බාහිර දහන එන්ජිම ගැන කතා කරමු.
The Underdog - External Combustion engine
If you've been out and about the cars guide website, you would have gained a fair bit of knowledge on cars engines. Enough for you to chat up some of your petrol head associates. But have you heard of External combustion engines? You would have heard of the internal combustion engine in the front end of your car but do you know where an external combustion engine is used.
Two main engine types
When considering fuel combustion engines we can categorize our itinerary into two criterias one being internal combustion engines and the other external combustion engines.
In comparison to internal combustion engines the efficiency of external combustion engines is considerably low.Therefore we see a minimal use case for external combustion engines with fewer possible use cases.
Things you should know about an external combustion engine
The efficiency of a piece of machinery is calibrated with the work done by the said machinery.Engines have a relatively high work rate compared to other power generating systems. In the scenario of external combustion engines the combustion happens outside said chamber or workload enforcer as the name suggests. In theory it creates heat using fuel to change the state of water to steam which creates a relatively higher pressure within a closed system.The steam creates the movement while eventually condensation of the steam results in reformation of water molecules although the efficiency depends solely on the contraption and engineering involved. It's difficult to say that all the water that vaporizes is then condensed even in perfect conditions . However we can assume a fairer percentage is converted for the said reactiion which in itself is a cyclic process.
Why would you use an external combustion engine
The classic example of this use case is the steam engine. The engineering of this engine can be demonstrated in smaller structures as well as in larger structures.Best example of said larger structure is within trains . A steam engine within a train uses coal to to keep going and create steam which in turns creates the higher pressure differential within the vapour chamber which is water converted to rotational motion.
Are there different types of external combustion engines
We can sort out two different types of external combustion engines which can be named as single phase external combustion engines and dual phase external combustion engines.
In single phase external combustion engines the fluid exists in either liquid or steam form for its functionality and does not change states depending on the use case while on the other hand dual phase external combustion engines use a fluid that exists in both states in an ideal scenario switching between the two in the case of heating up and cooling down creating an efficient cyclic process.
What are the key components of an external combustion engine
- Heat source - To keep the engine pressurised there must be an external heat source working around the clock whether it be coal or any other form
- Mechanical system - There must be a mechanical system efficient enough to convert this form energy into mechanical energy using intricate mechanical systems
- Cooling System - A cooling system is required in order to cool down the working fluid whether it is at a higher temperature or in a different state to keep the cyclic process going on. Without it, the external combustion engine would not have any working fluid to work with.
Now you know the intricacies of an external combustion engine so that you can have one up the petrol heads that only consider the internal combustion engine as a viable option.
