Mazda Training manual - part 99

 

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Mazda Training manual - part 99

 

 

Dynamic Driving Safety Systems 

DSC 

• 

The DSC counteracts this tendency by applying brake force to one or more wheels (in 
this case to the inside rear wheel). Thus a momentum is built up, overcoming the 
tendency of the vehicle to continue in a wider circle than intended, as shown in the 
illustration below. 

 

 

L2003_02033 

 

Direction of travel with DSC intervention 

Counteracting yaw moment 

Direction of travel without DSC 
intervention 

Brake force applied 

 

During DSC Control 

• 

The brake force is applied in three ways: 

– 

Pressure increase mode 

– 

Pressure hold mode 

– 

Pressure reduction mode 

• 

These modes will be explained on the following pages. The sample is for a vehicle that is 
oversteering during a left turn. 

 
 

Curriculum Training 

02-55 

DSC 

Dynamic Driving Safety Systems 

Pressure Increase Mode 

• 

Based on the input signals, the stored map values and internal calculations, the CM 
recognizes that the vehicle is about to oversteer during a left turn. The CM decides 
whether it is necessary to actuate the brake system and/or to reduce the engine torque. 
The following steps explain how the vehicle is kept on the track by activating the brake 
system. 

 
NOTE:  If the CM decides that the engine torque has to be reduced, it sends a corresponding 

signal to the PCM. The PCM then reduces the engine torque by cutting the fuel off, 
changing ignition timing and/or by closing the throttle valve (only on vehicles with 
electronic throttle valve). 

 
• 

When the CM decides that it is necessary to apply brake force to the outer front wheel to 
keep the vehicle under the driver’s control, it actuates the traction control solenoid valve 
in the brake circuit for the RF and LR wheel. This is done to separate the brake circuit 
from the brake master cylinder and to enable the pump to build up pressure in the 
corresponding brake circuit. 

• 

To make sure the DSC operation for the RF wheel does not affect the LR wheel, the CM 
activates the LR inlet solenoid valve. 

• 

The stability control solenoid valve for the RF and LR wheel is actuated and opens a 
channel to supply a sufficient amount of brake fluid to the high-pressure pump. 

• 

The pump motor is switched on, pressure in the RF brake circuit is built up, and brake 
force is applied to the wheel. This counteracts the undesired yaw force neutralising the 
oversteer tendency, allowing the driver to maintain control. 

 

LF-RR

OFF (open)

RF-LR

ON (closed)

LF-RR

OFF (closed)

RF-LR

ON (open)

LF
RF
LR

ON (closed)

RR

OFF (open)

LF
RF
LR
RR

Pump motor

ON (operating)

L2003_T02016

Traction control solenoid valve

Inlet solenoid valve

Outlet solenoid valve

OFF (closed)

Stability control solenoid valve

OFF (open)

 

 
 

02-56 Curriculum 

Training 

Dynamic Driving Safety Systems 

DSC 

 

 

L2003_02034 

 

Master cylinder 

Outlet solenoid valve 

DSC HU/CM 

Brake calliper LR 

Damper chamber 

10 

Brake calliper RF 

Pump motor 

11 

Flow control valve 

Pump 

12 

Stability control solenoid valve 

Reservoir 

13 

Traction control solenoid valve 

Inlet solenoid valve 

14 

Brake fluid pressure sensor 

 
 

Curriculum Training 

02-57 

DSC 

Dynamic Driving Safety Systems 

Pressure Hold Mode 

• 

After the appropriate pressure has been built up, the DSC switches to the pressure hold 
mode and deactivates the high-pressure pump. The RF-LR traction control solenoid 
valve remains actuated, while the RF-LR stability control solenoid valve closes, because 
it is deactivated by the CM. In addition, the RF inlet solenoid valve is activated. The LR 
inlet solenoid valve remains closed during the entire process. 

 

LF-RR

OFF (open)

RF-LR

ON (closed)

LF-RR

OFF (closed)

RF-LR

OFF (closed)

LF

OFF (open)

RF
LR
RR

OFF (open)

LF
RF
LR
RR

Pump motor

OFF (stopped)

L2003_T02017

Traction control solenoid valve

Inlet solenoid valve

Outlet solenoid valve

OFF (closed)

Stability control solenoid valve

ON (closed)

 

 
 

02-58 Curriculum 

Training 

 

 

 

 

 

 

 

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