Abstract: A gas sensor is equipped with a sensor device made of a stack of a solid electrolyte body, a sensor electrode, a reference electrode, a first insulator, a second insulator, a gas chamber, a reference gas duct, a heater, and a heat transfer member. The heater has a heating element at least partially overlapping the sensor electrode and the reference electrode. The heat transfer member is made of a dense metallic oxide material which blocks passage of measurement gas therethrough. The heat transfer member is held between the sensor electrode and the first insulator in which the heater is embedded within the gas chamber and works to facilitate transfer of thermal energy, as generated by the heater, to the solid electrolyte body, the sensor electrode, and the reference electrode. This results in enhanced thermal conductivity of the sensor device and achieves quick activation of the sensor device.

Abstract: The present invention provides, as one aspect, a gas sensor element including a solid electrolytic substance having a bottomed cylindrical shape and oxygen ion conductivity, a reference electrode arranged on an inner side surface of the solid electrolytic substance, a measuring electrode arranged on an outer side surface of the solid electrolytic substance, and a protective layer which covers the outer side surface of the solid electrolytic substance together with the measuring electrode and which allows gas to be measured to pass through the protective layer, wherein an end side of the gas sensor element is formed of a leg portion whose profile line is straight on an axial cross section and a bottom portion whose profile line is curved, and the film thickness of the protective layer of the bottom portion is larger than the film thickness of the protective layer of the leg portion.

Abstract: A gas sensor element with a bottom part is composed of at least a solid electrolyte body of oxygen ion conductivity, a reference electrode, a detection electrode, an electrode protection layer which supports noble metal catalyst, and a heater. The electrode protection layer is composed of a covering layer, a catalyst layer and a poisoning layer. A quantity of the noble metal catalyst supported in the electrode protection layer at the bottom part of the gas sensor element is larger than that in the electrode protection layer at a leg part of the gas sensor. The bottom part of the gas sensor element has a high temperature rising speed more than the leg part when the heater generates heat energy.

Abstract: A gas sensor element includes a solid electrolyte body having oxygen ion conductivity and electrode layers formed on both surfaces of the solid electrolyte body configuring a pair of electrodes. The gas sensor element detects concentration of a selected component included in a measured gas. In the gas sensor element, closed pores having an average pore diameter of 5 nm or more and 120 nm or less are dispersed in the electrode layers, porosity measured by cross-sectional observation of the electrode layers is 1% or more and 18% or less, and 90% or more of the closed pores is dispersed within metal grains forming the electrode layers.

Abstract: A gas sensor element with a bottom part is composed of at least a solid electrolyte body of oxygen ion conductivity, a reference electrode, a detection electrode, an electrode protection layer which supports noble metal catalyst, and a heater. The electrode protection layer is composed of a covering layer, a catalyst layer and a poisoning layer. A quantity of the noble metal catalyst supported in the electrode protection layer at the bottom part of the gas sensor element is larger than that in the electrode protection layer at a leg part of the gas sensor. The bottom part of the gas sensor element has a high temperature rising speed more than the leg part when the heater generates heat energy.

Abstract: The present invention provides, as one aspect, a gas sensor element including a solid electrolytic substance having a bottomed cylindrical shape and oxygen ion conductivity, a reference electrode arranged on an inner side surface of the solid electrolytic substance, a measuring electrode arranged on an outer side surface of the solid electrolytic substance, and a protective layer which covers the outer side surface of the solid electrolytic substance together with the measuring electrode and which allows gas to be measured to pass through the protective layer, wherein an end side of the gas sensor element is formed of a leg portion whose profile line is straight on an axial cross section and a bottom portion whose profile line is curved, and the film thickness of the protective layer of the bottom portion is larger than the film thickness of the protective layer of the leg portion.

Abstract: In an oxygen sensor for installation in the exhaust gas system of a vehicle for detecting a concentration of NOx in exhaust gas downstream from a catalytic converter, in which the exhaust gas is passed through a protective layer to an electrode disposed at one side of a solid electrolyte in a sensor element of the oxygen sensor, the protective layer is formed with a combination of values of thickness and porosity which provide improved sensitivity in detecting low levels of NOx in the exhaust gas.

Abstract: A fuel injection valve for an engine includes a nozzle located in the vicinity of a cylinder head of the engine. The nozzle has nozzle holes each being opposed to an in-cylinder space defined in a cylinder of the engine. Each nozzle hole has an imaginary injection line that extends from each nozzle hole into the in-cylinder space. The imaginary injection line is directed toward either an upper surface of the piston or the wall surface of the cylinder. The in-cylinder space includes divided spaces each including the nozzle and at least one imaginary injection line. The divided spaces include a piston-side divided space and a head-side divided space. The head-side divided space contains fuel and air mixed at an air fuel ratio that is greater than an air fuel ratio of fuel and air in the piston-side divided space.

Abstract: A fuel injection valve for an engine includes a nozzle located in the vicinity of a cylinder head of the engine. The nozzle has nozzle holes each being opposed to an in-cylinder space defined in a cylinder of the engine. Each nozzle hole has an imaginary injection line that extends from each nozzle hole into the in-cylinder space. The imaginary injection line is directed toward either an upper surface of the piston or the wall surface of the cylinder. The in-cylinder space includes divided spaces each including the nozzle and at least one imaginary injection line. The divided spaces include a piston-side divided space and a head-side divided space. The head-side divided space contains fuel and air mixed at an air fuel ratio that is greater than an air fuel ratio of fuel and air in the piston-side divided space.