BENDIX MC-12 MODULATOR CONTROLLER ASSY Průvodce řešením problémů stáhnout pdf (Strana 7)

More info: visit www.bendix.com 1-800-AIR-BRAKE (1-800-247-2725)

Air Supply

The vehicle’s compressor takes in ﬁ ltered air, either

at atmospheric pressure from the outside or already

at an increased pressure (e.g. from the engine

turbocharger), 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 19 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 vehicle 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. An anti-compounding valve in the

system design helps 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. These valves operate 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 advanced

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.

Electronic Stability Program

The ESP

* functionality of the Bendix Advanced ABS

system responds to a wide range of low- to high-

friction surface scenarios including rollover, jackknife

and loss of control. It is the recommended system for

all power vehicles and especially critical for tractors

pulling trailers.

In the case of vehicle slide (over-steer or under-steer

situations), the system will remove the throttle and then

brake one or more of the “four corners of vehicle” (in

addition to potentially braking the trailer), thus applying

a counter-force to better align the vehicle with an

appropriate path of travel. For example, in an over-

steer situation, the system applies the “outside” front

brake; while in an under-steer situation, the “inside”

rear brake is applied.

In the case of a potential roll event, the system will

remove the throttle and quickly apply the brakes to

slow the vehicle combination below the threshold.

Adaptive Cruise & Braking (ACB)

The Bendix

Wingman

™

ACB system provides cruise

control and a monitoring system to assist and/or

alert the driver. In addition, ACB tracks the vehicles

ahead and helps maintain a pre-set following interval.

The technology builds on the Bendix

ESP

stability

system.

Emergency Braking

In emergency situations where system air pressure

is reduced or lost, government regulations require

vehicles to meet speciﬁ ed stopping distances. As

an example, some straight truck system designs use

modulated parking-brake applications to bring the

vehicle to a stop.

Section 1: An Overview

Introduction

*ESP is a registered trademark of Daimler and is used by BCVS under license.

1 2 3 4 5 6 7 8 9 10 11 12 ... 69 70

Komentáře k této Příručce

Žádné komentáře

BENDIX MC-12 MODULATOR CONTROLLER ASSY Průvodce řešením problémů Strana 7

Komentáře k této Příručce

Související produkty a manuály pro Modulátor BENDIX MC-12 MODULATOR CONTROLLER ASSY