Alan Taub: GM pushing on split-cycle engine technology in the lab; looking for low-load efficiency and packaging
Noting that split-cycle engine technology “really looks promising”, GM Vice President of Global Research and Development Dr. Alan Taub said that the company is putting on a “major thrust” in its R&D laboratory to see if it can get split-cycle technology “moving”. He made the remarks during the introductory plenary session today at the DOE’s 17th Directions in Engine-Efficiency and Emissions Research (DEER) Conference in Detroit.
Taub noted that improved technology is enabling engine makers to go back to options to improve engine efficiency that have been talked about for decades, but were not then possible to realize. One of those potential high-efficiency options is the split-cycle engine, which separates the compression and expansion components of the combustion cycle into discrete cylinders.
Today the split cycle is still in the laboratory, together with some collaboration outside of GM. The promise of dramatically increased efficiency is what we are looking for. There are two prongs to this effort. Can we get the peak efficiency north of 50%, and more importantly, can we really move up the efficiency at low loads, which is where that technology is really challenged? And how tight can we get the package and the weight and the incremental cost?
The driving force is clear, we can see dramatic improvements in efficiency by going to the DCDE [discrete compression discrete expansion] architecture. It’s definitely something we need to explore further.—Alan Taub
In September, the Scuderi Group released findings from a computer simulation study measuring the performance of the Scuderi split-cycle engine modeled against the European class of “high economy” vehicles. The data showed that a turbocharged/air-hybridized Scuderi Engine can achieve at least 64 mpg US (3.7 liters per 100 km) while emitting 85 g CO2/km. (Earlier post.)
Another split-cycle start-up, Tour Engine, reports that a simulation of its opposed-cylinder design run by an independent consultant—and verified by a major OEM—suggests that a feasible configuration of the TourEngine could achieve about 56% brake thermal efficiency (BTE). (Related post.)
Taub also noted that GM was pushing ahead with its development of HCCI (homogeneous charge compression ignition) engines (earlier post), and would be exploring application in downsized turbocharged engines such as the new 1.4L Ecotec (earlier post).