Method for operating a hybrid drive train of a motor vehicle

• US 20080189018A1
• Filed: 02/15/2008
• Published: 08/07/2008
• Est. Priority Date: 08/20/2005
• Status: Active Grant

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler AG (Mercedes-Benz Group AG)
• Inventors: Riedl, Klaus, Lang, Jurgen
• Granted Patent: US 8,352,135 B2
• Time in Patent Office: Days
• US Class Current: 701/54
• CPC Class Codes: B60K 6/387 Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 15/2054 by controlling transmissions or clutches
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/486 Operating parameters
• CPC Class Codes: B60L 2240/507 Operating parameters
• CPC Class Codes: B60L 3/0023 Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
• CPC Class Codes: B60L 3/0076 relating to braking
• CPC Class Codes: B60L 3/0092 with use of redundant elements for safety purposes
• CPC Class Codes: B60L 7/26 Controlling the braking effect
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: F16H 2200/0056 the gear ratios comprising seven forward speeds
• CPC Class Codes: F16H 2200/2048 with seven engaging means
• CPC Class Codes: F16H 2200/2097 comprising an orbital gear set member permanently connected to the housing, e.g. a sun wheel permanently connected to the housing
• CPC Class Codes: F16H 3/663 with conveying rotary motion between axially spaced orbital gears, e.g. RAVIGNEAUX
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

In a method of operating a hybrid drive train for a motor vehicle including an internal combustion engine, an electric machine and a transmission, a first clutch arranged between the internal combustion engine and the transmission and the electric machine being arranged in parallel with the first clutch and being connectable to the internal combustion engine by way of a second clutch and to the transmission via a third clutch, the electric machine is connected by means of the second and third clutches to the internal combustion engine and to the transmission for assisting the first clutch transmitting an excessive engine torque, and upon failure of the first clutch, for starting movement of the motor vehicle, the third clutch is engaged and the electric machine is energized for transferring an electric machine torque to the transmission and the second clutch is engaged when the vehicle has reached a speed corresponding to the engine speed.

Claims

1. A method for operating a hybrid drive train of a motor vehicle, said drive train including

an internal combustion engine (11),

a transmission (15, 115),

a first clutch (NAK) arranged between the internal combustion engine (11) and the transmission (15, 115),

an electric machine (28),

means for connecting the electric machine to the drive train including a second clutch (KM) for connecting the electric machine to the internal combustion engine (11) without the interposition of the first clutch (NAK), and

a third clutch (KE) for connecting the electric machine to the transmission (15, 115) without the interposition of the first clutch (NAK),

said method comprising the steps of:

transmitting selectively a part of the torque of the internal combustion engine (11) via the second clutch (KM), the electric machine (28) and the third clutch (KE) to the transmission (15, 115), in order to assist the first clutch (NAK) or

in the event of a fault being detected in the first clutch (NAK) in the driving mode,

connecting the electric machine (28) by means of the second clutch (KM) to the internal combustion engine (11) and by means of the third clutch (KE) to the transmission (15, 115).

2. The method as claimed in claim 1, wherein, in the event of a fault being detected in the first clutch (NAK), transmitting a torque for starting out movement of the motor vehicle, connecting the electric machine (28) by means of the third clutch (KE) to the transmission (15, 115), energizing the electric machine to accelerate the vehicle while keeping the second clutch (KM) disengaged from the internal combustion engine, and engaging the second clutch (KM) when the vehicle has reached a speed corresponding to the momentary engine speed for transmitting engine power to the transmission.