Cylinder Pulling and Piston Burning of 80kW Cummins Generator

How to prevent cylinder pulling and piston burning of 80kw cummins generator? Today Dingbo Power answers for you.

1. The piston and cylinder should have a reasonable fit clearance

To maintain normal movement of the piston in the cylinder and maintain good air tightness, it is necessary to have a reasonable fit gap between the piston and the cylinder. At present, there are several methods for selecting the fit clearance between the piston and cylinder when assembling a diesel engine:

(1) The calculation method only considers the thermal expansion caused by temperature, but in reality, the state changes of diesel engines during working time are very complex, such as the thermal deformation of pistons and cylinders, which are not taken into account. Therefore, the calculation method is only studied theoretically, and there are still certain problems in practical application, so this method has not been widely promoted and applied.

(2) Tension matching method

The tension matching method is to invert the piston into the cylinder, select a certain size of thin plate from the thickness gauge and insert it between the piston skirt and the cylinder wall in a direction perpendicular to the piston. Then, use a scale to pull the thickness gauge and determine the reasonable range of the fitting gap by measuring its frictional resistance.

The more grouped the piston and cylinder assemblies and the smaller the radial clearance value, the more guaranteed the fit clearance can be. Foreign manufacturers often adopt this method.

(3) Group selection method

The grouping selection method is to group the processed pistons and cylinder holes according to different diameters, and then perform the same group matching.

2. Strictly control the working temperature

Due to the fact that 80kW Cummins generator operate at high temperatures, the geometric dimensions of the pistons are constantly changing under the influence of temperature. The higher the temperature, the more severe the expansion of the piston compared to the cylinder, the smaller the gap during operation, and the worse the formation conditions of the lubricating oil film. The greater the frictional heat generated, the further the expansion will be increased; Such a vicious cycle will cause cylinder pulling, or even lock up and burn the piston, especially for new engines and after major repairs during the short driving range stage, the above phenomenon is more likely to occur. Within a certain temperature range, the reserved fit gap can effectively prevent the occurrence of cylinder pulling and piston burning. Therefore, it is very important to strictly control the working temperature (cooling water temperature) of 80kW Cummins generator during operation.

But if 80kW Cummins generator is frequently operated at low temperatures, it will cause a larger gap during operation and cause cylinder knocking, and a large amount of heat energy will be absorbed by the cooling system, causing incomplete combustion of the mixture, resulting in a decrease in power, reduced economy, and increased cylinder wall wear. At present, many operators are afraid of causing cylinder pulling due to high temperature, so they often make the engine temperature lower than higher. In fact, this is not advisable, and it is advisable to maintain normal operating temperature.

The main factor affecting the working temperature of 80kW Cummins generator is the efficiency of the diesel cooling system. Therefore, in the use and maintenance of diesel engines, it is necessary to ensure that the cooling system has reliable control over the temperature of 80kW Cummins generator.