Motorcycle engine cooling system: Air cooled Vs Liquid cooled

Nowadays we all know about the rising popularity of motorcycles across the world. And for better performance manufacturing companies offers better engine along with every spare parts. Because we can say engine is considered as the heart of a vehicle, so it better be good. Reason behind the popularity of motorbikes is mostly because of their engine performance. Different categories and segments of bikes are available currently and for them different kinds of engine are there. Almost all manufactured motorcycles have gasoline internal combustion engines which can be four-stroke or two-stroke engines. A few can be seen with Wankel rotary engines which are currently in production. As we all know a motorcycle engine burns the fuel in support of air and produces power to run the motorcycle. In this combustion process the engine also generates huge amount of temperature besides producing power and it must remain in a standard temperature. Therefore the Motorcycle engines need a cooling system and they can be air cooled, liquid cooled and optionally include oil cooling as well. Depending on where and how the bike will be ridden a motorcycle’s air, liquid or oil cooling may play a large part. There are some especial things about these cooling systems which make the difference and for those reason they are being used in different category bikes.

Depending on the cooling system almost everything differs between these cooling methods. From bellow the lines let us see what the major differences between these cooling systems and how the works.

Types of Engine cooling system
Generally we all know there are two cooling systems which are frequently placed in a motorcycle engines as their cooling method. And they air cooling and liquid cooling system for motorcycle engine as we mentioned earlier. Beside these two types of cooling there one more sort of cooling system also existing and that is oil cooling system which is a part of liquid cooled system. That's why to know better about these methods we are going to talk about the each sort of cooling system of motorcycle engine.





AIR cooled motorcycle engine
Air cooled engine of a motorcycle means that kind of engine which is cooled naturally by the outside air that can come during the riding period or from the atmosphere. Other essential thing about air cooled engines is these engines are highly heat absorber. Because of this reason this engine parts can perform throughout higher temperature range. The same thing goes for the cold situations too. But this type of engines is not important in extreme conditions where the winters are really cold and the summers are extremely hot because on that time air flows also differs much then the ideal situation of weather.
On the other hand for high performance bikes this type of engine contains extra cooling fan on them and basic reason behind this is to increase the surface area of the engine for quicker heat exchange with air. So it can be said Overall performance of this type engine will not be short of at any kind of weather.


Liquid Cooled Motorcycle Engines


Liquid cooled
Talking about the liquid cooled motorcycle engines, there are no fan existing at the upper side of this engine and surrounded by the liquid cooling system which means extra liquid needed to short down the temperature of the engine. This type of engine uses liquid coolant to keep the temperature of the engine at most favorable level. When the coolant got inserted, it flows through the channels and absorbs the heat from the engine and comes to the radiator to lose that heat. Sometimes small size fan is located in the tank just because sometimes air inflow of the radiator is not optimum, on that kind of situation those fans brings in the air forcefully to spread out the excess heat.

Oil cooled motorcycle engines
Oil cooling is another type of cooling system which is not seen usually in every type of motorcycles Oil cooling engines are also seen instead of liquid cooled. In oil cooled engines instead of water or air it uses engine oil as a coolant, and it is generally used to remove surplus heat from an internal combustion engine. The hot engine move the engine heat to the oil which then usually passes through a heat-exchanger, which is a type of radiator but it’s not and also known as oil cooler. Many motorcycle manufacturers use this system for their motorcycle for various reasons. Based on areas, weather condition and the boiling and freezing conditions which are different then the liquid or water manufacturer use this type of cooling system at most of the high capacity luxurious motorcycles or massive size bikes.


Differences between air cooled, liquid cooled

These engine cooling systems are preferable depending on different situations and as for now there are no favorites based on their advantages or disadvantages. Both these engines are good and bad in their own conditions. Air cooled engine works better on lower RPM, for this reason these bikes offers a higher Fuel Economy figure. Liquid cooling bikes have a higher compression ratio and work at higher RPM, therefore they give a lower fuel economy, but their performance is better at the higher cc bikes and nothing to worry about speed.

If someone wants to have higher capacity engine bikes and willing to spend-on the extra maintenance costs then they can go for any one from these two. But in case someone didn’t want to spend that extra maintenance, then choosing the air cooling system will be better. At air cooled engines maintenance will be less and also there would be less worries. Sometimes liquid cooled engines create problem like coolant reservoir damage and coolant leakage etc, so users will not face that kind of extra hassle if they choose air cooled engines.

On the other side oil cooling system suits better at the low temperature areas and also in extreme hot weather condition. As the water and water based liquid coolant freezing point and boiling point is not suitable for low temperature area and no even for deserts, so oil cooling is the only cooling solution for such places.

Without these few important differences between these cooling methods are seen in many ways. Among those few are given bellow.

- Air cooled motorcycles are much noisy than liquid cooled motorbikes.

- Air cooled system are mostly seen on cruisers and commuter category bikes, because most of them naturally run at lower RPM then sports category motorbikes.

- Sports category bike commonly contains liquid cooled engines. And those bikes which run in an extreme weather oil cooling system are placed for their engine.

- Air cooled engines provide simplicity, which can be replaced or fixed if some parts got broken. But liquid cooling is difficult to repair and can also be expensive than air cooled engines if any problem occurs.

- Air cooled bikes are cheaper than liquid cooled or oil cooled.

- Liquid cooling is better for long-term durability because it allows tighter construct tolerances than the air cooled engines.

- Air cooled requires less maintenance on the other side liquid cooled and oil cooled is high at maintenance.

Which one can be better and why?
There is a big question about preference of these engine cooling methods. The answer depends on the bike you choose for using which either comes ready with air cooling or liquid cooling. Generally manufacturing companies offers low cc bikes with air cooled engines and buyer has nothing to do with that if they want to buy that model. But if they want to have a higher cc bikes which runs at high RMP then going with the liquid cooled engine will be a better option to choose for better performance. So depending on the manufacturers research both the air cooling and water cooling is standard for motorcycle engine. Oil cooling has different purpose and it can be very useful in different situation. But in answer we can say manufacturers choose the best cooling system for their motorcycle engine which suits best with their specification and features and where it is going to be used. And to do this they complete lots of research on the specific model of motorcycle engine. As we mentioned earlier at this article, liquid cooling systems are actually used for those engines which contains higher compression ratio. When engines have a higher compression ratio and run at higher RPMs, the air cooling is not sufficient to keep the engine within normal operating temperature. Because of this reason liquid cooling is used. Surely, it costs extra for maintenance, but overall it is long lasting. But it will be total waste of time and money if someone thoughts that liquid cooling means a higher engine life or better performance itself. Good caring, properly and regular servicing with fluid changes will last a bikes engine for long time.

Verdict
Over all comparison of these two engines and their performance basis on different situation leads us to prefer liquid cooling engines for high performance bikes. But it’s not that air cooled engines are useless or can’t give good performance. It can also offer better performance for those bikes which runs at low compression ration and RMP. What you will want depends entirely on your ride, so Air cooled engines can also give superior performance depending on the riding conditions. But it can be said for Sports bike or other high compression engine bikes liquid cooling is better, Scooter or cruiser can probably get away with air-cooling system.