Comparative Evaluation of the Effects of Variable Spark Timing and Ethanol-Supplemented Fuel Use on the Performance and Emission Characteristics of an Aircraft Piston Engine

Nowadays, there are many studies that have been conducted in order to reduce the emissions of modern reciprocating engines without, at the same time, having a negative impact on the performance characteristics. One method to accomplish that is by using ethanol-supplemented fuels instead of conventio...

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Main Authors: Roussos Papagiannakis, Nikolaos Lytras
Format: Article
Language:English
Published: MDPI AG 2025-06-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/13/3440
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author Roussos Papagiannakis
Nikolaos Lytras
author_facet Roussos Papagiannakis
Nikolaos Lytras
author_sort Roussos Papagiannakis
collection DOAJ
description Nowadays, there are many studies that have been conducted in order to reduce the emissions of modern reciprocating engines without, at the same time, having a negative impact on the performance characteristics. One method to accomplish that is by using ethanol-supplemented fuels instead of conventional gasoline. On the other side of the spectrum, spark timing is one of the most important parameters that affects the combustion mechanism inside a reciprocating engine and is basically controlled by the ignition advance of the engine. Therefore, the main purpose of this study is to investigate the effect of spark timing alteration on the performance characteristics and emissions of a modern reciprocating, naturally aspirated, aircraft SI engine (i.e., ROTAX 912s), operated under four different engine operating points (i.e., combination of engine speed and throttle opening), by using ethanol-supplemented fuel. The implementation of the aforementioned method is achieved through the use of an advanced simulating software (i.e., GT-POWER), which provides the user with the possibility to completely design a piston engine and parameterize it, by using a comprehensive single-zone phenomenological model, for any operating conditions in the entire range of its operating points. The predictive ability of the designed engine model is evaluated by comparing the results with the experimental values obtained from the technical manuals of the engine. For all test cases examined in the present work, the results are affiliated with important performance characteristics, i.e., brake power, brake torque, and brake-specific fuel consumption, as well as specific NO and CO concentrations. Thus, the primary objectives of this study were to examine and evaluate the results of the combination of using ethanol-supplemented fuel instead of gasoline and the alteration of the spark timing, to asses their effects on the basic performance characteristics and emissions of the aforementioned type of engine. By examining the results of this study, it is revealed that the increase in the ethanol concentration in the gasoline–ethanol fuel blend combined with the increase in the ignition advance might be an auspicious solution in order to meliorate both the performance and the environmental behavior of a naturally aspirated SI aircraft piston engine. In a nutshell, the outcoming results of this research show that the combination of the two methods examined may be a valuable solution if applied to existing reciprocating SI engines.
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spelling doaj-art-956263f24c054909b45dbc21d4e854d72025-08-20T02:35:59ZengMDPI AGEnergies1996-10732025-06-011813344010.3390/en18133440Comparative Evaluation of the Effects of Variable Spark Timing and Ethanol-Supplemented Fuel Use on the Performance and Emission Characteristics of an Aircraft Piston EngineRoussos Papagiannakis0Nikolaos Lytras1Thermodynamic & Propulsion Systems Section, Aeronautical Sciences Department, Hellenic Air Force Academy, Dekelia Air Base, 13671 Acharnes, Attikis, Greece115 Combat Wing, Hellenic Air Force, Souda Air Force Base, 73500 Sternes, Crete, GreeceNowadays, there are many studies that have been conducted in order to reduce the emissions of modern reciprocating engines without, at the same time, having a negative impact on the performance characteristics. One method to accomplish that is by using ethanol-supplemented fuels instead of conventional gasoline. On the other side of the spectrum, spark timing is one of the most important parameters that affects the combustion mechanism inside a reciprocating engine and is basically controlled by the ignition advance of the engine. Therefore, the main purpose of this study is to investigate the effect of spark timing alteration on the performance characteristics and emissions of a modern reciprocating, naturally aspirated, aircraft SI engine (i.e., ROTAX 912s), operated under four different engine operating points (i.e., combination of engine speed and throttle opening), by using ethanol-supplemented fuel. The implementation of the aforementioned method is achieved through the use of an advanced simulating software (i.e., GT-POWER), which provides the user with the possibility to completely design a piston engine and parameterize it, by using a comprehensive single-zone phenomenological model, for any operating conditions in the entire range of its operating points. The predictive ability of the designed engine model is evaluated by comparing the results with the experimental values obtained from the technical manuals of the engine. For all test cases examined in the present work, the results are affiliated with important performance characteristics, i.e., brake power, brake torque, and brake-specific fuel consumption, as well as specific NO and CO concentrations. Thus, the primary objectives of this study were to examine and evaluate the results of the combination of using ethanol-supplemented fuel instead of gasoline and the alteration of the spark timing, to asses their effects on the basic performance characteristics and emissions of the aforementioned type of engine. By examining the results of this study, it is revealed that the increase in the ethanol concentration in the gasoline–ethanol fuel blend combined with the increase in the ignition advance might be an auspicious solution in order to meliorate both the performance and the environmental behavior of a naturally aspirated SI aircraft piston engine. In a nutshell, the outcoming results of this research show that the combination of the two methods examined may be a valuable solution if applied to existing reciprocating SI engines.https://www.mdpi.com/1996-1073/18/13/3440reciprocating SI enginenaturally aspiratedethanol-supplemented fuelspark timingperformanceemissions
spellingShingle Roussos Papagiannakis
Nikolaos Lytras
Comparative Evaluation of the Effects of Variable Spark Timing and Ethanol-Supplemented Fuel Use on the Performance and Emission Characteristics of an Aircraft Piston Engine
Energies
reciprocating SI engine
naturally aspirated
ethanol-supplemented fuel
spark timing
performance
emissions
title Comparative Evaluation of the Effects of Variable Spark Timing and Ethanol-Supplemented Fuel Use on the Performance and Emission Characteristics of an Aircraft Piston Engine
title_full Comparative Evaluation of the Effects of Variable Spark Timing and Ethanol-Supplemented Fuel Use on the Performance and Emission Characteristics of an Aircraft Piston Engine
title_fullStr Comparative Evaluation of the Effects of Variable Spark Timing and Ethanol-Supplemented Fuel Use on the Performance and Emission Characteristics of an Aircraft Piston Engine
title_full_unstemmed Comparative Evaluation of the Effects of Variable Spark Timing and Ethanol-Supplemented Fuel Use on the Performance and Emission Characteristics of an Aircraft Piston Engine
title_short Comparative Evaluation of the Effects of Variable Spark Timing and Ethanol-Supplemented Fuel Use on the Performance and Emission Characteristics of an Aircraft Piston Engine
title_sort comparative evaluation of the effects of variable spark timing and ethanol supplemented fuel use on the performance and emission characteristics of an aircraft piston engine
topic reciprocating SI engine
naturally aspirated
ethanol-supplemented fuel
spark timing
performance
emissions
url https://www.mdpi.com/1996-1073/18/13/3440
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AT nikolaoslytras comparativeevaluationoftheeffectsofvariablesparktimingandethanolsupplementedfueluseontheperformanceandemissioncharacteristicsofanaircraftpistonengine