Abstract: The device comprises in a cylindrical case (3) of an exhaust manifold (2) of an engine, a catalyst body (12) in a centre position, and means (14, 15) for adsorbing nitrogen oxides contained in the exhaust gases of the engine in a peripheral disposition around the catalyst body (12). Preferably, the catalyst body is disposed in a pipe (8) constituting an end part of an exhaust line (8a) and the adsorbing means (14, 15) is disposed in an annular space provided between the exhaust pipe (8) surrounding the catalyst body (12) and the case (3) of the manifold (2). The device permits limiting the discharges of nitrogen oxides of the exhaust gases in all the phases of operation of the engine.

Abstract: Exhaust gas temperature is raised after a cold engine start so as to rapidly activate a catalyst in an exhaust line by retarding an ignition timing at which an air-fuel mixture is fired in the engine to a point after top-dead-center during a certain time interval and promoting combustion of the air-fuel mixture, thereby accelerating the catalyst to attain its effective activation temperature after the cold engine start as quickly as possibly.

Abstract: In a method and apparatus for monitoring the operating capability of a catalyzer in the exhaust duct of an internal combustion engine, the operating capability of the catalyzer is assessed on the basis of the increase in temperature produced by the exothermic conversion of the exhaust gases in the catalyzer. The increase in temperature is determined with the aid of two temperature signals, the first temperature signal being produced on the basis of a measurement downstream of the catalyzer and the second temperature signal being formed with the aid of a temperature model. The temperature model may form the temperature downstream of a completely inoperational catalyzer, a catalyzer which is still just sufficiently operational, or a catalyzer which is fully operational. The assessment of the operating capability of the catalyzer is performed on the basis of criteria which are matched to the temperature model used.

Abstract: A catalytic converter has an upstream catalyst-coated core and downstream catalyst-coated core housed in a same casing, the upstream core being provided with a heater. A bypass passage for bypassing the upstream core to the downstream core is formed between the casing and upstream core. By providing these two catalyst-coated cores and the bypass passage in the casing, the catalytic converter is rendered compact. Further, as the flowrate of exhaust gas through the upstream catalyst is reduced by the bypass passage, temperature rise of the upstream catalyst due to the heater is accelerated, and the emission amount of hydrocarbons and carbon oxides during engine warm-up is decreased.

Abstract: A method for reducing pollutant emissions from a Diesel engine, is performed during cold starting, partial load and/or idling. The Diesel engine has a downstream oxidation-type catalytic converter with freely penetrable channels and an inflow side having at least one electrically heatable portion. The electrically heatable portion is heated before and/or after starting of the Diesel engine to a temperature at which deposited soot ignites.

Abstract: According to the invention, during a phase in which the engine is cold-started, the mechanical power supplied by the engine (1) to an auxiliary (23) is reduced by comparison with that normally absorbed by the auxiliary in normal operation. When this auxiliary is an alternator, the reduction in the power supplied by the engine, and therefore the slightest pollution which accompanies it, may be obtained by reducing the excitation current (i) of the alternator, under the control of a computer (11).

Abstract: A number of embodiments of feedback control systems for two-cycle, internal combustion engine management systems. Each embodiment employs an exhaust system sensor which senses the exhaust gases by drawing exhaust gases from the exhaust of the engine. In some instances this is done directly from the cylinder and in others it is done in the exhaust system. In each embodiment, the sensor is provided in an accumulator chamber so as to provide an accurate signal of instantaneous engine running conditions. The use of the accumulator chamber insures that the combustible gases will not be diluted with fresh air charge, but will be able to purge from cycle to cycle so as to provide cycle-by-cycle information. Various arrangements are provided for protecting the sensor element including serpentine flow paths, shields, the direction in which the exhaust gases are delivered, lubricant catalysts, conduit shape, sensor cooling and combinations of these features.

Abstract: A method for utilizing a silencer unit attached to an exhaust tube in a large diesel engine, and an exhaust gas system for applying the method in practice, in which the silencer unit includes a substantially hollow, preferably cylinder formed body member, inside of which a set of sound silencing porous elements can be fitted, said elements including a flow channel for the exhaust gases and being arranged in successive order in the flow direction of the exhaust gases longitudinally of the body member so that the exhaust gases are led through the flow channel of each element one after the other. Said elements are installed inside the body member in the axial direction from one end thereof one at a time and are supported to the inner mantle surface of the body member. In the flow direction upstream of the body member the exhaust tube is provided with means for feeding a medium containing ammonium, urea or the like reagent applicable for catalytic depuration into the exhaust gases.

Abstract: The exhaust pipe of an engine has a double-wall structure consisting of an inner pipe and an outer pipe, and the inner pipe is spaced from the outer pipe with a predetermined clearance (heat insulating layer). The exhaust pipe includes a fitting for connecting other parts. At this fitting portion, the outer pipe has a outer hole. Likewise, the inner pipe has an inner hole. A nipple is situated on the outer pipe around the edge of the outer hole and is fixed to the outer pipe. An oxygen sensor is fitted to the nipple, and it extends through the inner hole of the inner pipe. A seal which is provided between the oxygen sensor and the flat portion of the inner pipe slidably contacts the step and the flat portion such that the fitting is unaffected by unequal thermal expansion between the inner and outer pipes.

Abstract: Disclosed herein is an internal combustion engine including a reactor including opposed first and second ends, an outer shell extending between the opposed ends, and a flow path extending between the opposed ends and including an entry opening at the first end, and a discharge opening at the second end, and an engine member including a plurality of spaced combustion chamber portions each including an exhaust port, an exhaust manifold communicating with the exhaust ports and with the entry opening and including a generally vertically extending open side including a portion closed by the reactor outer shell, and an outer wall spaced from the open side of the manifold and also engaging the outer shell of the reactor.

Abstract: The present invention is particularly applicable to lean burn engines that produce exhaust containing insufficient amounts of unburned hydrocarbons to satisfactorily reduce NOx emissions without undermining engine performance. In the exhaust purification system, ethanol or another suitable hydrocarbon is injected into the exhaust stream at an appropriate location between the engine and the catalytic converter. A deNOx catalytic converter is positioned within the exhaust downstream from the ethanol injection point. The combination engine application, ethanol injection and suitable deNOx catalyst combine to reduce NOx to satisfactory levels without producing significant amounts of undesirable secondary nitrogen containing compounds. An oxidation catalytic converter is positioned in the exhaust downstream from the deNOx catalytic converter. The oxidation catalyst serves to convert any remaining unburned hydrocarbons into carbon dioxide and water.

Abstract: An exhaust system for an engine having at least four exhaust ports firing in sequential order. The exhaust system includes an exhaust manifold having two collector sections which extend in substantial part in parallel side-by-side relationship to provide a compact construction. Each collector section is served by a pair of branch portions that communicate with respective cylinders where the cylinders collected firing at least 270 degrees from each other to minimize the effect of the exhaust pulses from one cylinder on the other cylinders.

Abstract: A method and system for controlling the amount of secondary air introduced into a vehicle's exhaust gases in order to maintain a desired catalyst air/fuel ratio for a predetermined engine air/fuel ratio. First, a quantity of primary air flow necessary to maintain the predetermined engine air/fuel ratio is determined. Next, a quantity of secondary air flow necessary to maintain the desired catalyst air/fuel ratio is determined. Finally, a controller controls the amount of secondary air introduced into the vehicle's exhaust gases based on the determined quantity of secondary air flow.

Abstract: A hot pipe from an automobile manifold is shielded from other components in the engine compartment by attaching a two part shield around the pipe and clamping it in place. Each part is formed of two sheets of metallic material sandwiching therebetween a fibrous layer of heat insulating material. The layers of each of the shield parts are formed to a shape to conform to the shape of the hot pipe to be shielded prior to installation.

Abstract: A mixture of hydrogen and air is introduced onto the face of the catalytic monolith of a catalytic converter in the exhaust line of a cold internal combustion engine. The hydrogen spontaneously combusts, thereby pre-heating the catalytic converter. Pre-heating the catalytic converter significantly improves the effectiveness of the catalytic converter in eliminating undesirable emissions of the internal combustion engine. The hydrogen is preferably produced on-board the vehicle using the system. The hydrogen source may also be coupled to the internal combustion engine to be burned by the engine during startup in the absence of gasoline to minimize the production of unacceptable emissions while the catalyst is brought up to light-off temperature.

Abstract: In this DPF apparatus, the filters have large trapping areas and three-dimensionally and efficiently trap particulates contained in the exhaust gas thereby cleaning the gas and reducing the size of the apparatus. The DPF apparatus has the main filter installed in the case incorporated into the exhaust system, the sub-filter arranged in the central portion of the main filter, and the bypass cylinder interposed between these filters. The bypass valve is installed on the exhaust gas inflow side of the sub-filter to open and close the inflow port of the sub-filter. The main filter and the sub-filter are made from ceramics porous sheet filters, or comprise a nonwoven cloth made of silicon carbide fibers and a woven cloth made of ceramics long fibers chosen from Si-C and Si-C-Ti-O long fibers and arranged adjacent to and downstream of the nonwoven cloth. The mesh heaters are laminated over the main filter on the exhaust gas inflow side.

Abstract: A method and a device are disclosed for catalyst emission control including an electrically heated startup catalyst which is positioned adjacent a main catalyst in the exhaust pipe associated with the engine. Also provided are a source of current, a switch, a control unit, a lambda sensor, and an electrically operated air pump including and air channel inserted between the lambda sensor and the startup catalyst. In connection with startup of the engine the startup catalyst and/or the air pump are activated by means of the control unit. The invention provides improved purification of the exhaust gases emitted by the engine.

Abstract: A diagnosis apparatus for diagnosing a catalytic converter of a motor vehicle as to whether the catalyst suffers deterioration by estimating a temperature of the catalyst or that of the exhaust gas in the vicinity of the catalyst on the basis of a plurality of engine parameters to thereby decide deterioration of the catalyst by using as an index the estimated temperature. The apparatus includes a unit for estimating the temperature of the catalyst in a steady state by making use of an engine speed and an engine load which represent typical parameters employed in fuel injection control of the engine. The steady-state temperature facility is realized by storing the engine speeds and the engine loads obtained experimentally in the steady state operation of the engine in the form of a two-dimensional data map.

Abstract: An exhaust gas purification system for an internal combustion engine is herein disclosed which comprises an exhaust system having an adsorption flow path provided with an adsorbent capable of adsorbing harmful components such as hydrocarbons in an exhaust gas, and a catalyst flow path provided with at least one catalyst for decreasing the harmful components in the exhaust gas, the exhaust gas purification system being characterized in that an outlet of the adsorption flow path is joined to the catalyst flow path at a predetermined position on the upstream side of the catalyst to form a joint portion; the exhaust gas produced at least at the time of the operation start of the internal combustion engine is divided so as to flow through both the adsorption flow path and the catalyst flow path in a predetermined ratio, so that part of harmful components such as the hydrocarbons are adsorbed by the adsorbent in the adsorption flow path; and when the adsorbed harmful components begin to desorb from the adsorbent wi

Abstract: A conversion efficiency of a catalyst is estimated by a correlation function concerning output signals of upper and down stream side air fuel ratio sensors. The conversion efficiency is measured by comparing the correlation function and a complementary value of the correlation function with a comparing standard value.