For more than 65 years, Link Engineering Company has focused on the design and manufacture of test systems for the automotive, aerospace, railway and general industries. Its systems are used by major vehicle and component manufacturers throughout the world. Link’s experience includes the development and manufacture of a wide range of NVH (Noise, Vibration and Harshness) test systems. Brüel & Kjær’s PULSE™ Multi-analyzer is Link’s preferred NVH analyzer platform – some 20 systems have been delivered during the last 18 months.
The Automotive Industry
Founded in 1935, Link has, throughout its history, focused on the design and manufacture of test systems for the automotive industry. Based in Plymouth, Michigan, USA, the company employs approximately 250 people.
Brake NVH analysis using a Link Dynamometer
Link designs and manufactures a full range of test systems for laboratory, test-track and on-road vehicle evaluation including, for example:
Brake and transmission dynamometers
Vehicle data acquisition systems and transducers
Vehicle and aircraft chassis dynamometers
Material characterisation systems
Link is a market leader and supplies dynamometers and NVH test systems to the world’s major automotive manufacturers, to producers of automotive components, and to suppliers of automotive raw materials. To date, Link has delivered more than 100 vehicle data acquisition systems throughout the world.
Data Acquisition and Analysis System
A complete state-of-the-art Link Engineering dynamometer control and data acquisition system is a key component in all Link dynamometers. Each dynamometer has its own dedicated PULSE Multi-analyzer. This PC-based noise and vibration measurement system is capable of data acquisition, measurement, post-processing, documentation and analysis with simultaneous measurement of exponential, linear, peak and averaged spectra. The system provides software for noise analysis, time data recording and order tracking.
The PULSE software is controlled by Link’s ProLink software package running under Windows® 2000. ProLink provides the intuitive graphical user interface and maximises speed and flexibility in the capture and retention of all relevant test data. Monitored parameters include speed, torque, up to eight temperatures, relative humidity, applied pressure and many other parameters.
James K. Thompson, PhD, PE, is Link’s NVH Sales and Marketing Executive Director. Jim has worked at Link for five years – he is an NVH expert.
Jim says, “Our test systems are used in R & D applications all over the world and, in addition to testing vehicle brakes, clutches and transmissions, we are expanding our solutions to include a wide range of other automotive components, such as steering assemblies, alternators, starter motors, etc.”.
Jim continues, “Our users are not generally NVH experts and so we aim to make our test systems as automated as possible. A really great development is TEDS (Transducer Electronic Data Sheet) equipped transducers. It’s a major plus for customers with little or no NVH experience. TEDS transducers reduce the setup time and there are far less errors because the transducer sensitivity is entered into the system automatically”.
James K. Thompson, PhD, PE, is Link’s NVH Sales and Marketing Executive Director
“There is an increasing trend towards in-vehicle testing for troubleshooting applications”, says Jim. Link Engineering has developed a new vehicle measurement system that provides full NVH measurement capabilities along with the ability to capture up to 72 channels of non-NVH data. The Link Model 3501 Modular Vehicle Data Acquisition System employs a modular approach. It’s the foundation for vehicle NVH cause and effect analysis and is a compact and highly integrated unit. The standard NVH module is 6/1-channel PULSE Multi-analyzer.
In-vehicle testing – Link’s 3501 system installed in a truck cab
With a range of 30 dynamometers and some 120,000 square feet (about 11,150 square metres) of laboratory space, the Link Testing Laboratory in Detroit provides testing facilities to third-party customers. There are few such facilities available for contract use and independent studies. The services offered include:
Product NVH performance evaluations from components to complex systems – from large scale fleet or customer satisfaction surveys to detailed “cutting-edge” test and analysis
Root cause investigations to identify sources mechanisms, transmission paths, and subjective response
Vehicle interior and exterior noise and vibration measurements, including temperature and strain measurements
A new Link Testing Laboratory will soon be commissioned near Frankfurt, Germany.
A New Link Dynamometer – this one is destined for Link’s new testing laboratory in Germany
A Preferred Supplier
Jim explains, “In the past we had a number of options concerning analyzers. But we decided to work with Brüel & Kjær and they are our preferred supplier, not only for analyzers but also for transducers and calibration equipment. Brüel & Kjær’s name stands for outstanding quality, reliability and accuracy. PULSE is a PC-based solution and this is the way we wanted to go. The decision has proved to be correct and we get excellent back-up, service and support from their local office in Livonia, Detroit”.
Jim continues, “We also use a 6/1-channel PULSE system in our own test lab. Together with transducers, it’s extensively used to check the performance of our test systems before delivery to a customer, and for general investigative work and troubleshooting”.
Twenty-plus PULSE Systems
Since the cooperation with Brüel & Kjær started in the beginning of 2001, Link has ordered more than twenty PULSE systems. Jim concludes, “This is positive proof of the success of both our companies and, of course, our customers favour PULSE as the standard analyzer installed in our NVH test systems. They appreciate that they get the best available analyzer with all the PULSE functionality and capabilities for a wide range of NVH test applications.”
Quote: “…our preferred supplier, not only for analyzers but also for transducers and calibration equipment”