Big announcement here guys: My racecar aero course is all edited and finished! It will be launching at the start of next month, don't forget to register your email here for updates: jkfaero.thinkific.com/ There will a video coming out soon-ish explaining the launch, pricing etc. Thanks for your patience!
how do dampers switch the damping intensity/viscosity of fluid medium for fast vs slow bump, rebound. Is it possible to have a suspension that will be gentle on the drivers' bottoms (and allow for easier vision without porpoising shakiness) and still maintain stable aero platform (kinda like how f1 drivers would like the 2022 cars to be)?
Is it possible to run a high aero car very high off the ground and (highly) effectively use vortex generators to seal the underbody/tunnels/floor and also prevent rear tire squirt with the same vortex?
I wonder why they dont follow the same hydrolic system in motorcycles its just front vs back to control wheelies and endos It will be extremely simple for a motorcycle
@@FirstLast-tx3yj I strongly suspect that there are minimal gains on offer. By which I'm suggesting you couldn't increase the leverage required sufficiently enough to overcome the torque produced by a modern race bike anyway.
This is a masterpiece! Thanks for the explanation! During college, I've tried to come up with an architecture that would allow mode decoupling mechanically, but it was so cumbersome that I gave up. Then AMZ showed us how to do it properly with hydraulics. This system is pretty neat! Of course, it has its pros and also cons, but according to them, it was even possible to make the suspension system lighter. Also, it is interesting that due to tires compliance, it is not possible to fully decouple the warp mode! But of course, this system allows for a much more precise setup!
@@rizkiyoist AMZ is the Formula Student Team from ETH Zürich. They build prototype single seaters for the series. The team consists of students from different field and they have probably come up with it on their own (not sure)
I didn't understand any of that, but that probably means you have an advanced understanding of your subject material, and I can be glad there's another smart person somewhere in the world lol
@@rizkiyoist mechanical engineering will teach you how to create these systems but it just takes some clever person to think of such a incredible suspension idea
Thank you so much for this video! I’m building an active suspension for an RC car right now and your line stating that performance is related keeping the normal force on the tires constant made everything much more clear about the underlying goals of these active suspension control schemes.
I see many videos talking about the benefits of such control over the suspension, but never data Would be nice to put out a Vehicle Dynamics simulation video, showing the benefits on a simulated lap I'm sure there are benefits, but would be nice to quantify it - if spending millions on making such an hydraulic design only makes you car goes 0.1% faster over an ordinary track, then one must wonder if it is really worth it . A lot of the benefits comes down to the feedback to the driver, and how the car would be more predicable with such suspension, and this can be shown by sampling the car behavior on transients on a simulation
@@EmyrDerfel yeah, but not everything is formula 1 If I am building my own car, to race at a time attack, should I invest money in such a complicated design? Or should I spend the money on better aero? this is the kind of question would be nice to be answered. Not everyone has unlimited budget such as F1
www.researchgate.net/publication/242269184_MODE_DECOUPLING_IN_VEHICLE_SUSPENSIONS_APPLIED_TO_RACE_CARS The authors of this paper simulated a ~2006 F1 car with both traditional and mode decoupled suspension and found that over a 750 m sequence of short straights and 25m corners, the mode decoupled car was ~1 second faster, which amounts to about a 5% improvement. There were also clear benefits to platform stability.
@@satanaz I think the decoupling would have even greater benefits in a road car. F1 drives on extremely smooth surfaces (any motorsport that takes place on a track for that matter), and sure you get some mechanical grip benefits, but as another poster pointed out this is not hugely far from what Citroen introduced with the DS. it's all about controlling how the body mass behaves relative to the road, and today's roads in many places are extremely shit. The comfort benefit is hard to overstate.
@@satanaz Find a street legal and manual Cobra with the Pinto frontend and the Ford 9 rear axle. Overhaul suspension,add fox shocks with external reservoir, add stiffer swaybars and relocate Dedion downwards. Dry sump the SBC lower and move engine rearward by 5 inches and 3 inches down. Move tank forward and lower tank. 335/15 MT and 215/14 MT on Bassets. This gets you a though and durable chassis capable of hill climbs, slalom, drift, circletrack and, depending on gearing and engine HP, ...360kph or more topspeed, 2 secs 0-60 and 60000 miles between engine overhauls.
You forgot to put in the suspension for the driver's seat. All jokes aside, since you're connecting the front and rear, you've just made somebody at the FIA unhappy, and also made me _very_ happy~ EDIT: Electro-hydraulic suspension (hydraulic using an electric pump!, with harmonic dampers (aka Inerters / J-Dampers) and linear alternators. That would be the _real_ ultimate, in my honest opinion, because the linear alternators would also serve as energy recovery to recharge the hybrid systems through the suspension movement.
While it is most likely superior how reliable would this suspension be? If X suspension lasts Y laps then failure and potential wreck granting DNF for race results. I bring this up as I admired the Citroen hydro-pneumatic suspension which you could remove a rim from the vehicle and it would sustain being level with wheel hub floating capable of being driven as is being freaky as hell. Yet, it was far from reliable and discontinued. The entire design Kyle detailed reminds me of the Citroen system.
@@Cerberus984 I guess it just depends on how robust you build it. The Electro-Hydraulic thing is just normal hydraulics, but using a more efficient electric pump instead of a purely mechanical one. Meanwhile, the harmonic dampers and linear dynamos are more of just useful add-ons than anything else.
@@KYLEENGINEERS Righto, explains it. Speaking of that, considering how different ends of most racing cars are used for different things (front does most of the steering and braking, rear does the accelerating), and how you usually end up with a stiffer front than rear (again, in racing cars, stiffer rear for "flat ride" in road cars being another subject entirely), would you say that splitting the pitch mode into specifically dive and squat would also be important? We'll leave lateral asymmetry out of this, since it usually isn't desirable in road racing, but is of course a big thing in oval stuff.
@@jubuttib To some extent you can control the squat/dive split in terms of damping, as it is effectively the bump and rebound of the pitch damper. You can also make the springing change through a dual rate/position sensitive springing system, so that all can be covered off in terms of mode there. Now aero requirements front/rear is a different kettle of fish, particularly if you're trying to maintain a low front ride but don't care so much for rear, and this would definitely be a struggle to tune with this specific system. But that's a full extra video worth of content!
@@KYLEENGINEERS Right. I was thinking more in terms of lower (or even no) aero cars, how for example the McLaren MP4-12C GT3 car on its main spring set (softest FIA homologated for the 2013 season, nominally 1000 lbf/in front and 1200 lbf/in rear) ends up with about 125 N/mm front springs and 90 N/mm rear springs when measured at the wheel, which translates to roughly 3.5 Hz at the front and 2.7 Hz at the rear (not taking into account the sway bars). The different requirements between wanting a responsive and sharp feeling front end with enough pliability in the rear to allow you to put the power down. Looking at a lot of GT3 and GT4 car setup sheets I tend to see them set up with something like 20-35% higher front frequencies than rear (before sway bars). Was thinking if this would be something to take into account when designing a fully decoupled suspension. FWIW I work with racing simulators. =)
@@jubuttib I'm not a suspension expert, so can't be 100% sure, but I would've thought those handling characteristics can largely be achieved using forwards pitch/rearwards pitch control and a bit of roll stiffness biasing to cover off the rest of the wheel rate difference. Beyond that I know that typically in most cars I've worked on that we've ended up with stiffer corner springs on the front that the rear to get the aero platform control right (essentially a per axle heave stiffness approach), as the front ride height is significantly more sensitive than the rear (and we want the rear to drop under higher aero load), but not sure how much that would play a factor in your simulation (hopefully plays some role!). Perhaps some more of my viewers who are more knowledgeable in suspension tuning than myself would like to chime in at this point?
A while ago I had come up with an idea for hydraulic suspension but the version you drew was WAY more simple; mine was more automatic transmission inspired. I like your design more. Great video!
Fantastic, This is exactly what I was hoping for after the last one. The idea of making a mechanical system like that in my shed is interesting. The hardest part would be getting the dampers tuned for such an odd project.
I've always been curious as to what aero modifications you would do to a regular street car, such as a 350z or BMW 3 series, for making a fast track car with no restrictions. So doesn't have to meet any regulations. Can we get a video on that and the restrictions you'd have to overcome?
Love the vid but one thing on the video production. You have a very low frequency hum you might want to look at. Its very noticeable with headphones and a little distracting at times
It's the ultimate in mechanical grip as far as keeping the tires on the ground, but this video says nothing about the geometries of the suspension arms and steering which maximize the contact patch for the various loads and conditions they'll be facing. To that effect, I'd like you to do a video on slip angle and camber vs contact patch and load. Particularly for the rear suspension as I believe that a specific forgotten technology (the de-dion axle) can provide a massive benefit at the rear of a car for a driven axle. However, I also believe beam axles in general have the potential to provide benefit regardless of what end of the car they're on or whether or not they're driven. It's just that on the steering axle, you have to worry about packaging and the steering mechanism itself, more. In a short-travel suspension you could just put the steering rack ON the axle itself, but on a mid and especially long-travel suspension (and/or if the driver/steering shaft line is massively off-axis of the steering rack) it becomes a much more difficult question.
Warp effects can be largely negated by having the roll axis inclination and the mass centroid axis, broadly speaking, parallel. This results in the roll couple being equal from front to real. From a driver stand point, this generally makes for a car with a sound base of balance (and very responsive to balance changes). This may not be the path to ultimate grip, but if the car lacks balance then the driver cannot access the extra grip and it is all for naught.
I'm not understanding your hydraulic drawing. Doesn't the heave circuit equalize pressure between all four wheels, and therefore you don't have any roll or pitch stiffness?
Excellent explanation. I'd love to try building something like this when I'm designing in fsae. Looks hard to package though. With the electric motors I think a direct acting system would be easier to package than a bellcrank system. Still have no idea where most of it would go though.
I watched this video with the application on a formula student car in mind but thought it’s overengineered or to expensive but mentioning the amz have me hope to maybe building this into a formula student car
At 1:28 you say we can’t do anything to tune pitch and heave except by changing stiffness. What is the impact of anti dive and anti squat geometry then?
Hello KYLE! I think it would be cool if you made "the ultimate in aerodinamics" , pointing what would be a picture perfect setup. Covering body sape of the car and accessories. Thank you!
There's a concept I've always been curious about, but I've never seen anyone really cover the suspension, geometry, and tire dynamics of it, a leaning quad with a low cg cockpit; essentially combining the leaning characteristics of a motorbike with the steering characteristics of a four wheeled vehicle. One specific question I've always had is about the leaning of the various components, say if the body of the vehicle leans to a specific degree, do the inner and outer wheels lean to the same degree, or should there be some kind of differential between the components where it's inner wheel has a greater angle of lean than the body and the body also has a greater angle of lean than the outer wheel, x>y>z, all from a reference of a straight up and down 90°; a leaning variant of ackermann geometry, essentially. Another specific question I have pertaining to this is how this leaning would interact with steering, such as if ackermann geometry is still relevant, which of lean and steering is more important, etc. Then after those two, assuming both are equally important, and if leaning does have it's own analog of ackermann geometry, how this would incorporate into a suspension system, specifically an independent leaning suspension. I have yet to find anyone actually research this kind of concept. The most I've found are leaning trikes where performance is an afterthought. But my curiosity is if this kind of concept were thrown into a motorsports category where everything is fine tuned for performance.
I'd love to see a really cool design build in bricks :D Maybe part by part just the suspension. Another part could be the steering, maybe with DAS. Another would be engine and radiators. And the last one just some nice cosmetics. To finally have a reall nice brick car that has all the important features. Maybe even gears and shift :D
Jesus Christ a computer controlled active suspension would be not only MUCH effing easier but way less complex and cheaper. Thanks Bernie and the boys from 1993…
That´s crazy. I think that the hidraulic flows slowly, (you can use other liquids that flows better) i think that a pneumatic suspension with some electrovalves and a shock asorber can do that. An individual suspension without roll, pich, but never forget the most important part. The suspension desing, you can use a good suspension elements but if you use a torsion bar instead of doble whishbone or multi link the resuslt won´t be the best. I am intrigued how williams did in f1 in 1991 to control the suspension, there ins´t any information. PD: I have a citroen bx that was from my uncle, and most people thinks that is awesome, but in my opinion the suspension is bad, dont get me wrong. when i fist drive the car, i was in a small city and i thougth, oh the road is very nice and flat, but in reality, there arent. The suspesion is the soft suspension that i drove, but it feels very, very stiff because you goes every time really FLAT, is realy independent and self-leveling (the leveling is slow, like 0-5/1second) The shock absober(spheres) and hidraulics are the best. But the problem is that in the rear the car uses torsion bar and this ruins the setup, some roll and pich... For example bmw. are cars with a setup with little dive and squat, and roll. The most important is the GEOMETRICS
The hydraulic fluid won't have to flow very far and you want hydraulic fluid as you want to keep the expansion of the hydraulic lines down as the system would be harder to predict the needed spring rates. And possibly by the time the air starts to create enough pressure to move the piston it's too late. In sense the air is a spring and you don't want that, same as expansion of the hydraulic lines. You could possibly use valves to control the hydraulic fluid flow but it would lead to minimal gains if any. Active shock absorbers on each individual piston setup would be best but it's unclear how much of a gain it would give. Your are correct that suspension design is the most important thing but a torsion bar is just another spring and they use them in F1. You should have said torsion beam suspension which in that case you would be correct that it is not ideal. Williams has kept their suspension a secret in case active suspension resturns in case you didn't know and that's why there is no info on it. Some people believe it's close to what is called the FRIC suspension which was used until 2014.
yes and no as its not near as complex, if im correct they only connect the front and rear for pitch control. they also use valves at the top and bottom of the wheels dampener. the mclaren setup still doesnt control heave or really anything independently. he has a vid on his channel about the 720s suspension
instead of messy hydraulic.. how about electromagnetic suspension? basically something like this but replace the pistons with electromagnets, then send the data to the CPU, process the modes individually, actively manages the displacement data, then send feedback to each suspensions. ultimately creating an active suspension.
Bose has done this before. They found that, while the ride quality of the car was amazing, it would be too heavy, too inefficient, and too costly/complicated to realistically implement in a car. The electromagnets would have to be quite powerful, meaning that they'd draw a lot of current. Maybe it could work better with assistance from some other device.
Maybe I'm just being stupid but if hydraulic fluid is incompressible, wouldn't this system not just immediately seize ? Under heave the pitch &roll circuits would seize, under roll the heave and pitch circuits would seize and etc.
You get your "head space" in the heave piston, which can always move up and down. All the other pistons lock up by design when they are pressurized on both sides, that's what allows each one to control only one mode: they will only move for the mode that creates unequal pressure in that piston. You don't want, e.g., the pitch piston to move under heave, you want 100% of that motion controlled by the heave piston alone. Under pure heave every other piston will remain stationary.
What would happen if going through a hard right turn you ran over a curve with that right tire? The right front tire will compress and the left rear will lift? This would cause the rear right to drop and the left front to raise. Now if this was instantaneous it seems like it would work. But real world the potential delay between front and rear would seem that would raise concerns. That is of course with no failures in any point of within the system due to uneven seal wear or fluid viscosity changes at different temperatures as one corner is worked harder then the others.
It would be tuned accordingly. So the damping and spring affect between the corners could be relatively light. It all depends on the type of car and conditions. I very high cog vehicle on rough terrain would benefit the most. I’d like to see a baja race car with and without it compared.
Is it possible to do it now all electronically. i mean using sensors and actuators. this saves on oil spillage and one can competely configure the system by means of SW and adapt it dynamically and based on the terrain conditions and needs.
yes, the Williams f1 car from the 90s is a good example of this but be aware pretty much every other team who try doing this cost the driver their lives.
Can you do an aero or also suspension analysis on the GTWC cars? So like 488 gt3... and other GT3... Maybe with a comparison of each one... Thanks... and sorry for the bad english:):)
would it make sense to have a dumper in the mid instead of just a rod? For example, a car goes through a hill climb? Is it a dumb question? It's soo custom.
Now, if only some could put a pump and some valves in the system you could control the suspension for every bend ;) on a serious note, I thought that connecting the front and rear suspension was illegal in F1. I also thought that using hydraulics to connect the wheels was also band?
No, its totally passive. Active suspension had a pump that added energy to the system/fluid to control the attitude of the car. This is a passive system, the car still rolls and pitches as if it had springs, we are just using the hydraulic fluid to carry and/or redirect the loads going through the suspension.
Now I feel bad for my design for a suspension of a solar car hahaha,as I only have time to design the front I cant control the roll nor pitch of the entire car.
Could you explain how the suspension is attached to the chassis? I know flexure joints are being used instead of ball joints. But I wonder how they are mounted an stuff
1) on a non aero car, would there be no need for heave control? so if you ran a T-bar setup you could tune your pitch characteristics freely using the "heave"/pitch spring and damper? 2) for a road car do you think a hydraulic piston actuator for the decoupled mode suspension would be easier to package than a cantilever and T-bar setup? the reason I'm asking is because it seems like you can move the springs and dampers to anywhere in the car instead of having components that require a fixed position and geometry near the wheels. 3) would a single piston with a single hydraulic line be sufficient to control each wheel? does anyone actually do this on a 1000kg+ car? 4) implementing this system with air springs and adjustable MRF dampers would be super cool. would there be an disadvantages to this other than complexity?
1)the heave would still be ideal to in essence carry the cars weight. 2) it would be the same size to package as a conventional setup around the wheels but you are correct everything else can be moved around where there is space but it is best to minimize the length of lines as you would have less control from the expansion of lines.3) yes a single hydraulic piston of sufficient size and rated for the forces is all you need along with one line that would go to a distribution module where the other lines would be connected. so you would only have a single line from each wheel and then close to the pistons you have the distribution blocks where you would have mess of hydraulic lines to the proper pistons. currently only prototype vehicles use this as no professional series allows it and it is just too untested and costly for a road car as of right now.4) assuming you are using air springs and dampeners on the pistons it would just give you a different characteristic but i would be cautious of excess heat messing with your spring pressures. in sense regular springs are linear and follow F=K(x) where f is the force needed to compress X distance and K is the spring coefficient. Air follows a different trend where is easier to compress at first but as the pressure increases its spring coefficient dramatically stiffens. on a road car its better to stay with normal springs as they are easier to predict, but air suspension is big in off road where you want the wheels to articulate easily at first and to get much harder as they come to the end of travel so you don't bottom out. suspension geometry also does this especially using a cantilever suspension as the angles of the pushrod and the dampener can change the forces acting and being acted by the wheel. This is where you spend millions in engineering.
hard to change up suspension mounting points mid race plus it puts more force on the suspension pickup points. best to us spring systems but if you cant then use geometry
@kyleengineers would it be possible to flip this design and run the push rods under the seat of a center seated car? It imagine it would require flipping the suspension pushrod as well, attaching it to the top control arm and the rocker, shocks and springs attaching to the bottom frame.
...I quietly wonder if there'd be any point to running a hydraulic system like this in something with a lot of travel. like...30" of travel or more, attached to 66" tires. The "hydraulic pistons" are already there in the form of the nitrogen gas shocks the big trucks run. Main thing would be keeping all that oil cool (and in the lines) through the 2 or 3 minutes of a freestyle... ...thinking about it, fully decoupled suspension is probably way too sophisticated and expensive for Monster Trucks. But it's interesting to think on nonetheless.
If I had a whole lot of money I would love to try a system like this on my race buggy, have it all coming back to a central unit that could then have a full on cooling circuit with a radiator to keep the whole thing cold! One day someone will develop it...
@@KYLEENGINEERS At least aspects of it, sure. Tying the front and rear shocks together for pitch control would definitely help a lot of the off-road racers, since with the soft springs they really squat and dive. Warp maybe not so much, guys like the articulation for the uneven surface, though separating that from roll control would probably be a good thing. Who knows?
The super high CG of monster trucks makes it kind of an ideal application for some sort of front/rear interconnect. I don't think it would worth going full decoupled but there's plenty of space for a bar running front to back that could give some real benefits in squat and dive.
the fluid doesn't actually flow into the same reservoir in each cylinder, they are separated, i.e. you might have a cylinder with 4 chambers, pairs of 2 chambers are connected and each pair works against the other
Hi Kyle. I was wondering where the forces from those four decoupled mode dampers go? They would be mounted directionally in the chassis somewhere to use that force to help the car? Can you illustrate that please you make me want to design a car!
They would be mounted to the chassis. I'm surprised I haven't seen anyone mention this, but Mclaren uses a VERY similar setup on their cars that are above the sports series (like the 720s). Many people say in comfort mode that it rides almost as smooth as a Rolls Royce, and stiffens right up whenever it's in track it sport mode. You can check out a video made by engineering explained where he explains it in detail.
Probably warp is beneficial for off road axle twist, and the pitch control and roll control would greatly benefit such vehicle on road driving dynamics to improve braking and cornering.
Big announcement here guys: My racecar aero course is all edited and finished! It will be launching at the start of next month, don't forget to register your email here for updates: jkfaero.thinkific.com/
There will a video coming out soon-ish explaining the launch, pricing etc. Thanks for your patience!
Awesome!
how do dampers switch the damping intensity/viscosity of fluid medium for fast vs slow bump, rebound. Is it possible to have a suspension that will be gentle on the drivers' bottoms (and allow for easier vision without porpoising shakiness) and still maintain stable aero platform (kinda like how f1 drivers would like the 2022 cars to be)?
Is it possible to run a high aero car very high off the ground and (highly) effectively use vortex generators to seal the underbody/tunnels/floor and also prevent rear tire squirt with the same vortex?
Formula Students: Write that down, Write that down.
Meanwhile bell cranks be like: Please take me out of single shear.
I should have put in some rod ends in bending for good measure
I wonder why they dont follow the same hydrolic system in motorcycles its just front vs back to control wheelies and endos
It will be extremely simple for a motorcycle
Killed me 😂👌🏼 and never forget to put the pushrod to damper ratio to 1:10 or sth and have fun with loads and rideheight setup
@@FirstLast-tx3yj I strongly suspect that there are minimal gains on offer. By which I'm suggesting you couldn't increase the leverage required sufficiently enough to overcome the torque produced by a modern race bike anyway.
This is a masterpiece! Thanks for the explanation! During college, I've tried to come up with an architecture that would allow mode decoupling mechanically, but it was so cumbersome that I gave up. Then AMZ showed us how to do it properly with hydraulics. This system is pretty neat! Of course, it has its pros and also cons, but according to them, it was even possible to make the suspension system lighter. Also, it is interesting that due to tires compliance, it is not possible to fully decouple the warp mode! But of course, this system allows for a much more precise setup!
I'm curious which degree do they learn about something this? Mechanical engineering? (I have no idea)
@@rizkiyoist AMZ is the Formula Student Team from ETH Zürich. They build prototype single seaters for the series. The team consists of students from different field and they have probably come up with it on their own (not sure)
I didn't understand any of that, but that probably means you have an advanced understanding of your subject material, and I can be glad there's another smart person somewhere in the world lol
@@rizkiyoist mechanical engineering will teach you how to create these systems but it just takes some clever person to think of such a incredible suspension idea
All the plumbing immediately reminded me about Citroen Xantia Activa and the Moose Test.
mclaren use it on his cars too. the supplier company is the american tenneco
@@AaaBbb-ff1pn
I thought that McL makes everything in-house.
@@jareknowak8712maybe they have a holiday home over there? Idk
Thank you so much for this video! I’m building an active suspension for an RC car right now and your line stating that performance is related keeping the normal force on the tires constant made everything much more clear about the underlying goals of these active suspension control schemes.
This is really interesting, and the ETH Zurich presentation is definitely worth a watch as well. Thanks Kyle!
Got a link to that?
@@mixalisstathis274 it's the second video Kyle linked in the description.
Maybe do a Valkyrie followup, since you covered it back in the day and they just ran the production spec at Goodwood?
I see many videos talking about the benefits of such control over the suspension, but never data
Would be nice to put out a Vehicle Dynamics simulation video, showing the benefits on a simulated lap
I'm sure there are benefits, but would be nice to quantify it - if spending millions on making such an hydraulic design only makes you car goes 0.1% faster over an ordinary track, then one must wonder if it is really worth it
.
A lot of the benefits comes down to the feedback to the driver, and how the car would be more predicable with such suspension, and this can be shown by sampling the car behavior on transients on a simulation
On a 1 min 40 sec lap, 0.1% is one tenth. That's a pretty big chunk in F1.
@@EmyrDerfel yeah, but not everything is formula 1
If I am building my own car, to race at a time attack, should I invest money in such a complicated design? Or should I spend the money on better aero?
this is the kind of question would be nice to be answered. Not everyone has unlimited budget such as F1
www.researchgate.net/publication/242269184_MODE_DECOUPLING_IN_VEHICLE_SUSPENSIONS_APPLIED_TO_RACE_CARS The authors of this paper simulated a ~2006 F1 car with both traditional and mode decoupled suspension and found that over a 750 m sequence of short straights and 25m corners, the mode decoupled car was ~1 second faster, which amounts to about a 5% improvement. There were also clear benefits to platform stability.
@@satanaz I think the decoupling would have even greater benefits in a road car. F1 drives on extremely smooth surfaces (any motorsport that takes place on a track for that matter), and sure you get some mechanical grip benefits, but as another poster pointed out this is not hugely far from what Citroen introduced with the DS. it's all about controlling how the body mass behaves relative to the road, and today's roads in many places are extremely shit. The comfort benefit is hard to overstate.
@@satanaz Find a street legal and manual Cobra with the Pinto frontend and the Ford 9 rear axle. Overhaul suspension,add fox shocks with external reservoir, add stiffer swaybars and relocate Dedion downwards. Dry sump the SBC lower and move engine rearward by 5 inches and 3 inches down. Move tank forward and lower tank. 335/15 MT and 215/14 MT on Bassets. This gets you a though and durable chassis capable of hill climbs, slalom, drift, circletrack and, depending on gearing and engine HP, ...360kph or more topspeed, 2 secs 0-60 and 60000 miles between engine overhauls.
curious how mclaren is using the citroen hydro-pneumatic spheres in their fric exactly...
You forgot to put in the suspension for the driver's seat.
All jokes aside, since you're connecting the front and rear, you've just made somebody at the FIA unhappy, and also made me _very_ happy~
EDIT: Electro-hydraulic suspension (hydraulic using an electric pump!, with harmonic dampers (aka Inerters / J-Dampers) and linear alternators.
That would be the _real_ ultimate, in my honest opinion, because the linear alternators would also serve as energy recovery to recharge the hybrid systems through the suspension movement.
While it is most likely superior how reliable would this suspension be? If X suspension lasts Y laps then failure and potential wreck granting DNF for race results. I bring this up as I admired the Citroen hydro-pneumatic suspension which you could remove a rim from the vehicle and it would sustain being level with wheel hub floating capable of being driven as is being freaky as hell. Yet, it was far from reliable and discontinued.
The entire design Kyle detailed reminds me of the Citroen system.
@@Cerberus984 I guess it just depends on how robust you build it.
The Electro-Hydraulic thing is just normal hydraulics, but using a more efficient electric pump instead of a purely mechanical one.
Meanwhile, the harmonic dampers and linear dynamos are more of just useful add-ons than anything else.
0:24 I thought I saw more people asking about heave, dive and squat not being decoupled? Fantastic video regardless, as always.
Yeah, I misspoke a little sorry, pitch and heave coupling was definitely the bigger question! All good, I cover it anyway :)
@@KYLEENGINEERS Righto, explains it. Speaking of that, considering how different ends of most racing cars are used for different things (front does most of the steering and braking, rear does the accelerating), and how you usually end up with a stiffer front than rear (again, in racing cars, stiffer rear for "flat ride" in road cars being another subject entirely), would you say that splitting the pitch mode into specifically dive and squat would also be important? We'll leave lateral asymmetry out of this, since it usually isn't desirable in road racing, but is of course a big thing in oval stuff.
@@jubuttib To some extent you can control the squat/dive split in terms of damping, as it is effectively the bump and rebound of the pitch damper. You can also make the springing change through a dual rate/position sensitive springing system, so that all can be covered off in terms of mode there. Now aero requirements front/rear is a different kettle of fish, particularly if you're trying to maintain a low front ride but don't care so much for rear, and this would definitely be a struggle to tune with this specific system. But that's a full extra video worth of content!
@@KYLEENGINEERS Right. I was thinking more in terms of lower (or even no) aero cars, how for example the McLaren MP4-12C GT3 car on its main spring set (softest FIA homologated for the 2013 season, nominally 1000 lbf/in front and 1200 lbf/in rear) ends up with about 125 N/mm front springs and 90 N/mm rear springs when measured at the wheel, which translates to roughly 3.5 Hz at the front and 2.7 Hz at the rear (not taking into account the sway bars). The different requirements between wanting a responsive and sharp feeling front end with enough pliability in the rear to allow you to put the power down.
Looking at a lot of GT3 and GT4 car setup sheets I tend to see them set up with something like 20-35% higher front frequencies than rear (before sway bars). Was thinking if this would be something to take into account when designing a fully decoupled suspension.
FWIW I work with racing simulators. =)
@@jubuttib I'm not a suspension expert, so can't be 100% sure, but I would've thought those handling characteristics can largely be achieved using forwards pitch/rearwards pitch control and a bit of roll stiffness biasing to cover off the rest of the wheel rate difference. Beyond that I know that typically in most cars I've worked on that we've ended up with stiffer corner springs on the front that the rear to get the aero platform control right (essentially a per axle heave stiffness approach), as the front ride height is significantly more sensitive than the rear (and we want the rear to drop under higher aero load), but not sure how much that would play a factor in your simulation (hopefully plays some role!). Perhaps some more of my viewers who are more knowledgeable in suspension tuning than myself would like to chime in at this point?
A while ago I had come up with an idea for hydraulic suspension but the version you drew was WAY more simple; mine was more automatic transmission inspired. I like your design more. Great video!
The ultimate in mechanical grip. The Brabham BT46 wants to know where the large cooling element fits into this equation.
that's aero grip
Fantastic, This is exactly what I was hoping for after the last one. The idea of making a mechanical system like that in my shed is interesting. The hardest part would be getting the dampers tuned for such an odd project.
This is amazing.... people already run air suspension on cars for looks; this could be a real game changer for performance. Nice work
positive algorithm engagement comment!
This is all class. Stuff I've always had a vague idea about is now perfectly clear and so logical. Thank you so much.
I've always been curious as to what aero modifications you would do to a regular street car, such as a 350z or BMW 3 series, for making a fast track car with no restrictions. So doesn't have to meet any regulations. Can we get a video on that and the restrictions you'd have to overcome?
I love it, awesome.
Thanks for the upload!
Pro and clear, great lesson!!!
I've been thinking of this exact setup for years(didn't know it existed already) and always wondered why I haven't seen in on the market :D
is already on the market, with mclaren supply by american company tenneco. previously was brillianty use by citroen with their hydroactive system
congratulations, you have sucessfully made the suspension system of the citreon 2cv
He could have given that example, but the 2CV doesn't have the functionality desired.
Love the vid but one thing on the video production. You have a very low frequency hum you might want to look at. Its very noticeable with headphones and a little distracting at times
fantastic video as usual
Interesting. Very interesting.
It's the ultimate in mechanical grip as far as keeping the tires on the ground, but this video says nothing about the geometries of the suspension arms and steering which maximize the contact patch for the various loads and conditions they'll be facing. To that effect, I'd like you to do a video on slip angle and camber vs contact patch and load. Particularly for the rear suspension as I believe that a specific forgotten technology (the de-dion axle) can provide a massive benefit at the rear of a car for a driven axle.
However, I also believe beam axles in general have the potential to provide benefit regardless of what end of the car they're on or whether or not they're driven. It's just that on the steering axle, you have to worry about packaging and the steering mechanism itself, more. In a short-travel suspension you could just put the steering rack ON the axle itself, but on a mid and especially long-travel suspension (and/or if the driver/steering shaft line is massively off-axis of the steering rack) it becomes a much more difficult question.
Also, can't you tune pitch stiffness through suspension geometry anti-properties like anti-dive and anti-lift?
Subscribed immadietely
That was excellent, keep up the good work!
Warp effects can be largely negated by having the roll axis inclination and the mass centroid axis, broadly speaking, parallel. This results in the roll couple being equal from front to real. From a driver stand point, this generally makes for a car with a sound base of balance (and very responsive to balance changes). This may not be the path to ultimate grip, but if the car lacks balance then the driver cannot access the extra grip and it is all for naught.
Very interesting, great video!
I'm not understanding your hydraulic drawing. Doesn't the heave circuit equalize pressure between all four wheels, and therefore you don't have any roll or pitch stiffness?
After watching AMZs video their hydraulic circuits do not share fluid between different wheels so it makes sense now.
He talks about the need to fix it to remove "weird hydraulic interactions), but you're right - as it is illustrated here it just wouldn't work.
Excellent video! Can you do one analyzing the new 2022 F1 cars aero?
Excellent explanation. I'd love to try building something like this when I'm designing in fsae. Looks hard to package though. With the electric motors I think a direct acting system would be easier to package than a bellcrank system. Still have no idea where most of it would go though.
I heard that f1 cars run torsion beam springs for their compactness and weight. Was that a last gen thing, or still used?
I think they started using it quite a long time ago and they still do.
Yeah, but that's prolly gonna change in 2022 with the tiny sidewall height tires
They used it to dampen the nose movement, but will get banned.
@@Sysiphus1981 why would it get banned?
@@fillman86 ruclips.net/video/t58qjcNwEbo/видео.html
I watched this video with the application on a formula student car in mind but thought it’s overengineered or to expensive but mentioning the amz have me hope to maybe building this into a formula student car
Damn. Saved
EV motors on all 4 corners right? And this suspension setup is how it should be rt?
At 1:28 you say we can’t do anything to tune pitch and heave except by changing stiffness. What is the impact of anti dive and anti squat geometry then?
Hello KYLE! I think it would be cool if you made "the ultimate in aerodinamics" , pointing what would be a picture perfect setup. Covering body sape of the car and accessories. Thank you!
To control pitch, why not just use adjustable antidive geometry like in NASCAR?
Thats something that I have never seen before. Amazing to me. Do F1 cars use any of this?
Great video
I love this!
This suspension system has more pistons than my engine. :D
6:40 nice stagger. This must be a dirt track car.
There's a concept I've always been curious about, but I've never seen anyone really cover the suspension, geometry, and tire dynamics of it, a leaning quad with a low cg cockpit; essentially combining the leaning characteristics of a motorbike with the steering characteristics of a four wheeled vehicle. One specific question I've always had is about the leaning of the various components, say if the body of the vehicle leans to a specific degree, do the inner and outer wheels lean to the same degree, or should there be some kind of differential between the components where it's inner wheel has a greater angle of lean than the body and the body also has a greater angle of lean than the outer wheel, x>y>z, all from a reference of a straight up and down 90°; a leaning variant of ackermann geometry, essentially. Another specific question I have pertaining to this is how this leaning would interact with steering, such as if ackermann geometry is still relevant, which of lean and steering is more important, etc. Then after those two, assuming both are equally important, and if leaning does have it's own analog of ackermann geometry, how this would incorporate into a suspension system, specifically an independent leaning suspension.
I have yet to find anyone actually research this kind of concept. The most I've found are leaning trikes where performance is an afterthought. But my curiosity is if this kind of concept were thrown into a motorsports category where everything is fine tuned for performance.
Great video what software are you using for the 3d design?
I'd love to see a really cool design build in bricks :D Maybe part by part just the suspension. Another part could be the steering, maybe with DAS. Another would be engine and radiators. And the last one just some nice cosmetics. To finally have a reall nice brick car that has all the important features. Maybe even gears and shift :D
Wow unexpectedly complicated set up!
Isn't all this the twist soft suspension following the concept used on train carriages, all this was in racecar engineering magazine like 20 years ago
What a FRICen system.... :-)
You forgot to discuss hydraulic fluid density and temperature changes.
Great vid and explanation as always. Is this more or less what McLaren was going for with their hydraulically linked suspension on the 12C?
Jesus Christ a computer controlled active suspension would be not only MUCH effing easier but way less complex and cheaper. Thanks Bernie and the boys from 1993…
That´s crazy. I think that the hidraulic flows slowly, (you can use other liquids that flows better) i think that a pneumatic suspension with some electrovalves and a shock asorber can do that. An individual suspension without roll, pich, but never forget the most important part. The suspension desing, you can use a good suspension elements but if you use a torsion bar instead of doble whishbone or multi link the resuslt won´t be the best.
I am intrigued how williams did in f1 in 1991 to control the suspension, there ins´t any information.
PD: I have a citroen bx that was from my uncle, and most people thinks that is awesome, but in my opinion the suspension is bad, dont get me wrong. when i fist drive the car, i was in a small city and i thougth, oh the road is very nice and flat, but in reality, there arent. The suspesion is the soft suspension that i drove, but it feels very, very stiff because you goes every time really FLAT, is realy independent and self-leveling (the leveling is slow, like 0-5/1second) The shock absober(spheres) and hidraulics are the best. But the problem is that in the rear the car uses torsion bar and this ruins the setup, some roll and pich... For example bmw. are cars with a setup with little dive and squat, and roll. The most important is the GEOMETRICS
The hydraulic fluid won't have to flow very far and you want hydraulic fluid as you want to keep the expansion of the hydraulic lines down as the system would be harder to predict the needed spring rates. And possibly by the time the air starts to create enough pressure to move the piston it's too late. In sense the air is a spring and you don't want that, same as expansion of the hydraulic lines. You could possibly use valves to control the hydraulic fluid flow but it would lead to minimal gains if any. Active shock absorbers on each individual piston setup would be best but it's unclear how much of a gain it would give. Your are correct that suspension design is the most important thing but a torsion bar is just another spring and they use them in F1. You should have said torsion beam suspension which in that case you would be correct that it is not ideal. Williams has kept their suspension a secret in case active suspension resturns in case you didn't know and that's why there is no info on it. Some people believe it's close to what is called the FRIC suspension which was used until 2014.
Please leave what you would like me to do a video on next. 3 videos now askin for turbo fans
In sailboats we shift the weight. I know some cars were designed to shift weight into the corners. Was this outlawed in F1?
This is him describing the Merc cheat suspension without using the words "Active Suspension"
Isn't that similar to McLaren 650S or 720S suspension setup?
as far as I know they have no interlink front to rear, and basically just use the hydraulic system as an anti-roll bar.
yes and no as its not near as complex, if im correct they only connect the front and rear for pitch control. they also use valves at the top and bottom of the wheels dampener. the mclaren setup still doesnt control heave or really anything independently. he has a vid on his channel about the 720s suspension
@@jacksonblanks8038 thank you for clarification. I drove 720S, its ride is smooth as butter, nevertheless 😉
@@bartekb5074 yep it's suspension is very good for a road car. If possible try driving a real professionally built race car. There is nothing like it
@@jacksonblanks8038 I would love to!
Could you do a video on Ultimate Mechanical Grip: Solid Axle version?
I would replace the hydraulic system and use lineare electric actuators. Benefit would be softwaredefined filters and energie harvesting.
that is gonna introduce active suspension system. the hydraulics system is reactive
instead of messy hydraulic..
how about electromagnetic suspension? basically something like this but replace the pistons with electromagnets, then send the data to the CPU, process the modes individually, actively manages the displacement data, then send feedback to each suspensions. ultimately creating an active suspension.
Bose has done this before. They found that, while the ride quality of the car was amazing, it would be too heavy, too inefficient, and too costly/complicated to realistically implement in a car.
The electromagnets would have to be quite powerful, meaning that they'd draw a lot of current. Maybe it could work better with assistance from some other device.
I suspect this makes active suspension look like a fairly simple system.
Maybe I'm just being stupid but if hydraulic fluid is incompressible, wouldn't this system not just immediately seize ?
Under heave the pitch &roll circuits would seize, under roll the heave and pitch circuits would seize and etc.
My guess is there would need to be compressed gas reservoirs at both ends to accept the necessary displacement ?
You get your "head space" in the heave piston, which can always move up and down. All the other pistons lock up by design when they are pressurized on both sides, that's what allows each one to control only one mode: they will only move for the mode that creates unequal pressure in that piston. You don't want, e.g., the pitch piston to move under heave, you want 100% of that motion controlled by the heave piston alone. Under pure heave every other piston will remain stationary.
I love this, but tires make the biggest difference, you should make tire types clear.
Then again my TT has the worst warp🙃🙃🙃
That tbar is ridiculous you should have a hydraulic system similar to KDSS
Whuuut? So better than leaf springs? I might have jumped in at the deep end.
Did you choose the advertisements?
Not as erosive as others.🎅🏻🇦🇺😎🍀
Why the flat yellow lines on the tire?
Current F1 tires say Pirelli horizontally, not in an arc.
What would happen if going through a hard right turn you ran over a curve with that right tire? The right front tire will compress and the left rear will lift? This would cause the rear right to drop and the left front to raise. Now if this was instantaneous it seems like it would work. But real world the potential delay between front and rear would seem that would raise concerns. That is of course with no failures in any point of within the system due to uneven seal wear or fluid viscosity changes at different temperatures as one corner is worked harder then the others.
It would be tuned accordingly. So the damping and spring affect between the corners could be relatively light. It all depends on the type of car and conditions. I very high cog vehicle on rough terrain would benefit the most. I’d like to see a baja race car with and without it compared.
Correct me if I am wrong but is this like the FRIC suspension system that was banned by the FIA for F1 a while back?
Is it possible to do it now all electronically. i mean using sensors and actuators. this saves on oil spillage and one can competely configure the system by means of SW and adapt it dynamically and based on the terrain conditions and needs.
yes, the Williams f1 car from the 90s is a good example of this but be aware pretty much every other team who try doing this cost the driver their lives.
Can you do an aero or also suspension analysis on the GTWC cars?
So like 488 gt3... and other GT3...
Maybe with a comparison of each one...
Thanks... and sorry for the bad english:):)
would it make sense to have a dumper in the mid instead of just a rod? For example, a car goes through a hill climb? Is it a dumb question? It's soo custom.
Now, if only some could put a pump and some valves in the system you could control the suspension for every bend ;)
on a serious note, I thought that connecting the front and rear suspension was illegal in F1. I also thought that using hydraulics to connect the wheels was also band?
it was banned around 2014. look at what is called the FRIC suspension
So is this a form of active suspension?
No, its totally passive. Active suspension had a pump that added energy to the system/fluid to control the attitude of the car. This is a passive system, the car still rolls and pitches as if it had springs, we are just using the hydraulic fluid to carry and/or redirect the loads going through the suspension.
Now I feel bad for my design for a suspension of a solar car hahaha,as I only have time to design the front I cant control the roll nor pitch of the entire car.
Could you explain how the suspension is attached to the chassis? I know flexure joints are being used instead of ball joints. But I wonder how they are mounted an stuff
1) on a non aero car, would there be no need for heave control? so if you ran a T-bar setup you could tune your pitch characteristics freely using the "heave"/pitch spring and damper?
2) for a road car do you think a hydraulic piston actuator for the decoupled mode suspension would be easier to package than a cantilever and T-bar setup? the reason I'm asking is because it seems like you can move the springs and dampers to anywhere in the car instead of having components that require a fixed position and geometry near the wheels.
3) would a single piston with a single hydraulic line be sufficient to control each wheel? does anyone actually do this on a 1000kg+ car?
4) implementing this system with air springs and adjustable MRF dampers would be super cool. would there be an disadvantages to this other than complexity?
1)the heave would still be ideal to in essence carry the cars weight. 2) it would be the same size to package as a conventional setup around the wheels but you are correct everything else can be moved around where there is space but it is best to minimize the length of lines as you would have less control from the expansion of lines.3) yes a single hydraulic piston of sufficient size and rated for the forces is all you need along with one line that would go to a distribution module where the other lines would be connected. so you would only have a single line from each wheel and then close to the pistons you have the distribution blocks where you would have mess of hydraulic lines to the proper pistons. currently only prototype vehicles use this as no professional series allows it and it is just too untested and costly for a road car as of right now.4) assuming you are using air springs and dampeners on the pistons it would just give you a different characteristic but i would be cautious of excess heat messing with your spring pressures. in sense regular springs are linear and follow F=K(x) where f is the force needed to compress X distance and K is the spring coefficient. Air follows a different trend where is easier to compress at first but as the pressure increases its spring coefficient dramatically stiffens. on a road car its better to stay with normal springs as they are easier to predict, but air suspension is big in off road where you want the wheels to articulate easily at first and to get much harder as they come to the end of travel so you don't bottom out. suspension geometry also does this especially using a cantilever suspension as the angles of the pushrod and the dampener can change the forces acting and being acted by the wheel. This is where you spend millions in engineering.
Awesome but isn't this all illegal on the new cars?
so that's what Mclaren road cars uses and what merceddes F1 use to have right? that hydraulic system without the warp hydraulic circuit
No.
Ooooooh shit this looks like its gunna be interesting
could u talk about the long piston of ETH Zürich?
Do you have any particular opinions between controlling dive and squat via spring systems vs. geometry (anti-dive and -squat)?
hard to change up suspension mounting points mid race plus it puts more force on the suspension pickup points. best to us spring systems but if you cant then use geometry
Whats your take on the 2022 F1 aero?
is it just how F1 FRIC work?
does this setup still need normal spring on sock?
did the pitch need spring?
AFAIK, FRIC isn't fully mode decoupled.
@kyleengineers would it be possible to flip this design and run the push rods under the seat of a center seated car? It imagine it would require flipping the suspension pushrod as well, attaching it to the top control arm and the rocker, shocks and springs attaching to the bottom frame.
...I quietly wonder if there'd be any point to running a hydraulic system like this in something with a lot of travel. like...30" of travel or more, attached to 66" tires. The "hydraulic pistons" are already there in the form of the nitrogen gas shocks the big trucks run. Main thing would be keeping all that oil cool (and in the lines) through the 2 or 3 minutes of a freestyle...
...thinking about it, fully decoupled suspension is probably way too sophisticated and expensive for Monster Trucks. But it's interesting to think on nonetheless.
If I had a whole lot of money I would love to try a system like this on my race buggy, have it all coming back to a central unit that could then have a full on cooling circuit with a radiator to keep the whole thing cold! One day someone will develop it...
@@KYLEENGINEERS At least aspects of it, sure. Tying the front and rear shocks together for pitch control would definitely help a lot of the off-road racers, since with the soft springs they really squat and dive. Warp maybe not so much, guys like the articulation for the uneven surface, though separating that from roll control would probably be a good thing. Who knows?
The super high CG of monster trucks makes it kind of an ideal application for some sort of front/rear interconnect. I don't think it would worth going full decoupled but there's plenty of space for a bar running front to back that could give some real benefits in squat and dive.
what prevents the fluid short-circuiting through the shared sides of the various pistons?
the fluid doesn't actually flow into the same reservoir in each cylinder, they are separated, i.e. you might have a cylinder with 4 chambers, pairs of 2 chambers are connected and each pair works against the other
@@bilaltariq7819 thanks!
Jesse, is that you? did you sell the Jetta?
Hi Kyle. I was wondering where the forces from those four decoupled mode dampers go? They would be mounted directionally in the chassis somewhere to use that force to help the car? Can you illustrate that please you make me want to design a car!
They would be mounted to the chassis. I'm surprised I haven't seen anyone mention this, but Mclaren uses a VERY similar setup on their cars that are above the sports series (like the 720s). Many people say in comfort mode that it rides almost as smooth as a Rolls Royce, and stiffens right up whenever it's in track it sport mode. You can check out a video made by engineering explained where he explains it in detail.
I didnt get it. Only one rod connecting the wheel to the system: how would this wheel not pitch yaw wobble…
Does the motoGP holeshot device work in this idea?
Holy shit, this is mind blowing
nice system. can it be used for off road vehicles?
Probably warp is beneficial for off road axle twist, and the pitch control and roll control would greatly benefit such vehicle on road driving dynamics to improve braking and cornering.
Does f1 allow to connect front suspension to rear suspension
Yes and no. It's not prohibited but the best ways anyone has thus far come up with to do it (hydraulics) have been prohibited.
Would this work with a hydraulic link instead of a mechanical one for the front/rear linkage?
I would recommend the second half of the video
@@hunterhach7533 sorry, watching from offshore and only managed to get the first few minutes - 144p…
@@smellysam oh goodness, yes it can! :)
Cant u achieve all this with electronic active suspension?
Would fancy ferromagnetic shocks make all this cross plumbing unnecessary?
No. They are only dampers. Dampers can only affect transient response.
AS sure footed as CAT!