Development and validation of electro-hydraulic camless free-piston engine

The scavenging system in two stroke engine is very important, therefore an electro-hydraulic camless variable valves actuation is developed and the effect of the exhaust valve character change on HFPE engine performance is investigated. Firstly the HFPE working principle and the control strategy are analyzed, and then a 3D CFD model is built by AVL-FIRE software, the piston displacement is obtained by 0D simulation. The simulation results are verified by the ideal scavenging model. The specific distributions of flow field are by plane cut. Further the scavenging parameters, such as trapping ratio, delivery ratio and scavenging efficiency, are analyzed with different intake pressure. In order to optimize the scavenging performance, the scavenging efficiency is affected by intake port height and the exhaust valve timing. Therefore the laws of higher scavenging efficiency are obtained. Experiment is necessary for validating the electro-hydraulic camless variable valves actuation system design. The specific prototype test bench is introduced for experimental study. In addition, the factors that affect variable valves actuation system are tested. Finally, the engine operation results are obtained and the engine performance is analyzed further.