2 replies to this topic

[gregh55]

hi all,

could somone help me on somthing

what are the operating principles of fuel and exhaust systems on a four stroke carbed engine?

also need to find the operating principles of fuel and exhaust systems on a turbo charged motor?

any help would be great.

cheers

[Boycie]

Sounds like a college assignment?!

There's quite a lot to cover, but the main differences between a turbo-charged and normally aspirated engine is how air enters the engine.

Remember, SUCK (piston drawing air in, inlet valve open), SQUEEZE (piston compressing air, both valves shut), BANG (firing stroke) and BLOW (exhaust stroke where piston raises with exh. valve open to expel waste).

A normally aspirated (or naturally aspirated) engine draws the air (and fuel if not fuel injected) through the inlet, into the head, past the valves and into the combustion chamber using the vacuum created when the piston goes on its downwards stroke. (suck..)

A turbo-charged engine still functions the same way, but also uses exhaust-driven vanes inside the turbo to push air through the inlet (hence, boost pressure).

[davidv]

Great reply Boycie. The starter motor does the first turns to start the engine to draw in with carbs to suck the fuel into the cylinders. The spark plugs run the engines explodes inside the chambers for the up and down of the pistons. Many older cars have 2 valves per chamber 1 in and 1 out. The cam times there open and close on all the chambers. 2 strokes only have ports for in and out no valves they run on the piston travel to run. Very high Revs but they wear out quicker.