Idle speed control system for a two-cycle engine

Claim 1

In an idle speed control system for a two cycle engine having a cylinder with a scavenge port and an exhaust port, an intake passage communicated with said scavenge port, an exhaust passage connected to said exhaust port, a fuel/air injection for directly and simultaneously injecting an amount of fuel and air into said cylinder, a scavenge pump provided in said intake passage for supplying compressed air into said cylinder, a control valve interposed in a bypass of said intake passage, an engine speed sensor for detecting engine speed and for producing a corresponding engine speed signal, and an accelerator position sensor for detecting depressing degree of an accelerator pedal operatively connected with said control valve and for producing a corresponding degree signal, the improvement of the system which comprises: idling state detecting means responsive to said engine speed and said degree signals for detecting an idling state of said engine by comparing said engine speed and degree signals with values stored in a memory of engine speed and depressing degree of said accelerator pedal representing the idling state and for producing an idling state signal when said signals correspond with said values representing the idling state; engine operating condition detecting means responsive to said engine speed and said degree signals for detecting an engine operating condition and for producing a corresponding engine operating condition signal; idle speed determining means responsive to said engine speed signal and said idling state signal and for determining an idle speed and for producing a corresponding idle speed signal; fuel control means responsive to said idle state and said engine operating condition signals for controlling a quantity of fuel injection to said injector; and air control means responsive to said idle state and said engine operating condition signals for controlling quantity of air injection in combination with said fuel injection to said injector and at least one of said control means being responsive to said idle speed signal for correcting the corresponding quantity of injection, so that the engine speed immediately converges to an optimum idling engine speed without overshooting.