The premise of a split-cycle engine is that segregating the intake and compression strokes in one cylinder and the combustion and expansion strokes in another, coupled cylinder, provides a thermodynamic advantage enabling a more efficient engine. Most current split-cycle designs, however, use a long gas crossover passage or intermediate chamber to connect the cylinder pair, which make these engines deviate significantly from conventional 4-stroke thermodynamics.

Over the past year, Tour Engine has conceived, patented, developed and prototyped a new crossover valve mechanism. The Tour engine with the new technology—which can be realized in an inline configuration—is currently being tested, and is initially showing good functionality, says Tour Engine CEO Dr. Oded Tour.

Simulated GT-Power predicted performance of two configurations of the Tour engine (equal compression/expansion and over-expansion). Source: Tour Engine. Click to enlarge.

Over the past 4 years, the company has been the recipient of 4 grants: 3 from the Israeli Ministry of National Infrastructures, Energy and Water Resources and one from California Energy Commission’s Energy Innovations Small Grant (EISG). (Earlier post.) Currently Tour has two proposals that are pending: one with the US DOE EERE and the other in Israel.

The company may also respond to a coming ARPA-E solicitation, potentially in partnership with one or two prominent US academic engine research centers. In addition, the company is planning in the near future to renew discussions with selective OEMs, focusing on the merits of the new crossover valve mechanism and exploring joint development opportunities, Tour said.