Abstract: The control system of the present invention is provided for a hybrid vehicle with an engine and a motor, which are power sources, and a power storage unit for storing energy generated by the output from the engine and regenerative energy produced by regeneration of the motor when the vehicle decelerates. Based on monitoring the state of charge of the power storage unit, when the stored energy is discharged so that the remaining charge is decreased from an initial state of charge, which was detected when the vehicle started running, by a predetermined amount, the function of the motor is switched from the discharging of the power storage unit to the charging of the power storage unit.

Abstract: A control system for a vehicle calculates a desired driving force required by the vehicle in response to operating conditions of the vehicle including an amount of operation of an accelerator pedal of the vehicle, and controls the driving force of the vehicle, based on the calculated desired driving force. The desired driving force is corrected depending on whether the vehicle is in a particular operating condition. For example, when the vehicle is in a standing condition while traveling on a road congested with traffic when the desired driving force is corrected in the decreasing direction, the correction amount of the desired driving force in the decreasing direction is corrected to a value closer to zero. The desired driving force is also corrected according to a time period over which the particular operating condition continues.

Abstract: An output torque control system for an internal combustion engine for a vehicle is operable during gear shifting of an automatic transmission of the engine, for changing the output torque of the engine so as to reduce a shock caused by the gear shifting. The timing of termination of the changing of the engine output torque is determined, based on a rate of change in the traveling speed of the vehicle. The changing of the engine output torque terminated at the determined timing of termination.

Abstract: A control system for an internal combustion engine for a vehicle. Upon starting of gear shifting of an automatic transmission of the engine, which increases the change gear ratio of the automatic transmission, the output torque of the engine is increased to reduce a shock generated during the gear shifting. Retrogression of the gear shifting in the inertia phase of the automatic transmission is detected, and when the retrogression is detected, the output torque of the engine is additionally increased. A control amount for additionally increasing the output torque of the engine is calculated, and the timing of termination of the additional increasing of the output torque of the engine is detected.

Abstract: An output torque control system for an internal combustion engine for a vehicle is operable during an upshift of an automatic transmission of the engine to increase the output torque from the engine, based on a control amount for increasing the output torque, to reduce a shock generated by the upshift. During the upshift of the automatic transmission, a slip amount of one of a plurality of clutches of the automatic transmission which is selected for the upshift is compared with a predetermined value. A calculation is made of a value of the control amount assumed when the slip amount of the one clutch becomes equal to the predetermined value, as a result of the comparison. The control amount is limited to the calculated value when the slip amount exceeds the predetermined value, as a result of the comparison.

Abstract: A control system for an internal combustion engine with an automatic transmission having a torque converter, and a lock-up device. When gear shifting of the automatic transmission is carried out, the output torque of the engine is increased so as to reduce a shock caused by the gear shifting. The engaging force of the lock-up device is changed in response to the increase of the output torque.

Abstract: A combustion state-detecting system for internal combustion engines has a crank angle sensor which generates a crank angle signal with a predetermined period shorter than the firing period of the engine whenever the crankshaft rotates through a predetermined angle. A value of the rotational speed of the engine is detected whenever the crank angle signal is generated. An average value of the detected engine rotational speed is calculated over every period of one rotation of the crankshaft. A difference amount between a newest value of the average value of the detected engine rotational speed and a value of the average value calculated a predetermined number of firing periods earlier is calculated. The combustion state of the engine is detected based on the difference amount.

Abstract: A combustion state-detecting system for an internal combustion engine comprises a rotational speed sensor for detecting a value of the rotational speed of the engine with a predetermined repetition period shorter than the firing period of the spark plug whenever the crankshaft rotates through a predetermined angle, and an ECU which calculates a difference amount between a value of the detected rotational speed of the engine and a value of the detected rotational speed of the engine a predetermined number of firing periods earlier. A combustion state of the engine is detected based on the calculated difference amount.

Abstract: A control system for an internal combustion engine for an automotive vehicle determines whether a catalytic converter arranged in the exhaust system of the engine is in a predetermined high temperature condition. When it is determined that the catalytic converter is in the predetermined high temperature condition, priority is given either to a decrease in the amount of intake air supplied to the engine or to an increase in the amount of fuel to be supplied to the engine, depending on operating conditions of the engine.

Abstract: A driving force-calculating system calculates a desired driving force required by an automotive vehicle depending on operating conditions of the vehicle. A kinetic energy parameter representative of kinetic energy of the vehicle is calculated from an amount of change in speed of the vehicle assumed during acceleration of the vehicle. A correction coefficient is calculated based on an average value of a maximal value of the kinetic energy parameter assumed within a predetermined time period. The desired driving force required by the vehicle is calculated by the use of the correction coefficient. A control system for automotive vehicles which incorporates the driving force-calculating system is also provided.

Abstract: A high probability of detecting an erroneous misfire occurs when combustion becomes unstable during jolt control. Therefore, during jolt control the reliability of the misfire detection system is degraded. As a result, the misfire detection system is inactivated during jolt control by discontinuing the misfire detection, or by deliberately deeming no misfire has occurred if jolt control has occurred. Alternatively, the misfire detection sensitivity is masked during jolt control.

Abstract: A combustion state-determining system for an internal combustion engine, includes an ECU which detects misfires occurring in the engine, calculates a rate of misfire occurrence every predetermined number of firing cycles, based on the detected misfires, and determines that the engine is in a misfiring state when the calculated rate of misfire occurrence exceeds a predetermined reference rate. Further, a temperature state of the engine is detected, and the predetermined reference rate is changed based on the detected temperature state.

Abstract: A combustion state-determining system for an internal combustion engine has an ECU which determines a misfiring state of the engine, and calculates a misfiring rate of the engine, based on the result of the determination of the misfiring state. A catalyst temperature sensor detects the temperature of a catalytic converter as the exhaust system temperature, and the ECU determines the combustion state of the engine, based on the detected exhaust system temperature and the calculated misfiring rate. A combustion state control system restrains the output from the engine, based on the determination result of the combustion state-determining system.

Abstract: A combustion state-detecting system for internal combustion engines has a crank angle sensor which generates a crank angle signal with a predetermined period shorter than a firing period of the engine whenever the crankshaft rotates through a predetermined angle. A value of the rotational speed of the engine is detected whenever the crank angle signal is generated. A first average value of the detected engine rotational speed is calculated over every period of one rotation of the crankshaft, followed by calculating a second average value of the first average value over every firing period, to thereby calculate a rate of variation in the second average value over every firing period. Values of the rate of variation are averaged over a predetermined number of ignition cycles of the engine, to obtain a third average value. A cumulative value of the absolute value of a difference between the third average value and the rate of variation is calculated over the above predetermined number of ignition cycles.

Abstract: A combustion state-determining system for an internal combustion engine, in which an ECU detects misfires occurring in the engine. A first counter counts the number of times of occurrence of misfires detected every predetermined number of firing cycles, and a second counter counts the number of times of occurrence of misfires detected every predetermined repetition period which is a predetermined integer times as long as the predetermined number of firing cycles. The count value of the first counter is compared with a first reference value and a second reference value smaller than the first reference value every predetermined number of firing cycles, to determine that the engine is in a combustion state adversely affecting at least one exhaust system component part when the former is larger than the latter.

Abstract: A combustion state-detecting system for an internal combustion engine is provided, which detects misfires occurring in the engine. A crank angle sensor generates a crank angle signal with a predetermined period shorter than a firing period of the engine whenever the crankshaft rotates through a predetermined angle. An ECU detects the rotational speed of the engine, based on the crank angle signal whenever the crank angle signal is generated to generate a rotational speed signal, and filters the rotational speed signal to extract a specific frequency component therefrom. A rate of variation in the extracted specific frequency component is calculated every first predetermined time period, and an average value of the rate of variation is calculated every second predetermined time period longer than the first predetermined time period.

Abstract: A method of detecting deterioration of a three-way catalyst of an internal combustion engine comprises the steps of (1) obtaining a first signal and a second signal based on respective signals outputted from a pre-catalyst O.sub.2 sensor and a post-catalyst O.sub.2 sensor at least one of when the fuel supply to the engine is increased and when the fuel supply to the engine is interrupted, (2) comparing a waveform of a signal outputted from the pre-catalyst O.sub.2 sensor with a waveform of a signal outputted from the post-catalyst O.sub.2 sensor, based on the first and second signals while the engine is in a predetermined stable operating condition, and (3) determining from results of the comparison whether or not the three-way catalyst is deteriorated.

Abstract: A combustion state-detecting system, for internal combustion engines, has a crank angle sensor. The crank angle sensor generates a crank angle signal with a predetermined period shorter than a firing period of the engine whenever the crankshaft rotates through a predetermined angle. A value of the rotational speed of the engine is detected whenever the crank angle signal is generated. A first average value of the detected engine rotational speed is calculated over a period of one rotation of the crankshaft, followed by calculating a second average value of the first average value over every firing period, to thereby calculate a rate of variation in the second average value over every firing period. The rate of variation is compared with a predetermined value, to determine whether or not the engine is in a degraded state of combustion.

Abstract: A combustion state-detecting system for internal combustion engines has a crank angle sensor which generates a crank angle signal with a predetermined period shorter than a firing period of the spark plug whenever the crankshaft rotates through a predetermined angle. A value of the rotational speed of the engine is detected whenever the crank angle signal is generated. A rate of variation in the detected value of the rotational speed of the engine is calculated over the firing period of the spark plug, and an average value thereof is then calculated. The calculated average value of the variation rate is compared with the calculated variation rate, and a cumulative value of a difference between the calculated variation rate average value and the calculated variation rate is calculated when the calculated variation rate is on the larger deceleration side of the engine rotational speed with respect to the calculated variation rate average value.

Abstract: A tank internal pressure-detecting device for an internal combustion engine having an evaporative emission control system for controlling purging of evaporative fuel generated in a fuel tank thereof into an intake system thereof. An ECU interrupts purging of evaporative fuel by the evaporative emission control system for a predetermined period of time after the engine is started. The ECU causes control valves of the evaporative emission control system to open the interior of the fuel tank to the atmosphere, and stores a value of pressure within the fuel tank detected by a tank internal pressure sensor as a reference value while the purging is being interrupted and at the same time the interior of the fuel tank is opened to the atmosphere. The ECU corrects an output value of the tank internal pressure sensor, based upon the reference value stored.