Experimental Analysis for the Influence of Ignition Time on Combustion Characteristics of a Free Piston Engine Linear Generator

Abstract

Free Piston Engine Linear Generator (FPELG) is a modern engine and promising power generation engine. It has many advantages compared to conventional engines such as less friction, few numbers of parts, and high thermal efficiency. The cycle-to-cycle variation one of the big challenges of the FPELG because it is influence on the stability and output power of the engine. Therefore, in this study, the effect of ignition time on combustion characteristics is investigated. The single-cylinder FPELG with spark ignition (SI) combustion type by using compressed natural gas (CNG) fuel type was set to run. LabVIEW is used to run the engine and control of input parameters. All experimental data have been collected and processed based on LabVIEW and Macro tool. The analysis results of the experimental based on ignition time show that the in-cylinder pressure with double peak shape was produced when the ignition delay after Top Dead Centre (TDC). On the other hand, the in-cylinder pressure and output power with ignition before TDC is higher in approximately (33.8%, and 17.8% respectively) compared to the in-cylinder pressure with ignition after TDC. Though investigate the influence of ignition time on the combustion characteristics but with further study and investigation for such as the combustion during expansion, exhaust gas temperature, and emission under various ignition time could be achieved in our future work.

Combustion Characteristics of a Free Piston Engine Linear Generator using Various Fuel Injection Durations

“…Thus, this type of FPELG requires controlling some parameters, and a highly accurate control strategy requires too 6,7,15) . The researchers in previous studies focused on some parameters such as ignition timing and piston motion control of FPELG 12,16,17,18,19) . The forces generated by FPELG were classified into the forces that come from in-cylinder pressure for each side of FPE.…”

“…However, the piston motion of FPELG has different characteristics compared to the conventional engine. Because there is no crankshaft for FPELG the differences can be described by the association between the engine performance and the injection position, ignition timing, and injection timing 19) . Moreover, the crank angle value in conventional engines was used as an injection timing signal value.…”

Simulation investigates on operation characteristics of free piston internal combustion generator

“…10 Raheem et al studied parameters affecting FPEG performance through experiments, and the results showed that piston motion control is the key issue to affect FPEG stability. 11 ZHANG et al studied the influence of structural parameters on generator performance by simulation, and the results showed that cylinder diameter ratio and stroke have great influences on thermal efficiency, fuel economy and ignition position. 12 Feng et al studied the influence of key parameters on the startup process, proposed a method for comprehensive optimization of design and operation parameters, and investigated the impact of key design parameters (like the mover assembly mass and stroke ratio) on the system operation characteristics.…”