Trelleborg Automotive, a leading provider of comfort solutions to the automotive industry, has announced that it has developed an innovative damping plate that allows PSA Peugeot Citroën to reduce noise and vibration caused by diesel-engine knocking.
Trelleborg Automotive has developed an innovative damping plate that allows reduction of noise and vibration caused by diesel-engine knocking.Having been approached by PSA to find a solution to the problem of diesel-engine noise, Trelleborg Automotive used its vast NVH experience to produce a specially-cut shear plate, engineered using the company’s Duru-LAM material. Resistant to both heat and oil, Duru-LAM is a proven material for damping sound and vibrations in internal engine applications and in the shear plate design, it comprises a layer of rubber sandwiched between two layers of steel. The shear plate is then positioned according to the packaging requirements of different core engine designs and can be used in gasoline, as well as diesel variants.
Commenting on the introduction of the shear plate, Arvid Norberg, R&D NVH Manager at Trelleborg Automotive, says, “The conventional solution to reduce vibration is to increase engine block stiffness, but in many cases this only shifts the noise to higher frequencies. The introduction of the shear plate enables us to reduce vibration and noise levels, resulting in considerably improved sound quality.”
“Duru-LAM uses rubber in the middle layer, vulcanised together with two steel layers. This makes it much tougher than conventional sandwich materials, where the polymer simply can’t handle the oil. Duru-LAM is not only very durable, but also boasts a high shear strength”, he adds.
Since receiving shear plate prototypes from Trelleborg Automotive, PSA Peugeot Citroën has undertaken rigorous acoustic research and simulation testing of the part and has developed a technique which enables ranking of engine sound quality.
“We have been immensely impressed by the results of the shear plate testing, such that one of our NVH senior experts has already heralded the concept a revolution for reducing diesel engine noise”, explains Léon Gavric, Senior Acoustics Expert and Head of PSA Peugeot Citroën’s Powertrain NVH Department. “We achieved considerable improvement in sound quality with Trelleborg’s shear plates and found that severe noise quality would improve to acceptable or very good.
“The shear plate filters out unwanted vibrations and knocking noise, but the real gain is that by reducing noise and vibration issues, we can tune the combustion to reduce emissions, pollutants and fuel consumption. As a result, it makes designing higher-performance eco-friendly engines a reality”, adds Gavric.
Trelleborg Automotive also expects its shear plate concept to deliver additional cost-savings, by reducing the need for other, more expensive and heavier damping solutions. The company is currently undertaking further damping tests with its Duru-LAM material, using FEM tools to determine thickness measurements and shear plate tuning requirements of different engine types.
In addition, Trelleborg Automotive’s shear plate concept is expected to greatly assist manufacturers upon the introduction of new European emission standards, Euro 5 and Euro 6. While improved combustion efficiency is regarded as the quickest and most cost-effective method to reach the requirements of the new standards, this invariably induces vibrations which are transmitted to other engine parts – thereby increasing overall noise levels significantly.
“With new European emission standards just around the corner, we expect our shear plate concept to offer manufacturers a viable means of meeting requirements while continually reducing vibration noise in both diesel and gasoline engines”, concludes Norberg.