Patent ID: 7219757

Claim:
A mode transfer control apparatus for a hybrid vehicle, comprising: power sources including an engine and at least one motor; a differential gear transmission including a planetary gear train in which the respective power sources are linked with revolutional elements of the planetary gear train and at least one engagement element that is engaged to achieve a fixed transmission gear ratio from a state in which the engagement element is released to provide a continuously variable transmission function for the planetary gear train; a mode selecting section that selects one steady-state mode from modes of a continuously variable transmission gear ratio in which the engagement element is released and a fixed transmission gear ratio in which the engagement element is engaged; an engagement element controlling section that performs an engagement-and-release control for the engagement element during a mode transfer between the continuously variable transmission gear ratio mode and the fixed transmission gear ratio mode; a vehicle speed detecting section that detects a vehicle speed; a target driving force calculating section that calculates a target driving force of the vehicle; and a mode area map setting section that sets, according to the vehicle speed and the target driving force, a steady-state area map including a continuously variable transmission gear ratio mode area, a fixed transmission gear ratio mode area, and an overlap area in which both of the continuously variable transmission gear ratio mode area and the fixed transmission gear ratio mode area are overlapped with each other, the mode selecting section, in a state in which the vehicle is in at least one of a start state and a travel state and in one steady-state mode of the continuously variable transmission gear ratio mode and the fixed transmission gear ratio mode, inhibiting a mode transfer to the other steady-state mode of the continuously variable transmission gear ratio mode and the fixed transmission gear ratio mode in a case where a driving point of the vehicle determined according to a detection value of the vehicle speed and a calculation value of the target driving force is present within the overlap area in the steady-state mode area map in which both of the continuously variable transmission gear ratio mode and the fixed transmission gear ratio mode are selectable.