DE102020107532A1 - Method for estimating the aerobalance of a motor vehicle - Google Patents

Abstract

The invention relates to a method for estimating the aerobalance of a motor vehicle (1) with an adjustable front wing (6) and with an adjustable rear wing (7), each of which can be adjusted under the control of an actuator, the motor vehicle (1) having a front axle (3) with front wheels (2) and a rear axle (5) with rear wheels (4), at least means (8) for determining the downforce on the front axle (3) and means (9) for determining the downforce on the rear axle (5) being provided are, with the front wing (6) and / or the rear wing (7) being adjusted according to a predefined profile at a defined driving speed of the motor vehicle (1) and based on the values of the downforce on the front axle (3) and the Downforce on the rear axle (5) the aerobalance is estimated as a function of the setting of the front wing (6) and the rear wing (7).

Description

The invention relates to a method for estimating the aerobalance of a motor vehicle.

There are motor vehicles with a front wing and a rear wing are known, which are also known as adjustable. The front wing and the rear wing cause an output force on the front axle FDF and an output force on the rear axle RDF on the rear axle due to the air flow on the front axle. As a result, a point CoP can be defined through which a resulting output force DF passes. The distance between the motor vehicle, i.e. the underbody, and the roadway on the front axle can also be determined as the driving height on the front axle FRH and the distance between the motor vehicle, i.e. the underbody on the rear axle, as the driving height on the rear axle RRH. From this, the Aerobalance AB can be determined as FDF / DF * 100%. The so-called rake, i.e. a measure of the inclination of the sub-floor, can also be determined as RRH - FRH.

Both the aerobalance and the rake depend on the setting of the front wing and the rear wing. The driving characteristics are also dependent on the aerobalance. For example, understeer on the front axle or oversteer on the front axle also depends on the aerobalance. A more common value of the aerobalance in GT racing vehicles is, for example, 35%.

In this case, however, it is problematic that the aerobalance is also incorrectly set due to unintentional or incorrect adjustments of the landing gear and / or the front wing and / or the rear wing, although this is not necessarily recognizable, for example, when driving. The effects of this unintended aerobalance change can be unintentional oversteer or understeer, which can be problematic when driving.

It is the object of the present invention to create a method for estimating the aerobalance of a motor vehicle which can also be carried out in an uncomplicated manner while driving.

The object is achieved with the features of claim 1.

One embodiment of the invention relates to a method for estimating the aerobalance of a motor vehicle with an adjustable front wing and with an adjustable rear wing, which are each adjustable controlled by an actuator, the motor vehicle having a front axle with wheels and a rear axle with wheels, with at least means for Determination of the downforce on the front axle and means for determining the downforce on the rear axle are provided, with the front wing and / or the rear wing being adjusted according to a predefined profile at a defined driving speed of the motor vehicle and based on the determined output values of the front axle and the downforce on the rear axle, the aerobalance is estimated as a function of the setting of the front wing and the rear wing. In this way, even in the event of malfunctions, such as a failure of an actuator for the adjustment or a power failure of the adjustment or a malfunction in the wheel suspension, the aerobalance during driving can be estimated and it can also be determined from this whether the system is working properly or whether there are errors. An output is understood to be an output force, that is to say a force, for example, of the wheels of an axle on the roadway.

mit FDF = der Abtrieb an der Vorderachse, DF als die Summe des Abtriebs an der Vorderachse FDF plus des Abtriebs an der Hinterachse RDF.It is particularly advantageous if the aerobalance AB is determined by means of the equation $$\text{AWAY}=\left(\text{FDF}/\text{DF}\right)*100\%$$

with FDF = the output on the front axle, DF as the sum of the output on the front axle FDF plus the output on the rear axle RDF.

This means that only the respective downforce of the front axle and the rear axle needs to be determined or estimated.

It is also advantageous if the rear wing and the front wing are adjusted simultaneously or at different times, or if only the front wing or only the rear wing are adjusted. In this way, the reaction of the output to the adjustment or to the set operating position can be determined. In this way, the output can be assigned to an operating position.

It is also advantageous if the driving speed of the motor vehicle is set to a predetermined setpoint speed, in particular is set by means of an automated speed control, also called a tempomat. The driving speed is not equal to zero and is preferably greater than 100 km / h, in particular 150 km / h or more. The speed control can be used to set a constant driving speed.

It is also expedient if the driving speed of the motor vehicle is set as a predetermined target speed and the following method steps are only carried out if the motor vehicle has a drives through a substantially straight route and / or an essentially flat route. This enables a constant driving speed to be achieved.

It is also advantageous if the profile of the adjustment of the front wing and / or the rear wing takes place between a first operating position, in particular a first operating end position, with a low output to a second operating position, in particular a second operating end position, with a high output. In this way, a reaction of the downforce as a function of the operating position can be determined in order to be able to estimate the aerobalance. Advantageously, the entire adjustment range is covered as far as possible, or at least as far as possible.

It is also useful if the profile of the adjustment begins in the first operating position, in particular in the first operating position, an adjustment is made to the second operating position, in particular the second operating position, and then an adjustment back to the first operating position, in particular to the first Operating end position, or that the profile of the adjustment begins in the second operating position, in particular in the second operating end position, there is an adjustment in the first operating position, in particular the first operating end position, and then an adjustment back in the second operating position, in particular in the second operating end position , he follows. A certain improved reliability in determining the aerobalance can thus be achieved by driving over the essentially sensible operating range.

It is also advantageous if the adjustment between the respective operating positions and / or operating end positions takes place several times and / or that the adjustment between the respective operating positions and / or operating end positions takes place directly, i.e. in one step or in several steps, linearly or in a non-linear function . A certain improved reliability in the determination of the aerobalance can thus also be achieved by repetition.

It is also advantageous if the values of the output on the front axle and / or the output on the rear axle take place by means of force sensors on the front axle and / or on the rear axle. Alternatively, other force sensors or units for determining the output can also be provided.

Furthermore, it is also expedient if a future target setting for the first operating position and the second operating position is made from the determined aerobalance AB. This defines the setting of the front wing and the rear wing for which maximum downforce and / or for which setting of the front wing and the rear wing a minimum downforce is achieved in order to be able to set this in the future. These values of the corresponding operating positions are advantageously stored in a memory and can later be read out from the memory as setpoint values as required.

• 1 eine schematische Darstellung eines Kraftfahrzeugs zur Erläuterung des erfindungsgemäßen Verfahrens,
• 2 eine weitere schematische Darstellung eines Kraftfahrzeugs zur Erläuterung des erfindungsgemäßen Verfahrens,
• 3 eine weitere schematische Darstellung eines Kraftfahrzeugs zur Erläuterung des erfindungsgemäßen Verfahrens,
• 4 ein Diagramm zur Erläuterung der Erfindung, und
• 5 ein Blockschaltbild zur Erläuterung des erfindungsgemäßen Verfahrens.

In the following, the invention is explained in detail using an exemplary embodiment with reference to the drawing. In the drawing show:

• 1 a schematic representation of a motor vehicle to explain the method according to the invention,
• 2 a further schematic representation of a motor vehicle to explain the method according to the invention,
• 3 a further schematic representation of a motor vehicle to explain the method according to the invention,
• 4th a diagram to explain the invention, and
• 5 a block diagram to explain the method according to the invention.

the 1 shows a schematic representation of a motor vehicle 1 with front wheels 2 on the front axle 3 and with rear wheels 4th on the rear axle 5 .

The car 1 has at least one front wing 6th or several front wings 6th , for example two front wings 6th , on and at least one rear wing 7th or several rear wings 7th , for example two rear wings 7th , which are individually adjustable. Actuators are provided for this, in particular electromotive actuators, so that the at least one front wing 6th from a first actuator and the at least one rear wing 7th is adjustable by a second actuator. Can also be used for several front wings 6th and / or for several rear wings 7th a plurality of actuators can also be provided in each case. For example, it is advantageous if two actuators are provided on at least one front wing and / or on at least one rear wing. For example, if there is only one rear wing 7th two actuators can also be provided.

Also at least is a means 8th to determine the downforce on the front axle 3 and means 9 to determine the downforce on the rear axle 5 intended. This means 8th , 9 are for example as force sensors on the front axle 3 and on the rear axle 5 and / or designed as an indirect observation system. Such an indirect observation system can, for example, have several Use sensor information to determine the current output forces.

The downforce on the front axle 3 is referred to as FDF, it is an output force. The downforce on the rear axle 5 is called RDF, it is also an output force.

This results in the total output force DF as DF = FDF + RDF, which acts on the resulting total output force DF at point CoP. The CoP is If behind the front axle and Ir in front of the rear axle 5 . The height of the subfloor 10 on the front axle is FRH and the height of the underbody on the rear axle is RRH. This results in the rake as rake = RRH - FRH.

The aerobalance AB results from AB = (FDF / DF) * 100% with FDF = the downforce on the front axle, DF as the sum of the downforce on the front axle FDF plus the downforce on the rear axle RDF. The Aerobalance AB depends on the setting of the front wing 6th and the rear wing 7th .

The method according to the invention provides that at a defined driving speed of the motor vehicle 1 the front wing 6th and / or the rear wing 7th is or are adjusted according to a predefined profile and from the values of the output FDF on the front axle determined in the process 3 and the output RDF on the rear axle 5 the Aerobalance AB depending on the setting of the front wing 6th and the rear wing 7th is estimated.

the 2 shows an example in which the front wing 6th and the rear wing 7th is set with a low downforce in a first operating position, in particular a first operating end position, a so-called low downforce position (LDF), in which only a low downforce is generated with little air resistance. A high top speed can be achieved in this way, for example.

the 3 shows an example in which the front wing 6th and the rear wing 7th is set in a second operating position, in particular a second operating end position, with a high output, a so-called high downforce position (HDF), in which a high output is generated. In this way, for example, a high cornering speed can be achieved.

The inventive method is according to 5 so in block 50 started that the driving speed of the motor vehicle is set to a predetermined target speed, in particular by means of an automated speed control, also called cruise control. The driving speed of the motor vehicle can be set as a predetermined target speed and the further method steps can be carried out.

The driving speed is preferably set to 100 km / h or more, in particular 150 km / h or more.

The following method steps can optionally only be carried out when the motor vehicle is traveling an essentially straight route and / or an essentially flat route.

Then in block 51 indicates that the test routine is active, for example in an instrument cluster or a screen, etc. Then the test routine, the measuring method according to the invention, is evaluated as active, see block 52 .

According to block 53 become the rear wing 7th and the front wing 6th adjusted to determine the reaction of the downforce to this adjustment, that is, the front wing 6th and / or the rear wing 7th are adjusted according to a predefined profile and from the values determined for the downforce on the front axle 3 and the output on the rear axle 5 the Aerobalance AB depending on the setting of the front wing 6th and the rear wing 7th estimated.

The rear wing can 7th and the front wing 6th can be adjusted simultaneously or with a time delay, or that only the front wing 6th or just the rear wing 7th is adjusted.

Also the profile of the adjustment of the front wing 6th and / or the rear wing 7th take place between a first operating position, in particular a first operating end position, with a low output to a second operating position, in particular a second operating end position, with a high output.

The profile of the adjustment can also begin in the first operating position, in particular in the first operating end position, and an adjustment into the second operating position, in particular the second operating end position, and then an adjustment back into the first operating position, in particular into the first operating end position, or that the profile of the adjustment begins in the second operating position, in particular in the second operating end position, an adjustment into the first operating position, in particular the first operating end position, takes place and then an adjustment back into the second operating position, particularly in the second operating end position, takes place.

The adjustment between the respective operating positions and / or operating end positions can also take place several times and / or the adjustment between the respective operating positions and / or operating end positions can take place directly, i.e. in one step or in several steps, linearly or in a non-linear function.

In block 54 an evaluation of the results of the downforce data is carried out so that an estimate of the aerobalance is made.

In block 55 is a determination of the target actuator position or the target setting of the front wing 6th and rear wing 7th made for the two operating positions HDF and LDF.

In block 56 the setting of the operating position HDF is enabled in the control unit. A future target setting for the first operating position and the second operating position is therefore made from the determined aerobalance AB.

the 4th shows a diagram in which the adjustment of the front wing 6th and the rear wing 7th from the LDF operating position to the HDF operating position is shown as an example. The adjustment takes place from the LDF operating position abruptly to the HDF operating position, then again after a waiting break abruptly to the LDF operating position and then after a further waiting break gradually to the HDF operating position and then again after a further waiting break abruptly back to the LDF- Operating position. Other adjustment profiles can also be provided and carried out.

List of reference symbols

1

Motor vehicle

2

Front wheel

3

Front axle

4th

Rear wheel

5

Rear axle

6th

Front wing

7th

Rear wing

8th

middle

9

middle

10

Subfloor

50

block

51

block

52

block

53

block

54

block

55

block

56

block

Claims (10)

Method for estimating the aerobalance of a motor vehicle (1) with an adjustable front wing (6) and with an adjustable rear wing (7), each of which can be adjusted controlled by an actuator, the motor vehicle (1) having a front axle (3) with front wheels (2 ) and a rear axle (5) with rear wheels (4), at least means (8) for determining the downforce on the front axle (3) and means (9) for determining the downforce on the rear axle (5) being provided, with a defined driving speed of the motor vehicle (1) the front wing (6) and / or the rear wing (7) is or are adjusted according to a predefined profile and from the determined values of the output on the front axle (3) and the output on the rear axle (5) the aerobalance is estimated as a function of the setting of the front wing (6) and the rear wing (7). Procedure according to Claim 1 , characterized in that the aerobalance AB is determined from the equation $$\text{AWAY}=\left(\text{FDF}/\text{DF}\right)*100\%$$

with FDF = the output on the front axle (3), DF as the sum of the output on the front axle (3) FDF plus the output on the rear axle (5) RDF. Procedure according to Claim 1 or 2 , characterized in that the rear wing (7) and the front wing (6) are adjusted simultaneously or at different times or that only the front wing (6) or only the rear wing (7) are adjusted. Procedure according to Claim 1 , 2 or 3 , characterized in that the driving speed of the motor vehicle (1) is set to a predetermined target speed, in particular is set by means of an automated speed control, also called tempomat. Procedure according to Claim 1 , 2 , 3 or 4th , characterized in that the driving speed of the motor vehicle (1) is set as a predetermined target speed and the implementation of the following method steps is only carried out when the motor vehicle (1) is driving an essentially straight route and / or an essentially flat route. Method according to one of the preceding claims, characterized in that the profile of the adjustment of the front wing (6) and / or the rear wing (7) between a first operating position, in particular a first operating end position, with a low output to a second operating position, in particular a second End of operation position, takes place with a high output. Procedure according to Claim 6 , characterized in that the profile of the adjustment begins in the first operating position, in particular in the first operating end position, an adjustment into the second operating position, in particular the second operating end position, and then an adjustment back into the first operating position, in particular into the first operating end position , takes place or that the profile of the adjustment begins in the second operating position, in particular in the second operating end position, an adjustment into the first operating position, in particular the first operating end position, takes place and then an adjustment back into the second operating position, in particular into the second operating end position, he follows. Procedure according to Claim 6 or 7th , characterized in that the adjustment between the respective operating positions and / or operating end positions takes place several times and / or that the adjustment between the respective operating positions and / or operating end positions takes place directly, i.e. in one step or in several steps, linearly or in a non-linear function. Method according to one of the Claims 6 , 7th or 8th , characterized in that the values of the output on the front axle (3) and / or the output on the rear axle (5) by means of force sensors on the front axle (3) and / or on the rear axle (5) and / or by means of an observation system, which is fed by several sensors can be determined. Method according to one of the preceding claims, characterized in that a future target setting for the first operating position and the second operating position is made from the determined aerobalance AB.

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