Abstract: A basic knock detecting period is set based on engine speed and engine load. The basic knock detecting period is corrected with a learning correcting quantity in accordance with engine operating conditions, and a knock detecting period is determined based on the corrected knock detecting period. Knock is detected within the knock detecting period.

Abstract: An apparatus for controlling an air conditioning unit for an automotive vehicle includes an air conditioner switch for operating a compressor, engine speed detecting means, engine speed variation rate calculating means, engine speed reducing state determining means, and means for controlling the compressor to hold in an inoperative state even when the air conditioner switch is in a close state.

Abstract: An ignition timing controlling system is provided for calculating an ignition timing based on a basic ignition timing, a learning correcting quantity including a large correcting quantity and a small correcting quantity, and a feedback correcting quantity. In response to an occurrence of knocking, a large retard value is produced. When the large retard value exceeds a reference value, the learning correcting quantity of the small correcting quantity is changed to the learning correcting quantity of the large correcting quantity.

Abstract: An ignition timing controlling system is provided for calculating an ignition timing based on a basic ignition timing, a learning correcting quantity including a large correcting quantity and a small correcting quantity. A temporary correcting quantity having a small value is stored in a memory at starting of the engine, and increased in an advance direction until knocking of the engine occurs. The increased temporary correcting quantity is compared with the large correcting quantity and either of the quantities is selected as a proper correcting quantity. An ignition timing is calculated based on the selected quantity.

Abstract: An idle speed control apparatus of an engine, having a valve for changing an intake air quality to the engine, a device for measuring an engine coolant temperature, a circuit for detecting an engine speed, and a device responsive to said engine speed for controlling an opening degree of said valve to maintain said engine speed to a predetermined speed under idling state, comprising: a device for producing a signal when said engine coolant temperature exceeds a predetermined temperature; a device responsive to said signal for starting to count a cumulative time period; a device responsive to said cumulative time period for setting a correction opening degree; and a device responsive to said correction opening degree and a current opening degree of said valve means for calculating a learnt opening degree.

Abstract: An ignition controlling system has a first memory storing a plurality of upper limit ignition timings and lower limit ignition timings each of which is a maximum advance timing for high-octane gasoline and low-octane gasoline without causing knocking, and storing a plurality of maximum advance ignition timings. A second memory stores a coefficient for determining a dividing point between said upper and lower limit ignition timings. The coefficient is rewritten in accordance with occurrence of the knocking of the engine. A learning ignition timing is calculated from the upper and lower limit ignition timings and the coefficient derived from the first and second memory.

Abstract: An ignition controlling system has a memory storing a plurality of basic ignition timings each of which is a maximum timing for producing maximum torque with low-octane gasoline without causing knocking, and storing a plurality of maximum advance quantities. A learning control system has a memory storing a plurality of learning correcting quantities and rewriting the learning correcting quantity in accordance with occurrence of knocking of the engine. A basic ignition timing, a maximum advance quantity and a learning correcting quantity are derived from the memories in accordance with engine operating conditions. The learning correcting quantity is compared with the maximum advance quantity and smaller one is selected. The smaller quantity is added to the basic ignition timing to obtain an ignition timing.

Abstract: A plurality of reference pressures for pressure in an intake passage of the engine is stored in a memory so as to be derived in accordance with speed of the engine and opening degree of a throttle valve of the engine. A reference pressure is derived from the memory in accordance with the engine speed and the corrected opening degree. The pressure in an intake pipe is compared with the reference pressure. A fail-safe signal is generated when the intake pipe pressure is higher than the reference pressure. In response to the fail-safe signal, the fuel supply for the engine is cut off when the engine speed is higher than a predetermined speed.

Abstract: A plurality of reference pressures for pressures in an intake passage of the engine are stored in a memory so as to be derived in accordance with speed of the engine and opening degree of a throttle valve of the engine. A reference pressure is derived from the memory in accordance with the engine speed and the corrected opening degree. The reference pressure is delayed. Pressure in an intake pipe is compared with the delayed reference pressure. An abnormality signal is generated when the intake pipe pressure is higher than the delayed reference pressure.

Abstract: An automotive engine has a bypass around a throttle valve and at least one valve provided in the bypass. A plurality of reference pressures for pressures in an intake passage of the engine are stored in a memory so as to be derived in accordance with speed of the engine and opening degree of a throttle valve of the engine. Opening degree detected by a throttle position sensor is corrected with opening degree of the valve in the bypass to produce a corrected opening degree. A reference pressure is derived from the memory in accordance with the engine speed and the corrected opening degree. Pressure in an intake pipe is compared with the reference pressure derived from the memory. An abnormality signal is generated when the intake pipe pressure is higher than the reference pressure.

Abstract: A control method for the idling speed of an engine, in which method, from the engine speed at the time when transition toward the idling state is determined by the switching, for example, of an idling switch to "ON", the correction quantity of the control value of valve means for regulating the intake air quantity of the engine is set, a drop in the engine speed being avoided, and at the same time, in the convergence toward a learned value thereafter, convergence to the learned value of the valve means at a variation rate corresponding to the engine speed is made possible, whereby rapid correspondence toward feedback control is realized.