Active Body Control, or ABC, is the

Mercedes-Benz Mercedes-Benz (), commonly referred to as Mercedes and sometimes as Benz, is a German luxury and commercial vehicle automotive brand established in 1926. Mercedes-Benz AG (a Mercedes-Benz Group subsidiary established in 2019) is headquartere ...

brand A brand is a name, term, design, symbol or any other feature that distinguishes one seller's good or service from those of other sellers. Brands are used in business, marketing, and advertising for recognition and, importantly, to create an ...

name used to describe electronically controlled

hydropneumatic suspension Hydropneumatic suspension is a type of motor vehicle suspension system, designed by Paul Magès, invented by Citroën, and fitted to Citroën cars, as well as being used under licence by other car manufacturers, notably Rolls-Royce ( Silver Shado ...

. This suspension combines a high level of ride quality with control of the vehicle body motions, and therefore virtually eliminates

body roll Body roll is the axial rotation of a Vehicle, vehicle’s Vehicle frame, body towards the outside of a turn. Body roll occurs because the Compliant mechanism, compliance in Car suspension, vehicle suspension allows the vehicle body, which sits upo ...

in many driving situations including cornering,

accelerating In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by th ...

, and

braking A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction. Background ...

. Mercedes-Benz has been experimenting with these capabilities for automobile suspension since the

air suspension Air suspension is a type of vehicle suspension powered by an electric or engine-driven air pump or compressor. This compressor pumps the air into a flexible bellows, usually made from textile-reinforced rubber. Unlike hydropneumatic suspension, ...

of the 1963 ''600'' and the hydropneumatic (fluid and air) suspension of the 1974 ''6.9''. ABC was only offered on

rear-wheel drive Rear-wheel drive (RWD) is a form of engine and transmission layout used in motor vehicles, in which the engine drives the rear wheels only. Until the late 20th century, rear-wheel drive was the most common configuration for cars. Most rear-wheel ...

models, as

all-wheel drive An all-wheel drive vehicle (AWD vehicle) is one with a powertrain capable of providing power to all its wheels, whether full-time or on-demand. The most common forms of all-wheel drive are: ;1x1 : All unicycles Reflecting one axle with one w ...

4MATIC models were available only with ''Airmatic'' semi-active

, with the 2019

Mercedes-Benz GLE The Mercedes-Benz GLE, formerly Mercedes-Benz M-Class (designated with the "ML" nomenclature), is a mid-size luxury SUV produced by the German manufacturer Mercedes-Benz since 1997. In terms of size, it is slotted in between the smaller GLC a ...

450 4MATIC being the first AWD to have ABC available. The production version was introduced at the 1999

Geneva Motor Show The Geneva International Motor Show is an annual auto show held in March in the Swiss city of Geneva. The show is hosted at the Palexpo, a convention centre located next to the Geneva Cointrin International Airport. The Salon is organised by th ...

on the new Mercedes-Benz CL-Class C215.

Description

In the ABC system, a computer detects body movement from sensors located throughout the vehicle, and controls the action of the

active suspension An active suspension is a type of automotive suspension on a vehicle. It uses an onboard system to control the vertical movement of the vehicle's wheels relative to the chassis or vehicle body rather than the passive suspension provided by large sp ...

with the use of

hydraulic Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counter ...

servomechanism In control engineering a servomechanism, usually shortened to servo, is an automatic device that uses error-sensing negative feedback to correct the action of a mechanism. On displacement-controlled applications, it usually includes a built-in ...

s. The hydraulic pressure to the servos is supplied by a high pressure radial piston hydraulic pump, operating at 3,000psi. Accumulators regulate the hydraulic pressure, by means of an enclosed nitrogen bubble separated from the hydraulic fluid by a membrane. A total of 13 sensors continually monitor body movement and vehicle level and supply the ABC controller with new data every ten

millisecond A millisecond (from '' milli-'' and second; symbol: ms) is a unit of time in the International System of Units (SI) equal to one thousandth (0.001 or 10−3 or 1/1000) of a second and to 1000 microseconds. A unit of 10 milliseconds may be called ...

s. Four level sensors, one at each wheel measure the ride level of the vehicle, three accelerometers measure the

vertical Vertical is a geometric term of location which may refer to: * Vertical direction, the direction aligned with the direction of the force of gravity, up or down * Vertical (angles), a pair of angles opposite each other, formed by two intersecting s ...

body acceleration, one acceleration sensor measures the longitudinal and one sensor the

transverse Transverse may refer to: *Transverse engine, an engine in which the crankshaft is oriented side-to-side relative to the wheels of the vehicle *Transverse flute, a flute that is held horizontally * Transverse force (or ''Euler force''), the tangen ...

body acceleration. As the ABC controller receives and processes data, it operates four

servos, each mounted on an air and pressurized hydraulic fluid

strut A strut is a structural component commonly found in engineering, aeronautics, architecture and anatomy. Struts generally work by resisting longitudinal compression, but they may also serve in tension. Human anatomy Part of the functionality o ...

, beside each wheel. Almost instantaneously, the servo regulated suspension generates counter forces to

body lean Body roll is the axial rotation of a Vehicle, vehicle’s Vehicle frame, body towards the outside of a turn. Body roll occurs because the Compliant mechanism, compliance in Car suspension, vehicle suspension allows the vehicle body, which sits upo ...

, dive and squat during various driving maneuvers. A suspension strut, consisting of a steel coil spring and a

shock absorber A shock absorber or damper is a mechanical or hydraulic device designed to absorb and damp shock impulses. It does this by converting the kinetic energy of the shock into another form of energy (typically heat) which is then dissipated. Most sh ...

connected in parallel, as well as a hydraulically controlled adjusting cylinder, are located between the vehicle body and wheel. These components adjust the

cylinder A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infin ...

in the direction of the suspension strut, and change the suspension length. This creates a force which acts on the suspension and dampening of the vehicle in the frequency range up to five

hertz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that on ...

. The system also incorporates

height adjustable suspension Height adjustable suspension is a feature of certain automobile suspension systems that allow the motorist to vary the ride height or ground clearance. This can be done for various reasons including giving better ground clearance over rough terrain ...

, which in this case lowers the vehicle up to between the speeds of for better

aerodynamics Aerodynamics, from grc, ἀήρ ''aero'' (air) + grc, δυναμική (dynamics), is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dyn ...

, fuel consumption, and handling. The ABC system also allows

self-levelling suspension Self-levelling refers to an automobile suspension system that maintains a constant ride height of the vehicle above the road, regardless of load. Purpose Many vehicle systems on a conventional vehicle are negatively affected by the change in attit ...

, which raises or lowers the vehicle in response to changing load (i.e. the loading or unloading of passengers or cargo). Each vehicle equipped with ABC has an “ABC Sport” button that allows the driver to adjust the suspension range for different driving style preferences. This feature allows the driver to adjust the suspension to maintain a more level ride in more demanding driving conditions. The reliable function of the ABC system requires a regular hydraulic oil change and filter replacement. The

Mercedes-Benz C112 The Mercedes-Benz C112 was an experimental mid-engine concept car built in 1991 by German automobile manufacturer Mercedes-Benz as a test bed, similar to the later versions of the C111. Despite using the same chassis code, it was not related to ...

of 1991,

Mercedes-Benz Vario Research Car The Mercedes-Benz Vario Research Car was a concept study by then Daimler-Benz unveiled at the 1995 Geneva Motor Show. The goal was to show off control, design, and comfort innovations in passenger cars. Innovations *Interchangeable bodies: seda ...

of 1995 and the

Mercedes-Benz F200 The Mercedes-Benz F 200 "Imagination" coupe was a concept study by then Daimler-Benz unveiled at the 1996 Paris Motor Show. The goal was to show off innovations in control, design, and comfort in passenger cars. The car's exterior design was in pa ...

of 1996 already featured prototype versions of ABC. The first complete and ready-for-production version of ABC was introduced in 1999 on the top-of-the-line

Mercedes-Benz CL-Class (C215) The second generation of the Mercedes-Benz CL-Class is the C215-chassis coupé of 1998–2006. It is based on the 1998–2005 Mercedes-Benz S-Class (W220), though it rides on an shorter wheelbase. Sales in Germany started in August 1999 for th ...

. In 2006, the

Mercedes-Benz CL-Class (C216) The Mercedes-Benz C216 is the last generation for the grand tourer with name Mercedes-Benz CL-Class. It replaced the C215 platform. In 2014 it was replaced by the C217 S-Class Coupe. Initial release (2006–) Like its predecessors, the C216 ...

introduced the second generation ''Active Body Control'' suspension, referred to as ''ABC Plus'' or ''ABC II'' in technical documentation. This updated suspension reduced body roll by 45% compared to the first generation ABC suspension. ABC Plus had an updated hydraulic system design, with shorter hydraulic lines, and the pulsation damper was relocated to be mounted directly on the tandem pump. In 2010 a

crosswind stabilization Crosswind stabilization (CWS) is a relatively new advanced driver-assistance system in cars and trucks that was first featured in a 2009 Mercedes-Benz S-Class. CWS assists drivers in controlling a vehicle during strong wind conditions such as dri ...

function was introduced. In strong gusts of crosswind, and depending on the direction and intensity of the wind having an effect on the vehicle, this system varies the wheel load distribution in such a way that the effects of winds are largely compensated or reduced to a minimum. For this purpose the ABC control unit uses the yaw rate, lateral acceleration, steering angle and road speed sensors of the

Electronic Stability Program Electronic stability control (ESC), also referred to as electronic stability program (ESP) or dynamic stability control (DSC), is a computerized technology that improves a vehicle's stability by detecting and reducing loss of traction ( skiddi ...

ESP®.

Magic Body Control

In 2007, the

Mercedes-Benz F700 The Mercedes-Benz F700 is a concept car produced by Mercedes-Benz in 2007. It was first revealed to the public at the 2007 Frankfurt Motor Show. It was given as a gift to UAE The United Arab Emirates (UAE; ar, اَلْإِمَارَات ...

concept introduced the PRE-SCAN suspension, an early prototype road scanning suspension, using

lidar Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be ...

sensors, based on Active Body Control. In 2013 the

Mercedes-Benz S-Class (W222) The Mercedes-Benz W222 is the sixth generation of the S-Class produced from 2013 to 2020, the successor of the W221 S-Class and the predecessor of the W223 S-Class. The W222 was designed during 2009. The original design proposal of the car wa ...

introduced the series production version of PRE-SCAN, but with a

stereo camera A stereo camera is a type of camera with two or more lenses with a separate image sensor or film frame for each lens. This allows the camera to simulate human binocular vision, and therefore gives it the ability to capture three-dimensional i ...

instead of laser projectors. The system dubbed Magic Body Control is fitted with a road-sensing system (Road Surface Scan) that pre-loads the shocks for the road surface detected. Using a

, the system scans the road surface up to 15 meters ahead of the vehicle at speeds up to , and it adjusts the shock damping at each wheel to account for imperfections in the road. Initially only available on 8-cylinder models and above, Magic Ride Control attempts to isolate the car's body by predicting rather than reacting to broken pavement and speed humps. The ABC has undergone major modifications for the new S-Class: the wheel damping is now continuously adjustable, the spring strut response has been improved and the pump efficiency has been further enhanced. A digital interface connects the control unit and the sensors, while the fast FlexRay bus connects the control unit and the vehicle electronics. Processing power is more than double that of the previous system. In 2014 the new C217 S-Class Coupe introduced an update to Magic Body Control, called Active Curve Tilting. This new system allows the vehicle to lean up to 2.5 degrees into a turn, similar to a

tilting train A tilting train is a train that has a mechanism enabling increased speed on regular rail tracks. As a train (or other vehicle) rounds a curve at speed, objects inside the train experience centrifugal force. This can cause packages to slide abo ...

. The leaning is intended to counter the effect of

centrifugal force In Newtonian mechanics, the centrifugal force is an inertial force (also called a "fictitious" or "pseudo" force) that appears to act on all objects when viewed in a rotating frame of reference. It is directed away from an axis which is paralle ...

on the occupants and is available only on rear-wheel drive models

Vehicles

Vehicles, chronological order: *

* Mercedes-Benz CL-Class C215 *

Mercedes-Benz S-Class (W220) The Mercedes-Benz W220 was a range of flagship sedans which, as the fourth generation Mercedes-Benz S-Class, replaced the W140 S-Class after model year 1998 — with long and short wheelbase versions, performance and luxury options; available f ...

, standard on S600 and S55 AMG, optional on other trims * Mercedes-Benz SL Class R230 *

Mercedes-Benz S-Class (W221) The Mercedes-Benz W221 is a chassis code of S-Class, the successor of the Mercedes-Benz S-Class (W220) and the predecessor of the Mercedes-Benz S-Class (W222). The S-Class are the flagship vehicles of Mercedes-Benz and each generation typicall ...

* Mercedes-Benz SL Class R231 *

: Magic Body Control *

Mercedes-Benz S-Class (C217) The Mercedes-Benz S-Class Coupé and Convertible (C217/A217) are grand tourers manufactured by Mercedes-Benz from 2014 to 2020. The C217 model succeeded the C216 CL-Class and is the last version of the S-Class coupé. It is also the first Mer ...

: Magic Body Control

Timeline of active suspension development

*1955

Citroën DS The Citroën DS () is a Front-mid-engine, front-wheel-drive layout, front mid-engined, front-wheel drive executive car manufactured and marketed by Citroën from 1955 to 1975, in fastback/sedan, wagon/estate, and convertible body configurations ...

had

Paul Magès Paul Ernest Mary Magès (1908–1999) is known for his invention of the first self-leveling automobile suspension, known as hydro-pneumatic suspension. This system replaced conventional steel springs with an adaptive system of hydraulic struts, r ...

- the first car with

and

; leveraging the fact that gas/air absorbs force, while fluid transfers force smoothly *1962

Mercedes-Benz W112 : ''See Mercedes-Benz S-Class for a complete overview of all S-Class models.'' The Mercedes-Benz W112 is a luxury automobile produced by Mercedes-Benz from 1961 to 1967. Marketed as the 300SE, it was available as a coupé, convertible, sedan, ...

platform featured an

on the 300SE model and the 1963

Mercedes-Benz 600 The Mercedes-Benz 600 (W100) is a line of ultra-luxury cars produced by Daimler-Benz from 1963 to 1981. The forerunner of the modern Maybach marque, the ''Grosser Mercedes'' ("Grand Mercedes") succeeded the Type 300d "Adenauer" as the compa ...

model *1965

Rolls-Royce Silver Shadow The Rolls-Royce Silver Shadow is a full-sized luxury car produced by British automaker Rolls-Royce in various forms from 1965 to 1980. It was the first of the marque to use unitary body and chassis construction. The Silver Shadow was produced ...

licensed technology from the

offering self-levelling *1974

Maserati Quattroporte The Maserati Quattroporte () is a four-door full-size luxury sports sedan produced by Italian automobile manufacturer Maserati. The name translated from Italian means "four doors". The car is currently in its sixth generation, with the first ge ...

II used the

and

from the

Citroën SM The Citroën SM is a high-performance coupé produced by the French manufacturer Citroën from 1970 to 1975. The SM placed third in the 1971 European Car of the Year contest, trailing its stablemate Citroën GS, and won the 1972 ''Motor Tre ...

*1975

Mercedes-Benz 450SEL 6.9 The 450 SEL 6.9 is the high-performance version of the W116 S-Class saloon. It was based on the long-wheelbase version of W116 chassis introduced in 1972 and equipped with Mercedes-Benz M100 V8 engine and full hydropneumatic suspension system. T ...

with fully

Hydropneumatic suspension Hydropneumatic suspension is a type of motor vehicle suspension system, designed by Paul Magès, invented by Citroën, and fitted to Citroën cars, as well as being used under licence by other car manufacturers, notably Rolls-Royce ( Silver Shado ...

similar in technology, but not geometry, to Citroën design *1979

Mercedes-Benz W126 The Mercedes-Benz W126 is the company's internal designation for its second generation S-Class, manufactured in sedan/saloon (1979–1991) and coupé (1981–1990) models, succeeding the company's W116 range. Mercedes introduced the 2-door C1 ...

then new S class had even more sophisticated

and

. *1984

Mercedes-Benz W124 The Mercedes-Benz W124 is a range of mid-size cars made by Daimler-Benz from 1984 to 1997. The range included numerous body configurations, and though collectively referred to as the W-124, official internal chassis designations varied by body st ...

selected models of E class had this technology (rear only hydraulic suspension)

and

. *1985

Bose Corporation Bose Corporation () is an American manufacturing company that predominantly sells audio equipment. The company was established by Amar Bose in 1964 and is based in Framingham, Massachusetts. It is best known for its home audio systems and speak ...

founder and CEO Dr.

Amar Bose Amar Gopal Bose (November 2, 1929 – July 12, 2013) was an American entrepreneur and academic. An electrical engineer and sound engineer, he was a professor at the Massachusetts Institute of Technology for over 45 years. He was also the found ...

Designed a suspension that mixed passenger comfort and vehicle control, this system used linear electromagnetic motors, power amplifiers, control algorithms and computation speed. *Early-1980s through early '90s, Lotus Engineering, the consultant branch of

Lotus Cars Lotus Cars Limited is a British automotive company headquartered in Norfolk, England which manufactures sports cars and racing cars noted for their light weight and fine handling characteristics. Lotus was previously involved in Formula One r ...

, experimented with

layouts, combining

Electrohydraulic servo valve An electrohydraulic servo valve (EHSV) is an electrically-operated valve that controls how hydraulic fluid is sent to an actuator.https://www.moog.com/literature/ICD/Valves-Introduction.pdf Servo valves are often used to control powerful hydraulic ...

technology from aerospace, a variety of sensors and both analog and digital controllers. About 100 prototype cars and trucks (and several racing cars) were built for a wide variety of customers, with variants of the high bandwidth Lotus Active system. *1986-Lotus Engineering and Moog Inc. formed joint ventur
Moog-Lotus Systems Inc.
to commercialize the Lotus technology with electro-hydraulic servo valves designed by Moog. The joint venture was later purchased by the TRW Steering and Suspension Division. *1989

Citroën XM The Citroën XM is a front-engine, front-drive, five-passenger, five-door hatchback noted for its hydropneumatic suspension. Manufactured and marketed by Citroën from 1989 to 2000, with a minor facelift in 1994, XM production reached 333,405 ov ...

had a similar electronic control of hydraulic suspension, branded

Hydractive Hydropneumatic suspension is a type of motor vehicle suspension system, designed by Paul Magès, invented by Citroën, and fitted to Citroën cars, as well as being used under licence by other car manufacturers, notably Rolls-Royce ( Silver Sha ...

. *1989

Toyota Celica The is an automobile produced by Toyota from 1970 until 2006. The Celica name derives from the Latin word '' coelica'' meaning 'heavenly' or 'celestial'. In Japan, the Celica was exclusive to the ''Toyota Corolla Store'' dealer chain. Produce ...

with

Toyota Active Control Suspension Toyota Active Control Suspension was (according to Toyota) the world's first fully active suspension. It was a complex hydropneumatic, computer-controlled active suspension system. This did away with conventional springs and anti-roll (stabiliser) ...

*1991

Infiniti Q45 The Infiniti Q45 is a full-size luxury sedan manufactured and marketed by Nissan's Infiniti brand for model years 1989-2006, over three generations. The first generation Q45 (1989–1999) was based on the Nissan President; the second generation ...

was optionally equipped with "Full Active Suspension", a world-first in production automobiles. *1991

Toyota Soarer The is a Personal luxury car, personal luxury Grand tourer, GT coupé produced from 1981 to 2005 by Toyota and sold in Japan. It was available at both Japanese Toyota dealerships called ''Toyota Store'' and ''Toyopet Store'', and it debuted with ...

had a fully active hydraulic suspension system on the 1991 UZZ32 model:

. *1994

Citroën Xantia The Citroën Xantia, pronounced "Zan–ti–a" is a large family car ( D) produced by the French automaker Citroën, and designed by Bertone. Presented to the press in December 1992, the car was produced between 1992 and 2002 in Europe, with a f ...

ACTIVA variant introduced

active anti-roll bar An anti-roll bar (roll bar, anti-sway bar, sway bar, stabilizer bar) is a part of many automobile suspensions that helps reduce the body roll of a vehicle during fast cornering or over road irregularities. It connects opposite (left/right) wheel ...

s as an extension to their Hydractive II suspension. *1999 Mercedes-Benz CL-Class C215 introduces ''Active Body Control''.

References

External links

Mercedes-Benz USAMercedes-Benz International
{{Chassis control systems Mercedes-Benz Automotive suspension technologies Automotive technology tradenames Automotive safety technologies Auto parts Mechanical power control