GB2510026A

GB2510026A - Method of providing a warning to indicate unintentional driver clutch actuation

Info

Publication number: GB2510026A
Application number: GB1319632.4A
Authority: GB
Inventors: Sureshkumar Gurusamy; D Jayachandran; Karthikeyan Tr
Original assignee: Daimler AG
Current assignee: Mercedes Benz Group AG
Priority date: 2013-11-07
Filing date: 2013-11-07
Publication date: 2014-07-23
Also published as: GB201319632D0

Abstract

A vehicle having a clutch pedal (14, fig 1) via which the clutch is adjustable by the driver 16 between at least one engaged state and at least one disengaged state, the method comprising: providing a signal characterizing the position of the accelerator pedal (10, fig 1); providing a second signal characterizing the state of the clutch; providing a third signal characterizing a slippage between the input and output shafts of the clutch; outputting at least one warning signal 30, in dependency of the first signal, the second signal and the third signal to indicate an unintentional clutch actuation caused by the driver. The warning may be issued if the slippage is below 10%, preferably 6% for a predetermined period of time, preferably at least 30 seconds and if the accelerator pedal is in a position different from the idle position effecting idling of the engine.

Description

Method for Operating a Vehicle The invention relates to a Method for operating a vehicle.

Vehicles comprising a manual gear box, an engine and a clutch are well known from the general prior art. The clutch is adjustable between at least one engaged state and at least one disengaged state. In the engaged state of the clutch a first shaft of the engine is coupled to a second shaft of the vehicle, so that, for example, the first shaft can drive the second shaft via the engaged clutch. In the disengaged state of the clutch the first shaft is decoupled from the second shaft.

Usually, the second shaft is configured as or coupled to an input shaft of the manual gear box so that torques provided by the engine via the first shaft can be transmitted from the first shaft via the engaged clutch to the second shaft and the gear box.

In order to change gears of the gear box manually, the disengaged state of the clutch is to be adjusted. For this purpose the vehicle has a clutch pedal via which the clutch is adjustable by the driver between the engaged state and the disengaged state. In order to move the clutch from the engaged state into the disengaged state the driver depresses the clutch pedal. Having changed the gear the driver can release the clutch pedal so that the clutch pedal is moved back into a non-depressed state by means of, for example, a spring. Thus, the clutch is moved from the disengaged state into the engaged state.

US 4651 142 shows an apparatus to determine friction values on a clutch and to detect an overload operating condition on such clutch disposed in an operating mechanism intermediate a motor and a drive train means.

It has been shown that situations can occur in which drivers of vehicles with manual gear boxes actuate the clutches unintentionally but slightly. This is also referred to as clutch riding". This clutch riding during driving can result in high fuel consumption and clutch wear.

It is therefore an object of the present invention to provide a method by means of which excessive and unnecessary fuel consumption and clutch wear can be avoided.

This object is solved by a method having the features of patent claim 1. Advantageous embodiments with expedient and non-trivial developments of the invention are indicated in the other patent claims.

The method according to the present invention serves for operating a vehicle comprising at least one engine in the form of, for example, an internal combustion engine. The vehicle also comprises at least one moveable operating element via which a power output of the engine is adjustable by the driver of the vehicle. For example, the operating element is an accelerator pedal which is also referred to as "accelerator" or gas pedal".

Furthermore, the vehicle comprises at least one clutch for coupling a first shaft of the engine to a second shaft of the vehicle. For example, the first shaft can be a crank shaft of the internal combustion engine. The second shaft can be an input shaft of a manual gear box of the vehicle.

The vehicle also comprises at least one clutch pedal. Via the clutch pedal the clutch is adjustable by the driver between one at least one engaged state and at least one disengaged state. In the engaged state the first shaft is coupled to the second shaft by means of the clutch so that, for example, the second shaft can be driven by the first shaft or vice versa. In the disengaged state of the clutch the first shaft is decoupled from the second shaft so that torques provided by the engine via its first shaft cannot be transmitted to the second shaft via the clutch.

The method according to the present invention comprises a first step in which a first signal characterizing the position of the operating element is provided. For example, the position of the operating element is detected by at least one first detecting element providing the first signal which characterizes the detected position. Thereby, it can be detected whether the operating element is actuated by the driver or not.

The method according to the present invention comprises a second step in which a second signal characterizing the state of the clutch is provided. For example, the state of the clutch is detected by at least one second detecting element. The second detecting element can detect, for example, the position of the clutch pedal which in turn can characterize the state of the clutch. Moreover, it is possible to detect the state of the clutch by detecting the position of at least one component of the clutch, the component being moveable between the engaged state and the disengaged state. The position of the clutch pedal can be detected as well so that the position of the component of the clutch can be compared with the position of the clutch pedal.

The method according to the present invention comprises a third step in which a third signal characterizing a slippage between the shafts is provided. When slippage between the shafts occurs, the shafts rotate at different speeds.

The method according to the present invention further comprises a fourth step in which at least one warning signal is output in the interior of the vehicle in dependency of the first signal, the second signal and the third signal to indicate an unintentional clutch actuation caused by the driver. By means of the warning signal the unintentional clutch actuation can be pointed out to the driver so that the driver can stop actuating the clutch via the clutch pedal unintentionally. Thereby, excessive and unnecessary fuel consumption and clutch wear due to unintentional actuation of the clutch can be avoided.

For example, the warning signal is a sound signal and/or a light signal and/or a vibration at least one component of the vehicle. In other words, the warning signal can be a signal which can be noticed by the driver haptically and/or optically and/or acoustically.

In an advantageous embodiment of the invention the warning signal is output if the slippage is below a threshold value of 10%, preferably 6%.

In a further advantageous embodiment of the invention the warning signal is output if the position of the operating element is different from an idle position effecting idling of the engine.

In a further advantageous embodiment of the invention the warning signal is output if the slippage is above or below a predeterminable threshold value during a predeterminable period of time.

In a further advantageous embodiment of the invention the predeterminable period of time is at least thirty seconds.

Further advantages, features, and details of the invention derive from the following description of a preferred embodiment as well as from the drawings. The features and feature combinations previously mentioned in the description as well as the features and feature combinations mentioned in the following description of the figures and/or shown in the figures alone can be employed not only in the respective indicated combination but also in any other combination or taken alone without leaving the scope of the invention.

The drawings show in: Fig. 1 a schematic front view of three operating elements in the form of pedals of the vehicle, wherein the vehicle is operated in such a way that at least one warning signal is output in the interior of the vehicle to indicate an unintentional clutch actuation caused by the driver; Fig. 2 a schematic perspective view of the driver's left foot activating the clutch of the vehicle unintentionally; Fig. 3 a flow diagram for illustrating a method for operating the vehicle in which method the warning signal is output in the interior of the vehicle if an unintentional clutch activation caused by the driver is detected.

Fig. 1 shows three operating elements of a vehicle. For example, the vehicle is a passenger vehicle. However, the features and feature combinations mentioned above and below can also apply to other vehicles such as but not limited to commercial vehicles, buses, trucks etc.. A first one of said operating elements is an accelerator pedal 10 which is also referred to as accelerator' or gas pedal'. A second one of said operating elements is a brake pedal 12. The third operating element is a clutch pedal 14. The driver of the vehicle can operate the operating elements by his feet.

The vehicle also comprises at least one engine in the form of an internal combustion engine. The driver can adjust the power output of the internal combustion engine via the accelerator pedal 10. By depressing the accelerator pedal 10 the power output is increased. If the accelerator pedal 10 is not depressed it is moved into an idle position shown in Fig. 1 by, for example, at least one spring. If the internal combustion engine is activated and the accelerator pedal 10 is in its idle position the internal combustion engine is running idle.

The power of the internal combustion engine is output via a first shaft in the form of a crank shaft of the internal combustion engine. In other words, torques of the internal combustion engine are output via the crank shaft. The vehicle further comprises a driving brake system for decelerating the vehicle. The driving brake system is activated by the driver via the brake pedal 12. In order to activate the driving brake system and, thus, decelerate the vehicle the brake pedal 12 needs to be depressed.

Furthermore, the vehicle comprises at least one clutch for coupling the crank shaft of the internal combustion engine to a second shaft of the vehicle. For example, the second shaft is an input shaft of a manual gear box of the vehicle. The driver can adjust the clutch between at least one engaged state and at least one disengaged state via the clutch pedal 14. In the engaged state the crank shaft is coupled to the second shaft by means of the clutch. In the disengaged state the crank shaft is decoupled from the second shalt so that torques cannot be transmitted from the crank shalt to the second shaft or vice versa.

In order to move the clutch from its engaged state into its disengaged state the clutch pedal 14 needs to be depressed. This means the clutch is in its engaged state when the clutch pedal 14 is not depressed. The clutch pedal 14 is moved into and held in its non-depressed position shown in Fig. 1 by, for example, at least one spring. Said spring also moves the clutch from its disengaged state into the engaged state when the driver releases the clutch pedal 14.

Fig. 2 shows the driver's left foot 16 resting on the clutch pedal 14. Thereby, a force illustrated by a directional arrow 18 is exerted from the left foot 16 on the clutch pedal 14.

Thereby, the clutch pedal 14 is depressed and, thus, moved a little bit out of its non-depressed position. Thus, the clutch is actuated by the driver although the driver actually does not want to actuate the clutch since, for example, the vehicle is driving at a constant speed.

However, the slight clutch actuation caused by the left foot 16 resting on the clutch pedal 14 causes a slight slippage between the crank shaft and the second shaft. This can result in a high fuel consumption and clutch wear being unnecessary since there is no need to actuate the clutch.

Fig. 3 shows a flow diagram for illustrating a method for operating the vehicle, wherein excessive fuel consumption and clutch wear caused by unintentional clutch actuations can be avoided. In said method the position of the accelerator pedal 10 is detected by a first sensor 20. The sensor 20 is connected to a control unit 22 of the vehicle by, for example, a CAN bus. The first sensor 20 provides a first signal characterizing the position of the accelerator pedal 10, wherein the first signal is transmitted from the first sensor 20 to the control unit 22 and received by the control unit 22. Furthermore, the state of the clutch is detected by a second sensor 24 being coupled to the control unit 22 via the CAN bus. The second sensor 24 provides a second signal characterizing the state of the clutch. For example, the position of the clutch pedal 14 is detected by the second sensor 24, the position of the clutch pedal 14 corresponding to the state of the clutch.

Thus, the second signal can also characterize the position of the clutch pedal 14. The second signal provided by the second sensor 24 is transmitted from second sensor 24 to the control unit 22 and received by the contiol unit 22.

The control unit 22 is also connected to an engine control unit 26 via the CAN bus. The engine control unit 26 provides a third signal characterizing a slippage between the crank shaft and the second shaft. If slippage occurs between the crank shaft and the second shaft the crank shaft and the second shaft rotate at different speeds. This can be detected by the engine control unit 26. The engine control unit 26 provides the third signal which is transmitted from the engine control unit 26 to the control unit 22 and received by the control unit 22.

In a control logic 28 the control unit 22 checks on the basis of the first signal if the accelerator pedal 10 is depressed, i.e. moved out of its idle position. Moreover, the control unit 22 checks on the basis of the second signal if the clutch pedal 14 is depressed.

Moreover, the control unit 22 checks in the control logic 28 on the basis of the third signal if the slippage is below a threshold value of 6%. The slippage can occur between a flywheel of the internal combustion engine and the input shaft of the manual gear box.

Moreover, a fourth signal characterizing the vehicle speed and/or a fifth signal characterizing the torque demanded by the driver can be monitored. If the accelerator pedal 10 and the clutch pedal 14 are depressed and if the slippage is below the threshold value of 6% a time counter is started. By means of the time counter a period of time during which the accelerator pedal 10 is depressed incessantly, the clutch pedal 14 is depressed incessantly and the slippage is below the threshold value of 6% incessantly is measured. If the measured period of time is above a threshold value of, for example, thirty seconds at least one warning signal 30 is output in the interior of the vehicle to indicate an unintentional clutch actuation caused by the driver.

This means at least one warning signal in the interior of the vehicle is output in dependency of the first signal, the second signal and the third signal, the warning signal indicating an unintentional clutch actuation caused by the driver. Thereby, the driver's attention can be drawn to the fact that he is actuating the clutch unintentionally which is also referred to as riding the clutch'. As a consequence, the driver can stop unintentionally depressing the clutch pedal 14 thereby avoiding unnecessary fuel consumption and unnecessary clutch wear.

With respect to the detected slippage a threshold value of 10%, in particular 6% is advantageous since a slippage being above said threshold value usually indicates an intentional clutch actuation during, for example, driving heavy traffic oi going iound a band.

The warning signal 30 output in the interior can be an optical and/or acoustical and/or haptical signal so that the driver can notice the warning signal 30 optically and/or acoustically and/or haptically.

List of reference signs accelerator pedal 12 break pedal 14 clutch pedal 16 left foot 18 directional arrow first sensor 22 control unit 24 second sensor 26 engine contol unit 26 contrologic warning signal

Claims

Claims A method for operating a vehicle comprising at least one engine, at least one movable operating element (10) via which a power output of the engine is adjustable by the driver of the vehicle, at least one clutch for coupling a first shaft of the engine to a second shaft of the vehicle, and at least one clutch pedal (14) via which the clutch is adjustable by the driver between at least one engaged state and at least one disengaged state, the method comprising: -providing a first signal characterizing the position of the operating element (10), -providing a second signal characterizing the state of the clutch, -providing a third signal characterizing a slippage between the shafts, -outputting at least one warning signal (30) in the interior of the vehicle in dependency of the first signal, the second signal and the third signal to indicate an unintentional clutch actuation caused by the driver.
2. The method according to claim 1, characterized in that the warning signal is output if the slippage is below a threshold value of 10%, preferably 6%.
3. The method according to any one of claims 1 or 2, characterized in that the warning signal is output if the position of the operating element (10) is different from an idle position effecting idling of the engine.
4. The method according to any one of the preceding claims, characterized in that the warning signal (30) is output if the slippage is above or below a predeterminable threshold value during a predeterniinable period of time.
5. The method according to claim 4, characterized in that the predeterminable period of time is at least thirty seconds.