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Castor oil is an alternative fuel as a substitute for diesel fuel. The property that approaches diesel fuel makes jatropha oil help reduce fossil fuel dependence. Abundant raw materials and high cetane properties make castor oil widely used as fuel in diesel engines. This study aims to observe the consumption of fuel and soot emissions produced by diesel engines using a mixture of diesel fuel with castor oil content of 30%. Based on the results of experiments that have been carried out, fuel consumption and soot emissions have increased. The highest increase occurred in SJ30 fuel at 25% loading. Low heating value is a major cause of increased consumption and soot emissions.

Due to good combustion properties of hydrogen comparative to diesel fuel, it can be used at the automotive Diesel engine for improvement of the energy performance and for reduction of the pollutants emissions level. The use of small hydrogen quantities which can be produced on the vehicle board represents another advantage. The paper presents some comparative results of the experimental investigations carried on a truck Diesel engine of 10.34 L displacement fuelled with diesel fuel and hydrogen at engine middle loads. The hydrogen was injected in the engine intake manifold at different volume flow rates from 9 L/min to 40 L/min. The general objective of the research is the analysis of the effects of the hydrogen use at the Diesel engines on the energy performance and on the pollutant emissions. The engine energy performance, pollutant emissions level and combustion parameters at the hydrogen Diesel engine fuelled were analysed and compared with diesel fuel operation. The researches established the favourable influences of the hydrogen use on the Diesel engine operating. The obtained results of the experimental investigations highlight the improving of engine performance at fuelling with hydrogen as addition in air.

An extended investigation on the application of blends between diesel oil and used cooking oil methyl esters (UCOME) was developed on an automotive turbocharged diesel engine. Two commercial diesel oils were considered as reference fuels, the first with the conventional content of biodiesel (7%), the second with an amount of 15%. Then, increasing levels of UCOME were added, on a volumetric basis (20%, 40%, 55 or 60%), to analyse the influence of biodiesel content on engine behaviour. Three part load engine operating conditions were selected for tests, measuring average engine parameters and indicated pressure diagrams. Their processing allowed to calculate the most important operating, energy and environmental engine quantities, rate of heat release and related combustion parameters. A proper management of the exhaust gas recirculation circuit, variable nozzle turbine and injection system was applied thanks to the availability of an open electronic control unit. An optimal UCOME content (40%) was identified, leading to highest values of brake thermal efficiency (with maximum increase around 5% referring to baseline fuels) and lowest levels of NOX emissions. For this blend, the analysis of combustion parameters outlined that the use of the renewable fuel corresponded to an enhanced premixed combustion phase, while reducing combustion duration. Lower local temperature levels, related to the decrease of Lower Heating Value, other local effects and biodiesel degree of unsaturation justify NOX reduction. Furthermore, soot emissions were always reduced when increasing biodiesel content, while combustion stability was not affected. All these outcomes were observed with and without EGR.

Effects of initial ambient temperatures on combustion and soot emission characteristics of diesel fuel were investigated through experiment conducted in optical constant volume chamber and simulation using phenomenological soot model. There are four difference initial ambient temperatures adopted in our research: 1000 K, 900 K, 800 K and 700 K. In order to obtain a better prediction of soot behavior, phenomenological soot model was revised to take into account the soot oxidation feedback on soot number density and good agreement was observed in the comparison of soot measurement and prediction. Results indicated that ignition delay prolonged with the decrease of initial ambient temperature. The heat release rate demonstrated the transition from mixing controlled combustion at high ambient temperature to premixed combustion mode at low ambient temperature. At lower ambient temperature, soot formation and oxidation mechanism were both suppressed. But finally soot mass concentration reduced with decreasing initial ambient temperature. Although the drop in ambient temperature did not cool the mean in-cylinder temperature during the combustion, it did shrink the total area of local high equivalence ratio, in which soot usually generated fast. At 700 K initial ambient temperature, soot emissions were almost negligible, which indicates that sootless combustion might be achieved at super low initial temperature operation conditions.

Recently, the stricter diesel emission standards have been setting and an after-treatment of exhaust gas is needed. In this study, as a potential non-catalytic system, the after-treatment using a carbon-fiber filter was investigated, where soot particulates are burned by an electric heater. In the vehicle tests, the experimental validation for our proposed system was conducted, where the soot volume fraction and particle size distribution in diesel exhaust gas were measured. Since the filter was attached to the exhaust pipe, the filter backpressure increased with higher soot emission. Thus, the performance of the filter was evaluated under the same pressure condition. It is confirmed that, the soot emission is greatly reduced by trapping the diesel soot. In addition, the particle number concentration is smaller, so that most of soot particulates are trapped and burned inside the filter. However, in the after-treatment process, particulates less than 30 nm are newly formed. In experiments, the information on the soot oxidation process was limited, and the numerical simulation was performed to investigate temperature field and soot oxidation rate in the filter. It is found that the continuous regeneration is largely promoted by increasing the filter wall temperature. Hence, it is necessary to pay more attention on the effect of filter wall temperature on the particle size for more reduction of smaller particulates.

An interesting alternative to fossil fuel for Diesel engines is the use of Diesel-like oil from plastic wastes: such a solution yields the double advantage of recovering the valuable energy content of wastes, as well as of mitigating the disposal problem of the very large amount of plastic wastes produced by both domestic and industrial activities. The present paper describes the experimental campaign carried out on a current production indirect injection, naturally aspirated diesel engine, running on standard Commercial Diesel Oil (CDO) and on a Waste Plastic Oil (WPO) derived from the pyrolysis of plastics. Tests have been carried out at both full and partial load, while in-cylinder pressure traces have been measured in order to analyze the combustion phase. The results of the experimental campaign showed a slight reduction of engine performance for the WPO, basically due to a lower volumetric fuel rating, but better brake specific fuel consumption and brake fuel conversion efficiency (differences up to 8%). In-cylinder pressure traces, measured at the same load, revealed some difference in the first part of the combustion process, in particular at high speeds, where for WPO heat release is smoother. Engine soot emissions are always lower running on WPO, with difference up to 50% at full load.

To elucidate the relationship between physicochemical properties, spray characteristics, and combustion performance, a series of experiments have been conducted in a constant volume vessel with injection of hydrous ethanol diesel emulsion and regular diesel. HE30 (emulsion with 30% volume fraction of 20% water-containing ethanol and 70% volume fraction of 0# diesel) is developed using Shah’s technique and regular diesel is also employed for comparison. Firstly, the physicochemical properties of two kinds of fuels are investigated. Then, the non-evaporating and evaporating spray characteristics are examined through the high-speed shadowgraphs. Finally, spray combustion experiments under different ambient oxygen concentrations are carried out, and color-ratio pyrometry (CRP) is applied to measure the flame temperature and soot concentration (KL) distributions. The results indicate that the physicochemical properties, such as density, surface tension, kinematic viscosity, cetane number, and oxygen content, have significant impact on the spray mixture formation and combustion performance. HE30 exhibits lower soot emissions than that of regular diesel. Further analysis supports the standpoint that the hydrous ethanol diesel emulsion can suppress the soot and NOx simultaneously. Therefore, the hydrous ethanol diesel emulsion has great potential to be an alternative clean energy resource.

В даній статті розглянуто вплив озонування палива на процес згоряння нафтового дизельного пального та дизельного пального біологічного походження. Проведено теоретичне дослідження озонування дизельного палива. Наведено методику та результати розрахунку температури, вмісту сажі та швидкості її утворення в камері згоряння та у відпрацьованих газах дизеля., В данной статье рассмотрено влияние озонирования топлива на процесс сгорания нефтяного дизельного топлива и дизельного топлива биологического происхождения. Проведено теоретическое исследование озонирования дизельного топлива. Приведена методика и результаты расчета температуры, содержания сажи и скорости ее образования в камере сгорания и в отработанных газах дизеля., In this paper we examine the effect of ozonation on the process of burning petroleum diesel fuel and diesel fuel of biological origin. The analysis of existing research in the field of ozonation of hydrocarbon fuels is conducted.The mechanism of formation of solid particles in the combustion chamber of a diesel engine is developed. A mathematical model describing the formation and soot burning in the combustion chamber of diesel engine is developed.The technique is developed and results of calculation of temperature, solids content and the rate of their formation in the combustion chamber of diesel engine are presented.As a result of work it is established that oxygen that included in the diesel fuel composition of biological origin intensifies the soot burning in the later stages of the combustion mixture, resulting in lower levels of particulate matter in diesel exhaust gases.

In this paper we examine the effect of ozonation on the process of burning petroleum diesel fuel and diesel fuel of biological origin. The analysis of existing research in the field of ozonation of hydrocarbon fuels is conducted. The mechanism of formation of solid particles in the combustion chamber of a diesel engine is developed. A mathematical model describing the formation and soot burning in the combustion chamber of diesel engine is developed. The technique is developed and results of calculation of temperature, solids content and the rate of their formation in the combustion chamber of diesel engine are presented. As a result of work it is established that oxygen that included in the diesel fuel composition of biological origin intensifies the soot burning in the later stages of the combustion mixture, resulting in lower levels of particulate matter in diesel exhaust gases.