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| Not Your Father’s Safety Systems |
January 19, 2004 |
By Paul Williams
It’s a sure recipe for disaster: driving in a tight circle at 50km/h on a wet asphalt surface in a rear-wheel-drive car, and suddenly flooring the accelerator. But that’s just what Pierre Savoy, my instructor at BMW Driver Training in Downsview, Ont., was telling me to do.
So I did.
Almost instantly, the back end of the car skidded sideways and the vehicle violently whipped around on its axis. If you tried this in traffic, perhaps to avoid a road hazard, you’d end up in the ditch, or worse.
Then we switched on the car’s Dynamic Stability Control (DSC) and I performed the same manoeuvre. The difference was remarkable. You couldn’t knock that car out of control if you tried.
The car seemed to know exactly what it was doing.
DSC is BMW’s proprietary name for electronic stability control (ESC), one part of a suite of computer-managed systems designed to help drivers avoid accidents. Such systems are becoming increasingly prevalent in new cars, although consumers may not yet be aware of their effectiveness.
Several recent studies claim that ESC can prevent crashes and help save thousands of lives. One study by Toyota in Japan showed a 35 per cent reduction of single-vehicle crashes for vehicles equipped with ESC.
Is ESC the auto industry’s best-kept secret? Not deliberately, although these systems are still fairly new and typically found on high-end brands like BMW, Porsche (Porsche Stability Management), Saab (Electronic Stability Program), Audi (Electronic Stabilization Program), Cadillac (Stabilitrac), Lexus (Vehicle Stability Control) and Infiniti (Vehicle Dynamic Control). But that could be changing. Similar systems are trickling down to more mainstream vehicles like the new Ford Freestar van with AdvanceTrac, Ford’s version of ESC.
“We’re putting AdvanceTrac into family vehicles like the Freestar and Explorer at a price that’s hard to refuse ($800),” said Bill Rowe of Ford Canada. “It’s the same system found in the Lincoln Navigator and LS sedan. Now we’re trying to get the word out.”
Cort Neilsen, technical specialist at BMW Canada, said technologies developed independently over the last decade are converging in single vehicles. Building upon anti-lock brake systems (ABS), additional features like electronic brake force distribution, cornering control, dynamic brake control, automatic stability control and computerized engine management can be combined to almost instantly register, analyze and react to forces that may upset a vehicle. ESC is one of those outcomes.
But is it really that effective? Let’s put it this way: this is not your father’s traction control.
That’s because ESC detects imminent instability. Sensors monitor any tendency of the vehicle to rotate on its axis (yaw), causing the system to initiate a reduction of drive torque and send rapid brake pulses to specific wheels. In normal driving, this happens continuously, takes milliseconds and is transparent to the driver.
In an emergency, however, you’ll certainly feel ESC’s more aggressive attempts to maintain control as it employs countermeasures to regain traction and handling. Some systems, like the one used in Volvo’s XC90, use an additional gyroscopic sensor to actually pre-empt rollovers. Volvo’s Roll Stability Control (RSC) monitors the XC90’s angle. If it senses that the vehicle is approaching a critical roll angle, it will activate ESC.
Typically, ESC is a silent partner, although when required it may temporarily exert control to get you out of a dangerous situation.
KEEPING YOUR DISTANCE
On the highway in a Lexus LS 430 recently, I had occasion to try another new technology: the so-called “intelligent” cruise control.
Basically, the system permits you to set a minimum-allowed distance between your car and the one in front of you. Then you set your speed. When your car approaches a slower vehicle in the same lane, it matches that car’s speed and maintains your pre-set distance. If you want to get back up to speed, simply change lanes.
With a clear path ahead, the car will automatically resume its pace.
The car uses laser radar to detect vehicles in your path. This feeds directly to the engine management system and anti-lock brakes, which then react accordingly. Should you find yourself heading for a car that’s rapidly slowing down, the system will hit the brakes in an attempt to avoid a collision.
Of course, intelligent cruise doesn’t steer and it’s not infallible. If you’re entering a long curve, for instance, the slower car in front may disappear from view as the laser radar points straight into a farmer’s field. Your car’s not driving itself by any means.
AUTOPILOT? ALMOST
Active steering is another new technology finding its way into cars, and, to an extent, it does steer for you. In the new BMW 645Ci luxury coupe and 5-Series sedans, sensors detect lateral forces on the car, such as a sudden gust of wind. Active Steering is networked to the ESC system and employs an electric motor located between the steering wheel and the rack and pinion assembly to compensate for any unintentional sideways motion of the car. In this example, the driver doesn’t have to turn the steering wheel whatsoever. On the road, it’s the smoothest, straightest-tracking drive you’ve ever experienced.
An additional characteristic of this system is the steering ratio varies depending on your speed. Making a U-turn at 10km/h, for instance, requires less than two turns of the steering wheel.
As the vehicle’s speed increases, the steering becomes less direct, requiring more turns of the steering wheel to turn the tires.
In general, these three technologies — electronic stability control, laser cruise control and active steering — increase the vehicle’s connectedness to the outside world by allowing it to respond to exterior conditions.
And there are many non-safety functions manufacturers are throwing in. The OnStar communications system from General Motors monitors a vehicle’s location and condition, and notifies authorities if it appears to have been stolen or involved in a crash.
Similarly, DVD-based GPS systems provide comprehensive road maps, calculate routes and identify local points of interest like parks, theatres and hospitals.
But that’s child’s play when it comes to potential applications for in-car communications systems. BMW is working on technology to facilitate “autonomous, self-organizing communications networks” between vehicles. In this scenario, your car would act as the transmitter, receiver and intermediary for information that would warn drivers of black ice ahead, a car crash around the next corner, or an upcoming traffic jam.
Effectively, the cars around you would be forming ad hoc networks to exchange information about prevailing road conditions as you drive. In other words, they’d be talking to each other.
Toyota is taking this to its logical conclusion. Combine future versions of computer-managed systems like ESC, laser cruise control and active steering to ad hoc networks of cars on the road and global positioning, and the result is something like Toyota’s Vehicle Dynamics Management system. With this, Toyota postulates the development of cars that simply cannot crash.
For the time being, however, the computing power of cars has reached a point where current technologies can have a major impact on vehicle safety. If ESC is available on your next car, it’s a feature you’ll want to consider. Sure, it may take the steering wheel out of your hands for a few seconds in an emergency, but the majority of drivers are likely to accept all the help they can get.
Will that put Pierre Savoy and BMW Driver Training out of business? No, but just think how many people would graduate with flying colours.
Web driving
BMW Canada http://www.bmw.ca
Ford Canada http://www.ford.ca
Toyota http://www.toyota.ca
Audi http://www.audicanada.ca
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