Self-ignition Engines Research Articles

Fuel System Contamination Affecting Injection Equipment of Diesel Engines

This article describes selected contaminants of the fuel system which substantially affect the operation of fuel injection equipment of self-ignition engines. The authors present a simple method of identifying biological contaminants (bacteria and fungi), which can be used with no need for laboratory tests during a vessel’s voyage at sea.

RESEARCH OF WATER-FUEL MICROEMULSIONS AS FUEL FOR DIESEL ENGINE

The combustion of fuels is and will be in the nearest future a basic way of acquiring the energy, among others, for transport purposes. Transport causes many threats for natural environment. It produces powders and particulates, together with many gaseous noxious substances and is also the source of noise and vibrations. Sources of propulsion, applied in transport, are almost exclusively piston-combustion engines, among which the dominant role play self-ignition engines. In the light of well-known advantages of these engines, they were accepted as most beneficial sources of car vehicles’ propulsion in nearest decades, provided they meet the requirements of the future legal regulations regarding the environmental protection. The emission of nitrogen oxides (NOx) and particulate matters (PM) is a problem to be solved in modern engines. This constitutes so called targets conflict, consisting in excluding the alternative of both coefficients’ decrease, in the way of regulation the set of an engine and the limiting emissions, permitted by the EURO regulations. From among many different methods of limiting both the formation and emission of NOx, the method of the selective catalytic reduction (SCR) is universally applied. This method requires special installation with the catalyst and the reservoir intended for the „clinically” clean reductive measure. In the aspect of constituting opinions regarding the need of reducing additional installations and media on board the vehicle, it seems that to supply the engine with fuel-water emulsion and especially fuel-water microemulsion becomes an interesting solution.

Application of Alcohols to Dual - Fuel Feeding the Spark-Ignition and Self-Ignition Engines

Abstract This paper concerns analysis of possible use of alcohols for the feeding of self - ignition and spark-ignition engines operating in a dual- fuel mode, i.e. simultaneously combusting alcohol and diesel oil or alcohol and petrol. Issues associated with the requirements for application of bio-fuels were presented with taking into account National Index Targets, bio-ethanol production methods and dynamics of its production worldwide and in Poland. Te considerations are illustrated by results of the tests on spark- ignition and self- ignition engines fed with two fuels: petrol and methanol or diesel oil and methanol, respectively. Te tests were carried out on a 1100 MPI Fiat four- cylinder engine with multi-point injection and a prototype collector fitted with additional injectors in each cylinder. Te other tested engine was a SW 680 six- cylinder direct- injection diesel engine. Influence of a methanol addition on basic operational parameters of the engines and exhaust gas toxicity were analyzed. Te tests showed a favourable influence of methanol on combustion process of traditional fuels and on some operational parameters of engines. An addition of methanol resulted in a distinct rise of total efficiency of both types of engines at maintained output parameters (maximum power and torque). In the same time a radical drop in content of hydrocarbons and nitrogen oxides in exhaust gas was observed at high shares of methanol in feeding dose of ZI (petrol) engine, and 2-3 fold lower smokiness in case of ZS (diesel) engine. Among unfavourable phenomena, a rather insignificant rise of CO and NOx content for ZI engine, and THC and NOx - for ZS engine, should be numbered. It requires to carry out further research on optimum control parameters of the engines. Conclusions drawn from this work may be used for implementation of bio-fuels to feeding the combustion engines.

Analyses of the Causes of Common Rail Piezoelectric and Electromagnetic Injectors' Premature Destruction in Self-Ignition Engines

In self-ignition engines with Common Rail direct fuel injection, premature destruction of injectors has been observed. New elements are also touched by the problem. In order to solve it, a group of international experts in the area have gathered. Destroyed piezoelectric and electromagnetic injectors' elements of BOSCH, DELPHI, DENSO, have been examined. Mechanical damages influencing electronic diagnostic signal have been presented. Some system solutions possible to perform as far as diagnostic prevention is concerned have been described. Some useful electronic diagnostic methods of fuel system, signal analysers: RMOG and ERDIA PRO, have been presented.

A correlation analysis of the pollutant emission from a self ignition engine

This paper presents the results of studies on pollution emissions from self-ignition engines. The studies were conducted on a Citroen Berlingo delivery van on a chassis test bed applying the ECE R 83 test with start-up of a warm engine. Pollutant emission intensity was registered in a continuous manner. The registered runs of pollutant emission intensity were subjected to digital processing. A correlation analysis was conducted subsequently. The Pearson, Spearman, Kendall, and Kruskal theories were applied in the study. The analysis demonstrated a clear correlation between the examined runs. The probability of non-rejection of the hypothesis regarding the lack of correlation was equal to zero with an accuracy of at least six places beyond the decimal point. An exception was the correlation test between carbon monoxide and carbon dioxide emission intensity processes for which the probability of non-rejection of the hypothesis regarding the lack of correlation amounted to a maximum of approximately 5%.

Operational problems of large power diesel engines combusting biofuels, considered together with assessment of their operation

Operational problems of large power diesel engines combusting biofuels, considered together with assessment of their operationIn this paper the problem is discussed of supplying high power diesel engines with biofuels in the aspect of consequences which occurr during their operation. Attention was paid to advantages and difficulties associated with application of biofuels to self-ignition engines. A relevant research problem was characterized and research targets were proposed to make it possible to most favourably shape energy merits of the engines. Special attention was given to wear process of such engines and their failures resulting from application of biofuels. The following problems were also considered: calcium carbonate sedimentation, closing graphite platelets in structure of cylider bearing surface and surface defects of piston rings made of aluminium bronze. It was demonstrated that to assess operation of the engines is possible under the assumption that in a valuating approach their operation can be compared to a physical quantity represented numerically and measured with the use of the joule*sec unit. Conclusions resulting from the domestic and foreign investigations on power and reliability of such engines were also presented.

The use of turbulization in preliminary fuel treatment in self-ignition engines

It is possible to increase the effectiveness parameters of self-ignition engine performance as well as to decrease the emission of toxic compounds in exhaust gases by using preliminary catalytic fuel treatment - PROCESSING – executed directly in the injector body. In order to enhance the impact of the catalyst on the flowing fuel we propose to take advantage of the phenomenon of turbulization in injector passages. First results of tests on an engine of 359 type have shown an improvement of operating parameters and a decrease of toxic emission in exhaust gases.

Physical aspects of wear of the piston-ring—cylinder set of combustion engines

The research presented in this paper has shown that the physical aspects of interfacial phenomena, described by the total value of surface free energy and the values of its components, make it possible to select more suitable materials for sliding pairs. The total value of surface free energy depends on the molecular structure and the bonds characteristic of a given material, and determines its hardness. In order to reduce friction losses in a sliding pair that is being designed, it is proposed to match such materials for the pair in such a way that the surface of one of them has a high sum of surface free energy components originating from van der Waals interactions, while the other material's surface has a possibly low value of the sum. Furthermore, proper values of the components of surface free energy ensure proper wettability with lubricating oil. In order to minimize friction in a sliding contact, the element with the larger surface area (e.g. a cylinder sleeve) should have larger dispersion and van der Waals forces compared with those of the oil, while the element with the smaller area (e.g. a piston ring) has to have smaller (as low as possible) dispersion and van der Waals forces compared with those of the lubricating oil. Thus a basis for reducing friction losses, particularly during mixed friction and boundary friction, has been created. Pursuing the practical goal of this research, a new cylinder liner sliding pair of a piston-ring—cylinder (PRC) set (in which the ring has a titanium nitride (TiN) coating and the cylinder liner has a surface layer with varying properties, applied by vacuum nitriding) of a piston packing ring—combustion engine was designed and made. The sliding pair can be used in self-ignition combustion engines and in spark-ignition engines. The sliding pair is the result of the research carried out as part of this paper, including tests in a tribotester and three-stage testing embracing numerical simulations, preliminary tests on the real object, and tests proper on the real object.

A probabilistic concept of load assessment of self-ignition engines

A probabilistic concept of load assessment of self-ignition engines A proposal of probabilistic interpretation of loading process of self-ignition combustion engines, was presented. Probabilistic description of loading the engines was proposed with taking into account known parameters (indices) of their operation. It was demonstrated that instantaneous load of such engines can be considered a random variable. Attention was paid to the fact that the load can be taken as a multi-dimensional random variable. Engine load changes during its operation were considered as the loading process and presented in the form of a multi-dimensional stochastic process whose states are loads considered to be random variables. It was demonstrated that the loading process can be taken as the stochastic one of asymptotically independent incements, stationary and ergodic. Justification of the above mentioned features of the loading process is contained in the presented hypotheses. It was also demonstrated that in testing the load process of self-ignition engines stochastic relation between thermal and mechanical loading should be taken into account.

The electro-hydraulic valvetrain system

The electro-hydraulic valvetrain system (EHVS) is one of the most flexible options for replacing the conventional mechanical camshaft by an electronically controlled actuator system. Thus, fully variable feeding and dissipation of the gases involved in the combustion process can be ensured. The EHVS provides high potential in view of the optimisation of fuel consumption, torque characteristics and emissions for conventional or even turbocharged gasoline and Diesel engines. This system also opens up completely new possibilities for varying the gas exchange of combustion engines. The scope of application includes self-ignition engines with homogeneous gasoline or Diesel mixture. An article from the AVL List GmbH and the Robert Bosch GmbH.