Pasadena-based Stirling Cycles, a company developing Stirling engines, technology used as an alternative to internal combustion, has been acquired by Washington-based Infinia. Financial terms of the deal were not disclosed. Infinia said today that the acquisition came as part of a venture funding round from Kholsa Ventures, vulcan Capital, EQUUS Total Return, and Idealab. Idealab had been incubating Stirling Cycles, which was working on development of Stirling engine based products and technologies.