First Cycles of the Dual Hydraulic Free Piston Engine

Tikkanen, Seppo; Lammila, Mika; Herranen, Mika; Vilenius, Matti

doi:10.4271/2000-01-2546

Cited by 52 publications

(41 citation statements)

References 4 publications

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“…The particular piston motion profile of the freepiston engine has been reported by a number of authors, including Achten et al [2], Tikkanen et al [5] and Mikalsen and Roskilly [8]. Figure 2 shows the simulated piston motion of a free-piston engine compared to that of a conventional engine.…”

Section: Free-piston Engine Operating Characteristicsmentioning

confidence: 66%

“…Somhorst and Achten [9] reported high heat release rates in a single piston hydraulic free-piston engine, with pressure gradi- ents reaching values of two to five times those of a comparable conventional engine. Tikkanen et al [5] reported the same behaviour in a dual piston free-piston engine and both groups stated that combustion takes place predominantly in a single, pre-mixed phase. It was suggested that this is due to the high piston velocities around TDC, increasing in-cylinder gas motion and turbulence levels [2,9].…”

Section: Free-piston Engine Combustionmentioning

confidence: 81%

“…Such engines potentially offer excellent power to weight ratios, but engine control has been reported to be a challenge. Tikkanen et al [5] described the design of a 20 kW diesel powered hydraulic free-piston engine and test results from an engine prototype demonstrated the feasibility of the concept. High cycle-to-cycle variations were reported and the developers stated that further research into engine control issues are required.…”

Section: Intake Port Piston Coilmentioning

confidence: 99%

See 2 more Smart Citations

Coupled dynamic–multidimensional modelling of free-piston engine combustion

Mikalsen

Roskilly

2009

Applied Energy

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Free-piston engines are under investigation by a number of research groups worldwide, as an alternative to conventional technology in applications such as electric and hydraulic power generation. The piston dynamics of the freepiston engine differ significantly from those of conventional engines, and this may influence in-cylinder gas motion, combustion and emissions formation. Due to the complex interaction between mechanics and thermodynamics, the modelling of free-piston engines is not straight-forward. This paper presents a novel approach to the modelling of free-piston engines through the introduction of solution-dependent mesh motion in an engine CFD code. The particular features of free-piston engines are discussed, and the model for engine dynamics implemented in the CFD code is described. Finally, the coupled solver is demonstrated through the modelling of a spark ignited free-piston engine generator.

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Section: Free-piston Engine Operating Characteristicsmentioning

confidence: 66%

Section: Free-piston Engine Combustionmentioning

confidence: 81%

Section: Intake Port Piston Coilmentioning

confidence: 99%

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Coupled dynamic–multidimensional modelling of free-piston engine combustion

Mikalsen

Roskilly

2009

Applied Energy

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“…It was suggested that this is due to the high piston velocities around TDC, increasing in-cylinder gas motion and turbulence levels [7,12]. Tikkanen et al [8] reported the same behaviour in a dual piston free-piston engine and stated that combustion takes place predominantly in a single, pre-mixed phase.…”

Section: Free-piston Engine Combustionmentioning

confidence: 93%

“…Tikkanen et al [8] described the performance of a dual piston hydraulic free-piston engine prototype. The piston motion was found to be different from that of conventional engines with piston acceleration peak values of more than double the values of comparable crankshaft engines.…”

Section: Modern Free-piston Engine Applicationsmentioning

confidence: 99%

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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