Method and device for controlling the transition between normal operation and overrun fuel cut-off operation of an otto engine operated with direct fuel injection

A method for controlling the transition between a normal operation mode of a direct fuel injected Otto engine and an overrun fuel cut-off operation mode of the engine, comprising:

• adjusting an ignition angle in a retarded ignition direction in order to reduce a torque jump;
• and
• injecting fuel into a cylinder of the engine in the form of multiple injections,
• wherein a quantity of the injected fuel is injected into the engine during a compression phase of the Otto engine cycle.

A engine mode switchover apparatus that controls the transition between a normal operation mode of an Otto engine and an overrun fuel cut-off operation mode of the engine and a return to the normal operation mode of the engine, comprising:

• a fuel injector that injects fuel into a cylinder of the engine;
• a device that determines a torque output of the engine;
• a device that measures an ignition angle;
• a device that stores a plurality of engine parameters;
• a device that adjusts the ignition angle and an intake air mass of the engine;
• and
• a device that controls the fuel injection having a control program, the control program adapted to reduce the ignition angle and subsequently inject the fuel into the cylinder during the compression phase of the engine.

An engine management system that controls the transition between a normal operation mode of an Otto engine and an overrun fuel cut-off operation mode of the engine and return to the normal operation mode of the engine, comprising:

• a device for determining an angle of rotation of a crank shaft of the engine;
• a throttle valve actuator;
• an engine speed sensor;
• a fuel injector that injects fuel directly into a cylinder of the engine;
• a device that determines a torque output of the engine;
• a device for measuring an ignition angle;
• a device for storing a plurality of engine parameters;
• a device for adjusting the ignition angle and an intake air mass of the engine;
• and
• a device that controls the fuel injection having a control program, the control program adapted to reduce the ignition angle and subsequently inject the fuel into the cylinder during the compression phase of the engine.