摘要:
Anti-reducing semiconducting porcelain having a positive temperature coefficient of resistance comprises a barium titanate composition, and a flux containing 0.14 to 2.88 parts by weight of TiO.sub.2 0.1 to 1.6 parts by weight of Al.sub.2 O.sub.3 and 0.1 to 1.6 parts by weight of SiO.sub.2 per 100 parts by weight of the barium titanate composition. It has a high positive temperature coefficient of resistance which does not show any appreciable change in the presence of a reducing atmosphere, such as hydrogen gas or gasified gasoline. It need not be isolated from a reducing atmosphere by a plastic or metallic enclosure, but can be exposed thereto. The flux may further contain a zinc, potassium or lithium compound.
摘要:
A self-temperature controlling type heating device comprises a positive temperature coefficient ceramic resistor having a thin layer portion, a first electrode provided on one face of the thin layer portion, a second electrode provided on the other face of the thin layer portion opposite to the first electrode, and at least one third electrode provided on the surface of the PTC ceramic resistor in spaced relation to the first electrode. An electric current is allowed to flow between the first and second electrodes to form a heating element, and an electric resistance value between the first and third electrodes is detected to thereby make a temperature control. Thus, a high output is obtained at a low voltage and the control temperature is freely varied.
摘要:
A positive ceramic semiconductor device having positive temperature coefficient of resistance comprises a pair of electrodes provided on a ceramic semiconductor substrate. One of the paired electrodes which is to serve as the positive pole is basically constituted by at least an electrically conductive layer of silver-palladium series containing silver and palladium at a predetermined ratio. For preventing a localized current concentration from occurring in the current conducting state, improvement is made as the structure of the positive pole electrode ormed of the electrically conductive material of silver-palladium series and/or the structure of the negative pole electrode. Silver-migration phenomenon on the positive ceramic semiconductor substrate as well as degradation of the mechanical strength thereof is positively prevented.
摘要:
An air heater for heating intake air for an internal combustion engine only in cold start or further warming up operation, having a frame which defines an opening for passing air therethrough, and at least one heater element in the shape of a perforated plate such as a lattice or honeycomb plate supported by the frame so as to traverse only a part of the opening area of the air passage opening, while leaving a substantial part of the opening area free as untraversed by the heater element.
摘要:
An oxygen concentration sensing apparatus in which a block of an oxygen-ion conductive solid electrolyte is interposed between a first electrode and a second electrode disposed opposite to each other. The first electrode is made of a catalytic metal and is exposed at a portion thereof on a surface of the solid electrolyte block, and an electrical insulating heat-resistive layer having a plurality of communication pores covers the exposed portion of the first electrode. The second electrode is porous and made of a catalytic metal. The solid electrolyte is wholly exposed to a stream of gases containing oxygen whose concentration is to be measured, and during measurement, a current source supplies continuously an electric current in a direction from the first electrode toward the second electrode. When the partial pressure of oxygen gas produced at the first electrode and existing in the vicinity thereof exceeds a predetermined value, the excess pressure portion of oxygen gas is discharged into the stream of gases through the communication pores of the heat-resistive layer thereby maintaining substantially constant the partial pressure of oxygen gas in the vicinity of the first electrode. An electromotive force representing the ratio between the partial pressure of oxygen around the first electrode and that in the stream of gases containing oxygen is measured to determine the concentration of oxygen contained in the gases.
摘要:
In an oxygen concentration sensing apparatus comprising a solid, oxygen ion conductive, electrolyte and intervening between two electrodes to generate across the two electrodes a potential difference due to a difference in oxygen concentrations at the boundaries between the two electrodes and the solid electrolyte, one of the two electrodes is made of a metal performing catalytic action, one end portion of the one electrode is embedded in the solid electrolyte to be fixed thereby, the other end portion of the one electrode projects outwardly of the solid electrolyte, a portion of the one electrode contacting with an outer surface of the solid electrolyte is hermetically sealed with a nonconductive layer of a heat-resistant material, and the other electrode is made of a porous metal performing catalytic action and is disposed on the outer surface of the solid electrolyte but preventing the other electrode from being in contact with the one electrode.Further, the oxygen concentration sensing apparatus may be provided with an electric circuit for making an electric current flow intermittently from the one electrode through the solid electrolyte to the other electrode thereby to maintain the oxygen concentration at the boundary between the one electrode and the solid electrolyte at a constant level.
摘要:
An oxygen concentration detector has a detecting element comprising a solid electrolyte inserted into a housing and heating means for heating the detecting element, and the outer surface of the detecting element is provided with a surface layer, the contact angle of the surface layer being larger than the contact angle of the outer surface of the detecting element with which the surface layer directly contacts.
摘要:
A lead wire for a sensor has a conductor unit including at least stainless steel wires and copper wires. By setting the cross-sectional percentage of the stainless steel wires in the conductor unit within the range of 30 to 70%, it is possible to obtain a lead wire having low electrical resistance, and high flexibility, tensile strength and elasticity. There are preferred values in hardness and heat treatment of the stainless steel wires. The copper wires are preferably coated with an antioxidant film. The lead wire may include hybrid wires stranded together and obtained by integrally molding or forming stainless steel and copper. It is preferable that the lead wire is coated with an insulating coating material such as a Teflon type resin.
摘要:
An air-fuel ratio sensor of a limit current type is used for an air-fuel ratio feedback control. When the air-fuel ratio sensor is in a semi-activated state, the air-fuel ratio sensor is driven into an electromotive force generating mode by a current externally applied thereto thereby to shift an electromotive force changing point so that an air-fuel ratio at which the electromotive force changes stepwisely is shifted from the stoichiometric ratio point to a lean zone. When the air-fuel ratio sensor is in a completely activated state, the air-fuel ratio sensor is applied with a voltage to produce a limit current varying with an air-fuel ratio so that a feedback control is performed based on the advanced control theory by using a linear current output characteristics.
摘要:
An oxygen concentration sensor having excellent sealing performance between a lead wire and a lead wire insertion hole includes a sensor element disposed insertedly into a housing, protective covers disposed at an end portion of the housing, lead wires inserted into the protective covers, and an elastic insulating member disposed inside the protective covers and having a lead wire insertion hole for inserting the lead wires. The lead wire insertion hole in the elastic insulating member has a rib protruding in the radial direction. The elastic insulating member is caulked and fixed by the protective covers.