Hitachi, Ltd.

Terumi Okado

Noboru Sugiura

Seiji Suda

Kazutoshi Kobayashi

Hitoshi Minorikawa

Takashi Yoshinari

Hiroshi Fujiwara

A knock control system which includes a knock control unit constructed of a transducer portion for detecting vibrations of an engine and converting the detected vibrations into an electric signal, and a knock signal processing unit for delivering a signal indicative of the occurrence of a knock in dependence upon a receipt of the knock signal from the transducer portion. The knock signal processing circuit controls the ignition timing of the internal combustion engine on the basis of the knock signal from the knock control unit. At least one of the transducer portion and the knock signal processing circuit unit of the knock control system is mounted on a portion of a distributor which has a fixing base portion at a part of the housing thereof.

Knock control system

A knock control apparatus equipped with an altitude compensation function is disclosed. The apparatus comprises a knock sensor fitted to an internal combustion engine and detecting the mechanical oscillation of the engine; a background signal detection circuit discriminating the background level signal of the knock signal from the output signal of the knock sensor; a comparator for comparing the output signal of the knock sensor with the background signal and detecting knock and the intensity of knock; and a knock control circuit sequentially advancing the ignition timing of the internal combustion engine towards the maximum advance angle position and retarding the ignition timing in accordance with the occurrence of knock and its intensity so as to control and optimize the ignition timing of the engine. The knock control apparatus further includes an atmospheric pressure sensor and changes the maximum advance angle position of the ignition timing in accordance with the output signal of this atmospheric pressure sensor.

Knock control apparatus equipped with altitude compensation function

An ignition retard angle control apparatus for an internal combustion engine is disclosed. This control system comprises a vibration sensor for detecting engine vibrations, a filter for discriminating part of the output of the sensor in a characteristic frequency range where a knock-induced vibration component appears remarkably when a knock is generated, an amplifier for amplifying the output signal of the filter, an averaging/amplifying device for macroscopically averaging and amplifying the output signal of the filter, a comparator for comparing the output of the amplifier with those of the averaging/amplifying device and producing an output signal when the former is larger than the latter, an engine rpm detector for detecting the engine speed, and a voltage signal generator circuit responsive to the output signals of the comparator and the engine rpm detector and having an output of an amplitude corresponding to the ignition advance angle determined in accordance with the engine rpm, the voltage signal generator circuit changing the amplitude of the output voltage thereof in a manner to retard the ignition advance angle by a predetermined amount in response to an output signal of the comparator.

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Katsuta, Japan

Terumi Okado