Resonant Combustion Start Considering Potential Energy of Free-Piston Engine Generator

Mitsuhide Sato, Takumi Goto, Jianping Zheng and Shoma Irie
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Mitsuhide Sato: Faculty of Engineering, Shinshu University, Nagano-City, Nagano 380-8553, Japan
Takumi Goto: Faculty of Engineering, Shinshu University, Nagano-City, Nagano 380-8553, Japan
Jianping Zheng: Faculty of Engineering, Shinshu University, Nagano-City, Nagano 380-8553, Japan
Shoma Irie: Faculty of Engineering, Shinshu University, Nagano-City, Nagano 380-8553, Japan

Energies, 2020, vol. 13, issue 21, 1-17

Abstract: Free-piston engine generators without a crank mechanism are expected to be used in series hybrid vehicles because of their lower losses. The series hybrid system requires a low starting thrust because the engine frequently starts depending on the battery state. This study clarifies the effectiveness of the constant thrust resonance starting method that utilizes the compression pressure of the engine and the spring thrust. The piston must pass the combustion starting point with a predetermined speed to start combustion. Herein, we present a thrust setting method that uses the energy state diagram to optimize the velocity at the combustion start point. A simulation is performed assuming output when mounted on a vehicle. Consequently, the simulation results show that the maximum thrust can be reduced by more than 90% compared to that without resonance. Moreover, the speed at the combustion start point is in agreement with the value obtained using an energy state diagram. An impulse-like combustion pressure is generated in 180 ms, and combustion can be started using resonance, as shown in an experiment using a small-output engine and linear motor. The effectiveness of the constant thrust resonance starting method was confirmed.

Keywords: free-piston engine; mechanical resonance; potential energy; mechanical energy; linear motor; combustion starting (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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