DE102016200717A1 - Method and device for carrying out a coasting function in a motor vehicle - Google Patents

Abstract

The invention relates to a method for operating a motor vehicle (1) with a coasting / sailing function, wherein the coasting / sailing function provides for opening a drive train (8) from a decoupling point (AP) to a coasting target point (AZ), comprising the following steps: - determining (S3) a particularly next preceding coasting target point (AZ) based on a most likely traveled route and a geographical position of the motor vehicle (1); Receiving (S4) from at least one route parameter for the preceding coasting destination point (ZP) from outside; Determining (S6) an outcoupling point (AP) for the preceding coasting target point (ZP) using the coasting / sailing function based on the at least one route parameter.

Description

Technical area

The invention relates to motor vehicles, in particular motor vehicles with a coasting function or sailing function.

Technical background

To reduce fuel consumption, sailing and Ausrollfunktionen can be provided in motor vehicles. The sailing function separates the engine from the drive train when the vehicle does not require a drive torque for a particular section of road ahead, and provides that the motor vehicle during driving of the section only without drive rolls or sails. The rolling can take place with the internal combustion engine switched on or off. After disconnecting the internal combustion engine from the drive train at a disengaging point, the rolling motor vehicle passes at an end speed the target point lying on the route. The kinetic energy of the vehicle in the target point and thus its speed depends on the kinetic energy in Auskuppelpunkt, occurring on the intermediate route energy losses, eg. B. energy losses due to air / rolling friction, and to be overcome or released potential energy. Conversely, when the target point speed is specified, the kinetic and potential energy required in the disengaging point can be determined and thus the optimum disengaging point can be calculated on the basis of the height profile and the vehicle speed. A distance of Auskuppelpunkts of the Ausrollpunktpunkt is determined by the kinetic energy of the motor vehicle and by the energy losses when driving on the route to the Ausrollzielpunkt due to air / rolling friction, and to be overcome or released potential energy.

A decision as to whether a change to a coasting or sailing operation should be carried out and at which distance the decoupling point lies before the target point should take into account all influences on the coasting behavior. The influences may include a gradient or height profile of the route, the vehicle mass and the air / rolling resistance. In general, the execution of the sailing function or coasting function can be determined by further vehicle parameters and route parameters, which can be variable. For example, the actual air resistance of the motor vehicle depends on the current wind situation. Furthermore, the rolling resistance may deviate from a predetermined value due to tire pressure deviations and / or road conditions.

Disclosure of the invention

According to the invention, a method for operating a motor vehicle with a coasting / sailing function according to claim 1 and a device and a motor vehicle according to the independent claims are provided.

Further embodiments are specified in the dependent claims.

• – Bestimmen eines insbesondere nächsten vorausliegenden Ausrollzielpunkts basierend auf einer am wahrscheinlichsten befahrenen Fahrstrecke und einer geografischen Position des Kraftfahrzeugs;
• – Empfangen von mindestens einem Streckenparameter für den vorausliegenden Ausrollzielpunkt von extern;
• – Ermitteln eines Auskoppelpunkts für den vorausliegenden Ausrollzielpunkt mithilfe der Ausroll-/Segelfunktion basierend auf dem mindestens einen Streckenparameter.

According to a first aspect, there is provided a method of operating a motor vehicle having a coasting / coasting function, wherein the coasting / coasting function provides for opening a driveline from a decoupling point to a coasting destination, comprising the steps of:

• Determining, in particular, a next preceding coasting destination based on a most likely traveled route and a geographical position of the motor vehicle;
• - receiving from outside at least one route parameter for the preceding coasting destination;
• Determining a decoupling point for the preceding coasting target point using the coasting / sailing function based on the at least one track parameter.

One idea of the above method is to externally z. B. for carrying out a coasting and sailing function on a section between a Auskuppelpunkt and a Ausrollpunktpunkt route parameters. B. from a central unit to receive.

The route parameters correspond to parameters which describe properties of the preceding route section by which a coasting process of the motor vehicle, in particular the speed at the coasting destination point, is influenced.

This makes it possible for imprecisely known or variable route parameters to be ascertained from fleet data, ie from a large number of motor vehicles that have traveled on the relevant road section. For this purpose, in the central unit movement data of motor vehicles, which have traveled the route section in a coasting / sailing mode, recorded, stored and used to determine the route parameters.

The at least one route parameter estimated in this way is made available to the motor vehicle before the section of track is approached before the next preceding coasting destination, so that the decoupling point can be determined therefrom as the vehicle position at which the coasting / sailing mode is started.

Furthermore, at least one vehicle parameter for the preceding coasting target point can be determined from a plurality of trips to the preceding coasting destination point when the coasting / sailing function is activated.

The vehicle parameters correspond to parameters of a specific motor vehicle, by which the coasting process of the motor vehicle is influenced, in particular the speed at the coasting target point is influenced.

In particular, by prior determination of the vehicle parameters based on the measured coasting events of a vehicle on different taxiing distances, its vehicle parameters can be determined more accurately and more quickly than would be possible without the route parameters.

With the aid of the route and vehicle parameters, it may further be decided whether a coasting and sailing function is performed to a preceding coasting target point and, if so, where the decoupling point should be, to achieve a predetermined target speed at a coasting destination by a coasting action , Due to the route parameters and vehicle parameters obtained, the decoupling point can be determined more accurately at a certain coasting target point, since the route parameters and thus the vehicle parameters can be specified by evaluating a large number of movement data of motor vehicles.

Previous methods for determining the vehicle parameters, eg. B. mass estimation method for determining a vehicle mass, based on the evaluation of own vehicle signals, taking into account constant, predetermined route parameters. On the other hand, it is now proposed to determine and take into account inaccurately known and varying road characteristics in order to obtain a more accurate estimate of the vehicle parameters and thus to allow a more accurate prediction of the coasting behavior, especially the speed in the coasting destination. The route parameters calculated from the coasting behavior of a plurality of motor vehicles to the specific coasting destination point in a central unit can be transmitted to the vehicle computer for calculating the coasting behavior. As a result, for example, inaccuracies of a height profile provided by map data, a deviating due to the nature of the road surface rolling resistance, z. B. due to a changed, aged or affected by weather conditions road surface, such. B. by snow, rain and the like, or deviations of the driving resistance due to back or headwind are taken into account. These influences can not be taken into account with the previous method for determining the Auskuppelpunkts.

As an alternative to an analytical calculation of the optimal decoupling point, the decoupling point can also be determined in a simplified manner based on optimum decoupling points stored in the central unit as a function of the vehicle parameters determined from coasting / sailing processes of motor vehicles with similar vehicle characteristics / parameters. As a result, the coasting behavior of the motor vehicle on the route section can be predicted more simply without complicated calculation or the route and vehicle parameters of the own motor vehicle can be verified. This allows z. Example, a faster and more accurate estimate of the vehicle mass and the driving resistances determined by the distances and vehicle parameters and a more accurate determination of an optimal Auskuppelpunkts to reach a certain Ausrollzielpunkt with a certain target speed.

Overall, vehicle parameters can be estimated faster and more accurately by the route parameters, which are provided in particular by externals and which take into account movement data of a large number of motor vehicles. By more accurately and better performing the coasting operation, it is possible to prevent coasting events at the coasting finish point from ending at a lower speed than planned. As a result, the acceptance of the coasting / sailing function can be significantly improved by drivers of motor vehicles.

It can be provided that, for determining the decoupling point, an equation of motion is evaluated based on an energy or power comparison between the sought decoupling point and the desired decoiling target point.

Furthermore, the at least one route parameter may indicate a parameter related to a link between a declutching point and the preceding coasting destination, in particular a height correction value for various possible disengaging points on the route for correcting a height profile before the coasting destination, a road-surface-dependent correction value of the rolling resistance coefficient for the route section is predetermined, a wind speed on the route section in the direction of travel of the motor vehicle and an air density of the ambient air along the route section.

Furthermore, after driving on a section of track with the coasting / sailing function activated, a coasting indication can be transmitted to the outside of the section of the route.

In particular, it can be provided that only coasting data are evaluated for those coasting events in which the speed at the coasting target point corresponds to a desired speed or deviates from it by no more than a predetermined tolerance amount.

• – eine Geschwindigkeit am Auskuppelpunkt;
• – eine Geschwindigkeit am Ausrollzielpunkt;
• – eine geografische Position des Auskuppelpunkts
• – eine geografische Position des Ausrollzielpunkts;
• – eine Länge der Ausrollstrecke;
• – eine Höhenänderung bzw. ein Höhenprofil über die Ausrollstrecke;
• – Strecken-, Geschwindigkeits- und/oder Beschleunigungsverläufe zwischen dem Auskuppelpunkt und dem Ausrollzielpunkt; und
• – als bekannt angenommene Fahrzeugparameter.

Furthermore, the at least one route parameter may be determined from one or more of the following coasting indications for one or more coasting events in a coasting destination:

• A speed at the disengaging point;
• A speed at the coasting destination;
• - a geographic position of the disconnection point
• A geographic position of the coasting target point;
• A length of the coasting distance;
• A height change or a height profile over the coasting distance;
• - Course, speed and / or acceleration curves between the Auskuppelpunkt and the Ausrollzielpunkt; and
• - Vehicle parameters assumed to be known.

It can be provided that at least one vehicle parameter is used for the calculation of the disengaging point for the preceding coasting target point, wherein the at least one vehicle parameter is determined from a plurality of trips with the coasting / sailing function activated to one or different coasting destinations.

der Räder umfasst, ein mit der effektiven Stirnfläche multiplizierte Luftwiderstandsbeiwert und/oder einen fahrzeugabhängigen Rollwiderstandskoeffizient umfasst.According to one embodiment, the at least one vehicle parameter may indicate a parameter related to the motor vehicle, and more particularly a vehicle mass, the generalized mass, the vehicle mass, and a rotational moment of inertia

of the wheels, comprises an air resistance coefficient multiplied by the effective end face and / or a vehicle-dependent rolling resistance coefficient.

• – eine Geschwindigkeit am Auskuppelpunkt;
• – eine Geschwindigkeit am Ausrollzielpunkt;
• – eine geografische Position des Auskuppelpunkts
• – eine geografische Position des Ausrollzielpunkts;
• – eine Länge der Ausrollstrecke;
• – eine Höhenänderung bzw. ein Höhenprofil über die Ausrollstrecke; und
• – Strecken-, Geschwindigkeits- und/oder Beschleunigungsverläufe zwischen dem Auskuppelpunkt und dem Ausrollzielpunkt;
• – als bekannt angenommene Streckenparameter.

Furthermore, the at least one vehicle parameter can be determined from one or more of the following coasting indications for one or more coasting events of the motor vehicle:

• A speed at the disengaging point;
• A speed at the coasting destination;
• - a geographic position of the disconnection point
• A geographic position of the coasting target point;
• A length of the coasting distance;
• A height change or a height profile over the coasting distance; and
• - Course, speed and / or acceleration curves between the Auskuppelpunkt and the Ausrollzielpunkt;
• - known as line parameters.

It can be provided that the determination of the at least one vehicle parameter in the motor vehicle or, after transmission of a coasting indication, information about the driving of the track section is carried out externally of the motor vehicle.

Furthermore, for the determination of the at least one vehicle parameter, only coasting operations can be used in sections whose route parameters are known with sufficient accuracy or have a high quality.

According to one embodiment, to determine the at least one vehicle parameter, only the coasting events can be evaluated in which the speed at the coasting target point corresponds to a desired speed or deviates from it by not more than a predetermined tolerance amount.

In particular, the estimated quality / accuracy of the estimation of the vehicle parameters and / or the route parameters can be evaluated. In particular, for the determination of the at least one vehicle parameter, only coasting operations can be used in sections whose route parameters are known with sufficient accuracy or have a high quality.

Furthermore, one or more of the coasting specifications for determining the at least one vehicle parameter and / or at least one route parameter for the route section can be transmitted externally, in particular to a central unit, and the determination of the at least one route parameter and / or of the at least one vehicle parameter carried out externally become. Alternatively, the determined at least one vehicle parameter can be determined in a control unit in the motor vehicle and transmitted to the outside, in particular to a central unit.

• – einen insbesondere nächsten vorausliegenden Ausrollzielpunkts basierend auf einer am wahrscheinlichsten befahrenen Fahrstrecke und einer geografischen Position des Kraftfahrzeugs zu ermitteln;
• – mindestens einen Streckenparameter für den vorausliegenden Ausrollzielpunkt von extern zu empfangen; und
• – einen Auskoppelpunkt für den vorausliegenden Ausrollzielpunkt mithilfe der Ausroll-/Segelfunktion basierend auf dem mindestens einen Streckenparameter zu ermitteln.

According to a further aspect, an apparatus for operating a motor vehicle having a coasting / sailing function is provided, wherein the coasting / sailing function provides for opening a drive train between a disengaging point and at least one coasting destination point. The device is designed to:

• To determine a particular next preceding coasting destination based on a most likely traveled route and a geographical position of the motor vehicle;
• To receive at least one route parameter for the preceding coast destination from externally; and
• To determine a decoupling point for the preceding coasting target point using the coasting / sailing function based on the at least one track parameter.

Brief description of the drawings

Embodiments are explained below with reference to the accompanying drawings. Show it:

1 a schematic representation of a motor vehicle and a central unit with which the motor vehicle communicates; and

2 a flowchart for illustrating a method for performing a rolling or sailing function in the motor vehicle.

Description of embodiments

1 shows a schematic representation of a motor vehicle 1 with a control unit 2 for performing a sailing and Ausrollfunktion. The car 1 comes with a drive system 6 driven in a conventional manner. The drive system 6 includes a drive unit 7 , a powertrain 8th and from the drive unit 7 powered wheels 9 , The drive unit 7 can drive a motor, such. B. include an internal combustion engine or a hybrid drive system with an internal combustion engine and an electric drive.

The powertrain 8th can in a conventional manner have a clutch and a transmission, via which the drive unit 7 can be coupled with the driven wheels. The drive system 6 can a clutch between the drive unit 7 and the driven wheels 9 produce or disconnect according to a control of the clutch.

The control unit 2 can with a driver assistance system 3 be connected to a navigation system 9 includes or is associated with such. The navigation system 9 allows z. B. using a GPS unit, a determination of a geographical position of the motor vehicle and provides access to map data available. Also, map data may otherwise be the control unit 2 be made accessible. The map data describe the course of sections of a route network including elevation and inclination information, z. B. in the form of a height profile.

Furthermore, the control unit is 2 with a communication device 4 connected via an appropriate communication channel with an external central unit 5 can communicate. The communication channel may be in the form of a known data communication channel, so that data between the communication device 4 and the central unit 5 can be exchanged in a conventional manner, for. B. packet bound.

The control unit 2 is designed to carry out a coasting function or sail function (coasting / sailing function). These provide, to save fuel the drive train by opening the clutch and so the drive unit 7 from the driven wheels 9 automatically decoupled. The disengaging takes place at a Auskuppelpunkt and the disengaged state is - if the coasting function or sailing function is not canceled - maintained at least until the motor vehicle 1 reached a Ausrollzielpunkt so that the motor vehicle 1 on a coasting / sailing section, ie a section of track between the Auskuppelpunkt and the Ausrollzielpunkt rolls or sails. A Ausrollzielpunkt is given by the fact that due to a traffic control (city entrance sign, speed limit, traffic lights and the like) at a certain location a certain speed of the motor vehicle is to be achieved, which is usually less than the current speed of the motor vehicle.

The decoupling shall occur at a disengaging time determined by means of the distance and vehicle parameters so that the speed of the motor vehicle at the reach target to be reached corresponds to a desired target speed.

In 2 is the method that is in the control unit based on the flowchart 2 is executed, described in more detail.

In step S1, a geographical vehicle position using the navigation system 9 certainly. Furthermore, from historical driving routes of the motor vehicle, by entering a destination search in the navigation system or by the limitations of the current route (no turning options), the most likely driving ahead route can be determined. The most likely traveled ahead route corresponds to an assumed route which the driver of the motor vehicle is most likely to drive. This route is used for further calculation.

Furthermore, in step S2, the map data in the navigation system 3 are accessed and extracted from the map data, a height profile for the most likely driving ahead route.

If the in-vehicle provided map data does not include a corresponding elevation profile, the elevation profile of the control unit may 2 also completely from the central unit 5 be provided to the most likely preceding route ahead.

Based on the geographical vehicle position, a preceding coasting target point is now determined in step S3. It will be checked in the following, whether a coasting should be started and at what place, d. H. Disengagement point, the coasting / sailing function should be activated.

Thus, for the next stretch of the most likely traveled route based on local traffic regulations, such. As speed limits, entry, priority rules, traffic situations such. B. a jam end, a construction site or the like, as well as on the height profile of the track section of one or more possible Ausrollzielpunkte for performing the coasting and sailing function are determined. These coasting targets provide vehicle positions of reduced or predetermined vehicle speed which can be approached without drive by means of the coasting and sailing functions.

Further, coasting targets for coasting or sailing operation may be provided directly from the central unit for the forward section of the most likely advanced route ahead 5 be taken from a database.

In step S4, communication is now established with the central processing unit 5 receive the current estimates of the line parameters for the particular roll out destination in the motor vehicle. Depending on whether the selection of the Ausrollpunktpunktes and the calculation of the Auskuppelpunktes in the control unit 2 of the motor vehicle 1 or in the central unit 5 should be done, the data in the control unit 2 or in the central unit 5 made available.

Further, in step S5, in the control unit 2 of the motor vehicle 1 Estimates for vehicle parameters provided. The vehicle parameters may include, for example, information on a vehicle weight, a rolling resistance value and an air resistance value. If there are no current estimated values of the parameters at the beginning, initial values z. From the vehicle type data.

The route parameters may include information about a height profile for the preceding route section to specify or compensate for inaccuracies of a height profile provided by map data, a different rolling resistance between the wheels and the road surface, e.g. B. due to a changed, aged or affected by weather conditions road surface, such. As by snow, rain and the like, and include deviations of the driving resistance due to back or headwind. Are these route parameters not from the central unit 5 or if there is an interruption in the communication due to a reception failure, the calculation of the decoupling point in the vehicle can also be carried out with a preset route parameter, such as a wind speed of 0 km / h.

Subsequently, one of the possible Ausrollzielpunkte can be selected on the forward section of the most likely traveled ahead driving route, the z. B. the longest Ausrollstrecke- / duration or the highest energy savings possible. If a minimally required coasting duration or distance or energy savings are not reached, the coasting process can be dispensed with. The selection can z. B. on the basis of simple criteria such as maximum height differences or also stored in the central database Ausrollergebnisse of vehicles with similar vehicle parameter values.

In step S6, the optimal decoupling point, e.g. In the form of a disengaging time or a disengaging waypoint for the selected coasting destination. The calculation may preferably be in the control unit 2 be made of the motor vehicle when the height profile of the route section lying ahead by map data in the motor vehicle 1 is present and the necessary route parameters from the central unit 5 were made available. If the calculation is alternatively in the central unit 5 made in the motor vehicle 1 present actual estimates of the vehicle parameters, including the desired coast down target point and, if appropriate, navigation information about the route ahead to the central processing unit 5 be transferred, or there already z. B. be present as a result of previous vehicle parameter estimates.

The calculation of the optimal decoupling point AP is based on the following energy / performance consideration of the coasting process.

The roll-out behavior of a vehicle can be described as a conversion of the energies between the decoupling point and the coasting target point. E _{kin + red_ZP} = E _{kin + red_AP} - ΔE _pot - W _AirR - W _RollR wherein E _{kin + rot_ZP of} the kinetic and rotational energy of the motor vehicle in Ausrollzielpunkt ZP, E _{kin + rot_AP} the kinetic and rotational energy of the motor vehicle in Auskuppelpunkt AP, ΔE _pot the potential energy difference between the Ausrollzielpunkt and the Auskuppelpunkt (E _ZP - E _AP ), W _LuftR the work to be performed between Auskuppelpunkt AP and target point ZP to overcome the air friction and W _RollR the work to be performed between Auskuppelpunkt AP and Ausrollpunktpunkt ZP to overcome the rolling friction.

Likewise, a description as integral from the disengagement time to the time of Zielpunkterreichung on the corresponding services is possible. The current partial services are included P _kin (t) + P _red (t) = P _Pot (t) _-PairR (t) _{-P RollR} (t) and, in that order, correspond to the kinetic power, the rotatory power, the potential power from the altitude change, the air friction power and the rolling friction power.

The coasting behavior of a motor vehicle depends very much on the terrain profile and its mass and the air and rolling resistance. At the beginning of coasting, kinetic and rotational energy is stored in the vehicle. During the coasting process, the change in kinetic and rotational energy results from the change in potential energy and the air and roll friction to be overcome.

To calculate the decoupling point, the currently available vehicle and route parameters are used. Inaccuracies are taken into account when establishing a robust target speed. If both the vehicle parameters and the route parameters are known with sufficient accuracy, the optimum disengagement point results.

• a) Kinetische und rotatorische Energie

When looking at the performance level, the following results for the individual terms:

• a) Kinetic and rotational energy

The rotational energy is divided into engine and wheel components. Typically, the gearbox is proportionally assigned to the engine and wheels. The rotational energy of the motor can be neglected for the rolling out, since the disengaged motor makes no amount to roll. The rotational energy of the wheels depends quadratically on the wheel speed, and this is proportional to the vehicle speed.

This makes it possible to _combine the vehicle mass m _Fzg and the rotational _{moment of inertia of} the wheels Θ into a generalized mass m _all for the calculation of the kinetic and rotational energy:

• b) Potentielle Energie

Thus results for the performance: P _{kin + red (t)} = m _all · ν (t) · α (t)

• b) Potential energy

The potential energy available or required during the coasting process depends on the height difference between disengaging point AP (height h _AP at the disengaging point) and destination point ZP (height h _ZP at the destination point) E _pot (t) = m _Fzg · g · (h _ZP - h _AP )

• c) Arbeit/Leistung zur Überwindung des Luftwiderstand

The current power from the altitude change results too P _pot (t) = m _Fzg · g · sin (α (t)) · ν (t) = m _Fzg · g · h (t) where α corresponds to a roadway inclination angle (pos., for slope) that can be calculated from the altitude change and h. (t) corresponds to the altitude change.

• c) work / performance to overcome air resistance

The power required to overcome the air friction is calculated from: p _airR (t) = c A / 2c _w ρ _air ( _Fzg (t) - ₀ ) ³ where c _w corresponds to an air resistance coefficient, A an effective frontal area, air of an air density, and ν ₀ a wind speed in the direction of travel.

• d) Arbeit/Leistung zur Überwindung des Rollwiderstand

Since the air friction depends on the current speed and the altitude profile, the total work to be done to overcome the air friction W _LuftR can only be calculated exactly as an integral over the current power:

• d) work / performance to overcome the rolling resistance

The power required to overcome the rolling friction is calculated from: P _RollR (t) = c _r · m _Fzg · g · cos (α (t)) · ν (t) = c _{r, Fzg} · C _{r, FB} · m _Fzg · g · cos (α (t)) · ν (t) wherein C _r : a rolling resistance coefficient, c _{r, Fzg} a vehicle- _dependent portion of the rolling resistance coefficient and c _{r, FB} a road-dependent correction _{value of} the rolling resistance coefficient, so that both the influence of the tires and the influence of the road surface and condition can be considered.

The integral from the decoupling point to the coasting target point via cos (α (t) * ν (t)) corresponds to the distance s _0.2D projected into the xy plane, which can be simply calculated from the navigation data. The work W _RollR necessary to overcome the rolling friction thus results from the distance projected into the plane between the decoupling point and the coasting target point ZP s _0.2D , irrespective of the time required for this

In order to calculate an optimal disengaging time at a given vehicle speed at the coasting target point from the above energy / performance consideration, one can describe the system behavior as a differential equation system.

From the above equations results for the acceleration

ergibt sich ein Differentialgleichungssystem, mit dem ausgehend vom Zeitpunkt im Ausrollzielpunkt t_ZP = 0, der Wegstrecke im Zielpunkt s_ZP = s(0) = 0, der gewünschten Geschwindigkeit im Zielpunkt ν_ZP = ν(0) und den bekannten Fahrzeug- und Streckenparametern inkl. des korrigierten Höhenprofils zeitlich rückwärts der Geschwindigkeits- und Streckenverlauf im ausgekuppelten Zustand ermittelt werden kann.And with

results in a differential equation system, starting from the time in the Ausrollzielpunkt t _ZP = 0, the distance at the destination s _ZP = s (0) = 0, the desired speed at the target point ν _ZP = ν (0) and the known vehicle and road parameters incl. the corrected height profile backwards in time the speed and distance course can be determined in the disengaged state.

ersetzt werden. Aus dem mit den Navigationsdaten gespeicherten Höhenprofil bzw. dem korrigierten Höhenprofil kann zu jedem Streckenpunkt die Höhe h(s) entnommen und die Steigung dh(s)/ds und somit h(t)/(t) ermittelt werden.Here, h (t) / v (t) is passed through

be replaced. From the altitude profile or the corrected altitude profile stored with the navigation data, the height h (s) can be taken from each route point and the gradient dh (s) / ds and thus h (t) / (t) can be determined.

The optimal Auskuppelpunkt AP results in the waypoint where the calculated speed of the current, or for this waypoint in the engaged state estimated vehicle speed corresponds.

As an alternative to this analytical calculation, it is also possible to have one or more optimum decoupling points for the route ahead from the central unit 5 received, wherein the optimal Auskuppelpunkte were determined based on coasting / sailing operations of motor vehicles with similar vehicle characteristics / parameters and depending on the vehicle parameters or relevant parameter parameters k ₀ , k ₁ and k ₂ , see below, are stored.

In step S6, after the end of the coasting process, the estimate of the vehicle parameters relevant to the vehicle is updated from the measured data of this and previous coasting events of the motor vehicle.

der Räder), dem mit der effektiven Stirnfläche multiplizierte Luftwiderstandsbeiwert c_w·A, der fahrzeugabhängige Rollwiderstandskoeffizient c_w,Fzg.With the aid of the above differential equations, the required vehicle parameters of a particular motor vehicle can be estimated from the results of the rolling-down processes of a motor vehicle carried out in different coasting destinations. These are the vehicle mass m _Fzg , the generalized mass m _all (the vehicle mass m _Fzg plus the rotational _{moment of inertia}

the wheels), the coefficient of air resistance c _w · A multiplied by the effective end face, the vehicle- _dependent rolling resistance coefficient c _{w, Fzg} .

vereinfacht sich obige Gleichung zu

und die Kennwerte lassen sich mit vereinfachten Schätzverfahren bestimmen. Die Verwendung der Parameterkennwerte k₀, k₁ und k₂, die eine Form von Fahrzeugparametern darstellen, genügt für die weitere Verwendung im Ausrollassistenten und beschreibt das Verhalten der Fahrzeuge ausreichend.Summarize the parameters as follows

simplifies the above equation too

and the characteristics can be determined using simplified estimation methods. The use of the parameter characteristics k ₀ , k ₁ and k ₂ , which represent a form of vehicle parameters, is sufficient for further use in the coasting assistant and adequately describes the behavior of the vehicles.

The currently existing or estimated values can be used for the route parameters of the individual coasting target points, even if these are still subject to inaccuracies. By evaluating many Ausrollvorgänge to different Ausrollzielpunkten errors out of individual discharge measurements, inaccurate altitude profiles or inaccurate route parameters at individual destinations out.

If many coasting processes are already available, then, to increase the quality of the estimation of the vehicle parameters, it is also possible to evaluate only coasting events of coasting destinations whose route parameters already have a high degree of accuracy or quality.

• • Geschwindigkeit am Auskuppelpunkt AP
• • Geschwindigkeit am Ausrollzielpunkt ZP
• • Geografische Positionen des Auskuppelpunkts und des Ausrollzielpunkts;
• • einer Länge der Ausrollstrecke (z. B. aus Navigationsdaten)
• • einer Höhenänderung über die Ausrollstrecke (z. B. aus Navigationsdaten)

The vehicle parameters can z. B. from the following rollover data are determined as measured data of Ausrollmessungen taking into account the route parameters:

• • Speed at disengaging point AP
• • Speed at coasting point ZP
• • Geographical positions of the dome point and the roll out point;
• • a length of the coasting route (eg from navigation data)
• A height change over the coasting path (eg from navigation data)

It is also possible to determine the vehicle parameters by evaluating the route, speed and acceleration curves between the disengaging point and the coasting target point.

The quality or the accuracy of the estimated vehicle parameters may, for. B. based on the deviation of the calculated with the currently estimated vehicle parameters speed in Ausrollzielpunkt and actually measured at the Ausrollzielpunkt speed and / or the dispersion of the deviation over different Ausrollvorgänge.

Also, in situations with possible parameter changes such as a change in the number of persons of the load and the like, the estimation quality can be temporarily decreased until it could be confirmed that no parameter change took place or the parameters were re-estimated. This can be initiated, for example, by opening vehicle doors or boot flaps. This quality information of the vehicle parameters can in turn be provided in the estimation method for determining the route parameters.

Alternatively, the vehicle _parameters m _FZg , m _all c _w · A and c _{w, Fzg.} be calculated from the parameter characteristics k0, k1 and k2 and the rotational moment of inertia Θ to z. B. driving functions such as vehicle dynamics control, driving stability programs (ESP) or an acceleration-based vehicle monitoring available.

The estimation of the vehicle parameters may be either by a central database function in a cloud application or by providing the route parameters of the coast targets in the control unit 2 of the motor vehicle.

In step S7, the determination of the route parameters can be carried out independently of the estimation of the vehicle parameters. The estimation of the route parameters takes place under the assumption of specified vehicle parameters. In contrast to the vehicle parameters for this purpose, the rollover measurements of several vehicles are evaluated at a single Ausrollzielpunkt. This can only be done with the help of the common database in the cloud application.

• – Δh_Api: Höhenkorrekturwert für verschiedene Auskuppelpunkte AP. Vereinfachend kann für jeden Ausrollvorgang nur die Höhenabweichung zwischen Auskuppelpunkt und Ausrollzielpunkt betrachtet werden und angenommen werden, dass der zu ermittelnde Höhenfehler gleichmäßig über die Ausrollstrecke zwischen dem Auskuppelpunkt und dem Ausrollzielpunkt verteilt ist. Durch Auswertung der Ausrollvorgänge mit Beginn in verschiedenen Auskuppelpunkten kann insgesamt der Höhenverlauf vor dem Ausrollzielpunkt geschätzt und korrigiert werden.
• – c_r,FB: fahrbahnabhängiger Korrekturwert des Rollwiderstandskoeffizienten
• – ν₀: Windgeschwindigkeit in bzw. entgegen der Fahrtrichtung. Die Windgeschwindigkeit kann separat für jeden Ausrollzielpunkt und jede Fahrtrichtung bestimmt werden.
• – ρ_Luft: Die Luftdichte kann geschätzt oder vereinfacht auch nur als Funktion der Höhe betrachtet werden und muss somit nicht geschätzt werden, sondern kann ausreichend genau für jeden Ausrollzielpunkt direkt aus den gespeicherten Höhenwerten bestimmt werden.

The following values can be estimated:

• Δh _Api : altitude correction value for different decoupling points AP. For simplicity, only the height deviation between Auskuppelpunkt and Ausrollpunktpunkt can be considered for each Ausrollvorgang and assume that the height error to be determined is distributed uniformly over the Ausrollstrecke between the Auskuppelpunkt and the Ausrollpunktpunkt. By evaluating the Ausrollvorgänge beginning in different Auskuppelpunkten total of the height profile can be estimated before the Ausrollzielpunkt and corrected.
• - c _{r, FB} : lane-dependent correction value of the rolling resistance coefficient
• - ν ₀ : wind speed in or against the direction of travel. The wind speed can be determined separately for each coasting destination and each direction of travel.
• - ρ _Air : The air density can be estimated or simplified also considered only as a function of altitude and thus need not be estimated, but can be determined sufficiently accurately for each Ausrollzielpunkt directly from the stored altitude values.

For evaluation of the coasting tests, the currently estimated vehicle parameters are used, even if they are still inaccurate. By evaluating a variety of vehicles errors can be reduced by means. Rolling operations of vehicles with poor estimation quality of the vehicle parameters may not be considered.

To get an accurate height correction, the estimation of .DELTA.h _APi over many Ausrollvorgänge can also be carried out over a longer period. Should a change z. B. due to road construction measures, a re-estimate can be triggered when the speed of a Ausrollzielpunkt do not match the desired and previously calculated target speeds over a larger number of vehicles with vehicle parameters with high estimation quality.

If the quality of the estimated height corrections is sufficiently good, only coasting events from a shorter time period can be used to estimate the current average wind speed v ₀ and the road-surface-dependent correction value of the rolling resistance coefficient c _{r, FB} depending on the frequency of the transmitted coasting events. For the single measurement and for the estimation over several measurements in one period, ν ₀ and c _{r, FB are} considered constant. The detection of the temporal change results from the adaptation of the evaluation period.

The quality or the accuracy of the estimated route parameters can, for. For example, based on the average deviation of the measured target speed from the predicted speed in the coasting target point and / or the dispersion of the deviation over different coasting events of different vehicles in this coasting target point. Ausrollzielpunkte with sufficiently accurate track parameters can then be provided with a quality status, so that the Ausrollzielpunkt is particularly suitable for the described estimation of the vehicle parameters.

In step S8, the database with the possible coasting targets / sailing points from the central processing unit 5 be adapted by evaluating coasting / sailing operations of many vehicles. Thus, further Ausrollzielpunkte can be inserted on the route, if there is often initiated by drivers themselves a coast / sail process or it can Ausrollzielpunkte resulting from traffic regulations, traffic situations and / or the height profile are removed, for example because a target speed often falls below the Ausrollfunktionen of a variety of vehicles or the rollout is usually canceled because, for example, a construction site obstructs the Ausrollvorgang.

Claims (15)

Method for operating a motor vehicle ( 1 ) with a coasting / sailing function, wherein the coasting / sailing function is an opening of a drive train ( 8th ) from a decoupling point (AP) to a coasting destination point (AZ), comprising the following steps: determining (S3) a particular next preceding coasting destination (AZ) based on a most likely traveled route and a geographical position of the motor vehicle ( 1 ); - Receiving (S4) from at least one route parameter for the preceding Ausrollzielpunkt (ZP) from external; Determining (S6) an outcoupling point (AP) for the preceding coasting target point (ZP) using the coasting / sailing function based on the at least one route parameter. The method of claim 1, wherein for determining the decoupling point (AP) an equation of motion is evaluated based on an energy or performance comparison between searched Auskuppelpunkt (AP) and desired Ausrollzielpunkt (ZP). Method according to one of claims 1 to 2, wherein the at least one route parameter indicates a parameter related to a route section between a disengaging point (AP) and the preceding coasting destination point (ZP), in particular a height correction value for various possible disengaging points (AP) on the Track section for correcting a height profile before the coasting target point (ZP), a road-surface-dependent correction value of the rolling resistance coefficient, which is predetermined for the track section, a wind speed on the track section in the direction of travel of the motor vehicle ( 1 ) and an air density of the ambient air along the route section. Method according to one of claims 1 to 3, wherein after driving on a section of track with activated coast / sail function, a coasting indication of driving on the section of track is transmitted externally, Method according to Claim 4, in which only coasting data are evaluated for those coasting events in which the speed at the coasting out point (ZP) corresponds to a desired speed or deviates from it by not more than a predetermined tolerance amount. Method according to one of claims 1 to 5, wherein the at least one distance parameter is determined from one or more of the following coasting data for one or more coasting events in a coasting point (ZP): a speed at the decoupling point (AP); A speed at the coasting out point (ZP); A geographical position of the disconnection point (AP); A geographical position of the coasting point (ZP); A length of the coasting distance; A height change over the coasting distance; - Course, speed and / or acceleration curves between the Auskuppelpunkt (AP) and the Ausrollzielpunkt (ZP); - Vehicle parameters assumed to be known. Method according to one of claims 1 to 6, wherein at least one vehicle parameter for the calculation of the Auskuppelpunktes for the preceding Ausrollzielpunkt (ZP) is used, wherein the at least one vehicle parameter from several trips with activated coast / sail function is determined to one or different Ausrollzielpunkten. The method of claim 7, wherein the at least one vehicle parameter specifies a parameter that is related to the motor vehicle ( 1 ), and in particular a vehicle mass, the generalized mass, the vehicle mass and a moment of inertia of rotation

of the wheels, comprises an air resistance coefficient multiplied by the effective end face and / or a vehicle-dependent rolling resistance coefficient. Method according to one of claims 7 to 8, wherein the at least one vehicle parameter from one or more of the following rolling data for one or more coasting events of the motor vehicle ( 1 ) is determined: a speed at the decoupling point (AP); A speed at the coasting out point (ZP); A geographical position of the disconnection point (AP); A geographical position of the coasting point (ZP); A length of the coasting distance; A height change / height profile over the coasting distance; - Course, speed and / or acceleration curves between the Auskuppelpunkt (AP) and the Ausrollzielpunkt (ZP). - The track parameters assumed to be known. Method according to one of claims 7 to 9, wherein the determination of the at least one vehicle parameter in the motor vehicle ( 1 ) or after transmission of a coasting indication of driving on the section of track external to the motor vehicle ( 1 ) is carried out. Method according to one of claims 7 to 10, wherein for determining the at least one vehicle parameter only the coasting events are evaluated in which the speed at the Ausrollzielpunkt corresponds to a desired speed or deviates from this by no more than a predetermined tolerance amount. Method according to one of claims 7 to 11, wherein for the determination of the at least one vehicle parameter only coasting operations are used in sections whose route parameters are known with sufficient accuracy or have a high quality. Device for operating a motor vehicle ( 1 ) with a coasting / sailing function, wherein the coasting / sailing function is an opening of a drive train ( 6 ) from a disengaging point (AP) to at least one coasting destination point (ZP), the device being configured to: - a particular next preceding coasting destination (ZP) based on a most likely traveled route and a geographical position of the motor vehicle ( 1 ) to investigate; To receive externally at least one route parameter for the preceding coasting destination (ZP); To determine a decoupling point (AP) for the preceding coasting target point (ZP) by means of the coasting / sailing function based on the at least one route parameter. Computer program adapted to carry out all the steps of a method according to one of Claims 1 to 13. A machine-readable storage medium having stored thereon a computer program according to claim 15.

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