Mercedes-benz Aktiengesellschaft

Daimler-benz Ag

Daimler Chrysler Ag

Daimler Ag

Richard Zimmer

Manfred H Burckhardt

Armin Muller

Rainer Freitag

Reinhold Schoeb

Sinan Kazan

Martin Klarer

Armin Mueller

Andreas Faulhaber

Gerd Eilert

Rainer Spiecker

Heinz Leiber

Werner Reichelt

Franz Brugger

Gerhard Kurz

Volker Entenmann

Lutz Eckstein

Ingo Dudeck

Horst Grossner

Harry Troester

Markus Hess

Eberhard Pfeifle

Walter Kostelezky

Andy Yap

Erich Waxenberger

Thomas Unselt

Thomas Roehrig-Gericke

Werner Schneider

Siegfried Schlosser

Uwe Petersen

Cornelia Voigt

Wolfgang Gautsch

Wofgang Lauer

In a method and apparatus for radio-based issuing of warnings of hazards to the driver of a vehicle having a data receiver, the data receiver receives data from at least one data transmitter of at least one other vehicle, and evaluates the received data. The received data comprising information about the position, speed and direction of travel of the transmitting vehicle. The approach speed between the receiving vehicle and transmitting vehicle are determined in order to evaluate the received data in the receiving vehicle. According to the invention, in order to evaluate the received data in the receiving vehicle, the distance between the transmitting vehicle and the receiving vehicle is determined, and it is determined whether information is output to the driver, based on the distance between the transmitting vehicle and receiving vehicle, and based on the approach speed between the transmitting vehicle and receiving vehicle.

Device and method for radio-based danger warning

An automatic brake and steering system and method for a vehicle contains a sensor unit for sensing vehicle state and characteristic variables, and ambient conditions. Furthermore, a control unit and actuator devices are provided for setting the vehicle brake system and/or the vehicle steering system. In order to be able to carry out automatic avoidance maneuvers with maximum safety, an avoidance route is determined if there is an obstacle in the path of the vehicle. Thereby, if there is a further obstacle on the avoidance route, the strategy for determining the avoidance route is applied once more. If it is not possible to find a collision-free avoidance route, that route on which the difference between the remaining braking distance and the remaining distance from the obstacle is smallest is selected.

Automatic brake and steering system and method for a vehicle

For the determination of the friction/slip characteristics of the tires of a road vehicle which is equipped with an antilock system designed for an individual wheel control, in an initial phase of a controlled braking, only the wheel brake of an individual vehicle wheel is acted upon by brake pressure and the latter is dimensioned so that the result is the initial retardation in accordance with the driver's wish. During this initial test phase of the braking, the absolute brake slip .lambda..sub.B as well as the friction utilization .mu..sub.B linked therewith is continuously determined as soon as, as a result of just the braking of the test wheel, the vehicle retardation z increases no further and/or the braked vehicle wheel is more strongly retarded than corresponds to a predetermined threshold value, the test braking is interrupted and the braking is continued by pressure action on the further vehicle wheels; corresponding test braking phases are carried out in cyclic sequence for all guidance wheels.

Process and system for determination of friction/slip characteristics of

Process for determination of friction/slip characteristics of the tires

Brake system with adjustably variable front/rear axle braking force

An apparatus and method adapts response slip threshold values for a drive slip and/or a brake slip control system to the tires fitted to a motor vehicle. The drive torque provided at the driven vehicle wheels is determined from measured operating data such as fuel supply and/or combustion air supply, engine speed and total transmission ratio of the drive train of the vehicle. From this determination, the adhesion coefficient .mu..sub.a utilized is determined with a predetermined or measured axle load at the driven vehicle wheels. From the correlation of these adhesion coefficients .mu..sub.a with measured values of the drive slip .lambda..sub.a, the .mu. slip characteristic of the tires is determined and, corresponding thereto, the response slip thresholds .lambda..sub.A and .lambda..sub.B for the drive slip and the antiblocking control are set. A sliding averaging over the quotient .mu..sub.a /.lambda..sub.a of continuously determined .mu.a, .lambda..sub.a value pairs is utilized for recognizing the tire characteristic of summer/winter tires.

Method and apparatus for adapting motor vehicle drive slip threshold

A vehicle is equipped both with an anti-lock system working on the return-flow principle and with a drive-slip control device working on the differential brake principle, in which the return pump is utilized as an auxiliary pressure source for loading the driven vehicle wheels with brake pressure. In an operational situation requiring drive-slip control, a pump working at a low pressure level is actuated, even before the control responds, and conveys brake fluid both into the brake circuit of the driven vehicle wheel and into the brake circuit of the non-driven vehicle wheels, which are shut off from the brake unit of the brake system by, on one hand, an ASR-function control valve and, on the other hand, by an isolating valve. The pre-charge pump of the return pump of the brake circuits of the driven vehicle wheels is used as a low-pressure pump. This pressurization of the brake circuits with a moderate brake pressure causes a compensation of the lifting play and is utilized both for the drive-slip control and for normal braking.

Road vehicle hydraulic service-brake system and activation process

A process for compensating systematic errors of an acceleration sensor. The result of a sliding average of the output of the accelerometer, determined when acceleration in the primary measurement direction is zero, is subtracted from the output of the accelerometer thus producing a signal representative of acceleration only in the primary direction. A functional check of the accelerometer is provided by aligning the accelerometer in a second direction and comparing the acceleration measured in this second direction to the acceleration measured in the primary direction by a second device for determining acceleration and indicating a malfunction when the two measured accelerations are different and it is determined that acceleration only in the primary direction is present.

Process for compensating acceleration sensor errors

A process for anti-lock control on a racing vehicle having an aerodynamic design which results, at high speeds, in a clear increase both of the front-axle load and the rear-axle load of the vehicle. On a wheel requiring control, the response of the anti-lock control is triggered in the direction of a brake-pressure reduction when an axle-related reference quantity K.sub.h or K.sub.v, formed as a sum of weighted amounts of the wheel-circumference deceleration Z and of the brake slip of the respective vehicle wheel related to a reference speed, exceeds a threshold value. At least during the formation of the reference quantity critical for the front axle, the reciprocal value of the locking limit, determined with inclusion of negative lift forces and air resistance, of the vehicle wheels, plus a safety value .DELTA.Z.sub.o, is taken as a weighting factor X.sub.v. Within the framework of an anti-lock system suitable for carrying out the process, a brake unit switchable to different values of the brake-force distribution under the control of its electronic control unit is provided.

Process and system for anti-lock control

In a drive-slip control system (ASR) for a motor vehicle with rear-axle drive, operating on the principle of retarding again a driven vehicle wheel having a tendency to spin by activating its wheel brake, the rear-axle differential is provided with a locking device which, as the difference in the propulsive torques which can be transmitted via the driven vehicle wheels, between the latter and the roadway increases, develops an increasing degree of locking. The locking device is constructed using multi-plate clutches, which provide a frictional, limited-slip coupling between the driving ring gears and the cage of the differential on which the differential bevel gears of the differential are also mounted. In addition, the multi-plate clutches can be applied hydraulically, controlled being exercised via a solenoid valve.

Drive-slip control system

In an antilock braking system (ABS) operating on the recirculating principle with a static brake circuit and a tandem master cylinder as the brake booster, a control stage is provided in order to lessen the intensity of reaction shocks noticeable at the brake pedal when the antilock control commences. From the onset of a pressure reduction signal, the control stage generates, for at least one brake-pressure control valve of the ABS, an operating voltage for the drive motor of the recirculating pump unit which rises with increasing duration of this signal. After a predetermined rising time, the voltage can reach a maximum value, correlated with maximum speed of the motor, and then is held at this value at least until dying-out, or otherwise rises to that value which is reached within the pressure-reduction signal duration. At the dropping of the pressure reduction signal, the control stage effects a constant or stepwise reduction in the operating voltage of the motor until the motor is at a standstill, such that the time integral of the operating voltage over its reduction is greater than the time integral over the rising time of the operating voltage of the drive motor of the recirculating pump unit.

Control stage for actuation of recirculating pump unit drive motor of an

A method for correcting the rotational speeds of vehicle wheels determined by wheel sensors, a measurement of wheel speeds of the wheels of a vehicle being carried out, with specific driving conditions being that the vehicle is being neither accelerated nor braked and has no transverse acceleration. In a first part of the method, a matching of the measured wheel speeds is carried out under the specific driving conditions when the condition that the vehicle speed is below a first threshold value is satisfied. The matching of the measured wheel speeds is carried out by determining a matching factor for each of the two vehicle sides, so that, for example for the left vehicle side, matched wheel speeds are obtained from the measured wheel speeds. One of the matched wheel speeds of the left vehicle side is made equal to the associated measured wheel speed and the other of the two matched wheel speeds of the left vehicle side is obtained from the associated measured wheel by multiplying by the matchine factor of the left vehicle side, in such a way that the two matched wheel speeds of the left vehicle side assume the same value. In a second part of the method, the measured wheel speeds are balanced under the specific driving conditions when the condition that the vehicle speed is above a threshold value is satisfied. The balancing is carried out by determining a balancing factor for each wheel in relation to a reference wheel, in such a way that the balance wheel speed and the wheel speed of the reference wheel coincide with one another, and the measured wheel speeds are multiplied by the balancing factors determined in the second part of the method.

Process for correcting the rotational speeds of vehicle wheels

A steering control system executes an automatic intervention in the steering of the rear axle when a .mu.-split condition is detected, in order to stabilize the tracking of the vehicle. The steering always takes place in the direction of the vehicle side on which the higher braking torque is generated; this applies also to cornering, irrespective of whether the lower .mu.-value is on the inside of the bend or on the outside of the bend and, furthermore, irrespective of whether the vehicle is being braked or accelerated.

Steering control system for a vehicle with a steered front axle and a

An anti-blocking system for a road vehicle having a hydraulic service brake installation constructed as a dual-circuit brake installation with a front axle/rear axle brake circuit distribution which is adjustable to different values m.sub.1 and m.sub.2 of the front axle/rear axle braking force distribution, whereby the one value m.sub.1 corresponds to a braking force distribution optimized in the sense of driving stability and the other value corresponds to a relatively higher value of the rear axle braking force proportion. As long as the regulation is effective only at the rear axle, this anti-blocking system operates according to the principle of keeping a braking slippage .lambda..sub.H occurring in the rear axle brake circuit within the range of values delimited by the relation .lambda..sub.V +.DELTA..lambda..ltoreq..lambda..sub.H .ltoreq..lambda..sub.V +.DELTA..lambda. in relation to a braking slippage .lambda..sub.V occurring in the front axle brake circuit, whereby .DELTA..lambda. designates a permissive slippage differential of about 4% and .DELTA..lambda.'.apprxeq..DELTA..lambda./2. As soon as the anti-blocking regulation is also effective on the front axle, both the latter and the rear axle are regulated according to the principle of keeping both the front axle braking slippage .lambda..sub.V and the rear axle braking slippage .lambda..sub.H within the same range of values delimited by an upper limit of the braking slippage which is compatible with good braking deceleration and equally good driving stability.

Anti-blocking system for a road vehicle having a hydraulic multi-circuit

A reference signal generation circuit for providing a vehicle reference speed signal to an antilocking system in a vehicle having automatic selectable all wheel drive is provided. A reference signal generator is put into various operational states to increase, decrease or hold the reference signal in response to various operating conditions of the vehicle and the road conditions, in order to provide a more accurate vehicle reference speed signal to the antilocking control system, even when the vehicle wheels are spinning.

Control system for an automatic all wheel drive vehicle

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Fellbach, Germany

Richard Zimmer