Continuously Variable Displacement (CVD) Engine Concept Validation

The majority of engines in the world operate at low load duty cycles, a prime example being the automobile engine. The majority of fuel is burned far from the best fuel consumption operating point. The method of control of the engine has a significant impact on the losses at part load. Control by throttling 1) creates pumping work loss, 1) reduces the peak pressure for the exhaust gas to expand from (i.e. reduces the compression ratio), and 3) keeps the engine friction near the full load friction. ESI, Inc. has designed and patented a novel crank mechanism that provides displacement control by reducing the piston stroke and the combustion volume in concert. A Cummins Engine funded GT-Power simulation has shown a 30% improvement in fuel consumption (lower CO2) over the FTP cycle compared to a baseline gasoline engine. A number of major engine OEMs have concurred with the fuel economy gains but require validation of the mechanism before formally considering the engine for production. Friction, bearing capacity/life, balance, and durability potential are the key points to be satisfied to move this design forward. Project Objectives and Tasks Although there has been a significant amount of analysis and simulation of the engine drive system, a full multi-body dynamic analysis has not been done. Phase I will consist of a full multi-body dynamic analysis as well as finite element stress analysis on all structural members. These analyses will lay a solid foundation for moving the project into Phase II. Phase II would be to build a test prototype and do basic dyno testing of the design. The CVD engine reduces pumping losses, improves the Pressure-Volume diagram, reduces friction and waste exhaust energy as does “boosted, downsized, downsped, dilute” gas engines with variable valve timing and cylinder deactivation. However, it does all of that with just one mechanism and achieves a more complete reduction of losses. Thus it is anticipated to be a major cost reduction at a given CO2 level. Commercial Applications This technology can have a major impact on reducing global warming and reducing consumption of fossil fuels by improving the efficiency of internal combustion engines that don’t run at full power all of the time. It is applicable to automobiles, trucks, gen-sets, offhighway engines, motorcycle and motor scooter engines, and light industrial engines. The global market of these engines was over 100,000,000 in 2015. Key Words Variable Stroke engine, Variable Compression Ratio, Improved Engine Efficiency