Matching between mechanics and thermodynamics among 4 individual strokes in a 4-stroke engine by non-circular gear mechanism

Abstract

The relationship between engine mechanics and thermo-dynamics has been investigated by means of numerical simulation. The inherent mismatching between the mechanical behaviors and the thermodynamic process in internal combustion engine is identified, which is believed to be one of the important limiting factors of energy efficiency for conventional engines available in the current market. An approach for engine efficiency improvement through optimal matching between mechanics and thermodynamics (OMBMT) is proposed. An ideal matching model is defined and the conflicts due to the constraints among the mapping strokes in a 4-stroke engine are analyzed. A novel mechanical model is built for approaching optimal matching among all 4 individual strokes in a 4-stroke spark-ignition engine, which is composed of non-circular gears (NCG) and integrated with conventional slider crank engine mechanism. By means of digital mechanical model and numerical simulation, the matching gains among all 4 strokes are defined and calculated for quantifying the NCG engine efficiency improvement by comparing with a baseline engine. The potentials with the OMBMT implemented and the enhancements made by NCG mechanism for engines in terms of overall engine efficiency are reported. Based on the results achieved, it is recommended that the feasibility studies and the experimental validations should be conducted to verify the engine matching concept and effectiveness of the NCG mechanism engine model proposed, and the engine performance and NCG design parameters should be further optimized.

Keywords

engine / engine matching / optimization / optimal matching between mechanics and thermodynamics (OMBMT) / matching gain / engine efficiency improvement / non-circular gears (NCG) / NCG engine

References

[1] SINGH G, HOWDEN K C, GRAVEL R M. Advanced combustion engines 2016 annual progress report: Advanced combustion engine program [R]. U. S. Department of Energy, 2016.

[2] LiuH, MaJ, TongL, et al.. Investigation on the potential of high efficiency for internal combustion engines [J]. Energies, 2018, 11(3): 513

[3] HeywoodJInternal combustion engine fundamentals [M], 1988International editionSingapore, McGraw-Hill

[4] TAYLOR C F. Internal combustion engine in theory and practice [M]. The MIT Press, 1985. DOI: https://doi.org/10.7551/mitpress/3851.001.0001.

[5] ZhangB, SuT, ZhangLInternal combustion engine dynamics [M], 2009, Beijing, National Defense Industry Press(in Chinese)

[6] NigusH. Kinematics and load formulation of engine crank mechanism [J]. Mechanics, Materials Science & Engineering, 2015, 1: 112-123

[7] OpalińskiM, TeodorczykA, KalkeJ. The closed-cycle model numerical analysis of the impact of crank mechanism design on engine efficiency [J]. Combustion Engines, 2017, 168(1): 153-160

[8] ShadlooM S, PoultangariR, AbdollahzadehJ M Y, et al.. A new and efficient mechanism for spark ignition engines [J]. Energy Conversion and Management, 2015, 96418-429

[9] ErkayaS, SuŞ, Uzmayİ. Dynamic analysis of a slider-crank mechanism with eccentric connector and planetary gears [J]. Mechanism and Machine Theory, 2007, 42(4): 393-408

[10] LAZAR J. Apparatus for increasing mechanical efficiency in piston driven machines: US Patent 6, 601, 559 [P]. 2003-08-05.

[11] ISLAS J. Drive linkage for reciprocating engine: US Patent 4, 898,041 [P]. 1990-02-06.

[12] McWHORTER, EDWARD M. Internal combustion engine variable throw crankshaft: US Patent 3,686,972 [P]. 1972-08-29.

[13] ZhaoY, HeC. Optimization of matching between engine mechanics and thermodynamics for engine efficiency improvement [J]. International Journal of Advanced Research and Development, 2020, 5(3): 30-40

[14] FERGUSON C R, KIRKPATRICK A T. Internal combustion engines: Applied thermosciences [M]. Third Edition. John Wiley & Sons, 2016.

[15] PrikhodkoA A, SmelyaginA I. Kinematic analysis of mechanism for converting rotational motion into reciprocating rotational motion [J]. Procedia Engineering, 2015, 129: 87-92