Transmission control system

Patent metadata

Field	Value
Publication number	US-10451183-B2
Application number	US-201715825194-A
Country	US
Kind code	B2
Filing date	Nov 29, 2017
Priority date	Nov 30, 2016
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

A transmission which includes input and output shafts and first and second step-down devices for producing various step-down ratios. The first and second step-down devices are associated with first and second controllable clutches, respectively, in order to connect, in a torque-transmitting manner, the respective step-down device between the input shaft and the output shaft. A first gear of the transmission is obtained by actuating the first clutch and a second gear by actuating the second clutch. A method of controlling a gearshift, from the first gear to the second gear, includes the steps of determining operating condition parameters of the transmission; and determining optimized degrees of actuation of the clutches by a search process related to a transmission model that determines the degrees of actuation on the basis of operating condition parameters in relation to a predetermined optimization criterion. The transmission model is based on slip.

First claim

The invention claimed is:

1. A method of controlling a gearshift from a first to a second gear in a transmission, the transmission comprising: an input shaft and an output shaft; first and second step-down devices for providing various step-down ratios; and, in order to connect the respective first and second step-down devices in a torque-transmitting manner between the input shaft and the output shaft, a first clutch being associated with the first step-down device and a second clutch being associated with the second step-down device; and the first gear being obtainable by actuating the first clutch and the second gear by activating the second clutch, the method comprises:
determining operating condition parameters of the transmission, the operating condition parameters comprising at least one of a rotational speed and a transmitted toque of at least one of the input shaft, the output shaft, the first clutch, the second clutch, an intermediate shaft, and input sides and output sides of the first and the second step-down devices;
determining optimized degrees of actuation of the first and the second clutches by a search method relating to a transmission model, which determines the degrees of actuation on a basis of the operating condition parameters in relation to predetermined optimization criterion, and the degree of actuation being defined as a percentage of clutch engagement on a scale from a fully disengaged condition to a fully engaged condition;
basing the transmission model on slip; and
adjusting the first and the second clutches to the determined degrees of actuation.

2. The method according to claim 1 , further comprising determining a plurality of the degrees of actuation of the first and the second clutches for a sequence of future fixed time-points, and adjusting the first and the second clutches, at the fixed time points, to the degrees of actuation corresponding the fixed time points.

3. The method according to claim 2 , further comprising predetermining an end time at which the gearshift is completed, and repeatedly redetermining the optimized degrees of actuation of the first and the second clutches to provide optimized pluralities of degrees of actuation for a time that remains until the end time.

4. The method according to claim 2 , further comprising determining actuation trajectories for the first and the second clutches on a basis of the degrees of actuation, and the actuation trajectories being defined as the degree of actuation of the first and the second clutches over a predetermined time interval.

5. The method according to claim 1 , further comprising controlling the gearshift from the first gear to the second gear in the transmission with a control system for the first and the second clutches; and
determining the degrees of actuation, predictively taking into account a desired load torque.

6. The method according to claim 1 , further comprising forming the transmission with two transmission groups which are connected in series with one another.

7. A control device for controlling a gearshift from a first gear to a second gear in a transmission which has an input shaft and an output shaft; first and second step-down devices for providing various step-down ratios; a first clutch being associated with the first step-down device and a second clutch being associated with the second step-down device in order to connect the respective step-down devices in a torque-transmitting manner between the input shaft and the output shaft; and the first gear being obtainable by actuating the first clutch and the second gear by activating the second clutch, the control device comprising:
an interface for detecting operating condition parameters of the transmission, the operating condition parameters comprising at least one of a rotational speed and a transmitted toque of at least one of the input shaft, the output shaft, the first clutch, the second clutch, an intermediate shaft, and input sides and output sides of the first and the second step-down devices;
a processing device for determining optimized degrees of actuation of the first and the second clutches by a search method related to a transmission model, which determines the degrees of actuation of the first and the second clutches on a basis of the operating condition parameters in relation to a predetermined optimization criterion, and the degree of actuation being defined as a percentage of clutch engagement on a scale from a fully disengaged condition to a fully engaged condition;
the transmission model is based on slip; and
a control device for adjusting the first and the second clutches to the determined degrees of actuation.

8. A method of controlling a gearshift from a first gear to a second gear in a transmission having an input shaft, an output shaft, and first and second step-down devices for providing various step-down ratios, the first step-down device having a first clutch for connecting the first step-down device in a torque-transmitting manner between the input shaft and the output shaft, and the second step-down device having a second clutch for connecting the second step-down device in a torque-transmitting manner between the input shaft and the output shaft, the first gear being obtained by actuating the first clutch and the second gear being obtained by activating the second clutch, the method comprising:
determining operating condition parameters of the transmission the operating condition parameters comprising at least one of a rotational speed and a transmitted toque of at least one of the input shaft, the output shaft, the first clutch, the second clutch, an intermediate shaft, and input sides and output sides of the first and the second step-down devices;
determining optimized degrees of actuation of the first and the second clutches by a search method relating to a transmission model, which determines the degrees of actuation on a basis of the operating condition parameters in relation to a predetermined optimization criterion, and the degrees of actuation being defined as percentages of clutch engagement on a scale from a fully disengaged condition to a fully engaged condition;
basing the transmission model on clutch slip; and
adjusting engagement of the first clutch to a determined degree of actuation of the first clutch and adjusting engagement of the second clutch to a determined degree of actuation opt the second clutch.

9. The method according to claim 4 , further comprising continually determining the actuation trajectories for the first and the second clutches while the gearshift is in progress.

Assignees

• Zahnradfabrik Friedrichshafen
• Zf Friendrichshafen Ag

Inventors

• Szabo Tomas
• Graichen Knut
• Hentzelt Sebastian

Classifications

• F16H2306/30

  characterised by the way or trajectory to a new ratio, e.g. by performing shift according to a particular algorithm or function · CPC title

• F16H2061/161

  by checking feasibility of shifts, i.e. determine if requested shift can be successfully completed and post shift values are in an acceptable range · CPC title

• F16H2061/085

  Timing of auxiliary gear shifts · CPC title

• F16H2300/02

  Computing a new ratio · CPC title

• F16H61/70

  specially adapted for change-speed gearing in group arrangement, i.e. with separate change-speed gear trains arranged in series, e.g. range or overdrive-type gearing arrangements · CPC title