87 octane '06 Sonata
01-29-2006, 01:56 PM
#76
Guest
Posts: n/a
Re: 87 octane '06 Sonata
gerry wrote:
> [original post is likely clipped to save bandwidth]
> On Sat, 28 Jan 2006 02:17:03 GMT, Matt Whiting <whiting@epix.net> wrote:
>
>
>>gerry wrote:
>>
>>
>>>Look up " detonate" in a good dictionary and you will find it is not as
>>>defined as used in the above reference! It is not "spontaneous
>>>combustion"!
>>>
>>>An example is
>>>
>>>http://www.yourdictionary.com/ahd/d/d0172500.html
>>>
>>>"To explode or cause to explode."
>>>
>>>http://en.wikipedia.org/wiki/Detonate
>>>
>>>states
>>>
>>>"involves a shock wave and a reaction zone behind it"
>>
>>Detonation used in the automotive sense isn't all that different. The
>>spontaneous combustion is in effect an explosion. That is what makes
>>all of the noise. It is the shock wave hitting the cylinder walls,
>>piston and head that makes the racket.
>>
>>
>>
>>
>>>Indeed one detonates a thermo nuclear weapon and that sure is not
>>>spontaneous combustion as defined in the reference you choose
>>>
>>>This is just to point out that different groups use different jargon. Thus
>>>I indicated not to worry too much about folks using different wording. I
>>>concede I use the words in more general engineering context, not
>>>automotive jargon.
>>
>>It makes sense to use automotive jargon when talking about an internal
>>combustion engine, which was the topic at hand.
>>
>>
>>
>>
>>>In context of this discussion and using your choice of wording, octane
>>>affects both "pre-ignition" and "detonation", inhibiting both.
>>
>>Octane inhibits detonation, but has almost no affect on pre-ignition.
>>Pre-ignition typically occurs from hot spots in the combustion chamber.
>> Octane slows down the burn rate and lessens the chance of spontaneous
>>combustion, but it doesn't prevent hot spots and it doesn't prevent
>>ignition so it has littly if any affect on pre-ignition.
>>
>>
>>Matt
>
>
> This is intended as an interesting dialog and learning exercise, not an
> argument!
>
> Since Octane rating explicitly affects the fuel's flash temperature, it
> certainly affects how hot a hot spot must be to cause a problem and does
> affect pre-ignition significantly.
>
> An interesting site that discusses octane and pre-ignition explicitly is
>
> http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
>
> "As you may have guessed from the earlier discussion of octane numbers,
> high octane fuels have a considerably higher auto ignition temperature to
> keep these pre-flame reactions from causing sudden uncontrolled pressure
> rises. If the charge burns fast enough or the fuel is resistant enough to
> auto ignition (high octane) then all is well and the pressure rise isn't
> too extreme." ... "We defined pre-ignition previously as the starting of
> the burning process by a source other than the plug"
Octane affects the auto-ignition temperature and the burn rate.
Pre-ignition is NOT auto ignition, that is the entire point. It is
simply ignition from a point source other than the spark plug. Keep
looking, maybe you can find a source that supports your assertion that
octane has a significant affect on pre-ignition, but I doubt it.
If it had a substantial affect on pre-ignition, it would also have a
substantial affect on regular ignition by the spark plug, and
suppressing such ignition in a spark ignition engine wouldn't be a very
good thing. :-)
Matt
> [original post is likely clipped to save bandwidth]
> On Sat, 28 Jan 2006 02:17:03 GMT, Matt Whiting <whiting@epix.net> wrote:
>
>
>>gerry wrote:
>>
>>
>>>Look up " detonate" in a good dictionary and you will find it is not as
>>>defined as used in the above reference! It is not "spontaneous
>>>combustion"!
>>>
>>>An example is
>>>
>>>http://www.yourdictionary.com/ahd/d/d0172500.html
>>>
>>>"To explode or cause to explode."
>>>
>>>http://en.wikipedia.org/wiki/Detonate
>>>
>>>states
>>>
>>>"involves a shock wave and a reaction zone behind it"
>>
>>Detonation used in the automotive sense isn't all that different. The
>>spontaneous combustion is in effect an explosion. That is what makes
>>all of the noise. It is the shock wave hitting the cylinder walls,
>>piston and head that makes the racket.
>>
>>
>>
>>
>>>Indeed one detonates a thermo nuclear weapon and that sure is not
>>>spontaneous combustion as defined in the reference you choose
>>>
>>>This is just to point out that different groups use different jargon. Thus
>>>I indicated not to worry too much about folks using different wording. I
>>>concede I use the words in more general engineering context, not
>>>automotive jargon.
>>
>>It makes sense to use automotive jargon when talking about an internal
>>combustion engine, which was the topic at hand.
>>
>>
>>
>>
>>>In context of this discussion and using your choice of wording, octane
>>>affects both "pre-ignition" and "detonation", inhibiting both.
>>
>>Octane inhibits detonation, but has almost no affect on pre-ignition.
>>Pre-ignition typically occurs from hot spots in the combustion chamber.
>> Octane slows down the burn rate and lessens the chance of spontaneous
>>combustion, but it doesn't prevent hot spots and it doesn't prevent
>>ignition so it has littly if any affect on pre-ignition.
>>
>>
>>Matt
>
>
> This is intended as an interesting dialog and learning exercise, not an
> argument!
>
> Since Octane rating explicitly affects the fuel's flash temperature, it
> certainly affects how hot a hot spot must be to cause a problem and does
> affect pre-ignition significantly.
>
> An interesting site that discusses octane and pre-ignition explicitly is
>
> http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
>
> "As you may have guessed from the earlier discussion of octane numbers,
> high octane fuels have a considerably higher auto ignition temperature to
> keep these pre-flame reactions from causing sudden uncontrolled pressure
> rises. If the charge burns fast enough or the fuel is resistant enough to
> auto ignition (high octane) then all is well and the pressure rise isn't
> too extreme." ... "We defined pre-ignition previously as the starting of
> the burning process by a source other than the plug"
Octane affects the auto-ignition temperature and the burn rate.
Pre-ignition is NOT auto ignition, that is the entire point. It is
simply ignition from a point source other than the spark plug. Keep
looking, maybe you can find a source that supports your assertion that
octane has a significant affect on pre-ignition, but I doubt it.
If it had a substantial affect on pre-ignition, it would also have a
substantial affect on regular ignition by the spark plug, and
suppressing such ignition in a spark ignition engine wouldn't be a very
good thing. :-)
Matt
01-29-2006, 02:14 PM
#77
Guest
Posts: n/a
Re: 87 octane '06 Sonata
[original post is likely clipped to save bandwidth]
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>gerry wrote:
>
>> [original post is likely clipped to save bandwidth]
>> On Sat, 28 Jan 2006 02:17:03 GMT, Matt Whiting <whiting@epix.net> wrote:
>>
>>
>>>gerry wrote:
>>>
>>>
>>>>Look up " detonate" in a good dictionary and you will find it is not as
>>>>defined as used in the above reference! It is not "spontaneous
>>>>combustion"!
>>>>
>>>>An example is
>>>>
>>>>http://www.yourdictionary.com/ahd/d/d0172500.html
>>>>
>>>>"To explode or cause to explode."
>>>>
>>>>http://en.wikipedia.org/wiki/Detonate
>>>>
>>>>states
>>>>
>>>>"involves a shock wave and a reaction zone behind it"
>>>
>>>Detonation used in the automotive sense isn't all that different. The
>>>spontaneous combustion is in effect an explosion. That is what makes
>>>all of the noise. It is the shock wave hitting the cylinder walls,
>>>piston and head that makes the racket.
>>>
>>>
>>>
>>>
>>>>Indeed one detonates a thermo nuclear weapon and that sure is not
>>>>spontaneous combustion as defined in the reference you choose
>>>>
>>>>This is just to point out that different groups use different jargon. Thus
>>>>I indicated not to worry too much about folks using different wording. I
>>>>concede I use the words in more general engineering context, not
>>>>automotive jargon.
>>>
>>>It makes sense to use automotive jargon when talking about an internal
>>>combustion engine, which was the topic at hand.
>>>
>>>
>>>
>>>
>>>>In context of this discussion and using your choice of wording, octane
>>>>affects both "pre-ignition" and "detonation", inhibiting both.
>>>
>>>Octane inhibits detonation, but has almost no affect on pre-ignition.
>>>Pre-ignition typically occurs from hot spots in the combustion chamber.
>>> Octane slows down the burn rate and lessens the chance of spontaneous
>>>combustion, but it doesn't prevent hot spots and it doesn't prevent
>>>ignition so it has littly if any affect on pre-ignition.
>>>
>>>
>>>Matt
>>
>>
>> This is intended as an interesting dialog and learning exercise, not an
>> argument!
>>
>> Since Octane rating explicitly affects the fuel's flash temperature, it
>> certainly affects how hot a hot spot must be to cause a problem and does
>> affect pre-ignition significantly.
>>
>> An interesting site that discusses octane and pre-ignition explicitly is
>>
>> http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
>>
>> "As you may have guessed from the earlier discussion of octane numbers,
>> high octane fuels have a considerably higher auto ignition temperature to
>> keep these pre-flame reactions from causing sudden uncontrolled pressure
>> rises. If the charge burns fast enough or the fuel is resistant enough to
>> auto ignition (high octane) then all is well and the pressure rise isn't
>> too extreme." ... "We defined pre-ignition previously as the starting of
>> the burning process by a source other than the plug"
>
>Octane affects the auto-ignition temperature and the burn rate.
>Pre-ignition is NOT auto ignition, that is the entire point. It is
>simply ignition from a point source other than the spark plug. Keep
>looking, maybe you can find a source that supports your assertion that
>octane has a significant affect on pre-ignition, but I doubt it.
I just posted that if you actually chose to read it. It appears you are
not interested in any discussion that doesn't meet your pre-conceived
ideas.
>If it had a substantial affect on pre-ignition, it would also have a
>substantial affect on regular ignition by the spark plug, and
>suppressing such ignition in a spark ignition engine wouldn't be a very
>good thing. :-)
Not at all, a spark temperature (from a spark plug) is commonly 60,000
Kelvin!!!! So dramatically far above the flash point of any useful fuel
air mixture the affect on spark induced ignition is thus nil.
gerry
--
Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>gerry wrote:
>
>> [original post is likely clipped to save bandwidth]
>> On Sat, 28 Jan 2006 02:17:03 GMT, Matt Whiting <whiting@epix.net> wrote:
>>
>>
>>>gerry wrote:
>>>
>>>
>>>>Look up " detonate" in a good dictionary and you will find it is not as
>>>>defined as used in the above reference! It is not "spontaneous
>>>>combustion"!
>>>>
>>>>An example is
>>>>
>>>>http://www.yourdictionary.com/ahd/d/d0172500.html
>>>>
>>>>"To explode or cause to explode."
>>>>
>>>>http://en.wikipedia.org/wiki/Detonate
>>>>
>>>>states
>>>>
>>>>"involves a shock wave and a reaction zone behind it"
>>>
>>>Detonation used in the automotive sense isn't all that different. The
>>>spontaneous combustion is in effect an explosion. That is what makes
>>>all of the noise. It is the shock wave hitting the cylinder walls,
>>>piston and head that makes the racket.
>>>
>>>
>>>
>>>
>>>>Indeed one detonates a thermo nuclear weapon and that sure is not
>>>>spontaneous combustion as defined in the reference you choose
>>>>
>>>>This is just to point out that different groups use different jargon. Thus
>>>>I indicated not to worry too much about folks using different wording. I
>>>>concede I use the words in more general engineering context, not
>>>>automotive jargon.
>>>
>>>It makes sense to use automotive jargon when talking about an internal
>>>combustion engine, which was the topic at hand.
>>>
>>>
>>>
>>>
>>>>In context of this discussion and using your choice of wording, octane
>>>>affects both "pre-ignition" and "detonation", inhibiting both.
>>>
>>>Octane inhibits detonation, but has almost no affect on pre-ignition.
>>>Pre-ignition typically occurs from hot spots in the combustion chamber.
>>> Octane slows down the burn rate and lessens the chance of spontaneous
>>>combustion, but it doesn't prevent hot spots and it doesn't prevent
>>>ignition so it has littly if any affect on pre-ignition.
>>>
>>>
>>>Matt
>>
>>
>> This is intended as an interesting dialog and learning exercise, not an
>> argument!
>>
>> Since Octane rating explicitly affects the fuel's flash temperature, it
>> certainly affects how hot a hot spot must be to cause a problem and does
>> affect pre-ignition significantly.
>>
>> An interesting site that discusses octane and pre-ignition explicitly is
>>
>> http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
>>
>> "As you may have guessed from the earlier discussion of octane numbers,
>> high octane fuels have a considerably higher auto ignition temperature to
>> keep these pre-flame reactions from causing sudden uncontrolled pressure
>> rises. If the charge burns fast enough or the fuel is resistant enough to
>> auto ignition (high octane) then all is well and the pressure rise isn't
>> too extreme." ... "We defined pre-ignition previously as the starting of
>> the burning process by a source other than the plug"
>
>Octane affects the auto-ignition temperature and the burn rate.
>Pre-ignition is NOT auto ignition, that is the entire point. It is
>simply ignition from a point source other than the spark plug. Keep
>looking, maybe you can find a source that supports your assertion that
>octane has a significant affect on pre-ignition, but I doubt it.
I just posted that if you actually chose to read it. It appears you are
not interested in any discussion that doesn't meet your pre-conceived
ideas.
>If it had a substantial affect on pre-ignition, it would also have a
>substantial affect on regular ignition by the spark plug, and
>suppressing such ignition in a spark ignition engine wouldn't be a very
>good thing. :-)
Not at all, a spark temperature (from a spark plug) is commonly 60,000
Kelvin!!!! So dramatically far above the flash point of any useful fuel
air mixture the affect on spark induced ignition is thus nil.
gerry
--
Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
01-29-2006, 02:14 PM
#78
Guest
Posts: n/a
Re: 87 octane '06 Sonata
[original post is likely clipped to save bandwidth]
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>gerry wrote:
>
>> [original post is likely clipped to save bandwidth]
>> On Sat, 28 Jan 2006 02:17:03 GMT, Matt Whiting <whiting@epix.net> wrote:
>>
>>
>>>gerry wrote:
>>>
>>>
>>>>Look up " detonate" in a good dictionary and you will find it is not as
>>>>defined as used in the above reference! It is not "spontaneous
>>>>combustion"!
>>>>
>>>>An example is
>>>>
>>>>http://www.yourdictionary.com/ahd/d/d0172500.html
>>>>
>>>>"To explode or cause to explode."
>>>>
>>>>http://en.wikipedia.org/wiki/Detonate
>>>>
>>>>states
>>>>
>>>>"involves a shock wave and a reaction zone behind it"
>>>
>>>Detonation used in the automotive sense isn't all that different. The
>>>spontaneous combustion is in effect an explosion. That is what makes
>>>all of the noise. It is the shock wave hitting the cylinder walls,
>>>piston and head that makes the racket.
>>>
>>>
>>>
>>>
>>>>Indeed one detonates a thermo nuclear weapon and that sure is not
>>>>spontaneous combustion as defined in the reference you choose
>>>>
>>>>This is just to point out that different groups use different jargon. Thus
>>>>I indicated not to worry too much about folks using different wording. I
>>>>concede I use the words in more general engineering context, not
>>>>automotive jargon.
>>>
>>>It makes sense to use automotive jargon when talking about an internal
>>>combustion engine, which was the topic at hand.
>>>
>>>
>>>
>>>
>>>>In context of this discussion and using your choice of wording, octane
>>>>affects both "pre-ignition" and "detonation", inhibiting both.
>>>
>>>Octane inhibits detonation, but has almost no affect on pre-ignition.
>>>Pre-ignition typically occurs from hot spots in the combustion chamber.
>>> Octane slows down the burn rate and lessens the chance of spontaneous
>>>combustion, but it doesn't prevent hot spots and it doesn't prevent
>>>ignition so it has littly if any affect on pre-ignition.
>>>
>>>
>>>Matt
>>
>>
>> This is intended as an interesting dialog and learning exercise, not an
>> argument!
>>
>> Since Octane rating explicitly affects the fuel's flash temperature, it
>> certainly affects how hot a hot spot must be to cause a problem and does
>> affect pre-ignition significantly.
>>
>> An interesting site that discusses octane and pre-ignition explicitly is
>>
>> http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
>>
>> "As you may have guessed from the earlier discussion of octane numbers,
>> high octane fuels have a considerably higher auto ignition temperature to
>> keep these pre-flame reactions from causing sudden uncontrolled pressure
>> rises. If the charge burns fast enough or the fuel is resistant enough to
>> auto ignition (high octane) then all is well and the pressure rise isn't
>> too extreme." ... "We defined pre-ignition previously as the starting of
>> the burning process by a source other than the plug"
>
>Octane affects the auto-ignition temperature and the burn rate.
>Pre-ignition is NOT auto ignition, that is the entire point. It is
>simply ignition from a point source other than the spark plug. Keep
>looking, maybe you can find a source that supports your assertion that
>octane has a significant affect on pre-ignition, but I doubt it.
I just posted that if you actually chose to read it. It appears you are
not interested in any discussion that doesn't meet your pre-conceived
ideas.
>If it had a substantial affect on pre-ignition, it would also have a
>substantial affect on regular ignition by the spark plug, and
>suppressing such ignition in a spark ignition engine wouldn't be a very
>good thing. :-)
Not at all, a spark temperature (from a spark plug) is commonly 60,000
Kelvin!!!! So dramatically far above the flash point of any useful fuel
air mixture the affect on spark induced ignition is thus nil.
gerry
--
Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>gerry wrote:
>
>> [original post is likely clipped to save bandwidth]
>> On Sat, 28 Jan 2006 02:17:03 GMT, Matt Whiting <whiting@epix.net> wrote:
>>
>>
>>>gerry wrote:
>>>
>>>
>>>>Look up " detonate" in a good dictionary and you will find it is not as
>>>>defined as used in the above reference! It is not "spontaneous
>>>>combustion"!
>>>>
>>>>An example is
>>>>
>>>>http://www.yourdictionary.com/ahd/d/d0172500.html
>>>>
>>>>"To explode or cause to explode."
>>>>
>>>>http://en.wikipedia.org/wiki/Detonate
>>>>
>>>>states
>>>>
>>>>"involves a shock wave and a reaction zone behind it"
>>>
>>>Detonation used in the automotive sense isn't all that different. The
>>>spontaneous combustion is in effect an explosion. That is what makes
>>>all of the noise. It is the shock wave hitting the cylinder walls,
>>>piston and head that makes the racket.
>>>
>>>
>>>
>>>
>>>>Indeed one detonates a thermo nuclear weapon and that sure is not
>>>>spontaneous combustion as defined in the reference you choose
>>>>
>>>>This is just to point out that different groups use different jargon. Thus
>>>>I indicated not to worry too much about folks using different wording. I
>>>>concede I use the words in more general engineering context, not
>>>>automotive jargon.
>>>
>>>It makes sense to use automotive jargon when talking about an internal
>>>combustion engine, which was the topic at hand.
>>>
>>>
>>>
>>>
>>>>In context of this discussion and using your choice of wording, octane
>>>>affects both "pre-ignition" and "detonation", inhibiting both.
>>>
>>>Octane inhibits detonation, but has almost no affect on pre-ignition.
>>>Pre-ignition typically occurs from hot spots in the combustion chamber.
>>> Octane slows down the burn rate and lessens the chance of spontaneous
>>>combustion, but it doesn't prevent hot spots and it doesn't prevent
>>>ignition so it has littly if any affect on pre-ignition.
>>>
>>>
>>>Matt
>>
>>
>> This is intended as an interesting dialog and learning exercise, not an
>> argument!
>>
>> Since Octane rating explicitly affects the fuel's flash temperature, it
>> certainly affects how hot a hot spot must be to cause a problem and does
>> affect pre-ignition significantly.
>>
>> An interesting site that discusses octane and pre-ignition explicitly is
>>
>> http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
>>
>> "As you may have guessed from the earlier discussion of octane numbers,
>> high octane fuels have a considerably higher auto ignition temperature to
>> keep these pre-flame reactions from causing sudden uncontrolled pressure
>> rises. If the charge burns fast enough or the fuel is resistant enough to
>> auto ignition (high octane) then all is well and the pressure rise isn't
>> too extreme." ... "We defined pre-ignition previously as the starting of
>> the burning process by a source other than the plug"
>
>Octane affects the auto-ignition temperature and the burn rate.
>Pre-ignition is NOT auto ignition, that is the entire point. It is
>simply ignition from a point source other than the spark plug. Keep
>looking, maybe you can find a source that supports your assertion that
>octane has a significant affect on pre-ignition, but I doubt it.
I just posted that if you actually chose to read it. It appears you are
not interested in any discussion that doesn't meet your pre-conceived
ideas.
>If it had a substantial affect on pre-ignition, it would also have a
>substantial affect on regular ignition by the spark plug, and
>suppressing such ignition in a spark ignition engine wouldn't be a very
>good thing. :-)
Not at all, a spark temperature (from a spark plug) is commonly 60,000
Kelvin!!!! So dramatically far above the flash point of any useful fuel
air mixture the affect on spark induced ignition is thus nil.
gerry
--
Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
01-29-2006, 02:14 PM
#79
Guest
Posts: n/a
Re: 87 octane '06 Sonata
[original post is likely clipped to save bandwidth]
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>gerry wrote:
>
>> [original post is likely clipped to save bandwidth]
>> On Sat, 28 Jan 2006 02:17:03 GMT, Matt Whiting <whiting@epix.net> wrote:
>>
>>
>>>gerry wrote:
>>>
>>>
>>>>Look up " detonate" in a good dictionary and you will find it is not as
>>>>defined as used in the above reference! It is not "spontaneous
>>>>combustion"!
>>>>
>>>>An example is
>>>>
>>>>http://www.yourdictionary.com/ahd/d/d0172500.html
>>>>
>>>>"To explode or cause to explode."
>>>>
>>>>http://en.wikipedia.org/wiki/Detonate
>>>>
>>>>states
>>>>
>>>>"involves a shock wave and a reaction zone behind it"
>>>
>>>Detonation used in the automotive sense isn't all that different. The
>>>spontaneous combustion is in effect an explosion. That is what makes
>>>all of the noise. It is the shock wave hitting the cylinder walls,
>>>piston and head that makes the racket.
>>>
>>>
>>>
>>>
>>>>Indeed one detonates a thermo nuclear weapon and that sure is not
>>>>spontaneous combustion as defined in the reference you choose
>>>>
>>>>This is just to point out that different groups use different jargon. Thus
>>>>I indicated not to worry too much about folks using different wording. I
>>>>concede I use the words in more general engineering context, not
>>>>automotive jargon.
>>>
>>>It makes sense to use automotive jargon when talking about an internal
>>>combustion engine, which was the topic at hand.
>>>
>>>
>>>
>>>
>>>>In context of this discussion and using your choice of wording, octane
>>>>affects both "pre-ignition" and "detonation", inhibiting both.
>>>
>>>Octane inhibits detonation, but has almost no affect on pre-ignition.
>>>Pre-ignition typically occurs from hot spots in the combustion chamber.
>>> Octane slows down the burn rate and lessens the chance of spontaneous
>>>combustion, but it doesn't prevent hot spots and it doesn't prevent
>>>ignition so it has littly if any affect on pre-ignition.
>>>
>>>
>>>Matt
>>
>>
>> This is intended as an interesting dialog and learning exercise, not an
>> argument!
>>
>> Since Octane rating explicitly affects the fuel's flash temperature, it
>> certainly affects how hot a hot spot must be to cause a problem and does
>> affect pre-ignition significantly.
>>
>> An interesting site that discusses octane and pre-ignition explicitly is
>>
>> http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
>>
>> "As you may have guessed from the earlier discussion of octane numbers,
>> high octane fuels have a considerably higher auto ignition temperature to
>> keep these pre-flame reactions from causing sudden uncontrolled pressure
>> rises. If the charge burns fast enough or the fuel is resistant enough to
>> auto ignition (high octane) then all is well and the pressure rise isn't
>> too extreme." ... "We defined pre-ignition previously as the starting of
>> the burning process by a source other than the plug"
>
>Octane affects the auto-ignition temperature and the burn rate.
>Pre-ignition is NOT auto ignition, that is the entire point. It is
>simply ignition from a point source other than the spark plug. Keep
>looking, maybe you can find a source that supports your assertion that
>octane has a significant affect on pre-ignition, but I doubt it.
I just posted that if you actually chose to read it. It appears you are
not interested in any discussion that doesn't meet your pre-conceived
ideas.
>If it had a substantial affect on pre-ignition, it would also have a
>substantial affect on regular ignition by the spark plug, and
>suppressing such ignition in a spark ignition engine wouldn't be a very
>good thing. :-)
Not at all, a spark temperature (from a spark plug) is commonly 60,000
Kelvin!!!! So dramatically far above the flash point of any useful fuel
air mixture the affect on spark induced ignition is thus nil.
gerry
--
Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>gerry wrote:
>
>> [original post is likely clipped to save bandwidth]
>> On Sat, 28 Jan 2006 02:17:03 GMT, Matt Whiting <whiting@epix.net> wrote:
>>
>>
>>>gerry wrote:
>>>
>>>
>>>>Look up " detonate" in a good dictionary and you will find it is not as
>>>>defined as used in the above reference! It is not "spontaneous
>>>>combustion"!
>>>>
>>>>An example is
>>>>
>>>>http://www.yourdictionary.com/ahd/d/d0172500.html
>>>>
>>>>"To explode or cause to explode."
>>>>
>>>>http://en.wikipedia.org/wiki/Detonate
>>>>
>>>>states
>>>>
>>>>"involves a shock wave and a reaction zone behind it"
>>>
>>>Detonation used in the automotive sense isn't all that different. The
>>>spontaneous combustion is in effect an explosion. That is what makes
>>>all of the noise. It is the shock wave hitting the cylinder walls,
>>>piston and head that makes the racket.
>>>
>>>
>>>
>>>
>>>>Indeed one detonates a thermo nuclear weapon and that sure is not
>>>>spontaneous combustion as defined in the reference you choose
>>>>
>>>>This is just to point out that different groups use different jargon. Thus
>>>>I indicated not to worry too much about folks using different wording. I
>>>>concede I use the words in more general engineering context, not
>>>>automotive jargon.
>>>
>>>It makes sense to use automotive jargon when talking about an internal
>>>combustion engine, which was the topic at hand.
>>>
>>>
>>>
>>>
>>>>In context of this discussion and using your choice of wording, octane
>>>>affects both "pre-ignition" and "detonation", inhibiting both.
>>>
>>>Octane inhibits detonation, but has almost no affect on pre-ignition.
>>>Pre-ignition typically occurs from hot spots in the combustion chamber.
>>> Octane slows down the burn rate and lessens the chance of spontaneous
>>>combustion, but it doesn't prevent hot spots and it doesn't prevent
>>>ignition so it has littly if any affect on pre-ignition.
>>>
>>>
>>>Matt
>>
>>
>> This is intended as an interesting dialog and learning exercise, not an
>> argument!
>>
>> Since Octane rating explicitly affects the fuel's flash temperature, it
>> certainly affects how hot a hot spot must be to cause a problem and does
>> affect pre-ignition significantly.
>>
>> An interesting site that discusses octane and pre-ignition explicitly is
>>
>> http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
>>
>> "As you may have guessed from the earlier discussion of octane numbers,
>> high octane fuels have a considerably higher auto ignition temperature to
>> keep these pre-flame reactions from causing sudden uncontrolled pressure
>> rises. If the charge burns fast enough or the fuel is resistant enough to
>> auto ignition (high octane) then all is well and the pressure rise isn't
>> too extreme." ... "We defined pre-ignition previously as the starting of
>> the burning process by a source other than the plug"
>
>Octane affects the auto-ignition temperature and the burn rate.
>Pre-ignition is NOT auto ignition, that is the entire point. It is
>simply ignition from a point source other than the spark plug. Keep
>looking, maybe you can find a source that supports your assertion that
>octane has a significant affect on pre-ignition, but I doubt it.
I just posted that if you actually chose to read it. It appears you are
not interested in any discussion that doesn't meet your pre-conceived
ideas.
>If it had a substantial affect on pre-ignition, it would also have a
>substantial affect on regular ignition by the spark plug, and
>suppressing such ignition in a spark ignition engine wouldn't be a very
>good thing. :-)
Not at all, a spark temperature (from a spark plug) is commonly 60,000
Kelvin!!!! So dramatically far above the flash point of any useful fuel
air mixture the affect on spark induced ignition is thus nil.
gerry
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01-29-2006, 02:25 PM
#80
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Re: 87 octane '06 Sonata
[original post is likely clipped to save bandwidth]
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>Octane affects the auto-ignition temperature and the burn rate.
"It's a commonly held misconception that higher Octane fuel slows down the
flame speed"
from http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
gerry
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Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>Octane affects the auto-ignition temperature and the burn rate.
"It's a commonly held misconception that higher Octane fuel slows down the
flame speed"
from http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
gerry
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Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
01-29-2006, 02:25 PM
#81
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Re: 87 octane '06 Sonata
[original post is likely clipped to save bandwidth]
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>Octane affects the auto-ignition temperature and the burn rate.
"It's a commonly held misconception that higher Octane fuel slows down the
flame speed"
from http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
gerry
--
Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>Octane affects the auto-ignition temperature and the burn rate.
"It's a commonly held misconception that higher Octane fuel slows down the
flame speed"
from http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
gerry
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Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
01-29-2006, 02:25 PM
#82
Guest
Posts: n/a
Re: 87 octane '06 Sonata
[original post is likely clipped to save bandwidth]
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>Octane affects the auto-ignition temperature and the burn rate.
"It's a commonly held misconception that higher Octane fuel slows down the
flame speed"
from http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
gerry
--
Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
On Sun, 29 Jan 2006 18:56:12 GMT, Matt Whiting <whiting@epix.net> wrote:
>Octane affects the auto-ignition temperature and the burn rate.
"It's a commonly held misconception that higher Octane fuel slows down the
flame speed"
from http://www.eric-gorr.com/techarticles/Fuel_Basics.htm
gerry
--
Personal home page - http://gogood.com
gerry misspelled in my email address to confuse robots
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