EP3145777A1

EP3145777A1 - Method and system for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel

Info

Publication number: EP3145777A1
Application number: EP15795544.4A
Authority: EP
Inventors: Jonny Andersson; Linus Bredberg
Original assignee: Scania CV AB
Current assignee: Scania CV AB
Priority date: 2014-05-21
Filing date: 2015-05-20
Publication date: 2017-03-29
Also published as: SE1450604A1; BR112016024853A2; WO2015178838A1; EP3145777A4; KR20170007362A

Abstract

The present invention concerns a method for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel, wherein retardation of the vehicle by means of engine braking and/or coasting of the vehicle is taken into account. The method comprises the step of: continuously determining (S1 ) a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle, wherein the step of continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle comprises the step of continuously determining driving resistance along the route of travel of the vehicle during engine braking and/or coasting. The method further comprises the step of selecting the time for initiating retardation by means of engine braking and/or coasting of the vehicle in the event that the velocity profile resulting from engine braking and/or coasting is found to contain a target velocity in said comparison. The present invention also concerns a system method for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel. The present invention also concerns a motor vehicle. The present invention also concerns a computer program and a computer program product.

Description

Method and system for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel

5 TECHNICAL FIELD OF THE INVENTION

The invention concerns a method for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel according to the preamble to claim 1 . The invention concerns a system for improving the operating efficiency of a vehicle during driving of a vehicle along a route of0 travel. The invention also concerns a motor vehicle. The invention also concerns a computer program and a computer program product.

BACKGROUND

Cruise controls and similar driver aids are becoming more and more5 intelligent. Today there is a plurality of systems on the market that make use of cartographic data to drive the vehicle in a fuel-efficient manner. These systems are, however, adapted so as to take into account only the appearance of the topography, which, in practice, makes them functions that are suitable for use on motorways and corresponding roads. 0 Current systems are based entirely on a preset setpoint velocity. The topology-based cruise controls are allowed to deviate from same by only a certain percentage or km/h. If the vehicle in question drives onto a smaller road with curves and velocity limitations, it is appropriate to turn off the cruise control, as the driver himself will need to brake in advance of any curve. On5 smaller roads with many curves it is also difficult for a driver to drive optimally from the standpoint of fuel economy. This is because it is often difficult to see what is happening around the next curve. EP2476597 describes a method for retarding a vehicle, for example by means of engine braking, in order not to exceed upcoming velocity limitations.

EP1923291 A2 describes a method for improving the efficiency of a vehicle by using engine braking/coasting in advance of an upcoming velocity limitation, wherein a coasting velocity is determined and compared to target velocities associated with an upcoming section of road, and wherein the initiation of coasting is determined based on said comparison.

OBJECT OF THE INVENTION

One object of the present invention is to provide a method and a system for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel that enables safe and fuel-efficient driving of the vehicle in connection with velocity-limiting factors.

SUMMARY OF THE INVENTION

These and other objects, which are presented in the description below, are achieved by means of a method, a system, 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 the accompanying independent claims. Preferred embodiments of the method and the system are defined in the accompanying non-independent claims.

According to the invention, the objects are achieved by means of a method for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel, wherein retarding of the vehicle via engine braking and/or coasting of the vehicle is taken into account, and comprising the step of: continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with the velocity-limiting factors occurring along the route of travel of the vehicle. The step of continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle comprises the step of continuously determining the driving resistance along the route of travel of the vehicle during engine braking and/or coasting. The method further comprises the step of selecting the time for initiating retardation by means of engine braking and/or coasting of the vehicle in the event that the velocity profile resulting from engine braking and/or coasting is determined to contain a target velocity in said comparison. Safe and fuel-efficient driving of the vehicle in connection with velocity-limiting factors is enabled hereby.

The time/distance before action must be taken to initiate engine braking and/or coasting in order to achieve a target velocity associated with velocity- limiting factors such as curvature or a change in velocity limitation is adapted appropriately. A trade-off between performance and fuel economy is enabled hereby. According to one embodiment, the time for initiating retardation is selected as essentially zero, i.e. in the event that the velocity profile resulting from engine braking and/or coasting of the vehicle is determined to contain a target velocity, retardation is initiated by means of engine braking and/or coasting of the vehicle. Fuel-efficient driving of the is achieved by thus initiating the engine braking and/or coasting so that a target velocity associated with velocity-limiting factors such as curvature or a change in the velocity limitations can be achieved. Selecting a time other than one in immediate proximity to the determination that the velocity profile includes the target velocity thus makes it possible to limit the distance- and/or the time prior to initiation in order to thus be able to take into account, for example, a very large velocity change, for example, from 80 to 30 km/h, whereupon the distance/time until when the velocity limit must be achieved can be shortened, which may entail that a degree of retardation via brake activation is required. Selecting a time other than one in immediate proximity to the determination that the velocity profile contains the target velocity makes it possible to take into account both fuel economy and efficient driving of the vehicle wherein, for example, different modes can be set for more or less fuel-efficient driving. Continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle by continuously determining the driving resistance along the route of travel of the vehicle during engine braking and/or coasting enables the determination of a more accurate velocity profile resulting from engine braking and/or coasting. More fuel-efficient driving of the vehicle is thereby enabled wherein, for example, the topology of the roadway is taken into account. The step of continuously determining the driving resistance along the route of travel of the vehicle during engine braking and/or coasting suitably comprises a determination of the grade resistance, friction characteristics of the vehicle drive train, air resistance and/or rolling resistance.

The target velocities are suitably determined based on the velocity-limiting factors occurring along the route of travel of the vehicle.

According to one embodiment of the method, said velocity-limiting factors include the curvature of the route of travel, whereupon a target velocity is determined based on the maximum permissible lateral acceleration of the vehicle. Safe driving of the vehicle is enabled hereby, in that the velocity is adapted when taking curves.

According to one embodiment of the method, said velocity-limiting factors include velocity limitation corresponding to a target velocity along the route of travel of the vehicle. The target velocity is thus determined based on the velocity limitation. It is thus ensured that adaptation to velocity limitations along the route of travel of the vehicle will take place in a safe and fuel- efficient manner. According to one embodiment of the method, the step of continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities occurs based on a predetermined distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle of the vehicle. This makes it possible to adapt the retardation in the form of and/or coasting taking into account performance and fuel economy in dependence upon how long prior to the velocity-limiting factor the engine braking and/or coasting of the vehicle is initiated, i.e. in dependence upon a distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle.

The embodiments of the system exhibit advantages corresponding to those of the corresponding embodiments of the method cited above.

FIGURE DESCRIPTION The present invention will be better understood with reference to the following detailed description read in conjunction with the accompanying drawings, wherein the same reference designations refer to the same parts consistently in the many 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 improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel according to one embodiment of the present invention;

Fig. 3a schematically illustrates a curvature profile; Fig. 3b schematically illustrates velocity profiles in dependence upon the curvature profile in Fig. 3a; Fig. 4 schematically illustrates a block diagram of a method for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel according to one embodiment of the present invention; and

Fig. 5 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 "continuously determine" refers herein, for example in connection with "continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle," to non-incremental determination or incremental determination, i.e. where the determination occurs with a given repeated frequency that can be regular, and that can be time-based or distance-based.

The term "velocity-limiting factors" refers herein to any arbitrary factors along the route of travel of the vehicle that entail that a velocity limitation of the vehicle is called for. "Velocity-limiting factors" include the curvature along the route of travel of the vehicle. "Velocity-limiting factors" include the speed limit along the route of travel of the vehicle. "Velocity-limiting factors" could also include other factors such as a narrowing road, road work along the route of travel of the vehicle, obstacles such as speed bumps along the route of travel of the vehicle, a degraded road surface, increased traffic density/risk of congestion etc. The term" engine braking of the vehicle" refers herein to driving of the vehicle wherein the vehicle wheels rev the vehicle engine without any fuel being injected into the engine. The term "engine braking of the vehicle" can here occur during a gear-shifting process, wherein a gear shift may, for example, be necessary during engine braking from a higher velocity, e.g. 70 km/h, to a significantly lower velocity, e.g. 30 km/h. Higher friction losses are attained in lower gears, i.e. the lower the gear, the greater the retardation. The term "engine braking of the vehicle" consequently comprises driving of the vehicle wherein the vehicle wheels rev the vehicle engine without any fuel being injected into the engine, but wherein a gear-shifting process can occur.

The term "coasting" refers herein to driving of the vehicle wherein the vehicle drive train is disengaged in such a way that the vehicle wheels do not rev the vehicle engine, for example, by shifting gears into neutral and/or disengaging them. 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 arbitrary suitable vehicle, such as a bus or car. The vehicle contains a system I according to the present invention. Fig. 2 schematically illustrates a block diagram of a system I for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel according to one embodiment of the present invention.

The system I comprises an electronic control unit 100.

The system I comprises means 1 10 for determining the occurrence of velocity-limiting factors along the route of travel of the vehicle. According to one variant, the means for determining occurring velocity-limiting factors are arranged for continuous determination. The means 1 10 for determining occurring velocity-limiting factors are arranged so as to determine target velocities based on the velocity-limiting factors.

Said velocity-limiting factors include the curvature of the route of travel. Said velocity-limiting factors include changes in velocity limitation along the route of travel of the vehicle.

According to one variant, the means 1 10 for continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle comprise a cartographic information unit 1 12 containing cartographic data comprising characteristics of the roadway along the route of travel of the vehicle comprising velocity-limiting factors in the form of the curvature of and changes in velocity limitation along the route of travel of the vehicle.

According to one variant, the means 1 10 for continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle comprise means 1 14 for determining the vehicle position. The means 1 14 for determining the vehicle position comprise a geographic positioning system for continuously determining the vehicle position along the route of travel. An example of a geographic positioning system can be GPS.

According to one variant, the cartographic information unit 1 1 2 and the means 1 14 for determining the vehicle position comprise means 1 10a for determining the route of travel of the vehicle, wherein the means for determining the route of travel of the vehicle are arranged so as to provide predetermined characteristics of the roadway along the route of travel of the vehicle comprising velocity-limiting factors in the form of the curvature of and changes in velocity limitation along the route of travel of the vehicle. Said cartographic data in the cartographic information unit 1 12 also include characteristics of the roadway along the route of travel of the vehicle comprising its topography. The cartographic information unit 1 12 and the means 1 14 for determining the vehicle position consequently make it possible to continuously identify the vehicle position and characteristics of the roadway comprising velocity- limiting factors in the form of the curvature of and changes in velocity limitation along the route of travel of the vehicle.

The cartographic information unit 1 12 makes it possible to determine, in advance, velocity-limiting factors such as the curvature of and changes in velocity limitation along the route of travel of the vehicle, and to thereby determine a velocity profile along the route of travel of the vehicle as well. According to one variant, the means 1 10 for continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle comprise a camera element 1 16. The camera element 1 1 6 is arranged so as to detect characteristics of the roadway comprising velocity-limiting factors in the form of the curvature of and changes in velocity limitation along the route of travel of the vehicle. The camera element 1 1 6 is arranged so as to detect the conformation of the widening of the road comprising bends in the roadway and/or road markings in order to thereby determine bends in the roadway along which the vehicle is traveling. The camera element 1 16 is arranged so as to detect road signs along the route of travel of the vehicle comprising speed limit signs, wherein the camera element 1 16 is arranged so as to determine changes in velocity limitation along the route of travel of the vehicle by sensing speed limit signs. The camera element can comprise one or more cameras for such detection.

According to one variant, the means 1 10 for determining the occurrence of velocity-limiting factors along the route of travel of the vehicle comprise communication means for communication between the vehicle and other vehicles or the vehicle and other entities in order to communicate velocity- limiting factors such as the start of congestion or the like. The means 1 10 for continuously determining the occurrence of velocity- limiting factors along the route of travel of the vehicle include means for performing said determination based on a predetermined distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle. According to one embodiment, the means 1 10 for continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle comprise means for performing said determination based on a predetermined distance horizon ahead of the vehicle along the route of travel of the vehicle, wherein said distance horizon constitutes a suitable window in the form of a distance from the current vehicle position and forward along the route of travel of the vehicle. According to one embodiment, the magnitude of the distance horizon is on the order of several hundred meters, e.g. roughly 500 meters. The distance horizon can consist of any arbitrary suitable distance. According to one variant, the distance horizon is dependent upon the vehicle velocity.

The determination of the maximum velocity comprising a target velocity and associated velocity profile based on the maximum permissible lateral acceleration for a velocity-limiting factor in the form of curvature utilizes information about the curvature of the roadway along the route of travel of the vehicle, wherein the following equation A) is utilized: where v_max(s) is the maximum velocity on the stretch s ahead of the vehicle, 3iat,max(s) is the maximum permissible lateral acceleration on the stretch s ahead of the vehicle, and c(s) is the curvature of the stretch s ahead of the vehicle.

The system I comprises means 120 for continuously determining the vehicle velocity. According to one variant, the means 1 20 for continuously determining the vehicle velocity comprise velocity-measuring elements. The system I comprises means 130 for determining the maximum permissible lateral acceleration. The means 130 for determining the maximum permissible lateral acceleration comprise the determination of a predetermined maximum permissible lateral acceleration, which is based on normal conditions with regard to vehicle characteristics, such as the length of the vehicle, width of the vehicle, carriage of the vehicle, load distribution of the vehicle, weight distribution of the vehicle, axle pressure of the vehicle and/or environmental characteristics such as the effective lane width, friction characteristics of the roadway, visibility conditions and the slope characteristics of the roadway. According to one embodiment, the predetermined maximum permissible lateral acceleration is on the order of 2 m/s². The maximum permissible lateral acceleration here consists of a predetermined maximum permissible lateral acceleration. According to one alternative, or complementary, variant the electronic control unit 100 contains stored data concerning the maximum permissible lateral acceleration.

The system comprises means 100 for determining a target velocity based on the maximum permissible lateral acceleration. According to one variant, the means 100 for determining a target velocity based on the maximum permissible lateral acceleration comprise the electronic control unit 100. According to one variant (not shown), the means 1 00 for determining a target velocity based on the maximum permissible lateral acceleration comprise a unit that is in signal communication with the electronic control unit 1 00.

The system I comprises means 140 for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle.

The means 140 for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities comprise means for performing said determination based on a predetermined distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle. The distance horizon constitutes a suitable window in the form of a distance from the current vehicle position and forward along the route of travel of the vehicle. According to one embodiment, the magnitude of the distance horizon is on the order of several kilometers. The distance horizon can consist of any arbitrary suitable distance. According to one variant, the distance horizon is dependent upon the vehicle velocity.

The means 140 for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle comprise means 142 for continuously determining driving resistance along the route of travel of the vehicle during engine braking and/or coasting.

The means 142 for continuously determining driving resistance along the route of travel of the vehicle during engine braking and/or coasting comprise appropriate means 142a for determining grade resistance. The means 142a for determining grade resistance comprise or are contained in means for determining the topology along the route of travel of the vehicle, i.e. any grade of the roadway along the route of travel of the vehicle. According to one variant, the means 142a for determining grade resistance comprise a cartographic information unit containing cartographic data comprising characteristics of the roadway along the route of travel of the vehicle including the topology along the route of travel of the vehicle, and means for determining the vehicle position which, according to one variant, comprise a geographic positioning system, such as GPS, for continuously determining the vehicle position along the route of travel. According to one variant, the cartographic information unit and the means for determining the vehicle position consist of the cartographic information unit 1 12 and the means 1 14 for determining the vehicle position. The means 142 for continuously determining driving resistance along the route of travel of the vehicle comprise suitable means 142b for determining friction characteristics of the vehicle drive train. The means 142b for determining friction characteristics of the vehicle drive train comprise means for determining speed differences between the wheels during driving/braking, so called "slip". Slip is determined by determining speed differences between the wheels. For instance, in that sensor elements measure the rotational speed of the wheels.

The means 142 for continuously determining driving resistance along the route of travel of the vehicle during engine braking and/or coasting suitably comprise means 142c for determining air resistance. The means 142c for determining air resistance comprise modeling means for estimating air resistance by means of an air resistance coefficient and vehicle characteristics comprising its frontal area and the square of the vehicle velocity. According to one variant, the means 142c for determining air resistance comprise a sensor element for measuring the air striking the vehicle, taking into account the vehicle geometry, including air deflectors for reducing air resistance.

The means 142 for continuously determining driving resistance along the route of travel of the vehicle during engine braking and/or coasting suitably comprise means 142d for measuring rolling resistance. The means 142d for determining rolling resistance comprise modeling means for estimating rolling resistance based on vehicle characteristics comprising the number of axles on the vehicle, the vehicle weight, the road surface and, in applicable cases, the tire type.

The means 142 for determining driving resistance F_res comprise calculating means (not shown in figure). According to one variant, the calculating means are arranged so as to continuously determine the acceleration/retardation, a_res that the driving resistance is generating, where F_res is the current driving resistance and m the vehicle mass. This occurs according to: The system I comprises means 100 for comparing determined velocity profiles for the vehicle velocity resulting from engine braking and/or coasting of the vehicle to target velocities associated with the velocity-determining factors occurring along the route of travel of the vehicle. According to one variant, the means 100 for said comparison consist of the electronic control unit 100. According to an alternative, or complementary variant (not shown), the means for said comparison consist of a separate unit that is in signal communication with the electronic control unit 100. The system comprises means 100, 150 for selecting the time for initiating retardation by means of engine braking and/or coasting of the vehicle in the event that the velocity profile resulting from engine braking and/or coasting of the vehicle is found to contain a target velocity in said comparison.

The means 100, 150 for selecting the time for initiating retardation by means of engine braking and/or coasting of the vehicle comprise means 150 for initiating retardation by means of engine braking and/or coasting of the vehicle. The means 150 for initiating retardation by means of engine braking and/or coasting of the vehicle comprise means for throttling the fuel injection/gas supply to the engine. The means for initiating retardation by means of engine braking and/or coasting of the vehicle comprise means for disengaging the vehicle drive train so that the vehicle wheels do not rev the engine comprising means for shifting the vehicle drive train into neutral and/or means for disengaging the clutch of the vehicle drive train.

According to one variant, the means 100, 150 for selecting the time for initiating retardation by means of engine braking and/or coasting of the vehicle comprise the electronic control unit 1 00, which is arranged herein so as to determine whether any delay of said initiation is justified. Consequently, the time for initiating retardation is normally set at essentially zero. Initiating engine braking and/or coasting so that a target velocity associated with a velocity-limiting factor such as curvature or a change in velocity limitation can be achieved by engine braking and/or coasting makes it possible to achieve fuel-efficient driving of the vehicle.

Determining/selecting a time other than one in immediate proximity to the determination of whether the velocity profile includes the target velocity thus makes it possible to limit the distance- and/or time before initiation so as to be able to take into account, for example, a very large velocity change, such as from 80 to 30 km/h, whereupon the distance/time until the velocity limitation must be achieved is shortened, which may entail that a degree of retardation by means of brake activation is required.

Selecting a time other than one in immediate proximity to the determination of whether the velocity profile includes the target velocity makes it possible to take into account both fuel economy and efficient driving of the vehicle wherein, for example, different modes can be set for more or less fuel- efficient travel. For example, the distance can be set at 600 meters in fuel- economy mode and 400 meters in a mode that is focused more on driving the vehicle efficiently. A situation could also arise in which it is necessary to apply the accelerator, e.g. because of an uphill stretch.

Such acceleration a in the form of retardation by means of braking or acceleration/reduction of retardation by applying the accelerator consequently contributes in such cases. The total necessary acceleration a_tof that is required will thus be:

< (s) = a +

The electronic control unit 100 is in signal communication with the means 1 10 for determining the occurrence of velocity-limiting factors along the route of travel of the vehicle via a link 10. The electronic control unit 100 is arranged so as to receive, via the link 10, a signal from the means 1 10 representing data for velocity-limiting factors such as curvature and/or changes in velocity limitation comprising velocity data for target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle.

The electronic control unit 100 is in signal communication with the means 1 10a comprising the cartographic information unit 1 12 and the means 1 14 for determining the vehicle position via a link 10a. The electronic control unit 1 00 is arranged so as to receive, via the link 10a, a signal from the means 1 10a representing cartographic data for velocity-limiting factors in the form of curvature and changes in velocity limitation comprising, according to one variant, a velocity profile with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle and position data for the position of the curvature relative to the vehicle.

The electronic control unit 100 is in signal communication with the camera element 1 16 via a link 16. The electronic control unit 100 is arranged so as to receive, via the link 16, a signal from the camera element 1 16 representing data for velocity-limiting factors comprising curvature data for the curvature of the roadway along the route of travel of the vehicle and data for changes in velocity limitation along the route of travel of the vehicle comprising velocity data for target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle.

The electronic control unit 100 is in signal communication with the means 120 for continuously determining the vehicle velocity via a link 20. The electronic control unit 100 is arranged so as to receive, via the link 20, a signal for continuously determining the vehicle velocity representing velocity data for the current vehicle velocity. The electronic control unit 100 is in signal communication with the means 130 for determining maximum permissible lateral acceleration via a link 30. The electronic control unit 1 00 is arranged so as to receive, via the link 30, a signal from the means 130 representing lateral acceleration data for the maximum permissible lateral acceleration.

The electronic control unit 100 is in signal communication with the means 140 for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle via a link 40a. The electronic control unit 100 is arranged so as to receive, via the link 40a, a signal from the means 140 representing retardation data resulting from engine braking and/or coasting of the vehicle.

The electronic control unit 100 is in signal communication with the means 142 for continuously determining driving resistance along the route of travel of the vehicle via a link 42. The electronic control unit 100 is arranged so as to receive, via the link 42, a signal from the means 142 representing driving resistance data.

The electronic control unit 100 is in signal communication with the means 142a for determining grade resistance via a link 42a. The electronic control unit 100 is arranged so as to receive, via the link 42a, a signal from the means 142a representing grade data for the grade of the roadway along the route of travel of the vehicle.

The electronic control unit 100 is in signal communication with the means 142b for determining friction characteristics of the vehicle drive train via a link 42b. The electronic control unit 100 is arranged so as to receive, via the link 42b, a signal from the means 142b representing friction data for friction characteristics of the vehicle drive train. The electronic control unit 100 is in signal communication with the means 142c for determining air resistance via a link 42c. The electronic control unit 100 is arranged so as to receive, via the link 42c, a signal from the means 142c representing air resistance data for the vehicle along the route of travel of the vehicle.

The electronic control unit 100 is in signal communication with the means 142d for determining rolling resistance via a link 42d. The electronic control unit 100 is arranged so as to receive, via the link 42d, a signal from the means 142d representing rolling resistance data for the vehicle along the roadway along the route of travel of the vehicle.

The electronic control unit 100 is in signal communication with the means 140 for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle via a link 40b. The electronic control unit 100 is arranged so as to send, via the link 40b, a signal to the means 140 representing velocity data for the current vehicle velocity and driving resistance data for the current driving resistance.

The electronic control unit 100 is in signal communication, via a link 50, with the means 150 for initiating retardation by means of engine braking and/or coasting of the vehicle in the event that the velocity profile resulting from engine braking and/or coasting is found to contain a target velocity in said comparison. The electronic control unit 100 is arranged so as to send, via the link 50, a signal to the means 150 initiation data for initiation comprising chronological data for the time of initiation, which time can be in immediate proximity to the determination, or delayed in order to limit the distance or time before an action in the form of said initiation can be performed.

The electronic control unit 100 is arranged so as to process said data for velocity-limiting factors and distance data in order to determine comprising velocity data for target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle.

The electronic control unit 100 is arranged so as to process said driving resistance data and velocity data and send said data to the means 140 for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle. The means 140 process said data in order to determine velocity profile data for the velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle.

The electronic control unit 100 is arranged so as to compare said velocity data for target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle with said velocity profile data for the velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle in order to determine comparison data. The electronic control unit 100 is arranged so as to determine initiation data for initiating engine braking and/or coasting of the vehicle comprising data for the time of initiation and so as to send said initiation data to the means 150 in the event that the comparison data contain data wherein the velocity profile resulting from engine braking and/or coasting and data for the target velocity are essentially in agreement.

The means 150 are arranged so as to initiate retardation by means of engine braking and/or coasting of the vehicle in the event that the velocity profile resulting from engine braking and/or coasting is found to contain a target velocity in said comparison.

Fig. 3a schematically illustrates a curvature profile R in the form of an S- curve with a first curvature having a radius of curvature r1 and a second curvature having a radius of curvature r2. Fig. 3b schematically illustrates velocity profiles for the curvature profile in Fig. 3a determined by means of the system I according to the present invention.

The dotted line in Fig. 3b shows a desired reference velocity for following the requested velocity profile. Retardation in requested here in the form of engine braking and/or coasting before the first curvature in order to retard the vehicle to a velocity adapted for the curve and corresponding to the permissible lateral acceleration. Alternatively, the request in the form of engine braking consists of a requested velocity, such as 1 0 km/h, to ensure that the lower limit is not reached before the curvature is reached due to, for example, an interposed uphill stretch. Alternatively, the request in the form of engine braking could comprise an acceleration request to the engine, or a signal concerning throttling of the fuel supply.

The broken lines in Fig. 3b show a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle that results in a velocity that is too low in relation to the target velocity adapted for the first curvature and corresponding to the permissible lateral acceleration, where achieving the correct velocity at the first curvature would entail having to apply the accelerator. The broken/dotted line in Fig. 3b shows a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle that entails a speed that is too high in relation to the target velocity adapted for the first curvature and corresponding to the permissible lateral acceleration, where additional braking would consequently be required in order to achieve the correct velocity at the first curvature.

The thick solid line in Fig. 3b shows a velocity profile based on the maximum permissible lateral acceleration.

The thinner of the two solid lines in Fig. 3b shows a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle that results in the correct velocity in relation to the target velocity that corresponds to the permissible lateral acceleration and has been adapted for the first curvature. The vehicle should thus, during engine braking and/or coasting of the vehicle, achieve a velocity corresponding to the velocity limit for the first curvature during the first curvature.

Fig. 4 schematically illustrates a block diagram of a method for improving the operating efficiency of a vehicle during driving of a vehicle along a route according to one embodiment of the present invention. Retardation of the vehicle by means of engine braking and/or coasting of the vehicle is thus taken into account.

According to one embodiment, the method for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel comprises a step S1 . In this step, a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle is continuously determined as the basis for a comparison with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle.

The step of continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle comprises the step S1 a of continuously determining driving resistance along the route of travel of the vehicle during engine braking and/or coasting.

According to one embodiment, the method for improving the operating efficiency of a vehicle driving along a route of travel comprises a step S2. In this step, a time for initiating retardation by means of engine braking and/or coasting of the vehicle is selected in the event that the velocity profile resulting from engine braking and/or coasting is found to contain a target velocity in said comparison.

According to one embodiment of the method, the step of continuously determining driving resistance along the route of travel of the vehicle during engine braking and/or coasting comprises the step of determining grade resistance, friction characteristics of the vehicle drive train, air resistance and/or rolling resistance.

According to one embodiment of the method, said velocity-limiting factors include the curvature of the route, whereupon a target velocity is prescribed based on the maximum permissible lateral acceleration of the vehicle.

According to one embodiment of the method, said velocity-limiting factors include changes in velocity limitation corresponding to a target velocity along the route of travel of the vehicle.

According to one embodiment of the method, the step of continuously determining a velocity profile the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocity occurs based on a predetermined distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle.

A diagram of an embodiment of a device 500 is shown with reference to Fig. 5. In one embodiment, the control unit 1 00 that is 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 part 530 in which a computer program, such as 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 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 part 540.

A computer program P is provided that contains routines for improving the operating efficiency of a vehicle during driving of the vehicle along a route of travel according to the innovative method. The program P contains routines for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle. The routines for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle comprise routines for continuously determining the driving resistance along the route of travel of the vehicle during engine braking and/or coasting. The program P contains routines for selecting a time for initiating retardation by means of engine braking and/or coasting of the vehicle in the event that the velocity profile resulting from engine braking and/or coasting includes a target velocity in said comparison. The program P can be stored in executable form or 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 certain 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 for communication with the data-processing unit 51 0 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, the links connected to the control unit 1 00 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 part 540. Once received input data have been temporarily stored, the data-processing unit 510 is arranged so as to carry out the execution of code in a manner as described above. The signals received at the data port 599 can be used by the device 500 for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle. The signals that are used by the device 500 for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle include use in continuously determining the driving resistance along the route of travel of the vehicle during engine braking and/or coasting. The signals received at the data port 599 can be used by the device 500 to select a time for initiating retardation by means of engine braking and/or coasting of the vehicle in the event that the velocity profile resulting from engine braking and/or coasting is found to contain a target velocity in said comparison.

Parts of the methods described herein can be performed by the device 500 with the help of the data-processing unit 510 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 illustrative and description purposes. It is not intended to be exhaustive, or to limit the invention to the described variants. 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 explain the invention and its practical applications, and to thereby enable one skilled in the art to understand the invention in its various embodiments and with the modifications that are appropriate for the intended use.

Claims

1 . A method for improving the operating efficiency of a vehicle (1 ) during driving of a vehicle along a route of travel, wherein retardation of the vehicle by means of engine braking and/or coasting of the vehicle is taken into account, and comprising the step of: continuously determining (S1 ) a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with velocity-limiting factors occurring along the route of travel of the vehicle, characterized in that the step of continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle comprises the step of continuously determining driving resistance along the route of travel of the vehicle during engine braking and/or coasting, and in that the method comprises the step of selecting the time for initiating retardation by means of engine braking and/or coasting of the engine in the event that the velocity profile resulting from engine braking and/or coasting is found to contain a target velocity in said comparison.

2. A method according to claim 1 , wherein the step of continuously determining the driving resistance along the route of travel of the vehicle during engine braking and/or coasting comprises determining grade resistance, friction characteristics of the vehicle drive train, air resistance and/or rolling resistance.

3. A method according to claim 1 or 2, wherein said velocity-limiting factors include the curvature of the route, wherein a target velocity is prescribed based on the maximum permissible lateral acceleration of the vehicle.

4. A method according to any of claims 1 -3, wherein said velocity-limiting factors include changes in velocity limitation corresponding to a target velocity along the route of travel of the vehicle.

5. A method according to any of claims 1 -4, wherein the step of continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities occurs on the basis of a predetermined distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle.

6. A system (I) for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel, wherein retardation of the vehicle by means of engine braking and/or coasting is taken into account, and comprising means (140) for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities associated with velocity- limiting factors occurring along the route of travel of the vehicle, characterized in that the means (140) for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle comprise means (142) for continuously determining driving resistance along the route of travel of the vehicle during engine braking and/or coasting, and in that the system (I) further comprises means (1 00, 150) for selecting the time for initiating retardation by means of engine braking and/or coasting of the vehicle in the event that the velocity profile resulting from engine braking and/or coasting of the vehicle is found to contain a target velocity in said comparison.

7. A system according to claim 6, wherein the means (140) for continuously determining driving resistance along the route of travel of the vehicle comprise means (142a) for determining grade resistance, means (142b) for determining friction characteristics of the vehicle drive train, means (142c) for determining air resistance and/or means (142d) for determining rolling resistance.

8. A system according to claim 6 or 7, wherein said velocity-limiting factors comprise the curvature of the route of travel, wherein means (100) are present for prescribing a target velocity based on the maximum permissible lateral acceleration of the vehicle.

9. A system according to any of claims 6-8, wherein said velocity-limiting factors include velocity limits corresponding to a target velocity along the route of travel of the vehicle.

10. A system according to any of claims 6-9, wherein the means (140) for continuously determining a velocity profile for the vehicle velocity resulting from engine braking and/or coasting of the vehicle as the basis for a comparison with target velocities comprise means for performing said determination on the basis of a distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle.

1 1 . A vehicle (1 ) comprising a system (I) according to any of claims 6-1 0.

12. A computer program (P) for improving the operating efficiency of a vehicle during driving of a vehicle along a route of travel, wherein said computer program (P) contains program code which, when run by an electronic control unit (1 00) or another computer (500) connected to the electronic control unit (100), enables the electronic control unit (100) to perform the steps according to claims 1 -5.

13. A computer program product comprising a digital storage medium that stores the computer program according to claim 12.