Enhanced pneumatic brake system

Abstract

In a brake system (10) having a fluid pressure servomotor (12) with a housing having an operational chamber (30) connected to an intake manifold (102) of a vehicle and a control chamber (32) connected to an accumulator (50). A wall (28) which separates the operational chamber (30) from the control chamber (32) carries a valve (38) connected to receive an input from an operator by way of pedal (20). In the rest position, the valve (38) allows the vacuum created at the intake manifold (102) to evacuate air from the operational chamber (30) and control chamber (32). When an operator desires to effect a brake application, an input force applied to the valve (38) by way of pedal (20) allows air from the accumulator (50) to be communicated to the control chamber (32) and create a pressure differential across the wall (28). The pressure differential moves the wall (28) to produce an output force to pressurize fluid in a master cylinder (14) which is communicated to the individual wheel brakes (16, 18) to complete a brake application. The air supplied to the control chamber (32) from the accumulator (50) has been heated to a predetermined temperature to increase the pressure therein above atmospheric pressure enhance the development of the pressure differential.