Abstract: An automotive emission control system includes a servo connected between the carburetor and the distributor and between an engine driven air pump and the distributor to advance the ignition timing as a function of changes in carburetor spark port vacuum and/or air pump pressure to provide various degrees of timing advance and retard; the servo includes a pair of diaphragms that are interconnected so that movement of one advances the timing by a first amount, the second advancing the timing independently of the other and being additive or the only advance.

Abstract: A multi-stage engine ignition timing control providing dual stages of advance movement by the use of carburetor spark port vacuum applied to one diaphragm and engine driven air pump pressure applied to a second diaphragm, and the use of a constant reference pressure against one or both of the diaphragms to render the movements independent of barometric pressure changes, and including a one-way coupling to effect a retarded ignition timing setting upon switching of the actuating force acting against the one diaphragm from spark port vacuum to air pump pressure.

Abstract: A distributor for use in the electrical system of an internal combustion engine, providing an increased angle of registration between a rotor element and each spark plug contact within the distributor. The rotor element is provided with a plurality of conductive rotor arms which, upon rotation, alternately register with spark plug contacts circumferentially disposed about the rotor element, wherein each spark plug contact is associated with one of the plurality of rotor arms. In one embodiment, each rotor arm includes a plurality of blades which are disposed to rotate into simultaneous registration with a single high voltage supply contact and a spark plug contact. In a second embodiment, each rotor arm includes a plurality of blades disposed to rotate into simultaneous registration with sequentially disposed ones of a plurality of high voltage supply contacts and a spark plug contact.

Abstract: An automotive type engine has an ignition timing control that includes a vacuum controlled servo that is responsive to spark port vacuum changes to provide a first advance increment, and EGR port vacuum providing an additional incremental advance, coupled with a source of air at constant pressure acting on the servo as a reference pressure to render the ignition timing changes insensitive to barometric pressure changes occasioned by changes in altitude of the vehicle in which the timing control servo is installed.