Method to control a road vehicle provided with a dual-clutch, servo-assisted transmission and standing still with the internal combustion engine turned on

Patent metadata

Field	Value
Publication number	US-11173908-B2
Application number	US-202017015351-A
Country	US
Kind code	B2
Filing date	Sep 9, 2020
Priority date	Sep 30, 2019
Publication date	Nov 16, 2021
Grant date	Nov 16, 2021

Abstract

A method to control a road vehicle provided with a dual-clutch, servo-assisted transmission and standing still with the internal combustion engine turned on; the control method generally includes, when the road vehicle is standing still with the internal combustion engine turned on, the steps of: engaging a forward gear associated with a first clutch; engaging a reverse gear associated with a second clutch, which is different from and independent of the first clutch; closing the first clutch so as to cause the first clutch to transmit a first torque; and closing the second clutch so as to cause the second clutch to transmit a second torque, which is equal to the first torque multiplied by the quotient between a gear ratio of the reverse gear and a gear ratio of the forward gear.

First claim

The invention claimed is:

1. A method to control a road vehicle ( 1 ) provided with a dual-clutch, servo-assisted transmission ( 7 ) and standing still with an internal combustion engine ( 4 ) turned on; the control method comprises, when the road vehicle ( 1 ) is standing still with the internal combustion engine ( 4 ) turned on, the steps of:
engaging a forward gear associated with a first clutch ( 16 A);
engaging a reverse gear (R) associated with a second clutch ( 16 B), which is different from and independent of the first clutch ( 16 A);
closing the first clutch ( 16 A) so as to cause the first clutch ( 16 A) to transmit a first torque (T A );
closing the second clutch ( 16 B) so as to cause the second clutch ( 16 B) to transmit a second torque (T B ), which is equal to the first torque (T A ) multiplied by the quotient between a gear ratio of the reverse gear (R) and a gear ratio of the forward gear;
detecting a rotation speed (ω 2 ) of a secondary shaft ( 17 ) of the transmission ( 7 ); and
modulating the first torque (T A ) and/or the second torque (T B ) depending on the rotation speed (ω 2 ) of the secondary shaft ( 17 ) of the transmission ( 7 ).

2. The control method according to claim 1 , wherein the first torque (T A ) ranges from 3 to 7 Nm.

3. The control method according to claim 1 , wherein the first torque (T A ) ranges from 0.4% to 0.9% of a maximum torque of the internal combustion engine ( 4 ).

4. The control method according to claim 1 , wherein both clutches ( 16 A, 16 B) operate in slip mode, as, in each clutch, a driving disc ( 26 ) rotates at the same rotation speed (ω E ) as the internal combustion engine ( 4 ) and a driven disc ( 27 ) is still.

5. The control method according to claim 1 , wherein the rotation speed (ω 2 ) of the secondary shaft ( 17 ) of the transmission ( 7 ) is measured by a sensor ( 28 ) connected to the secondary shaft ( 17 ).

6. The control method according to claim 1 , wherein the first torque (T A ) and/or the second torque (T B ) are modulated so as to cause the rotation speed (ω 2 ) of the secondary shaft ( 17 ) of the transmission ( 7 ) to be zero.

7. The control method according to claim 6 , wherein the first torque (T A ) and/or the second torque (T B ) are modulated by means of a feedback control in which a control error (ε) is the difference between zero and the rotation speed (ω 2 ) of the secondary shaft ( 17 ) of the transmission ( 7 ).

8. The control method according to claim 7 , wherein the first torque (T A ) and/or the second torque (T B ) are modulated by a PID controller ( 30 ) which receives, as an input, the control error (ε).

9. The control method according to claim 1 , wherein, when the rotation speed (ω 2 ) of the secondary shaft ( 17 ) of the transmission ( 7 ) is not zero, the torque (T A , T B ) acting in the same direction as the rotation speed (ω 2 ) of the secondary shaft ( 17 ) of the transmission ( 7 ) is decreased.

10. The control method according to claim 1 , wherein, if the rotation speed (ω 2 ) of the secondary shaft ( 17 ) of the transmission ( 7 ) exceeds, in absolute value, a safety threshold, both clutches ( 16 A, 16 B) are opened.

11. The control method according to claim 1 , wherein, if a door of the road vehicle ( 1 ) is opened, both clutches ( 16 A, 16 B) are opened.

12. The control method according to claim 1 and comprising, cyclically and after a given amount of time has elapsed since the closing of the clutches ( 16 A, 16 B), the further steps of:
opening both clutches ( 16 A, 16 B);
quickly and repeatedly opening and closing, when both clutches ( 16 A, 16 B) are open, control valves ( 32 ) controlling the feeding of oil to the clutches ( 16 A, 16 B), so as to clean the control valves ( 32 ); and
closing the clutches ( 16 A, 16 B) again after having cleaned the control valves ( 32 ).

Assignees

• Ferrari Spa

Inventors

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

Classifications

• F16H59/40

  Output shaft speed · CPC title

• F16H57/12 Primary

  Arrangements for adjusting or for taking-up backlash not provided for elsewhere · CPC title

• F16H2061/0043

  Cleaning of hydraulic parts, e.g. removal of an orifice clogging · CPC title

• B60W10/10

  including control of change-speed gearings · CPC title

• F16H63/46

  Signals to a clutch outside the gearbox · CPC title