Main Indicators for Evaluating the Fuel of Diesel Generator Sets

Diesel is the main fuel for diesel generator sets, and an important working medium for diesel generator sets to perform mechanical work. The main requirements for diesel generator sets on diesel are good ignitability, good atomization, good low-temperature fluidity, and low combustion products. Corrosive Xiaohuang mechanical acrobatics and low moisture content are the six items, so do you know what are the main indicators for evaluating the fuel of diesel generator sets? Let's learn about it with Dingbo Power.

1. Cetane number.

Cetane number is an index for evaluating the ignition performance and fuel performance of diesel. Good ignition performance of diesel refers to the low self-ignition temperature of diesel. ) Is shorter, the combustible gas mixture formed during the stagnation period is less, the pressure rise rate after fire is lower, and the work is softer.

The method for determining the cetane number of diesel is similar to the octane number of gasoline. Mix the cetane C16H34, which has the best spontaneous flammability (with a cetane value of 100) and the worst a-methyl tea (with a cetane value of 0), in a certain ratio. When the spontaneous ignitability of the tested diesel is the same as that of the mixture, the volume percentage of cetane contained in the mixture is the cetane number of the tested diesel.

The higher the cetane number of diesel, the better the spontaneous combustion, the diesel engine is easy to start, and the work is soft. But the higher the cetane number, the heavier the diesel fraction, the higher the viscosity, the poorer spray quality, and the short flame retardation period. It catches fire before it can form a good combustible mixture, so the combustion is incomplete and black smoke is emitted. Therefore, the cetane number of diesel should be adapted. The diesel used for high-speed diesel engines is between 40 and 60, and the diesel used for low-speed diesel engines is between 30 and 50.

2. Freezing point and cloud point.

The low temperature fluidity of diesel fuel is determined by the freezing point and cloud point.

At low temperatures, the paraffin and moisture contained in the diesel begin to crystallize, and the diesel becomes turbid. This temperature is called the cloud point. When the temperature drops again, a paraffin crystal network is formed, and the fuel loses fluidity and solidifies. This temperature is called the freezing point. Generally, the cloud point is 5-10°C higher than the freezing point.Domestic light diesel is labeled according to its freezing point. For example, -10 light diesel has a freezing point of -10°C. When the freezing point of diesel is too high, it is easy to block the oil circuit and filter in winter, causing insufficient fuel supply or even interruption. When using diesel oil, the freezing point is required to be 4~6°C lower than the lowest ambient temperature.

3. viscosity.

The atomization performance of diesel fuel is mainly determined by the viscosity. Viscosity is an important physical property parameter of fuel. It affects the spray quality, combustion filterability and fluidity of diesel. The higher the viscosity, the larger the sprayed oil particles, which will worsen the combustion. If the viscosity is too low, it will increase the leakage and wear of the fuel injection pump and the fuel injection nozzle assembly. Therefore, the viscosity of diesel should be adapted. Generally, the kinematic viscosity of light diesel is 2.5-8mm2/s at 20°C.

4. distillation range.

Distillation range indicates the vapority of diesel oil. The lighter the distillate of diesel (the lower the distilled temperature), the faster the evaporation, which is conducive to the formation of mixed gas. The heavy fraction evaporates slowly, and it catches fire before it evaporates in a high-speed diesel engine, and it is easy to emit black smoke. But it is not good if the distillate is too light, because the evaporation is too good, too much mixed gas is formed during the flame retardation period, the pressure rises sharply after the fire, and the work is rough.

The above four items are the main indicators for evaluating diesel performance. At present, light diesel is used for high-speed diesel engines, heavy diesel is used for medium and low-speed diesel engines, and heavy oil is used for large low-speed diesel engines.

If you are interested in diesel generators, or want to know more about diesel generators, please contact us by email dingbo@dieselgeneratortech.com.