Abstract: Exhaust gas cleaner system for an automotive internal combustion engine includes an air introduction pipe 8 for introducing secondary air, heated initially by a heater 23, to the catalytic converter unit 7 mounted on the exhaust pipe 3. The ignition timings of the engine is retarded at least during the time when the secondary air is heated by the heater 23. Preferably, the number of ignition timings are counted by a counter modulo 5, for example, in the case of a four-cylinder engine, and the ignition timings are retarded when the counter content is 3 or 4, such that the ignition timings of the cylinders are retarded intermittently. Alternatively, the retardation of the ignition timings may be terminated before the introduction of the heated secondary air is terminated.Where two first and second catalytic converter units 7a and 7b are provided, secondary air distributed by a change-over valve 10a is heated separately by heaters 23b and 23c.

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: 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 exhaust gas recirculation control system includes a stepping motor driven valve for controlling the flow rate of exhaust gas through a recirculation pipe of an internal combustion engine, and arithmetic circuitry for calculating the exhaust gas recirculation flow rate in dependence on the operating state of the engine. A two-phase excitation driving scheme and a one/two-phase excitation driving scheme are exchangeably adopted for driving the stepping motor to control the opening of the recirculation control valve. When a rapid response is required, the two-phase excitation driving scheme is put into effect, with the one/two-phase excitation driving scheme being adopted when high resolution is required.

Abstract: A flow quantity valve controller includes a unit for positioning so that a phase of a stepper motor becomes a predetermined phase when a motor shaft making a linear move with rotation of the stepper motor is pulled most into the stepper motor side. When the motor shaft is pulled most into the stepper motor side, a flow quantity valve controller changes a stepper motor drive signal to a drive signal corresponding to a predetermined phase.

Abstract: A fault detecting apparatus for an exhaust gas recirculation control system of an internal combustion engine includes a throttle valve provided in an intake pipe of the engine, an exhaust gas recirculation pipe for introducing an exhaust gas of the engine to the intake pipe downstream of the throttle valve, an exhaust gas recirculation valve for regulating a recirculation flow rate of the exhaust gas, sensors for detecting operation state inclusive of an intake pressure, an exhaust gas recirculation valve control unit for controlling the exhaust gas recirculation valve in accordance with operation state information, a fault decision enabling condition detecting means for detecting satisfaction of the condition enabling the decision about occurrence of fault in the recirculation valve control unit on the basis of the operation state information, a unit for forcibly opening and/or closing the exhaust gas recirculation valve when the fault decision enabling condition is satisfied, a fault decision means for comp

Abstract: Exhaust gas cleaner system for an automotive internal combustion engine includes an air introduction pipe 8 for introducing secondary air, heated initially by a heater 23, to the catalytic converter unit 7 mounted on the exhaust pipe 3. The ignition timings of the engine is retarded at least during the time when the secondary air is heated by the heater 23. Preferably, the number of ignition timings are counted by a counter modulo 5, for example, in the case of a four-cylinder engine, and the ignition timings are retarded when the counter content is 3 or 4, such that the ignition timings of the cylinders are retarded intermittently. Alternatively, the retardation of the ignition timings may be terminated before the introduction of the heated secondary air is terminated.Where two first and second catalytic converter units 7a and 7b are provided, secondary air distributed by a change-over valve 10a is heated separately by heaters 23b and 23c.

Abstract: A dual-sensor type air-fuel ratio control system for an internal combustion engine. A catalytic converter is disposed within an exhaust pipe for purifying an exhaust gas. A first air-fuel ratio sensor 11 is disposed upstream of the catalyst for detecting concentration of a particular component of the exhaust gas to output a first air-fuel ratio signal V1 indicating the concentration. A second air-fuel ratio sensor 12 is disposed downstream of the catalyst for detecting concentration of the particular exhaust gas component to output a second air-fuel ratio signal V2 indicating the concentration. An electronic control unit M8 controls a target air-fuel ratio of a mixture supplied to the engine by arithmetically determining an air-fuel ratio control quantity on the basis of the first and second air-fuel ratio signals.

Abstract: A dual-sensor type air-fuel ratio control system for an internal combustion engine. A catalytic converter is disposed within an exhaust pipe for purifying an exhaust gas. A first air-fuel ratio sensor 11 is disposed upstream of the catalyst for detecting concentration of a particular component of the exhaust gas to output a first air-fuel ratio signal V1 indicating the concentration. A second air-fuel ratio sensor 12 is disposed downstream of the catalyst for detecting concentration of the particular exhaust gas component to output a second air-fuel ratio signal V2 indicating the concentration.

Abstract: A dual-sensor type air-fuel ratio control system for an internal combustion engine. A catalytic converter disposed within an exhaust pipe is flanked by first and second upstream and downstream air-fuel ratio sensors 11, 12. An apparatus for detecting deterioration of the catalytic converter includes a deterioration parameter calculating circuit 60, a filter circuit 61, and a comparison decision circuit 62. The decision circuit compares a filtered deterioration parameter value .gamma.f with a predetermined value corresponding to a detected operation state of the engine to determine deterioration of the catalyst when the deterioration parameter value exceeds the predetermined value.

Abstract: A device for detecting the deterioration of a catalyst wherein oxygen sensors are provided on the upstream and downstream sides of the catalytic converter. Circuitry is provided for calculating integration values corresponding to areas surrounded by output signals of the oxygen sensors and designated signals; for calculating time periods between which the sensor signals reverse polarity with respect to the designated signals; for calculating a parameter for determining deterioration of the catalyst based on the integration values, the time periods or a combination of both; for determining deterioration of the catalyst by comparing the calculated parameter with a predetermined value; and for issuing an alarm when the catalyst is determined as deteriorated.

Abstract: An air-fuel ratio sensor malfunction detecting apparatus detects the output signal periods of a first or upstream air-fuel ratio sensor, and compares them with a predetermined value to judge the first sensor to be malfunctioning when the periods are larger than the predetermined value. The apparatus also compares the magnitudes of air-fuel ratio control quantities from a second or downstream air-fuel ratio sensor with a predetermined value to judge the first sensor to be malfunctioning when the air-fuel ratio control quantities are larger than the predetermined value.

Abstract: A dual-sensor type air-fuel ratio control system for an internal combustion engine. A catalytic converter disposed within an exhaust pipe is flanked by first and second upstream and downstream air-fuel ratio sensors 11, 12. An apparatus for detecting deterioration of the catalytic converter includes a deterioration decision circuit 54 for determining deterioration of the catalyst on the basis of at least the second air-fuel ratio sensor signal, a filter circuit 50 for filtering the second sensor signal, and a comparison circuit 51 for comparing the second sensor filtered and unfiltered signals. The deterioration decision circuit compares a deterioration parameter value derived from the result of the comparison with a predetermined value corresponding to a detected operation state of the engine to determine deterioration of the catalyst when the deterioration parameter value exceeds the predetermined value.

Abstract: A malfunction sensing apparatus for a fuel vapor control system includes a fuel tank and a canister containing an adsorbent for adsorbing fuel vapor. The canister has an inlet connected to the fuel tank and an outlet. A purge control valve is connected to the outlet for connecting and disconnecting the outlet of the canister from the air intake pipe of an engine. A pressure sensor senses the internal pressure of the fuel tank. A malfunction sensing means responsive to the pressure sensor senses a malfunction when the purge control valve is open and the pressure sensed by the pressure sensor is above a prescribed value. A prohibiting means senses the rate of change and/or the magnitude of the pressure sensed by the pressure sensor with the purge control valve closed and prohibits malfunction sensing by the malfunction sensing means when the rate of change of the pressure exceeds a prescribed rate and/or the magnitude of the pressure exceeds a prescribed value.

Abstract: A troubleshooting system for an exhaust gas recirculation (EGR) controller, which troubleshoots the EGR controller in an optimal short EGR-OFF time by not only detecting either a rate of change of an intake manifold pressure or a difference between a maximum and a minimum thereof associated with the turning on and of the EGR in accordance with an EGR flow amount using an operation condition detecting means, but also detecting a number of revolutions of an engine or the like.

Abstract: A fault diagnosis device and process for an exhaust gas recycle control unit of an engine, comprising a return pipe for returning the exhaust gas to an intake pipe, apparatus for opening and closing the return pipe and apparatus for detecting and storing engine operating conditions when the return pipe is opened and closed. The opening and closing apparatus is controlled so that the flow rate of the returned gas is gradually changed when the return pipe is closed from the open state or vice versa.

Abstract: An internal combustion engine control device having an exhaust gas recycle system which has an exhaust gas recycle line to an air intake pipe, the engine control device comprises at least pressure detect means as one of driving condition detect means for detecting a pressure for calculating an exhaust gas flow rate while said exhaust gas is recycled. A trouble detect means is provided for detecting a trouble in the exhaust gas recycle system on the basis of the pressure value detected by the pressure detect means. An engine control means is provided for controlling the engine speed based on the detected driving conditions by the driving condition detect means and based on an atmospheric pressure calculated from the pressure value detected by the pressure detect member.

Abstract: A disorder diagnosis device for a combustion engine having a fuel injector for each cylinder and a fuel system for supplying fuel to the injector comprises an air-fuel ratio sensor provided at an exhaust tube of the combustion engine for providing an air-fuel ratio signal indicative of an air-fuel ratio, and a control unit responsive to the air-fuel ratio sensor for calculating a first value by comparing the air-fuel ratio signal with a preset value and for calculating a second value by comparing a signal corresponding to the air-fuel ratio signal with a predetermined value so as to decide if the fuel system is in disorder on the basis of a combination of the first and second values.

Abstract: A failure diagnosis device of an exhaust gas recirculation control device which comprises a recirculation pipe for recirculating the exhaust gas of the internal combustion engine to an intake air pipe; a recirculation valve for controlling a flow quantity of the exhaust gas flowing in the recirculation pipe; a recirculation valve passage area controlling means for controlling a passage area of the recirculation valve; a running condition detecting means for detecting a running condition of the internal combustion engine; a first detected value memorizing means for memorizing a first detected value which is detected by the running condition detecting means when the passage area of the recirculation valve is in a first state of being wide, by the recirculation valve passage area controlling means; a second detected value memorizing means for memorizing a second detected value which is detected by the running condition detecting means when the passage are of the recirculation valve is in a second state of being

Abstract: An exhaust gas recirculation control device adapted to control a recirculation of part of exhaust gas of an internal combustion engine back to the engine which comprises a recirculation pipe for recirculating the exhaust gas of the internal combustion engine back to an intake air pipe; a recirculation valve for controlling a flow quantity of the exhaust gas flowing in the recirculation pipe; a recirculation valve passage area controlling means for controlling a passage area of the recirculation valve; a running condition detecting means for detecting a running condition of the internal combustion engine; a pressure difference detecting means for detecting a pressure difference between pressures at two arbitrary points in the recirculation pipe from an exit of the recirculation valve to the intake air pipe or a pressure difference between pressures at two arbitrary points in the recirculation pipe from an inlet of the recirculation valve to an exhaust pipe; a first exhaust gas recirculation ratio calculating m