Motorcycle Engine Cooling System

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Motorcycle Engine Cooling System - Air Cooling VS Liquid Cooling VS Oil Cooling

Last updated on 09-Jun-2022 , By Saleh

Engine cooling system is a vital feature of a motorcycle. Hence many of us already been well known about the motorcycle engine cooling system. But again still there are so many misconceptions remaining on that term. Hence making this term clearer here is our discussion Motorcycle Engine Cooling System - Air Cooling VS Liquid Cooling VS Oil Cooling. Hence let’s try to learn in detail.

You know a motorcycle engine burns the fuel in support of air and produces power to derive the motorcycle on the road. Therefore air & fuel mixture that compressed in the combustion chamber inside the motorcycle engine and then it burns and produces the power. That power drives the engine parts and finally delivered to the wheel and a motorcycle moves.

Whatsoever in this combustion process the engine also generates huge amount of temperature besides producing power. Here actually a standard temperature condition is needed for the efficient combustion therefore operating the motorcycle engine.

But at the running the engine produces huge & access heat over the standard limit and that is wastage. And this access heat is unnecessary which harmful for an engine.

Also Read: Cold Water Impact On Hot Engine

Hence motorcycle engine cooling system works here to control the temperature within the standard limit cutting off the access heat.

Hence commonly there are two basic cooling system is very frequent in motorcycle engine cooling system. The air cooling and liquid cooling is very well known cooling feature for motorcycle engine.

Beside these two types of cooling there one more type of cooling system also available that is oil cooling system. Hence here in our discussion we will discuss the each type of cooling system of motorcycle engine.

Motorcycle Engine Cooling System - Air Cooled Engine

Air cooled engine therefore air cooling is very frequent and popular as motorcycle engine cooling system.

Air cooling system is very simple in construction and very much cost effective. So lower capacity and simple construction motorcycle very widely uses air cooling feature.

In air cooled engine the engine construction is much uncomplicated in terms of cooling feature. Here the hotter area of the engine remains faced on the way of high air flow line.

Moreover the hotter areas like the engine cylinder block and cylinder head constructed with thin metal fins. This metal fins carry the access heat from the engine block and air flow cuts off the heat and makes them cool. Hence in such way air cooled engine temperature controlled by air.

Air Cooled Motorcycle Engine Features

Air cooled engine allows some additional features for a motorcycle. It allows light weight and low cost of motorcycle. Air cooled engine needed no periodic maintenance for its cooling system.

It’s the better solution for cold weather area where no need for anti-freeze treatment and cold start issue solved effort free.

On counter air cooling system in motorcycle have some limitations. Most of the situation air cooled engines are single cylinder, low capacity and low powered engine.

Commonly they comes with low rev, lower compression ratio characteristics. Higher compression ratio or high rev is possible here but cooling fins can increase engine size and weight.

Hence you can see air cooled V-twin engines are so heavy and big in size. Moreover the air cooled engine needed frequent flow of air, so aerodynamic fairing avoided in air cooled engine motorcycles.

Motorcycle Engine Cooling System - Liquid Cooled Engine

Liquid cooled engine sometime known as water cooled engine. Most of the situation water based cooling liquid used for this type of cooling system. So often it called as water cooled engine.

In liquid cooled motorcycle engine the engine block or cylinder head have no metal fin like air cooled engine. It comes with straight and solid construction from outside. But it has water tunnel around the cylinder block and cylinder head.

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That tunnel is connected with a liquid coolant reservoir and cooling radiator. The radiator is attached facing the high airflow line and also have an additional cooling fan to make the liquid forcefully cool inside the radiator.

Motorcycle Liquid Cooling System – How It Works

In the liquid cooled motorcycle engine there is a close loop of liquid coolant (Source). There also attached a mechanical pump which circulates the liquid coolant within the loop. The pump circulates the liquid toward the engine block, then to the cooling radiator and then the reservoir and aging toward the engine. Thus the cycle continues.

Here in this system the liquid coolant absorbs the access heat when flowing through cylinder block or head and releases that heat when passing trough the cooling radiator. Thus it cools the engine and controls the temperature.

Here in case of over heat situation the attached thermostat relays the signal to ECU. Accordingly the coolant pump circulates the cooling liquid faster or if needed the radiator cooling fan start to work to get the hot liquid of the radiator cool faster. So you can see how precisely the liquid cooling system works.

Liquid Cooled Engine – Advantage and Disadvantage

Liquid cooling system is very frequent in higher capacity and high performance motorcycle engines. This type of cooling allows better cooling for multiple cylinder engines. Therefore higher compression ratio, high rev character easily can be achieved as the engine temperature precisely controlled here.

But in counter there are some disadvantages of liquid cooling system. Liquid cooling is quit expensive feature. It makes the engine construction complex. It increases engine size & weight. And it need frequent periodic maintenance of the cooling system. Moreover in low temperature country liquid cooling system need extra care as the liquid coolant freezing point is an issue.

So you can see the weaknesses of liquid cooling system in motorcycle engine. But it sure for the high performance and big size engine liquid cooling is the best solution as motorcycle engine cooling system.

Motorcycle Engine Cooling System - Oil Cooled Engine

In motorcycle engine cooling system oil cooling is another type of cooling system which is not used in typical type of motorcycles. Many motorcycle manufacturer uses oil cooling system for their motorcycle for various reason.

Actually it depends on related area weather condition as oil boiling and freezing point is different and far wider than water. Moreover engine size and design is another issue adopting oil cooling system for motorcycle engine. And most of the high capacity luxurious motorcycle manufacturer uses this type of cooling system for their giant motorcycles.

In oil cooled motorcycle engine the engine oil used as coolant which circulates inside the engine for lubrication. You know in any type of motorcycle the engine oil simultaneously works as lubricant and also as coolant.

Motorcycle Oil Cooling System – How It Works

In the oil cooled engine the oil circulated in wider range inside the engine. It absorbs the access heat and releases the same through cooling radiator. So it also derived through quite same type of cooling radiator and oil pump. Here the engine sump serves as oil reservoir. Hence for the cooling system and channel circulation it needs additional volume of oil.

Typically in oil cooled motorcycle engine the cylinder block and cylinder head assembly remains air cooled and it constructed quite same like air cooled engine. Therefore the cylinder block & head constructed with quite same type of thin metal fins for air cooling feature.

In addition there also a cooling radiator is attached outside the engine like the liquid cooled engine. But here the radiator size and dimension is different. The radiator set here same way facing the high airflow line and it cools the hot oil by the flow of air.

Oil Cooled Engine – Advantage and Disadvantage

Oil cooled motorcycle engine featured for different purpose we already mentioned earlier. This system better suits for 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.

Whereas oil cooling system is adopted in motorcycle engine to deal some extreme situations so it also has some disadvantages. Oil cooled engine construction & design is little more complex. As engine oil splash cools down the hotter parts inside the engine so its oil circulation channels are quite different than other engine.

Due to cooling system it need larger volume of engine oil. Hence here the oil capacity increased and sump size also increased. So accordingly the engine size and weight also increased. Moreover this oil cooling system also need frequent periodic maintenance and it’s also quite more costly.

Air Cooled VS Liquid Cooled VS Oil Cooled – Which is Better

So after our discussion on motorcycle engine cooling system you may ask as which cooling system is better option for a motorcycle engine. Here the answer is not quite easy and not has any straight answer.

Here both the air cooling and water cooling is standard for motorcycle engine where oil cooling has different purpose. But in answer we can say manufacturers choose the best cooling system for their motorcycle engine which suits best with their specification and features. They determine it doing lot of research on the specific model of motorcycle engine through their R&D.

So we need not to bother for the cooling system much as a user. Hence we have to be sure about the craftsmanship of the manufacturer whether they are dedicated or reputed in their motorcycle design and manufacturing or not; that’s it.

So readers here are all about our today’s discussion on Motorcycle Engine Cooling System - Air Cooling VS Liquid Cooling VS Oil Cooling. Hope you have enjoyed the discussion and enhanced your concept. Therefore feel free to add your feedback in comments bellow and stay connected with us. Again thank you all.

FAQ - Frequently Ask Question:

1. What is engine oil used for?

Ans- Motor oil is used for the lubrication of internal combustion engines. The main function of motor oil is to reduce friction and wear on moving parts and to clean the engine from sludge

2. What are the main 5 functions of engine oil?

Ans- The main 5 functions are-

Engine oil inhibits rust & corrosion- Engine oils consist of rust & corrosion inhibitors that provide protection against regular wear & tear
Engine oil helps in reducing friction
Engine oils help in removing impurities
Engine oil acts as a coolant
Engine oil acts as a gap filler

3. What is the main function of engine?

Ans- The engine is the vehicle's main source of power. The engine uses fuel and burns it to produce mechanical power. The heat produced by the combustion is used to create pressure which is then used to drive a mechanical device.

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