Control of infinitely variable transmission
AssigneeNissan Motor Co., Ltd.
InventorsYasushi Narita, Yoshinori Iwasaki, Tatsuya Nagato
Life of this patent
Estimating the term…
Abstract
A controller (80) calculates a target speed ratio of a continuously variable transmission (2) incorporated into an infinitely variable transmission for a vehicle and a target vehicle acceleration based on a vehicle running state. When a predetermined creep torque control condition holds (S90-S93, S101), the controller (80) corrects the target speed ratio such that the deviation of the target acceleration from the real vehicle acceleration to decrease. By controlling the speed ratio of the continuously variable transmission to the corrected target speed ratio, the infinitely variable transmission generates a creep torque consistent with the driver's intention.
Claims13
A control device for an infinitely variable transmission for a vehicle, the infinitely variable transmission comprising an input shaft, a continuously variable transmission which outputs the rotation of the input shaft at an arbitrary speed ratio, a fixed speed ratio transmission which outputs the rotation of the input shaft at a fixed speed ratio, and an output shaft which changes a rotation direction and a rotation speed according to a difference between an output rotation speed of the continuously variable transmission and an output rotation speed of the fixed speed ratio transmission, the device comprising:
- a sensor which detects a running state of the vehicle;
- a sensor which detects a real vehicle acceleration;
- and
- a programmable controller programmed to:
- calculate a target speed ratio of the continuously variable transmission based on the running state of the vehicle;
- set a target vehicle acceleration based on the running state of the vehicle;
- calculate an acceleration deviation of the target vehicle acceleration from the real vehicle acceleration;
- determine if a predetermined creep torque control condition holds based on the running state of the vehicle;
- calculate a corrected target speed ratio, if the predetermined condition holds, to cause the acceleration deviation to decrease;
- and
- control the speed ratio of the continuously variable transmission based on the corrected target speed ratio.
A control device for an infinitely variable transmission for a vehicle, the infinitely variable transmission comprising an input shaft, a continuously variable transmission which outputs the rotation of the input shaft at an arbitrary speed ratio, a fixed speed ratio transmission which outputs the rotation of the input shaft at a fixed speed ratio, and an output shaft which changes a rotation direction and a rotation speed according to a difference between an output rotation speed of the continuously variable transmission and an output rotation speed of the fixed speed ratio transmission, the device comprising:
- means for detecting a running state of the vehicle;
- means for detecting a real vehicle acceleration;
- and
- means for calculating a target speed ratio of the continuously variable transmission based on the running state of the vehicle;
- means for setting a target vehicle acceleration based on the running state of the vehicle;
- means for calculating an acceleration deviation of the target vehicle acceleration from the real vehicle acceleration;
- means for determining if a predetermined creep torque control condition holds based on the running state of the vehicle;
- means for calculating a corrected target speed ratio, if the predetermined condition holds, to cause the acceleration deviation to decrease;
- and
- means for controlling the speed ratio of the continuously variable transmission based on the corrected target speed ratio.
A control method for an infinitely variable transmission for a vehicle, the infinitely variable transmission comprising an input shaft, a continuously variable transmission which outputs the rotation of the input shaft at an arbitrary speed ratio, a fixed speed ratio transmission which outputs the rotation of the input shaft at a fixed speed ratio, and an output shaft which changes a rotation direction and a rotation speed according to a difference between an output rotation speed of the continuously variable transmission and an output rotation speed of the fixed speed ratio transmission, the method comprising:
- detecting a running state of the vehicle;
- detecting a real vehicle acceleration;
- calculating a target speed ratio of the continuously variable transmission based on the running state of the vehicle;
- setting a target vehicle acceleration based on the running state of the vehicle;
- calculating an acceleration deviation of the target vehicle acceleration from the real vehicle acceleration;
- determining if a predetermined creep torque control condition holds based on the running state of the vehicle;
- calculating a corrected target speed ratio, if the predetermined condition holds, to cause the acceleration deviation to decrease;
- and
- controlling the speed ratio of the continuously variable transmission based on the corrected target speed ratio.
A control device for an infinitely variable transmission for a vehicle, the infinitely variable transmission comprising an input shaft, a continuously variable transmission which outputs the rotation of the input shaft at an arbitrary speed ratio, a fixed speed ratio transmission which outputs the rotation of the input shaft at a fixed speed ratio, and an output shaft which changes a rotation direction and a rotation speed according to a difference between an output rotation speed of the continuously variable transmission and an output rotation speed of the fixed speed ratio transmission, the device comprising:
- a sensor which detects a running state of the vehicle;
- a sensor which detects a real vehicle acceleration;
- and
- a programmable controller programmed to:
- calculate a target speed ratio of the continuously variable transmission based on the running state of the vehicle:
- set a target vehicle acceleration based on the running state of the vehicle;
- determine if a predetermined creep torque control condition holds based on the running state of the vehicle;
- calculate a corrected target speed ratio, if the predetermined condition holds, to cause a ratio of the rotation speed of the input shaft with respect to the rotation speed of the output shaft to become smaller as the target vehicle acceleration becomes larger;
- and
- control the speed ratio of the continuously variable transmission based on the corrected target speed ratio.
Dependencies are inferred from the claim text.