About this blog
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.
Spark Ignition Engine
Compression Ignition Engine
SI engines are high speed engines.
CI engines are low speed engines.
SI engines have low thermal efficiency
CI engines have high thermal efficiency.
Petrol is used as fuel, which has high self ignition temperature.
Diesel is used as fuel, it has low self ignition temperature.
Time of knocking
Knocking takes place at the end of combustion.
Knocking takes place at the beginning of combustion.
SI engine works on otto cycle.
CI engine works on diesel cycle.
Homogeneous mixture of fuel, hence high pressure is generated.
Heterogeneous mixture of fuel, hence low pressure is generated.
Constant parameter during cycle
Constant volume cycle.
Constant pressure cycle.