New technologies can beget solutions or challenges, depending on which side of the vehicle you're on.
One technology that is touted as the best automotive safety feature since seat belts-and promises to save thousands of lives-is electronic stability control (ESC). It could become standard equipment on all new vehicles by 2011 under a federal government proposal announced Sept. 14.
The system is part of a growing trend in the automotive industry to add sensors and electronic control functions to mitigate crash severity by having the vehicle react with passive and/or active safety measures before a collision occurs.
While tire and automotive service technicians may not be servicing these so-called ``pre-accident'' systems yet themselves, they should be aware of their presence on a vehicle, read technical service bulletins (TSBs) about recalibration and prepare for additional undercar electronics in the future.
At the forefront of the automotive industry's safety push is ESC, an extension of anti-lock brake technology designed to reduce the occurrence of rollovers and crashes when a driver loses control of a vehicle and overcompensates the steering, usually on curves and turns.
Under its recently proposed rule, the National Highway Traffic Safety Administration would require all auto manufacturers to equip passenger vehicles weighing less than 10,000 pounds with ESC starting with the 2009 model year and make it standard equipment on all vehicles by the 2012 model year.
The Insurance Institute for Highway Safety found that ESC reduces the risk of fatal multiple-vehicle crashes by 32 percent and reduces the risk of all single-vehicle crashes by more than 40 percent and fatal ones by 56 percent. The institute believes ESC should be standard on all vehicles based on its estimates that if all vehicles were equipped with ESC, as many as 10,000 fatal crashes could be avoided annually.
ESC is standard on 40 percent of the 2006 passenger vehicle models-mostly high-end makes, including Audi, BMW, Infiniti, Mercedes and Porsche. ESC is optional on another 15 percent, including Cadillac, Jaguar, Land Rover, Lexus, Mini, Toyota, Volkswagen and Volvo.
Offered by various manufacturers under different trade names, ESC systems help the vehicle maintain control during extreme steering maneuvers by sensing when a vehicle is starting to oversteer or understeer.
ESC uses several sensors to continuously monitor the vehicle's response to the driver's steering wheel input. An ESC system can include a yaw rate sensor, lateral accelerometer, steering angle sensor and wheel speed sensors to modulate brake pressures and adjust engine torque.
It can detect a loss of traction during high-speed maneuvers or on slippery roads, then works with the anti-lock brakes to help the vehicle stay on its intended path. As the vehicle begins to spin or skid, the ESC pulsates the brakes of individual wheels to help ``rotate'' the vehicle to the driver's intended path.
Another pre-accident system that is becoming optional equipment on passenger vehicles is the adaptive cruise control (ACC). This system uses forward-looking radar, usually installed behind the car's grill, to detect the speed and distance of the vehicle ahead of it. Similar to conventional cruise control in maintaining the vehicle's pre-set speed, ACC uses a long range radar sensor to detect a target vehicle up to 650 feet in front and automatically adjusts vehicle speed and distance behind the front vehicle.
Using a radar headway sensor, digital signal processor and longitudinal controller, the system slows the vehicle down if the vehicle in front slows down or if another object is detected. When the path is clear, the system will re-accelerate the vehicle back to the set speed.
TRW Automotive Holdings Corp. has added a traffic jam assistant stop-and-go function to its ACC system by using additional short-range radars to cover a wider field in front of the vehicle. ACC permits the vehicle to follow a vehicle in front automatically at a set distance in a traffic jam situation and enables braking to a complete stop.
Delphi Corp., likewise, has developed a system for congested roads that includes a forward collision warning function. The system automatically maintains driver selected headway-between 1 and 2.2 seconds-using throttle control and limited braking. If the gap is closing quickly, requiring manual intervention, the system emits audible and visual warnings.
Continental Automotive Systems has similar systems, and like other original equipment manufacturers, is working on other pre-accident systems, such as lane departure warnings and enhanced parallel parking assistance.
``Undercar electronics is increasing rapidly, and I don't see any reason why it will stop,'' said Philip Headley, chief engineer for advanced technology at Continental Automotive. He noted there are numerous ideas for other electronic systems to add to the vehicle for safety and for driving enjoyment.
Dan Milot, TRW chief engineer, agreed. ``Every year there is considerable more content in the chassis.'' He noted that ESC will become the central hub to the whole integration of various safety systems in a vehicle.
As with most new technologies, each supplier has its own version along with its own requirements for repairing and calibrating them.
While these new technologies might represent another headache for repair shops, Denny Bowen, Hunter Engineering Co.'s director of product management, has a more positive take. ``I consider it an opportunity and a bit of a challenge.''
Still, there are some inherent quirks to all this inner-electronic-system dependency.
When adjusting the alignment, especially with the rear suspension, if the technician changes the thrust angle, the steer angle sensor or the ACC radar sensor may need to be retrained or recalibrated depending on the vehicle manufacturer requirements, according to Mr. Bowen.
While failure to do so wouldn't cause a safety issue, a customer might complain about turning hard left and feeling the car shudder as it tries to compensate for what it thinks is an uncontrolled oversteer situation, Mr. Bowen said.
``It's a comeback situation, not a problem that can't be fixed,'' he said, adding, ``The problem is not the result of design of the vehicle or not the work done on it, but what is missing between the two. The missing link is information and equipment.''
Mr. Bowen's advice to tire dealerships is to read all the TSBs on these systems and put that information at the front service desk. Before writing up a customer's order, the service writer needs to ask: ``A: What are the special procedures (for a system)? And B: What specific tools or other things are needed? Otherwise you have a car on the rack you can't complete,'' Mr. Bowen said.
``There are plenty of bulletins out there,'' he noted. ``But people are not used to looking at bulletins for undercar work. It all begins at the service counter. You have the information available so you can make good decisions and talk to the vehicle owners. That's really key.''
Because the systems differ from manufacturer to manufacturer, some need more adjustments than others and some require specific OEM scan tools, which can be expensive. ``All shops have scan tools,'' Mr. Bowen said, ``but the problem is, do they have the right one?''
Yet he believes that problem will disappear as technologies mature.
``As time goes on, things have a habit of going mainstream. When it's new, everyone has their own way of doing it,'' he said. ``That's what is causing the confusion.'' He expects ESC systems will become mainstream in about five years due to their popular safety benefits. The adaptive cruise control is not as popular right now, so it may take longer to become commonplace.
Conti's Mr. Headley said he believes tire and undercar servicing shouldn't have any impact on the ESC and ACC systems unless the work deals directly in the area of the sensors, such as removing the front grill, which houses the ACC radar sensors or replacing wheel bearings that have built-in speed sensors.
TRW's Mr. Milot said the OEM's intent was to make these systems transparent to undercar techs and thus their work shouldn't impact these self-adjusting systems. But he did note that techs will need to become more computer savvy as vehicles become less mechanical and more electronic. Many systems are capable of diagnosing problems by giving codes to diagnostics tools to locate the problem.
Tire dealers should be aware that there are limits to plus-sizing the wheels with ESC-equipped vehicles, as the systems are calibrated for the specific model dimensions.
If a vehicle owner wants to do an extreme plus-sizing, the dealer will simply have to say, ``I can't do that,'' Mr. Headley said. ``I'm nervous about people with 30-inch wheels on a Jeep.''
Ed Bedner, a Delphi staff research engineer, noted that ESC systems are self-contained and designed to function with the OE tires. He noted that tires' features change as they are driven, and the ESC is designed to account for those natural tire changes.
However, if there is radical change or gross underinflation, the ESC will not work properly. Replacement tires should fall within the vehicle manufacturer's recommendations with small variations allowed.
TRW is working with Goodyear on an ESC system that would compensate for some plus-sizing. The system would automatically adjust its performance parameters based on the dimensions and other characteristics of a vehicle's ``talking tires''-which would communicate with the system via an imbedded RFD chip. TRW said the system, targeted for 2009 production models, would especially benefit sport-utility vehicles mounted with winter tires or custom wheels and large diameter tires.
Tire dealers need to have a positive outlook to changing technology, Mr. Bowen said, recalling how, in the 1980s, the industry introduced distributor-less ignitions. That caused virtual panic among some shop owners who thought it would ruin their businesses. ``Change occurs-some approach it right and some don't,'' he said.