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1
Content available Experimental study and modeling of an air-cooled proton exchange membrane fuel cell stack in the static and dynamic performance
Pielecha Ireneusz, Szwajca Filip
Eksploatacja i Niezawodność
|
2024
|
Vol. 26, no. 2
art. no. 184232
EN
Research on Proton Exchange Membrane fuel cells is an important area in the field of modern energy sources. Such fuel cells are characterized by high efficiency and fast response times, making them a promising solution for sustainable energy production. Fuel cells operate under both static and dynamic conditions. Such varying operating conditions result in achieving different efficiency of fuel cell systems. This study attempts an experimental and modeled efficiency evaluation of a 1.2 kW open-cathode air-cooled fuel cell stack under static and dynamic conditions. A Sankey energy balance and an analysis of the balance components were determined for the fuel cell stack operating in these two operating states. Simultaneous modeling of the fuel cell under both static and dynamic conditions was carried out. The efficiency values of the fuel cell stack were found to be slightly higher under static conditions than under dynamic conditions. Modeling fuel cells in static and dynamic conditions results in slightly different parameters (better conformance was obtained for static models).
2
Content available Numerical investigation on the effects of fueling the Turbulent Jet Ignition gas engine with methane and hydrogen
Pielecha Ireneusz, Szwajca Filip, Skobiej Kinga
Pojazdy Szynowe
|
2023
|
Nr 1-2
46--57
EN
The modern solution of two-stage combustion, namely the Turbulent Jet Ignition (TJI), enables the combustion of ultra-lean mixtures. Thanks to this solution, it became possible to reduce fuel consumption and, at the same time, to increase the combustion process indicators (including the overall combustion system efficiency). The article presents the results of numerical tests of a heavy-duty engine equipped with the TJI system running on gas fuels. The AVL BOOST software was used to analyze the effects of different fuel injection rates into the pre-chamber and various ignition timing angles, while maintaining a constant global excess air ratio. Increasing the proportion of hydrogen in the prechamber resulted in its reduction in the main chamber (the fuel dose was kept constant with different excess air coefficients in each of the chambers). The maximum combustion pressure values in both chambers were investigated. Changes in the amount of heat released and its release rate were determined. As a result of the simulations, different ignition and combustion conditions were presented for the tested fuels. Based on this, maps of fuel dose to prechamber vs. ignition advance angle were drawn up, showing selected thermodynamic indicators of the combustion process.
3
Content available Potential of ethanol and butanol in reducing deposits of SIDI engine injectors
Pielecha Ireneusz, Szwajca Filip, Stępień Zbigniew
Combustion Engines
|
2023
|
R. 62, nr 3
21--31
EN
The operation of conventional (hydrocarbon) fuels causes certain effects in the internal combustion engine. Despite the satisfactory efficiency of internal combustion engines, their fuel systems, particularly the injectors, are subject to constant fouling. The article analyzes the possibility of reducing the deposit of high-pressure gasoline injectors using the alcohol addition of ethanol and butanol. The study was conducted under the engine and non-engine conditions. Fuel injection timing was analyzed when fueling with different mixtures, and non-engine analyses were conducted to determine changes affecting the injectors. The results indicate the possibility of reducing injector hole coking using ethanol and butanol as a 20% additive to the base fuel.
4
Content available Experimental identification of the electrical discharge on a surface gap spark plug
Szwajca Filip, Wisłocki Krzysztof
Combustion Engines
|
2023
|
R. 62, nr 4
104--108
EN
The main objective of the research is to assess the influence of the spark plug electrodes geometry on the structure of the electric arc. This issue is increasingly important in modern gas-fueled engines with lean and stratified air-gas mixtures. To explain the influence of electrode geometry on selected spark discharge indicators, optical tests were conducted, and the parameters of the test history, together with the movies of the discharging process, were recorded and analyzed. The tests were carried out comparatively for two types of spark plugs on the test stand: conventional spark plug and spark plug with a flat ground electrode. It has been found that using flat plug electrodes allows a larger spark area covered by the electric arc without losing the intensity of radiation. More, using an unconventional spark plug results in a shorter discharge time relative to the conventional spark plug, while the geometry of the conventional spark plug allows for maintaining a stable electric arc with a minimum tendency for creeping.
5
Content available Characteristics of fuel cells under static and dynamic conditions
Szwajca Filip, Berger Andrew W., Spalletta Robert, Pielecha Ireneusz
Pojazdy Szynowe
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2022
|
Nr 3-4
44--52
EN
Modern internal combustion powertrains are the main source of propulsion for on-road and non-road vehicles. However, they are increasingly being replaced by electric or fuel cell-equipped alternative propulsion systems. The article presents a study of fuel cell characteristics operating under both static and dynamic conditions, with a 1.2 kW fuel cell set with a voltage converter and lead-acid batteries. In the conducted tests, the fuel cell stack's maximum efficiency reached 65%. Load tests (static and dynamic) have indicated higher fuel cell efficiencies when using hybrid operation with a DC/DC converter and battery.
6
Content available The impact of alcohol admixture with gasoline on carbon build-up and fuel injectors performance
Stępień Zbigniew, Pielecha Ireneusz, Cieslik Wojciech, Szwajca Filip
Eksploatacja i Niezawodność
|
2022
|
Vol. 24, no. 2
226--236
EN
The operating conditions of injectors in spark ignition engines with direct fuel injection make them susceptible to coking, which leads to a reduced quality of fuel atomization. This can be observed by a drop in performance and an increase in exhaust emissions, especially particulate matter. One effective method of reducing injector coking is by using detergentdispersing gasoline additives. The article describes the effect of using an admixture with a varied alcohol content on the quantitative and qualitative fuel atomization indicators. The research consisted of a 48-hour engine test, done in accordance with the CEC F-113-KC procedure (CEC-F-113 test). After each test cycle, the injectors underwent optical tests with the use of an isochoric chamber. The spray penetration and surface area were analyzed at a set of different fuel injection parameter values. The research performed resulted in determining the influence of each tested admixture on the change of injection time and on the geometric indicators of the fuel spray. The obtained characteristics of the engine in operation and conducted stationary tests enabled the operational evaluation of the impact an alcohol admixture with gasoline fuels had on key engine parameters.
7
Content available Reverse engineering of research engine cylinder-head
Cieślik Wojciech, Szwajca Filip, Wisłocki Krzysztof
Combustion Engines
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2022
|
R. 61, nr 2
73--82
EN
The pursuit of increasing the efficiency of internal combustion engines is an ongoing engineering task that requires numerous research efforts. New concepts of injection or combustion systems require preliminary investigation work using research engines. These engines, usually single-cylinder, make it possible to isolate a single variable in a complex combustion mixture preparation process, thus enabling analysis of the changes being made. However, these engines are relatively expensive and their designs are offered by a limited number of manufacturers. The authors of this paper have successfully undertaken the engineering task of modifying an existing research engine cylinder head in such a way as to implement an electronically controlled variable valve timing system of the intake system. The process of reverse engineering, together with design assumptions that finally contributed to the construction of the assumed solution has been described in this paper.
8
Content available Cooperation of a PEM fuel cell and a NiMH battery at various states of its charge in a FCHEV drive
Pielecha Ireneusz, Szwajca Filip
Eksploatacja i Niezawodność
|
2021
|
Vol. 23, no. 3
468--475
EN
The development of electromobility is focused on the design and implementation of increasingly more effective electric drives. In such a system, apart from energy recovery, it is not possible to recharge the batteries while driving. Electric vehicles equipped with fuel cells and a battery (FCHEV – fuel cell hybrid electric vehicle) in a parallel configuration boast increased energy transfer capabilities. The article presents an energy flow analysis in a parallel hybrid drive system with fuel cells and a battery. The research was carried out on a 30 W vehicle made in 1:10 scale with a NiMH battery and a fuel cell with a proton exchange membrane (PEM). Increasing driving dynamics causes a 29% increase in energy consumption, 43.6% reduction of energy transfer from a fuel cell and a 23% increase of in the energy share intended for battery charging. Continuous operation of the system in full power mode ensures a much greater efficiency of energy transmission to the drive train (95%) compared to the system operating in dynamic driving conditions – 64–75%.
9
Content available remote Thermodynamic cycles variability of TJI gas engine with different mixture preparation systems
Szwajca Filip, Wisłocki Krzysztof
Combustion Engines
|
2020
|
R. 59, nr 2
46--52
EN
Gas engines are a viable source of propulsion due to the ecological indicators of gas fuels and the large amount of the needed natural resources. Combustion of lean homogeneous gas mixtures allows achieving higher thermal efficiency values, which is a key factor in current engine development trends. Using the spark-jet ignition system (also called as Turbulent Jet Ignition or two-stage combustion) significantly improves the efficiency and stability of the combustion process, especially in the part-load operation on lean or very lean mixtures. This paper presents the impact of using two different fuel injection methods: Port Fuel Injection or mixer on the operation stability of a gas engine designed for LDVs. Comparative studies of two different mixture preparation systems were carried out on a single-cylinder AVL 5804 test engine. By recording the cylinder pressure for a significant number of engine cycles, it became possible to determine the repeatability of engine operation and to correlate the results with the mixture formation system and the air-fuel ratio. In the performed research the beneficial effect of the mixer system application on the engine operation stability in the part-load conditions was found.
10
Content available The possibility of energy consumption reduction using the ECO driving mode based on the RDC test
Cieślik Wojciech, Szwajca Filip, Golimowski Jacek
Combustion Engines
|
2020
|
R. 59, nr 3
59--69
EN
The greenhouse effect and overall climate changes are the main reasons for developing ecological powertrain units dedicated to road vehicles. An electrical drivetrain without using conventional combustion engines fueled by hydrocarbon fuels is an effective method to significantly reduce CO2 emissions from the fleet. It is particularly vital in 2020 emission regulations aspects, and continuously the number of vehicles increasing. In this paper battery electric drive system of a small size passenger car was analyzed in terms of two different drive modes in cooperation with two recuperative braking modes. The research was carried out with real driving condition test requirements and driving parameters recording. Based on data obtained from OBD signals, energy flow and torque distribution have been specified. In results, overall reducing energy consumption has been achieved with ECO mode compared to normal mode. Selection of the driving mode ECO has a positive impact on reducing the state of charge saving more than 5%, taking into account the whole RDC test; greater energy consumption reductions were observed in selected test areas.
11
Content available Prechamber optimal selection for a two stage turbulent jet ignition type combustion system in CNG-fuelled engine
Pielecha Ireneusz, Bueschke Wojciech, Skowron Maciej, Fiedkiewicz Łukasz, Szwajca Filip
Combustion Engines
|
2019
|
R. 58, nr 1
16--26
EN
Searching for further reduction of fuel consumption simultaneously with the reduction of toxic compounds emission new systems for lean-mixture combustion for SI engines are being discussed by many manufacturers. Within the European GasOn-Project (Gas Only Internal Combustion Engines) the two-stage combustion and Turbulent Jet Ignition concept for CNG-fuelled high speed engine has been proposed and thoroughly investigated where the reduction of gas consumption and increasing of engine efficiency together with the reduction of emission, especially CO2 was expected. In the investigated cases the lean-burn combustion process was conducted with selection of the most effective pre-combustion chamber. The experimental investigations have been performed on single-cylinder AVL5804 research engine, which has been modified to SI and CNG fuelling. For the analysis of the thermodynamic, operational and emission indexes very advanced equipment has been applied. Based on the measuring results achieved for different pre-chamber configurations the extended methodology of polioptimization by pre-chamber selection and the shape of main chamber in the piston crown for proposed combustion system has been described and discussed. The results of the three versions of the optimization methods have been comparatively summarized in conclusions.
12
Content available Comparative study on combustion characteristics of lean premixed CH4/air mixtures in RCM using spark ignition and turbulent jet ignition in terms of orifices angular position change
Bueschke Wojciech, Skowron Maciej, Wisłocki Krzysztof, Szwajca Filip
Combustion Engines
|
2019
|
R. 58, nr 1
36--41
EN
The increase in ignitability consist a main aim of implementation of the turbulent jet ignition (TJI) in relation to the combustion of diluted charges. Such an ignition system has been introduced to the lean-burn CNG engine in the scope of GasOn-Project (Gas Only Internal Combustion Engines). In this study the impact of TJI application on the main combustion indexes has been investigated using RCM and analyzed on the bases of the indicating and optical observations data. The images have been recorded using LaVision HSS5 camera and post-processed with Davis software. Second part of the study based on indicating measurements consist the analysis of combustion regarding the variation in the geometry of pre-chamber nozzles. It has been noted, that combustion with TJI indicates significantly bigger flame luminescence and simultaneously - faster flame front development, than the combustion initiated with conventional SI. The positive impact of nozzles angular position on engine operational data has been found in the static charge movement conditions, regarding the combustion stability.
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