Overall traffic fatalities reported in 2008 hit their lowest level since 1961.
TheU.S. Department of Transportation released this statement in July. Theywent on to say, “that fatalities in the first three months of 2009continued to decrease. The fatality rate, which accounts for variableslike fewer miles traveled, also reached the lowest level ever recorded.”
Asdifficult as it is to admit, the advent and implementation of systemslike electronic stability controls (ESC) and tire pressure monitoringsystems may be part of the reason for the decline in deaths.
Asan industry that has always had to overcome many unknowns with newtechnology, I’d say that we have all done a decent job of providingproducts and services to consumers despite the overwhelming obstaclesthat we face. 2009 and beyond will be no different.
Mimickingthe progressive phase-in period when TPMS was implemented, ESC willreach the 30% mark Sept. 1, followed by 70% and finally 100% OE fitmentin 2010 and 2011, respectively. One caveat though: the aftermarket getsone additional year to produce compliant components. This applies tospecialty vehicle modifiers like Roush, Saleen and truck and vanconversion companies, to name a few.
So what is ESC and whyshould I be concerned about it? It has been around for more than adecade and I haven’t had any trouble putting non-OE products onvehicles. To answer these questions, you will want to understand theevolution of ESC and how future versions will become much more than theoriginal concept.
It all started with anti-lock braking systems(ABS). As we know, this is a passive system that doesn’t assist thedriver until force is applied to the brake pedal. At that point, theABS control module makes calculations to determine if the tires havelost traction and modulate to keep the brakes from locking up, whichcould potentially lead to a loss of driver control.
Next cametraction control systems (TCS), which became prevalent during the late1990s as a means to prevent roll over accidents in SUVs. Tractioncontrol was an important step in the evolution of vehicle control. Itwas an active system that could apply the brakes at any one cornerwithout driver initiation. Also, the computer could decrease enginetorque when it calculated that the tires were spinning. This was atremendous step toward driver control on ice and snow, as well as wetroads.
Taking It Further
ESCis the next step. Now, computer control is based not just on speedsensors, but vehicle motion sensors. The computer models to determinethe threshold for intervention rely on data from sensors regardingg-forces for lateral acceleration, yaw rate (vehicle rotationalvelocity), tire velocity and vehicle speed, steering wheel angle andthrottle position angle, among others.
What does this allmean? The onboard computers are constantly measuring specific anglesand parameters to verify that the driver has not attempted a maneuverthat would cause them to lose control of the vehicle.
Oneexample of this would be a lane change maneuver that was too abrupt,leading to an oversteer condition. To counter the effects, the ESCcould activate the brake on the outside front, which would pull thefront of the vehicle in the direction of the rear, thus preventing thevehicle from spinning around. To further augment the braking effect, itcould reduce engine torque, as well.
Conversely, to overcomean understeer condition, ESC could apply the brake to the inside rearand potentially reduce engine torque.
The system also seeks torespond to the measured driver inputs and provide actions from thevehicle that are consistent with the “character” of the vehicle thatthe OEM was seeking to achieve.
Many of these systems arefacilitated by what is known as “Drive by Wire,” wherein the driverdoesn’t have a direct connection to the vehicle controls. We alreadysee this with throttle sensors that “read” driver input and then tellthe computer how much fuel and air is needed to produce the desiredspeed.
We have just begun to enter what many are calling the“X-by-Wire” era. This is the point where common controls such assteering and braking are not directly linked to the driver. Instead,sensors relay driver input to the computer, which, in turn, translateswhat the driver wants to accomplish into the appropriate, safe action.
Whenenhanced with proximity sensors, these systems are able to doincredible things like the parallel parking feature on the Lexus LS460.Just push a button and all of this technology performs the maneuver foryou.
Also available in current model vehicles is lanedeparture warning and alcohol impairment detection. The former ishandled by taking over the steering if a lack of certain movements ofthe steering wheel are detected and the latter is determined by sensorsthat actually read how often you blink and the duration that your eyelids are shut! And we thought the Batmobile had some crazy gadgets.
Working in Advance
Asyou can see, with all of this technology, there is some concern as towhat happens when we have to put replacement tires on one of thesevehicles. If the vehicle owner wants to upgrade the tires, wheels orsuspension, how will we know that our actions will not cause adisruption with the ESC?
As detailed in this month’sPerformance Training Guide article, I installed an H-rated tire on aHonda CR-V to increase lateral stability and provide the driver withbetter steering response.
For future vehicles equipped withESC, we may have to quantify this to be able to recommend a replacementtire. If we choose a tire that doesn’t have very similarcharacteristics as the OE tire, we run the risk of the system notperforming well or, worse yet, the ESC system limiting the overallperformance of the aftermarket tire.
If this were to lead toan accident, you can bet that some ambulance-chasing lawyer will figureout that the new tires installed didn’t meet OE standards. Who do youthink will be the first person named in the lawsuit?
With all ofthis being said, there is hope for us. John Waraniak, vice president ofvehicle technology for SEMA, and Ed Browalski, SEMA vehicle technologyconsultant, are leading a cross-industry initiative to provide acomputer simulation program and hardware-in-the-loop (HIL) vehiclesystems methodology that will allow tire, wheel, brake and suspensionmanufacturers to simulate and test their products on a virtual vehiclewithout having to spend huge amounts of money to physically test theirproducts on every vehicle model or platform.
SEMA is workingin collaboration with several companies to develop HIL testing andsimulation of aftermarket electronic stability control and modifiedvehicle dynamics performance. HIL testing effectively combines mathmodel simulation with SEMA-member product data and plugs directly intoa vehicle’s body and chassis electronic control modules. It’s theclosest thing to physical testing, but at a fraction of the cost.
Toaid in this, SEMA has licensed CarSim software for its members fromMechanical Simulation. The simulation software is designed to collectdata from multiple component sources. As the database grows, theanalytical models will become more complete and more accurate. Theobjective is to develop a performance envelope for typical vehiclemodifications, tires and wheel sizes and an accompanying grading systemwhere individual products can be analyzed and a quantitative resultderived that will indicate if the proposed product will meet or exceedthe OE vehicle performance.
According to Waraniak, “SEMA needsleading tire and wheel manufacturers to participate and take aproactive role in the development of the HIL program and methodology tohelp ensure representative components and data are being used in thesimulations and vehicle dynamics performance evaluations.
“Forinstance, we would want to know the cornering ability of a specifictire expressed as a given performance metric,” he said. “From this, wecan compare different tires to each other and offer statisticallycomparable replacement tires that will make sense to the consumer.
“Weall know that we need to work together as an industry and take mattersinto our own hands to control our destiny and help secure the future ofthe specialty equipment and performance aftermarket,” said Waraniak.
Ifyou doubt the validity of creating this performance envelope approachand ranking scale, for lack of a better term, then consider this: Howmany years have we been trying to convey that a V-rated tire should notbe replaced with a S- or T-rated tire, only to have the consumer tellus, “I don’t drive that fast”?
I raise this challenge to every manufacturer that reads this column. Contact John Waraniak at [email protected] or 248-363-5313 and discuss what part of the equation you can contribute to.
Also,for those who will be attending the SEMA Show in November, there willbe an in-depth seminar on vehicle dynamics on Nov. 5. Plans are todemonstrate HIL technology and how the CarSim software can be utilized.
We have one chance to get this right, let’s not blow it!