Reduction of Emissions through Increased Temperature Performance and Lower OEM Costs

Automotive original equipment manufacturers (OEMs) have to work in close cooperation with suppliers to achieve reduced costs and improved performance in order to meet stringent emissions standards, satisfy increased engine temperature demands, and tackle low-cost competitors. This article discusses the solution provided by Dow Corning to address a problem faced by a North American automotive OEM.

The Problem

The North American automotive OEM wanted to minimize costs of light duty truck engines with particular focus on satisfying rigorous emissions standards. The company came across an innovative solution from Thermopol Inc., a manufacturer of specialty hoses, which helped the OEM to achieve its objectives through the elimination of an engine component.

However, the OEM faced a new set of problems in the form of rising engine-operating temperature because of the revised engine design. This prompted Thermopol to approach its technology partner, Dow Corning, to create an advanced material capable of tolerating the increased temperature specifications and other extreme engine conditions. The actual challenge confronted by Dow Corning was the requirement to develop the product in half the time acceptable for the standard product development.

In addition, turbocharger hoses need to be flexible enough to tolerate aggressive conditions of automotive oils, fuels, and gases, lower vibration and noise, and handle turbocharger placements that vary for different models. For performance improvement, an entire hose assembly capable of withstanding continuous operation at temperatures 20-30ºC above the previous value.

Dow Corning’s Solution

Dow Corning was asked to determine the suitable silicone material for a fluoro-elastomer hose liner to deliver continuous operation at 235ºC. Besides Dow Corning’s high-performance material, Thermopol’s hose needed significant engineering to enable the entire hose assembly to withstand the elevated operating temperature.

Dow Corning and Thermopol jointly analyzed the Dow Corning technology platform to identify the suitable fluorosilicone product that exhibit superior oil resistance, good fuel resistance, and low permeation over a broad range of temperatures. What they had identified were two multi-layered fluorosilicone (FSR) and high-consistency rubber (HCR) hose liner materials. Further analysis of these two options concluded the selection of the Silastic^® brand FSR formulation, which was tailored for the OEM’s hose liners to achieve superior performance at elevated temperatures.

Since Dow Corning has a long-time relationship with Thermopol, it had clear idea about the processing needs of the specialty hose manufacturer. The result was the quick production of the custom FSR solution, which enabled Thermopol to realize an economical production process and deliver an improved product to the OEM.

The Oil-Resistant Turbocharger Hose Liner

The proactive response of Thermopol and Dow Corning enabled the oil-resistant turbocharger hose liner (Figure 1) that can operate continuously at 235-240ºC. The liner is the result of the integration of the material performance design and hose construction design and the testing of a range of Silastic brand FSR products. All these FSR products failed to meet the Thermopol’s production specifications and the hose liner performance specifications.

Figure 1. Hose developed by Thermopol with Silastic brand silicone rubber from Dow Corning.

Hence, Dow Corning developed a tailored Silastic brand FSR formulation using its FSR technology. The resultant Silastic brand FSRs can be calendared or molded for applications demanding resistance over a wide range of temperatures as well as resistance to oils and fuels.

They are suitable for most aerospace and automotive applications involving extreme conditions, such as fuel line pulsator seals, engine gaskets, natural vacuum leak protection control diaphragms, vapor recovery management system seals, fuel-resistant hydraulic and electrical clamp blocks, exhaust gas recalculating diaphragms, electrical connector inserts, fuel line quick-connect seals and air pump valves.

Conclusion

The high-performance, cost-effective solution was delivered on a very tight schedule through substantial reduction in the time allowed for the standard material development and qualification cycle. The innovative solution enabled the OEM to remove the targeted engine, thereby achieving significant savings in costs and emissions.

Automotive design continues to evolve to meet increasing demand for high performance in extreme conditions. Dow Corning meets the requirements of its automotive customers through close cooperation, thereby helping the industry to achieve reduced cost, weight, and emissions, while improved fuel efficiency.

This information has been sourced, reviewed and adapted from materials provided by Dow Corning Automotive.

For more information on this source, please visit Dow Corning Automotive.