Analysis of a Stratified Charging Concept for High-Performance Two-Stroke Engines

Zahn, W.; Rosskamp, Heiko; Raffenberg, Michael; Klimmek, A.

doi:10.4271/2000-01-0900

Cited by 7 publications

(3 citation statements)

References 2 publications

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“…Previous studies showed the reed valve applications in two-stroke engines such as admission valve to the combustion chamber [5], air entering into the transfer ports to support the scavenging process of the exhaust gases before the fresh mixture enters in the combustion cylinder [6,7], and assisting the turbocharging [8]. Other application areas include reducing the engine emissions with a secondary air injection (SAI) [9][10][11], increasing the charge stratification [12], and improving the exhaust gas recirculation (EGR) system [13,14].…”

Section: Double Compression Expansion Enginementioning

confidence: 99%

“…The reed valves are a device similar to the most recognized check valves allowing the fluid to flow only in a single direction. This kind of valve is widely used in certain applications such as reciprocating compressors, rotary type combustion engines, and two-stroke engines-motorcycles, remotely piloted vehicles [31], or machines as brush cutters, blowers, hedge trimmers, and chain saws [12]. The basic components of a reed valve are shown in Figure 4.…”

Section: Reed Valvementioning

confidence: 99%

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Reed Valve Evaluation and Selection for the Compressor Cylinder in Double Compression Expansion Engine (DCEE) Concept

Cabezas

Goyal

Andersson

et al. 2021

SAE Technical Paper Series

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This paper shows the potential benefits of implementing four configurations of reed valves at the inlet of the two-stroke compressor used in the double compression expansion engine (DCEE) concept or 8-stroke engines over the conventional poppet valves used in 4-stroke internal combustion engines. To model the reed and poppet valve configurations, the discharge coefficient was estimated from RANS computational fluid dynamics simulations using ANSYS Fluent 2020 R1, with a pressure difference up to 0.099 bar. The calculated discharge coefficients for each case were then fed in a zero-one dimension model using GT-Power to understand the valve performance i.e. the volumetric efficiency of the compressor cylinder and the mean indicated pressure during the compression process at 1200 rpm. The results showed that for reed valve configurations, the discharge coefficient and mass flow rate were higher, the pressure drop was lower and the response with negative pressure difference was faster compared to poppet valves. In addition, all the reed valve cases showed improvement in volumetric efficiency and a drop in mean effective pressure than poppet valves. In particular, the optimum reed valve geometry in the present study resulted in a volumetric efficiency improvement of 7.2 percentage points and a mean effective pressure reduction of 3.2 percentage points compared to conventional poppet valves.

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Section: Double Compression Expansion Enginementioning

confidence: 99%

Section: Reed Valvementioning

confidence: 99%

Reed Valve Evaluation and Selection for the Compressor Cylinder in Double Compression Expansion Engine (DCEE) Concept

Cabezas

Goyal

Andersson

et al. 2021

SAE Technical Paper Series

View full text Add to dashboard Cite

show abstract

“…After these first numerical studies, a lot of works appeared in the nineties and in recent years. The number of CFD codes has also increased noticeably, appearing studies using KIVA (Epstein et al, 1991;Amsden et al, 1992), STAR-CD (Raghunathan & Kenny, 1997;Yu et al 1997;Zahn et al, 2000;Hariharan et al, 2009), FIRE (Hori et al, 1995;Laimböck et al, 1998) Fluent (Pitta & Kuderu, 2008;Lamas-Galdo et al, 2011), CFX (Albanesi et al, 2009), etc. …”

Section: The Scavenging Processmentioning

confidence: 99%