Abstract: The invention concerns a method and device for removing particles, in particular soot particles, from exhaust gases produced by internal-combustion engines. The invention calls for the particles to be electrostatically charged by an electrode (4). The particles or particle agglomerates are trapped by a fine-mesh metal filter (5). The conducting material (5a), preferably a sintered ferritic metal, of which the filter (5) is made can also be used as a collecting electrode. A high voltage (6) is applied (7, 10) to the electrodes. At intervals, preferably at regular intervals, an electric current is passed (11, 12) through the filter (5), causing the filter material (5a) to heat up to a temperature above the ignition temperature of the particles. The preferred shape of the filter surface is a cylinder, truncated cone and/or cone.

Abstract: A control system for an internal combustion engine equipped with a catalytic converter including an exhaust gas purifying catalyst. The control system comprises a catalyst deterioration diagnosing device for diagnosing the deterioration condition of the catalyst. The operation of the catalyst deterioration diagnosing device is avoided when a first frequency at which an engine operating condition shifts to a range for stopping fuel supply to a fuel injector valve becomes larger by not less than a predetermined value than a second frequency at which the engine operating condition shifts to a range for increasing the amount of the fuel supply, thereby preventing the catalyst deterioration diagnosis from being carried out under a condition in which the catalyst is subjected to a high temperature and lean (air-fuel ratio) atmosphere.

Abstract: Provided is an internal combustion engine malfunction diagnosis apparatus capable of diagnosing the deterioration of an internal combustion engine with a high accuracy and capable of diagnosing deterioration of a fluctuation factor detection section of the engine with a high accuracy in irrespective of the engine speed.

Abstract: A control system controls an electrically heated catalyst for purifying exhaust gases emitted from an internal combustion engine. Voltage applied to the electrically heated catalyst and electric current flowing through the same are detected. A changeover is made between supply and interrupt of power to the electrically heated catalyst. A parameter indicative of an operative state of the electrically heated catalyst is calculated based on the detected voltage and the detected current, and the operative state of the electrically heated catalyst is detected based on the parameter. The changeover between the supply and interrupt of power to the electrically heated catalyst is controlled based the operative state of the electrically heated catalyst thus detected.

Abstract: An adsorbing capacity determining apparatus is provided for determining the adsorbing capacity of an unburned component adsorbing device in an exhaust system for an internal combustion engine. The adsorbing capacity determining apparatus comprises upstream and downstream air-fuel ratio detectors, respectively coupled upstream and downstream from the unburned component adsorbing device, a temperature sensor for sensing the temperature of the unburned component adsorbing means and a computer for determining the adsorption capacity as a function of the outputs of the system and downstream air-fuel ratio detectors, when the temperature is within a predetermined range.

Abstract: A method, including an amplitude evaluation of control oscillations of the oxygen content of the exhaust gas of an internal combustion engine in front of and behind a catalytic converter, for judging the operating condition of the converter in order to determine whether the performance of the catalytic converter has deteriorated past a predetermined point. As soon as this condition is detected using the amplitude evaluation, switching is effected to the frequency evaluation for judging the functioning of the catalytic converter.

Abstract: An exhaust gas purification device comprising a three way catalyst, an oxidizing catalyst and a NOx absorbent which are arranged in this order in the exhaust passage. A rich air-fuel mixture is burned in the combustion chamber, and secondary air is supplied upstream of the three way catalyst so as to make the air-fuel ratio of the exhaust gas flowing into the three way catalyst a rich air-fuel ratio greater than the air-fuel ratio of the air-fuel mixture burned in the combustion chamber. Further, secondary air is supplied upstream of the oxidizing catalyst to make the air-fuel ratio of the exhaust gas flowing into the oxidizing catalyst and the NOx absorbent slightly leaner than the stoichiometric air-fuel ratio.

Abstract: The catalytic muffler for small internal combustion engines has a venturi with a flattened profile formed from two stamped pieces, namely the muffler housing and the separator plate. This design eliminates the need for a separate piece of tubing or machined part, as is required in prior art round venturi devices. The catalytic muffler also includes a noise attenuator disposed upstream of the catalyst, thereby eliminating the back pressure which is otherwise applied to the venturi when the noise attenuator is disposed downstream of the catalyst. In addition, back pressure on the venturi is reduced by sizing the port in the separator plate and the exhaust port so that their respective cross sectional areas are substantially equal to the cross sectional area of the catalyst.

Abstract: There is provided an improved core element for use in converters, especially catalytic converters. The core is characterized by two portions one of which portions is capable of being electrically heated, and the other of which is isolated from the first portion electrically and thermally and is called a light-off portion. A plurality of core elements is wrapped about a central rigid metallic pin and the assembly tightly spirally wound about the pin to form the core, part of which is electrically heatable and the other of which is not heated electrically. The core is formed from a plurality of composite core elements, each including a corrugated strip backed up with a flat two-member strip, one band of the two-member flat strip being of generally relatively narrow width, contiguous with the leading portion of the corrugated strip, and the other band contiguous with the trailing portion of the corrugated strip and usually being of relatively greater width.

Abstract: There is provided an air-fuel ratio control system for controlling the air-fuel ratio of a mixture supplied to an internal combustion engine having an exhaust passage. The system includes upstream and downstream exhaust gas component concentration sensors arranged in the exhaust passage at respective locations upstream and downstream of a catalytic converter, for detecting concentration of a component contained in exhaust gases. Feedback control of the air-fuel ratio of the mixture is carried out based on a value of a control parameter set based on an output from the downstream exhaust gas component concentration sensor and an output from the upstream exhaust gas component concentration sensor. An inversion period is detected with which the output from the upstream exhaust gas component concentration sensor is inverted from one side to another side with respect to a predetermined level during the feedback control of the air-fuel ratio.

Abstract: A method and apparatus for actuating a direct source exhaust gas capture system for capturing and exhausting exhaust from a vehicle tailpipe which automatically starts when the ignition system of the vehicle is actuated prior to the engine starting, and which is operable to automatically restart when the vehicle returns to the vehicle storage facility.

Abstract: The method reduces the nitrogen oxide concentration in the exhaust of an internal combustion engine. A noticeable reduction in the NO.sub.x emission of a diesel motor can be achieved by applying the Selective Catalytic Reduction (SCR) method. In this method, ammonia is injected into a catalyzer through which the exhaust gas flows, this ammonia reacting with nitrogen monoxide or, respectively, nitrogen dioxide to form nitrogen and water. Since the exhaust gas should contain neither nitrogen monoxide nor excess ammonia, suitable methods are required for regulating the metering of NH.sub.3. For controlling the amount of urea added to the exhaust gas as a reduction agent, the NO and NH.sub.3 concentration is measured using a detector located in the exhaust systems following the SCR catalyzer. The detector contains a vanadate layer manufactured on the basis of a specific sputtering method as a sensitive element.

Abstract: A mechanism for computing the basic ignition period of a spark plug from engine running conditions, a mechanism for judging whether or not the running conditions are within a delay correction region, and a mechanism for computing a basic delay amount if the running conditions are within the delay correction region, are provided. The accelerator opening or throttle opening are detected, and after the delay amount has been corrected according to the detected opening, the basic ignition period is corrected by the basic delay amount. The spark plug thereby ignites the fuel with the corrected ignition period, and the engine catalyst is activated early without impairing engine running performance after engine start-up.

Abstract: With an air-fuel ratio control apparatus for an internal combustion engine wherein oxygen sensors are respectively arranged upstream and downstream of an exhaust gas purification catalytic converter, air-fuel ratio feedback control is carried out for diagnosis using only the downstream oxygen sensor. When during diagnostic air-fuel ratio feedback control, phase differences of output fluctuations of the two oxygen sensors are below a predetermined value, deterioration of the catalytic converter is judged. A judgment level is variably set based on the results of the deterioration diagnosis of the catalytic converter, and deterioration of response of the downstream oxygen sensor is diagnosed by comparing the output-period of the downstream oxygen sensor with the set judgment level.

Abstract: A catalyst deterioration-determining device for an internal combustion engine, in which a temperature sensor for detecting the temperature of a catalyst body is eliminated, but high-precision determination can be made to the deterioration of the catalyst body. To this end, a control unit determines, on the basis of a warm-up counter used for a catalyst body, whether or not the catalyst body is in a predetermined warm-up state. The warm-up counter reckons in relation to any engine load of an internal combustion engine. If the catalyst body is found to be in the predetermined warm-up state according to the above determination, the control unit determines whether or not deterioration-determining conditions for the catalyst body have been fulfilled.

Abstract: A process for treating an engine exhaust gas stream is disclosed. The process involves arranging a catalyst bed and a molecular sieve bed side by side with a connecting pipe between and parallel to the two beds. When the engine is first started, the cool exhaust is flowed through the catalyst bed, then through the connecting pipe, then through the molecular sieve bed and finally discharged to the atmosphere. When the molecular sieve bed reaches a temperature of about 150.degree. C. to about 200.degree. C. the exhaust stream is diverted such that it is first flowed through the molecular sieve bed, to desorb the adsorbed hydrocarbons, and then through the catalyst bed and finally discharged to the atmosphere. Finally, when all the hydrocarbons are desorbed from the molecular sieve bed, the exhaust stream is diverted such that it is flowed through the catalyst bed and then discharged to the atmosphere.

Abstract: A catalyst deterioration determination is performed in two stages. In the first stage of determination, an amplitude of an output signal from a downstream oxygen sensor is detected and this amplitude is compared with a reference value in order to determine possible deterioration in a catalyst. When correct performance is expected, while taking into account variations (amplitude and response) in the upstream and downstream oxygen sensors, then the detection in a second stage is omitted. However when possible catalyst deterioration may be present, the determination at the seconds stage is performed. After adjusting the response of the upstream oxygen sensor to the characteristic of the slowest response, the total response delay time of the downstream sensor is obtained within a specified amount of time, and this sum then is compared with a reference value indicating catalyst deterioration. A final determination is made as to whether catalyst deterioration is present.

Abstract: An air-fuel ratio control system for an internal combustion engine is provided. This system has an upstream air-fuel ratio sensor arranged upstream of a catalytic converter and a downstream air-fuel ratio sensor arranged downstream thereof, and learns a given feedback control parameter upon reversal of an air-fuel ratio between rich and lean sides based on the downstream air-fuel ratio sensor. The system also learns the given feedback control parameter when preselected conditions are met even if the air-fuel ratio is not reversed. Additionally, the system, when brought under open-loop control from feedback control, stores the given control parameter. Upon resumption of the feedback control, when the air-fuel ratio shows the same status, the stored given control parameter is used. Further, the system controls the air-fuel ratio based on the output from the downstream air-fuel ratio sensor when it moves out of a preselected range.

Abstract: A method for monitoring a system for delivering secondary air to an exhaust tube of an internal combustion engine. In the method a secondary air pump is switched on and builds up a pressure on the inlet side of a blocking valve which is normally closed and not being acted upon. The blocking valve has a valve closing member that is acted upon by a predetermined closing force of an elastic element. If the secondary air quantity pumped by the secondary air pump reaches a certain minimum air quantity and pressure, then with the then-opened blocking valve, a lambda sensor disposed in an exhaust tube detects a change in the lambda value in the exhaust tube that exceeds a predetermined threshold value. The method is suitable for monitoring the function of a system for delivering secondary air to the exhaust tube of an internal combustion engine.

Abstract: A diagnostic system in which the accuracy of the diagnosis of the deterioration state of a catalyst in a catalytic converter for cleaning the exhaust gas of an internal combustion engine is enhanced without incurring a rise in cost. The temperature of the catalyst is estimated using the operating-state signal (for example, the flow rate of intake air or the width of a fuel injection pulse) of the engine by a diagnostic device. The conversion efficiency of the catalyst calculated from the outputs of oxygen sensors is corrected using the estimated temperature by the diagnostic device. The deterioration state of the catalyst is diagnosed on the basis of the corrected temperature by the diagnostic device.