No, BMEP is "Brake Mean Effective Pressure," a far cry from the highest pressure attained during combustion. Go look it up.
Depends on the cam and injection timing in that case. I can certainly diddle the cam and injection timing so that both peak pressure and BMEP are lower on the 24:1 engine... but it will be a pig that barely runs.
But that wasn't the case we're considering- we're considering your claim that an SD22 has higher peak pressure than a Cummins B5.9 or Powerstroke because the static compression ratio is higher.
No... YOU picked the comparison when you selected the SD22, Cummins B5.9, and Powerstroke.
I think he either doesn't have a clue what he's saying, or is deliberately hip-hopping sides of the argument just to be disagreeable. He sure started out that way with me, and hasn't toned the rude attitude down one whit.
First it was quoting a Mobil site claiming higher soot contamination with modern engines, and mocking it because an ancient SD-22 produces more soot out the tailpipe so how can a modern "clean" engine put more soot in the oil. I answered.... Then said he'd "Rather trust Mobil than..." me. Then he compares compressions of the SD-22 to a B5.9 and a T444 Powerstroke, and then demands that the rest of us stick to comparing normal aspiration to normal aspiration.
Whatever he's trying to say, he can say it to someone else. I'm done.
I did. thank you for catching my error in terminology so early.
"All else being equal" Why is this so hard for everyone to grapple with?
Bye, Steve. I didn't intend to test your ability to think outside of the box. But that's what happened. Hurt much?
you cannot _increase_ pressure without an _increase_ in temperature. that's adiabatic heating. heatless pressure is /by definition/ static. i'm really not sure how you can confuse this with an engine's ignition scenario.
philip, i don't usually stick my nose into others' pissing matches, but i gotta tell ya, both huw & steve know their stuff. you just keep flinging poo at the fan for your own entertainment.
normal people show up on these groups because they want to learn something. the price we pay for free knowledge on something you don't know is sharing knowledge on the stuff you /do/ know. right now, i don't see you contributing anything except entropy. you're certainly not contributing knowledge. if steve & huw leave this forum because of some dysfunctional need to pick fights outside of your knowledge depth, the rest of us lose, and i have a problem with that. if you have nothing useful to say, keep it zipped & stop poisoning the well for the rest of us.
No confusion ... on my part. The trick wording were "Rapidly rising pressure."
Normal people don't think outside the box very often. Normal people get put off by questions whose answers don't mirror what they've memorized. I've been visiting this forum for nearly 3 yrs under a couple of names. You have no enforcement power beyond reflecting on your own problem ... whatever that is. There is no requirement for you to be involved in any thread, jim
trick words: "You can have pressure but without heat ... no ignition." that directly contradicts your other statement. google "adiabatic heating".
Only if you didn't follow my thought. When you fill a bottle of oxygen to
2000 psi ... how hot is it during this pressurization? The point I alluded to is the importance of "rapidly rising" pressure. That some diesels absolutely require glow plugs is in part ... because cranking speed does not compress the air quickly enough to heat it sufficient to ignite the fuel as it is injected. But when you get the vehicle rolling down a hill at speed and then pop the clutch, the elevated cranking speed is often sufficient to generate the rapid rises in pressure sufficient to ignite the fuel.So what does this non sequitur have to do with soot or the title of this thread?
wow, that's the pot calling the kettle black.
and that's relevant because...
how does no enforcement power reflect my own problem? i don't follow your logic [but i don't follow your thermodynamics either]. you're entitled to say what you want to whomever philip, but i'm telling you, your pissing match with huw & steve is wretched to behold.
again, you confuse static with dynamic. again, google "adiabatic heating" philip. put us out of your misery.
indirect diesels require glow plugs because the adiabatic heating is substantially lost to the head as it flows through the narrow venturi to the combustion chamber. direct injection engines, where the combustion is in the same area as that in which the air was originally compressed, don't lose as much of this heat, even though compression is less. compression rate != compression ratio. you cannot say there is a difference in compression rate between direct & indirect.
the reason you can [just] start an indirect diesel without electrically heating the glow plugs if you tow/roll the vehicle fast enough is that after a number of compression strokes, the glow plug & the combustion chamber area, although not hot, warm sufficiently for losses to decrease to the point where flash can occur. direct injection diesels for the reasons stated above, start easily in all but the worst conditions, rolling, towed or conventionally cranked.
"If thine eye offend thee, pluck it out" LOL
No confusion in evidence. In evidence is your determination.
I never said there was a 'difference in compression rate' (whatever that means, precisely). But you MUST copy/paste the passage that leads you to believe otherwise.
As I detailed earlier in the context of IDI, cold cranking speed is one of the factors that necessitates a glow plug unless/until you can elevate cranking speed to bring about the warmer chamber conditions you've mentioned previously.
Yer sthow sthmart.
On 12/28/2004 12:54 AM jim beam spake these words of knowledge:
Jim, this is usenet 101; he's a troll. The best way to make them go away is to ignore them. It doesn't always work, but nothing else *ever* works.
RFT!!! Dave Kelsen
A Google search of "Dave Kelsen troll" reveals Dave's penchant for labeling as 'troll' anyone who shows him up. Happens a lot.
Wanting people to go away because they prove you're dead wrong doesn't mean they're trolls, Dave.
On 12/28/2004 9:33 AM Gary L. Burnore spake these words of knowledge:
Agreed. How is that relevant to the discussion?
RFT!!! Dave Kelsen
Im not insulting his competence at all, and I'd expect him to check anything I did as well, its basic common sense on safety/expense critical work. Theres no reason for it to be considered an insult, most safety critical work is double checked in industry too, you must be a very sensitive person to get upset over this sort of thing.
Thats sexism, nothing to do with knowing how good she is at her job, keep with the plot.
Quaint story, still not quite seeing your point though. You are basically trying to make out i'm a do nothing, criticising work checker - which is utter bollocks to be quite honest. All I've said is that I've seen enough crap work done to only trust my own work, which (to date) has been faultless, along with diagnosis, though I did point out that i do accept thoughts from others on diagnosis. So really I dont fit your little story. And almost all of the people I'd consider competent to work on my car wouldnt have anyone else work on their car other than themselves. All very well rounded, pleasant individuals, without a streak of sexism too surprisingly.
In all honesty, if you know you are capable yourself you arent going to feel comfortable trusting someone else with the work. Of course if I dont have the equipment (crank regrind etc) I would have to hand it over to someone, but I'd be finding someone I either know personally or is a friend of a friend to do the work. Anyone can talk the talk, not many can walk the walk.
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