Abstract: An automotive exhaust catalyst includes a support, which is less likely to adsorb SO.sub.x contained in exhaust gases thereon, an NO.sub.x storage compound loaded on the support, and a noble metal element loaded on the support. The support is an alumina support with a Ti--Zr composite oxide loaded thereon, or is formed of a Ti--Zr or Ti--Zr--Y composite oxide. The composite oxide inhibits the NO.sub.x storage compound, which is selected from alkali metals, alkaline-earth metals and rare-earth elements, from being poisoned by sulfur, and enhances the thermal resistance of the support. Thus, the automotive exhaust catalyst can effectively purify NO.sub.x contained in lean-side exhaust gases, even after it is subjected to a thermal durability test.

Abstract: An internal combustion engine in which a three-way catalyst (12) for purification of the exhaust gas is arranged in the exhaust passage, wherein the relationship between the magnitude of the stress causing deterioration of the three-way catalyst (12), for example the catalytic bed temperature, and the rate of deterioration of the performance of the catalyst is found. A durability test is performed by raising the catalytic bed temperature higher than that of the vehicle under market driving. The length of the durability test at this time is determined from the relationship between the catalytic bed temperature and the rate of deterioration of the performance of the catalyst so as to give the same degree of deterioration of the performance of the catalyst as with market driving. The length of the durability test required for giving the same degree of deterioration of the performance of the catalyst is much shorter than the market driving time.

Abstract: The method for purifying combustion exhaust gas according to the present invention utilizes a NH.sub.3 decomposing catalyst. The NH.sub.3 decomposing catalyst in the present invention is capable of converting substantially all of the NH.sub.3 in the combustion exhaust gas to N.sub.2 when the air-fuel ratio of the exhaust gas is lean and the temperature of the catalyst is within a predetermined optimum temperature range. Further, when the exhaust gas contains NO.sub.x in addition to NH.sub.3, the NH.sub.3 decomposing catalyst is capable of reducing the NO.sub.x in the optimum temperature range even though the air-fuel ratio of the exhaust gas is lean. In the present invention, the conditions of the exhaust gas containing NO.sub.x are adjusted before it is fed to the NH.sub.3 decomposing catalyst in such a manner that the temperature of the exhaust gas is within the optimum temperature range and the air-fuel ratio of the exhaust gas is lean. Further, NH.sub.

Abstract: A device for evaluating catalyst performance deterioration includes an air-fuel ratio sensor and a temperature sensor. The degree of catalyst performance deterioration per unit time is calculated based on the concentration of oxygen in the exhaust gas and the temperature of the catalyst. The deterioration of the catalyst is evaluated on the basis of the accumulated value of the degree of catalyst performance deterioration per unit time.

Abstract: A method and device of readily detecting deterioration of a sample at low cost, which do not require any maintenance and monitoring of the sensor properties, and accordingly can decrease a load assigned to a system side. A conductive sensor having a pair of electrodes and a conductive film which is disposed between the pair of electrodes and is composed of a conductive material formed in a continuous region so as to connect the pair of electrodes at least electrically in its initial state is placed in an atmosphere where the sample is placed. The percolation transition of the conductive material of the conductive film occurs due to the grain growth thereof, accompanied by the deterioration of the inorganic material composing the sample due to the grain growth thereof. By monitoring the variation in electric resistance of the conductive sensor due to the percolation transition of the conductive material, the deterioration of the sample can be detected.

Abstract: A process for purifying an exhaust gas comprising carbon monoxide, hydrocarbons, nitrogen oxides, and sulfur oxides by periodically adjusting exhaust gas conditions from lean-burn to fuel-rich and by using a catalyst comprising an alumina support with lithium dissolved therein to form a solid solution, at least one first ingredient selected from the group consisting of platinum and palladium loaded on the alumina support, and at least one second ingredient selected from the group consisting of alkali elements, alkaline-earth elements, and rare-earth elements loaded on the support. Sulfates formed from sulfur oxides in the exhaust gas are decomposed by the lithium under the fuel-rich conditions to inhibit the alumina support from being acidified.

Abstract: A process for efficiently reducing nitrogen oxides in exhaust gases including excess oxygen. The process includes intermittently introducing a reducing agent, such as hydrogen and carbon monoxide, for reducing nitrogen oxides to a reducing catalyst, such as platinum, disposed in an exhaust gas passage while maintaining an oxygen excess condition. The reducing agent is intermittently introduced in a manner to satisfy the following equation:[NO.sub.x ]<[H.sub.2 ]+[CO], wherein [H.sub.2 ], [CO] and [NO.sub.x ] are molar concentrations of hydrogen, carbon monoxide and nitrogen oxides, respectively. The reducing catalyst may include a transition metal, an alkaline metal and/or an alkaline earth metal.

Abstract: An apparatus for efficiently purifying NOx in the exhaust gas or soluble organic substance in the exhaust gas from a diesel engine. A plurality of purification units are arranged in a housing, each of which is composed of a catalytic layer for reducing NOx and a cooling core for cooling the exhaust gas admitted through the catalytic layer. The multi-staged purification units are so constructed to admit the exhaust gas to flow therethrough. The catalytic layer in the form of a porous carrier such as a honeycomb structure carries catalytic components. Upon purifying soluble organic substance in the exhaust gas from a diesel engine, the catalytic components carried on the catalytic layer serve to efficiently purify such substance, as well as inhibiting the reaction to form sulfate.

Abstract: An apparatus for decreasing nitrogen oxides in a combustion device of Stirling engine which performs continuous combustion includes a combustion chamber, means for supplying the combustion chamber with fuel and air, an exhaust passageway for discharging exhaust gas produced by combustion in the combustion chamber, a catalytic unit arranged in the exhaust passageway for purging toxic components contained in the exhaust gas discharged, and hydrogen supply means for supplying hydrogen gas to the exhaust gas which enters the catalytic unit. The hydrogen gas is supplied to the combustion exhaust gas which has entered the catalytic unit, and the combustion exhaust gas is then catalytically reduced in an environment of a comparatively low temperatures of less than 250.degree. C., whereby the nitrogen oxides in the exhaust gas are decreased.

Abstract: A method for purifying an exhaust gas containing an excess amount of oxygen, to remove nitrogen oxides, carbon monoxide and hydrocarbons therefrom, by bringing a catalyst into contact with the exhaust gas, the catalyst comprising a zeolite ion-exchanged with (a) cobalt or (b) both cobalt and at least one metal selected from the group consisting of alkaline earth metals and rare earth metals, the zeolite being selected from the group consisting of ferrierite, ZSM-5, ZSM-11, ZSM-12 and ZSM-20, and having a silica-to-alumina molar ratio of from 15 to 1,000.

Abstract: A lean NOx reduction catalyst capable of reducing NOx through reaction of H.sub.2 with NOx at low temperatures below 350.degree. C. is installed in a downstream portion of an exhaust pipe of an internal combustion engine in or near a muffler. Such an NOx reduction catalyst comprises, for example, Pt/zeolite catalyst. An H.sub.2 generator is installed so as to supply the H.sub.2 to an inlet side of the NOx reduction catalyst. The H.sub.2 generator may include a reforming catalyst for reforming methanol, LPG, or natural gas to generate H.sub.2. The generated H.sub.2 flows to the NOx reduction catalyst where it reacts with NOx to purify the exhaust gas.

Abstract: A direct current voltage is applied between an anodic portion containing an oxidizing catalyst provided on one surface of a proton conductive solid electrolyte which separates the flow path of the gas to be treated into two parts, and a cathodic portion containing a reducing catalyst provided on the other surface of the solid electrolyte, the reducing catalyst comprising at least one selected from oxides of elements of Group 5A, Group 6A, and Group 7A of the periodic table, palladium, palladium alloys, transition elements carried on alumina, cerium oxide, and La.sub.1-x Sr.sub.x Co.sub.1-y Fe.sub.y O.sub.3 (where, 0.ltoreq.x.ltoreq.1, 0.ltoreq.y.ltoreq.1), while bringing a gas containing water vapor into contact with the anodic portion and bringing a gas containing nitrogen oxides into contact with the cathodic portion.

Abstract: Hydrogen gas from a hydrogen generator which creates hydrogen gas by the electrolysis of water or water vapor is supplied at the entrance to a catalyzer provided in an exhaust line. The catalyzer performs a catalytic reaction between hydrogen gas and nitrogen oxides to achieve decomposition into nitrogen gas and water vapor in the exhaust from an internal combustion engine. The nitrogen oxides are directly reduced with said hydrogen gas in a low temperature atmosphere not higher than 350.degree. C. to achieve efficient reduction in the nitrogen oxides. The improved method and apparatus provide a catalytic system with which the nitrogen oxides in the exhaust from a lean burnt engine or a diesel engine can be effectively reduced irrespective of the concentration of oxygen gas in the exhaust without impairing the good fuel economy of those engines.

Abstract: A catalyst for reducing nitrogen oxides from an exhaust gas containing the same in an oxygen rich atmosphere comprising (i) a zeolite having a molar ratio of SiO.sub.2 /Al.sub.2 O.sub.3 of at least 10, (ii) copper, and (iii) a rare earth ion, an alkaline earth metal and/or a valence variable metal.

Abstract: Exhaust gas purifying method and apparatus for internal combustion engines in which the temperature of an exhaust gas purifying catalyst is detected and, as desired, oxygen content of exhaust gas is further detected, and in which the actual air-fuel ratio is varied toward the higher air-fuel ratio side and the lower air-fuel ratio side with respect to the theoretical air-fuel ratio, in accordance with the frequency and amplitude preset dependent on the kind of the catalyst and set based on these measured values.

Abstract: A data communication system which includes a data distributor, a communication station and a plurality of front-end-processors. These front-end-processors are connected with a computer through a common bus. The distributor distributes the data received by the station to one available front-end-processor, which preprocesses the received data, and transfers the pre-processed data to the computer through the bus. By operating the front-end-processors in parallel with respect to successively received packets of data, the processing speed of the system is increased.

Abstract: This invention provides a frequency-synthesizer type transceiver having a voltage-controlled oscillator and means for comparing the phases of mixed frequency, whereby the voltage-controlled oscillator is regulated by signals resulting from the phase comparison to generate a controlled frequency serving as the local oscillator frequency for transmitting and receiving. The frequency-synthesizer type transceiver further includes a means for selectively switching from the one carrier frequency to the other to differentiate the transmitting and receiving frequencies.