DE102019004368A1 - Method and device for controlling a vehicle speed - Google Patents

Abstract

The invention relates to a method, carried out by a control device (50) of a vehicle (1), for controlling such that the vehicle reaches a set speed, the method being designed to be carried out when the vehicle (1) is traveling on a road one or more road sections (RSD) with a downward slope, followed by a curve section (RSC) of the road, the vehicle (1) having an automatic or semi-automatic transmission and the method comprising the following steps: - determining (s101) a target setting speed v for the Vehicle (1) at a predetermined location (x) in front of the curve section (RSC) of the road based on at least the radius of the curve section of the road and the weight of the vehicle (1), - selecting (s102) a gear for decelerating the vehicle speed towards the target setting speed of the predetermined location (x), the gear being selected based on s at least the weight of the vehicle, the current speed of the vehicle and the height difference between the current position of the vehicle and the curve section (RSC) of the road, and - controlling (s103) the transmission to engage the selected gear.

Description

TECHNICAL AREA

The invention relates to a method carried out by a control device of a vehicle for controlling such that the vehicle reaches a set speed, as defined in the appended claims. The invention also relates to a control device which is set up to control such that the vehicle reaches the set speed, and a vehicle with the control device as defined in the appended claims. The invention further relates to a computer program and a computer-readable medium as defined in the appended claims.

THE PRIOR ART

An automatic speed control system (the term “control” in this application particularly includes a “control”), also referred to as a speed control system, is a system for adjusting the speed of a motor vehicle, which is a passenger car or a heavy-duty vehicle, e.g. a truck or bus. Simple automatic speed control systems are set up to maintain a desired set speed for the vehicle by increasing or decreasing the power applied by the engine. The automatic speed control system can be activated / deactivated and operated by means of an operating device and / or an interface which can be arranged near the steering wheel of the vehicle. An activated automatic speed control system is usually deactivated by the driver when the driver presses the brake pedal or a clutch pedal.

Controlling trucks on long, downhill roads with many bends, such as mountain roads, can be very challenging for the driver. In order to adapt the speed of the vehicle to faster traffic, the vehicle is often driven downhill at higher speeds on straight sections, while driving at very low speeds in curves. This often complicates the use of the vehicle's cruise control system, which is specially designed for downhill speed control (DHSC), although the driver will eventually apply the brakes instead. Brakes based on friction, such as drum brakes or disc brakes, can be worn out faster, which means more frequent service intervals. It is therefore desirable to reduce the need to use wheel brakes based on friction.

The US 2017 / 0159805A1 describes a predictive transmission control of a vehicle, which takes into account the course of the road. But also in view of existing systems, there is still a need to improve the control of a vehicle which is traveling on a road with one or more road sections with a downhill course followed by a curve.

BRIEF DESCRIPTION OF THE INVENTION

In recent years, automatic speed control systems have been developed to reduce the need for personal intervention by the driver or operator of the vehicle. However, there is still a need for improvement with regard to the control systems of the vehicle, in particular for driving the vehicle on a road with one or more road sections leading downhill, followed by a road curve. In particular, there is a need for the driver to be efficiently assisted on roads with downhill sections followed by a curve, with no disadvantages in terms of driver, vehicle and traffic safety.

It is an object of the invention to provide a method and a control device for controlling the speed of a vehicle on a road with one or more downhill road sections before a curve section such that so-called manual interventions by the driver or the operator of the vehicle are minimized or eliminated entirely , the vehicle speed being controlled in a safe manner. The term “taxes” in this application and in the claims also includes “rules”. The term “manual” encompasses every physical intervention on the part of the driver or operator of the vehicle, in particular also with the foot.

A further object of the invention is to reduce the use of wheel brakes based on friction and thus to reduce the need for maintenance and repair work.

• - Bestimmen einer Zieleinstellgeschwindigkeit V_target für das Fahrzeug an einem vorab bestimmten Ort vor der Straßenkurve auf Basis von zumindest dem Radius der Straßenkurve und dem Gewicht des Fahrzeuges,
• - Auswählen eines Ganges zum verlangsamen der Fahrzeuggeschwindigkeit in Richtung auf die Zieleinstellgeschwindigkeit V_target an dem vorab bestimmten Ort vor der Straßenkurve, wobei der Gang ausgewählt wird auf Basis von zumindest dem Gewicht des Fahrzeuges, einer momentanen Geschwindigkeit des Fahrzeuges und einer Höhendifferenz zwischen der momentanen Position des Fahrzeuges und der Straßenkurve, und
• - Steuern des Getriebes zum Einlegen des ausgewählten Ganges.

The above objects are achieved by a method according to the appended claims. The method is carried out by a control device of a vehicle for controlling such that a set speed is reached, the method being adapted to be carried out when driving on a road with one or more downhill road sections which are followed by a road curve. The vehicle has an automatic or semi-automatic transmission. The process includes the following steps:

• - Determining a _target setting speed V _target for the vehicle at a predetermined location in front of the road curve based on at least the radius of the road curve and the weight of the vehicle,
• Selecting a gear to slow the vehicle speed toward the _{target set} speed V _target at the predetermined location before the road curve, the gear being selected based on at least the weight of the vehicle, a current speed of the vehicle and a height difference between the current position the vehicle and the road curve, and
• - Control the gearbox to engage the selected gear.

By determining a target speed in front of the road curve at a predetermined location and by selecting a gear to slow the vehicle in the direction of the target speed, the need for manual use of the vehicle brakes is reduced.

In general, a vehicle takes a higher speed on sections of road with a downhill slope. Thus, the vehicle can roll at least partially downhill on such road sections, thereby promoting economical operation of the vehicle. Due to the braking torque due to the gear selection, the speed of the vehicle can be reduced while reducing the wear on brakes based on friction and thus the economy of the journey can be further improved.

The step of determining the target speed v _target may include a calculation taking into account a predetermined maximum lateral acceleration of the vehicle, optionally the inclination of the curved road section and optionally a given speed limit. This further improves security and reduces the risk of speeding. The speed limit can be taken into account as it is often higher than the maximum speed that is permitted due to the lateral acceleration of the vehicle. However, if the speed limit is lower than the speed permitted due to the lateral acceleration of the vehicle, it must be taken into account.

The step of selecting a gear can also be based on the kinetic energy which is given by the inclination of the downhill road section (RSD) and on the basis of a predetermined braking distance (braking distance). By selecting a short braking distance, it is possible to increase the average speed for the vehicle. Therefore, in some exemplary embodiments, the predetermined braking distance can be selected as the shortest possible and / or that for reaching the target setting speed v _target required time can be chosen as short as possible. On the other hand, if the braking distance is longer than the shortest possible, gentler braking can be achieved and thus better comfort for the driver.

In addition to the deceleration torque based on the gear selection, the method can also include the calculation of an additional deceleration torque that is required to reach the target speed v _target , in addition to the deceleration torque due to the gear selection step. This can further improve vehicle safety.

An additional deceleration torque can be generated by an auxiliary brake, such as a retarder (permanent brake) and / or an electric brake and / or by setting a compression release motor brake and / or an exhaust brake. By using such an auxiliary brake or by adjusting a compression release motor brake and / or an exhaust brake, the use of friction-based wheel brakes can be reserved for more extreme braking situations.

In the method, the selection of the predetermined location can be based on map data. The accuracy of the method can be improved by using map data.

The step of selecting the gear can take into account gear data obtained by simulating the deceleration of the vehicle with different gears, wherein at least the weight of the vehicle, the braking distance and the inclination of the road are variables which are taken into account in the simulation. By using simulation data, the road properties on the planned route and vehicle data can be taken into account and thus a better adapted control of the vehicle can be achieved. The target speed and / or the braking distance can thus be determined in advance, the need for a calculation during operation of the vehicle being eliminated or at least reduced.

To improve the safety of the vehicle, friction-based wheel brakes can also be used to reduce the target speed v _target to reach.

The invention also relates to a computer program which has a program code for causing a control device or a computer connected to a control device to carry out the steps explained above.

Furthermore, the invention relates to a computer-readable medium with a program code stored therein for executing the method steps described above when the computer program runs on a control device or a computer connected to a control device.

The objectives and advantages described above in connection with the method are thus also achieved by the corresponding control device according to the claims and the description below.

• - Bestimmen einer Zieleinstellgeschwindigkeit v_target für das Fahrzeug an einem vorab bestimmten Ort vor der Straßenkurve auf Basis von zumindest einem Radius des Kurvenabschnittes der Straße und einem Gewicht des Fahrzeuges,
• - Auswählen eines Ganges zum Verzögern der Fahrzeuggeschwindigkeit in Richtung auf die Zieleinstellgeschwindigkeit v_target an dem vorab bestimmten Ort vor der Straßenkurve, wobei der Gang ausgewählt wird unter Berücksichtigung von zumindest dem Gewicht des Fahrzeuges, einer momentanen Geschwindigkeit des Fahrzeuges und einer Höhendifferenz zwischen der momentanen Position des Fahrzeuges und dem Kurvenabschnitt der Straße, und
• - Steuern des Getriebes zum Einlegen des ausgewählten Ganges.

The control device is set up to control such that the vehicle reaches a set speed, the vehicle being set up to travel on a road with one or more downhill road sections followed by a curve section of the road, the vehicle having an automatic or semi-automatic transmission , The control unit is set up to:

• - Determine a target setting speed v _target for the vehicle at a predetermined location in front of the road curve based on at least a radius of the curve section of the road and a weight of the vehicle,
• - Select a gear to decelerate the vehicle speed toward the target set speed v _target at the predetermined location before the road curve, the gear being selected taking into account at least the weight of the vehicle, a current speed of the vehicle and a height difference between the current position of the vehicle and the corner portion of the road, and
• - Control the gearbox to engage the selected gear.

The target speed v _target can be calculated based on a predetermined maximum vehicle lateral acceleration and optionally the inclination of the winding road section and optionally the current speed limit.

The control device can be set up to select a gear on the basis of the kinetic energy given by the inclination of the downhill road section and a predetermined braking distance. The predetermined braking distance may be the shortest possible distance and / or take into account a time required to reach the target setting speed v _target ,

The control device can be set up to calculate an additional braking torque that is required to reach the target speed v _target , The control device can be set up to activate an auxiliary brake, which can be a retarder and / or an electric brake if an additional braking torque is required, and / or for setting a compression release motor brake and / or an exhaust gas brake to increase the braking torque.

The predetermined location can be selected based on map data.

The control device can be set up to select the gear on the basis of transmission data which are obtained by simulating decelerations of the vehicle with different gears, the weight of the vehicle, the braking distance and the inclination of the road being taken into account in the simulation.

The control device may be configured to perform or request the use of friction-based wheel brakes at the target speed v _target to reach.

The invention also relates to a vehicle which has a control device or the computer-readable medium as described above.

Further objects, features and advantages of the invention will become apparent from the following detailed description.

list of figures

• 1 zeigt schematisch ein Fahrzeug mit einer Steuervorrichtung gemäß der vorliegenden Beschreibung;
• 2 zeigt schematisch einen Teil des Antriebsstranges des Fahrzeuges gemäß 1;
• 3 zeigt schematisch einen Straßenabschnitt RS mit bergab gerichteter Neigung;
• 4 zeigt schematisch ein Fahrzeug gemäß 1, welches auf einer Straße fährt mit einem oder mehreren Abschnitten mit Bergabneigung, gefolgt von einem Kurvenabschnitt der Straße;
• 5 zeigt ein schematisches Flussdiagramm für ein Verfahren zum Steuern derart, dass das Fahrzeug eine eingestellte Geschwindigkeit erreicht, gemäß einem Ausführungsbeispiel; und
• 6 erläutert schematisch eine Steuervorrichtung gemäß einem Ausführungsbeispiel.

For a deeper understanding of the invention and further objects and advantages thereof, the following description of details with reference to the figures is recommended, in which the same reference numerals are assigned to corresponding components:

• 1 schematically shows a vehicle with a control device according to the present description;
• 2 shows schematically a part of the drive train of the vehicle according to 1 ;
• 3 schematically shows a road section RS with downward slope;
• 4 schematically shows a vehicle according to 1 driving on a road with a one or more sections with a downward slope, followed by a curve section of the road;
• 5 shows a schematic flow diagram for a method for controlling such that the vehicle reaches a set speed, according to an embodiment; and
• 6 explains schematically a control device according to an embodiment.

DESCRIPTION OF DETAILS

If heavy-duty vehicles, such as lorries, drive on downhill roads with several curve sections, there is a need to adjust the speed of the vehicle according to the changing curves.

The speed is typically adjusted to be low in corner sections of the road and higher in the downhill sections of the road, especially when the downhill sections are substantially straight so as to adapt the vehicle speed to faster traffic on the road how the traffic of passenger cars. This can result in a large number of drivers applying the brakes manually (in the broadest sense including foot brakes, of course) to adjust the braking torque, as this is generally considered to be an easier maneuver than adjusting the adjustable speed of an automatic cruise control system Vehicle, such as the so-called downhill speed control (DHSC) of the vehicle. Therefore, it is an object of the present description to teach a method and a control device for controlling the speed of the vehicle so that manual intervention by the driver or operator of the vehicle is minimized or becomes unnecessary by controlling the vehicle speed in a safe manner. It is also a goal to reduce the use of wheel brake based on friction and thus reduce the need for maintenance and repair work related to such brakes.

1 shows schematically a side view of a heavy duty vehicle 1 , in this case a truck, with a drive unit 2 , which can be an internal combustion engine. In the context of the present description, the vehicle need not be a truck, it could be any other type of heavy-duty vehicle, such as a bus. The vehicle 1 still has a gearbox 6 which with the driving wheels 8th of the vehicle 1 connected is. The vehicle can also be a hybrid vehicle with a drive unit including an electric motor (not shown) for generating propulsive force for the vehicle, in addition to the internal combustion engine 2 , Wheel brakes based on friction are connected to the wheels of the vehicle (not shown).

2 shows schematically parts of the drive train of the vehicle 1 , The drive train contains the drive unit 2 which, in the present case, mechanically via a clutch 4 through a shaft with a first side of a gearbox 6 connected is. The second side of the transmission 6 is mechanical via a drive shaft 5 with a differential 3 connected, which interacts with the drive axle. The drive axle has left and right drive shafts 7 which the drive wheels 8th rotate.

With this well-known arrangement, the mechanical performance of the drive unit 2 through a number of transmission facilities, such as the clutch 4 , The gear 6 , the drive shaft 5 , the differential 3 and the drive shafts 7 on the drive wheels 8th to propel the vehicle 1 transfer. The gear 6 is a transmission device with a number of gears for driving forward to propel the vehicle 1 , and usually also with one or more reverse gears. The number of forward gears varies, but twelve forward gears are common in trucks, for example.

The transmission ratio of the drive train can vary in order to assume different values (ie arrangements with different transmission ratios are generated). The different gear ratios depend, among other things, on the one currently in the transmission 6 gear engaged and the ratio of the differential 3 , The powertrain can take on several different discrete gear ratios and / or take on a continuous range of ratios; with the gearbox 6 it can be, for example, an automatic transmission with so-called converters or another type of transmission with continuously variable transmission. The vehicle of the present description has automatic or semi-automatic transmission and therefore can take a number of different discrete gear ratios and / or can take a continuous range of ratios.

Furthermore, the vehicle points 1 on or is connected to a control device 50 with one or more electronic control units (ECU). The task of the mentioned control device is the control of one of several functions of the vehicle 1 , eg the speed, with one or more actuators, which relate to the different functions of the vehicle 1 relate, such as an engine control, gear change, speed control, suspension, etc. The control device 50 can use a number of different parameters, for example the current engine speed, the current position of the accelerator pedal, the current engine torque, data from various sensors and map data for controlling the various functions of the vehicle 1 ,

According to the present description, the control device is configured to control such that the vehicle reaches a set speed when driving on a road with one or more road sections with a downhill gradient, followed by a curve section of the road. The set speed is reached at a predetermined position in front of the curve section of the road, e.g. at the end of the downhill sloping road section at the entrance to the curve section of the road with the previous road section sloping downhill.

The downhill road sections generally have an incline that is determined by a difference in height between two points on the road. In one example, which is only for the purpose of explanation and not for delimitation, the road can have a height difference from a highest point to a lowest point of the road from approximately 30 m to 3000 meters, as examples. The length of the road may vary, and may have one or more road sections with a slope, followed by a curve section of the road. The road may have several, such as 2 to 100 or more, road sections with downward slope followed by a curve section of the road, each by way of example.

The controller and / or method may be activated to operate in accordance with the method described herein or an embodiment thereof over a specified length of road with one or more downhill road sections followed by a curve portion of the road. For example, the specified street length can be 50 m or more, e.g. up to 300 km or more, without limitation to such lengths. The control device can have a device for activating the method at the start of the road and the method can be deactivated at the end of the road. For example, the control system can be configured to execute the method and thus to select a driving mode according to the present description, i.e. to steer the vehicle so that it reaches a set speed when the vehicle has reached a certain point on the route. On the other hand, the operator of the vehicle can also activate the drive mode manually. This has advantages in that the mode can only be selected on certain roads.

The downhill inclined road sections can have a certain height difference, which determine a certain inclination or angle, or can have different lengths. The respective inclination can be expressed in different ways. For example, the slope can be expressed as a ratio or gradient of the climb with respect to the corresponding trip length, as a slope in percent or as a slope in degrees, each of which indicates a relationship between the length and the height difference of the respective downhill section.

To explain the height difference and slope of a road section RS with a downward slope, reference is made to 3 , RS means a section of road with a downward slope. The rise R, ie the height difference, is indicated by the vertical side of a right-angled triangle and the travel distance C is represented by the horizontal side of the triangle.

• - Der sich ergebende Neigungsgradient ist 3:36, d.h. 1:12.
• - In Prozenten beträgt die Neigung 3/36*100%=8,3%.
• - Der Winkel der Neigung kann berechnet werden aus der Gleichung θ = 3/36;

wobei θ = tan^-1(3/36) = 4,76°. Somit beträgt der Neigungswinkel 4,76°.As a numerical example, a height difference of R = 3m and a distance C on the road of C = 36m can be measured. The inclination can then be expressed in different ways as follows:

• - The resulting slope gradient is 3:36, ie 1:12.
• - The percentage is 3/36 * 100% = 8.3%.
• - The angle of inclination can be calculated from the equation θ = 3/36;

where θ = tan ^-1 (3/36) = 4.76 °. The angle of inclination is therefore 4.76 °.

The angle of the road section RS with a downward slope is therefore greater than 0 degrees.

As mentioned above, the at least one downhill road section is followed by a curve section of the road. Each curve section has a certain radius of curvature (curve radius). The radius of curvature can be obtained from map data and / or it can also be obtained by means of a sensor device, e.g. a gyro sensor, devices using the earth's magnetic field and / or a camera that provides image data relating to the road ahead of the vehicle.

The downhill road section can be a substantially straight road section or it can be a small one Have curvature, however, the curve radius corresponds to a road curvature that is smaller than the curvature of the curve section of the road that follows the road section with a downward slope. The radius of curvature of the section of road with a downward slope can be such that the road runs straight. If there is a slight curvature (curve), the radius of curvature can be, for example, 5-10 times larger than the radius of curvature of the curve section of the road, which also follows the road section with a downward slope, without being restricted to such values. The length of the curve portion of the road may be shorter than the length of the downward slope road portion and may, for example, be 5-10 times shorter than the length of the previous downward slope portion, without limitation to these values. The curve portion of the road may have a downward slope and the slope of the curve portion of the road may determine a limit on the maximum speed of the vehicle in the curve. The downward slope of the curve section can be smaller than the slope of the previous road section with a downward slope.

The data relating to the inclination and the radii of curvature can be obtained directly from map data which contain topographical data. On the other hand or in addition, data relating to the inclination and the radii of curvature can be data obtained with the control device during a previous operation of the vehicle or another vehicle on the road in this route. The control device can also be set up to calculate the inclination on the basis of map data which provide information relating to the climb, the travel distance, the bridged horizontal distance and the travel route. As mentioned above, specific sensors can be used which are designed to detect the shape of the road in front of the vehicle. The map data can be provided by any known device, for example with a global positioning system (GPS) or a corresponding device. The GPS can provide high resolution map data and can be configured to communicate with one or more satellites via radio signals.

In one embodiment, the road having one or more downward slope (RSD) sections followed by a curved section of the street is a mountain road. A mountain road is a road that runs on one side of a mountain or a road that goes up and over a mountain.

4 schematically explains an example of the type of a road with a plurality of road sections with a downward slope, such a section being designated RSD. The road shown is a mountain road. A section RSC follows a section RSD running downhill. For the sake of clarity of illustration, only such a road section is provided with a reference symbol. 4 shows a vehicle 1 on a section of road with downward slope RSD. The vehicle 1 has an automatic or semi-automatic transmission. The control device of the vehicle is set up to control the speed of the vehicle. In the context of the present description, the control device is set up, a target setting speed v _target to determine for the vehicle at a predetermined location. The target set speed may be predetermined and the control system may be configured to use this predetermined speed when determining the speed. The predetermined location is before the RSC section of the road and is localized to the end or after the RSD road section with a downward slope. In 4 the place is represented with X ₁ and it lies on the downhill road section before the vehicle enters the RSC corner section of the road. The predetermined location X ₁ can be selected based on map data or previously saved route data, being selected such that v _target is reached or is approximated at a location that ensures a safe drive through the RSC curve section of the road. The surrounding traffic on the street is thus minimally impaired, which is why the aim should be that the place X ₁ for speed v _target is chosen as near the end of the downhill road section and near the start of the RSC corner section of the road, as close as possible.

The target setting speed v _target for the vehicle is determined based on at least the radius of curvature of the curve section RSC of the road, a current speed of the vehicle and the weight of the vehicle. The target speed v _target can be calculated so that the maximum speed of the vehicle is reached before entering the curve without risk of the vehicle tipping over. As explained above, the radius can be obtained from map data. The map data including topographical data or parts thereof, from which the inclination data result, can be stored in the control device of the vehicle. This data can be used in setting the target setting speed v _target , The target setting speed can already be set for the vehicle when the route is being planned, the speed of the vehicle being determined in advance on certain road sections at the start of the route. An adjustment of the speed can become necessary during the trip, for example in accordance with the traffic conditions or the weather conditions, and the control device can be set up to adapt the previously determined speed on the basis of the current traffic situation and / or the weather data. The target speed v _target can be determined using any known technique and can be calculated based on a predetermined maximum lateral acceleration of the vehicle, optionally the slope of the corner portion of the road and optionally based on the current speed limit. The speed limit must be taken into account if it is lower than the speed that is possible with a maximum permitted lateral acceleration of the vehicle.

To achieve the target speed, the control device is set up to select a gear sequence that is suitable for decelerating the vehicle speed in the direction of the target setting speed v _target at the predetermined location before the corner of the road. The gear or gears are selected based on at least the weight of the vehicle, a current speed of the vehicle and a height difference, ie an inclination between a current position of the vehicle and a predetermined position in front of the curve section of the road. The vehicle can be operated in such a way that the speed on the sections of road with a downward slope, RSD, is increased to the speed limit of the road, for example the vehicle can roll. Using the map data relating to the radius of the curve, the gear sequence can determine that downshifting when driving on the RSD corresponds not only to the inclination of the downhill road section, but also on the basis of the radius of the curve of the upcoming RSC.

The control device is set up to control the transmission for engaging the selected gear. Furthermore, the control device can be set up to select the gear on the basis of the kinetic energy corresponding to the inclination of the road and the braking distance. The braking distance is in 4 designated with Sbr. The braking distance can be specified in advance. It can be selected so that the vehicle decelerates slowly from a downhill speed Vdh to the target speed v _target is obtained, with no sudden deceleration and ensuring the safety and comfort of the driver and the surrounding traffic. In this way, the braking distance can be chosen so that it is longer than a required minimum distance. In situations there may be a need to decelerate the vehicle very quickly, with the braking distance selected and / or determined in advance so that it corresponds to the shortest possible distance and / or the time to reach the target setting speed v _target is as short as possible. In this way the average speed of the vehicle can be increased compared to a scenario with long braking distances and it is possible to follow faster traffic on the road for a longer distance than would be possible with a braking distance with a softer braking. When determining the braking distance, the air resistance of the vehicle and a coefficient of friction can also be taken into account.

The control device is set up to select the gear based on gear data obtained by simulating the deceleration of the vehicle with different gears. The simulation can use an algorithm that calculates the appropriate gears that are required to decelerate the vehicle to the target speed at the end of the downhill inclined road section RSD and the braking effect or braking torque that is possible for the respective gear in the given situation. The weight of the vehicle, the braking distance, the slope, the coefficient of friction with respect to the road and the air resistance can be taken into account as variables in the simulation. By simulating different options of gears and gear sequences, the option is selected as the most suitable gear or gear sequence with the lowest engine speed and with which a sufficient braking torque and / or braking effect is achieved. In this way, an economical driving style can be achieved with a comfortable and safe speed control.

If the incline of the road is large, for example at an angle of 22 ° or more, it can be difficult to reach the target speed only by adjusting a gear or, on the other hand, only by specifying a long braking distance. The selected gear controls the vehicle speed towards the target speed. By “in the direction ...” it is meant that at least the target speed is being approximated or that in some cases the target speed has been reached completely. If the braking torque reached with the gear is not sufficient to reach the target speed completely, additional braking torque must be applied in order to reach the target speed. In this case, the control device is set up to calculate an additional braking torque, in addition to the braking torque which is achieved by the gear selection and which is required to achieve the target speed v _target , The control device can be set up to activate an auxiliary brake, which is a retarder and / or an electric brake, if additional braking torque is required. On the other hand or in addition, the control device can also be set up to set a compression release motor brake and / or an exhaust gas brake in order to increase the braking torque. The compression release engine brake and the exhaust brake are activated during gear selection and can be adjusted to generate a specific braking torque. After determining the braking distance, the control device can be set up to activate or request one or more auxiliary brakes. The use of wheel brakes based on friction should be avoided as far as possible, but may be necessary, e.g. if the braking torque of the available auxiliary brakes or the set compression release motor brake and / or the exhaust brake is not sufficient to decelerate the vehicle to the target speed v _target at the predetermined location.

The above objectives are also achieved by a method as defined in the appended claims. The present method relates to a control such that a vehicle reaches a set speed. The method is to be carried out by the control device described above and is arranged to be carried out when the vehicle is moving on a road with one or more sections of road with a downward slope, followed by a curve section of the road.

5 shows the steps of the procedure. The method is carried out by the control device described above and in this respect reference is made to the above description of the control device, the details of which are also fully applicable to the method described in more detail below. The first step of the process involves a determination ( s101 ) a target setting speed v _target for the vehicle at a predetermined location in front of a corner of the road based on at least the radius of the corner of the road and the weight of the vehicle. The predetermined location can be selected based on map data and this selection is made by the control device as described above.

The next step is the selection ( s102 ) a gear for decelerating the vehicle speed toward the target setting speed v _target at the predetermined location before the corner of the road. The gear is selected based on at least the weight of the vehicle, a current speed of the vehicle and a height difference between the current position of the vehicle and the corner portion of the road.

The next step involves control ( s103 ) of the gearbox for engaging the selected gear.

By executing the method in the manner described, it is possible for the driver to intervene when driving downhill on roads with several curve sections, in front of which road sections are inclined downhill. In some exemplary embodiments, the driver does not have to adapt the set speed or the braking torque while driving, since the target speed and / or the braking torque can be determined in advance and are therefore present. The method can be carried out in such a way that the functions of the method are activated in the control device of the vehicle when the downhill section of the road begins, so that the driver can concentrate on controlling the vehicle and there is no intervention in the speed control by means of manual use of the Brakes required.

In the process step of determination ( s101 ) the target speed v _target The speed can be calculated on the basis of a predetermined maximum lateral acceleration of the vehicle, optionally the inclination of the curve section of the road and optionally a current speed limit. The target speed is calculated so that there is no danger of the vehicle tipping over, which takes into account the maximum lateral acceleration of the vehicle. This is particularly important for situations where the speed limit in the curve is higher than the speed at the maximum lateral acceleration of the vehicle. The speed can be adjusted so that it is comfortable for the driver and / or passengers of the vehicle and follows the surrounding traffic as far as possible.

The process step of selection ( s102 ) a gear is still based on the kinetic energy due to the inclination of the road and a predetermined braking distance. The greater the inclination and the longer the braking distance and the weight of the vehicle, the greater the kinetic energy. The greater the kinetic energy, the greater the braking torque required. The braking distance is also extended. For example, for a situation in which the required maximum braking torque is calculated, the predetermined braking distance can be adjusted so that the target speed v _target is achieved.

In certain situations, the braking force generated by the gear selection is not sufficient to reach the target speed, which is why the method can still have a step in the calculation ( s104 ) one for reaching the target speed v _target required additional braking force, i.e. a braking torque in addition to the braking torque, which is determined by the step of selection ( s102 ) of the aisle is effected. The additional braking torque is generated by an auxiliary brake, which can be a retarder and / or an electric brake. Additionally or on the other hand, a compression release motor brake and / or an exhaust brake can also be set in order to provide a specific braking torque. The adaptation can be based on the calculation of the additional braking torque required. The control device can have a controller that is set up to adjust the compression release motor brake and / or the exhaust gas brake accordingly. In special cases, in which an even stronger braking is required, friction-based wheel brakes can be used in addition to the target speed v _target to reach. The step of selection ( s102 ) of the gear is based on gear data obtained by simulating a deceleration of the vehicle with different selected gears, with at least the weight of the vehicle, the braking distance and the inclination of the road being taken into account as a variable in the simulation.

The method steps can be carried out with the control device described above 50 , The control device may be an independent control device or it may be with the drive unit 2 be connected, which can be an internal combustion engine, for example, and thus it is then a control unit for the engine of the vehicle. The data required for the method are provided by connecting the control unit 50 via cable or a possibly wireless connection to the transmission or other devices, such as a GPS or other sensors and / or computers for simulation data, as in 2 is shown with a dashed line.

6 schematically explains a control device 50 , The control device 50 can be or have a computer. The control device is connected to the transmission and other devices of the vehicle via a connection. The term “connection” here means a communication connection which can be physical, such as an optoelectronic connection, or non-physical, such as a wireless connection, for example a radio wave connection or a microwave connection. The device 50 has a non-volatile memory 520 , a data processing unit 510 and a read / write memory 550 , The non-volatile memory 520 has a first memory area 530 , in which a computer program, for example an operating system, is stored for controlling the functions of the device 50 , The device 50 also has a bus controller, a serial communication port, input / output devices, an analog / digital converter, a time and data input and a transmission unit, an event counter and an interrupt controller (not shown). The non-volatile memory 520 also has a second memory area 540 ,

According to the present description, a computer program P is also provided, which has routines for executing the method for controlling a vehicle such that it reaches a set speed when driving on a road with one or more road sections leading downhill, followed by a curve section of the road Road. The computer program can be activated by the driver or the operator of the vehicle, or the control system can be set up to start the program when map data provide information about the road, which has one or more sections with a downward slope, followed by a curve section of the road according to predetermined ones Conditions. The computer program P has routines for determining ( s101 ) a target setting speed v _target for the vehicle at a predetermined location before the corner of the road based on at least a radius of the corner of the road and the weight of the vehicle. The computer program P also has routines for the selection ( s102 ) a gear for decelerating the vehicle speed toward the target setting speed v _target at the predetermined location before the curve portion of the road, the gear being selected based on at least the weight of the vehicle, a current speed of the vehicle, and a height difference between a current position of the vehicle and the curve portion of the road. Furthermore, the computer program P has routines for controlling ( s103 ) of the gearbox for engaging the selected gear. Furthermore, the computer program P can have routines for calculating ( s104 ), in addition to the braking torque due to the selection of a specific gear ( s102 ), an additional braking torque, which is required to the target speed v _target to reach. The program P can be in executable form or in compressed form in a memory 560 and / or in a read / write memory 550 can be saved.

Here is the data processing unit 510 described as a unit for performing a specific function, it means that the data processing unit 510 a certain part of that in memory 560 stored program or a certain part of the in the read / write memory 550 stored program executes.

The data processing unit 510 can with a data port 599 via a data bus 510 communicate. The non-volatile memory 520 is used for communication with the data processing unit 510 via a data bus 512 , The separate store 560 is used for communication with the data processing unit 510 via a data bus 511 , The read / write memory 550 is set up for communication with the data processing unit 510 via a data bus 514 ,

Are at the data connection 599 When data is received, it is temporarily stored in the second memory area 540 stored. If input data are temporarily stored, then the data processing unit can 510 execute the code as described above.

Parts of the methods described here can be controlled by the control device 50 by means of the data processing unit 510 be executed, the latter executing the program which is in the memory 560 or in the read / write memory 550 is filed. The device works 50 the program, the procedures described here are carried out.

The present description also relates to a vehicle with a control device 50 as described above. On the other hand, the vehicle has a computer-readable medium with a program code stored therein for executing the method steps as described above when the computer program is in the control device 50 expires or in a computer that is connected to the control device 50 connected is.

The above description of the present invention has been presented for illustrative and explanatory purposes only. It is not intended to be an exhaustive description or to limit the invention to the variants described. A variety of variations and changes will be apparent to those skilled in the art within the scope of the appended claims. The exemplary embodiments were chosen and described in more detail in order to be able to explain the basics of the invention and its practical applications in the best possible way and thus enable a person skilled in the art to understand the invention with regard to different embodiments and different modifications in accordance with the intended use.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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.

Patent literature cited

• US 2017/0159805 A1 [0004]

Claims (21)

Method carried out by a control device (50) of a vehicle (1) for controlling the vehicle in such a way that it reaches a set speed, the method being designed to be carried out when the vehicle (1) is driving on a road with or a plurality of road sections (RSD) with a downward slope, followed by a curve section (RSC) of the road, the vehicle (1) having an automatic or semi-automatic transmission and the method comprising the following steps: - determining (s101) a _target setting speed v _target for the vehicle ( 1) at a predetermined location (x ₁ ) in front of the curve section (RSC) of the street based on at least the radius of the curve section of the street and the weight of the vehicle (1), - selecting (s102) a gear for decelerating the vehicle speed in Direction to the _target setting speed v _target at the predetermined location (x ₁ ), the gear being selected au f based on at least the weight of the vehicle, a current speed of the vehicle and a height difference between a current position of the vehicle and the curve section (RSC) of the road, and - controlling (s103) the transmission to engage the selected gear. Procedure according to Claim 1 , wherein determining (s101) the _target setting speed v _target includes a calculation based on a predetermined maximum lateral acceleration of the vehicle (1), optionally the inclination of the curve section (RSC) of the road and optionally a current speed limit. Method according to one of the Claims 1 or 2 , wherein the selection (s102) of a gear is further based on the kinetic energy due to the inclination of the road section (RSD) with downward inclination and a predetermined braking distance (S _br ). Procedure according to Claim 3 , the predetermined braking distance (S _br ) being the shortest possible distance and / or corresponding to a time required to reach the _target setting speed v _target . Method according to one of the preceding claims, the method further comprising a step of calculating (s104) an additional braking torque which is required to achieve the _target setting speed v _target , in addition to the braking torque which is caused by the gear selection in step (s102) becomes. Procedure according to Claim 5 , wherein the additional braking torque is provided by an auxiliary brake, such as a retarder and / or an electric brake and / or by setting a compression release motor brake and / or an exhaust brake. Method according to one of the preceding claims, wherein the predetermined location is selected on the basis of map data. Method according to one of the preceding claims, wherein the step of selecting (s102) the gear is based on transmission data obtained by simulating the deceleration of the vehicle (1) with different gears, wherein at least the weight of the vehicle, the braking distance and the inclination of the downhill road section (RSD) are variables that are taken into account in the simulation. Method according to one of the preceding claims, wherein friction-based wheel brakes are additionally used to achieve the _target setting speed v _target . Computer program (P), the computer program having a program code to cause a control device (50) or a computer connected to a control device (50) to perform the steps according to one of the Claims 1 to 9 performs. Computer-readable medium with a program code stored therein for executing the method steps according to one of the Claims 1 to 9 , wherein the computer program runs on a control device (50) or on a computer connected to the control device. Control device (50) configured to control a vehicle such that the vehicle reaches a set speed, the vehicle configured to travel on a road with one or more road sections (RSD) with a downward slope, followed by a curve section (RSC) of the road , wherein the vehicle has an automatic or semi-automatic transmission and the control unit is set up to: - determine a _target setting speed v _target for the vehicle at a predetermined location (x ₁ ) before the curve section (RSC) of the road based on at least one radius of the Curve section (RSC) of the road and the weight of the vehicle (1), - selecting a gear for decelerating the speed of the vehicle (1) in the direction of the _target setting speed v _target at the predetermined location (x ₁ ) in front of the curve section (RSC) the street, the gear being selected based on at least the weight of the vehicle, a current speed of the vehicle and a height difference between a current position of the vehicle and the curve section of the road and - controlling the transmission to engage the selected gear. Control device (50) according to Claim 12 , wherein the _target setting speed v _{target is} calculated on the basis of a predetermined maximum lateral acceleration of the vehicle, optionally the inclination of the curve section of the road and optionally a current speed limit. Control device (50) according to one of the Claims 12 or 13 , set up for selecting the gear on the basis of the kinetic energy caused by the inclination of the road section (RSD) with downhill inclination and a predetermined braking distance (S _br ). Control device (50) according to Claim 14 , the predetermined braking distance (S _br ) being the shortest possible path and / or corresponding to the shortest possible time required to reach the _target setting speed v _target . Control device (50) according to one of the preceding Claims 12 - 15 , wherein the control device is configured to calculate an additional braking torque which is required to achieve the _target setting speed v _target . Control device (50) according to Claim 16 , wherein the control device is configured to activate an auxiliary brake, such as a retarder and / or an electric brake when an additional braking torque is required, and / or to set a compression release motor brake and / or an exhaust gas brake in order to increase the braking torque. Control device (50) according to one of the preceding Claims 12 - 17 , wherein the predetermined location (x ₁ ) is selected based on map data. Control device according to one of the preceding Claims 12 - 18 , wherein the control device is configured to select the gear based on gear data obtained by simulating a deceleration of the vehicle with different gears, the weight of the vehicle, the braking distance and the inclination of the road being variables which are taken into account in the simulation , Control device according to one of the preceding Claims 12 - 19 , wherein the control device is configured to engage friction-based wheel brakes or to request their use in order to achieve the _target setting speed v _target . Vehicle (1) with the control device according to one of the Claims 12 - 20 or according to the computer readable medium Claim 11 ,

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