Apparatus for generating control signal for controlling operation of internal combustion engine

An apparatus for generating a control signal for controlling operation of an internal combustion engine, comprising:

• a first signal detector for generating a first signal series relating to rotation of a crank shaft of said internal combustion engine;
• a second signal detector for generating a second signal series relating to rotation of a cam shaft driven with a speed reduction ratio of "1/2" relative to said crank shaft;
• and
• control means for controlling at least one parameter involved in operation of said internal combustion engine on the basis of at least one of said first and second signal series;
• said first signal series including an angular position signal generated at every first predetermined angular position in synchronism with the rotation of said crank shaft and a reference position signal generated at every second predetermined angular position corresponding to a reference position of each of the engine cylinders;
• said second signal series containing a cylinder identifying signal, wherein a pulse form of said cylinder identifying signal at least for a given one of the engine cylinders differs from those for the other engine cylinders and wherein a pulse form of said cylinder identifying signal for a group of the engine cylinders which can simultaneously be controlled differs from the other engine cylinder group;
• said control means including:
• reference position signal detecting means for detecting said reference position signal on the basis of said first signal series;
• cylinder group identifying means for identifying said cylinder group on the basis of at least said second signal series;
• cylinder identifying means for discriminatively identifying each of said engine cylinders on the basis of at least said second signal series;
• control timing arithmetic means for arithmetically determining control timings for controlling said parameter or parameters on the basis of the results of the cylinder identification performed by said cylinder identifying means and said second signal series;
• and
• abnormality decision means for generating and outputting an abnormality decision signal to said cylinder identifying means and said control timing arithmetic means upon detection of a failure in said first signal series.