Apparatus for producing an engine-speed signal for an electronic fuel injection system

An electronically controlled fuel injection system comprising, in combination:

• a. signal generating means for producing a first train of pulses in which the pulse intervals are dependent upon engine RPM;
• b. signal processing means, connected to said signal generating means, for producing a second train of pulses in which the pulse intervals are dependent, at least approximately, upon the mean value of pulse intervals in said first pulse train within a given pulse sequence, thereby at least reducing pulse interval changes of short duration, said signal processing means including:
• 1. pulse frequency divider means connected to said signal generating means;
• 2. integrator means connected to said pulse frequency divider means;
• 3. pulse frequency multiplier means connected to said integrator means, said pulse frequency divider means and said pulse frequency multiplier means having the same factor of division and multiplication, respectively, so that the output of said pulse frequency multiplier means exhibits approximately the same pulse frequency as said first pulse train;
• and
• 4. trigger means, connected to said pulse frequency multiplier means, for producing an output signal whenever the input thereto reaches a prescribed value;
• and
• c. fuel injection means, connected to said signal processing means, for injecting fuel into an internal combustion engine upon receipt of said pulses of said second pulse train.