Have Dyno, Will Travel - Visteon dynamometer

Automotive Manufacturing & Production, July, 2001

Frank Silvagi, supervisor of Noise, Vibration, and Harshness (NVH) systems at Visteon, points to the laser beneath the SUV undergoing testing on the portable NVH dynamometer Visteon developed. "One of the advantages we have is that we use a laser measurement system, which means we don't waste a lot of time setting up and breaking down equipment and that saves development time," he says. Doing things the old way meant technicians spent half a day cementing accelerometers to the vehicle, and another half day taking them off, tearing down the test equipment, and putting everything away. "Now we can do basic set-up in about an hour," says Silvagi, "so many tests can be completed in one day, start to finish, instead of two or more.

The laser also removes the problem of altering the measurements by adding the measuring equipment. Think of it as an automotive version of the Heisen-berg Uncertainty Principle: the simple act of measuring something changes it. In this case, the accelerometers could damp or increase the vibrations through their contact with the vehicle. Because light is being used, "there's much less chance that we are adding, or subtracting, anything from the system," says Silvagi.

The speed with which the portable dyno can be set up (pull into place, extend the sides, load the vehicle and lock it down, set up the measuring equipment, calibrate the system) is a major selling point. "We can go to a plant and measure 30 vehicles in one week," says Silvagi. "That wasn't possible before."

Each vehicle can be "fingerprinted" at speeds from 20-90 mph in about 20 minutes. Additional tests-like horsepower measurement, two-plane system balancing, cruise speed evaluations, and subjective ratings-usually can be accomplished in less than one hour.

"You can also swap out parts and do hardware comparisons without having to dismantle everything," he says. "This makes it easy to compare drive-line components back-to-back, or do engine modifications without having to go through multiple set ups."

The information is fed into an onboard computer system located in the office at the front of the trailer. "The analysis is usually ready by the time the vehicle is coming off the rollers, and we can either meet with the customer here, or take the laptop to their office for further discussions" says Silvagi.

Visteon's portable dyno can handle vehicles with wheelbases from 85 to 190 in., though pickups with dual rear wheels are too wide to fit comfortably. Front-, rear-, two-wheel, four-wheel and all-wheel drive layouts can be accommodated, as can roller speeds up to 200 mph. "We've had a few NASCAR teams use it," says Silvagi.

"We also think this unit will be useful at the start of a new vehicle program," says Silvagi. "You can use it to measure the current vehicle, and determine where you need to make improvements in its noise and vibration attributes before you get too far along with the new one." This information can be archived, and compared with vehicle drivelines and powertrains from target vehicles if desired.

The Visteon portable dynamometer has tested well over 2,000 vehicles in its short lifetime, with more to follow. Two patents are pending, and one has been issued for the unit. Featherlite trailers provides the trailer unit under an exclusive three-year agreement, while Dynojet has a similar arrangement for use of the onboard dynamometers. To learn more, you can check out this website: www.visteon.com/portabledyno.>

COPYRIGHT 2001 Gardner Publications, Inc.

COPYRIGHT 2001 Gale Group