Abstract: A honeycomb-shaped substrate for catalyst is made from ceramic, has a straight-flow structure, and includes cellular walls exhibiting pore volumes, which differ partially, and a large number of cellular passages demarcated by the cellular walls. A catalyst for purifying exhaust gases is produced by providing the cellular walls of the honeycomb-shaped substrate with a catalytic coating layer.

Abstract: A hexagonal cell honeycomb structure body has a plurality of hexagonal cells. Each hexagonal cell is surrounded by six cell walls in a hexagonal lattice shape. A R-shaped corner part of an approximate circular-arc shape is alternately formed at interior angle parts of the six cell walls forming each hexagonal cell. The three R-shaped corner parts are at the alternate internal corners of each hexagonal cell observed from a cross section of the axis direction of the hexagonal cell honeycomb structure body. A radius of curvature of each R-shaped corner part is larger than that of the interior corner part having no R-shaped corner part. The minimum radius of curvature of the R-shaped corner part is 2.8 to 5 times of a thickness of each hexagonal cell wall, namely within a range of 0.25 mm to 0.45 mm.

Abstract: A honeycomb structure body is composed of hexagonal cells and an outer peripheral wall. Each hexagonal cell is surrounded by six cell walls of a hexagonal arrangement. The cell walls are divided into standard cell walls and reinforced cell walls. The strength of each reinforced cell wall is stronger than that of each standard cell wall. The reinforced cell walls form a strength reinforced area. Each component in the strength reinforced area has an approximate straight-line shape observed on a cross section in the diameter direction of the honeycomb structure body. Both ends of each component in the strength reinforced area are contacted to the outer peripheral wall.

Abstract: A honeycomb-shaped substrate for catalyst is made from ceramic, has a straight-flow structure, and includes cellular walls exhibiting pore volumes, which differ partially, and a large number of cellular passages demarcated by the cellular walls. A catalyst for purifying exhaust gases is produced by providing the cellular walls of the honeycomb-shaped substrate with a catalytic coating layer.

Abstract: A hexagonal cell honeycomb structure body has a plurality of hexagonal cells. Each hexagonal cell is surrounded by six cell walls in a hexagonal lattice shape. A R-shaped corner part of an approximate circular-arc shape is alternately formed at interior angle parts of the six cell walls forming each hexagonal cell. The three R-shaped corner parts are at the alternate internal corners of each hexagonal cell observed from a cross section of the axis direction of the hexagonal cell honeycomb structure body. A radius of curvature of each R-shaped corner part is larger than that of the interior corner part having no R-shaped corner part. The minimum radius of curvature of the R-shaped corner part is 2.8 to 5 times of a thickness of each hexagonal cell wall, namely within a range of 0.25 mm to 0.45 mm.

Abstract: There is provided a desulphurization apparatus to be mounted in automobiles, which is arranged between a fuel tank and an injector of an engine, the apparatus comprising a combination of a sulfur-containing compound adsorbent for adsorbing and concentrating the sulfur-containing compound and a sulfur-containing compound oxidizing agent or oxidation catalyst for oxidizing the adsorbed sulfur-containing compound, the apparatus further comprising a means for recovering and removing the resulting sulfur-containing oxide. According to this apparatus, the quantity of the particulate matter in an exhaust gas is reduced by half and the durability of the catalyst for removing a nitrogen oxide is improved by a factor of about two.

Abstract: The present invention is a method of solidifying sulfur component being the cause of “SOx poisoning” by use of a sulfur solidifier. The solidifier includes a metal element having a function of oxidizing the sulfur component and a basic metal element. And the solidifier solidifies sulfur component before exhaust gas flows into an NOx-occluding reduction-type exhaust purifying catalyst located on an exhaust path. Since the foregoing sulfur solidifier includes the above metal element and the basic metal element, it can effectively solidify the sulfur component which are the cause of the SOx poisoning, and ensure improvement in purification performance.

Abstract: There is provided a desulphurization apparatus to be mounted in automobiles, which is arranged between a fuel tank and an injector of an engine, the apparatus comprising a combination of a sulfur-containing compound adsorbent for adsorbing and concentrating the sulfur-containing compound and a sulfur-containing compound oxidizing agent or oxidation catalyst for oxidizing the adsorbed sulfur-containing compound, the apparatus further comprising a means for recovering and removing the resulting sulfur-containing oxide. According to this apparatus, the quantity of the particulate matter in an exhaust gas is reduced by half and the durability of the catalyst for removing a nitrogen oxide is improved by a factor of about two.

Abstract: The present invention is a method of solidifying sulfur component being the cause of “SOx poisoning” by use of a sulfur solidifier. The solidifier includes a metal element having a function of oxidizing the sulfur component and a basic metal element. And the solidifier solidifies sulfur component before exhaust gas flows into an NOx-occluding reduction-type exhaust purifying catalyst located on an exhaust path. Since the foregoing sulfur solidifier includes the above metal element and the basic metal element, it can effectively solidify the sulfur component which are the cause of the SOx poisoning, and ensure improvement in purification performance.

Abstract: According to the present invention, there is provided an exhaust gas purification device for an engine having an exhaust passage, the device comprising a catalyst arranged in the exhaust passage and having an upstream end and a downstream end, a purification ratio of exhaust gas by the catalyst becoming more than a predetermined ratio when a temperature of the catalyst is within a predetermined temperature range, cooling means for cooling the upstream end of the catalyst, heating means for heating the downstream end of the catalyst, and control means for controlling the cooling means and the heating means to maintain the temperature of a portion of the catalyst, which portion is positioned between the upstream end and the downstream end, in the predetermined temperature range.

Abstract: According to the present invention, there is provided an exhaust gas purification device for an engine having an exhaust passage, the device comprising a catalyst arranged in the exhaust passage and having an upstream end and a downstream end, a purification ratio of exhaust gas by the catalyst becoming more than a predetermined ratio when a temperature of the catalyst is within a predetermined temperature range, cooling means for cooling the upstream end of the catalyst, heating means for heating the downstream end of the catalyst, and control means for controlling the cooling means and the heating means to maintain the temperature of a portion of the catalyst, which portion is positioned between the upstream end and the downstream end, in the predetermined temperature range.

Abstract: In a fuel injection control system, a throttle valve is provided on the intake air passage of a diesel engine and an EGR control valve is provided for recycling a part of the engine exhaust gas to the intake air system of the engine. An engine control unit (ECU) controls the intake air amount of the engine to a value corresponding to the engine operating condition by adjusting the throttle valve and the EGR control valve. Further, the ECU detects the actual intake air amount by an airflow meter disposed at the inlet of the intake air passage and determines the maximum fuel injection amount based on the engine speed and the actual intake air amount. The maximum fuel injection amount is the maximum amount of the fuel which does not generate the exhaust smoke.

Abstract: According to the invention, there is provided an exhaust gas purification device for purifying an exhaust gas discharged from an engine having cylinders including first and second cylinders. An exhaust stroke in the first cylinder is carried out next to an exhaust stroke in the second cylinder. The exhaust gas purification device comprises exhaust branch passages which are connected to the cylinders, respectively. The exhaust branch passages include first and second exhaust branch passages which are connected to the first and second cylinders, respectively. The exhaust gas purification device comprises a common exhaust passage connected to the exhaust branch passages, a catalyst positioned in the common exhaust passage for purifying an exhaust gas, and an exhaust gas recirculation passage connected to the first exhaust branch passage. The exhaust gas recirculation passage introduces the exhaust gas from the first exhaust branch passage into an intake passage which is connected to the cylinders.

Abstract: According to the present invention, there is provided a fuel injecting device for injecting fuel into a cylinder of an engine. A fuel injector injects a main fuel charge into the cylinder at a predetermined first timing, and the fuel injector injects additional fuel into the cylinder at a predetermined second timing which is different from the predetermined first timing. It is judged if an amount of fuel adhering to an inner wall of the cylinder is larger than a predetermined fuel amount when the fuel injector injects the additional fuel. The fuel injector inject the additional fuel such that an amount of fuel adhering to the inner wall of the cylinder becomes smaller than the predetermined fuel amount when it is judged that an amount of fuel adhering to the inner wall of the cylinder is larger than the predetermined fuel amount.

Abstract: An exhaust gas purification device, for an engine having an exhaust passage, said device comprising a catalyst arranged in the exhaust passage for purifying NO.sub.x with a reducing agent. A purification ratio of the NO.sub.x by said catalyst becomes more than a predetermined ratio when a temperature of said catalyst is within a predetermined temperature range. A predetermined amount of a reducing agent is fed to said catalyst. An amount of the reducing agent to be fed is increased with respect to the predetermined amount when a temperature of an upstream end of the catalyst is lower than a lowest value of the predetermined temperature range and a temperature of a downstream end of the catalyst is higher than the lowest value.

Abstract: An exhaust gas purifying device for an engine comprises an exhaust gas purifying catalyst arranged in the exhaust passage. The catalyst is capable of reducing NO.sub.X in the catalyst in the oxidizing atmosphere, and comprises a reducing agent adsorbent adsorbing a reducing agent in the inflowing exhaust gas therein when the pressure in the adsorbent becomes higher, and desorbing the adsorbed reducing agent therefrom when the pressure in the adsorbent becomes lower. An exhaust gas control valve is disposed in the exhaust passage downstream of the catalyst. When both the engine load and the engine speed are low, the opening of the valve is made smaller to increase the pressure in the catalyst. At this time, hydrocarbon is fed to the catalyst, and is then adsorbed in the catalyst. When the engine load or the engine speed becomes high, or the cumulative amount of hydrocarbon fed to the catalyst becomes larger than a predetermined amount, the valve is made fully open to reduce the pressure in the catalyst.

Abstract: An exhaust gas purifying device, for an engine performing a lean operation and having an EGR system capable of controlling an EGR ratio, comprises a NO.sub.X catalyst arranged in the exhaust passage capable of selectively reducing NO.sub.X in the inflowing exhaust gas, in the oxidizing atmosphere including a reducing agent, and a reducing agent injector arranged in the exhaust passage of the engine for secondarily supplying a reducing agent to the exhaust passage upstream of the NO.sub.X catalyst. The EGR system has an EGR passage connecting the exhaust passage and the intake passage of the engine, an EGR control valve arranged in the EGR passage, and an intake air control valve arranged in the intake passage upstream of an inlet of the EGR passage. The openings of the EGR control valve and the intake air control valve are controlled to control the temperature of the exhaust gas to make the temperature of the NO.sub.X catalyst within the optimum temperature range or equal to the optimum temperature.

Abstract: According to the present invention, SO.sub.X in the exhaust gas of an internal combustion engine is absorbed by a sulfate absorbent which absorbs SO.sub.X in the exhaust gas when the temperature is lower than a releasing temperature and releases the absorbed SO.sub.X when the temperature becomes higher than the releasing temperature. When the exhaust gas temperature increases during the operation of the engine and reaches the releasing temperature, the temperature of the exhaust gas flowing into the sulfate absorbent is further raised to a predetermined temperature by supplying fuel to the exhaust gas passage upstream of the sulfate absorbent. The ratio of SO.sub.3 in the SO.sub.X mixture released from the sulfate absorbent changes in accordance with the temperature, and takes the highest value at a certain temperature (i.e., a peak temperature). Therefore, when the exhaust gas temperature is raised above the peak temperature, the ratio of SO.sub.3 in the SO.sub.

Abstract: A fuel injection control device for a direct injection type engine having an exhaust passage and a NO.sub.x catalyst arranged therein to purify NO.sub.x in exhaust gas discharged from the engine comprises fuel injectors for injecting fuel into a cylinder. The injecting operation of the fuel injectors is controlled to carry out a main fuel injection at the latest at the beginning of a power stroke of the engine. The injecting operation of the fuel injectors is controlled to carry out a sub fuel injection at one of a power stroke and an exhaust stroke of the engine after the main fuel injection is completed to increase an amount of hydrocarbon in the exhaust gas. The injecting operation of the fuel injectors is controlled to carry out an additional sub fuel injection after the main fuel injection is completed and before the sub fuel injection is carried out.

Abstract: A catalyst for purifying an exhaust gas comprising a zeolite catalyst ion exchanged with cobalt and at least one alkaline earth metal and a zeolite catalyst ion-exchanged with copper, provided on an inlet side of an exhaust gas stream and an outlet side of the exhaust gas respectively, or randomly present in a mixed state.