METHOD FOR DETERMINING THE ENGAGED GEAR IN A MANUAL GEARBOX

Abstract

A method for determining the engaged gear in a manual gearbox of a vehicle comprising a number of gears is described, wherein the vehicle comprises an engine, the manual gearbox, and at least one clutch. The method comprises the following steps: determination of the revolution rate of the engine as a function of time; differentiating the determined revolution rate of the engine against time; determination of the speed of the vehicle; and determination of the engaged gear based on characteristic curves of the revolution rate of the engine as a function of time for a number of the gears in the case of a fixed rate of engagement of the clutch, the revolution rate of the engine, the differential of the revolution rate of the engine against time and the speed of the vehicle.

Claims

1. A method for operating a vehicle comprising an engine, a gearbox with a number of gears, and at least one clutch, the method comprising: disengaging the at least one clutch; determining a rate of decrease in a speed of the vehicle as a function of time; determining a revolution rate of an engine of the vehicle as a function of time; differentiating the determined revolution rate of the engine against time; determining a speed of the vehicle, determining an engaged gear based on characteristic curves of the revolution rate of the engine as a function of time for a number of the gears of the gearbox, the characteristic curves based on the revolution rate of the engine, the differential of the revolution rate of the engine against time, and the speed of the vehicle; engaging a clutch of the at least one clutch up to a specified position; and outputting the determined gear to be engaged.

2. The method of claim 1 wherein the at least one clutch comprises an electronically controlled clutch.

3. The method of claim 1 wherein the gearbox is an automated manual gearbox.

4. The method of claim 1 wherein the at least one clutch comprises two clutches and the gearbox and two clutches form a dual clutch transmission.

5. The method of claim 1 further comprising adaptively modifying the specified position.

6. The method of claim 1 wherein the determination of the revolution rate of the engine as a function of time is carried out within a calibratable time window.

7. A method for determining an engaged gear in a vehicle, the method comprising: determining an engine speed of the vehicle as a function of time; differentiating the determined engine speed against time; determining a vehicle speed; and comparing the determined engine speed and differentiated engine speed to characteristic curves of engine speed as a function of time for a number of gears of a gearbox of the vehicle at the determined vehicle speed.

8. The method of claim 7 wherein the characteristic curves of engine speed are determined as a function of time based on a fixed rate of engagement of a clutch of the vehicle.

9. The method of claim 8 wherein the clutch is at least partly disengaged while the method is being carried out.

10. The method of claim 7 wherein the characteristic curves are calibrated using a mass of the vehicle and/or an inertia of an engine of the vehicle.

11. The method of claim 7 wherein the determination of the engine speed as a function of time and/or the determination of the speed of the vehicle is/are carried out within a specified time window.

12. The method of claim 11 wherein the time window is equal to or shorter than 300 milli-seconds.

13. A vehicle comprising: an engine; a gearbox with a number of gears; at least one clutch; and a controller programmed to determine a revolution rate of an engine of the vehicle as a function of time, differentiate the determined revolution rate of the engine against time, determine a speed of the vehicle, and determine an engaged gear based on characteristic curves of the revolution rate of the engine as a function of time for the gears of the gearbox, the characteristic curves based on the revolution rate of the engine, the differential of the revolution rate of the engine against time, and the speed of the vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 shows schematically a method according to the invention for determining the engaged gear in the form of a flow chart.

[0028] FIG. 2 shows schematically the dependency of the revolution rate of the engine on time for two gears.

[0029] FIG. 3 shows schematically a method according to the invention for operating a vehicle in the form of a flow chart.

[0030] FIG. 4 shows schematically a motor vehicle according to the invention.

DETAILED DESCRIPTION

[0031] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0032] A method according to the invention for determining the engaged gear in a manual gearbox using the flow chart shown in FIG. 1 is described in detail below. In step 1, the revolution rate of the engine is determined, for example measured, as a function of time. In step 2, the revolution rate determined in step 1 is differentiated against time. In step 3, the speed of the vehicle is determined, for example measured. In step 4, the engaged gear is determined, for example calculated, based on gear-specific characteristic curves of the revolution rate of the engine, the revolution rate of the engine, the differential of the revolution rate of the engine against time and the speed of the vehicle.

[0033] Said steps can be carried out respectively or as a whole within a specified time window, for example within 300 milliseconds or less. While the method for determination of the engaged gear is being carried out, the drive train can be at least partly open. The clutch can also be at least partly disengaged.

[0034] The characteristic curves of the revolution rate of the engine as a function of time for a number of the gears are determined for the case of a fixed rate of engagement of the clutch, i.e. for a specified rate of engagement of the clutch or of bringing the clutch plates together. The characteristic curves can be determined during the process. The characteristic curves can also be determined for the respective vehicle once, preferably before the application of the method, and can be available as data records for use during the method according to the invention. The characteristic curves can be calibrated while taking into account/using the mass of the vehicle and/or the inertia of the engine and/or the position of the clutch as a function of time.

[0035] FIG. 2 shows schematically the dependency of the revolution rate of the engine, n, in revolutions per minute (1/min) on the time, t, in seconds (s) for two gears. In the example shown, the curves 21 represent the engagement of the 3rd gear and the curves 22 represent the engagement of the 5th gear. The detection window is characterized by the reference number 23.

[0036] A method according to the invention for operating a vehicle using the flow chart shown in FIG. 3 is described in detail below. The initial situation at step 31 is of a rolling vehicle with a disengaged clutch. In step 32, the decrease in the speed of the vehicle is determined, in particular measured, as a function of time. This can be carried out within a specified time window. In step 33, the engaged gear can be determined by means of a method described in connection with FIG. 1. In step 34, the clutch is engaged or closed up to a specified position. This can be an adaptively learned position.

[0037] In step 35, the revolution rate of the engine is determined as a function of time and the differential of the revolution rate against time is determined, for example is calculated, and is analysed. This can be carried out within a specified time window. During the analysis, the gear to be engaged is determined based on the differential of the revolution rate of the engine against time and the characteristic curves. In step 36, a recommendation for the gear that is to be engaged is output, for example to a user interface.

[0038] In FIG. 4, a motor vehicle 40 according to the invention is shown schematically. The motor vehicle 40 can be a passenger motor vehicle, a truck, a motor cycle or a moped. The motor vehicle 40 comprises an engine 44 and a manual gearbox 41, for example an automated manual gearbox. The manual gearbox 41 can be designed as a single clutch transmission or a dual clutch transmission. The motor vehicle also comprises a clutch 42, for example an electronically controlled clutch. The clutch 42 is functionally connected to the manual gearbox 41 and the engine 44 in the usual manner. Moreover, the motor vehicle 40 comprises a controller 43 that is designed for carrying out the method that is described above. The controller 43 is designed for transmitting suitable signals to the clutch 42 and/or the manual gearbox 41 for this.

[0039] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.