Abstract: A method for purifying an oxygen excess exhaust gas by catalytically reducing nitrogen oxides contained in the exhaust gas, which comprises bringing a catalyst comprising at least one noble metal supported on a carrier composed mainly of an oxide or a complex oxide of at least one metal selected from rare earth metals and metals of the group IV A of the periodic table of elements into contact the exhaust gas.

Abstract: A noble metal base catalyst for decomposing a portion of NOx included in engine exhaust gas into intermediate products such as N.sub.2 O and NO.sub.2 is installed in an exhaust conduit of a lean burn engine. Further, an intermediate product decomposing means for decomposing the intermediate products produced by the noble metal base catalyst into N.sub.2 and O.sub.2 is installed downstream of the noble metal base catalyst. The noble metal base catalyst has a high thermal durability, and the noble metal base catalyst and the intermediate product decomposing means decompose NOx into N.sub.2 and O.sub.2 without a large amount of HC.

Abstract: A catalyst for purifying an exhaust gas comprising a zeolite catalyst ion-exchanged with a transition metal, which is heat-treated in a gas stream containing a sulfur oxide, optionally followed by washing with a glycol.

Abstract: An internal combustion engine comprising three intake valves. The first intake valve and the second intake valve open at a crank angle near to the top dead center of the intake stroke. The third intake valve opens approximately at the center of the intake stroke. An air control valve is arranged in the second intake passage connected to the combustion chamber via the second intake valve. The air control valve is closed when the engine is operating under a partial load. A fuel injector is arranged in the third intake passage connected to the combustion chamber via the third intake valve. The injecting operation of the fuel injector is stopped during the intake stroke.

Abstract: An air intake device comprising a main air intake passage and an auxiliary air intake passage. The main air intake passage interconnects the air cleaner to the engine cylinders. The auxiliary air intake passage is connected to the air cleaner at one end thereof and to the main air intake passage at the other end thereof. The equivalent pipe lengths of the main air intake passage and the auxiliary air intake passage are almost the same. A control valve actuated in response to the engine speed is arranged in the other end of the auxiliary air intake passage. The valve body of the control valve has a conically-shaped convex front face and a conically-shaped convex rear face.

Abstract: An air intake device comprising a main air intake passage and an auxiliary air intake passage, in which the main air intake passage interconnects the air cleaner to the engine cylinders and the auxiliary air intake passage is connected to the air cleaner at one end thereof and to the main air intake passage at the other end thereof. The equivalent pipe lengths of the main air intake passage and the auxiliary air intake passage are almost the same. An air pulsation control valve actuated in response to the engine load and the engine speed is arranged in the other end of the auxiliary air intake passage. The engine has a helically-shaped intake port comprising a helical portion, an inlet passage portion, and a bypass passage branched off from the inlet passage portion and connected to the helix terminating portion of the helical portion. A flow path control valve actuated in response to the engine load is arranged in the bypass passage.

Abstract: An exhaust particle cleaning device for a diesel engine includes a trap case provided in a passage way of exhaust gas. A filter material is disposed in the trap case so that carbon particles or other exhaust particles contained in the exhaust gas can be caught within the filter material during the time the exhaust gas is passed through the filter material. A plurality of electric heater elements are spread or dispersed on the upstream end face of the filter material, so that the exhaust gas passes through the areas defined between the plurality of heater elements. The electric heater element may be coated with a ceramic material.

Abstract: An exhaust particulate cleaning device for a diesel engine comprising a trap case which is located in a passageway of the exhaust gas and which has therein a filter material for trapping the exhaust particulates contained in the exhaust gas, an electric heater for igniting and burning the exhaust particulates trapped in the filter material, a larger bypass passage of the exhaust gas bypassing the trap case, and a control valve in the bypass passage for opening and closing the bypass passage.

Abstract: An exhaust gas cleaning device comprises at least one exhaust gas flowing passage, at least one particulates collecting member composed of two filter elements having different heat capacity, which is disposed within the exhaust gas flowing passage and heating means which is interposed between the filter elements so as to be closely contacted therewith. The filter element having smaller heat capacity is disposed on the upper stream side of the heating means and the filter element having larger heat capacity is disposed on the downstream side thereof. The filter element having smaller heat capacity is rapidly heated by the heating means and the heat of the filter element having smaller heat capacity is transmitted to the filter element having larger heat capacity. All of the particulates collected by the particulates collecting member can be burnt off with excellent heat efficiency.

Abstract: This invention provides improvements in method of and apparatus for reducing an emitted amount of particulates by collecting the particulates contained in the exhaust gas from a diesel engine by a trapper. According to the invention, firstly, an excess amount of the particulates which have adhered to the trapper is detected, and thereafter, temperature of the trapper being within a range of self-burning temperature of the particulates is detected. When necessity for regenerating the trapper is ascertained based on the both detections described above, the inlet side of the trapper is heated to a range of igniting temperature of the particulates, whereby a large igniting energy required for propagating combustion is accumulated. Thereafter, secondary air is supplied to the trapper to ignite the particulates, and combustion is propagated to the particulates being within the range of self-burning temperature thereof by the secondary air continuously supplied, to thereby regenerate the trapper.

Abstract: An exhaust gas cleaning device for an internal combustion engine comprises a housing provided with an inlet port which is communicated with an exhaust pipe of an internal combustion engine and an outlet port, two particulates collecting members disposed in two independent exhaust gas flowing passages which are communicated with the inlet port through an inlet chamber and with the outlet port through an outlet chamber, a butterfly valve provided in the inlet chamber for alternately directing the exhaust gases into either one of the exhaust gas flowing passages and a heated air supplying means for burning off the particulates collected by the particulates collecting members, which is provided with a heated air outlet port opening into the inlet chamber so as to be opposed to the inlet port with the butterfly valve therebetween.

Abstract: An exhaust gas cleaning device comprises a casing provided with an inlet port which is communicated with an exhaust pipe of an internal combustion engine and an outlet port, two particulates collecting members disposed in two independent exhaust gas flowing passages which are communicated with the inlet port and the outlet port of the casing, a valve means provided on the downstream side of the two exhaust gas flowing passages for selectively passing the exhaust gases into either one of the exhaust gas flowing passages and a heated air supplying means provided on the downstream side of the collecting members for selectively supplying heated air into either one of the particulates collecting members.

Abstract: A variable venturi type carburetor of an internal combustion engine which includes a housing, a bore extending through the housing and having an inner wall defining an intake passage, a suction piston movably mounted in the housing and having a head portion projecting into the intake passage and a fuel injection valve. The suction piston moves so as to change the cross-sectional area of the venturi portion defined between the head portion of the suction piston and an inner wall of the intake passage. A pipe member connected to the fuel injection valve is opened to the intake passage in a position opposite the head portion with regard to the intake passage. The fuel injected from the injection valve is supplied through the pipe member to the intake passage.

Abstract: A variable venturi type carburetor of an internal combustion engine which includes a housing, a bore extending through the housing and having an inner wall defining an intake passage, a suction piston movably mounted in the housing and having a head portion projecting into the intake passage and a fuel injection valve arranged at the position opposite to the head portion of the suction piston with regard to the intake passage. The suction piston moves so as to change the cross-sectional area of the venturi portion defined between the head portion of the suction piston and an inner wall of the intake passage. The head portion of the suction piston is provided with a recess which extends along a line crossing with the central axis of the suction piston and is arranged in parallel to the direction of air flowing in the intake passage.

Abstract: In an exhaust gas recirculation system for an internal combustion engine, a flow control valve is disposed within a recirculation pipe and operatively connected to a pneumatically operated servomotor to control the flow quantity of exhaust gases through the recirculation pipe, and an orifice is disposed within the recirculation pipe upstream of the valve to form a space between the valve and the orifice. A pressure regulator serves to modulate negative pressure from an engine intake manifold to the servomotor on a basis of pneumatic pressure applied thereto and pressure in the space. The pneumatic pressure applied to the pressure regulator is electrically controlled to satisfy the following equation.Pd=f(Pv, N)where the character Pd is the pneumatic pressure applied to the pressure regulator, and the characters Pv and N respectively indicate the negative pressure in the intake manifold and the engine speed.

Abstract: An apparatus for introducing secondary air into an exhaust system of an internal combustion engine, provided with a three-way catalytic converter in the exhaust system. The apparatus includes a first air flow control valve adapted for controlling the amount of air introduced into the exhaust system in accordance with the atmosphere of the exhaust gas so as to cause it to be kept near stoichiometric atmosphere, and a second air flow control valve adapted for preliminarily controlling the amount of secondary air introduced into said first air flow control valve in accordance with the amount of engine fluid passing through the intake system or exhaust system. The atmosphere control operation by the first air flow control valve is effectively promoted by the second air flow control valve, so that atmosphere of the exhaust gas can be strictly and precisely controlled to said stoichiometric atmosphere for proper operation of the three-way catalytic converter.

Abstract: Apparatus for feeding water to the air/fuel mixture passage between the air/fuel mixing device and combustion chamber of an internal combustion engine including a main conduit for supplying water to the mixture passage, a valve member for opening and closing the conduit, the valve member being biased into the closed position, a diaphragm communicating on one side directly to the mixture passage for actuating the valve member to an open position and on the other side through a pressure delay chamber with the mixture passage, wherein the conduit is opened only by a relatively abrupt increase in pressure in the mixture passage, and the closing is delayed until the pressure equalizes across the diaphragm. Water may be supplied to the conduit directly by a pump, or by a pressure differential or by means of a reservoir having access to a water supply.