Load change reaction
A load change reaction is understood to be the change in the driving behavior of a vehicle that occurs due to a deceleration caused by releasing the gas while cornering. The engine torque changes from pulling to pushing operation .
The stronger the delay, the stronger the load change reaction. The load change reactions are influenced by the engine drag torque, the gear ratio, the wheelbase and the kinematic and elastokinematic toe angle changes during compression / rebound, as well as the tire properties. Other influences can be a high center of gravity of the vehicle and a soft suspension with poorly coordinated damping. The load change in a circle is one of the standard maneuvers of driving dynamics that are carried out in the "open control loop". The implementation and evaluation was specified in ISO 9816.
By increasing the wheel load on the front axle or reducing the rear axle, the lateral forces change accordingly. There is a turning yaw moment, which reduces the radius driven . When driving in the limit area , strong load change reactions can endanger the stability of the vehicle. Large sideslip angles can occur.
In modern automotive engineering, load change reactions are reduced in several ways:
- Driving comfort : When switching to overrun, the engine control does not suddenly switch to overrun cut-off ( switch off fuel supply) (as was previously the case ), but instead regulates the engine output with a delay. Vehicles with manual gearboxes also have a switch on the clutch pedal for this purpose.
- Safety: In critical situations, the electronic stability program (ESP) controls the engine drag torque or initiates an override.
See also
literature
- Hans-Hermann Braess, Ulrich Seiffert: Vieweg manual automotive technology. 2nd edition, Friedrich Vieweg & Sohn Verlagsgesellschaft mbH, Braunschweig / Wiesbaden, 2001, ISBN 3-528-13114-4