Modelling of the injection and combustion processes in the gasoline direct injection engine

Rad prikazuje modeliranje procesa ubrizgavanja pomoću KIVA programa. Složeni matematički modeli koji se koriste u izračunima i koji opisuju procese koji se odvijaju unutar cilindra motora omogućuju generiranje kompliciranih virtualnih modela koji odražavaju stvarne uvjete na zadovoljavajući način. Točnost rezultata proračuna određena je kvalitetom ulaznih podataka, koji se mogu dobiti na temelju ispitivanja s modelom. Na temelju modeliranja procesa ubrizgavanja i izgaranja u GDI motoru, predstavljenih u radu, dobivena je osnova za širu analizu plinsko-dinamičkih pojava.The paper presents modelling of the injection process by means of KIVA program. The elaborate mathematical models used in calculations describing the processes occurring inside the engine cylinder make it possible to create complicated virtual models reflecting real conditions in a satisfactory way. The accuracy of calculation results is determined by the quality of input data, which can be obtained based on model investigations. Based on the modeling of injection and combustion processes in the GDI engine, presented in the work, the basis for a broader analysis of the gas-dynamic phenomena was obtained

Numerical analysis of the engine with spark ignition and compression ignition

U radu se prikazuju istraživanja simulacije izgaranja u testiranom motoru s četiri cilindra, na osnovu motora Toyote Yaris 1,3 dm3 s paljenjem iskrom i opremljenim s dva sustava napajanja energijom: osnovnim i paljenjem. Primijenjene su dvije metode pokretanja postupka izgaranja: paljenje iskrom i ponovo, poslije isključenja, ubrizgavanje zapaljive doze. Cilj je istraživanja bilo utvrđivanje razlika u postupku izgaranja i radu motora, prije svega promjena tlaka do kojih je došlo u cilindru te vrste motora s dva sustava napajanja energijom. Zapaljiva doza uštrcana u cilindar bila je jednaka otprilike 5 ÷ 8 % ukupne mase goriva u motoru. Gorivo je direktno ubrizgavano tijekom nekoliko desetaka stupnjeva rotacije koljenaste osovine prije dostizanja gornje mrtve točke. Pripremljena je prostorna mreža modela motora (predprocesor), a napravljena je i modifikacija izvornog KIVA 3V programa kako bi se uzela u obzir dva sustava ubrizgavanja. Treba spomenuti da standardni KIVA 3V program ima, po defaultu, samo jedan izvor ubrizgavanja goriva.The article presents simulation researches on the combustion process in the four-cylinder testing engine, based on the spark ignition engine Toyota Yaris 1,3 dm3 which was equipped with two systems of power supply i.e.: fundamental and ignition. Two methods of initiating the combustion process were applied: by spark ignition and, after it was turned off, by means of the ignition dose injection. The researches aimed at revealing the differences in the combustion process and engine performance, above all the changes in pressure that occurred in the cylinder for that kind of two-fuel power supply of the engine. The ignition dose injected into the cylinder was equal to about 5 ÷ 8 % of the general mass of the fuel supplied to the engine. The mass of the fuel injected into the approach collector determined the remaining part, and the direct injection of the fuel took place over several dozen of rotation degrees of the crankshaft before TDC (Top Dead Centre). A spatial grid of the engine’s model (pre-processor) was prepared, and also a modification to the source KIVA 3V program was made consisting in taking into account of two systems of injection. It is necessary to mention that the standard KIVA 3V program contains, as a default, only one source of fuel injection

Analysis of the Possibility of Elimination of Threats Resulting from the Modification of Bullet Trajectory after Hitting the Target in Garrison Shooting Ranges

. During shooting operations in garrison shooting ranges, a phenomenon of random deflection of the bullet flight path was noticed which may cause secondary reflections from accidentally hit technical and ballistic shooting range elements and the ground of the actual plane of the shooting range (ricochets posing a threat to people and property within the shooting range and safety zones). Minimisation of this phenomenon must be considered during the design and operation of the shooting ranges. In 20202022 the Military Institute of Armament Technology (Zielonka, Poland) carried out tests with the aim of determining the impact of the shooting target or military target material or design (hereinafter referred to as the targets) on the risk of occurrence of modifications of bullet trajectory that cause the bullets to leave the shooting zone. The paper presents example results of these tests that show, but are not limited to, that the reasons to modify the direction of the bullet path after target penetration and any ricochets include: target material (flat or corrugated sheet metal, cardboard, plywood, etc.), target wooden legs, and even metal elements fixing the legs to the target. On the basis of the test it was shown that the metal targets prohibited on intermediate lines may cause significant deflections of the bullet flight path after penetration and dangerous ricochets. Due to the reason presented above, the metal targets are placed on the last line of targets before the main bullet trap only where the technical and ballistic parameters of the bullet trap ensure that any ricochets are captured. It was stated that the contact targets used on intermediate target lines and provided with wooden legs may cause bullet trajectory changes comparable to or even greater than in the case of the prohibited metal targets. To this end it is advisable to establish legal framework covering the ballistic inspection of the target materials to be used in garrison shooting ranges

Does the presence of ground state complex between a PR-10 protein and a sensitizer affect the mechanism of sensitized photo-oxidation?

The mechanisms of one-electron protein oxidation are complicated and still not well-understood. In this work, we investigated the reaction of sensitized photo-oxidation using carboxybenzophenone (CB) as a sensitizer and a PR-10 protein (MtN13) as a quencher, which is intrinsically complicated due to the complex structure of the protein and multiple possibilities of CB attack.To predict and examine the possible reactions precisely, the 3D structure of the MtN13 protein was taken into account. Our crystallographic studies revealed a specific binding of the CB molecule in the protein's hydrophobic cavity, while mass spectrometry identified the amino acid residues (Met, Tyr, Asp and Phe) creating adducts with the sensitizer, thus indicating the sites of 3CB* quenching. In addition, protein aggregation was also observed.The detailed mechanisms of CB quenching by the MtN13 molecule were elucidated by an analysis of transient products by means of time-resolved spectroscopy. The investigation of the transient and stable products formed during the protein photo-oxidation was based on the data obtained from HPLC-MS analysis of model compounds, single amino acids and dipeptides.Our proposed mechanisms of sensitized protein photo-oxidation emphasize the role of a ground state complex between the protein and the sensitizer and indicate several new and specific products arising as a result of one-electron oxidation. Based on the analysis of the transient and stable products, we have demonstrated the influence of neighboring groups, especially in the case of Tyr oxidation, where the tyrosyl radical can be formed via a direct electron transfer from Tyr to CB* or via an intramolecular electron transfer from Tyr to Met radical cation Met > S●+ or thiyl radical CysS● from neighboring oxidized groups

New Arylene–Germylene–Vinylene Compounds: Stereoselective Synthesis, Characterization, and Photophysical Properties

The stereoselective route toward new molecular and macromolecular compounds containing arylene–germylene–vinylene units is described. The reagents for germylative coupling reaction were 1,4-bis­(dimethylvinylgermyl)­benzene (<b>1</b>) and vinyl- and divinylarenes with ruthenium complexes (<b>2a</b>, <b>2b</b>) as catalysts. NMR characterization of all isolated products, results of MS and elemental analysis for molecular compounds (<b>3</b>–<b>5</b>), and GPC for oligomers (<b>6</b>–<b>8</b>) are presented. Absorption and luminescence properties of the synthesized compounds are discussed and compared with those of model chromophores