Properties of diesel engine fuel

There are some desirable properties of the Compression Ignition engine for safety, convenience, and handling.

1.  Viscosity

Viscosity can be defined as the resistance to the flow of liquid due to internal friction among the various layer of liquid. The engine performance is affected by this important property of the fuel. When the fuel viscosity is low then the injection pump wear and power loss take place. If the viscosity is high then also filter blockage and excessive pump resistance take place.

2.  Cloud and Pourpoint

Cloud point is referred to the temperature at which the formation of wax cloud in the fuel. On the other hand pour point also refers to the temperature at which fuel losses its flow characteristics. The value of the pourpoint is always smaller than the cloud point. The value of the cloud point should be smaller so that less difficulty takes place in the winter season.

3.  Cetane number

We use the high cetane number fuel in the compression ignition engine to avoid knocking (occurs due to the delay period) in the engine. Cetane number is the manifestation of the burning characteristics of the diesel fuel. If the value of the cetane number is higher than the ignition characteristics of the fuel is good.

4. Engine deposits

It is the major problem in the engine. Carbon atoms are deposited on all parts of the engine. These deposits grow with high viscosity and low volatility. The sulfur molecules in the diesel fuel increase the corrosion and engine deposits. 

5. Volatility

Volatility influences the burning characteristics of the fuel. The fuel should be significantly volatile under the working range of temperature to produce high-quality blending and burning. The volatility quality of the diesel fuel influences the emission and smoke density of the exhaust. Highly volatile fuel helps in easy and quick starting of the engine.

6.  Flash and Fire point

The fire point is the smallest temperature at which fuel vapor will burn continuously for 5 seconds. Whereas flashpoint is also the lower temperature of the fuel but at this point, fuel gives off its vapor and ignites just for a moment. The flash and fire points indicate that we can handle the fuel below these points without any accident.