What is the difference between SI and CI engines knocking?

What is the difference between SI and CI engines knocking?

In S.I. engines detonation is caused by the auto-ignition of end gas towards the end of combustion whereas knocking in CI engines is due to auto-ignition of the first charge at the start of combustion. Larger size of cylinder promotes detonation in SI engines whereas detonation in CI engines is reduced with the same.

Which engine is more efficient CI or SI?

CI engines have higher Thermodynamic Efficiency With a higher compression ratio in CI engines as compared to SI engines, CI engines have a higher thermodynamic efficiency since more work is done with each expansion stroke.

Which has higher speed SI or CI?

Speed achieved by the engine: Petrol or SI engines are lightweight, and the fuel is homogeneously burned, hence achieving very high speeds. CI engines are heavier and the fuel is burned heterogeneously, hence producing lower speeds.

What is SI & CI engine respectively?

Abstract. Natural gas is a fossil fuel that has been used and investigated extensively for use in spark-ignition (SI) and compression-ignition (CI) engines.

What is meant by SI engine?

A spark-ignition engine (SI engine) is an internal combustion engine, generally a petrol engine, where the combustion process of the air-fuel mixture is ignited by a spark from a spark plug.

Which engine is more powerful?

In very simple terms, higher horsepower translates to a higher top speed and a faster car. Conversely, a higher torque figure translates to more power at a lower RPM. When this is taken into consideration, diesel engines are the more powerful of the two.

Why do we not use the same technology to start both SI and CI engines?

Because due to the type of fuel used in each engine!!! In SI engine, petrol has high self ignition point (247–280 C) i.e petrol requires that high temp. to start combustion. It is not possible that the SI engine can’t provide such high temps.

Why diesel engines are called CI engines?

Diesel engines are sometimes called compression-ignition engines because initiation of combustion relies on air heated by compression rather than on an electric spark. As the piston moves away from this position, fuel injection is continued, and the combustion process then appears as a nearly constant-pressure process.

Why do we not use the same technology to start both Si CI engines?

Is CI a diesel engine?

The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to the mechanical compression; thus, the diesel engine is a so-called compression-ignition engine (CI engine).

What is SI engine and ci engine?

Si engine is internal combustion engine that operates on the principle of spark ignition. It uses petrol and utilizes the Otto cycle . The diesel (Ci) engine is also an internal combustion engine, which uses diesel fuel and operates on diesel cycle.

What is a Si engine?

(February 2019) A spark-ignition engine (SI engine) is an internal combustion engine, generally a petrol engine, where the combustion process of the air-fuel mixture is ignited by a spark from a spark plug.

What is secondary ignition system?

SECONDARY IGNITION. An ignition system is a system for igniting a air-fuel mixture. Ignition systems are well known in the field of internal combustion engines such as those used in petrol (gasoline) engines used to power the majority of motor vehicles.

What is a waste ignition system?

The wasted spark system is an ignition system used in some four-stroke cycle internal combustion engines. In a wasted spark system, the spark plugs fire in pairs, with one plug in a cylinder on its compression stroke and the other plug in a cylinder on its exhaust stroke. The extra spark during the exhaust stroke has no effect and is thus “wasted”.