VW Latest ESP+

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http://www.germancarfans.com/news.cf...kswagen/1.html

Volkswagen Reveals ESP +
Text & photos courtesy VW AG
edited 07-26-2004


Content
ESP + Driving Recommendation
ESP + Trailer Stabilisation
ESP Functions
ESP Accident Research
Passive Safety with the Golf as an Example


ESP + Driving Recommendation
Revolutionary ESP with steering intervention as of 2005, first of all in the Golf
New generation of ESP helps the driver to countersteer specifically
From mid-2005 onwards, Volkswagen will be launching a new generation of ESP for the Golf and other models with targeted power-assisted steering. Depending on the situation, the electronic stabilisation program sends impulses to the steering that cause the driver to move intuitively to countersteer correctly. In this way, ESP + driving recommendation contributes to reducing the braking distance by up to 10%, in particular on roads with different coefficients of friction (for example dry on the left, wet or snow-covered on the right).
The new system configured in this way can be used exclusively in conjunction with vehicles which – like the new Golf – have electromechanical power steering or another active steering system. This is why Volkswagen decided at a very early stage to launch the Golf onto the market with an "active" steering system as standard.


New ESP provides impulses for thinking and steering:
the actual decisions remain fully within the authority of the driver
Important: the new ESP does not assume the job of really steering the car, the actual decisions are to remain fully within the authority of the driver. It is much more the case that it provides a steering recommendation – even though this is clearly noticeable (with a maximum torque of 3 Newton metres). The example of road surfaces with different coefficients of friction shows in detail how efficiently the system intervenes: it is winter; one half of the road is dry, the other half still has patches of snow.


ESP today:
everything happens at the wheel with the lowest grip
Until now, the ideal scenario on these road surfaces with different coefficients of friction (known as µ split in technical jargon) in the case of full braking with ESP has been: thanks to ESP, the car does not start skidding; the driver is able to keep the car on track and avoid the obstacle.

However, as the braking effect has to orient itself to the wheel with the poorer coefficient of friction (here: on snow) in order to prevent the vehicle from swerving, the car cannot be braked as strongly as would actually be possible if the wheels were on a dry surface. Without countersteering in the correct direction, the car would swerve due to the "overbraking" of one wheel, as the asymmetric braking forces support a rotational tendency of the car towards the side of the road with better grip.


ESP tomorrow:
the wheel with the higher adhesion can now really get to grips
It is precisely here that the new ESP with driving recommendation sets in: the system "recognises" the direction in which the driver must countersteer to be able to brake the car without swerving. This is why the unit sends the command to the electromechanical power steering to issue a steering impulse in the required direction. The driver senses this, intuitively complies with the signal, and countersteers in the classical manner. This stabilising intervention means that the brake pressure at the wheels with the greatest grip can be increased. The consequence: the braking distance is reduced by up to 10%.


ESP and EPS:
Electrical Power Steering in the new Golf
All of this only becomes possible by networking ESP with an electromechanical steering system (EPS, Electrical Power Steering), as in the Golf. This is a so-called dual-pinion steering system. The power-assisted steering is provided by a servo motor. The two pinions (steering and drive pinion) apply the required steering force onto both the steering column and servo side into the conventional rack. Here, the steering pinion transfers the steering torque applied directly by the driver; the drive pinion transfers the power-assistance torque from the servo motor via a worm gear. This configuration means that there is always a mechanical connection between the steering wheel and the steering gear; the vehicle even remains steerable after failure of the servo motor. For the driving recommendation via ESP, this servo motor performs the key function, as it triggers the impulse in the steering wheel for countersteering.

Alongside the numerous dynamic advantages, the Golf steering system provides yet another decisive advantage: as the electromechanical solution - in contrast to the conventional hydraulic solution - only "works" in the case of a steering manoeuvre, the average consumption during real vehicle operation falls by approximately 0.2 litres.

During development, particular attention was paid to the sense of centring when driving straight ahead. The steering torque that builds up even with the smallest steering angles underscores the exact sense of centring. A contributing factor here is the active return of the steering; after cornering, the steering wheel returns automatically towards driving straight ahead. In addition, the "self-learning" steering features straight-ahead driving correction. The background: the system itself recognises inclinations in the road and countersteers this accordingly. The straight-ahead driving correction thus offers a significant comfort enhancement, as the driver remains relaxed and keeps the Golf on track without steering effort.
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This for sure will make car owners explore the limits of the car (at track) while not worrying about spinning out. However, I hope that computer also send out a signal to the steering on telling the driver when the counter steer is not needed, in avoiding the swing back effect.