DE102016011411A1 - Method for operating a drive train of a motor vehicle - Google Patents

Abstract

The invention relates to a method for operating a drive train (34) of a motor vehicle (10), comprising the steps:
- Predictive determination of a relative to an initial speed (22) lower, future target speed (24) of the motor vehicle (10);
- Predictive determination of a lying ahead of the motor vehicle (10) to reach the target speed (24) distance to be covered and a route profile of the route;
Depending on the target speed (24), the distance and the route profile: determining an operating strategy to be carried out during the travel of the route profile and comprising at least one coasting phase of the motor vehicle (10), on the basis of which the drive train (34) effects the at least one coastdown phase is operated such that the motor vehicle (10) after traveling the distance has the target speed (24).

Description

The invention relates to a method for operating a drive train of a motor vehicle, in particular of a commercial vehicle.

From the DE 199 61 720 A1 a method for controlling the speed of a motor vehicle with a drive motor and a braking device is known, wherein the method is activated by the driver in order to maintain the driving speed of the motor vehicle at a predetermined desired speed.

Furthermore, the DE 10 2013 009 279 A1 a method for operating a at least one first drive unit and a second drive unit comprising hybrid powertrain of a vehicle, wherein an operating strategy for the hybrid powertrain is determined in dependence on a route profile lying ahead.

Furthermore, the DE 10 2014 019 543 A1 to derive a method for operating a drive train of a vehicle as known, wherein an operating strategy for the drive train is determined in dependence on a route profile lying ahead. By means of a prediction simulation, at least one velocity trajectory of the vehicle for the preceding route profile is predicted.

Finally, the reveals DE 10 2009 040 682 A1 a method for controlling a cruise control system of a vehicle. Depending on a characteristic vehicle situation determined from route parameters and vehicle parameters, a vehicle speed is set automatically by means of a plurality of alternative control variants by controlling and / or regulating a drive train and / or a braking device of the vehicle.

Object of the present invention is to provide a method for operating a drive train, so that a particularly efficient operation of the drive train can be realized.

This object is achieved by a method having the features of patent claim 1. Advantageous embodiments with expedient developments of the invention are specified in the remaining claims.

The method according to the invention for operating a drive train of a motor vehicle, in particular a utility vehicle, comprises a first step in which, in particular by means of an electronic computing device, for example of the motor vehicle, a future target speed of the motor vehicle that is lower than an initial speed is determined in a forward-looking manner. The output speed of the motor vehicle is, for example, the current driving speed of the motor vehicle, which has the current driving speed, for example at a time or during a time period at which or during which the future target speed is determined. The target speed is a future speed that the motor vehicle currently does not have, but should have or should have in the near future. By predictive determination is to be understood that the target speed is determined at a first time or during a first time period, the motor vehicle is to be brought to the target speed, so that the motor vehicle, the target speed at a second time following the first time or during a to the first period of time following second period of time or should have.

The target speed depends, for example, on an event ahead of the motor vehicle, wherein the motor vehicle has not yet reached the preceding event at the first time, but will reach the second time with a high probability. The method is carried out, for example, during a journey of the motor vehicle, so that the drive train is operated by means of the method during the drive of the motor vehicle. The preceding event is, for example, an event which currently does not affect the drive of the motor vehicle but from the second time point or during the second time span. By way of example, the event is a driving or traffic condition, wherein the event comprises, for example, a route such as a curve and / or an intersection and / or a speed limit, which is, for example, a statutory speed limit. By predictive determination is to be understood in particular that the event is detected or detected before the motor vehicle has actually reached the event and thus before the event applies to the motor vehicle or before the event actually affects the driving of the motor vehicle. As a result, as will be explained in more detail below, it is possible for the drive train, in particular its operation, to be adapted to the preceding event before the motor vehicle actually reaches the event.

The inventive method comprises a second step, in which, in particular by means of the electronic computing device, a the motor vehicle lying ahead, to be covered by the motor vehicle until reaching the target speed distance and a route profile of the route are determined in advance. For example, a current, first position of the motor vehicle and a preceding second position, in which the motor vehicle is to have the target speed, determined. Further, a distance between the positions is determined, wherein the distance corresponds to the distance, for example. The route profile characterizes, for example, the topography and thus a height profile of the route, so that the route profile includes, for example, any existing gradients and / or climbs. The distance thus corresponds to a roadway or road section ahead of the motor vehicle, which the motor vehicle has covered or has to cover until reaching the event and thus the target speed. The route to be covered by the motor vehicle until the event and thus the target speed are reached and the route profile of the route are determined in a forward-looking manner, so that the route and the route profile are determined before the motor vehicle actually reaches or has traveled the route and the route profile. In this way, the drive train, in particular its operation, can be adapted to the distance to be covered up to the event or the target speed and its route profile before the motor vehicle actually travels the route and thus the route profile.

The inventive method further comprises a third step, in which, in particular by means of the electronic computing device, depending on the target speed, the distance and the route profile during the covering of the route profile having path to be performed and at least one coasting phase of the motor vehicle comprehensive operating strategy is determined, on the basis of which the drive train is operated so as to effect the at least one coastdown phase such that the motor vehicle actually has the target speed after covering the distance and thus at the aforementioned second position. In other words, the drive train is operated by means of the operating strategy such that the motor vehicle at or from the second position has a travel speed which corresponds to the target speed. The operating strategy is preferably determined as an energy or fuel consumption optimal operating strategy, so that the motor vehicle can be brought from the initial speed during the travel of the route particularly efficient and thus energiegünstig to the lower target speed compared to the starting speed. In this case, the operating strategy is preferably determined in such a way that the motor vehicle travels the route as far as possible to reach the target speed or the event as energy-efficiently and as quickly as possible, so that a loss of time caused by the operating strategy can be avoided or kept to a minimum.

The coasting phase is also referred to as coasting, Ausrollvorgang, rolling or rolling phase, wherein during the Ausrollvorgangs effected by the drive train driving and preferably caused by a braking device of the motor vehicle braking of the motor vehicle omitted. The rolling out occurs, for example, with a closed drive train and thus, for example, with a drag torque, which from a trained example as an internal combustion engine drive motor of the motor vehicle on the wheels on which the motor vehicle rolls during the travel of the route on a roadway, acts. Further, it is conceivable that the rolling out with the drive train open and thereby, for example, with the clutch open and / or idling, so that no drag torque acts on the wheels of the drive motor. By acting on the wheels drag torque an engine brake is realized, whereby the motor vehicle is braked by means of the drive motor.

Since, in the context of the method according to the invention, the drive train, in particular its operation, is adapted to the target speed or to the event defining the target speed before the motor vehicle actually reaches the event, a predictive driving strategy for controlling a cruise control can be realized by means of the method according to the invention. by means of which the motor vehicle can be brought to the target speed in a particularly energy-efficient manner. This predictive driving strategy is the aforementioned operating strategy, in the context of which, for example, a gear specification and optionally a torque distribution between the example designed as an internal combustion engine drive motor and at least one further, designed as an electric machine drive motor, so that the motor vehicle during the travel of the route particularly energy efficient by performing the at least one coastdown phase is brought from the initial speed to the comparatively lower target speed. The event specifying the target speed is, for example, an obstacle or an area for which the target speed applies.

It has proven to be particularly advantageous if, during the execution of the operating strategy, an increase in the speed of the motor vehicle caused by a drive device of the motor vehicle does not occur. Thus, the operating strategy is determined such that the motor vehicle by means of the drive train does not have to be positively accelerated, but preferably the achievement of the target speed is achieved only by rolling and optionally by at least one by means of a braking device of the drive train or the motor vehicle effected braking. As a result, the energy consumption of the motor vehicle can be kept particularly low.

A further embodiment is characterized in that a position from which the coasting phase is started is determined or set as a function of the target speed, the route and the route profile. This is to be understood as meaning that a location or a point in time at which the motor vehicle can or must roll out is determined in order to have reached the desired target speed when the event has been reached. The achievement takes place for example by a constant speed change.

The respective predictive determination is also referred to, for example, as foresight, which is performed, for example, by means of the electronic computing device, which is also referred to as the control device. In particular, the operating strategy is determined by means of the forecast in dependence on all essential parameters in order to achieve the target speed in a particularly energy-efficient manner.

In a further advantageous embodiment of the invention, the operating strategy is carried out as a function of at least one predefinable or predetermined path condition and / or as a function of at least one predefinable or predetermined speed condition. The route condition includes, for example, that the distance to be covered is less than a maximum distance. The speed condition includes, for example, that the output speed is greater than a maximum speed, in particular, a maximum roll speed.

It has been found to be particularly advantageous if the path condition and / or the speed condition as a function of the initial speed and / or as a function of a traffic situation and / or depending on a driving behavior and / or a driving type of the driver of the motor vehicle and / or depending on a load of the motor vehicle and / or depending on a type of road on which the motor vehicle is located is set.

A further embodiment is characterized in that, as part of the operating strategy, the motor vehicle is braked, at least temporarily, by means of at least one braking device of the drive train or of the motor vehicle. In particular, the operating strategy is designed such that the driving speed of the motor vehicle does not fall below a lower limit. To avoid this, for example, at least one braking operation is performed.

In a further advantageous embodiment of the invention, it is provided that the coasting phase is maximally carried out until a difference between the initial speed and a driving speed of the motor vehicle caused by the coasting phase reaches a predefinable value. In other words, it is preferably provided that the coasting phase is executed maximally up to a predefined rolling speed difference from the original initial speed.

It has proven to be particularly advantageous if the value as a function of the initial speed and / or as a function of a traffic situation and / or depending on a driving behavior and / or a driving type of the driver of the motor vehicle and / or depending on a load of the motor vehicle and / or depending on a type of road on which the motor vehicle is located is set.

In a further embodiment of the invention, a maximum route length is scheduled for the coasting phase and checked after scheduling for compliance with a maximum allowable time for performing the coasting phase. In other words, the rolling phase is set to a maximum route length and checked after planning on the compliance of the maximum allowed time, which is also referred to as roll time.

Finally, it has proven to be advantageous if the maximum route length and / or the maximum permissible time as a function of the initial speed and / or as a function of a traffic situation and / or depending on a driving behavior and / or a driving type of the driver of the motor vehicle and / or depending on a load of the motor vehicle and / or depending on a type of road on which the motor vehicle is located is set.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or in the figures alone can be used not only in the respectively indicated combination but also in other combinations or in isolation, without the scope of To leave invention.

The drawing shows in:

1 a diagram illustrating a method according to the invention for operating a drive train of a motor vehicle;

2 another diagram illustrating the method;

3 a schematic representation of an apparatus for performing the method;

4 another diagram illustrating the method;

5 another diagram illustrating the method;

6 another diagram illustrating the method; and

7 a flowchart illustrating the method.

In the figures, the same or functionally identical elements are provided with the same reference numerals.

1 shows a diagram, based on which in the following a method for operating a drive train of a vehicle designed as a commercial vehicle 10 is described. On the abscissa 12 of the diagram is plotted a path s, that of the motor vehicle 10 is covered. Further, on the ordinate 14 plotted a speed v of the diagram, wherein the motor vehicle 10 has the vehicle speed v. Thus, one in the diagram of 1 registered history 16 the driving speed of the motor vehicle 10 when traveling the distance s, which is also referred to as a path.

By means of an electronic computing device of the motor vehicle 10 For example, the method and in the context of the method a forecast is performed, in the course of which at least one of the motor vehicle 10 preceding event 18 and especially one by the event 18 caused or predetermined target speed is determined at a time at which the motor vehicle 10 the event 18 has not yet reached, but still in the forward direction of the motor vehicle 10 before the event 18 located. At the event 18 In the present case, this is, for example, a speed limit prescribed by law, which is the driver of the motor vehicle 10 through a road sign 20 is visually communicated. As part of the forecast, the road sign 20 and thus the event 18 as well as the corresponding target speed determined or detected, for example, at a first time or during a first time period. The car 10 however, has the event at this first time 18 not yet reached, but becomes the event 18 until a later second time following the first time. In the context of the forecast the event will be 18 for example, detected while the motor vehicle 10 is located at a first position on the earth or along the distance s.

The method is during a journey of the motor vehicle 10 carried out, which moves as part of the journey along the route s. The route s extends for example along a roadway on which the motor vehicle 10 rolls over his wheels. The event 18 However, located at a different from the first position, the motor vehicle 10 lying second position on the ground or along the route s. Thus, in the framework of foresight, the event 18 captured before the motor vehicle 10 the event 18 actually achieved. In other words, the event 18 and thus detects the target speed in the context of the forecast before the target speed of the drive of the motor vehicle 10 influenced or before the target speed for the motor vehicle 10 applies.

The method comprises a first step, in which the compared to an initial speed 22 of the motor vehicle 10 lower, future and in 1 With 24 designated target speed is determined in advance by means of the electronic computing device. The initial speed 22 is, for example, the current driving speed of the motor vehicle 10 which has the current vehicle speed at a time or at the first time at which the target speed 24 is determined in a forward-looking manner. The target speed applies, for example, to an area, wherein the anticipatory determination of the target speed is to be understood as meaning that the target speed or the area in which the target speed is valid is determined before the motor vehicle 10 actually reached the area Has. As the target speed and thus the area the motor vehicle 10 lie ahead exists between the motor vehicle 10 and the event 18 or the area a distance, which one of the motor vehicle 10 until reaching the event 18 and thus corresponds to the target speed traveled distance. In a second step of the method, in particular by means of the electronic computing device, these are lying ahead of the motor vehicle 10 Determined to reach the target speed distance to be anticipated. Furthermore, a route profile of the route is determined in advance. Under the route profile, for example, a height profile and / or a course of the distance to be covered to understand so that the route profile, for example, any increases and / or gradients and / or curves and / or traffic conditions and / or traffic situations includes the route. Furthermore, it is conceivable that the event 18 , in particular legal, speed limits and / or road courses such as intersections or curves.

The event 18 , the route and the route profile are determined, for example, based on a map-based forecast and thus on the basis of a map-based forecast horizon. For this purpose, the motor vehicle includes 10 For example, a navigation device, in the memory card data are stored. The map data characterize, for example, a virtual map of at least one, for example the motor vehicle 10 lying ahead, portion of the environment of the motor vehicle 10 , By means of the navigation device, for example, in particular by means of a satellite-based positioning system such as GPS (Global Positioning System), a current position of the motor vehicle 10 destined on earth. Further, based on the map data or virtual map, a position of the event 18 certainly. By determining the position of the motor vehicle 10 on earth can be a position of the motor vehicle 10 be determined with respect to the virtual card, so that finally a position of the motor vehicle 10 with respect to the example noted in the virtual card event 18 can be determined. This allows the distance and thus of the motor vehicle 10 until reaching the event 18 distance to be traveled and their route profile are determined. Furthermore, it is possible, for example, along the route to be traveled prevailing traffic and / or weather situations and / or other, the drive of the motor vehicle 10 to influence possibly influencing driving conditions, which may be components of the route profile or conditions present in the environment.

At a third step of the procedure will depend on the target speed 24 determining the route and the route profile, in particular by means of the electronic computing device, an operating strategy to be carried out during the covering of the route profile and comprising at least one coasting phase of the motor vehicle, on the basis of which the drive train is operated by effecting the at least one coasting phase such that the motor vehicle 10 After covering the distance and thus on reaching the event 18 or upon reaching the area for which the event 18 is valid, the target speed 24 having.

The target speed 24 can for example be determined by a static or adaptive, virtual map. The method is carried out, for example, in the context of a cruise control function, wherein the cruise control function is also referred to as cruise control or Geschwindigkeitstempomat. By means of the cruise control function, for example, the target speed is set automatically, in particular without the driver's intervention, or the motor vehicle 10 is from the initial speed 22 to the target speed 24 automatically brought. The driver can intervene at any time and override the cruise control function, for example by pressing an accelerator pedal and / or a brake pedal and / or a brake lever. If the driver does not intervene in the cruise control function, the motor vehicle becomes 10 from the initial speed 22 For example, by means of the cruise control function automatically to the target speed 24 brought by at least the at least one coastdown phase is performed or effected. The coasting phase is also referred to as coasting, rolling, rolling, rolling or rolling phase. Under the coasting phase is to be understood in particular that during the coasting phase caused by the drive train driving the motor vehicle and in particular caused by the drive train speed increase of the motor vehicle 10 remain under.

Different, preceding events are assigned, for example, different target speeds. For example, if the preceding event includes an intersection in the form of a roundabout, the target speed is, for example, 50 kilometers per hour or less, so starting from the initial speed 22 the car 10 to the target speed of, for example, 50 or 25 kilometers per hour, in particular by rolling, is brought. For example, if a stop sign is provided at the intersection, the target speed is, for example, 10 kilometers per hour. At traffic lights, for example, a submerged Roll out. Includes the event, for example, that the motor vehicle 10 other road users must grant priority, so there is only a slight roll out. For example, if the event includes a toll station, the target speed is 10 kilometers per hour, for example. For example, if the event includes a curve, the target velocity will depend on a learned velocity and / or the curvature of the curve. The cruise control function can be activated and deactivated by the driver and, in particular after its activation, is active until the driver intervenes if necessary.

Furthermore, it is off 1 recognizable that the driver of the motor vehicle 10 by means of at least one advertisement 26 during a pre-Auslaufvorgang the time interval 28 and thus informed of the impending Ausrollvorgang before the start of the Ausrollvorgangs. Alternatively or additionally, the driver by means of the display 26 during the time span 28 about the target speed 24 and their reason, that is, about the event 18 , informs you, before the coasting starts. The driver is thereby by means of the display 26 visually informed by, for example, the ad 26 corresponding symbols are displayed.

As the powertrain, in particular its operation, to the event 18 is adjusted before the motor vehicle 10 the event 18 can reach the energy consumption of the motor vehicle 10 be kept particularly low. In 1 is denoted by E an energy saving, by means of the operating strategy against one by the driver of the motor vehicle 10 carried startup of the motor vehicle 10 to the event 18 can be realized. Furthermore, in 1 a time loss caused by the operating strategy in relation to the approach to the event caused by the driver caused by ZE, the operating strategy is preferably designed so that the travel distance as energy efficient, but also as fast as possible, so that the time loss ZE are kept particularly low can.

2 shows a diagram illustrating phases of the coasting process. It is on the abscissa 30 of in 2 shown diagram, the distance s and the time t plotted, where on the ordinate 32 the driving speed v of the motor vehicle 10 is applied. The phases of the coasting process are in 2 denoted by I, II, III, IV and V. The timespan 28 is in 2 denoted Δt _{before display} . The driver is informed by means of the display 26 at least during the period 28 informed. The driver can do this over the time span 28 be informed, wherein a period during which the driver is informed, in 2 denoted Δt _display . During phase I there is a constant travel of the motor vehicle 10 , wherein the constant travel of the actual, taking place in phase II Ausrollphase anticipates. In phase II, the actual rolling takes place, whereby the rolling can take place with drag torque and thus with a closed drive train or without drag torque and thus with the drive train open. Phase II follows the phase I in time. Phase II is followed by phase III. Phase III is a braking phase with continuous brake and / or service brake. Phase III is followed by phase IV, which is also referred to as STA (Smooth Target Approach). During phase IV, the delay is linearly reduced to the target speed 24 , Phase IV is followed by phase V, during which a constant cruise at the target speed 24 he follows. Furthermore, in 2a a negative acceleration and thus a decrease in speed of the motor vehicle 10 , where with a _drag a speed decrease is referred to, which is moved by the coasting phase, in particular with drag torque and thus closed powertrain and / or without drag torque and thus with an open drive train. The speed _decrease a _drag , for example, by the route profile, in particular by an increase in the distance to be covered. Further, a _brake denotes a speed reduction caused by a braking operation, wherein the braking operation by means of at least one braking device, for example by means of a retarder and / or by means of a service brake, the motor vehicle 10 is effected. Further, a _STA denotes the linear reduction of the deceleration to the target speed. Further, Δt, Δt _max indicate time differences Δs, Δs _max , Δ _STA path differences and Δv and Δv _max speed differences, these differences being explained in more detail below.

3 shows an apparatus for implementing the method, wherein in 3 the drive train of the motor vehicle 10 With 34 is designated. The powertrain 34 includes the aforementioned and with 36 designated wheels, via which the motor vehicle 10 rolling on the road during his ride. Furthermore, the drive train includes 34 Wheel or service brakes for braking the motor vehicle 10 , The powertrain 34 comprises a further braking device in the form of a retarder 38 , by means of which the motor vehicle 10 can be slowed down. Furthermore, the drive train includes 34 at least one designed for example as a diesel engine combustion engine 40 , which is also referred to as an internal combustion engine and for driving the motor vehicle 10 is trained. The internal combustion engine 40 is thus a drive motor for driving the motor vehicle 10 , Furthermore, the drive train includes 34 a trained as a coupling starting element 42 and at least one electric machine 44 , which is operable for example as an electric motor and / or as a generator. By means of the electric machine 44 is for example the motor vehicle 10 drivable. This means, for example, that the electric machine 44 as another drive motor for driving the motor vehicle 10 can be operated.

Furthermore, it is conceivable that the electric machine 44 is operable in a generator mode, in which the electric machine 44 kinetic energy of the motor vehicle 10 converted into electrical energy and provides this electrical energy. Furthermore, the drive train includes 34 an example designed as a lithium-ion battery battery 46 in which electrical energy or electrical current can be stored. The of the electric machine 44 provided electrical energy, for example, in the battery 46 get saved. Furthermore, it is conceivable, the electric machine 44 with in the battery 46 stored electrical energy to thereby the electric machine 44 to operate as an electric motor. It also includes the powertrain 34 a gearbox 48 which has, for example, a plurality of gears with different ratios.

The aforementioned operating strategy is in 3 for example with 50 referred to and designed as a predictive driving strategy for controlling the aforementioned cruise control. Furthermore, for example, in the context of the predictive driving strategy, a gear specification takes place, in the context of which, for example, the respective gear of the transmission 48 is automatically inserted and / or the driver is advised to insert a corresponding gear. Furthermore, as part of the predictive driving strategy is optional torque distribution between the electric machine 44 and the internal combustion engine 40 intended.

In 3 is with 52 denotes a look-ahead horizon module, by means of which, for example, the respective, previously described, predictive determination is performed. The lookahead horizon module 52 For example, using GPS, and thus using GPS positioning and the digital map, creates a look-ahead horizon that, for example, gives the route profile, in particular, a slope and / or curvature profile of the route to travel over a selected horizon length. The horizon length is, for example, a path ahead of the motor vehicle, along which or over which the respective anticipatory determination can take place.

There is also a central powertrain control module 54 provided, which is a speed control module 56 , a shift strategy module 58 and a moment management module 60 includes. The central drive control module 54 , the foresight horizon module 52 and the predictive driving strategy (operational strategy 50 ) are, for example, components of the aforementioned electronic computing device. The speed control module 56 controls a setpoint specified by the driver, is influenced by a variable setpoint speed range on the predictive operating or driving strategy and determines the total required drive and braking torque. The switching strategy module 58 determines the optimal gear of the transmission 48 , is optionally influenced by the predictive or predictive driving strategy and transmits the determined gear to a transmission electronics, by means of which the determined gear, for example, is inserted. The moment management module 60 determines the setpoint torques for the internal combustion engine from the specifications of all control functions 40 (Internal combustion engine), the electric machine 44 , Continuous brakes and service brakes.

In addition, a battery monitoring module 62 optionally provided, which the charge and load condition of the battery 46 determined and this a powertrain control function, in particular the powertrain control module 54 , transmitted. Furthermore, in 3 With 64 an engine electronics, with 66 an optionally provided control electronics of the electric machine 44 , With 68 the aforementioned transmission electronics, with 70 a Dauerbremselektronik for driving retarding, with 72 an operating electronics for driving the service brakes and with 73 denotes a data cloud, which is also referred to as cloud or data cloud. From the data cloud 73 For example, the electronic computing device receives traffic data and thus information about a traffic situation, in particular along the route to be traveled. Furthermore, the electronic computing device from the data cloud 73 Get updates to the virtual map so the route profile and events ahead can always be accurately determined.

By means of the method, a card-based forecast speed-control system and the ability to respond to upcoming and thus upcoming events, such as intersections, tight turns, and / or speed limits, formed as braking events can be realized. Under such a braking event is to be understood that the event is a reduction in the driving speed of the motor vehicle 10 from the initial speed 22 to the target speed 24 requires.

For example, as part of the process, the new target speed 24 adjusted. It is preferably provided that the adjusting the upcoming new target speed 24 first by a backward simulation of the at least one coastdown phase from the position of the event 18 checked and actively implemented when a path condition and / or a speed condition is met. 4 shows a diagram illustrating the method, wherein in the diagram the position of the event 18 is denoted by A. For example, the path condition includes s being less than Δs _{max, Roll} . The speed condition includes, for example, that v is greater than Δv _{max, Roll} . In other words, for example, for the path condition: s <Δs _{max, Roll} . Furthermore, for example, for the speed condition: v> Δv _{max, roll} .

In this case, Δv _{max, Roll} denotes a predefined roll speed difference, where Δs _{max, Roll} denotes a maximum roll distance. The predefined roll speed difference and the maximum roll distance become, for example, dependent on the output speed 22 or from an absolute speed level and / or as a function of a traffic situation and / or as a function of a driving behavior and / or a driving type of the driver of the motor vehicle 10 and / or depending on a load of the motor vehicle 10 and / or depending on a type of road surface on which the motor vehicle 10 is set. In the event that a pure roll phase is not possible, adjusting the upcoming new target speed 24 for example, by a rolling phase with or without drag torque and subsequent braking phase. Under a roll phase with drag torque is to be understood that the powertrain 34 closed, so the wheels 36 which the motor vehicle 10 along the roadway rolls, the internal combustion engine 40 hauling. As a result, an engine brake is realized, for example, whereby a decrease in speed or braking of the motor vehicle 10 is effected. Under a rolling phase without drag torque is a rolling phase in idle or neutral position to understand, with a by the motor vehicle 10 causes dragging of the internal combustion engine 40 omitted.

Furthermore, it is preferably provided that the rolling phase is set to a maximum length of the track Δs _max and, after the planning has been completed, a check is made for compliance with a maximum or maximum permissible roll time Δt _max . Furthermore, it has been shown to be advantageous if the roll time duration Δt _max and / or the roll length Δs _max is or are dependent on the absolute speed level and / or the traffic situation and / or the driver's driving style and / or from the loading of the motor vehicle 10 and / or the type of roadway or road type.

Furthermore, it has proven to be particularly advantageous if the rolling phase maximally reaches a predefined rolling speed difference Δv _max from the original starting speed 22 is performed. By this is meant, for example, that the coasting phase is carried out for a maximum until a difference between the initial speed 22 and a vehicle speed caused by the coasting phase 10 reaches a predefinable value. This value is in 4 _denoted by v _coastmin , the value being given for example, in particular by the driver of the motor vehicle 10 , can be specified. The roll speed difference Δv _max is thus, for example, the aforementioned difference between the output speed 22 and the value v _coastmin , which defines a minimum speed up to which the coast down phase is allowed.

Alternatively or additionally, it is advantageous if the planning of the rolling and subsequent braking phase is carried out by a backward simulation of the braking phase and a subsequent forward simulation of the rolling phase while maintaining the predefined parameter roll time Δt _max , roll length Δs _max and roll speed difference Δv _max becomes. In this case, for example, by means of the display 26 an optical communication of the reason of performing the Ausrollvorgangs, said optical communication takes place a period of time .DELTA.t _{before display} before the activation or start of the Ausrollphase. In 4 For example, the time period Δt _{before display} is dependent on the speed level and / or on the traffic situation and / or on the driving behavior and / or the driving type of the driver and / or on the load of the motor vehicle 10 and / or on the type of roadway or on the type of road.

In the context of the predictive driving strategy, for example, at least one movement trajectory is calculated in the described manner, which is designed as a rolling and / or braking trajectory and is also referred to as a velocity trajectory. Such a movement trajectory describes a calculated driving speed of the motor vehicle 10 or a calculated course of the vehicle speed over time or the way. If the movement trajectory is actually implemented, then the actual temporal or local course corresponds to the driving speed of the motor vehicle 10 the course given by the movement trajectory. The backward-simulated braking trajectory, for example, has a human-behavioral course with a gentle onset, a stronger center, and a comfortable smooth transition to cruise, which smooth transition, for example, is the linear reduction of deceleration to target speed during phase IV 24 is.

Out 4 It can be seen, for example, that the operating strategy fundamentally differentiates between four cases. In this case, the rolling process is illustrated by rolling lines. In the first case, coasting is not enough to reduce the speed when the event is reached 18 at the point A only by rolling out the target speed 24 to reach. This may be the case, for example, if the route or its route profile has a gradient. Then, for example, from a point B, a braking operation is performed, in particular along a braking line BA to the motor vehicle 10 from the initial speed 22 to the target speed 24 bring to.

In a second of the cases, the speed of travel can be easily reduced by coasting. Then, for example, from a point C is started with the rolling until, for example, the braking line is reached. Upon reaching the braking line, a braking operation is then carried out, in the context of which the motor vehicle 10 , in particular active, is braked. In a third of the cases, the speed can be partly strong, sometimes less reduced by rolling out. In this case, the coasting is delayed, so that the _{vehicle speed} remains greater than v _coastmin or at _most falls to v _coastmin . In this case, the rolling is started, for example, from a point C 'and braked from a point F on the braking line. In a fourth of the cases, rolling out reduces the speed too much. Then the coasting is even more delayed until the rolling line intersects the braking line at a point H which is exactly on v _coastmin . Then, for example, from the point C 'started with the roles and from the point H on the braking line is braked. Thus, in FIG 4 courses 74a -C the mentioned rolling lines. In particular, the courses illustrate 74a -C movement trajectories or speed or Ausrolltrajektorien, the courses 74a C is the driving speed v of the motor vehicle 10 while traveling the route. In the process, the drive train is being used by means of the operating strategy 34 so operated, in particular controlled or regulated that the respective speed trajectory is implemented, that is, that the driving speed v of the motor vehicle 10 while traveling the distance until reaching the event 18 (Point A) corresponds to the respective coasting or speed trajectory.

7 shows a flowchart illustrating the method, wherein the flowchart and the method in conjunction of 7 With 4 to 6 be explained in more detail. In a first step S1, a coasting situation in the card horizon is detected in point A. In other words, at the first step S1, the event located at the first position and thus at the point A in the map horizon becomes 18 anticipatory determined. In a second step S2 of the method, the by the event 18 predetermined target speed 24 determined. In a third step S3, a backward simulation of the coasting process with the speed _decrease a _drag from the point A to the point B 'is carried out, taking into account in particular the topography or the route profile and any other influencing variables. In a fourth step S4, a decision or a check is made. In the fourth step S4 it is checked whether Δv is greater than Δv _{max, Roll} . Further, at the fourth step S4, it is checked if s is larger than ΔS _{max, Roll} . In other words, in the fourth step S4, the following conditions are checked: Δv> Δv _{max, roll} s> Δs _{max, roll}

If, for example, both conditions are not met or if at least one of the conditions is not fulfilled, a corresponding rolling trajectory is implemented at a fifth step S5 by means of the operating strategy, so that the coasting process is started at point B ', for example, and the motor vehicle 10 starting from the point B 'on reaching the point A, the target speed 24 has, which, in particular automatically, achieved by implementing the Rolltrajektorie or by the rolling. The rolling trajectory is also referred to as rolling trajectory.

If both conditions are met in the fourth step S4, for example, in a sixth step S6, a backward simulation of the braking process takes place from the point A to the point B taking into account the topography and any other influencing variables. At a seventh step S7, the point C is then determined as a roll start point by going backwards by Δ _max from the point B. The roll start point is to be understood as meaning a point or a position at which the coasting process is started.

At an eighth step S8, a forward simulation with drag torque from the point C taking into account the topography and any other factors. In a ninth step S9 is a particularly well based on 5 recognizable case distinction. Out 7 It can be seen that steps S6, S7, S8 and S9 as well as the case discrimination performed at step S9 are performed when both conditions are satisfied at the fourth step S4.

The case distinction distinguishes between the above four cases F1, F2, F3 and F4. The first case F1 includes, for example, an in 5 recognizable coasting trajectory 76 , which are above the initial speed 22 where it is the coasting trajectory 76 For example, it comes from the fact that the distance to be covered includes a slope or at least one gradient. The second case F2 includes an in 5 shown coasting trajectory 78 cutting the line AB above V _coastmin . The third case F3 includes an in 5 shown coasting trajectory 80 which intersects the line AB, but is partially below v _coastmin . As described _above , v _{coastmin is} a lower limit, and the coasting is maximally performed up to this lower limit or so that the vehicle speed v falls at most to the lower limit. The fourth case F4 includes an in 5 shown coasting trajectory 82 which are below the point A or below the target speed 24 falls, which is caused for example by a slope.

In the first case F1 a rolling phase is not possible, so that by means of the operating strategy of the powertrain 34 is operated, for example, such that at a tenth step S10 from the point B, a braking operation, that is, the motor vehicle 10 is slowed down. In the second case F2 is the coasting trajectory 78 suitable for the motor vehicle 10 upon reaching point A and thus the event 18 the target speed 24 when the coasting trajectory 78 carried out or implemented. It is off 5 recognizable that the coasting trajectory 78 at least one coastdown phase and an adjoining braking phase during which a braking operation is performed, so that the motor vehicle 10 braked during braking, here along the line FA. Thus, in the second case F2 becomes the coasting trajectory 78 implemented at an eleventh step S11.

In the third case F3, at a twelfth step S12, the roll-starting point becomes so long along the abscissa 30 shifted to the right until the coasting trajectory 80 above v _coastmin the line AB at the point F intersects what is in 6 through arrows 84 is illustrated. By this shifting the coasting trajectory 80 gets off the coasting trajectory 80 the coasting trajectory 80 ' which is then actually implemented, for example, at the twelfth step S12.

In the fourth case F4, for example, at a thirteenth step S13, the roll start point is shifted from the point C to the point C 'and then right until the point H is reached, or until the coasting trajectory 82 the brake line BA in the present case intersects in the point H, so that from the coasting trajectory 82 the coasting trajectory 82 ' becomes.

The eleventh step S11 and the twelfth step S12 are followed, for example, by a fourteenth step S14. At the fourteenth step S14, it is checked whether the coasting phase is completed within Δt _max . If this is not the case, then the roll start point is moved further to the right. The thirteenth step S13 is followed by a fifteenth step S15, which also follows the fourteenth step S14. At the fifteenth step S15, a downstream consideration is made as to whether a so-called EcoRoll can be introduced. Under such an EcoRoll is, for example, a coasting phase without drag torque, that is with the drive train open 34 and thus, for example, idle, provided.

LIST OF REFERENCE NUMBERS

10

motor vehicle

12

abscissa

14

ordinate

16

course

18

event

20

road sign

22

output speed

24

target speed

26

display

28

Period of time

30

abscissa

32

ordinate

34

powertrain

36

wheel

38

retarder

40

internal combustion engine

42

starting element

44

electric machine

46

battery

48

transmission

50

operating strategy

52

Forward-looking horizon module

54

central powertrain control module

56

Cruise control module

58

Shift strategy module

60

Moment management module

62

Battery monitoring module

64

engine electronics

66

control electronics

68

transmission electronics

70

Continuous braking electronics

72

Service brake electronics

73

data cloud

74a-c

course

76

Ausrolltrajektorie

78

Ausrolltrajektorie

80, 80 '

Ausrolltrajektorie

82, 82 '

Ausrolltrajektorie

84

arrows

e

energy savings

F1

first case

F2

second case

F3

third case

F4

fourth case

S1

first step

S2

second step

S3

Third step

S4

fourth step

S5

fifth step

S6

sixth step

S7

seventh step

S8

eighth step

S9

ninth step

S10

Tenth step

S11

eleventh step

S12

twelfth step

S13

thirteenth step

S14

Fourteenth step

S15

fifteenth step

ZE

loss of time

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19961720 A1 [0002]
• DE 102013009279 A1 [0003]
• DE 102014019543 A1 [0004]
• DE 102009040682 A1 [0005]

Claims (10)

Method for operating a drive train ( 34 ) of a motor vehicle ( 10 ), comprising the steps: - Predictive determination of a relative to an initial speed ( 22 ) lower, future target speed ( 24 ) of the motor vehicle ( 10 ); - Predictive determination of a preceding, of the motor vehicle ( 10 ) until reaching the target speed ( 24 ) distance to be covered and a route profile of the route; - depending on the target speed ( 24 ), the route and the route profile: determining a route to be performed during the travel of the route profile having the route profile and at least one coasting phase of the motor vehicle ( 10 ) comprehensive operating strategy on the basis of which the powertrain ( 34 ) is operated while causing the at least one coast down phase such that the motor vehicle ( 10 ) after covering the distance the target speed ( 24 ) having. A method according to claim 1, characterized in that during the execution of the operating strategy by a drive means of the motor vehicle ( 10 ) caused increase in the speed of the motor vehicle ( 10 ) is omitted. A method according to claim 1 or 2, characterized in that a position from which the coasting phase is started, depending on the target speed ( 24 ), the route and the route profile is determined. Method according to one of the preceding claims, characterized in that the operating strategy is carried out as a function of a predefinable travel condition and / or as a function of a predefinable speed condition. A method according to claim 4, characterized in that the path condition and / or the speed condition in dependence on the initial speed ( 22 ) and / or depending on a traffic situation and / or depending on a driving behavior and / or a driving type of the driver of the motor vehicle ( 10 ) and / or depending on a load of the motor vehicle ( 10 ) and / or depending on a type of roadway on which the motor vehicle ( 10 ) is set. Method according to one of the preceding claims, characterized in that in the context of the operating strategy the motor vehicle ( 10 ) at least temporarily by means of at least one braking device of the motor vehicle ( 10 ) is slowed down. Method according to one of the preceding claims, characterized in that the coasting phase is carried out a maximum until a difference between the initial speed ( 22 ) and a vehicle speed caused by the coasting phase ( 10 ) reaches a predefinable value. Method according to claim 7, characterized in that the value depends on the initial speed ( 22 ) and / or depending on a traffic situation and / or depending on a driving behavior and / or a driving type of the driver of the motor vehicle ( 10 ) and / or depending on a load of the motor vehicle ( 10 ) and / or depending on a type of roadway on which the motor vehicle ( 10 ) is set. Method according to one of the preceding claims, characterized in that a maximum route length is planned for the coasting phase and after scheduling for compliance with a maximum permissible time for carrying out the coasting phase is checked. Method according to Claim 9, characterized in that the maximum route length and / or the maximum permissible time as a function of the initial speed ( 22 ) and / or depending on a traffic situation and / or depending on a driving behavior and / or a driving type of the driver of the motor vehicle ( 10 ) and / or depending on a load of the motor vehicle ( 10 ) and / or depending on a type of roadway on which the motor vehicle ( 10 ) is set.

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