Car cornering - Has anyone done this


#1

I was curious if a car manufacturer has ever produced a car that, for instance, lowered the right side of the car when taking a right turn to (a) better distribute the load on the tires on the left and (b) make it more comfortable thru turns? I know that I am probably missing some physics basics, but it would seem to make sense to me.


#2

Yes. A few years ago Mercedes produced a very high SL model with an active suspension system that did this. I’m not sure if it made it into mass production.


#3

Back in the '60s, a Dutch inventor modified a Chevy sedan so that it “leaned into” turns. This innovation was reported in Car & Driver magazine, and they conducted a test drive of the one car that had been modified. The system used mechanical links connected to the tie rods in order to lean the car in the appropriate direction.

C & D verified that the man’s innovation did indeed work, but since it necessitated removing the coil springs and substituting rubber blocks, the ride quality was extremely harsh. The overall verdict was something along the lines of…interesting and promising, but in need of a lot more development work.

As far as I know, this innovation did not go anywhere.


#4

Mercedes Benz does in fact offer ABC (active body control) on many of its current cars. Mercedes began offering air suspensions (without today’s computer control) with the 300 SEL in the late 1960’s. Citroen had a hydraulic system on the DS in the 1960’s that had a similar effect.

Jaguar’s current system is appropriately called CATS (don’t remember what it stands for). Yes, these systems do allow the car to corner flatter and handle better. They are, however, a very expensive and complex systems. They consist of air springs/shocks on all four corners with sensors and computer controls which monitor wheel position/angles, etc. many times per second. Each air shock runs about $1,000 to replace and the air pump is around $2,500.

Mercedes is working on a radar-based system which scans the road ahead of the car and adjusts the suspension for potholes and other road irregularities.

They are great systems when they work, and expensive systems when they do not.

Twotone


#5

These systems create fantasy driving situations then, if you have enough money, you can live out your driving fantasies…Magazine road test drivers feel that a skid-pad is the appropriate place to test a car and that the results of these “tests” are very important…But 99% of the drivers on the real road do not even understand the concept and if they did, they could not care less…If the 3/4 ton pick-up truck ahead of you made it through the turn okay, so will you…


#6

Thanks everyone - very interesting!


#8

Air shocks? Dinosaur technology. GMs implementation of the electromagnetic shock has been around for some time in the Corvette and is a superior component for active suspensions. No need to scan ahead either because they are so fast to react.


#9

Mike Mac: I was curious if a car manufacturer has ever produced a car that, for instance, lowered the right side of the car when taking a right turn to … I know that I am probably missing some physics basics.

The frame of a fine handling car has to stay level. Aerodynamics and suspension use the flat platform as a base. Corvettes only have 4 inches of travel because they stay flat just about all of the time. It might help if the wheels leaned like on a Bike, or if the radius of the front wheels adjusted to the actual turn instead of staying parallel. But a car that leaned into" turns is not going to break any lap records.


#10

Actually, the system I alluded to in my earlier post actively changed the camber angle of the front wheels when turning. It compensates for the tendency of the rubber to “roll”, and keeps the tread flat relative to the road surface.

Other high-end cars use additional technology such as hydraulic systems to keep the body level, systems that lightly apply the outer rear brake to compensate for oversteer, and other fancy stuff.


#11

Amar Bose (Dr. Bose as those who work at Bose refer to him), had a pet research project about 6 years ago. He developed a car suspension system that would drive over potholes and bumps without the car ever rising or dipping. He got two patents in the 90s on absorbing vibrations and dynamically controlling a car’s suspension system.

I didn’t hear anything about it since it hit the presses back in 2005.


#12

If you enjoy leaning into corners, there is no substitute for a motorcycle.


#13

It would be nice to enjoy that sensation without worrying about wet leaves and sand on the road. At my age, I’ll take a couple of extra tires. My healing time is too great a % of the time I have left to live.


#14

My ol’ bod wouldn’t even tolerate the compromises of a motorcycle on a NICE day. My spine has pretty much “had it”.


#15

I have the wife thinking about one of these:

http://www.besportier.com/archives/2008-brp-can-am-spyder-grand-sport-roadster.jpg


#16

I’ve seen swarms of those in Daytona during Bike Week. Even with three wheels, they lean from side to side.


#17

I hear that. I finally got myself a home traction unit for my DDD. Still, on the right motorcycle, like a Goldwing, it feels pretty much like I am sitting on a couch.


#18

They lean like a car, right, away from the turn? You can see a video of one doing that here:

The Piaggio 3 wheeler does lean into the turn:


#19

Mike, You Are Describing Body Roll. A Way To Stop This Would Be To Invent An Anti-Roll Device.
All My Cars Already Have This Invention, Factory Installed Anti-Roll Bars.

From The Suspension Bible (carbibles.com): "The anti-roll bar is usually connected to the front, lower edge of the bottom suspension joint. It passes through two pivot points under the chassis, usually on the subframe and is attached to the same point on the opposite suspension setup. Effectively, it joins the bottom of the suspension parts together. When you head into a corner, the car begins to roll out of the corner. For example, if you’re cornering to the left, the car body rolls to the right. In doing this, it’s compressing the suspension on the right hand side. With a good anti-roll bar, as the lower part of the suspension moves upward relative to the car chassis, it transfers some of that movement to the same component on the other side. In effect, it tries to lift the left suspension component by the same amount. Because this isn’t physically possible, the left suspension effectively becomes a fixed point and the anti-roll bar twists along its length because the other end is effectively anchored in place. It’s this twisting that provides the resistance to the suspension movement. "

It’s all in the Bible. Check it out.

Read more: http://www.carbibles.com/suspension_bible_pg4.html#ixzz1IIDpl4Gz

CSA


#20

I have thot for a long time that we should RAISE the car on the outside of the turn It could be done hydraulicly over springs.


#21

Raise The Car On The Outside Of The Turn ? Done That. It’s Called A Banked Turn.

CSA