Gas exchange processes of a small HCCI free piston engine – A computational study

Sofianopoulos, Aimilios; Zhou, Yingcong; Lawler, Benjamin; Mamalis, Sotirios

doi:10.1016/j.applthermaleng.2017.08.089

Cited by 26 publications

(22 citation statements)

References 51 publications

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“…The geometric schematic of the CFD model of a loop-scavenged, single-piston FPE. 56 increased piston acceleration around BDC. 59 The loop scavenging approach has also been used by other researchers such as Li et al 28 and Zulkifli et al, 60 who presented similar findings.…”

Section: Loop Scavengingmentioning

confidence: 94%

“…The study showed that a trapping efficiency of greater than 98% can be achieved through targeted design of the ports and the combustion chamber. 56 Mao et al used CFD modeling to simulate the gas exchange process of a dual-piston engine with three scavenge ports, one exhaust port, and a large plenum to supply air to the combustion chamber at a constant pressure, and showed that thorough purging of the cylinder was achieved. Short-circuiting losses were eliminated by direct fuel injection.…”

Section: Loop Scavengingmentioning

confidence: 99%

“…[57][58][59] However, if a large amount of internal residuals are desired, loop scavenging can be designed to minimize trapping losses, as shown in Figure 11. 56 Goto and colleagues 20,21 presented a uniflowscavenged DI, FPE and showed the potential to achieve premixed charge compression ignition (PCCI) with high thermal efficiency. Haag et al introduced a uniflowscavenged, DI, free-piston concept as a precursor to the design of their opposed-piston, range extender.…”

Section: Uniflow Scavengingmentioning

confidence: 99%

“…Trapping efficiency versus scavenging efficiency for loop, hybrid-loop, and uniflow scavenging. 56 variable stroke and compression ratio, it is much more challenging to obtain useful experimental data in an FPE compared to a crank-slider engine. Therefore, the majority of FPE combustion studies have been conducted numerically, sometimes without experimental validation.…”

Section: Combustion Processesmentioning

confidence: 99%

“…The results also showed that 38% net indicated efficiency could be achieved by minimizing trapping losses. 56 Van Blarigan et al at SNL were the first group to study HCCI FPE characteristics. They showed that FPEs can reach the target compression ratio faster than crank-slider engines for the same maximum piston velocity, which can lead to higher pressure at TDC and facilitate HCCI combustion.…”

Section: Ltcmentioning

confidence: 99%

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Advanced combustion free-piston engines: A comprehensive review

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A reciprocating engine without a crank-slider mechanism is called a free-piston engine. If the piston is directly connected to a linear alternator, it is called a free-piston linear alternator. Free-piston engines and free-piston linear alternators have the potential to offer solutions for future hybrid electric vehicles and stationary power generation, by enabling direct conversion of mechanical energy to electricity. They benefit from reduced friction losses compared to conventional engines and can have variable compression ratio, which enables combustion control and optimization. Their widespread application has been limited by the necessity for high-speed control strategies. However, their operating characteristics can provide high efficiency, especially when used with low temperature combustion strategies. Low temperature combustion combines the high thermal efficiency of diesel engines, with the low soot emissions of spark-ignition engines, and low NO x emissions because of low burned gas temperatures. This article provides a comprehensive review of free-piston engine technology, with a focus on advanced combustion processes and their potential for use in future powertrain systems.

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