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Harley-Davidson: the sound of a legend; NVH technology helps deliver what riders want to hear. (Product).

You know it's a Harley as soon as you hear it, before you even see it.

The throaty pounding and off-centered drumming beat are part of the signature sound that defines the persona of the machine and differentiates the manufacturer from its competitors.

It's all about the thunder, roar and rumble riders expect when they rev up the engine.

"Our product is identified just as much by how it sounds as how it looks," explains Alex Bozmoski, manager of the company's noise, vibration and harshness (NVH) development facility. "Sound quality is critical in establishing the image of a Harley-Davidson motorcycle and in personifying the perception of quality to the rider."

"The experienced Harley community demands a certain distinctive and unmistakable sound," he adds. "The sound is a major part of the brand value our products bring to the market."

NVH must "preserve and enhance" the Harley sound, Bozmoski says. But it must also meeting strict domestic and international noise regulations.

"You could easily put covers and cowlings over the powertrain to tailor mechanical noise or balloon up the intake and exhaust system to meet regulatory noise requirements," says Bozmoski. "Automotive manufacturers do that in their vehicle designs all the time, as do many of our competitors."

But hiding the engine and other systems would violate the all-important look of a Harley. Instead, he says, Harley engineers the sound into the machine with just the right balance of tone, pitch, and beat from the intake, exhaust, engine and drivetrain.

NVH leaves in the desirable sounds while damping out whines, whirs, ticks, knocks, and other unwanted mechanical noises.

The group also is responsible for the unique feel of each Harley model.

"Vibration at all the operator interface points is an important part of the riding experience,' notes Bozmoski. "We pay very close attention to the frequency and amplitude of excitation wherever the rider and machine interface: handlebars, seat and footpegs."

With NVH being such a vital part of Harley's character it is integrated into each Harley's product development from the beginning. Each core product development team has NVH representation at inception so all processes including design, predictive analysis, development and validation can consider NVH.

"We're not so much focused on fixes at the end of development but rather on solutions throughout development, especially in the early conceptual stages where important decisions are made about the configuration of the product," he says.

NVH is included in product development at its inception where all the processes can be tied together: design, predictive analysis development, and validation.

Harley, says Bozmoski, has moved away from troubleshooting at the end of the development cycle to more of a collaborative cross functional design process.

NVH also works with suppliers on component-level development. In some cases HVH experts have advised powertrain engineers o' the sound-quality consequences of changing the clearance of parts by as little as one-tent housandths of an inch.

Throughout the development process the NVH team uses CADA-X acoustic and vibration testing software from LMS.

Software modules running on a bay 01 workstations and high-speed multi-channel front-ends perform data-acquisition and a wide range of analyses including advanced acoustics, signature analysis, modal analysis and time wave replication.

General utility programs EMON and TMON are used to correlate data and perform comparative studies. SYSNOISE is used for predicting and visualizing sound envelops around individual components and sub assemblies as well as full vehicles.

Harley also has advanced modules such as Kalman filtering, synchronous re-sampling, time-frequency analysis and acoustic holography.

Some of the software has been customized to include standard processes and routine procedures used in modeling structures, analyzing results, and handling data.

"This saves us time and standardizes operations from project to project," Bozmoski says. "Moreover, embedding these processes and procedures in software captures this knowledge base so it can be leveraged later."

The software allows Harley to present easily identifiable results that can be shared across the organization, he says.

"These solutions are central to our strategy of maintaining the classic sound of a Harley while improving performance, respecting the legendary look of the machine and meeting strict noise regulations," he explains. "Our most important assets at Harley-Davidson are our employees and the expertise and passion they have for the product. LMS technology lets us leverage those assets in delivering the legendary riding experience our customers expect and deserve."

RELATED ARTICLE: Harley's state-of-the-art NVH lab.

At the core of Harley-Davidson's NVH expertise is a state-of-the-art NW Development Center, a part of the Willie G. Davidson Product Development Center in Wauwatosa, Wisconsin, just outside Milwaukee. Closed to the public as well as most of the non-engineering personnel at the company, the first stage of the facility was completed in 1997 as one of the top NVH test facilities in the world.

The lab includes a fully anechoic chamber for engine and transmission studies as well as a semi-anechoic chamber with a 160 hp chassis-dyno for full vehicle testing. These test cells are equipped with automated-sequence, remotely-controlled arrays of microphones for gathering acoustic-intensity and acoustic-holography data while sensors record engine vitals, vibration levels and a host of other test related information.

The facility also has a jury listening chamber where people from across the company are. selected to judge the sound quality of proposed designs. This provides a correlation between rider preferences and product performance.

"Jury evaluations are typically done with experienced riders throughout our organization," says Alex Bozmoski, manager of the company's noise, vibration and harshness (NVH) development facility. The constituency might include people from senior management as well as accounting, marketing, sales, engineering, or shipping. We strive for a good: cross-section to reflect 'a range of opinions and preferences. We also conduct off-site jury tests with our customers to validate our process."

The Harley legacy.

Few products have such a loyal following as Harley-Davidson. The Harley Owners Group (HOG) numbers more than 660,000 in 115 different countries; making it the largest motorcycle enthusiasts club in the world. The members are passsionate for the machines and their demand that the bikes retain the characteristic sound these heavyweight motorcycles have had since William. Harley and Arthur Davidson built their first one in 1903.

They must be doing something right. Since the firm went public n 1986, earnings have averaged 37' percent growth. And in a year economic downturn when many manufacturers are scratching just to get, by, sales Harley-Davidson Motorcycle Co. grew 15.7 percent to reach $3.36 billion in' 2001; The company builds more than 200,000 bike annually and sells everyone. Forbes' magazine named Harley-Davidson "Company the Year" for 2001, and the newly introduce V-Rod (Harley's first liquid-cooled production model)' has been named "Bike of the Year" b Motorcycle News. magazine.
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Title Annotation:noise, vibration and harshness
Publication:Automotive Industries
Geographic Code:1USA
Date:Nov 1, 2002
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