1. Field of the Invention
The invention relates to a vehicular drive control apparatus and a method for controlling a vehicular drive apparatus. More particularly, the invention relates to a vehicular drive control apparatus which is provided with a first transmitting portion and a second transmitting portion, and reduces shift shock when a shift is performed in the first transmitting portion at the same time that a shift is performed in the second transmitting portion. The invention also relates to a method for controlling a vehicular drive apparatus provided with a first transmitting portion and a second transmitting portion, which reduces shift shock when a shift is performed in the first transmitting portion at the same time that a shift is performed in the second transmitting portion.
2. Description of the Related Art
Japanese Patent Application Publication No. 2005-337491 (JP-A-2005-337491) describes a vehicular drive apparatus in which an internal combustion engine, a first transmitting portion, a second transmitting portion, and driving wheels are connected in series. According to the clutch and brake application chart shown in FIG. 2 of JP-A-2005-337491, in a control apparatus of that vehicular drive apparatus there is no shift pattern in which the first transmitting portion and the second transmitting portion are shifted simultaneously in a normal shift operation. For example, in FIG. 2 of JP-A-2005-337491, during a shift from 4th gear to 5th gear, a shift is performed in the first transmitting portion but not in the second transmitting portion at that time. However, although not common knowledge, a shift pattern in which the first transmitting portion and the second transmitting portion are shifted simultaneously is conceivable depending on the structure of the planetary gear sets of the first and second transmitting portions.
Typically, when a shift is performed in an automatic transmission, shift shock occurs at the end of the shift, i.e., at the end of an inertia phase when the input rotation speed of the automatic transmission changes. Therefore, when a control apparatus of a vehicular drive apparatus has a shift pattern in which the first transmitting portion and the second transmitting portion are shifted at the same time, and the first and second transmitting portions are shifted at the same time and those shifts end at the same time, it is likely that an occupant will feel significant shift shock such that comfort is lost. However, the control apparatus of the vehicular drive apparatus described in JP-A-2005-337491 does not have a shift pattern in which the first transmitting portion and the second transmitting portion are shifted at the same time. Therefore there is no mention in JP-A-2005-337491 of control to reduce the potential discomfort due to significant shift shock being felt by an occupant as a result of shifts in the first and second transmitting portions ending at the same time.