BRAKE-BOOSTER WITH COMPLEMENTARY HYDRAULIC POWER-ASSIST

A pneumatic-hydraulic hybrid pneumatic brake booster is improved. Additional hydraulic boosting (19, 20) provided by a hydraulic circuit is provided beyond a saturation point (Psat) in the operation of the pneumatic circuit. Hysteresis-induced instabilities in the pneumatic part of the booster are taken into consideration (50). A choice is made to compensate (A) for the shortfall in operation of the pneumatic circuit using the hydraulic circuit. In one example, this correction is afforded via a microprocessor which imposes a corrected process signal. Using this signal, pressure shifts in the pneumatic system are neutralized.