Hybrid vehicle and control method thereof

1. A hybrid vehicle comprising:

an internal combustion engine that outputs an engine driving force;

a motor that outputs a motor driving force;

an accumulator that supplies and receives electric power from the motor;

a shift position selecting device that allows a driver to select a neutral position and a drive position;

an accelerator operation amount acquisition device that acquires an accelerator operation amount by the driver;

a limit driving force setting module that sets a limit driving force that is a target value of a total driving force of the engine driving force and the motor driving force to reduce a behavior unstable state including at least a state in which a wheel spin occurs when the hybrid vehicle is in the behavior unstable state;

a limit driving force setting release device that allows the driver to release a setting of the limit driving force by the limit driving force setting module;

a target driving force setting module that sets a driving force demand for driving the vehicle based on the acquired accelerator operation amount, the target driving force setting module setting a target driving force that is a target value of a driving power based on the set driving force demand in response to a non-satisfaction of a predetermined condition upon a shift from the neutral position to the drive position, the target driving force setting module setting the target driving force so as to gradually change in comparison with that on the non-satisfaction of the predetermined condition based on the set driving force demand and a predetermined gradual change restriction until a satisfaction of a predetermined release condition in response to a satisfaction of the predetermined condition upon the shift from the neutral position to the drive position, the predetermined condition being configured to gradually change the target driving force through an annealing with a time constant, the target driving force setting module setting the target driving force based on the driving force demand as well as on the non-satisfaction of the predetermined condition regardless of whether or not the predetermined condition is satisfied when the setting of the limit driving force by the limit driving force setting module is released; and

a control module that controls the internal combustion engine and the motor so as to ensure the total driving force is equivalent to the set target driving force.

2. The hybrid vehicle according to claim 1 , further comprising an electric power-mechanical power input output structure connected to a predetermined axle and an engine shaft of the internal combustion engine and outputting at least a part of power from the internal combustion engine to an axle side with input/output of electric power and mechanical power, the electric power-mechanical power input output structure supplying and receiving electric power from the accumulator,

wherein the motor is capable of outputting power to the predetermined axle or another axle different from the predetermined axle.

3. The hybrid vehicle according to claim 2 , wherein the electric power-mechanical power input output structure includes a power generation motor capable of inputting and outputting power and supplying and receiving electric power from the accumulator, and a three shaft-type power input output assembly connected with three shafts, the predetermined axle, the engine shaft of the internal combustion engine, and a rotating shaft of the power generation motor, the three shaft-type power input output assembly configured to input and output power to one remaining shaft, based on input and output of powers from and to any two shafts selected among the three shafts.

4. A control method of a hybrid vehicle including an internal combustion engine that outputs an engine driving force, a motor that outputs a motor driving force, an accumulator that supplies and receives electric power from the motor, and a shift position selecting device that allows a driver to select a neutral position and a drive position, a limit driving force setting module that sets a limit driving force that is a target value of a total driving force of the engine driving force and the motor driving force to reduce a behavior unstable state including at least a state in which a wheel spin occurs when the hybrid vehicle is in the behavior unstable state, a limit driving force setting release device that allows the driver to release a setting of the limit driving force by the limit driving force setting module, the control method comprising:

(a) setting a driving force demand for driving the vehicle based on an accelerator operation amount by the driver, the Step (a) setting a target driving force that is a target value of a driving power based on the set driving force demand in response to a non-satisfaction of a predetermined condition upon a shift from the neutral position to the drive position, the Step (a) setting the target driving force so as to gradually change in comparison with that on the non-satisfaction of the predetermined condition based on the set driving force demand and a predetermined gradual change restriction until a satisfaction of a predetermined release condition in response to a satisfaction of the predetermined condition upon the shift from the neutral position to the drive position, the predetermined condition being configured to gradually change the target driving force through an annealing with a time constant, the Step (a) setting the target driving force based on the driving force demand as well as on the non-satisfaction of the predetermined condition regardless of whether or not the predetermined condition is satisfied when the setting of the limiting driving force by the limit driving force setting module is released; and

(b) controlling the internal combustion engine and the motor so as to ensure the total driving force is equivalent to the set target driving force.