Abstract: A temperature sensor is disposed near an HC adsorbent in an exhaust system of an internal combustion engine. After the internal combustion engine is shut off, a deteriorated state of the HC adsorbent is evaluated based on a value of the humidity detected by a humidity sensor. The deteriorated state of the HC adsorbent is evaluated by comparing the detected value of the humidity with a threshold established depending on the temperature state near the HC adsorbent. In evaluating deteriorated state of the HC adsorbent, a change in the output characteristics of the humidity sensor depending on its temperature state is compensated for.

Abstract: An adsorbent state determining apparatus is provided for accurately determining the state of an adsorbent including a deterioration while ensuring elimination of the influence of impurities sticking on a sensor element of a humidity sensor. The adsorbent state determining apparatus determines the state of an adsorbent disposed in an exhaust system of an internal combustion engine for purifying exhaust gases. The adsorbent is capable of adsorbing hydrocarbons and moisture within exhaust gases.

Abstract: A state determination apparatus for a humidity sensor is provided for accurately determining the state of the humidity sensor, including the responsibility, from a result detected by the sensor itself. The state determining apparatus is configured to determine a humidity sensor arranged in an exhaust system of an internal combustion engine for detecting a humidity within an exhaust pipe. The apparatus comprises an ECU which determines whether or not the internal combustion engine is in a predetermined operating condition, calculates a change state parameter indicative of a change state of a value detected by the humidity sensor based on the detected value of the humidity sensor detected when the internal combustion engine is in the predetermined operating condition, and determines the state of the humidity sensor in accordance with the calculated change state parameter.

Abstract: There is provided a temperature control system for a humidity sensor, which is capable of eliminating impurities attached to a sensor element of the sensor efficiently and sufficiently while preventing the sensor element from being cracked due to heat generated by a heater in a state of condensation formed thereon, and suppressing attachment of impurities to the sensor element, thereby making it possible to preserve an excellent detection accuracy of the humidity sensor. The temperature control system controls the temperature of the sensor element of the humidity sensor arranged in an exhaust pipe for detecting humidity within the exhaust pipe. A heater heats the sensor element. The temperature of the sensor element is detected.

Abstract: An exhaust emission control system for an internal combustion engine has an exhaust passage switching device for switching an exhaust gas flow path, an HC adsorbent material disposed within the main exhaust passage for adsorbing and releasing unburned constituents in exhaust gases, and a control device for controlling the switching device such that the exhaust gas flow path is switched to the main exhaust passage when the unburned constituents is adsorbed by the HC adsorbent material, that the exhaust gas flow path is switched to the bypass exhaust passage when the unburned constituents adsorbed by the HC adsorbent material is released from the HC adsorbent material, and that the exhaust gas flow path is switched to the main exhaust passage when the release of the unburned constituents from the HC adsorbent material is completed.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine is provided for simultaneously realizing sufficient recovery of the adsorbing capability of an adsorbent and limitation to an increase in exhaust resistance. The exhaust gas purifying apparatus for an internal combustion engine comprises a flow path switching valve for switching an exhaust gas flow path to a bypass exhaust passage or to a main exhaust passage, three-way catalysts, and an HC adsorbent arranged in the bypass exhaust passage for adsorbing hydrocarbons in exhaust gases and fully desorbing the adsorbed hydrocarbons when it is heated to a full desorption temperature or higher. A troidal passage of the main exhaust passage completely surrounds a portion of the bypass exhaust passage in which the HC adsorbent is arranged. A ratio S1/S2 of the cross-sectional area S2 of the troidal passage to the cross-sectional area of a flow-in passage is set in a range from 1.

Abstract: A system for discriminating degradation of an exhaust purification system of an internal combustion engine having an adsorbent installed at a bypass exhaust gas passage adsorbing unburned HC in exhaust gas generated by the engine. Based on the assumption that the degradation of the adsorbent made from zeolite progresses or advances depending on its temperature, the temperature is detected and if it exceeds a predetermined temperature, an index indicative of the degree of degradation progress is determined based on a surplus exceeding the predetermined temperature. The index is accumulated to be compared with a threshold value and the adsorbent is discriminated to be degraded when the accumulated index exceeds the threshold value, thereby enabling to discriminate the adsorbent degradation accurately with a simple configuration.

Abstract: In an internal combustion engine having a double-structure exhaust passage comprised of an inner (bypass) exhaust passage and an outer (main) exhaust passage arranged to surround the outside of the inner exhaust passage such that exhaust gases are discharged through one of the inner and outer exhaust passages, an exhaust gas characteristic detecting apparatus is capable of reliably detecting the characteristic of exhaust gases through the inner exhaust passage. The detecting apparatus comprises a guide pipe extending across the outer exhaust passage and having an exhaust gas introducing port facing the inner exhaust passage for introducing exhaust gases flowing into the inner exhaust passage into the guide pipe, and a sensor having a sensing unit for detecting the humidity of exhaust gases and arranged such that the sensing unit is positioned in the guide pipe.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine is provided for simultaneously realizing sufficient recovery of the adsorbing capability of an adsorbent and limitation to an increase in exhaust resistance. The exhaust gas purifying apparatus for an internal combustion engine comprises a flow path switching valve for switching an exhaust gas flow path to a bypass exhaust passage or to a main exhaust passage, three-way catalysts, and an HC adsorbent arranged in the bypass exhaust passage for adsorbing hydrocarbons in exhaust gases and fully desorbing the adsorbed hydrocarbons when it is heated to a full desorption temperature or higher. A troidal passage of the main exhaust passage completely surrounds a portion of the bypass exhaust passage in which the HC adsorbent is arranged. A ratio S1/S2 of the cross-sectional area S2 of the troidal passage to the cross-sectional area of a flow-in passage is set in a range from 1.

Abstract: A fuel injection control system for an internal combustion engine comprises an ECU which calculates a direct supply ratio and a carry-off ratio, and detects a predetermined operating condition of the engine in which an increased amount of fuel is to be supplied to the engine. When the predetermined operating condition is detected, a plurality of fuel injection amounts to be sequentially injected by at least one fuel injection valve are calculated based on operating conditions of the engine, the direct supply ratio and the carry-off ratio. Then, an amount of fuel adhering to the intake system of the engine is calculated based on the total sum of the calculated plurality of fuel injection amounts, as well as on the calculated direct supply ratio and the calculated carry-off ratio. At least one of the calculated plurality of fuel injection amounts is corrected based on the calculated amount of fuel adhering to the intake system.

Abstract: An electromagnetically driven valve control system for an internal combustion engine having at least one intake valve and at least one exhaust valve, and a starter for starting cranking of the engine. A CPU controls an energization time/timing control circuit section to electromagnetically drive at least one of the at least one intake valve and the at least one exhaust valve. The CPU detects a starting signal indicative of starting of the cranking of the engine, and a timer measures a time period elapsed after the starting signal is detected. An inhibiting time period is set, over which the operation of the starter means is inhibited, and the at least one of the at least one intake valve and the at least one exhaust valve is driven in a valve closing direction when the starting signal is detected. The operation of the starter is permitted when the time period elapsed after the starting signal is detected exceeds the inhibiting time period.

Abstract: A system for detecting air-fuel ratio of an internal combustion engine by sampling outputs of an air-fuel ratio sensor installed at an exhaust system confluence point of said engine. A timing map is prepared to be retrieved by the engine speed and manifold absolute pressure to determine one among sampled data which are successively stored in buffers. It is selected such that as the engine speed decreases or the manifold absolute pressure increases, a datum sampled at earlier crank angular position is selected. At an engine equipped with a variable valve timing mechanism, a datum sampled at earlier crank angular position is selected in the valve timing is controlled for high engine speed provided that the engine speed and manifold absolute pressure is constant. The sampled data stored in the buffers may be transferred to another buffers at a predetermined crank angular position. The sampled data is corrected by an environmental conditions including atmospheric pressure, a mixture or sensor degradation.

Abstract: An air-fuel ratio control system for an internal combustion engine having first and second catalytic converters arranged in the exhaust passage comprises first to third exhaust gas component concentration sensors arranged in the exhaust passage, the first one being arranged upstream of the first catalytic converter, the second one at a location intermediate between the first and second catalytic converters, and the third one downstream of the second catalytic converter. An ECU carries out feedback control of the air-fuel ratio of a mixture supplied to the engine to a desired air-fuel ratio in response to an output from the first exhaust gas component concentration sensor. A first feedback control parameter for use in the feedback control is calculated, based on an output from the second exhaust gas component concentration sensor.

Abstract: A control system according to one aspect calculates a ratio of an actual amount of fuel supplied to the combustion chamber to the desired amount of fuel to be supplied to the combustion chamber, by taking into account at least an amount of evaporative fuel supplied to the combustion chamber, and sets the rate of change of the air-fuel ratio correction coefficient based on this ratio of the actual amount to the desired amount. A control system according to another aspect of the invention calculates an injected fuel ratio of an amount of fuel injected to an amount of total fuel to be supplied to the combustion chamber, and controls the ignition timing based on the injected fuel ratio and depending on operating conditions of the engine.

Abstract: A control system for an internal combustion engine according to one aspect of the invention calculates a total amount of evaporative fuel purged from a canister based on dynamic characteristics and concentration of purged gas. The system calculates an amount of evaporative fuel supplied to the combustion chamber of the engine based on the total amount of evaporative fuel and depending on dynamic characteristics of the purged gas. Then, the system determines a required amount of fuel to be injected by a fuel injection valve based on the amount of evaporative fuel supplied to the combustion chamber.

Abstract: A control system for controlling operation of an internal combustion engine detects a selected one of two exhaust modes: a first exhaust mode in which exhaust gases are guided through a first catalytic converter upstream of a second catalytic converter, and a second exhaust mode in which exhaust gases are guided through a bypass passage bypassing the first catalytic converter. A control mode is determined according to the selected one of the two exhaust modes, in which the operation of the engine is to be controlled by the control system.

Abstract: A control system for an internal combustion engine estimates an amount of adherent fuel adhering to the inner surface of the intake passage, as well as an amount of carried-off fuel evaporated form fuel adhering to the inner surface of the intake passage and carried into combustion chambers, determines an amount of supply fuel to be supplied to the engine, based upon operating conditions of the engine, the estimated adherent fuel amount, and the estimated carried-off fuel amount, and supplies the determined supply fuel amount into the intake passage. The control system calculates an amount of exhaust gases to be recirculated from the exhaust passage to the intake passage, and corrects the estimated adherent fuel amount and the estimated carried-off fuel amount, based upon the calculated exhaust gas recirculating amount, based upon the calculated exhaust gas recirculating amount.

Abstract: An air-fuel ratio control system for an internal combustion engine calculates an amount of fuel to be supplied to the engine in response to the rotational speed of the engine and a parameter indicative of load on the engine, and an amount of fuel injected into an intake passage and adhering to the inner surface of the intake passage, based upon a direct supply ratio and a carry-off ratio. A feedback correction value is set to such a value that an air-fuel ratio in exhaust gases from the engine becomes equal to a desired value, and the amount of fuel calculated as above is corrected by the direct supply ratio, the carry-off ratio, and the feedback correction value set as above. A control speed at which the feedback correction value is corrected is set based upon at least one of the direct supply ratio and the carry-off ratio.

Abstract: A control system for an internal combustion engine corrects an amount of supply fuel to the engine based upon operating conditions of the engine as well as an estimated amount of adherent fuel adhering to the inner surface of the intake passage and an estimated amount of fuel carried off fuel adhering to the intake passage inner surface and carried into combustion chambers. The correction of the supply fuel amount is limited when the engine is operating in an idling condition. According to a further aspect of the invention, the adherent fuel amount and the carried-off fuel amount are corrected based upon a calculated amount of exhaust gases and a detected operating mode or valve timing of at least one of intake valves and exhaust valves.