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contributor authorBlantin, Jason R.
contributor authorPolanka, Marc D.
contributor authorAusserer, Joseph K.
contributor authorLitke, Paul J.
contributor authorBaranski, Jacob A.
date accessioned2019-02-28T10:56:50Z
date available2019-02-28T10:56:50Z
date copyright4/24/2018 12:00:00 AM
date issued2018
identifier issn0742-4795
identifier othergtp_140_07_072803.pdf
identifier urihttp://yetl.yabesh.ir/yetl1/handle/yetl/4251063
description abstractEfforts to improve the range and endurance of group 2 (10–25 kg), internal combustion engine (ICE) powered unmanned aerial vehicles (UAVs) have been underway for several years at Air Force Research Laboratory (AFRL). To obtain the desired performance improvements, research into improving the overall efficiency of the ICE powerplants is of great interest. The high specific energy of hydrocarbon fuels (13,000 W h/kg for gasoline), but low fuel conversion efficiency for small ICEs means that relatively minor improvements in the fuel conversion efficiency of the engines can yield large improvements in range and endurance. Little information is available however for the efficiency of ICEs in the size range of interest (10–200 cm3 displacement volume) for group 2 UAVs. Most of the currently available efficiency data for 10–200 cm3 ICEs is for two-stroke engines. The goal of this study was to provide an in-depth probe of the efficiency and energy losses of a small displacement four-stroke engine which could potentially be used to power a group 2 UAV. Energy balances were performed on a Honda GX120 four-stroke engine using empirical research methods. The engine was a 118 cm3 displacement, single cylinder ICE. Energy pathways were characterized as a percentage of the total chemical energy available in the fuel. Energy pathways were characterized into four categories: brake power, cooling load, exhaust sensible enthalpy and incomplete combustion. The effect of five operating parameters was examined in the study. Fuel conversion efficiency ranged from 22.2% to 25.8% as engine speed was swept from 2000 to 3600 RPM, from 20.8% to 27.3% as equivalence ratio was swept from 0.85 to 1.25, and from 15.7% to 24.9% as throttle was swept from 28.5% to 100%. Combustion phasing and cylinder head temperature sweeps showed only minor changes in fuel conversion efficiency.
publisherThe American Society of Mechanical Engineers (ASME)
titleEnergy Balance and Power Loss Pathway Study of a 120 cc Four-Stroke Internal Combustion Engine
typeJournal Paper
journal volume140
journal issue7
journal titleJournal of Engineering for Gas Turbines and Power
identifier doi10.1115/1.4038881
journal fristpage72803
journal lastpage072803-10
treeJournal of Engineering for Gas Turbines and Power:;2018:;volume( 140 ):;issue: 007
contenttypeFulltext


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