Mercedes-benz Aktiengesellschaft

Daimler Chrysler Ag

Daimler-benz Ag

Bernd Knoff

Manfred Steiner

Albrecht Eckl

Franz Brugger

Wolfgang Kiesewetter

Martin Klarer

Alexander Fuchs

Siegfried Rump

Lorenz Maack

Eberhard Pfeifle

Carsten Lauer

Joachim Nell

Hans-Georg Riedel

Christoph Steffi

Brian Douglas

Walter Klinkner

Henning Wallentowitz

Karl-Heinz Richter

Peter Herges

Johannes Clauss

Rudolf Hoernig

Manfred F Brugger

Fredy Eckstein

Ulrich Stoll

Dieter Neugebauer

Karl-Heinz Buechle

In a power steering device comprising a power steering pump, and to a method for operating a power steering device for a vehicle comprising a hydraulic circuit provided with a rotary slide valve, a steering cylinder and a control valve for adjusting the volume flow of a hydraulic medium as required for steering assistance, the control valve is arranged on the pressure side of the pump in such a way that it divides the volume flow (Q) from the power steering pump into at least a first base partial flow (A) and a second controlled partial flow (B), the base partial flow (A) being independent from the operating state of the control valve and always available for steering assistance, whereas the partial flow (B) is dependent on the operating state of the control valve.

Power steering device for a vehicle

A brake system for a vehicle is equipped with a brake servo assistance unit for the automatic generation of brake force and with at least one sensor for the generation of a measuring signal. This signal represents an activity on the part of the driver and can be fed to a brake pressure control unit. An activation control signal for the actuation of the brake servo assistance unit can be generated should the measuring signal lie within an activation value range. In order to improve operating reliability, at least two sensors are provided for measurement of an activity on the part of the driver, and an activation control signal can be generated should the measuring signals from the sensors each exceed a reference value.

Brake system for a motor vehicle

In a method for carrying out an automatic braking operation in a vehicle, a stte variable for describing driver's reactions and/or events outside the vehicle is sensed by means of a sensor, compared with a reference value and, when the reference value is exceeded, a higher braking pressure than the braking pressure corresponding to the brake pedal position is generated. In order to increase reliability, the automatic generation of braking pressure is suspended for a specific holding time if the state variable which is sensed by sensor means lies outside an acceptable tolerance range.

Method for automatic braking of a vehicle

A method for determining an initiation threshold value for an automatic braking process, in which an automatic braking process is used and a brake pressure is produced which is greater than the brake pressure which corresponds to the operation of the brake pedal by the driver. Short distances between vehicles increase the risk of accidents. If a driver operates the brakes when there is a short distance between the vehicle and the preceding vehicle, in the vast majority of cases, the driver of the following vehicle is often required to perform an emergency braking due to the short distance between the vehicles. To improve the safety of vehicles, an emergency braking is performed, as quickly as possible, when the distance between vehicles is short. This emergency braking, within what is physically possible, ensures rapid deceleration of the vehicle and thus helps to avoid rear-impact accidents. While performing the automatic braking process, the method incorporates a reduction of the initiation threshold value if it is determined that the distance to a preceding vehicle is less than a predetermined limit.

Method for determining an initiation threshold value for an automatic braking process

A process and device are disclosed for preventing a vehicle from colliding with an obstacle during parking. The object of the invention is therefore to ensure that a collision can be reliably avoided without any additional intervention of the drive. In a device with at least one sensor for generating signals which represent the distance between the vehicle and an obstacle, the signals are processed in an evaluation unit. When at least one distance-representing signal falls below a limit value, a warning signal is generated. This warning signal drives a control valve which generates a pressure difference between the working chamber and the vacuum chamber in a brake booster when the warning signal is generated. This pressure difference causes the braking pressure to rise in the wheel brake cylinder and therefore slows the vehicle down to a standstill.

Preventing the collision of a vehicle with an obstacle

An automatic braking operation is triggered before the operation of the brake pedal if, as the required criterion, the operating speed exceeds a triggering threshold value when the gas pedal is released. The triggering threshold value is adapted to the driver's actions to achieve a more reliable separation between necessary and unnecessary triggerings of the automatic braking operation. At least one magnitude is detected which represents the driver's actions and, on the basis of this magnitude, the triggering threshold value for the automatic braking operation is determined. It is thus unimportant whether the required criterion for the triggering of the automatic braking operation is sufficient or whether additional criteria are required for this purpose, such as the determination of a transfer of the driver's foot from the gas pedal to the brake pedal.

Method for determining a triggering threshold value for an automatic braking operation

A process carries out an automatic braking operation in which, when the return speed of the accelerator pedal exceeds a threshold value and a transfer of the driver's foot from the accelerator pedal to the brake pedal is determined, an automatic braking operation is triggered. During that operation, a brake pressure is generated in the wheel brakes and is terminated when either a defined time has been exceeded since the triggering of the braking operation or when an operation of the brake pedal takes place by the driver. A support of the driver is ensured when operating the brake pedal in critical driving situations and a brake pressure buildup is carried out even before the operation of the brake pedal by the driver. After the automatic braking operation has been triggered, monitoring occurs to determine whether the time derivation of a quantity representing the operation of the brake pedal exceeds a threshold rise value. In such event, exceeding of the threshold rise value must take place within a defined time period after the triggering of the automatic braking operation, whereby the automatic braking operation is continued.

Process for carrying out an automatic braking operation

The invention provides a method for determining a threshold value for triggering an automatic brake application wherein a braking pressure greater than that corresponding to the position of the brake pedal is developed when the actuating speed of the brake pedal exceeds a triggering threshold value determined from a preset threshold value and a vehicle-specific correction factor. According to the invention, a standard curve is stored representing the relationship between the vehicle deceleration and the pedal travel, said standard curve having a pedal travel value sP0 for a vehicle deceleration aFZG0=0 m/s.sup.2. During a brake application, pairs of values for pedal travel and vehicle deceleration are determined several times, with a pedal travel value sPi0 being determined for a vehicle deceleration of 0 M/s.sup.2 corresponding to each value pair, based on a curve that is the same as the standard curve. A sliding average sPm is then calculated from the values of sPi0 obtained, and the relative deviation ABW=sPm/sP0 is then determined from the value sP0 as a vehicle-specific correction factor ABW. The triggering threshold value is then determined as a function of the product of the preset threshold value VS and the vehicle-specific correction factor ABW.

Method for determining a triggering threshold value for an automatic

The invention relates to a method for setting a trigger threshold value for an automatic braking operation. When the actuating speed of the brake pedal exceeds a threshold value, automatic braking operation is initiated, and a brake pressure is increased relative to the brake pressure corresponding to the position of the brake pedal. During each brake actuation a relation is formed between the pedal travel of the brake pedal and the derivative of the vehicle deceleration with respect to the pedal travel. A correcting value is defined from this relationship and the threshold value for automatic braking is determined as a function of a preset threshold value and the correcting value.

Method for determining a trigger threshold value for an automatic

A method checks a vehicle brake system rapidly and reproducibly to measure the correlation between the brake pedal travel and the retardation produced. A test-bed routine is called up in the control unit. During the operation of the test-bed routine, the functioning of the brake system is checked. For this purpose, a pressure difference is produced in the vacuum brake booster. The brake booster pressure difference produces a brake pressure in the brake master cylinder, and a pedal travel corresponding to this brake pressure simultaneously arises. The retardation can either be measured at the rollers of the test bed or is derived from continuously measured wheel speed values. A retardation value can be determined for each wheel as can a correlation between the pedal travel and the retardation from the measured values in the presence of different brake booster pressure difference. The process can average the values measured at the individual wheels.

Vehicle brake system checking method

In an automatic braking procedure which can be terminated whenever the brake pedal is moved in the direction of its rest position, a braking pressure which is higher than would correspond to the pedal position of the brake pedal is generated where it is established by a triggering criterion that an emergency braking is in force. The invention ensures that an automatic braking procedure can always be aborted by the driver by the fact that, on the belt lock of the safety belt for the driver, a switching element is actuated when the locking tongue of the safety belt is engaged in the belt lock. It is thereby established whether the driver is belted-up. If the driver is not belted-up, then the execution of the automatic braking procedure is suppressed. An automatic braking procedure can only take place if the driver is belted-up. If high deceleration forces occur, then the driver is held by the safety belt and does not have to brace himself or herself. Thus, the driver can always terminate the braking procedure which is particularly necessary when the driver actuates a control pedal in a predefined manner, as constituted by the actuation of the brake pedal in the direction of its rest position--i.e. a releasing of the brake.

Automatic braking termination arrangement having a switching element

The invention relates to a method for determining the start of an automatic braking process. In those instances where the brake pedal is actuated starting from an initially unactuated position, triggering of automatic braking occurs when the actuation speed of the brake pedal remains above a threshold trigger value for automatic braking, and a prescribed pedal travel is exceeded in a specific time interval after the start of the actuation of the brake pedal. Light depression of the brake pedal which takes place only briefly at a high pedal actuation speed does not lead to the automatic braking process being triggered.

Method for determining the start of an automatic braking process

The invention relates to a method for defining the initiation sensitivity of an automatic braking procedure, in which method the threshold value for the initiation of an automatic braking procedure is reduced as a function of the pedal distance which has been traversed. The object of the invention is to ensure that in the event of actuation of the brake shortly after the automatic braking procedure has terminated, the automatic braking procedure is again initiated rapidly and easily. For this purpose, the initiation threshold value for the automatic braking procedure is reduced within a time period after the satisfaction of the interruption criterion.

Method for controlling the initiation sensitivity of an automatic

The invention relates to a method for carrying out an automatic braking process for motor vehicles with an anti-lock brake system. An automatic braking process is triggered when it is detected by the anti-lock brake system that at least one wheel of an axle of the vehicle reaches the locking limit. The brake pressure for the axle of this wheel starts to be controlled by the anti-lock brake system. However, a further increase in brake pressure at the wheels of the other axles of the vehicle is possible since, because of the load distribution of the vehicle and because of the distribution of braking force, the locking limit of the said wheels is not yet reached. According to the invention, a further increase in the brake pressure at the other axles takes place during the automatic braking process.

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Esslingen, Germany

Bernd Knoff