Abstract: Various embodiments disclose a glow plug for a solid oxide fuel cell system. The glow plug includes a housing having a first end portion and a second end portion. The glow plug includes a heating element longitudinally disposed in the housing, extending from the second end portion of the housing towards the first end portion and extending outwardly from the housing for igniting fuel. Further, the glow plug includes a pair of coiled wires electrically connected to the heating element. Further, the glow plug includes a potting compound disposed within the second end portion of the housing for securing electrical coupling of the pair of coiled wires with the heating element. Furthermore, the glow plug includes a sealing element configured to form an air-tight connection between the housing and the heating element. The sealing element is positioned on top of the potting compound.

Abstract: Hydrogen generation assemblies, hydrogen purification devices, and their components, and methods of manufacturing those assemblies, devices, and components are disclosed. In some embodiments, the devices may include an insulation base having insulating material and at least one passage that extends through the insulating material. In some embodiments, the at least one passage may be in fluid communication with a combustion region.

Abstract: This document describes a heating rod for a glow plug with a ceramic glow element having a glow tip at its front end and a connector portion at its rear end, a contact element making electrical contact with the connector portion of the glow element, and a sheath, from which the front end of the glow element protrudes. According to this disclosure, the contact element is pressed against the glow element under pre-tension. Furthermore, this document describes a method for producing such a heating rod and a glow plug with such a heating rod.

Abstract: A method of making a hot surface igniter is described. A silicon carbide composition that includes both fines fraction and a coarse fraction is sintered in a nitrogen and argon reducing atmosphere in a manner that controls the incorporation of nitrogen with in the lattice of recrystallized silicon carbide. The controlled incorporation of nitrogen in the lattice provides enhanced control over heating and electrical properties, while simultaneously achieving a lower surface area fully recrystallized structure for oxidation resistance and long service life.

Abstract: A method is provided for controlling one or more glowplugs in a compression-ignition engine. The controlling of the glowplug involves the prediction of a glow plug temperature to control a power supply to the glowplug. A supplied power to a glowplug and a combustion chamber temperature is determined. A temperature of the glowplug is predicted and the predicted glowplug temperature is used to control a power supply to the glowplug. The predicted glowplug temperature is derived from a numerical solution of a differential equation for the glowplug temperature. The differential equation is nonlinear in the glowplug temperature.

Abstract: A method for determining a heating characteristic of a glow plug, wherein pulse-width-modulated voltage pulses are applied to the glow plug and an electric variable is measured repeatedly during a voltage pulse with the heating characteristic of the glow plug determined by evaluating the difference of successive measurement results of this variable.

Abstract: The present invention proposes a hot surface igniter (HSI) controller which is transformerless and which is capable of delivering power from a 120/240 VAC RMS mains voltage, for example, to a load whose nominal operational voltage is equivalent to 24 VAC RMS, for example, sinusoidal full wave AC Voltage. The controller provides an impulse range which is mainly designed to deliver power to hot surface igniter active loads with sufficient thermionic inertia and mass, and where the real voltage shape of supplied power is unimportant. This is achieved by supplying half-cycle pulses to the HIS that are separated by even number of half-cycles that are not supplied to the HIS. Thus the consecutively applied half-cycles are always of opposing polarity.

Abstract: The invention relates to a glow plug comprising a housing in which an inner conductor is disposed, a metal sleeve which is inserted into the housing, and a ceramic glow pin which is disposed in the metal sleeve, wherein the two ends of the glow pin protrude from the metal sleeve and the rear end of the pin is connected to the inner conductor, and wherein the metal sleeve has a tapering section at the rear end, the section enclosing a tapering section of the glow pin. According to the invention, the glow pin is pressed into the metal sleeve. The invention further relates to a method for connecting a pin made of functional ceramic to a metal sleeve.

Abstract: A first via and a second via pass through a layer of a multi-layered circuit board. A first set of electrical transmission line segments, each having a first thickness, is aligned at a first area on the layer between the first and second vias. A second set of electrical transmission line segments, each having a second thickness that is greater than the first thickness, are aligned at a second area that is offset to the first area and to the first and second vias. The first set of electrical transmission line segments is connected to the second set of electrical transmission line segments to form an electrical transmission line, which has an average impedance that matches a line impedance of a uniform thickness line.

Abstract: The invention relates to a method for operating a heating element in a motor vehicle by pulse width modulation, wherein fluctuations in the supply voltage are compensated for by adapting the duty cycle so as to achieve a desired heating output. According to the invention, during a voltage pulse the voltage that is present at the heating element and/or the current flowing through the heating element are measured at specified intervals, and the measured values or values determined therefrom are added to calculate a sum value, which rises with the energy that is fed into the heating element by the voltage pulse, and the voltage pulse is ended at the latest when the sum value has reached a target value. The invention furthermore relates to a glow plug controller for carrying out the method according to the invention.

Abstract: An electrification control apparatus (101) for glow plugs GP1 to GPn includes temperature-raising-period electrification control units S3 to S7, S31, S32 for raising the temperature of a heater section (2) of each glow plug. The control units perform electrification control in such manner that, even when a first glow plug GP1 and a second glow plug GP1e, which are of the same industrial part number but differ in resistance due to a characteristic variation therebetween, are selectively connected to the electrification control apparatus (101) and electrification control is performed therefor, at sampled timings t during the temperature rise, electric power of the same magnitude P(t) as that of electric power supplied to the first glow plug GP1 is supplied to the second glow plug GP1e.

Abstract: A ceramic heater comprising a ceramic body, a heat generating resistor buried in the ceramic body, an electrode pad that is electrically connected to the heat generating resistor and is formed on the surface of the ceramic body and a lead member bonded onto the electrode pad.

Abstract: There is provided a control device for a glow plug, capable of controlling the energization of a resistance heater of the glow plug by a resistance control process while attaining good resistance control response under cooling of the heater by fuel injection and combustion gas and thereby stably controlling the amount of heat generated by the heater. The resistance heater includes a resistive heating element having a ratio of electrical resistance R1000 at 1000° C. to electrical resistance R20 at 20° C. of 6 or larger, and the glow plug is mounted with at least part of the resistive heating element being protrudingly located in an engine combustion chamber. Under such a condition, the control device controls energization of the resistance heater in a steady control mode to adjust electrical power supplied to the resistance heater in such a manner as to keep a resistance of the heater within a predetermined range.

Abstract: A sheathed element glow plug having an ionic current sensor and a method of operating such a sheathed element glow plug are provided. The sheathed element glow plug includes a housing and a rod-shaped heating element arranged in a concentric bore in the housing. The heating element has at least one insulation layer, a first feeder layer, and a second feeder layer, the first feeder layer and the second feeder layer being connected by a web on the combustion chamber-side end of the heating element, the first and second feeder layers and the web being made of an electrically conducting ceramic material, and the insulation layer being made of an electrically insulating ceramic material. The heating element has at least one ionic current detection electrode made of an electrically conducting ceramic material.

Abstract: A sheathed-element glow plug having an ionic-current sensor, as well as a method for operating a sheathed-element glow plug having an ionic-current sensor are described, the sheathed-element glow plug having a housing and a rod-shaped heating element arranged in a concentric bore hole of the housing. The heating element has at least one insulating layer as well as a first lead layer and a second lead layer, the first lead layer and the second lead layer being connected via a bar at the end of the heating element on the combustion chamber side, the first and second lead layers and the bar being made of electroconductive ceramic material, and the insulating layer being made of electrically insulating ceramic material. The heating element has a first electrode for detecting ionic current and a second electrode for detecting ionic current which are embedded in the insulating layer or applied on the insulating layer.

Abstract: A ceramic heater element and a glow plug incorporating the novel heater element. The heater element has a base portion and a heater portion. Conductive, insulative and resistive layers extend through both the base and heater portions. An outer conductive layer is applied to the outside of the base portion to provide a highly conductive return path. This lends to limit the heating of the resistive layer in the base portion and results in better and more reliable heat concentration in the heater portion. The heater element is further provided with a waterproof non-electrically conductive outer layer. The heater element can be assembled to form a glow plug for a diesel engine.

Abstract: A heater comprising: a cylindrical metal shell having an engagement portion, the portion having a narrowed diameter; a cylindrical heating tube comprising a closed top end, a fitting portion, a smaller diameter portion, a base end side-larger diameter portion and a top end side-larger diameter portion, wherein a base end of the heating tube protrudes into an inside of the metal shell, the fitting portion is fitted into the engagement portion in interference fit, the smaller diameter portion comprises the base end of the heating tube, the smaller diameter portion has a smaller outer diameter than an inner diameter of the engagement portion, the base end side-larger diameter portion is formed between the fitting portion and the smaller diameter portion, the base end side-larger diameter portion has an outer diameter larger than or equal to the inner diameter of the engagement portion, the top end side-larger diameter portion is formed adjacent to a top end side of the fitting portion, and the top end side-large

Abstract: A ceramic sheathed-type glow plug, whose ceramic heating element is made of an electrically conductive conducting layer and an electrically insulating layer, is described. The conducting layer is made of lead layers and a heating layer. The higher specific electrical resistance of the heating layer allows the temperature of the heating layer and the combustion chamber to be determined. The electrical contact between a connector element and the heating element is established by a contacting element, which is in the form of a pellet made of an electrically conductive powder.

Abstract: The present invention is to provide a glow plug (1) with an ion current detecting function, which is mounted in a combustion chamber of a Diesel engine. The glow plug includes an insulator (8); a heating element (6) embedded in the insulator and energized through a pair of lead wires (11a, 11b) to generate heat; and an ion current detecting electrode (14) embedded in the insulator with a portion exposed into a flame in the combustion chamber so that an ionization state in the flame can be detected. The heating element of the glow plug promotes ignition and combustion of fuel in the combustion chamber (7) due to its heating action caused when running the heating element hot. The ion current detecting electrode detects an ionization state in the combustion flame. When detecting ion current, the ion current detecting electrode and the adjacent inner wall of the combustion chamber form two electrodes for capturing positive and negative ions existing between both when burning the fuel.

Abstract: A ceramic heater element and a glow plug incorporating the novel heater element. The heater element has a base portion and a heater portion. Conductive, insulative and resistive layers extend through both the base and heater portions. An outer conductive layer is applied to the outside of the base portion to provide a highly conductive return path. This tends to limit the heating of the resistive layer in the base portion and results in better and more reliable heat concentration in the heater portion. The heater element can be assembled to form a glow plug for a diesel engine.

Abstract: Apparatus for controlling the temperature of a cooking location of a cooking unit includes a temperature sensor having an outer tube and an inner rod received within the tube and having a different coefficient of expansion, a switch base operatively connected to the temperature sensor and carrying electric contacts actuated by the temperature sensor, and an igniter connected to the temperature sensor and/or switch base.

Abstract: Glow plug with a heating rod formed of an inner pole (2) and a glow tube (5) in which there is heating element (3) which is electrically connected to the inner pole (2). At least in the area of its tip, the glow tube (5) is provided with a coating (7) of ceramic material, especially yttrium-stabilized zirconium dioxide which has a subsurface or adhesive layer (6) of NiCrAlY which is directly provided on the glow tube (5).

Abstract: Glow plug with a heating rod formed of an inner pole (2) and a glow tube (5), in which a heating element (3) is located which is electrically connected to the inner pole (2). The glow tube (5) is provided with protective coating (6) at least in the area of its tip. The protective coating is selected from the group consisting of materials which include NiCrAlY, CoCrAlY, CoNiCrAlY, NiCrAl, NiCr, NiCrFe and NiCrWCo.

Abstract: Glow plug with a metallic hollow body 1 in which a ceramic heating rod 2 is arranged such that it projects axially on one side of hollow body 1. The heating rod 2 is formed of a ceramic conductor 6 which is embedded in a ceramic insulator 7 and is connected to the power supply terminals, i.e., to ground via the metal of hollow body 1 and via a plug terminal 3. The contacts of the ceramic conductor 6 with the power supply terminals are formed by contact surfaces 8, 9 on the ceramic conductor 6, via which the conductor is in contact, on the one hand, with metallic hollow body 1, and with plug terminal 3, on the other hand. The contacts are preferably pressure loaded by generating a prestress between the components in contact. Preferably, metallic contact parts, for example, contact rings 10, 11, are provided at the contact points between the contact surfaces 8, 9 and the metallic hollow body 1 and plug terminal 3.

Abstract: A glow plug having an interior pole and a glow tube with a tip portion, a heating element located in the tip portion, and a regulating element, formed of an electrically conductive material having positive temperature-resistance coefficients, arranged in the glow tube. The interior pole of the glow plug is serially connected with the regulating element, the regulating element is serially connected to the heating element, and the heating element is serially connected with the glow tube tip in a construction for minimizing heat transfer between the regulating element and the interior pole.

Abstract: Rod flame glow plug for preheating the intake air of an autoignition internal combustion engine with a housing having a fuel connection with a metering device and an electric connection, and at least one heating rod located in the housing. The heating rod is formed of a glow tube (8) filled with an electrically insulative filling material (10) and at least one regulating coil (2) and a heating coil (1). The coils are embedded in the filling material (10) and are connected in series to one another and with the electric connection (9). The regulating coil (2) is formed of a CoFe alloy.

Abstract: A glow plug for an air compressing internal combustion engine of the type having a tube which is closed at one end and connected to a plug housing on an opposite end with a wire filemant-like resistance element disposed in an insulating material within the tube and formed two series-connected resistance filaments, of which the rear resistance filament, serves as a regulating filament, having a higher positive temperature resistance coefficient than the front resistance filament, which serves as a heating filament, is improved so as to enable the heating up time to be reduced without adversely impacting upon the effective life of the glow plug. In accordance with various embodiments, this result is achieved through the use of, for example, special alloys for the material of the regulating filament which have a resitance at 1000.degree. C. that is greater than their resistance at 20.degree. C. by a resistance ratio over about 7.5:1, and preferably greater than 12:1, and in particular, about 14:1.

Abstract: An electrically conductive ceramic material containing at least 20 wt % of Mo.sub.5 Si.sub.3 C and having a resistance-temperature coefficient no greater than 5.times.10.sup.-4 deg.sup.-1 is used to make the heating element of a self-controlling type glow plug having a resistor with a larger temperature-resistance coefficient, such as iron or nickel, connected in series to the heating element for controlling the supply of electric current to the heating element. The ceramic material is made by firing a ceramic powder mixture of Mo and Si mixed with carbon black.

Abstract: An improved mechanical joint structure is provided and adapted for positively retaining a heating element within a bore of a body of a glow plug. The glow plug includes a body, a heating element and a ferrule. The ferrule is sealingly positioned radially between an internal surface of the body bore and a peripheral surface of the heating element. The glow plug further includes a compressing structure for positively compressing an internal surface of the ferrule against the peripheral surface of the heating element in response to the heating element being forced into the body bore by, for example, the gas pressure developed in an operating engine combustion chamber.Unlike conventional brazed or interference joints used in typical glow plugs, the present invention provides a normal force (F.sub.n), for sealing the heating element, and an axially-directed frictional force (F.sub.f), for retaining the heating element, which both increase as the heating element is forced deeper into the body bore.

Abstract: The service life of conventional glow plugs is extremely short when they are continuously energized at an elevated temperature during engine operation in order to assist ignition of non-autoignitable fuels. Such glow plugs typically fail due to thermal stresses and/or oxidation and corrosion.Herein is disclosed an improved heating element assembly adapted for incorporation in a glow plug. The heating element assembly includes a monolithic sheath having a relatively-thin and generally annular wall defining a blind bore. The heating element assembly further includes a heating device positioned in the blind bore and adapted to emit heat, and a heat transfer device adapted to transfer heat from the heating means to the sheath. The heating device includes a heating filament and a ceramic insulator. THe heating filament is protected against oxidation by being encapsulated in the insulator. The insulator is protected against corrosion by being encapsulated in the sheath.

Abstract: The service life of conventional glow plugs is extremely short when they are continuously energized at an elevated temperature during engine operation in order to assist ignition of non-autoignitable fuels. Such glow plugs typically fail due to thermal stresses and/or oxidation and corrosion. Herein is disclosed an improved heating element assembly adapted for incorporation in a glow plug. The heating element assembly includes a monolithic sheath having a relatively-thin and generally annular wall defining a blind bore. The heating element assembly further includes a heating device positioned in the blind bore and adapted to emit heat, and a heat transfer device adapted to transfer heat from the heating means to the sheath. The heating device is protected by the sheath formed of a preselected material which is chosen and configured so as to minimize failure of the heating element assembly caused by thermal stresses, oxidation and/or corrosion.

Abstract: A ceramic heater type glow plug includes a U-shaped ceramic heater consisting of a resistive ceramic material, a hollow metal holder, an external connecting terminal, a power control resistor, and a connecting unit. The hollow metal holder has a distal end portion for supporting the ceramic heater via insulating members. The external connecting terminal is insulatingly supported at a rear end of the metal holder. The power control resistor is arranged between one of terminal caps at a rear end side of the ceramic heater housed in the metal holder and the external connecting terminal and performs power supply control with respect to the ceramic heater. The connecting unit connects another one of the terminal caps at the rear end side of the ceramic heater to the metal holder. The power control resistor consists of a metal material having a larger positive resistance temperature coefficient than that of the resistive ceramic material constituting the ceramic heater.

Abstract: A glow plug including a shell provided with an axially extending bore and a tubular sheath partially located in the bore and partially projecting from the shell. At least a first electrical resistance is located in the portion of the sheath extending outside the shell. The tubular sheath is filled with two different powders. Both powders have good electrical insulating characteristics. The first powder is located in the free closed end of the sheath and has good thermal conductivity characteristics. The second powder is located in the portion of the sheath located in the shell bore and has good thermal insulating characteristics. The interface between the two powders can be varied with the design of the glow plug and the type of resistance located in the sheath.

Abstract: A battery operated barbeque igniter has an igniter implement with an axially extending heater element and a sheath to keep the heater element from accidentally burning anything or anyone as it cools after use. The heater element is positioned inside a metal tube which is closed at one end. The heater element includes a spiral tungsten filament supported between two coaxial quartz tubes. The outer quartz tube is closed at one end. A central steel rod extends the length of the metal tube and serves both to position the tungsten filament inside the metal tube and as an electric conductor to one end of the filament. The rod is brazed to the inner quartz tube and the filament at one end of the filament. The outer quartz tube is brazed to the inner quartz tube and the other end of the filament. The sheath receives the heater element and is slotted to permit cooling of the heater element without inadvertent contact with it.

Abstract: A glow plug for a diesel engine includes a U-shaped ceramic heater of SIALON supported by a hollow metallic holder. The heater has a U-shaped heating portion projecting from one end of the holder and is supported therein by a pair of parallel ceramic lead portions of a thicknesses greater than the heating portion. One lead portion is electrically connected to the interior of the holder and the other lead portion is electrically insulated from the holder and electrically connected to an external connecting terminal extending into the other end of the holder. The lead portions are spaced from each other to define a slit therebetween open to the interior of the holder. A sintered ceramic sheet of SIALON integrally seals the slit against entry of combustion gases into the interior of the holder.

Abstract: A diesel engine glow plug includes a hollow holder, a ceramic heater, an electrically conductive annular member, an external connecting terminal, and an insulating sleeve. The annular member is interposed between the rear end portion of the ceramic heater and the distal end portion of the hollow holder. The external connecting terminal engages with the rear end portion of the ceramic heater from the rear end portion of the holder through an interior of the holder. The insulating sleeve is housed in the hollow holder to electrically insulate the external connecting terminal from the hollow holder. The ceramic heater includes a U-shaped heating portion and a pair of parallel lead portions extending backward from the heating portion and terminating in an enlarged diameter portion defining the rear end portion of the heater. One of the lead portions is electrically connected to the holder through the annular member.

Abstract: In a glow element with a glow tube (30) closed at the outer end, in which there at least two series-connected resistors (10, 11), whereby one of the at least two resistors being conductively connected by one end to the closed end of the glow tube and the opposite end of the series-connected resistors being connected to an internal pole (9) projecting into the glow tube from the other end thereof, in order to permit an external wiring of part of the resistors in the glow element, the internal pole (9) has a tubular construction and at least one electrical conductor (8) is passed through the internal pole and is connected to a junction (12) of the at least two resistors (10, 11).

Abstract: A self-regulating temperature controlled glow plug has a hollow metal holder, a rod-like ceramic heater and a power control heater. The ceramic heater extends from one end of the holder and has embedded therein a first resistor of tungsten alloyed with rhenium or molybdenum. The power control heater includes a second resistor embedded in a dense mass of powdered insulation material filling a tubular metallic sheath. The sheath is positioned in the holder with its central portion held in spaced relationship thereto by a thermally insulating spacer at least one end thereof. The second resistor is made of tungsten, iron or nickel, has a positive temperature coefficient of resistance at least equal to and a heating capacity greater than the first resistor, and is connected in series with the first resistor.

Abstract: A self-temperature control type glow plug includes a rod heater held at a front end of a hollow metal holder and having one end extending outside the hollow metal holder. The rod heater includes a heating section made of a conductive ceramic material with a small positive temperature coefficient and a control section made of a conductive ceramic material with a positive temperature coefficient larger than that of the heating section. The heating section is formed integrally with the control section.

Abstract: A ceramic glow plug includes an unjacketed ceramic heater formed by a coiled heating wire of a high melting point tungsten alloy having a specific resistance of at least 10 .mu. ohms/cm.sup.3 embedded within a sintered ceramic body. The ceramic body has a diameter D of not more than 4.0 mm and is fitted into a hollow metallic cylinder with a tip portion thereof projecting less than three times its diameter D beyond a first axial end of the cylinder. The other end of the metallic cylinder is fitted into a mounting sleeve. The coiled portion of the heating wire is disposed substantially entirely within the projecting tip portion of the ceramic body. A resistor of iron or nickel wire may be positioned in the sleeve and connected in series with the heating wire for inhibiting overheating of the ceramic heater.

Abstract: A ceramic heater has a heater element made of a mixture including MoSi.sub.2 and Si.sub.3 N.sub.4 powder as a main ingredient and silica (SiO.sub.2) powder as an additive, a heater support member made of an electrically insulating ceramic sintered body for supporting the heater element and an electric current supply means for supplying an electric current to the heater element. The composition of the mixture for the heater element is defined so as to satisfy the following formula: 0.035.ltoreq.B/A<0.35 where A is the amount of Si.sub.3 N.sub.4 expressed by mol percent of the total amount of the main ingredient of MoSi.sub.2 and Si.sub.3 N.sub.4 and B is the amount of SiO.sub.2 expressed by mol percent of the total amount of the main ingredient of MoSi.sub.2 and Si.sub.3 N.sub.4.

Abstract: A rapid heating self-control type glow plug used for starting a Diesel engine, particularly, such a glow plug which is also used for regulating the cylinder or auxiliary combustion chamber temperature following starting and during normal operations of the engine. A resistor wire is connected in series with a heating wire embedded in a ceramic body. The heating wire is formed of a tungsten alloy having a temperature resistance coefficient at 1000.degree. C. no greater than 4 times that at room temperature, while the resistor has a positive temperature resistance coefficient at 1000.degree. C. no less than 5 times that at room temperature. Preferably, the tungsten alloy consists of tungsten and at least one of rhenium, cobalt, thorium, molybdenum and zirconium, with rhenium in an amount of 2 to 50 wt % being preferred, and rhenium in an amount of 10 to 30 wt % being the most preferable. The resistor is preferably a wire made of at least one of nickel, tungsten, molybdenum and iron.

Abstract: A sintered ceramic electric heater suitably applicable to a glow plug of a diesel engine has a heater element formed of an electrically conductive sintered ceramic integrally sintered with a support member made of an electrically insulating sintered ceramic material. The heater element is formed as a sintered body of a mixture of MoSi.sub.2 powder having an average diameter not greater than 2 .mu.m and 35 to 75 mol % of Si.sub.3 N.sub.4 powder. The average particle diameter of the Si.sub.3 N.sub.4 powder is at least twice as large as that of the MoSi.sub.2 powder so that electrically interconnecting MoSi.sub.2 particles surround scattered Si.sub.3 N.sub.4 particles whereby the resistance of the heater element becomes equal to that of MoSi.sub.2 and the temperature coefficient of the heater element is increased.

Abstract: A glow plug for a compression ignited or Diesel engine having a base member, an axial electrode and a heater member. The heater member comprising a conductive surface film heater element disposed on the surface of a dielectric substrate. The surface film heater element having one end in electrical contact with the base member and the other end in electrical contact with the axial electrode.

Abstract: A glow plug for a compression ignited or Diesel engine having a base member, an axial electrode and a heater member. The heater member comprising a conductive surface film heater element disposed on the surface of a dielectric substrate. The surface film heater element having one end of electrical contact with the base member and the other end in electrical contact with the axial electrode.

Abstract: A glow plug for preheating the combustion chamber of a diesel engine includes a tubular metal sheath (5) closed at an end to define a tip and in which an electric heating element spiral (7) is embedded within a powder (6) of an electrically insulating material. The spiral (7) is connected by one end to the sheath tip and and at its other end to a current feeder (4). The filament (8) of the spiral (7) is advantageously made of a Fe-Cr-Al alloy and is coated for an initial length (L.sub.1) of the spiral (7), from the connection location thereof with the current feeder (4), with a high electrical conductivity material (9), preferably nickel (Ni) having a very high positive temperature coefficient of resistance with respect to that of the filament (8). The uncoated end length (L.sub.2) of the spiral (7) acts as a heating element while the initial coated length (L.sub.1) acts as a control resistance element for the supply current upon increase in the sheath temperature.

Abstract: A glow plug having a hollow cylindrical metal shell, an axial electrical terminal, and a heater member protruding externally from the shell. The heater member has a surface film heater element disposed on at least one surface of an electrically nonconductive cylindrical substrate. Electrical connections between the heater element, the shell and the axial electrode are made by conductive surface films. A first conductive surface film disposed on the external surface of the cylindrical substrate makes electrical contact with the shell. A second conductive surface film disposed on the internal surface of the cylindrical substrate makes electrical contact with the axial electrical terminal. The heating element is preferably a transition metal surface film which catalytically reacts with the air/fuel mixture to enhance combustion at lower temperatures. The thermal response time of the surface film heater element from ambient to an operating temperature exceeding 800.degree. C. is less than 5 seconds.

Abstract: In a compressed air charged combustion engine, in order to improve the atomization and ignition of the injected fuel from an injection nozzle, a glow plug which extends out of its glow plug housing with a cylindrically formed heating rod is provided with an irregular outer surface in the region which is impinged by the stream of fuel. The heating rod exhibits a cylindrical form and is provided with ring grooves to form the irregular surface area. Moreover the fuel stream meets at a sharp angle onto the heating rod.

Abstract: A glow plug for preheating the combustion chamber of a diesel engine. The glow plug has a ceramic heater rod with an embedded resistor. A metal holder holds the front of the heater rod. A terminal assembly at the rear of the holder provides for two electrically isolated terminals which are connected to the heater rod by flexible, insulated wires. The insulating bush which isolates the terminals is formed by inserting insulating material between a metal pipe and the terminals. This pipe is then subject to external force to create an air-tight seal.

Abstract: A ceramic heater comprises a heat generator made of a conductive ceramic sintered body, a supporter made of an insulating ceramic sintered body for supporting the heat generator, and a metallic wire for supplying an electric current from an electrode to the heat generator. The heat generator is integrally covered with an unporous covering layer made of an insulating ceramic sintered body. The covering layer prevents the heat generator from being directly exposed to oil and water. The covering layer is made of, for example Si.sub.3 N.sub.4 or glass containing SiO.sub.2 as a main constituent into a thickness of not more than 1mm.