DRIVING OF A VEHICLE

TECHNICAL FIELD The invention relates to a method for controlling the driving of a vehicle according to the preamble of claim 1. The invention relates to a system for controlling the driving of a vehicle according to the preamble of claim 8. The invention relates also to a motor vehicle. The invention also relates to a computer programme and a computer programme product. BACKGROUND

Certain vehicles such as road freight vehicles are provided with different vehicle modes, comprising performance mode in which operability is given priority and fuel economy is subordinate, and economy mode In which priority is given to economical operation. Performance mode whereby operability is prioritised over fuel economy works for example well In forest road driving but is less appropriate from a fuel economy perspective in national highway and motorway driving.

One problem is for example that haulage of timber often starts in arduous off- road conditions where performance mode is suitable because operability is central, but often moves on to a national highway or motorway, and if the driver forgets to select economy mode with a view to economical operation the vehicle's fuel economy will be impaired.

OBJECTS OF THE INVENTION

One object of the present invention is to propose a method for controlling the driving of a vehicle which makes it possible to optimise fuel consumption without hampering operability. One object of the present invention is to propose a system for controlling the driving of a vehicle which makes it possible to optimise fuel consumption without hampering operabllity.

SUMMARY OF THE INVENTION These and other objects Indicated by the description set out below are achieved by a method, a system, a motor vehicle and a computer programme and a computer programme product of the kinds indicated in the Introduction which further present the features Indicated In the characterising parts of the attached independent claims 1 , 8, 15, 16 and 17. Preferred embodiments of the method and the system are defined In the attached dependent claims 2-7 and 9-14.

The invention achieves the objects with a method for controlling the driving of a vehicle, vehicle which can be run In at least one mode focused on operability and at least one mode focused on economical operation and be switched between said modes, which method comprises the steps of continuously determining a torque offtake pattern over a given period of time, of determining the proportion of said period during which the vehicle runs with a torque offtake which is either above a predetermined value or below a predetermined value, and of using said proportion as a basis for deciding whether the current mode Is the most appropriate. Information thus obtained makes It possible to optimise the driving of the vehicle by continually being able to run it in the mode most appropriate to prevailing circumstances. Optimisation of fuel consumption is thus made possible without hampering operability. In one embodiment the method further comprises the step of suggesting that the driver of the vehicle change mode if the current mode is not judged to be the most appropriate. This results in the driver being made aware that a change of mode might be appropriate and In consequent minimisation of the risk of a change of mode being missed through driver oversight. It also makes it possible for the driver to assess for him/herself whether the proposed change of mode Is correct and to choose whether to change mode or refrain from doing so.

In one embodiment the method further comprises the step of automatically changing mode If the current mode is Judged to be not the most appropriate, thus ensuring that the vehicle will run In the most appropriate mode.

In one embodiment the method further comprises the steps of continuously determining the vehicle's average speed over said given period of time, and whether said average speed is above a predetermined value. Suitable information is thus obtained for determining whether change of mode Is appropriate and whether a suggestion for change of mode should be presented for the driver.

In one embodiment the method further comprises the steps of continuously determining the vehicle's current speed and whether it is above a predetermined value. Suitable information is thus obtained for determining whether change of mode is appropriate and whether a suggestion for change of mode should be presented for the driver.

In one embodiment the method further comprises the step of continuously determining whether the vehicle is running with a torque offtake which Is above said predetermined value. Suitable information Is thus obtained for determining whether change of mode is appropriate and whether a suggestion for change of mode should be presented for the driver.

In one embodiment of the method no change of mode is suggested if said average speed Is not above said predetermined value and/or said current speed is not above said predetermined value and/or the vehicle is running with a torque offtake which is above said predetermined value. Presentation of a suggestion for change of mode is thus prevented if change of mode is not appropriate. The invention achieves the objects with a system for controlling the driving of a vehicle, which vehicle can be run in at least one mode focused on operability and at least one mode focused on economical operation and be switched between said modes, which system comprises means for continuously determining a torque offtake pattern over a given period of time, means for determining the proportion of said period during which the vehicle runs with a torque offtake which Is either above a predetermined value or below a predetermined value, and means for using said proportion as a basis for deciding whether the current mode is the most appropriate. Information thus obtained makes it possible to optimise the driving of the vehicle by continually being able to run it in the mode most appropriate to prevailing circumstances. Optimisation of fuel consumption is thus made possible without hampering operability.

In one embodiment the system further comprises means for suggesting that the driver of the vehicle change mode if the current mode is not judged to be the most appropriate. This results in the driver being made aware that a change of mode might be appropriate and in consequent minimisation of the risk of a change of mode being missed through driver oversight. It also makes It possible for the driver to assess for him/herself whether the proposed change of mode is correct and to choose whether to change mode or refrain from doing so,

In one embodiment the system further comprises means for automatically changing mode if the current mode is judged to be not the most appropriate., thus ensuring that the vehicle will run in the most appropriate mode. In one embodiment the system further comprises means for continuously determining the vehicle's average speed over said given period of time, and means for determining whether said average speed is above a predetermined value. Suitable Information Is thus obtained for determining whether change of mode is appropriate and whether a suggestion for change of mode should be presented for the driver. In one embodiment the system further comprises means for continuously determining the vehicle's current speed and means for determining whether it is above a predetermined value. Suitable information is thus obtained for determining whether change of mode is appropriate and whether a suggestion for change of mode should be presented for the driver.

In one embodiment the system further comprises means for continuously determining whether the vehicle is running with a torque offtake which is above said predetermined value. Suitable information Is thus obtained for determining whether change of mode is appropriate and whether a suggestion for change of mode should be presented for the driver.

In one embodiment of the system no change of mode is suggested if said average speed is not above said predetermined value and/or said current speed is not above said predetermined value and/or the vehicle is running with a torque offtake which is above said predetermined value. Presentation of a suggestion for change of mode is thus prevented if change of mode Is not appropriate.

DESCRIPTION OF DRAWINGS

The present invention will be better understood by reading the detailed description set out below in conjunction with the attached drawings, In which the same reference notations are used for similar items throughout the various views, and

Fig. 1 schematically illustrates a motor vehicle according to an embodiment of the present invention,

Fig. 2 schematically illustrates a system for controlling the driving of a vehicle according to an embodiment of the present invention,

Fig. 3 schematically illustrates a torque offtake pattern during vehicle driving over a period of time according to an embodiment of the present invention, Fig. 4 is a schematic block diagram of a method for controlling the driving of a vehicle according to an embodiment of the present invention, and

Fig. 5 schematically illustrates a computer according to an embodiment of the present invention. DESCRIPTION OF EMBODIMENTS

The term "link" refers herein to a communication link which may be a physical connection such as an opto-electronic communication line, or a non-physical connection such as a wireless connection, e.g. a radio link or microwave link.

Fig. 1 illustrates schematically a motor vehicle 1 according to an embodiment of the present invention. The vehicle exemplified is a heavy vehicle In the form of a truck but might alternatively be any suitable vehicle, e.g. a bus or a car. The vehicle Is provided with a system I according to the present invention.

Fig. 2 is a schematic block diagram of a system I for controlling the driving of a vehicle according to an embodiment of the present invention.

The system I comprises an electronic control unit 100 for said controlling.

The system I comprises torque determination means 110 for continuously determining the vehicle's propulsive torque, i.e. the propulsive torque extracted from the vehicle's engine, in order to determine a torque offtake pattern over a given period of time. Said means 110 comprises any suitable means for determining the vehicle's propulsive torque and comprises in one variant sensor means for determining amounts of fuel injected and/or a torque meter.

The system I comprises speed determination means 120 for continuously determining the vehicle's speed in order to determine its average speed over a given period of time. Said means 120 comprises In one variant speedometer means. The system I further comprises vehicle mode determination means 130 for determining which mode the vehicle is in from among modes comprising a mode focused on operability, herein called performance mode, in which fuel economy Is subordinate, and a mode focused on economical operation, herein called economy mode. Said means 130 comprises in one variant gear position monitoring means and power output monitoring means for monitoring the engine's power output, and said mode focused on operability Is Identified if the gear position monitoring means finds that the transmission is in a relatively lower gear position such that there is higher power output in the engine, and economy mode is identified if the gear position is suited to low fuel consumption.

The system I further comprises action suggestion presentation means 1 0 for presenting the driver with suggestions for action which comprises change of the vehicle's mode if the current mode is judged to be not the most appropriate. Said means 140 may comprise any suitable means for presenting suggestions for action, comprising means for visual presentation such as continuous or flashing lights indicating suggested action, and/or text and/or symbols indicating suggested action, means for auditory presentation comprising alarms and/or voice presentation of suggested action, means for tactile information comprising vibrations or the like which indicate suggested action. Said means 140 comprise in one variant a vehicle display unit situated in the vehicle's instrument cluster to present said suggestions for action, i.e. suggesting change of mode if the current mode is judged to be not the most appropriate. The electronic control unit 100 Is signal-connected to said torque determination means 110 via a link 10 enabling it to receive from said means 1 0 a signal which represents data on propulsive torque extracted.

The electronic control unit 100 is signal-connected to said speed determination means 120 via a link 20 enabling it to receive from said means 120 a signal which represents data on the vehicle's speed. The electronic control unit 100 is signal-connected to said vehicle mode determination means 130 via a link 30 enabling it to receive from said means 130 a signal which represents data on which mode the vehicle is in, i.e. performance mode or economy mode. The electronic control unit 100 Is signal-connected to said action suggestion presentation means 140 via a link 40 enabling It to send to said means 140 a signal which represents action suggestion data for presenting the driver with suggestions for action which comprises change of mode.

The electronic control unit 100 is adapted to processing said torque data from the torque determination means 110 in order to determine a torque offtake pattern continuously over a given period of time. It is adapted to determining the proportion of said period of time during which the vehicle runs with a torque offtake which Is either above a predetermined, value or below a predetermined value. Fig. 3 Illustrates an example of a torque offtake pattern determined over a given period of time.

The electronic control unit 100 is adapted to processing said data on which mode the vehicle Is In from said vehicle mode determination means 130, to comparing with the proportion of said period of time determined as that during which the vehicle runs with a torque offtake which is either above a predetermined value or below a predetermined value, and to using said proportion as a basis for deciding whether the current mode is the most appropriate.

The electronic control unit 100 is adapted to sending to said action suggestion presentation means 1 0 via the link 40 a signal which represents action suggestion data for presenting the driver with suggestions for action for change of mode if the current mode is judged to be not the most appropriate.

The electronic control unit comprises in one variant means for automatic change of mode If the current mode Is judged to be not the most appropriate. The electronic control unit 100 is adapted to processing said torque data in order to determine continuously whether the vehicle is running with a torque offtake which is above said predetermined value in cases where change of mode is not suggested and said action suggestion presentation means 140 is therefore not sent any signal suggesting change of mode if the vehicle is running with a torque offtake which is above said predetermined value. In the case of automatic change of mode, no change takes place if the vehicle is running with a torque offtake which is above said predetermined value.

The electronic control unit 100 is adapted to processing said speed data from the speed determination means 120 in order to determine the vehicle's average speed over a given period of time. It is adapted to determining whether said average speed is above a predetermined value in cases where change of mode is not suggested and said action suggestion presentation means 140 is therefore not sent any signal suggesting change of mode if said average speed Is not above said predetermined value. In the case of automatic change of mode, no change takes place if said average speed is not above said predetermined value.

The electronic control unit 100 is adapted to processing said speed data from the speed determination means 120 in order to determine the vehicle's current speed continuously over a given period of time. It is adapted to determining whether said current speed Is above a predetermined value in cases where change of mode is not suggested and said action suggestion presentation means 140 is therefore not sent any signal suggesting change of mode if said current speed is not above said predetermined value. In the case of automatic change of mode, no change takes place If said current speed is not above said predetermined value,

The electronic control unit comprises in one variant means for automatic change of mode If the current mode Is Judged to be not the most appropriate. Fig, 3 illustrates schematically a torque offtake pattern during driving of a vehicle over a period of time according to an embodiment of the present invention.

In the case exemplified, the vehicle travels along an itinerary and a torque offtake pattern is determined over a period between time ti and time t ₂ by means of said electronic control unit 100 as described above In relation to Fig. 2.

The vehicle travels from time t| for a first part-period (i) during which It runs with a torque offtake which Is above a predetermined upper value M _ma * and might represent torque offtake when travelling uphill and/or heavily laden.

The vehicle travels for a second part-period (II) during which it runs with a torque offtake which is between said predetermined upper value M _max and a predetermined lower value _m i _n such that part-period (ii) here represents a transition between M _max and M _m i _n , herein called torque offtake at partial load, Mp, and Is relatively short and might be at the transition between an upgrade where maximum torque offtake Is required and a downgrade where minimum torque offtake, so-called drag torque, is required.

The vehicle proceeds further during a third part-period (III) In which It runs with a torque offtake which is below said predetermined lower value M _m in and might represent downhill driving.

The vehicle travels for a fourth part-period (iv) during which it runs with a torque offtake M _p which is between said predetermined upper value M _max and said predetermined lower value M _m i _n and might represent travelling on a substantially level road at above a certain speed, as on a national highway or motorway.

The vehicle travels for a fifth part-period (v) during which it runs with a torque offtake which is above said predetermined upper value M _m3X until a time t ₂ . The electronic control unit 100 is adapted to determining the proportion of said period of time during which the vehicle runs with a torque offtake which is either above a predetermined value or below a predetermined value. This is achieved by the part-periods during which the torque offtake is above the upper value M _max , I.e. (I) and (v), and those during which the torque offtake is below the lower value M _m i _n> I.e. (Ill), being added together and divided by the whole period, I.e. (i) + (ii) + (III) + (Iv) + (v). The proportion of said period during which the vehicle runs with a torque offtake which is either above said predetermined upper value M _ma x or below said predetermined lower value Mmin is then arrived at as a ratio Q which in the example In Fig. 3 will be Q = ((i) + (v) + (iii)) / ((i) + (ii) + (ii«) + (iv) + (v)).

The period M2 in one embodiment is of the order of two minutes.

Torque offtake at part-load in one variant is within the range of 10-80% of the maximum torque offtake. The ratio Q between the part-periods in which the vehicle runs at above M _ma x or below M _m ir> and the total period determines accordingly whether the current mode in which the vehicle is running Is the most appropriate. If Q is below a predetermined threshold value and the current mode Is performance mode, this will not be deemed the most appropriate mode and a change to economy mode will be suggested to the driver via said action suggestion presentation means 140, subject to maintaining a certain average speed which is above a predetermined level.

Said threshold value in one variant Is within the range 0-30%.

Fig. 4 is a schematic block diagram of a method for controlling the driving of a vehicle according to an embodiment of the present invention.

In one embodiment the method for controlling the driving of a vehicle comprises a first step S1 of determining a torque offtake pattern continuously over a given period of time. In one embodiment the method for controlling the driving of a vehicle comprises a second step S2 of determining the proportion of said period during which the vehicle runs with a torque offtake which is either above a predetermined value or below a predetermined value. In one embodiment the method for controlling the driving of a vehicle comprises a third step S3 of deciding on the basis of said proportion whether the current mode is the most appropriate.

Fig. 5 is a diagram of one version of a device 500. The control unit 100 described with reference to Figure 2 may in one version comprise the device 500. The device 500 comprises a non-volatile memory 520, a data processing unit 510 and a read/write memory 550. The non-volatile memory has a first memory element 530 in which a computer programme, e.g. an operating system, is stored for controlling the function of the device 500. The device 500 further comprises a bus controller, a serial communication port, I/O means, an A/D converter, a time and date input and transfer unit, an event counter and an interruption controller (not depicted). The non-volatile memory has also a second memory element 540.

A proposed computer programme P comprises routines for controlling the driving of a vehicle according to the innovative method. The programme comprises routines for determining a torque offtake pattern continuously over a given period of time. It comprises routines for determining the proportion of said period during which the vehicle runs with a torque offtake which is either above a predetermined value or below a predetermined value. It comprises routines for using said proportion as a basis for deciding whether the current mode Is the most appropriate. The programme P may be stored in an executable form or in compressed form in a memory 5Θ0 and/or in a read/write memory 550.

Where the data processing unit 510 is described as performing a certain function, It means that It conducts a certain part of the programme stored in the memory 560 or a certain part of the programme stored in the read/write memory 550.

The data processing device 510 can communicate with a data port 599 via a data bus 515. The non-volatile memory 520 is intended for communication with the data processing unit 510 via a data bus 512. The separate memory 560 is intended to communicate with the data processing unit via a data bus 511. The read/write memory 550 Is adapted to communicating with the data processing unit via a data bus 5 . The links associated for example with the control unit 100 may be connected to the data port. When data are received on the data port 599, they are stored temporarily In the second memory element 540. When input data received have been temporarily stored, the data processing unit 510 is prepared to conduct code execution as described above. The signals received on the data port may be used by the device 500 to determine a torque offtake pattern continuously over a given period of time. The signals received on the data port may be used by the device 500 to determine the proportion of said period during which the vehicle runs with a torque offtake which is either above a predetermined value or below a predetermined value. The signals received on the data port may be used by the device 500 for using said proportion as a basis for deciding whether the current mode is the most appropriate.

Parts of the methods herein described may be conducted by the device 500 by means of the data processing unit 510 which runs the programme stored in the memory 560 or the read/write memory 550, When the device 500 runs the programme, methods herein described are executed. A method and a system for controlling the driving of a vehicle are described above whereby change of mode is suggested to the vehicle's driver if the current mode Is Judged to be not the most appropriate. In an alternative variant, change of mode takes place automatically if the current mode is judged to be not the most appropriate. The above description of the preferred embodiments of the present invention is provided for illustrative and descriptive purposes. It is not intended to be exhaustive, nor to restrict the invention to the variants described. Many modifications and variations will obviously suggest themselves to one skilled In the art. The embodiments have been chosen and described in order best to explain the principles of the invention and their practical applications and thereby make it possible for one skilled in the art to understand the invention for different embodiments and with the various modifications appropriate to the intended use.