# Equivalent Simulation Study of Delta-Rotor Engine
## 5 Conclusions  
To address the problem of directly simulating the entire machine performance of a triangular rotor engine through simulation software, in this study, the mechanical structure, motion mode, and combustion process of the triangular rotor engine were investigated,  
Figure 15: Comparison of cylinder pressure and temperature at 7000 r/min. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Crank Speed** & \multicolumn{2}{c}{**7500 r/min**} & \multicolumn{2}{c}{**7000 r/min**} \\ \hline
**Index** & **Cylinder Pressure** & **Cylinder Temperature** & **Cylinder Pressure** & **Cylinder Temperature** \\ \hline Maximum relative error & 9.4687\% & 10.2456\% & 9.8495\% & 10.0643\% \\ Average relative error & 5.6325\% & 2.8594\% & 5.8749\% & 3.1859\% \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Deviation in the range of \(-\)35 \({}^{\circ}\)CA to 135 \({}^{\circ}\)CA at different speeds. and its motion mode and combustion process were equated using GT-SUITE to establish an equivalent one-dimensional simulation model. The key indicators of the triangular rotor engine, such as cylinder volume, cylinder temperature, cylinder pressure, and cylinder quality, were compared. The main conclusions of this study are as follows:  
1. To equate the motion mode of the triangular rotor engine, this study used a genetic algorithm to simultaneously equate the changes in the cylinder volume and cylinder surface area during the motion of the triangular rotor engine. To ensure that the cylinder volume change of the equivalent four-stroke engine was consistent with that of the triangular rotor engine, the change in the surface area of the cylinder was considered similar to that of the triangular rotor engine. This ensured that the movement pattern, in-cylinder temperature, and in-cylinder mass of the equivalent engine were consistent with those of a triangular rotor engine;  
2. For the equivalent combustion process of a triangular rotor engine, this study equated the in-cylinder working process of the rotary engine with two uniform combustions instead of one. The heat release rate distributions of the two combustion processes were based on two different three-parameter Wiebe functions, and a genetic algorithm was used to obtain piecewise equivalents for the two functions. This ensured that the in-cylinder pressure, in-cylinder temperature, and P-V plots of the equivalent engine were consistent with those of the triangular rotor engine;  
3. To verify the correctness and accuracy of the equivalent simulation model established in this study, the in-cylinder volume, pressure, temperature, and mass curves obtained using a three-dimensional simulation model and a one-dimensional equivalent simulation model at rated speeds were compared, and the deviation in the main working process (\(-35^{\circ}\) CA to \(135^{\circ}\) CA) was calculated. The results show that the deviation of the equivalent simulation model established in this study mainly occurs in the intake and exhaust stages (\(135^{\circ}\) CA to \(540^{\circ}\) CA), the deviation in the main working stage (\(-35^{\circ}\) CA to \(135^{\circ}\) CA) is small, the maximum relative error is below \(10\%\), and the average relative error is below \(6\%\); the deviation of the maximum pressure in the cylinder was \(0.4572\%\), and the angle deviation was \(1.4004^{\circ}\) CA; the deviation of the maximum in-cylinder temperature was \(0.1381\%\), and the angle deviation was \(2.0058^{\circ}\) CA. Moreover, the deviations in in-cylinder pressure and temperature at different speeds were minimal, which proves the correctness and accuracy of the equivalent simulation model established in this study. Thus, the equivalent simulation model can meet the needs of the performance simulation of a rotary engine. In subsequent research, we will expand the scope of research, conduct equivalent research on rotary engines with different structures and different fuels, and enhance the universality of the equivalent research method of triangular rotary engines. Methodology, L.L.