Power steering in new cars

[SilverFusion2010]

Originally Posted By: OneEyeJack
Isn't there a direct connection to the wheels with EPS and if the electrics fail you just end up with the problem of more effort to turn the wheel?


Yes

 

[Tomioka]

Originally Posted By: CKN
"New Tech Phobia" is prevalent on BITOG. Even when that new system (electric power steering) is inherently better because there are less moving parts and less to maintain.


LOL people will lose their minds once steer by wire becomes mainstream. Maybe with the elimination of the steering shaft GM can finally solve their intermediate steering shaft clunking problem that's been plaguing their trucks.

Infiniti has a hybrid steer by wire system which you can get it as an very expensive option. There is still a steering shaft which decouples in normal operation and engages if there is system failure.

 

[MCompact]

One clarification- steering feel is not the same thing as steering effort- although a lot of people use those term interchangeably.

Steering effort refers to how much force is required to turn the steering wheel.

Steering feel refers to how the steering system relays what is actually going on at the front wheels. For example, as cornering forces build up the steering effort should increase. Likewise, as the front tires reach their limit of adhesion the steering effort should decrease. The steering rack in the Club Sport is just about perfect in that respect. The M235i has a bit of feel, but I'd like more. Unfortunately, the typical US vehicle operator("driver" is much to generous a term) prefers isolation over information.

 

[OVERKILL]

Originally Posted By: MCompact
One clarification- steering feel is not the same thing as steering effort- although a lot of people use those term interchangeably.

Steering effort refers to how much force is required to turn the steering wheel.

Steering feel refers to how the steering system relays what is actually going on at the front wheels. For example, as cornering forces build up the steering effort should increase. Likewise, as the front tires reach their limit of adhesion the steering effort should decrease. The steering rack in the Club Sport is just about perfect in that respect. The M235i has a bit of feel, but I'd like more. Unfortunately, the typical US vehicle operator("driver" is much to generous a term) prefers isolation over information.


That was one of the things I really noticed between the M5 and the SRT Charger. The M5 had incredible steering feedback, whilst the Charger felt a bit more vague. Not as vague as the Expedition, sweet Jesus, that's a whole other planet of vague, but Just not as "connected". Actually, I'd argue the Jeep feels less isolated than the Charger did, though still not approaching the level of feedback the M5 provided.

 

[nthach]

Originally Posted By: Kibitoshin


Infiniti has a hybrid steer by wire system which you can get it as an very expensive option. There is still a steering shaft which decouples in normal operation and engages if there is system failure.


I was about to say Infiniti - and initial reports weren't favorable. With the advent of demi-automation in new cars, keeping the mechanical linkage between steering wheel and gear while using a bolt-on EPS unit and offering lane keeping assist and self-parking is how it's done - and cheaper than getting rid of the mechanical linkage until the technology matures. If aviation is any example, Airbus killed the mechanical rudder/aileron linkages on the A320 and used fly-by-wire for those controls.

Having a fail-safe might still require the linkage. I wonder if Tesla got rid of the linkage between steering wheel and gear - they are the first self-driving car to market, well not all the way there but it's on the market.

 

[OVERKILL]

Wanted to mention that some vehicles also have modifiable Power Steering parameters. These are the ones from my Jeep for example:

 

[PeterPolyol]

Back in the day when I wanted to change the electronically-controlled hydraulic power steering assist in my '88 626, I had to move a switch on the control unit under the drivers seat.

Originally Posted By: Kuato
Give me a good 'ole hydraulic system any day.

GM felt this way after the column-mounted EPS on 04-05 Malibu/G6 began giving trouble. They went back to hydraulic on 2006 up for a few years until they sorted it out. Despite being a totally manual rack, EPS feedback is still 'meh'

 

[B320i]

Originally Posted By: SteveSRT8
Not sure what you are talking about. Every vehicle I have seen including our 14 RAM has a system that is always directly connected to the wheels. pretty high effort (I pulled the fuse once) but always there no matter what.

Absolutely the most direct and accurate steering I have ever driven...

Well, that proves me a nincompoop!

Had thought the mechanical linkage had been completely done away with given EPS. Guess not - at least not yet.

 

[SteveSRT8]

Originally Posted By: B320i
Originally Posted By: SteveSRT8
Not sure what you are talking about. Every vehicle I have seen including our 14 RAM has a system that is always directly connected to the wheels. pretty high effort (I pulled the fuse once) but always there no matter what.

Absolutely the most direct and accurate steering I have ever driven...

Well, that proves me a nincompoop!

Had thought the mechanical linkage had been completely done away with given EPS. Guess not - at least not yet.


Don't feel bad, I didn't even know it was standard on newer RAMs! tech moves fast these days...

 

[bunnspecial]

Originally Posted By: SilverFusion2010
My 2010 fusion has electric power steering. I think we are well past the gimmick stage


Interesting-my MKZ(Fusion based) of the same year has conventional hydraulic. My dad's 2015 MKS(Taurus) has electric. I wonder if the difference on the MKZ vs. the Fusion comes down to the Fusion being available as a hybrid while the MKZ was not.

BTW, who need power steering anyway?

One of the cars in my signature doesn't have P/S, or power anything for that matter. The steering rack stays bathed in EP-90 gear oil that's held in place with the help of the rack gaiter boots. Granted the car weighs a shade over a ton, has little bitty tires, and a 15" steering wheel(although I've driven them with 14" steering wheels and they're fine). The only time the lack of P/S is really noticeable is at slow speed-unfortunately when you're parking you miss it the most. It will QUICKLY break you of the habit of "dry steering"-i.e. turning the wheel without the car moving(a condition that's really hard on hydraulic P/S systems esp. at lock even though most folks aren't aware of it). Also, I think it's 2 1/2 turns lock-to-lock-all combined it's a system DESIGNED to not have P/S and it shows. As is fitting for a sports car, the steering feedback is phenomenal-you feel EVERYTHING through the wheel and once you recognize what something feels like(i.e. a wheel about to lose traction) you can react before it happens.

BTW, I have to admit that I'd be uncomfortable with the mechanical linkage going away. In a complete loss of power situation(which can happen on a car, albeit exceptionally rarely) I still want to be able to steer and brake. Heck, if the battery is dead, I want to be able to roll and steer the car if need be. That's not exactly easy on today's cars, but at least it can be done.

 

[4WD]

My Explorer (Taurus) and Fusion (Hybrid) have EPS ...
IIRC - our 2010 MKX was hydraulic ...

 

[meep]

Originally Posted By: SteveSRT8
Originally Posted By: B320i
Originally Posted By: SteveSRT8
Not sure what you are talking about. Every vehicle I have seen including our 14 RAM has a system that is always directly connected to the wheels. pretty high effort (I pulled the fuse once) but always there no matter what.

Absolutely the most direct and accurate steering I have ever driven...

Well, that proves me a nincompoop!

Had thought the mechanical linkage had been completely done away with given EPS. Guess not - at least not yet.


Don't feel bad, I didn't even know it was standard on newer RAMs! tech moves fast these days...


Agreed, and actually, referring to the original post, if I recall there's another EPS system that does use hydraulic pump, cylinder, and fluid, just electrically driven.... so there's a lot out there to track.

 

[nthach]

The first and second generation Mini Cooper S and the second generation Toyota MR2 uses hydroelectric power steering - the Mini pumps are fan cooled and do go out when the car gets older.

 

[CR94]

Originally Posted By: meep
... Agreed, and actually, referring to the original post, if I recall there's another EPS system that does use hydraulic pump, cylinder, and fluid, just electrically driven ...
Yes. Some Mazdas did that. Mine was non-power, fortunately.

 

[pezzy669]

Originally Posted By: CR94
Originally Posted By: meep
... Agreed, and actually, referring to the original post, if I recall there's another EPS system that does use hydraulic pump, cylinder, and fluid, just electrically driven ...
Yes. Some Mazdas did that. Mine was non-power, fortunately.


My '10 and '15 Mazda 3 were a type of hybrid system between a true EPS and hydraulic. It simply just removed the belt pulley and made the pump electrically driven. If I remember correctly Mazda did this so the steering would not feel artificial which was previously an issue for true EPS systems. You can hear the electric pump sing when you hear a late model Mazda doing parking maneuvers, not sure if they have moved to a true electric system since my '15.

My '06 Jetta had a true electric system where I believe a motor was on the shaft itself down by the rack, it was a pretty good system but there were times in busy traffic parallel parking maneuvers I could overwhelm the motor and it would hammer back at me in protest and I would have to slow down my whipping of the steering wheel.

 

[chrisri]

It has been for over 15 years now. My O6 Fiat Stilo has one and it was completely reliable. It even has CITY mode (super light steer that automatically disengage at 60 kmph). There are two types of EPS, column mounted and rack mounted. Later are known for better feel.