Method to control the execution of a shift to a lower gear while an accelerator pedal is released in a drivetrain provided with a dual-clutch, servo-assisted transmission

Patent metadata

Field	Value
Publication number	US-11274743-B2
Application number	US-202017017236-A
Country	US
Kind code	B2
Filing date	Sep 10, 2020
Priority date	Sep 30, 2019
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A method to control the execution of a shift to a lower gear while an accelerator pedal is released in a drivetrain provided with a dual-clutch, servo-assisted transmission; the control method comprises the following steps: opening, in a first instant, an outgoing clutch; closing, in the first instant, an incoming clutch; completing the opening of the outgoing clutch and the closing of the incoming clutch in a second instant; synchronizing, between the second instant and a third instant, a rotation speed of the internal combustion engine with a rotation speed of the incoming clutch; and controlling the incoming clutch between the second instant and the third instant so as to have the incoming clutch temporarily transmit a greater torque than the torque that the clutch is going to transmit immediately after the shift to a lower gear and than the torque that the outgoing clutch transmitted immediately before the shift to a lower gear.

First claim

The invention claimed is:

1. A 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 ), so as to shift from a current gear (A) to a following gear (B), which is shorter than the current gear (A);
the drivetrain ( 6 ) comprises a dual-clutch, servo-assisted transmission ( 7 ) having two primary shafts ( 15 ); at least one secondary shaft ( 17 ) connected to drive wheels ( 3 ); and two clutches ( 16 A, 16 B), each interposed between a drive shaft ( 5 ) of an internal combustion engine ( 4 ) and a corresponding primary shaft ( 15 );
the control method comprises the steps of:
opening, in a first instant (t 1 ), an outgoing clutch ( 16 A) associated with the current gear (A);
closing, in the first instant (t 1 ), an incoming clutch ( 16 B) associated with the following gear (B);
completing the opening of the outgoing clutch ( 16 A) in a second instant (t 2 );
completing the closing of the incoming clutch ( 16 A) in the second instant (t 2 );
synchronizing, between the second instant (t 2 ) and a third instant (t 3 ), a rotation speed (ω E ) of the internal combustion engine ( 4 ) with a rotation speed (ω B ) of the incoming clutch ( 16 B), namely with the rotation speed (ω B ) imposed by the gear ratio of the following gear (B);
controlling the incoming clutch ( 16 B) between the second instant (t 2 ) and the third instant (t 3 ) so as to have the incoming clutch ( 16 B) temporarily transmit a greater torque (T B ) than the torque that the clutch ( 16 B) is going to transmit immediately after the shift to a lower gear and than the torque (T A ) that the outgoing clutch ( 16 A) transmitted immediately before the shift to a lower gear in order to accelerate the internal combustion engine ( 4 ) using the kinetic energy owned by a road vehicle ( 1 ) provided with the drivetrain ( 6 ); and
activating the internal combustion engine ( 4 ) so as to generate a torque (T E ) between the first instant (t 1 ) and a fourth instant (t 4 ), which is prior to the third instant (t 3 );
wherein a longitudinal deceleration (α) of the road vehicle ( 1 ) at first increases and then decreases between the first instant (t 1 ) and the third instant (t 3 ).

2. The control method according to claim 1 , wherein the fourth instant (t 4 ) is comprised between the second instant (t 2 ) and the third instant (t 3 ), namely the fourth instant (t 4 ) is subsequent to the second instant (t 2 ) and prior to the third instant (t 3 ).

3. The control method according to claim 2 , wherein the fourth instant (t 4 ) is closer to the second instant (t 2 ) and farther from the third instant (t 3 ).

4. The control method according to claim 1 , wherein the fourth instant (t 4 ) is prior to the second instant (t 2 ).

5. The control method according to claim 1 , wherein a longitudinal deceleration (α) of the road vehicle ( 1 ) decreases after the second instant (t 2 ).

6. The control method according to claim 1 , wherein the longitudinal deceleration (α) of the road vehicle ( 1 ) is zero in the second instant (t 2 ).

7. The control method according to claim 1 , wherein in the second instant (t 2 ) the road vehicle ( 1 ) has a positive longitudinal acceleration (α).

8. A 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 ), so as to shift from a current gear (A) to a following gear (B), which is shorter than the current gear (A);
the drivetrain ( 6 ) comprises a dual-clutch, servo-assisted transmission ( 7 ) having two primary shafts ( 15 ); at least one secondary shaft ( 17 ) connected to drive wheels ( 3 ); and two clutches ( 16 A, 16 B), each interposed between a drive shaft ( 5 ) of an internal combustion engine ( 4 ) and a corresponding primary shaft ( 15 );
the control method comprises the steps of:
opening, in a first instant (t 1 ), an outgoing clutch ( 16 A) associated with the current gear (A);
closing, in the first instant (t 1 ), an incoming clutch ( 16 B) associated with the following gear (B);
completing the opening of the outgoing clutch ( 16 A) in a second instant (t 2 );
completing the closing of the incoming clutch ( 16 A) in the second instant (t 2 );
synchronizing, between the second instant (t 2 ) and a third instant (t 3 ), a rotation speed (ω E ) of the internal combustion engine ( 4 ) with a rotation speed (ω B ) of the incoming clutch ( 16 B), namely with the rotation speed (ω B ) imposed by the gear ratio of the following gear (B);
controlling the incoming clutch ( 16 B) between the second instant (t 2 ) and the third instant (t 3 ) so as to have the incoming clutch ( 16 B) temporarily transmit a greater torque (T B ) than the torque that the clutch ( 16 B) is going to transmit immediately after the shift to a lower gear and than the torque (T A ) that the outgoing clutch ( 16 A) transmitted immediately before the shift to a lower gear in order to accelerate the internal combustion engine ( 4 ) using the kinetic energy owned by a road vehicle ( 1 ) provided with the drivetrain ( 6 ); and
activating the internal combustion engine ( 4 ) so as to generate a torque (T E ) between the first instant (t 1 ) and a fourth instant (t 4 ), which is prior to the third instant (t 3 );
wherein the fourth instant (t 4 ) is comprised between the second instant (t 2 ) and the third instant (t 3 ), namely the fourth instant (t 4 ) is subsequent to the second instant (t 2 ) and prior to the third instant (t 3 ); and
wherein the fourth instant (t 4 ) is closer to the second instant (t 2 ) and farther from the third instant (t 3 ).

9. A 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 ), so as to shift from a current gear (A) to a following gear (B), which is shorter than the current gear (A);
the drivetrain ( 6 ) comprises a dual-clutch, servo-assisted transmission ( 7 ) having two primary shafts ( 15 ); at least one secondary shaft ( 17 ) connected to drive wheels ( 3 ); and two clutches ( 16 A, 16 B), each interposed between a drive shaft ( 5 ) of an internal combustion engine ( 4 ) and a corresponding primary shaft ( 15 );
the control method comprises the steps of:
opening, in a first instant (t 1 ), an outgoing clutch ( 16 A) associated with the current gear (A);
closing, in the first instant (t 1 ), an incoming clutch ( 16 B) associated with the following gear (B);
completing the opening of the outgoing clutch ( 16 A) in a second instant (t 2 );
completing the closing of the incoming clutch ( 16 A) in the second instant (t 2 );
synchronizing, between the second instant (t 2 ) and a third instant (t 3 ), a rotation speed (ω E ) of the internal combustion engine ( 4 ) with a rotation speed (ω B ) of the incoming clutch ( 16 B), namely with the rotation speed (ω B ) imposed by the gear ratio of the following gear (B);
controlling the incoming clutch ( 16 B) between the second instant (t 2 ) and the third instant (t 3 ) so as to have the incoming clutch ( 16 B) temporarily transmit a greater torque (T B ) than the torque that the clutch ( 16 B) is going to transmit immediately after the shift to a lower gear and than the torque (T A ) that the outgoing clutch ( 16 A) transmitted immediately before the shift to a lower gear in order to accelerate the internal combustion engine ( 4 ) using the kinetic energy owned by a road vehicle ( 1 ) provided with the drivetrain ( 6 ); and
activating the internal combustion engine ( 4 ) so as to generate a torque (T

Assignees

• Ferrari Spa

Inventors

• Barone Alessandro
• Nannini Andrea
• Senserini Giacomo
• Marconi Stefano

Classifications

• F16H61/0403 Primary

  Synchronisation before shifting · CPC title

• F16H61/21

  Providing engine brake control · CPC title

• F16H63/50

  Signals to an engine or motor · CPC title

• F16H61/0204

  for gearshift control, e.g. control functions for performing shifting or generation of shift signal · CPC title

• F16H61/18

  Preventing unintentional or unsafe shift {, e.g. preventing manual shift from highest gear to reverse gear} · CPC title