Causes of Cracks in Cylinder Head of Diesel Generator Sets

Cylinder heads are generally made of high-quality gray cast iron or alloy cast iron, while diesel engines mostly use aluminum alloy cylinder heads. Aluminum alloy has good thermal conductivity, which is beneficial to improve the compression ratio of the engine. Secondly, it has excellent casting performance and is suitable for casting parts with complex structures. However, attention must be paid to the cooling of the aluminum alloy cylinder head, and the temperature of the bottom plane should be controlled below 300 degrees Celsius, otherwise, the overheating of the bottom plane will cause plastic deformation and warping.

The function of the cylinder head is to seal the cylinder, form a combustion space together with the piston, and withstand the effect of high temperature and high pressure gas. The cylinder head is subjected to mechanical loads caused by gas forces and tightening of cylinder bolts, as well as high thermal loads due to contact with high temperature gas. In order to ensure a good sealing of the cylinder, the cylinder head can neither be damaged nor deformed. For this purpose, the cylinder head should have sufficient strength and rigidity. The following are the design requirements for the cylinder head:

1. The structure of the cylinder head is complex, and the temperature field is seriously uneven, resulting in large thermal stress, which may cause cracks and overall deformation of the cylinder head in severe cases, sufficient rigidity and strength, small working deformation, and ensure sealing.

2. Reasonably arrange the combustion chamber, valve and air passage to ensure the working performance of the engine, the processability is good, the temperature field is as uniform as possible, the thermal stress is reduced, and the thermal cracking phenomenon is avoided.

The main reasons for cracks in the cylinder head:

1. In the severe cold season, the cooling water in the engine water channel and the radiator is not drained in time after parking, and it freezes and cracks.

2. When the engine is overheated, the sudden addition of cold water will cause the thermal stress on the cylinder head to change suddenly and cause cracks.

3. The influence of residual stress in the casting of the cylinder head and the wall thickness of the cylinder head in production is too thin and the strength is insufficient.

Inspection of Cylinder Head Cracks:

Cylinder head and cylinder block should be checked for cracks with water pressure at the same time. Usually the pressure is required to be 350 ~ 450kPa for 5min. If it is found that there are water droplets oozing out of the cylinder block and cylinder head, it means that there are cracks there.

Jiangsu Starlight Electricity Equipments Co.,Ltd. is a manufacturer of professional generators, diesel generator sets, Cummins generator sets, Volvo generator sets, etc. The company has advanced testing equipment, excellent production technology, professional manufacturing technology, perfect quality management system, and Strong R&D technical strength. It can provide 15KW-2500KW various specifications of universal, automatic, four protection, automatic switching, low noise and mobile, etc., high-quality, low-energy generating sets to meet customer power needs, and can also meet users' different voltages and different frequencies, as well as the power supply system of multiple units connected in parallel, welcome customers to inquire. For more details, please contact us with sales@dieselgeneratortech.com