Dsc Control Outline; Vehicle Condition Determination; Oversteer Tendency Determination; Understeer Tendency Determination - Mazda 2006 MX-5 Service Highlights

DSC CONTROL OUTLINE

• While a vehicle normally turns safely in response to steering operation, there are instances when the limits of
tire lateral grip is surpassed due to road surface conditions or vehicle speed, and the influence of evasive
steering to avoid an accident or similar situations.
• Tires surpassing lateral grip exhibit one of the following conditions:
— Strong oversteer tendency: The rear wheels are relatively losing their grip as compared to the front wheels
— Strong understeer tendency: The front wheels are relatively losing their grip as compared to the rear
wheels
• DSC operates at vehicle speeds of 10 km/h {6.2 mph} or more in the conditions described above, controlling
engine output and wheel braking to suppress oversteer and understeer tendencies.

Vehicle Condition Determination

• The vehicle speed, steering angle, lateral-G and yaw rate are detected by the sensors and used in calculations
by the DSC HU/CM to determine the vehicle condition. Then, depending on the difference between the target
yaw rate, calculated with the values input from each sensor, and the value detected by the yaw rate sensor, an
oversteer or understeer tendency can be determined.
YAW MOMENTUM

Oversteer Tendency Determination

• When turning, if the actual vehicle yaw rate is larger than the target yaw rate (the yaw rate that should normally
be formed as determined by the steering angle and vehicle speed), it means that the vehicle is in or about to be
in a spin. Therefore the vehicle is determined to have an oversteer tendency.

Understeer Tendency Determination

• When turning, if the actual vehicle yaw rate is less than the target yaw rate (the yaw rate that should normally
be formed as determined by the steering angle and vehicle speed), it means that the vehicle is not properly
turning. Therefore the vehicle is determined to have an understeer tendency.
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DYNAMIC STABILITY CONTROL
UNDERSTEER CONDITION
LINE OF TRAVEL
TARGET YAW RATE
LINE OF TRAVEL
OVERSTEER CONDITION
LINE OF TRAVEL
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