Mercedes-benz Aktiengesellschaft

Temic Telefunken Microelectronic Gmbh

Bernhard Topfer

Matthias Gramann

Reinhard Helldorfer

Jurgen Leuteritz

Gerhard Hettich

Wolfgang Muller

Bodo Klein

Ali Aminpour

Norman Millner

Wolfgang Scheer

A method is provided to determine an optimized value of the brake pressure ratio between a tractor and a trailer or semitrailer. In particular, an increased value of the brake pressure of the trailer or semitrailer in relation to the brake pressure resulting from the position of the brake pedal is supplied for a particular duration at the beginning of a braking operation. The increase of the brake pressure of the trailer or semitrailer takes place as a function of the brake pressure, p.sub.Anh, resulting from the position of the brake pedal. In braking operations when a tractor is travelling without a trailer or semitrailer, an allocation of the achieved deceleration, z.sub.ist, to the brake pressure p.sub.Zug of the tractor is stored as a function of the load state of the tractor. When the tractor is travelling with a trailer or semitrailer, a brake pressure is supplied for the trailer or semitrailer and is allocated to the brake pressure of the tractor such that, in subsequent braking operations, the actual value of the deceleration which is then set at a prevailing brake pressure of the tractor, giving due regard to the load state of the tractor, corresponds to the value, derived from the stored allocation, of the deceleration achieved without a trailer or semitrailer at the same brake pressure of the tractor.

Method of determining an optimized value of brake pressure ratio between

A method is described for determining the wheel speed during braking of a vehicle having in addition to at least one wheel with speed sensor at least one further wheel without speed sensor and means for determining the braking pressure. For this purpose, the braking operation is subdivided into several time intervals during which the relative value from the braking energy and the kinetic energy of the vehicle are obtained, and the contribution of the wheels without speed sensors to the braking energy is defined during a first time interval. Furthermore, the ratio of the relative value in this time interval to the relative values in further time intervals is formed, and the mean value for the wheel speed of all wheels without speed sensors is ascertained in the further time intervals from the ratio of the relative values.

Method for determination of wheel speed

A method is described for determining brake coefficients, which define the relationship between the brake pressure and the brake force at a wheel or axle of a motor vehicle or of a section of a vehicle combination during the braking operation of the vehicle or vehicle combination. During the braking operation of vehicle, the wheel speed and the brake pressure are determined measurement/time intervals with differing brake pressure distribution between the wheels, axles or vehicle sections are formed, in which the equilibrium of forces between the brake force and the force of inertia of the motor vehicle is obtained. The mass-related brake coefficients of the brake-pressure-sensed wheels or axles and a mean value for the mass-related brake coefficient of all non-brake-pressure-sensed wheels or axles are determined from the equations for the equilibrium of forces in the measurement/time intervals; by forming the quotient between these mass-related brake coefficients, the relative brake force development of the individual axle (or of the individual section of the vehicle combination), i.e. its respective proportion of the total brake force sum, can be determined without the need to know vehicle-specific design data or the total mass.

Method for controlling a braking operation including determining brake

A brake pressure regulation method and system for a trailer vehicle, which is connected to a tractor vehicle having an electronically controlled pressure-medium brake renders sensing of the forces between the tractor and the trailer vehicle and, to this extent, also a corresponding force-recording apparatus superfluous. The method can be used advantageously in tractor vehicles equipped with an ABS. The method is based on transmission of wheel speed signals from the trailer vehicle to the tractor vehicle and brings about an adjustment of the brake pressure relation between the tractor and the trailer vehicle to the same average speed of the wheels of non-driven axles of the vehicle by correcting the brake pressure for the trailer vehicle adaptively to give braking work which can be distributed in optimum fashion to the tractor vehicle and the trailer vehicle. Since, in this way, the average utilization of adhesion at braked wheels of the trailer vehicle is the same as that at the non-driven, braked wheels of the tractor vehicle, not only is an increase in directional stability during braking achieved but also an advantageous evenness of the brake lining wear on the tractor vehicle and the trailer vehicle. The method can also be carried out very advantageously in conjunction with electronically controlled pressure-medium ABS brake systems for trailer vehicles.

Tractor/trailer brake pressure regulation method and system

A method utilizes components of an existing anti-lock brake system (ABS) in order thereby to achieve an automatically self-optimizing inter-axle brake-pressure distribution acting far below the wheel lock limit. For this purpose, the brake pressure and, hence, the brake-force distribution are regulated axle-specifically far below the wheel lock limit too. An immediate dynamic intervention is, on one hand, effected in the case of sufficiently large wheel-speed differences between the axles. On the other hand, an adaptive predetermination of correct brake-force distributions is made the basis for each current regulating intervention. Even before the occurrence of large speed differences, the brake-force distribution expedient in each case for these is here predictively determined, stored, and, if required, correspondingly adapted to current requirements, i.e. corrected, in the course of subsequent dynamic braking demands. Requisite determination parameters are obtained for each journey either via characteristic diagrams specific to the family of vehicles or are determined individually on the individual vehicle by a learning approximation routine.

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Stuttgart, Germany

Bernhard Topfer