Abstract: The heat dissipation of air-cooled diesel generators is achieved by using natural wind to directly cool the diesel generators. Water cooled diesel generators are cooled by the coolant around the water tank and cylinder, while oil cooled diesel generators are cooled by the engine’s own oil. The cooling method used for each type of diesel generator depends on the design factors of the diesel generator, and there are still differences in performance among these three cooling methods. The advantage of air-cooled engines is that they have a simple structure and do not require additional auxiliary accessories. The heat dissipation fins on the cylinder block and cylinder head can meet the basic heat dissipation needs of the engine. However, if operated continuously, the engine may experience heat decay due to the too single heat dissipation method. Water cooled engines, on the other hand, have a more significant cooling effect due to the introduction of new fluids for heat dissipation. Even if the diesel engine runs for a long time, the engine temperature will not be too high, making it an excellent cooling method for heat dissipation.
1、 Air-cooled diesel generator
1. Advantages
Zero fault cooling system (natural cooling) air-cooled diesel generators have low cost and occupy less space.
2. Disadvantages
Slow heat dissipation and limited by the form of diesel generators, such as inline 4-cylinder engines, which rarely use air cooling, the middle 2-cylinder engine cannot effectively dissipate heat, so air cooling is only suitable for 2-cylinder diesel generators.
The air-cooled cylinder will be designed with large heat sinks and air ducts. If a well-designed air-cooled diesel generator is loaded, there is no problem at all. Many of them are branded air-cooled engines and do not have cylinders locked due to high temperatures. The zero fault cooling system of diesel generators has a low cost, and as long as it is properly maintained, there will be no problem of high temperatures. On the contrary, the situation of high temperatures in water-cooled engines is more common. In short, air cooling is completely sufficient for single cylinder low speed power generation, so there is no need to worry about long-distance issues.
2、 Water-cooled diesel generator
1. Advantages
It can effectively control the temperature of high power and high speed diesel generators. When the temperature is low, the throttle valve of the water-cooled engine will close until the oil temperature rises to achieve the best lubrication effect. When the temperature is high, the throttle valve will fully open the water tank to start working. When the temperature is too high, the fan will start cooling to the optimal working temperature of the diesel generator. This is the standard principle of water-cooled operation.
2. Disadvantages
High cost, complex structure, and high failure rate due to the large space occupied by an external water tank.
Water cooled diesel generators are a cooling method with good heat dissipation. The principle of water cooling is to cool the cylinder liner and head by wrapping them with flowing water. The basic components of water cooling are a water pump, a water tank temperature control, and a fan. Water cooling is an essential cooling system for multi cylinder, high-power, and high-speed diesel generators (with water oil dual cooling). Small displacement single cylinder engines generally do not require water cooling and cannot generate as much heat.
3、 Oil cooled diesel generator
1. Advantages
The cooling effect is obvious, and the failure rate is low. A low oil temperature can reduce the high temperature viscosity of the oil.
2. Disadvantages
There are restrictions on the amount of oil required for diesel generators. The oil radiator should not be too large. If the oil is too large, it will flow into the oil radiator, causing insufficient lubrication at the bottom of the diesel generator.
Oil cooling uses its own engine oil to dissipate heat through an oil radiator (oil radiator and water tank are basically the same principle, only one containing oil and the other containing water). Because the circulating power of oil cooling comes from the oil pump of the diesel generator, oil cooling only requires an oil fan heater (oil tank). High end oil cooling is equipped with a fan and throttle valve. The oil cooling system is generally equipped with mid-range arcade machines, pursuing stability and fan heating effect. Single cylinder air-cooled machines are more suitable for changing to oil cooling, and changing from single cylinder air-cooled machines to oil cooling only requires adding an oil fan heat exchanger in the middle of the oil passage.
4、 Comparison of advantages and disadvantages
1. The difference between oil cooling and water cooling
Firstly, the heat sink of the oil cooled radiator is very thick, while the heat sink of the water cooled radiator is very thin. Oil cooled radiators are generally very small in size, while water-cooled radiators have a larger body shape. If your machine has both types of radiators, then the larger one is the water-cooled radiator. Another important distinction is that most water-cooled radiators have electronic fans behind them, while oil-cooled radiators are not commonly used (although some two-stroke diesel engines do not use fans for radiator).
2. Advantages and disadvantages
(1) Oil cooler:
An oil cooler is equipped with a radiator similar to a water cooler radiator, which circulates the oil inside the diesel generator to lower the temperature. Compared to a water cooler, its structure is also much simpler. Due to the direct cooling of the oil that lubricates the components of the diesel generator, the heat dissipation effect is also better, which is better than an air-cooled model, but not as good as a water cooler.
(2) Water cooler:
The structure of the water-cooled machine is complex, and the cylinder body, cylinder head, and even the diesel generator box need to be redesigned (compared to equivalent air-cooled machines), requiring specialized water pumps, water tanks, fans, water pipes, temperature switches, etc. The cost is also the highest, and the volume is also larger. However, it has the best cooling effect and uniform cooling. The advantage of a water-cooled engine is that it dissipates heat quickly, can run at high speeds for a long time, and is not prone to heat exhaustion. However, the disadvantage is that the water-cooled engine has a complex structure, and if the pipeline ages over time, it is prone to coolant leakage. If the coolant leaks in the countryside, it will cause the vehicle to break down, posing a certain hidden danger. However, overall, the advantages outweigh the disadvantages.
(3) Air cooler:
The structure of air-cooled diesel engines is mainly manifested in the degree of exposure of the engine. The engine is not wrapped in any package, and as long as it is started, there will be air circulation. Cold air flows through the heat dissipation fins of the engine accessories, heating the air and taking away some of the heat. This cycle can keep the engine’s heat within a reasonable range.
Summary:
Water cooled engines and air-cooled engines are a description of engine cooling methods, as these two types of models use different forms of heat dissipation, resulting in differences in their actual working principles. However, both types of engines essentially utilize natural wind for heat dissipation, except that water-cooled engines have higher heat dissipation efficiency. Generally speaking, water-cooled engines can quickly dissipate the heat generated by the engine’s work during the entire working process by utilizing additional liquid for heat dissipation. However, air-cooled engines are relatively low-energy due to the lack of additional auxiliary cooling systems, but their structure is simpler. As long as the cleanliness of the cylinder head and cylinder block is maintained, their cooling system will not have any faults. However, water-cooled engines require additional water pumps, radiators, coolant, etc., so both the initial manufacturing cost and the later maintenance and repair cost are higher than air-cooled engines.
Post time: Mar-01-2024