Wyniki wyszukiwania - BazTech

1

Methods of determining ignition advance angle maps

Fudalej-Kostrzewa E.

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

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2016

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z. 4/108

111--117

EN

Methods of determining ignition advance angle maps based on adjustment characteristics of ignition advance angle determined at constant engine speed and constant vacuum pressure are presented in this article. Application of those characteristics is proposed (envelope method) and described. The criteria for the selection of proper ignition advance angle value are formulated. The procedure leading to determining the ignition advance angle value based on assumed criteria as well as and maps suitable for all engines certain type is presented.

PL

W pracy zaprezentowano metodę wyznaczania map kąta wyprzedzenia zapłonu w oparciu o zbiór charakterystyk regulacyjnych kąta wyprzedzenia zapłonu sporządzonych przy stałej prędkości obrotowej i stałym podciśnieniu. Zaproponowano (metoda obwiedniowa) i opisano sposób wykorzystania tych charakterystyk, sformułowano kryteria wyboru właściwych wartości kąta wyprzedzenia zapłonu. Przedstawiono tok postępowania prowadzący do wyznaczenia wartości kąta wyprzedzenia zapłonu przy założonych kryteriach i sporządzenia map odpowiednich dla wszystkich silników określonego typu.

2

Experimental comparative studies of injection systems

Dziubiński M., Drozd A., Siemionek E., Plich M.

Prace Naukowe Politechniki Warszawskiej. Transport

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2016

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z. 112

79--88

EN

The maintenance of modern means of transport requires an assessment of energy consumption. This paper presents a methodology for testing electric wheelchair. The analysis of vehicle movement and the knowledge of forces affecting the vehicle are necessary to determine the components of energy balance, such as kinetic energy, energy of rolling resistance and losses in the power transmission system. The study was conducted for three different driving cycles. The motion parameters for each of the driving cycles were analyzed. The control electronics in electric wheelchair drives converts the commands of the driver: direction, accelerator, brake pedał position, into the corresponding control commands input to the power semiconductors, while at the same time observing specified limits: current, voltage, motor speed. The paper describes a research method for testing a wheelchair eąuipped with electric engine. The tests were conducted for specified operating conditions involving the following constrained motion on a horizontal road section. The effect of selected operating parameters on the work of the electric drive system was investigated. The paper also gives examples of the results if the conducted road tests of the wheelchair. The object of the tests was the electric wheelchair. The vehicle is suitable for transporting people weighing 80 kg. Two electric engines powered by batteries with the voltage of 24 V were used for driving the vehicle.

3

Modelowanie obiegu cieplnego czterosuwowego silnika tłokowego o zapłonie iskrowym

Jamrozik A.

Modelowanie Inżynierskie

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2014

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T. 20, nr 51

28--34

PL

W pracy przedstawiono wyniki modelowania pełnego obiegu cieplnego tłokowego silnika spalinowego o zapłonie iskrowym. Modelowanie przeprowadzono w programie AVL Fire. Zaprezentowano wyniki walidacji modelu oraz wyniki numerycznej optymalizacji zapłonu w silniku badawczym. Modelowanie umożliwiło określenie optymalnego wyprzedzenia zapłonu silnika podczas spalania mieszanki stechiometrycznej. Optymalizacja polegała na znalezieniu kata wyprzedzenia zapłonu, przy którym silnik charakteryzował się maksymalnym ciśnieniem indykowanym oraz sprawnością indykowaną i jednocześnie nie wykazywał objawów spalania stukowego.

EN

The results of modeling of total thermal cycle of spark ignition internal combustion engine are presented. Modeling was carried out in the AVL Fire. The numerical analysis results have been juxtaposed with the results of indicating the engine on the test stand. This paper presents results of numerical optimization of ignition advance angle in the modernized the test engine, during the combustion of fuel mixture with an excess air factor l = 1.0. The optimum value of the angle was that which occurred at the maximum indicated pressure and indicated efficiency and for which there was no combustion knock

4

Some problems of combustion system operation with semi-open combustion chamber for spark ignition engine

Leżański T., Sęczyk J., Wolański P.

Journal of KONES

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2010

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Vol. 17, No. 4

287-294

EN

The some problems concern of the new combustion system operation with semi open combustion chamber, which can be used in spark ignitions internal combustion engines are presented in this paper. These considerations are based on the visualization research results, with using rapid compression machine (RCM). In this researched combustion system the original combustion chamber was divided by partition in prechamber and main combustion chamber. This division of the original combustion chamber exists only when the piston is close to TDC, for the rest of the cycle the chambers arefully open. Ignition is initiated in the prechamber using electric spark plug, but the mixture in main combustion chamber is ignited by the stream of the burned gases injected from prechamber through the orifice in partition, if the ignition advance angle is correct. If the ignition advance angle is incorrect the mixture from prechamber will be outflowing through the orifice in partition and through the slot which is created between the partition and piston crowns. This last stream is swirled on the partition edge, what causes decrease of the stream speed outflowed from the orifice in partition to main combustion chamber. If the ignition advance angle is too big, then a peak pressure and compression work is very big because the burned gases are compressed instead of the fresh air/fuel mixture. This causes that the effective work is small and combustion efficiency is small.