Abstract: An electric heating unit for heating fluid, such as air in a hair drier, includes two ring-shaped electrodes and a plurality of spaced, plate-like ceramic heating elements having a positive temperature coefficient of resistance (PTC) aligned between the electrodes. The electrodes comprise an inner ring and an outer ring disposed in a nested, concentric, spaced relationship. The PTC ceramic plates are radially arranged in aligned spaced relationship with the opposite ends of each PTC ceramic plate mechanically and electrically connected respectively to the inner and outer rings. The inner and outer rings can be formed as arc-shaped segments separated by gaps prevent damage to the PTC ceramic plates by heat strain, and are provided with slits, grooves, etc., for firmly positioning the PTC ceramic plates.

Abstract: A heating device for mounting on an air inlet manifold of a compression ignition engine to heat the air flowing to the engine comprises a thin walled tubular element closed at one end and having a fuel inlet at the other end. A ceramic plug is located in the element to direct fuel flow against the interior surface of the element. A heating element is wound about the tubular element to heat and vaporize the fuel which flows out through an opening adjacent the one end. The fuel vapor forms an air/fuel mixture which is ignited by an ignition element.

Abstract: A heater for starting an engine is disclosed which comprises a cast body and a sheathed heating element embedded in the body at the time of casting thereof and is secured to the outside surface of the lubricating oil accumulation part of the engine or a transmission case. The cast body is mounted so as to close a hole provided in the outside surface of the lubricating oil accumulation part.

Abstract: A heating device adapted to be disposed in an opening in the side wall of a compressor that is used with an air conditioner or refrigerator so that fluids in the casing of the compressor can be vaporized. The heating device includes a PTC thermistor disposed in a housing and a generally cylindrical receptacle disposed about the housing. The housing includes at least one outwardly extending, resilient, heat dissipating, arcuate fin overlying the outer surface of the housing in spaced relaton thereto. The fin is biased outwardly to engage the inner walls of a receptacle. The receptacle is welded into the opening in the sidewall of the casing of the compressor. The fins form a snug fit with the housing and provide a good heat transfer contact with the receptacle. Lead-in wires extend from the PTC thermistor to the outside of the housing so that the PTC thermistor can be connected to a power supply.

Abstract: An in-line diesel fuel heater including a hollow elongated housing in heat conduction relationship with an electric resistance heater heats diesel fuel flowing through the housing to a temperature above the cloud point of the fuel. The hollow housing contains fins or fibers to create fluid turbulence to increase heat exchange between the fluid and the housing. An analog control circuit uses a positive temperature coefficient (PTC) thermistor to regulate the temperature of the housing at a constant temperature instead of controlling the power based on a measurement of the diesel fuel's temperature.

Abstract: The disclosure describes a fuel system including a fuel line, a fuel filter, and a fuel heater which is connected to the fuel line preferably upstream from the fuel filter. The fuel heater comprises a hollow casing having an inlet for admitting fuel into the casing and an outlet for discharging fuel from the casing. The fuel heater further comprises a heating unit operatively associated with the casing and including an electric heating element disposed within the casing, an electrical connector coupled to the heating element and extending through the casing, and a mechanism mounted to the casing for sensing fuel temperature within the casing.

Abstract: Method and device for supplying electric current to ceramic heaters comprising heating resistors embedded in ceramic sintered bodies, being characterized in that direct current is supplied from a direct current supply circuit as the first current supply step and the direction of the direct current supplied to the heating resistors at the first current supply step is reversed by a switching circuit or alternate current is supplied as the second current supply step in order to eliminate or considerably reduce cracking of the ceramic sintered bodies of the ceramic heaters when the heaters are repeatedly used for a long time at high temperatures.

Abstract: An air-fuel mixture heating device for heating an air-fuel mixture supplied from a carburetor to an intake manifold includes an insulator mounted between the carburetor and the intake manifold and having a first air-fuel mixture passage communicating with the primary air-fuel mixture passage in the carburetor, an electric heater disposed in the first air-fuel mixture passage of the insulator for heating the air-fuel mixture, and a plurality of conductors embedded in the insulator and having portions connected to the electric heater and an electric power supply. The insulator has access holes extending to the portions of the conductors for allowing said portions to be joined to the electric heater therethrough. The access holes are filled up with masses of sealing resin after said portions are joined to the electric heater.

Abstract: The disclosure describes a heating apparatus for a fuel system having a container which stores the fuel. The heating apparatus comprises a fuel pickup conduit having an inlet, an outlet, and a first portion insertable into the container, the first portion terminating with the inlet. The heating apparatus also comprises a heat exchanging assembly insertable into the container for passing heatable fluid adjacent the first portion of the fuel pickup conduit. Further, the heating apparatus additionally comprises a heating unit including an electrical heating element mounted proximate the fuel pickup conduit and further including a connector for supplying electrical energy to the heating element.

Abstract: A fuel preheating system for an internal combustion engine wherein a preheater includes a body member having defined therein a pair of serially connected, generally parallel bores defining a flow passages through which a flow of fuel may be passed for heating thereof by elongated electric heaters extending within the passages and including a heating element encompassed by helical coils of a heat exchange structure. At least some of the coils of the heat exchange structure define plural tortuous flow paths extending generally axially of the heater.

Abstract: A rigid or dimensionally stable insulating casing or jacket has a surface heating element or superficial heating element connected to the inner surface thereof. This insulating casing or jacket and this superficial heating element conjointly form a sturdy or dimensionally stable preheating body or device for preheating liquids, especially for preheating liquid fuels used for combustion and for powering engines. The inner surface of the preheating body or device provides a substantially close fit, at least in the region of the superficial heating element, for accommodating a chamber or vessel for liquids to be preheated, especially for accommodating a filter pot or bowl for fuel used for powering engines. The preheating body or device is advantageously divided into shell segments which are easily mounted or placed about the chamber or vessel for liquids to be preheated.

Abstract: A fuel heater for vaporization of an alcohol fuel from a fuel line to an internal combustion engine for delivering vaporous fuel to a carburetor. The fuel heater includes a stack of generally planar foraminous PTC heaters that are arranged in a container having an insulated interior defining a fuel flow path having an inlet and an outlet and are separated from each other by generally flat ring-like conductive spacers with electrically conductive ears having conductor receiving holes therein. Alternate conductive spacers are disposed in two channels in a housing and connected to opposite sides of a power supply whereby said PTC heaters can raise the temperature of the incoming fuel and vaporize it. Alternative ears of the electrically conductive spacers are radially offset from each other whereby one row of ears is disposed in one channel and another row is disposed in the other channel.

Abstract: A device for monitoring operational condition of electrical consumers in a motor vehicle, particularly of heater plugs of a diesel engine, includes inductances connected in series between respective heater plugs and their d.c. supply. Alternating or pulsating current is supplied to a connection point of the inductances with the d.c. supply, and potentials across the inductances and the heater plugs are simultaneously evaluated to indicate a defective heater plug.

Abstract: An auxiliary heater controller is provided for use with a liquid cooled engine which includes two fluid circuits. The first fluid circuit includes the engine, a heat exchanger with an air flow creating fan, a heater and a pump, while the second fluid circuit shunts the engine and includes only the heat exchanger, heater and the pump. A single two-way valve operates to direct fluid to either the first or the second fluid circuit, and a timer unit is provided which operates automatically at a preset time to cause fluid to flow in the first fluid circuit for a predetermined time period. The air flow creating fan is operated by a thermostat at low speed when the engine is not operating and is operated by a manually controlled variable speed control unit when the engine is operating.

Abstract: A fuel preheating unit for diesel engines includes a heat exchange coil positioned in a fluid-tight enclosure having an inlet and outlet for a heat exchange medium, such as hot coolant or lubricant from the engine. The coil has a length of at least one foot for each 25 cubic inches of enclosure volume and has ends connected to a diesel fuel inlet and outlet on the enclosure. A spray tube connected to the heat exchange medium inlet extends horizontally below the entire length of the coil and has a plurality of upwardly directed openings for discharge of the heat exchange medium toward the coil for agitation of the medium in the enclosure around and over the coil. The enclosure is provided with an electric heater for heating the heat exchange medium during cold weather to assist in heating the fuel prior to the time the engine reaches operating temperature.

Abstract: An electronic controller for a predetermined temperature coefficient heater provides solid state control of the application of power to the heater. In particular, a positive temperature coefficient glow plug wherein the heater is plated on a ceramic substrate glow plug is controlled by contactless solid state controller. The temperature of the glow plug is sampled by a clock signal and compared with a predetermined temperature value. Pulsed power is supplied to elevate and maintain the temperature of the heater to the predetermined value. In a complete motor vehicle engine wherein one glow plug is used in each cylinder, one glow plug is sampled and controls the remainder of the plugs.

Abstract: An electrically heated fuel pick-up assembly insertable into a motor vehicle fuel tank for defrosting and dewaxing the fuel therein at the fuel pick-up point includes an inner tube substantially coextensive with and disposed within an outer tube in spaced relationship thereto to define therewith a fuel flow passage therebetween. The inner and outer tubes are immersed within the fuel tank and are supported by a base member attached to one end of the outer tube. A flexible PTC resistance strip heater of the type which automatically adjusts its heat output in response to fuel temperature is spirally disposed along the entire length of the passage on ribs secured to the inner tube for heating the fuel flowing through the passage from a fuel inlet in the end of the inner tube opposite the base member to a fuel outelt in the cap member communicating with an engine fuel supply line.

Abstract: An electric resistor element which can be installed on the outer surface of a filter such as the oil or fuel filter of a combustion engine. The electric resistor element is designed especially for improving the cold starting of a combustion engine. It is suited to be employed particularly during the cold seasons, and apart from improving the cold starting, it is also designed for heating the fuel such as diesel oil before feeding it into the engine. In connection to the oil filter, onto its outer surface there is arranged the electric resistor element in such a fashion that the caloric capacity produced therein is conducted as as effectively possible into the oil filter proper and therealong further into the oil contained in the filter. The electric resistor element is formed as a wide and thin tape and attached around the oil filter, preferably in the vicinity of the filter ring between the oil filter and the engine or the like.

Abstract: An apparatus for controlling a power supply to a glow plug for a vehicular internal combustion engine to preheat the glow plug, in which in addition to the conventional power supply circuit to the glow plug which allows the power supply current to flow into the glow plug so as to preheat the glow plug at an earlier stage when an engine key is inserted into an engine key switch apparatus, a cancel circuit is provided which halts the function of the glow plug power supply circuit for a predetermined period of time when a power supply is connected to the glow plug power supply circuit.

Abstract: A temperature compensation injector control system as used in an electronic fuel injection system for motor vehicles utilizes the value of the voltage levels across the coil (18) to determine the coil's (18) temperature. A multiplexer (20) responds to the value of the source of power (14) and the voltage drop across the coil (18) created by a small leakage current to generate digital signals to a microprocessor (10) for modifying injector control signals.

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 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: An adaptive glow plug controller provides a tracking model temperature means for controlling the application of power to one or more glow plugs in response to the present temperature of the glow plugs. Several control circuits control the maximum time that the power is supplied to the glow plugs and the use of the glow plugs at various temperature levels of the environment and/or the engine.

Abstract: A jacket for maintaining or adding heat to a diesel fuel-type fuel filter as fuel passes through the filter in order to decrease the incidence of congealing and avoid problems associated with condensation. The jacket includes a sleeve of thermally insulative material closely surrounding the fuel filter housing. A mounting ring has a base embedded in the jacket and mounting fingers extended axially from the upper edge of the sleeve. The mounting fingers are bendable over the top wall of the fuel filter element housing. Heating means embedded in the sleeve selectively provide heat to the fuel filter housing for transfer to passing diesel-type fuel.

Abstract: The invention relates to a system for conveying fuel, preferably diesel fuel, to an engine, in particular a diesel engine. The invention includes a pipe, at least one filter and a fuel pump. At least one heating element is provided on a portion of the area of the surface of the filter and in the path of the diesel fuel for partially melting paraffin deposits of the fuel on the heated portion of the filter surface. The heating element extends over only a portion of the surface of the filter, for example over 0.02 to 20 percent of said surface relative to a diesel engine power of 36 kW to 4500 kW. The heating element may be controlled in response to fuel flow through the filter, the pressure difference between the downstream and upstream sides of the filter, absolute pressure on the downstream side of the filter, or in response to the temperature difference between the temperature of the fuel at points upstream and downstream of the filter.

Abstract: A self-contained fuel oil heater unit for use with a diesel engine includes a fuel oil manifold having a spin-on cartridge type oil filter with a central fuel oil outlet and peripheral fuel oil inlets. The upper portion of the manifold contains an upwardly open bowl-shaped recess closed by a removable cover and defining a reservoir containing an electric immersion PTC heating element for warming the fuel oil. The unheated fuel oil flows through a horizontally disposed inlet on the lower portion of the manifold into the reservoir where it is heated and is discharged through a passage communicating with the peripheral fuel oil inlets of the filter. A further manifold passage communicates the central fuel oil outlet of the filter to a horizontally disposed outlet on the lower portion of the manifold. Alternatively the heater unit can be formed as a spacer insertable between the manifold and spin-on filter and containing a star-shaped PTC heater.

Abstract: A device connectable in the cooling system of an automobile engine includes a heating chamber through which the engine coolant flows, and which includes a tubular heating coil. The coil is connected between the windshield washer fluid reservoir and the windshield washer nozzle or nozzles of the vehicle. Windshield washer liquid flowing through the coil is warmed by heat exchange with hot engine coolant flowing through the chamber in which the coil is mounted. In a modified arrangement, the device incorporates a second function, in that the chamber is enlarged to include, in addition to the windshield washer fluid heating coil, an electrical heating element which can be connected to house current while the vehicle is parked with its engine not running. The engine coolant is thus heated to keep the engine warm during cold weather by thermal circulation.

Abstract: Apparatus and method for heating liquids, e.g. diesel fuel, by means of a conductive polymer heater which does not have an insulating jacket, so that there is direct physical contact between the liquid and electrically conductive parts of the heater. This results in improved heat transfer to the liquid. The unjacketed heater comprises a pair of elongate spaced electrodes embedded in an elongated strip of a conductive polymer, such as cross-linked polyvinylidene fluoride, which exhibits PTC behavior. The heater is positioned in a container through which diesel fuel to be heated flows from an entry port to an exit port. The exterior surface of the polymer strip is exposed and is directly contacted by the flowing diesel fuel.

Abstract: A self-regulating electric glow plug for an air-compressing internal combustion engine includes an elongated tube having a first end arranged within a plug housing and a second closed end defining a tubular component adapted to extend into a combustion chamber of the engine to produce heat when heated to a glowing condition. A coiled electric resistance heating element is disposed entirely within the tubular component and is embedded in a mass of thermally conductive electrical filling the tube. The resistance element includes two oppositely wound resistance wire coils connected in an end-to-end serially connected array with the first coil being located closest to the glow plug housing and the second coil being located closest to the closed tube end. The first coil has a higher positive temperature coefficient of resistance than the second coil.

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 method for heating diesel prior to filtration by passing the diesel fuel through a heating apparatus including a container having entry and exit ports for the fuel and an elongated electrical heater arranged in spaced apart coils within the container for directing the flow of fuel so that, as the fuel flows from the entry port to the exit port, it flows along an elongate curved path which follows the coils of the heater and which curved path preferably has a length at least eight times the straightline distance between the entry and exit ports. The electric heater is unjacketed and comprises a pair of elongate electrodes embedded in an elongate strip of a conductive polymer composition which exhibits PTC behavior. The exterior surface of the elongate polymer strip is exposed so that it is directly contacted by the diesel fuel flowing through the container.

Abstract: The tips 14 of any glow plugs 10 which are shorted are protected against enlargement by a separate protective device 28 in each series connection 26 to an individual glow plug opening in a fraction of a second in response to current through the device of a value corresponding to a short of the heating element in the tip.

Abstract: A fuel preheater for liquid fuel having a multi-pass heat exchanger for said fuel, heated by an electrical resistance heater provided with a sensor adjacent the device designed to burn the fuel, the sensor controlling the flow of electrical current to said heater. The heat exchanger is preferably made from extruded stock and a material having good heat conductivity. If the device burning the fuel is a water cooled device, a separate heat exchanger using such heated water may be placed in series with the preheater in order to augment it.

Abstract: A preheater unit magnetically attachable to the surface of the oil pan of an automobile engine includes an electric heating unit and a magnetic device situated within a rectilinear shell having an open side closed by a non-magnetic heat transfer plate. The heating unit is encased in the plate and surrounds the magnetic device. The magnetic device includes a permanent magnet disposed between two magnetic end portions situated to be operative in the same plane as the outer planar surface of the plate through parallel spaced apart openings in the plate for magnetically attaching the preheater unit to the surface of the oil pan. A temperature control switch within the shell maintains the heat transfer plate within predetermined temperature limits.

Abstract: An apparatus for controlling the preheating of a diesel engine in which a preheating plug is rapidly brought to starting temperature so that the engine be substantially instantaneously started. Each preheating plug in each of the cylinders of the engine has a heater body having a resistance which varies with temperature changes but which is sufficiently small that the heater body would melt if a predetermined rated voltage were continuously applied thereto. When the starter switch of the engine is in the engine accessory position, so long as the detected temperature of the heater body is below an upper preheating temperature, the rated voltage is applied directly to the heater body. When the temperature of the heater body reaches the upper temperature, the heater body is disconnected from the battery. In the engine starting position of the starter switch, the quick heating circuit is disconnected and the heater body is coupled to the battery through a stabilizer resistor.

Abstract: A heating device for use in motor vehicles to rapidly heat combustion chambers, exhaust gas sensors, catalyzers and other associated apparatus. A resistive heating element is connected in series with a low-impedance measuring resistor and a switch across a power source, while a resistance bridge is formed with the aid of two further resistors. The diagonal bridge voltages are compared in a comparator whose output actuates a control circuit which operates the heater switch. The heater switch also provides the power for the comparator. In a first interval, constant current is applied to the heating element, while the current is pulsed during a second time interval. The switch control pulses may be provided by a free-running oscillator or one whose pulses are synchronized with the undulations of the engine starter current.

Abstract: A combined on-board electric network generator and heater for vehicles, having mounted in its housing an armature which supports at least one alternating current coil and, more particularly, three-phase current coils. The combined generator-heater has a drum-shaped rotor, driven by the engine of the vehicle. The housing of this unit is closed and encloses the rotor as well as the armature and is formed with fluid ducts. Within the housing, a cooling-air circulation is maintained which streams over the coils and rotors and cools them, transferring heat to heat exchange elements which form part of the housing. A cooling fluid circulates in the ducts in a loop through input and output ports. The loop closes upon itself outside of the housing. The cooling fluid circulation recovers heat losses in the generator and makes the heat available for heating the passenger compartment of a vehicle.

Abstract: A portable heater for radiantly heating the underbody, particularly the engine oil pan or crankcase, of a motor vehicle to facilitate starting in cold weather includes an elongate wheeled support member horizontally positionable adjacent and under the vehicle by a handle on one end of the support member. A radiant energy generator, such as a conventional infrared lamp or an electric resistance element, is mounted on the support member and oriented to project a beam of radiant energy substantially parallel to and along the longitudinal axis of the support member to a planar reflector on the support member downstream of the generator and disposed at an angle to reflect the beam of radiant energy upwardly to portion of the vehicle underbody desired to be heated.

Abstract: An electric heater for heating oil contained in the sump well of a compressor includes a thermally conductive shell having first and second opposed inner surfaces. A ceramic core having a D-shaped cross-section throughout is positioned in the shell and is provided with longitudinal channels which are disposed substantially the same distance from the outer curved surface of core. An electric resistance heating element is disposed in the channels and is energizable by a source of power for developing heat under the control of a thermostat disposed in the shell. A resilient pad of ceramic fiberglass material having low thermal conductivity is disposed between the flat surface of the core and the thermostat and urges the curved surface of the core and the thermostat into contact with the opposed inner surfaces of the shell while substantially blocking heat transfer therethrough from the heating element to the thermostat.

Abstract: An electric heater for heating diesel fuel includes a housing having an inlet and an outlet. A flat disk-shaped PTC thermistor is centrally mounted in the housing and is arranged so that the inlet directs fuel against one side of the thermistor to divert the flow of fuel outwardly around the marginal edges of the thermistor. An electrical resistance heater unit surrounds the thermistor between the walls of the housing and the thermistor and is provided with spaces through which the outwardly diverted fuel passes. A divider wall in the housing spaced from the heater unit and thermistor directs the fuel passing through the heater unit across the opposite side of the thermistor to the housing outlet. The PTC thermistor and electric heater unit are connected electrically in series whereby the thermistor functions to control heating output of the fuel heater in accordance with ambient temperature conditions.

Abstract: The apparatus includes an inverter connected with the vehicle battery and/or generator and/or alternator for supplying power at external power source voltage and frequency, a resistance heater positioned adjacent the vehicle fuel tank and/or fuel lines, and a relay connecting the heater to an external power source or to the inverter. The relay is biased to connect the heater with the inverter, and has an actuating coil which connects the heater with the external power source. The actuating coil is connected across the relay terminals which may be connected to the external power source.

Abstract: A starting aid for an internal combustion engine comprises a tubular extension in the end of which is wound an electric heating element. Surrounding the extension is a tubular member which ever at least a substantial portion of its length is mounted on spaced relationship to the extension. The member is formed from heat resistant material and acts to minimize the temperature attained by the extension when the aid is in use.

Abstract: The invention contemplates a continuously circulating pumped flow of diesel-engine fuel, involving thermodynamic coupling to the engine's coolant-circulation system (a) while the engine is operating and (b) involving selectively available thermodynamic coupling to an externally supplied electric-heater element during periods of engine shut-down. To assure fuel circulation during such operation of the heater element, a rectifier taps the external electric supply to provide pump excitation and thus not to drain the charge on the storage battery associated with the engine.

Abstract: A thermostatically controlled electric fuel heater for raising the temperature of diesel fuel flowing from a fuel tank to a fuel filter to prevent precipitation of wax crystals in the fuel filter and consequent filter clogging at low ambient temperatures includes a heat conductive tube incorporated as part of the fuel line a short distance upstream of the filter. An electric heating assembly is positioned on the tube and includes an electric resistance heating element helically wound about the tube and controlled by a thermostat responsive to the temperature of the tube and located upstream from the heating element. The thermostat includes a molded plastic frame having a central opening through which the tube passes. The thermostat includes a bimetallic thermal element secured to the frame and arranged to actuate a snap-action switch carried by the frame. The frame includes a baffle for thermally isolating the thermal element from the heating element.

Abstract: A fuel tank is provided with an electric immersion heating element assembly directly immersible in the fuel within the tank and resting on the curved tank bottom. The assembly includes an elongated, cylindrically shaped, solid aluminum heater body having a longitudinally extending cavity in each end thereof closed by a resilient plastic end cap of larger diameter than the body and secured thereto by a snap fit rib and groove connection. One of the cavities has an inward axial extension in which is received an electric heating element with one end of the heating element electrically connected to the body at the inner end of the extension. An adjustable thermostatic switch is located in the other cavity and is electrically connected in series with the other end of the heating element and with one wire of a flexible power supply conduit extending in sealed relation through the end cap closing the other cavity.

Abstract: A control for modulating the duty cycle of diesel engine glow plugs has two heat sensitive, normally closed switches each thermally coupled to a respective positive temperature coefficient (PTC) of resistivity heater in turn thermally coupled to a common heat sink. The heat sensitive switches are serially connected to each other, to an ignition switch and to a glow plug relay. The PTC heaters are connected to a point between the heat sensitive switches and the relay and to ground. A third PTC heater is disposed on the heat sink intermediate the first and second heaters and thermally coupled to the heat sink. The third heater is connected to an alternator and serves to cut off power to the glow plugs after a selected after glow stage. The two heat sensitive switches can be selected to open at approximately the same temperature for a random operating mode or at slightly different temperatures for a sequential operating mode.

Abstract: The diesel fuel heater is PTC energized and is for heating gelled diesel fuel to a liquid state so as to improve engine performance particularly for engine starting. The heater is compact and is preferably integrated in a fuel filter housing. The heater basically comprises a diesel fuel heater housing and a PTC mounting plate, both of which are mounted in the fuel filter housing over the filter element. A preferably annular fuel flow channel is defined between the heater housing and PTC mounting plate with the diesel fuel adapted to pass directly over the PTC thermistors as the fuel flows from housing inlet to the filter element. A spring biasing contact is disposed intermediate the heater housing and PTC mounting plate to retain the PTC thermistors in place.

Abstract: A diesel fuel filter in which wax crystals that tend to clog the filter at low ambient temperatures are directly heated to melt the crystals, allowing them to pass through the filter. A low energy heating element is positioned adjacent the filter element in the region where wax normally accumulates. The heater melts the wax without significantly raising the temperature of the fuel.

Abstract: A fuel supply system having means for furnishing a mixture of air and alcohol or gasohol fuels to an automotive engine has a self-regulating, ceramic, electrical resistance heater for enhancing fuel evaporation during cold engine starting and incorporates a heater of improved structure to maintain stable heating properties in the alcohol-based system over a long service life.

Abstract: A preheater unit magnetically attachable to the surface of the oil pan of an automobile engine includes an electric heating unit and a magnetic device situated within a rectilinear shell having an open side closed by a non-magnetic heat transfer plate. The heating unit is encased in the plate and surrounds the magnetic device. The magnetic device includes a permanent magnet disposed between two magnetic end portions situated to be operative in the same plane as the outer planar surface of the plate through parallel spaced apart openings in the plate for magnetically attaching the preheater unit to the surface of the oil pan. A temperature control switch within the shell maintains the heat transfer plate within predetermined temperature limits.