By the year 2020 the first cylinder housings manufactured from polymer composite materials will be introduced into passenger car and motorcycle engines, replacing the aluminium components currently in use, predicts SBHPP High Performance Plastics, a business unit of Sumitomo Bakelite.
SBHPP's research has proven that glass fibre reinforced phenolic cylinder housings manufactured using the injection moulding process deliver the same performance as die cast aluminium componentsbut offer a significant reduction in weight, lower engine noise and reduced heat radiation. Weight reduction isa primary objective for automotive manufacturers under increasing pressure to improve fuel economy and reduceemissions. In addition, life cycle assessments demonstrate that the environmental impact of phenolic composite components over their entire lifetime is lower than that of aluminium alternatives.
"In 3-5 years' time composite cylinder housings will be a reality," says Hendrik De Keyser, Marketing and Technology Officer at SBHPP in Gent. "We believe this composites technology will first be adopted in small engines of up to 1.6 litres. Implementation in higher performance and higher displacement engines will follow."
As the market leader in phenolic moulding compounds, SBHPP has been developing thermoset composite parts for the automotive industry for more than 20 years.At its operations throughout North America, Europe, Japan and China, the business possesses all the development equipment and expertise necessary, including simulation and testing facilities, recycling capabilityand technical centres where prototypes can be produced for customers. Recent work has involved a cooperation with the Fraunhofer Project Group - New Drive Systems, in Karlsruhe, Germany, during which SBHPP manufactured a proof of concept composite cylinder casingfor a single-cylinder 650cc engine. A 55% glass fibre reinforced phenolic was usedin combination with integrated metal inserts and a metal cylinder liner.The optimised injection moulding process developedresulted in a cycle time of 90 seconds.
Compared with the aluminium part the composite casingdelivers a weight reduction of up to 20%, and manufacturing costs are approximately 10% lower for a production run of up to 30,000 parts/year. For higher production volumes thiscost reduction becomes even more significant.
Improved noise, vibration and harshness (NVH) behaviour was found to be a further notable benefit of composites. Acoustic tests confirmed a significant noise reduction for the composite cylinder casing compared with the aluminium reference part. In addition, thermal tests verified reduced heat radiation from the composite part to the surrounding environment.Thermosensors mounted on the exhaust, drive and inlet side of the composite partall settled at a significantly lower temperature than the sensors on the aluminium component.
SBHPP is now planning to work with engine suppliers andautomotive OEMs to take this conceptto market.It also plans to build on the success of this research by developing a more complex multi-cylinder composite-based engine, with the ultimate aim of introducing an all-composite engine. This is envisioned in the virtual engine concept, a small, scalable engine architecture with two, three or four cylinders which uses SBHPPcompounds and composite materials. This engine is designed for use as primary engine for passenger cars or motorcycles or as a range extender for electric vehicles.
