The engine cooling system is one of the important parts that is usually installed in the IC engine. It is used to reduce the temperature of the engine’s rotating components. It also helps to reduce the wear out of the component and ensure smooth functioning and long life of the components. According to the cooling process: the engine is divided into the air-cooled engine and water-cooled engine categories. This article mainly explains the air-cooled engine working, parts, and applications.
What is Air Cooled Engine?
An air-cooled engine is a type of IC engine that uses air to remove engine heat and maintain its normal operating temperature, rather than liquid coolant.
In an air-cooled engine, the engine’s temperature is regulated by the flow of air over specific areas of the engine, which dissipate heat and prevent the engine from overheating during operation. This is achieved without the use of liquid coolant, relying solely on the circulation of air to maintain the engine’s operating temperature.
A significant amount of the heat produced by combustion engines, approximately 44%, is released through the exhaust rather than being expelled through the metal fins of an air-cooled engine, which accounts for only 12% of the heat loss. Additionally, roughly 8 percent of the heat energy is delivered to the engine oil, which serves as a lubricant and assists in dissipating heat through a cooler.
These types of engines are more prone to overheating, especially in a humid or hot environment, and may need more frequent maintenance to keep the engine running at its best.
Air-cooled engines are typically used in small engines, motorcycles, general aviation aircraft, lawnmowers, generators, outboard motors, pump sets, saw benches, and auxiliary power units.
Working of Air-Cooled Engine
The air-cooled engine uses the air cooling system. The fundamental principle of an air-cooled engine is to facilitate the flow of air through the parts that generate heat, which is determined by the surface area of the metal in contact, the rate of airflow, and the temperature difference between the hot surface and air.
Unlike liquid-filled radiators, air-cooled engines depend on cooling fins installed in the cylinder head to expel heat. This makes them ideal for applications with limited space.
The cooling fins permit the heat produced by the engine to be dispersed by the surrounding air, akin to how someone would cool down a hot piece of food by blowing on it.
Construction of Air-Cooled Engine
Air-cooled engines utilize extended fins to dissipate heat, which are cooled by passing cool air over them using either a fan in cars or the vehicle’s motion in aircraft and motorcycles.
Some engines may also have ducts or baffling systems to improve airflow, while horizontally opposed cylinders are used to allow unrestricted air flow over the fins.
Oil coolers may also be employed to maintain low oil temperatures. In high-speed air-cooled engines, a gas and oil mixture is used instead of just gas, which helps with cooling.
Conversely, 4-stroke engines retain engine heat due to the presence of oil in the crankcase, necessitating the use of external engine oil coolers to maintain optimal temperatures.
Advantages of Air-cooled Engines
- The air-cooled engine doesn’t have coolant leakage issues.
- These engines warm up very quickly compared to liquid-cooled engines.
- They don’t have coolant freezing issues.
- They have low weight than liquid-cooled engines.
- The air-cooled engine has a simple design.
- They perform better in a hot environment.
- They are less expensive to install.
- They have better fuel efficiency than liquid-cooled engines.
Disadvantages of Air-cooled Engines
- They are more prone to overheat.
- An air-cooled engine contains large fans. These fins may consume a lot of power.
- They are more expensive to build.
- It produced more noise than the liquid-cooled engine.
- It may emit higher levels of pollutants because of its limited cooling capacity and higher combustion temperatures.
- They may experience poor performance issues in cold weather.
- They require high maintenance.
- They usually have lower power output compared to liquid-cooled engines of the same size.
Applications of Air-cooled Engine
- Recreational Vehicles: Air-cooled engines are used in various recreational vehicles, including campers and RVs.
- Aircraft: Air-cooled engines are most commonly used to power small aircraft, including light sport aircraft, helicopters, and ultralights, due to their reliability, simplicity, and light weight.
- Lawnmowers and Outdoor Power Equipment: These engines use to power different chainsaws, lawnmowers, and other outdoor power equipment.
- Motorcycles: They are used to run different motorcycles, particularly those designed for off-road use.
- Agricultural Equipment: They power various agricultural equipment, such as cultivators and tractors.
- Portable Generators: Air-cooled engines are used in various portable generators due to their lower weight, simplicity, and compact size.
Oil Cooled Engine Vs Air Cooled Engine
The main difference between the air-cooled engine and the oil-cooled engine is given below:
| Oil Cooled Engine | Air Cooled Engine |
|---|---|
| The oil-cooled engine uses oil as a cooling agent. | The air-cooled engine uses air as a cooling agent. |
| These are most efficient engines than air-cooled engines. | These are less efficient. |
| They have high reliability. | They are less reliable than oil-cooled engines. |
| It has a low cost. | It has more cost than oil-cooled engines. |
| They are quieter and have less vibration compared to air-cooled engines. | They are louder and have more vibration compared to oil-cooled engines. |
| These have a complex design. | These have a simple design. |
| It has a radiator. | It doesn’t use a radiator. |
| These engines are heavier than air-cooled engines. | These are lighter than oil-cooled engines. |
| They are more expensive. | They are less expensive. |
| They need regular maintenance. | They require very low maintenance. |
FAQ Section
Why do air-cooled engines have fins?
The air-cooled engines contain fins that extend out from the engine. The main function of these fins is to discharge the hot air of the engine into the environment. Then a fan blows fresh cooled air through the fins into the engine. In this way, the fins play a big role in maintaining the engine temperature.
Are air-cooled engines reliable?
Air-cooled engines work efficiently in RVs, motorcycles, and small airplanes. But when you use it for a car, generally it generates many problems, and it does more harm than good.
What are the advantages of Air-Cooled Engines?
The air-cooling engine doesn’t need antifreeze. It has a simple design and requires a low installation area. These types of engines are best for motorcycles, scooters, and some airplanes. They have low weight than liquid-cooled engines.
What are the examples of Air-Cooled Engine?
The air-cooling system is used on the engine, such as combat tanks, airplanes, motorcycles, and scooters.