Active Body Control
Encyclopedia
Mercedes-Benz
Mercedes-Benz is a German manufacturer of automobiles, buses, coaches, and trucks. Mercedes-Benz is a division of its parent company, Daimler AG...
brand
Brand
The American Marketing Association defines a brand as a "Name, term, design, symbol, or any other feature that identifies one seller's good or service as distinct from those of other sellers."...
name used to describe fully active suspension
Active suspension
Active or adaptive suspension is an automotive technology that controls the vertical movement of the wheels with an onboard system rather than the movement being determined entirely by the road surface...
, that allows control of the vehicle body motions and therefore virtually eliminates body roll
Car handling
Automobile handling and vehicle handling are descriptions of the way wheeled vehicles perform transverse to their direction of motion, particularly during cornering and swerving. It also includes their stability when moving at rest. Handling and braking are the major components of a vehicle's...
in many driving situations including cornering, accelerating, and braking.
In the ABC system, a computer detects body movement from sensors located throughout the vehicle, and controls the action of the active suspension with the use of hydraulic servomechanism
Servomechanism
thumb|right|200px|Industrial servomotorThe grey/green cylinder is the [[Brush |brush-type]] [[DC motor]]. The black section at the bottom contains the [[Epicyclic gearing|planetary]] [[Reduction drive|reduction gear]], and the black object on top of the motor is the optical [[rotary encoder]] for...
s. The hydraulic pressure to the servos is supplied by a high pressure radial piston hydraulic pump. A total of 13 sensors continually monitor body movement and vehicle level and supply the ABC controller with new data every ten millisecond
Millisecond
A millisecond is a thousandth of a second.10 milliseconds are called a centisecond....
s. Four level sensors, one at each wheel measure the ride level of the vehicle, three accelerometers measure the vertical
Vertical direction
In astronomy, geography, geometry and related sciences and contexts, a direction passing by a given point is said to be vertical if it is locally aligned with the gradient of the gravity field, i.e., with the direction of the gravitational force at that point...
body acceleration, one acceleration sensor measures the longitudinal and one sensor the transverse
Transversality
In mathematics, transversality is a notion that describes how spaces can intersect; transversality can be seen as the "opposite" of tangency, and plays a role in general position. It formalizes the idea of a generic intersection in differential topology...
body acceleration. At each hydraulic cylinder, a pressure sensor monitors the hydraulic pressure. As the ABC controller receives and processes data, it operates four hydraulic servos, each mounted in series on a spring strut
Strut
A strut is a structural component designed to resist longitudinal compression. Struts provide outwards-facing support in their lengthwise direction, which can be used to keep two other components separate, performing the opposite function of a tie...
, beside each wheel. Almost instantaneously, the servo regulated suspension generates counter forces to body lean, dive, and squat during various driving maneuvers. A suspension strut, consisting of a steel coil spring and a shock absorber
Shock absorber
A shock absorber is a mechanical device designed to smooth out or damp shock impulse, and dissipate kinetic energy. It is a type of dashpot.-Nomenclature:...
are connected in parallel, as well as a hydraulically controlled adjusting cylinder, are located between the vehicle body and wheel. These components are prone to failure, hazardous when fail, but adjust the cylinder
Cylinder (geometry)
A cylinder is one of the most basic curvilinear geometric shapes, the surface formed by the points at a fixed distance from a given line segment, the axis of the cylinder. The solid enclosed by this surface and by two planes perpendicular to the axis is also called a cylinder...
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
Hertz
The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....
.
The system also incorporates height adjustable suspension
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, a lower ground clearance to improve fuel economy...
, which in this case lowers the vehicle up to 11 mm (0.433070866141732 in) between the speeds of 60–160 km/h (37.3–99.4 mph) for better aerodynamics
Aerodynamics
Aerodynamics is a branch of dynamics concerned with studying the motion of air, particularly when it interacts with a moving object. Aerodynamics is a subfield of fluid dynamics and gas dynamics, with much theory shared between them. Aerodynamics is often used synonymously with gas dynamics, with...
, fuel consumption, and handling.
The ABC system also allows self-levelling suspension
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....
, 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.
It was introduced in 1999 on the top-of-the-line Mercedes-Benz CL-Class
Mercedes-Benz CL-Class
The Mercedes-Benz CL-Class is a luxury coupé automobile produced by the German automaker Mercedes-Benz. The name CL stands for the German Comfort Leicht ....
.
This system is standard on all Mercedes-Benz SL
Mercedes-Benz SL-Class
The Mercedes-Benz SL is a grand tourer manufactured by Mercedes since 1954. The designation SL derives from the German Sport Leicht, or Sport Lightweight — and was first applied to the 300SL 'Gullwing' named also after its gullwing or upward-opening doors.The term SL-Class refers to the...
(except for SL350) and CL
Mercedes-Benz CL-Class
The Mercedes-Benz CL-Class is a luxury coupé automobile produced by the German automaker Mercedes-Benz. The name CL stands for the German Comfort Leicht ....
Class models and on S
Mercedes-Benz S-Class
The Mercedes-Benz S-Class is a series of luxury sedans produced by Mercedes-Benz, a division of Daimler AG. The classification was officially introduced in 1972 with the W116 S-Class, which succeeded previous Mercedes-Benz models dating to the mid-1950s...
Class (only S600, S55 AMG and S65 AMG) models sold in the U.S.
Similar technology
- 1955 Citroën DSCitroën DSThe Citroën DS is an executive car produced by the French manufacturer Citroën between 1955 and 1975. Styled by Italian sculptor and industrial designer Flaminio Bertoni and the French aeronautical engineer André Lefèbvre, the DS was known for its aerodynamic futuristic body design and innovative...
had hydropneumatic suspensionHydropneumatic suspensionHydropneumatic suspension is a type of automotive suspension system, invented by Citroën, and fitted to Citroën cars, as well as being used under licence by other car manufacturers, notably Rolls-Royce, and Peugeot. It was also used on Berliet trucks and is since recently used on Mercedes-Benz...
, which had the height adjustable suspensionHeight adjustable suspensionHeight 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, a lower ground clearance to improve fuel economy...
and self-levelling suspensionSelf-levelling suspensionSelf-levelling refers to an automobile suspension system that maintains a constant ride height of the vehicle above the road, regardless of load....
features of ABC, but controlled purely by hydraulic action, since computerComputerA computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
s in that era were larger than an automobile - 1965 Rolls-Royce Silver ShadowRolls-Royce Silver ShadowThe Rolls-Royce Silver Shadow is a luxury car that was produced in Great Britain in various forms from 1965 to 1980. It was the first Rolls-Royce to use a monocoque chassis, a response to concerns that the company was falling behind in automotive innovation....
had technology licensed from Citroën DSCitroën DSThe Citroën DS is an executive car produced by the French manufacturer Citroën between 1955 and 1975. Styled by Italian sculptor and industrial designer Flaminio Bertoni and the French aeronautical engineer André Lefèbvre, the DS was known for its aerodynamic futuristic body design and innovative...
, height adjustable suspensionHeight adjustable suspensionHeight 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, a lower ground clearance to improve fuel economy...
and self-levelling suspensionSelf-levelling suspensionSelf-levelling refers to an automobile suspension system that maintains a constant ride height of the vehicle above the road, regardless of load....
features of ABC - 1975 Mercedes-Benz 450SEL 6.9Mercedes-Benz 450SEL 6.9The Mercedes-Benz 450SEL 6.9 is a high-performance version of the S-Class luxury saloon. It was built on its own assembly line by Daimler-Benz in Stuttgart, Germany and based on the long-wheelbase version of the W116 chassis introduced in 1972...
flagship and the very sleek Rolls-Royce Camargue, had the height adjustable suspensionHeight adjustable suspensionHeight 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, a lower ground clearance to improve fuel economy...
and self-levelling suspensionSelf-levelling suspensionSelf-levelling refers to an automobile suspension system that maintains a constant ride height of the vehicle above the road, regardless of load....
features of ABC again from the Citroën CXCitroën CXThe Citroën CX is an automobile produced by the French automaker Citroën from 1974 to 1991. Citroën sold nearly 1.2 million CXs during its 16 years of production. The CX was voted European Car of the Year in 1975.... - 1979 Mercedes-Benz W126Mercedes-Benz W126The Mercedes-Benz W126 is a series of flagship vehicles manufactured by German automotive marque Mercedes-Benz. Premiering in September 1979 as the successor to the earlier W116 line, the W126 was the second generation of the Mercedes-Benz flagship to officially bear the S-Class name referring to...
then new S class had even more sophisticated height adjustable suspensionHeight adjustable suspensionHeight 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, a lower ground clearance to improve fuel economy...
and self-levelling suspensionSelf-levelling suspensionSelf-levelling refers to an automobile suspension system that maintains a constant ride height of the vehicle above the road, regardless of load....
features of ABC - 1984 Mercedes-Benz W124Mercedes-Benz W124W124 is the Mercedes-Benz internal chassis-designation for the 1985 to 1995 version of the Mercedes-Benz E-Class. The W124 models replaced the W123 models after 1985 and were superseded by the W210 E-Class after 1995.-History:...
selected models of E class had this technology (rear only hydraulic suspension) height adjustable suspensionHeight adjustable suspensionHeight 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, a lower ground clearance to improve fuel economy...
and self-levelling suspensionSelf-levelling suspensionSelf-levelling refers to an automobile suspension system that maintains a constant ride height of the vehicle above the road, regardless of load....
features of ABC - Mid-1980s, Lotus CarsLotus CarsLotus Cars is a British manufacturer of sports and racing cars based at the former site of RAF Hethel, a World War II airfield in Norfolk. The company designs and builds race and production automobiles of light weight and fine handling characteristics...
experimented with active suspensionActive suspensionActive or adaptive suspension is an automotive technology that controls the vertical movement of the wheels with an onboard system rather than the movement being determined entirely by the road surface...
layouts, combining hydraulic and electronicElectronicsElectronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
components. - 1989 Citroën XMCitroën XMThe Citroën XM is an executive car that was produced by the French automaker Citroën between 1989 and 2000. Citroën sold 333,775 XMs during the model's 11 years of production...
had a similar electronic control of hydraulic suspension, branded Hydractive. - 1991 Toyota SoarerToyota SoarerThe Soarer made its first appearance at the 1980 Osaka International Motor Show with the name "EX-8", and the Z10 series Toyota Soarer was produced from February 1981 to December 1985, with 2.0L, 2.8L or 3.0L DOHC I-6 variants. The first generation Soarer debuted with a rear-wheel drive...
had a fully active hydraulic suspension system on the 1991 UZZ32 model. - 1994 Citroën XantiaCitroën XantiaThe Citroën Xantia, pronounced 'Zan-tia' is a large family car produced by the French automaker Citroën. First seen at the end of 1992, the car was produced between 1993 and 2001, with a facelift in 1998. Citroën sold over 1.2 million Xantias during its 8 years of production...
Activa variant introduced a fully active suspensionActive suspensionActive or adaptive suspension is an automotive technology that controls the vertical movement of the wheels with an onboard system rather than the movement being determined entirely by the road surface...
known as Hydractive 2