A reduction in emissions in transportation is paramount to achieve full compliance with the European Union’s 2050 targets. In this framework, a great boost to the carbon dioxide (CO₂) emission of internal combustion engines fueled by petroleum-derived fuels can be obtained through the adoption of biomass-derived fuels that can be employed in conventional series production engine vehicles. This paper presents the results of an experimental activity on a two-cylinder turbocharged common rail diesel engine, whose main application is for urban mobility, fueled with renewable fuels: Neste MY Renewable Diesel and Eni HVOlution. Aimed at analyzing the potential employment of renewable fuels as drop-in alternative fuels, the engine performance and emissions were investigated under fixed settings of the injection parameters, in the complete range of the engine speed, at the full pedal position. The comparison with the data from tests in which the engine was fueled with fossil diesel highlighted minimal differences in the performance outcomes, while significant differences were observed in the emissions results. In more detail, there were reduced carbon monoxide (CO) emissions (HVO produced using Ecofining™ technology retained better behavior in relation to HVO produced using the NEXBTL™ technology), advantages in hydrocarbon (HC) and nitrogen oxide (NOx) emissions (HVO from NESTE Oil performed better than HVO from ENI), a decrease in the particle mass and number emissions (HVO from Ecofining™ technology was characterized by a lower particle number and court mean diameter in relation to HVO from the NEXBTL™ technology). The results highlight that an optimization of the engine settings based on the specific properties of each fuel could allow us to take full advantage of these fuels in reducing the environmental impact of cars.

The employment of biofuels in blends with diesel oil proved to attain a reduced environmental impact without compromising the engine performance. Among biofuels, waste cooking oil offers the advantages of its reduced raw material cost in comparison with fresh vegetable oil cost; it also eliminates the environmental impacts caused by its disposal. Although a great number of researches has been devoted to biodiesel combustion in engines and pollutant emissions, few studies can be found on light duty diesel engine equipped with up-to-date technologies. This work aims at investigating the impact of waste cooking oil percentage in blends with diesel oil on the performance and emission characteristics of an up-to-date light and compact common rail diesel engine whose main application is in microcars and in urban vehicles. A comprehensive experimental activity was performed in the engine complete operative field. The comparison of the results with those obtained with standard ultralow-sulfur diesel highlighted that the engine performance was quite similar for B20 and diesel oil. B40 suffered for the lower caloric value in regard to diesel. A reduction in CO and HC was obtained with biodiesel blends, along with an increase in NOx. Particulate emissions were also reduced for biodiesel blends; the mean size of particles was smaller as regards diesel oil.

This research examines the feasibility of using waste cooking oil (WCO) as a substitute for traditional diesel fuel in internal combustion engines, with a focus on biodiesel production. The aim of this research is to evaluate the effects of WCO–diesel blends on engine performance, with particular emphasis on critical metrics including brake specific fuel consumption (BSFC) and brake thermal efficiency (BTE). The study utilizes artificial neural networks (ANNs) to model and forecast the performance and emission characteristics of engines operating with different fuel combinations. The study employs a methodology that involves conducting experiments to evaluate the mixtures of waste cooking oil (WCO) and diesel fuel in diesel engines. Furthermore, artificial neural networks (ANNs) are employed to develop models for predicting engine performance. The analysis focuses on critical metrics, including BSFC and BTE, under various operating conditions. This research aims to improve sustainable energy solutions by demonstrating the benefits of alternative fuels and advanced artificial intelligence (AI) prediction models in automotive applications.

An efficient control of the combustion process is required in order to comply with regulations on pollutant emissions from internal combustion engines. Literature presents investigations devoted to explore the potentiality of externally mounted sensor (speed sensor, microphone, and accelerometer) for combustion diagnosis. A relationship exists between the combustion event measured via an in‐cylinder pressure transducer and engine block vibration measured via an accelerometer. Time and frequency domain processing of acquired signals highlighted the correlation between parameters able to characterize the combustion development and features derived from the engine block vibration data. A methodology was developed by the authors that demonstrated to be suitable for real‐time estimation of combustion progress based on engine vibration. A two‐cylinder common rail diesel engine of small displacement was tested; two configurations were investigated, naturally aspirated, and turbocharged. The in‐cylinder pressure and block vibration signals were acquired and processed in time and frequency domains. The vibrational components mainly related to the combustion process were extracted, and indicators of the combustion positioning were computed. The angular positions of start of combustion (SOC) and MFB50 computed via the heat release curve by means of the in‐cylinder pressure measurements were compared to those obtained by means of the accelerometer signal. High correlation coefficients were obtained for the data acquired during the testing of both naturally aspirated and turbocharged configurations in the complete engine operative field.

This study investigates the influence of alternative diesel fuels containing waste cooking oil (WCO) biodiesel on engine performance, combustion efficiency, and exhaust emissions under varying operating conditions. Experimental analysis was carried out for three fuel types – pure diesel, Diesel WCO20, and Diesel WCO40 – by systematically evaluating the effects of load, engine speed (RPM), and air–fuel ratio (λ). The results demonstrated that increasing the biodiesel share significantly improves the combustion quality and reduces harmful emissions. Compared with conventional diesel, WCO20 and WCO40 blends decreased carbon monoxide (CO) emissions by up to 70%, carbon dioxide (CO₂) by 10–15%, and particulate number (PN) by nearly six times. A moderate increase in nitrogen oxides (NOx) was observed for WCO20 due to higher in-cylinder temperatures; however, NOx levels decreased again for WCO40 because of slower combustion and lower temperature peaks. Brake thermal efficiency (BTE) increased by approximately 10%, while brake-specific fuel consumption (BSFC) exhibited a non-linear dependence on biodiesel concentration—initially increasing for WCO20 and later decreasing for WCO40, reaching 254 g/kWh. Statistical tests (Kruskal–Wallis, p < 0.05) confirmed significant differences among fuel types, especially for CO, NO, and PN emissions. Regression and artificial neural network (ANN) modeling (R² up to 0.99) accurately described the relationships between engine parameters and emission behavior. Overall, the 40% WCO blend (WCO40) provided the optimal balance between engine efficiency and emission reduction, proving its potential as a sustainable and environmentally friendly diesel substitute without requiring engine modifications.