Abstract: An engine speed calculating apparatus capable of calculating an engine speed without being affected by pulsating revolutions in a low engine speed range. A time required for a crankshaft of an engine to revolve through a predetermined angle is measured upon each completion of revolution through the predetermined angle, and an engine speed is calculated on the basis of measured result data of the time required for revolution through the predetermined angle. When the preceding calculated engine speed is determined to be lower than a predetermined engine speed, an engine speed is calculated on the basis of a time required for the crankshaft to revolve through an angle larger than the predetermined angle.

Abstract: A stroke judgment device includes a gear having a portion with no teeth, a pulse generator, an intake pipe internal pressure detecting device and an ECU. The ECU controls an injector(s) and the ignition timing of a spark plug(s). The ECU mainly includes a phase detecting device for detecting the phase of the crankshaft, a first stroke judging device for judging stroke based on detected phase and intake pipe internal pressure, a rotational cycle detection device for detecting rotational cycle of the crankshaft, a comparison device for comparing two rotation cycles of specified phase, a second stroke judging device for judging stroke based on results of comparison, and selection device for selecting one of the first stroke judging device or the second stroke judging device.

Abstract: Calculating an acceleration corrective in response to a subtle change in a throttle action by utilizing first and second rate-of-change calculators to calculate rates of change D&thgr;THA, D&thgr;THB of a throttle opening in preceding first and second periods (second period > first period) per a predetermined crankshaft rotational angle). A maximum value updater updates a stored value in a maximum value memory with a greater one of past and present maximum rates of change D&thgr;TH of the throttle opening, based on a compared result from a comparator. Points in a plurality of cycles read from a point calculator based on the maximum rate of change D&thgr;TH of the throttle opening are added together and inputted to a corrective value calculator.

Abstract: To change a fuel injection quantity to follow a throttle opening change in a low load region. A first calculator calculates a basic injection time using a throttle opening and an engine rotational speed. A second calculator calculates a basic injection time using an intake pipe negative pressure and the engine rotational speed. A selector selects the first calculator when the load is higher, and selects the second calculator when the load is lower. If the rate of change of the throttle opening is greater than a reference value, then a switcher sets the selector to select the first calculator. Thus, if the rate of increase of the throttle opening is greater than the reference value even when the load is low, the first calculator is selected.

Abstract: To allow an engine having an intake duct for drawing running air to produce a high output by performing appropriate fuel injection depending on dynamic pressure variations. A vehicle speed corrective coefficient calculator calculates a fuel corrective coefficient KVPLS based on a vehicle speed VPLS, and a throttle corrective coefficient calculator calculates a corrective coefficient KV&thgr;TH based on a throttle opening &thgr;TH. A corrective coefficient multiplier multiplies the fuel corrective coefficient KVPLS and the corrective coefficient KV&thgr;TH, thus calculating a vehicle speed fuel adjustment corrective coefficient KVAF. An injection time calculator calculates a basic injection time TiM based on the throttle opening &thgr;TH and an engine rotational speed Ne, and also calculates a fuel injection time Ti by reading the vehicle speed fuel adjustment corrective coefficient KVAF and correcting the basic injection time TiM.

Abstract: To provide an engine speed calculation apparatus which can facilitate calculation processing of the engine speed without being influenced by pulsation rotation in a low speed region of an engine. In a low speed region of an engine, a predetermined value is divided by a time required for rotation over an angle equal to a plurality of times of a predetermined angle to calculate the engine speed, but in a high speed region of the engine in which pulsation occurs less likely, the predetermined value is divided by the value equal to the plurality of times of the time required for rotation over the predetermined angle to calculate the engine speed.

Abstract: The present invention provides a control apparatus for controlling an internal combustion engine that enables preferable acceleration in response to the running status of the internal combustion engine. When a computer which computes the fuel supply of the internal combustion engine at each engine cycle according to engine parameters detects a change in the throttle opening level of the internal combustion engine from a low opening level which is lower than a predetermined opening level to a non-low opening level which is higher than the predetermined level and when the computer detects that a variation &Dgr;&thgr;TH in the opening level of a throttle is equal to or greater than a predetermined value, the computer generates different increment correction values and corrects fuel supply according to the increment correction values.

Abstract: An ignition timing control device for an internal combustion engine is capable of preventing shock of an engine upon rapid acceleration by suitably controlling the ignition timing of the engine. When the width of the opening of a throttle valve is kept within a specific width for a first specific time or more in a state where the opening of the throttle valve is smaller than a specific low opening and immediately after, the opening of the throttle valve is increased from the specific low opening to more than a specific high opening for a second specific time or less, it is decided that the internal combustion engine is in a rapid acceleration state. Ignition timing of the engine is therefore retarded.

Abstract: Optimum control is performed in one cylinder of an internal combustion engine. By determining a desirable control operation stage for each cylinder in advance on the basis of engine parameters. Control operation is executed at the timing where the operation stage for each cylinder reaches the determined control operation stage.

Abstract: An ignition timing control method and apparatus for an internal combustion engine mounted on a motor vehicle can prevent the occurrence of the knocking in the internal combustion engine. When the engine is running within a specific speed range and the transmission gear ratio is high, the control device determines that the engine is running under a condition where knocking is likely to occur. Accordingly retarding of the ignition timing in the internal combustion engine is accomplished in order to prevent knocking.

Abstract: To provide a fuel injection control apparatus of a multicylinder internal combustion engine capable of adjusting the quantity of fuel injection between cylinders by use of the fewest possible number of rheostats. The quantity of fuel to be injected into each cylinder of an internal combustion engine is calculated. Any one of a plurality of cylinders in the multicylinder internal combustion engine is selectively designated in accordance with an output of a first variable control section. An adjusting data indicating the amount of adjustment for the fuel injection quantity is generated in accordance with the output of a second variable control section and the quantity of fuel injection is corrected in accordance with the adjustment data when the fuel injection quantity corresponding to one cylinder designated in the mode of fuel adjustment between cylinders is calculated, so that only the corrected quantity of fuel injection will be injected to one cylinder thus designated.

Abstract: An oxygen concentration sensor trouble discriminating apparatus in which a counter executes a counting operation every time a lean state of an air-fuel ratio is detected on the basis of an output signal of an oxygen concentration sensor for the first time after a feedback control operating state was not detected. In the case where the air-fuel ratio feedback control operating state is detected, if the output signal of the oxygen concentration sensor indicates an inversion of the rich and lean states of the air-fuel ratio, a count value of the counter is reset to an initial value. When the count value is larger than a predetermined value, the oxygen concentration sensor is decided to be in trouble.

Abstract: A combustion control apparatus for a spark ignition type 2-cycle internal combustion engine includes fresh air mixed with fuel in a combustion chamber which can be self-ignited at an ignition timing preferable for the operation of the internal combustion engine at least in a low load operation region to effect active thermal atmosphere combustion. When it becomes necessary to stop the internal combustion engine quickly, upon starting of the internal combustion engine again, the starting performance is high. A combustion control apparatus for a spark ignition type 2-cycle internal combustion engine includes fresh air mixed with fuel in a combustion chamber which can be self-ignited at least in a low load operation region.

Abstract: In a key switch system for a vehicle, a plurality of tumblers 6 and a pair of cylinder pins engaging tumbler engagement grooves 1.sub.2 in an outer cylinder 1 are radially slidably carried in an inner cylinder 2 which is rotatably carried within the outer cylinder 1. If a key K is correctly and deeply inserted into a key hole 2.sub.1, the tumblers 6 are disengaged from the tumbler engagement grooves 1.sub.2 by a code valley K.sub.1 of the key K, and the pair of cylinder pins 8 are disengaged from the tumbler engagement grooves 1.sub.2 by a tip end K.sub.2 of the key K, thereby permitting the rotation of the inner cylinder 2. If the key K is turned in a state in which it is not correctly and deeply inserted into the key hole 2.sub.1, the rotation is restricted by the engagement of the cylinder pins 8 having a high rigidity into the tumbler engagement grooves 1.sub.2, thereby preventing a damage to the tumblers 6.

Abstract: A method for controlling the speed of rotation of a motor by changing the resistance value of a resistor circuit connected in series to the motor and having discontinuous resistance values, including the steps of applying voltage across the motor. Detecting when the applied voltage is lower than a first applied voltage and the resistance value of the resistor circuit is a first resistance value and changing the resistance value of the resistor circuit over to a second resistance value lower than the first resistance value. Detecting when the applied voltage detected is higher than a second applied voltage higher than the first applied voltage and the resistance value of the resistor value is the second resistance value and changing the resistance value of the resistor circuit over to the first resistance value.

Abstract: An auto cruise control method and device for a vehicle such as a motorcycle allows the vehicle to operate at a constant set speed while avoiding acceleration or deceleration shock after the auto cruise device is temporarily or permanently operated to change the vehicle speed. Therefore, a smoother ride is provided. Also, a final acceleration change rate can be corrected by considerating factors such as slope, wind, load weight, variation in engine output and non-linearity of engine torque characteristics. Moreover, when the speed is to be changed or when operation of the auto cruise device is to be resumed, the speed of the vehicle can be smoothly shifted.

Abstract: A reverse drive for small vehicles in which an output shaft of a second motor, which is different from the internal combustion engine for running use, can be connected to the transmission line leading from the internal combustion engine to the rear wheel so as to rotate the rear wheel in reverse. The second motor is a starter motor capable of normal and reverse rotations, the normal rotation of the starter motor being transmitted to the internal combustion engine for driving use through a starting clutch, and the reverse rotation of said starter motor being transmitted to the power transmission line through a reverse clutch. Otherwise, the second motor may be a starter motor capable of rotating only in one direction. In this case, the output of the starter motor is transmitted to the output side of the power transmission line through a reverse transmission line while the output transmission line is interrupted.

Abstract: An audio apparatus for a vehicle is disclosed having an audio signal generator, an amplifier operatively connected to the generator for amplifying an audio signal received from the generator, a speaker for emitting sounds and which is driven by the amplifier, a vehicle speed detector, and a gain control operatively connected to the speed detector for generating a control signal and providing it to the amplifier, such that the control signal increases the gain of the amplifier according to an increase in the output of the vehicle speed detector.