Mazda Training manual — part 80

Dynamic Driving Safety Systems

Introduction

Introduction

•

Recent decades have witnessed an ongoing series of advances in driving safety and
comfort of automotive suspension. But ever-higher engine power and growing traffic
volume have led to an increasing demand to improve the active driving safety of
automobiles. However, a consistent stability in critical driving situations had to wait until
advent of electronic control systems.

•

The ever increasing use of electronics in vehicle systems has led to highly precise and
miniaturized sensors that can exactly detect dynamic forces created during acceleration,
deceleration, and cornering. These sensors and an appropriate electronic control system
have been the crucial prerequisite for the development of dynamic driving safety
systems that help the driver maintain vehicle control in critical driving situations.

•

Although the dynamic driving safety systems offer a huge advantage for the passenger
safety, it should be remembered that the extended driving safety does not extend the
physical limitations valid for all vehicles.

•

The following dynamic driving safety systems are used on current Mazda models and
will be described in this training manual:

–

Antilock Brake System (ABS)

–

Electronic Brakeforce Distribution (EBD)

–

Traction Control System (TCS)

–

Dynamic Stability Control (DSC)

–

Emergency Brake Assist (EBA)

•

The skills needed to diagnose and repair dynamic driving system related concerns
require comprehensive system knowledge, because any mistake can lead to
malfunctions on the brake system and consequently affect the passenger’s safety. This
course is a theoretical and practical guide to gain general and Mazda specific knowledge
about the various driving dynamics safety systems, i.e. their components, function and
diagnosis.

•

Any person involved in the diagnosis and repair of the dynamic driving safety system
must have the knowledge to deliver a “Fix it right first time” repair. The Mazda Masters
Development and Qualification path provides the following training course required for
the service on the dynamic driving safety system.

–

Dynamic Driving Safety Systems CT-L 2003

•

The ranking of this course within the Mazda Masters educational system is Level 2 –
‘Senior Technician’. It is focused on technicians who have passed the ‘Mazda
Technician’ level already.

Curriculum Training

00-1

Introduction

Dynamic Driving Safety Systems

•

The training manual “Driving Dynamic Safety Systems” is divided into the following main
chapters:

–

Introduction

–

Fundamentals

–

Antilock Brake System

–

Electronic Brakeforce Distribution

–

Traction Control System

–

Dynamic Stability Control

–

Emergency Brake Assist

NOTE: The data, tables and procedures represented in this training manual serve only as

examples. They are taken from the service literature and subjected to major or minor
changes over the course of time. To prevent any misdiagnosis always refer to the
current service literature while working on the driving dynamic safety system.

00-2 Curriculum

Training

Dynamic Driving Safety Systems

Fundamentals

Fundamentals

•

Various forces, that constantly change depending on the driving situation, determine the
driving stability of a normal passenger vehicle. Whether or not these forces are properly
transferred to the road completely depends on the four contact areas of the tyres; each
one barely the size of a postcard! The key for this transfer is the right amount and type of
friction between tyre and road surface. In the event the traction between tyre and road
surface is lost, because the affecting forces have exceeded an appropriate limit, the
vehicle handling becomes instable.

•

The dynamic driving safety systems monitor specific parameters that indicate an
impending traction loss of the wheels or vehicle skidding. In case of such situations the
respective system counteracts this development by modulating either the brake pressure
and / or the engine torque to maintain the vehicle stability.

Curriculum Training

01-1

Fundamentals

Dynamic Driving Safety Systems

Forces Acting on the Vehicle

•

A large number of forces act on a vehicle during driving. The forces most important for
understanding the dynamic driving system are shown in the illustration below.

L2003_01001

1 Yaw moment

4 Vertical force

2 Longitudinal drive force

5 Longitudinal brake force

3 Lateral

force

01-2 Curriculum

Training