Rule changes could trigger stability control boom.
Tony Lewin - Automotive News - Feb. 27, 2007
Electronic Stability Programming recognizes critical driving conditions by analyzing data from sensors, taking control of the braking system, engine electronics and steering and then stabilizing the vehicle.
Suppliers already are profiting on systems that control vehicle stability, but European and U.S. regulatory changes are likely to boost this business even more.
Antilock brakes are standard on many new cars sold in Europe and North America. Traction control also is becoming a popular feature.
But last September, stability control systems suddenly became a hotter seller for some suppliers, including Continental AG and Robert Bosch GmbH. That's because the National Highway Traffic Safety Administration recommended that electronic stability control become mandatory for all light vehicles sold in the United States starting with the 2009 model year.
NHTSA said electronic stability control could prevent two-thirds of all rollover crashes and a third of single-vehicle accidents -- 59 percent for SUVs. NHTSA officials called the technology the greatest lifesaver since the introduction of the seat belt.
Electronic stability control is mostly a software add-on for cars with antilock brakes because it uses the same sensors and actuators. But the technology has been a slow seller in its decade on the market.
In 2005, the latest year for which data are available, only one-fourth of new cars sold in the United States had electronic stability control. In Europe, the rate was 40 percent.
In Germany, the driving force behind stability control development, the adoption rate was 72 percent. German supplier Bosch and Mercedes-Benz pioneered the technology in 1995 with a system Bosch calls ESP.
The pending U.S. government action would create annual U.S. demand for about 16 million electronic stability control systems within two years. European safety advocates already are calling for a parallel European Union requirement.
Market research firm Frost and Sullivan estimates the 2005 European market for stability control systems at about $2.10 billion. It estimates that will expand to $4.78 billion by 2012.
Based on existing systems
Electronic stability control systems are complex, but they are based largely on hardware already present for antilock braking and traction control systems. This family of vehicle control technologies started in the 1970s with ABS.
But electronic stability control goes far beyond braking stability and controlling the spin of a vehicle's wheels. The technology controls lateral stability, preventing vehicles from spinning out of control. It does this by braking individual wheels to keep the vehicle on course.
As more suppliers started making stability control systems, producers started offering enhancements, such as brake controls and modifications that limit understeer on turns.
Four years ago, Volvo, working with parent Ford Motor Co., pioneered another electronic stability control enhancement: roll stability control. It applies electronic stability control-type strategies to prevent rollovers -- which account for an increasing proportion of fatalities, especially in North America.
In 2005, Bosch announced its ESP Premium would increase the speed and accuracy of the system. ESP Premium debuted on the BMW X5 SUV, introduced last December.
"It will give us a considerable contribution to rollover safety in all markets," says Volkmar Denner, Bosch board member in charge of electronics and body systems.
"The main demand will come from the U.S., however."
Like a competing system from TRW Automotive's Premium ESC, ESP Premium intervenes in the vehicle's steering and braking to preserve the car's stability and stay on the driver's intended course.
The next step is to apply engine power to enhance stability.
Suppliers of electronic stability control systems are developing systems that direct carefully controlled engine torque to individual wheels. This so-called torque vectoring would offer still greater control of the vehicle's trajectory.
Suppliers Bosch, ZF Friedrichshafen AG, Getrag, Magna Steyr and Ricardo are among the companies working on such systems. Honda already has one on its 2006 Legend sedan. The Honda system, called Super Handling All Wheel Drive, uses Bosch electronics.
Even before NHTSA's action in the United States, European safety advocates were calling for mandatory use of electronic stability control
For instance, Europe's car-testing organization, Euro NCAP, notes the presence of electronic stability control in calculating its star rating systems. It's the first time Euro NCAP included an active safety feature in its ratings.
Active safety describes systems that help avoid accidents. Passive safety features reduce the consequences of accidents that happen.
Euro NCAP says electronic stability control is perhaps the only active safety system that can prove its benefits with statistics, an essential requirement for inclusion in Euro NCAP scoring.
Researchers: It works
"We have data showing that ESC-equipped cars are under-represented in accidents," says Adrian Hobbs, secretary-general of Euro NCAP and a former head of crashworthiness at the Transport Research Laboratory in England.
Adds Matthew Avery, manager of the Thatcham Research Center's crash laboratory near London: "This is collision avoidance technology. The data is irrefutable."
Avery thinks electronic stability control has the potential to save more than 400 lives annually in the United Kingdom alone.
He estimates an electronic stability control system costs a little less than $100.
Advocates are confident the European Union eventually will either require the system or subsidize the purchase of electronic stability control.
They are working to create a standardized test to establish minimum performance for stability control systems.
How electronic stability control works
Electronic stability control systems depend on two types of sensors.
One kind measures motion of the vehicle: wheel speeds, yaw rates (how quickly the vehicle turns on its vertical axis) and lateral acceleration. Other sensors measure what the driver does: steering angle, position of the throttle and brake pressure.
A basic electronic stability control system compares the vehicle's actual trajectory with what the sensors say the driver intended. If they differ, the system applies the brakes on individual wheels to move the vehicle back onto its intended course.
Newer systems can have other functions, too. Roll stability systems add a gyroscopic sensor to measure body roll. If a vehicle is in danger of overturning, the system applies brakes on individual wheels to stabilize the vehicle. Some systems also intervene in steering.
Third-generation electronic stability control systems, such as Bosch's ESP Premium on the new BMW X5 SUV, have higher-pressure, faster-acting pumps. The system also can sense when the vehicle is in a critical state. At that point, it prepares the airbags to react faster if the vehicle rolls over or crashes into a pole.
Several suppliers are developing torque-vectoring systems. Besides being able to brake individual wheels, these systems also can control yaw by feeding extra torque to individual wheels.