Advantages and Disadvantages of using LPG in S.I Engine

The largest use of LPG (Liquefied petroleum gas) at present is as domestic and industrial fuel. However, there is an increasing trend to use LPG as a motor fuel in an automobile sector. Let us see the major advantages of disadvantages of using Liquified Petroleum Gas (LPG) in spark-ignition (S.I) engine.
LPG as fuel in spark ignition engine


  1. Compared to petrol, running the vehicle engine on LPG results in around a 10% increase in consumption.
  2. Due to higher octane rating, the combustion of LPG is smoother and knocking is eliminated and the engine runs smoothly.
  3. When LPG leaks past the rings into the crankcase, it does not wash oil from cylinder walls and does not generate black carbon. Hence, the lubricating layer is not washed away. Thereby, the engine life is increased by 50%.
  4. Due to the absence of carbon deposits on the electrodes of the spark plugs, the life of the spark plugs is increased.


  1. LPG reduces the volumetric efficiency due to its high heat of vaporization.
  2. Handling has to be done under pressure of about 18 bars.
  3. Its characteristics odor is faint, so leakage cannot be easily detected.
  4. Response to blending is feeble.
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Vinodh Reddy is a Mechanical Engineer and Editor-in-chief of ME Mechanical. He holds a Bachelor of Engineering (Honours) degree in Mechanical Engineering. He also blogs at EduGeneral. He is interested in the farming field.

All Comments

  • Amazing post has informative content. Thanks for sharing the informative post.

    raji96 Jun 25, 2019 11:56 am Reply

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