Abstract: A system and method for compensating for variation in a signal generated by an exhaust gas sensor include determining local maxima and minima of the signal, determining an average difference between local maxima and adjacent local minima, determining an average of the local maxima and an average of the local minima, and modifying at least one parameter based on the average difference, the local maxima average, and/or the local minima average to compensate for variation of the signal generated by the exhaust gas sensor. The modified parameter may include a switching value used to count switches of the sensor signal for monitoring catalytic converter performance or a closed loop fuel control gain value. A sensor switch may be counted for each time period having a difference between an adjacent or consecutive maximum and minimum which exceeds the switching value. Switch ratios are maintained based on both a nominal switching value and the adaptive switching value.

Abstract: A fuel metering control system for an internal combustion engine having a plurality of cylinders. The system includes an air/fuel ratio sensor and engine operating condition detecting means for detecting engine operating conditions at least including engine speed and engine load. The basic quantity of fuel injection is determined by retrieving mapped data according to the engine speed and engine load. An adaptive controller is provided to calculate a feedback correction coefficient to correct the quantity of basic fuel injection such that the detected air/fuel ratio is brought to a desired value. The desired air/fuel ratio is corrected by a second air/fuel ratio sensor installed downstream of a catalytic converter.

Abstract: A particulate and exhaust emission control system for a vehicle (10) having a diesel engine (12). The control system has a particulate trap (24) connected to the exhaust manifold (22) of the diesel engine, an additive tank (30) for storing a fuel additive decomposed by the engine's combustion process to form a reducible metal oxide capable of depressing the ignition temperature of the carbon particulates collected by the particulate trap (24) and a metering mechanism (34) responsive to the adding of diesel fuel to the vehicle's fuel tank (28) to add a quantity of the fuel additive to the diesel fuel in the fuel tank (28) to maintain a predetermined ratio of the fuel additive to the diesel fuel in the tank. The metal oxide depressing the ignition temperature of the carbon particulates collected by the particulate trap (24) to a temperature obtained by the particulate trap during selected operating parameters of the diesel engine (12).

Abstract: In a horizontally opposed type engine, right and left exhaust pipes are provided for right and left cylinder banks, respectively and a collecting pipe is disposed to collect gases these two exhaust pipes. Further, in a two-stage catalytic converter system, two main catalysts are provided for the two exhaust pipes, respectively, and a subsidiary catalyst is provided in the collecting pipe. An oxygen sensors is provided in each of the exhaust pipes on the upstream side of it's main catalyst. The air-fuel ratios of both the banks are controlled simultaneously on the basis of the output of one of the sensors, and the air-fuel ratio of the other bank is corrected on the basis of a difference between the outputs of the two oxygen sensors. Accordingly, the air-fuel ratios of both right and left banks can be controlled appropriately, without the use of an auxiliary oxygen sensor. As a result, it is possible to improve the purification capability of the auxiliary catalyst in the collecting pipe.

Abstract: In the present invention, the exhaust gas from the engine is divided into a first and a second branch exhaust passages after it passes through a three-way reducing and oxidizing catalyst, and the two branch exhaust passages merge into an exhaust gas outlet passage. In the first branch exhaust passage, an oxidizing catalyst is disposed, and in the exhaust gas outlet passage, a denitrating and oxidizing catalyst is disposed. NO.sub.x in the exhaust gas from the engine is all converted to N.sub.2 and NH.sub.3 by the three-way reducing and oxidizing catalyst and a part of the NH.sub.3 generated by the three-way catalyst flows into the first branch exhaust passage and is converted to NO.sub.x again by the oxidizing catalyst. The amount of NO.sub.x produced by the oxidizing catalyst and the amount of NO.sub.x flowing through the second branch exhaust passage is determined by the flow distribution ratio of the first and the second branch exhaust passages.

Abstract: An engine control computer estimates NO.sub.x trap temperature based on an estimated midbed temperature of a three-way catalytic converter located upstream from the trap and the effect on NO.sub.x trap temperature of introducing air into the exhaust upstream of the trap during purging of the trap.

Abstract: A detecting apparatus for a catalytic converter has a pair of O.sub.2 sensors, arranged individually on the up- and downstream sides of the converter, and an electronic control unit for discriminating reduction of the purifying capacity of a three-way catalyst in the converter. This unit discriminates the reduction of the purifying capacity in accordance with the comparison between a decision value and the ratio between the respective frequencies of outputs from the O.sub.2 sensors. In the case where the O.sub.2 sensor on the upstream side is subject to thermal degradation, its decision value is corrected, or the decision itself is interrupted.

Abstract: A method, and an apparatus for carrying out the method, for purifying exhaust gases from internal combustion engines is provided. The engines having a catalyzer system which includes a first catalyzer and at least one second catalyzer, arranged downstream of the first catalyzer, for the conversion of HC, CO and NO.sub.x exhaust gas constituents. Exhaust gases flow through both catalyzers during the entire operating period of the engine. The first catalyzer is suitable for at least the catalytic conversion of HC and CO exhaust gas constituents. In a first step of the method, the first catalyzer is operated over-stoichiometrically during the cold starting phase in order to reduce the HC and CO emissions and, in a second step of the method with .lambda.-controlled stoichiometric exhaust gas composition, the catalytic conversion of the exhaust gas in the first catalyzer is at least largely de-activated and takes place in the second catalyzer.

Abstract: A diagnostic equipment for an exhaust gas cleaning apparatus installed for an engine, comprising a misfire detector which detects the misfire of the engine, and a secondary-air-system failure detector which detects the failure of a secondary air system. An index corrector corrects a deterioration index calculated by a deterioration-index calculator, in accordance with the detected result of the detector. A deterioration decision unit decides if the diagnostic equipment has failed, by the use of the corrected deterioration index. In a case where the extent of the misfire or the like is severe, a decision interrupter interrupts the decision of the deterioration decision unit. Thus, even when the misfire of the engine or the failure of the secondary air system has occurred, the detection of the deterioration of a catalyst does not err. It is therefore avoided to erroneously replace the catalyst which has not deteriorated yet, or to run the engine in spite of the deterioration of the catalyst.

Abstract: A water jacketed exhaust pipe comprising an inner liner, an outer shell, and a spray ring. The inner liner includes an internally tapered section which clips the turbulence that occurs along the inner walls of the liner. As a result, fluid expelled from the spray ring will not migrate into the inner liner where it can cause severe corrosion. The inner liner is longer than the outer shell. The outer liner includes an internally tapered section which scatters the stream of water expelled from the spray ring and further redirects water onto the inner liner and into the center of the exhaust path. The redirected water particles are easily vaporized and in the process, extract a significant amount of heat from the exhaust system.

Abstract: A diagnostic apparatus for exhaust gas clarification apparatus for internal combustion engine is disclosed. The diagnostic apparatus can diagnoses the individual catalyst independently by means that an air/fuel ratio sensor is mounted before and after the individual catalyst, and that the individual catalyst is diagnosed by estimating the correlation of the output signals from the air/fuel ratio sensors mounted before and after the individual catalyst, and furthermore, that the individual diangosis operation is performed at distinctive operation regions adequate for their corresponding diagnostic mode.

Abstract: In the present invention, a NO.sub.x absorbent is used for removing the NO.sub.x in the exhaust gas. The NO.sub.x absorbent absorbs NO.sub.x in the exhaust gas when the air-fuel ratio of the exhaust gas is lean, and releases the absorbed NO.sub.x and reduces it to nitrogen when the air-fuel ratio of the exhaust gas is rich or stoichiometric. To prevent the NO.sub.x absorbent from being saturated with the absorbed NO.sub.x, the NO.sub.x absorbent must be regenerated periodically by causing the NO.sub.x in the absorbent to be released and reduced. However, it is found that when the regenerating process by supplying a rich air-fuel ratio exhaust gas to the NO.sub.x absorbent is carried out at high NO.sub.x absorbent temperature, a part of NO.sub.x flows out from the NO.sub.x absorbent at the beginning of the regenerating process without being reduced. In the present invention, this outflow of NO.sub.x is suppressed by, for example, carrying out the regenerating process only when the temperature of the NO.sub.

Abstract: An apparatus for cleaning exhaust gases of solid particles comprises a rotational combustion chamber (1), a swirler (2) and a soot collector (3) separated from one another by a separating cavity (7) and located on the same axis downstream the gas flow. A catalytic unit (4) for neutralizing harmful gaseous emissions is arranged coaxially inside the soot collector (3). The apparatus is provided with an inlet pipe (8) and an outlet pipe (9). The swirler is made in the form of an impeller. The unit (4) for neutralizing harmful gaseous emissions is made in the form of a cylindrical body (5) comprising longitudinal channels (6) with a catalytically active internal layer applied-thereto. The longitudinal channels (6) have a curvilinear closed-type shape in their cross-section and the catalytically active layer has the same thickness over the entire internal surface of the longitudinal channels (6), which thickness is uniform both over the cross-section of the unit (4) and throughout its length.

Abstract: In the exhaust gas purification device of the present invention, a NO.sub.x absorbent is disposed in the exhaust gas passage of a diesel engine. At the time when NO.sub.x should be released from the NO.sub.x absorbent, a control circuit of the engine reduces the excess air ratio of the engine, and switches the combustion mode of the engine from the normal diesel combustion, in which diffusive combustion is dominant in the combustion chamber of the engine, to the combustion mode in which pre-mixture fuel combustion is dominant. By doing this, it is possible, even in a diesel engine, to reduce the excess air ratio in combustion to thereby make the air-fuel ratio of the exhaust gas lower than or equal to the stoichiometric. Thus, the regeneration of the NO.sub.x absorbent can be performed even when it is applied to a diesel engine.

Abstract: A deterioration diagnostic apparatus for a three-way catalyst includes an electronic control unit, which obtains a frequency of reversals of the changing direction in which the output of an upstream-side O.sub.2 sensor changes, based on the number of times the output voltage of the O.sub.2 sensor crosses a threshold. Also, the control unit obtains a frequency of reversals of the changing direction in which the output of a downstream-side O.sub.2 sensor changes, based on the number of times the output voltage of the downstream-side O.sub.2 sensor crosses upper and lower reversal reference values which are obtained by adding and subtracting a hysteresis constant to and from an average value of input values of the downstream-side O.sub.2 sensor output voltage.

Abstract: A multi-pass catalytic converter/muffler uses a single catalytic support bed without increasing the overall size of the catalytic converter/muffler. The outer surface area of the catalytic support bed is disposed adjacent to the outer wall of the catalytic converter housing, with only the mat in between. Secondary air may be provided upstream before the exhaust gases make their first pass through the catalytic support bed, or after the first pass but before the second pass or even after the second pass.

Abstract: The effectiveness is prolonged for catalytic oxidizers to reduce emissions of both HC and CO from two-stroke gasoline engines. A compound of a platinum group metal is added to the cylinder of the engine, to make it available as an active oxidation catalyst by combustion of the fuel. Preferably, the platinum group metal compound is added with the lubricating oil, but can be added to the fuel or through a separate injection.

Abstract: An engine exhaust purifying device is positioned at a connection between an exhaust pipe and an expanded pipe, which is located upstream of an oil reservoir and below an engine, and includes an outer pipe and an inner pipe joined together to form a dual-pipe structure, the outer pipe being weld connected at its reduced-diameter portion to a fuse connection portion of the inner pipe, the fuse connection portion carrying no ventholes and a catalyst layer thereon and the exhaust purifying device being enclosed by a heat insulating protector.

Abstract: An exhaust collector for collecting exhaust gases from a multiple cylinder combustion engine to a common flow includes primary tubes. To reduce mass and heat losses in the exhaust system, the peripheral walls of the collector are at least to a substantial part formed by the primary tubes.

Abstract: A management system of an engine having a hot operating system (a catalytic converter or fuel vaporiser) and a rapid heating system for the hot operating system includes a clock and means to operate the clock after the engine has stopped where the clock operates to issue a signal indicating the time since the last engine switch off. An estimator is coupled to the clock for estimating the temperature of the hot operating system prior to restarting the engine on the basis of signals from the clock indicating the time since last engine switch off and a heating system controller controls the rapid heating system in dependence upon the estimated temperature of the hot operating system prior to restarting the engine.