1.1 The scientific purpose of the project
Economic factors, increase in crude oil price and the need for reduction of harmful substances emitted from motor vehicles will bring about in the nearest years, already settled, the wide use of biofuels in the entire world. Research carried out till now indicates that the prevalence of biofuels will probably cause considerable reduction of emissions, which be of benefit to natural environment protection and human health and also to increasing problems with energy balance. Additionally, one should take into consideration the increasing share of vehicles with diesel engine in Europe and in Poland, caused by the rapid development of this type engine design in recent years, their improved efficiency comparing to gasoline engines, and resulting lower operation costs.
However, to verify and make optimal use of qualities of fuels with biocomponents, particularly diesel fuels with FAME, it is necessary to carry out research and testing work with broad scope in order to solve already identified problems related to compatibility of lubricating oil with fuel as well as to determine the impact of biocomponent content in diesel fuel on particulate matter and other harmful components of exhaust gases emissions both in terms of quantity and quality.
For more than a decade, particulate emission has aroused both great interest and anxiety because of its harmful impact on health. Investigation work carried out until now determined already a wide spectrum of threats to health of persons exposed to particulate matter inhalation, although it is known that it would be necessary to conduct even more thorough investigation to fully assess all risks resulting from specified emission. Accurate determination of the biocomponent effects on particulate emissions, considering composition, quality, and consumption of oil used for engine lubrication will create additional problems.
One of the most important problems related to generation and composition, and therefore harmfulness of particulate matter is determination of the impact of engine oil on quality and quantity of detrimental substances in emission. So far it is known that it is oil consumption, particularly quantity and type of applied additives which has significant effect on a particulate matter structure, specifically on its soluble organic part, adsorbed on soot surface. The mass fraction of hydrocarbons of burnt or partly burnt engine oil origin may reach 50% of the particle total mass, depending on engine operating conditions and many other factors. The soluble organic fraction of solid particles, especially aromatics, has a mutagenic and carcinogenic effect, which proves the necessity for further research work, notably because of implementation of biofuels with not fully recognized impact on the above mentioned effect. This work should aim at the most precise determination of the impact of lubricating oil quantity and quality on diesel particulate emission and examination of its substantial reduction by making the most of biofuel characteristics and possibility of selected engine parts governing.
It is believed that generation all kind of sludge in engines as well as suspended and glutinous matter in lubricating oils is caused by adverse interaction between fuel and additive packages applied to high-quality engine oils for modern driving units. Experience acquired in the past years teaches us, however, that the formation of black sludge or deposits in general in engines is always connected with complicated physico-chemical processes and variety of numerous inextricably linked factors. It should be stressed that as of 1996 continually toughened regulations on natural environment protection forced, among other things, significant reduction in sulphur content in diesel fuels (from about 2000 ppm down to <50, even <10 ppm). This considerable reduction in the sulphur level was possible thanks to substantial changes in the production technology of diesel fuels which resulted in changes of their composition (among other things, reduction in oxygenates, nitrogen compounds, and aromatics content), and these, in turn, influenced the change of diesel fuel characteristics. The elimination of sulphur from fuel makes possible the use of advanced exhaust gas aftertreatment systems (oxidation catalysts, catalysts for selective reduction etc.), which previously poisoned by fuel sulphur, readily deteriorated their performance. At the same time it was noticed that burning of diesel fuels with low sulphur content (<10 ppm) contributes (unless a suitable detergent additive is applied) to speeding up of fuel injector fouling and following increase in particulate matter emissions. Further increase in injector fouling could be influenced by engine oil penetration into fuel through multisection injector pumps lubricated by engine oils. Fuel injector clogging could cause further increase in particulate emissions or, because of restriction of fuel flow in combustion chamber, formation and penetration of larger amount of soot and unburned fuel into lubricating oil. The need for nitrogen oxides emission limitation for turn brought about the common use of EGR systems and injection timing retardation effecting a reduction of combustion temperature, but simultaneously contributing to substantial loading of lubricating oil with soot deposited on fuel filters. These phenomena result in fast increase in soot content in lubricating oil leading to increase in its viscosity, rise in a operation temperature, increase in flow resistance and causing difficulties with lubrication of various engine parts. This is particularly disadvantageous during engine cold start-up. In these critical conditions the engine lubrication is retarded because of increase in the oil viscosity. Increase in the oil temperature above the level around 120oC causes formation of so called high-temperature deposit in lubricating oil. Widespread implementation of diesel fuels with biocomponents involves absolute necessity of examination of the impact of the biocomponent type and quantity on the above described adverse phenomena which are certain to pose a threat to correct operation and long service life of an engine.
The scientific purpose of the project is to recognize the mechanism involved in the described above adverse actions of diesel fuel with biocomponents and different sorts of engine oils and to determine the most advantageous composition and physic-chemical properties of the said fuel and oil to limit diesel engine particulate emission both in size and harmfulness.
1.2. The importance of the project
The mentioned needs and factors resulting from the constantly toughened regulations governing the protection of natural environment and human health force the widespread implementation of fuels with biocomponents. This acquires special significance in Poland, which imports almost all quantity of (rapidly increasing in price) crude oil, needed for production of motor fuels. The expected widespread utilization of biofuels must be however preceded by a broad scope examination allowing unequivocal determination of the impact of engines fuelled with these fuels on emission of harmful substances, mainly particulate matter, into atmosphere. Moreover, it is necessary to determine and indicate all potential threats from engines operated with the use of biofuels in connection with their impact on lubricating oils. Execution of the appropriate research will involve necessity of the long-lasting use of an expensive research equipment and engagement of experienced staff, in many cases including experts in given fields. It will be also necessary to use the experience of foreign centers and to utilize their research potential in a part of the planned work.
These reasons prove that the broad scope of the intended cognitive research work, essential for accomplishment of the project purposes is connected with spending large amount of cash. For polish research centers this accomplishment is possible only when partially funded. However, the undertaking of the proposed topic is unavoidable and constitutes the condition of utilization of diesel fuels with biocomponents which is safety, reasonable and not posing any threats. The positive results of the project permit us to broad practical knowledge related to operation of vehicles fuelled by the particular fuel and to avoid many problems connected with the use of these fuels.
When considering the positive aspects of the biofuels use one should stress that:
- Methyl esters of fatty acids (FAME) can be produced from rapeseed, which is popular in Poland and does not contain sulphur, influencing beneficially reduction of emissions
- The biofuel are produced with so called closed carbon dioxide cycle, having considerable lower influence on the greenhouse effect.
- Biofuels of rapeseed origin are biodegradable, so much safer for natural environment than fuels processed from petroleum.
- Processing of rapeseed for fuel production permits manufacturers to create new jobs, which is of great social importance in days of rising unemployment.
- Promulgation of rape crop growing, not being consumer but energy farming, permits effective utilization of wasteland and contaminated soil.
- Development of the biofuels production and widespread implementation can bring increase in employment and improvement of the Polish countryside state of technology.
1.3. The current range of knowledge
The widespread implementation of a new product (that is in this case fuel with biocomponents) is connected every time with the necessity of conducting complex and very broad investigations aimed first at avoidance potential problems resulting from improper use of such a product or appearance of unknown earlier side effects of its utilization. Marketing of a not fully examined product, as it was many times determined in the past, could result in huge losses caused by very rapidly spreading failures related to appearance of unknown earlier detrimental phenomenon, posing a treat to an user. In consequence, from many years, throughout the world have been conducted diversified investigations aimed at determination of good sides of biofuels and the effects of their utilization in motorization. It should be stressed that considering large variety of biofuel types resulting, among other things, from the method and quality level of their production and the type and quantity of FAME used for the production as well as designing-operational factors the knowledge related to biofuels acquired in particular country could not be generalized. Moreover, a research work carried out in the given particular scope takes time and eats up large sums of money, therefore there are still fields of not fully recognized phenomena and impacts; the profound examination of these fields could constitute a great contribution to the development of the said science field. The objectives defined in the project aimed, among other things, at determination of possible appearance of adverse interaction between components of diesel fuels with biocomponents and engine lubricating oils as well as accurate identification of the said fuels impact on emission of harmful substances are examples of not fully recognized or explicitly determined problems; the examination or verification of the problems will bring original contribution to advance of the investigated knowledge. It should be stressed that achievement of the established objects of the work will be of great importance to limitation of serious engine failures, extension of oil change intervals, systemization of operational recommendations and broadening investigation of biofuel impact on natural environment contamination and human health.
The current range of knowledge on merits and flaws of biofuels is in large measure a set of common ideas which needs permanent verification concerning changes in the fuel and lubricant production technology and factors related to engine design, the way of its operation and other reasons typical for the given country.
1. 4. Methodic of the research
The oil and Gas Institute has experience in determination of negative results of mutual interaction between motor gasoline or diesel fuel and engine oil including changing fuel formulations with various additive packages acquired during completion of several works on the particular subject. The basic difference between those works and this project lies in taking now fuels (diesel fuel) with the different content of biocomponents as the research subject but the way of the work planning will be analogous to the earlier works and acquired experience enable us to avoid many mistakes and permit more professional and efficient conducting the whole research procedure.
The critical evaluation of the current state-of-knowledge regarding the source of negative interaction between tested operational fluids and the fluids impact on particulate matter emissions both in terms of quantity and quality facilitates more precise determination of conducted analyses, tests, and investigations aimed at establishment of a relationship between formation of sludge in oil and a way of engine operation as well as cognition of chemical mechanism the sludge formation connected with the composition of fuel and lubricating oil. For the above problems to be solved both traditional physic-chemical analyses of engine fuels and oils, in which scope the Oil and Gas Institute has accumulated very wide, long standing experience, instrumental methods, particularly chromatographic and non-standardized tests and engine simulations will be employed. The Institute is very well prepared for conducting research work related to various tests and investigations of engine fluids using engine test benches, what is proved by its participation in works of many Working Groups of the CEC (Coordinating European Council for the Development of Performance Tests for Transportation Fuels, Lubricants & Other Fluids).
The fluctuation in particulate matter emission from diesel engine may be mainly caused by engine oil consumption and engine oil characteristics and the composition of additive packages in co-operation with diesel fuel with different content of biocomponents. It was already proved that it is engine oil that has greatest impact on emission of particulate matter soluble parts which at the same time determines their toxicity. That is why investigations of the effects of engine oil and biofuels on particulate matter emission acquire supreme significance, especially as many not solved problems still remain.
Taking into account the novel character of the project in the part related to co-operation engine oils with fuels with biocomponents it is difficult to foresee what methods would be the most suitable for recognition, for example, a particulate matter composition considering lack of standardized research methodics in this scope, widely understood capabilities of the Institute and the need for creative approach to this problem. However, this can contribute to force researchers to enhance creativity in the scope of formation, development, and introduction of new investigation methods. The current lack of experience in the range of the project subject does not allow accurate determination of the schedule and the method of the project realization, since it is a current analysis of obtained results and suitability of used research methods (particularly non-standardized) that will decide about it.