Abstract: An air-fuel ratio sensor deterioration-detecting device for an internal combustion engine having a catalytic converter arranged in the exhaust system, and first and second air-fuel ratio sensors arranged upstream and downstream of the catalytic converter respectively has an ECU which calculates an air-fuel ratio correction amount, based on outputs from the first air-fuel ratio sensors, and detects deterioration of the first air-fuel ratio sensor, based on the output from the first air-fuel ratio sensor. The ECU inhibits detection of deterioration of the first air-fuel ratio sensor when the air-fuel ratio correction amount falls outside a predetermined range.

Abstract: An evaporative fuel-processing system for an internal combustion engine, in which a first control valve is arranged across an evaporative fuel-guiding passage extending from a fuel tank to a canister, a second control valve across a purging passage extending from the canister to the intake system of the engine, and a third control valve at an air inlet port of the canister, respectively. An ECU generates operation command signals to the first to third control valves for closing or opening the same. The ECU is responsive to an output from a tank internal pressure sensor which detects pressure within the fuel tank and the operation command signals, for detecting an abnormality in operation of a predetermined one of the first to third control valves.

Abstract: A catalyst deterioration-determining system determines deterioration of a catalyst arranged in the exhaust passage of an internal combustion engine. An ECU is responsive to an output from an O.sub.2 sensor arranged upstream of the catalyst or outputs from O.sub.2 sensors arranged upstream and downstream of the catalyst for controlling the air-fuel ratio of a mixture supplied to the engine by means of an air-fuel ratio correction value (first air-fuel ratio control). When the engine is in a predetermined operating condition, the system effects changeover from the first air-fuel ratio control to a second air-fuel ratio control which is responsive to the output from the downstream O.sub.2 sensor for controlling the air-fuel ratio of the mixture by means of the air-fuel ratio correction value.

Abstract: A system for detecting deterioration of at least one HC sensor arranged in the exhaust passage of an internal combustion engine. There is calculated a difference between an actual value of output from the HC sensor and a predetermined reference value set in accordance with at least one parameter indicative of operating conditions of the engine, while the engine is in a predetermined operating condition. The difference is compared with a predetermined value. It is judged that there is deterioration in the HC sensor when the difference exceeds the predetermined value. In another aspect of the invention, the actual value of output from the HC sensor is corrected by a value of output from the HC sensor detected and stored when the fuel supply to the engine is cut off. Then, there is calculated a difference between the corrected actual value and the predetermined reference value.

Abstract: A system which monitors the performance of at least one HC sensor arranged in an exhaust passage of and internal combustion engine. According to a first aspect of the invention, a value of output from the at least one HC sensor is stored, which is assumed when the fuel supply to the engine is cut off, and a value of output from the at least one HC sensor is corrected by the stored value. According to a second aspect of the invention, the value of output from the at least one HC sensor assumed when the fuel supply to the engine is cut off is compared with a predetermined value, and if the former exceeds the latter, it is judged that there is abnormality in the at least one HC sensor.

Abstract: A system for detecting deterioration of a three-way catalyst of an internal combustion engine comprises first and second HC sensors, and a central processing unit (CPU). The first and second HC sensors are arranged in the exhaust passage of the engine at locations upstream and downstream of the three-way catalyst, respectively, for detecting concentration of hydrocarbons present in exhaust gases. The central processing unit (CPU) is operable to compare an output from the first HC sensor with an output from the second HC sensor, and determine from results of the comparison whether the three-way catalyst is deteriorated.

Abstract: A sheet speaker comprised of a planar piezoelectric ceramic sheet encapsulated in a planar sheet of hard resin foam, comprised of a polystyrene, urethane, urea or phenolic. The planar piezoelectric ceramic sheet is centered in the planar hard resin from sheet which provides a surface area of 10-50 times the surface area of the planar piezoelectric sheet. The surface of the planar hard resin foam may be lined with cloth, paper, or plastic film.

Abstract: An improvement in the arrangement of pad clips provided between a support and friction pads of a disc brake. Each pad clip is interposed in between guide grooves of the support and protruding parts of each friction pad in such a way as to provide anti-rattling forces with a less number of parts than the conventional arrangement; to provide a guiding face for the friction pad; and to facilitate assembly work.

Abstract: An improvement over the caliper carrying structure of a pin-slide type disc brake. A caliper straddling a disc is arranged to be slidable in the axial direction of the disc through a pair of slide pins. At least one of the slide pins is secured either to the caliper or to a fixed support disposed at the periphery of the disc and is arranged to be in slidable engagement through a rigid sleeve with an opening formed either in the support or in the caliper. The rigid sleeve is prevented from pulling off its position by a flange formed at one end thereof and is kept between the support and the caliper. The outer and inner circumferential faces of the rigid sleeve are slidable both on the opening and on the slide pin. With two sliding parts provided in this manner, each sliding part is provided with a sealing device independently of the other for protection from the outside.