Pilot Suspension / Adaptive Damping: Operation

With all the techniques intended to improve and perfect the suspension of our cars, there is something to get lost... Here we will see what a so-called controlled (or adaptive) suspension means, a system more widespread than active suspension (pneumatic, hydropneumatic or even hydraulic with Mercedes' ABC suspension) because it is cheaper to produce.

More precisely, it would be more accurate to speak of controlled damping because it is the shock absorber pistons which are under control here, and not the suspension (springs). However, knowing that the shock absorbers "control" the suspension (speed of travel from top to bottom), we can indirectly say that it is a controlled suspension... Those who do not have much knowledge about suspension must go take a look here.

Also note that controlled damping can be fitted in parallel with air suspension, and that this is often the case at the top of the range. These two systems are therefore not opposing each other (pneumatic springs and controlled shock absorbers) since they can work together and each have a different role.

A little reminder on what a shock absorber is

A shock absorber is a piston made up of two oil-filled chambers. These communicate through small orifices/channels in which the oil can circulate (from one chamber to another).

Their role is to moderate the speed of travel of the running gear, because the spring is not exemplary in this area... It must therefore be understood that they do not carry (suspend) the car but act as policeman in terms of speed. of travel.

Let's take a simple example: the bicycle pump. The latter is made up of two parts nested like a piston. So I can go back and forth without any problem, like with a shock absorber. However, if I want to accelerate the pace, I realize that I cannot go too quickly because it still takes a little time for the air to escape (the phenomenon is all the more important when I inflate my wheel). So there is a little resistance that occurs when I start to go quickly in terms of back and forth.

Well the shock absorber does the same thing except that here, in the case of controlled shock absorbers, the resistance can be modulated. Let's look at some techniques that allow you to do this.

What can an electronic suspension do and what is it for?

Beyond being able to adjust the suspension setting and therefore to adapt the comfort, the electronic system takes the opportunity to go much further ... In fact, being able to change the damping laws of each of the shock absorbers in a fraction of a second makes it possible to a lot of things ...

Here are the main ones:

• In bends, the suspension calibration becomes rigid on the side which crashes in order to limit the crushing of the car on its supports. As a result, the car will tend to limit pitch and roll.
• On degraded roads, the system softens and stiffens each shock absorber several times per second. As a result, thanks to a computer, the shock absorbers are adjusted on the fly to limit jolts and body movements up and down. Moreover, everything is done to keep the car as much as possible with the famous Skyhook effect.
• Safety is increased in the event of sudden avoidance-type maneuvers. ESP and ABS work with the suspension to further optimize the way the car will behave. The system therefore makes it possible to change the damping law according to the level of depression of the piston. If, for example, I am closer to the stop, it is preferable that the damping stiffens even more. In short, the progressiveness of the damping can be modulated and controlled on the fly, depending on the situation and the level of crushing of the suspension. We are then dealing with an intelligent suspension which reacts according to the context, and not a passive device which always reacts in the same way whatever the conditions.

Examples

As soon as one of the wheels "hits" an imperfection, the system reacts to the quarter of a second to adapt the setting of the shock absorber. Here, the system softens the shock absorber so that you feel less of the bump. However, if the latter is too big, the damping will be stiffened before you hit the stopper. The car will then still be shaken, but there is no real choice if you want to avoid breaking something.

Magnetic controlled damping system

You will have understood, the goal here is to be able to modulate the resistance of the travel of the shock absorber piston by modulating the flow of oil which goes from top to bottom. The more we limit it, the drier the damping.

Here, the engineers were very clever (as they often are) since they had the idea of ​​adding magnetized particles to the oil. Thanks to electromagnets (magnet which is activated by electricity) placed in the circulation channels, the speed of the flow can be adjusted. The more juice there is, the more powerful the magnet, which will have an even stronger influence on the particles present suspended in the oil. The diagram below illustrates this.

The alignment of the magnetic particles makes it possible to block the pipes to a greater or lesser extent, and therefore to make the piston more or less rigid in terms of travel.

Adaptive damping system by valve

The principle is the same except that here we do not modify the fluidity of the liquid thanks to metal particles. In fact, it is simply a matter of controlling small valves placed in the circulation channels. It is therefore quite simply a matter of opening or closing small taps more or less.

Several provisions exist, as always ...

The flow rate is effected by the compartment on the left. Part of the oil passes through it and it suffices to integrate a system of valves to modulate the speed at which the oil can pass from the bottom to the top.

This time the valves are integrated in the shock absorber piston. I remind you that they are controlled by electronics even if this is not clearly indicated on the diagram.

Your reported issues

Here are testimonials taken automatically from opinions posted on the site's test sheets.

Ford Mondeo 3 (2007-2014)

2.0 TDCI 163 hp manual gearbox 6, titanium, 268000 kms, 2010, 17 ″ alloy rims, sunroof, GPS, touchscreen. : shock absorbers piloted to be replaced "not given", But necessary. Purchased with 268000 kms, a loose injector joint, replacement of the 4 joints, I take this opportunity to redo the complete distribution with water pump, as well as the accessory belt and the rollers, plus the oil change, for 1200 €, with a big problem with extracting an injector, I find the bill very reasonable. shock absorbers should have been replaced by the seller, a garage, but not having available availability, I hope he will keep his word.shock absorbers piloted

Audi A7 (2010-2017)

2.0 TFSI 252ch S-tronic box, 27.000 kms, 12/2017, 255 R18, SLINE : podcasts piloted - I had to change the 2 podcasts rear after 30.000 km (in 06/2021, a little more than 3 years after the purchase) because they have become porous (message displayed: vehicle too low. Restricted ground clearance)

DS DS7 Crossback (2018)

2.0 BlueHDI 180ch 100000 : I have 1 new DS7 which now has 100000 kms and only problems since the purchase 😡 Camera problem, water leak, racket kick with controlled shock absorber Do you have collective contacts Thank you

Renault Talisman (2015)

1.6 dCi 160 ch EDC Initiale Paris Gris Cassiopée - 2016 - 100km : o HS battery after 3 years —> Use of EFB technology instead of AGM while the car has kinetic energy recovery when braking. o Faulty lumbar adjustment after 3 years o Right rearview mirror which adjusts by itself with unusable reversing function as well as the memory function o Steering wheel which wears out prematurely (4 years) o HS engine after 90km o HS gearbox after 000km o Central armrest lock broken after 92 years o Driver's seat pressing on the central console resulting in wear of the leather while the passenger seat is spaced from the console.

BMW Series 4 (2013-2020)

435i 306 ch XDRIVE M SPORT BVA8 Steptronic 98000km 2014 : — Right rear noise in the lower part of the car on small deformations in the road, like silent block (not on a donkey for example) never resolved by BMW in 3 visits. - Multimedia system fails from time to time when a USB key is put on (very random) - Rear light, the connector burns regularly, a known disease since BMW sells a KIT for 10 euros to repair the connector. - Pulls excessively to the right, problem with podcast piloted + Xdrive, without solution

Renault Megane 3 (2008-2015)

1.2 TCE 130 ch Manual Gearbox 6, 56000 kms, 2014, Estate, Bose finish 1.2 TCE 130 Eco2 : Megane 3 Estate 1.2 TCe 130 of September 2014. => Never overconsumption of oil in 56000 kms, but many other concerns related to the subject of engine failure - 01/2015 - 4 kms - Declaration of a problem with vibration around 299 rpm in gas retention + metallic clicks >> RAS for the Garage - 3000/09 - 2015 Kms - Re-Declaration of a vibration problem around 14 rpm in gas retention during the overhaul . >> Fault finding >> Replacement of Transmission Bearings = Not solved

>> Gearbox replacement = Not solved

- 02/2016 - ~ 21 Kms - We insist on finding a solution. Arrival of “specialists” from the seat to test the car. According to them it came from podcasts… a real joke! >> Passing the vehicle on a dynamically bench to try to find where the noise is coming from >> Replacement of Piloted DumpValve = Not solved

>> Passage of vehicle on bench dynamically to try to find where the noise is coming from >> Replacement of DumpValve Controlled = Not solved

>> Replacement of Chain + Tensioner Kit = No rattling or vibrations - 06/2017 - ~ 33 Kms - New vibrations around 000 rpm, but no clicking - 3000/04 - 2018 43 Kms - Return to car dealership new timing chain slamming >> Replacement Chain + Tensioner Kit = No slamming but vibrations still present - 921/09 - 2018 50 Kms - Service at the dealership which adds too much oil (653 mm above the maximum when cold)> > Request for removal of excess oil - 3/04 - ~ 2019 kms - “Engine Breakdown Risk” warning light with oil pipette on when the engine speed is maintained above 55 rpm for several minutes. >> Reprogramming by RENAULT = Not solved

Alfa Romeo Julia (2016)

2.0 Turbo 280 ch : Failure of podcast pilot this will do 2 times in 2 years

Renault Megane 3 (2008-2015)

1.2 TCE 130 ch EDC - Bose - 2015 - 80 km A: Engine replaced at 37 km, very high oil consumption, low distribution noise. 000% supported by Renault and 90% by the dealer where I just bought it 10 months ago. The battery is discharged after driving 1 km on the motorway. It is necessary to check the electronic control of the generator. Air conditioning noise from gas circulation and condenser freezing after several hours of continuous operation. No solution... After replacing the engine, the front parking sensors often work for no reason. Solved after checking the beam. It must have been incorrectly assembled when the engine was replaced. Cracks on the left edge of the driver's seat are a common problem with this faux leather upholstery...

BMW X3 (2010-2017)

35d 313 hp BVA 8, 95000km, year: December 2011, Sport Design finish with piloted suspension, Sport steering with variable reduction : A design (or construction) defect affects the steering rack which has already been replaced 4 times. My car is currently immobilized at the dealership who declared it "dangerous", pending a decision from the manufacturer. Towards a 5th change of rack?… At 65000km, the car was reset at the technical control 25% of efficiency of the AVD (piloted) shock absorber. So replacement of shock absorbers AV and obligation of reverse inspection. In the defense of the manufacturer, I specify that all these repairs were made 100% by BMW (parts and labor) with free provision of a replacement vehicle; even well beyond the legal warranty period (and the extension to 4 years that I had subscribed) because the problems appeared when my X3 totaled only 20000km… Today I am awaiting a last technical inspection of BMW for a final repair or outright replacement of the vehicle in which I have lost confidence. I a posteriori a shiver in the back at the idea of ​​having driven at 240 km / h on the German highways a few months before being informed that the direction of my car was dangerous… In the absence serious technical or commercial response from the manufacturer, I plan to have recourse to the Courts ... The "Pleasure of driving", the slogan of the propeller brand, was not present because of these repeated malfunctions leading not only to incessant round trips to the workshop but also to a real loss of pleasure and even becoming anxious. The rack is one of the main "black spots" of this vehicle and the

Skoda Superb (2015)

2.0 TDI 190 hp dsg 185000 km Nov 2015 style; Parisian taxi use : starter at 70000 km flying engine at 120000 km engine light on fap to change approximately 3000 euros of estimate battery and triangles of podcastfuel pump steering gear 1600 euros in parts distribution 1000 euros engine support on the silent side of the cradle block of the cradle with obligation to disassemble the cradle 700 euros of labor rear right door handle inside broken (the handle is not sold at retail obligation to change the door panel full interior 600-700 euros) 4 shock absorbers piloted changed because they were fleeing 1500 to 2000 euros in costs

BMW Series 5 (2010-2016)

520d 184 hp Auto box year 2011 17 ″ Touring rims 210000kms : Except for the podcasts rear, no worries except a problem of opening the trunk guaranteed (2x) podcasts dangerous tires (every 90000 km, the cushions explode) This is a construction defect that the manufacturer does not want to accept. The first time replaced in warranty after having literally exploded out of a long curve at 200km / h !!! Fortunately, having notions of piloting (competition kart), and the empty highway, I was able to control my exit on along the rails. It surprises all the same. there were 8 identical cars with the same breakdown awaiting parts (out of stock) at the dealership. 90000kms later, ditto, but driving gently. This is unacceptable.

Mercedes GLC (2015)

350e Hybride 320 ch 02/2017 8000 kms : battery warning at 7800 km on the instrument panel then impossible to restart for 1/2 hour Without doubt a software bug. Snap podcast at the rear left (undoubtedly podcast piloted tire) disappeared after 7000 km

BMW X5 (2000-2007)

3.0 d 218 ch BVA 135000 KM END 2006 FULL OPTIONS : podcasts piloted. Electronic. Sunroof . Smell of exhaust gas in the passenger compartment

Peugeot 407 (2004-2010)

2.7 HDI V6 204 hp 30/2008, 102000km, Féline : replacement blackout blind for the panoramic roof (68000km), pneumatic pressure sensor (69000 km), dual-zone air conditioning flaps unit (75000km), both podcasts rear driven (90000km), faulty MP3 (90000km), accessory belt tensioner roller (92000km), glow plug broken in the cylinder head during their replacement (100000km) and finally 102000km engine out of order, engine replacement estimate 9000 € HT and excluding hand of work !!!! and never any participation from Peugeot despite regular maintenance in dealership !!!!

Mercedes CLS (2004-2010)

55 AMG 476 ch 110000, 2005, AMG : The 55 AMG is a very strong engine I reprogrammed it to 540hp and unbridled speed and no problems to report, it is the airmatic the big black point of this kind of car (the podcast driven and its setbacks), but on this model the problem is really felt around 150km and for the moment I already have signs of fatigue. Braking is powerful and relatively durable (on the road), however replacing it costs a good 000 euros minimum. The tires are changed every 2000 km in sporty driving.

Peugeot 407 coupe (2005-2011)

2.0 HDI 163 170000, 2010, GT : depreciation piloted (under warranty)

Audi Q7 (2006-2014)

6.0 TDI 500 ch 110000, 2008, OLD : Small update of the box, high routine maintenance, podcast pilot who suffers.

Mercedes ML 2 2005-2011

63 AMG 510 ch 143000, 2008, 63 AMG : the 7G gearbox has trouble finding the right gear on the motorway (the torque must be too high for the gearbox) and this crap of podcast piloted which gives up the ghost around 120km a well-known defect which always has its small effect in the maintenance budget (counting more than 000 euros without MO), the 2000 AMG costs an arm to maintain unlike the 63 AMG.

Audi A4 (2001-2007)

RS4 420 hp 86000, 2007, RS4 Avant : clogging of the cylinder heads due to direct injection which degrades the power (almost 20% loss of an RS4 rarely comes out more than 380hp real original!), manual transmission problem, transmitter and clutch receiver, several leaks on thedepreciation controlled DRC (dynamic ride control), shock absorbers fragile in sporty driving (2260 euros for shock absorbers out of MO)

BMW Series 5 (2003-2010)

525d 177 ch 128000 kms, 2005, Excellis : 3 major problems encountered in 90000 kms 1- HS damper pulley (hs air conditioner belt, hs alternator belt) at 111000 km, with immobilizing vehicle failure when returning from vacation. Cost 1400 € with battery change. 2- Compressor of podcast rear (Touring E61 model) at 121000kms. Vehicle rollable but at very low speed (more than podcast) Cost 1000 € 3- CCC HS module at 126000 kms (controls the radio, the on-board computer, the GPS, etc…). Vehicle rollable but reduced comfort… Cost being processed…

All comments and reactions

Dernier comment posted:

luckygkiller (Date: 2020, 11:02:17)

Hi,

I have a tapping in the center console of my 6 audi RS2015 560hp when I accelerate suddenly.

This tapping eventually deteriorated the center driveshaft that I replaced but this tapping persists and I think the driveshaft will damage again.

However, it is less strong since I changed my rims fitted with my winter tires.

The problem would probably come from the piloted suspension and would be known on the RS6….

Can you give some information?

Thanks in advance.

Luke

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Are you in favor of restraining cars at a speed of 130 km / h?