Overall traffic fatalities reported in 2008 hit their lowest level since 1961.
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.”
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.
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.
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
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.
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
Taking It Further
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.
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
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.
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
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
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.
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.
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.
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.
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 firstname.lastname@example.org
or 248-363-5313 and discuss what part of the equation you can contribute to.
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!