摘要:
A sensor (10) optically coupled to the combustion chamber (10') of an internal combustion (IC) engine is kept free from contaminating or dirt deposits, or the like, by subjecting the sensor to mechanical shocks or vibration. The mechanical shocks or vibration are obtained by the engine itself by controlling the engine to operate for a predetermined time period as set by a monostable flip-flop (FF) (18) under controlled knocking conditions, the shock waves within the combustion chamber causing flaking off or dropping off of contaminating deposits. Controlled knocking can be obtained by advancing ignition timing by additional control of an ignition system (19) in a direction of excessive spark advance, or overriding a knocking inhibiting system already present on the engine. The degree of contamination of the sensor can be determined, for example, by integrating the light received over a predetermined angle of rotation of the engine crankshaft and comparing this rotation with the amount of fuel supplied to the engine for combustion, for example by comparison with timing of a fuel injection pulse, or the like.
摘要:
To avoid temperature shock and mechanical damage to oxygen sensors with ion conductive solid electrolytes exposed to the exhaust gases of internal combustion engines, a catalyst, for example in the form of aluminum oxide pellets having a catalyzing surface layer, is located to surround the oxygen sensor, or just in advance of the oxygen sensor in a bypass pipe, branching off from the exhaust gas pipe of the engine to take samples of the exhaust gases so that the sensor and catalyst form an assembly, or sensing combination. The catalyzing layer may be platinum, or a platinum metal, or an alloy of platinum with aluminum, cobalt, nickel, or chromium, or may be mineral wool, or wool of glass, or asbestos fibers having their surface coated with any of the foregoing catalysts.
摘要:
To improve operation and output voltage, particularly at 400.degree. C. and less, an oxygen sensor, especially adapted to determine oxygen content of automotive exhaust gases, is constructed by utilizing two electrodes applied on a body of stabilized zirconium dioxide, for example a closed tube, by making an electrode exposed to the exhaust gases in form of a mixture of finely dispersed ceramic material and a platinum-rhodium alloy, the ceramic material being present at about 40% (by volume) and 60% (by volume) platinum-rhodium alloy of 50-94% platinum and 50-6% rhodium (by weight). The second electrode, exposed to a reference gas comprises an alloy of palladium and another noble metal in a ratio of about 19-90% (by weight) Pd and 81-10% (by weight) noble metal. This electrode may also contain up to 40% (by volume) finely dispersed ceramic material. The electrode exposed to the exhaust gases is covered with a porous coating. The electrodes can be applied as aqueous or organic solutions of soluble noble metal compounds or suspensions, colloidal suspensions, with organic solvents, and the like, and subsequent sintering.
摘要:
To heat the glow plug for an internal combustion engine, a spiral band or ribbon is wound in an essentially co-planar spiral about a central bolt secured to the bottom of the glow plug, the outer terminal of the spiral being connected to a lead-in with highly positive temperature coefficient of resistance to provide for self-limiting current flow upon heating of the glow plug. All free spaces in the glow plug are filled with a highly heat-conductive insulating material, for example magnesium oxide.
摘要:
A housing of the device has a passage formed with two spaced open ends and with an inner circumferential shoulder. A tubular member of ion-conducting solid electrolyte material has a first closed-ended portion projecting from one of the open ends, and a second portion extending through the passage and being formed with an outer circumferential flange an axial end face of which faces the one open end and is supported by the shoulder. The interior of the tubular member is in communication with the ambient atmosphere, and an electron-conductive inner electrode is provided on an inner surface of the tubular member and conductively connected with an outside terminal portion. An electron-conductive outer electrode is provided on an outer surface of the tubular member and conductively connected with the housing. A compensating arrangement is provided on the housing fixed with reference thereto and engages the second portion of the tubular member in such a way as to compensate for differential coefficience of thermal expansion and contraction of the material of the housing and of the tubular member, respectively. This prevents relative movements of the housing and tubular member when such differential expansion or contraction occurs.
摘要:
To positively exclude oxygen from a heating spiral located within the interior of a glow plug, so that the heating spiral can use a material having a high positive temperature coefficient of resistance, an insulating bushing separates a central connecting bolt from the surrounding metal sleeve and at least one, and preferably both the bolt and the metal sleeve are formed with circumferential matching ridges and grooves into which the insulating bushing will be pressed to provide an effective seal and a long, tortuous path for any possible leakage of air past the seal, even under the extremes of operating conditions and temperature gradients to which glow plugs are exposed in use. To further exclude oxygen from the heating spiral, the filler material adjacent the sealing bushing can include material having a high affinity to oxygen, such as aluminum or magnesium, so that any oxygen molecules which might leak past the seal will be bound thereby.
摘要:
To prevent damage to the heating wire of an electrically heated glow plug due to non-uniform expansion of materials within the glow plug upon heating thereof, and particularly due to excessive expansion of filler material surrounding a spiraled heating wire, the filler material is made in two sections, one being located within the spiral of the heater wire and comprising a material of a thermal conductivity of expansion approximately matching that of the heater wire, typically high-temperature annealed aluminum oxide, magnesium aluminum spinel, silicon nitride, boron nitride, silicon carbide, or the like, the outer section between the heater wire and the inner wall of the glow tube being of a material of good heat conductivity, such as magnesium oxide. In manufacture, the first material is introduced into the heater wire spiral in the form of a compacted rod which, after assembly to the tube and introduction of the second material, is crushed by diametrical reduction of the tube after closing thereof, for example by hammering, rolling or swaging.
摘要:
To permit use of a standard starting switch customary in Otto engines to start automotive-type Diesel engines requiring energization of a glow plug, the "start" position of the control switch is unstable, for example spring-loaded, and returns the switch to "on" position upon release. The ON position also simultaneously forms the pre-heat switch position. The system includes a first relay having its connecting contacts connected to the glow plug and to a source of power, and a second relay forming a transfer switch with one terminal set connected as a self-holding circuit. The coil of the first relay is connected through the other set of transfer contacts of the second relay to the ON terminal of the switch to form the pre-heat circuit when the second relay is de-energized. The "start" position connects the starting motor. The coil of the second relay is energized from a common transfer junction either when the switch is in the "start" position or when a heater switch, included in the circuit of the glow plugs, has sufficient current flowing therethrough which also causes the glow plugs to become hot.
摘要:
A housing of the device has a passage formed with two spaced open ends and with an inner circumferential shoulder. A tubular member of ion-conducting solid electrolyte material has a first closed-ended portion projecting from one of the open ends, and a second portion extending through the passage and being formed with an outer circumferential flange an axial end face of which faces the one open end and is supported by the shoulder. The interior of the tubular member is in communication with the ambient atmosphere, and an electron-conductive inner electrode is provided on an inner surface of the tubular member and conductively connected with an outside terminal portion. An electron-conductive outer electrode is provided on an outer surface of the tubular member and conductively connected with the housing. A compensating arrangement is provided on the housing fixed with reference thereto and engages the second portion of the tubular member in such a way as to compensate for differential coefficience of thermal expansion and contraction of the material of the housing and of the tubular member, respectively. This prevents relative movements of the housing and tubular member when such differential expansion or contraction occurs.
摘要:
An optical transmitter for converting a thermocouple voltage into an optical pulse train and a low pass input filter are contained in respective spaces in a soft magnetic housing. The input filter is in lead wires from a thermocouple whose hot junction is embedded in the tip of the insulator of a spark plug of an internal combustion engine. The housing itself forms part of or is connected to the H.T. lead to the centre electrode of the spark plug. The housing is surrounded by insulating material which is itself surrounded by an earthed screening casing. The low pass filter is symmetrically constructed, both electrically and mechanically.The filter prevents interference from reaching the circuitry of the optical transmitter and the housing and the casing prevents the generation and transmission of radio interference.