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摘要
This paper introduces a general mathematical model for compression ignition internal combustion engines driven by diesel, biodiesel, and/or biogas. The model is written for dynamic and steady state operation and combines principles of classical thermodynamics and heat transfer, with the use of empirical and theoretical correlations for simplicity, in order to quickly assess the potential of new fuel mixtures such as microalgae-derived biodiesel and biogas to feed the compression ignition internal combustion engines. Geometric and operating parameters (e.g., rpm, piston and cylinder diameter, stroke, engine operating temperature, engine compression ratio, and air-to-fuel ratio) are the basis for the model equations, which are capable of calculating the engine mean indicated pressure, indicated power, and indicated torque with respect to crank speed. Friction losses are quantified based on existing empirical correlations for engines with direct fuel injection, so that engine net power and torque are also assessed. The model was adjusted and experimentally validated by direct comparison of the obtained results to previously published experimental data, and engine nominal curves. The simulations show the following: (i) using only biodiesel, the engine power reduces about 1.0%, and the fuel consumption rises about 12.0% with respect to fossil diesel; (ii) using only natural gas, the engine power reduces about 2.0%, and the fuel consumption reduces about 13.0% with respect to fossil diesel; and (iii) fuel mixtures using 50% of biodiesel and/or 50.0% of natural gas produce power values within 1.0% when compared to each other. The obtained numerical results demonstrate that the model is expected to be an important and simple tool for design, control, and optimization of compression ignition engines driven by diesel, biodiesel, and biogas fuel mixtures, due to the combination of accuracy with low computational time.
- 出版日期2016-1
