Tuesday, September 14, 2010

Electronic Stability Control

Electronic Stability Control (one of the most significant automotive safety features to appear in the past 20 years) will become mandatory on all new passenger vehicles built and sold in Canada after Sept. 1, 2011.  If you are driving a late model SUV, you probably already have such a system on your vehicle but some of the most popular passenger cars are just starting to be built with this feature as standard equipment.

Many Names, Same Function
You should note that Stability Control has many commercial names. At GM, it's called StabiliTrak, Mazda calls it DSC (Dynamic Stability Control) while it's ESP (Electronic Stability Program) at some other manufacturers.   You may also see it called VSC for Vehicle Skid Control.  Whatever the trade name, Electronic Stability Control seeks to automatically reduce speed and judiciously apply braking power to one or more wheels to avoid a skid and loss of driver control.  Electronic Stability Control, however, isn't exactly new, especially to buyers of luxury Mercedes-Benz vehicles where it was originally developed and brought to market in the 1990's.

Since then, all car makers offer an Electronic Stability Control system which is designed to activate when the vehicle is taking a turn too quickly for the road conditions.  The ESC compares the driver's intended direction (from the steering wheel angle) to the actual vehicle path; if the system senses understeer or oversteer, it applies braking force (using the ABS - antilock braking system), and reduces engine torque if required, to correct the situation.

These traction control systems generally come in one of two primary systems: an ABS-based system, or an engine management system. Both systems use the ABS wheel speed sensors to determine if there is wheel spin (wheel speed greater than vehicle speed).  Top end SUVs use engine management to reduce the amount of power output by reducing fuel, ignition timing and throttle position to reduce wheel slippage. More basic systems use the ABS brakes to slow down the spinning wheel – ABS systems have a tendency to be very jarring in their operation and can overheat the brakes if used for extended periods of time. Vehicles employing a Traction Control System (TCS) in conjunction with ESC can deal with the problem of the engine supplying too much power for road conditions right at the source.  When wheel spin is detected, the TCS simply reduces the engine’s power output until the wheel slippage stops.

There are no additional maintenance requirements for stability control, which basically piggybacks on sensors in a vehicle's four wheels that operate the anti-lock brake system and also can intervene on throttle control.  If your vehicle becomes stuck in deep snow, however, automakers generally advise that you turn off stability control (there's usually a deactivation button on the dashboard) in order to get the full power of the engine and wheel spin as you try to work your vehicle free.

Studies Prove It Can Save Your Life
A number of independent studies conducted around the globe have shown that stability control can help drivers maintain directional control and have fewer single-vehicle crashes, in particular.   NHTSA in Washington, D.C., in fall 2006 chose to give stability control the official thumbs up while giving automakers another half dozen years (to model year 2012) to make this important safety feature standard.

Even if you think you are a great driver, Electronic Stability Control will work in the background to correct for driving mistakes and judgment errors, making you a better driver.  It might even save your life without you knowing it!