Melting pistons.

[Mike]

only if the fuel is igniting would it heat up, but on the compression stroke the fuel begines to compress with fuel and will try to expand towards the top, once TDC is reached the PSI is so great that the fuel explodes and expels energy that pushes our pistons down the bore creating the power stroke.

All the heat is created on the power and exhaust stroke, the intake and the compression run much cooler.

How much is the compression stroke trying to slow the crankshaft? How much heat is being built by the compression stroke, just the air even before the fuel is injected? And yes, I have a cp monitor as well and know exactly what pre-compressions stoke through exhaust stroke pressures are. Just not as good as Jon at reading the data.

You really should get one from Jon, you discover more than you could ever guess.

Autoignition temperature for diesel is published at 410* f, atmospheric pressure is enough to be compressed and build that kind of heat. You'd also be surprised at just how little pressure is created from ignition compared to the compressed pressures in our chambers.

 

[Mike]

compression stroke is BEFORE TDC, nothing wasted there.....this is where pilot and main injection start, should NOT be any ignition yet....

We at least agree on that one.

What part of the compression stroke is wasted with your answer.

This question is:

During the compression stroke, piston going up before the piston goes down on the power stroke, what part of that cycle { potential power } is wasted?

As Jon posted some waste is inevitable.

The compression stroke is not " free " either is the exhaust stroke " the cycle just after power stroke" for that matter.

 

[RENODMAX]

Can't alot of this waste you're going back and forth about somewhat be solved with a simple AFR gauge?

 

[Mike]

Can't alot of this waste you're going back and forth about somewhat be solved with a simple AFR gauge?

It might but I'm not exactly sure how. Something to think about.

I only go back and forth on the point due to the question I have with all quantity injected pre tdc.

 

[RENODMAX]

So can we figure out how much given an injector size and duration how much fuel is being injected btdc? I know it's a nebulous question but if the volume of fuel was figured couldn't we figure heat and the inevitable waste with an afr?

 

[Accelerator]

Dude, you really need to stop the expert routine and just ask questions.

The fuel burns as it's being sprayed in. Any delay results in knock, and a big delay will cause bursting.

is the bursting or comBUSTION not what drives the piston down?

 

[Accelerator]

How much is the compression stroke trying to slow the crankshaft? How much heat is being built by the compression stroke, just the air even before the fuel is injected? And yes, I have a cp monitor as well and know exactly what pre-compressions stoke through exhaust stroke pressures are. Just not as good as Jon at reading the data.

You really should get one from Jon, you discover more than you could ever guess.

Autoignition temperature for diesel is published at 410* f, atmospheric pressure is enough to be compressed and build that kind of heat. You'd also be surprised at just how little pressure is created from ignition compared to the compressed pressures in our chambers.

i see what your saying mike, but what im saying is that the compression stroke is not nearly as hot as the power or exahust stroke.

the compression stroke will try and "slow the piston speed some but it has to to compress the air and fuel, once TDC is reached it all down hill from there, the piston accels downward. this is the main reason our cranks need harmonic ballencers, to minimize the harmonics created from the twisting of the crank from the compression and power stroke.

 

[Accelerator]

We at least agree on that one.

What part of the compression stroke is wasted with your answer.

This question is:

During the compression stroke, piston going up before the piston goes down on the power stroke, what part of that cycle { potential power } is wasted?

As Jon posted some waste is inevitable.

The compression stroke is not " free " either is the exhaust stroke " the cycle just after power stroke" for that matter.

Mike, note sure what your exactly asking here...

 

[Accelerator]

Can't alot of this waste you're going back and forth about somewhat be solved with a simple AFR gauge?

Banks has used one for tuning latley, i will as well. i think that they (AFRG)can hold important info for all of us

 

[Fingers]

The fuel burns as it's being sprayed in. Any delay results in knock, and a big delay will cause bursting.

That isn't exactly true....

Atomized fuel does not burn. It must vaporize first. The state change cools the fuel and the area around it and displaces any O2 within the plume. So the first stage of the injection event is a fuel fog as the leading edge of the fuel state changes. This takes real time, and propogates the plume towards the walls/piston.

The next phase has the vapors coming up to auto-ignition temp. This happens much faster, but still takes real time. But you still don't have ignition. You get some mixing of the air and the vapors here.

Finally, the vapors are up to temp and burn. The added heat back propogates through the plume and quickens the state change of the fuel fog. It also consumes the O2 at the plume boundry. Still, it takes real time for the fog to change state. BUT it is only burning on the border between the plume and the cylinder air. At this stage it resembles a candle flame with its layers.

Knock happens when you get your whole pulse in prior to the leading edge firering. Basically, the whole chamber is filled with fog that lights all at once. Almost like a gasser.

Burst is when you have managed to cool the chamber below auto-ignition temps. Call it a dead load.


But, what do I know......

 

[Accelerator]

That isn't exactly true....

Atomized fuel does not burn. It must vaporize first. The state change cools the fuel and the area around it and displaces any O2 within the plume. So the first stage of the injection event is a fuel fog as the leading edge of the fuel state changes. This takes real time, and propogates the plume towards the walls/piston.

The next phase has the vapors coming up to auto-ignition temp. This happens much faster, but still takes real time. But you still don't have ignition. You get some mixing of the air and the vapors here.

Finally, the vapors are up to temp and burn. The added heat back propogates through the plume and quickens the state change of the fuel fog. It also consumes the O2 at the plume boundry. Still, it takes real time for the fog to change state. BUT it is only burning on the border between the plume and the cylinder air. At this stage it resembles a candle flame with its layers.

Knock happens when you get your whole pulse in prior to the leading edge firering. Basically, the whole chamber is filled with fog that lights all at once. Almost like a gasser.

Burst is when you have managed to cool the chamber below auto-ignition temps. Call it a dead load.


But, what do I know......

Great detail, thanks!

 

[McRat]

That isn't exactly true....

Atomized fuel does not burn. It must vaporize first. The state change cools the fuel and the area around it and displaces any O2 within the plume. So the first stage of the injection event is a fuel fog as the leading edge of the fuel state changes. This takes real time, and propogates the plume towards the walls/piston.

The next phase has the vapors coming up to auto-ignition temp. This happens much faster, but still takes real time. But you still don't have ignition. You get some mixing of the air and the vapors here.

Finally, the vapors are up to temp and burn. The added heat back propogates through the plume and quickens the state change of the fuel fog. It also consumes the O2 at the plume boundry. Still, it takes real time for the fog to change state. BUT it is only burning on the border between the plume and the cylinder air. At this stage it resembles a candle flame with its layers.

Knock happens when you get your whole pulse in prior to the leading edge firering. Basically, the whole chamber is filled with fog that lights all at once. Almost like a gasser.

Burst is when you have managed to cool the chamber below auto-ignition temps. Call it a dead load.


But, what do I know......

Yeah, I know liquids don't burn. I think I've posted that before.

There is a video on the internet somewhere with a high-speed camera using a glass window to record the ignition event. The fuel ignites well before it hit the cylinder wall in that video. Not sure how many microseconds it takes to ignite.

The fuel burns as it's being injected. When it does not, bad things happen. If it takes a few microseconds to ignite, it still is igniting. Kinda like saying a match doesn't ignite when you strike it. Yeah, there is a delay, but it's not significant.

You can inject fuel ATDC and it will burn, even though the temperature is falling, not rising, just as long as the air is still hot enough. Look at a stock timing table. Going by the "delay theory", a Duramax would not idle.

 

[Accelerator]

Yeah, I know liquids don't burn. I think I've posted that before.

There is a video on the internet somewhere with a high-speed camera using a glass window to record the ignition event. The fuel ignites well before it hit the cylinder wall in that video. Not sure how many microseconds it takes to ignite.

The fuel burns as it's being injected. When it does not, bad things happen. If it takes a few microseconds to ignite, it still is igniting. Kinda like saying a match doesn't ignite when you strike it. Yeah, there is a delay, but it's not significant.

You can inject fuel ATDC and it will burn, even though the temperature is falling, not rising, just as long as the air is still hot enough. Look at a stock timing table. Going by the "delay theory", a Duramax would not idle.

are you sure it's not a gas engine video pat?

 

[Accelerator]

Yep gas engine, enjoy!

http://videos.streetfire.net/video/In-Cylinder-Video-How-a-4_167739.htm

 

[Accelerator]

cylinder head design..http://www.howcast.com/videos/7915-Cylinder-Head-Designs

 

[Accelerator]

http://www.gvsmedia.com/video-2/K9ZkDXadpJk/how-diesel-engines-work-and-combustion-theory

Here kitty kitty :rofl:

 

[McRat]

The one I'm think of is a diesel, but it's been years since I saw it.

Why don't you just tell us what your video links are about? Just in case you accidently cross-linked it with your gay porn site.

Not all the readers here have high-speed internet, so asking someone to watch videos to understand your post might take them hours.

 

[Fingers]

Yeah, I know liquids don't burn. I think I've posted that before.

There is a video on the internet somewhere with a high-speed camera using a glass window to record the ignition event. The fuel ignites well before it hit the cylinder wall in that video. Not sure how many microseconds it takes to ignite.

The fuel burns as it's being injected. When it does not, bad things happen. If it takes a few microseconds to ignite, it still is igniting. Kinda like saying a match doesn't ignite when you strike it. Yeah, there is a delay, but it's not significant.

You can inject fuel ATDC and it will burn, even though the temperature is falling, not rising, just as long as the air is still hot enough. Look at a stock timing table. Going by the "delay theory", a Duramax would not idle.

I don't want to get in a pissing match, but the delays are significant. Here is a plot at/near idle. Cold chamber, but not a stone cold engine.

Point is, the injection delay is real, significant, and must be accounted for when tuning. I can pull a dozen plots to show how it varies with boost, ECT, RPM, rail pressure and timing. Does anyone really care? Probably not.

As always....What do I know?

 

[Fingers]

Here is the link to the Youtube video. It even shows the fuel streams prior to ignition.

 

[Accelerator]

The one I'm think of is a diesel, but it's been years since I saw it.

Why don't you just tell us what your video links are about? Just in case you accidently cross-linked it with your gay porn site.

Not all the readers here have high-speed internet, so asking someone to watch videos to understand your post might take them hours.

:rofl: this one is for you!
http://www.youtube.com/watch?v=FwNwbKGnWEg&feature=related

You guys want to learn, well here you go.:cool2: