Drive apparatus for hybrid vehicle

A drive apparatus for a hybrid vehicle, the drive apparatus comprising:

• (a) a hybrid drive unit including (a-1) an automatic transmission including a plurality of hydraulically-operated shifting engagement devices and configured to establish a plurality of gear positions depending on engaged/released states of the shifting engagement devices, (a-2) a first rotating machine, and (a-3) an engine connected to the first rotating machine through a hydraulically-operated connecting/disconnecting device such that the engine is disconnectable from the first rotating machine that is disposed in a power transmission path between the automatic transmission and the engine, and wherein the hybrid drive unit is configured to drive one of front and rear wheels of the hybrid vehicle through the automatic transmission, with the engine and the first rotating machine being used as running drive power sources;
• (b) an electric drive unit including a second rotating machine and configured to drive the other of the front and rear wheels, with the second rotating machine being used as a running drive power source;
• (c) a hydraulic control unit including a plurality of electromagnetic valves configured to switch the engaged/released states of the shifting engagement devices and an engaged/released state of the connecting/disconnecting device;
• and
• (d) a hybrid control device configured, in event of an anomaly that disables a shift control of the automatic transmission, to generate an electric power by causing the first rotating machine to be rotated by the engine and drive the hybrid vehicle to run by causing the second rotating machine of the electric drive unit to be operated with use of the generated electric power, in a state in which a power transmission through the automatic transmission is cut off and the connecting/disconnecting device is engaged,
• wherein the hydraulic control unit includes:
• (c-1) a failure-determination electromagnetic valve configured to switch an output state of a failure determination fluid in event of a power OFF failure by which supply of the electric power to all of the electromagnetic valves is cut off, and
• (c-2) a fail-safe valve including (c-2-i) a switch port to which the failure determination fluid is to be supplied, (c-2-ii) a connection port connected to a discharge fluid passage through which a working fluid is to be discharged from the connecting/disconnecting device so as to release the connecting/disconnecting device, (c-2-iii) a drain port through which the working fluid supplied to the connection port from the discharge fluid passage is to be drained, and (c-2-iv) an engagement port to which a failure-case engagement fluid is to be supplied for engaging the connecting/disconnecting device,
• wherein the fail-safe valve is to be switched between a normal-case connection state and a failure-case connection state, such that the connection port and the drain port are in communication with each other for draining the working fluid supplied from the discharge fluid passage when the fail-safe valve is placed in the normal-case connection state, and such that the connection port and the engagement port are in communication with each other for supplying the failure-case engagement fluid to the discharge fluid passage so as to engage the connecting/disconnecting device when the fail-safe valve is placed in the failure-case connection state, and
• wherein the fail-safe valve is normally placed in the normal-case connection state, and is switched from the normal-case connection state to the failure-case connection state when the output state of the failure determination fluid is switched in the event of the power OFF failure.

A drive apparatus for a hybrid vehicle, the drive apparatus comprising:

• (a) a hybrid drive unit including (a-1) an automatic transmission including a plurality of hydraulically-operated shifting engagement devices and configured to establish a plurality of gear positions depending on engaged/released states of the shifting engagement devices, (a-2) a first rotating machine, and (a-3) an engine connected to the first rotating machine through a hydraulically-operated connecting/disconnecting device such that the engine is disconnectable from the first rotating machine that is disposed in a power transmission path between the automatic transmission and the engine, and wherein the hybrid drive unit is configured to drive one of front and rear wheels of the hybrid vehicle through the automatic transmission, with the engine and the first rotating machine being used as running drive power sources;
• (b) an electric drive unit including a second rotating machine and configured to drive the other of the front and rear wheels, with the second rotating machine being used as a running drive power source;
• (c) a hydraulic control unit including a plurality of electromagnetic valves configured to switch the engaged/released states of the shifting engagement devices and an engaged/released state of the connecting/disconnecting device;
• and
• (d) a hybrid control device configured, in event of an anomaly that disables a shift control of the automatic transmission, to generate an electric power by causing the first rotating machine to be rotated by the engine and drive the hybrid vehicle to run by causing the second rotating machine of the electric drive unit to be operated with use of the generated electric power, in a state in which a power transmission through the automatic transmission is cut off and the connecting/disconnecting device is engaged,
• wherein the electromagnetic valves are provided for the respective shifting engagement devices in the hydraulic control unit, such that, when the electric power is supplied to each of the electromagnetic valves, a corresponding one of the shifting engagement devices is engaged by a working fluid that is supplied to the corresponding one of the shifting engagement devices from the each of the electromagnetic valves, and such that, when supply of the electric power to each of the electromagnetic valves is stopped, a corresponding one of the shifting engagement devices is released, and
• wherein the automatic transmission is placed in a power-transmission cut-off state with all of the shifting engagement devices being released, in the event of the anomaly that is a power OFF failure by which supply of the electric power to all of the electromagnetic valves is cut off.