Abstract: An apparatus (8) is provided for controlling ignition in an engine having a ignition system (10), an engine cylinder sensor (48), and a piston disposed in the cylinder and being movable to a top dead center (TDC) position. The cylinder sensor (48) produces a first signal representing the position of the piston within the cylinder and having a frequency responsive to engine speed. The ignition system (10) includes a transformer (24) having a primary coil (26) which is energized in response to a cylinder select signal to produce sparking across an associated spark plug gap (22). A first circuit (98) is provided for sensing a delay between production of the cylinder select signal and the time at which current through a respective primary coil exceeds a preselected current level, and responsively producing a timing error signal.

Abstract: A method and apparatus is provided for measuring detonation in an internal combustion engine. Vibration sensors located on the engine send signals through a filter which is turned to the cavity resonance of the engine's cylinders. The peaks and valleys of the filtered signals are detected and ratiometrically compared one with another to determine the magnitude of detonation. The detonation information may be used by an engine control to retard timing in response to a predetemined level of detonation.

Abstract: Apparatus for determining the speed of an engine (10) and the phase shift between first and second shafts (16,19) rotatably driven by the engine (10). First and second fixed magnetic sensors (50,56) generate first and second signals (49,55) in response to movement of magnetically sensible members (47,53) through circular paths at speeds proportional to the speeds of the first and second shafts (16,19), respectively. Clock pulses from a fixed frequency clock (65) are counted to obtain a first count between successive first signals (49) and a second count between successive second and first signals (55,49). The first count is inverted to obtain information as to the instantaneous engine speed. The second count is divided by the first count to obtain information as to the instantaneous phase angle between the first and second shafts (16,19). Successive instantaneous information is averaged to cancel the effects of engine torsionals.

Abstract: An electronic engine control system (10) utilizing a digital microprocessor (30) for controlling the timing mechanism (13) and fuel pump rack limit (23) to set the engine timing of, and maximum allowable rate of fuel delivery to, an interval combustion engine (11) so that maximum engine performance is obtained with smoke and emissions limited to required EPA levels. A plurality of timing maps (61-64) are provided, for different modes of engine operation, each map having predetermined value timing control signals programmed therein corresponding to the optimal timing advance of a particular engine speed, or particulaoptimoptimal timing advance of a particular engine speed, or particular combination of engine speed and position of the fuel rack (21). A timing map selector (65) identifies the mode of engine operation and selects the appropriate timing map (61-64) to control the timing mechanism (13) by the particular programmed signal for the existing engine speed and fuel rack position.