Drive apparatus for hybrid vehicle

1. A drive apparatus for a hybrid vehicle,

the drive apparatus including:

an engine;

a first motor generator;

an output shaft for outputting drive power from drive wheels of the vehicle;

a second motor generator which transmits power to the output shaft;

a power split mechanism having a first rotational element, a second rotational element, and a third rotational element which are capable of differentially rotating with each other, the first rotational element being connected to the engine, and the second rotational element being connected to the first motor generator;

a clutch operating between an engaging state where the third rotational element of the power split mechanism and the output shaft are connected with each other and a release state where the third rotational element and the output shaft are separated from each other;

a lock mechanism operating between a lock state where the third rotational element of the power split mechanism is locked so as not to rotate and an unlocked state where the third rotational element locked is released; and

an electronic control unit controlling the engine, the first motor generator, the second motor generator, the clutch, and the lock mechanism, wherein

the electronic control unit is programmed so as to include rotating speed control programming instructions that are executed to control a rotating speed of the third rotational element before a control to the clutch or the lock mechanism is performed, and

the rotating speed control programming instructions are executed to control the rotating speed of the third rotational element by controlling the first motor generator after a rotating speed of the engine is deemed to be zero by executing an engine stop control for stopping the engine, when a condition which the control to the clutch or the lock mechanism is performed is satisfied while the engine is running.

2. The drive apparatus according to claim 1 , further including

a shift position selection device where plural shift positions including a parking position, a reverse position, a neutral position, and a drive position are set, the shift position selection device receiving a shift operation for selecting each shift position of the plural shift positions by a driver, and

the electronic control unit is further programmed so as to include shift control programming instructions that are executed to: control the lock mechanism to go into the lock state and control the clutch to go into the engaging state when the shift position selection device receives the shift operation for selecting the parking position; control the lock mechanism to go into the lock state and control the clutch to go into the release state when the shift position selection device receives the shift operation for selecting the reverse position; and control the lock mechanism to go into the unlocked state and control the clutch to go into the engaging state when the shift position selection device receives the shift operation for selecting the drive position.

3. The drive apparatus according to claim 2 , wherein

in a case that the reverse position is selected as the shift operation when the drive position or the parking position is in a state of selection while the engine is running,

the rotating speed control programming instructions are executed to determine that the condition is satisfied and execute a zero rotation control for reducing a rotating speed of the third rotational element so as to get close to zero by controlling the first motor generator after the rotating speed of the engine is deemed to be zero by executing the engine stop control, and

the shift control programming instructions are executed to control the lock mechanism to go into the lock state from the unlocked state, after the zero rotation control is ended.

4. The drive apparatus according to claim 2 , wherein

in a case that the drive position or the parking position is selected as the shift operation when the reverse position is in a state of selection while the engine is running,

the rotating speed control programming instructions are executed to determine that the condition is satisfied and execute a synchronization control for limiting a difference of rotating speed between elements which are connected with each other by the clutch within an allowable range by controlling the first motor generator after the rotating speed of the engine is deemed to be zero by executing the engine stop control, and

the shift control programming instructions are executed to control the clutch to go into the engaging state from the release state, after the synchronization control is ended.

5. The drive apparatus according to claim 2 , wherein

the clutch is configured as a dog clutch, and

in a case that the reverse position is selected as the shift operation when the parking position is in a state of selection while the engine is running, the shift control programming instructions are executed to control the lock mechanism to go into the unlocked state from the lock state before the engine stop control by the rotating speed control programming instructions.

6. The drive apparatus according to claim 2 , wherein

in a case that the neutral position is selected as the shift operation,

the rotating speed control programming instructions are executed to defer an execution of the engine stop control even though the engine is running, and

the shift control programming instructions are executed to keep a state of each of the lock mechanism and the clutch in a state corresponding to the shift position set before the neutral position selected.

7. The drive apparatus according to claim 1 , wherein

the clutch is configured as a dog clutch, and

the shift control programming instructions are executed to execute a torque reduction control for reducing torque which acts on the clutch by controlling the first motor generator before controlling the clutch to go into the release state from the engaging state.