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The Bosch Chapter

The number of fatal accidents each year in the U.S. has hovered at about 40,000 for a decade. Safety organizations, the government and industry are pushing hard to reduce that number to 30,000. Rollovers account for about 30% of light-vehicle fatal accidents, and several brake suppliers are aggressively applying electronics as they attempt to isolate and prevent lethal rollovers on American roadways.

The number of fatal accidents each year in the U.S. has hovered at about 40,000 for a decade. Safety organizations, the government and industry are pushing hard to reduce that number to 30,000.

Rollovers account for about 30% of light-vehicle fatal accidents, and several brake suppliers are aggressively applying electronics as they attempt to isolate and prevent lethal rollovers on American roadways. If every rollover could be mitigated, the goal to limit fatalities to 30,000 suddenly is within reach, they say.

Safety experts know it is not that easy. Some rollovers, such as those caused when a sliding vehicle “trips” over a curb or obstacle, cannot be prevented with even the most advanced technologies available.

But other types of rollovers are avoidable, and brake suppliers say the technology to do so already resides on about 11% of new vehicles in North America. Electronic stability control (ESC) is an advancement of antilock brakes and prevents a vehicle from skidding out of control by determining (from steering wheel inputs) the driver's intended path and then selectively applying stopping force to certain wheels.

Robert Bosch GmbH, a key player in the ESC market, says relatively modest software enhancements to the existing hardware can enable the supplier's ESC system to prevent many rollovers. The company's Rollover Mitigation (ROM) system already is in production for a few vehicles sold in Europe, including the BMW X3 and X5.

Within two years, Bosch expects to have its ROM system on a production vehicle for the U.S. market, says Kay Stepper, marketing manager-Chassis Systems for Bosch's North American operations.

An announcement from an auto maker is expected “very soon,” Stepper tells Ward's.

Stepper says there is a race among suppliers to produce the first rollover-prevention system for the U.S. Bosch had better hurry: Competitors TRW Automotive, Continental Automotive Systems and Delphi Corp. are hot on the trail. Delphi demonstrated its ESC-based rollover prevention technology last fall at the General Motors Corp. proving grounds in Milford, MI.

ESC installation rates are much higher in Europe (approaching 40% this year) than in the U.S., which is expected to see the installation rate on new vehicles skyrocket to 62% by 2010 (according to Bosch), when GM says it will make the feature standard on all vehicles.

For now, braking suppliers are starry-eyed about the potential for growth in the U.S., where a combination of long commutes and an abundance of SUVs and pickups create fertile ground for rollovers.

The National Highway Traffic Safety Admin. says 75% of rollovers occur in vehicles with high centers of gravity, such as SUVs. An evasive lane change, for instance, can cause an SUV to tip.

Bosch's approach is to prevent oversteer, which can cause rollovers in SUVs. Bosch's ROM system recognizes when a vehicle is experiencing extreme lateral tire force and then brakes the outer front wheel in a turn, counteracting the tendency to oversteer.

The effect is to induce understeer, forcing the driver into a slightly wider corner to prevent the rollover. The new algorithms necessary to enable Bosch's ESC for ROM adds nominal cost, Stepper says.

ROM is one piece of Bosch's electronics portfolio aimed at improving vehicle safety. Bosch recently demonstrated its Combined Active and Passive Safety (CAPS) system, which links sensors and control units for ESC with those of airbags and adaptive cruise control (ACC). The system can detect when an accident is imminent and alert unwitting drivers that evasive action is necessary.

ACC is the key driver enabling such preventive measures. When the radar-based device identifies a critical situation, the Predictive Brake Assist system imperceptibly moves the brake pads close to the discs.

If the driver stops suddenly, maximum braking power is applied, shortening the stopping distance. The new Brake Assist system went into production this year for the Audi A6. Bosch quotes studies saying 60% of rear-end collisions could be avoided if the driver were able to react just half a second earlier.

The CAPS approach also can integrate Bosch's Predictive Collision Warning (PCW), which alerts the driver of critical situations with a slight tug on the brakes. PCW also can activate electrical seatbelt pretensioners to pull occupants into the optimal position. Bosch will begin producing this feature for a vehicle in 2006.

Bosch is not alone in pursuing active safety. Continental Automotive Systems has two OEM customers that plan to integrate elements of its new Active Passive Integration Approach in future vehicles.

Predictive safety systems can help reduce by 35% the number of people killed in accidents, says Rainer Kallenbach, executive vice president-Automotive Electronics Div. for Bosch. He suggests the systems can reduce by 45% the cost to the economy of accident damage.

“CAPS will not only be able to prevent or reduce the severity of frontal collisions,” Kallenbach says, “the driver will also be actively assisted and protected in dangerous situations, which potentially lead to side, rear-end or multiple collisions, or even to the vehicle rolling over.”

CAPS fits with the European Union's eSafety initiative, which aims to reduce by 50% the number of road deaths by 2010 by promoting active safety devices.

Bosch demonstrates the CAPS system in an Audi A8, driven toward a large cardboard box. When the ACC radar detects the object in its immediate path, full brake force of up to 1g is applied (without the driver ever touching the pedal), while seatbelts are pulled taut. The system works well in demonstrations, but drivers may find such an intelligent vehicle unsettling until they are accustomed to feeling the car occasionally taking control.

ACC, available on a number of new vehicles, maintains a safe distance to the vehicle ahead. If the lead vehicle stops suddenly, the ACC-equipped vehicle does so as well, automatically, without driver input.

But most ACC systems will not bring a vehicle to a complete stop. They decelerate to about 20 mph (32 km/h); the driver then must complete the stopping event, then step on the accelerator to resume.

In 2006, Bosch will supply an OEM with ACC-plus, which enables “stop-and-go” functionality. Without ever stepping on the brake or accelerator, the system brings the vehicle to a complete stop, then speeds up to keep pace with the vehicle ahead.

That is not to say drivers can relax behind the wheel. A full panic stop requires about 0.7 g of braking force. The Bosch system applies up to 0.4 g; it is up to the driver to provide the rest.

TRW says it also will produce a “stop-and-go” ACC system in 2006.

Bosch currently supplies ACC as an option for the Audi A8 and BMW 7-Series and 5-Series. The supplier says its research determines consumers order ACC between 5% and 10% of the time when it is offered as an option.

Bosch's Solution for Speeding

Robert Bosch GmbH has a device that may keep lead-foot drivers out of trouble with the law.

At its test track in Boxberg, Germany, Bosch demonstrates its roadsign recognition system on a Mercedes-Benz S-Class. A complementary metal oxide semiconductor (CMOS) camera placed below the rear-view mirror surveys the road ahead and is programmed to identify speed-limit and other traffic signs.

The prototype Mercedes S-Class is set up with a black-and-white video display of the road ahead, with the roadsign highlighted in color. Once identified, the vehicle gives audible notification to the driver: “Speed limit, 50.”

The system works as intended, notifying the driver each time speed limits change. The device could be handy in city traffic, where limits frequently change.

It can be programmed for a customer's preference. For instance, a visual notice can be given to the driver, rather than an audible one. The system can be programmed to notify the driver only if the vehicle is exceeding the speed limit by 5 mph or 10 mph (8 or 16 km/h).

The Bosch system recognizes both round European speed-limit signs (above) and rectangular U.S. signs. Bosch says the CMOS camera has high dynamic range, allowing it to work equally well at night or during the day.
by Tom Murphy

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