Browse Prior Art Database

Motor vehicle with an automatic manual transmission

IP.com Disclosure Number: IPCOM000236144D
Publication Date: 2014-Apr-09
Document File: 9 page(s) / 43K

Publishing Venue

The IP.com Prior Art Database

Abstract

A motor vehicle comprising: - an engine (2); 5 - a drive shaft (4); - an automatic manual transmission (5) for transmitting driving torque from the engine to the drive shaft, the transmission comprising gear shift members which are actuatable for engagement of different gears in the transmission; 10 - a clutch (6); and - an electronic control device (9) for controlling the gear shift members during a gear shift operation, the electronic control device being configured to effect the engagement of a selected starting gear only when the rotational speed error, i.e. the 15 difference in rotational speed between a gear wheel and an associated transmission shaft which are to be non-rotatably connected to each other by means of a gear shift member in order to engage the selected starting gear, is below a threshold value. 20 The electronic control device selects said threshold value among two or more predetermined threshold values of different magnitudes in dependence on one or more control conditions.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 29% of the total text.

Page 01 of 9

Motor vehicle with an automatic manual transmission

FIELD OF THE INVENTION AND PRIOR ART

The present invention relates to a motor vehicle with an

of the type where an electronic control device controls the execution of the gear shifts. In a first selectable operating mode, the electronic control device also decides when a gear shift is to be carried out and selects the gear to be engaged based on different operating parameters. In another selectable operating

The input shaft of the transmission will continue to rotate for some time when the motor vehicle has been stopped, the clutch has been disengaged and the transmission has been put into the neutral position. If a starting gear is engaged before the input

motor vehicle will be subjected to jerks and rockings. If said difference in rotational speed is large, the jerks and rockings might be so strong that the comfort of the driver is negatively affected. In order to reduce the discomfort for the driver, the electronic control device is normally configured to delay the

5

automatic manual transmission.

Heavy motor vehicles, such as for instance lorries or buses, are often provided with an automatic manual transmission, a so- called AMT. An automatic manual transmission is a transmission

10

15

mode, the driver of the motor vehicle decides when a gear shift is to be carried out and selects the gear to be engaged by means of a gear shift lever or the similar, whereupon the electronic control device controls the execution of the gear shift ordered by the driver. 20

25

shaft of the transmission has stopped rotating, there will, at the moment of the engagement of the starting gear, be a difference in rotational speed between the gear wheel and the associated transmission shaft which are non-rotatably connected to each other in order to engage the starting gear. In such a situation, the 30

35

engagement of the starting gear until said difference in rotational speed has been reduced to such an extent that it is below a fixed


Page 02 of 9

2

threshold value. If the threshold value is to low, the delay in the engagement of the starting gear could result in an annoyingly long delay when the driver wants to drive off after a short stop, for instance in front of traffic lights. Thus, the magnitude of the fixed threshold value is normally chosen as a compromise

between the conflicting requirements for good driving comfort and rapid engagement of the starting gear.

    SUMMARY OF THE INVENTION 10

The object of the present invention is to provide a solution to the above-mentioned problem.

Said object is achieved by a motor vehicle having the features defined in claim 1.

15

The motor vehicle of the present invention comprises:
- an engine;
- a drive shaft connected to two or more driving wheels of the motor vehicle;

20

- an automatic manual transmission for transmitting driving torque from the engine to the drive shaft, the transmission comprising gear shift members which are actuatable for engagement of...