Control device of internal combustion engine, work machine and control method of internal combustion engine

A work machine comprising:

• an internal combustion engine;
• and
• a control device of the internal combustion engine,
• wherein a driving state of the work machine is detected, and based on the detected driving state, the control device controls driving state of the internal combustion engine by using:
• a first relationship of a torque and a rotation speed of the internal combustion engine which is defined to correspond to a case where an amount of fuel injection for the internal combustion engine is maximum at each rotation speed of the internal combustion engine and so that an output at a rotation speed to generate a rated output of the internal combustion engine is equal to or more than the rated output;
• a second relationship of the torque and the rotation speed of the internal combustion engine which is defined to correspond to a case where the amount of fuel injection for the internal combustion engine is zero at each rotation speed of the internal combustion engine and so that the torque of the internal combustion engine decreases in accordance with increase of the rotation speed of the internal combustion engine, where a point where the torque and the rotation speed of the internal combustion engine are zero is defined as a start point;
• and
• a third relationship which is a relationship of the torque and the rotation speed of the internal combustion engine, which is obtained from the first relationship and the second relationship, and
• wherein the driving state of the internal combustion engine is controlled using the third relationship that matches:
• a fourth relationship of the torque and the rotation speed of the internal combustion engine which is defined so that an output corresponding to a command value of an output of the internal combustion engine becomes constant;
• and
• a fifth relationship of the torque and the rotation speed of the internal combustion engine which is set so that a fuel consumption rate with respect to the output of the internal combustion engine becomes the smallest, and
• wherein further, the driving state when a load of the internal combustion engine decreases is controlled using a sixth relationship of the torque and the rotation speed of the internal combustion engine, which is defined from a no-load maximum rotation speed which is a maximum rotation speed of the internal combustion engine when the load of the work machine decreases.

A control method of an internal combustion engine, wherein when the internal combustion engine that is provided in a work machine and that serves as a power source for the work machine is controlled, the control method comprising:

• detecting driving state of the work machine, and
• based on the detected driving state, controlling the driving state of the internal combustion engine by using:
• a first relationship of a torque and a rotation speed of the internal combustion engine which is defined to correspond to a case where an amount of fuel injection for the internal combustion engine is maximum at each rotation speed of the internal combustion engine and so that an output at a rotation speed to generate a rated output of the internal combustion engine is equal to or more than the rated output;
• a second relationship of the torque and the rotation speed of the internal combustion engine which is defined to correspond to a case where the amount of fuel injection for the internal combustion engine is zero at each rotation speed of the internal combustion engine and so that the torque of the internal combustion engine decreases in accordance with increase of the rotation speed of the internal combustion engine, where a point where the torque and the rotation speed of the internal combustion engine are zero is defined as a start point;
• and
• a third relationship which is a relationship of the torque and the rotation speed of the internal combustion engine, which is obtained from the first relationship and the second relationship.