Nippondenso Co., Ltd.

Ryosuke Tachi

Takeshi Matsui

Akio Kobayashi

Yukihide Niimi

Takashi Harada

Katsuharu Hosoe

Teruyoshi Ito

Motoshi Kawai

Teruyoshi Itoh

Hideo Ohyama

Kiyotaka Sasaki

Takeski Matsui

Katsunori Iwamoto

Takao Nojiri

A method and a system for controlling the ignition timing of internal combustion engines, or more in particular for preventing engine over-revolutions by reducing the engine speed when it becomes excessively high. The ignition timing control system is realized by a microcomputer, so that when the engine speed exceeds a predetermined high level, ignition stop operations by an ignition stop unit and ignition retard operations by a retarded ignition unit are repeated as many times as determined by the number of cylinders involved to reduce the engine speed. When the engine speed is in a predetermined high range, the ignition retardation is controlled by feedback in accordance with the engine speed, and further controlled in combination with the ignition stop as required. The method and system according to the invention is suitably used for a multi-cylinder internal combustion engine having an ignition system of electronic distribution type with a carburetor and a simultaneous ignition coil.

Ignition timing control system for internal combustion engines

An electronic control apparatus for use in vehicles comprised of two, one-chip microcomputers. The microcomputers each have a ROM and a RAM and are used to control different systems provided in the vehicle. The ROM of the second microcomputer stores an operational program which can be used to calculate control values for controlling various types of devices. It also stores operational map data which can be used to calculate control values for controlling various types of devices. Various signals output by the sensors provided in the vehicle are supplied to both microcomputers. At the start of the power supply to the apparatus, the operational map data stored in the ROM of the first microcomputer, which is to be used by the second microcomputer, is transferred to the RAM of the second microcomputer. The second microcomputer calculates a control value from the transferred operational map data, the signals output by the sensors and other data, thereby controlling the system assigned to it.

Electronic control apparatus including microcomputers for controlling

An apparatus for controlling the spark timing of an internal combustion engine comprises means for generating a reference position signal with reference to a predetermined engine crankshaft position; waveform shaping means for generating a reference pulse signal having a leading edge advanced with respect to the predetermined crankshaft position as a function of the engine speed, in accordance with the reference position signal; means for detecting the amount of engine load; means for detecting the rotational speed of engine; means for computing a period of time elapsed from the leading edge of the reference pulse in accordance with the detected engine load and engine speed in order to establish a spark timing; means for detecting the variation of period between the leading edge and trailing edge of the reference pulse in relation to each cylinder; and means for correcting the computed period of time in accordance with the detected variation and for generating an output signal causing ignition to occur after the elapse of corrected period of time. The computer estimate spark timing for each cylinder is corrected in accordance with the variation of a period between the leading edge and the trailing edge of the reference pulse, resulting in an optimum spark timing without variation among individual cylinders.

Method and apparatus for controlling spark timing in internal combustion

In response to a predetermined engine crankshaft position a reference pulse is generated having a leading edge advanced with respect to that predetermined position as a function of the rotational speed of the crankshaft. At low engine speeds the reference pulse is directly used as the ignition current. A start-of-dwell-time data word is derived in response to the trailing edge of the reference pulse and an end-of-dwell-time data word is derived in response to the leading edge of a subsequent reference pulse. These data words are used for engine operations at constant high speeds to advance the beginning and end of the dwell time of ignition current by an amount commensurate with an increase in engine speed. When the engine is rapidly accelerated the dwell time is started in response to the leading edge of the reference pulse and terminated when the end-of-dwell-time data word is decremented to zero.

Optimizing spark timing control apparatus and method

Growing community of inventors

Kariya, Japan

Ryosuke Tachi