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Comparative analysis of theoretical cycles of independent valve control systems of the SI engine

Żmudka Zbigniew, Postrzednik Stefan

Combustion Engines

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2024

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R. 63, nr 2

15--21

EN

The objects of the study were theoretical cycles of the load control systems and charge exchange process in the naturally aspirated SI engine, including classic, quantitative throttling control (Seiliger-Sabathe open cycle); a system with late inlet valve closing LIVC (the Atkinson-Miller open cycle); a system with early inlet valve closing EIVC; a system with early exhaust valve closing EEVC, enabling internal exhaust gas recirculation; system of fully independent valve control FIVC. The aim of using camless independent valve control algorithms is to eliminate the throttle as an control valve for load and filling control of the SI engine, while retaining quantitative load control. The research aims to select the camless valve control algorithm most beneficial in terms of energy (the highest effective efficiency) and economy (the lowest fuel consumption).

2

Improving the effective efficiency of a spark ignition engine through the use of a fully independent valve control system

Żmudka Zbigniew, Postrzednik Stefan

Combustion Engines

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2021

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R. 60, nr 4

30--35

EN

The article presents theoretical research of the proposed system of fully independent valve control (FIVC) of the SI engine. The analysis included controlling the movement of the intake valves, which results in adjusting the mass of the fresh charge to the current engine load, as well as the movement of the exhaust valves, where the main aim is to keep the rest of the exhaust gas in the cylinder, i.e. implementation of internal EGR. The open theoretical Seiliger-Sabathe cycle with the classic throttle regulation of load is the reference cycle for assessment of benefits and study of the effectiveness of obtaining work as a result of application of the FIVC system. A comparative analysis of the effectiveness of application of the proposed system was carried out based on the selected quantities: fuel dose, cycle work, relative work of charge exchange and cycle efficiency. The use of the FIVC to regulate the SI engine load makes it possible to eliminate the throttle and thus reduce the charge exchange work, especially in the partial load range. And this then leads to an increase in internal and effective work, which in turn results in an increase in the effective energy efficiency of an engine operation.

3

Inverse problem of selection of the theoretical cycle for the real cycle of internal combustion engine

Żmudka Zbigniew, Postrzednik Stefan, Przybyła Grzegorz

Journal of KONES

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2019

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Vol. 26, No. 2

197--204

EN

The effectiveness of work of an internal combustion engine can be assessed by means of the energy efficiency: theoretical, internal and effective... In the problem regarding the efficiency of obtaining a work from the tested SI engine, the theoretical Seiliger-Sabathe cycle was adopted as a reference model for the real engine cycle. For comparison, the OTTO cycle was also analysed. The engine indicating allows direct determination only of internal work. However, determining the work of the theoretical cycle first requires solving the problem of selecting the parameters of the theoretical cycle, according to the real cycle of the engine (inverse problem). In order uniquely to determine the course of the theoretical Seiliger-Sabathe cycle, it is necessary to determine the parameters of the starting point and the heat distribution number. The selection of the theoretical cycle for the real cycle, within the scope of determining the number of heat distribution, is to some extent of a contractual nature. Therefore, the problem of determining the number of heat distribution was solved by two own original methods. A comparison of the real cycle with the theoretical cycle determined for it is presented.

4

Koncepcja i efektywność układu regazyfikacji ciekłego gazu ziemnego (LNG)

Postrzednik Stefan, Żmudka Zbigniew

Energetyka

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2019

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nr 10

678--682

PL

Zaprezentowano koncepcję oryginalnych układów do elektywnego zgazowania (regazyfikacji) ciekłego gazu ziemnego (LNG - Liquelied Natural Gas), w których istotną rolę odgrywa silnik spalinowy zasilany gazem ziemnym oraz napędzający pompę ciepła. Energia potrzebna do zgazowania LNG może pochodzić z: entalpii spalin oraz ciepła chłodzenia zainstalowanego silnika spalinowego, ciepła dostarczanego przez zainstalowane w układzie pompy ciepła oraz ciepła wyprowadzanego z niskotemperaturowego obiegu termodynamicznego. Proponowane układy charakteryzują się wysoką elektywnością energetyczną. Mogą być budowane jako zestawy mobilne, o różnej wydajności, być wykorzystywane lokalnie, w dowolnym miejscu na terenie kraju.

EN

Presented is the concept of original sytems for efficient gasification (regasilication) of the liquilied natural gas (LNG) where the important role is played by a combustion engine fuelled with natural gas and propelling a heat pump. Energy needed for LNG gasification may be obtained from such sources like enthalpy of flue gases and heat from the combustion engine cooling circuit, heat delivered by heat pumps installed in the system as well as from heat taken from the low-temperature thermodynamic cycle. The proposed systems are characterised by a high energy efficiency. They can be built as mobile systems of different capacity and applied either locally or anywhere on the territory of a country.