Mysterious Change to Active Curve System?
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2013 ML550: Paladium Silver, Brown Satin Ash
Mysterious Change to Active Curve System?
Has anyone noticed that the description of the Active Curve System has silently changed? Or is it just me?
In the new descriptions I'm finding online, Active Curve no longer decouples anti-roll bars on and off to create stabilization, it instead uses a hydraulic pump from (what I assume) the AIRMATIC system.
While they removed the Active Curve System description entirely from MBUSA's ML web pages weeks ago, the MBUSA AMG ML63 still describes the Active Curve System. But I swear it's now different...it just talks about 'variable front and rear stabilizers" and nothing about anti-roll bars
The old description of the Dynamic Handling Package and how the Active Curve system decouples anti-roll bards for both on and off is still described in this German MB tech center website:
http://www3.mercedes-benz.com/mbcom_...ystem/function
"ACTIVE CURVE SYSTEM boosts driving comfort significantly:When cornering, the stabiliser bars are actively impacted and keep the torsional moment constant. The roll distribution is variable to enable the vehicle to be adapted to almost any situation. The driver has the feeling of gliding on rails, particularly in vehicles with a high centre of gravity. In off-road environments, the system guarantees improved axle roll by decoupling the two stabiliser bars at the front and rear axles."
Car & Driver also wrote about the 'anti-roll' bars in this old review:
http://www.caranddriver.com/reviews/...t-drive-review
"That $5150 option includes the Active Curve System (ACS), which decouples the anti-roll bars both off-road and during straight-ahead freeway slogs."
However, this newly update European site now also describes the Active Curve System in a new way: http://www.mercedes-benz.com.cy/cont.../chassis.html#
"ACTIVE CURVE SYSTEM
The ACTIVE CURVE SYSTEM, also called roll stabilization, reduces the vehicle’s roll angle when cornering or driving off road by using its active suspension stabilizers. This enhances ride comfort for the vehicle occupants and boosts driving dynamics off the road, at medium speed (winding rural roads) and also at high speed (motorway). The ACTIVE CURVE SYSTEM determines the roll forces acting on the vehicle by means of pressure sensors in the front and rear axle rotary actuators and a lateral acceleration sensor. An electronic control unit then sends actuating signals to the valve blocks on the front and rear axle, thus controlling the oil flow in the system produced by the hydraulic pump. The pressure in the chambers and the configuration of the active suspension stabilizers mounted on each axle are then adjusted to the driving situation."
So, the question is: Did MB really change the Active Curve System recently? Is this why they suddenly stopped offering it in the ML-class (except for the AMG ML63)? They said it was a parts shortage. Has this led to a re-design? Or is there something wrong with the anti-roll bar design? Did it not work well enough? Was it too expensive to implement?
Or am I'm reading this all wrong? Is "active suspension stabilizers" the same thing as "anti-roll bar?" But if so, why are they no longer talking about how these are 'decoupled?' Instead, it reads like the AIRMATIC system is being used.
In the new descriptions I'm finding online, Active Curve no longer decouples anti-roll bars on and off to create stabilization, it instead uses a hydraulic pump from (what I assume) the AIRMATIC system.
While they removed the Active Curve System description entirely from MBUSA's ML web pages weeks ago, the MBUSA AMG ML63 still describes the Active Curve System. But I swear it's now different...it just talks about 'variable front and rear stabilizers" and nothing about anti-roll bars
The old description of the Dynamic Handling Package and how the Active Curve system decouples anti-roll bards for both on and off is still described in this German MB tech center website:
http://www3.mercedes-benz.com/mbcom_...ystem/function
"ACTIVE CURVE SYSTEM boosts driving comfort significantly:When cornering, the stabiliser bars are actively impacted and keep the torsional moment constant. The roll distribution is variable to enable the vehicle to be adapted to almost any situation. The driver has the feeling of gliding on rails, particularly in vehicles with a high centre of gravity. In off-road environments, the system guarantees improved axle roll by decoupling the two stabiliser bars at the front and rear axles."
Car & Driver also wrote about the 'anti-roll' bars in this old review:
http://www.caranddriver.com/reviews/...t-drive-review
"That $5150 option includes the Active Curve System (ACS), which decouples the anti-roll bars both off-road and during straight-ahead freeway slogs."
However, this newly update European site now also describes the Active Curve System in a new way: http://www.mercedes-benz.com.cy/cont.../chassis.html#
"ACTIVE CURVE SYSTEM
The ACTIVE CURVE SYSTEM, also called roll stabilization, reduces the vehicle’s roll angle when cornering or driving off road by using its active suspension stabilizers. This enhances ride comfort for the vehicle occupants and boosts driving dynamics off the road, at medium speed (winding rural roads) and also at high speed (motorway). The ACTIVE CURVE SYSTEM determines the roll forces acting on the vehicle by means of pressure sensors in the front and rear axle rotary actuators and a lateral acceleration sensor. An electronic control unit then sends actuating signals to the valve blocks on the front and rear axle, thus controlling the oil flow in the system produced by the hydraulic pump. The pressure in the chambers and the configuration of the active suspension stabilizers mounted on each axle are then adjusted to the driving situation."
So, the question is: Did MB really change the Active Curve System recently? Is this why they suddenly stopped offering it in the ML-class (except for the AMG ML63)? They said it was a parts shortage. Has this led to a re-design? Or is there something wrong with the anti-roll bar design? Did it not work well enough? Was it too expensive to implement?
Or am I'm reading this all wrong? Is "active suspension stabilizers" the same thing as "anti-roll bar?" But if so, why are they no longer talking about how these are 'decoupled?' Instead, it reads like the AIRMATIC system is being used.
Last edited by gplank; May 7, 2012 at 06:17 PM.
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From: Lake Oswego, OR
2020 GLE 450; 2023 BMW M2 Coupe
Active Curve System
Has anyone noticed that the description of the Active Curve System has silently changed? Or is it just me?
In the new descriptions I'm finding online, Active Curve no longer decouples anti-roll bars on and off to create stabilization, it instead uses a hydraulic pump from (what I assume) the AIRMATIC system.
While they removed the Active Curve System description entirely from MBUSA's ML web pages weeks ago, the MBUSA AMG ML63 still describes the Active Curve System. But I swear it's now different...it just talks about 'variable front and rear stabilizers" and nothing about anti-roll bars
The old description of the Dynamic Handling Package and how the Active Curve system decouples anti-roll bards for both on and off is still described in this German MB tech center website:
"ACTIVE CURVE SYSTEM boosts driving comfort significantly:When cornering, the stabiliser bars are actively impacted and keep the torsional moment constant. The roll distribution is variable to enable the vehicle to be adapted to almost any situation. The driver has the feeling of gliding on rails, particularly in vehicles with a high centre of gravity. In off-road environments, the system guarantees improved axle roll by decoupling the two stabiliser bars at the front and rear axles."
Car & Driver also wrote about the 'anti-roll' bars in this old review:
"That $5150 option includes the Active Curve System (ACS), which decouples the anti-roll bars both off-road and during straight-ahead freeway slogs."
However, this newly update European site now also describes the Active Curve System in a new way. "The ACTIVE CURVE SYSTEM, also called roll stabilization, reduces the vehicle’s roll angle when cornering or driving off road by using its active suspension stabilizers. This enhances ride comfort for the vehicle occupants and boosts driving dynamics off the road, at medium speed (winding rural roads) and also at high speed (motorway). The ACTIVE CURVE SYSTEM determines the roll forces acting on the vehicle by means of pressure sensors in the front and rear axle rotary actuators and a lateral acceleration sensor. An electronic control unit then sends actuating signals to the valve blocks on the front and rear axle, thus controlling the oil flow in the system produced by the hydraulic pump. The pressure in the chambers and the configuration of the active suspension stabilizers mounted on each axle are then adjusted to the driving situation."
So, the question is: Did MB really change the Active Curve System recently? Is this why they suddenly stopped offering it in the ML-class (except for the AMG ML63)? They said it was a parts shortage. Has this led to a re-design? Or is there something wrong with the anti-roll bar design? Did it not work well enough? Was it too expensive to implement?
Or am I'm reading this all wrong? Is "active suspension stabilizers" the same thing as "anti-roll bar?" But if so, why are they no longer talking about how these are 'decoupled?' Instead, it reads like the AIRMATIC system is being used.
In the new descriptions I'm finding online, Active Curve no longer decouples anti-roll bars on and off to create stabilization, it instead uses a hydraulic pump from (what I assume) the AIRMATIC system.
While they removed the Active Curve System description entirely from MBUSA's ML web pages weeks ago, the MBUSA AMG ML63 still describes the Active Curve System. But I swear it's now different...it just talks about 'variable front and rear stabilizers" and nothing about anti-roll bars
The old description of the Dynamic Handling Package and how the Active Curve system decouples anti-roll bards for both on and off is still described in this German MB tech center website:
"ACTIVE CURVE SYSTEM boosts driving comfort significantly:When cornering, the stabiliser bars are actively impacted and keep the torsional moment constant. The roll distribution is variable to enable the vehicle to be adapted to almost any situation. The driver has the feeling of gliding on rails, particularly in vehicles with a high centre of gravity. In off-road environments, the system guarantees improved axle roll by decoupling the two stabiliser bars at the front and rear axles."
Car & Driver also wrote about the 'anti-roll' bars in this old review:
"That $5150 option includes the Active Curve System (ACS), which decouples the anti-roll bars both off-road and during straight-ahead freeway slogs."
However, this newly update European site now also describes the Active Curve System in a new way. "The ACTIVE CURVE SYSTEM, also called roll stabilization, reduces the vehicle’s roll angle when cornering or driving off road by using its active suspension stabilizers. This enhances ride comfort for the vehicle occupants and boosts driving dynamics off the road, at medium speed (winding rural roads) and also at high speed (motorway). The ACTIVE CURVE SYSTEM determines the roll forces acting on the vehicle by means of pressure sensors in the front and rear axle rotary actuators and a lateral acceleration sensor. An electronic control unit then sends actuating signals to the valve blocks on the front and rear axle, thus controlling the oil flow in the system produced by the hydraulic pump. The pressure in the chambers and the configuration of the active suspension stabilizers mounted on each axle are then adjusted to the driving situation."
So, the question is: Did MB really change the Active Curve System recently? Is this why they suddenly stopped offering it in the ML-class (except for the AMG ML63)? They said it was a parts shortage. Has this led to a re-design? Or is there something wrong with the anti-roll bar design? Did it not work well enough? Was it too expensive to implement?
Or am I'm reading this all wrong? Is "active suspension stabilizers" the same thing as "anti-roll bar?" But if so, why are they no longer talking about how these are 'decoupled?' Instead, it reads like the AIRMATIC system is being used.
The key is that the antiroll bars can go to full soft (decoupled) to full on by means of a variable system pressure, most likely operating on the end links. I would guess it's a dedicated hydraulic pump for this system. I'll let you know when I get mine in a couple months. Might be a reason for extended warranty - sounds complex.
Last edited by GregW / Oregon; May 7, 2012 at 11:02 PM.
Registered User
Joined: Feb 2002
Posts: 97
Likes: 1
From: Ontario, Canada
2010 E550 / 2012 ML 550
Active curve system.....
I am not sure of the technical details, but having the ACS is 110 % worth it ! I have a 2012 ML550 with active curve, and going on / off highway exit ramps etc, it actually corners flatter than my E550 when its in 'sport setting'.....
I drove an ML 350 without active curve, and its like driving two completely different vehicles....
The driving dynamics is far superior with active curve....
Please try and order active curve for your ML........it will be the best thing you ever did
Anyone with an ML63 (which has the ACS standard) will verify that.....
I drove an ML 350 without active curve, and its like driving two completely different vehicles....
The driving dynamics is far superior with active curve....
Please try and order active curve for your ML........it will be the best thing you ever did
Anyone with an ML63 (which has the ACS standard) will verify that.....
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Posts: 6,770
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From: Lake Oswego, OR
2020 GLE 450; 2023 BMW M2 Coupe
Active Curve System technical
Okay, I knew I had this somewhere. Here is more detail on how it works. The hydraulically powered "rotary actuator" at the center of each bar apparently can vary the connection between the two parts from disconnected to fully connected, depending on various parameters. I would like to find out exactly how the machanics work, though.
Last edited by GregW / Oregon; May 9, 2012 at 04:40 PM.
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MBs
http://www.freepatentsonline.com/7866253.pdf
MBWorld Fanatic!
Joined: Jul 2003
Posts: 6,770
Likes: 1,264
From: Lake Oswego, OR
2020 GLE 450; 2023 BMW M2 Coupe
ACS rotary acutator technical details
Looks like the hydraulic rotary actuator is covered by this patent, which also explains a bit how it's supposed to work.
http://www.freepatentsonline.com/7866253.pdf
http://www.freepatentsonline.com/7866253.pdf
Last edited by GregW / Oregon; May 9, 2012 at 10:39 PM.
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Joined: Nov 2005
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From: Quebec-Canada
2013 ML-63 AMG- 2010 C350 4matic
Looks like the hydraulic rotary actuator is covered by this patent, which also explains a bit how it's supposed to work.
http://www.freepatentsonline.com/7866253.pdf
http://www.freepatentsonline.com/7866253.pdf
"The key componentry of the ACTIVE CURVE SYSTEM comprises a belt-driven hydraulic pump and an oil reservoir in the engine compartment, as well as a valve block and active anti-roll bars at both the front and rear axles. In contrast to a passive anti-roll bar, the active variant is split into two in the middle, and the two halves are connected with one another by means of hydraulic rotary actuators. Using the CAN signals relayed to it by pressure sensors and a lateral acceleration sensor, the electronic control unit regulates the hydraulic pressure.
The complex workings of the ACTIVE CURVE SYSTEM:
The hydraulic pump feeds oil to the system from the oil reservoir. The pressure control valves and directional control valves integrated into the valve blocks at the front and rear axles set the desired pressure and twist the active anti-roll bars in the appropriate direction for the driving situation. Inside the hydraulic rotary actuators that are built into the active anti-roll bars there are six oil-filled chambers, three of which are pressurised for each direction of travel, i.e. a left or right-hand bend. The front valve block additionally assumes the task of distributing the oil flow between the two axles, irrespective of load."
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BMW X5d
Speaking of active curve system, or "AIRMATIC", I'm looking into buying a used ML and don't want one without the AIRMATIC system in it. I heard the 4MATIC automatically has it, is that true?
Otherwise, how can you tell the vehicle has the system? (If the advert doesn't specifically state that is)
Thanks
Otherwise, how can you tell the vehicle has the system? (If the advert doesn't specifically state that is)
Thanks
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From: Atlanta, GA USA
2000 MB G500 NMLE, 2015 Audi Q7 3.0 TDI Prestige
Speaking of active curve system, or "AIRMATIC", I'm looking into buying a used ML and don't want one without the AIRMATIC system in it. I heard the 4MATIC automatically has it, is that true?
Otherwise, how can you tell the vehicle has the system? (If the advert doesn't specifically state that is)
Thanks
Otherwise, how can you tell the vehicle has the system? (If the advert doesn't specifically state that is)
Thanks
Get someone to look up the Vehicle Data Card, and it will list it if it's there.
Junior Member
Joined: Oct 2009
Posts: 64
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From: New York City
2014 ML63
possible some one help with this ACR system on my '12 ML 350 BTC
whenever turning left ( has to have some incline ) it will give me a malfunction on the dash . When scanning says " control unit " malfunction.
Junior Member
Joined: Oct 2009
Posts: 64
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From: New York City
2014 ML63
W166 AIRMATIC / ACS/ ADS System HELP !!
Bump ...
replaced both front air shocks with oem parts , new compressor , new level sensors , new sway bar links , new rear block , before the ML350 BTC gave me an error on the dash ( whenever making a left turn on an angle road with speeds above 30 mph )
replaced the rear valve block all fine now , however whenever driving and maneuvering the SUV it's very unstable ( as if wants to go under you / slow response more like delayed responses on body roll / movement)
after several visits in and out the shop
without a car
frustrating/ puzzling moments for everyone
any help ? Ideas ?
Anyknow knows the location of the "roll control " or control unit for the ADS system ?
