What do heavily-laden grocery carts, rear-mounted water cannons and lead-tipped whips have to do with increasing the level of passenger protection in new cars? According to the folks at Ford, plenty. The automaker uses all three to commit various forms of automotive assault and battery on its latest products to ensure that the passive safety systems respond properly in the event of a side impact. The goal is to make sure that the side airbags deploy if -- but only if -- needed, and not merely in reaction to lesser hits, such as those generated by a too-close encounter with a shopping cart, an errant bicycle or a severely distressed road surface.
According to Sue Cischke, group vice president, Ford Sustainability, Environment and Safety Engineering: "Blasting and ramming cars may seem over the top, but they're part of a serious testing regimen that Ford had to invent, because increasingly sophisticated technologies require more advanced testing." The need for these somewhat unorthodox techniques is the direct result of the automaker adopting a new strain of airbag sensors that rely on pressure pulses rather than conventional accelerometer data to determine whether a deployment is required.
Pressure-based sensors can more accurately measure crash severity, which gives them an advantage both in federal side- and oblique-impact testing as well as in real-life crashes. They're also smaller, which makes them easier to package in a variety of different vehicles -- notably the 2009 Ford F-150 pickup and the new 2010 Ford Taurus sedan which pioneer their use. These pulse sensors can trigger up to 30-percent quicker bag deployments but require even more sophisticated calibration to prevent them from being tricked into firing when not needed.
The barrage of tests Ford uses to determine the appropriate threshold trigger currently involves ramming a shopping cart with 110 pounds of ballast into the vehicle's door at 10 mph and repeatedly running into it with the tire from a virtual bicycle. Beyond dynamic evaluation over potholes and railroad tracks, Ford technicians devised a special multi-tailed lead-tipped whip that aggressively whacks the vehicle's underbody near where the side airbag sensors are located. Arguably the most amusing of these devices to watch in action is a transversely mounted pneumatic water cannon. Positioned to fire outward with sufficient force to induce an immediate severe skid, it helps Ford engineers determine how to optimize operation of the electronic stability control system. Who says work can't be fun?