Diesel Combustion Phenomena as Studied in Free Piston Gasifiers

Fleming, James D.; Bayer, Robert

doi:10.4271/630449

Cited by 5 publications

(7 citation statements)

References 8 publications

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“…The trend of an increased heat release rate in the pre-mixed phase is consistent with the experimental findings of Achten et al [7], Tikkanen et al [8] and Fleming and Bayer [14], discussed above. It should be noted that, as the current engine is turbocharged, the ignition delay and the fraction of fuel burnt in the pre-mixed phase is lower than what would be expected in a naturally aspirated engine.…”

Section: Combustion Progresssupporting

confidence: 91%

“…Discussing the freepiston engine multi-fuel possibilities, Flynn [13] described the successful operation of a free-piston engine on a range of fuels including gasoline, diesel fuel, crude oil and even vegetable and animal oils, and stated that "It seems that these engines do not care whether they get fuel with octane or cetane numbers". Fleming and Bayer [14] reported abnormal combustion leading to mechanical problems in the free-piston engine, and stated that thermodynamic models had to be modified to fit free-piston engine data due to long ignition delays and high heat release rates. The authors described how the performance was improved with changes in the injection system, and further stated that when recreating the conditions under which the free-piston engine was successfully operated in a conventional engine, this engine would not run.…”

Section: Free-piston Engine Combustionmentioning

confidence: 99%

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A computational study of free-piston diesel engine combustion

2009

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This paper investigates the in-cylinder gas motion, combustion process and nitrogen oxide formation in a free-piston diesel engine and compares the results to those of a conventional engine, using a computational fluid dynamics engine model. Enhanced radial gas flow (squish and reverse squish) around top dead centre is found for the free-piston engine compared to a conventional engine, however it is found that this has only minor influence on the combustion process. A higher heat release rate from the pre-mixed combustion phase due to an increased ignition delay was found, along with potential reductions in nitrogen oxides emissions formation for the free-piston engine.

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Section: Combustion Progresssupporting

confidence: 91%

Section: Free-piston Engine Combustionmentioning

confidence: 99%

A computational study of free-piston diesel engine combustion

2009

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“…By applying Newton's second law to the piston assembly of an FPE, the piston acceleration can be derived as in equation (7). Note that the mass is the equivalent dynamic mass of the moving parts, including the piston, connecting rod, and the moving coils or magnets.…”

Section: Fpe Controlmentioning

confidence: 99%

“…3 Automotive manufacturers such as Ford and General Motors developed FPE prototypes in the late 1950s that were used as high temperature gas generators coupled with turbines for power extraction. [4][5][6][7] The first free-piston linear alternator (FPLA) unit was patented by Ostenberg 8 in 1944. Despite the interest in FPEs until the early 1960s, their development was later decelerated because of the maturity of conventional engine and gas turbine technology in that era. Recently, however, the increasingly stringent fuel economy and emissions regulations have motivated research toward alternative powertrains that can offer superior efficiency compared to conventional engines.…”

Section: Introductionmentioning

confidence: 99%

Advanced combustion free-piston engines: A comprehensive review

Zhou

Sofianopoulos

Lawler

et al. 2018

International Journal of Engine Research

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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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“…Fleming and Bayer [15] describe how theoretical thermodynamic analysis of the engine processes had to be drastically changed to achieve good agreement with experimental data, due to long ignition delays and high heat release rate in the free-piston engine. Baruah [16] reports significant advantages in emissions for a spark ignited free-piston engine over crankshaft engines, particularly for nitric oxides.…”

Section: The Combustion Processmentioning

confidence: 99%

A review of free-piston engine history and applications

Mikalsen

Roskilly

2007

Applied Thermal Engineering

396

186

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This document reviews the history of free-piston internal combustion engines, from the air compressors and gas generators used in the mid-20th century through to recent free-piston hydraulic engines and linear electric generators. Unique features of the free-piston engine are presented and their effects on engine operation are discussed, along with potential advantages and disadvantages compared to conventional engines. The paper focuses mainly on developed engines where operational data has been reported. Finally, the potential of the free-piston engine is evaluated and the most promising designs identified.

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Diesel Combustion Phenomena as Studied in Free Piston Gasifiers

Cited by 5 publications

References 8 publications

A computational study of free-piston diesel engine combustion

A computational study of free-piston diesel engine combustion

Advanced combustion free-piston engines: A comprehensive review

A review of free-piston engine history and applications

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