Patent ID: 7197391
Filing Date: 2007-03-27
Classification: F02D,Y02T

Abstract:
1. An apparatus for controlling an engine using a cam signal in addition to a crank signal, the cam signal including a series of changes between high and low levels in a predetermined waveform pattern, same directed edges of the changes of the cam signal corresponding to angular positions of rotation of a camshaft of the engine, the crank signal including a train of crank pulses whose same-directed edges correspond to angular positions of rotation of a crankshaft of the engine, the angular positions of rotation of the camshaft being associated with those of rotation of the crankshaft, the apparatus comprising: an edge interval measuring unit configured to receive an input signal including a series of changes between high and low levels and to measure an edge interval of temporally adjacent same-directed edges of the input signal; an input unit configured to input the crank signal as the input signal to the edge interval measuring unit, the edge interval measuring unit measuring one of edge intervals of temporally adjacent same-directed edges of the crank signal; a multiplication clock signal generating unit configured to generate a multiplication clock signal including a train of clock pulses whose clock cycle is an integral number submultiple of the measured edge interval; a count unit configured to count in synchronization with the multiplication clock signal; an abnormality determining unit configured to determine whether the crank signal is abnormal; a switching unit configured to switch the input signal to the edge interval measuring unit from the crank signal to the cam signal when it is determined that the crank signal is abnormal, the edge interval measuring unit measuring an edge interval of temporally adjacent same-directed edges of the cam signal; and a count-value control unit configured to: identify the angular positions of the crankshaft based on the cam signal to initialize a count value of the count unit based on the identified angular positions of the crankshaft; and change the integral number based on the predetermined waveform pattern of the cam signal to shift the count value of the count unit as in the case of the crank signal inputting to the edge interval measuring unit.