Patent ID: 7225793

Claim:
An engine control apparatus for an engine having at least one cylinder, a piston in said cylinder, a crankshaft connected to said piston, said piston being adapted to reciprocate between top dead center position and bottom dead center position defining a combustion chamber having an intake valve controlling the induction of a air and fuel charge mass into said combustion chamber with predetermined timing related to said crankshaft's angular position and a spark plug for igniting the air and fuel charge, said engine air induction system having an air induction chamber contiguous with said intake valve with an intake throttle valve for regulating intake air flow there through and an electronically controlled fuel injector for introducing a metered fuel charge into the intake air mass, the engine control apparatus comprising; (a) a pressure sensing element in communication with said air induction chamber providing an intake pressure signal which fluctuates during an intake event; (b) a pressure signal processing circuit which uses the intake pressure signal to develop at least one timing signal per intake event providing an indication of a crankshaft angular position with in an engine cycle, with the time between timing pulses being an indication of engine crankshaft speed, and an air flow calculation without reference to the physical position of the intake throttle valve or an external main flow sensor; and (c) a fuel injector driver circuit which based on the at least one timing pulse and the air flow signal provides a fuel injector output signal to cause the fuel injector to open at a selected period during an engine cycle and for a duration necessary to inject a charge of fuel in proportion to the intake air charge mass.