Please enlighten me with power steering tech details

[g-force_addict]

I've tried too Google it w/o much success
Can you guys provide me some in-depth tech info or links about F1 power steering?

Specially regarding

* Response time, How do they allow power steering to react quickly to quick driver reactions to prevent the car from drifting?
* Steering feel, Obviously
* Reliability, many WRC cars power steering systems fail, besides the bumps they have to withstand continuous driver adjustments to keep the car on the road. F1 isn't much different as you see drivers continuously wobbling the steering wheel.

[amouzouris]

I've tried too Google it w/o much success
Can you guys provide me some in-depth tech info or links about F1 power steering?

Specially regarding

* Response time, How do they allow power steering to react quickly to quick driver reactions to prevent the car from drifting?
* Steering feel, Obviously
* Reliability, many WRC cars power steering systems fail, besides the bumps they have to withstand continuous driver adjustments to keep the car on the road. F1 isn't much different as you see drivers continuously wobbling the steering wheel.

if im not mistaking steering feel is given by having more feedback through the wheel...and less power steering so that the driver can feel the steering....thats as far as i know...

[olefud]

I've tried too Google it w/o much success
Can you guys provide me some in-depth tech info or links about F1 power steering?

Specially regarding

* Response time, How do they allow power steering to react quickly to quick driver reactions to prevent the car from drifting?
* Steering feel, Obviously
* Reliability, many WRC cars power steering systems fail, besides the bumps they have to withstand continuous driver adjustments to keep the car on the road. F1 isn't much different as you see drivers continuously wobbling the steering wheel.

Steering is basically mechanical linkage, so response would not be a problem -just modulating the boost. Same for feel; how much isolation. Different game if they were drive-by-wire.

Perhaps the WRC cars have to deal with more aggressive curbs, in which case the failure would be mechanical.

[Tim.Wright]

Steering feel is a massively subjective thing which is not so easy to quantify. It will be difficult to find reliable information on this without talking to an expert on the matter. I'm far from an expert, but can throw my 2 cents in based on what i know of road car systems.

My understanding is that the feel and feedback is the reason teams run hydraulic assistance instead of electrical. This seems to be the reason in road cars too. Hydraulics are so preferred that McLaren for example run a hydraulic system in the MP4 12C but the use an electric pump for the hydraulics instead of running a fluid line from the engine in the rear to the front. It would be easier just to use the electric motor to give the servo assist, but they prefer to have the assist through a hydraulic means.

In terms of response time, if you make the torsion bar quite stiff and run very high pressures with a lot of fluid velocity, this will minimise the response time.

Tim

[g-force_addict]

Steering feel is a massively subjective thing which is not so easy to quantify. It will be difficult to find reliable information on this without talking to an expert on the matter. I'm far from an expert, but can throw my 2 cents in based on what i know of road car systems.

My understanding is that the feel and feedback is the reason teams run hydraulic assistance instead of electrical. This seems to be the reason in road cars too. Hydraulics are so preferred that McLaren for example run a hydraulic system in the MP4 12C but the use an electric pump for the hydraulics instead of running a fluid line from the engine in the rear to the front. It would be easier just to use the electric motor to give the servo assist, but they prefer to have the assist through a hydraulic means.

In terms of response time, if you make the torsion bar quite stiff and run very high pressures with a lot of fluid velocity, this will minimise the response time.

Tim

I'm confused.
In road cars when you turn off the power steering pump, for example when turning off the engine, steering becomes overly heavy much more than an identical car without power steering.
Thus how can reduced pump pressure provide feel without steering becoming unbearable heavy?

Do you guys have some tech info on the F1 power assisted rack and pinion?

[gixxer_drew]

I can't speak to F1 specifically but I think you are more interested in the power assist end which is simple on all the cars I ever worked on. Maybe you are trying to build your own system?

With electro hydraulic systems and a conventional style rack you dont see much load on the pump when the steering isnt in motion. So you dont build pressure without a load of some kind. There is no way around a basic response time as the pressure builds. Usually this is done with a simple restrictor to keep a certain base load. Smaller the restrictor, less response time to build pressure. I have done a similar system before. It was pretty straightforward, I just started with an adjustable restrictor measured sizes until it felt good to the driver and made a permanent one. Tried to use the biggest one I could get away with. It felt laggy around the paddock but driver said it felt great on track.

Make sure to have some kind of regulation so you dont over-pressure the rack and damage the seals. Formula cars have a really short lock to lock.

The electric saved a few horsepower on the straights over the mechanical and put weight lower with less MOI, less lines, in the end weight was still a little more, I used a fairly large pump.

When you play with your pump you can tell when its building pressure as the pump load goes up the whole sound of the pump changes. I started out with an expensive pressure sensor and when it broke I realized I didnt need it anyway and just went by feel and sound. Hope that helps.

[hardingfv32]

Maybe you are trying to build your own system?

I would say he is wondering why Lotus can not get their system right for Raikkonen. Why is it not just a matter of tuning/adjusting the pressure response or something? Any reason/advantage for their system to be different or more difficult to use?

Brian

[gixxer_drew]

My guess is: When the systems are running without much mechanical assist (very short lock to lock), heavy aero loads and going for the last bit of packaging, weight, power draw. A driver with faster inputs might want a lot less lag... especially oscillating direction of rotation at the wheel. That can be tough to reconcile when compromising with a strategy to keep from taking power off the engine... What works well for one driver might not for another and might not. The restrictor thing is a good example of one basic problem. If you put a small restrictor on you have great response but now you are pushing through a restrictor and pulling more power at all times. You also move less volume due to the tighter restrictor. As for control strategy, you can use pulse width modulation. I've never done this, but it might be hard to get right if you need a lot of response in all those conditions as well. If you needed hydraulics for other systems on the car as well and sharing a single pump could get crazy.

[marcush.]

I´d think you could start from here:


http://www.moog.com/literature/ICD/Form ... rticle.pdf
http://www.moog.com/markets/motorsport/ ... formula-1/