Performance Measurement and Scaling in Small Internal Combustion Engines

Menon, Shyam

doi:10.2514/6.2003-671

Cited by 19 publications

(11 citation statements)

References 2 publications

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“…With even rudimentary heat losses included in the scaling, however, it can be shown that the improvement in power density with decreasing size effectively terminates at characteristic dimensions around a millimeter [95]. Furthermore, as Cadou et al [96,97] has demonstrated, the promise of the cube-square law is not realized in practice at all, as the performance of small-scale engines does not increase with decreasing scale. In addition to the combustion challenges mentioned above, performance also degrades because of increased friction, reduced turbulent mixing, higher viscous drag, combustion wall quenching, and sealing inefficiencies, among others.…”

Section: Combustion Issuesmentioning

confidence: 98%

“…The existence of liquid films in full-size automotive engines is problematic because films can lead to lower fuel economy, higher soot emissions, and increased deposit formation. Further diagnostic intervention is required to confirm if these same effects occur for the mesoscale, but such investigations are beginning to develop [93,96,97,163].…”

Section: Internal Combustion Engine Approachesmentioning

confidence: 99%

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Dunn‐Rankin

Leal

Walther

2005

Progress in Energy and Combustion Science

241

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Section: Combustion Issuesmentioning

confidence: 98%

Section: Internal Combustion Engine Approachesmentioning

confidence: 99%

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Dunn‐Rankin

Leal

Walther

2005

Progress in Energy and Combustion Science

241

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“…Many of the major components cannot be simply reduced in order to achieve proper functioning and it is likely that the micro scale engine is to be very different from the macro scale known to us [6]. Research has shown that a power law was found that relates engine power to engine mass [8]. Physical processes such as combustion, heat transfer and gas exchange are to be re-evaluated at a fundamental level before they may be applied to micro-engines.…”

Section: Physical Limitation Aspectsmentioning

confidence: 99%

“…A relatively long term and growing relationship with internal combustion engines proposes a means of conversion. Even with efficiencies as low as 5%, ICE converted hydrocarbon fuels are the focus of many research groups [8].…”

Section: Introductionmentioning

confidence: 99%

Miniaturization limitations of HCCI internal combustion engines

Sher

Levinzon-Sher

Sher

2009

Applied Thermal Engineering

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“…Table 1 presents estimates for the power, speed, and fuel flow rate that are expected for several small engines that could be used to power small UAVs. Most of these estimates come from engine manufacturers' information, but torque and fuel consumption are estimated using methods reported elsewhere [21]. The entries in the table show that several factors complicate performance measurements in these small engines.…”

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confidence: 99%

Development of a Dynamometer for Measuring Small Internal-Combustion Engine Performance

Menon

Moulton

Cadou

2007

Journal of Propulsion and Power

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Small hobby engines with masses less than 1 kg are attractive for use in low-cost unmanned air vehicles, because they are mass-produced and inexpensive. However, very little information about their performance is available in the scientific literature. This paper describes the development of a dynamometer system suitable for measuring the power output and efficiency of these small engines and presents detailed performance measurements for a particular engine with a mass of 150 gm that could be suitable for powering a low-cost unmanned air vehicle. When the mixture setting is adjusted according to the manufacturer's instructions, the peak power of this engine is 112 W at 9450 rpm with a brake specific fuel consumption of 3:0 kg=kWh. The performance can be improved to 159 W at 12,000 rpm and brake specific fuel consumption of approximately 2:1 kg=kWh by controlling the mixture.Nomenclature F = force f a , f m = atmospheric factor and engine factor I = moment of inertia k lc = stiffness of the load cell L=D = lift/drag ratio of the vehicle m = mass of the additional weight added to the engine cradle _ m = mass flow rate N nat = engine speed associated with the natural frequency of the cradle-load cell system P = measured output power P r = corrected power under standard reference conditions p, p r = test pressure and standard reference pressure p sr , p s = test saturated water vapor pressure and standard reference saturated water vapor pressure Q r = heating value q = fuel mass per cycle per liter of air q c = corrected specific fuel delivery R = length of the moment arm r = distance between added mass and cradle axis of rotation r r = boost pressure ratio T r , T = test ambient air temperature and standard reference ambient air temperature c = atmospheric correction factor = overall damping coefficient for cradle bearings = measured engine torque max = maximum deflection of the load cell = efficiency e = angle of cradle associated with steady state operation = density of air, mixture, methanol, nitromethane, and castor oil r , = test relative humidity and standard reference relative humidity = volume fraction of methanol, nitromethane, and castor oil in the fuel f = fuel mass fraction at takeoff ! = engine speed ! n = natural frequency of the system Subscripts a = air CH 3 OH = methanol CH 3 NO 2 = nitromethane c = cradle e = engine f = fuel lc = load cell o = overall oil = castor oil p = propulsive th = thermal

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Performance Measurement and Scaling in Small Internal Combustion Engines

Cited by 19 publications

References 2 publications

Personal power systems

Personal power systems

Miniaturization limitations of HCCI internal combustion engines

Development of a Dynamometer for Measuring Small Internal-Combustion Engine Performance

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