Abs-Specific Brake Power-Assist Units 845106

For some time now, a number of anti-skid brake systems have been on the market which are characterized by their location between the master cylinder and the wheel brakes, and separate from the brake power-assist unit. At the present time, integrated systems are being prepared for introduction. In these systems, the hydraulic brake power-assist unit takes over both power-boost and ABS pressure-modulation. The various concepts regarding ABS-integrated brake power-assist units exhibit considerable differences in their pedal characteristics when the ABS function comes into operation, and with respect to the possibility of improving the behavior of conventional brake systems.
It is the object of this article to present the various types of ABS pressure-modulation in combination with brake power-assist units, and to emphasize the advantages and disadvantages of the individual concepts. In addition to the constructional outlay involved, the aspects regarding anthropotechnical safety are taken into consideration as criteria when the asessment is made.
The braking behavior during partial and panic braking in cooperation with the anti-skid system is described with the aid of curves demonstrating pedal force against pedal travel. These curves show clearly how similarly, or how differently, the brake pedal feels when the brakes are applied with, and without, ABS. With this information, it is possible to draw conclusions on the quality of the brake systems ability to adapt to the driver.
Using elementary diagrams, the hydraulic systems for the various brake power-assist units with ABS are demonstrated.


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