Electronic Stability Control

Electronic Stability Control (ESC) is the generic term for systems designed to improve a vehicle's handling, particularly at the limits where the driver might lose control of the vehicle.

Robert Bosch GmbH and Mercedes Benz co-developed the first ESC system called Elektronisches Stabilitätsprogramm (ESP®) that was used by Mercedes-Benz in their flagship S-Class. Mercedes Benz licensed this for use to other car manufacturers at no cost, including BMW with their 7 Series in 1995. ESP first came to general notice when the original Mercedes-Benz A-Class (without ESC) failed the moose test (sudden swerving to avoid an obstacle); since Mercedes-Benz has built their reputation on safety, they did not want to be seen to be marketing unsafe vehicles, so at great expense every A-Class was retrofitted with ESC. Mercedes-Benz also became the first manufacturer to make ESC standard across its model range in 1999, with BMW following suit in 2000.

ESP was introduced to the mass market by Mercedes-Benz/Bosch, Continental Automotive Systems, Delphi and TRW, usually under the broader name of Electronic Stability Control, which is the more common term recognized by the Society of Automotive Engineers, although individual car manufacturers use a range of different marketing names (see below).

Operation

ESC compares the driver's intended direction in steering and braking inputs, to the vehicle's response, via lateral acceleration, rotation (yaw) and individual wheel speeds. ESC then brakes individual front or rear wheels and/or reduces excess engine power as needed to help correct understeer (plowing) or oversteer (fishtailing). ESC also integrates all-speed traction control, which senses drive-wheel slip under acceleration and individually brakes the slipping wheel or wheels, and/or reduces excess engine power, until control is regained. ESC cannot override a car's physical limits. If a driver pushes the possibilities of the car's chassis and ESC too far, ESC cannot prevent a crash. It is a tool to help the driver maintain control.

ESC combines anti-lock brakes, traction control and yaw control (yaw is rotation around the vertical axis).

Effectiveness

Numerous international studies have confirmed the effectiveness of ESC in helping the driver maintain control of the car, help save lives and reduce the severity of crashes. In the fall of 2004 in the U.S., the National Highway and Traffic Safety Administration confirmed the international studies, releasing results of a field study in the U.S. of ESC effectiveness. NHTSA concluded that ESC reduces crashes by 35%. Additionally, sport utility vehicles with stability control are involved in 67 percent fewer accidents than SUVs without the system. The Insurance Institute for Highway Safety (IIHS) later issued its own study that concluded the widespread application of ESC could save 7,000 lives a year. In June 2006, the IIHS updated the results of its 2004 study by stating that up to 10,000 fatal crashes could be avoided annually if all vehicles were equipped with ESC.[1] Now being used by other manufacturers, stability control systems reduce the likelihood of all fatal accidents by 43 percent and fatal single-vehicle crashes by 56 percent, according to another accident study by the Insurance Institute for Highway Safety (IIHS). That makes ESC the greatest safety equipment development since seat belts and air bags, according to some experts. The European New Car Assessment Program (EuroNCAP) "strongly recommends" that people buy cars fitted with stability control.[2] On November 21, 2006 the IIHS announced that 13 of the 2007 vehicles had earned its TOP SAFETY PICK rating---a major new requirement for this top rating is that the vehicle must be equipped with ESC.[3]

Cost

According to National Highway Traffic Safety Administration research, Vehicle costs are estimated to be US$368 (in 2005) for anti-lock brakes (ABS) and an additional US$111 for electronic stability control for a total system cost of US$479 per vehicle.

The main additional components of the ESC system in comparison to an ABS system include Yaw Rate/Lateral Acceleration Sensors, a Steering Wheel Sensor, and an upgraded Integrated Control Unit.

Criticism

Some people contend (backed up by the theory of risk compensation) that the perception of safety conferred by the ESC will encourage more dangerous driving. The Partnership for Safe Driving is among those concerned that ESC is just the latest example of a long and ultimately unsuccessful campaign, in the U.S. and abroad, to make cars that are capable of compensating for dangerous driving behavior.[4] The Partnership believes that if no corresponding effort is made to deter speeding, aggressive, distracted and drowsy driving, this technology will not live up to its promise and may, in fact, encourage even more dangerous driving behavior. This theory has been mocked since most road users do not understand these systems and hence just drive as they normally would. The theory has also been dismissed by many due to the fact that statistics from manufacturer's such as ESC pioneers, Mercedes Benz, clearly show the decrease in road accidents after the introduction of the technology.[5]

Some driving enthusiasts object to some of the implementations of ESC. They contend that by making it impossible to explore the dynamic behavior of their cars, overzealous ESC systems spoil much of the fun of driving. Consequently, some manufacturers allow drivers to disable ESC systems, and/or use ESC systems that allow greater levels of under or oversteer before it intervenes. Some even provide a setting so the user can choose whether the system will intervene earlier or later stage. Enthusiasts have also begun to modify ESC systems to suit their preferred driving styles.[6]

It has also been argued that ESC is being used as a "catch all" for poorly designed cars, whereby the basic mechanical handling of a car is unstable and ESC is used to compensate for the problem. However, except in the case of low-end economy cars, and the Mercedes A class, this argument is largely without merit, as high-end performance and/or safety oriented brands like BMW, Ferrari, Mercedes, and Volvo were among the first to adopt ESC.

Another point of critique is that in the case of very dangerous drivers, the car will be able to be pushed further (and faster) before the limits of the vehicle and ESC are reached, meaning that should the vehicle become "out of control" this will happen at higher speeds, leading to more severe crashes. Realistically this scenario is not possible under the ESC program because ESC only controls power delivery and braking and does not increase the physical traction limit of the vehicle. Therefore the vehicle cannot be pushed faster through a corner than is otherwise capable by a skilled driver also approaching the traction limit. The implementation of the ESC program will only control a number of variables including braking, throttle opening and/or injector pulse or ignition timing to reduce power to the road thereby preventing a driver from approaching and surpassing the physical traction limits of the vehicle.

In the event that the vehicle is out of alignment, has dissimilar sized left/right tires fitted, or has a tire with low enough air pressure to affect the steering wheel angle, the yaw rate sensor would conflict with the steering wheel sensor. If this were the case, the vehicle's Powertrain Control Module may interpret the driver's actions as trying to turn the vehicle, rather than compensation for a mechanical problem. However, ECU programmers are familiar with this type of issue, and use cross-correlation between sensors to identify problems.

Overall, ESC systems have resulted in a marked drop in accident rates, overriding most arguments against its implementation.[7]

Perhaps the harshest criticism of ESC systems has been the reluctance by some manufacturers to fit it as standard across all of their models. Specifically, some manufacturers have restricted its fitment to higher specification model variants as a means of encouraging buyers to purchase them, at greater cost. Given the effectiveness of ESC in reducing crashes and saving lives, some safety advocates have accused manufacturers who have offered ESC on their models in this way of cynical marketing.

Design and selection of components

The ESC-system uses several sensors in order to determine the state the driver wants the vehicle to be in (driver demand). Other sensors indicate the actual state of the vehicle (vehicle response). The control-algorithm compares both states and decides, when necessary, to adjust the dynamic state of the vehicle.

The sensors used for ESC have to send data at all time in order to detect possible defects as soon as possible. They have to be resistant to possible forms of interference (rain, holes in the road, etc.). Most important sensors are :
  • Steering wheel sensor : determines the angle the driver wanted to take. This kind of sensor is often based on .
  • Lateral acceleration sensor : often based on the . Measures the lateral acceleration of the vehicle.
  • : measures the (rotation) of the car. The achieved data of the yaw sensor can be compared with the data from the steering wheel sensor in order to take a regulating action.
  • : measures the wheel speed.
ESC uses an hydraulic modulator to assure that each wheel receives the correct brake force. A similar modulator is used in . ABS needs to reduce pressure during braking, only. ESP additionally needs to increase pressure in certain situations.

The heart of the ESC-system is the . The diverse control techniques are embedded in it. Often, the same is used for diverse systems at the same time (, , climate control, etc.). The input signals are sent through the input-circuit to the digital controller. The wanted vehicle state is determined based on the steering wheel angle, its gradient and the wheel speed. Simultaneously, the yaw sensor measures the actual state. The controller computes the needed brake or acceleration force for each wheel and directs via the driver circuits the valves of the hydraulic modulator. Via a the is connected with other systems (, etc.) in order to avoid giving contradictory commands.

Product names

Vehicle manufacturers use electronic stability control systems under different marketing names:
  • Acura: Vehicle Stability Assist (VSA)
  • Alfa Romeo: Vehicle Dynamic Control (VDC)
  • Audi: ESP - Electronic Stabilization Program
  • Buick: StabiliTrak
  • BMW: Dynamic Stability Control (DSC), including Dynamic Traction Control
  • Cadillac: All-Speed Traction Control & StabiliTrak
  • Chevrolet: StabiliTrak; Active Handling (Corvette only)
  • Chrysler: Electronic Stability Program (ESP)
  • Citroën: Electronic Stability Program (ESP)
  • Dodge: Electronic Stability Program (ESP)
  • DaimlerChrysler: Electronic Stability Program (ESP)
  • Fiat: Electronic Stability Program (ESP) and Vehicle Dynamic Control (VDC)
  • Ferrari: Controllo Stabilità (CST)
  • Ford: AdvanceTrac with Roll Stability Control (RSC) and Interactive Vehicle Dynamics (IVD) and Electronic Stability Program (ESP); Dynamic Stability Control (DSC) (Australia only)
  • General Motors: StabiliTrak
  • Hyundai: Vehicle Dynamic Control (VDC) and Electronic Stability Program (ESP)
  • Honda: Electronic Stability Control (ESC) and Vehicle Stability Assist (VSA) and Electronic Stability Program (ESP)
  • Holden: Electronic Stability Program (ESP)
  • Hyundai: Electronic Stability Program (ESP) and Vehicle Stability Assist (VSA)
  • Infiniti: Vehicle Dynamic Control (VDC)
  • Jaguar: Dynamic Stability Control (DSC)
  • Jeep: Electronic Stability Program (ESP)
  • Kia: Electronic Stability Program (ESP)
  • Land Rover: Dynamic Stability Control (DSC)
  • Lexus: Vehicle Dynamics Integrated Management (VDIM) with Vehicle Stability Control (VSC) and Traction Control (TRAC) systems
  • Lincoln: AdvanceTrac
  • Maserati: Maserati Stability Program (MSP)
  • Mazda: Dynamic Stability Control (DSC)
  • Mercedes-Benz (inventors): Electronic Stability Program (ESP)
  • Mercury: AdvanceTrac
  • MINI: Dynamic Stability Control
  • Mitsubishi: Active Skid and Traction Control MULTIMODE
  • Nissan: Vehicle Dynamic Control (VDC)
  • Oldsmobile: Precision Control System (PCS)
  • Opel: Electronic Stability Program (ESP)
  • Peugeot: Electronic Stability Program (ESP)
  • Pontiac: StabiliTrak
  • Porsche: Porsche Stability Management (PSM)
  • Renault: Electronic Stability Program (ESP)
  • Rover: Dynamic Stability Control (DSC)
  • Saab: Electronic Stability Program
  • Saturn: StabiliTrak
  • SEAT: Electronic Stability Program (ESP)
  • Škoda: Electronic Stability Program (ESP)
  • Smart: Electronic Stability Program (ESP)
  • Subaru: Vehicle Dynamics Control Systems (VDCS)
  • Suzuki: Electronic Stability Program (ESP)
  • Toyota: Vehicle Dynamics Integrated Management (VDIM) with Vehicle Stability Control (VSC)
  • Vauxhall: Electronic Stability Program (ESP)
  • Volvo: Dynamic Stability and Traction Control (DSTC)
  • Volkswagen: Electronic Stability Program (ESP)

System Manufacturers

ESC system manufacturers include:

Future

Electronic Stability Control forms the foundation for new advances on vehicle equipment that will save additional lives and give the driver still more control over the vehicle. The computing power of ESC facilitates the networking of active and passive safety systems on the car, creating the opportunity to address still more causes of crashes.

The market for this system is growing at a very robust rate, especially in European countries such as Sweden and Germany. Despite criticism, it is expected that the ESC system will be installed in most vehicles post 2015 in most countries in Europe and also in Japan.

In the US, the NHTSA has recently mandated that ESC be included on every new vehicle by the model year 2012 (September, 2011).[8] The auto industry has widely supported the mandate. [9]

See also

References and External links



[10]
Car handling and vehicle handling is a description of the way wheeled vehicles perform transverse to their direction of motion, particularly during cornering and swerving. It also includes their stability when moving in a straight line.
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Robert Bosch GmbH

GmbH
Founded 1886
Headquarters Gerlingen, Germany

Key people Robert Bosch, founder
Industry Automotive, Small appliance
Products Automotive parts, Power tools
Revenue $43,7 Billions (2006)
Net income $2,17 Billions (2006)
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Please discuss this issue on the talk page and help summarize or split the content into subarticles of an article series.

For other uses of the name Mercedes, see Mercedes.

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Mercedes-Benz S-Class is a series of large luxury flagship sedans produced by Mercedes-Benz, now a division of Daimler AG. The S-Class, a product of nine lines of Mercedes-Benz models dating since the mid-1950s, is the world's best-selling luxury flagship sedan.
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Bayerische Motoren Werke AG

Aktiengesellschaft
Founded 1916
Headquarters Munich, Germany

Key people Dr. Norbert Reithofer, Chairman and CEO
Industry Automotive
Products Automobiles
Motorcycles
Revenue €49 billion (2006)
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BMW 7 Series is a line of full-size luxury vehicles produced by the German automaker BMW. It replaced the "New Six" models in 1977. It is BMW's flagship car and is only available as a sedan.
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The Mercedes-Benz A-Class (popularly known in the U.S. as the Baby Benz) is a small family car produced by the German automaker Mercedes-Benz. The first generation (W168) was introduced in 1997 and a redesign (W169) appeared in 2004.
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The Moose test, also known as the Elk test, Älgtest in Swedish, has been used in Sweden for decades to test how a certain vehicle, usually an automobile, acts when avoiding a sudden danger, such as a moose.

The test is made on dry pavement.
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Continental Automotive Systems (CAS), founded in 1906 by Alfred Teves, a division of Continental AG, is a leading brake and electronics supplier to the automotive industry, delivering systems, components, electronics, lithium-ion batteries and engineering services for vehicle
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Delphi Corp.

Public Pink Sheets: DPHIQ
Founded 1997 in Troy, Michigan, USA
Headquarters Troy, Michigan, USA

Key people Rodney O'Neal, CEO, COO
Robert S. Miller, Chairman
Robert J.
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TRW Automotive Holdings NYSE:  TRW is a supplier of automotive parts to manufacturers and aftermarket dealers. [1] . It was created out of a sell-off of parts of the former TRW corporation.
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SAE International (SAE) is a professional organization for mobility engineering professionals in aerospace, automotive and the commercial vehicle industries.

The Society is a standards development organization for the engineering of powered vehicles of all kinds, including
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Steering is the term applied to the collection of components, linkages, etc. which will allow for a vessel (ship, boat) or vehicle (car) to follow the desired course. An exception is the case of rail transport by which rail tracks combined together with railroad switches provide
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acceleration is defined as the rate of change of velocity, or, equivalently, as the second derivative of position. It is thus a vector quantity with dimension length/time². In SI units, acceleration is measured in metres/second² (m·s-²).
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An engine is something that produces an output effect from a given input. The origin of engineering however, came from the design, building and working of (military "engines") because before such devices came to be employed in battles there were very few mechanical devices used.
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Understeer is a term for a car handling condition during cornering in which the circular path of the vehicle's motion is of a markedly greater diameter than the circle indicated by the direction its wheels are pointed.
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Oversteer is a phenomenon that can occur in an automobile which is attempting to turn. The car is said to oversteer when the rear wheels do not track behind the front wheels but instead slide out toward the outside of the turn. Oversteer can throw the car into a spin.
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A traction control system (TCS), on current production vehicles, are typically (but not necessarily) electro-hydraulic systems designed to prevent loss of traction (and therefore the control of the vehicle) when excessive throttle or steering is applied by the driver.
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chassis (plural: "chassis") (IPA: /ˈʃæːsiː, ˈtʃæːsiː/) consists of a framework that supports an inanimate object, analogous to an animal's skeleton, for example in a motor vehicle or a
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An anti-lock braking system (ABS) (translated from German, Antiblockiersystem) is a system on motor vehicles which prevents the wheels from locking while braking. The purpose of this is to allow the driver to maintain steering control under heavy braking and, in some
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The National Highway Traffic Safety Administration (NHTSA, often pronounced "nit-suh") is an agency of the Executive Branch of the U.S. Government, part of the Department of Transportation.
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The Insurance Institute for Highway Safety is a U.S. non-profit organization funded by auto insurers. It works to reduce the number of motor vehicle crashes, and the rate of injuries and amount of property damage in the crashes that still occur.
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seat belt, sometimes called a safety belt, is a safety harness designed to secure the occupant of a vehicle against harmful movement that may result from a collision or a sudden stop.
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November 21 is the 1st day of the year (2nd in leap years) in the Gregorian calendar. There are 0 days remaining.

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The National Highway Traffic Safety Administration (NHTSA, often pronounced "nit-suh") is an agency of the Executive Branch of the U.S. Government, part of the Department of Transportation.
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United States dollar
dólar estadounidense (Spanish)
dólar amerikanu (Tetum)
dólar americano

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ABS is a three-letter acronym that may refer to:
  • Able Seaman (rank) or Able Seaman (occupation)
  • Absolutive case
  • Abu Simbel Airport (IATA airport code: ABS), in Abu Simbel, Egypt
  • Acrylonitrile butadiene styrene, a plastic

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An anti-lock braking system (ABS) (translated from German, Antiblockiersystem) is a system on motor vehicles which prevents the wheels from locking while braking. The purpose of this is to allow the driver to maintain steering control under heavy braking and, in some
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The of this article or section may be compromised by "weasel words".
You can help Wikipedia by removing weasel words. In ethology, risk compensation is an effect whereby individual animals may tend to adjust their behaviour in response to perceived changes in risk.
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A wheel alignment is part of standard automobile maintenance that consists of adjusting the angles of the wheels so that they are set to the car maker's specification. The purpose of these adjustments is maximum tire life and vehicle-travel that is straight and true when driving
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