Abstract: Four design solutions are proposed for the folded-cranktrain of an advanced opposed-piston internal combustion engine. The kinematics and dynamics models of the proposed folded-cranktrains are established using Matlab/Simulink and ADAMS, and the best solution is obtained by analyzing the numerical simulation results. The results show that the piston kinematics characteristics of these four solutions are asymmetrical with respect to TDC, and the intake duration and compression duration are different compared with traditional internal combustion engine, which influences the turbulence intensity, scavenging quality and combustion isovolumetric degree. In view of dynamics, the lateral pressure of piston is much lower than that of traditional two-stroke internal combustion engine, which helps to reduce the abrasion of cylinder wall. Since Solution 4 has better spatial structure layout flexibility and system balance, the piston motion is conducive to the improvement in the charging efficiency of engine and the mixing rate of fuel and air; moreover, it also can shorten the ignition delay period, so Solution 4 is the optimal solution.

Key words: power machinery engineering, opposed-piston two-stroke engine, folded-cranktrain, dynamics