Abstract: Absolute engine position sensing is provided by monitoring the temporal relationship of energization of multiple spark plugs sharing a common source of drive energy in a direct ignition application. The spark plugs are connected across the source with opposing electrical polarity, and the relative time of discharge across the plugs compared by sensing the time and polarity of high speed transient activity in proximity to the source.

Abstract: An inductive ignition circuit, comprising a secondary winding across a spark plug and a primary winding in series with a lossy transistor switch and a power source, is subject to ringing at the start of the dwell period which can cause premature combustion. Ringing is suppressed by a short switch turn on pulse followed by a short delay prior to the main dwell period, causing a beginning build up of primary current and circuit energy followed by absorption of energy in the switch during switching to dissipate circuit energy needed for oscillation. Preferably, the short pulse is terminated when all the ringing energy is stored in the leakage inductance of the ignition coil.

Abstract: A method and apparatus for enhancing the cold starting performance of a spark ignition, internal combustion engine fueled with an alcohol-based fuel mixture is described. The quantity of fuel mixture delivered to the engine is regulated to establish a combustible fuel vapor-air mixture in each engine cylinder during cranking, while restricting the accumulation of unvaporized fuel in the each cylinder so as not to exceed a predetermined amount. In addition, each cylinder spark plug is provided with an ignition current having a peak magnitude sufficient to achieve voltage break down across each spark plug arc gap, when each gap is resistively loaded due to wetting in accordance with the predetermined amount of accumulated unvaporized fuel. Preferably, the quantity of fuel delivered to the engine during cranking is reduced at a substantially exponential rate as a function of the cumulative number of revolutions the engine is rotated during cranking.

Abstract: An inductive ignition system for a spark ignited internal combustion engine. An N-channel field effect transistor (FET) is connected in series with the primary winding of an ignition coil. The primary winding and the FET are connected in a high side drive connection. An NPN transistor has its collector-emitter circuit connected between the gate and source of the FET. When the FET is biased off a flyback voltage is developed across the primary winding which is used to bias the NPN transistor conductive thereby clamping the gate and source voltage of the FET together to keep the FET switched off.

Abstract: A hot element anemometer uses solid state diode chips for the heated air flow sensing element and the ambient temperature sensing element in parallel circuit branches. The air flow sensing element carries a heating resistor on the diode chip. Constant current sources of equal value supply current through the diodes. The air flow sensor diode is in series with a resistor which determines the nominal temperature difference between the diode chips. A circuit compares voltages in the two diode branches and provides an air flow output signal and controls the temperature of the air flow sensor diode. To compensate for changes of thermal conductivity of the air temperature and various temperature effects in the circuit, a third current source is coupled to the ambient temperature sensing branch through a resistor network and includes resistors that can be adjusted to provide a functional calibration which yields an air flow signal free of linear temperature effects.