DE102017207476A1 - Method and device for monitoring a brake system of a vehicle - Google Patents

Abstract

The present invention relates to a method for monitoring a brake system (106) of a vehicle (100), characterized in that in a step 200 of the testing, the brake system (106) is briefly activated for a test braking operation when the vehicle (100) has a known running state (120), and in a step (202) of determining a Bremsbelagreibwert (μ _BB) of the brake system (106) using the running state (120) and an acceleration value detected during the test braking process (122) is determined.

Description

Field of the invention

The invention relates to a method and a device for monitoring a brake system of a vehicle.

State of the art

In a friction brake, a braking effect is dependent on a friction coefficient and a contact pressure between the friction partners of the friction brake. If the braking effect decreases, then a reduction in the coefficient of friction may be the cause.

Disclosure of the invention

Against this background, a method and a device for monitoring a brake system of a vehicle according to the independent claims are presented with the approach presented here. Advantageous developments and improvements of the approach presented here are described in the dependent claims.

Advantages of the invention

Embodiments of the present invention may advantageously enable the state of the brakes of a vehicle to be monitored. This can be responded to a deterioration of the state in a timely manner, for example by the brakes are serviced. If maintenance is not yet required, a braking force can be adjusted to the current state to maintain consistent braking performance.

A method is provided for monitoring a brake system of a vehicle, the method being characterized in that in a step of testing the brake system is briefly activated for a test braking operation when the vehicle has a known driving condition and in a step of determining a brake pad friction coefficient the braking system is determined using the driving state and an acceleration value detected during the test braking operation.

Furthermore, a device for monitoring a brake system of a vehicle is presented, wherein the device is designed to execute the method according to one of the preceding claims in corresponding devices, to implement and / or to control.

Ideas for embodiments of the present invention may be considered, inter alia, as being based on the thoughts and findings described below.

When braking kinetic energy is converted into heat energy. This conversion takes place in a braking device by friction of a brake pad on a friction surface. For example, in a disc brake, the friction between a brake disc and at least one brake pad is generated by pressing the brake pad against the brake disc. The brake pad carries the brake pad. In a drum brake, at least one brake shoe is pressed against in particular the inside of a brake drum. The brake shoe carries the brake pad. A material pairing between a material or a surface of the friction surface and a material or a surface of the brake lining determines a brake pad friction coefficient. The brake pad friction coefficient may vary. For example, the material or the surface of at least one of the partners of the material pairing can change over time and / or due to external influences.

The brake pad friction coefficient can not be measured directly on a vehicle. In order to be able to correctly preset a contact pressure force of the brake pad against the friction surface in different brake situations, knowledge about a value of the brake pad friction value is required. Otherwise, the contact pressure can be set too low or too high, which can lead to too low a braking effect or too high a braking effect. Furthermore, a reduction in the brake pad friction value may signal the need to maintain the brake device.

In the approach presented here, therefore, a defined test braking process is carried out and calculated from the values of the brake pad friction value which are recorded thereby. The test braking process can be carried out with a predefined contact force. By the test braking process with a medium contact force, the braking effect can be checked. If the braking effect is too high, the result is an excessive acceleration value or deceleration value. If the braking effect is too low, the result is too low an acceleration value. The brake pad friction coefficient can be calculated from the acceleration value and known values of the braked vehicle.

For the test braking process, at least one wheel of an axle of the vehicle can be braked. The brake system of a vehicle generally acts on all wheels of the vehicle. If the braking devices are dimensioned differently on the wheels or axles of the vehicle, act different forces in the various braking devices. Through a Actuating the brake means of a single wheel or the brake means on an axle, the brake pad friction coefficient for the operated brake means can be detected with increased accuracy.

The step of testing may be performed when an inclination angle of the vehicle is within a tolerance range. The angle of inclination may refer to a lateral inclination and / or a longitudinal inclination of the vehicle. When the vehicle is slightly inclined, a subsurface under the vehicle is substantially flat. On a flat surface, a downgrade force does not or only slightly affects the result of the test braking process.

The step of testing may be performed when a road friction coefficient is greater than a road friction coefficient threshold. A road friction coefficient describes the coefficient of friction between the friction partners wheel and road. A changing road surface significantly influences the road friction coefficient. Meteorological factors also influence the road friction coefficient. On a slippery road, for example, a braked wheel can block and distort the measurement of the acceleration value.

The step of testing may be performed when a mass of the vehicle is within a tolerance range. An empty weight of the vehicle is known. Unknown portions of the mass of the vehicle are, for example, a load or persons in the vehicle. Fuels, such as fuel or lubricant also affect the mass. Known loading situations can be assigned predefined masses. For example, for a given number of passengers with a certain number of pieces of luggage, the mass may be known accurately enough to determine the brake pad friction coefficient.

The step of testing may be performed when the vehicle is unloaded and / or unmanned. In an unloaded and / or unmanned state, the mass of the vehicle is known very accurately. Only resources then influence the mass. In an electric vehicle in addition drops the variable weight of the fuel supply.

The brake pad friction coefficient may also be determined using a yaw rate of the vehicle during the test braking operation. A yaw rate describes an angular velocity of the vehicle about the vertical axis. The vehicle cracks when an asymmetric braking torque acts on the vehicle. The vehicle then pulls to one side. By the yaw rate, the braking effect or the Bremsbelagreibwert a single brake can be determined. The yawing can be countered. Then, the brake pad friction coefficient may be determined using a steering angle. Yawing can also be counteracted by targeted countermeasures via drive torques. The drive torques can also be used to determine the brake pad friction value.

The brake pad friction coefficient may also be determined using an acceleration value before and / or after the test braking operation. Before and after the test braking process, the vehicle is braked by resistors, such as air resistance and rolling resistance. These resistors continue to work during the test braking process. By determining the resistances, the brake pad friction value can be determined more accurately.

The brake pad friction coefficient may also be determined using a brake pressure value during the test braking operation. The brake pressure in a hydraulic brake line is proportional to the contact pressure of the brake pad against the friction surface via a piston surface.

It should be understood that some of the possible features and advantages of the invention are described herein with reference to different embodiments. One skilled in the art will recognize that the features of the monitoring method and apparatus may be suitably combined, adapted, or interchanged to yield further embodiments of the invention.

list of figures

• 1 zeigt eine Darstellung eines autonomen Fahrzeugs mit einer Vorrichtung zum Überwachen gemäß einem Ausführungsbeispiel; und
• 2 zeigt ein Ablaufdiagramm eines Verfahrens zum Überwachen gemäß einem Ausführungsbeispiel.

Embodiments of the invention will now be described with reference to the accompanying drawings, in which neither the drawings nor the description are to be construed as limiting the invention.

• 1 shows a representation of an autonomous vehicle with a device for monitoring according to an embodiment; and
• 2 FIG. 12 is a flowchart of a method of monitoring according to an embodiment. FIG.

The figures are only schematic and not to scale. Like reference numerals designate the same or equivalent features in the figures.

Embodiments of the invention

1 shows a representation of an autonomous vehicle 100 with a device 102 for monitoring according to an embodiment. The vehicle 100 Here is a driverless taxi, which can be called Robotaxi. The vehicle 100 is from a control unit 104 driven.

The device 102 is designed to be a brake system 106 or a braking system of the vehicle 100 to monitor. The brake system 106 includes a brake controller 108 and braking devices 110 on every bike 112 or each axis 114 . 116 of the vehicle 100 , The braking devices 110 are designed as touching friction brakes. The brake system 106 can be hydraulically or electronically actuated, for example. In response to a brake request by the controller 104 controls the brake control unit 108 the braking devices 110 via control lines with a hydraulic signal or an electrical signal, whereupon with a chassis of the vehicle 100 coupled brake pads of the brake devices 110 on with the wheels 112 coupled friction surfaces of the brake devices 110 be pressed. Here are the braking devices 110 designed as disc brakes, in which a vehicle-mounted brake caliper of the braking device 110 Brake pads with the brake pads leads and at least one actuator in the caliper by the signal of the brake control unit 108 is driven to the brake pads to one with the wheel 112 to press rotating brake disk.

The braking devices 110 on the different axles of the vehicle 100 are charged differently depending on the direction of travel. The vehicle 100 here has a preferred direction of travel. Therefore, the braking devices 110 at the front axle 114 larger dimensions than at the rear axle 116 ,

The device 102 is designed to brake pad friction values μ _BB between the brake pads and the friction surfaces to determine. To do this, the device sends 102 for a test braking process, a test signal 118 to the brake control unit 108 when through the control unit 104 a known driving condition 120 of the vehicle 100 is signaled. In particular, the vehicle 100 in the known driving condition 120 unoccupied or unladen and a mass of the vehicle 100 is known. The vehicle 100 can in the known driving condition 120 also drive on level ground. Furthermore, the wheels can 112 of the vehicle 100 have sufficient grip on the ground in the known driving condition.

In response to the test signal 118 controls the brake control unit 108 at least one braking device 110 an axis 114 . 116 at. The brake pads with a through the test signal 118 given force is pressed on the friction surface and the wheel 112 braked. For example, a known pressure acts on the pistons in the caliper. The braking device 110 is activated only for a short period of time. During the test braking process, an acceleration signal 122 from an accelerometer 124 of the vehicle 100 read. The acceleration sensor 124 is for example part of an ESP control device of the vehicle 100 , Using the driving condition 120 , the force and the acceleration signal 122 In the device, the brake pad friction coefficient is μ _BB certainly.

If only one wheel 112 is braked, resulting in a torque about a vertical axis or yaw axis of the vehicle 100 , The torque can be referred to as yaw moment. Without countermeasures, the torque turns the vehicle 100 around the vertical axis. This changes a yaw angle of the vehicle 100 , An angular velocity of the vehicle 100 about the vertical axis, or a yaw rate can from a yaw rate sensor of the vehicle 100 is read in and for determining the brake pad friction value μ _BB be used. The rotation rate sensor may also be part of the ESP control unit.

The torque around the vertical axis can be counteracted. For example, the controller 104 counter-steer. Then, a steering angle for determining the brake pad friction value μ _BB be used. Likewise, the torque may be due to a drive torque on at least one of the non-braked wheels 112 be counteracted. The drive torque may be used to determine the brake pad friction value μ _BB be used.

2 FIG. 12 is a flowchart of a method of monitoring according to an embodiment. FIG. The method monitors a brake system of a vehicle. The method can be used, for example, on a device such as that described in US Pat 1 is shown executed. The method has one step 200 of testing and a step 202 of determining. In step 200 During testing, the brake system is briefly activated for a test braking process. In this case, the brake system is activated when the vehicle has a known driving condition. In step 202 determining, a brake pad coefficient of the brake system is determined using the driving state and an acceleration value detected during the test braking operation.

In one embodiment, the step goes 200 testing one step 204 of checking ahead. In step 204 the check is made to see if the vehicle is the known one Has vehicle state. When in step 204 of checking the known vehicle state is detected, the step of testing can be performed.

The step 204 Reviewing involves multiple queries 206 . 208 . 210 , In the first query 206 it is queried whether the road is level, that is, whether an inclination angle of the vehicle is within a tolerance range. The angle of inclination can for example be read by a position sensor of the vehicle.

Whether the road is level can also be checked by reading out a slope information or slope information from a map at a position of the vehicle. In this case, a lying in front of the vehicle road section can be checked in advance.

In the second query 208 a query is made as to whether a road friction coefficient is greater than a threshold value. The road friction coefficient depends on a road surface and a road condition. The road surface and road conditions can also be read out of a map. Alternatively, the road surface and the road condition may be detected by an environment detecting device of the vehicle. Furthermore, the road friction coefficient is influenced by the weather. For example, the road friction coefficient of worn cobblestones may be less than the threshold when wet. The threshold may be, for example, 0.5. The weather can be detected by sensors of the vehicle or read by a weather service.

In the third query 210 is queried whether the vehicle is unmanned and / or unloaded. For example, it can be detected via an interior camera, whether people are in the vehicle. Level sensors on the axles or wheels may indicate a deflection of the chassis due to loading and / or passengers.

In one embodiment, the method includes the step 200 the step preceding the testing 212 selecting, in which the axis to be braked and / or the wheel to be braked is selected. The axes and / or wheels can be used for a sequence of steps 200 of testing alternately.

In one embodiment, the method includes a step 214 of recording. In step 214 of recording, various values of the vehicle can be recorded. For example, in step 214 recording the acceleration value or a longitudinal deceleration ax during the test braking operation.

The longitudinal delay ax can also be in one step 216 Plausibilisierens be plausibilized by a GPS of the vehicle.

In one embodiment, the step 214 recording already before the test braking process. The acceleration value is recorded before the test braking process. In step 202 By determining the acceleration values are offset against each other to exclude other influences than the test braking process.

In one embodiment, in step 214 the recording further recorded further values of the vehicle and in the step 202 of determining. For example, a steering angle, a yaw angle and / or a yaw rate are recorded.

When the brake pad friction coefficient has been determined, the brake pad friction coefficient may be determined in one step 218 Save stored locally or to a cloud.

In other words, a method is presented for monitoring the brake pad friction coefficient, in particular for highly automated and autonomous driving.

An extremely important physical parameter in brake systems is the friction coefficient or coefficient of friction between the brake disk and the brake pad. Since it is a coefficient, it is without unity and can - theoretically - be between 0 and 1. As a rule, it is around 0.4. This coefficient is not constant over the lifetime. It varies in part with the wear, strong at temperature differences, especially at high temperatures, partly with the brake pressure or the braking force, partly with the age of the brake pads, partly with the moisture, partly if salt was scattered and with the production batch of the brake pads.

To avoid confusion with the tire-road coefficient, the coefficient of friction is here Bremsbelagreibwert μ _BB called.

The brake pad friction coefficient μ _BB is proportional to the longitudinal deceleration during braking. A possible recuperation of hybrid vehicles or electric vehicles is not considered here.

mit

m:

Fahrzeugmasse in [daN]

a_x:

Verzögerung in Längsrichtung [m/s²]

r_roll:

Dynamischer Rollradius [m]

r_eff:

Effektiver Bremsscheibenradius beziehungsweise die Distanz zwischen der Radachse und der Bremskolbenachse [m]

p:

Bremsdruck [bar] oder [daN/cm²]

A_BK:

Bremskolbenfläche [cm²]

C*:

Bremsenkennwert#

The general formula which describes the relationship between the desired brake pressure and the is-deceleration. $$a_x=\frac{\text{p}\cdot {\text{A}}_{\text{BK}}}{\text{m}}\cdot \frac{{\text{r}}_{\text{eff}}}{{\text{r}}_{\text{rolling}}}\cdot \text{C}*$$

With

m:

Vehicle mass in [daN]

a _x :

Lag in longitudinal direction [m / s ² ]

r _roll :

Dynamic rolling radius [m]

r _eff :

Effective brake disc radius or the distance between the wheel axle and the brake piston axle [m]

p:

Brake pressure [bar] or [daN / cm ² ]

A _BK :

Brake piston area [cm ² ]

C *:

Brake coefficient #

$$C_{\text{Trommelbremse}}^{*}=\frac{2}{\frac{1}{{\mathrm{\mu }}_{BB}}-k}$$

The brake pad friction coefficient μ _BB is different for disc and drum brakes. $$C_{\text{disc brake}}^{*}=2\cdot {\mathrm{\mu }}_{BB}$$

$$C_{\text{drum brake}}^{*}=\frac{2}{\frac{1}{{\mathrm{\mu }}_{BB}}-k}$$

For hydraulic disc brakes, the brake pad friction coefficient can be μ _BB calculated as follows. $${\mathrm{\mu }}_{BB.ScHeibe}=m\cdot a_x\cdot \frac{r_{rOll}}{r_{eff}}\cdot \frac{1}{2\cdot p\cdot A_{BK}}$$

m:

Fahrzeugmasse in [daN]

a_x:

Verzögerung in Längsrichtung [m/s²]

r_roll:

Dynamischer Rollradius [m]

r_eff:

Effektiver Bremsscheibenradius [m]

F_klemm:

Klemmkraft des Bremssattels [daN]

Incidentally, the formula also applies to by-wire brake systems, whereby the clamping force is not the product of brake pressure and piston area. So the formula for by-wire disc brake systems is: $${\mathrm{\mu }}_{BB}=m\cdot a_x\cdot \frac{r_{rOll}}{r_{eff}}\cdot \frac{1}{2\cdot F_{klemm}}$$

m:

Vehicle mass in [daN]

a _x :

Lag in longitudinal direction [m / s ² ]

r _roll :

Dynamic rolling radius [m]

r _eff :

Effective brake disc radius [m]

F _clip :

Clamping force of the caliper [daN]

If the topology of the by-wire system is known, ie with / without self-amplification, a connection of the clamping force and the current is possible.

mit

A_BK:

Bremskolbenfläche = Radzylinderfläche [cm²]

k:

Faktor, welcher von der internen Trommelbremsengeometrie abhängt

For hydraulic drum brakes, the brake pad friction coefficient can be μ _BB calculated as follows. $${\mathrm{\mu }}_{BB.TrOmmel}=\frac{1}{\frac{2\cdot p\cdot A_{BK}}{m\cdot a_x}\cdot \frac{r_{eff}}{r_{rOll}}+k}$$

With

A _BK :

Brake piston surface = wheel cylinder surface [cm ² ]

k:

Factor, which depends on the internal drum brake geometry

As long as the brake pad friction coefficient μ _BB Not much changes, the driver intuitively corrects the braking process by increasing the brake pressure.

In Robo taxis, ie self-driving taxis, the driving task is no longer carried out by a driver, but by an artificial intelligence. Consequently, there is no steering wheel and pedals in such vehicles. All persons on board are passengers. The costs per kilometer driven can be reduced.

In highly automated or autonomous driving, the driver no longer has the task to monitor his vehicle, and thus also his braking system. He gets in this case, no feeling whether the brake system is still working properly. However, the vehicle does not notice that it is e.g. above-average braking - because, for example, the brake pad friction coefficient is only 0.2 - and just continue driving.

Since the braking pressure introduced by the driver is distributed to all four wheels, a monitoring of the brake pad friction coefficient via the above formula is only possible to a limited extent in vehicles with hydraulic brake system. The constant values for the brake piston area A _BK and the effective wheel radius r _eff are different for the front and rear axles. Thus, the brake pad friction coefficient μ _BB can not be determined clearly. Furthermore, the exact vehicle mass by the number of people, the luggage, the tank level and / or other loading weight is not known.

By the approach presented here, especially in autonomous vehicles, such as Robotaxis, the brake pad friction coefficient can be monitored or monitored over the lifetime by regular measurements, ie braking. For highly automated vehicles, this is also possible, but with small restrictions.

In the approach presented here, a partial braking without recuperation is regularly carried out, especially in autonomous vehicles. The following conditions apply.

The vehicle is only braked with one axle. As a result, the constant values for the brake piston area A _BK and the effective wheel radius r _{eff are} unambiguous.

The vehicle should preferably drive unmanned and unloaded. Then the mass is accurately known and constant, especially if the vehicle is an electric vehicle without a tank.

Ideally, the road should be flat and its coefficient of friction high enough to permit partial braking, for example at 0.5 g.

The step 212 Selecting the axis to be braked is relatively easy to accomplish. With a hydraulic brake system, the ESP only closes the two intake valves of the two wheels, which should not be braked. By-wire brake systems make it even easier. Only the wheels to be braked are energized and thus activated.

In step 214 When recording the longitudinal deceleration a _x, only the braking component can be utilized for recording. The delay due to the air and rolling resistance and other friction are deducted. In a vehicle with a burner is disengaged.

Thus, the relevant longitudinal deceleration a _x is equal to the relevant measured during the braking longitudinal deceleration a _{x measured during braking measured} minus the measured before braking longitudinal deceleration a _{x before braking.}

When braking is initiated with a defined nominal braking force, the braking is not of long duration. It is typical about one second for the determination of the longitudinal deceleration a _x before braking and as much for the determination of the longitudinal deceleration a _x during braking.

Furthermore, a difference in brake pad friction between the right and left sides of an axle can be determined. For this purpose, for example, an axle can be braked. In addition to the longitudinal deceleration a _x , the yaw angle Ω _z or the yaw rate is also measured. If the yaw angle Ω _{z is} not equal to zero, the vehicle pulls when braking wrong.

Advantageously, for this the road is very flat and falls e.g. not off to the curb. The pad friction coefficient differential detection can be performed either during straight braking, i. take place at a steering angle equal to 0 ° or when cornering, wherein when cornering these steering effects are taken into account in the calculation. The pad friction coefficient difference determination takes place without disturbing yaw rate-stimulating actuator interventions, e.g. Torquevectoring or differential lock controls.

In one embodiment, only one wheel is purposefully braked to deliberately create a skewing. The brake pad friction coefficient μ _BB is just as measurable. The resulting yaw angle Ωz and its derivative, ie the yaw rate are measured. This requires space on the street. The generated yaw angles / yaw rates are compared from the respective individual wheel brakes on the front axle, the same applies to the rear axle.

Alternatively, it can be actively counteracted to compensate for the skewing. The vehicle then drives straight ahead. The steering angle, which is necessary to realize a straight-ahead braking, is evaluated. The generated steering angles are compared from the respective individual wheel brakes on the front axle, the same applies to the rear axle.

In the case of a vehicle having wheel-individual or near-radome electric machines, these actuators may be used in their capacity as torque estimator to compensate for skewing. The vehicle then drives straight ahead. Evaluates the difference moment of the wheels of the axle, which is required to realize a straight-ahead braking. The differential moments generated are compared from the respective Einzelradbremsungen on the front axle, the same applies to the rear axle.

The Reibwertkontrollmessung can be performed without a defined target braking force. If different desired braking forces or braking pressures are set, the robustness of the friction brake and in particular the health of the brake system with respect. The brake pad can be observed and checked.

For example, when the brake pad friction coefficient μ _BB at a 10 bar braking is 0.35, at a 20 bar braking is 0.40 and at a 30 bar braking is 0.45, AND if the ambient temperature, the road condition, etc. are comparable, AND the above phenomenon before has not occurred, so the brake lining friction coefficient μ _BB was constant at each brake pressure, then a warning can be issued in any form, which states that the friction brake on the corresponding axle or the corresponding wheel should be checked by a specialist.

The approach presented here can be used for unmanned operation of Robotaxis or for highly automated vehicles, but small adjustments are required.

In an autonomous vehicle, in particular an electric vehicle, the mass is always the same when the vehicle is driving unmanned. In a highly automated vehicle, the weight of the occupants is estimated when determining the vehicle mass m, since in most cases no measuring device is present. A number of the occupants are about Sitzmattensorenoren o.ä. or via an interior camera well detectable. Information about luggage is not available. If a (semi-) active chassis control system is available, normal forces can be measured and / or estimated via suitable sensors.

In an autonomous vehicle, braking with only one axle is easily possible by e.g. Closure of intake valves. In a highly automated vehicle, single axis braking is easily accomplished by e.g. Closing the intake valves when the driver is not driving and the brake pedal is not pressed.

The determination of the longitudinal delay a _x is possible using the ESP sensor cluster or further longitudinal delay sensors. The longitudinal deceleration a _x can be made plausible via the GPS.

The approach presented here can also be used for trucks and motorcycles. The implementation on motorcycles is even easier, as the front and rear wheels can be braked independently.

Finally, it should be noted that terms such as "comprising," "comprising," etc., do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a multitude. Reference signs in the claims are not to be considered as limiting.

Claims (10)

Method for monitoring a brake system (106) of a vehicle (100), characterized in that in a step (200) of testing, the brake system (106) is briefly activated for a test braking operation when the vehicle (100) has a known driving state (120). includes, and in a step (202) of determining a Bremsbelagreibwert (μ _BB) of the brake system (106) using the running state (120) and an acceleration value detected during the test braking process (122) is determined. Method according to Claim 1 in which at least one wheel (112) of an axle (114, 116) of the vehicle (100) is braked in step (200) of testing for the test braking operation. Method according to one of the preceding claims, wherein the step (200) of testing is carried out when an inclination angle of the vehicle (100) lies in a tolerance range. The method of any one of the preceding claims, wherein the step (200) of testing is performed when a road friction coefficient is greater than a road friction coefficient threshold. A method according to any one of the preceding claims, wherein the step (200) of testing is performed when a mass of the vehicle (100) is within a tolerance range. Method according to Claim 5 in which the step (200) of testing is performed when the vehicle (100) is unloaded and / or unmanned. The method of any one of the preceding claims, wherein in step (202) of determining, the brake pad friction coefficient (μ _BB ) is further determined using a yaw rate of the vehicle (100) during the test braking operation. Method according to one of the preceding claims, wherein in step (202) of determining the brake pad friction coefficient (μ _BB ) is further determined using an acceleration value (120) before and / or after the test braking operation. The method of any one of the preceding claims, wherein in step (202) of determining, the brake pad friction coefficient (μ _BB ) is further determined using a brake pressure value during the test braking operation. Device (102) for monitoring a brake system (106) of a vehicle (100), wherein the device (102) is designed to implement, implement and / or control the method according to one of the preceding claims in corresponding devices.

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