BENDIX BA-922 COMPRESSOR Průvodce řešením problémů stáhnout pdf (Strana 7)

www.bendix.com 1-800-AIR-BRAKE (1-800-247-2725)

Air Supply

The vehicle’s compressor takes in filtered air, either at

atmospheric pressure from the outside (or already at

an increased pressure, from the engine turbocharger

in some cases), and compresses it. The compressed

air is delivered to the air dryer where water and a small

amount of oil is removed. The air then travels into the

air reservoirs (“air tanks”) - typically delivered to a

rear brake system reservoir and a front brake system

reservoir as well as any attached trailer reservoirs. For

each system, the air pressurizes the reservoir and the

air hoses all the way to the next control valve, where

the air pressure remains, ready to be used.

A vehicle may use compressed air for many tasks. Some

examples are: to provide force for braking, to deliver

air to a particular component, to off-load bulk goods,

etc.

Normal Braking

When the driver applies the foot brake, a plunger within

the foot brake valve moves, opening channels within

the valve that allow the air pressure waiting there to

pass through and be delivered to the rear and front

brake systems. The pressure quickly increases in the

brake chambers and applies force to the push rod,

transferring the force to the S-Cam or air disc brake.

(See page 22 for more about foundation brakes.)

Frictional forces slow the wheels and the vehicle comes

to a stop. When the brakes are released, the air in the

brake chambers is able to be quickly released and enable

the driver to drive away.

Vehicle Parking

Vehicles are parked using powerful springs which are

part of the spring brake assembly, to engage the brakes

and hold the vehicle in position. When the driver

prepares to move away and releases the parking brake,

the spring force is countered by the introduction of air

pressure. Anti-compounding valve features in the

system design help prevent the application of both the

spring and service brakes together.

Antilock Braking Systems (ABS)

Most commercial vehicles use electronic Antilock

Braking System (ABS) to help improve braking when

excessive wheel slip, or wheel lock-up, is detected.

Bendix

Electronic Control Units (ECUs) use patented

technology to monitor wheel speeds (on all wheels

equipped with speed sensors) and use ABS modulator

valves to adjust or pulse the braking force being applied

and released, many times per second, during an ABS

event. ABS typically improves stability and steerability,

and also reduces stopping distances on most surfaces.

In addition to the ABS features above, some recent

model ECUs have a drag torque control feature which

reduces driven-axle wheel slip (due to driveline inertia)

by communicating with the engine’s controller and

increasing the engine torque.

Antilock Traction Control

In addition to the ABS function, some Bendix ECU

models provide an Automatic Traction Control (ATC)

feature which can help improve vehicle stability and

traction during vehicle acceleration (at low speeds),

and lateral stability while driving through curves.

Electronic Stability Program (ESP

®*

)

Recent Bendix

ABS advances include ESP

which has

the ability to apply brakes to individual wheel ends, and

the trailer, to counteract the trailer “push” during

maneuvers that may lead to loss of control or jackknifes

on low to high friction surfaces (snow, rain, asphalt,

concrete, etc.)

Roll Stability Program (RSP)

The Bendix Roll Stability Program (RSP), is an all-axle

ABS solution that helps reduce vehicle speed by applying

all vehicle brakes as needed, reducing the tendency to

roll over. RSP focuses on reducing the vehicle’s speed

below the critical roll threshold during direction-

changing maneuvers such as exit ramps and obstacle

avoidance on dry, high friction surfaces.

Emergency Braking

In emergency situations where system air pressure is

reduced or lost, government regulations require

vehicles to meet specified stopping distances. As an

example, some straight truck system designs use

modulated parking-brake applications to bring the

vehicle to a stop.

Vision Systems

Bendix offers video camera systems that help drivers

back vehicles up safely, assist drivers with viewing what

is in their blind spots around their vehicles, as well as

infrared XVision

night vision camera systems that

provide drivers advanced warning of obstacles in their

pathway at night by seeing 3 to 5 times further than

their standard headlights. All of our camera systems

can be purchased individually to meet drivers’ specific

needs or can be purchased as a total system to provide

a complete 360 degree 24/7 video camera system for

drivers.

Section 1: One-Page Introduction

Introduction

*ESP is a registered trademark of Daimler Chrysler.

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