Abstract: A diaphragm device utilized, for example, in a vacuum advance mechanism of a distributor of an internal combustion engine is disclosed. The diaphragm device comprises: a housing consisting of two cup-shaped members coupled to each other at the marginal flanges thereof; a diaphragm extending in the housing to define an airtight chamber therein; and a control rod coupled to the diaphragm to transmit the motion thereof. The outer marginal portion of the diaphragm is clamped between the flanges of the two cup-shaped housing members, wherein the distance between the radially extending flanges clamping the diaphragm therebetween is strictly controlled by a distance regulator, which may be constituted by a step formed in the outer portion of one of the flanges toward the other flange, the outer marginal portion of the diaphragm being received in the stepped-down inner portion of the stepped flange.

Abstract: A method of and apparatus for generating a cylinder discriminating signal in a distributor for an internal combustion engine are disclosed. The cylinder discriminating signal is generated by a combination of a cylinder discriminating reluctor installed on a centrifugal spark advance member and a cylinder discriminating sensor attached to a vacuum spark advance plate to detect approach and passage of the cylinder discriminating reluctor. The width of the cylinder discriminating reluctor in the direction of rotation is set so as to correspond to an angle smaller than the entire range of spark advance of the ignition timing signal. The cylinder discriminating signal is advanced by both centrifugal spark advance and vacuum spark advance so as to overlap the ignition timing signal despite having a relatively narrow width. Since the width of the cylinder discriminating signal is reduced, it is possible to improve the control tolerances of the associated microcomputer.

Abstract: This invention relates to an ignition distributor for an internal combustion engine and more specifically relates to a novel reluctor included in an ignition distributor for discriminating between cylinders of an engine. The reluctor has an elongated shape and is arranged relative to the rotating shaft of an ignition distributor so that the gravity center of the reluctor is located exactly on the rotational axis of the shaft. This arrangement enables the rotational movement of the shaft to be concentrated, so that the wear to which the bearings supporting the shaft is subjected is significantly reduced. The reluctor is attached to the governor base of an ignition distributor without any rivets by virtue of the novel configuration thereof, so that a reduction in the number of parts can be achieved, together with reduction in the total production cost.

Abstract: A distributor for an internal combustion engine includes an ignition timing reluctor provided on a centrifugal spark advance member, ignition timing signal generating means for generating an ignition timing signal by detecting approach and passage of the ignition timing reluctor, a cylinder discriminating reluctor provided on the centrifugal spark advance member, and a cylinder discriminating sensor for generating a cylinder discriminating signal by detecting approach and passage of the cylinder discriminating reluctor. The distributor has a structure for compensating for any imbalance of its rotator. The cylinder discriminating signal is centrifugally advanced in the same way as the ignition timing signal, so that it is possible to reduce the width of the cylinder discriminating signal.