Internal Combustion Engine Parts, Components, and Terminology Explained!

in this video we're going to have a look at engine parts engine components and some of the terminology and nomenclature that you're likely to encounter when you are working with engines we're going to take a look at a four-stroke diesel engine but keep in mind that a lot of combustion engines use the same components there are different variations and different designs available and there is a difference between a two-stroke and a four-stroke engine and the parts that are employed with those two types of engines but a lot of the parts a lot of the terms are common irrespective of what type of internal combustion engine you are looking at by the end of the video you'll know all of the main parts that make up an engine you'll be able to visually identify them you'll know what things like top dead center bottom dead center clearance volume and other terms are and what they mean and generally you'll just have an awareness of which parts go where in an engine and how and when to use certain terms what we're looking at now are the internals of a four stroke diesel engine you can see that we've got some lines indicated on the 3d model these indicate different measurements and points of interest that we're going to define in a moment so let's get stuck right in and we can go straight to the middle of the engine where this blue line is indicated here that indicates the cylinder bore the cylinder is the piece here that surrounds the piston this item in the middle of the screen is the piston and the piston moves up and down in the cylinder although the blue arrow indicates the cylinder bore you can also call it the internal diameter of the cylinder or cylinder id you'll see id or internal diameter and bore as well used a lot in the piping industry because you'll often need to describe the internal diameters of pipes when you join them together so that you get nice smooth flow through each of the pipes so it's much the same here we have a cylinder bore or internal diameter we have our piston that sits within the cylinder bore this area is known as the piston crown we've got a space where our piston rings sit piston rings would actually sit here they're not shown but they would sit where my mouse is and again in this section here and again in this section here the piston rings sit in piston grooves which you can see highlighted now and either side of the piston ring grooves are the piston landings we use the piston rings for sealing the space between the piston and the cylinder liner the cylinder liner just refers to the inside surface of the cylinder and when we get combustion in this space here we use the piston rings to seal the space above the piston and that means that when we have our controlled explosion directly above the piston all of that pressure or the majority of it is going to act on the piston to push the piston downwards although we say we seal the space between the piston rings and the cylinder liner using the piston rings what actually does the ceiling is lubrication oil there's a very thin layer of oil between the piston rings and the cylinder liner and we have to have that oil not just to obtain our seal but because if we didn't have it the piston rings would rub against the liner we'd get micro welding micro seizure and the piston rings would begin to break not only that but we would damage the surface of the cylinder liner so that's something that we do not want because the more we damage the piston rings and the cylinder liner the more of that gas or gases of combustion is going to leak past between the piston rings and the cylinder liner and the more this occurs the more power we will lose because we're not transferring it to the piston which ultimately means we're not transferring it out of our engine and to whatever our load may be the middle of the piston here you can see we've got this circular shaped item this is a wrist pin also known as a gudgeon pin or piston pin it actually goes through the piston as you can see from this angle and then it connects to the conrod also known as a connecting rod conrod is just an abbreviation for connecting rod so don't be thrown off by that here is a conrod and it comes down here and connects onto a larger item that will actually rotate and that is our crankshaft the crankshaft has quite a weird shape although there's a straight line a main rotational point or center axis through the crankshaft it's actually got a up and down kind of shape looks quite squiggly if we look over here we can also see it the reason we have that is because the piston travels linearly up and down within the cylinder but the crankshaft rotates as the crankshaft rotates the connecting rod connects to the piston and it rotates at its base with the crankshaft but it moves up and down with the piston linearly as well so the reason we have this strange shape is just to transfer the linear motion from the piston to rotary motion at the crankshaft the rotary motion is then passed to the load which might be used to drive a pump rotate the wheels on an automobile drive a compressor a generator or whatever the center axis of rotation has been highlighted by this blue cross the red arrow down here indicates that the crankshaft rotates and the other red arrow which goes up and down indicates that the piston moves up and down within the cylinder liner although we say that the connecting rod connects to the crankshaft it doesn't actually physically connect the reason it doesn't physically connect is because we actually put bearings between the conrod and the crankshaft these are plain bearings also known as journal bearings and we lubricate the space between the conrod and the crankshaft specifically directly in this area here slightly dark but i'll try and get a better view of it so roughly where my mouse is here that's the area where we would install the bearing it's lubricated on both sides and it is that lubrication oil that we need to maintain at a certain pressure in order that the con rod and the crankshaft do not touch we never want metal surfaces in the engine to touch because if they do then we're going to get micro welding seizure erosion of parts and other problems like that metal rubbing on metal creates friction which generates heat and that's why we use plain bearings to separate these two metal parts the reason you'll sometimes hear them called journal bearings is because the area where the bearing locates on the crankshaft is referred to as the journal if we have a look at some of the blue arrows now down here we have this blue line this blue line indicates bottom dead center or bdc further up we've got another blue line which indicates top dead center tdc the blue arrow between the two lines indicates the stroke or the length of the stroke of the piston so the piston when it travels downwards will go all the way down to this blue line so all the way down to bottom dead center as it travels up its stroke it moves up to the top here to top dead center the distance between the two is the length of the stroke or the stroke length and when we're talking about strokes we can have a two stroke engine which means the piston goes from top dead center to bottom dead center and then back up again to top dead center that is two strokes one down and one up or a four stroke engine which means the piston goes down up down up and the reason we measure that's four strokes is because we refer to it as one combustion cycle a two-stroke engine achieves one combustion cycle in two strokes a four-stroke engine achieves one combustion cycle in four strokes at the top of the cylinder we've got this blue indication here this is indicating the clearance volume the distance between top dead center and the top of our cylinder the top of the cylinder contains parts that we need in order to keep our engine operating like valves a fuel injector maybe a spark plug etc and that forms our cylinder head so you could say that from top dead center to where the cylinder head begins is where we measure our clearance volume what we actually measure is the distance from tdc or top dead center to our cylinder head and then we take our cylinder bore and take the radius or the diameter to work out the area within the cylinder and then we multiply it by the length in other words we would take pi r squared of the cylinder bore where the blue arrow indicates here and then we would multiply that by the length or the distance from top dead center to the cylinder head and that gives us our clearance volume if we were to measure from the cylinder head all the way down to bottom dead center then we would be able to work out our cylinder volume if we go from bottom dead center to top dead center and we measure that distance we can calculate the swept volume of the cylinder we're literally sweeping using the piston from bottom dead center all the way up to top dead center and then calculating the volume in the space between bdc to tdc so that is swept volume and it's based upon the piston's stroke length the reason we're interested in things like swept volume cylinder volume clearance volume cylinder bore etc is because we can use these calculations then to calculate something more useful like compression ratio and power output if we take the total volume of the cylinder and divide it by the clearance volume then we get our compression ratio this is the same as if we said we take the swept volume plus the clearance volume and divide it by the clearance volume the result is the same as an example let's imagine for a moment that we have a swept volume of 9 a clearance volume of 1 then we would have a compression ratio of ten to one petrol gasoline engines they have low compression ratios typically between about seven to one to nine to one diesel engines have much higher compression ratios maybe somewhere around 15 16 17 to 1 or higher and this is the reason or one of the main reasons why diesel engines are more efficient than petrol or gasoline engines once we know things like the compression ratio and other dimensions of the engine stroke length cylinder diameter swept volume etc then we can calculate the power output of one cylinder and multiply it by the number of cylinders the engine has in order to calculate the engine's total power output there are other factors involved but you can hopefully start to realize that knowing some of these values like clearance volume swept volume etc is actually quite useful because we can derive more information from this basic data that we have let's take a look at the cylinder head briefly on this particular engine we've actually got a fuel injector this item here on other types of engines we may have a spark plug for diesel engines they're what we call compression ignition engines diesel is ignited due to the high pressure increase and high temperature increase that occurs as the piston travels towards the cylinder head with gasoline and petrol engines we control the point of ignition a bit more precisely and we use a spark plug to do this surrounding this particular fuel injector are four valves the valves are these circular items and there are two for allowing the air into the combustion space or into the cylinder and two for exhausting or expelling exhaust gases out of the combustion space typically the air inlet valves are larger than the exhaust gas valves because we want to ensure we get fresh air into the combustion space as quickly as possible this air contains the oxygen that we need in order to get combustion the exhaust gases do not contain oxygen or if they do very little of it and thus we want to get rid of them because if we have less oxygen it means we can burn less fuel and if that occurs that means we get less power out of our engine the valves seat in the valve seat area we have a valve stem and see it over here the valve stem comes up and surround the valve stem at the top we have a spring and it's the springs job to return the valve to the closed position once it's been opened by the rocker arms so these black items up here or this particular one here and the rocker arms are actuated by push rods which are initially moved by a camshaft the camshaft is this item that is long and cylindrical in shape it doesn't actually look long and cylindrical in shape as it's shown here because although it rotates along the center axis attached to the camshaft are things like cam lobes such as you go over here for a moment this black item that is a cam lobe and the number of these cam lobes that you see on a camshaft relates to how many valves the engine may have and sometimes also how many fuel injectors as well the valves are mechanically actuated fuel injectors are also sometimes mechanically actuated and it's the cam lobes pushing up onto the tappets which are at the bottom of the push rods which act upon our rocker arms we've actually got two of them and these are called rocker arms because they rock back and forth they have a pivot point where my mouse is here and as the one side of the rocker arms comes up the other side goes down pushes on a valve bridge see we've got a bridge between the two valve stems and as the bridge is pushed down the springs are compressed and the valve stem is pushed down which leads to the valves opening the springs then return the valve to the closed position when our rocker arms move back up again we have another piece on the side here that is our fuel inlet we've got a fuel inlet connection and it connects to our fuel injector can actually see going here comes in from the left connects into our fuel injector you can see it coming down we go through here you can see the tip of the fuel injector and the fuel injector actually normally has a few dots here maybe four or five six dots and that is the fuel injector tip which is at the end of the nozzle and will spray fuel into the combustion space through those holes we know that the camshaft is used to open and close the valves and sometimes to inject fuel what's interesting though is that the camshaft is driven from the crankshaft via gears or a chain or a belt and although it's the camshaft that controls when the valves open and close and when fuel is injected etcetera because it's coupled to the crankshaft ultimately it operates with the crankshaft as the crankshaft rotates the camshaft rotates also the difference is that the camshaft rotates slower the camshaft rotates at half the speed of the crankshaft the reason for that is because the camshaft only has to perform certain functions at certain times for example we only need to open our air inlet valves for one stroke and for the other three strokes our air inlet valve can remain closed with a two-stroke engine we can directly couple the camshaft to the crankshaft and they can rotate at the same speed this is because one full crankshaft rotation on a two-stroke engine equals one combustion cycle the process then needs to repeat so our camshaft also needs to repeat whatever it is doing after one full rotation typically two-stroke engines do not use a camshaft however when you look at large marine two-stroke engines they often do so i think that pretty much sums up the basics concerning engine parts engine terminology and components etc when you start learning about engines it's essential that when people mention the different parts of an engine you really do know what they are in order that you can follow the conversation and don't have to spend your time trying to remember what a piston pin is what a comrade is what a plane bearing is etc if you memorize all of the parts of an engine if you memorize the terms like cylinder bore top dead center bottom dead center then you really will understand exactly how an engine works and it gives you a very firm foundation upon which you can build more engineering knowledge if you want to learn more about engineering then check out our website we've got over 25 hours of engineering video courses and tutorials we cover everything from valves to pipes to engines to electrical transformers to flanges to motors boilers and other exciting engineering topics if you haven't already done so please do subscribe to the youtube channel share the video on social media or even just tell your friends about us so that they too can learn a little bit about engineering thanks very much for your time when we're talking about camshafts and crankshafts and their rotational speed we don't actually talk about speed we talk about degrees of rotation for example with a four-stroke engine the crankshaft may have 360 degrees of rotation and the camshaft only 180 this is because the camshaft rotates at half the speed of the crankshaft this concept of degrees of rotation is very useful because we can use it to better describe when different processes within an engine occur for example when valves open when they close when fuel is injected when the piston reaches bottom dead center or top dead center etc when we draw a diagram to indicate the degrees of rotation and what occurs as we progress through these degrees we call that diagram a timing diagram and you can have both two-stroke timing diagrams and four-stroke timing diagrams

Channel: saVRee

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Keywords: engine parts, engine parts explained, ic engine, mechanical engineering, how it works, internal combustion engine, connecting rod, engine, crankshaft, engine block, parts, piston, camshaft, engine components, piston ring, fuel injector, piston rings, pistons, what are the, car engine parts, car basics, diesel engine, car knowledge, engine basics, automobile engine, parts of ic engine, engineering, combustion engine, 4 stroke, four stroke, 2 stroke, terminology, nomenclature

Id: fw8Jfoif1BM

Length: 19min 58sec (1198 seconds)

Published: Thu Jan 28 2021