Many supplier companies cannot justify the investment of a full-scale dynamometer facility – yet they still have to troubleshoot NVH problems and tune their components to a vehicle. As a supplier themselves, Visteon understood the challenge. They developed a unique solution: the Visteon Portable NVH Dynamometer, which is used to provide a complete self-contained service at the client site. The dynamometer is equipped with non-contact laser technology and LMS CADA-X systems: tests can be completed just twenty minutes after the vehicle drives up the ramp...
The Mobile Lab Innovation
Frank Silvagi, Supervisor of NVH Development at Visteon, says that the mobile lab concept was a response to a market need they identified in 1998: many OEM production plants and supplier companies needed to refine the NVH performance of their products, but lacked the resources and experience to do it themselves. They needed the laboratory to come to them.
No one else in the industry offered a mobile service, and now Visteon engineers not only perform the tests on-site, but cover the full range of analyses from prototype and pre-production audits, benchmarking and target setting; to root cause analysis and troubleshooting for production issues… In the case of a production facility, a typical mission would be to support quality audits by taking 45 vehicles off the assembly line at random, and delivering a production snapshot to compare to standards and benchmarks. A typical troubleshooting application is for driveline imbalance evaluations. By helping their customers meet NVH targets for regulations and design, the Mobile Dyno Lab has become an added customer service for Visteon. The first rig fitted the NVH needs of their customers so closely that they had to add a second lab this summer to cover North America (in 27 months alone they visited 34 assembly plants), and they are now setting up a third in Europe.
Fast, non-damaging, comprehensive NVH testing
The speed at which the mobile lab can test cars is one of its strongest benefits. Prior to the mobile lab, it used to take half a day to instrument a car, and another half day to strip it after the test. To speed up the process dramatically, Visteon uses a patented non-contact laser measurement process – it now just takes 20 minutes beginning to end, and companies can now perform a full NVH analysis on 30-35 vehicles a week. Before, that much work couldn’t be done in a month, and so testing was done with a statistically less representative sample. On-site testing also lowers the risk of damage done to a vehicle by driving it to a test site, and permits testing to take place with parameters that exceed legal limits on public roads.
More than just testing -analysis
The Visteon team provides more than just a simple test – they provide a solution. The process usually begins with a complete multichannel test, followed by one of two paths: either NVH analysis or powertrain dynamics analysis. These reveal dynamic factors that are integral to the design validation process and functional characteristics of the vehicle. NVH testing identifies and locates the root cause of vibration or interior sound problems and gives engineers an insight into how to correct the situation. Driveline analysis detects driveline roughness or interior sound boom – root causes of driver discomfort. The Visteon algorithms calculate the imbalance and suggest corrections so that engineers can eliminate the problem.
LMS onboard
LMS CADA-X SMON and FMON are two of the tools that enable Visteon to do their testing on the Dyno lab: they even integrate the non-contact type laser measurements that are key to the speed and success of the mobile lab. The jobs that are performed in the mobile lab are often based on a set of routine tests. For instance, info on interior cabin noise is collected on every run as part of a standard run of tests. LMS CADA-X tools were made to capture and standardize testing procedures designed by expert users. Though the Visteon mobile labs are staffed with specialized engineers, the data can ordinarily be gathered by trained technicians. Frank says about his crew, "They give objective data from which developers can work on specific issues. Clients want that, not subjective, after-a-drive opinion, as was often the case in the past."
Generally a 2-4 person engineering crew executes the testing and delivers interpretation of the results on the spot: what the problem is and where it’s coming from. The LMS reporting tools that empower the visualization of acoustic data make this almost instantaneous delivery possible. "Our mission is to collect the info and compile a report – the client is responsible for using the info," states Frank. "With the exception of our own Visteon quality programs, we rarely do prescriptive reporting, just diagnostics."
Back at base, Visteon’s permanent NVH lab is fully equipped with LMS CADA-X tools such as Modal and Transfer Path Analysis, meaning that data measured in the portable dyno can be extensively processed in the lab afterwards.
