Ignition. Internal combustion engines require ignition of the mixture, either by spark ignition (SI) or compression ignition (CI).
What does CI mean in engine?
Compression ignition (CI) engines
In a compression ignition engine only air or air plus residual combustion gases from the exhaust known as exhaust gas recirculation (EGR) is inducted into the chamber during the intake stroke, and compressed during the compression stroke.
Which is better Si or CI engine?
The high temperatures achieved in CI engines cause the fuel to ignite. SI engines are high speed while CI engines are low speed. SI engines have a lower thermal efficiency than CI engines.
Which is not use in CI engine?
Why methanol is not used in CI engine? Explanation: Methanol is not used in CI engines because of its high octane number and low cetane number. Pure methanol and gasoline in various percentages have been extensively tested in engines and vehicles for a number of years.
What type of fuel is used for SI engine?
SI engines are commonly fueled on gasoline, with the fuel characterized based on octane number. The octane number defines the fuel’s ability to reduce autoignition or knock, with the higher the octane number, the higher the resistance to autoignition.
Why spark plug is not used in CI engines?
But in case of diesel engines spark plugs are not needed. … This eliminates the usage of spark plug as the temperature required to ignite the fuel is obtained on compression itself, so always the compression of diesel engines will be in the range 12 -14. This type of process is governed by constant pressure process.
What is the classification of SI and CI?
The most prominent difference between Spark Ignition (SI) and Compression Ignition (CI) engines is the type of fuel used in each. In SI engines petrol or gasoline is used as fuel, hence these engines are also called petrol engines. In CI engines diesel is used as fuel, hence they are also called diesel engines.
Which is the most preferred CI engines fuel?
engines fuel most preferred are aromatics while for C.I. engines fuel most preferred are paraffins.
Is fuel pump used in CI engine?
Early CI engines used air pressure to deliver the fuel into the cylinder, but nowadays liquid fuel, supplied by a reciprocating plunger pump, is delivered through small bore steel pipelines to the injector, which breaks up the fuel to the required degree and deliver it to combustion region in the chamber.
Can alcohol be used for CI engines?
The direct use of ethanol in CI engines is enabled by ignition improvers, a variety of which is discussed in terms of their effectiveness, working mechanism, exhaust emissions, and economy.