Composition and operation process of the diesel generator set water-cooling system:

Due to water's high specific heat capacity and excellent heat transfer properties between parts and cooling mediums, modern diesel generator sets predominantly use water cooling. Engines that use water as the cooling medium are known as water-cooled engines. The coolant is simply water. The internal combustion engine's water cooling system uses water as a medium to cool heated components and then transfers the heat to the air. The advantage of this cooling method is that it provides more uniform cooling and the cooling intensity is easily adjustable, allowing the internal combustion engine to operate within an optimal temperature range. Additionally, during winter startups, the engine can be preheated using hot water injection or auxiliary electric heating, making it easier to start. Therefore, it is widely used.

The cooling system of diesel engines is typically a forced liquid cooling system, also known as pressure liquid cooling, meaning that diesel engines are equipped with a dedicated cooling pump to circulate the cooling fluid. Depending on the operating conditions of the diesel engine, either an open-loop cooling system or a closed-loop cooling system can be used.

(1) Open-loop Cooling System. The open-loop cooling system refers to the intake and outlet of the diesel engine being open, with the water source being connected by the user during operation. Depending on the model of the diesel engine and the arrangement of the oil cooler, the composition and form of the open-loop cooling system may vary slightly. The direction of the cooling fluid flow is as shown in the diagram.

During diesel engine operation, the incoming water temperature must not be below 60°C. Therefore, appropriate measures should be taken to regulate the suitable incoming water temperature for the open-loop cooling system. Generally, a mixing tank (pond) can be installed between the water source and the diesel engine to connect the engine's in and out water outlets with the water from the source. By controlling the amount of cold water entering the mixing tank, the incoming water temperature of the diesel engine can be regulated.

Closed-loop diesel engine coolant flow

(2) Closed-loop Cooling System. A closed-loop cooling system refers to the diesel engine's cooling system, which forms a complete and enclosed recirculating circuit. For land-based diesel engines, the closed-loop cooling system involves the high-temperature coolant exiting the diesel engine, which is cooled by passing through a water radiator with the help of a powerful fan. The cooled water then cools the diesel engine. The design of the closed-loop cooling system varies depending on the engine model and the use of an oil cooler.

12-cylinder V-type off-highway diesel engine closed-loop coolant flow

Closed-loop cooling fluid flow for diesel engine (oil cooler is air-cooled)