Differences Between SI Engine and CI Engine

Spark Ignition (SI) engine can be compared with Compression Ignition (CI) engine system in 7 aspects. Those 7 aspects are engine speed, cycle efficiency, fuel used, time of knocking, cycle operation, pressure generated and constant parameter during cycle.

S.no
Aspect
Spark Ignition Engine
Compression Ignition Engine
1 Engine speed SI engines are high speed engines. CI engines are low speed engines.
2 Cycle efficiency SI engines have low thermal efficiency CI engines have high thermal efficiency.
3 Fuel used Petrol is used as fuel, which has high self ignition temperature. Diesel is used as fuel, it has low self ignition temperature.
4 Time of knocking Knocking takes place at the end of combustion. Knocking takes place at the beginning of combustion.
5 Cycle operation SI engine works on otto cycle. CI engine works on diesel cycle.
6 Pressure generated Homogeneous mixture of fuel, hence high pressure is generated. Heterogeneous mixture of fuel, hence low pressure is generated.
7 Constant parameter during cycle Constant volume cycle. Constant pressure cycle.
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All Comments

  • very good

    hossain Apr 10, 2016 12:39 am Reply
  • thanks it was awesome

    sayed pazhwak Apr 11, 2016 10:35 am Reply
  • Nice one

    Ekundayp Sheriff Jul 25, 2016 12:17 am Reply
  • I find this Information Useful i really appreciate it

    Chindo Benjamin Jul 28, 2016 1:34 pm Reply
  • goods answer

    grijesh chauhan Aug 29, 2016 5:14 pm Reply
  • really thnx a lot thnx u very much

    kanishk Nov 29, 2016 12:28 am Reply

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