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1

Selected aspects of the use of gaseous fuels blends to improve efficiency and emission of si engine

Kubica Grzegorz, Flekiewicz Marek, Marzec Paweł

Transport Problems

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2019

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T. 14, z. 1

95--103

EN

The paper presents results of SI engine tests, carried on for different gaseous fuels. The analysis carried out made it possible to define the correlation between fuel composition and engine operating parameters. Tests cover various gaseous mixtures: methane with hydrogen and LPG with DME. The first group, considered as low carbon content fuels, can be characterized by low CO2 emissions. The flammability of hydrogen added in those mixtures realizes the function of combustion process activator and improves the energy conversion. The second group of fuels is constituted by LPG and DME mixtures. DME mixes perfectly with LPG and differently than in the case of other hydrocarbon fuels also consisting of oxygen, which makes the stoichiometric mixture less oxygen demanding. In the case of this fuel, improvement in engine volumetric and overall engine efficiency has been noticed, compared to LPG. During the tests, standard CNG/LPG feeding systems have been used, which underlines the utility value of the research.

2

Nowoczesne autobusy – obniżenie poziomu emisji zanieczyszczeń i hałasu na przestrzeni lat

Filipczyk J., Łazarz B.

Komunikacja Publiczna

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2015

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nr 2

17--27

PL

Poprawa stanu środowiska w centrach miast jest możliwa poprzez prowadzenie ruchu tranzytowego poza miastem, ograniczanie ruchu samochodów o wyższym stopniu emisji, a także zastępowanie transportu indywidualnego środkami transportu zbiorowego. Autobus, jako najbardziej uniwersalny środek transportu miejskiego, może w znacznej mierze zastąpić indywidualny transport osobowy w centrach miast, pod warunkiem spełnienia wymagań w zakresie ograniczenia do minimum emisji spalin i hałasu.

3

Various designs of the two-stroke engine heads with the valve flushed system

Łoza Ł., Kaźmierczak A., Borkowska J., Skorupa P., Krakowian K., Cienciała M.

Journal of KONES

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2015

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Vol. 22, No. 4

187--190

EN

The two-stroke engines have never acquired the popularity of the four-stroke engines due to their inherent performance limitations. The tasks of many engineering teams were to find the basic causes, which resulted in the inferior performance of these engines. Today’s task is to build a two-stroke engine whose performance could match that of a four-stroke engine in areas of common use. The most typical performance problems of a two-stroke engine are high petrol consumption caused by low efficiency, toxic by-products of combustion being emitted into the atmosphere (caused by oil present in the petrol), and uneven and loud engine noise. The greatest challenge is to achieve a good chamber purge during one stroke in which the fresh fuel mixture flows through the piston-controlled inlet port while at the same time the fumes are being exhausted through the outlet port. This in contrast with the four-stroke engines where the intake and exhaust are each done with two separate strokes. From the energy point of view, the two-stroke engine is not efficient because a certain amount of fresh fuel is being wasted in the exhaust fumes. We propose to replace the piston-controlled cam with the valve-flushed system, which will cause the combustion process to become more efficient. The purpose of this paper is to present various designs of the engine heads and analyse their performance. The goal of this proposal is to choose the best combination of these engine heads in order to achieve the optimum overall engine performance.

4

The development of a simplified test rig for measuring the average friction torque of the piston-crank-slider mechanism of an internal combustion engine

Livanos G. A.

Scientific Problems of Machines Operation and Maintenance

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2009

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Vol. 44, nr 4

61-69

EN

The objective of this paper is to present a simplified friction measurement test cell for measuring the friction, developed on the main components of the piston-crank-slider mechanism of an internal combustion engine, including complete piston ring packs, piston skirts, connecting rod bearings and crankshaft main bearings. In detail, the main objective of this study was to measure average friction torque absorbed by an engine in motoring conditions. The proposed cell consists of an AC electric motor driving the piston-crank-slider mechanism of a typical, small, single cylinder, four-stroke engine. Several experimental runs were performed using this cell and the obtained results were compared with results from a detailed numerical engine friction simulation code, previously developed and published by the author(s) [Livanos et al]. Good agreement was found between simulation and experimental results, indicating that the proposed cell is capable of adequately predicting the dynamic friction behaviour of rotating and oscillating engine main components.