..Philip. wrote:
> Steve wrote:
>> All together, class: "What does static compression ratio have to do
>> with the peak pressure achieved during combustion?"
>>
>> NOTHING!
>>
>
> Steve: That you have attempted to bluster bully when you are short on
> knowledge is evident.
>
> "We" know that turbochargers increase air density within the cylinder
> and therefor ... dynamic compression. This readily evident to
> everyone but you that turbo charged engines running significant boost
> pressures will always have different pistons to reduce cranking
> compression.

To append: The lower compression pistons fitted to a turbocharged engine
also help prevent excessive peak dynamic compression levels, Steve. Known
fact that higher cranking compression reduces the amount of boost you can
safely run ... gasoline or diesel.
--

- Philip

 

..Philip. wrote:

>
> To append: The lower compression pistons fitted to a turbocharged engine
> also help prevent excessive peak dynamic compression levels, Steve. Known
> fact that higher cranking compression reduces the amount of boost you can
> safely run ... gasoline or diesel.

Actually, that's not true for a diesel. Spark-ignition engines are
limited in both CR and boost (or lets say the sum effects of boost and
CR, which equates to the combustion chamber pressure at the instant
before ignition) because detonation will occur at some point, no matter
how high the octane of the fuel used. A diesel, on the other hand, has
no such mechanical limit except the mechanical strength of the
connecting rods, bearings, and crankshaft- and these effects are WAY
beyond consideration in most purpose-built engines (although they're a
real issue in some gasoline engine conversions like Powerstroke and
Duramax). In practical terms, NOX production is the real limiting factor
when you have to meet emissions requirements.

And as for the obvious effects of higher combustion pressures on oil
contamination, I really have to wonder how much real-world experience
you have... have you EVER observed an engine operating under high load
and high boost? Gasoline or diesel? In either case, the typical thing
you can see is a shocking amount of vapor blowing out the crankcase
breather (way beyond what can be handled by positive crankcase
ventilation). And that's on a brand-new just-broken-in engine on a
dynomometer, not some 400,000 mile tired-out rig, either.

The REAL reason that there is such a difference between the engines in
your example (SD22, Cummins, and Navistar/Powerstroke) is because one is
an IDI and the other two are DI, which demand less compression for
starting (when the turbo isn't operating anyway).

 

..Philip. wrote:

>
> To append: The lower compression pistons fitted to a turbocharged engine
> also help prevent excessive peak dynamic compression levels, Steve. Known
> fact that higher cranking compression reduces the amount of boost you can
> safely run ... gasoline or diesel.

Actually, that's not true for a diesel. Spark-ignition engines are
limited in both CR and boost (or lets say the sum effects of boost and
CR, which equates to the combustion chamber pressure at the instant
before ignition) because detonation will occur at some point, no matter
how high the octane of the fuel used. A diesel, on the other hand, has
no such mechanical limit except the mechanical strength of the
connecting rods, bearings, and crankshaft- and these effects are WAY
beyond consideration in most purpose-built engines (although they're a
real issue in some gasoline engine conversions like Powerstroke and
Duramax). In practical terms, NOX production is the real limiting factor
when you have to meet emissions requirements.

And as for the obvious effects of higher combustion pressures on oil
contamination, I really have to wonder how much real-world experience
you have... have you EVER observed an engine operating under high load
and high boost? Gasoline or diesel? In either case, the typical thing
you can see is a shocking amount of vapor blowing out the crankcase
breather (way beyond what can be handled by positive crankcase
ventilation). And that's on a brand-new just-broken-in engine on a
dynomometer, not some 400,000 mile tired-out rig, either.

The REAL reason that there is such a difference between the engines in
your example (SD22, Cummins, and Navistar/Powerstroke) is because one is
an IDI and the other two are DI, which demand less compression for
starting (when the turbo isn't operating anyway).

 

Steve wrote:
> .Philip. wrote:
>
>>
>> To append: The lower compression pistons fitted to a turbocharged
>> engine also help prevent excessive peak dynamic compression levels,
>> Steve. Known fact that higher cranking compression reduces the
>> amount of boost you can safely run ... gasoline or diesel.
>
snipped material regarding gasoline since my dialog is regarding diesel.

> A diesel, on the other hand, has no such mechanical limit except the
> mechanical strength of the
> connecting rods, bearings, and crankshaft- and these effects are WAY
> beyond consideration in most purpose-built engines (although they're a
> real issue in some gasoline engine conversions like Powerstroke and
> Duramax). In practical terms, NOX production is the real limiting
> factor when you have to meet emissions requirements.

We should agree here because detonation is combustion starting before
scheduled ignition, which in the diesel arena begins when fuel first exits
the injector.

> And as for the obvious effects of higher combustion pressures on oil
> contamination, I really have to wonder how much real-world experience
> you have... have you EVER observed an engine operating under high load
> and high boost? Gasoline or diesel? In either case, the typical thing
> you can see is a shocking amount of vapor blowing out the crankcase
> breather (way beyond what can be handled by positive crankcase
> ventilation). And that's on a brand-new just-broken-in engine on a
> dynomometer, not some 400,000 mile tired-out rig, either.

Spent 12 years driving line haul, some of that as O/O. Being that road
draft tubes are illegal since about 1990, one does not see blow-by belching
forth under the cab. I recall well the days when you'd see a turbo glowing
dull red on a long pull. Obviously the driver wasn't paying attention to
the pyrometer limit of 1100 degrees. The company I retired from kept OTR
trucks to 600k miles typically. The engines were fine for the most part.
Turbos however were considered expendable items.

> The REAL reason that there is such a difference between the engines in
> your example (SD22, Cummins, and Navistar/Powerstroke) is because one
> is an IDI and the other two are DI, which demand less compression for
> starting (when the turbo isn't operating anyway).

I recall making that distinction some time ago regarding soot production.
ID injection diesel does not have the flame front dampening that IDI
combustion chambers provide. Of course, there are trade-offs but emissions
and 'greeness" rule so .... IDI.

--

- Philip

 

Steve wrote:
> .Philip. wrote:
>
>>
>> To append: The lower compression pistons fitted to a turbocharged
>> engine also help prevent excessive peak dynamic compression levels,
>> Steve. Known fact that higher cranking compression reduces the
>> amount of boost you can safely run ... gasoline or diesel.
>
snipped material regarding gasoline since my dialog is regarding diesel.

> A diesel, on the other hand, has no such mechanical limit except the
> mechanical strength of the
> connecting rods, bearings, and crankshaft- and these effects are WAY
> beyond consideration in most purpose-built engines (although they're a
> real issue in some gasoline engine conversions like Powerstroke and
> Duramax). In practical terms, NOX production is the real limiting
> factor when you have to meet emissions requirements.

We should agree here because detonation is combustion starting before
scheduled ignition, which in the diesel arena begins when fuel first exits
the injector.

> And as for the obvious effects of higher combustion pressures on oil
> contamination, I really have to wonder how much real-world experience
> you have... have you EVER observed an engine operating under high load
> and high boost? Gasoline or diesel? In either case, the typical thing
> you can see is a shocking amount of vapor blowing out the crankcase
> breather (way beyond what can be handled by positive crankcase
> ventilation). And that's on a brand-new just-broken-in engine on a
> dynomometer, not some 400,000 mile tired-out rig, either.

Spent 12 years driving line haul, some of that as O/O. Being that road
draft tubes are illegal since about 1990, one does not see blow-by belching
forth under the cab. I recall well the days when you'd see a turbo glowing
dull red on a long pull. Obviously the driver wasn't paying attention to
the pyrometer limit of 1100 degrees. The company I retired from kept OTR
trucks to 600k miles typically. The engines were fine for the most part.
Turbos however were considered expendable items.

> The REAL reason that there is such a difference between the engines in
> your example (SD22, Cummins, and Navistar/Powerstroke) is because one
> is an IDI and the other two are DI, which demand less compression for
> starting (when the turbo isn't operating anyway).

I recall making that distinction some time ago regarding soot production.
ID injection diesel does not have the flame front dampening that IDI
combustion chambers provide. Of course, there are trade-offs but emissions
and 'greeness" rule so .... IDI.

--

- Philip

 

".Philip." <1chip-state1@earthlink.net> wrote in message
news:LwYzd.14009$Z47.1905@newsread2.news.atl.earth link.net...
> Steve wrote:
>> .Philip. wrote:
>
> I recall making that distinction some time ago regarding soot production.
> ID injection diesel does not have the flame front dampening that IDI
> combustion chambers provide. Of course, there are trade-offs but
> emissions and 'greeness" rule so .... IDI.
>

I don't understand what you are implying here. Are you implying that IDI
engines are greener or the other way around?

Huw

 

".Philip." <1chip-state1@earthlink.net> wrote in message
news:LwYzd.14009$Z47.1905@newsread2.news.atl.earth link.net...
> Steve wrote:
>> .Philip. wrote:
>
> I recall making that distinction some time ago regarding soot production.
> ID injection diesel does not have the flame front dampening that IDI
> combustion chambers provide. Of course, there are trade-offs but
> emissions and 'greeness" rule so .... IDI.
>

I don't understand what you are implying here. Are you implying that IDI
engines are greener or the other way around?

Huw

 

Huw wrote:
> ".Philip." <1chip-state1@earthlink.net> wrote in message
> news:LwYzd.14009$Z47.1905@newsread2.news.atl.earth link.net...
>> Steve wrote:
>>> .Philip. wrote:
>>
>> I recall making that distinction some time ago regarding soot
>> production. ID injection diesel does not have the flame front
>> dampening that IDI combustion chambers provide. Of course, there
>> are trade-offs but emissions and 'greeness" rule so .... IDI.
>>
>
> I don't understand what you are implying here. Are you implying that
> IDI engines are greener or the other way around?
>
> Huw

Ah ... we are separated by a common language. ;-) I could have worded my
thought better.

The slower flame propagation imposed by IDI chamber design also makes for
more soot and requires more timing lead. ID chambers don't have the "nooks
and crannies" (so to speak) so flame propagation is faster which in turn
requires less timing lead to achieve BMEP at the same number of degrees ATDC
as an IDI ... all else being equal. It's really amazing how much of the
diesel "cackle" you can remove by retarding injection timing. But you'll
lose power and gain a smokier exhaust.

--

- Philip

 

Huw wrote:
> ".Philip." <1chip-state1@earthlink.net> wrote in message
> news:LwYzd.14009$Z47.1905@newsread2.news.atl.earth link.net...
>> Steve wrote:
>>> .Philip. wrote:
>>
>> I recall making that distinction some time ago regarding soot
>> production. ID injection diesel does not have the flame front
>> dampening that IDI combustion chambers provide. Of course, there
>> are trade-offs but emissions and 'greeness" rule so .... IDI.
>>
>
> I don't understand what you are implying here. Are you implying that
> IDI engines are greener or the other way around?
>
> Huw

Ah ... we are separated by a common language. ;-) I could have worded my
thought better.

The slower flame propagation imposed by IDI chamber design also makes for
more soot and requires more timing lead. ID chambers don't have the "nooks
and crannies" (so to speak) so flame propagation is faster which in turn
requires less timing lead to achieve BMEP at the same number of degrees ATDC
as an IDI ... all else being equal. It's really amazing how much of the
diesel "cackle" you can remove by retarding injection timing. But you'll
lose power and gain a smokier exhaust.

--

- Philip

 

Huw wrote:


>
> I don't understand what you are implying here. Are you implying that IDI
> engines are greener or the other way around?
>
> Huw
>
>

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.

 

Huw wrote:


>
> I don't understand what you are implying here. Are you implying that IDI
> engines are greener or the other way around?
>
> Huw
>
>

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.

 

Steve wrote:
> Huw wrote:
>
>
>>
>> I don't understand what you are implying here. Are you implying that
>> IDI engines are greener or the other way around?
>>
>> Huw
>>
>>
>
> 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.

Bye, Steve. I didn't intend to test your ability to think outside of the
box. But that's what happened. Hurt much?

--

- Philip

 

Steve wrote:
> Huw wrote:
>
>
>>
>> I don't understand what you are implying here. Are you implying that
>> IDI engines are greener or the other way around?
>>
>> Huw
>>
>>
>
> 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.

Bye, Steve. I didn't intend to test your ability to think outside of the
box. But that's what happened. Hurt much?

--

- Philip

 

..Philip. wrote:
> Steve wrote:
>
>>Huw wrote:
>>
>>
>>
>>>I don't understand what you are implying here. Are you implying that
>>>IDI engines are greener or the other way around?
>>>
>>>Huw
>>>
>>>
>>
>>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.
>
>
> Bye, Steve. I didn't intend to test your ability to think outside of the
> box. But that's what happened. Hurt much?
>

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.

 

..Philip. wrote:
> Steve wrote:
>
>>Huw wrote:
>>
>>
>>
>>>I don't understand what you are implying here. Are you implying that
>>>IDI engines are greener or the other way around?
>>>
>>>Huw
>>>
>>>
>>
>>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.
>
>
> Bye, Steve. I didn't intend to test your ability to think outside of the
> box. But that's what happened. Hurt much?
>

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.