Increased Power Density via Variable Compression/Displacement And Turbocharging Using The Alvar-Cycle Engine 981027
This paper presents the analysis and design of a variable compression-ratio and displacement engine concept - the Alvar Cycle using a four-stroke engine-performance simulation. The Alvar-Cycle engine uses secondary pistons which reciprocate in auxiliary chambers housed in the cylinder head, at adjustable phase-angle differences from the primary pistons. The phase difference provides both the variable total engine displacement and compression ratio. Results indicate that the Alvar engine can operate at higher power density via a combination of higher intake boost and lower compression ratio to avoid knock at high loads, and capture the better thermal efficiency at higher compression ratios at part loads.
Citation: Wong, V., Stewart, M., Lundholm, G., and Hoglund, A., "Increased Power Density via Variable Compression/Displacement And Turbocharging Using The Alvar-Cycle Engine," SAE Technical Paper 981027, 1998, https://doi.org/10.4271/981027. Download Citation
V. W. Wong, M. Stewart, G. Lundholm, A. Hoglund
Massachusetts Institute of Technology
International Congress & Exposition
1998 Variable Valve Actuation and Power Boost-SP-1346, SAE 1998 Transactions - Journal of Engines-V107-3