Rethinking IC Engines

By Thilmany, Jean

AN AUSTRALIAN COMPANY recently took an idea for an internal combustion engine from idea to prototype in about half a year. Bradley Howell-Smith designed and patented the engine in the 1990s. As described in the U.S. patent’s abstract, the engine “comprises two counter rotating multilobate cams, which are acted upon by a pair of diametrically opposed pistons which are rigidly interlinked by connecting rods. Differential gearing is provided to time the counter rotation of the cams.”

In July 2006, Howell-Smith conceived of a variation on his original design. Called the X4, the new design would reduce by half the size and weight of most engines of similar capacity. The challenge now was to take the idea from concept to working prototype in just seven months.

“We had a company coming to see us in February 2007,” Howell- Smith said. “They weren’t expecting to see a working model by that time, but we wanted to impress them with what we could do.”

By this time, he’d formed Revetec Holdings Ltd. of Gold Coast, Queensland, Australia, to bring his engines to market. The company consists of two people. Howell-Smith does the design work and Paul Moitzi, a machinist, builds the prototype engines. They both use the computer-aided design software Solid Edge from Siemens PLM Software of Piano, Texas.

Although he had been contracting out analysis work, when HowellSmith started work on the X4 engine, the current release of Solid Edge included Femap Express structural analysis software. He decided to test the linked CAD and analysis system.

Because Howell-Smith did the analysis work himself, the design and analysis process that formerly took him two weeks was done in a halfhour. In-house analysis also saved him the $1,000 to $2,000 fee he paid the analysis contractor, he said.

Howell-Smith started designing the X4 on July 10, 2006, and finished modeling the entire engine before the end of the year. The prototype is now built and is undergoing testing and tuning.

Revetec designer Bradley HoweH-Smith designed, analyzed, and built his patented Internal combustion engine, called the X4, In just seven months with the help of his linked CAD and analysis software package.

Copyright American Society of Mechanical Engineers Jun 2008

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