Wyniki wyszukiwania - BazTech

1

Modyfikacja układu do pomiaru przebiegu ciśnienia spalania okrętowego silnika tłokowego Sulzer AL25/30

Wysocki J.

Zeszyty Naukowe Akademii Morskiej w Gdyni

|

2018

|

nr 108

168--180

PL

Artykuł przedstawia wybrane problemy analizy przebiegów ciśnień cylindrowych w okrętowych silnikach tłokowych. Prawidłowo sporządzony i przeanalizowany wykres indykatorowy pomaga w formułowaniu wniosków diagnostycznych, za pomocą których można doprowadzić do optymalnej, pod kątem ekonomicznym i ekologicznym, regulacji silnika okrętowego. Pomiary ciśnień cylindrowych zaliczane są do trudnych, a także obarczonych wieloma błędami, dlatego też głównym tematem artykułu jest przedstawienie nowej koncepcji pomiarów przebiegów ciśnień cylindrowych.

EN

The article presents selected problems regarding the correct analysis of cylinder pressures in ship piston engines. Correctly prepared and the analyzed indicator diagram helps in formulating appropriate diagnostic conclusions, with the help of which it is possible to achieve the optimal, in economic and environmental terms, regulation of the ship's engine. Cylinder pressure measurements are classified as difficult and also burdened with many errors. Therefore, the main topic of the article is to present a new concept for cylinder pressure measurements.

2

The influence of non-cooled exhaust gas recirculation on the indicator diagrams and heat release parameters in diesel engine cylinder

Cisek J.

Combustion Engines

|

2017

|

R. 56, nr 4

283--288

EN

This paper presents the results of the diesel engine research on the indicator and heat realized diagrams for VW 1.9 TDI working in 2 modes: with standard, non-cooled EGR system, and without this system. All of measurement was carried out on the some engine speed – 2000 rpm (speed of maximum engine torque) and various engine load. Some of the analyzed parameters were read directly from the measurement systems (e.g. indicator diagrams) or engine controller (e.g. start of injection) and the rest of them had to be calculated. The calculation of rate of heat release (δQ/dα) was based on the well-known mathematical model. When the exhaust gas recirculation valve is open, the maximum of combustion pressure and rate of maximum kinetic heat release (δQk/dα)max are smaller than when the valve is closed. These facts are connected with the shorter self-combustion delay for engine working with EGR. But this is also associated with reduction of the rate of maximum diffusion heat release (δQd/dα)max, which means that more particulates (PM) are excreted into the atmosphere. This fact explains e.g. significantly higher smog of exhaust gases for diesel engine which works with EGR system. The analysis results show that exhaust gas recirculation system slightly deteriorates the energetic parameters of VW 1.9 TDI engine, but, at the same time, significantly reduces the level of toxic nitrogen oxides in exhaust gases.

3

Analysing applicability of selected methods to smooth indicator diagrams of marine medium-speed engine

Pawletko R.

Polish Maritime Research

|

2015

|

nr 2

55--61

EN

The article analyses the applicability of selected smoothing methods to smooth indicator diagram curves and to filter disturbances. An intermediate goal of the study was an attempt to extract disturbances recorded during pressure curve smoothing, which are believed to be a source of important diagnostic information. Within the framework of the reported analysis, a comparison was made between the moving average method, the Savitzky-Golay filter, and the frequency filtration method. The research was performed on a marine medium-speed engine Sulzer 3Al 25/30, which has a relatively long indicator passage.

4

Influence of the indicator diagrams smoothing on the indicated parameters of marine diesel engines

Pawletko R.

Journal of KONES

|

2015

|

Vol. 22, No. 2

169--176

EN

The topic of this article is to analyze the influence of indicator diagrams smoothing methods on diagnostic parameters determined on their basis such as the maximum combustion pressure, mean indication pressure and heat release characteristics. Indicator diagrams of marine engines are subject to serious distortions arising primarily from the measuring method for in-cylinder pressure. Measurements are performed on the indicator valve which connect with the combustion chamber through the indicator channel. Depending on the engine design the channel length can reach a considerable length and introduces significant distortion in both the phase and amplitude of the pressure signal. Further analysis of the indicator diagram eg. in order to determine the heat release characteristics requires the use of methods of smoothing and filtering of interference. The results confirm no effect of indicator diagram smoothing for the value of the mean indicated pressure, which is one for the most important indicated parameters. A significant influence of smoothing on the maximum value of the heat release rate was observed. The differences in this case exceed 50%. At the same time confirmed that the heat release rate curve determined on the basis of a diagram without smoothing, carry a high level of interference, which precludes their practical use. Smoothing allows getting heat release rate curves that carry vital information about the working process of the engine.

5

Comparison of indicator and heat release graphs for vw 1.9 tdi engine supplied diesel fuel and rapeseed methyl esters (RME)

Cisek J.

Journal of KONES

|

2013

|

Vol. 20, No. 4

71--78

EN

The results of investigation of 1,9 TDI engine (285 Nm, 85 kW, type AJM without any modification) equipped with injection units supplied conventional diesel fuel (ON) or B100 fuel (RME) have been presented in article. Investigations have been realized at the engine speed of 2000 rpm and variable load within the range of 0 to 275 Nm. The pressure, temperature and heat release velocity runs have been subjected to analysis. Particular attention has been paid to the release of the heat used for the effective work and internal energy increase of the working medium (enthalpy) during combustion inside the engine cylinder versus the crank angle for both investigated fuels. It was found among the others that mentioned fuels differ in the heat release, heat velocity and the maximal combustion temperature, which for the B100 fuel is bigger than for the conventional diesel fuel. Bigger combustion dynamics of tested biofuel (compared with standard diesel fuel) results higher concentrations of Nitrogen Oxides NOx in exhaust gases. The easiest way is of course the use of the later start of fuel injection biofuels and/or increase the exhaust gas recirculation EGR. These treatments, however, result in a worsening of the energy performance of the engine. It was concluded also that the combustion of RME works properly at higher engine loads. Then reduce the negative difference between the combustion of biofuel (RME) and standard Diesel fuel.

6

Problems of determining mean indicator pressure of piston combustion engines from developed indicator diagrams

Monieta J.

Journal of KONES

|

2010

|

Vol. 17, No. 3

301-306

EN

The paper presents methods for processing and analysis of in-cylinder pressure course in the combustion chamber of marine engines. In literature are described determinate methods ofmean indicator pressure from closed diagrams, with are but rarely recorded than developed diagrams. There have been showed on limitations occurrence at measurements fast-changed pressures of marine diesel engines in operating conditions and measuring errors the attendants. Mean indicated pressure determined from the indicated timing or angular pressure courses in the cylinders is still a reliable diagnostic symptom. The paper presents too the results of experimental measurement of in-cylinder pressure signals, medium speed marine engines with application resistive sensor and using the photo-optical sensor of crankshaft position, and without the marker position of the crankshaft. Not always possible to altach the marker for the position of the crankshaft, and even there is no way of stopping the engine when you need to diagnose it. The top dead centre of the piston can be determined then analytically. The work developed a method of determining the mean indicated pressure of the developed indicator diagrams. Based on calculations ofmean indicator pressure made many of diagnosis of the medium speed marine diesel engines in the operating conditions.

7

Wielkości i parametry diagnostyczne procesu spalania w silniku o zapłonie samoczynnym

Ambrozik T., Łagowski P.

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

|

2009

|

z. 1/73

5-15

PL

W artykule przedstawiono metodykę aproksymacji rzeczywistych wykresów indykatorowych z wykorzystaniem funkcji sklejanych, opisujących postać tych wykresów w sposób analityczny zapewniając otrzymanie parametrów diagnostycznych procesu w postaci wartości współczynników funkcji sklejanych oraz gładkich charakterystyk wydzielania ciepła. Wartości współczynników funkcji aproksymujacych mogą być także wykorzystane jako parametry sterujace przebiegiem procesów zachodzących wewnątrz cylindra tłokowego silnika spalinowego. W pracy przedstawiono także metodykę regresji liniowej wyznaczania współczynnika politropy sprężania i politropy rozprężania na podstawie sporządzonych wykresów indykatoowych w podwójnej skali logarytnicznej . Ponadto metodyka pozwala na wyznaczenie punktu początku procesu spalania jako oderwanie wykresu od linii prostej aproksymującej politrope sprężania jak również końca procesu spalania jako analogiczne oderwanie wykresu od prostej aproksymujacej politropę sprężania.

EN

The paper the methodology of approximation indicator diagrams using glued functions which describe a form of the diagrams in an analytical way and secure receiving diagnostic parameter of the process in the form of the value of coefficients glued functions and smooth characteristics of the heat emission. The value of coefficient approximating functions can be also used as parameters controlling a progress of processes which happen inside a piston cylinder engine. In the article there was also discussed the methodology of linear regression of determining polytropic compression factor and polytropic expansion factor on the basis of drawn up indcator diagrams in dual logarithmic scale. Moreover, the methodology allows marking the point of the beginning combustion process as the end f combustion process as analogous the separation of the graph from straight line approximating polytropic expansion.

8

Assessing diagnostic applicability of heat release characteristics determined based on ship engine indicator diagrams

Polanowski S.

Polish Maritime Research

|

2009

|

nr 3

32-35

EN

In order to determine indicator diagrams-based heat release characteristics, a single- zone model of net heat release was used for perfect gas. It was proved that when a constant value for isentropic exponent is assumed, the error in determining the characteristics can be limited to 1% at the nominal load. The effect of errors in determining the position of piston TDC, as well as that of gas passages and indicator valves on the calculated characteristics was evaluated. It was shown that for low-speed engines the effect of gas passages in negligible, while for medium-speed engines the characteristics reveal some deformations (waves), which are repeatable for an individual cylinder in the examined engine construction. The results of the performed investigations and analyses suggest possibility and advisability of the use of heat release characteristics in diagnosing ship engines, in particular low-speed machines.