Improve Radiator Inlet
1.Failure and analysis
Engine "reflow" generally refers to that a large amount of gas is generated inside the engine, which causes a large amount of coolant to overflow from radiator. The reason is that the cylinder head gasket of the engine is damaged and the high-pressure gas in the cylinder enters the cooling system,the other reason is that the engine suddenly stops under high temperature or the load is too heavy, causing the engine to overheat and coolant gasified.
According to observation, there is no cylinder gasket damage or water temperature overheating in the engine.Only small coolant overflow, and it doesn’t overflow when radiator cover is opened while engine running. Therefore, it is noticed that not normal "water return", but because the air in the cooling system is not purged during filling water. To solve this problem, the air in the cooling system must be removed first. Discharge the coolant, add it slowly, and pay attention to exhaust the air in the engine intercooler. The test found that most of the generators still have "water leakage" after the water temperature rises to about 70°C.the maintenance personnel noticed that these generators have added a fuel-based coolant heating cold start device. The cold start device takes water from the warm air outlet of the engine, and the pipe is longer, which is likely to be this part pipe air inside is not easy to drain.
2.Improvement
According to the above analysis, considering that the water intake of the cold start device is on the engine body and cannot be changed, and is affected by the installation space, the location and pipes of the cold start device are inconvenient to change. There is no ideal position for installing the overflow tank, so it is suggested to improve the radiator port exhaust capacity .
As shown in picture, raise the radiator water inlet 30mm and extend it down 60 mm ,the lower end is approximately in the middle of the upper water chamber, and at the same time, open a diameter of 10mm near the top of the upper water chamber on the downward extension.The downward extension section can ensure that the water flow in the upper sump is far away from the inlet, so can keep the inside calm.The upward section can make the air-water mixture in the radiator have a separation process during the overflow and rise process, so that the air floats to the top. After opening the one-way valve, the coolant will return to the upper water chamber and will not be taken out. The vent hole can ensure that when the water level is higher than the radiator outlet, it can be discharged from the radiator.
3.Summary
After above improvement, the coolant was added to the specified water level for test, there was no water leakage at the engine overflow. Through this solution, it can be seen that the improved structure of the radiatorcan be used as one of the solutions to prevent the overflow caused by the poor degassing during the water filling process. Of course, if there is enough installation space, can also install an overflow tank,it is also a way to solve this problem.
