How to Choose a Good Diesel Generator

How to Choose a Good Diesel Generator

As a field power source and emergency power reserve, diesel generator sets are widely used in industrial and agricultural production, national defense, science and technology and daily life. So as a diesel generator distributor or dealer, how can we buy a satisfactory diesel generator? Starlight power technology teaches you how to judge and measure the performance of diesel generators from a professional point of view so as to buy products with high cost performance.

Economic indicators

The economic indicator generally refers to the fuel consumption rate and the lubricating oil consumption rate of the diesel engine.

Fuel consumption rate

Fuel consumption rate, it is the diesel engine per kilowatt-hour consumption of fuel A in g / (kWh). The fuel consumption rate per kilowatt-hour in an indicator power meter is called the indicative fuel consumption rate, and the fuel consumption rate per kilowatt hour in an effective power meter is called the effective fuel consumption rate. The former indicates the indicator of diesel engine economy. The latter indicates the economic efficiency of a certain engine. The fuel consumption rate referred to in the diesel engine product description refers to the effective fuel consumption rate. The fuel consumption rate referred to in the diesel engine product description refers to the effective fuel consumption rate. After measuring torque me and rotational speed n, as well as fuel consumption per hour TGT (kg/h) and effective power Pe, the effective fuel consumption rate ge is obtained by the following formula.

ge=Gt/Pe*10^3[g/(kW.h)]

The range of ge [g / (kW.h)] for diesel engines is as follows:

High speed diesel engine  

ge=212~235

Low-speed diesel

ge＝169~190

lubricating oil consumption

The consumption of oil consumption per kilowatt-hour in a diesel engine is called the skid consumption rate in g / (kW h).

The g number of oil consumption per kilowatt-hour in a diesel engine is called the skid consumption rate in g / (kW h). Diesel engine lubricating oil is used continuously in the engine, the main reasons for its consumption are: when the diesel engine is in operation, the lubricating oil enters the combustion chamber through the piston or is burned by the air valve pipe flow in the gas cylinder, and the unburned oil is discharged with the exhaust gas. In addition, a portion of the lubricating oil due to atomization or evaporation in the crankcase by the crankcase vent. Diesel engine oil consumption rate is generally 0. 0. 5-4g/ (kW.h).

Dynamic performance index

The power performance index refers to the external work capacity of diesel engine, generally refers to the power, the average effective pressure, the rotational speed and the piston average speed and so on.

active power

The unit of power of a diesel engine in a unit of time is 1 kW 1 000 N ·m / s.

The work done by a diesel engine per unit time in the cylinder is called indicated power. The power extracted from the engine crankshaft is called effective power after the indicated power is subtracted from the friction loss of the internal parts, the mechanical loss of power such as the pump air torsion loss and the driving accessory loss is subtracted from the engine crankshaft.

If the crankshaft speed per minute is n and the crankshaft output effective power per second is We. the effective power of diesel generator is Pe=PI*nMe/30000(kW）

Me is effective torque

Speed and average Piston Velocity

Speed diesel engine crankshaft per minute speed, expressed by r/min. The speed has great influence on the performance and structure of diesel engine, and its range is very wide. Various types of diesel engine speed range is different.

The average speed of the piston cm is constantly changing in the cylinder, which is larger in the middle of the stroke, smaller in the vicinity of the stop point, and zero at the stop point. If the engine speed n is known, the piston average speed can be calculated by the lower formula.

Cm=2*Sn/60=Sn/30(m/s)

Mean Effective Pressure

The average effective pressure of eight is usually used to compare and evaluate the dynamic performance of various engines. It is a hypothetical pressure acting on the top of the piston, and it is the work done by the piston to move a stroke, equal to the effective work done per cycle.

Pe=i*Vs*Pe*n/30t(kW)

i—number of cylinders ；

Vs-stroke capacity，L；

Pe—mean effective pressure ，MPa；

n —engine speed，r/min ；

t 一Stroke number of engine

So, Pe=30*t*Pe/i*Vs*n

It can be seen that Pe represents the effective power per unit cylinder working volume .Pe is an important index, which not only indicates the working cycle is good or bad, but also includes the size of mechanical loss, the higher the value of Pe is under the same conditions, The more effective work the engine outputs.

The values of Pe are generally as follows:

Non-turbocharged diesel engine is (0. 5—O.9)MPa

Turbocharged diesel engine is (0. 8—3.2)MPa

Exhaust pollution index

There is a small but very harmful amount of emissions in the exhaust of a diesel engine.