Differences in the evolution of combustion in a single cylinder, DI (direct injection) diesel engine fuelled by B20 were observed upon processing of the respective indicator diagrams. Aiming to further investigate the effects of biodiesel on the engine injection and combustion process, the injection characteristics of B0, B20, B40, B60, B80 and B100 were measured at low injection pressure and visualized at low and standard injection pressures. The fuel atomization characteristics were investigated in terms of mean droplet velocity, Sauter mean diameter, droplet velocity and diameter distributions by using a spray visualization system and Laser Doppler Velocimetry. The jet break-up characteristics are mainly influenced by the Weber number, which is lower for biodiesel, mainly due to its higher surface tension. Thus, Sauter mean diameter (SMD) of sprays with biodiesel blended-fuel is higher. Volume mean diameter (VMD) and arithmetic mean diameter (AMD) values also increase with blending ratio. Kinematic viscosity and surface tension become higher as the biodiesel blending ratio increases. The SMD, VMD and AMD of diesel and biodiesel blended fuels decreased with an increase in the axial distance from spray tip. Comparison of estimated fuel burning rates for 60,000 droplets’ samples points to a decrease in mean fuel burning rate for B20 and higher blends.

The results of engine bench tests of a 2.0l common-rail high-pressure injection passenger car diesel engine fuelled by B70 biodiesel blend are compared with the corresponding results of baseline tests with standard EN 590 diesel fuel. Engine performance and carbon monoxide (CO), total hydrocarbon (THC), and nitrogen oxide (NO _x) emissions were measured. Also, indicative particulate sampling was made with a simplified undiluted exhaust sampler. The aim of this study was to understand better how the engine's electronic control unit (ECU) responds to the different fuel qualities. A series of characteristic operation points for engine testing is selected to serve this purpose better. Data acquisition of the engine ECU variables was made through INCA software. Also, additional data acquisition based on external sensors was carried out by means of Labview software. The results enhance understanding of the engine ECU behaviour with the B70 biodiesel blend. Also, they are compared with what is known from the related literature for the behaviour of common-rail diesel engines with biodiesel blends.

This study examined how adding ethanol to diesel fuel affects combustion characteristics, cylinder pressure and NO_x emissions in an AVL engine. The research focused on key engine parameters, including autoignition delay, in-cylinder pressure rise rates, the peaks of the mean in-cylinder temperature and NO_x emissions. Three fuel types were tested: pure diesel (DF) and blends with 10 and 20% ethanol by volume (DF10 and DF20). The results obtained indicate that increasing the ethanol content in diesel fuel significantly affects the combustion process of the fuel mixture, particularly in its early stage, reducing the benefits of the pilot fuel injection. Moreover, it was observed that the combustion of the DF20 mixture leads to a substantially higher pressure increase in the cylinder, exceeding the values recorded for pure diesel fuel by approximately 25%. Furthermore, the study revealed that ethanol addition increases the peaks of the mean in-cylinder temperature, with a recorded difference of up to 60 °C between pure diesel fuel and DF20. Since NO_x formation is highly temperature-dependent, this temperature rise is likely to result in higher NO_x concentration. Additionally, a slight effect of ethanol on increasing the ignition delay angle was observed. This remained minor, and did not exceed approximately 1 CA. These findings highlight the complex relationship between ethanol content in diesel fuel, combustion dynamics, and emissions. They emphasize the need for optimizing the injection process for ethanol–diesel blends to balance the benefits of ethanol addition with potential challenges related to combustion efficiency, engine load and NO_x concentration.

The application of biodiesel blends is known to significantly affect operation of diesel-injection equipment, especially the injectors and fuel pump. This paper summarizes experience on this subject from burning fuel blends with high-percentages of biodiesel (up to 70%) on a common-rail, high-pressure-injection diesel engine and a conventional DI engine. Both engines were unable to start after running for 100 h each and staying shut off for more than two months. In order to understand the wear characteristics of the injector nozzle, pump pistons, and elastomer parts (in the case of the high-pressure pump of the common-rail engine), due to the prolonged operation with high-percentage biodiesel blends, their injectors and pumps parts were examined and compared by performing normal photography and low magnification microscopy. Additionally, the various elastomer parts of the high-pressure fuel pump of the common-rail engine were examined for wear and deterioration. The results are compared with existing literature results from other researchers. The observed deterioration of diesel-injection equipment is caused by use of high-percentage biodiesel blends and subsequent engine shut down.

The results of full-scale regeneration tests with a unit silicon carbide diesel particulate filter installed on a single-cylinder diesel engine are presented. Two sets of transient regeneration experiments, one for each fuel used, with high level of exhaust gas flow rate (normalized per filter volume) and markedly different levels of soot loading were performed. The test fuels were conventional diesel (denoted as B0) and B20 biodiesel blend. The effect of the biodiesel on filter regeneration was further investigated by means of infrared thermography. The main objective was to investigate the catalytic soot ignition and regeneration propagation when the engine is fueled by biodiesel blends. Special focus was on the temperature distribution across the filter channels and the evolution of the regeneration at the central and peripheral part of the filter. The results indicated a faster evolution of the regeneration with lower overall filter wall temperatures with favorable effects on the filter durability, when the engine is fueled by B20.