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1

The influence of the compression ratio error and the pressure error at the beginning of compression on the heat release characteristic calculated based on indicator diagram marine diesel engine

Witkowski K.

Journal of KONES

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2018

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Vol. 25, No. 1

457--463

EN

In the operational diagnostic of marine engines, the analysis of indicator diagrams is important. In addition to analysing changes in the values of indicated parameters, should be aimed to oriented broader analysis, including the determination on the basis of experimental indicator diagram of heat release characteristics during the combustion process. In the diagnostics of piston engines, including marine engines, special interest arouses to use single-zone model based on indicator diagrams as a source of information. There are calculated heat release characteristics: net heat release (Q) and intensity of heat release (q). The article discusses the impact problem the characteristics of heat release calculated based on experimental indicator diagram various errors – the compression ratio error and the pressure error at the beginning of compression. Based on the results of own research we analysed the impact on the characteristics of heat release the compression ratio error and the pressure error at the beginning of compression. The effect of the errors on the course of characteristics q and Q, to the typical marine medium speed engine Sulzer A25/30 and low speed engine Sulzer RTA 76 shown.

2

Power loss in a combustion engine of a prototype vehicle

Petróci J., Mantič M., Sloboda O.

Diagnostyka

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2017

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Vol. 18, No. 2

59--64

EN

The paper deals with the analysis of power loss involved in an experimental single-cylinder internal combustion engine during its operation. The experimental engine has been developed and built entirely at the University for the purposes of Shell Eco-marathon. A series of experimental measurements was taken to discover the reasons for the issues we had encountered by obtaining output power characteristics and the value of compression pressure regularly at specific intervals. The data we obtained served to diagnose faults and to propose solutions for their elimination.

3

Development of Knitted Materials Selection for Compression Underwear

Cheng Z., Kuzmichev V. E., Adolphe D. C.

Autex Research Journal

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2017

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Vol. 17, no. 2

177--187

EN

The presented research deals with the development of comfortable male underwear taking into account the development of pattern block methods and the analysis of the relationships existing between the compression pressure, the knitted materials properties, and some push-up effects. The main aim of this study is to achieve the technical selection of the materials based on KES-FB evaluations. The ease value has been used as the main index to connect the structural design of underwear, on one hand, and the body sizes, on other hand. A “bodyshell” system for testing the soft tissue of male bodies by FlexiForce sensor has been implemented. The pressures under the shells at six different places on the male body with ease changing have been tested. The collected results including maximum-possible pressure and material tensile indexes measured thanks to KES-FB have been analyzed in order to find the most relevant indexes of the material properties. A mathematical equations based on relationships combining theoretical model with practical application have been established. These equations will be helpful for the consumers and designers to select “the suitable knitting materials for male underwear” and they can be used too in the perspective of parameterization in CAD, in order to improve product developments efficiency.

4

Model of operational changes in the combustion chamber tightness of a diesel engine

Koszałka G.

Eksploatacja i Niezawodność

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2014

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Vol. 16, no. 1

133--139

PL

W artykule przedstawiono wyniki badań szczelności komory spalania silnika o zapłonie samoczynnym w czasie długotrwałej eksploatacji. Badania przeprowadzono na 5 egzemplarzach sześciocylindrowego silnika wykorzystywanego do napędu samochodów ciężarowych. Zmiany szczelności w zakresie przebiegów 0–500 tys. km określono na podstawie wyników pomiarów: spadku ciśnienia z wykorzystaniem próbnika szczelności komory spalania, maksymalnego ciśnienie sprężania w cylindrach oraz natężenia przedmuchów spalin do skrzyni korbowej w różnych warunkach pracy silnika. Wyniki badań poddano analizie statystycznej. Opracowano stochastyczne modele zmian szczelności komory spalania silnika w funkcji przebiegu samochodu. Model opisuje przebieg wartości średniej wybranego parametru diagnostycznego w czasie oraz granic obszaru prawdopodobnych zmian tego parametru. Wyniki badań wykazały, że zarówno prędkość jak i charakter zmian w funkcji czasu eksploatacji były różne dla różnych parametrów. Najmniejszą dynamiką zmian wyróżniało się maksymalne ciśnienie sprężania (spadek o mniej niż 20% w zakresie przebiegów samochodu: 0–500 tys. km), średnią dynamiką – wskaźnik szczelności, a największą – natężenie przedmuchów spalin (3-krotny wzrost przy 2200 obr/min), przy czym dla dwóch pierwszych parametrów szybkość zmian zwiększała się wraz z przebiegiem samochodu, natomiast w przypadku przedmuchów spalin zmiany miały charakter liniowy. Wyznaczono również pola rozproszeń (zmian odchyleń standardowych) dla badanych parametrów diagnostycznych.

EN

The paper presents the results of tightness testing of an internal combustion engine combustion chamber during long-term operation. The tests were conducted on 5 six-cylinder diesel engines used in motor trucks. Changes in tightness for the distance range 0–500,000 km were determined based on the measurement results of the following: pressure drop measured using a cylinder leakdown tester, maximum compression pressure in the cylinders, and the blow-by flow rate at different engine operating conditions. The obtained test results were analyzed statistically. Stochastic models of changes in engine combustion chamber tightness versus distance traveled were developed. Each model describes the time history of the mean value of a selected diagnostic parameter and the limits of probable changes in this parameter. The test results have shown that both the rate and character of changes as a function of engine operation time differed depending on a parameter. The maximum compression pressure was characterized by the lowest dynamics of changes (a decrease by less than 20% for the distance range 0–500,000 km), the cylinder leakage was characterized by a moderate change dynamics, while the blow-by flow rate exhibited the highest dynamics of changes (a threefold increase at 2200 rpm). It should also be mentioned that in the case of the first two parameters, the rate of changes increased with the distance traveled, whereas in the case of the blow-by the observed changes were linear. Also, dispersion fields (i.e. changes in standard deviations) were calculated for the tested diagnostic parameters.

5

Changes in blow-by and compression pressure of a diesel engine during a bench durability test

Koszałka G., Suchecki A.

Combustion Engines

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2013

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R. 52, nr 3

34--39

EN

This paper presents changes in the tightness of a combustion chamber during a 1200-hour bench durability test. The study was conducted on three four-cylinder turbocharged DI diesel engines with a capacity of 1.3 dm3. The changes in the tightness were determined on the basis of the results of periodical measurements of the blow-by flow rate under different conditions of engine operation and measurements of maximum compression pressure in the cylinders. The results showed that the maximum compression pressure remained at the same level during a long period of engine operation, corresponding to a distance of 150 000 km covered by a car. After that period, the pressure started to decrease (after a distance of 200 000 km, it had dropped by 10%). The blow-by flow rate decreased in the initial period of engine operation and then it started to rise linearly at full engine load. The rate of increase depended on engine speed – it was the smallest at low speeds (20% increase in the time range of 100–1200 hours, which corresponded to a distance of 16 000–192 000 km covered by a car – at 1000 rpm), and the highest at 4000 rpm (an increase of 70% in the same time range).

PL

W artykule zaprezentowano wyniki badań zmian szczelności komory spalania podczas 1200-godzinnej stanowiskowej próby trwałościowej. Badania przeprowadzono na trzech egzemplarzach 4-cylindrowego, turbodoładowanego silnika o zapłonie samoczynnym z wtryskiem bezpośrednim i objętości skokowej 1,3 dm3. Zmiany szczelności przestrzeni roboczej silnika ustalone zostały na podstawie okresowych pomiarów natężenia przedmuchów spalin w różnych warunkach pracy silnika oraz pomiarów maksymalnego ciśnienia sprężania w poszczególnych cylindrach. Wyniki badań wskazują, że maksymalne ciśnienie sprężania przez długi okres pracy silnika, odpowiadający 150 tys. km przebiegu samochodu, nie ulega zmniejszeniu. Po tym okresie zaczyna spadać (spadek przy przebiegu 200 tys. km wynosił 10%). Natężenie przedmuchów spalin w pierwszym okresie eksploatacji silnika spada, po czym, przy pełnym obciążeniu silnika, zaczyna liniowo wzrastać, przy czym szybkość wzrostu zależy od prędkości obrotowej silnika – najwolniej przy małych prędkościach (wzrost o 20% przy 1000 obr/min, w zakresie od 100 do 1200 godzin pracy silnika w teście), a najszybciej przy prędkości znamionowej 4000 obr/min (wzrost o 70%).

6

Changes in the tightness of the combustion chamber of an diesel engine during long-term operation

Koszałka G.

Journal of KONES

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2010

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Vol. 17, No. 3

215-222

EN

The paper presents results of research on changes in the tightness of the combustion chamber during long-term operation. The study was conducted on 5 six-cylinder diesel engines with a swept volume of 6.8 dm mounted in medium size trucks. All 5 trucks were used and serviced in similar conditions. The changes in the tightness o f the combustion chamber were determined on the basis of the results of periodical measurements of maximum compression pressure in cylinders, drop of pressure during a cylinder leakage test and blowby rate under different conditions of engine operation. The investigation was carried out in the range of vehicle mileage of 0-450,000 km. The results show ed that in the initial period of engine use (0-40,000 km) the tightness of the combustion chamber improved, after which it gradually deteriorated. For mileages of over 40,000 km, the significance of linear correlations between results of all tightness measurements and mileage were conflrmed and regression lines were determined. Mean rates of changes in the individual tightness parameters differed considerably among one another. Mazimum compression pressure changed the slowest and blowby the fastest together with mileage. Mean value of maximum compression pressure at 440,000 km was only 13% lower than at 40,000 km, whereas blowby rate at full engine loadat 2200 rpm was 125% higher.