Abstract: An exhaust gas purifying apparatus for an internal combustion engine including a first filter and a second filter. The first filter traps particulates in exhaust gases from said engine. The second filter is provided for failure detection and disposed downstream of the first filter. The trapping state of the second filter is detected and a filtering capability of the first filter is diagnosed based on the detect trapping state of the first filter.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine, having a filter for trapping particulates in exhaust gases from the engine, is disclosed. A first particulate amount indicates an amount of particulates to be trapped by the filter and is calculated according to an operating condition of the engine. A second particulate amount indicates an amount of particulates trapped by the filter and is calculated according to a temperature of the filter when a filter regeneration of burning the particulates trapped by the filter is performed. The first particulate amount is compared with the second particulate amount, and a failure determination of the filter is performed according to a result of the comparison.

Abstract: An exhaust gas purifying apparatus for an internal combustion engine including a first filter and a second filter. The first filter traps particulates in exhaust gases from said engine. The second filter is provided for failure detection and disposed downstream of the first filter. The trapping state of the second filter is detected and a filtering capability of the first filter is diagnosed based on the detect trapping state of the first filter.

Abstract: In a system for controlling opening of a throttle valve installed at an air intake system of an internal combustion engine mounted on a vehicle, a fully-closed value of the opening of a throttle valve is learning-controlled based on a detected opening of the throttle valve to update the learned fully-closed value, when operating state of the vehicle is under a prescribed operating state such as the operator rides the accelerator pedal; and the updating of the learned fully-closed value is inhibited in valve opening direction until the operating state of the vehicle moves outside the prescribed operating state and then again returns to the operating state. In addition, an amount for updating in the opening direction is set smaller than that in the closing direction. With this, it becomes possible to avoid engine speed destabilization and other various problems even if the learned value in effect during pedal riding is used for engine idling speed control.

Abstract: In a system for controlling opening of a throttle valve installed at an air intake system of an internal combustion engine mounted on a vehicle, a fully-closed value of the opening of a throttle valve is learning-controlled based on a detected opening of the throttle valve to update the learned fully-closed value, when operating state of the vehicle is under a prescribed operating state such as the operator rides the accelerator pedal; and the updating of the learned fully-closed value is inhibited in valve opening direction until the operating state of the vehicle moves outside the prescribed operating state and then again returns to the operating state. In addition, an amount for updating in the opening direction is set smaller than that in the closing direction. With this, it becomes possible to avoid engine speed destabilization and other various problems even if the learned value in effect during pedal riding is used for engine idling speed control.

Abstract: A diagnostic apparatus for a vehicle can display diagnostic results and an indication of whether or not the diagnosis has been completed with a single display device. The diagnostic apparatus adapted to be mounted on the vehicle for diagnosing the vehicle based on driving condition parameters of the vehicle includes a display device or an indicator for indicating presence or absence of malfunction based on the diagnostic results, means for switching the diagnostic apparatus into a notification mode in response to a predetermined operation state, and a display control unit for displaying on the display device the indication of whether or not the diagnosis has been completed in response to being switched into the notification mode. The indication of whether or not the diagnosis has been uncompleted can be displayed on the display device by switching into a notification mode in response to the predetermined operation status.

Abstract: A diagnostic apparatus for a vehicle can display diagnostic results and an indication of whether or not the diagnosis has been completed with a single display device. The diagnostic apparatus adapted to be mounted on the vehicle for diagnosing the vehicle based on driving condition parameters of the vehicle includes a display device or an indicator for indicating presence or absence of malfunction based on the diagnostic results, means for switching the diagnostic apparatus into a notification mode in response to a predetermined operation state, and a display control unit for displaying on the display device the indication of whether or not the diagnosis has been completed in response to being switched into the notification mode. The indication of whether or not the diagnosis has been uncompleted can be displayed on the display device by switching into a notification mode in response to the predetermined operation status.

Abstract: A system for detecting malfunction of a radiator, more precisely a thermostat (shut-off valve) in the engine cooling system. In the system, an estimated coolant temperature CTW is calculated from the temperature condition and operating condition at engine starting. When the estimated coolant temperature CTW has reached a judge malfunction value CTWJUD but the detected coolant temperature TW has not reached a judge normal value TWJUD, the thermostat 64 is discriminated to have malfunctioned, thereby enabling to detect malfunction of the radiator with high accuracy and high response.

Abstract: When fully closed throttle opening learning device M1 learns a fully closed throttle opening value THMIN on the basis of an actual throttle opening value TH at an idle running time, comparison device M2 compares the sum of the fully closed throttle opening value THMIN and a predetermined value a with the actual throttle opening value TH to decide the possibility of the occurrence of a fault, and fault decision acceptance device M3 decides the acceptance/rejection of execution of the fault decision of an idle revolution controlling unit IC on the basis of the comparison result of the comparison device M2. As a result, even with a degradation in the output characteristics of a throttle opening sensor, an erroneous decision can be avoided by rejecting the execution of the fault decision when there is a possibility of an erroneous decision.

Abstract: A system for preventing overheating of an engine for a vehicle includes a revolution rate detector for detecting the rate of revolution of the engine carried on the vehicle, a device for reducing an engine power output in response to a value detected in the revolution rate detector exceeding a preset revolution rate, a device for predicting overheating of the engine, and a preset revolution rate correcting device for reducing the preset revolution rate in accordance with a reduction of the vehicle velocity in reply to prediction of an engine overheat condition by the overheat predicting device. An overheating due to an engine racing condition during vehicle travelling is prevented in view of an engine cooling effect provided by flowing air.

Abstract: A method for detecting an irregularity in the valve-timing changeover in an engine having a valve operating mechanism capable of operating the intake valves or exhaust valves, or both, in a different manner, known as valve timing, such as the magnitude of valve lift or the duration the valve remains open, for improving the operation of the engine at different engine speeds. The method compares the oil pressure in the supply passage to the valve timing changeover mechanism with the oil pressure that should exist after the changeover caused by the latest instruction to determine an irregularity if the pressures are not equal. A time delay may be used to accommodate the inherent time lay in the changeover to avoid a premature determination of an irregularity. An alarm may be energized or a fail-safe procedure initiated when an irregularity is detected.

Abstract: An intake air flow control apparatus for an internal-combustion engine, which includes a valve lift characteristic control means for variable control of the lift characteristics of intake and exhaust valves for the internal-combustion engine and a deceleration intake control means for controlling the quantity of intake air to be supplied to the downstream side of the intake throttle valve during the deceleration operation of the engine, comprises an intake control characteristic change means for changing the control characteristics of the deceleration intake control means in response to the valve lift characteristic control.

Abstract: A knocking control system for an internal combustion engine with inlet valves and exhaust valves having valve timing thereof controlled depending on operating conditions of the engine. It is determined whether or not knocking has occurred in the engine on the basis of a detection parameter indicative of knocking and at least one discrimination parameter. The operation of the engine is controlled by the use of at least one control parameter in response to the determination result, so as to eleminate knocking. The values of the discrimination and control parameters are selected in accordance with the actual valve timing. When abnormality in the valve timing control is detected, the valve timing is held at predetermined valve timing irrespective of engine operating conditions, and values of the at least one discriminating parameter and the at least one control parameter are selected, which correspond to the held predetermined valve timing.

Abstract: A knocking control system for an internal combustion engine with the inlet valves and exhaust valves having valve timing thereof controlled depending on operating conditions of the engine. It is determined whether or not knocking has occurred in the engine on the basis of a detection parameter indicative of knocking and at least one discrimination parameter. The operation of the engine is controlled by the use of at least one control parameter in response to the determination result. The values of the discrimination and control parameters arfe selected in accordance with the actual valve timing. The detection parameter is a level of vibration of the engine comprising a noise component and a knocking component. It is determined that knocking has occurred when the level of the knocking component is higher than one knocking discrimination level set based on the level of the noise component and the discrimination parameter irrespective of the actual valve timing.

Abstract: A method of controlling the air-fuel ratio of a mixture of fuel supplied to an internal combustion engine. Feedback control is effected to response to an output from an exhaust-gas concentration sensor to bring the air-fuel ratio to a predetermined value when the engine is in a predetermined medium-load operating region. It is determined whether or not the engine is in a predetermined high-load operating region in which the feedback control is interrupted for bringing the air-fuel ratio to a value smaller than the predetermined value, and whether or not the engine is in a predetermined low-load operating region in which the feedback control is interrupted for bringing the air-fuel ratio to a value larger than the predetermined value.

Abstract: A method of controlling the supply of fuel to an internal combustion engine having first and second fuel injection valves arranged in the intake passage downstream and upstream of the throttle valve, respectively, both being upstream of the intake manifold wherein the first and second fuel injection valves are selectively operated to supply fuel to the cylinders in dependence on operating conditions of the engine. Fuel is supplied to a plurality of cylinders of the engine through the first fuel injection valve alone when the engine is operating in a predetermined low load condition. In a middle/high load middle speed region of the engine, a substantially constant minimum required quantity of fuel is supplied through the first fuel injection valve, and simultaneously a quantity of fuel appropriate to the middle/high load middle speed region is supplied through the second fuel injection valve.

Abstract: A fuel supply control system for an internal combustion engine having a fuel injection valve arranged within a suction passage at a location upstream of an intake manifold and a throttle valve therein, and an air throttle valve arranged within the suction passage at a location upstream of the throttle valve and having a throttle opening disposed to be positioned opposite the nozzle of the fuel injection valve when the air throttle valve is fully closed whereby intake air flows through the throttle opening in the vicinity of the nozzle of the fuel injection valve at an increased speed. The system controls a quantity of fuel supplied to a plurality of cylinders of the engine in accordance with operating conditions of the engine. Further, the system increases the quantity of fuel when the air throttle valve is opened.

Abstract: A method of controlling the quantity of fuel supplied to an internal combustion engine after starting thereof. An initial value of a fuel increment is set in response to a temperature of the engine immediately after the start of the engine, and is subsequently decreased with the lapse of time. A quantity of fuel set by the use of the thus decreased fuel increment is supplied to the engine. The rate of decrease of the fuel increment is set to a value corresponding to a sensed temperature representative of fuel injection valves of the engine. Preferably, the rate of decrease is set to a smaller value when the sensed temperature is equal to or higher than a value corresponding to the boiling point of the fuel, than a value set when the former is lower than the latter.

Abstract: A method of controlling the fuel supply to an internal combustion engine in response to operating conditions thereof. First and second groups of basic fuel quantity values are set beforehand as a function of a first engine operation parameter including at least the engine rotational speed, the basic fuel quantity values of the second group being each larger than a corresponding one of those of the first group for the same first engine operation parameter value. When it is determined from a detected second engine operation parameter value indicative of engine load that the engine is operating in a predetermined high load condition, one basic fuel quantity value of the second group is selected that corresponds to a detected first engine operation parameter value, and corrected by a fuel increment based upon a detected engine temperature value and the detected second engine operation parameter value. A fuel quantity is set on the basis of the corrected one basic fuel quantity and supplied to the engine.

Abstract: A method of controlling the operating amount of a control valve for regulating the quantity of supplementary air being supplied to an internal combustion engine, in a feedback manner responsive to the difference between a desired idling speed and an actual engine speed, while the engine is in a predetermined idling region. When the engine is in a predetermined decelerating region immediately preceding the predetermined idling region, a basic value of the operating amount of the control valve is corrected in dependence upon a detected value of the engine temperature and a detected value of the decreasing rate of the engine speed. When the engine is further decelerated into the predetermined idling region, the feedback control is started by applying the corrected basic value of the operating amount of the control valve as an initial value thereof.