Method and system for controlling a vehicle powertrain

摘要

A method and system for controlling a powertrain in a vehicle includes steps including registering a road condition. If the registered road condition corresponds to normal road conditions then a first gear selection control algorithm is used intended for driving the vehicle in a normal mode corresponding to the conditions on an ordinary road. If the registered road condition corresponds to soft surface road conditions then a second gear selection control algorithm is used intended for driving the vehicle in a soft surface mode corresponding to the conditions on an soft surface road. In this way, a vehicle can be adapted to be provided with an AMT to work in a satisfactorily way under an increased diversity of conditions.

主权项

1. A powertrain system for a vehicle comprising
an automated master clutch; a stepped gearbox; the master clutch being configured to control driving torque from an engine to an input shaft of the stepped gearbox; the stepped gearbox comprising a plurality of gear wheel pairs providing multiple fixed gear staves that are obtainable by a plurality of axially displaceable engaging sleeves; and a control unit adapted to control the master clutch and the stepped gearbox,
the control unit being programmed to generate a control signal indicating a desired gear selection,the control unit comprising at least two different sets of gear selection control algorithms for generating the gear selection control signal, the control algorithms comprising engine rotational speed limits for when to upshift or downshift and for which gear to select and engage, the different gear selection control algorithms generating different gear selection control signals based on input data,the control unit further being connected to a gear selection control algorithm selector which indicates which gear selection control algorithm of the different control algorithms is to be used by the control unit, the different gear selection control algorithms comprising at least a first gear selection control algorithm in which the control unit sends signals for shifting gears in the stepped gearbox when driving the vehicle in a normal mode corresponding to the conditions on an ordinary road, and at least a second gear selection control algorithm in which the control unit sends signals for shifting gears in the stepped gearbox when driving the vehicle in a surface mode, the second gear control algorithm being arranged to provide a higher vehicle driving force than the first gear selection control algorithm,wherein the control unit is programmed to register input data including at least prevailing travel resistance and traction wheel slip, and where if the travel resistance is higher than a predetermined value and if the traction wheel slip is higher than another predetermined value, the control unit is programmed to generate control signals to control according to the second gear selection control algorithm.