What Is an Oil Cooler?
Oil coolers are devices used to cool and maintain the oil used in car engine oil and industrial machinery at the proper temperature.
It is also called a radiator in cars and motorcycles, and in a broader sense, a heat exchanger. The viscosity of oil can change, depending on its temperature. Since viscosity greatly affects oil performance, the oil must be kept at the temperature at which it performs best.
Oil Coolers are responsible for cooling the oil to keep it at the proper temperature.
Uses of Oil Coolers
Oil coolers are used in automobiles and motorcycles. In the case of automobiles, oil coolers are used in radiators to cool the engine oil and in automatic transmissions such as A/Ts and CVTs to cool the ATF and CVTF.
In FF A/Ts and CVTs, built-in coolers that can be directly installed in the transmission itself are often used. Other applications include construction machinery, industrial machinery, and agricultural machinery.
Principle of Oil Coolers
There are two main types of oil coolers:
1. Water-Cooled Oil Coolers
Water-cooled oil coolers are widely used in automobiles. Oil coolers, which cool the engine oil, are usually called radiators. The engine oil is cooled by the power of coolant called coolant.
The way it works is that the engine oil passes through the cooler core, which is covered by a water jacket through which the coolant circulates. Basically, the lower limit of the cooling temperature is the same as that of the cooling water, so the engine oil temperature is stable regardless of the outside temperature.
2. Air-Cooled Oil Coolers
Air-cooled oil coolers release heat by airflow. The heat is transferred to the oil coolers themselves as the hot oil passes through the oil coolers.
Oil coolers for stationary industrial machines are made of metals with high thermal conductivity, such as brass or brass, and have many fins on the surface. By increasing the surface area with fins, the amount of heat that can be dissipated is increased.
Other Information on Oil Coolers
1. Benefits of Oil Coolers
The primary role of oil coolers is to keep the engine oil at the proper temperature. Engine oil is formulated to perform best at temperatures between 80-100℃.
Cooling the engine oil with oil coolers provides a variety of benefits. The most important effect is to maintain lubricity. Automobiles are made up of a combination of various metal parts such as gears, bearings, and sliding bearings called bushings.
Also, in an engine, the piston slides through the piston chamber. To reduce friction between these parts, oil is essential. By keeping the temperature of the oil in the proper range with oil coolers, the sliding resistance between parts is reduced and the machine can continue to operate normally.
Especially in the case of engines, as output increases, heat from exhaust gases, combustion chambers, and cylinder walls causes the engine oil temperature to rise. Therefore, the temperature is regulated using the power of cooling water. Note that water-cooled oil coolers can prevent the engine oil temperature from dropping too low compared to other oil coolers. This is because the coolant never gets lower than room temperature.
2. Performance Requirements for Oil Coolers
While sufficient cooling capacity is required for automotive oil coolers, there are various other requirements. First, they must be compact and lightweight. Since automobiles are required to have a large occupant space, components that fit inside the engine compartment must always be compact. Lightweight is also an important requirement in terms of fuel efficiency.
Another requirement is that the oil flow resistance must not be too large. If the oil flow resistance is too large, the amount of oil circulating will be reduced and the cooling capacity will also decrease. Also, in a low-temperature environment, the oil needs to warm up quickly. To warm up the oil quickly at low temperatures, it can be said that oil flow resistance is an important requirement.