Abstract: The subject invention provides a master cylinder having a compact profile. In particular, the master cylinder comprises a hollow body having a continuous outer wall with a continuous thickness. An end wall is integrally formed with the outer wall at a first end to close an end of an integrally formed bore. A number of apertures are formed within the outer wall to provide fluid communication between the outer wall and the bore. A flange is also integrally formed with the outer wall at a second end to define a fully integrated master cylinder. The outer wall further includes thickened sections extending between an inner surface of the bore and a mounting surface with the thickened sections being at least 30 percent smaller than the inner diameter of the bore for providing the compact profile of the integrated master cylinder.

Abstract: The subject invention provides a master cylinder having a compact profile. In particular, the master cylinder comprises a hollow body having a continuous outer wall with a continuous thickness. An end wall is integrally formed with the outer wall at a first end to close an end of an integrally formed bore. A number of apertures are formed within the outer wall to provide fluid communication between the outer wall and the bore. A flange is also integrally formed with the outer wall at a second end to define a fully integrated master cylinder. The outer wall further includes thickened sections extending between an inner surface of the bore and a mounting surface with the thickened sections being at least 30 percent smaller than the inner diameter of the bore for providing the compact profile of the integrated master cylinder.

Abstract: A vehicle braking system has a self-apply control which is effective to control the vehicle wheels under braking situations, traction control situations and chassis control situations. The self-apply control includes an electronic control unit (ECU) to establish the operation of the brakes. A positive displacement pump is utilized to provide fluid during self-apply operation. The output pressure of the pump is controlled by a variable pressure isolation valve which is controlled by the ECU to establish the maximum pressure required during each situation such that excess fluid pressure is not generated at the pump. the isolation valve has a stepped diameter bore in which a valve spool is disposed. The valve spool and the bore cooperate to form a unique dampening structure. The valve land and the bore wall form a flow restriction to and from a dampening chamber formed by the bore step and the valve land.

Abstract: The solenoid control valves of a solenoid-operated automotive antilock braking system are cyclically controlled to enable the valves to operate in a stable, partially open position that provides a desired fluid flow while minimizing noise associated with acceleration and deceleration of the controlled fluid. After an incipient lock-up condition is detected and the solenoid valve has been energized to hold and/or permit a partial release of the brake pressure, the solenoid is initially de-energized for a defined interval designed to reduce the current to a scheduled value. In this interval, the solenoid current is re-circulated through a free-wheeling diode for a smooth decay, allowing the valve to slowly open in a smooth and stable fashion. Then the solenoid is pulse-width modulated (PWM) at a frequency and duty cycle designed to maintain the solenoid current at the scheduled value. The interval of PWM is relatively brief to avoid any instability associated with the current pulsation.

Abstract: A brake system control apparatus comprising: a fluid brake system including a master cylinder containing a hydraulic fluid having a hydraulic pressure, a hydraulic pump having an output hydraulically coupled to the master cylinder, a motor coupled to and providing motive force to the hydraulic pump, a current sensing device coupled to the motor and providing an output signal indicative of electric current through the motor; and an electronic controller coupled to the current sensing device comprising a first sampler taking a first sample of the output signal a first time period after a start up of the motor, a second sampler taking a second sample of the output current a second time period after start up of the motor and a divider for determining a ratio of the first and second samples wherein the ratio is indicative of a hydraulic pressure in the master cylinder at the start up of the motor.

Abstract: A solenoid driver circuit is provided that operates a solenoid in a quiet operation by reducing solenoid armature velocity. A pulse signal and a ramp signal are provided by a frequency generator and a ramp generator, respectively. A frequency switching circuit receives the pulse and ramp signals and responsively provides a time varying pulse signal that has a duty cycle that decreases with time. A dwell circuit allows the frequency switching circuit to control the solenoid for a first time period and then provides an on signal to the solenoid, maintaining the solenoid in the on position. The solenoid driver circuit is particularly suitable for use with solenoid controlled valves.