Abstract: A cooling system for a communication station for cooling a casing of the communication relay station, accommodating communication equipments including heat components, by a boiling-type cooler in a natural circulation refrigerating circuit and an evaporator in a forced circulation refrigerating circuit, activated by a compressor comprising: a common airflow path having a heated air intake port for taking a heated air in the casing; and a common fan for sending an air to the boiling-type cooler and the evaporator, wherein the boiling-type cooler, the evaporator, and the common fan are built in a common airflow path.

Abstract: A combined cooling and heating system having a simple design of a combined cooling and heat pump plant, especially for the heating and cooling of the passenger cells of motor vehicles. The concept of the invention is that the combined cooling and heat pump plant has a decompression device that fulfills the functions of a decompression device and a mode switch. The advantage of the invention is that dependent on the direction of flow, and thus the operational mode of the device, the decompression function and the blocking function, or the pressure relief function are realised by one component, the decompression device.

Abstract: A design of a compact solar air conditioning system especially suited for tropical climates includes an air-cooled single-effect absorption machine driven by an array of high performance flat-plate collectors along with a thermal storage tank. The absorption machine uses lithium-bromide as a refrigerant and a water-based absorption fluid. The operation of the compact solar air conditioning system is determined by an optimal control strategy.

Abstract: An automobile air conditioner having a charging device for charging a power source capacitor preliminarily before driving a motor-driven compressor, which comprises a discharge circuit for discharging the electric charge in the capacitor through a power feeding device, and a controller for controlling the discharge by the discharge circuit. Further by comprising a cut-off detecting circuit for detecting when the battery is cut off, it is discharged automatically. Moreover, the voltage of the battery is converted, and supplied as a power source for the controller.

Abstract: A food display cooler for display of packaged and non-packaged food products for self-service by customers. The cooler simultaneously provides a cooled frosted display platform and a blanket of cooled air above the display platform and over the food products. The display platform is pivotally mounted to a pan underlying the display platform. The display platform has a first cooling coil attached directly to the bottom surface of the display platform and a second cooling coil and a fan is connected to the display platform such that the cooling coil pivots with the display platform when it is pivoted to the open position. A refrigeration unit is connected in fluid flow communication with the cooling coil, and is connected to the exterior surface of the pan.

Abstract: A refrigerated showcase has a front opening through which a consumer can view and access foodstuffs on display. The foodstuffs are cooled by coolant air introduced through a slanted, perforated, interior panel located near a rear wall of the showcase. An air curtain directed downwardly at the front opening minimizes coolant air loss through the opening. Lips are applied and extended from the edges of vertical sides of the access opening to reduce the loss of coolant air through the air curtain. Thus, relative flows of coolant air and the air curtain are maintained inside the showcase.

Abstract: An ice maker is provided including a refrigeration system for cooling an ice forming surface below the freezing temperature of water. The ice maker further includes a water supply inlet, a water collecting device connected to receive a supply of water from the water supply inlet and arranged to receive a flow of water from the ice forming surface, a recirculating pump having an inlet connected to the water collecting device, a recirculating passage connected at a first end to an outlet of the recirculating pump and arranged to direct water toward the ice making surface, and a magnetic field generating device positioned along a length of the recirculating passage.

Abstract: A transport assembly for a cryogenic processor having an elongated housing forming a channel for the delivery of a frozen product from an intake end to a discharge end. The system includes a screw-type conveyor disposed within the elongated housing for movement of the frozen product from the intake end to the discharge end. An indirect drive motor assembly is provided and configured to rotate the screw-type conveyor. A nozzle assembly is provided for attachment to the transport assembly at the discharge end, the nozzle assembly being configured to inject wash and rinse solutions into the elongated housing. In addition, a drain line is disposed near the intake end of the elongated housing. The drain line facilitates a clean in place procedure.

Abstract: A cycle-side system (20) is formed by duct connecting a compressor (21), a heat exchanger (30), a demoisturizer (22), and an expansion device (23) in that order. The compressor (21) draws in room air and supply air for ventilation and compresses the same. The compressed air exchanges heat with exhaust air for ventilation in the heat exchanger (30), thereby being cooled. Water vapor in the cooled, compressed air is removed in the demoisturizer (22). The demoisturizer (22) is provided with a separation membrane and separates water vapor in the compressed air without the occurrence of condensation. Thereafter, the compressed air is expanded in the expansion device (23) to change into low-temperature air. The low-temperature air is supplied into a room. On the other hand, the heat exchanger (30) is fed exhaust air cooled in a humidifying cooler (41).

Abstract: A vessel for use in a refrigeration system. The vessel includes a vessel body and at least one end wall for closing the vessel body, the end wall having a threaded receptacle. The threaded receptacle is configured to accept a threaded fitting and the threaded receptacle includes: an annular sealing surface for engaging a corresponding surface of the fitting, the sealing surface formed on a first side of the end wall; and a threaded surface defined by an inside wall of an annular protrusion, the annular protrusion having a longitudinal axis disposed generally perpendicular to the sealing surface, and wherein the protrusion extends longitudinally from a second side of the end wall toward an interior of the vessel body.

Abstract: A high pressure gas cooler for a motor-vehicle air-conditioning system, the refrigerant circuit having, in the flow direction of the refrigerant, a compressor, the gas cooler, an inner heat exchanger exchanging heat between the high-pressure and low-pressure sides, a throttle device, an evaporator and a manifold on the low-pressure side, which communicates via the low-pressure side of the inner heat exchanger with the intake side of the compressor. The gas cooler is combined with the inner heat exchanger and/or the manifold on the low-pressure side to form a single unit.

Abstract: The invention relates to a process of manufacturing a pressurized multi-component liquid from a pressurized, multi-component stream, such as natural gas, which contains C5+ components and at least one component of C1, C2, C3, or C4. The process selectively removes from the multi-component stream one or more of the C5+ components that would be expected to crystallize at the selected temperature and pressure of the pressurized multi-component liquid product and leaves in the multi-component stream at least one C5+ component. The multi-component stream is then liquefied to produce a pressurized liquid substantially free of crystallized C5+ components. The removal of the C5+ components can be by selective fractionation or crystallization.

Abstract: A process and apparatus for the production of low pressure gaseous oxygen (“GOX”) in which compressed and purified feed air (1) is cooled and at least partially condensed in heat exchange means (E1) having a warm end and a cold end and the cooled and at least partially condensed feed air (2) is then distilled in a cryogenic distillation column system (C1, C2). A liquid oxygen (“LOX”) product stream (8) is removed from the column system (C1, C2) and vaporized and warmed by heat exchange (E1) to produce GOX. LOX refrigerant (10) from an external source is used to provide a portion of the refrigeration duty required for the cooling and at least partial condensation of the feed air stream (1).

Abstract: A combination earrings and nape chain and method therefor comprising a set of earrings and a chain coupled thereto. One embodiment of the combination earrings and nape chain comprises a chain dimensioned to restrict the movement of hair proximate the nape. Another embodiment of the combination earrings and nape chain comprises a chain dimensioned to adorn the nape. In all embodiments, the length of the chain varies in proportion to the size of the nape, the amount and type of hair, and the personal preference of the wearer.

Abstract: A glass material (4) is placed in a forming die including a pair of upper and lower dies (1, 2) and a control member (3) for controlling the space between the upper and the lower die, and then heated, softened, and molded by pressure into a glass substrate in the shape of a parallel plate. The amount of thermal contraction of the control member is smaller than that of the glass material. Therefore, the glass substrate is released from the die when cooled after molding. The present invention can provide a glass substrate that is excellent in smoothness and form accuracy of the surface, and that is suitable for recording media such as magnetic disks that are inexpensive and suitable for mass production.

Abstract: An I.S. machine has a blankmold which is open at the top and includes inner and outer annular top sealing surfaces. Associated with the blankmold is a baffle including a body having a cup shaped portion closed with a vertical cylindrical bore open at the bottom, an annular bottom sealing surface for sealingly engaging the blankmold outer annular top sealing surface, and a top having a hole. A tubular sleeve communicates with the hole and extends vertically upwardly from the top of the body. A piston has a cylindrical head including a top surface, a cylindrical sealing surface and an annular bottom sealing surface having a plurality of radial notch means across the bottom thereof. A tubular rod extends vertically upwardly from the top surface for slidable displacement in the tubular sleeve, and a collar is secured to the top of the rod.

Abstract: An openwork tubular knitted fabric formed of closely knitted, fine gauge yarns formed into knitted loops utilizing at least 11 needles per inch and having at least 25 courses per inch. The fabric is formed by using needles having a hook formed in a top end of a needle shank and a latch pivotally mounted on the needle shank below the hook for opening and closing the hook, and including a deflector for deflecting a loop of yarn being formed by a needle into the vertical plane of an adjacent needle, and a needle cam mounted for reciprocal movement between first and second vertically-spaced positions. The fabric is characterized by having a fine, dense background with small, closely-spaced holes which enable a highly-detailed pattern suitable for a wide range of undergarments and hosiery products. The density and fineness of the fabric provides both the comfort and lack of show through necessary for many garments of this type.

Abstract: A drum type washing machine includes an outer cabinet (1), a water tub (3) disposed in the cabinet (1), a rotating tub (10) disposed in the water tub (3) so as to be inclined rearwardly downward, and an electric motor (17) of the outer rotor type mounted on a rear wall (26) of the water tub (3) for directly driving the rotating tub (10).

Abstract: A lock has a first steel plate having a first through hole defined to correspond to the core of the body, a circular cap movably received in the first through hole and having a slit defined to correspond to the keyhole of the core. A second steel plate is securely attached to the first steel plate and has a second through hole corresponding to the first through hole and bores corresponding to the holes of the first steel plate. A protection cap is securely attached to a bottom of the second steel plate and a distal edge of the protection cap is securely connected to an outer face of the body. The protection cap has an opening defined to correspond to the second through hole.

Abstract: A lock which includes a bolt which is movable between a locked position and an unlocked position against the action of a biassing element such as a spring, first retaining element which is engaged with the bolt and which retains the bolt in the locked position and which is movable between a first position at which the first retaining element restrains the bolt from being moved from the locked position to the unlocked position and a second position at which the first retaining element restrains the bolt from being moved from the unlocked position to the locked position, remotely actuable release element, which when actuated, causes movement of the first retaining element from the first position to the second position, and handle element for moving the bolt from the locked position to the unlocked position when the first retaining element is disengaged from the bolt.

Abstract: A steering wheel lock utilizes a motor-driven spindle which drives a locking nut to control a detent disk which has pin-like projections engaged in camming tracks which guide the detent disk linearly and angularly. The detent disk in turn controls a locking pin which can engage the steering wheel shaft.

Abstract: An E-series skid steer lock having a mounting plate, a base plate and a bar member. The base plate is positioned on the safety cage inside a skid loader cab and is bolted to a mounting plate one the safety cage outside the skid loader cage. The bar member is used to restrict the motion of the skid loaders drive control lever by attaching the bar member to the base plate. Once the bar member is attached to the base plate it is locked in position with a locking mechanism.

Abstract: A push-button steering wheel lock for attachment to an automobile steering wheel is provided having a housing and a push-button assembly disposed in the housing. The assembly is positioned in either a locked position for securing the steering wheel lock to the steering wheel or an unlocked position. In the locked position, the push-button lock assembly engages a rod slideably disposed in the housing to prevent movement of the rod with respect to the housing. The push-button assembly also includes two levers, one each on either side of the assembly to engage two surfaces within the housing to retain the push-button assembly in the locked position and also to retain the push-button assembly in the housing.

Abstract: Retractable hitching post for bicycles having a casing which is mounted in the ground, a post which is telescopically mounted in the casing for movement between a retracted position in which the post is below ground level and an extended position in which a substantial portion of the post is above ground level. The post can be secured in the extended position, and a bicycle can be locked to the post. In some disclosed embodiments, the post is cushioned by air damping as it returns to its retracted position.

Abstract: A monitoring device for a protected area of a machinery installation, the area being accessible through at least one access opening which can be closed off by an element, such as a door, shutter, or the like, which is movable between an open position and a closed position. The monitoring device being arranged adjacent to the movable element and comprising a safety switch having a housing, an evaluation device, a movable element positionable between a closed and an open position, a coded release mechanism located on the movable element, and a read head for reading the coded release mechanism when the movable element is in the closed position. The safety switch being further provided with an actuator bearing a release mechanism, and which, in a locking position in the housing, locks the movable element in its closed position. The housing having a receiving space for the actuator such that the release mechanism is located adjacent to the read head when the actuator is in the locking position in the housing.

Abstract: A padlock includes: a lock body; a shackle operatively locked in or unlocked from the lock body; a key-operated locking device formed in the lock body for operatively unlocking the shackle for unlocking the padlock by using a key, and a combination locking device juxtapositionally formed in the lock body for operatively unlocking the shackle for unlocking the padlock merely by dialing the combination to an unlocking number.

Abstract: The inventive device comprises a seat which is situated in the device housing and which is provided for the insertion of an identification provider. A holding element located inside the seat engages with a lateral indentation of the identification provider. The opening of the seat is normally closed by a spring-loaded cover element. In order to create a functionally reliable and economic design, the invention provides that the cover element is configured as a pivotal flap which can pivot from the identification provider out of an outwardly pivoted position covering the opening of the seat and into an inwardly pivoted position inside the seat. A projection is provided on the outer side of the flap and functions as a holding element for the identification provider. A recess is arranged next to the seat for the inward pivotal movement of the flap.

Abstract: The numeral control device for a bending machine comprises means for inputting, as input data, a desired bend angle and bending conditions or criteria, means for storing groups of data, each containing bending conditions, a bend angle and a penetration depth, and means for searching whether the input data is stored in the memory means, in the same group of data. Moreover, means are provided for transmitting a signal representative of a penetration depth included in the group of data stored in the memory means, or for transmitting a signal for controlling the bending machine according to this penetration depth.

Abstract: A method for manufacturing an air-gap-insulated exhaust pipe having a branch stub, as well as an exhaust pipe produced according to such a method and a tool for forming such an exhaust pipe. Two tubes are inserted into one another to form a double tube. The double tube is placed in a first internal high-pressure shaping tool, and exposed to internal high pressure fluid such that it expands to match the contours of the engraving of the first shaping tool, and a double-walled branch stub is blown out of the double tube. The partially formed double tube is then placed in a second internal high-pressure shaping tool, with the double tube being surrounded, between the two ends including the branch stub, circumferentially and throughout by a corresponding design of the engraving, by an expansion chamber.

Abstract: A rotary forging and quenching apparatus and method forms and rapidly cools an axial-symmetric object from a spin formable material. The process uses a preheated billet which is clamped between opposed fixture mandrels which have a circumferential die shape and with quench solution channels running through the fixtures. The mandrels are spun and at least one contour roller of a mating circumferential die shape is brought into bearing contact against the billet in order to spin-form the material into the desired die shape. The mandrel and peripheral margin of the spinning billet are flooded with a quench solution coolant while being spin formed. This process streamlines the manufacturing of wheels or other axial-symmetric parts like cylinders, hemispheres, cones, etc. Typically, parts that require heat treatment, like aluminum alloys, will benefit from this process. The process minimizes the distortion encountered in heat treatment and eliminates the need to add extra material to ensure final dimensions.

Abstract: A negative-angle forming die includes a lower die half and an upper die half. A rotary cam is rotatably provided in the lower die half, and a slide cam is slidably opposed to the rotary cam. An automatic retractor is provided in the lower die half for pivoting the rotary cam to a position allowing the work to be taken out of the lower die half after a forming operation. The rotary cam is divided into an end rotary cam and a main rotary cam which are both disposed on a same axis of pivoting. The end rotary cam is not pivoted for an initial predetermined period of the retraction, and thereafter, the end rotary cam is moved axially toward the main rotary cam.

Abstract: A method and apparatus for forming a container component has a fixed stock plate and cut edge mounted on a base at a first level for forming a disk-shaped blank from a strip of sheet material. A blank and draw die is mounted at a second level which forms the disk-shaped blank into a shallow cup upon advancement of a punch assembly through the die. A profile pad is mounted at a third level on the base and imparts a profile on the bottom wall of the shallow cup as the punch assembly continues a downward stroke. An air stream ejects the profiled container component from the press at the third level.

Abstract: A riveting tool for fastening a hollow rivet to a curved workpiece is disclosed. The tool includes a main body provided with a forwardly-extending barrel terminating in a forked distal end. The main body has a power-operated rotor formed with a central hexagon stem in alignment with the barrel. A sleeve is movable within the barrel to an extended position and is spring-loaded in such a way that it is normally in the extended position but may be retracted into the barrel when being pressed backward. The riveting tool further includes a screw having a socket head engaged with the central hexagon stem of the rotor. The screw extends out of the barrel through the sleeve.

Abstract: The invention relates to a device for straightening bridges that have had their lower girders bent by trucks passing underneath having loads higher than the clearance afforded by the bridge. The invention contemplates using a threaded rod with two clamping members to engage both the bent beam and a rigid part of the bridge to as to gradually bend the beam back into alignment by rotating a nut portion on the rod so as to turn the rod and allow one clamping member to move slowly along the rod. The clamping members have a portion designed to engage the flange area and thereby allow firm engagement of the beam by the straightening device.

Abstract: A hand held dent pulling device for attachment to and use in combination with a MIG or similar welder. The device features a elongated body member with an axial cavity and a face plate mount at a front end. An elongated shaft slidably engages the body member through the axial cavity and is biased toward the face plate. The shaft has an electrode attachment at one end and an attachment for a welder at the opposite end. The elongated shaft is selectively laterally translatable in its mount to the body. The front tip of the electrode is selectively translateable through an aperture through the face plate allowing the user to weld the electrode to the metal body being repaired and to draw the metal toward the face plate by laterally translating the elongated shaft. A handle is provided to grip the device and to translate the shaft once the device is welded to the metal body. Removal from attachment to the body done with a twist of the device snapping off the electrode tip.

Abstract: An air bag calibrator that is used to calibrate a plurality of seat sensors within a seat simultaneously. The calibrator uses controlled pressure contained within an air bladder and an air press cylinder to apply a controlled force across an entire seat surface that actuates all of the seat sensors in a consistent and repeatable manner, a major improvement over existing seat calibration methods. This is accomplished by loading a seat onto the calibrator, recording a baseline seat sensor value for each of the seat sensors, extending the air press cylinder to an extended position and applying a controlled force across the entire seat surface. The air pressure in the air bladder is then increased or decreased to a target pressure for a predetermined time, at which time an actuated seat sensor values for each of the seat sensors is recorded.

Abstract: An emergency water system testing system (20) is provided which includes a retaining tank (21) having inlet conduits (23 and 24), a vent (25), and an outlet conduit (26). The testing system also includes a support carriage (33) having four lockable wheels (34) and a flow measuring device (36). The system may be coupled to the coupler valve (14) of an emergency water system (12) so that water expelled from the emergency water system is contained on sight while the flow rate of the water is determined. In this manner the water expelled from the water system may then be moved to a remote location and controllably discharged.

Abstract: An apparatus for measuring the strength of a pressure pulse created from a laser peening device. The apparatus is reusable, and includes a pressure-sensitive medium, a back-up disk, and a cap, all disposed within a housing having a removable lid. All components of the apparatus are replaceable, thereby allowing an operator to utilize the apparatus more than once despite the harsh environment of laser peening.

Abstract: A sensor for determining the presence of hydrogen and for measuring the amount of hydrogen present in the vicinity of the sensor. The sensor comprises a metal hydride hydrogen-absorbent material AB5 which selectively absorbs hydrogen and expands upon such absorption. This expansion depends on the amount of hydrogen absorbed and the expansion is detected and measured either by measurement of a change in capacitance of the sensor or by the change in tunnel current flowing through the sensor. A method for determining the presence of hydrogen and for measuring the amount of hydrogen present using the metal hydride hydrogen-absorbent material AB5-based sensor.

Abstract: An apparatus for the continuous measurement of the interchangeability of LPG/Air Mixtures with Natural Gas, having a sensor that measures the relative density (specific gravity) of an LPG/air mixture, and associated controls for gas sampling, signal processing and computation of mixture properties and interchangeability factors. The entire apparatus, gas sampling components, and signal conditioning devices are carried in one or more housings, having one sample gas inlet port and one or more waste gas outlet ports, one gas density sensor, one or more microprocessor-based signal processing units, and one or more connected operator interfaces. The measurement data from the gas density sensor is combined in the microprocessor-based signal processing unit with user-provided information about the properties of the LPG feedstock.

Abstract: Apparatus 10 for condition monitoring the integrity of a rivet 12 joint holding together sheets 14 and 16 of a structure 18 includes a substantially fluid impervious pad 20 for covering the heads of the rivets 12 and an adjacent surface 24 of the structure 18. The pad 20 has a first surface 26 for placement over the rivets 12 and the surface 24. An inner portion of the surface 26 is formed or otherwise configured to define a fluid flow region 28 between the pad 20 and the rivets 12/surface 24 across which fluid can flow. The region 28 is coupled to a constant vacuum source 30 via a conduit 32 and a series coupled high fluid flow impedance 34. A transducer 38 and display 44 coupled in parallel across the impedance 34 provides an indication of change in differential pressure across the high impedance which in turn provides an indication of the presence or development of a flaw in the rivets joint.

Abstract: A pipe leakage detection system which includes a flexible probe with a body portion of sufficient length to pass along a pipe. Pairs of seals define a seal volume with the inner pipe wall. An adjacent test region can be used to determine leakage. A source of fluid pressure is applied to lines. With equal pressure in both seal and test regions as indicated by a manometer no leak will occur around the seals. A deliberate outgoing flow rate is allowed from a line and any differential in flow, as detected by flow meters, will indicate an actual leakage rate.

Abstract: The present invention is directed to a method for completing the commissioning of a subsea pipeline by purging with a compressed gas to dewater and dry the line wherein the operation is done on the seabed. More specifically, the method is carried out with a subsea vechicle (hereinafter “SV”) that powers pumps located on the seabed or are carried by the SV to inject/remove chemical, dewater, and dry, the pipeline. The present invention may be part of the commissioning of a new or old pipeline or a new portion of a pipeline in which a purging of the line with a compressed gas and drying of the line is required. After commissioning, product flows through the pipeline.

Abstract: The invention comprises measuring or responsive instruments, including (but not limited to) viscometers, having a music wire (20) or like high tensile wire support between driving/driven shaft assemblies (18, 16) and appropriate mounting to eliminate drag, friction, radial misalignment, vibration problems, especially at high rotational speeds, and afford an enhanced accuracy and speed of measurement or other response of the instrument as a whole, including such specific features allowing large angular deflections or small ones (full scale under one degree) and axial and radial rigidity. The instrument can also be used with a plate for cone plate, oscillation and normal force measurements.

Abstract: A pressure self-compensating tensiometer and method to in situ determine below grade soil moisture potential of earthen soil independent of changes in the volume of water contained within the tensiometer chamber, comprising a body having first and second ends, a porous material defining the first body end, a liquid within the body, a transducer housing submerged in the liquid such that a transducer sensor within the housing is kept below the working fluid level in the tensiometer and in fluid contact with the liquid and the ambient atmosphere.

Abstract: In a method for determining the hardness of a product, for instance fruit, during a measuring cycle, comprising: supporting the product, tapping the product with a tapping device at least one position of the product, as a result of which the product as a whole is set in its natural vibration and produces vibration signals, sensing the vibration signals with a signal sensor, and processing the vibration signals with a signal processing device, in which the hardness FRi of the product is determined, and further comprising: sensing the signals produced by the tapping device with a second signal sensor, processing the vibration signals with a second signal processing device, the elastic properties of the product being determined in a volume range around the above at least one position, determining the hardness FIi of the product, comparing FIi and FRi and checking the comparison with a pre-adjusted value, the tapping and sensing with the second signal sensor being repeated when the comparison does not satisfy the

Abstract: A load machine for a combustion engine test bench includes at least one eddy-current brake associated with at least one electric drive. The brake includes a toothed ferromagnetic rotor secured to a shaft mounted so that it can rotate through a casing containing at least one induction coil borne by an internal peripheral region of the casing, so as to generate a magnetic field across which the rotor is intended to pass in order to generate eddy currents which brake the rotation of the shaft. The shaft is coupled to the combustion engine to be tested, and the electric drive is a variable-reluctance electric motor.

Abstract: An engine tracking filter system that obtains information from two or more operating conditions to estimate health parameters P, performance parameters Yp, and sensor estimates Ys, is described. Such multipoint estimation of engine health enables estimation of all engine health parameters rather than only a few engine health parameters for use in engine component diagnostics, trending, and fault detection and isolation. In addition, such estimation is believed to provide improved estimates of sensed parameters for use in sensor redundancy management and sensor elimination, and also is believed to provide improved estimates of performance parameters for use in model based control to reduce required temperature, stall, and other margins.

Abstract: The invention relates to the performance evaluation of an oxygen gas sensor in a motor vehicle, where the oxygen gas sensor is used to measure the oxygen content of the combusted air fuel mixture of a motor vehicle exhaust. The method involves measuring the fall time for the detected oxygen level to fall to a pre-determined lower threshold after the fuel supply to the engine has been cut off, and if the measured fall time exceeds a pre-set time, producing an oxygen sensor degradation signal.

Abstract: A diagnosis system for a valve system of an internal combustion engine includes an airflow meter which detects an intake air flow rate fed to the engine. A control unit coupled to the airflow meter calculates an accumulated value of an intake airflow rate during a particular period by each cylinder and diagnoses the valve system of the engine on the basis of the calculated accumulated value. Therefore, the diagnosis system executes an accurate diagnosis by each cylinder without further providing sensors.