Control of a change-gear transmission

Abstract

A change-gear transmission system includes a transmission that can be switched between multiple gears, a gearshift lever for selecting between the gears of the transmission, an automatically actuatable clutch, which is arranged in a drive train in series with the transmission and a control unit for automatically opening the clutch while maintaining a gear engaged in the transmission when a condition for the transition into coasting or gliding mode is fulfilled. The control unit is configured to detect a touch of the gearshift lever by the driver, to open the clutch only when no touch of the gearshift lever is detected, and further in the case that in the coasting or gliding mode, a touch of the gearshift lever is detected, to close the clutch while maintaining the engaged gear.

Claims

1. A change-gear transmission system for a vehicle comprising: a transmission switchable between a plurality of gears; a gearshift lever for selectively engaging one of the plurality of gears; a clutch assembly arranged in a drive train in series with the transmission and operable to configure the drive train in a coasting mode; an actuator coupled to the clutch assembly and operable to open and close the clutch assemble; and a control unit configured to detect a touch of the gearshift lever and to determine a condition for transiting the drive train into the coasting mode, wherein the control unit operates the actuator to open the clutch assembly when the condition for transiting into the coasting mode is fulfilled and the gearshift lever is not touched.

2. The change-gear transmission system according to claim 1, wherein the drive train is in the coasting mode and the control unit is further configured to close the clutch assembly while maintaining an engaged gear when a touch of the gearshift lever is detected.

3. The change-gear transmission system according to claim 2, wherein the condition comprises an actuation condition of an accelerator pedal indicating that the accelerator pedal is unactuated or only slightly actuated so that the direction of torque transmission in the drive train is inverted.

4. The change-gear transmission system according to claim 2, wherein the gearshift lever is movable between a plurality of shifting positions, wherein each gear of the transmission is assigned exactly one shifting position.

5. The change-gear transmission system according to claim 2, wherein the control unit is configured to check if a currently engaged gear is appropriate for a vehicle speed prior to a closing of the clutch, and closing the clutch only when the currently engaged gear is appropriate for the vehicle speed.

6. The change-gear transmission system according to claim 5, wherein the control unit is configured to determine an appropriate gear for the vehicle speed and to indicate the appropriate gear.

7. The change-gear transmission system according to claim 2, further comprising a proximity sensor on the gearshift lever in data communication with the control unit for detecting the touch of the gearshift lever by the driver.

8. The change-gear transmission system according to claim 2, further comprising a position sensor for the gearshift lever in data communication with the control unit to detect a change of the position of the gearshift lever indicating the touch of the gearshift lever by the driver.

9. A method for controlling a change-gear transmission system having a transmission switchable between a plurality of gears, a gearshift lever for selectively engaging one of the plurality of gears, a clutch assembly arranged in a drive train in series with the transmission and operable to configure the drive train in a coasting mode, an actuator coupled to the clutch assembly and operable to open and close the clutch assemble, and a control unit configured to selectively control the actuator, the method comprising: determining when a first condition for opening the clutch assembly is fulfilled; determining a second condition when the gearshift lever is untouched; and opening the clutch when the first and second conditions are fulfilled.

10. The method for controlling according to claim 9, wherein the drive train is in the coasting mode and the method further comprises closing the clutch assembly while maintaining an engaged gear when a touch of the gearshift lever is detected.

11. The method according to claim 10, further comprising: determining when the engaged gear is appropriate for a vehicle speed; and closing the clutch assembly when the engaged gear is appropriate for the vehicle speed.

12. The method according to claim 11, further comprising: determining an appropriate gear for the vehicle speed; and indicating the appropriate gear when the engaged gear is different than the appropriate gear.

13. A non-transitory computer readable medium comprising program instructions, which when executed on a computer enable the computer to: determine when a first condition for opening the clutch assembly is fulfilled; determine a second condition when the gearshift lever is untouched; open the clutch when the first and second conditions are fulfilled; close the clutch assembly while maintaining an engaged gear when a touch of the gearshift lever is detected, and the drive train is in the coasting mode.

14. The non-transitory computer readable medium according to claim 13, further comprising the program instructions, which when executed on the computer enable the computer to: determine when the engaged gear is appropriate for a vehicle speed; and close the clutch assembly when the engaged gear is appropriate for the vehicle speed.

15. The non-transitory computer readable medium according to claim 13, further comprising the program instructions, which when executed on the computer enable the computer to: determine an appropriate gear for the vehicle speed; and indicate the appropriate gear when the engaged gear is different than the appropriate gear.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements.

(2) FIG. 1 shows a block diagram of a vehicle according to the present disclosure; and

(3) FIG. 2 shows a flow diagram of a working method carried out by a control unit of the vehicle.

DETAILED DESCRIPTION

(4) The following detailed description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background of the invention or the following detailed description.

(5) FIG. 1 shows in a schematic top view a motor vehicle with an engine 1 and a drive train which connects the engine 1 with wheels 2 of a running gear and in which a transmission 3 and a clutch 4 based on the flow direction of the torque from the engine 1 to the running gear are arranged in series.

(6) The transmission 3 is controlled with the aid of a gearshift lever 5 in a conventional manner, which can be moved in a shifting gate 6 between the positions assigned to the different gears of the transmission 3, which in each case are located at the ends of shifting slots of the shifting gate 6. The gearshift lever 5 can be coupled to an internal shifting of the transmission 3 mechanically, for example via cable pulls, so that each gear of the transmission corresponds exactly to one position of the gearshift lever 5.

(7) On the shifting gate 6, a position sensor 7 for detecting the position of the gearshift lever 5, typically in the form of two angle sensors for detecting angles of the gearshift lever in the shifting degree of freedom or in the selecting degree of freedom, is provided. Complementarily, a proximity sensor 18 can be provided in a grip of the gearshift lever 5, which reacts to the handle being touched by the driver's hand.

(8) The clutch 4, on the one hand, is controllable by the driver via a clutch pedal 8 and, on the other hand, by an electronic control unit 10 via an actuator 9.

(9) The electronic control unit 10 is connected to a load sensor 11 which supplies a signal that is representative for the actual engine load or the engine load demanded by the driver. As shown in the figure, the load sensor 11 can be arranged on an accelerator pedal 12 in order to detect the extent of the actuation of the accelerator pedal 12 by the driver.

(10) Furthermore, a rotational speed sensor 13 on an output shaft of the engine 1, a speedometer 14, a sensor 15 for detecting the actuation of the clutch pedal 8 and a display 16 arranged on the instrument panel of the vehicle are connected to the control unit 10.

(11) FIG. 2 shows a working method of the control unit 10 in the form of a flow diagram. At S1, the control unit 10 continuously monitors the position of the accelerator pedal 12, of the clutch pedal 8 and of the gearshift lever 5 by way of the outputs of the sensors 11, 15 and 7. When it is then determined at S2 that the driver releases the accelerator pedal 12 without actuating the clutch pedal 8, the control unit 10 again queries the position sensor 7 at S3 and checks at S4 if the position of the gearshift lever 5 detected by position sensor 7 has change since S1. If yes, this indicates that the driver could have touched the gearshift lever 5 with the intention of shifting the transmission 3. In this case, nothing further happens and control returns to the monitoring of the sensors 11, 15, 7 at S1. If, by contrast, it is determined that the position of the gearshift lever 5 is unchanged, it is concluded that the gearshift lever 5 is not touched, the control unit 10 then opens the clutch 4 with the aid of the actuator 9 at S5.

(12) If a proximity sensor 18 is present on the gearshift lever 5, the control unit 10 can also make the decision at S4 as to whether the gearshift lever 5 is touched or not with the aid of the proximity sensor 18. In this case, the monitoring of at S1 can be limited to accelerator pedal 12 and clutch pedal 16.

(13) By opening the clutch 4, the vehicle enters a coasting mode or, if the engine 1 is additionally also switched off at S5 into the gliding mode. During the coasting or gliding mode, the control unit 10 monitors the speedometer 14 at S6 and determines a gear by way of the measured speed of the vehicle which should be engaged in the transmission 3 in the case that the clutch 4 has to be closed again at S7. If it is desired, the gear so determined can be displayed on the instrument panel 16. The determined gear can also be compared beforehand with the currently engaged gear, which the control unit 10 determines from the data of the position sensor 7, and the determined gear may be displayed only when it is distinct from the currently engaged gear. In other words, the manner in which the determined gear is displayed can be made dependent on whether it corresponds to the currently engaged gear or not. Regardless of which alternative is selected, the driver in each case can recognize by way of the instrument panel 16 if determined and engaged gear correspond.

(14) The control unit 10, furthermore, queries the load sensor 11 and a brake pressure sensor 19 at S8 and the position sensor 7 or if applicable the proximity sensor 18 at S10. When the load sensor 11 indicates that the accelerator pedal 12 is again actuated or the brake pressure sensor 19 indicates an actuation of the brake pedal 17 at S9 or when the position sensor 7 or proximity sensor 18 indicates that the driver touches the gearshift lever 5 at S11, a check is made at S12 if the determined and engaged gear correspond. If this is the case, the control unit 10 closes the clutch 4 and, provided the same has been switched off previously, switches the engine on again at S13. Control then reverts to S1. If none of these conditions is fulfilled, the control then reverts to S6.

(15) In the case of the non-correspondence at the latest, the control unit 10 addresses the display instrument 16 at S14 in order to point out to the driver that with the currently engaged gear the clutch 4 cannot be closed. The notification may include a display on the instrument panel 16 of the determined gear number. Alternately the notification may replace the engaged gear number with the determined gear number in a modified display format, for example flashing instead of continuous or in a different color. Additional notifications may include a display of the difference or direction of the determined gear number relative to the engaged gear number, for example in the form of plus or minus signs or directional arrows, such that the number of signs indicates the number of the gear stages to be upshifted or downshifted.

(16) Whether the driver reacts to this display by shifting or by actuating the brake pedal is left to him. Meanwhile, the control circuit 10 continues monitoring at S6. As soon as this reveals upon a repetition at S12 that engaged and determined gear coincide, the processing branches to S13 in order to again leave the coasting or gliding mode.

(17) While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment as contemplated herein. It should be understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.