An electrochemical reactor 70 is provided with a proton conductive solid electrolyte layer 75; an anode layer 76 arranged on the surface of the solid electrolyte layer and able to hold water molecules; a cathode layer 77 arranged on the surface of the solid electrolyte layer; and a current control device 73 controlling a current flowing through the anode layer and the cathode layer. The current control device reduces the current flowing through the anode layer and the cathode layer, when the water molecules held in the anode layer become smaller in amount.

Provided is an exhaust gas purification catalyst of OSC material-containing type that allows a favorable HC purification (oxidation) treatment to be performed even in a case where HC emissions are comparatively large, such as during engine startup. The exhaust gas purification catalyst of the present invention includes, as a catalyst layer (20), a front section (24) positioned upstream in an exhaust gas flow direction, and a rear section (26) positioned downstream of the front section in the exhaust gas flow direction. The front section contains Pd as a catalyst metal but does not contain an OSC material. The proportion, at which the front section is formed from the upstream leading end in the exhaust gas flow direction, is 10% to 40% with respect to 100% of a total length of the substrate (1) in the exhaust gas flow direction.

An exhaust aftertreatment system includes a first stage catalytic converter, a second stage catalytic converter, and a conduit extending from the first stage catalytic converter to the second stage catalytic converter. The conduit passes through an exhaust gas intercooler, between the first and second stage catalytic converts, that reduces the temperature of the exhaust to about 300 F. to about 500 F. Air is ejected into the exhaust conduit to increase the oxygen concentration in the exhaust before it passes through the second stage catalytic converter. The air can be ejected from an air ejection conduit that extends to an engine charger compressor or a compressed air conduit that extends from the engine charger compressor, such as a turbo charger and/or a supercharger, to the engine. A gas particulate filter can be disposed in the exhaust conduit or it can be integrated with the second stage catalytic converter, for example as a catalyzed gas particulate filter.

When stopping combustion in a cylinder under a situation in which the crankshaft of an internal combustion engine having an ignition device is rotating, a controller executes a fuel introduction process of injecting fuel from a fuel injection valve and introducing the fuel from inside the cylinder to the exhaust passage without burning the fuel. Also, the controller executes a storing process before starting the fuel introduction process. In the storing process, the controller stores oxygen in a three-way catalyst by executing a fuel cutoff process of stopping fuel injection of the fuel injection valve under a situation in which the crankshaft is rotating.

An after treatment method for a lean-burn engine is disclosed. The after treatment method is configured to control an after treatment system sequentially equipped with an ammonia production catalyst module, a selective catalytic reduction (SCR) catalyst, and a CO clean-up catalyst (CUC) on an exhaust pipe through which an exhaust gas flows and which is connected to a lean-burn engine. NH.sub.3 generation in the ammonia production catalyst module is changed according to a temperature and a temperature change rate of the SCR catalyst.

An after treatment system for a lean-burn engine is disclosed. The after treatment system is sequentially equipped with an ammonia production catalyst module, a selective catalytic reduction (SCR) catalyst, and a CO clean-up catalyst (CUC) on an exhaust pipe through which an exhaust gas flows and which is connected to a lean-burn engine. An exhaust flow changer is disposed between the ammonia production catalyst module and the SCR catalyst. The exhaust flow changer changes flow of an exhaust gas discharged from the ammonia production catalyst module according to a temperature of the SCR catalyst.

An internal combustion engine 1 is provided, in an exhaust passage thereof with an electrochemical reactor including: an ion conductive solid electrolyte layer; an anode layer arranged on a surface of the solid electrolyte layer; and a cathode layer arranged on a surface of the solid electrolyte layer and able to hold NO.sub.X. The engine includes a current control device for controlling the current supplied to the electrochemical reactor so as to flow from the anode layer through the solid electrolyte layer to the cathode layer. The current control device is configured so as to supply current to the electrochemical reactor at least temporarily while that internal combustion engine is stopped.

An exhaust gas system for an internal combustion engine, comprising a first exhaust emission control device close to the engine and a second exhaust emission control device remote from the engine. The second exhaust emission control device is heatable by a combination of an upstream burner and an electric heating device. For heating the exhaust emission control devices after an engine start, the internal combustion engine is operated with at least one engine-internal measure for raising the exhaust gas temperature, and the burner and the electric heating device are activated at the same time or offset in time for heating the second exhaust emission control device. A mixed gas entering the second exhaust emission control device is set to a stoichiometric lambda value. The invention allows accelerated heating of the exhaust emission control devices, and thus, a reduction in starting emissions.

This invention provides a multinary solid solution fine particle represented by Pd.sub.xRu.sub.yM.sub.z (M is at least one member selected from the group consisting of Rh, Pt, Cu, Ag, Au and Ir. x+y+z=1, x+y=0.01 to 0.99, z=0.99 to 0.01, x:y=0.1:0.9 to 0.9:0.1), a method for producing the same, and a supported catalyst.

A vehicle includes an engine, a fueling system, an exhaust assembly, and a controller. The fueling system controls fuel to the engine. The exhaust assembly releases combustion gas from the engine and includes at least one sensor and a catalytic converter. The controller is configured to control the engine, the fueling system and the exhaust assembly. The controller evaluates engine state and an output from the at least one sensor and commands a fueling strategy to control an oxygen storage capacity of the catalytic converter based on the engine state and output from the at least one sensor.