Vehicle brake system and method of detecting piston location of a plunger assembly

A method of determining a homing position of a piston within a plunger assembly for a vehicle brake system at the beginning of an ignition cycle of the vehicle, the method comprising:

• (a) providing a plunger assembly having a housing defining a bore therein, wherein the plunger assembly includes a piston slidably disposed in the bore for pressurizing fluid within a pressure chamber when the piston is moved in a first direction, and wherein the plunger assembly further includes an electrically operated linear actuator for moving the piston within the bore;
• (b) providing electrical power to the linear actuator of the plunger assembly;
• (c) actuating the linear actuator to retract the piston in a second direction opposite the first direction towards an end stop;
• (d) detecting the piston engaging with the end stop;
• and
• (e) subsequently to step (d), actuating the linear actuator to stop movement of the piston.

A method of detecting the position of a piston relative to a compensation port and seal configuration of a plunger assembly, the method comprising:

• (a) providing a fluid reservoir;
• (b) providing a plunger assembly having a housing defining a bore therein, wherein the plunger assembly includes a piston slidably disposed in the bore for pressurizing fluid within a pressure chamber when the piston is moved in a first direction by a linear actuator, and wherein the plunger assembly includes a port in fluid communication with the fluid reservoir and with the pressure chamber when the piston is in a first position, and wherein the port is prevented from being in fluid communication with the pressure chamber when the piston is in a second position caused by the spacial relationship between a seal and the port within the housing of the plunger assembly;
• (c) positioning the piston in a retracted position;
• and
• (d) measuring the difference between the retracted position of the piston and a linear zero position of the piston wherein the port is positioned adjacent the seal by a relatively small distance such that the port is in fluid communication with the fluid reservoir and with the pressure chamber.