Abstract: Methods and apparatus are provided for monitoring the performance of a hydrocarbon trapping device which removes hydrocarbons from an engine exhaust stream during cold startup conditions before the catalyst has reached its light-off temperature. The electronic engine controller which provides conventional fuel control functions is used to numerically integrate sensed values during a predetermined time interval in the engine's startup period. The sensed values indicate the rate at which hydrocarbons are being retained or purged by the trap, and the result of the integration indicates the total amount of hydrocarbon molecules trapped or purged. The integration result values may be retained for future readout during diagnostic procedures, and the result values may be compared with a threshold value to generate an alarm indication whenever the integration result value indicates that the trap is not performing satisfactorily.

Abstract: Nitrogen oxides are removed from the exhaust of an internal combustion engine which operates on a methane-containing fuel by reacting the nitrogen oxides and oxygen in the exhaust gas with a controlled amount of methane in the presence of a reducing catalyst. The catalyst preferably comprises a crystalline zeolite having a silicon to aluminum ratio of equal to or greater than about 2.5 which is prepared from a non-acid zeolite which is ion exchanged with a cation selected from the group consisting of cobalt, nickel, iron, chromium, and manganese. Methane for the reaction is provided as a portion of the methane-containing fuel. Carbon monoxide present in the exhaust gas is converted to carbon dioxide simultaneously with the reduction of nitrogen oxides.

Abstract: An emission control system including an auxiliary catalytic converter (50) coupled upstream of a main catalytic converter (44) via a bypass valve (52). Exhaust gas flow is first routed through the auxiliary converter (50) by opening one bypass valve (52) and closing another (48) when an indication of exhaust gas temperature is above a predetermined temperature. An indicating signal is derived from transitions in output of an exhaust gas sensor (58) position downstream of the auxiliary converter (50). Degraded operation of the auxiliary converter (50) is provided when both the indicating signal indicates degraded operation and an indication of inducted airflow exceeds a preselected airflow (324). Degraded operation of one bypass valve (48) is provided when the indicating signal indicates degraded operation and the inducted airflow is below the preselected airflow (340-354).

Abstract: The present invention is particularly well suited for purifying exhaust from relatively large lean burn diesel engines. A computer controlled injector intermittently injects an optimal amount of NOx reducing fluid into the exhaust passageway from the engine. The optimal amount corresponds to an amount that will achieve optimal NOx reduction rates for the given engine operating condition and exhaust temperature. A computer periodically senses the engine operating condition and the exhaust temperature, and calculates the appropriate injection amount. With appropriate deNOx and oxidation catalysts located downstream from the injector, the exhaust purification system of the present invention has the ability to greatly reduce NOx content of the exhaust while maintaining HC emissions at acceptable levels.

Abstract: An exhaust system for a spark ignition engine on an automotive vehicle including an exhaust filter disposed downstream of a spark ignition engine for condensing hydrocarbons in exhaust gases from the engine during a first time period after start of the engine, a bypass structure for bypassing at least a portion of exhaust gases around the exhaust filter to heat the exhaust filter during a second time period after the first time period and evaporate the condensed hydrocarbons, and a catalytic converter disposed downstream of the exhaust filter to oxidize the evaporated hydrocarbons and reduce NO.sub.x in exhaust gases passing therethrough. A method is also provided.

Abstract: In an exhaust gas purification system for an internal combustion engine including a catalytic converter disposed in an exhaust pipe, an apparatus for controlling an amount and temperature of fresh air fed into the exhaust pipe so that optimal purification efficiency of the catalytic converter can realized. The apparatus includes an air pump for taking in fresh air, a control valve for controlling air flow, a heater for heating the air and the controller for controlling the pump, the valve and the hater in dependence on engine operation states so that nitrogen oxides, carbon monoxide and hydrocarbon contained in the exhaust gas can be removed to a maximum through reduction and oxidation reactions. An abnormality detecting device detects occurrence of abnormality in the air feeding control apparatus for ensuring fail-safe operation thereof.

Abstract: An apparatus is provided for purifying an exhaust gas discharged from an internal combustion engine, which comprises a first exhaust gas passage including a nitrogen oxide removing catalyst and a three way catalyst, a second exhaust gas passage including the three way catalyst, a gas flow regulator for selectively directing the exhaust gas to the first and second exhaust gas passages, and a control unit which directs the exhaust gas to the first exhaust gas passage (thereby passing exhaust gas first through the nitrogen oxide removing catalyst and thereafter through the three way catalyst) when the temperature of the nitrogen oxide removing catalyst is within a hydrocarbon adsorbing range of temperature thereof while the engine is warming up, and to the second exhaust gas passage (thereby passing the exhaust gas only through the three way catalyst) when the temperature of the nitrogen oxide removing catalyst exceeds the hydrocarbon adsorbing range of temperature thereof.

Abstract: An exhaust afterburner for positioning in an exhaust duct or the like of an internal combustion engine through which partially reacted gases are circulated is disclosed. The exhaust afterburner includes a venturi induction member which has a circumferential array of radially extending apertures for inducting a reacting gas into the exhaust duct upon passage of the partially reacted gases therethrough. A housing surrounds a venturi induction member and includes a first air intake opening in communication with the apertures of the venturi induction member as well as a second air intake opening disposed adjacent to the inlet end of the venturi induction member. A bushing is positioned within the housing at the second air intake opening with the bushing having a circumferential array of radially extending apertures in fluid communication with the second air intake opening. A mechanism for relieving back pressure is provided within the exhaust afterburner positioned within the exhaust afterburner housing.

Abstract: An air/fuel control system (8) and method for an engine (28) having two engine banks coupled to a single catalytic converter (50). First and second exhaust gas oxygen sensors (44, 55) are coupled to respective first and second exhaust manifolds (56, 57). A feedback signal is generated by a PI controller responsive to an average (104-120) of the first and second sensor outputs (44, 45). An adjustment signal is generated (440-448) by another PI controller responsive to a difference between the first and second sensor outputs (44, 45). Fuel delivered to the first engine bank (300a-306a) is adjusted by a first modified feedback signal generated by adding the adjustment term to the feedback signal (450-454). And, fuel delivered to the second engine bank (300b-306b) is adjusted by a second modified feedback signal generated by adding the adjustment term to the feedback signal (460-462).

Abstract: A combustion state-determining system for an internal combustion engine has an ECU which determines a misfiring state of the engine, and calculates a misfiring rate of the engine, based on the result of the determination of the misfiring state. A catalyst temperature sensor detects the temperature of a catalytic converter as the exhaust system temperature, and the ECU determines the combustion state of the engine, based on the detected exhaust system temperature and the calculated misfiring rate. A combustion state control system restrains the output from the engine, based on the determination result of the combustion state-determining system.

Abstract: A catalytic treatment device diagnostic for an automotive exhaust system having at least two catalytic treatment devices wherein reduced oxygen storage capacity of each of the devices may be diagnosed without significant loss in engine air/fuel ratio control precision by varying the source of an actual air/fuel ratio feedback signal from a sensor positioned upstream of the devices during normal operation to a sensor mounted downstream of at least one of the devices during a diagnostic period. Measurable change in the oxygen content of exhaust gas passing through each of such devices then becomes available for analysis during the diagnostic period.

Abstract: The invention relates to an exhaust system for a W-12 reciprocating piston internal combustion engine with three rows of cylinders of four cylinders each, with outlet channels connected to the exhaust lines, in which there are two separate exhaust runs to which two cylinders per row of cylinders are connected in order to achieve a functional, structurally favorable system.

Abstract: A power device for driving an auxiliary equipment for an internal combustion engine capable of driving both a fuel injection unit and a valve without specifically providing a adjusting valve when the engine includes no battery acting as a power supply. A generator driven by the internal combustion engine is provided therein with a generating coil for driving the auxiliary equipment which is common to both a pump motor and an actuator. A driving power feed circuit is arranged for feeding driving power to the pump motor and actuator from the generating coil for driving the auxiliary equipment which acts as a power supply. The driving power feed circuit includes a pump driving switch for switching a driving current of the pump motor, an actuator driving switch for switching a driving current of the actuator, and a switch control unit for turning on the pump driving switch and actuator driving switch at duty ratios different from each other, respectively.

Abstract: An internal combustion engine has an adsorber arranged in the exhaust passage for adsorbing unburnt components in exhaust gases, and an exhaust gas-purifying device arranged in the exhaust passage at a location downstream of the adsorber. The exhaust gas-purifying device is equipped with a heater. An ignition timing of an internal combustion engine is retarded when the engine is started at a low engine temperature. The retardation of the ignition timing is restrained over a time period from the start of the engine to a time point the exhaust gas-purifying device is warmed up to a predetermined activated condition.

Abstract: An exhaust gas purifying system for an automobile engine is equipped with a metal zeolite catalytic converter for deoxidizing and purifying nitrogen oxides in exhaust gas. The system controls and compulsorily changes the air-fuel ratio of the fuel mixture injected into the automobile engine based on a target air-fuel ratio only when the temperature of the exhaust gas, before entering the catalyst, is greater than a specific temperature.

Abstract: An engine air/fuel control system is shown (300-428) responsive to a feedback variable derived (410-428) from an exhaust gas oxygen sensor (16) positioned upstream of a catalytic converter (20). A non-catalytic exhaust gas oxygen sensor (24) having a non-catalytic electrode (490) positioned in the engine exhaust downstream of the converter (20) is coupled to a current pumping circuit (28). Current is pumped into an electrode of the downstream sensor (24) shifting its output step change towards richer air/fuel ratios. Pumping current is gradually increased in amplitude until the downstream sensor (24) incurs a change in its output state (602-634). The pumping current occurring at the time of such change in output states provides a measurement of catalyst efficiency.

Abstract: In an engine exhaust emission control system, a ternary catalyst and a hydrocarbon adsorber are provided in an exhaust passageway from an engine. The ternary catalyst includes first passages through which an exhaust gas discharged from the engine flows, and second passages through which the exhaust gas which has flowed through the first passages and the hydrocarbon adsorber flows. The first and second passages are laminated to each other to enable heat exchange therebetween. The hydrocarbon adsorber is capable of being cooled by a cooling medium. Thus, it is possible to reliably prevent hydrocarbons in the exhaust gas from being released to the atmosphere during the cold start of the engine.

Abstract: A control system and method maintains engine air/fuel operation near stoichiometry (104-178) in response to exhaust gas oxygen sensors (44,52) positioned both upstream and downstream of a catalytic converter (50). A non-catalytic exhaust gas oxygen sensor (54), having non-catalytic electrode, is positioned downstream of the converter (50) and its output voltage (Vo) monitored. Pumping current (Ip) is applied to an electrode of the non-catalytic sensor at a predetermined magnitude (IPREF) from a pumping current generator (56). When the output voltage (Vo) is detected at a predetermined high voltage range (302-318) an indication of degraded converter efficiency is provided (320).

Abstract: An apparatus for reducing the amount of electrical power needed to attain light-off of a catalytic converter, particularly a catalytic converter for internal combustion engines. In addition to a resistance-heated catalytic converter, means are provided for varying the air/fuel ratio in the exhaust gas system for the purpose of reducing the ignition temperature of the exhaust gas stream, thereby further reducing the electrical energy required to attain light-off during cold-start.

Abstract: A bent portion (adsorption box) is formed in part of an exhaust pipe connecting exhaust ports and a catalyst for purifying HC or the like in the exhaust gas, and a HC adsorbent of a honeycomb structure is placed forward with respect to the direction in which the exhaust gas travels straight without turning at the bent portion. The exhaust gas flowing from the exhaust ports, turns, and flows into the exhaust pipe, but HC having a large particle size travels straight along rectifier blades to be adsorbed by the HC adsorbent and held for a while. During such process, the catalyst connected to the exhaust pipe is heated up to be activated, thereby for purifying the HC or the like which is desorbed by the temperature rise of the adsorbent. Another HC catalyst may be carried in the front of the adsorbent that is easily heated to a high temperature, or an EGR passage including an EGR control valve may be connected downstream from the adsorbent.