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Prep Work: How Dealers Can Get a Jump on ESC Requirements

August 15, 2009
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Overall traffic fatalities reported in 2008 hit their lowest level since 1961.

The U.S. Department of Transportation released this statement in July. They went on to say, “that fatalities in the first three months of 2009 continued to decrease. The fatality rate, which accounts for variables like fewer miles traveled, also reached the lowest level ever recorded.”

As difficult as it is to admit, the advent and implementation of systems like electronic stability controls (ESC) and tire pressure monitoring systems may be part of the reason for the decline in deaths.

As an industry that has always had to overcome many unknowns with new technology, I’d say that we have all done a decent job of providing products and services to consumers despite the overwhelming obstacles that we face. 2009 and beyond will be no different.

Mimicking the progressive phase-in period when TPMS was implemented, ESC will reach the 30% mark Sept. 1, followed by 70% and finally 100% OE fitment in 2010 and 2011, respectively. One caveat though: the aftermarket gets one additional year to produce compliant components. This applies to specialty vehicle modifiers like Roush, Saleen and truck and van conversion companies, to name a few.

So what is ESC and why should I be concerned about it? It has been around for more than a decade and I haven’t had any trouble putting non-OE products on vehicles. To answer these questions, you will want to understand the evolution of ESC and how future versions will become much more than the original concept.

It all started with anti-lock braking systems (ABS). As we know, this is a passive system that doesn’t assist the driver until force is applied to the brake pedal. At that point, the ABS control module makes calculations to determine if the tires have lost traction and modulate to keep the brakes from locking up, which could potentially lead to a loss of driver control.

Next came traction control systems (TCS), which became prevalent during the late 1990s as a means to prevent roll over accidents in SUVs. Traction control was an important step in the evolution of vehicle control. It was an active system that could apply the brakes at any one corner without driver initiation. Also, the computer could decrease engine torque when it calculated that the tires were spinning. This was a tremendous step toward driver control on ice and snow, as well as wet roads.

Taking It Further
ESC is the next step. Now, computer control is based not just on speed sensors, but vehicle motion sensors. The computer models to determine the threshold for intervention rely on data from sensors regarding g-forces for lateral acceleration, yaw rate (vehicle rotational velocity), tire velocity and vehicle speed, steering wheel angle and throttle position angle, among others.

What does this all mean? The onboard computers are constantly measuring specific angles and parameters to verify that the driver has not attempted a maneuver that would cause them to lose control of the vehicle.

One example of this would be a lane change maneuver that was too abrupt, leading to an oversteer condition. To counter the effects, the ESC could activate the brake on the outside front, which would pull the front of the vehicle in the direction of the rear, thus preventing the vehicle from spinning around. To further augment the braking effect, it could reduce engine torque, as well.

Conversely, to overcome an understeer condition, ESC could apply the brake to the inside rear and potentially reduce engine torque.

The system also seeks to respond to the measured driver inputs and provide actions from the vehicle that are consistent with the “character” of the vehicle that the OEM was seeking to achieve.

Many of these systems are facilitated by what is known as “Drive by Wire,” wherein the driver doesn’t have a direct connection to the vehicle controls. We already see this with throttle sensors that “read” driver input and then tell the computer how much fuel and air is needed to produce the desired speed.

We have just begun to enter what many are calling the “X-by-Wire” era. This is the point where common controls such as steering and braking are not directly linked to the driver. Instead, sensors relay driver input to the computer, which, in turn, translates what the driver wants to accomplish into the appropriate, safe action.

When enhanced with proximity sensors, these systems are able to do incredible things like the parallel parking feature on the Lexus LS460. Just push a button and all of this technology performs the maneuver for you.

Also available in current model vehicles is lane departure warning and alcohol impairment detection. The former is handled by taking over the steering if a lack of certain movements of the steering wheel are detected and the latter is determined by sensors that actually read how often you blink and the duration that your eye lids are shut! And we thought the Batmobile had some crazy gadgets.

Working in Advance
As you can see, with all of this technology, there is some concern as to what happens when we have to put replacement tires on one of these vehicles. If the vehicle owner wants to upgrade the tires, wheels or suspension, how will we know that our actions will not cause a disruption with the ESC?

As detailed in this month’s Performance Training Guide article, I installed an H-rated tire on a Honda CR-V to increase lateral stability and provide the driver with better steering response.

For future vehicles equipped with ESC, we may have to quantify this to be able to recommend a replacement tire. If we choose a tire that doesn’t have very similar characteristics as the OE tire, we run the risk of the system not performing well or, worse yet, the ESC system limiting the overall performance of the aftermarket tire.

If this were to lead to an accident, you can bet that some ambulance-chasing lawyer will figure out that the new tires installed didn’t meet OE standards. Who do you think will be the first person named in the lawsuit?

With all of this being said, there is hope for us. John Waraniak, vice president of vehicle technology for SEMA, and Ed Browalski, SEMA vehicle technology consultant, are leading a cross-industry initiative to provide a computer simulation program and hardware-in-the-loop (HIL) vehicle systems methodology that will allow tire, wheel, brake and suspension manufacturers to simulate and test their products on a virtual vehicle without having to spend huge amounts of money to physically test their products on every vehicle model or platform.

SEMA is working in collaboration with several companies to develop HIL testing and simulation of aftermarket electronic stability control and modified vehicle dynamics performance. HIL testing effectively combines math model simulation with SEMA-member product data and plugs directly into a vehicle’s body and chassis electronic control modules. It’s the closest thing to physical testing, but at a fraction of the cost.

 To aid in this, SEMA has licensed CarSim software for its members from Mechanical Simulation. The simulation software is designed to collect data from multiple component sources. As the database grows, the analytical models will become more complete and more accurate. The objective is to develop a performance envelope for typical vehicle modifications, tires and wheel sizes and an accompanying grading system where individual products can be analyzed and a quantitative result derived that will indicate if the proposed product will meet or exceed the OE vehicle performance.  

According to Waraniak, “SEMA needs leading tire and wheel manufacturers to participate and take a proactive role in the development of the HIL program and methodology to help ensure representative components and data are being used in the simulations and vehicle dynamics performance evaluations.

“For instance, we would want to know the cornering ability of a specific tire expressed as a given performance metric,” he said. “From this, we can compare different tires to each other and offer statistically comparable replacement tires that will make sense to the consumer.

“We all know that we need to work together as an industry and take matters into our own hands to control our destiny and help secure the future of the specialty equipment and performance aftermarket,” said Waraniak.

If you doubt the validity of creating this performance envelope approach and ranking scale, for lack of a better term, then consider this: How many years have we been trying to convey that a V-rated tire should not be replaced with a S- or T-rated tire, only to have the consumer tell us, “I don’t drive that fast”?

I raise this challenge to every manufacturer that reads this column. Contact John Waraniak at johnw@sema.org 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 will be an in-depth seminar on vehicle dynamics on Nov. 5. Plans are to demonstrate HIL technology and how the CarSim software can be utilized.

We have one chance to get this right, let’s not blow it!