Contents: Electronic dual-circuit pump doses… ↳ HECU controls ABS functions ↳ EBD limits rear wheel slip ↳ BTCS is active up to 50 km/h ↳ ESP automatically applies the brakes… ↳
The Focus brake system control elements are installed under the hood: 1 - expansion tank with brake fluid; 2 - active brake booster with integrated brake master cylinder, 3 - ABS control module.
The Road and Street Regulations (StVZO) require two braking systems (foot brake and parking brake) to operate independently of each other. The reason: if one brake system fails, the other still brakes with reduced power. The service brake in your Focus is additionally divided diagonally - each brake circuit acts on one front wheel and one opposite rear wheel: if one circuit fails, one front wheel and one rear wheel of the other circuit remain fully functional. With only one working brake circuit, your Focus brakes significantly more slowly, but still stops. You will notice the failure of one circuit not only by the increased braking distance, but also by the increased travel of the brake pedal and by the lit indicator light on the dashboard.
Anti-lock braking system (ABS), traction control system (BTCS), electronic brake-force distribution (EBD), electronic stability program (ESP).
ABS and BTCS enhance active driving safety. EBD replaces the mechanical brake force regulator. The ABS function ensures full control even under full braking. BTCS improves directional stability when accelerating on slippery roads. As another active safety element, Electronic Brake-force Distribution (EBD) is becoming increasingly common in modern compact cars. EBD is activated before ABS and improves braking stability by precisely electronically regulating the slip of the rear wheels. The anti-lock braking system used in the Focus contains an electronic and hydraulic control module (HECU). Both systems are housed in a common aluminum housing. To accurately determine the number of wheel revolutions, the HECU uses one sensor on each wheel: EBD and BTCS use the same signals. HECU works with eight solenoids, a hydraulic pump driven by a DC electric motor and two vacuum manifolds. In the Focus, the wheels are adjusted individually up to a speed of 120 km/h. On the rear axle, this is done in parallel: the model is the wheel that first tends to lock. In case of system errors, ABS. EBD and BTCS are switched off - in this case, the brakes work without electronic support, like a conventional braking system. The malfunction can be identified by the ABS warning light: it does not go out after the mandatory self-test. ABS in Focus is fully diagnosed. Error codes are archived in a permanent memory device. In addition, Ford supplies all Focus models with a petrol engine from 1.6 l with ESP in a special configuration.
Electronic dual-circuit pump doses braking power
Braking energy is distributed in the system by an electronic dual-circuit pump. Each of the four individual control channels has a pair of electromagnetic valves (one inlet and one outlet). The inlet valves are normally open and have a switchable orifice (a small orifice for fine adjustment of the passage of a small amount when the brakes are activated, a large orifice for minimal flow resistance during normal braking function).
HECU controls ABS functions
The HECU controls the ABS functions, calculates the driving speed based on the signals from the wheel speed sensors, monitors all electrical components and stores data on malfunctions. When the ignition is on, the system carries out a self-test called by the HECU before driving. During driving, the electrical connections are constantly monitored. This includes a polarity check, as well as a check for short circuits and conductivity faults. The solenoid valves are also regularly checked to monitor the ABS function, for which the system sends a test pulse. Possible malfunctions are quickly and specifically read by your Ford dealer with the FDS 2000 control device.
EBD limits rear wheel slip
EBD constantly compares the slip of the front and rear wheels and doses or distributes the braking force accordingly. Usually, the operation of EBD is not felt, its technology implements - regardless of the vehicle load state - minimal braking distances. In addition, EBD replaces the traditional brake force regulator in the system.
BTCS is active up to 50 km/h
BTCS is integrated into the Focus ABS with two shut-off solenoid valves and two hydraulic inlet valves. The system is activated as needed at speeds of up to 50 km/h. It remains active as long as required for starting off and accelerating on slippery roads. BTCS ensures good traction of the front wheels. This also improves steering quality during gentle acceleration from a standstill and especially during cornering maneuvers. If BTCS detects slippage of one front wheel, it is automatically braked until the rotating wheel has regained traction.
ESP automatically applies the brakes to individual wheels
ESP stabilizes driving characteristics in the borderline ranges of driving dynamics. The system supports the driver in the desire to more reliably keep the car on course by targeted intervention in the braking of individual wheels or by adjusting the engine control. But despite all theoretical considerations about absolute driving safety, ESP cannot eliminate the limits of driving physics: where the brain initially does not work, even the most modern chassis electronics will not help.
The article was taken in its entirety from the specified website [Fordbook.ru]