Mazda Training manual - part 83

 

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Mazda Training manual - part 83

 

 

Dynamic Driving Safety Systems 

Fundamentals 

• 

Even if the vehicle does not skid, an accident may result, because it is not possible for 
the driver to steer around an obstacle with locked wheels. 

 

 

L2003_01009 

 
 
• 

The brake pressure regulation of the ABS prevents the wheels from locking-up. It applies 
the correct brake pressure to all brake callipers to maintain the vehicle’s steerability 
while simultaneously achieving a short braking distance.  

 
 

 

L2003_01010 

 
 
 

Curriculum Training 

01-11 

Fundamentals 

Dynamic Driving Safety Systems 

Electronic Brakeforce Distribution 

• 

On former vehicles, only mechanical solutions were used for brakeforce distribution 
between the front axle and the rear axle. One of the disadvantages was that, to avoid 
early wheel lock-up under all circumstances (e.g. due to wet or slippery roads), the brake 
pressure applied to the rear wheels was never optimal. 

• 

Now all Mazdas with ABS also have EBD, which allows the brakeforce distribution 
between the front and the rear axles to be adjusted based on actual conditions. 

• 

Under most conditions the proportion of the brakeforce applied to the rear wheels is 
increased, resulting in optimal vehicle stability during all conditions. This results in: 
reduced braking distance, reduced thermal stress to the front brakes, and evenly worn 
front and rear brake pads. 

• 

While a standard vehicle had a brakeforce distribution of approx. 80 % to the front 
wheels and 20 % to the rear wheels, the brakeforce distribution for vehicles with EBD 
changes up to approximately 60 % to 40 % (variable). 

01-12 Curriculum 

Training 

Dynamic Driving Safety Systems 

Fundamentals 

• 

The illustration shows the differences in applied brakeforce between a vehicle with fixed 
brakeforce distribution and with EBD. 

 

 

L2003_01011 

 

X  Brakeforce applied to the front wheels 

3  Ideal brakeforce distribution on the 

unloaded vehicle 

Y  Brakeforce applied to the rear wheels 

4  Brakeforce distribution on the unloaded 

vehicle with EBD 

1  Ideal brakeforce distribution on the fully 

loaded vehicle 

5  Brakeforce distribution with proportioning 

valve (unloaded and fully loaded) 

2  Brakeforce distribution on the fully loaded 

vehicle with EBD 

   

 

Curriculum Training 

01-13 

Fundamentals 

Dynamic Driving Safety Systems 

• 

The first portion of the illustration (areas 1 and 2) shows the range of wheel slip where 
the EBD and ABS operate. The remaining part of the illustration shows the conditions of 
less than optimal brakeforce / steerability. 

 

 

L2003_01006 

 

X  Wheel slip 

2  ABS operation range 

Y  Coefficient of dynamic friction 

3  Instable driving condition 

1  EBD operation range 

4  Locking wheel 

 
 

01-14 Curriculum 

Training 

 

 

 

 

 

 

 

Content   ..  81  82  83  84   ..