Peugeot 207 RC Takes Control

2023 Author: Eric Donovan | [email protected]. Last modified: 2023-08-25 09:36

With the 207 RC, Peugeot is introducing a new safety system in the small car class. The SSP automatically counter-steers when braking on surfaces with different levels of grip.

By Sebastian Viehmann

ABS, ESP, ASR, EDS - the wealth of electronic systems in cars has become overwhelming. Now Peugeot is also coming and wants to make a new technical marvel palatable to us with the SSP (Steering Stability Program). The steering stability system is supposed to prove its ability on the so-called “Mü-Split” route. The unit Mü denotes the coefficient of friction of a surface. The higher the coefficient of friction, the more force you have to use to set a body in motion on this surface. A Mü-Split route consists of surfaces with different coefficients of friction, for example a road that is half icy. If the wheels brake on the two surfaces with different coefficients of friction, a yaw moment arises that can ultimately lead to the rear breaking away.

EPS reduces braking performance

A Mü-Split route is particularly dangerous for cars that do not have an anti-lock braking system (ABS). Because the brake pressure on the wheels is not regulated differently, cars without ABS on the Mü-Split route quickly become unstable. When the wheels lock, the car turns like a top. ABS regulates the brake pressure on the wheels and prevents them from locking. However, this can increase the braking distance, and corrections must be made to the steering wheel to keep the car on track. The electronic stability program ESP ensures even more safety. It recognizes the different levels of grip of the wheels on the road. To keep the car on track, ESP limits the use of the brakes where there is greater grip. However, this is at the expense of the maximum possible braking power,and the pressure build-up in the brake depends on the steering angle.

Counter-steering maneuver after 100 milliseconds

The SSP system, which is available for the first time in the Peugeot 207 RC, networks the ESP with the electric power steering. With SSP, the tires can be braked more strongly on the grippy part of the road. To prevent the car from becoming unstable, SSP automatically begins a counter-steering maneuver after less than 100 milliseconds. "The driver is supported by an additional steering torque to find the optimal steering angle," says Peugeot. The recommended steering angle can be up to 80 degrees. Sounds good - but how does it all work in practice? At the Peugeot test site in Belchamp, we compared a 207 RC with and without an SSP. Since the SSP is networked with the ESP, the first test car only had ABS on board. At a speed of 80 km / h, we got into the iron on the Mü-Split route. With constant slight corrective movements, however, it was possible to keep the car on track.

Slightly shorter braking distance

Braking with SSP is initially very unusual: after a short time, the steering wheel becomes independent and jerkily performs the corrective movements. If you let go of the valance slightly, the 207 RC automatically stays on track thanks to the precisely coordinated counter-steering movements. The stopping distance is shortened slightly - Peugeot states that, depending on the operating conditions, a four to ten percent shorter stopping distance is possible. Incidentally, if you mess with the SSP, it plays the insulted liver sausage and switches itself off. So you can interrupt the automatic steering movements at any time with a little effort and take over the helm yourself. That makes sense - otherwise you wouldn't be able to avoid a sudden obstacle.