WO2011053229A1

WO2011053229A1 - Gear lever with adaptive damping

Info

Publication number: WO2011053229A1
Application number: PCT/SE2010/051145
Authority: WO
Inventors: Lasse Ronvall
Original assignee: Scania Cv Ab
Priority date: 2009-10-29
Filing date: 2010-10-21
Publication date: 2011-05-05
Also published as: SE1050919A1; EP2494239A4; EP2494239A1; BR112012009762A2; SE534224C2

Abstract

The invention relates to a method and a system for adjusting the mechanical damping or counterforce in a gear lever (1)in a vehicle to the current driving situation, the driver's driving style and / or the way he / she changes gear. The invention is achieved by detecting the current driving situation, the driver's driving style and / or the way he / she changes gear, by calculating on the basis of the current driving situation, the driver's driving style and / or the way he / she changes gear an instantaneous value for a mechanical damping / counterforce(F) desired in the gear lever (1), and by using the calculated instantaneous value as a basis for causing an actuator (11, 20) to exert the desired damping / counterforce(F) in the gear lever (1)and thereby adjusting the damping / counterforce (F) of the gear lever (1) in relation to the current driving situation, the driver's driving style and / or the way he / she changes gear.

Description

GEAR LEVER WITH ADAPTIVE DAMPING

TECHNICAL FIELD

The present invention relates generally to a method and a system for changing gear in a vehicle, particularly for heavy commercial vehicles such as trucks etc. The invention relates in particular to a method and a gear change mechanism which make the gear change process better and more comfortable and which adjust the mechanical movement resistance in the gear lever to the current driving situation, the driver' s driving style and/or the way he/she changes gear so that the gear lever movement is braked/damped if for example the driver operates the gear lever too forcefully or changes gear too quickly .

STATE OF THE ART

It is becoming increasingly common that gear change systems in vehicles do not impart an expected mechanical resistance in the gear lever such as was usual in previous conventional mechanical gear change systems. This applies not least to gear change systems based on so-called electronic gear levers for electrically operated gear changing. Achieving a

good/comfortable and expected sensation for the driver in such a gear lever entails some form of mechanical damping in the gear lever, i.e. a simulated mechanical resistance. It is also desirable that this damping or mechanical resistance be made variable, i.e. that it be continuously adjusted to the current driving situation, the driver's driving style and/or the way he/she operates the gear lever. If the driver drives aggressively or changes gear very forcefully, the gear lever in known systems does not impart sufficient mechanical

resistance, so the driver may feel that the mechanism is too slack and perhaps defective, but if on the other hand the driver drives cautiously and does not apply so much force he/she may feel that the mechanical resistance in the gear lever is too great and that the gear lever is sluggish.

There does not seem to have been any previously known proposal of a gear lever or gear change mechanism which exerts an opposite force or damping in a gear lever in order to provide the driver with a good and appropriate gear change sensation in every position and thereby improve gear change work, e.g. in vehicles with electrically operated gear changing. Prior art thus does not solve these problems.

SUMMARY OF THE INVENTION

An object of the invention is to solve the above problems and propose a system and a method for control of a gear lever which provides the driver with a good, comfortable and

expected gear change sensation even when using an electronic gear lever, and which makes it easier for the vehicle's gear changes to take place correctly and with the right resistance and swiftness in relation to the current driving situation, the driver's driving style and/or the way he/she changes gear.

Another object of the invention is to apply to the gear lever a mechanical counterforce or damping which counteracts any excessively quick and/or forceful mechanical manual operation of the gear lever by the driver.

A further object of the invention is that the

counterforce/damping be adjusted to the current driving situation, the driver's driving style and/or the way he/she changes gear, i.e. that the counterforce/damping be made adaptive . These and further objects and advantages are achieved

according to the invention by a system according to the features indicated in the characterising parts of claims 1 and 6. The invention thus relates to a method and a system intended to provide a good and appropriate mechanical sensation when changing gear in a vehicle. This is particularly applicable for vehicles with electrically operated gear changing and with electronic gear levers, as in the case of "EC Shift" (a Scania system) . Achieving this entails the application of a

damping/counterforce which may be provided by a hydraulically, pneumatically, electrically or electromagnetically controlled actuator by means of which the magnitude or strength of the damping/counterforce can be adjusted. Making the damping adaptive and adjusting it to the current driving situation, the driver's driving style and/or the way he/she changes gear makes it possible to achieve a good and comfortable sensation in the gear lever irrespective of the current driving

situation, the driver's driving style and/or the way he/she changes gear.

If the driver's driving style is aggressive, i.e. if he/she accelerates a great deal, maintains a high engine speed and accelerates powerfully, the counterforce or damping in the gear lever will be relatively large. If on the other hand the vehicle is driven at a relatively constant and low road speed and at a low engine speed and with a limited degree of

accelerator pedal depression, the driver may be assumed to drive gently, with slow and cautious gear change movements, in which case the damping/counterforce in the gear lever may be relatively limited.

The counterforce or damping in the gear lever may also be adjusted to the current driving situation, e.g. the

counterforce or damping may be increased somewhat when driving in hilly terrain and/or where there are many bends and/or dense traffic and/or many variations in speed limits.

Conversely, the counterforce or damping in the gear lever may also be reduced somewhat in calmer circumstances, e.g. on level roads and/or where there are few bends and/or less traffic and/or few variations in speed limits. The current driving situation may also be detected on the basis of the vehicle's operating parameters, e.g. large steering wheel deflections may be taken to mean that the current driving situation involves many bends where the counterforce or damping in the gear lever will be increased.

Adaptiveness is therefore achievable by taking into account the vehicle's road speed, engine speed, GPS data, traffic information, topology etc. The calculation and the logic for the magnitude of the damping/counterforce may be conducted in a separate ECU for gear lever damping or be integrated in a control unit of some other system situated in the vehicle. The information about vehicle speed, engine speed, accelerator pedal position etc. may for example be obtained via the vehicle's CAN system or via discrete signals from sensors specifically provided for the purpose. Acceleration,

retardation etc. may also be calculated by means of existing signals in the vehicle, and certain information such as topology and/or traffic information is obtainable via GPS. The damping/counterforce in the gear lever is particularly intended for drivers who have a more aggressive driving style and who may therefore handle the gear lever too forcefully.

Further features and advantages of the invention are indicated by the more detailed description of it set out below and the accompanying drawings and other claims .

BRIEF LIST OF DRAWINGS

The invention is described in more detail below in the form of preferred embodiment examples with reference to the attached drawings .

Figure 1 is a schematic block diagram of the system according to the invention comprising an actuator/damping unit here controlled by means of a fluid in order to exert a suitable damping/counterforce in a gear lever.

Figure 2 is a further schematic block diagram with an

alternative actuator consisting here of an electromagnetic device .

Figure 3 is a flowchart of the method according to the

invention .

DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention thus relates to a method for effecting gear changes and to a gear change mechanism for a vehicle, particularly for a heavy commercial vehicle, e.g. a truck etc. The invention relates in particular to a method and a gear change mechanism which improve the gear change process and which adjust the mechanical resistance in the gear lever to the current driving situation, the driver' s driving style and/or the way he/she changes gear, so that the gear lever movement is braked/damped if, for example, the driver operates the gear lever too forcefully and/or changes gear too quickly.

Figure 1 depicts in more detail the general form of a system according to the invention. A gear lever 1 is limitedly pivotable about an articulation 2. A position sensor 3 provided in the lower portion of the gear lever 1 may for example be of inductive configuration. This position sensor 3 detects which position the gear lever 1 is in and hence which gear is engaged in a mechanical or semi-mechanical gearbox 4. If the gear lever 1 is moved in one direction or another, the position sensor 3 therefore indicates which new gear is to be engaged in the gearbox 4 and hence which gear the driver wishes to engage. A control signal SI is transmitted from the position sensor 3 to an electronic control unit 5 which controls a group of electric solenoid valves 6 which, by means of a fluid under pressure in a fluid tank 7, here containing compressed air, govern, via a cylinder 8, which gear is to be engaged in the gearbox 4. The number of solenoid valves in the group of valves 6 depends on how many movements need to be effected in the gear shifter. Two solenoid valves may create a reciprocating movement. A sensor 9 detects the position of the gear shifter 10, making it possible to determine which gear is engaged in the gearbox 4. The technology of engaging a certain gear according to this system is prior art and is not described in more detail here.

An actuator 11, here in the form of a pneumatic cylinder, is mechanically connected, via a further articulation 12, to the gear lever 1, more specifically in the region below the articulation 2. The actuator 11 may also comprise other types of units controlled by fluid or by electrical means, and may for example take the form of any positioner available on the market. The cylinder is here connected by fluid lines 13, 14 to a further solenoid valve 15 which in this case is provided with a proportional function and which can, by means of the pressurised fluid in the tank 17, direct the piston rod and cylinder to various positions on the basis of an electrical signal S2, or pulse with variable pulse width, from a

detection and/or calculation unit 18, preferably an ECU

(electronic control unit) . The proportional solenoid valve 15 may for example deliver from the tank 17 to the actuator 11 a pneumatic pressure, an air pressure, which is directly

proportional to the voltage or pulse width of the signal S2.

The ECU 18 may take the form of a separate electronic

processor-controlled unit in the vehicle, intended for the gear lever damping, but may also be part of, or integrated in, an ECU already present in the vehicle and intended to control one or other of the vehicle's other systems. Such control systems may be of the COO (Coordinator) type, gearbox control units or the like. With a view to achieving appropriate damping in the gear lever 1, a throttle valve 19 may also be provided between the lines 13 and 14 to allow the gear lever 1 to be moved against a force even without direct involvement of the solenoid valve 15.

The ECU 18 delivers a signal S2 to the solenoid valve 15 which thus determines to what extent the gear lever 1 is damped or acted upon. The signal S2 is calculated on the basis of, for example, current operating parameters Pi-P_n for the vehicle. These operating parameters Pi-P_n are for example obtained from the vehicle's CAN (controller area network) communication (not depicted) or via discrete signals from various sensors (not depicted) in the vehicle, or in some other suitable known way. Examples of such conceivable operating parameters Pi-P_n comprise engine speed, vehicle speed, accelerator pedal position/degree of accelerator pedal depression, how often and how forcefully the brake pedal is depressed, the vehicle's current weight, its levelness, GPS data, ESP information, the steering wheel's movements/steering angle, cooling water temperature, acceleration, retardation etc. One or more of these operating parameters Pi-P_n are supplied as input signal S3 to the ECU 18 and used as input data for calculations by means of one or more algorithms in the ECU 18 to produce the output signal S2. Acceleration, retardation etc. may also be worked out from other existing input signals, and certain information is also obtainable via GPS, e.g. if it is

desirable to control the gear lever damping in relation to local topography.

On the basis of that input signal S2, the cylinder 11

therefore brakes/damps the movements of the gear lever 1, e.g. if the ECU 18 detects the driver applying too much manual force to the gear lever 1 in relation to the operating

parameter values Pi-P_n which constitute the input signal S3 to the ECU 18. The force F indicated in Figure 1 thus represents the force which the system exerts on the gear lever 1, e.g. in the form of a damping or counterforce, in order to achieve correct and comfortable gear change irrespective of the current driving situation, the driver's driving style and/or the way he/she changes gear, i.e. the force F is adjusted and becomes

adaptive .

Figure 2 depicts an alternative embodiment of the invention in which the counterforce or damping in the gear lever 1 is provided by means of an electromagnetic actuator 20 which is electrically connected to the ECU 18. The electromagnetic actuator 20, which may also be an electric positioning motor or the like, thus replaces a hydraulic or pneumatic actuator but is similarly connected mechanically to the gear lever via an articulation 12 situated on the gear lever 1 below the articulation 2. The electromagnetic actuator 20 applies a braking force F by electromagnetic means. It is also possible to use two or more actuators which cooperate mechanically.

Figure 3 is a flowchart of the various steps of the method according to the invention. At step one, various parameter values needed for the calculation process are obtained via the vehicle's CAN communication or in some other suitable way. As mentioned above, examples of such operating parameters

comprise engine speed, vehicle speed, accelerator pedal position/degree of accelerator pedal depression, how often and how forcefully the brake pedal is depressed, the vehicle's current weight, its levelness, GPS data, topology, traffic information, ESP information, the steering wheel's

movements/steering angle, cooling water temperature,

acceleration, retardation etc.

At step two, the current driving situation, the driver's driving style and/or the way he/she changes gear are

identified by supplying to the ECU 18 and using as input data one or more of the parameters obtained at step one. The identification is effected by means of suitable algorithms which are not described in more detail. For example, driving at high engine speed may result in the driver' s current driving style being identified as aggressive.

At step three, a desired value, a set-point value, for the counterforce/damping which is to be applied to the gear lever is calculated on the basis of the current driving situation, the driver's driving style and/or the way he/she changes gear as identified at step two. At step four, the value calculated at step three is supplied, in the form of the control signal S2, to the actuator 11 which thereupon, at step five, exerts the counterforce/damping on the gear lever 1 by mechanical means to adjust the movements of the gear lever 1 in relation to the driver' s driving style and/or the way he/she changes gear.

The above description is primarily intended to facilitate comprehension of the invention. Accordingly, the invention is of course not limited to the embodiments indicated, since other variants of it are also possible and conceivable within the scope of the inventive concept and the protective scope of the claims set out below.

Thus it is also conceivable that the method and the system according to the invention may exert a negative damping, i.e. an active mechanical auxiliary force, on the gear lever to facilitate the driver's gear change work if he/she changes gear slowly and/or applies little mechanical force. The device will thus help to pull or push the gear lever into position and thereby servo-assist the driver if for any reason he/she cannot exert sufficient force on the gear lever. The invention is of course applicable in all types of vehicles which have electrically operated gear changing, hence also in passenger cars.

Claims

1. A method for adjusting the mechanical damping or

counterforce in a gear lever (1) in a vehicle to the current driving situation, the driver's driving style and/or the way he/she changes gear,

characterised by the method steps of

- detecting the current driving situation, the driver' s driving style and/or the way he/she changes gear,

- calculating on the basis of the current driving situation, the driver's driving style and/or the way he/she changes gear an instantaneous value for a mechanical damping/counterforce (F) desired in the gear lever (1), and

- using the calculated instantaneous value as a basis for causing an actuator (11, 20) to exert the desired

damping/counterforce (F) in the gear lever (1) and thereby adjust the damping/counterforce (F) of the gear lever (1) in relation to the current driving situation, the driver' s driving style and/or the way he/she changes gear.

2. A method according to claim 1,

characterised by the further method step of obtaining one or more operating parameter values Pi-P_n for

calculating/identifying the current driving situation, the driver's driving style and/or the way he/she changes gear.

3. A method according to claim 1 or 2,

characterised by the further method step of obtaining one or more operating parameter values Pi^~P_n from among the group of parameters which comprises engine speed, vehicle speed, accelerator pedal position/degree of accelerator pedal depression, brake pedal activities, vehicle weight, the vehicle's levelness, GPS data, ESP information, the steering wheel's movements/steering angle, cooling water temperature, acceleration, retardation.

4. A method according to any one of the foregoing claims, characterised by the further method step of exerting a negative force/damping, i.e. an assisting active mechanical auxiliary force, in the gear lever (1) to assist the driver's gear change work.

5. A method according to any one of the foregoing claims, characterised by the further method step of calculating acceleration and/or retardation on the basis of other

operating parameter values Pi-P_n, e.g. GPS data.

6. A system for adjusting the mechanical damping or

characterised

- in that a detection unit (18) is adapted to detecting the current driving situation, the driver's driving style and/or the way he/she changes gear,

- that a calculation unit (18) is adapted to calculating on the basis of the current driving situation, the driver' s driving style and/or the way he/she changes gear an

instantaneous value for a mechanical damping/counterforce (F) desired in the gear lever (1), and

- that an actuator (11, 20) is adapted to using the calculated instantaneous value as a basis for causing the actuator (11, 20) to exert the desired damping/counterforce (F) in the gear lever (1) and thereby adjust the damping/ counterforce (F) of the gear lever (1) to the current driving situation, the driver's driving style and/or the way he/she changes gear.

7. A system according to claim 6,

characterised in that the actuator (11, 20) takes the form of a hydraulic or pneumatic cylinder.

8. A system according to claim 6 or 7,

characterised in that the actuator (11, 20) is regulated by means of an electromagnetic valve (15) .

9. A system according to claim 6,

characterised in that the actuator (11, 20) functions

electromagnetically and may for example take the form

electric motor.