting circuit paths, signal conditioning circuit components, and an accelerometer unit mounted thereon, the substrate being fixed in position on three pins within a housing. The accelerometer comprises a silicon mass movable in a silicon body relative to an integral silicon support to provide strain in the silicon body in response to acceleration and has piezoresistive sensors formed in the silicon body to be responsive to that strain to provide an electrical signal corresponding to the acceleration.

Abstract: A method and apparatus for the testing of vehicle fuel tank caps includes the mounting of a cap to be tested upon a mating socket. The socket/cap combination define a sealed chamber which can be pressurized and/or evacuated in a controlled manner. A pressure transducer monitors the pressure within the chamber. The monitored pressure is compared to reference values to determine cap integrity. The apparatus may be incorporated into a vehicle testing system using microprocessor control and having a database of vehicle, cap and performance data.

Abstract: An accelerometer has a capacitor detect plate defined on an electrically insulating substrate adjacent a capacitor source plate connector and has circuit paths on the substrate connected to the detect plate and source plate connector. A resilient metal plate has an attachment portion secured to the source plate connector, has a capacitor source plate portion, has integral first beam elements extending away from the attachment portion and has a second beam element extending from the first beam elements back toward the attachment portion to dispose the capacitor source plate in spaced relation to the detect plate to form a capacitor having selected initial capacitance. The capacitor source plate member portion is movable relative to the detect plate to modify device capacitance in response to acceleration. Electronic components are mounted on the substrate connected to the circuit paths to provide an output signal corresponding to the acceleration.

Abstract: An angular rate sensor for a vehicle navigation system stores an environmental temperature and a related null voltage each time the vehicle stops. The pairs of data points are stored in a non-volatile look-up table for use during vehicle motion. During vehicle motion, the environmental temperature is measured, and a null voltage is selected from the look-up table corresponding to the measured temperature. The null voltage is used to correct drift offset. Interpolation is used when data keyed to the measured temperature cannot be found in the look-up table.

Abstract: Accelerometer having a frame, a proofmass, one or more force sensitive transducers, and a strut interconnecting the transducers with the proofmass and the frame so that forces are applied to the transducers in accordance with movement of the proofmass along the sensitive axis. The transducers and the strut have similar thermal expansion properties and are arranged in such manner that they can expand together with changes in temperature independently of the frame and the proofmass without imposing any significant strain on the transducers. In certain disclosed embodiments, the transducers are formed as a unitary planar structure from a single piece of crystalline quartz material, and the strut is formed of the same material.

Abstract: A stress isolation technique for an accelerometer of the type that has a reed that includes a paddle, a support, and flexures connecting the paddle to an area of the support. The support includes one or more mounting pads through which the reed is mounted. The area of the support adjacent to the flexures is divided into first and second portions, such that the flexures are connected to the first portion and such that the mounting pads are positioned solely on the second portion. The flexures are therefore isolated from stress coupled into the reed through the mounting pads.

Abstract: A cylinder head flow test apparatus and method for testing cylinder heads for blockages in water passages wherein blockages in the water passages contained in the cylinder head can be detected by blowing low pressure air at a high velocity into the water passages and measuring the resulting back pressure produced by restrictions within the water passages. The disclosed method and apparatus include means for selectively testing the water passages in a cylinder head and for comparing the back pressure readings obtained from the test to back pressure readings previously obtained from a cylinder head whose water passages are known to have no blockages. An apparatus and method also disclosed for simultaneously testing all water passages in a cylinder head for blockages.

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: An integrated accelerometer includes features for minimizing the effects of foreseeable operational stresses. The accelerometer is of a type that includes a planar support base having an internal aperture for accommodating a hinged strut and limit stops for minimizing the travel of the shadow paddle portion of the strut. The limit stops are fabricated of material of suitable spring constant to provide an appropriate degree of "give" without degrading instrument performance or accuracy. Two-piece arrangements sandwich the hinges, thereby limiting flexure to an acceptable range. The predictable mechanical stresses resulting, for example, from thermal coefficient mismatches between the materials of the torquer coil and the strut are minimized by the use of a spacer intermediate the base and the coil.

Abstract: An accelerometer has a capacitor detect plate defined on an electrically insulating substrate adjacent a capacitor source plate connector and has circuit paths on the substrate connected to the detect plate and source plate connector. A resilient metal plate has an attachment portion secured to the source plate connector, has a capacitor source plate portion, has integral first beam elements extending away from the attachment portion and has a second beam element extending from the first beam elements back toward the attachment portion to dispose the capacitor source plate in spaced relation to the detect plate to form a capacitor having selected initial capacitance. The capacitor source plate member portion is movable relative to the detect plate to modify device capacitance in response to acceleration. Electronic components are mounted on the substrate connected to the circuit paths to provide an output signal corresponding to the acceleration.

Abstract: An accelerometer device particularly adapted for use in automotive safety air bag applications comprises an electrically insulating substrate having electrically conducting circuit paths, signal conditioning circuit components, and an accelerometer unit mounted thereon, the substrate being fixed in position on three pins within a housing. The accelerometer comprises a silicon mass movable in a silicon body relative to an integral silicon support to provide strain in the silicon body in response to acceleration and has piezoresistive sensors formed in the silicon body to be responsive to that strain to provide an electrical signal corresponding to the acceleration.

Abstract: An acceleration sensor includes a tubular bobbin only one end of which is fixed to a body whereas the other end is movable relative to the body axially of the bobbin. Supported on the body are magnets for attracting a magnetic member, mounted within the bobbin, to a reference position. A detection member is mounted around the bobbin so as to detect a displacement of the magnetic member from the reference position. A gel can be filled in a receiving space of the body in which the bobbin is received. The body can be of a tubular shape, with covers fixedly secured respectively to opposite ends of the body, in which case opposite ends of the bobbin are disposed in opposed, spaced relation to inner sides of the covers, respectively. The body can be received in a housing, and a circuit board can be received in an auxiliary receiving space in the housing.

Abstract: A temperature compensation system for a force balance accelerometer is disposed within a feedback loop. A series resistor (82) is connected in series with torque coils (30,80). Connected in parallel with the torque coils and the series resistor (82) is a parallel resistor (84) having a positive resistive temperature coefficient. Series resistor (82) and parallel resistor (84) are placed in close thermal communication with torque coil (30) and a magnetic circuit that includes stators (10 and 12) and permanent magnets (14). As the temperature of the accelerometer increases, less current flows through parallel resistor (84) and more current flows through the torque coil (30), thereby compensating for a reduced torque constant of torque coil that decreases with temperature, yet, enabling the resulting output current, I.sub.o, to remain constant (for a given acceleration).

Abstract: The mounting system of the present invention is adapted to support a precision transducer (14) in spaced alignment with a supporting case (12). The mounting system comprises a plurality of mounting elements (30), each mounting element having one end (34), an opposite end (32) and a resilient intermediate portion (36). One end is adapted to be connected to the transducer, and the opposite end is adapted to be connected to the case. Adjacent mounting elements are joined to one another by bridge sections (38) to form a continuous mounting ring (16) and to define a plurality of gaps (56). At least the end connected to the transducer and bridge sections is composed of a substance that has a coefficient of thermal expansion approximately equal to the coefficient of thermal expansion of the transducer. Each intermediate portion is configured to provide a low resistance to relative movement between the transducer and case in a radial direction, and a high resistance to relative movement in other directions.

Abstract: A method and apparatus for testing an engine cylinder head for leaks regardless of whether the cylinder head is attached to an engine block. The cylinder head has a fuel injector aperture extending from a first side to a second side thereof, has a coolant passageway communicating with the fuel injector apertures between the first and second sides of the cylinder head, and has a sleeve in the fuel injector aperture to separate the fuel injector aperture from the coolant passageway. An air-tight seal is formed in the fuel injector aperture between the coolant passageway and the first side of the cylinder head. Another air-tight seal is formed in the fuel injector aperture between the coolant passageway and the second side of the cylinder head. The fuel injector aperture is then pressurized between the air-tight seals thereof. The pressure of the fuel injector aperture between the air-tight seals is then monitored over a period of time.

Abstract: A universal pressurizing adaptor for pressurizing an engine cooling system in leak testing is connectible to the cooling system of an automotive vehicle. The adaptor includes a cylindrical body having an adaptor neck located at one end, and an overflow vent and a flexible adaptor hose attached to an outlet neck located at the other end of the adaptor. The adaptor neck is connectible to a conventional pressure cap of a pressurizing pump and the adaptor hose is connectible to the overflow vent joined to the filler neck of the radiator of the automotive vehicle.

Abstract: The pressure-testing apparatus comprises a manifold having a pair of conduits extending therefrom and being substantially parallel. Quick connectors at the free ends of the conduits have receptacles the axes of which are substantially parallel. A pair of adapters are respectively attached to the fittings of a broken coupler in a vehicle. The quick connectors are respectively applied to the adapter elements. The apparatus also comprises a pressure gauge on the manifold and/or means on the manifold for connection to a gauge.

Abstract: Proofmass assembly for an accelerometer having transducers fabricated of crystalline quartz and other components fabricated of fused quartz. The assembly includes a main support, a frame pivotally connected to the support for pendulous movement about a hinge axis such that the frame moves with a component of motion along the sensing axis of the accelerometer, a proofmass connected to the frame for movement about a compensation axis spaced from and generally parallel to the hinge axis, and a pair of transducers connected between the proofmass and the support for sensing forces produced by acceleration of the proofmass along the sensing axis. Differences in thermal expansion between the transducers and the fused quartz components are taken up by rotation of the proofmass about the compensation axis, and the two parallel axes permit translational motion of the proofmass in response to acceleration along the sensing axis without rotation of the proofmass relative to the support.

Abstract: An angular velocity sensor includes a pair of vibratory piezoelectric detecting elements defining detecting planes which are disposed in symmetry about a plane containing the sense axis and out of right-angled orientation with respect to this plane. The detecting elements thus arranged assume a widely spread or flattened V-shaped configuration as viewed from above. Output signals of opposite polarities received from the respective detecting elements are weighted respectively and added together so as to cancel out unwanted leak component signals. Thus, leak component signals resulting from assembling tolerances can be canceled. In this instance, if the characteristics of two sensor elements each including one of the detecting elements are fully equivalent, a leak component signal dependent on a disturbing inertial force can simultaneously be canceled out.

Abstract: An improved technique for mounting a coil to a paddle in a force rebalance accelerometer so as to provide relief from temperature induced strains without increasing the mass of the proof mass. The coil is mounted to the paddle at a plurality of mounting sites on the paddle, at least one of which is connected to the paddle by suspension means compliant for movement in the plane of the paddle. In a preferred arrangement, three mounting sites are used, two of which are moveable towards and away from the third, fixed mounting site.

Abstract: A pair of torquer magnets each comprising a cup-shaped yoke is provided with a disk-like permanent magnet and a pole piece. A through-hole provided through the center of the torquer magnet and a spool member made of a magnetic compensating metal is inserted into and fixed in the through-hole. The spool is shaped to have a central portion intermediate its end of a substantially smaller diameter.

Abstract: An apparatus for in situ testing of an internal combustion engine for vacuum leaks is provided. In accordance with the present invention, smoke is generated from a suitable smoke-generating fluid in chamber means, and then sealably communicated through conduit means to the intake manifold of a vacuum system in an internal combustion engine. By visibly observing smoke exiting from any of the hoses, flanges and gaskets contained within a vacuum system, leaks therein may be readily located.

Abstract: A transducer having compensation for a deflection due to an applied stress. The transducer includes a support ring (32) having a proof mass (34) cantilevered on a pair of flexures (38) between the magnets (26,28) of a stator in which the transducer is mounted. Deflection of the support ring due to an imbalanced applied force is compensated by either moving the pads (30) used to mount the support ring, moving the centroid of capacitance (42) of the proof mass, or by modifying the support ring to provide a pair of moment arms (152), each approach insuring that an axis of deflection (102,130) of the support ring is coaligned with the centroid of capacitance, thereby minimizing a bias error in the transducer output.