In an internal combustion engine of the present invention, an exhaust purification catalyst (13) and a hydrocarbon supply valve (15) are disposed in an engine exhaust path, and NO.sub.x contained in exhaust gas is purified by injecting hydrocarbon from the hydrocarbon supply valve (15) at a predetermined cycle. With respect to the injection amount per unit time of the hydrocarbon from the hydrocarbon supply valve (15), there is a difference provided between the first half and the second half of one injection time period, and in the first-half injection time period (Y), the injection amount per unit time of hydrocarbon is made to be less as compared to the second-half injection time period (X).

An emissions treatment system for an exhaust stream of an internal combustion engine including hydrocarbons, carbon monoxide, and nitrogen oxides is provided. The disclosed system can include an exhaust conduit in fluid communication with the internal combustion engine via an exhaust manifold; a first three-way conversion catalyst (TWC-1) located downstream of the internal combustion engine in the exhaust conduit; an SCR-HCT catalyst comprising a selective catalytic reduction catalyst and a hydrocarbon trap downstream of the TWC-1 in the exhaust conduit; and a third catalyst downstream of the SCR-HCT combination in the exhaust conduit, the third catalyst comprising a platinum group metal (PGM) e.g., in an amount effective to oxidize hydrocarbons. Methods of making and using such systems and components thereof are also provided.

A heater includes: a plate-like first heater substrate; an electrical heating wire that is provided on a first surface of the first heater substrate in a parallel circuit; electrodes that are connected to the electrical heating wire to allow current to flow in the electrical heating wire; and a plate-like cover substrate that covers the first surface of the first heater substrate, the electrical heating wire, and the electrodes with a second surface thereof. The electrical heating wire of the heater generates heat, so that the amount of heat is supplied. A honeycomb structure includes at least one heater that is provided so as to surround an outer wall thereof.

A process for the removal of nitrous oxide from a gas stream having a contaminating concentration of nitrous oxide to provide a gas stream with a significantly reduced concentration of nitrous oxide is described. The process includes the use of a process system having multiple N.sub.2O decomposition reactors each of which contain a nitrous oxide decomposition catalyst and heat transfer units each of which contain a heat sink media that are operatively connected in a particular order and arrangement for use in the process. The gas stream is passed to the process system that is operated for a period of time in a specific operating mode followed by the stopping of such operation and reversal of the process flow. These steps may be repeatedly taken in order to provide for an enhanced energy recovery efficiency for a given nitrous oxide destruction removal efficiency.

A process for the removal of nitrous oxide from a gas stream having a contaminating concentration of nitrous oxide to provide a gas stream with a significantly reduced concentration of nitrous oxide is described. The process includes the use of a process system having multiple N.sub.2O decomposition reactors each of which contain a nitrous oxide decomposition catalyst and heat transfer units each of which contain a heat sink media that are operatively connected in a particular order and arrangement for use in the process. The gas stream is passed to the process system that is operated for a period of time in a specific operating mode followed by the stopping of such operation and reversal of the process flow. These steps may be repeatedly taken in order to provide for an enhanced energy recovery efficiency for a given nitrous oxide destruction removal efficiency.

A layered catalyst composite for the treatment of exhaust gas emissions, effective to provide lean NO.sub.x trap functionality and three-way conversion functionality is described. Layered catalyst composites can comprise catalytic material on a substrate, the catalytic material comprising at least two layers. The first layer comprising rare earth oxide-high surface area refractory metal oxide particles, an alkaline earth metal supported on the rare earth oxide-high surface area refractory metal oxide particles, and at least one first platinum group metal component supported on the rare earth oxide-high surface area refractory metal oxide particles. The second layer comprising a second platinum group metal component supported on a first oxygen storage component (OSC) and/or a first refractory metal oxide support and, optionally, a third platinum group metal supported on a second refractory metal oxide support or a second oxygen storage component.

A reducing agent injection device includes a honeycomb structure having a honeycomb structure body and a pair of electrode members arranged in a side surface of the honeycomb structure body and a urea spraying device spraying a urea water solution in mist form. The urea water solution sprayed from the urea spraying device is supplied inside cells from a first end face of the honeycomb structure body, and urea in the urea water solution supplied in the cells is heated and hydrolyzed inside the electrically heated honeycomb structure body to generate ammonia. The ammonia is discharged outside the honeycomb structure body from a second end face and injected outside. There is provided a reducing agent injection device that can generate and inject ammonia from a urea solution with less energy.

An exhaust gas-purifying catalyst material includes first oxide particles having an average particle diameter D.sub.av of 1 μm to 95 μm and having an oxygen storage capacity, second oxide particles having an average particle diameter D.sub.av of 0.05 μm to 0.5 μm, containing a metal element, and having no oxygen storage capacity, precious metal particles, and acidic oxide particles. The material has a correlation coefficient ρ of 0.45 or more obtained using first characteristic X-ray intensity for the metal element contained in the second oxide particle, second characteristic X-ray intensity for an element other than oxygen contained in the acidic oxide particle, and third characteristic X-ray intensity for a precious metal element contained in the precious metal particle.

Uses are disclosed for a new crystalline molecular sieve designated SSZ-102 synthesized using an N,N′-dimethyl-1,4-diazabicyclo[2.2.2]octane dication as a structure directing agent. SSZ-102 has ESV framework topology.

To reduce an OSC material, while maintaining necessary OSC capacity; and to improve heat resistance and reactivity of a precious metal. Proposed is an exhaust gas purifying catalyst which comprises a first catalyst layer that is formed on the surface of a substrate that is formed of a ceramic or a metal, and a second catalyst layer that is formed on the upper side of the first catalyst layer. The first catalyst layer comprises a precious metal, an OSC material and an alumina, and the OSC material and the alumina are comprised at a mass ratio of OSC material:alumina=1:7 to 1:3. The second catalyst layer comprises a precious metal, an OSC material and an alumina, and the OSC material and the alumina are comprised at a mass ratio of OSC material:alumina=1:1 to 10:0.