WO2013191621A1

WO2013191621A1 - Method and system for velocity adaptation during forward travel of a motor vehicle

Info

Publication number: WO2013191621A1
Application number: PCT/SE2013/050681
Authority: WO
Inventors: Linus Bredberg; Jonny Andersson
Original assignee: Scania Cv Ab
Priority date: 2012-06-19
Filing date: 2013-06-12
Publication date: 2013-12-27

Abstract

The present invention concerns a method for velocity adaptation during the forward travel of a motor vehicle, comprising the step of retarding the vehicle by means of the engine brake of the vehicle by eliminating accelerator depression or by means of free running to achieve a determined lower velocity at a desired position, comprising the steps of: determining (S1), based on current conditions regarding the forward travel of the vehicle, the retardation of the vehicle under the action of said engine brake or free running; and deciding (S2), based on said determination, a position of the vehicle at which said elimination of accelerator depression or activation of free running is to occur. The present invention also concerns a system for velocity adaptation during the forward travel of a motor vehicle. The present invention also concerns a motor vehicle. The present invention further concerns a computer program and a computer program product.

Description

METHOD AND SYSTEM FOR VELOCITY ADAPTATION DURING FORWARD TRAVEL OF A MOTOR VEHICLE

TECHNICAL FIELD OF THE INVENTION The invention concerns a method for velocity adaptation during the forward travel of a motor vehicle according to the preamble to claim 1 . The invention also concerns a system for velocity adaptation during the forward travel of a motor vehicle according to the preamble to claim 8. The invention also concerns a motor vehicle. The invention further concerns a computer program and a computer program product.

BACKGROUND

Economical operation of motor vehicles is becoming increasingly important, in part for fuel savings. Predictive driver behavior in connection with, for example, a lower speed limit is important to the economical forward travel of the vehicle in this respect.

One typically good predictive driver behavior is that wherein the driver eliminates accelerator depression, i.e. releases the accelerator or cruise control, in order to achieve a lower velocity in connection with, for example, an imminent lower speed limit along the route of the vehicle with the need to use the foot brake or retarder.

One problem is that it can be difficult for the driver to estimate when the accelerator should be released. If, for example, a speed limit sign is concealed by a curve or crown along the route of the vehicle, it may be difficult to see the sign in time to achieve the correct velocity at the position of the lower speed limit by means of engine braking. OBJECT OF THE INVENTION

One object of the present invention is to achieve a method for velocity adaptation during the forward travel of a motor vehicle that results in fuel- efficient forward travel of the vehicle.

One object of the present invention is to achieve a system for velocity adaptation during the forward travel of a motor vehicle that results in fuel- efficient forward travel of the vehicle.

SUMMARY OF THE INVENTION These and other objects, which are specified in the description below, are achieved by means of a method and a system for velocity adaptation during the forward travel of a motor vehicle, a motor vehicle, a computer program and a computer program product of the types specified above, and which further exhibit the features specified in the characterizing part of accompanying independent claims 1 and 8. Preferred embodiments of the method and the system are defined in accompanying independent claims 2-7 and 9-14.

According to the invention, these objects are achieved by means of a method for velocity adaptation during the forward travel of a motor vehicle comprising the step of retarding the vehicle by means of the engine brake of the vehicle by eliminating accelerator depression or by means of free running in order to achieve a determined lower velocity at a desired position, and comprising the steps of: determining, based on current conditions regarding the forward travel of the vehicle, the retardation of the vehicle under the action of said engine brake or free running; and deciding, based on said determination, the position of the vehicle at which said the elimination of accelerator depression or the activation of free running is to occur. This enables fuel-efficient forward travel of a vehicle in that the desired velocity can be achieved at the desired position by utilizing the engine brake of the vehicle. Speed limits can thereby be obeyed in combination with fuel-efficient forward travel of the vehicle.

According to one embodiment of the method, said current conditions comprise the velocity of the vehicle. Determination of the desired position at which the determined lower velocity is to be achieved is thereby facilitated.

According to one embodiment of the method, said current conditions comprise at least one of the following parameters: vehicle mass, the gear that the vehicle transmission is in, topography along the route of the vehicle, engine rpm, air resistance, rolling resistance and wirelessly communicated outside information. Determination of the desired position at which the determined lower velocity is to be achieved is thereby facilitated.

According to one embodiment of the method, said desired position refers to the route of the vehicle and pertains, for example, to a lower speed limit, curves and the presence of speed cameras. Taking into account permissible lower speeds along the route facilitates compliance with speed limits for increased traffic safety. Taking into account curves along the route to enable suitable velocity reduction before the curve provides for increased traffic safety. Taking into account speed cameras along the route facilitates the avoidance of speeding. According to one embodiment, the method comprises the step of determining said desired position based on cartographic data and/or sensing by means of camera elements. Efficient determination of said desired position is thereby facilitated.

According to one embodiment of the method, said desired position refers to a desired distance to a preceding vehicle. Fuel-efficient adaptation to a preceding vehicle that is, for example, retarding and/or traveling at a lower velocity than the present vehicle is thereby facilitated. According to one embodiment, the method comprises the step of determining said desired position based on distance determining elements, such as radar elements or laser elements. Efficient distance determination is thereby enabled. According to the invention, these objects are achieved by means of a system for velocity adaptation during the forward travel of a motor vehicle, which system comprises means for retarding the vehicle by means of the engine brake of the vehicle by eliminating accelerator depression or by means of free running in order to achieve a determined lower velocity at a desired position, comprising means for determining, based on current conditions regarding the forward travel of the vehicle, the retardation of the vehicle under the action of said engine brake or free running; and means for deciding, based on said determination, a position of the vehicle at which said elimination of accelerator depression or activation of free running is to occur. Fuel-efficient forward travel of the vehicle is enabled thereby in that a desired velocity can be achieved at a desired position by utilizing the engine brake of the vehicle. Speed limits can be obeyed thereby in combination with fuel- efficient forward travel of the vehicle.

According to one embodiment of the system, said current conditions comprise the velocity of the vehicle. Deciding the desired position at which the determined lower velocity is to be achieved is thereby facilitated.

According to one embodiment of the system, said current conditions comprise at least one of the following parameters: vehicle mass, the gear that the vehicle transmission is in, topography along the route of the vehicle, engine rpm, air resistance, rolling resistance and wirelessly communicated outside information. Determination of the desired position at which the determined lower velocity is to be achieved is thereby facilitated. According to one embodiment of the system, said desired position refers to the route of the vehicle and pertains, for example, to a lower speed limit, curves or the presence of speed cameras. Taking into account permissible lower speeds along the route facilitates compliance with speed limits for increased traffic safety. Taking into account curves along the route to enable suitable velocity reduction before the curve provides for increased traffic safety. Taking into account speed cameras along the route facilitates the avoidance of speeding.

According to one embodiment, the system comprises the step of determining said desired position based on cartographic data and/or sensing by means of camera elements. Efficient determination of said desired position is thereby facilitated.

According to one embodiment of the system, said desired position refers to a desired distance to a preceding vehicle. Fuel-efficient adaptation to a preceding vehicle that is, for example, retarding and/or traveling at a lower velocity than the present vehicle is thereby facilitated.

According to one embodiment, the system comprises means for determining said desired position based on distance determining elements, such as radar elements or laser elements. Efficient distance determination is thereby enabled.

FIGURE DESCRIPTION

The present invention will be better understood with reference to the following detailed description read together with the accompanying drawings, wherein the same reference designations consistently refer to the same parts in the multiple views, and in which:

Fig. 1 schematically illustrates a motor vehicle according to one embodiment of the present invention; Fig. 2 schematically illustrates a system for velocity adaptation during the forward travel of a motor vehicle according to one embodiment of the present invention;

Fig. 3 schematically illustrates a block diagram of a method for velocity adaptation during the forward travel of a motor vehicle according to the present invention; and

Fig. 4 schematically illustrates a computer according to one embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

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

The term "free running" refers here to when the vehicle transmission is in neutral, so that the engine runs at idle. "Activation of free running" refers to shifting the gears to neutral.

Fig. 1 schematically illustrates a motor vehicle 1 according to one embodiment of the present invention. The exemplary vehicle 1 consists of a heavy vehicle in the form of a goods vehicle. The vehicle can alternatively consist of any suitable vehicle, such as a bus or a car. The vehicle contains a system according to the present invention.

Fig. 2 schematically illustrates a block diagram of a system I for velocity adaptation during the forward travel of a motor vehicle according to one embodiment of the present invention. The system comprises an electronic control unit 100 for said determination. The system I comprises velocity change determining means 1 10 for determining a velocity change necessary to achieve a determined lower velocity at a desired position.

Said velocity change determining means 1 10 comprise camera elements 1 12. The system I consequently comprises camera elements 1 12 for determining a velocity change necessary to achieve a determined lower velocity at a desired position. Said camera elements 1 12 are arranged so as to detect speed limit signs along the route of the vehicle in order to identify velocity changes along the route. Said camera elements 1 12 according to one variant are arranged so as to detect other objects along the vehicle route in addition to speed limit signs, such as any impediments to forward travel along the vehicle route, such as cyclists, pedestrians, wild animals, fallen trees or the like.

Said velocity change determining means 1 10 comprise route determining means 1 14. The system I consequently comprises route determining means 1 14 for determining a velocity change needed to achieve a determined lower velocity at a desired position. Said route determining means 1 14 are arranged so as to provide predetermined characteristics of the roadway along the vehicle route and the position of the vehicle along the vehicle route. According to one variant, said route determining means 1 14 comprise a cartographic information unit 1 14a containing cartographic data including said characteristics of the roadway along the vehicle route at a position at which a lower velocity is needed, such as velocity changes in the form of a lower speed limit along the vehicle route, curves along the vehicle route, or exits along the vehicle route, in order to thereby determine a velocity change needed to achieve a determined lower speed at a desired position. The cartographic information unit 1 14a also provides information regarding the topography along the vehicle route. According to one variant, the cartographic information unit 4a further provides information about the roadbed, such as a paved road or gravel road, which affects the rolling resistance of the vehicle.

Said route determining means 1 14 further comprise vehicle position determining means 1 14b in the form a geographic positioning system, i.e. GPS, for identifying the position of the vehicle relative to the position at which a lower velocity is needed.

The route determining means 1 14, i.e. the cartographic information unit 1 14a and the vehicle position determining means 1 14b, consequently make it possible to determine the position at which a lower velocity is needed, as well as the position of the vehicle relative to the position at which a lower velocity is needed.

Said velocity change determining means 1 10 comprise distance determining means 1 16 for determining the velocity change needed to achieve a determined lower velocity at a desired position. Said distance determining means 1 16 are configured so as to continuously determine distances between the vehicle and a preceding vehicle or corresponding object, as well as the relative velocity between the vehicle and a preceding vehicle in order to thereby determine the velocity change needed. The system I consequently comprises distance determining means 1 16. According to one variant, said distance determining means 1 16 consist of a radar element and/or laser element.

The system I comprises forward travel conditions determining means 120 in order to determine, based on current conditions regarding the forward travel of the vehicle, the retardation of the vehicle under the action of the engine brake of the vehicle. Said conditions comprise the velocity of the vehicle. Said conditions further comprise at least one of the following parameters: vehicle mass, the gear that the vehicle transmission is in, topography along the route of the vehicle, engine rpm, air resistance, rolling resistance and wirelessly communicated outside information. According to one variant, said forward travel conditions determining means 120 comprise velocity determining means 121 for determining the vehicle velocity in order to know the necessary velocity decrease. According to one variant, said velocity determining means 121 comprise velocity measuring elements.

According to one variant, said forward travel conditions determining means 120 comprise communications means 122 for wireless communication between vehicles and/or communication with infrastructure. According to one variant, said communication means 122 comprise communication pertaining to outside information, including weather information such as the wind force and wind direction, current precipitation, and the traffic situation, such as temporary speed restrictions due to a traffic accident or the like. According to one variant, said communication means 122 comprise a radio unit and/or so- called wireless LAN or WLAN in order in part to determine the weather situation so as, based in part on weather information, to determine the retardation of the vehicle under the action of the engine brake of the vehicle.

Said forward travel conditions determining means 120 further comprise vehicle weight determining means 123 for determining the vehicle mass, i.e. the weight of the vehicle including the vehicle load. Said vehicle weight determining means 123 can comprise any suitable weight sensor elements.

Said forward travel conditions determining means 120 further comprise accelerator depression determining means 124 for determining the current accelerator depression for the accelerator element of the vehicle, such as a gas pedal. Said accelerator depression determining means 124 can comprise any suitable sensor elements for determining the degree of accelerator depression, such as sensor elements for sensing the gas pedal position.

Said forward travel conditions determining means 120 further comprise braking determining means 125 for determining the current braking by means of the vehicle foot brake elements and/or retarder elements, wherein the foot brake elements according to one variant comprise a brake pedal. Said braking determining 125 can comprise any suitable sensor elements for determining the degree of braking by means of foot brake elements and/or retarder elements, such as sensor elements for sensing the foot brake pedal position.

Said forward travel conditions determining means 120 further comprise engine rpm determining means 126 for determining the current engine rpm of the vehicle. Said engine rpm determining means 126 can comprise any suitable sensor elements for determining engine rpm, such as a tachometer element.

Said forward travel conditions determining means 120 further comprise gear determining means 127 for determining the current gear of the vehicle, including the neutral gear for free running. Said gear determining means 127 can comprise any suitable sensor elements for determining the current gear. Said forward travel conditions determining means 120 further comprise precipitation sensor elements 128 such as rain sensor elements for determining the current precipitation along the vehicle route.

Said system I further comprises rolling resistance determining means 130 for determining the rolling resistance of the vehicle. According to one variant, said rolling resistance determining means comprise vehicle-specific characteristics consisting of a rolling resistance constant, wherein the rolling resistance constant is determined by estimation, and/or by means of a learning process in which the actual rolling resistance is measured under specific conditions and compared with the estimated rolling resistance. According to one embodiment, said rolling resistance determining means 130 are comprised by said forward said travel conditions determining means 120.

Said system I further comprises air resistance determining means 140 for determining the current air resistance of the vehicle. According to one variant, said air resistance determining means comprise vehicle-specific characteristics consisting of an air resistance constant, wherein the air resistance constant is determined by estimation, and/or by means of a learning process wherein a measurement of the actual air resistance under specific conditions is made and compared with the estimated air resistance.

According to one embodiment, said air resistance determining means 140 are comprised by said travel conditions determining means 120.

The system I further comprises accelerator depression elimination informing means 150 for providing information as to when the elimination of accelerator depression is to occur to achieve a determined lower velocity at a desired position. Said accelerator depression elimination informing means 150 can comprise any suitable means for informing the driver that the elimination of accelerator depression is to occur, such as a display unit on which information is displayed, such as text, flashing, illuminated fields or the equivalent, by means of audio signals, by vibrations, automatically by acting upon the accelerator depression element or the like.

The system I further comprises free running activation informing means 155 for providing information as to when the activation of free running is to occur in order to achieve a determined lower velocity at a desired position. Said free running activation informing means 155 can comprise any suitable means for informing the driver that free running activation is to occur, such as a display unit on which the information is displayed as text, flashing, illuminated fields or the equivalent, by means of audio signals, by vibrations, automatically by acting upon the transmission or the like. The electronic control unit 100 is signal-connected to said velocity change determining means 1 10 via a link 10. The electronic control unit 100 is arranged via link 10 so as to receive a signal from the velocity change determining means 1 10 representing velocity change data for the velocity change needed to achieve a determined lower velocity at a desired position. The electronic control unit 100 is signal-connected to said camera element 1 12 via a link 12. The electronic control unit 100 is arranged via the link 12 so as to receive a signal from the camera element 1 12 representing object data comprising, according to one variant, speed limit informing data from speed limit signs for the velocity changed needed to achieve a determined lower velocity at the position of said speed limit.

The electronic control unit 100 is signal-connected to said route determining means 1 14 via a link 14. The electronic control unit 100 is arranged via the link 14 so as to receive a signal from the route determining means 1 14 representing route data comprising position data from the vehicle position determining means 1 14b and cartographic data comprising speed limit data from the cartographic information unit 1 14a for the velocity change needed to achieve a determined lower velocity at the position of said speed limit.

The electronic control unit 100 is signal-connected to said distance determining means 1 1 via a link 16. The electronic control unit 100 is arranged via the link 16 so as to receive a signal from the distance determining means 1 16 representing distance data for the distance to a preceding vehicle in order to determine the velocity change needed to achieve a determined lower velocity at a desired position relative to the preceding vehicle.

The electronic control unit 100 is signal-connected to said forward travel conditions determining means 120 via a link 20. The electronic control unit 100 is arranged via the link 20 so as to receive a signal from the forward travel conditions determining means 120 representing condition data pertaining to the forward travel of the vehicle in order to determine, based on current conditions, the retardation of the vehicle under the action of the engine brake of the vehicle.

The electronic control unit 100 is signal-connected to said velocity determining means 121 via a link 21 . The electronic control unit 100 is arranged via the link 21 so as to receive a signal from said velocity determining means 121 representing velocity data for the vehicle in order to know the velocity reduction needed to achieve the desired velocity.

The electronic control unit 100 is signal-connected to said communication means 122 via a link 22. The electronic control unit 100 is arranged via the link 22 so as to receive a signal from said communication means 122 representing weather data for determining the wind direction and/or precipitation in order to determine the retardation of the vehicle under the action of the engine brake of the vehicle. The electronic control unit 100 is signal-connected to said vehicle weight determining means 123 via a link 23. The electronic control unit 100 is arranged via the link 23 so as to receive a signal from said vehicle weight determining means 123 representing vehicle weight data for determining the vehicle weight in order to determine the retardation of the vehicle under the action of the engine brake of the vehicle.

The electronic control unit 100 is signal-connected to said accelerator depression determining means 124 via a link 24. The electronic control unit 100 is arranged via the link 24 so as to receive a signal from said accelerator depression determining means 124 representing accelerator depression data.

The electronic control unit 100 is signal-connected to said braking determining means 125 via a link 25. The electronic control unit 100 is arranged via the link 25 so as to receive a signal from said braking determining means 125 representing braking data for the degree of braking by means of the foot brake and/or retarder.

The electronic control unit 100 is signal-connected to said engine rpm determining means 126 via a link 26. The electronic control unit 100 is arranged via the link 26 so as to receive a signal from said engine rpm determining means 126 representing engine rpm data. The electronic control unit 100 is signal-connected to said gear determining means 127 via a link 27. The electronic control unit 100 is arranged via the link 27 so as to receive a signal from said gear determining means 127 representing transmission data for the current gear of the vehicle transmission.

The electronic control unit 100 is signal-connected to said precipitation sensor element 128 via a link 28. The electronic control unit 1 00 is arranged via the link 28 so as to receive a signal from said precipitation sensor element 128 representing precipitation data. The electronic control unit 100 is signal-connected to said rolling resistance determining means 130 via a link 30. The electronic control unit 100 is arranged via the link 30 so as to receive a signal from said rolling resistance determining means 130 representing rolling resistance data.

According to one variant, said rolling resistance determining means 130 comprise said route determining means 1 14 comprising said cartographic information unit 1 14a wherein, according to one variant, the cartographic information unit provides information about the topography along the vehicle route in order to thereby determine the inclination of the road affecting the rolling resistance and, according to one variant, information about the roadbed, such as a paved road or gravel road, affecting the rolling resistance of the vehicle. According to one variant, said rolling resistance determining means comprise said communication means for wireless outside information comprising weather information about precipitation, whereupon current precipitation such as rain and/or snow is taken into account in determining the rolling resistance. According to one variant, said rolling resistance determining means comprise said precipitation sensor element to be taken into account in determining the rolling resistance. According to this variant, the electronic control unit 100 is arranged so as to receive rolling resistance data representing the actual rolling resistance of the vehicle at the current time point from said rolling resistance determining means 130, whereupon the rolling resistance is determined by said rolling resistance determining means 130 by processing said constant rolling resistance data with road inclination data and/or roadbed data from the route determining means 1 14 and/or weather data concerning precipitation from the communication means 122 and/or precipitation data from the precipitation sensor element 128.

According to one variant, the electronic control unit 100 is arranged so as to receive constant rolling resistance data from said rolling resistance determining means 130, and to process said constant rolling resistance data with said road inclination data and/or roadbed data and/or weather data and/or precipitation data.

The electronic control unit 100 is signal-connected to said air resistance determining means 140 via a link 40. The electronic control unit 100 is arranged via the link 40 so as to receive a signal from said air resistance determining means 140 representing rolling resistance data. According to one variant, said air resistance determining means comprise said communication means for wireless outside information comprising weather information regarding the wind force and wind direction, whereupon the current wind force and wind direction are taken into account in determining the air resistance. According to one variant, said air resistance determining means comprise said velocity determining means.

According to this variant, the electronic control unit 100 is arranged so as to receive air resistance data representing the actual air resistance for the vehicle at the current time point from said air resistance determining means 140, whereupon the air resistance is determined by said air resistance determining means 140 by processing said constant air resistance data with velocity data and, in applicable cases, weather data concerning the wind force and wind direction from the communication means 122 and/or precipitation data from the precipitation sensor element 128. According to one variant, the electronic control unit 100 is arranged so as to receive said constant air resistance data from said air resistance determining means 140 and process said constant air resistance data with said velocity data and, in applicable cases, weather data concerning the wind force and wind direction.

The electronic control unit 100 is signal-connected to said accelerator depression elimination informing means 150 via a link 50. The electronic control unit 100 is arranged via the link 50 so as to send a signal to said accelerator depression elimination informing means 150 representing accelerator depression elimination data to provide information as to the position at which vehicle the elimination of accelerator depression is to occur in order to achieve a determined lower velocity at a desired position by means of the engine brake of the vehicle.

The electronic control unit 100 is signal-connected to said free running activation informing means 155 via a link 55. The electronic control unit 100 is arranged via the link 55 so as to send a signal to said free running activation informing means 155 representing free running activation data in order to provide information as to the position at which the activation of free running of the vehicle, i.e. shifting the gears into neutral, is to occur in order to achieve a determined lower velocity at a desired position by means of free running.

The electronic control unit is arranged so as to process said velocity change data for the velocity change needed to achieve a determined lower velocity at a desired position and said condition data regarding the forward travel of the vehicle in order to determine the retardation of the vehicle under the action of the engine brake of the vehicle or free running of the vehicle, in order to thereby decide the position of the vehicle at which the elimination of accelerator depression or activation of free running is to occur. The electronic control unit is here arranged so as to send accelerator depression elimination data to said accelerator depression elimination informing means 150 or free running activation data to said free running activation means 155.

The electronic control unit is arranged so as to process said object data from the camera element 1 12 comprising data regarding speed limits from speed limit signs in connection with said braking process and/or said cartographic data from the cartographic information unit 1 14a of the route determining means 1 14 comprising speed limits, topology and any curves in order to determine the position of an upcoming speed limit.

The electronic control unit is arranged so as to process said distance data from the distance determining means in order to determine the distance to a preceding vehicle in order to achieve a determined lower velocity at a desired position relative to the preceding vehicle.

According to one variant, the electronic control unit 100 is arranged so as to process velocity data and, in applicable cases, said communication data, accelerator depression data, braking data, engine rpm data, transmission data, precipitation data, rolling resistance data and/or air resistance data in order to determine the retardation of the vehicle under the action of said engine brake; and to decide, based on said determination, the position of the vehicle at which said elimination of accelerator depression or activation of free running is to occur.

The system I further comprises learning means 160 for learning in order to improve the determination of the position at which said elimination of accelerator depression or activation of free running is to occur in order for the retardation of the vehicle by means of engine braking or free running to a desired velocity to occur at a position that is the desired position.

The electronic control unit 100 is signal-connected to said learning means 160 via a link 60a. The electronic control unit 100 is arranged via the link 60a so as to send a signal to said learning means 160 representing position data for the actual position at which the desired lower velocity was achieved by means of the elimination of accelerator depression or activation of free running at a determined position by means of utilizing the engine brake of the vehicle or by means of free running under the conditions prevailing during the relevant instance. The electronic control unit 100 is signal-connected to said learning means 160 via a link 60b. The electronic control unit 100 is arranged via the link 60b so as to receive a signal from said learning means 160 representing correction data for correcting so that, in a subsequent instance, the elimination of accelerator depression or activation of free running will occur at a position in connection with which said correction data are processed.

According to one variant, said learning means constitute an integral part of the electronic control unit 100. According to one variant, said learning means 160 comprise a local neural network.

Fig. 3 schematically illustrates a block diagram of a method for velocity adaptation during the forward travel of a motor vehicle according to one embodiment of the present invention.

According to one embodiment, the method for velocity adaptation during the forward travel of a motor vehicle comprises a first step S1 . In this step, the retardation of the vehicle under the action of the engine brake or free running of the vehicle is determined based on current conditions.

According to one embodiment, the method for velocity adaptation during the forward travel of a motor vehicle comprises a second step S2. In this step, the position of the vehicle at which the elimination of accelerator depression in order to retard the vehicle by means of the engine brake of the vehicle or the activation of free running in order to retard the vehicle is to occur in order to achieve a determined lower velocity at a desired position is decided based on said determination, A diagram of an embodiment of a device 500 is shown with reference to Fig. 4. In one embodiment, the control unit 100 described with reference to Fig. 2 can 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 520 has a first memory section 530 in which a computer program, such as an operating system, is stored in order to control the function of the device 500. The device 500 further comprises a bus controller, a serial communication port, I/O elements, an A/D converter, a time and date input and transfer unit, an event counter and an interrupt controller (not shown). The non-volatile memory 520 also has a second memory section 540.

A computer program P is provided that contains routines for velocity adaptation during the forward travel of a motor vehicle according to the innovative method. The program P comprises routines for determining, based on current conditions regarding the forward travel of the vehicle, the retardation of the vehicle under the action of the engine brake or free running of the vehicle. The program P contains routines for deciding, based on said determination, the position of the vehicle at which the elimination of accelerator depression to retard the vehicle or the activation of free running to retard the vehicle is to occur in order to achieve a determined lower velocity at a desired position. The program P can be stored in an executable form or in a compressed form in a memory 560 and/or in a read/write memory 550.

When it is stated that the data processing unit 510 performs a given function, it is to be understood that the data processing unit 510 executes a certain part of the program that is stored in the memory 560, or a given part of the program that is 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 to communicate with the data processing unit 510 via a data bus 512. The separate memory 560 is intended to communicate with the data processing unit 510 via a data bus 51 1 . The read/write memory 550 is arranged so as to communicate with the data processing unit 510 via a data bus 514. For example, links connected to the control unit 100 can be connected to the data port 599. When data are received at the data port 599, they are stored temporarily in the second memory section 540. Once received input data have been stored temporarily, the data processing unit 510 is arranged so as to execute code in a manner a described above. The signals received at the data port 599 can be used by the device 500 in order to determine, based on current conditions regarding the forward travel of the vehicle, the retardation of the vehicle under the action of the engine brake or free running of the vehicle. The signals received at the data port 599 can be used by the device 500 in order to decide, based on said determination, the position of the vehicle at which the elimination of accelerator depression to retard the vehicle by means of the engine brake of the vehicle or the activation of free running to retard the vehicle is to occur in order to achieve a determined lower velocity at a desired position.

Parts of the methods described herein can be performed by the device 500 with the help of the data processing unit 51 0 that runs the program stored in the memory 560 or the read/write memory 550. The method described herein is executed when the device 500 runs the program.

The foregoing description of the preferred embodiments of the present invention has been provided for purposes of illustration and description. It is not intended to be exhaustive, or to limit the invention to the variants described. Many modifications and variations will obviously be apparent to one skilled in the art. The embodiments have been chosen and described in order to best clarify the principles of the invention and its practical applications, and to thereby enable one skilled in the art to understand the invention with regard to various embodiments and with the various modifications that are applicable for the intended use.

Claims

1. A method for velocity adaptation during the forward travel of a motor vehicle, comprising the step of retarding the vehicle by means of the engine brake of the vehicle by eliminating accelerator depression or by means of free running to achieve a determined lower velocity at a desired position, characterized by the steps of: determining (S1 ), based on current conditions regarding the forward travel of the vehicle, the retardation of the vehicle under the action of said engine brake or free running; and deciding (S2), based on said determination, a position of the vehicle at which said elimination of accelerator depression or activation of free running activation is to occur.

2. A method according to claim 1 , wherein said current conditions comprise the velocity of the vehicle.

3. A method according to claim 1 or 2, wherein said current conditions comprise at least one of the following parameters: vehicle mass, the gear that the vehicle transmission is in, topography along the route of the vehicle, engine rpm, air resistance, rolling resistance and wirelessly communicated outside information.

4. A method according to any of claims 1 -3, wherein said desired position refers to the vehicle route and pertains, for example, to a lower speed limit, curves or the presence of speed cameras.

5. A method according to claim 4, comprising the step of determining said desired position based on cartographic data and/or sensing by means of camera elements (1 12).

6. A method according to any of claims 1 -3, wherein said desired position refers to a desired distance to a preceding vehicle.

7. A method according to any of claims 1 -6, comprising the step of determining said position based on distance determining elements (1 16), such as radar elements or laser elements.

8. A system (I) for velocity adaptation during the forward travel of a motor vehicle, comprising means for retarding the vehicle by means of the engine brake of the vehicle by eliminating accelerator depression or by means of free running to achieve a determined lower velocity at a desired position, characterized by means (100, 120) for determining, based on current conditions regarding the forward travel of the vehicle, the retardation of the vehicle under the action of said engine brake or free running; and means (100, 1 10) for deciding, based on said determination, a position of the vehicle at which said elimination of accelerator depression or activation of free running is to occur.

9. A system according to claim 8, wherein said current conditions comprise the vehicle velocity.

10. A system according to claim 8 or 9, wherein said current conditions comprise at least one of the following parameters: vehicle mass, the gear that the vehicle transmission is in, topography along the route of the vehicle, engine rpm, air resistance, rolling resistance and wirelessly communicated outside information.

11. A system according to any of claims 8-10, wherein said desired position refers to the vehicle route and pertains, for example, to a lower speed limit, curves or the presence of speed cameras.

12. A system according to claim 1 1 , comprising means (1 12, 1 14) for determining said desired position based on cartographic data and/or sensing by means of camera elements.

13. A system according to any of claims 8-12, wherein said desired position refers to a desired distance to a preceding vehicle.

14. A system according to any of claims 8-13, comprising means (1 16) for determining said position based on distance determining elements, for example radar elements or laser elements.

15. A motor vehicle (1 ) containing a system (I) according to any of claims 8- 14.

16. A computer program (P) for velocity adaptation during the forward travel of a motor vehicle, wherein said computer program (P) contains program code that, when it is run by an electronic control unit (100) or a second computer (500) connected to the electronic control unit (100), enables the electronic control unit (100) to perform the steps according to 1 -7.

17. A computer program product comprising a digital storage medium that stores the computer program (P) according to claim 16.