the apparent magic of detonation

[CoyoteX]

Mach #
The 1979 SAE (Society of Automotive Engineers) paper "An Analysis of the Volumetric Efficiency Characteristics of 4-Stroke
Cycle Engines Using the Mean Inlet Mach Number, Mim", 790484, by Fukutani and Watanabe is the basis of this calculation.
(C) Performance Trends Inc 1997 Engine Analyzer Pro Chapter 2 Definitions
83
It was an extension of the Mach Index characteristic first identified in the 1940s by C.F. Taylor and co-workers from MIT,
"The Internal Combustion Engine In Theory and Practice", C.F. Taylor, 1985, MIT Press.
These papers state that an engine's air flow potential per cycle (volumetric efficiency) depends on its average intake flow
coefficient, intake valve flow area, cylinder size, speed of sound in air and RPM. These five terms are combined into one value
called the Mach Index, called Mach # by the Engine Analyzer Pro. In simple terms Mach # relates the average velocity of the
intake charge past the valve to the speed of sound. The speed of sound is theoretically the maximum velocity possible past the
valve, which would give a Mach # of 1.0. A Mach # of .4 states the average velocity is only 40% of the maximum possible
velocity.
Taylor's work showed good correlation between volumetric efficiency and Mach # for several engines with conservative cam
timing. The correlation showed that volumetric efficiency (and therefore power) would start to drop sharply when Mach #
increased above approximately .55. However, more recent studies show poor correlation if intake cam duration increases
significantly. The 1979 paper includes a correction for intake duration; the higher the intake duration, the lower the Mach #,
and the higher the RPM for peak volumetric efficiency.
General "rules of thumb" concerning the Mach # include:
? Peak volumetric efficiency should occur in the range of .3 to .5 Mach # with no tuning effects
? Volumetric efficiency drops rapidly in the range of .6 - .8 Mach #
The Mach # is calculated based on the static intake valve flow area, not dynamic flow area which can be different due to valve
train bending or tossing. See Act In FlowArea,%. The Engine Analyzer Pro does not use Mach # in its calculations, but
reports it only for information.

this is from the engine analyzer pro instruction manual It is a pretty nice program for understanding what is going on in an engine. The demo is enough to play with and get an idea of what would help power in the range you care about for your engine. increasing VE for 1500-3000 or whatever rpm range you need is what you would be mainly concerned with in that program though.

[ShadowWorks]

This is a very interesting thread, may I mix it.

I think Molecule is on to something but I don't know what myself, I agree with the posters that detonation looks simple if you read the text book, its an uncontrolled explosion of fuel which is not turned into mechanical energy and is sent into the piston as heat and it melts.

Well here is a brain bone for you guys, I am suggesting that the electrical spark in the gap is conducted through the "Detonation wave" and converted into a plasma which is far hotter than a hydro carbon fuel.

The electrical energy from the spark does not just jump the gap to burn the fuel, when the conditions are right it will fuse and become the flame front but as a Plasma Arc which our metal engines can do nothing with.

Ok so if a electrical spark can fuse to become plasma because of the pressure how can we get a 100% fuel burn without making an electrical plasma?

Answer

Pulse Width Microwave Technology, no need for a Sparking electricity GAP, just a resonant frequency that can only ignite fuel, impossible to get detonation and impossible to leave any fuel behind.

It is interesting to note that petrol engines make huge electrical garbage in the RF range, Diesels do not, diesel have no spark plugs

[Rayme]

Originally Posted by ShadowWorks

This is a very interesting thread, may I mix it.

I think Molecule is on to something but I don't know what myself, I agree with the posters that detonation looks simple if you read the text book, its an uncontrolled explosion of fuel which is not turned into mechanical energy and is sent into the piston as heat and it melts.

Well here is a brain bone for you guys, I am suggesting that the electrical spark in the gap is conducted through the "Detonation wave" and converted into a plasma which is far hotter than a hydro carbon fuel.

The electrical energy from the spark does not just jump the gap to burn the fuel, when the conditions are right it will fuse and become the flame front but as a Plasma Arc which our metal engines can do nothing with.

Ok so if a electrical spark can fuse to become plasma because of the pressure how can we get a 100% fuel burn without making an electrical plasma?

Answer

Pulse Width Microwave Technology, no need for a Sparking electricity GAP, just a resonant frequency that can only ignite fuel, impossible to get detonation and impossible to leave any fuel behind.

It is interesting to note that petrol engines make huge electrical garbage in the RF range, Diesels do not, diesel have no spark plugs

Way to wake an old thread!

I'm not sure what you were saying..detonation has nothing to with the spark plug, so why would a Pulse Width Microwave cure detonation? The best way to control detonation is simple (like in diesel), just inject the fuel when it's supposed to burn(direct injection). Fuel not burning efficiently is more related to not being atomised efficiently rather than what ignites it, thus why gas fuel (like propane) burn much MUCH more efficiently and completely.

[ShadowWorks]

Originally Posted by Rayme

Way to wake an old thread!

Thanks

Originally Posted by Rayme

I'm not sure what you were saying..detonation has nothing to with the spark plug, so why would a Pulse Width Microwave cure detonation?

It would provide total fuel burn regardless of how well or badly it had vaporised, the microwave pulse would be 100% varaible and would ECU controlled for best use.

[/QUOTE]The best way to control detonation is simple (like in diesel), just inject the fuel when it's supposed to burn(direct injection)[/QUOTE]

Diesel is like 170 ron? something high like that right?

I am not sure petrol would work with direct injection or else they or somebody would have done it by now? is that fair to say?

You know maybe Smokey Vapour engine used some kind of detonation instead of burn? I think there is more power in the detonation then in the burn process.

[GasSavers_Glacial]

My hat is off to molecule.

Greatest troll evar.

[R.I.D.E.]

If the air fuel mix is perfectly homogenous (HCCI) then the fuel air mix can ignite simultaneously using compression alone. There is no flame front and no spark is necessary. This is using gasoline as fuel. The potential is a 25% increase in efficiency, gasoline engines would be close to the same efficiency as diesel and post combustion emissions treatment would be unnecessary, even though the mixture would be much leaner than current engines.

Smokey was working on this idea and understood that it took time for the fuel air mix to be thoroughly homogenized. Much harder to accomplish this with port fuel injection, with the danger of the mix igniting in the chamber where it is becoming homogenized.

Detonation is much different. In reloading ammunition for guns, detonation is a potential disaster when you use less than full volume charges in the case. The possibility of the powder being in the front of the case at the point of ignition with the resulting pressure wave moving to the rear of the case can wreck a modern firearm built to withstand much greater pressures than a combustion chamber in an engine.

Generally detonation (preignition) is caused by poor fuel air mixture creating spots that ignite before other parts of the fuel air mixture, when the resulting pressure waves converge you have detonation. Instead of pushing the piston down with a fairly consistent increase in pressure, the combustion occurs much quicker with the pressure wave slamming the piston with much higher pressures very quickly.


regards
gary

[ShadowWorks]

I know detonation would destroy a conventional or even high performance petrol engine, But I though diesel engines work by using knock?, that is why they put out the wooden duga duga duga sound

How robust would an engine have to be to utilise knock instead of burn?

I mean we agree there is some kind of short term hyper explosion with super heat and pressure, now if they could find a way to convert that energy which probably has more potential? who knows?

[dosco]

Originally Posted by Glacial

My hat is off to molecule.

Greatest troll evar.

No. He's far too calm. Try some of the fitness boards for "fun trolls."

[DarbyWalters]

quit...typing with...morse code...!
and using some kinda of poetic beat...
it indicates that pre detonation occurred...
in your bedroom and it...is time...to put out the blunt...!

[Rayme]

The turbocharged Mazdaspeed3 uses direct injection, and so is the new turbocharged Ecotec in the Cobalt...and GM is going to introduce another..turbocharged! Small engine in the future (sub 2.0). It does make the fuel burn better, to can get away with better MPG and Emission !

Now I don't know how exactly direct injection works, (does it gets injected right before the sparks, or while the intake valves open?), so I don't know how good it is at detering knock, I didn't read much on the subject to be fair.

Originally Posted by ShadowWorks

Thanks



It would provide total fuel burn regardless of how well or badly it had vaporised, the microwave pulse would be 100% varaible and would ECU controlled for best use.

The best way to control detonation is simple (like in diesel), just inject the fuel when it's supposed to burn(direct injection)[/QUOTE]

Diesel is like 170 ron? something high like that right?

I am not sure petrol would work with direct injection or else they or somebody would have done it by now? is that fair to say?

You know maybe Smokey Vapour engine used some kind of detonation instead of burn? I think there is more power in the detonation then in the burn process.[/QUOTE]