Reverse rotation control system for two-cycle engine of motor vehicle

A reverse rotation control system for a two-cycle engine mounted on a motor vehicle, comprising:

• a variety of sensors for generating a variety of information signals in correspondence to engine operation states,
• said variety of sensors including a brake switch for generating a brake signal upon braking operation;
• and
• an idle switch for generating an idle signal when an acceleration pedal is released,
• wherein said reverse rotation enabling condition decision means decides that said reverse rotation enabling conditions are met when said engine rotation number indicates an engine rotation number corresponding to the idling rotation number and when both of said brake signal and said idle signal are inputted;
• and
• an ignition control unit for outputting an ignition signal for said engine on the basis of said variety of information signals,
• said variety of sensors including at least a rotation sensor for outputting a rotation signal corresponding to rotation of said engine and a reverse rotation switch for generating a reverse rotation command signal for reversing engine rotation,
• said ignition control unit including:
• ignition timing retarding control means for causing ignition timing of said engine to retard beyond a top dead center upon inputting of said reverse rotation command signal;
• engine rotation number decision means for deciding whether or not rotation number of said engine is lowered to a first predetermined engine rotation number;
• misfire period arithmetic means for determining arithmetically a misfire period on the basis of said engine operation states when said engine rotation number is lowered to a first predetermined engine rotation number;
• misfire means for causing misfire to occur in said engine over said misfire period;
• overadvanced ignition means for outputting only once an ignition signal overadvanced relative to an ordinary advanced ignition timing upon termination of said misfire period;
• and
• reverse rotation condition decision means for making decision upon inputting of said reverse rotation command signal as to whether or not said engine operation state satisfies reverse rotation enabling conditions,
• wherein said ignition timing retarding control means is validated only when said reverse rotation enabling conditions are satisfied,
• wherein said misfire period corresponds to a time period required for said engine rotation number to lower from said first predetermined engine rotation number to a second predetermined engine rotation number,
• wherein said first predetermined engine rotation number is set at a value smaller than an idling rotation number of said engine, and
• wherein said second predetermined engine rotation number is set at a value which is smaller than first predetermined engine rotation number and which is suited for the reverse rotation rotation control.

A reverse rotation control system for a two-cycle engine mounted on a motor vehicle, comprising:

• a variety of sensors for generating a variety of information signals in correspondence to engine operation states,
• said various sensors further including a temperature sensor for outputting a temperature information signal indicating temperature of said engine,
• wherein said misfire period arithmetic means determines arithmetically said misfire period on the basis of said rotation signal and said temperature information signal;
• and
• an ignition control unit for outputting an ignition signal for said engine on the basis of said variety of information signals,
• said variety of sensors including at least a rotation sensor for outputting a rotation signal corresponding to rotation of said engine and a reverse rotation switch for generating a reverse rotation command signal for reversing engine rotation,
• said ignition control unit including:
• ignition timing retarding control means for causing ignition timing of said engine to retard beyond a top dead center upon inputting of said reverse rotation command signal;
• engine rotation number decision means for deciding whether or not rotation number of said engine is lowered to a first predetermined engine rotation number;
• misfire period arithmetic means for determining arithmetically a misfire period on the basis of said engine operation states when said engine rotation number is lowered to a first predetermined engine rotation number;
• misfire means for causing misfire to occur in said engine over said misfire period;
• and
• overadvanced ignition means for outputting only once an ignition signal overadvanced relative to an ordinary advanced ignition timing upon termination of said misfire period,
• wherein said misfire period corresponds to a time period required for said engine rotation number to lower from said first predetermined engine rotation number to a second predetermined engine rotation number,
• wherein said first predetermined engine rotation number is set at a value smaller than an idling rotation number of said engine, and
• wherein said second predetermined engine rotation number is set at a value which is smaller than first predetermined engine rotation number and which is suited for the reverse rotation rotation control.