Using a single vehicle fitted with a water-spewing contraption, engineers are able to replicate the vehicle dynamics associated with a car-to-car crash.
On a sunny May afternoon, a Ford engineer holds the accelerator steady at 50 mph (80 km/h) during a circular turn on dry pavement. Immediately after two red steering wheel buttons are depressed, nearly 10 gal (38 L) of water blasts from the passenger-side rear compartment of a Volvo V70R AWD, jolting the back end in a sideways skid.
"That large jet of water being sprayed creates a substantial yaw into the vehicle as if it were being hit in the rear quarter," said Steve Kozak, Chief Engineer of Ford Motor Co.'s Global Safety Systems. This unusual test could help Ford engineers develop next-generation stability control technology.
"We want to answer the question 'what happens to a car after an initial crash?' so we can determine if there is something we can do to help the driver regain control of the car before there is a second event," said Jeffrey Rupp, Manager of Active Safety, Research, and Advanced Engineering at Ford.
Rupp, the inventor of the water cannon, said the experimental test presents a low-risk way of simulating a car-to-car crash. The water cannon-equipped test vehicle is slated for instrumentation with accelerometers and sensors to record steering wheel position, throttle position, brake position, and other relevant data points.
"We have some initial ideas on control algorithms that we can try as well as some simulations that look promising," said Rupp, adding, "We don't have any solid conclusions yet as we just started using this testing tool in December 2008, so in a certain respect this testing method is a research project."
Dubbed a Light Vehicle Impact Simulator (LVIS), the test rig uses an air cylinder (charged to 130 psi [9 bar]) to propel water from a cylinder. The Volvo V70R test vehicle is minus the back windows and rear seat. "When we're ready to start running calibrated tests, then we'll access the exact mass and inertial characteristics of the car and set it up properly," said Rupp.
Using a single car to simulate a car-to-car crash presents tangible benefits: the test driver is essentially at zero risk for injury, and the test vehicle is essentially risk-free of being damaged. "We really don't know of another automaker that is doing anything quite like what we're doing to simulate a car-to-car collision," Rupp said.
Ford researchers are continually developing new ways to conduct tests. "In the active safety engineering group alone, we probably have 15 major projects and a bunch of other minor projects going on and each has many different phases of concept development, simulation, prototyping, testing, and evaluation," Rupp said.
Tests done at Ford for active safety technologies have led to the deployment of more than 4 million Electronic Stability Control (ESC) systems on vehicles worldwide. Ford officials expect to have all new Ford, Lincoln, and Mercury vehicles equipped with ESC by year's end.