Post by steve66! on Feb 21, 2010 20:21:00 GMT 1
Hi all, i knocked this out to use with my class this week! yes that's right, we're actually going to be building a VW type 1 engine in class!
Thought it deserved an airing prior to me making sure my kids are either petrol heads ;D- or put off mechanics for life....
How an engine works.
Almost all cars use internal combustion engines, these are so called because they burn fuel “combust” inside the engine.
How it works
The two types of internal combustion engines are Diesel and Petrol. Here, a petrol engine is looked at.
A mixture of petrol and air is allowed into the engine through an inlet valve. This mixture is then compressed by a piston. The Piston squashes the mixture until it is around 10 times smaller than when it was first sucked in. Now a spark plug ignites the mixture, the mixture burns and, as it burns, it expands and pushes the piston back down the cylinder. The piston now pushes back up and as it does so, the exhaust valve opens and lets the exhaust, or waste gas out.
Generally cars have 4 cylinders, that is 4 holes with a tight fitting piston that travels inside them, moving up and down. However cars can have 2,3,4,5,6,8,10,12 or even 16 cylinders!
The engine is split into two main parts, the block (or case) which is the bottom part of the engine, and the head, which is the top part.
The head is where the valve are, these allow fuel and air in, and waste gasses out of the cylinder.
The block is where the crankshaft is. The crankshaft is attatched to the pistons by the connecting-rods, or con-rods. This means that as the pistons go up and down the crankshaft is forced to spin round. This is what drives the car.
The valves need to be opened at the correct time, this is achieved by the camshaft. This controls the valves by pushing them open at the correct time. On older cars the camshaft was at the bottom of the engine and pushed on rods called push-rods, these in turn, pushed on rockers which pushed on the valves to open them. The valves are held closed by valve-springs. More modern engines use an overhead-cam which pushes directly onto the valves.
The VW type 1 engine is interesting because of two main design features.
Firstly, it is air-cooled, obviously setting fire to petrol is going to be hot and the engine needs to be cooled, usually this is done by flowing water around the engine. The VW used air instead. A large fan pushes air over the engine and cools it.
Secondly, it is a horizontally opposed engine. Most engines have 4 cylinders in a line, but the VW has 2 cylinders each side of the engine block (called a case on the VW) Some other cars such as Subaru's and Porche's also use this layout.
Thought it deserved an airing prior to me making sure my kids are either petrol heads ;D- or put off mechanics for life....
How an engine works.
Almost all cars use internal combustion engines, these are so called because they burn fuel “combust” inside the engine.
How it works
The two types of internal combustion engines are Diesel and Petrol. Here, a petrol engine is looked at.
A mixture of petrol and air is allowed into the engine through an inlet valve. This mixture is then compressed by a piston. The Piston squashes the mixture until it is around 10 times smaller than when it was first sucked in. Now a spark plug ignites the mixture, the mixture burns and, as it burns, it expands and pushes the piston back down the cylinder. The piston now pushes back up and as it does so, the exhaust valve opens and lets the exhaust, or waste gas out.
Generally cars have 4 cylinders, that is 4 holes with a tight fitting piston that travels inside them, moving up and down. However cars can have 2,3,4,5,6,8,10,12 or even 16 cylinders!
The engine is split into two main parts, the block (or case) which is the bottom part of the engine, and the head, which is the top part.
The head is where the valve are, these allow fuel and air in, and waste gasses out of the cylinder.
The block is where the crankshaft is. The crankshaft is attatched to the pistons by the connecting-rods, or con-rods. This means that as the pistons go up and down the crankshaft is forced to spin round. This is what drives the car.
The valves need to be opened at the correct time, this is achieved by the camshaft. This controls the valves by pushing them open at the correct time. On older cars the camshaft was at the bottom of the engine and pushed on rods called push-rods, these in turn, pushed on rockers which pushed on the valves to open them. The valves are held closed by valve-springs. More modern engines use an overhead-cam which pushes directly onto the valves.
The VW type 1 engine is interesting because of two main design features.
Firstly, it is air-cooled, obviously setting fire to petrol is going to be hot and the engine needs to be cooled, usually this is done by flowing water around the engine. The VW used air instead. A large fan pushes air over the engine and cools it.
Secondly, it is a horizontally opposed engine. Most engines have 4 cylinders in a line, but the VW has 2 cylinders each side of the engine block (called a case on the VW) Some other cars such as Subaru's and Porche's also use this layout.
, theres also two 40l v16 engines at billing waste water plant that run on methane (farts) lol they are used to power giant compressors. Also some large industrial engines have no camshaft 
and the mazda RX7/8 has no pistons, and two strokes they dont have camshaft 
If you want to be really technical tell them about the Chrysler A57 Muitibank engine, which is a W 30 arrangement, and was one of the most technically complicated engines ever built, its was a radial engine built using five, six cylinder L head (SV) engines based closely on Cadillac Windsor engine block, these five units were fixed to one central crankcase and planetary drive gear system, apparently the engine would operate quite happily with up to 12 cylinders knocked out of action.
