DE102019124584B3 - Method for supporting a driver of a motor vehicle in the event of a targeted power limitation of a drive device and assistance system - Google Patents

Abstract

Method and assistance system (10) for supporting a driver of a motor vehicle in the event of a targeted power limitation of a drive device (1). By means of a monitoring device (2), a retrievable power of the drive device (1) is deliberately restricted depending on an operating condition of the drive device (1). In the event of such a limitation of the available power, an assistance device (3) issues a message about the power limitation to the driver. The message informs the driver of the effect the power limitation has on at least one driving characteristic of the motor vehicle.

Description

The present invention relates to a method and an assistance system for supporting a driver of a motor vehicle in the case of a targeted power limitation of a drive device with at least one internal combustion engine.

Vehicles currently in series production are generally applied with so-called component protection. Exhaust-leading components such. B. turbines of the turbocharger, lambda probes, catalytic converters or particle filters, if necessary protected against excessively high exhaust gas temperatures. This component protection can take place with the help of sensor-based and / or model-based temperature information. According to the current state of the art, these systems largely manage without sensor information and work with modeled temperature information. These temperatures are calculated using information available in the engine control unit. In general, component protection is achieved by leaving the stoichiometric (lambda = 1) fuel-air mixture in the direction of rich (lambda <1) or in the direction of lean (lambda> 1).

Thanks to these component protection measures, the engine is largely able to provide the applied power (nominal power) even under difficult conditions (poor fuel quality, high intake air temperature, high coolant temperature, low ambient pressure). In very rare exceptional cases, it may not be possible to enrich or lean the air-fuel mixture further. Then, in order to protect the components carrying the exhaust gas from thermal overload, the output of the engine must be limited.

For future exhaust emission regulations, leaving the stoichiometric fuel-air mixture (lambda = 1) will probably no longer be permitted or only permitted to a very limited extent. Engine concepts for these future exhaust emission regulations will have to implement the component protection described above using other measures. These measures, such as B. a water injection into the combustion chamber or a water cooling of the exhaust valves, the exhaust manifold and / or the turbine as well as an increase of the turbine output for further energy extraction from the exhaust gas by recuperation of electrically assisted turbochargers or by increasing the boost pressure will probably not be straightforward over longer periods of time be representable.

Therefore, a limitation of the engine power that can be called up, which is only necessary in very rare exceptional cases today, will very likely occur more frequently in the future.

In contrast, the object of the present invention is to enable such power limitations to be implemented in a particularly safe and convenient manner for the occupants of the vehicle.

This object is achieved by the method with the features of claim 1 and by the assistance system according to claim 10. Preferred developments of the invention are the subject matter of the subclaims. Further advantages and features of the present invention emerge from the general description and the description of the exemplary embodiment.

The method according to the invention serves to support a driver or driver of a motor vehicle in the event of a targeted power limitation of a drive device with at least one internal combustion engine. In this case, by means of at least one monitoring device, a retrievable power of the drive device is specifically restricted depending on at least one operating condition of the drive device. By means of the monitoring device, the retrievable power of the drive device can be specifically limited if, under the present operating conditions, damage to the drive device is to be expected without leaving a defined fuel-air mixture, in particular the stoichiometric fuel-air mixture (lambda = 1). In the event of such a limitation of the available power, at least one message about the power limitation is output to the driver by means of at least one assistance device. The message informs the driver of the effects that the power limitation has on at least one driving characteristic of the motor vehicle.

The method according to the invention offers many advantages. The notification about the power limitation and its effects on the driver offers a considerable advantage. This enables particularly safe driving because the driver is not surprised by the lack of performance and knows what to expect due to the performance limitation. In this way, driving behavior and expectations can be adapted to the vehicle and the journey can be continued comfortably and safely.

It is a particular advantage of the invention that the driver not only knows that the full nominal power cannot be called up, but also knows its effects on the intended driving maneuvers. For example, it doesn't have to be in a manual looked up or based on empirical values. The invention therefore offers considerable advantages over, for example, an engine control light which indicates to the driver a technical fault or emergency operation of the drive device.

The message preferably informs the driver of the maximum speed that can be achieved with the motor vehicle, taking into account the power limitation. In other words, information is provided about the maximum speed that can currently be reached with the reduced nominal power or the power currently available. The maximum speed communicated to the driver corresponds in particular at least approximately to the maximum speed actually achievable and is z. B. a theoretically achievable maximum speed. When the maximum achievable speed is mentioned below, the maximum achievable speed is preferably meant, taking into account the power limitation.

Such a configuration offers a considerable improvement in safety when driving. The achievable maximum speed is usually a much more descriptive figure than other performance data. If, for example, an overtaking maneuver is imminent, the maximum achievable maximum speed can be used to estimate particularly well whether or not a fast and safe overtaking is possible under the given boundary conditions. Most users have little knowledge of what to do with an abstract quantity or just a hint about the degradation.

It is also possible and preferred that the message informs the driver of the effect of the power limitation on another driving characteristic of the motor vehicle. The driving characteristic can represent the acceleration and / or the torque, for example. It is also possible for the driver to be informed by the message about how much power can still be called up, taking the power limitation into account. Provision can also be made for the driver to be informed of at least one characteristic value derived from the power limitation. Such a parameter can be, for example, a changed travel duration or a changed arrival time. It is also possible that such a parameter describes a changed range of the vehicle, for example due to changed fuel consumption or electrical energy consumption.

In an advantageous embodiment, the achievable maximum speed is displayed as a number, in particular a decimal number, on a dashboard. In particular, for this purpose the dashboard comprises at least one display device and, for example, an instrument cluster and / or tachometer or the like. Such a number is particularly easy and reliable to perceive, so that there are no unnecessary distractions. The maximum speed that can be achieved can also be illustrated by at least one symbol and / or at least one dimensionless scale. For this purpose, a bar display can be provided, for example, the bar length corresponding to the maximum achievable speed.

In a particularly preferred embodiment, a scale of a speedometer is adapted as a function of the maximum speed that can be achieved. In this way, the achievable maximum speed can be illustrated particularly advantageously. Since the speedometer is usually always in view when driving, the change in the achievable maximum speed can be perceived reliably and comfortably.

The speedometer is in particular part of a dashboard and can be integrated into an instrument cluster. The scale can at least partially be designed analogously. It is also possible for the scale to be provided by at least one electronic display. In particular, the scale is optically adapted. The adjustment of the scale can relate to graduation lines and / or numerical values for the graduation lines and / or the background. It is also possible for at least one symbol and / or a number or the like to be displayed on the speedometer and in particular in the scale, whereby the achievable maximum speed is illustrated. In particular, the scale comprises at least graduation lines and / or numerical values for the graduation lines and / or a background.

It is possible and preferred that the visibility of the speedometer and preferably the scale is reduced at least partially up to the achievable maximum speed. It is also possible and preferred that the scale below the achievable maximum speed is visually displayed differently than above this speed. It is also possible for the scale to be at least partially hidden and / or darkened and / or discolored and / or covered above the achievable maximum speed. In particular, the scale below the achievable maximum speed has a different color and / or brightness than above the achievable speed. In particular, the scale above the achievable maximum speed is at least partially colored and, for example, has a red background. Other suitable colors are also possible. The optically changed representation of the scale can relate to graduation lines and / or numerical values and / or the background. In particular, the scale of the speedometer is dynamically adapted to the maximum achievable speed. Such configurations offer a particularly simple and at the same time clear perception of the changed maximum speed.

It is possible that at least one warning is issued when approaching and / or reaching the (currently) achievable maximum speed. Such a warning can be given visually and / or acoustically and / or haptically. This means that the driver is not surprised if it is no longer possible to increase the speed further.

In particular, the achievable maximum speed is determined at least by determining or balancing the driving resistances and the limited power of the drive device. In particular, sensor signals for the driving resistances are recorded for this purpose. For this purpose, sensor signals on the drive side are preferably also recorded. For example, at least one sensor device is assigned to the drive device and the rest of the vehicle. As an alternative or in addition to sensory detection, values determined in advance and stored in the assistance device can also be used. In particular, at least one algorithm for at least approximately calculating the maximum speed that can be achieved at a given power limit is stored in the assistance device.

It is possible that the output of the message can be deactivated. In this way, the information can be deliberately suppressed. It is also possible for the message and, for example, the information content to be at least partially adaptable.

For example, a menu can be provided for this purpose, via which corresponding presettings can be entered and selected.

In a particularly advantageous embodiment, the motor vehicle is suitable and designed for at least partially autonomous driving. Partially autonomous or autonomous driving may be possible. The limitation of the available power for controlling the at least partially autonomous driving is taken into account. For example, the controller for autonomous driving can reliably decide, with the help of appropriate mathematical calculations, whether or not certain driving maneuvers can also be carried out safely while the power is being limited.

The assistance system according to the invention is provided for a motor vehicle and serves to support a driver in the event of a power limitation of a drive device. A retrievable power of the drive device can be specifically restricted as a function of at least one operating condition of the drive device by means of at least one monitoring device. The monitoring device is suitable and designed to specifically limit the available power of the drive device if the drive device is damaged under the present operating condition without leaving a defined fuel-air mixture, in particular the stoichiometric fuel-air mixture (lambda = 1) is to count. In the case of such a limitation of the available power, at least one message about the power limitation can be output to the driver by means of at least one assistance device. The assistance device is suitable and designed to use the message to inform the driver of the effect the power limitation has on at least one driving characteristic of the motor vehicle.

The assistance system also solves the task in a particularly advantageous manner and enables significantly safer and more comfortable driving, even when power limitations are to be expected more frequently. In particular, the assistance system is suitable and designed to be operated according to the preceding method. In particular, the drive device, the monitoring device and the assistance device are designed as described above for the method according to the invention. In particular, the method described above is designed so that the assistance system according to the invention can then be operated. In particular, the assistance system is operated according to the method described above. In particular, the assistance system comprises at least one operative connection with the combination instrument and preferably with the speedometer and / or at least one other suitable user interface for outputting the message. In particular, the configurations of the assistance system are also provided for the method. In particular, the method and the assistance system relate to forward travel and preferably also to reverse travel of the vehicle.

According to the invention, the monitoring device is suitable and designed to specifically limit the available power of the drive device if (long-term and / or short-term) damage to the drive device is to be expected under the present operating condition without leaving a defined fuel-air mixture. The defined fuel-air mixture is in particular a stoichiometric fuel-air mixture, preferably with lambda = 1. According to the invention, the drive device comprises at least one internal combustion engine. This is particularly advantageous if component protection is otherwise required without leaving the defined fuel-air mixture could not be implemented. The defined fuel-air mixture is determined in particular by an exhaust gas emission regulation to be taken into account. The operating conditions under which damage to the drive device can be expected are stored in the monitoring device in particular.

In particular, the monitoring device is suitable and designed to specifically limit the retrievable power of the drive device to extend the range and / or to protect an electrical energy storage device and / or to protect power electronics. In such an embodiment, the drive device comprises in particular at least one electric machine and the motor vehicle is preferably designed as an electric vehicle and / or hybrid vehicle.

The at least one operating condition relates in particular to the fuel quality and / or intake air temperature and / or coolant temperature and / or the ambient pressure. It is also possible that the at least one operating condition relates to the state of charge and / or thermal state of an electrical energy storage device or traction battery. The at least one operating condition can also relate to the thermal state of power electronics and / or an electric drive machine. The power limitations necessary under such operating conditions can be implemented particularly safely and conveniently with the invention.

In particular, there is a notification of a current (present) and / or upcoming power limit. It is also possible for a notification to be made that the power limitation has ended. The notification can take place in time before an imminent performance limitation and / or at the same time as the performance limitation. In particular, the driver is continuously informed of the effects of the power limitation during the power limitation. In particular, the driver is informed of a change in the power limitation. In particular, the driver is informed of the end of the power limitation. The message can include visual and / or acoustic and / or haptic cues.

The power of the drive device that can be called up in normal operation or without power limitation corresponds in particular to a nominal power, also called nominal power, of the drive device. In particular, the nominal power of the drive device is reduced by the power limitation.

In particular, the power of the drive device that can be called up during a power limitation corresponds to only part of the nominal power of the drive device. The drive device comprises at least one internal combustion engine.

In particular, the limitation of the available service is only temporary or as an exception to normal operation. In particular, the power is not limited due to a technical fault in the drive device, but rather due to the operating conditions under which the drive device is operated. In particular, the power limitation takes place in order to comply with emission limit values for the exhaust gases of the drive device and preferably as an alternative to enriching and / or leaning the fuel-air mixture.

Further advantages and features of the present invention emerge from the exemplary embodiments which are explained below with reference to the accompanying figures.

• 1 eine stark schematisierte Darstellung eines erfindungsgemäßen Assistenzsystems;
• 2 eine stark schematisierte Darstellung des Assistenzsystems nach 1 mit einem Tachometer;
• 3 der Tachometer der 2 in einem angepassten Zustand; und
• 4 der Tachometer der 2 in einem anderen angepassten Zustand.

In the figures show:

• 1 a highly schematic representation of an assistance system according to the invention;
• 2 a highly schematic representation of the assistance system 1 with a speedometer;
• 3 the speedometer of the 2 in an adapted condition; and
• 4th the speedometer of the 2 in another adjusted state.

1 shows an assistance system according to the invention 10 for a motor vehicle not shown here. The assistance system 10 is operated here according to the method according to the invention and is used to support a vehicle driver in the event of a targeted power limitation of a drive device 1 . The drive device 1 can for example be provided by an internal combustion engine or an electrical machine or a combination of these two.

Under certain operating conditions it can happen that the full nominal drive power (nominal power) cannot be called up. There is also a monitoring device here 2 provided, which is designed for example as an engine management system or a control unit or the like.

The monitoring device 2 enables so-called component protection in order to, for example, provide exhaust-gas-carrying components in an embodiment for an internal combustion engine protect against high temperatures. So can the drive device 1 be protected from damage even under difficult conditions and, for example, with poor fuel quality or high intake air temperature or high coolant temperature or low ambient pressure.

In order to be able to comply with the corresponding exhaust emission regulations, the monitoring device takes 2 for component protection there is then no or only a very small permissible change in the stoichiometric fuel-air mixture. The monitoring device 2 however, sets component protection through a targeted restriction of the available nominal power of the drive device 1 in front.

In an embodiment of the motor vehicle as a hybrid vehicle or as an electric vehicle with a purely electric drive, the monitoring device 2 Carry out component protection, for example, when a critical charge state or critical temperatures of the battery or power electronics occur.

Then the monitoring device limits 2 the drive power of the electrically designed drive device 1 . In certain driving programs, the drive power can also be limited to maximize the range.

The one from the monitoring device 2 Any performance limitation made is an assistance facility 3 communicated. The assistance facility 3 then outputs a message about the current or upcoming power limitation to the vehicle driver. The message provides information about the effect that the power limitation has on a driving characteristic of the motor vehicle.

The driving quality concerns z. B. the maximum achievable maximum speed due to the power limitation (v_max). The assistance facility calculates for this 3 By balancing the driving resistances and the currently available drive power, the currently theoretically achievable maximum speed. There is also the assistance facility 3 for example with a sensor device 6th for the acquisition of vehicle-side sensor signals.

The assistance facility also takes this into account 3 sensor signals recorded on the drive side. The monitoring device 2 comprise a sensor device not shown here.

The vehicle-side sensor signals expediently contain information for calculating the driving resistance. These sensor signals are generated by the assistance device 3 processed and used to determine the maximum achievable maximum speed. The currently achievable maximum speed as information is particularly easy for the vehicle driver to recognize and evaluate and can be related particularly well to the speed currently being driven.

The assistance facility 3 then shows the currently achievable maximum speed on a dashboard 4th and for example an instrument cluster arranged there 14th at. In the instrument cluster 14th the achievable maximum speed can be displayed as a decimal number, for example. In particular, the current speed is also displayed in the instrument cluster.

With reference to the 2 to 4th an embodiment is described below in which the maximum achievable maximum speed by adapting a scale 15th a speedometer 5 is illustrated.

The 2 the scale 15th of the speedometer 5 in normal operation without a power limitation of the drive device 1 . The scale 15th shows the full speed range here.

In the 3 is the speedometer 5 shown during a power limitation. The speed range above the achievable maximum speed is highlighted in color (shown here with hatching). In the example shown here, the currently achievable maximum speed is 220 km / h. The speed range highlighted in color is adapted continuously in accordance with the maximum achievable speed calculated in each case.

The 4th shows a speedometer 5 , at which the speed range in the scale that cannot be reached due to the power limitation 15th has been hidden.

In addition, a warning can be displayed to the driver when he reaches the maximum achievable speed. This warning can be given visually, acoustically, or haptically. The display of the currently achievable maximum speed can be selected so that it can be switched off by the driver if the driver deliberately wants to suppress this information.

List of reference symbols

1

Drive device

2

Monitoring device

3

Assistance facility

4th

dashboard

5

Speedometer

6th

Sensor device

10

Assistance system

14th

Instrument cluster

15th

scale

Claims (10)

A method for supporting a driver of a motor vehicle in the event of a targeted power limitation of a drive device (1) with at least one internal combustion engine, whereby a retrievable power of the drive device (1) is specifically restricted by means of at least one monitoring device (2) depending on at least one operating condition of the drive device (1) can be and whereby by means of the monitoring device (2) the retrievable power of the drive device (1) can be specifically restricted if under the present operating conditions without leaving a defined fuel-air mixture, in particular the stoichiometric fuel-air mixture (lambda = 1), with damage to the drive device (1) is to be expected and at least one message about the power limitation is output to the driver by means of at least one assistance device (3) in the event of such a limitation of the available power, and wherein the driver is informed by the message about the effect of the power limitation on at least one driving characteristic of the motor vehicle. Method according to the preceding claim, wherein the message informs the driver of the maximum speed that can be achieved with the motor vehicle, taking into account the power limitation. Method according to the preceding claim, wherein the maximum achievable speed is displayed as a number on a dashboard (4) of the motor vehicle. Method according to one of the two preceding claims, wherein a scale (15) of a tachometer (5) is adapted as a function of the maximum achievable speed in order to illustrate the maximum achievable speed. Method according to the preceding claim, wherein the scale (15) is reduced at least partially up to the achievable maximum speed and / or wherein the scale (15) below the achievable maximum speed is represented optically differently than above this speed. Method according to one of the four preceding claims, wherein at least one warning is issued when approaching and / or reaching the achievable maximum speed. Method according to one of the five preceding claims, wherein the achievable maximum speed is determined at least by balancing the driving resistances and the limited power of the drive device (1). Method according to one of the preceding claims, wherein the output of the message can be deactivated. Method according to one of the preceding claims, wherein the motor vehicle is suitable and designed for at least partially autonomous driving, and wherein the limitation of the available power is taken into account for controlling the at least partially autonomous driving. Assistance system (10) for a motor vehicle to support a driver in the event of a power limitation of a drive device (1) with at least one internal combustion engine, whereby by means of at least one monitoring device (2) a retrievable power of the drive device (1) depending on at least one operating condition of the drive device (1 ) can be deliberately restricted and the monitoring device (2) is suitable and designed to deliberately restrict the power of the drive device (1) that can be called up if, under the present operating condition, without leaving a defined fuel-air mixture, in particular the stoichiometric fuel-air mixture ( Lambda = 1), damage to the drive device (1) is to be expected and at least one message about the power limitation is output to the driver by means of at least one assistance device (3) in the event of such a limitation of the available power r and wherein the assistance device (3) is suitable and designed to use the message to inform the driver of the effect the power limitation has on at least one driving characteristic of the motor vehicle.

Images