Method to control execution of shift to lower gear while accelerator pedal is released

Abstract

The invention relates to method to control the execution of a shift to a lower gear while an accelerator pedal (22) is released in a drivetrain (6) provided with a dual-clutch, servo-assisted transmission (7); the control method comprises the following steps: opening, in a first instant (ti), an outgoing clutch (16A); closing, in the first instant (ti), an incoming clutch (16B); completing the opening of the outgoing clutch (16A) and the closing of the incoming clutch (16A) in a second instant (t2); synchronizing, between the second instant (t2) and a third instant (t3), a rotation speed ([omega]E) of the internal combustion engine (4) with a rotation speed ([omega]B) of the incoming clutch (16B); and controlling the incoming clutch (16B) between the second instant (t2) and the third instant (t3) so as to have the incoming clutch (16B) temporarily transmit a greater torque (TB) than the torque (TB) that the clutch (16B) is going to transmit immediately after the shift to a lower gear and than the torque (TA) that the outgoing clutch (16A) transmitted immediately before the shift to a lower gear.

Description

[0001] Cross References to Related Applications [0002] This patent application claims priority from Italian Patent Application No. 102019000017513, filed September 30, 2019, the entire disclosure of which is hereby incorporated by reference. technical field [0003] The present invention relates to controlling the execution of a shift to a lower gear while releasing the accelerator pedal (i.e., where the subsequent or incoming gear is lower than the preceding or exiting gear) in a powertrain having a dual-clutch servo-assisted transmission shift) method. Background technique [0004] A powertrain with a dual-clutch servo-assisted gearbox consists of: a pair of main shafts coaxial with each other, independent of each other and inserted into each other; two clutches coaxial, each designed to connect the corresponding main shaft to the internal combustion engine and at least one layshaft which transmits motion to the drive wheels and which may be coupled to the mainshaft by ...

AI Technical Summary

Problems solved by technology

However, in a standard shift of a dual-clutch transmission, the longitudinal deceleration of the road vehicle increases gradually (and thus almost imperceptibly) during the shift to the lower gear due to the progressive reduction of the gear ratio; from performance This shifting pattern is highly positive from the point of view of the driver, but it creates the exact opposite impression among most drivers, that of impairing performance

Images