Abstract: A running state control system for a motor vehicle comprises engine output torque control means, shift detecting means, and a valve timing control system (VTC). When detecting a shifting, the shift detecting means outputs a torque cutoff command signal to the engine output torque control means so as to actuate the valve timing control system. An opening timing of intake valves is changed thereby in a direction such to decrease an engine output torque. In another aspect of the invention control is exercised over a braking torque applied to the driving wheels of the vehicle in correspondence with a traction loss or skid detected thereat.

Abstract: A variable cam engine with a valve driven by cams which rotate in synchronism with the engine revolution comprises a power cam which provide large torque, an economy cam which provides good fuel cost performance, a setting device to set a cam change-over region according to an engine running condition, and a cam change-over mechanism which changes over from one cam to another at the set change-over regions and transmits the motion of the cam selected by the change-over to the valve. It further comprises a device to correct the throttle opening such that the torque generated before and after making a cam change-over is the same. It may further comprise a device to retard the engine ignition period at the same time as the throttle opening is corrected when the cam change-over is made. This arrangement prevents the occurrence of a torque step when a change-over is made from the power cam to the economy cam and vice versa, and prevents shock or impairment of exhaust gas composition due to the cam change-over.

Abstract: An idle engine speed control apparatus for a multiple cylinder and multiple throttle valve engine includes a bypass passage and an idle control valve connected to each cylinder for controlling idle engine speed. Idle engine speed at a combustion stroke of each cylinder is calculated by a control unit and adjusted to a target engine speed by feedback-controlling each idle control valve according to a signal from the control unit. Furthermore, each throttle valve and idle control valve are disposed in the vicinity of each cylinder to quickly control the engine speed in each cylinder.

Abstract: This invention concerns a variable cam engine wherein cam change-over is performed according to the running condition of the engine. The engine is provided with a throttle valve whose opening basically corresponds to the accelerator depression, but which nevertheless can be freely varied irrespective of the accelerator depression. When a change-over is performed between the economy cam and power cams, a target throttle opening is computed such that the torque generated after the change-over is the same as the torque before the change-over. At the time, to prevent the occurrence of torque shock, the throttle valve is made to temporally overshoot the target opening, and then return to the target opening. The amount of this overshoot and the return time constant is computed based on at least the difference of throttle openings before and after change-over and the engine speed.

Abstract: A system and method for self diagnosing an engine controlling system such as an ignition system, fuel injection system, and an EGR (Exhaust Gas Recirculation) system are disclosed in which a periodic pseudo random signal is superposed on a control signal such as an ignition signal, fuel injection signal, or EGR rate controlled value indicating signal during an engine steady state condition, a cross-correlation function is calculated from both the superposed periodic random signal and output signal related to deterioration of the engine controlling system, and a value related to the cross-correlation function is compared with a reference value over which a performance of the engine controlling system cannot be maintained. If the value related to the cross-correlation function exceeds the reference value, the diagnostic system determines the occurrence of deterioration in the engine controlling system.

Abstract: Disclosed herein is a fuel supply control system for an internal combustion engine. The system comprises a fuel supply member for supplying fuel to each cylinder of the engine; a pressure sensor which outputs a signal representative of an internal pressure of each cylinder under compression stroke; a crankangle sensor which outputs two types of signals, one being a signal which is issued each time a crankshaft of the engine rotates by a given angle, and the other being a signal which is issued each time the crankshaft comes to a given angular position; a pre-ignition judging device for judging whether a pre-ignition occurs or not in each cylinder based on the signals from the pressure sensor and the crankangle sensor; and a fuel supply stop device for stopping the fuel supply to a cylinder when the pre-ignition judging device judges that the cylinder encounters the pre-ignition.

Abstract: A system and method for controlling an air/fuel mixture for an internal combustion engine are disclosed in which an integration constant used for a calculation of an integration portion included in a feedback correction coefficient (.alpha.) of the air/fuel mixture ratio after a relationship between an actual air/fuel mixture raito and target (stoichiometric) air/fuel mixture ratio has been inverted is set and varied according to an engine driving condition, so that the integration constant meets requirements of a stability during an engine steady driving condition and a favorable responsive characteristic during an engine transient condition. In a preferred embodiement, a fuzzy control is applicable to the calculation of the integration constant.

Abstract: A system for detecting and controlling an engine knocking the determination of occurrence of knocking is based on a present data on the detected pressure vibration energy in a combustion chamber of the engine and a value associated with a previous data on the detected pressure vibration energy in the combustion chamber so that an accurate detection of engine knocking can always be achieved. Furthermore, the knocking can be discriminated from the background noise even when the engine revolution speed is high.

Abstract: A guide sleeve is joined at an end thereof to the outer periphery of an annular pressure sensor and fits in an ignition plug accommodation hole. The pressure sensor is clamped between an ignition plug and a plug seating at the bottom of the ignition plug accommodation hole. The guide sleeve projects at the other end thereof from the ignition plug accommodation hole and mounts at the other end thereof an annular sealing member which has opposite axial ends brought into sealing contact with a cylinder head and a protective boot fitted on the ignition plug.

Abstract: A back-up system for an engine coolant temperature sensor detects deviation of the output of the temperature sensor from its designed output range to produce a fault signal. In response to the fault signal, an engine control system derives the engine coolant temperature indirectly from other engine conditions. This derivation is based on two facts: (1) the amount of fuel required to start the engine is related to engine temperature, and (2) since the calorific value of a given engine is essentially constant, the rate of increase of engine temperature is related to the integrated number of engine revolutions. Thus, when the engine is to be started, engine temperature can be derived by gradually increasing the fuel supply quantity from a minimal initial value until the engine is able to start to determine the required fuel supply quantity. Thereafter, the derived temperature value can be updated as a function of total engine revolutions.

Abstract: An air/fuel ratio control system is applicable to lean mixture combustion internal combustion engines. The control system determines the value of the mixture ratio at which engine stability can switch between stable and unstable conditions. As long as the engine continues to run in a stable condition in which the engine roughness is within an acceptable range, the mixture is intermittently leaned out by a given proportion. On the other hand, when engine roughness in an unacceptable range is detected, the mixture ratio is enriched by a given proportion to overcome the unacceptable engine roughness. Enrichment of the mixture is continued until engine roughness within the acceptable range is detected.

Abstract: An air fuel ratio control system includes a correction system for correcting air/fuel ratio depending on measured atmospheric air pressure. The correction system has sensors for detecting engine operating conditions. A reference intake manifold pressure corresponding to the detected engine operating condition at sea level is obtained from the engine operating condition. The reference atmospheric air pressure is compared with the measure intake manifold absolute pressure to determine a difference value. Based on the difference, a correction value for controlling the air/fuel ratio is determined.

Abstract: An engine control system is disclosed which employs first and second load sensors providing an inference of engine load by measuring first and second engine operating parameters. The system controls one or more engine operating functions based on a measurement on the first engine operating parameter but on a measurement on the second engine operating parameter when the change of the measurement of the first engine operating parameter is out of a predetermined range.

Abstract: Normally, an air-fuel ratio is controlled in accordance with the engine speed and the intake air quantity of an internal combustion engine with a turbocharger. When the output pressure of the turbocharger increases excessively, an intake relief valve opens to decrease the intake air quantity. In this case, the fuel injection quantity is controlled solely in accordance with the engine speed.

Abstract: In a method of supplying fuel to an internal combustion engine during start-up, the occurence of combustion is detected to arrest the change of the fuel supply quantity until steady-state engine operation is achieved. Combustion is detected by comparing sensed engine speed to a minimum engine speed resulting from combustion in the cylinders. Additionally, control values used to derive the start-up fuel quantity are modified so that the fuel quantity increases monotonically from a relatively low initial value until fuel ignition is detected.

Abstract: A throttle-valve most closed position sensing system is disclosed for use with an internal combustion engine. The system includes a throttle position sensor for providing a signal indicative of the degree of opening of the associated throttle-valve. A decision circuit is provided for deciding throttle-valve position as the most closed position when receiving a throttle-valve position indicative signal smaller than or equal to the smallest signal having received from the throttle position sensor.