Combustion
MK sez:
"A friend and I were inquiring w/extrude hone and they seem to think they can poke more holes and change the size of existing ones. "
I'm by no mean a hone expert, but I can't see how they would be able to obtain more holes with it.
There is no real damage to the engine with smoke( other then soot in the oil). Also a little smoke is inherent with the diesel combustion. The real damage you do with BIG SMOKE is to the combustion. Inefficient injection, or too much fuel for the air charge in the cylinder, both harm the combustion. What you see then is smoke. In the case most of us are interested in, it harms HP.
We're way off topic here but I think it's worth to understand this concept better.
Let's say we have an diesel engine on a engine dyno. The engine dyno can apply a variable load to the engine without letting the engine increase it's RPM's. To keep things simple, let's also say the engine has no turbo. Always to keep it simple this engine has a governed low idle speed of 1500 Rpm.
( Imagine the engine dyno like a "brake" applied to the engines crankshaft. As the force applied to the brake increases the load on the engine increases)
Ok, the engine idles at 1500 Rpm, we see absolutely no smoke from it's exhaust. We start to add a little more fuel to each injection stroke. Now the engine should rev higher but at the same time we also increased the load on the engine to maintain the same engine speed. What have we done? We have increased the power the engine produces.
As we go on to increase fuel-load, more fuel-load, more fuel-load
... . , at a certain point we'll start to see smoke from the exhaust.
We have reached the limit of the engines efficient combustion.
(This limit is obviously different for each engine. )
From this limit-point on, as we further increase fuel (load) we'll obtain always more smoke.
What happens? The engine isn't capable to burn all the fuel we're injecting. The smoke we see is oxidized but unburned fuel.
Inside the combustion chamber the excess fuel cools the burning flame thus it "absorbs" part of the combustion energy, which we wanted to translate into Hp.
In our imaginary engine test, we've gained 1 hp for every fuel-load increase. From the "inefficient combustion point" on for every fuel increase we'll see 1/3 Hp increase. As we go further with the fuelling we'll see the HP decrease.
(At a certain point, if we increase the fuel further (much) the engine won't be able to ignite the fuel at all... . )
Now, we let go the brake we've applied to the engine. The engine will rev up until the balance between internal frictional forces and the energy we supply through the fuel is met. At this point we most likely will not have any smoke from the exhaust because with the higher Rpm the engine can breath more air.
For those with a deeper insight into the combustion/engine technology ( I'm sure there are several of you here) I beg your pardon.
I know I've kept things too simple, but I want to make it understandable to the less technically inclined...
Marco
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Marco
