, 43:211 | Cite as

State-of-the-art technology in variable compression ratio mechanism for spark ignition engine

  • Ashish J Chaudhari
  • Vinayak Kulkarni
  • Niranjan Sahoo


Present investigations deal with development of a novel variable compression ratio (VCR) mechanism and its implementation in a small and relatively large size single-cylinder engines. Operation of this mechanism is found to be smooth and effective in the running condition of the engine as well. This mechanism, when incorporated in the small size spark ignition HONDA engine, portrayed improvement in engine performance with increment in compression ratio (CR) for petrol and kerosene. Their respective optimum CRs 5.02 (petrol) and 5.27 (kerosene) are higher than the base value 4.8. In case of large size KIRLOSKAR engine, the present VCR mechanism is found to be useful while operating with liquefied petroleum gas (LPG), where measurements showed that combustion duration is lower with LPG for CR 9.79 as compared with base value 9.0. The present experiments clearly demonstrate the usefulness of VCR mechanism in improving engine performance for a given fuel and broadening the range of alternative fuels burnt in the engine. Ease of fabrication, simplicity in installation, accessibility in troubleshooting and smooth run-time alterations are the advantages with the current novel mechanism.


Variable compression ratio spark ignition engine ball screw assembly engine head modification clearance volume 

List of symbols

\( b \)

width of piston ring

\( BP \)

brake power (W)

\( BSFC \)

brake-specific fuel consumption (kg/kW-h)

\( BTE \)

brake thermal Efficiency (%)


compression ratio

\( d_{p} \)

diameter of secondary piston (mm)

\( d_{spark} \)

diameter of spark plug (mm)

\( E \)

modulus of elasticity of material (N/mm2)

\( F \)

force on piston due to combustion of fuel air (N)

\( F_{a} \)

axial load (N)

\( F_{r} \)

radial load (N)

\( l' \)

radius of neutral axis before installation (mm)

\( l_{g} \)

circumferential gap of piston ring (mm)

\( LHV \)

lower heating value of fuel (kJ/kg)

\( L_{h} \)

life of ball screw in millions of revolution

\( m_{f} \)

mass of fuel consumed (kg/h)

\( n \)

number of revolutions per cycle (for 4 strokes, \( n = 2 \))

\( N \)

speed (rpm)


design pressure (N/m2)

\( P_{rad} \)

radial load on ring (N)

\( r \)

radius of rope wire (m)

\( r' \)

radius of neutral axis after installation of ring (mm)

\( R \)

radius of rope drum (m)

\( S \)

spring load (N)

\( t_{r} \)

radial thickness of piston ring (mm)

\( t_{w} \)

thickness of secondary cylinder (mm)

\( V_{c} \)

clearance volume (cm3)

\( V_{d} \)

swept volume (cm3)

\( X \)

radial force factor

\( Y \)

axial force factor

\( W \)

brake load (N)

\( \sigma_{allow} \)

maximum allowable stress (N/mm2)


\( act \)


\( aux \)




Authors would like to thank the Department of Science and Technology, Government of India, for the financial support for facility development to carry out the present research.


  1. 1.
    Matson T 1924 Compensating connecting rod for internal combustion engines. US Patent 1506540Google Scholar
  2. 2.
    Kratzer H J 1942 Variable compression ratio internal combustion engines. US Patent 2399276Google Scholar
  3. 3.
    Mansfield W P 1956 Piston means for varying the clearance volume of an internal combustion engine. US Patent 2742027Google Scholar
  4. 4.
    Clarke J R and Tabaczynski R J 2000 Internal combustion engine with adjustable compression ratio and knock control. US Patent 6135086Google Scholar
  5. 5.
    Styron J P 2000 Variable compression ratio connecting rod for internal combustion engine. US Patent 7028647B2Google Scholar
  6. 6.
    Moteki K, Fujimoto H and Aoyama S 2001 Variable compression ratio mechanism of reciprocating internal combustion engine. US Patent 6505582B2Google Scholar
  7. 7.
    Brevick J 2000 Design and development of a pressure reactive piston (PRP) to achieve variable compression ratio. Department of Energy Contract FC02-99EE50576, Final Technical Report 44-49Google Scholar
  8. 8.
    Caris D F and Nelson E E 1959 A new look at high compression engines. SAE Trans. 67: 112–124Google Scholar
  9. 9.
    Abdel V and Osman 1997 Experimental investigation of varying the compression ratio of SI engine under different ethanol–gasoline fuel blends. Int. J. Energy Res. 21: 31–40CrossRefGoogle Scholar
  10. 10.
    Ozcan V and Jehad A A Y 2008 Performance and emission characteristics of LPG powered four stroke SI engine under variable stroke length and compression ratio. Energy Conserv. Manag. 49: 1193–1201CrossRefGoogle Scholar
  11. 11.
    Yuh M and Tohru G 2008 The effect of higher compression ratio in two-stroke engines. SAE 931512: 355–362Google Scholar
  12. 12.
    Heywood J B 1988 Internal combustion engine fundamentals, International Edition. New York: McGraw HillGoogle Scholar
  13. 13.
    Baghdadi M S 2004 Effect of compression ratio, equivalence ratio and engine speed on the performance and emission characteristics of SI engine using hydrogen as a fuel. Renew. Energy 29: 2245–2260CrossRefGoogle Scholar
  14. 14.
    Aina T, Folayan C O and Pam G Y 2012 Influence of compression ratio on the performance characteristics of SI engine. Adv. Appl. Sci. Res. 3(4): 1915–1922Google Scholar
  15. 15.
    Hanipah M R, Michelson R and Roskilly A P 2014 Recent commercial free-piston engine developments for automotive applications. Appl. Therm. Eng. 75: 493–503CrossRefGoogle Scholar
  16. 16.
    Boretti A 2013 Conversion of a heavy duty truck diesel engine with an innovative power turbine connected to the crankshaft through a continuously variable transmission to operate compression ignition dual fuel diesel–LPG. Fuel Process. Technol. 113: 97–108CrossRefGoogle Scholar
  17. 17.
    Hosey R J and Powell J D 1979 Closed loop, knock adaptive spark timing control based on cylinder pressure. J. Dyn. Syst. Meas. Control 101: 64–69CrossRefGoogle Scholar
  18. 18.
    Martyn R 2002 Benefits and challenges in variable compression ratio (VCR). SAE Technical Paper 03-227Google Scholar
  19. 19.
    Sridhar G, Paul P J and Mukunda H S 2001 Biomass derived producer gas as a reciprocating engine fuel—an experimental analysis. Biomass Bioenergy 21: 52–72CrossRefGoogle Scholar
  20. 20.
    Yang J, Huang Q, Peng Z and Yu Y 2011 Simulation of piston-ring dynamics of a marine diesel engine. In: Proceedings of ICTIS 2011, pp. 2525–2536Google Scholar
  21. 21.
    Budynas R G and Nisbett J K 2011 Shigley's Mechanical Engineering Design. New York: Mc-Graw HillGoogle Scholar
  22. 22.
    Bhandari V B 2010 Design of machine elements, 4th ed. New Delhi: Tata-McGraw Hill Education Pvt. Ltd.Google Scholar
  23. 23.
    Mujumdar V V 2013 Ball screw catalogue. Pune: Institute of Applied ResearchGoogle Scholar
  24. 24.
    Chaudhari A, Kulkarni V and Sahoo N 2014 Simulation models for spark ignition engine: a comparative performance study. Energy Procedia 54: 330–341CrossRefGoogle Scholar
  25. 25.
    Indian Standard 1980 Methods of tests for internal combustion engines—declaration of power, efficiency, fuel consumption and lubricating oil consumption. IS: 10000 (Part IV) Edition 1.1Google Scholar
  26. 26.
    Chaudhari A, Kulkarni V and Sahoo N 2015 Effect of variable compression ratio and intake charge dilution on fuel efficiency and emission for a spark ignition engine. SAE Technical Paper.
  27. 27.
    Debnath B, Saha U and Sahoo N 2014 Theoretical route toward the estimation of second law potential of an emulsified palm biodiesel run diesel engine. ASCE J. Energy Eng.
  28. 28.
    Pulkrabek W 2003 Engineering fundamentals of internal combustion engine, 2nd ed. New Jersey: Prentice-Hall, Chapter 4, p. 148Google Scholar
  29. 29.
    Sayin C, Kilicaslan I, Canakci M and Ozsezen N 2004 An experimental study of the effect of octane number higher than engine requirement on the engine performance and emissions. Appl. Therm. Eng. 25: 1315–1324CrossRefGoogle Scholar
  30. 30.
    Chandra R, Vijay V K, Subbarao P M V and Khura T K 2011 Performance evaluation of a constant speed IC engine on CNG, methane enriched biogas and biogas. Appl. Energy 88: 3969–3977CrossRefGoogle Scholar
  31. 31.
    Erkus B, Surmen A and Karamangil M I 2012 Comparative study of carburetion and injection fuel supply methods in an LPG fuelled SI engine. Fuel 107: 511–517CrossRefGoogle Scholar
  32. 32.
    Huang J and Crookes R J 1998 Spark ignition engine performance with simulated biogas – a comparison with gasoline and natural gas. J. Inst. Energy 71: 197–203Google Scholar
  33. 33.
    Chiang C J and Stefanopoulou A G 2009 Sensitivity analysis of combustion timing of homogeneous charge compression ignition gasoline engines. J. Dyn. Syst. Meas. Control 131: 0145061–5CrossRefGoogle Scholar
  34. 34.
    Holman J P 1996 Experimental methods for engineers. New York: McGraw-HillGoogle Scholar
  35. 35.
    Kline S J and McClintock F A 1953 Describing uncertainties in single-sample experiments. Mech. Eng. 75: 3–12Google Scholar
  36. 36.
    Moffat R J 1982 Contributions to the theory of single-sample uncertainty analysis. J. Fluids Eng. 104: 250–258CrossRefGoogle Scholar

Copyright information

© Indian Academy of Sciences 2018

Authors and Affiliations

  • Ashish J Chaudhari
    • 1
  • Vinayak Kulkarni
    • 1
  • Niranjan Sahoo
    • 1
  1. 1.Centre for EnergyIndian Institute of Technology GuwahatiGuwahatiIndia

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