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Diesel smoke modeling Are there any laws (have to be)? Rate Topic: -----

#11 User is online   Weter 

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Posted 15 November 2020 - 08:22 AM

Do You mean, the loco behaves different (performance) in activities, or it even fails to load to MSTS AE?
You shown me very interesting topic, thanks again.

But wich of that parameters defines the smoke jet's height?

#12 User is offline   Lamplighter 

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Posted 16 November 2020 - 12:45 AM

MSTS AE cannot load some Open Rails parameters. I can't describe it exactly. I don't do activities.
I know from our national MSTS / ORTS discussion forum that "activists" prefer to work with MS Activity Editor. He probably can do something extra.
But it has problems loading .eng and .wag files set purely for OR.

There is no special parameter for determining the height of smoke. It only works with its dynamics.
I would try to work with the values of the following parameters:
IdleExhaust ( 4 )
MaxExhaust ( 11 )
ExhaustDynamics ( 1.2 )
ExhaustDynamicsDown ( 0.5 )


#13 User is online   Weter 

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Posted 16 November 2020 - 02:45 PM

I have noted, that the size of nozzle, determined in 3-rd row of the diesel speshial effects() block somehow indirectly influences to the height of smoke jet, but how?
As I don't see the program code, the formulas and algorithm of smoke producing remains in darkness for me, as the documentation of that never be seen anywhere by myself.
Next time I'll likeny try to comment-out the whole MSTS DieselSmokeEffect section, as You suggest, and compare an outcomes.

Yes, I noted, that MSTS AE have "suddenly" unaccept some *eng-file's strings, issuing warning dialogue-tabs during trains folder listing (every time at start, or before new consist creation) did You mean that.

#14 User is offline   Lamplighter 

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Posted 17 November 2020 - 12:04 AM

Example:

Exhaust1 (
-0.65 --> Position X (from the central point)
4.6 --> Position Y (from the central point)
1.5 --> Position Z (from the central point)
0 --> The direction of the effect in the X axis (0=no, 1=yes)
1 --> The direction of the effect in the X axis
0 --> The direction of the effect in the X axis
0.2 --> Size of the exhaust nozzle in metres
)
)

The combination of XYZ directions creates the appropriate angle.
Very nicely and in detail it is described by Steamer_ctn here. And a lot more.

#15 User is online   Weter 

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Posted 17 November 2020 - 07:28 AM

Thank you for link!

Yes, I feel myself quite familiar with that block, editing *eng-files about 18 years, and I noted, that the last parameter (0,2 at your example) has influence on jet height.
If I refer, say 0,02 (2cm) nozzle (useful to adjust smoke's origin position with model*), then the height may be some meters! Did you ever try such "perversions"?
The significant shift on smoke height behavior happens some around 0.15-0,20m (it turns more calm) but I can't increase the diameter too much as I have to match the funnel size.

Quote

The combination of XYZ directions creates the appropriate angle.

Again, I would like to obtain formulas, because without them, the tilting of smoke jets is just experimental and wastes plenty of precious time.
Oh, I've just found an angle calculator for direction of smoke/steam at Peter Newell's site, thanks again!

As for MSTS AE incompatibility, does include technology help to avoid such issues?

________
* it's quite simpler to use S-Viewer to adjust positions is smoke and light effects, but I've learn it only this year

#16 User is online   Weter 

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Posted 17 November 2020 - 12:34 PM

As soon as I've not yet experimented with settings, offered by Lamplighter here, the only question a can ask at this moment is:
It seems a lack of smoke effect parameter,referring the exhaust gas pressure min/max and, so far-the height of smoke jet.

#17 User is online   Weter 

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Posted 04 November 2022 - 10:45 PM

Well, some research results:

First, let's take in account, that diesel smoke is being produced as a sequence of elementary "clouds".
These clouds are "frames" of dieselsmoke.ace transparent texture. It contains 4x4=16 frames with different form of smoke. As we know, it's color code shouldn't contain "zero" components, because for alternating smoke's color, the Program multiplies these numbers with some factor, but multiplication zero by anything will result always zeros.
It would be essential to know, whether transparency (alpha channel) number altered by program, or not.


Then, these clouds are being spawned at specified in "smoke effect" block place(s), having initial size, given at the same block.
As we know, block refers coordinates of said place, direction of a smoke jet and it's initial size.
The number of clouds, spawned per second is believed to be referred by "smoke rate" parameter; so later, I'll tell my thoughts about how to adapt it to concrete locomotives.

1. SMOKE MAGNITUDE is seemed to be the "lifetime" of elementary clouds, in seconds.
Lower the magnitude, faster smoke cloud will dissipate in the air.
I guess, this is where transparency alternation works. But what about expansion speed?
If one wants the smoke to persist for longer time, magnitude should be increased.
If diesel is in good condition, magnitude should be lowered, to show "less" smoke amount.
Again, it would be done the better way by initial transparency control possibility.

Side notes:
-Lower-specification PC's can freeze, if too much "smoke clouds" are displayed simultaneously.
-MSTS specification of magnitude will be enormous in ORTS, so some adjustments have to be done.

2. SMOKE RATE
With 2-stroke engines works well and simple: following ErickC's assumption, that engine "puffs" as many of smoke "clouds" per second, as it makes revolutions, the only thing we need - is to calculate the number of revolutions per second; for what, we divide rpm by 60. Minimal and maximal rpm are given in nearby block of the eng-file. So, we'll get minimal and maximal smoke rate soon. For instance, 600rpm is equivalent to 10 rps.
With four-stroke, things are more unclear. As "puff" occurs on every second revolution, we should divide rpm number by 120. But more bad thing, that exhaust gases have lower pressure, and acoustic suppressors are often used, so "rate" will seem to be lower.
Yes, ORTS gives transient rate as an addition to "idle" and maximal", but it doesn't covers the question's subject.

3. Three unclear things
-expansion rate of smoke "clouds" and
-pressure (speed) of their movement.
Second one depends somehow (what affects the jet's height too) on nozzle's size, given in "smoke effects" block.
First is tied with it too, or maybe only appears in correspondence with magnitude.
-jet's maximal height:
It seems, in absence of MSTS - implemented smoke collision with obstacles as tunnel's ceiling, or overpass bridges, ORTS has some "height limitation" of the smoke rising: it can't go higher in any case. So, all further smoke "expansion" will take place in limited height, as "cloud" have reached that height.

So, it's better to ask someone to see the code for smoke generation (particle emission) formulae for telling exact law of the process.

#18 User is online   Laci1959 

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Posted 05 November 2022 - 01:27 AM

Hello.

The best solution is to use the ORTSDieselEngines block. If you are not a train driver, it is sometimes difficult to obtain information.
IdleExhaust (1.8) comment (Amount of idle smoke)
MaxExhaust (16.0) comment (the amount of smoke associated with maximum speed)
ExhaustDynamics (8.0) comment (Idle smoke dynamics)
ExhaustDynamicsDown (4.0) comment (dynamics of smoke at maximum speed)
ExhaustColor (00CACACA) comment (Idle smoke color)
ExhaustTransientColor comment (smoke color for maximum speed)

I can't do much with the dynamics due to translation problems. Smoke colors must be entered in HEXA code. There is a program for this on the Internet. The first two numbers are transparency.
From the old parameters, only the line Exhaust1 ( 0 4.5 2.8 0 1 0 0.32 ) is used by the OR if there is an ORTSDieselEngines block. The higher the last number, the higher the smoke starts to spread. I usually use values ​​between 0.1 and 0.3.
The value of MaxExhaust ( ) depends on the type. with the M62 Sergej, I don't usually skimp on it.
What is still needed is the MaxDieselLevel parameter. This is the amount of fuel that can be filled in the fuel tank in liters.

	MaxDieselLevel ( 4100l )
Comment ( **
	DieselUsedPerHourAtMaxPower ( 448l )
	DieselUsedPerHourAtIdle ( 34.7l )

	DieselSmokeEffectInitialMagnitude ( 2.4 )
	DieselSmokeEffectMaxMagnitude ( 2.5 )
	DieselSmokeEffectInitialSmokeRate ( 2.4 )
	DieselSmokeEffectMaxSmokeRate ( 18 )

	DieselEngineIdleRPM ( 250 )
	DieselEngineMaxRPM ( 750 )
	DieselEngineMaxRPMChangeRate ( 60 )
	DieselEngineSpeedOfMaxTractiveEffort ( 21km/h )
** )

The code snippet above shows the removal of unused MSTS parameters. I didn't delete it, I just commented it. They are not needed due to the use of the ORTSDieselEngines block.

Two videos on the effect of the smoke setting.
Governancek
My link

The first two pictures show smoke at idling speed and rising speed. At idle, the transparency is set to maximum, in the other image there is no transparency.
https://kephost.net/p/2022/44/4364_6a990a55ab6e.png

https://kephost.net/p/2022/44/3844_8f0e8bcb7866.png

Three locomotives, three different settings.
https://kephost.net/p/2022/44/4071_7faa50a26272.png

https://kephost.net/p/2022/17/7443_b0be69916aaf.png

Finally, some pictures of the effects of the settings.
What I think is a big mistake is that when the engine is set to maximum speed, the smoke turns white. With some tpus, this is not a real sight.

Sincerely, Laci 1959

#19 User is online   Weter 

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Posted 05 November 2022 - 01:41 AM

I'd say the next way:
ORTSDiesel () block is good to have as an include code for all locomotives, using such diesel.
As one obtain more accurate parameters and enters them, all locomotives will be improved automatically then.
There will be rpm, fuel consumption, torque, temperature, etc. tabs and BASIC/COMMON smoke characteristics. For all locomotives.

In individual locomotive, it's needed to refer the place and shape of exhaust outlet:
- (old M62 had two funnels, no suppressor), they called taigatrommel in Germany, You've heared it's rumble, I emember.
- "Classic" M62 had suppressor with narrow (3 or even 4 jets are needed) outlet at front, while
- M62y (ДМ62, or 2M62y) had different suppressor with elliptic outlet (1 or 2 jets would be enough) at the rear end. (Thought, there is 14Д40у diesel there, instead of 14Д40)

As well, engines in good condition produce less of smoke, and it's clearer, than long-time worn ones. Furthermore, if oil squeezed in combustion cameras, smoke turns blueish or white. I guess, old parameters are mixed with ORTS and can alter them. For particular engine.

Smoke, turning white during notching-down is none-prototypic indeed.
Instead, it should be more transparent at that period.

#20 User is online   Weter 

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Posted 05 November 2022 - 01:58 AM

Quote

The higher the last number, the higher the smoke starts to spread. I usually use values ​​between 0.1 and 0.3.

Do You mean outlet's diameter? Yes, from thin holes, the smoke runs higher. I've noticed that in my post above, but there is a height-limit (see the same post)

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