Study of the performance of a natural gas HCCI engine coupled with an Organic Rankine Cycle

Details

Supervisors

Jeanmart, Hervé

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil mécanicien

Abstract

Homogeneous Charge Compression Ignition (HCCI) combustion is a promising way to combine both the advantages of the traditional Spark Ignition (SI) and Compression Ignition (CI) engines. Similarly to SI engines, a homogeneous charge is used, providing low NOx formation, and is compressed to auto-ignition as in diesel engines, resulting in a high efficiency and reduced CO2 emission. The objective of this thesis is to study the performance of a stationary HCCI engine running on natural gas. Particularly, three methods have been reviewed in order to achieve higher power: turbocharging, exhaust gas recirculation (EGR) and coupling with an Organic Rankine Cycle (ORC). Towards that goal, a test bench was implemented and used to experimentally study the influence of the intake conditions on the engine performance. Experiments were conducted on a four-cylinder HCCI engine operating with natural gas. Furthermore, a turbocharger and an EGR system were added to the test bench in order to analyse their impact on the engine power. An HCCI 0-Dimensional model was developed and used together with experimental results to evaluate the optimum performance of the HCCI engine. A mathematical model was implemented for the theoretical study of the ORC in order to estimate the final performance of the HCCI-ORC system. Results showed that when coupling with the Organic Rankine Cycle, the whole system could achieve an overall efficiency of 50.2%, which makes it quite competitive with the SOFC-MGT system and its 55% efficiency. Despite some assumptions made in the frame of this thesis, the HCCI-ORC system seems to be a promising technology in stationary power generation.