Control apparatus for vehicle drive system

• US 8,342,273 B2
• Filed: 05/12/2010
• Issued: 01/01/2013
• Est. Priority Date: 05/14/2009
• Status: Active Grant

• Current Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: DENSO Corporation, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Takahashi, Shigenori
• Primary Examiner(s): Rocca, Joseph
• Assistant Examiner(s): ENGLISH, JAMES A
• Application Number:
  US12/778,451
• Publication Number:
  US 20100292881A1
• Time in Patent Office: 965 Days
• Field of Search: 701/22, 701/29.2, 180/65.275, 180/65.285, 180/65.28
• US Class Current: 180/65.28
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60W 20/50 Control strategies for responding to system failures, e.g. for fault diagnosis, failsafe operation or limp mode
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

Over rotation limitation control is performed to control an engine rotation speed so that a rotation speed of a pinion gear of a planetary gear set will not exceed a limit value, when a travel mode is changed to a limp-home travel mode in response to an abnormality in an inverter for a first motor generator. With this over rotation limitation control, a difference between rotation speeds of a ring gear coupled to a wheel side and a carrier coupled to an engine side. Thus, when the limp-home travel mode is performed due to the abnormality in the inverter for the first motor generator, a secondary failure, in which the pinion gear burns out and the planetary gear set fails, is prevented.

Claims

1. A control apparatus for a vehicle drive system, in which an internal combustion engine is coupled to a pinion gear of a planetary gear set through a carrier, a first motor generator is coupled to sun gear of the planetary gear set and a wheel drive shaft is coupled to a ring gear of the planetary gear set and a second motor generator is coupled to the wheel drive shaft, the control apparatus comprising:

a limp-home travel control section configured to change a vehicle operation mode to a limp-home travel mode, in which a vehicle is driven by only drive power of the second motor generator, when a predetermined abnormality occurs; and

an over rotation limitation control section configured to perform, when the vehicle operation mode is changed to the limp-home travel mode due to occurrence of abnormality in a system of the first motor generator, an over rotation limitation control to control a rotation speed of the internal combustion engine so that a difference between a rotation speed of the carrier and a rotation speed of the ring gear is limited to be within a predetermined range and a rotation speed of the pinion gear is limited to be lower than a predetermined limit value.

2. The control apparatus for a vehicle drive system according to claim 1, wherein the over rotation control limitation control section is further configured to set a target rotation speed of the internal combustion engine in accordance with a travel speed of the vehicle in performing the over rotation limitation control.

3. The control apparatus for a vehicle drive system according to claim 1, wherein the over rotation limitation control section is further configured to perform the over rotation limitation control only when the travel speed of the vehicle is higher than a predetermined value.

4. The control apparatus for a vehicle drive system according to claim 1, wherein:

at least the first motor generator and the planetary gear set are integrated unitarily into a transfer assembly unit; and

the over rotation limitation control section is further configured to perform the over rotation limitation control when the vehicle operation mode is changed to the limp-home travel mode due to occurrence of abnormality in an inverter for the first motor generator.

5. A control apparatus for a vehicle drive system, in which an internal combustion engine is coupled to a pinion gear of a planetary gear set through a carrier, a first motor generator is coupled to sun gear of the planetary gear set and a wheel drive shaft is coupled to a ring gear of the planetary gear set and a second motor generator is coupled to the wheel drive shaft, the control apparatus comprising:

a limp-home travel control section configured to change a vehicle operation mode to a limp-home travel mode, in which a vehicle is driven by drive power of the second motor generator, when a predetermined abnormality occurs; and

an over rotation limitation control section configured to perform, when the vehicle operation mode is changed to the limp-home travel mode, an over rotation limitation control to lower a travel speed of the vehicle so that a difference between a rotation speed of the carrier and a rotation speed of the ring gear is limited to be within a predetermined range and a rotation speed of the pinion gear is limited to be lower than a predetermined limit value.

6. The control apparatus for a vehicle drive system according to claim 5, wherein the over rotation limitation control section is further configured to lower the travel speed of the vehicle in performing the over rotation limitation control by a brake device provided in the vehicle.

7. The control apparatus for a vehicle drive system according to claim 5, wherein the over rotation limitation control section is further configured to lower the travel speed of the vehicle in performing the over rotation limitation control by a regenerative braking, in which kinetic energy of the vehicle is converted into electric power by the second MG and the electric power is restored to a battery.

8. The control apparatus for a vehicle drive system according to claim 5, wherein the over rotation limitation control section is further configured to perform the over rotation limitation control only when the travel speed of the vehicle is higher than a predetermined value.

9. The control apparatus for a vehicle drive system according to claim 5, wherein:

at least the first motor generator and the planetary gear set are integrated unitarily into a transfer assembly unit; and

the over rotation limitation control section is further configured to perform the over rotation limitation control when the vehicle operation mode is changed to the limp-home travel mode due to occurrence of abnormality in an inverter for the first motor generator.