Brake vacuum booster characteristics are of great importance to understanding overall brake system operation in light vehicles so equipped. In recent years, engineering reports relevant to traffic crash reconstruction have discussed, among related areas, the effective gain of brake booster systems at high applied brake pedal force levels and with various levels of vacuum available within the booster. A vehicle-testing framework is presented for characterizing and understanding effective gain with pedal forces ranging above the runout point of a vacuum booster, as well as booster operation relative to varying levels of available vacuum and patterns of depletion of stored vacuum. Measurements are reported for a variety of example vehicles. The objective of this paper is to promote improved understanding of brake booster operation and to advance more careful articulation of brake booster topics within the reconstruction community.
James Walker, Robert Rucoba, Dan Barnes, Steven Kent