In this paper, the performance and emission characteristics of a diesel engine were investigated with varying ratios of tung oil-based biodiesel blends (B10, B20, and B50) and neat diesel under different operating conditions. The experimental results showed that the addition of biodiesel blends had different effects on engine power and torque depending on the blend ratio. B10 displayed a slight increase in power and torque, which increased by 1.9% and 6.6%. At the same time, B20 and B50 showed declines slightly. The fuel consumption rate increased slightly with an increasing percentage of biodiesel added. In general, all the blends exhibited significantly lower emissions of CO, NO_X, HC, and smoke compared to neat diesel. B10 displayed the most notable reduction of CO emissions, with a 42.86% decrease at medium to high loads. NO_X emissions of tung oil-based biodiesel blends were reduced at all load conditions except for B50. In addition, HC emissions were all reduced, especially for B20, which led to a 27.54% reduction at 50% load. Among all the tested blends, B50 showed the greatest decrease in smoke emissions of 38.05% compared to neat diesel at 2000 rpm. The research concluded that using biodiesel fuels from renewable resources, such as tung oil, presents a promising environmentally friendly alternative fuel option.

In this study, a pre-matching method was developed based on measured performance parameters and theoretical calculations of turbochargers. First, the turbocharger of a natural gas engine was subjected to a comprehensive performance experiment. According to the experimental results, the maximum efficiencies of the turbine and compressor are 70% and 75%, respectively, and the efficiency of the turbine drops sharply from 70% to 56.6% as the pressure ratio increases from 1.25 to 2.4. In this thesis, a specific turbocharger pre-matching software has been developed in conjunction with a database. Three turbines and three compressors were selected from the self-developed database for matching and comparative study using this method. The simulation results showed that the maximum efficiency of turbine #1, #2 and #3 is 71.3%, 72.2% and 72.7%, respectively, and the efficiency of these three turbines is concentrated between 65% and 72.5%. Obviously, the maximum efficiency of the turbine has increased by 1.3–2.7% and the overall efficiency has improved after the pre-matching. Therefore, this developed pre-matching method can reduce time cost, improve work efficiency and engine performance, and is important for the design and development of turbochargers.