05.2021.196.206

A Theoretical Study of A Variable Compression Ratio Engine with Using Piston of Variable Height

Author(s):

Sarah H. Ali, Haider J. Abid, Mohsen H. Fagr

Affiliation(s):

Mechanical Engineering Department, University of Thi-Qar, Iraq.

Corresponding Author Email: haider-jabaur-abid@utq.edu.iq

This is an open access journal distributed under the Creative Commons Attribution License CC BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

The engines with variable compression ratio have a significant effect on increasing the power of engine and decreasing the fuel consumption and pollutions. The modified engine was designed to produce the new technology for variable compression ratio engine using variable piston’s height. Where the piston consists of two parts, (upper part and lower part), the height of piston varies by press hydraulic between these parts via pipe within cylinder head. The MATLAB program was used to determine the thermal characteristic for the studied engines (Otto Cycle Engine, Pre-Variable Compression Ratio Engine, Instantaneous Variable Compression Ratio Engine, Miller Cycle Engine with late valve close, Pre-Variable Compression Ratio Miller Cycle Engine with late valve close and Instantaneous Variable Compression Ratio Miller Cycle Engine with late valve close) with/without turbocharger. The results showed the Instantaneous Variable Compression Ratio Engine is the highest power when used without turbocharger. The Instantaneous Variable Compression Ratio Miller Cycle Engine with late valve close has the highest power when it used with turbocharger in maximum limit of compression ratio (1:12). Thus, the modified engine can be used in new technology of variable compression ratio engines.