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1

The analysis of the possibilities of increasing the share of propane in the fuel mixture supplied to a dual fuel diesel engine

Skrzek T.

Combustion Engines

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2017

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R. 56, nr 2

32--37

EN

The paper presents the main reasons for the limitations as to the share of gaseous fuel in dual fueling in commercial engine applications. It also indicates the proposals of solutions aiming at increasing of the share of this fuel. The investigations were conducted in two stages. The first stage of the investigations involved gradual increase in the share of propane at a simultaneous phasing out of the amount of diesel fuel so that the excess air coefficient remained on the same level. The second stage of the investigations involved a maximum possible share of propane with a simultaneous adjustment of the diesel fuel injection parameters. The investigations were performed for three different values of the charging pressure: 200, 400, 600 mbar and for a naturally aspirated variant. The obtained results led to a conclusion that modifying diesel fuel injection parameters and increasing the charging pressure allow a significant increase in the share of gaseous fuel up to 70% of the total energy contained in both fuels.

2

Wyznaczanie naprężeń cieplnych w gniazdach zaworowych doładowanego silnika z zapłonem samoczynnym w stanie nieustalonym

Hornik A., Gustof P.

Logistyka

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2014

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nr 6

4509-4518

PL

W niniejszej pracy dokonano wyznaczenia naprężeń cieplnych gniazd zaworowych doładowanego silnika z zapłonem samoczynnym w stanie nieustalonym. Obliczenia numeryczne oparto na podstawie uzyskanych danych o własnościach materiałowych oraz fizycznych materiału z którego wykonano gniazda, jak również przeprowadzonych wcześniej badaniach eksperymentalnych silnika. Obliczenia zostały przeprowadzone przy zastosowaniu dwustrefowego modelu procesu spalania, warunków brzegowych III rodzaju oraz metody elementów skończonych (MES) za pomocą programu Cosmos/M dla początkowego okresu pracy silnika liczonego od momentu jego uruchomienia. Analizie poddano charakterystyczne powierzchnie gniazd zaworu dolotowego i wylotowego. Wyniki obliczeń numerycznych potwierdzają możliwość korzystania z przyjętego sposobu modelowania procesu spalania i przyjętych wcześniej założeń do analizy wartości i rozkładu powstających naprężeń cieplnych na różnych powierzchniach gniazd zaworowych.

EN

In this paper were designated the thermal stresses of the valve seats supercharged diesel engine in the nonstationary state. Numerical calculations were carried out based on the obtained data on the physical properties of materials and material of the socket, as well as experimental studies earlier conducted on the engine. Calculations were performed using the two-zone model of the combustion process, the boundary conditions III type and the finite element method (FEM) using the program Cosmos/M for the initial operating period counted from the moment of its launch. We analyzed the characteristic of the valve seat surfaces of the intake and exhaust. The results of numerical calculations confirm the possibility of using the method of modeling the combustion process as well as adopted earlier assumptions to the analysis and decomposition of thermal stresses for various surfaces of the valve seats.

3

Hydrogen combustion in the supercharged SI engine

Grab-Rogaliński K., Szwaja S.

Journal of KONES

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2012

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Vol. 19, No. 3

149-155

EN

The experimental results of combustion pressure processing from a supercharged spark ignition (SI) engine that was running on hydrogen are exposed in the paper. Hydrogen was delivered in two ways by an injector and mixer installed in an intake port. In-cylinder pressure while combusting hydrogen was analyzed with various coefficient of stechiometry and boost pressure. These parameters were limited by abnormal combustion known as "knock" combustion. Hydrogen fueled engine has tendency to generate "knock", especially this abnormal combustion phenomena increases with increase in boosting pressure. Hence, the thermodynamic parameters such as pressure and temperature of fresh air fuel mixture are elevated. The experimental numeric data analysis permit for compare to naturally aspirated engine such parameters as mean indicated pressure, indicated efficiency. Also for both cases, the coefficient of variation for mean indicated pressure was determined. It was found that combustion duration shortens itself with higher boosting pressure. Thus, optimal spark timing to get the maximum indicated mean effective pressure is shifted closer to the TDC. Another parameter that was expected to be increased was the knock intensity. It was observed, that knock intensity did not increase significantly and was still below the limit for pressure pulsations treated as combustion noise coming from light combustion instabilities.