Abstract: A plasma jet spark plug for igniting an air-fuel mixture in a conventional combustion device such as an internal combustion engine.

Abstract: A plasma jet ignition plug having high ignition performance and high durability. The plasma jet ignition plug comprises a center electrode wherein at least a front end portion including a front end surface of the center electrode contains an oxide of at least one of the rare earth elements in a total amount of 0.5% by mass to 10% by mass inclusive and tungsten (W) in an amount of 90% by mass or greater, or contains iridium (Ir) in an amount of 0.3% by mass to 3% by mass inclusive and W in an amount of 97% by mass or greater.

Abstract: A plasma jet ignition plug including an insulator having an axial hole extending therethrough in the direction of an axis CL1, a center electrode inserted into the axial hole, and a ground electrode disposed frontward of the front end of the insulator. The insulator has a cavity defined by the wall surface of the axial hole and the front end surface of the center electrode and opens frontward. The ground electrode has a through hole for establishing communication between the cavity and an ambient atmosphere. A front end portion of the center electrode is formed into a taper portion whose diameter reduces frontward in the direction of the axis CL1. The outside diameter of a front end of the taper portion is smaller than the diameter of the through hole. The cavity has a substantially constant diameter with respect to the direction of the axis CL1.

Abstract: A spark plug having a center electrode; an insulator having an axial hole extending in the direction of an axis; a metallic shell; a ground electrode extending from a front end portion of the metallic shell; a center-electrode-side noble metal chip joined to a distal end surface of the center electrode; and a ground-electrode-side noble metal chip joined to a distal end surface of the ground electrode, the ground-electrode-side noble metal chip having a distal end surface facing toward a side surface portion of the center-electrode-side noble metal chip, and the ground electrode being bent at an angle that falls within a range of 120° to 140° inclusive.

Abstract: A urea sensor includes a detecting portion which, in use, is immersed in a liquid accommodated in a urea solution tank for detecting the thermal conductivity of the liquid to detect whether the liquid accommodated in the urea solution tank is an aqueous urea solution; and an enclosing member enclosing a periphery of the detecting portion and including one or more vents penetrating the enclosing member. At least one of the vents is a lower vent being of a configuration and size such that a first hypothetical circle having a diameter of not less than 3.5 mm can be wholly contained within the lower vent. At least a portion of the lower vent is positioned below the detecting portion when the urea sensor is positioned for installation in the urea solution tank.

Abstract: A sensor for detecting a state of liquid contained in a container comprising an outer tubular electrode made of an electrically conductive material, an inner electrode made of an electrically conductive material and disposed concentrically within the outer tubular electrode, a base end support member supporting base end portions of the outer tubular electrode and the inner electrode in a way as to provide insulation therebetween, and a leading end support member elastically supporting a leading end portion of the inner electrode on an inside of a leading end portion of the outer tubular electrode.

Abstract: An ignition apparatus for an ignition plug which uses a positive polarity power supply, which can cause the ignition plug to generate spark discharge while using its center electrode as a negative electrode, and which can adjust the timing of supply of electric energy to the ignition plug and the timing of charging of capacitors. The ignition apparatus is adapted to cause the ignition plug to generate spark discharge while using its center electrode as a negative electrode, and includes a positive power supply, and energy supply units. Each energy supply unit includes a capacitor connected at one end to the power supply and connected at the other end to the ignition plug; a switching unit for charging; and a switching unit for energy supply.

Abstract: A current of sufficient size to form plasma at ignition of a plasma jet ignition plug flows to a spark discharge gap while suppressing noise occurrence. There is provided an ignition apparatus of a plasma jet ignition plug, which includes a resistor R1, with one end connected to a diode D1 disposed between the plasma jet ignition plug 100 and a high-voltage generation circuit 210 and with the other end electrically connected to a center electrode 40 of the plasma jet ignition plug 100, and a capacitor C1, with one end connected to the center electrode 40 of the plasma jet ignition plug 100 and with the other end grounded.

Abstract: A plasma jet ignition plug capable of inhibiting occurrence of channeling while reducing removal of energy of plasma through a ground electrode at the time of emission of plasma. A ground electrode of a plasma jet ignition plug projects inward from a front end face of a metallic shell toward an opening end of a cavity which is open at a front end face of an insulator. A projecting distal end which forms a spark discharge gap between the same and a center electrode within a cavity is located inward, with respect to a diametral direction P orthogonal to an axis O, of a position which is located 0.5 mm radially outward from the opening end of the cavity.

Abstract: A plasma jet spark plug capable of preventing a channeling progress and having excellent heat conduction. The plasma jet spark plug comprised of: a ceramic insulator having a small diameter portion which assumes a linear shape in an axial direction, and a center electrode has an outer diameter increasing in the order of a frontmost portion, a step portion, a front end portion and a body portion.

Abstract: A plasma jet ignition plug having high ignition performance and high durability. The plasma jet ignition plug comprises a center electrode wherein at least a front end portion including a front end surface of the center electrode contains an oxide of at least one of the rare earth elements in a total amount of 0.5% by mass to 10% by mass inclusive and tungsten (W) in an amount of 90% by mass or greater, or contains iridium (Ir) in an amount of 0.3% by mass to 3% by mass inclusive and W in an amount of 97% by mass or greater.

Abstract: A plasma jet ignition plug including an insulator having an axial hole extending therethrough in the direction of an axis CL1, a center electrode inserted into the axial hole, and a ground electrode disposed frontward of the front end of the insulator. The insulator has a cavity defined by the wall surface of the axial hole and the front end surface of the center electrode and opens frontward. The ground electrode has a through hole for establishing communication between the cavity and an ambient atmosphere. A front end portion of the center electrode is formed into a taper portion whose diameter reduces frontward in the direction of the axis CL1. The outside diameter of a front end of the taper portion is smaller than the diameter of the through hole. The cavity has a substantially constant diameter with respect to the direction of the axis CL1.

Abstract: A liquid state detecting apparatus including a detecting element having a heating resistor which generates heat when energized and being disposed in a liquid container for containing a liquid, the apparatus calculating a first difference between a first corresponding value corresponding to a first resistance of the heating resistor acquired after energization of the heating resistor is started and a second corresponding value corresponding to a second resistance of the heating resistor acquired after the heating resistor is energized for a predetermined detection time and obtaining a first concentration of a particular component included in the liquid, the first concentration being associated with the first difference, the apparatus including: an abnormality determination unit, a determination concentration acquiring unit, a concentration difference calculation unit, and a static state determination unit, all as defined herein.

Abstract: A plasma jet spark plug for igniting an air-fuel mixture in a conventional combustion device such as an internal combustion engine.

Abstract: A liquid state detecting sensor for detecting a state of a liquid including a liquid concentration detecting element, a holder member, and an enclosing member as defined herein, wherein the holder member has a configuration in which respective portions of a lower end surface facing the enclosed region are located higher than or at a same height as a lowest hole periphery at the rim of the element holding hole from which the detecting element protrudes, and at least one of circulation holes formed in the enclosing member is a bubble-discharging hole which has an upper end located higher than the lowest hole periphery and a lower end located lower than a surface peripheral edge of the lower end surface.

Abstract: An ignition device for a plasma jet ignition plug is provided. A resistance for decreasing electric noises is not incorporated in a plasma jet ignition plug. A resistance of not less than 1K? and not more than 20K? is provided to a path from a spark discharge circuit to a center electrode, thus reducing the generation of electric noises at the time of trigger discharge. Along with the reduction of the generation of electric noises, a loss of energy at the time of plasma discharge can be reduced by setting an inner resistance provided to a line extending to the center electrode from a plasma discharge circuit to 1? or less. Accordingly, the plasma jet ignition plug can jet flame-shaped plasma sufficiently large for igniting an air-fuel mixture.

Abstract: A plasma jet ignition plug including a wire-wound resistor for restraining the radiation of noise while allowing application of a sufficiently large current for generation of plasma to a spark discharge gap at the time of ignition. The wire-wound resistor having an inductance of 1 ?H to 100 ?H inclusive and a resistance of 1? or less, and is provided on at least one of a center electrode and a ground electrode. The wire-wound resistor restrains current which is generated by the influence of stray capacitance present in the plasma jet ignition plug, thereby reducing noise.

Abstract: A liquid-condition detection sensor (1) including a sensor element (51), at least a portion of which contacts a urea aqueous solution; connection terminals (52) fixedly attached to the sensor element (51); connection cables (53) which electrically communicate with the concentration sensor element (51) via the connection terminals (52); an inner tube (42) which holds the concentration sensor element (51) at a distal end portion (421) by use of a holder member (55) and surrounds a portion of the connection cables (53) and the entire connection terminals (52); and a separator formed from a material having rubberlike elasticity (54) including a terminal-inner-tube-insulating portion (542) which intervenes between the connection terminals (52) and the inner tube (42) to thereby insulate the connection terminals (52) and the inner rube (42) from one another.

Abstract: A control system for controlling the ignition of a plasma-jet spark plug provided in an internal combustion engine senses an operating condition of the internal combustion engine, and determines an ignition mode of the plasma-jet spark plug in accordance with the sensed operating condition. The control system performs an ignition control of breaking down the insulation across a spark discharge gap by applying a first electric power to the plasma-jet spark plug, and producing plasma in the vicinity of the spark discharge gap by applying a second electric power to the spark discharge gap in a state of dielectric breakdown. The control system performs this ignition control according to the ignition mode determined as mentioned above.

Abstract: A liquid state detecting sensor is provided in which a level detecting unit for detecting the level of a liquid and a concentration detecting unit for detecting the concentration of a particular component contained in the liquid are integrated. In a liquid state detecting sensor 100 capable of measuring the level and a urea concentration of a urea aqueous solution, a level detecting unit 70 and a liquid property detecting unit 30 are connected in an insulated state. An outer cylinder electrode 10 and an inner electrode 20 for forming the level detecting unit 70 form a capacitor, and level detection is performed on the basis of the electrostatic capacity which changes in response to the level of the urea aqueous solution which is present therebetween. A holder 120 for holding a ceramic heater 110 is fitted to a leading end portion 21 of the inner electrode 20, and the holder 120 is supported inside a leading end portion 11 of the outer cylinder electrode 10 by a rubber bushing 80.