Toyota Camry Hybrid AHV40 Manual page 146

Construction and Operation of Main Components
1) Brake Actuator
a. General
D The brake actuator consists of hydraulic control and hydraulic power source portions.
D The two master cylinder pressure sensors, four wheel cylinder pressure sensors, and an accumulator
pressure sensor are installed in the brake actuator.
Hydraulic Power
Source Portion
"
Function of Main Components
Component
Master Cylinder Cut Solenoid
Valve (2-position Type)
Pressure Appliance
Solenoid Valve (Linear Type)
Pressure Reduction
Solenoid Valve (Linear Type)
Master Cylinder
Pressure Sensors
Wheel Cylinder
Pressure Sensors
Accumulator Pressure Sensor
Pump and Pump Motor
Accumulator
Relief Valve
CHASSIS - BRAKE
A
D When the brake system is started, this valve cuts the hydraulic passage
between the master cylinder and the wheel cylinder.
D When the brake system is stopped or a failure occurs in the hydraulic power
source portion, the valve opens to maintain the hydraulic passage to the
front wheel cylinders and ensure braking. However, a greater effort than
normal is required to press the brake pedal.
This valve, which is controlled by the skid control ECU, regulates the fluid
pressure from the accumulator in order to amplify the fluid pressure to the
wheel cylinder.
This valve, which is controlled by the skid control ECU, regulates the fluid
pressure in order to reduce the fluid pressure to the wheel cylinder.
The master cylinder pressure sensor converts the fluid pressure generated by
the master cylinder into electrical signals and transmits them to the skid control
ECU. Accordingly, the skid control ECU determines the braking force required
by the driver.
These sensors detect the fluid pressure that acts on the respective wheel
cylinders and transmits them to the skid control ECU in the form of feedback.
Accordingly, the skid control ECU monitors the fluid pressure of the wheel
cylinders and controls the pressure appliance solenoid valve and the pressure
reduction solenoid valve, in order to achieve the optimal wheel cylinder
pressures.
The accumulator pressure sensor constantly detects the brake fluid pressure in
the accumulator and transmits the signals to the skid control ECU.
Accordingly, the skid control ECU controls the pump motor.
Draws up the brake fluid from the reservoir tank and provides high hydraulic
pressure to the accumulator.
Stores the hydraulic pressure that was generated by the pump. The accumulator
is filled with high pressure nitrogen gas.
Returns the brake fluid to the reservoir tank to prevent excessive pressure if the
pump operates continuously due to a malfunction of the accumulator pressure
sensor.
Hydraulic Control Portion
02HCH13Y
Function
CH-45