Few products have such a loyal following.
The Harley Owners Group (HOG) numbers more than 660,000 in 115 different countries, making it the largest motorcycle enthusiasts club in the world. They certainly don’t hide their passion for the machines or their demands that the bikes retain the characteristic sound these heavyweight motorcycles have had since William Harley and Arthur Davidson built their first one in 1903.
The company must be doing something right in satisfying this discerning customer base. Since the firm went public in 1986, earnings have averaged 37% growth.
And in 2001, a year of economic downturn when many manufacturers were scratching just to get by, sales at1Harley-Davidson Motorcycle Co. grew 15.7 % to reach $3.36 billion in 2001. The company builds more than 200,000 bikes annually and sells every one. Forbes magazine named Harley-Davidson “Company of the Year” for 2001.
Sculpting the noise
“Our product is identified just as much by how it sounds as how it looks,” explains Alex Bozmoski, manager of the company’s 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-Davidson community demands a certain distinctive and unmistakable sound. The sound is a major part of the brand value our products bring to the market.”
The responsibility of NVH Development is to “preserve and enhance” the characteristic identified as the Harley-Davidson Sound, all while improving performance with latest design enhancements and continuing to meet strict domestic and international noise regulations. This is clearly no simple task, since the company is constantly adding new technology to its designs to improve engine and drivetrain performance, ride quality, handling, and durability.
“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. Hiding the engine and other systems would violate the look of the Harley. So instead we engineer the sound into the machine: sculpting the noise to produce just the right balance of tone, pitch, and beat from the intake, exhaust, engine, and drivetrain.”
The expertise of the NVH group is in knowing how to accentuate the desirable sounds while damping out whines, whirs, ticks, knocks, and other unwanted mechanical noises. The group is
also responsible for the unique “feel” of each 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.”
At the Harley-Davidson Product Development Center in Wauwatosa, Wisconsin, motorcycle designers and NVH personnel work closely together throughout the product lifecycle.
Cross-functional development
Such corporate knowledge of NVH is considered a valuable intellectual asset at Harley, and efforts are concentrated on tightly integrating this discipline into the entire product development process. “We’ve aggressively moved from a tribal way of working to a cross-functional approach where each core product development team has NVH representation,” says Bozmoski.
This approach facilitates the application of knowledge concerning NVH requirements from concept through production, according to Bozmoski. “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 when important decisions are made about the configuration of the product,” he says.
“To do this, NVH is included in product development at its inception, when the process can be tied together: design, predictive analysis, development, and validation. We’ve definitely moved away from time-consuming troubleshooting at the end of the development cycle to more of a collaborative cross-functional design process.”
Bozmoski notes that the NVH group participates in the design of the entire product, including component-level development. He can cite several cases where the NVH staff advised powertrain engineers of the sound-quality consequences of changing the clearance of parts by as little as one-tenthousandths of an inch.
State-of-the-art NVH development facilities
Harley-Davidson’s commitment to sound quality in its products is evidenced by the company’s investment in a state-of-the-art NVH Development Center, a part of the Willie G. Davidson Product Development Center in Wauwatosa, Wisconsin, just outside Milwaukee. Completely closed to the public as well as to most of the company’s non-engineering personnel, the first stage of the secure facility was completed in 1997 as one of the premier 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 160HP 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 all disciplines in the company are selected to assess the sound quality of proposed designs, thus providing a correlation between rider preferences and product performance.
“Jury evaluations are typically done with experienced riders throughout our organization,” Bozmoski explains. “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.”
Leveraging expertise and passion
For their NVH work, Harley-Davidson has assembled some of the most powerful software solutions available. At the heart of this setup is LMS CADA-X for acoustic and vibration testing. Software modules running on a powerful bay of workstations and high-speed multichannel 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 FMON and TMON are used to correlate data and perform a variety of comparative studies. SYSNOISE is used for predicting and visualizing sound envelops around individual components and subassemblies as well as full vehicles. Harley-Davidson also has advanced modules such as Kalman filtering, synchronous re-sampling, time-frequency analysis, and acoustic holography.
According to Bozmoski, 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,” he says. “Moreover, embedding these processes and procedures in software captures this knowledge base so it can be leveraged later. Otherwise, it’s buried in a file and soon forgotten. Commonization through customization allows us to present easily identifiable results. That promotes an ability to share our expertise across the organization.”
Asked how the NVH group would do its work without LMS software, Bozmoski responds: “Achieving the quantity and quality of advanced NVH engineering we reach today in the time-frame in which we are expected to deliver would not be possible without the analysis power provided by the high-speed, multichannel technology at our disposal.
These solutions are central to our strategy of maintaining the classic sound of a Harley-Davidson 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.”
