Fuel injection quantity control device for two cycle engines

A fuel injection quantity control device for use with a two cycle engine being rotatably driven by receiving a fuel-air mixture injected into the engine based on fuel injection quantity instruction signals and the air supplied through an intake passage and ignition of the fuel-air mixture in a combustion chamber comprising:

• a rotational speed Ne detection device for detecting the rotational speed Ne of the two cycle engine and for generating a rotational speed Ne signal;
• an opening .THETA. detection device for detecting the opening .THETA. of a throttle provided in an intake passage for regulating the supply of air and for generating an opening .THETA. signal;
• a basic injection quantity setting device for setting a basic injection quantity of the fuel based on the rotational speed, Ne signal and the opening .THETA. signal;
• a fuel-air mixture condition judging device for judging the conditions of the fuel-air mixture;
• and
• an injection quantity instruction signal generating device for correcting the basic injection quantity to reduce the quantity in response to misfire in said fuel-air mixture for changing the conditions of the fuel-air mixture ignition, and for outputting the corrected basic injection quantity as an injection quantity instruction signal;
• said fuel-air mixture condition judging device judges a misfire at the present time based on a misfire in the past;
• said fuel-air mixture condition judging devices comprises:
• a negative pressure PB detection section for generating a negative pressure PB signal by detecting negative pressure in said intake passage;
• an indicated pressure PI detection section for detecting the indicated pressure PI in said combustion chamber and for generating an indicated pressure PI signal;
• a first misfire judging section for judging based on said negative pressure PB signal whether or not misfire exists in said fuel-air mixture;
• and
• a second misfire judging section for judging based on said indicated pressure PI signal whether or not misfire exists in said fuel-air mixture;
• and
• said injection quantity instruction generating device comprises:
• a first correction section for correcting said basic injection quantity to reduce the injection when said first misfire judging section judges misfire;
• and
• a second correction section for correcting said basic injection quantity to reduce the injection when said second misfire judging section judges misfire;
• and
• said first correction section reduces said basic injection quantity by a quantity smaller than the quantity in said second correction section.

A fuel injection quantity control device for use with a two cycle engine being rotatably driven by receiving a fuel-air mixture injected into the engine based on fuel injection quantity instruction signals and the air supplied through an intake passage and ignition of the fuel-air mixture in a combustion chamber comprising:

• a rotational speed Ne detection device for detecting the rotational speed Ne of the two cycle engine and for generating a rotational speed Ne signal;
• an opening .THETA. detection device for detecting the opening .THETA. of a throttle provided in an intake passage for regulating the supply of air and for generating an opening .THETA. signal;
• a basic injection quantity setting device for setting a basic injection quantity of the fuel based on the rotational speed, Ne signal and the opening .THETA. signal;
• a fuel-air mixture condition judging device for judging the conditions of the fuel-air mixture;
• and
• an injection quantity instruction signal generating device for correcting the basic injection quantity to reduce the quantity in response to misfire in said fuel-air mixture for changing the conditions of the fuel-air mixture to ignition, and for outputting the corrected basic injection quantity as an injection quantity instruction signal;
• said fuel-air mixture condition judging device judges a misfire at the present time based on a misfire in the past;
• said fuel injection quantity control device further comprises:
• a stretched-out condition detection device for detecting based on said rotational speed Ne signal and said opening signal said stretched-out condition of said two cycle engine, and outputs a stretched-out condition signal;
• a continuation time counter for receiving said stretched-out condition signal and for counting reception continuation time of said stretched-out condition signal and for outputting stretched-out time signal;
• and
• an injection quantity instruction signal generating device for correcting said basic injection quantity to increase the quantity based on said stretched-out time signal and outputs said corrected basic injection quantity as said injection quantity instruction signal.