DE102013009279A1 - Method and apparatus for operating a hybrid powertrain of a vehicle - Google Patents

Abstract

The invention relates to a method for operating a hybrid drive train (2) of at least one first drive unit (2.1) and a second drive unit (2.2) of a vehicle (1), an operating strategy for the hybrid drive train (2) depending on a preceding route profile (SP). is determined. According to the invention, a speed trajectory (vT, vT1, vT2) of the vehicle (1) for the preceding route profile (SP) is predicted by means of a look-ahead simulation Determined position on the route profile (SP) by means of a second drive unit (2.2) of the hybrid drive train (2) designed as an electric motor generates a braking torque and an electrical energy generated in this way is stored in an energy storage unit (2.4) of the hybrid drive train (2) that at least the The amount of exceeding the target speed corridor (ZK) is reduced or the crossing of the target speed corridor (ZK) is avoided. The invention further relates to a device (3) for carrying out the method.

Description

The invention relates to a method for operating a hybrid drive train of a vehicle, wherein an operating strategy for the hybrid drive train is determined as a function of a preceding route profile.

The invention further relates to a device for carrying out the method.

In cruise control systems of vehicles often a so-called hysteresis is defined around a preset target speed around by the target speed is no longer controlled exactly by interventions in the target torque of the drive units of the vehicle or by interfering with a brake system of the vehicle, but the vehicle in a coasting with Engine drag rolls. With suitable topography of a route profile on which the vehicle is moving, this leads to fuel-saving effects. Due to the hysteresis range, a target speed corridor is formed.

Such a method for controlling a cruise control system of a vehicle describes the DE 10 2009 040 682 A1 in which, 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 regulating a drive train and a braking device of the vehicle. The route parameters, which comprise at least slope data, are currently determined from at least one road section ahead of three-dimensional map data of a digital road map, one or more suitable depending on the route parameters, current vehicle parameters and predicted vehicle parameters from a plurality of alternative control variants Control variants are selected. In applications, an influence of the selected control variants and their suitability for demand-controlled control of the cruise control system are checked based on a simulation of a progression of the vehicle speed and a suitable control variant or several suitable control variants are activated and an unsuitable control variant or several unsuitable control variants are rejected. In this case, limits of the hysteresis range are additionally varied so as to increase the utilization of a kinetic energy store when driving up hills and depressions by means of a terrain forecast.

If an actual speed of the vehicle comes to the lower limit of the target speed corridor, a drive desired torque is increased by means of the speed control system in such a way that the lower limit is not or hardly undershot. If the actual speed encounters the upper limit of the target speed corridor when driving down a gradient, brake systems of the vehicle are actuated. If the vehicle is a hybrid vehicle, a drive unit designed as an electric motor can also be used for braking. However, a braking power generated by this is often insufficient in the event that the braking is activated only when the upper limit is exceeded, so that a further brake, such as a trained as a retarder retarder is activated. As a result, however, recuperation potential is not utilized, as the additional activation of the duration or service brakes destroys energy that could be recuperated.

Also from the DE 10 2008 019 174 A1 For example, a method and an apparatus for operating a first vehicle are known in which a current vehicle position, information about a present route and / or a vehicle speed is determined. Based on the information obtained, a vehicle speed is controlled and regulated. Furthermore, a predefined vehicle speed, an instantaneous drive step and a momentary drive and brake torque are controlled and controlled as a function of at least one parameter of the upcoming route and in dependence on at least one parameter of a preceding second vehicle.

Furthermore, the describes DE 10 2009 030 784 A1 a method of controlling operation of a vehicle with vehicle and engine and transmission control. Several environmental parameters, vehicle parameters, vehicle operating parameters and route parameters are recorded. For a route ahead starting at a current vehicle position, the vehicle operating conditions and the associated control parameters are determined by means of a vehicle operating cost function and stored in a buffer as optimized vehicle control parameters. The vehicle operating cost function is determined by means of an iterative numerical method, taking into account the driver prescribable restrictions and secondary conditions for the vehicle operating and the vehicle control parameters.

The object of the invention is to provide a method for operating a hybrid drive train of a vehicle that is improved over the prior art and an improved device for carrying out the method.

With regard to the method, the object is achieved by the features specified in claim 1 and in terms of the device by the features specified in claim 9.

Advantageous embodiments of the invention are the subject of the dependent claims.

In the method for operating a hybrid drive train of a vehicle comprising at least one first drive unit and a second drive unit, an operating strategy for the hybrid drive train is determined as a function of a route profile lying ahead.

According to the invention, a speed trajectory of the vehicle for the preceding route profile is predicted by means of a prediction simulation, such that a braking torque is generated at a predicted excess speed of a target speed corridor at a determined position on the route profile by means of a second drive unit of the hybrid drive train designed as an electric motor generated electrical energy is stored in an energy storage unit of the hybrid powertrain that at least the amount of crossing the target speed corridor is reduced or the crossing of the target speed corridor is avoided.

The inventive method allows in a particularly advantageous manner, a maximum generation of electrical energy in a recuperation and at the same time at least the amount of crossing the target speed corridor is reduced or exceeding the target speed corridor avoided. Also, wear of service brakes of the vehicle is reduced.

According to one embodiment of the method according to the invention, a planning of the generation of the braking torque, d. H. a determination of the braking torque to be generated, only performed when a current speed of the vehicle is within the target speed corridor. By this condition it is achieved that the determination of the required braking torque is only performed in operating situations in which this is also required. Thus, the capacity of a computing power can be saved.

In one possible embodiment of the method according to the invention, the generation of the braking torque by means of the second drive unit is carried out in a pushing operation of a first drive unit of the hybrid drive train designed as an internal combustion engine. Thus, when driving on a steep gradient, a large braking torque can be generated without having to use the vehicle's constant and service brakes to decelerate it. At the same time the recuperation is maximized.

In an alternative embodiment, the generation of the braking torque by means of the second drive unit is performed in an open state of a clutch arranged between the second drive unit and the first drive unit of the hybrid drive train designed as an internal combustion engine. Thus, even at low slope sections or short straight sections recuperation with low braking torque can be done.

Furthermore, the setting of the braking torque is carried out in particular in such a way that, as a function of a topography of the preceding route profile and / or depending on the predicted speed trajectory, an adjustment of the braking torque is performed variably such that a maximum possible amount of electrical energy is generated.

According to a further development, a predefined maximum time duration is predetermined until an upper limit of the target speed corridor is reached. Thus, the method can be carried out while increasing the recuperation such that no restriction occurs in the operation of the cruise control system.

In a possible embodiment of the method according to the invention, an additional drive torque for supporting a first drive unit designed as an internal combustion engine is generated at a predicted drop below a predeterminable target speed corridor at a determined position on the route profile by means of the second drive unit such that at least the amount of underrun of the target speed corridor is reduced or the falling below the target speed corridor is avoided. As a result, a significant gain in comfort can be achieved in the transition to operation of the drive unit designed as an internal combustion engine.

In a possible further embodiment, a planning of the generation of the additional drive torque, ie, a determination of the drive torque to be generated, is only performed if a current speed of the vehicle is within the target speed corridor. This condition ensures that the determination of the required drive torque is performed only in operating situations, in which this is necessary. Thus, the capacity of a computing power can be saved.

• – eine Ermittlungseinheit zur Ermittlung zumindest eines Vorausschauhorizonts,
• – eine mit der Ermittlungseinheit gekoppelte oder in die Ermittlungseinheit integrierte Positionserfassungseinheit zur Erfassung einer Position des Fahrzeugs,
• – eine mit der Ermittlungseinheit gekoppelte oder in die Ermittlungseinheit integrierte Speichereinheit zur Speicherung digitaler Kartendaten,
• – ein mit der Ermittlungseinheit gekoppeltes oder in die Ermittlungseinheit integriertes Berechnungsmodul zur Berechnung des zumindest einen Vorausschauhorizonts anhand der Position des Fahrzeugs und dem zumindest aus den digitalen Kartendaten ermittelten Streckenprofil,
• – ein Betriebsstrategiemodul zur Ermittlung und Zurverfügungstellung der Betriebsstrategie,
• – eine erste Steuereinheit zur Steuerung des Antriebstrangs des Fahrzeugs mit einer Geschwindigkeitsregelfunktion, einer Gangermittlungsfunktion zur automatischen Gangvorgabe und einem Momentenaufteilungs- und -verwaltungsmodul zur Vorgabe von Antriebsmomenten und/oder Bremsmomenten an zumindest eine Antriebseinheit des Fahrzeugs und an Dauer- und Betriebsbremsen und/oder
• – eine zweite Steuereinheit zur Steuerung zumindest einer Energiespeichereinheit des Fahrzeugs.

For efficient and reliable implementation of the method according to the invention, the device according to the invention comprises

• A determination unit for determining at least one look-ahead horizon,
• A position detection unit coupled to the determination unit or integrated into the determination unit for detecting a position of the vehicle,
• A memory unit coupled to the determination unit or integrated into the determination unit for storing digital map data,
• A calculation module coupled to the determination unit or integrated into the determination unit for calculating the at least one look-ahead horizon based on the position of the vehicle and the route profile determined at least from the digital map data,
• An operating strategy module for identifying and providing the operating strategy,
• A first control unit for controlling the drive train of the vehicle with a speed control function, a gear determination function for automatic gear specification and a torque distribution and management module for specifying drive torque and / or braking torque to at least one drive unit of the vehicle and to continuous and service brakes and / or
• - A second control unit for controlling at least one energy storage unit of the vehicle.

Embodiments of the invention are explained in more detail below with reference to drawings.

Showing:

1 1 schematically shows a sequence of a method according to the invention for operating a hybrid drive train of a vehicle,

2 schematically different speed trajectories and a target speed corridor and

3 schematically a block diagram of an overall system of a vehicle and a device for operating a vehicle designed as a hybrid vehicle.

Corresponding parts are provided in all figures with the same reference numerals.

In 1 is a sequence of a method according to the invention for operating a in 3 closer illustrated vehicle 1 with a hybrid powertrain 2 shown.

The hybrid powertrain 2 includes a trained as an internal combustion engine first drive unit 2.1 and a second drive unit designed as an electric motor 2.2 , The first and second drive unit 2.1 . 2.2 are doing by means of a clutch 2.3 Coupled with each other.

For operation of the second drive unit 2.2 this is with an energy storage unit 2.4 , For example, a high-voltage battery coupled, which is at least chargeable by recuperation.

Furthermore, the hybrid powertrain includes 2 a gearbox 2.5 , An example trained as a retarder retarder 2.6 and a service brake designed in particular as a wheel brake 2.7 ,

Cruise control systems known from the prior art for vehicles 1 , in particular for heavy commercial vehicles, have a dead zone, which is formed by a desired value of the predetermined speed v and it is also a in 2 Target speed corridor ZK, a speed hysteresis or a hysteresis range of the target speed known. Is there an actual speed of the vehicle 1 in the target speed corridor ZK, a control activity of the cruise control system is prevented and only when one of the in 2 Boundaries HG1, HG2 of the hysteresis range or target speed corridor ZK are resumed.

The hysteresis range serves on the one hand to debounce a so-called train-thrust changeover, but is also used with a larger range of values, in particular for an upper limit HG2, as a fuel saving measure, in order to enable a "swing recovery" in the downhill.

If such a cruise control system is combined with a hybrid drive and an associated controller, HG2 is usually used at the upper limit, preferably by means of the second drive unit designed as an electric motor 2.2 an electric braking torque in addition to other braking systems of the vehicle 1 activated. As a result, however, it may happen that exceeding the upper limit HG2 only by activation of the permanent and / or service brakes 2.6 . 2.7 can be prevented, which disadvantageously existing Rekuperationspotenzial is not used.

For this reason, the method according to the invention provides that the second drive unit designed as an electric motor 2.2 generated electrical braking torque depending on the respective conditions already clearly before reaching the upper limit HG2 is generated.

This is done in a first step 51 in a forecast simulation a future speed trajectory vT predicts which vehicle 1 on the one ahead, in 2 will have more detailed route profile SP.

The information about the preceding route profile SP are based on generally known devices and methods, such as based on data from a navigation device, position data of a satellite-based navigation device, using general route information, based on information on signs and road signs, based on camera data, a vehicle to Vehicle communication, a vehicle-to-infrastructure communication and / or other devices and methods determined.

In a second method step S2, it is checked whether there is a current speed v of the vehicle 1 within the target speed corridor ZK.

If this is the case, it is determined in a third method step S3 whether the future velocity trajectory vT determined in the first method step S1 is determined by means of the method described in FIG 3 detailed automatic cruise control system 3.3.1 predetermined target speed corridor ZK exceeds a determined position on the route profile SP. This can occur, for example, when driving on a slope.

If this is the case, it is determined in a fourth method step S4, at which position on the route profile SP a generation of a braking torque by the second drive unit 2.2 of the hybrid powertrain 2 is possible such that an energy gain in the generation of the braking torque for recuperation of the energy storage unit 2.4 maximized while avoiding the crossing of the target speed corridor ZK is avoided.

Subsequently, a corresponding control of the hybrid drive train takes place at the position determined on the route profile SP 2 in such a way that reaching the upper limit HG2 of the target speed corridor ZK is postponed, but not necessarily prevented, as late as possible.

This can advantageously already happen at the reversal point of the velocity trajectory vT when entering the gradient. As a result, the speed trajectory vT of the vehicle runs somewhat flatter and the braking demand when passing through the upper limit HG2 is lower and may optionally continue to be alone with that by means of the second drive unit 2.2 generated braking torque and thus used for recuperation. This is exemplary in 2 shown in more detail.

In this case, depending on a topography of the route profile SP and depending on the predicted speed trajectory vT, the setting of the braking torque is carried out variably such that a maximum possible amount of electrical energy is generated, with a predefined maximum time not exceeding an upper limit of the target speed corridor becomes. This is by appropriate control of the second drive unit 2.2 , the clutch 2.3 and the other components of the hybrid powertrain 2 easy and effective to carry out.

It is particularly advantageous here, depending on a strength of the gradient between the first and second drive unit 2.1 . 2.2 located clutch 2.3 to open, so the engine drag torque of the first drive unit 2.1 to eliminate, provided that thus generated additional momentum due to the open hybrid powertrain 2 can be used meaningfully.

For steep slope sections, the generation of the braking torque by means of the second drive unit 2.2 but also in a pushing operation of the first drive unit 2.1 with the clutch closed 2.3 done so that a use time and consequent wear of the service and service brakes 2.6 . 2.7 be minimized.

If the predicted speed trajectory vT does not show an increase beyond the upper limit HG2 of the target speed corridor ZK, no braking torque is generated by means of the second drive unit 2.2 generated, as this would lead to an unnecessary deceleration with a required subsequent re-acceleration by means of drive power. This shows the special advantages of the advance simulation of the route profile SP.

By applying the subject invention is in heavy commercial vehicles with a hybrid powertrain 2 a significant increase in the recuperation potential of more than 30% achievable.

Furthermore, the method according to the invention is used in such a way that in the case of a forecasted undershooting of the device by means of the automatic cruise control system 3.3.1 predetermined target speed corridor ZK and, if the current speed v of the vehicle 1 is located within the target speed corridor ZK, at a determined position on the route profile SP by means of the second drive unit 2.2 such an additional drive torque to support the trained as an internal combustion engine first drive unit 2.1 is generated that the falling below the target speed corridor ZK is avoided. As a result, a gain in comfort in the transition to the operation with internal combustion engine can be achieved.

2 schematically shows different speed trajectories vT1, vT2 and a target speed corridor ZK with a lower limit HG1 and an upper limit HG2 and the vehicle 1 when driving on a route profile SP. The speed trajectories vT1, vT2 and the target speed corridor ZK with its limit HG1, HG2 are in this case as the course of the speed v of the vehicle 1 shown as a function of time.

In the illustrated embodiment, the vehicle 1 first ride a slight slope, using the cruise control system 3.3.1 the speed v of the vehicle 1 was set to a minimum speed v _min at the lower limit HG1 in order to be able to use the entire hysteresis range in the following gradient and the then occurring thrust phase.

Upon reaching the top, the braking torque by means of the second drive unit by means of the method according to the invention 2.2 generated, so that compared to a ride on the slope without generating the braking torque, as the first speed trajectory vT1 shows a longer Rekuperationsphase R is feasible, since the second speed trajectory vT2 a maximum speed v _max at the upper limit HG2 of the target speed corridor ZK only to reached later. This is an additional, for example by means of the retarder 2.6 can be reduced generating braking torque while maximizing recuperation.

In 3 is an overall system GS from the vehicle designed as a hybrid vehicle 1 and a device 3 for the operation of the vehicle 1 shown.

The device 3 includes a determination unit 3.1 for determining at least one look-ahead horizon, wherein the determination unit 3.1 in a manner not shown, a position detection unit for detecting a position of the vehicle 1 , for example based on GPS data, and storage unit for storing digital map data. Furthermore, a calculation module for calculating the at least one look-ahead horizon based on the position of the vehicle is likewise not shown in any more detail 1 and the route profile SP determined from the digital map data. The at least one look-ahead horizon encompasses a gradient or curvature profile over the selected horizon length.

Furthermore, the device comprises 3 an operating strategy module 3.2 , by means of which the respective operating strategy for the vehicle 1 determined and made available. The operating strategy module 3.2 in turn comprises means for generating the predictive hybrid operating strategy.

This hybrid operating strategy is taken from the operating strategy module 3.2 to a first control unit 03.03 , which is also referred to as a central powertrain control module, which is used to control the hybrid powertrain 2 is provided and this, the cruise control system 3.3.1 , also referred to as speed control module, for performing the speed control function, a shift strategy module 3.3.2 for performing a gait determination function for automatic gait specification and a torque distribution and management module 3.3.3 includes.

By means of the cruise control system 3.3.1 the setpoint speed predetermined by the driver is regulated, influenced via the changeable blur range via the predictive driving strategy, and a total required drive and / or braking torque is determined.

By means of the switching strategy module 3.3.2 becomes an optimal gear of the transmission 2.5 adjusted, wherein the switching strategy module 3.3.2 possibly influenced by the forward-looking operating strategy. The from the shift strategy module 3.3.2 determined gear is to a transmission electronics 3.4 transmitted.

By means of the torque sharing and management module 3.3.3 From the specifications of all control functions, the setpoint torques for the first drive unit 2.1 , the second drive unit 2.2 , the duration and service brakes 2.6 . 2.7 determined, wherein a torque distribution between the first and second drive unit 2.1 . 2.2 from the predictive hybrid operating strategy of the first control unit 03.03 being affected.

Furthermore, the device comprises 3 a second control unit 3.5 for controlling the energy storage unit 2.4 wherein the second control unit 3.5 in a manner not shown comprises a monitoring module, which the loading and loading state of the energy storage unit 2.4 recorded and this to the first control unit 03.03 reports.

Furthermore, the device comprises 3 an engine electronics 3.6 the first drive unit 2.1 , a control electronics 3.7 for the second drive unit 2.2 , the transmission electronics 3.4 , a continuous brake electronic 3.8 for controlling the endurance brakes 2.6 , For example, a retarder, and a service brake electronics 3.9 for controlling the service brakes 2.7 of the vehicle 1 , These components come with the first control unit 03.03 are coupled and dependent on the operating strategy of the vehicle determined for the forecast horizons 1 operated and controlled.

LIST OF REFERENCE NUMBERS

1

vehicle

2

Hybrid powertrain

2.1

first drive unit

2.2

second drive unit

2.3

clutch

2.4

Energy storage unit

2.5

transmission

2.6

Mountain brake

2.7

service brake

3

contraption

3.1

determining unit

3.2

Operating strategy module

3.3

first control unit

3.3.1

Cruise control

3.3.2

Shift strategy module

3.3.3

Moment sharing and management module

3.4

transmission electronics

3.5

second control unit

3.6

engine electronics

3.7

control electronics

3.8

Continuous braking electronics

3.9

Service brake electronics

GS

overall system

HG1, HG2

border

R

recuperation

S1 to S4

step

SP

route profile

v

speed

V _max

maximum speed

_min

minimum speed

vT, vT1, vT2

Geschwindigkeitstrajektorie

ZK

Target speed corridor

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 102009040682 A1 [0004]
• DE 102008019174 A1 [0006]
• DE 102009030784 A1 [0007]

Claims (9)

Method for operating at least one first drive unit ( 2.1 ) and a second drive unit ( 2.2 ) hybrid powertrain ( 2 ) of a vehicle ( 1 ), wherein an operating strategy for the hybrid powertrain (FIG. 2 ), characterized in that by means of a lookahead simulation a speed trajectory (vT, vT1, vT2) of the vehicle ( 1 ) is predicted for the preceding route profile (SP), whereby in the case of a predicted exceedance of one by means of an automatic cruise control system (SP) 3.3.1 ) predetermined target speed corridor (ZK) at a determined position on the route profile (SP) by means of the designed as an electric motor second drive unit ( 2.2 ) of the hybrid powertrain ( 2 ) generates such a braking torque and a generated electrical energy in an energy storage unit ( 2.4 ) of the hybrid powertrain ( 2 ) that at least the amount of crossing of the target speed corridor (ZK) is reduced or the crossing of the target speed corridor (ZK) is avoided. A method according to claim 1, characterized in that a planning of the generation of the braking torque is carried out only when a current speed (v) of the vehicle ( 1 ) is within the target speed corridor (ZK). A method according to claim 1 or 2, characterized in that the generation of the braking torque by means of the second drive unit ( 2.2 ) in a pushing operation of the internal combustion engine designed as a first drive unit ( 2.1 ) of the hybrid powertrain ( 2 ) is carried out. A method according to claim 1 or 2, characterized in that the generation of the braking torque by means of the second drive unit ( 2.2 ) in an opened state between the second drive unit ( 2.2 ) and designed as an internal combustion engine first drive unit ( 2.1 ) of the hybrid powertrain ( 2 ) arranged coupling ( 2.3 ) is carried out. Method according to one of the preceding claims, characterized in that depending on a topography of the preceding route profile (SP) and / or in dependence of the predicted speed trajectory (vT, vT1, vT2) an adjustment of the braking torque is carried out variably such that a maximum possible amount electrical energy is generated. Method according to one of the preceding claims, characterized in that a predefined maximum time until reaching an upper limit (HG2) of the target speed corridor (ZK) is specified. Method according to one of the preceding claims, characterized in that, in the case of a predicted undershooting of an automatic speed control system ( 3.3.1 ) predetermined target speed corridor (ZK) at a determined position on the route profile (SP) by means of the second drive unit ( 2.2 ) Such an additional drive torque to support a trained as an internal combustion engine first drive unit ( 2.1 ) is generated, that at least the amount of falling below the target speed corridor (ZK) is reduced or the falling below the target speed corridor (ZK) is avoided. A method according to claim 1, characterized in that a planning of the generation of the additional drive torque is only performed when a current speed (v) of the vehicle ( 1 ) is within the target speed corridor (ZK). Contraption ( 3 ) for performing a method according to one of claims 1 to 8, comprising - a determination unit ( 3.1 ) for determining at least one look-ahead horizon, - one with the determination unit ( 3.1 ) or integrated into the determination unit position detecting unit for detecting a position of the vehicle ( 1 ), - one with the determination unit ( 3.1 ) or in the investigation unit ( 3.1 ) integrated memory unit for storing digital map data, - one with the determination unit ( 3.1 ) or in the determination unit ( 3.1 ) integrated calculation module for calculating the at least one look-ahead horizon based on the position of the vehicle ( 1 ) and the route profile (SP) determined at least from the digital map data, - an operating strategy module ( 3.2 ) for the identification and provision of the operating strategy, - a first control unit ( 03.03 ) for controlling the hybrid powertrain ( 2 ) of the vehicle ( 1 ) with a cruise control system ( 3.3.1 ), a shift strategy module ( 3.3.2 ) for automatic gear specification and a torque distribution and management module ( 3.3.3 ) for specifying drive torques and / or braking torques to at least one drive unit ( 2.1 . 2.2 ) of the vehicle ( 1 ) and permanent and service brakes ( 2.6 . 2.7 ) and / or - a second control unit ( 3.5 ) for controlling at least one energy storage unit ( 2.4 ) of the vehicle ( 1 ).

Images