US 4,224,917 AGranted

Ignition device

AssigneeHitachi, Ltd.

InventorsTerumi Nakazawa, Hitoshi Minorikawa, Kazutoshi Kobayashi, Hiromitsu Nagae, Tomoji Inui

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Abstract

This invention relates to an ignition device of the type wherein a pickup coil for making a signal synchronous with the engine revolution is disposed within a distributor, an amplifier circuit for amplifying the output of the pickup coil and a power transistor for controlling the primary coil current of an ignition coil are arranged in a circuit unit under hybrid IC and chip states respectively, and the circuit unit is mounted on a side surface of a housing of the distributor. A highly waterproof structure has been found necessary in order that the insulation between the housing and pickup terminals as well as connectors for coupling the pickup coil and the amplifier circuit and the insulation between the terminals may be prevented from degrading due to moisture. To this end, a protuberance which projects from the circuit unit into the housing is disposed in a manner to surround the pickup terminals.

In an ignition device comprising:

a signal generator means for generating a signal synchronous with the revolution of an engine;
amplifier means for detecting the output of the signal generator means and amplifying it;
a d.c. power source;
a power transistor which operates in response to an output of said amplifier means,
an ignition coil which has at least a primary coil;
connection means for connecting said primary coil of said ignition coil and said power transistor in series with said d.c. power source so that a current flowing through said primary coil of said ignition coil can be controlled by the operation of said power transistor;
and
a distributor which distributes an output of a secondary coil of said ignition coil to respective ignition plugs of the engine;
said amplifier means detecting the output of said signal generator means, the resultant output operating said power transistor to control the primary coil current of said ignition coil and to produce a high voltage, said high voltage being distributed to the respective ignition plugs by said distributor;
the improvement therein comprising:
attachment means for mounting said signal generator means within said distributor so as to deliver the output in response to the operation of said distributor;
a circuit unit including waterproof housing means in which said power transistor and said amplifier means are arranged;
attachment means for mounting the waterproof housing means of said circuit unit on an outer surface of a housing of said distributor;
pickup terminals which project from said circuit unit into said distributor;
and
said waterproof housing means including a protuberance integral therewith which projects therefrom into an aperture of said distributor and which surrounds said pickup terminals;
said signal generator means and said amplifier means being connected through said pickup terminals whereby there results a highly waterproofed arrangement.

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Abstract

Claims5