Control method of hybrid vehicle

摘要

A hybrid vehicle includes an internal-combustion engine, an engine starter ISG motor, a main motor that drives rear wheels, a CVT pulley belt disposed between an engine output shaft and a front wheel shaft, a clutch connected between the output shaft of the internal-combustion engine and an input shaft of the CVT, a battery, and a hybrid controller. When the hybrid controller determines that there is a need to add a traction force of the engine from a state where the vehicle is driven by the main motor alone, the hybrid controller controls the respective components so as to start the engine by the ISG motor in a state where the clutch is disengaged, control a speed ratio of the CVT so that a CVT input speed achieves a target speed for starting clutch engagement, detects the engine rotation speed, detects the CVT input speed, and engages the clutch when a difference between those speeds falls within a predetermined range.

主权项

1. A control method for a hybrid vehicle in which the hybrid vehicle includes an internal-combustion engine, a traction motor that electrically drives the hybrid vehicle, a continuous variable transmission provided between an output shaft of the internal-combustion engine and an axle of first drive wheels, a clutch provided between the output shaft of the internal-combustion engine and an input shaft of the continuous variable transmission, and a starter motor connected coaxially to the output shaft of the internal combustion engine, the method comprising the steps of:
determining whether there is a need to add a traction force of the internal-combustion engine from a state where the vehicle is driven by the traction motor alone; starting the internal-combustion engine using a torque of the starter motor in a state where the clutch is disengaged when it is determined that there is a need to add the traction force of the internal-combustion engine, subsequently increasing a torque of the internal-combustion engine, and controlling a speed ratio of the continuous variable transmission so that a rotation speed of the input shaft of the continuous variable transmission achieves a target speed for starting clutch engagement; detecting a rotation speed of the output shaft of the internal-combustion engine; detecting the rotation speed of the input shaft of the continuous variable transmission; applying a negative torque of the starter motor to the internal-combustion engine to suppress a climb in the speed of the internal-combustion engine and switching the controlling the speed ratio of the continuous variable transmission from the achieving the target speed to increasing the rotation speed of the input shaft of the continuous variable transmission beyond the target speed, when the detected rotation speed of the output shaft of the internal-combustion engine becomes as high as or higher than the detected rotation speed of the input shaft of the continuous variable transmission; and operating the clutch to be engaged.