Daimler-benz Ag

Mercedes-benz Aktiengesellschaft

Dailmer-benz Aktiengesellschaft

Manfred H Burckhardt

Richard Zimmer

Franz Brugger

Sinan Kazan

Rainer Freitag

Hellmut Krohn

Horst Grossner

Reinhold Schoeb

Armin Mueller

Gerd Eilert

Andreas Faulhaber

Rainer Spiecker

Heinz Leiber

Paul Schwerdt

Armin Muller

Martin Klarer

Walter Kostelezky

Jurgen Paul

Erich Waxenberger

Werner Schneider

Hans-Jorg Florus

Walter Lutze

Siegfried Schlosser

J/u/ Rgen Paul

Friedrich Solleder

Herbert Schulte

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

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

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

In a drive slip control device for a road vehicle, which is provided with an anti-lock system operating on the pump-back principle and having a return pump of the anti-lock system associated with the brake circuit of the driven vehicle wheels used as the auxiliary pressure source for the drive slip control, for braking a vehicle wheel tending to spin. When the drive slip control is activated, the main brake pipe of the brake circuit of the driven vehicle wheels is shut off from the brake unit by means of a drive slip control valve. The return pump is activated and is shut off from the brake unit until the drive slip of one of the driven vehicle wheels exceeds a threshold value whose magnitude lies between the drive slip required value and threshold response value. The brake pressure control valves of the brake circuit of the driven vehicle wheels are driven into their closed position by means of this anticipatory activation of the return pump. This causes high pressure to build up in the main brake pipe, which is limited to a value of the anti-lock braking system and of the brake equipment by means of a pressure limiting valve, which is then available for an introductory brake pressure build-up phase of the drive slip control on the vehicle wheel requiring it. An additional outlet valve, by means of which the return line of the rear axle of the anti-lock system can be directly connected to the brake fluid reservoir, can be provided for controlling the pressure reduction phases.

Drive slip control device

An anti-lock brake system (ABS) for a road vehicle is equipped with a wheel slip control system (ASR) and a hydraulic dual circuit brake system having front axle/rear axle brake static brake circuits, one brake circuit being allocated to the driven (rear) wheels of the vehicle and one to the non-driven (front) wheels. The system has two high-pressure pumps, one for each of the two brake circuits and which, in control phases of the ABS, brake fluid can be fed into the output pressure spaces of the brake unit and wherein the high-pressure pump allocated to the rear axle brake circuit is also utilized as auxiliary pressure source for the ASR. At the front axle brake circuit, the ABS operates on the feedback principle and at the rear axle brake circuit it operates on the discharge principle.

Anti-lock brake system

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

In a hydraulic dual-circuit brake system for motor vehicles, especially high-powered heavy passenger cars, in which the front wheel brakes combined in a front-axle brake circuit are exposed to higher thermal loads than the rearward brakes, brake fluid is conveyed by means of a feed pump to the outlet-pressure space for cooling the front wheel brakes following a braking phase. Circulated brake fluid flows from the master cylinder outlet pressure space assigned to the front-axle circuit, to the wheel brake cylinders, to an additional functional space of the primary piston in the master cylinder, and back to the supply vessel. The circulating fluid pump is controlled by a timing relay which is tripped by the brake-light switch and remains energized for a predetermined time interval to allow sufficient cooling by fluid circulation.

Cooled hydraulic high-performance brake system for motor vehicles

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

An anti-locking system is provided for a two-wheel road vehicle which is equipped with electro-hydraulic braking pressure control equipment, which generates the driving signals necessary for appropriate driving or braking pressure control valves by processing wheel rotational speed sensor output signals. In order to obtain both good braking effect and good driving stability when the control equipment responds, the brake slip .lambda..sub.F of the front wheel is controlled to a value which is always less than the rear wheel brake slip .lambda..sub.R. The control responds if, on the one hand, critical values of the wheel deceleration are exceeded and/or, on the other hand, if the brake slip .lambda..sub.F on the front wheel exceeds a threshold value still considered as permissible. As part of the anti-locking system, the braking installation is so designed that for both manual actuation and pedal actuation both wheel brake circuits respond with the installed braking force distribution. This is so arranged that for adhesion coefficients of more than 0.3 between the track and the wheel, the rear wheel would lock before the front wheel should the control equipment not operate.

Anti-locking system for a two-wheel road vehicle with hydraulic dual

In a vehicle equipped with a propulsion control system combined with an anti-blocking system, a pressure reservoir provided as a brake pressure supply-source which can be charged by means of the return pump of the anti-blocking system, whereby the charging operation is valve-controlled so that the feed from the return pump is directed into the pressure reservoir during pressure-reduction phases of the propulsion control system, the pressure reservoir can also be charged, outside the control phases of the propulsion control system, either by operating the driver's brake pedal or by automatic activation of a charging circuit accompanied by the operation of the return pump.

Installation for charging a pressure reservoir provided as a pressure

A device for cooling the wheels of motor vehicles which are equipped with disc brakes mounted on the wheels between the wheel centers and a cover plate. The rotors of the disc brakes are fastened to the wheel flange of the wheel hub by a pot-shaped part which delimits radially an annular space opening in the direction of the cover plate. The cover plate is provided with openings through which a cooling air stream can enter the wheel space containing the brake. The wheel center is provided with openings near a rim portion thereof through which air can escape from the outer annular space left between the brake and wheel center. The annular space communicates through a space between the rim and the brake with an annular space delimited by the remaining space and the cover plate in the axial direction. A jacket of the pot-shaped mounting part, by which an inner hub side annular space is delimited in the radial direction from the outer annular space, is provided with overflow openings disposed around a circumference of the jacket.

Device for cooling motor vehicle wheels

A system for controlling the propulsion on motor vehicles which not only enables the output torque of the drive unit of the vehicle to be utilized in an optimum manner in critical driving situations, especially under extreme road conditions, but also endows the vehicle with good stability and enhanced driving safety. A comparator is provided, in a propulsion control system which is triggered by at least one presettable or permanently preset threshold value of the speed of the vehicle, and generating an output signal causing the drive torque to be reduced, as soon as this threshold value is exceeded and a signal is present, which indicates that an individual wheel brake is being activated and/or that one of the driven wheels is tending to spin. The threshold value of the speed of the vehicle, which value governs the control process, is preferably regulated in accordance with the transverse acceleration which acts on the vehicle whenever it follows a curved path.

System for controlling the propulsion on motor vehicles

A drive control device for a motor vehicle with rear axle drive and equipped with an anti-blocking system. As part of a rotational speed sensor arrangement provided to determine the state of movement of the vehicle wheels, each of the non-driving front wheels has an associated rotational speed sensor and the two rear wheels have a common rotational speed sensor, which measures the rotational speed of the propeller shaft in the transmission system. A hydraulic actuator provided for brake pressure control corresponds in construction to that of a 4 channel anti-blocking system. These components are utilized for both the drive control and the anti-blocking control. An electronic control system of the drive control device, which processes the output signals of the rotational speed sensors, initially activates the right-hand rear wheel brake, as soon as a driving wheel starts to spin. If the vehicle does not accelerate in consequence or if, indeed, there is a deceleration of the vehicle, switching occurs to the left-hand driving wheel brake either with a time delay or immediately. If necessary, both driving wheel brakes are activated with a time delay and the engine torque withdrawn. In the case of travel around a curve, the control cycle is introduced by braking the driving wheel on the inside of the curve.

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Waiblingen, Germany

Manfred H Burckhardt