Abstract: A clamping jig for mounting semiconductor laser bars includes: multiple supporting bars for holding laser bars therebetween; a pair of supporting plates each of which has a mounting face for mounting the supporting bars in a row; a pressing member for pressing the supporting bars for holding the laser bar; pressing cover members for covering both ends of each supporting bar to prevent supporting bars from falling from the supporting plate; and a supporting frame for detachably supporting the supporting plates and pressing cover members. Each supporting bar is formed with a longitudinal length greater than the laser bar, within a predetermined length so as to be mounted within the supporting frame. Both of the pair of supporting plates may be mounted so as to face one another, or just one may be mounted with the pressing cover members being mounted on the supporting frame instead of the other supporting plate.

Abstract: A method of rotation of a material formation platter and a rotating platter wherein the platter is subjected to a first magnetic field and a second magnetic field at an angle to the first magnetic field, thereby causing the platter to rotate.

Abstract: An apparatus for a semiconductor device includes: a chamber; a susceptor in the chamber; a plurality of heating-blocks on the susceptor; a lift pin assembly through the susceptor; a substrate holder over the susceptor, the substrate holder having a plurality of through holes corresponding to the plurality of heating-blocks; and a shaft combined with the substrate holder-through the susceptor.

Abstract: A substrate handling system and method in which an air chuck produces a film of air between the substrate and the air chuck, a magnetic chuck attracts the substrate to the air chuck, and an actuator subsystem moves the magnetic chuck closer to and away from the air chuck to alternately pick up a substrate and release the substrate.

Abstract: A milking installation comprises a compressed air system with a compressed air line, a pneumatically controllable cylinder and a compressed air pump for supplying compressed air for the cylinder. The compressed air system comprises a dew point sensor for measuring the dew point of the compressed air and for emitting a dew point signal that is representative of the dew point. The milking installation may comprise or form part of a milking robot for automatically connecting teat cups to the teats of a dairy animal.

Abstract: A bird feeder hanger assembly having a pivot member adapted to be pivotably attached to the main body of a bird feeder; the pivot member having engaging means comprising a slot or the like; a hanger member also having engaging means configured to co-operate with the first member engaging means such that when connecting the assembly to the main body of a bird feeder the hanger member can first be pushed into the slot of the pivot member and then pulled along an axis of the slot so that the engaging means of the hanger member and the engaging means of the pivot member mutually engage.

Abstract: A method that accounts for environmental factors by measuring the starch and fiber degradation characteristics of a variety of genetically different crop plants and grain from crop plants in real time to determine how the crop plants should be conserved, processed and blended into a feed formulation that results in optimum productivity of the ruminant animal. A method further including determining starch digestibility characteristics of a set of crop plant samples comprising grain of said crop plant; developing a prediction equation based on said starch digestibility characteristics, obtaining a grain sample from a crop plant, determining in real time starch digestibility characteristics by NIRS of said sample by inputting data from said NIRS into said equation, storing and/or milling said grain on an identity preserved basis, and determining the amount of said crop plant to incorporate into a feed formulation based on the starch digestibility characteristics.

Abstract: A highly automated method and system for providing individual animal electronic identification, measurement and value based management of cattle in a large cattle feedlot. Through the use of (1) a computer system integrated with (2) automatic individual animal identification (3) multiple measurement and remeasurement systems with automatic data input and (4) a cattle handling and sorting system, animals are individually (a) identified and (b) measured by weight, external dimensions and characteristics of internal body tissue. With this information together with animal physiological characteristics and historical data, the computer system calculates the optimum (c) slaughter weight, (d) economic end point and (e) marketing date for shipment to a packing plant. After measurement, individual animals are (f) sorted by direction of the computer in response to calculations from the measurements.

Abstract: This invention is packaging of bird feed as instant bird feeders, comprising seed reservoirs filled by bird seed processors, conveniently operable packaging for the consumer, and bird feeder components including feed trough, perches and means to collect waste hulls and discarded seeds.

Abstract: The present invention relates to a receptacle preferably in form of a trough for feeding domestic animals, comprising one rear wall part, and at least one other wall part, and a bottom part, and suspension means, where said rear wall part and said other wall part are interconnected by curved corner parts, and said suspension means are positioned at an upper part of said rear wall part and are extending outwards from said rear wall part forming a fold back part, and said suspension means are provided with reinforced areas extending along a substantial length of said suspension means, wherein said reinforced areas of said suspension means are provided as a curved continuation of said curved corner parts.

Abstract: An apparatus for animal litter called a Cat Litter Pod. This apparatus features a bottom built-in liner, impervious to liquids; a top gauze-like, cheesecloth material to cover the litter granules; a way to join the top and bottom to provide an encasement space; and absorbent granules of various litter material inside the encasement. This litter pod provides convenience and portability to necessary sanitation devices for cats that are kept inside. Configured as a low profile and disposable this apparatus is particularly important to older or infirm cats that have problems with limited mobility.

Abstract: The present invention relates to an animal litter for using an animal litter box and a litter box using the same. The animal litter can suppress odors generated from animal excrement evacuated on the animal litter. The animal litter is comprised of a mass of grains having a peculiar liquid passing property whereby most part of liquid poured onto the grains is not held in the grains but passed through them meanwhile other part of liquid remained in the grains is absorbed into the grains. More concretely, the maximum absorbable amount of liquid of a grain is 3 to 4.0 times the weight of the grain, the amount of liquid absorbed by a grain per three seconds is 20 to 70% of the maximum absorbable amount of liquid absorbed by the each grain; and a liquid passing ratio of the mass of grains is 70% or greater.

Abstract: To provide a discharged waste processing material for pet animals, which can be obtained by using a waste material as represented by a beverage pack and which has a high urine absorbing property and a high urine retaining property. A discharged waste processing material for pet animals comprising a waste material of double sided water resistant paper used as a raw material, the double sided water resistant paper having a laminate layer of a water resistant film formed on each of double surfaces thereof, a crushed paper piece 2? used as a chief material, the crushed paper piece 2? being obtained by finely crushing the double sided water resistant paper and having the laminate layer 5?, 6? formed on each of double surfaces thereof, a granular body 7 formed of an aggregate of the crushed paper pieces 2?.

Abstract: A cat litter product is provided and includes manufacture primarily from modified corn starch which is processed through mash distillation. The litter product is pelletized via an extrusion technology process so as to form particles the size of wheat grain. The litter product provides, collectively, a non-toxic and naturally safe, biodegradable, odor-eliminating, scented, anti-bacterial litter that clumps in a convenient size for easy disposal and which has little dust and reduces tracking by cats.

Abstract: A device (10) for repelling selected aquatic creatures, such as sharks. The device consists of an electromagnetic field generator (21, 30) for generating an electromagnetic field (50) that repels sharks and is supported by a buoyant device (20). This provides a shark-free region about the device (10). Multiple devices can be connected together to form an array of repelling devices, thereby extending the shark-free region.

Abstract: The invention comprises an apparatus for mixing and dispensing shampoo solutions for use with pets and other animals. The apparatus includes a primary reservoir, a pump in communication with the reservoir, a nozzle in communication with the pump, and related controls. Water and a predetermined amount of shampoo concentrate are put into the reservoir and mixed as explained in further detail in; the enclosed materials. Once mixed, the controls are reset to enable the solution to be dispensed as an aerated foam from a nozzle.

Abstract: A pet grooming tool, for use with a furry pet such as a dog or cat having loose hair and non-loose hair, is adapted for removing the loose hair from the pet. The grooming tool comprises an elongate handle portion extending generally along a handle axis, and a pet engageable portion secured to the handle portion. The pet engageable portion includes a blade portion and a plurality of teeth. The blade portion includes a blade edge. The teeth extend from the blade edge. The pet engageable portion is secured to the handle portion in a manner so that pulling the handle portion generally along the handle axis while the pet engageable portion is in engagement with the pet causes the blade portion to engage the loose hair of the pet and pull it from the pet without cutting or pulling the non-loose hair from the pet.

Abstract: A wireless fencing system comprises a tetherless leash, a programming fixture, and, optionally, a terminal. The tetherless leash, which is attached to an animal that is to be monitored, establishes a “virtual” (i.e., barrier-free) perimeter based on geo-coordinates. The tetherless leash also monitors the position and movement of an animal relative to the perimeter, and delivers warnings, corrections, and praise to the animal in accordance with its programming. The programming fixture serves as a user interface during programming operations, since there are no exposed buttons by which a user can directly program the tetherless leash.

Abstract: A wireless fencing system comprises a tetherless leash, a programming fixture, and, optionally, a terminal. The tetherless leash, which is attached to an animal that is to be monitored, establishes a “virtual” (i.e., barrier-free) perimeter based on geo-coordinates. The tetherless leash also monitors the position and movement of an animal relative to the perimeter, and delivers warnings, corrections, and praise to the animal in accordance with its programming. The programming fixture serves as a user interface during programming operations, since there are no exposed buttons by which a user can directly program the tetherless leash.

Abstract: A significantly improved leash has a strap or belt with a carabiner at a lower end and a loop at an upper end. The loop may be a preconfigured holding loop or it may be an adjustable loop that can be adjusted by clipping a carabiner into eyelets in the leash. The leash permits even an animal that is pulling strongly on the leash to be held in check, by a hand grip disposed in the holding loop, or adjacent to the holding loop.

Abstract: A gas fed water-heater has a double wall container (1) inside of which are arranged a burner (2) and a tank (3) of the water to be heated. At least in the portion (5?) adjacent to the burner (2) of the interspace (5) between the two walls of the container (1), a thermoinsulating system is placed comprising an inner layer (6) of glass wool or rock wool and an outer layer (7) formed of at least one vacuum panel, which is formed by an envelope which encloses inert material powder having an average particle size of less than 100 nanometers.

Abstract: Electrical components projecting outwardly from the storage tank portion of an electric water heater are shielded from foam insulation material being injected into an insulation space between the tank and an outer jacket portion of the water heater by a hollow, open sided foam dam structure extending through a jacket opening and circumscribing the electrical components. Force exerting projections on the dam engage the interior side surface of the jacket and forcibly hold the inner side of the dam structure in sealing engagement with the tank. The projections also hold an outer side peripheral lip of the dam in a an outwardly and resiliently deflected orientation in which it is sealingly pressed inwardly against the outer side surface of the jacket around the periphery of the opening therein to prevent injected foam from being forced outwardly through the jacket opening.

Abstract: The system for managing the heat energy developed by a heat engine (10) of a motor vehicle comprises a main system (2) equipped with a main pump (12), a heat engine (10) and a main cooling radiator (18). The main system (2) furthermore comprises a short-circuit pipeline (20) and a heating pipeline (22) comprising an air heater (24), and a secondary loop (4) including a secondary radiator (60) and a secondary pump (58). The main system and the secondary loop can comprise equipments heated or cooled by equipment exchangers (34, 36, 38, 64, 66) included in the main system (2) and/or the secondary loop (4). The maim system (2) and the secondary loop (4) are connected by interconnecting means which make it possible to cause a same coolant fluid to circulate in a controlled manner between the main system and the secondary loop or to prohibit this circulation depending on the load state of the engine (10).

Abstract: Oil jets are mounted in upper two cylinders in a cylinder block of a 4-cylinder vertical engine to inject an oil to rear faces of pistons received in the two cylinders. Thus, although lower pistons are cooled more effectively by the oil dropped by gravitation through oil return bores provided in journal support walls, the upper pistons are forcibly cooled by the oil injected from the oil jets, so that the four pistons can be cooled equally to prevent insufficient cooling and excessive cooling, while minimizing the required amount of the oil.

Abstract: A moveable crankshaft assembly that is positioned by an hydraulic positioning device hydraulically connected to a constant pressure hydraulic reservoir. The hydraulic connections between the reservoir and the positioning device are equipped with pressure relief valves, or equivalent substitutes, connected in parallel to pass fluid in either direction to maintain the same pressure in the hydraulic positioning device as in the reservoir. A coupling is installed between the crankshaft and the power train that is capable of accommodating movement.

Abstract: A system and method is disclosed for supplying hydraulic fluid to a lost motion system in an internal combustion engine. The system may comprise a reservoir; a gallery circuit connected to the reservoir, wherein the gallery circuit is adapted to be connected to the one or more lost motion systems; and a control valve adapted to provide selective hydraulic communication between the gallery circuit and the one or more lost motion systems.

Abstract: A valve actuator for actuating a gas exchange valve of an internal combustion engine, having a sleeve-shaped positioning piston, which is connected to a valve shaft, having at least two shell-shaped wedge parts, enclosing a shaft end of the valve shaft, on whose radial outer peripheral surface a section shaped like a conical casing is implemented and which are axially connected on their inner side to the shaft end in a form-locked and rotatable manner, the valve actuator having a separate threaded sleeve, which has a threaded connection to the positioning piston or a component connected to the positioning piston and also axially clamps the wedge parts to a conical clamp sleeve via their section shaped like a conical casing.

Abstract: Low load operating point for a controlled auto-ignition four-stroke internal combustion engine is reduced without compromising combustion stability through a valve control operative to establish sub-atmospheric pressure conditions within the combustion chamber into which fuel and exhaust gases are introduced.

Abstract: An FI/AT/MGECU, in a cylinders deactivation operating state during cruise control where the vehicle speed follows a predetermined target speed, regulates renewal on an addition side of a power plant required torque final value TQPPRQF, and in a case where a flag value of a torque hold flag F_CCKTQS showing to hold the power plant required torque final value TQPPRQF to a predetermined torque value related to a cylinder deactivation upper limit torque TQACS is a “1” (YES side in step S33), when the vehicle speed VP is decreased less than a value obtained by subtracting from a set vehicle speed VC which it the target vehicle speed during cruise control, a predetermined vehicle speed #?V (for example, #?V=3 km/h or the like) (YES side in step S35), the internal-combustion engine E is switched from a cylinders deactivation operation to an all cylinders operation. The fuel consumption efficiency is thus improved while keeping occupants in the vehicle from feeling discomfort with respect to travelling behavior.

Abstract: A control system for an internal combustion engine, which is capable of reducing exhaust emissions during and after the start of the engine. A control system is capable of changing the valve-closing timing of intake valves relative to the valve-opening timing thereof as desired using a variable intake valve actuation assembly. The control system includes an ECU. The ECU sets a target auxiliary intake cam phase to a start value that sets the valve-closing timing of the intake valves to retarded-closing timing, during starting of the engine, and to a catalyst warmup value that sets the same to timing closer to timing in the Otto cycle operation, during catalyst warmup control after the start of the engine.

Abstract: An object is to improve fuel consumption efficiency. Accordingly, a fuel gradual addition delay time when starting (engine water temperature) TMKSTDLYT which changes in a decreasing trend with an increase in the engine water temperature is set (step S10). A fuel gradual addition delay time when starting (state of charge) TMKSTDLYQ which changes in an increasing trend with an increase in the state of charge QBAT is set (step S12 and S14). A fuel gradual addition delay time when starting (vehicle speed) TMKSTDLYV which changes in a decreasing trend with an increase in vehicle speed VP is set (step S13 and S15). Then the greatest value of; the fuel gradual addition delay time when starting (engine water temperature) TMKSTDLYT, the fuel gradual addition delay time when starting (state of charge) TMKSTDLYQ, and the fuel gradual addition delay time when starting (vehicle speed) TMKSTDLYV is set as a fuel gradual addition delay time when starting TMKSTDLY (step S16).

Abstract: A unit carrier for secondary units of a motor vehicle internal combustion engine, having secondary unit attachment devices and engine block attachment devices. The unit carrier has a planned deformation point, which allows a relative displacement between the secondary unit and the engine block in case of a vehicle collision, if a predefined force is exceeded. The unit carrier is used in motor vehicles having a front engine arrangement.

Abstract: A balanced rotary cycling machine suitable for use as an internal combustion engine, compressed gas or steam engine, compressor or pump is disclosed herein. The rotor assembly consists of four articulating pistons where the opposite pistons are inter-linked with each other by pivoted rods comprising a parallelogram mechanism and therefore eliminating a need for pivots between pistons. The rotor assembly rotates inside or outside of a circular or non-circular stator depending on the configuration chosen. A variety of mechanisms for shape deformation of four piston assembly during its rotating cycle is also disclosed herein, as well as detailed descriptions of preferred embodiments, including a four cycle internal combustion engine with circular stator, marine engine with polymer parts and a four cycle automobile rotary engine with conventional oil pan. In addition, a method of operation of external rotary combustion engine, employing a high-pressure compressor and an external combustion chamber, is disclosed.

Abstract: The present spark plug is of the encapsulated design and facilitates the life of the spark plug, enhances the combustion process and reduces emissions. The position of the spark plug is substantially within a cylinder head external of a combustion chamber of an engine and close to a cooling passage which reduces the heat transferred to the spark plug and increases the life of the spark plug. The configuration or design of the spark plug makes the manufacturing process less costly and facilitates the combustion process by using one of a single orifice or a plurality of orifices positioned at and in a preestablished manner. The configuration will reduce or eliminate pre-ignition and other detonation problems enabling the timing to be advanced further reducing emissions.

Abstract: Low load operating point for a direct-injection controlled auto-ignition four-stroke internal combustion engine is reduced without compromising combustion stability through a split-injection control operative to introduce a first fuel fraction, air and exhaust gases into the combustion chamber during an intake event and a second fuel fraction into the combustion chamber during a compression event.

Abstract: Disclosed is an internal combustion engine in which it is possible to provide, from the exhaust stroke to the intake stroke, a period T during which both an intake valve (14) and an exhaust valve (15) remain closed, the internal combustion engine being equipped with a fuel injection valve (24) capable of injecting fuel into a combustion chamber (16), the closing time EVC for the exhaust valve (15) being set to be on the advance side with respect to the intake top dead center, the fuel injected from the fuel injection valve (24) being pressurized together with a residual gas inside the combustion chamber (16) during the period T in which both the intake valve (14) and the exhaust valve (15) remain closed.

Abstract: The structure and method of controlling engine fuel-air mixing for internal combustion engine applications, comprising utilizing a fuel injection module and incorporating therein a plurality of aerodynamically shaped vanes which impart vorticities to the incoming air in directions and durations to cause intimate mixing of the fuel and air. This module is readily structurally adaptable for mounting in the air intake system of practically any internal combustion engine.

Abstract: An intake valve device includes a throttle body defining a bore for the flow of intake air. A throttle shaft is rotatably mounted to the throttle body. A slit is formed in the throttle shaft in a diametrical direction and extends throughout the diameter of the throttle shaft. The slit has opposing end walls along the rotational axis of the throttle shaft. A throttle valve is inserted into the slit of the throttle shaft and fixed in position relative to the throttle shaft. Possible intake air leakage channels are defined between the outer periphery of the throttle valve and the end walls of the slit. At least one restriction portion is formed on the throttle valve so as to extend into at least one of the possible leakage channels in order to narrow the possible leakage channel and reduce or inhibit the leakage of intake air.

Abstract: A control apparatus for controlling an internal combustion engine includes a flow rate sensor that detects an intake air flow rate that represents a flow rate of air admitted into a combustion chamber of the internal combustion engine, a pressure sensor that detects a pressure of the air admitted into the combustion chamber of the internal combustion engine, a characteristic change estimation unit that estimates a characteristic change in the internal combustion engine in accordance with the intake air flow rate detected by the flow rate sensor and the intake air pressure detected by the pressure sensor, and a control unit capable of correcting a control amount of the internal combustion engine so as to compensate the characteristic change thereof in accordance with an estimation performed by the characteristic change estimation unit.

Abstract: A fuel feed device of a gas engine of non-supercheged type for feeding air and fuel to an intake port without mixing by amixer, wherein fuel gas is fed into the intake port by utilizing a negative pressure generated in the intake port in an intake stroke.

Abstract: The invention relates to an adjustment device (1) for an internal combustion engine, particularly for adjustment of shafts with adjusting members. Heretofore known open/close switches are relatively large and cost-intensive in their production. For this reason, an adjustment device (1) is proposed, in which a set of gears (5) simply comprising a worm (7) and a partial ring worm gear (8) wherein pin magnets are disposed on the partial ring worm gear. The pin magnets (11) work functionally together with a non-moving switch (16) disposed in a housing (2,3) when a signal is produced by means of the magnetic field of the magnets (11) passing by the switch (16), which stops motor (4) and, as the case may be, predetermines a direction change. Thus, a right/left movement of the motor (4), along with a timely turning off of the motor can be achieved with only one external control signal.

Abstract: A variable valve timing controller includes an intake-valve and an exhaust-valve. When the engine is started, the intake-valve and the exhaust-valve are operated in a first mode in which the exhaust-valve is closed before top dead center and then the intake-valve is opened. And if a first predetermined condition is met, the intake-valve and the exhaust-valve are operated in a second mode in which the opening time of the intake-valve in the first mode is advanced before top dead center.

Abstract: A fuel injection system for an internal combustion engine comprises a nozzle (2) with an inlet and a cam-driven plunger (5) forming a plunger chamber (7) which is connected to the inlet of the nozzle. The injection system also comprises a common rail (10) for fuel and a control valve (9) installed between the plunger chamber (7) and the common rail (10), wherein the control valve is able to open or close hydraulic communication between the plunger chamber and the common rail upon receiving an electrical control command. An electrically actuated nozzle control valve (21) is used for opening and closing of the nozzle (2). The system also comprises a means (11) for pressurizing the common rail and regulating pressure of the fuel in the common rail (10).

Abstract: The invention relates to a starting system (1) for an internal combustion engine comprising pressurized fuel supply means (3), an accumulator means (2), which is supplied with pressurized fuel by said supply means, and at least one injection means (4) which is supplied with fuel by the accumulator means (2). According to the invention, the system also comprises a device for storing pressurized fuel (5), which is supplied due to the pressure in the accumulator means. At start-up, the aforementioned fuel storage device can supply the stored fuel in such a way as to provide a second fuel compression means which enables the engine to start up more rapidly. The invention is particularly suitable for use in the area of common-rail engines.

Abstract: With a low-pressure pump, fuel is supplied to a vapor separator comprising an air discharge port and a ball valve for closing the air discharge port in association with a rise in fluid level of the fuel supplied to the vapor separator. When the fuel is filled into the vapor separator entirely, the ball valve acts to tightly close the vapor separator, thereby pressurizing the fuel in the vapor separator.

Abstract: An improved crankcase ventilation system for a vehicle which includes an air compressor to route crankcase gases to the intake manifold for combustion. The primary vehicle components include and aircleaner, a turbocharger compressor positioned downstream from the aircleaner, an optional aftercooler positioned downstream from the turbocharger compressor, and an engine having an intake manifold and a crankcase equipped with a breather port for venting crankcase gases. Crankcase gases are vented through the breather port to the air compressor. Clean air from downstream of the aircleaner but upstream of the turbocharger compressor is drawn into the air compressor as needed to prevent the air compressor from drawing too much crankcase gas and reducing the internal pressure of the crankcase to undesirable levels.

Abstract: According to the invention, an EGR control apparatus of an engine includes intake ports to which an intake passage is connected, the intake ports opening into each combustion chamber of the engine, an EGR port to which an EGR passage branching out from an exhaust passage is connected, the EGR port opening into each combustion chamber of the engine, an electrically-operated compressor disposed in the EGR passage for regulating pressure at which EGR gas is introduced into each combustion chamber, and an EGR control valve disposed in the EGR passage at a point downstream of the electrically-operated compressor for controlling the amount of EGR gas introduced into each combustion chamber. The EGR passage branches out from the exhaust passage at a point downstream of an emission control device disposed in the exhaust passage.

Abstract: Method and arrangement for delivering EGR gas to combustion spaces in a multi-cylinder, four-stroke internal combustion engine. Each cylinder, with an associated piston, has at least one inlet valve and at least one exhaust valve (10) for controlling fluid interconnection between the combustion space in the cylinder and an intake system and an exhaust system, respectively. A rotatable camshaft (18) having a cam curve (23) is designed to interact with a cam follower (17) for operation of the exhaust valve (10) during a first opening and closing phase. The cam curve (23) is also designed to interact with a second cam follower (20) during a second opening and closing phase which is phase-offset in relation to the first aforementioned opening and closing phase. This configuration facilitates the cylinder being connected to the exhaust system during the induction stroke, once the exhaust stroke is completed.

Abstract: Devices for modifying engine valve lift during an engine valve event are disclosed. In one embodiment, the device comprises: a housing having a hydraulic fluid dump port formed therein; a sleeve slidably disposed in a bore formed in the housing, the sleeve having a cavity formed therein; a piston slidably disposed in the sleeve cavity; and a clip passage formed in the piston, the clip passage in selective communication with the dump port.

Abstract: An internal combustion engine includes a cylinder with a spark plug, an electric DC voltage supply, and an ignition circuit. The ignition circuit includes a switching device and a transformer having a primary winding coupled to the supply via the switching device, and a secondary winding coupled to the spark plug. After having generated an initial breakdown of a breakdown path through a gas mixture between electrodes of the spark plug, switching occurs repeatedly per combustion to produce pulses at the primary winding, with a repeat frequency which is at least sufficiently high that the breakdown path remains conductive between consecutive switches per combustion. The switching on and switching off provides heating of the breakdown path to ignite the gas mixture. The transformer has an air core around which the primary and secondary windings are arranged concentrically.