Intake and Exhaust System

Intake and Exhaust System

 

In the boundary of “internal combustion engine” there are something different from those of engines of our cars. An internal combustion engine means a device which burns the fuel for power generation inside of engine, therefore there can be several other forms of internal combustion engines. One of the example is gas turbine which is used for power plant as a bigger form and in aero plane in a small form. This type of engine runs very smoothly with continuous supply of fuel and power generation, therefore we call this type of engine as “flow type internal combustion engine”. On the other hand the engine with cylinder and piston, we call it “volume type internal combustion engine”.

 

Most of the engines used for our vehicles are volume type internal combustion engines, therefore we need a devices which control the air motion into and out of the engines for an optimal operation of combustion function.

 

Air Cleaner

An engine is composed with many fast moving steel components which contact each other, for example, between piston ring and cylinder wall, therefore the air and fuel sucked into an engine need to be very dust-free not to damage the engine components. On the other hand the quality of air is quite not satisfactory or qualified for the an engine supply as it is, therefore we need a cleaner which filter out all the particles which is hard enough to damage steel made engine.

 

I have experienced one case when I was in a diesel engine company. One day I have got a phone call from a truck dealer (imported truck) and he told me “A truck grounded, engine stuck… can you come over here and see what happens ?”  I went down there and investigated what has been happened. The sequence of trouble shooting is always from the simplest one, that was my motto at that time and now also. I  have opened the air cleaner to see how dirty it is. But surprisingly there is nothing inside, only empty can. The dealer had forgotten to install cleaner element after down loading the truck from the ship… And the truck was over.

 

 

 

The traditional air cleaner looks like the round pan located at the middle of engine room but now most of passenger cars have the similar structure like the picture above. And the small square shape plastic box is air cleaner.

 

Valve Devices

A combustion chamber of an engine is a space for “Combustion” to generate the power to propel a vehicle or other devices, therefore, the chamber need to be very tight not to lose any mechanical power. For this purpose we need to have a valve devices which controls the airflow coming into and out of engines before and after combustion based on the rhythm of engine strokes.

 

An optimal shape of valve is like the shutter of cameras which moves very fast and guarantees complete open and close of air channel. In theory maybe this kind of optimal valve devices are possible but in reality that kind of devices are not possible to make. The best functional form which is used looks the pictures below.

 

 

 

Muffler

If the engine operates with raw noise of combustion, probably the street is like battle field. The noise of engine combustion is not small at all. Listen to the engine of car racing specially Formula-1, the engine noise is not small at all. Then what make the engine raw noise down ? Muffler is the one.

 

The sound (noise if it is not wanted) is a air wave with pressure, the bigger sound or noise has bigger pressure. Therefore, to reduce the noise level we need to reduce pressure of the exhaust gas. Inside of the normal muffler the structure show like picture below, guiding the high speed exhaust gas flow in a complicated shape structure to reduce the speed and pressure.

 

 

 

 

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