Driving force control system and saddled vehicle

1. A driving force control system comprising:

an absolute bank angle detector which detects an absolute bank angle that is an absolute value of a vehicle's bank angle, the absolute bank angle having a maximum value at which the absolute bank angle that has been rising starts to fall;

a calculation circuit which calculates a relative bank angle that is an angle measured between the detected absolute bank angle and a maximum absolute bank angle, the maximum absolute bank angle being the maximum value of the absolute bank angle; and

a controller which controls a driving force of the vehicle based on the relative bank angle.

2. The driving force control system of claim 1 , wherein the controller changes an accelerator-throttle characteristic, representing how a throttle position angle of a throttle of the vehicle changes with an accelerator position angle of an accelerator of the vehicle, according to the relative bank angle.

3. The driving force control system of claim 2 , wherein the controller is responsive to the relative bank angle being small, so that the controller controls the driving force based on the accelerator-throttle characteristic such that a ratio, between a change of the throttle position angle with respect to a change in the accelerator position angle, is smaller than when the relative bank angle is large.

4. The driving force control system of claim 2 , wherein as the relative bank angle increases, the controller modifies the accelerator-throttle characteristic so that a ratio, between a change of the throttle position angle with respect to a change in the accelerator position angle, becomes larger.

5. The driving force control system of claim 2 , wherein the controller is responsive to the relative bank angle being small, so that the controller controls the driving force based on the accelerator-throttle characteristic such that a ratio, between the throttle position angle with respect to the accelerator position angle, is smaller than when the relative bank angle is large.

6. The driving force control system of claim 2 , wherein as the relative bank angle increases, the controller modifies the accelerator-throttle characteristic so that a ratio, between the throttle position angle with respect to the accelerator position angle, becomes larger.

7. The driving force control system of claim 1 , wherein the calculation circuit starts detecting for the maximum absolute bank angle after the vehicle's front wheel speed has decreased.

8. The driving force control system of claim 1 , wherein the calculation circuit starts detecting for the maximum absolute bank angle in response to an accelerator position angle of an accelerator of the vehicle being equal to or smaller than a predetermined value.

9. The driving force control system of claim 1 , wherein the calculation circuit starts detecting for the maximum absolute bank angle in response to the absolute bank angle being equal to or smaller than a predetermined value.

10. The driving force control system of claim 2 , wherein the controller is responsive so that upon determining that the detected absolute bank angle has become equal to or greater than a predetermined value, the controller starts controlling the driving force by changing the accelerator-throttle characteristic.

11. The driving force control system of claim 2 , wherein the controller is responsive so that upon sensing that the accelerator position angle has become equal to or greater than a predetermined value, the controller starts controlling the driving force by changing the accelerator-throttle characteristic.

12. The driving force control system of claim 2 , wherein the controller is responsive so that upon sensing that a torque of the vehicle's driving source has become equal to or greater than a predetermined value, the controller starts controlling the driving force to change the accelerator-throttle characteristic.

13. The driving force control system of claim 1 , further comprising a traction control for further controlling the driving force, wherein the controller changes a threshold slip value, at which the traction control is turned ON and OFF, according to the relative bank angle.

14. The driving force control system of claim 13 , wherein the controller is responsive to the relative bank angle being small, so that the controller decreases the threshold slip value, compared to when the relative bank angle is large.

15. The driving force control system of claim 1 , wherein the controller reduces the driving force further through a traction control to a varying degree according to the relative bank angle.

16. The driving force control system of claim 15 , wherein the controller is responsive to the relative bank angle being small, so that the controller reduces the driving force more significantly than when the relative bank angle is large.

17. A saddled vehicle comprising the driving force control system of claim 1 .

18. The driving force control system of claim 1 , wherein the calculation circuit starts detecting the maximum value of the absolute bank angle after the vehicle's front wheel speed has decreased to be equal to or less than a predetermined value.

19. A non-transitory computer readable medium storing a computer program which is defined to make a computer control a saddled vehicle's driving force, the program being defined to make the computer perform the steps of:

detecting an absolute bank angle that is an absolute value of the saddled vehicle's bank angle, the absolute bank angle having a maximum value at which the absolute bank angle that has been rising starts to fall;

calculating a relative bank angle that is an angle measured between the detected absolute bank angle and a maximum absolute bank angle, the maximum absolute bank angle being the maximum value of the absolute bank angle; and

controlling the driving force based on the relative bank angle.

20. A driving force control system comprising:

an absolute bank angle detector programmed to detects an absolute bank angle that is an absolute value of a vehicle's bank angle, the absolute bank angle having a maximum value at which the absolute bank angle that has been rising starts to fall;

a calculation circuit programmed to calculate a relative bank angle that is an angle measured between the detected absolute bank angle and a maximum absolute bank angle, the maximum absolute bank angle being the maximum value of the absolute bank angle; and

a controller programmed to control a driving force of the vehicle based on the relative bank angle.