276
Views
1
CrossRef citations to date
0
Altmetric
Research Article

A thermodynamic comparison of rhombic-drive and slider–crank mechanisms for a two-stroke SI engine

ORCID Icon & ORCID Icon
Pages 1060-1077 | Received 09 May 2019, Accepted 23 Jun 2019, Published online: 06 Jul 2019
 

ABSTRACT

In this study, mathematical models of a novel mechanism, rhombic-drive, for a two-stroke, spark ignition (SI) engine, and a two-stroke SI engine with a conventional slider–crank mechanism were performed in MATLAB software. Their performances were compared with kinematic and thermodynamic analyses. Mathematical model was conducted according to real cycle approach and some of the operating parameters such as compression ratio, swept volume, heat release time, and lambda were kept identical for both engines. Pressure, volume, temperature, heat release, heat transfer coefficient, work, piston speed, and acceleration changes were examined. Maximum in-cylinder pressure was taken at 222°CA with 4,188 kPa for rhombic-drive engine while 190°CA with 4,003 kPa for slider–crank mechanism engine and maximum temperature was only 39 K higher for rhombic-drive mechanism engine. Theoretical thermal efficiencies of rhombic-drive and slider–crank mechanism were 31.14% and 31.87%, respectively. Effective power of rhombic-drive mechanism engine was 2.12 kW, whereas slider–crank mechanism engine was 2.17 kW. Mechanical efficiency of rhombic-drive engine was obtained 85.89%, while this was only 86.21% for slider–crank mechanism engine.

Nomenclature

BDC=

Bottom dead center

BSFC=

Brake-specific fuel consumption

CA=

Crank angle

CFD=

Computational fluid dynamics

FPEG=

Free-piston engine generator

GDI=

Gasoline direct injection

IMEP=

Indicated mean effective pressure

Lr=

Rhombic link length (m)

OP2S=

Opposed piston two-stroke engine

OP4S=

Opposed piston four-stroke engine

Q=

Transferred heat quantity (W)

Rr=

Gear pin placement radius

SI=

Spark ignition

TDC=

Top dead center

UAV=

Unmanned aerial vehicle

Uˉp=

Mean piston speed (m/s)

Up=

Instantaneous piston speed

Xb=

Percentage of burned fuel mass

Vd=

Displacement volume (m3)

Vs=

Stroke volume (m3)

Vt=

Total cylinder volume (m3)

Δx=

Thickness of the combustion chamber wall

Δθ=

Total combustion duration (°)

h=

Convection heat transfer (W/m2 K)

hg=

Convection heat transfer on the gas side (W/m2 K)

k=

Adiabatic coefficient

m=

Wiebe form factor

s=

Piston displacement (m)

θ=

Crank angle (°)

θ0=

Crank angle at start of combustion (°)

ω=

Angular speed (rad/s)

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Additional information

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Log in via your institution

Log in to Taylor & Francis Online

PDF download + Online access

  • 48 hours access to article PDF & online version
  • Article PDF can be downloaded
  • Article PDF can be printed
USD 61.00 Add to cart

* Local tax will be added as applicable

Related Research

People also read lists articles that other readers of this article have read.

Recommended articles lists articles that we recommend and is powered by our AI driven recommendation engine.

Cited by lists all citing articles based on Crossref citations.
Articles with the Crossref icon will open in a new tab.