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1

The impact of camshaft control on combustion processes in a compression ignition VCR engine

Merkisz Jerzy, Bajerlein Maciej, Daszkiewicz Paweł, Urbański Patryk

Journal of civil engineering and transport

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2020

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Vol. 2, No. 1

9--18

EN

The article contains an analysis of thermodynamic indicators of the CI engine1 with direct fuel injection. The tested unit was an engine with an unconventional crank-piston configuration, in which at a constant compression ratio, different engine crankshaft control variants were compared In this article the time ranges in which the piston was located in the TDC2 were analyzed. Additionally, tests were carried out on a conventional unit for comparative purposes. For the purposes of the work, a piston displacement characteristic was generated in dynamic analysis in SolidWorks Motion3. Then, this characteristic was used in the simulations of the combustion process in the AVL Fire program, where the most important thermodynamic indicators of the engine cycle were analyzed.

PL

Artykuł zawiera analizę wskaźników termodynamicznych procesu spalania silnika CI z bezpośrednim wtryskiem paliwa. Badaną jednostką był silnik o niekonwencjonalnym układzie korbowo-tłokowym, w którym przy stałym stopniu sprężania poprzez wysterowanie krzywki w silniku porównano różne warianty jej ustawienia. W niniejszym artykule poddane analizie zostały zakresy czasowe w jakich tłok znajdował się w Górnym Martwym Punkcie (GMP). Dodatkowo w celach porównawczych przeprowadzono badania na jednostce konwencjonalnej. Na potrzeby pracy wygenerowana została droga tłoka w analizie dynamicznej w programie Solidworks Motion. Następnie charakterystyka ta została wykorzystana w symulacjach procesu spalania w programie AVL Fire, gdzie analizie zostały poddane najważniejsze wskaźniki termodynamiczne obiegu silnikowego.

2

Concept of sagnac effect application in measurement of angular acceleration of piston engine crankshaft

Łutowicz M.

Journal of KONES

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2014

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Vol. 21, No. 4

319--326

EN

In the paper results of conducted in Polish Naval Academy researches aiming to diagnostic using of measurement of engine crankshaft unsteady angular speed measurement will be presented. Similar works were many times started in different research centres. Up to now, adequate accuracy of measurement had not been achieved to make proper diagnostic decision. In commercial field, measurement of unsteady rotation speed has been used only in MAPEX –TV system (Torsional Vibration detector) dedicated to SULZER engines, which up to now without any mistakes detected only the one engine cylinder switch out of work. To the advanced diagnostic system, there are a lot off work to do. For several years in navigation, more often are used optic gyroscopes, which work on the base of Sagnac effect, assuring angular speed measurements, with 0.001 o/h resolution. Such resolution is absolutely higher than needed in piston engines diagnostic, but range of measured rotation speed is much lower than rpm of low speed marine diesel engines. In scope of conducted scientific work, it was decided to build of model of Sagnac interferometer prepared to measure rotational speed in range adequate to medium speed marine diesel engines. At rotational speed, equal 750 rpm 1 mV change in output voltage had been achieved for the difference of 0.4 o/sec of rotational speed. Time of measurement is equal the time, which need light to go through distance of 100 m fibber-optic line. In practice, this method does not introduce any significant phase shifts and does not limit the number of samples per revolution.

3

Unsteady angular speed of diesel engine crankshaft preliminary examination

Łutowicz M.

Journal of KONES

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2012

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Vol. 19, No. 4

393-399

EN

The paper discusses issues related to measurement of unsteady angular speed of diesel engine crankshaft. The focus is on the selection and optimization of the measuring method to obtain high accuracy, eliminating errors resulting from the unsteady angular speed of markers on diesel engine crankshaft. A method that uses a counter markers placed on the engine flywheel had been worked out. Markers location has been read out by two slit optical sensors. Number of markers and the distance between the sensors were chosen so as to counter tooth during the transition between the sensors count the more than 10,000 pulses at rated speed of the shaft. This provided a measurement method resolution at 0.01 %. Initial studies were performed on one-cylinder diesel engine with the greatest unsteady of angular speed. Additionally analysis which treated the measured unsteady angular speed of diesel engine crankshaft as a deforming pressure mapping as a function of the calculated piston movement was performed. This deformation is caused by the assumption that a constant rotation speed is proportional to time, and measurements are made at a constant rate. In the case of synchronized measurements of PLL circuits duplicating markers on the shaft against the expectations the deformations due to the activity of the follow-up mode of such systems are increased. The influence of these deformations on the designation of an average error of cylinder indicated pressure and other parameters obtained from the analysis of the pressure and vibration envelope has been examined.

4

Influence of indicator valve channel untightens and loss of patency on the parameters values image obtained from indicator diagram

Cuper D., Łutowicz M.

Journal of KONES

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2011

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Vol. 18, No. 3

61-66

EN

Indication process of big marine and industrial diesel engines are taken through indicating canals with indicating valves. Influence of these channels on parameters values obtained from engines indication is significant. Depending on chosen method of TDC determination the obtained image course error could achieved even 80% of measured value. It is assumed that this error is systematic and identical for whole engine cylinders or even for whole the same engines type. From these reasons such measurement are commonly used only for comparative tests. Engines exploitation caused technical degradation of indicators canals and valves. Unburnt fuels and oil particles deposits in channel changing its patency and also untightens in connections occurs. These are the reasons of changing in indication pressure diagram image. Process of degradation could be treated as random and measured parameters could be also burden by random error. During tests which were carried out on Sulzer type 6AL20/24 engine simulations of indicator canal malfunctions were made and their influence on obtained indication parameters were checked. Obtained parameters devalue sense of engine tuning in exploitation which based only on comparative tests of indicating pressure curves.

5

Determination of the mechanical power losses of engine-compressor GMVH for diagnostic purposes

Łutowicz M.

Journal of KONES

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2010

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Vol. 17, No. 3

279-286

EN

The engine-compressors GMVH types are used in the national gas transmission system in Poland. There is a danger of scuffing of the working components of the engine-compressor particular pistons and cylinders during the process of their exploitation. The growth of resistance in motion parts of the machine is the main symptom of the scuffing. In the cinematic system of the engine-compressor where the engine and compressor are fully mechanically integrated it is impossible to assess the power of mechanical friction without stopping the machine. But if the engine-compressor is equipped with a cylinder pressure measuring system it is possible to determine the indicated power of all compressor and engine cylinders and assess the friction losses as a difference between the sum of the engine 's cylinder s indicated power and the sum of the compressor's cylinders indicated power. In the differential measurements of absolute values measuring errors are accumulated so considerable uncertainty of the measured parameter is expected. The accuracy of the friction power losses assessment method is not sufficient for research purposes. However, despite the expected significant errors, assessed parameters trends observation should allow to detect ofrapid changes of machine technical condition caused by piton scuffing. To ensure the sense of this method a precise measurements and in particular the error consistency of indicated pressure assessment of all cylinders in long time period are necessary. The experience from engine-compressors monitoring and diagnostic system services, the main sources of errors and methods for their minimization are described in the paper.

6

Korelacja fluktuacji pracy indykowanej z fluktuacjami prędkości obrotowej wału korbowego i natężenia prądu generowanego w zespole prądotwórczym

Cupiał K., Gruca M., Grzelka J.

Silniki Spalinowe

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2006

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R. 45, nr 2

37-44

PL

W pracy przedstawiono wyniki wstępnych badań korelacji fluktuacji pracy indykowanej z fluktuacjami prędkości obrotowej wału korbowego i natężenia prądu generowanego w zespole prądotwórczym. W przypadku jednocylindrowego agregatu prądotwórczego stwierdzono bardzo wyraźny związek między pracą indykowaną silnika spalinowego a energią elektryczną obliczoną w przedziale czasowym odpowiednio przesuniętym kątowo względem początku cyklu silnika. Praca indykowana kolejnych cykli również dobrze koreluje z przyspieszeniem kątowym wału korbowego w określonej fazie cyklu. Nieco gorsza jest korelacja między amplitudą prądu elektrycznego i pracą indykowaną. Stwierdzono również korelację energii elektrycznej mierzonej w 90 stopniowym oknie kątowym i pracy indykowanej.

EN

The paper presents the results of the introductory investigations of the correlation between the fluctuation of the indicated work and the fluctuation of the crankshaft speed and the electric current from a generating set. A clear relationship between the engine indicated work and the electric energy calculated in the time interval angularly shifted regarding the beginning of the engine cycle was stated in the case of the single-cylinder generating set. The indicated work of the consecutive cycles also well correlates with the crankshaft angular acceleration in the determined cycle phase point. A little worse is the correlation between amplitude of electric current and indicated work. The correlation between electric energy calculated in 90 degree angle interval and indicated work was also stated.