Electronic Stability Control
From WOI Encyclopedia Italia
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 were the first to deploy an ESC system, called Elektronisches Stabilitätsprogramm (ESP®) that was used by Mercedes-Benz in their flagship S-Class and, to a lesser extent, in the 7 Series by BMW in 1995. It came to prominence immediately, when the original Mercedes-Benz A-Class (without ESC) failed the moose test; since Mercedes-Benz could not afford to be perceived as marketing unsafe vehicles, every A-Class was retrofitted with ESC at great expense.
ESC was then introduced to the mass market by 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 motor manufacturers use a range of different marketing names (see below).
Contents |
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 spin around a 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%. The Insurance Institute for Highway Safety (IIHS) later issued their 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 their 2004 study by stating that up to 10,000 fatal crashes could be avoided annually if all vehicles were equipped with ESC.[1] That makes ESC the greatest safety equipment development since seat belts, 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 their TOP SAFETY PICK rating--- a major new requirement for this top rating is that the vehicle must be equipped with ESC[3] However, 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, as seems to be the case with seat belts. 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 behaviour is the Partnership for Safe Driving www.crashprevention.org. 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 behaviour.
Criticism
Some driving enthusiasts, most publicly motoring journalists from enthusiast magazines, object to some of the implementations of ESC. They contend that by making it impossible to explore the dynamic behaviour 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 ESP 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 [4].
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, like in the first version of Mercedes-Benz A-Class that failed the moose test and to fix this, every A-Class was retrofitted with 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.
In the event that the vehicle is out of alignment or has a tire with low enough air pressure to affect the steering wheel's angle, the yaw rate sensor would conflict with the steering wheel sensor. If this were the case, the vehicle's Powertrain Controle 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.Template:Fact
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 (except Corvette - Active Handling)
- 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 and Interactive Vehicle Dynamics (IVD); Dynamic Stability Control (DSC) (Australia only); Electronic Stability Program (ESP)
- General Motors: StabiliTrak
- Hyundai: Vehicle Dynamic Control (VDC)
- 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)
- 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: AdvanceTrak
- Maserati: Maserati Stability Program (MSP)
- Mazda: Dynamic Stability Control
- Mercedes-Benz: Electronic Stability Program (ESP)
- Mercury: AdvanceTrak
- 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) now TC from the 2007 GT3 and onwards
- 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)
- 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)
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).[http://www.consumeraffairs.com/news04/2006/09/nhtsa_stability.html 3
See also
- Anti-lock braking system (ABS), an earlier and less complex braking system.
- Traction control
- Moose test
- Hill Start Assist
- Car handling
- Center of mass
- Drifting
- Electronic Stability Control
- Fishtailing
- Inboard brake
- Oversteer
- Steering
- Suspension (vehicle)
- Tire
- Understeer
- Unsprung weight
- Vehicle dynamics
- Weight transfer
External links
- Bosch ESP-erience Site
- Australian Vehicle Safety Information lists vehicles sold in Australia fitted with ESP
- Continental Automotive Systems
- SafelyThere - Continental Automotive Systems
- Vehicle Safety Equipment "Drive Safer America"
- Euro NCAP recommendation of stability control
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