Abstract: A method for detecting knock for an internal combustion engine having a plurality of cylinders in which a vibration sensor is attached to each cylinder and a peak value of vibration detected by the sensor is sampled over a predetermined interval near the top dead center. The sampled value is converted from analog to digital and stored for a predetermined number of sampling times to obtain the average value for each cylinder. Then the frequency of occurrences in which the ratio between the sampled peak value and the average value exceeds a reference value is obtained, and the knock is determined when the frequency of occurrences in any one cylinder exceeds a predetermined value or when the average frequency of occurrences of the all cylinders exceed another predetermined value.

Abstract: A knocking detection method for internal combustion engines in which vibrations of the engine are detected by a vibration sensor and a peak value of the vibrations during a predetermined interval near the top dead center in each revolution of the engine is sampled. The peak value for each revolution is stored for a predetermined number of revolutions of the engine and an average value of the peak values is obtained. Then the ratio of each peak value to the average value is calculated, and the number of ratios whose magnitude exceeds a predetermined magnitude is expressed in terms of a rate or a percentage with respect to the total number of ratios, i.e., the predetermined number of revolutions of the engine. The presence or absence of the knocking is determined whether or not the rate or percentage is above a reference rate or percentage.

Abstract: A method for controlling the ignition timing for the internal combustion engine is disclosed. When it is decided that the engine load is large on the basis of the engine number of revolutions per minute and intake pressure. If the engine is in the knocking condition, a step lead angle is added to the present lead angle value in the range between a set lead angle and a minimum lead angle. If the engine is not in the knocking condition, on the other hand, a step lead angle is subtracted from the present lead angle value in the above-mentioned range. By contrast, when it is decided that the engine load is small on the basis of the engine r.p.m. and intake pressure. The lead angle control of the present lead angle value is stopped so that the present lead angle is set at the above-mentioned set lead angle or the minimum lead angle value.

Abstract: An electronic ignition timing control system comprises a plurality of double ignition coils each being connected to the spark plugs of each set of two cylinders in a multi-cylinder engine. In addition to a large number of teeth on the periphery of the engine ring gear, there is provided a reference tooth at a predetermined angular crankshaft position for a selected set of the cylinders. The reference angular positions for the other sets of the cylinders are calculated arithmetically. A circuit including read-only-memories determines a desired ignition angle in accordance with engine operating parameters to produce a binary code signal consisting of higher order bits and lower order bits. A first comparator starts to count the number of teeth on the ring gear at the time of the detection of a reference angular position to roughly determine the ignition timing, the first comparator producing an output signal when the count value thereof reaches that of the higher bits.

Abstract: Ignition timing control for an internal combustion engine is achieved by sensing engine rotation so as to generate output pulses for predetermined degrees of rotation and to develop a reset pulse at a rotational reference position. A first digital signal representing rotational speed of the engine and a second digital signal representing engine intake vacuum are converted into output date representative of optimum retard angles from the reference position. The output date are added to generate a plural bit binary signal having higher and lower significant bits. Comparison means, responsive to the reset pulse, counts the output pulses representing degrees of engine rotation and generates an output signal when the count reaches the value of the higher significant bits.

Abstract: In response to the input signal corresponding to the rotational speed of an internal combustion engine, a first read-only memory generates a binary coded signal indicative of the corresponding preliminarily written ignition retard angle from a predetermined angular position of the engine crankshaft, and in response to the input signal corresponding to the intake manifold vacuum a second read-only memory generates a binary coded signal indicative of the corresponding preliminarily written ignition retard angle. The output signals of the read-only memories are added together by an adder. A comparator compares the output signal of the adder with the number of clock pulses corresponding to the rotational angle of the crankshaft, and the ignition timing is determined by the output of the comparator.

Abstract: An electronic ignition timing control system for an internal combustion engine which comprises a rotational angle detector for detecting a rotational angle of the engine to produce output pulses, a reference angle detector for detecting a reference rotational angle of the engine to produce a reset pulse, an ignition angle computing circuit for converting by interpolation the advance angles corresponding to principal points of engine parameter address into the retard angles from the reference angle to produce a first output signal indicative of an angle corresponding to the rotational angle of the engine and a second output signal indicative of the delay time corresponding to an angle smaller than the first output signal value, a first comparator to digitally compare the first output value of the ignition angle computing circuit with the number of the output pulses of the rotational angle detector, and a second comparator to convert the second output value of the ignition angle computing circuit into a time pe

Abstract: A recording system for a vehicle occupant protecting apparatus wherein operating conditions of the various components of the occupant protecting apparatus are recorded, when the occupant protecting apparatus such as an air bag properly comes into operation, when conditions are detected which require the operation of the occupant protecting apparatus although its actual operation does not take place or when any fault occurs in the occupant protecting apparatus, thereby to know the various conditions and circumstances which existed during the collision or under the fault condition.