Application of FMEA method to solve problems of diesel engines fueled with unprocessed rapeseed oil

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1 Iwona Florczak 1, Marek Klimkiewicz 2, Remigiusz Mruk 3, Jacek Słoma 4, Karol Tucki 5, Janusz Wojdalski 6 Warsaw University of Life Sciences Application of FMEA method to solve problems of diesel engines fueled with unprocessed rapeseed oil Introduction The need to power engines with fuels from renewable sources led many centers undertake research into the use of unprocessed rapeseed oil (URO) and its mixtures with the diesel oil (DO) or other combustible liquid substances to power compression ignition engines [1, 5, 8, 9, 10, 16, 17, 18]. Many authors describe the examples of problems with engines fueled in this manner [6, 11, 13, 16]. To respect the limits of toxic gases emission from the engines fueled with rapeseed oil, it requires to use of the systems treating exhaust fumes [3]. The problems to use the rapeseed oil (RO) as fuel to power the engines constructed to use diesel oil arise from large differences between properties of RO and DO. The rapeseed oil compared to the diesel oil is characterized by: higher density, higher viscosity (almost ten times at 20 C), lower cetane number (RO - approx. 39, DO - approx. 50), higher temperatures of distillation curve (about 100 C), higher acidity causing corrosive effects on copper alloys (acidity increases with increasing storage duration [2]), aggressive effects on some seals materials, much higher temperature of Cold Filter Plugging Point, the content of the phosphorus in the form of phospholipids (phosphorus-containing oils during combustion leads to the formation of deposits in the combustion chamber) and vulnerability to oxidation and bacteriological contamination. The positive characteristics of rapeseed oil are: low sulfur content, the content of about 10-12% of the oxygen in the molecule, good lubricity - providing durability of working parts of fuel equipment, high flash point (above 220 C) to ensure fire protection and above all that it is a fuel from renewable sources. Conducting research on adaptation of diesel engines to power URO [10] was used Failure Mode and Effects Analysis FMEA, which is particularly recommended during the introduction of new facilities or when an object is subject to exploitation particularly in difficult conditions. The FMEA is an inductive method of qualitative analysis of reliability of the system performed from low to high level [14]. The FMEA is a systematic and comprehensive detection of failures, errors and threats. This allows a better understanding of the behavior of the analyzed system. Based on the analysis of the results amendments are introduced or alternatives are used to eliminate the disadvantages. It also helps to determine the sequence of actions to improve the process. The method was applied first in the analysis of failures in the defense industry in the USA and now is used in many industries, including the automotive [4]. The benefit, which the method brought in the implementation of the NASA's Apollo program, resulted in the rapid popularization and expansion of this method to other areas [12, 15]. The final 1 MSc. Eng., I. Florczak, PhD student Department of Production Management and Engineering, Faculty of Production Engineering, 2 Assoc. Prof. M. Klimkiewicz, PhD Department of Production Management and Engineering, Faculty of Production Engineering, 3 PhD Eng. R. Mruk, assistant professor Department of Production Management and Engineering, Faculty of Production Engineering, 4 PhD Eng. Jacek Słoma, assistant professor Department of Production Management and Engineering, Faculty of Production Engineering, 5 PhD Eng. Karol Tucki, assistant professor Department of Production Management and Engineering, Faculty of Production Engineering, 6 Prof. Janusz Wojdalski, D. Sc. Department of Production Management and Engineering, Faculty of Production Engineering, 56

2 FMEA result depends on planning and implementation of corrective actions for failures and events at greatest risk. You can also create a matrix of damages and their effects on other components. The analysis of such matrix allows to determine the effects of damage depends on the structure of the system [7]. The work on the FMEA analysis can be carried out in six steps: 1. Planning and preparation. In this step it is needed to define the system and its basic functions, requirements, boundaries and system environment. 2. Identification of the potential failure modes, potential causes and potential effects (consequences) of failures. The results are collected in the FMEA worksheet. It should be started by specification existing and potentially possible failures. Then are determined the effects of failures in the system or process, for the internal or external customer. 3. Determination of the means of detection failure mode. In this step available research and control measures are evaluated. 4. Three factors affecting the formation of failures: occurrence O, severity S and detection D are defined numerically by giving them rating in the range The Risk Priority Number RPN associated with the related hazard of failure is calculated by multiplying the values of rating of the mentioned factors RO, RS, RD. RPN=RO RS RD (1) 5. Implementation of corrective and preventive actions. Actions are aimed at reducing the risk associated with the failure to an acceptable level. 6. The Risk Priority Number assessment after the introduction of corrective and preventive actions. If the Risk Priority Number is reduced to an acceptable level follows completion of FMEA or the next step could be to establish a new level of acceptable risk and to take further action on its reduction. Analysis The method was applied to the analysis of the drive unit of the tractor or vehicle powered with rapeseed oil. Potential damage and undesirable events were identified on the basis of studies carried out on engines fueled with rapeseed oil on the bench and operational conditions and based on the data given in service of fuel equipment and data from the literature. Distinguished 20 potential failure or undesirable events: 7. Failure of electronically controlled injection pump, 8. Reduced power of electronically controlled engine, 9. Failure of electric fuel feed pump, 10. Immobilization cooperating precision fuel system components as a result of polymerization of oil molecules, 11. Increased wear of I piston ring, strong recesses in the sleeve at the level I and II of the piston ring and piston covered with deposits of carbon, 12. The content of URO in the engine oil, 13. Mechanical damage of the fuel system components, 14. Seizing up of fuel system components due to the harmful effects of water contained in URO, 15. Deformation of flexible seals of the fuel system, 16. Blocking filter by a gel-like substance, which is accompanied by decrease of the engine power (usually after a long stop of the engine), 17. The corrosion inside the tank, 18. The formation of deposits at the nozzle of the injector and the walls of the combustion chamber, 19. Blocking fuel filters at low temperatures, 20. Overheating of the elements on which are deposited the products of combustion, 21. Throttling delivery URO to the heater, 22. The increase of viscosity of the engine oil, 23. Too much particulate matter (PM) and harmful gases in the exhaust, 24. The products of combustion at the nozzle of the injectors and inside the combustion chamber, 25. The corrosion of engine components, 26. Blocking the filter, sediments and sludge in the supply system. 57

3 Then determined the potential impact of undesirable events and their causes in order to introduce corrective measures. For each failure the means of detection were proposed. In the next step, the factors affecting the risk of failures: occurrence, severity and detection were rated and the Risk Priority Number was calculated. The entire analysis was performed in the FMEA worksheet. In Table 1, due to the size of the paper is presented an analysis of only three selected potential undesirable events. Table 1. Analysis by the FMEA method failures of engine fueled with rapeseed oil Potential efects of failure Potential cause of failure The present state The means RO RS RD RPN of detection The state after recommended action The action RO RS RD RPN taken Engine cannot start after a longer standstill (over 4 weeks) The fuel system was not flushed after a longer standetectondstill Organoleptically Two tank system has been proposed Leaks in the fuel system Sealing material is not resistant to the URO Organoleptically No action is taken Bacteriological contamination of the URO Leaking of the tank, fuel contamination Organoleptically Biocide Grotamar 71 has been applied Source: Own resarch The greatest Risk Priority Number characterized the problem of "Too much particulate matter (PM) and harmful gases in the exhaust". This problem can be solved by the application of modern electronically controlled fuel systems and equip the engine in exhaust aftertreatment systems. After the recommended actions are taken the number of priority risks can be reduced from 500 to 50. A serious problem can be "Increased wear of I piston ring, strong recesses in the sleeve at the level I and II of the piston ring and piston covered with deposits of carbon". The Risk Priority Number for this failure is 430. Then, in the case of working in such conditions conducive to wearing e.g. using long-term idling should switch to fuel with diesel oil. The Risk Priority Number can then be reduced to 48. The main problem that occurs during the use of unprocessed rapeseed oil to power diesel engines is the "Formation of deposits on nozzles of the injectors and combustion chamber walls". The Risk Priority Number for this problem is 256. This problem can be solved by the use of oil additives containing substances that improve the catalytic combustion of oil and detergents to facilitate cleaning of the surface of the carbon deposits, for example, Platinum Plus DFX. In this way, the Risk Priority Number can then be reduced to 48. The problem of "Blocking fuel filters" (the Risk Priority Number - 180) can be solved by the use of heating fuel to a temperature above 60 C and power the engine at low temperatures with diesel oil (The Risk Priority Number - 18). "The increased viscosity of engine oil" (the Risk Priority Number - 144) can be prevented by twice more frequent exchange of engine oil than is done when the engine is powered with diesel oil. In this case also proposed comparative viscosity control method with the reference oil. In this way both rating factors were reduced: occurrence and detection, and thus reduced the Risk Priority Number to 4. Immobilization cooperating precision fuel system components as a result of polymerization of oil molecules (the Risk Priority Number - 126) can be prevented by application of a two-tank system and flushing the fuel equipment by power the engine with diesel oil for two minutes before the end of the work (the Risk Priority Number - 42). 58

4 Overheating elements on which was formed the carbon deposit (the Risk Priority Number - 125) can be prevented by the addition of rapeseed oil additive - Deutz Clean Diesel InSyPro or Platinum Plus DFX (the Risk Priority Number - 35). In a similar way, by improving the combustion process using an additive to the fuel can be prevented "URO content in the engine oil. This reduces the Risk Priority Number from 112 to 56. Summary As a result of the FMEA method and taking preventive measures have managed to reduce the Risk Priority Number of undesirable events to an acceptable level. The corrective action, which solved many of the problems simultaneously is to use a two-tank system with the possibility to supply the engine during the cold start with diesel oil, and when the engine warm-up switching it to power heated rapeseed oil, which reached a sufficiently low viscosity. Good results can provide fuel heating and the use of the water separator. Many problems can be avoided by the use of an additive for improving combustion of rapeseed oil. Implementation of the remaining recommended corrective action will support trouble-free operation of diesel engine with rapeseed oil. Abstract In this paper the authors have presented the method of FMEA to assess the failures of engines fueled with unprocessed rapeseed oil. On the basis of studies carried out on engines fueled with rapeseed oil on the bench and in operating conditions, and based on data from the service of fuel equipment are specified 20 potential failures and undesirable events, defined their potential causes and effects, and determined the number of priority risks. For events with a large of Risk Priority Number introducing corrective measures were proposed. ZASTOSOWANIE METODY FMEA DO ROZWIĄZANIA PROBLEMÓW Z ZASILANIEM SILNIKÓW WYSOKOPRĘŻNYCH NIEPRZETWORZONYM OLEJEM RZEPAKOWYM Streszczenie W artykule autorzy przedstawili zastosowanie metody FMEA do oceny uszkadzalności silników zasilanych nieprzetworzonym olejem rzepakowym. Na podstawie badań przeprowadzonych na silnikach zasilanych olejem rzepakowym na stanowisku badawczym i w warunkach eksploatacyjnych oraz opierając się na danych z serwisu aparatury paliwowej wyszczególniono 20 potencjalnych uszkodzeń i zdarzeń niepożądanych, określono ich potencjalne przyczyny i skutki oraz określono liczby priorytetowe ryzyka. Dla zdarzeń o dużej liczbie priorytetowej ryzyka zaproponowano wprowadzenie działań naprawczych. Bibliography [1] Ambrozik A., Kurczyński D.: Ocena porównawcza charakterystyk obciążeniowych silnika o zapłonie samoczynnym zasilanego olejem napędowym, paliwem roślinnym i ich mieszaniną. MOTROL, 8A, 21-30/2006. [2] Cieślikowski B., Ślipek Z.: Zmienność cech oleju rzepakowego w warunkach przechowywania. Inżynieria Rolnicza. Nr 13 (88)/2006, s [3] Cieślikowski B.: Kierunki badań i najnowsze trendy rozwojowe w konstrukcji ciągników rolniczych. Ekspertyza. /2011. [4] Dhillon B.S.: Design reliability. Fundamentals and Applications. London, New York, Washington, CRC Press Boca Rato, [5] Dzieniszewski G.: Analiza możliwości zasilania silnika Diesla surowym olejem rzepakowym. Inżynieria Rolnicza, 12(87)/2006, [6] Dzieniszewski, G.: Wybrane problemy stosowania biopaliw do zasilania silników z zapłonem samoczynnym. Inżynieria Rolnicza, 10(108)/2008,

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