In this paper, the effects of biodiesel on performance and emission of the current and new-coming regulation cycles, namely the New European Driving Cycle (NEDC) and the Worldwide Harmonized Light Vehicles Test Cycle (WLTC), were investigated by conducting tests on a passenger car, a Euro-5 Ford Fiesta, equipped with a 1.5-L diesel engine. In a two-axle chassis dynamometer test bed, NEDC and WLTC were performed with pure diesel and biodiesel-to-diesel blend (30% biodiesel, 70% diesel in volume). A substantial reduction in CO (34%, 55%), HC (33%, 40%), and particulate number (PN) (22%, 31%) emissions was observed respectively for both the NEDC and WLTC when biodiesel was used. Besides, it was found that the WLTC has higher load and velocity profile compared to the NEDC. Moreover, lower CO, HC, and PN emissions were observed with B30 fuel under WLTC compared to the NEDC. Nevertheless, slightly higher CO₂ and substantially higher NO_x emissions were observed for the WLTC compared to the NEDC.

Optimization studies for the energy management systems of hybrid electric powertrains have critical importance as an effective measure for vehicle manufacturers to reduce greenhouse gas emissions and fuel consumption due to increasingly stringent emission regulations in the automotive industry, strict fuel economy legislation, continuously rising oil prices, and increasing consumer awareness of global warming and environmental pollution. In this study, firstly, the mathematical model of the powertrain and the rule-based energy management system of the vehicle with a power-split hybrid electric vehicle configuration are developed in the Matlab/Simulink environment and verified with real test data from the vehicle dynamometer for the UDDS drive cycle. In this way, a realistic virtual test platform has been developed where the simulation results of the energy management systems based on discrete dynamic programming and Pontryagin’s minimum principle optimization can be used to train the artificial neural network-based energy management algorithms for hybrid electric vehicles. The average fuel consumption in relation to the break specific fuel consumption of the internal combustion engine and the total electrical energy consumption of the battery in relation to the operating efficiency of the electrical machines, obtained by comparing the simulation results at the initial battery charging conditions of the vehicle using different driving cycles, will be analyzed and the advantages of the different energy management techniques used will be evaluated.

The Wankel engine is a rotary type of four-stroke cycle internal combustion engine. The higher specific power output is one of its strong advantages. In Wankel rotary engine, every eccentric shaft revolution corresponds to one four-stroke cycle, whereas conventional reciprocating engine fulfills four-stroke cycle in two crankshaft revolutions. This means the power stroke frequency is twice that of conventional engines. Theoretically, application of two-stroke cycle on Wankel geometry will duplicate the power stroke frequency. In this research, a single-zone thermodynamic model is developed for studying the performance characteristic of a two-stroke Wankel engine. Two different port timings were adapted from the literature. The results revealed that late opening and early closing port geometry (small opening area) with high supercharging pressure has higher performance at low speed range. However, as the rotor speed increases, the open period of the port area becomes insufficient for the gas exchange, which reduces power performance. Early opening and late closing port geometry (large opening area) with supercharging is more suitable in higher speed range. Port timing and area, charging pressure, and speed are the main factors that characterize output performance. These preliminary results show a potential for increasing power density by applying two-stroke cycle of the Wankel engine.

The results of experiments performed by gasoline and natural gas fuels in a single cylinder research engine were evaluated in this study. The main objective of this study is to compare exhaust gas emissions, efficiency, and burn durations for both fuels in stoichiometric and lean mixture. At the same time, cycle to cycle variation in these operating conditions should not exceed an acceptable value. In the ultra-lean mixture, gasoline fuel exceeded this determined limit before Compressed Natural Gas (CNG). Therefore, the reduction in NO was restricted by cyclic variations. In combustion analysis, although the burn duration of the gasoline in stoichiometric conditions was shorter than CNG, this situation reversed in favor of CNG in the ultra-lean mixtures. Contrary to some studies in the literature, the spark advance and ignition delay for CNG were the same or shorter than gasoline in this study. The primary reasons for this change are the high compression ratio and the different combustion chamber geometry. The increase in turbulence intensity has different effects on CNG and gasoline. As a result, it has been observed that NO emissions can meet the limits without a loss of efficiency for this engine operated with CNG under the ultra-lean mixture.