Mazda Training manual - part 84

 

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Mazda Training manual - part 84

 

 

Dynamic Driving Safety Systems 

Fundamentals 

Traction Control System 

• 

Critical driving situations can occur not only during braking, but also while driving, 
cornering, starting off, and accelerating (especially on wet or slippery roads). These 
situations can make it difficult for the driver to react correctly, and can cause the vehicle 
to become unstable. 

• 

The TCS helps to solve these problems by avoiding / reducing wheel spin. This is 
achieved either by reducing the engine torque by sending a corresponding signal to the 
PCM

 (Powertrain Control Module) and / or by applying brakeforce to the spinning 

wheel(s). 

• 

The TCS is incorporated to some ABS Hydraulic Unit/Control Module by minor changes 
to the basic system, but is also integrated to all DSC systems installed on Mazda 
vehicles. 

• 

Depending on the vehicle, different strategies may be used for the operation of the TCS. 
The most common is that, when the control module recognizes that the wheel speed of 
the driven wheels exceeds the wheel speed of the other wheels by a specified value, a 
signal is sent to the PCM to reduce the engine torque. The PCM accordingly reduces the 
engine torque output by closing the throttle valve (only on vehicles with electronic throttle 
valve), adjusting the ignition timing, and / or by cutting fuel off. If the wheel spin still 
exceeds the limit or if the speed of one wheel exceeds the wheel speed of the other 
driven wheel by a specified value, brake force is applied by the hydraulic unit to the 
corresponding wheel(s). 

 
NOTE:

  TCS does not completely avoid wheel spin, it operates only above a specified limit of 

wheel spin. 

 

Curriculum Training 

01-15 

Fundamentals 

Dynamic Driving Safety Systems 

 

 

L2003_01012 

 

1  RF wheel 

8  Powertrain control module 

2  RR wheel 

9  Signal for torque reduction 

3  LR wheel 

10  ABS/TCS HU/CM 

4  LF wheel 

11  Applied brake fluid pressure 

5  Transmitted torque 

12  Brake calliper 

6  Engine with transmission 

13  Differential 

7 Engine 

control 

  

 
 

01-16 Curriculum 

Training 

Dynamic Driving Safety Systems 

Fundamentals 

Dynamic Stability Control 

• 

Due to external circumstances, such as an obstacle on the road, wet or slippery roads, 
or driving at inappropriate vehicle speed, a vehicle can reach critical limits, where the 
driver cannot keep the vehicle under control anymore.  

• 

The DSC improves vehicle handling and stability in these critical situations. A vehicle’s 
driving direction can be controlled by either turning the steering wheel or by a yaw 
moment built up by applying brake force to one wheel. The driver uses the steering 
wheel, whereas the DSC uses the brake system to control the vehicles driving direction. 

• 

The DSC constantly monitors the vehicle’s movement, not only the speed, but also the 
yaw rate, the lateral acceleration, and the steering angle. The control module calculates 
the direction the driver wants to drive to by using the steering angle. This is compared to 
the actual vehicle speed, the vehicle’s yaw rate, and lateral acceleration. If a critical 
situation is detected, the DSC accordingly applies controlled brakeforce and reduces the 
engine torque output as required (in the same way as for TCS operation), to ensure that 
the vehicle follows the desired direction. 

• 

The DSC uses an advanced ABS HU/CM and additional sensors. 

 

Curriculum Training 

01-17 

Fundamentals 

Dynamic Driving Safety Systems 

• 

The illustration shows the vehicle handling with and without DSC intervention in a critical 
situation. 

 
 

 

L2003_01016 

Obstacle suddenly appearing, vehicle without DSC 

 
 

 

L2003_01013 

Obstacle suddenly appearing, vehicle with DSC 

 

01-18 Curriculum 

Training 

 

 

 

 

 

 

 

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