Abstract
For a compression ignition (CI) free piston engine linear generator (FPLG), injection timing is one of the most important parameters that affect its performance, especially for the one-stroke starting operation mode. In this paper, two injection control strategies are proposed using piston position and velocity signals. It was found experimentally that the injection timing’s influence on the compression ratio, the peak in-cylinder gas pressure and the indicated work (IW) is different from that of traditional reciprocating CI engines. The maximum IW of the ignition starting cylinder, say left cylinder (LC) and the right cylinder (RC) are 132.7 J and 138.1 J, respectively. The thermal-dynamic model for simulating the working processes of the FPLG are built and verified by experimental results. The numerical simulation results show that the running instability and imbalance between LC and RC are the obvious characters when adopting the injection strategy of the velocity feedback. These could be solved by setting different triggering velocity thresholds for the two cylinders. The IW output from the FPLG under this strategy is higher than that of adopting the position feedback strategy, and the maximum IW of the RC could reach 162.3 J. Under this strategy, the prototype is able to achieve better starting conditions and could operate continuously for dozens of cycles.
Highlights
Due to its unique structure and working principle, the free piston engine has the advantages of mechanical simplicity, low frictional losses, high efficiency, high suitability for multi-fuel or homogeneous charge compression ignition (HCCI) operation, and low emissions [1,2,3,4,5,6,7,8]
Dramatic developments in the technologies of electrical motors and electronic control have made it possible to address the research difficulties of free piston engines, and most importantly, extended the research concerns to applications of a free piston engine coupled with a linear motor or a hydraulic sub-system [9,10,11,12,13,14,15,16,17,18]
The compression ignition (CI) free piston engine coupled with a linear motor (FPLG) is the very type of free piston engine studied in this paper, and a detailed illustration of structure and the operating principle of this type of free piston engine can be found in [2]
Summary
Due to its unique structure and working principle, the free piston engine has the advantages of mechanical simplicity, low frictional losses, high efficiency, high suitability for multi-fuel or homogeneous charge compression ignition (HCCI) operation, and low emissions [1,2,3,4,5,6,7,8]. This paper mainly considers the study of the injection control strategies in the one-stroke starting process on CI FPLG prototype. The motion characteristics of FPLG differ greatly from CE, and the details regarding the relationship between the injection position and the engine performance have not yet been reported Another notable aspect is that the injection timing signal of CE is the crank angle value, which is not suitable for FPE. The in‐cylinder gas pressure results simulation methods are used to study the injection control strategy of the position feedback, and the assigned after testing the experimental rig parameters. By differentiating the position signals with respect to the time interval and thenanalysing smoothingthe it, results a test offrom the velocity feedback and injection control strategy is performed.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
