Drive torque control device, drive source unit and vehicle

1. A drive torque control device of a vehicle that includes

a drive source for generating a drive source torque,

a brake mechanism for generating a braking torque, and

a drive wheel for driving the vehicle,

the drive torque control device comprising:

a target drive wheel torque calculator configured to calculate a target drive wheel torque for driving the drive wheel;

a drive source torque control unit configured to

estimate a drive source torque limit value based on a revolution speed of the drive source and a throttle opening, the drive source torque limit value including a maximum value and a minimum value of the drive source torque that is generatable by the drive source in a predetermined period of time from a current time,

calculate a target drive source torque, which is a target value of the drive source torque to be generated in the predetermined period of time from the current time, based on the target drive wheel torque and the estimated drive source torque limit value, including

upon determining that the maximum value in the estimated drive source torque limit value is smaller than the target drive wheel torque and that the minimum value in the estimated drive source torque limit value is larger than the target drive wheel torque, limiting the target drive wheel torque calculated at the target drive wheel torque calculator by the maximum value and the minimum value, respectively, and

control the generation of the drive source torque by the drive source based on the target drive source torque; and

a braking torque control unit configured to

calculate a target braking torque, which is a target value of the braking torque to be generated by the brake mechanism in the predetermined period of time from the current time, based on the target drive wheel torque and the target drive source torque, and

control the generation of the braking torque by the brake mechanism based on the target braking torque.

2. The drive torque control device according to claim 1 , wherein the braking torque control unit is configured to

estimate a braking torque limit value, which includes at least one of a maximum value and a minimum value of the braking torque that is generatable by the brake mechanism in the predetermined period of time from the current time, and

calculate the target braking torque based on the target drive wheel torque, the target drive source torque and the braking torque limit value.

3. The drive torque control device according to claim 2 , wherein

the drive source torque control unit comprises:

a drive source torque controller configured to control the generation of the drive source torque based on the target drive source torque and to estimate the drive source torque limit value; and

a target drive source torque calculator configured to calculate the target drive source torque based on the target drive wheel torque and the drive source torque limit value; and

the braking torque control unit comprises:

a braking torque controller configured to control the generation of the braking torque based on the target braking torque and to estimate the braking torque limit value; and

a target braking torque calculator configured to calculate the target braking torque based on the target drive wheel torque, the target drive source torque and the braking torque limit value.

4. The drive torque control device according to claim 3 , wherein

the vehicle further includes a brake operating device; and

the target braking torque calculator calculates the target braking torque further based on an amount of operation of the brake operating device.

5. The drive torque control device according to claim 4 , wherein

the target braking torque calculator sets the target braking torque such that the target braking torque, which is calculated based on an amount of operation of the brake operating device, the target drive wheel torque and the target drive source torque, is smaller than a total value of the target braking torque, which is calculated based on the target drive wheel torque and the target drive source torque, and a required braking torque which corresponds to an amount of operation of the brake operating device.

6. The drive torque control device according to claim 3 , wherein the drive source torque controller

determines the drive source torque limit value based on the revolution speed of the drive source and the throttle opening; and

outputs the drive source torque limit to the target drive source torque calculator.

7. The drive torque control device according to claim 2 , wherein

upon determining that a difference between the target drive wheel torque and the target drive source torque is equal to or smaller than a predetermined value, the braking torque control unit sets the target braking torque to zero.

8. A drive source unit of a vehicle that includes

a brake mechanism for generating a braking torque, and

a drive wheel for driving the vehicle,

the drive source unit comprising:

a drive source for generating a drive source torque,

a drive torque control device that includes

a target drive wheel torque calculator configured to calculate a target drive wheel torque for driving the drive wheel;

a drive source torque control unit configured to

estimate a drive source torque limit value based on a revolution speed of the drive source and a throttle opening, the drive source torque limit value including a maximum value and a minimum value of the drive source torque that is generatable by the drive source in a predetermined period of time from a current time,

calculate a target drive source torque, which is a target value of the drive source torque to be generated in the predetermined period of time from the current time, based on the target drive wheel torque and the estimated drive source torque limit value, including

upon determining that the maximum value in the estimated drive source torque limit value is smaller than the target drive wheel torque and that the minimum value in the estimated drive source torque limit value is larger than the target drive wheel torque, limiting the target drive wheel torque calculated at the target drive wheel torque calculator by the maximum value and the minimum value, respectively, and

control the generation of the drive source torque by the drive source based on the target drive source torque; and

a braking torque control unit configured to

calculate a target braking torque, which is a target value of the braking torque to be generated by the brake mechanism in the predetermined period of time from the current time, based on the target drive wheel torque and the target drive source torque, and

control the generation of the braking torque by the brake mechanism based on the target braking torque;

an air inlet passage configured to supply air to the drive source;

a throttle valve disposed in the air inlet passage and configured to change a cross-sectional area of the air inlet passage; and

an air cleaner configured to allow passage of air into the air inlet passage.

9. The drive source unit according to claim 8 , comprising further:

a throttle valve drive unit configured to change the cross-sectional area of the air inlet passage by driving the throttle valve, wherein

the drive source torque control unit is configured to control driving of the throttle valve drive unit.

10. The drive source unit according to claim 9 , wherein

the air inlet passage has a first end portion and a second end portion that are respectively connected to the drive source and the air cleaner; and

the throttle valve is disposed in a position that is closer to the first end portion of the air inlet passage than the second end portion.

11. A vehicle, comprising:

a drive source configured to generate a drive source torque;

a drive wheel configured to be driven by the drive source;

a brake mechanism configured to apply braking torque to the drive wheel; and

a drive torque control device including

a target drive wheel torque calculator configured to calculate a target drive wheel torque for driving the drive wheel;

a drive source torque control unit configured to

estimate a drive source torque limit value based on a revolution speed of the drive source and a throttle opening, the drive source torque limit value including a maximum value and a minimum value of the drive source torque that is generatable by the drive source in a predetermined period of time from a current time,

calculate a target drive source torque, which is a target value of the drive source torque to be generated in the predetermined period of time from the current time, based on the target drive wheel torque and the estimated drive source torque limit value, including

upon determining that the maximum value in the estimated drive source torque limit value is smaller than the target drive wheel torque and that the minimum value in the estimated drive source torque limit value is larger than the target drive wheel torque, limiting the target drive wheel torque calculated at the target drive wheel torque calculator by the maximum value and the minimum value, respectively, and

control the generation of the drive source torque by the drive source based on the target drive source torque; and

a braking torque control unit configured to

calculate a target braking torque, which is a target value of the braking torque to be generated by the brake mechanism in the predetermined period of time from the current time, based on the target drive wheel torque and the target drive source torque, and

control the generation of the braking torque by the brake mechanism based on the target braking torque.

12. The vehicle according to claim 11 , further comprising a riding type seat.