Annotated ORTS Diesel Engine Block

**Erick_Cantu** · 01-11-2018, 09:48

Did anyone ever figure out what units the fuel consumption tab actually uses? If you go by the docs, which say it should be expressed in g/kWh, you'll be very unpleasantly surprised if you try to plug in real numbers (as an example, the BSFC of the GEVO-12 is 0.001644 g/kWh, your tab uses a value of 198.4 units, and I'm guessing your total consumption comes out close). I ended up deriving a coefficient based on plugging in a value of 100 and seeing what result I got using the HUD. Because we can look up how much diesel fuel weighs, and we can use convert-me to easily convert units, I eliminated kg/hr as a possibility as well (it was the only other possibility I could think of, total consumption listed as some unit other than gal/hr, since BSFC varies but is usually pretty comparable across a range of power settings in real diesel engines).

My coefficient, by the way, is 3.79 (assuming fuel flow is in gallons per hour).

**R. Steele** · 01-11-2018, 11:43

Originally posted by Erick_Cantu

Did anyone ever figure out what units the fuel consumption tab actually uses? If you go by the docs, which say it should be expressed in g/kWh, you'll be very unpleasantly surprised if you try to plug in real numbers (as an example, the BSFC of the GEVO-12 is 0.001644 g/kWh, your tab uses a value of 198.4 units, and I'm guessing your total consumption comes out close). I ended up deriving a coefficient based on plugging in a value of 100 and seeing what result I got using the HUD. Because we can look up how much diesel fuel weighs, and we can use convert-me to easily convert units, I eliminated kg/hr as a possibility as well (it was the only other possibility I could think of, total consumption listed as some unit other than gal/hr, since BSFC varies but is usually pretty comparable across a range of power settings in real diesel engines).

My coefficient, by the way, is 3.79 (assuming fuel flow is in gallons per hour).

Darn good question Erick...don't know.
The reason I have ignored it...AFAIK this entry is only used for the locomotive HUD...unless the code actually uses it in an activity where you could run out of fuel and have to stop and refuel?? (does that really happen in real world...I suspect not so much, if at all)

Thanks for posting the coefficient you are using...will check it out, learning all the time.
Brilliant 3D cabs by the way...very fine work. (referring to thread over at ET)
I get ( from a converter) that 1 gal US diesel = 40.7 kwh --- does that make sense or align with what you know?

**derekmorton** · 01-11-2018, 12:40

MaximalPower ( 3281.079kW ) <<<specify kW as shown in example in manual

Need to careful here,
The manual can show THP or TKW, Traction HP or Traction KW, whereas OR needs Gross HP or KW as OR deducts Power for accessories.

**R. Steele** · 01-11-2018, 14:57

Originally posted by derekmorton

MaximalPower ( 3281.079kW ) <<<specify kW as shown in example in manual

Need to careful here,
The manual can show THP or TKW, Traction HP or Traction KW, whereas OR needs Gross HP or KW as OR deducts Power for accessories.

Derek regarding "The manual can show THP or TKW, Traction HP or Traction KW" I don't know what you are referring to.
A search in the current OR manual of either term brings up no results. Where are you getting your information??

Here's what I've been doing:
Using Convert - change HP to kW (gross - as determined by whatever web sources I can find, ops manuals, DieselShop, Wiki, and the file itself)
The gross kW entered in the ORTS block as Maximal Power
The figure entered as maximal power in watts entered in the power tab
Question: all correct so far?

When you have the time...explanation of THP or TKW vs Gross or Maximal Power, please. PM or email okay. Thank you.

**derekmorton** · 01-11-2018, 21:08

Traction horsepower = hp going to the wheels.
Gross hp = hp at the flywheel.

OR needs HP at the flywheel.

**R. Steele** · 01-12-2018, 00:32

Originally posted by derekmorton

Traction horsepower = hp going to the wheels.
Gross hp = hp at the flywheel.
OR needs HP at the flywheel.

Yes, I understand your explanation which is the general description of power loss that occurs when using a combustion motor to drive an electrical generator (either a DC generator or an AC alternator/rectifier).
There will always be more power at the "flywheel' (collectively the diesel motor) than at the driving wheel. Not being an electrical engineer my knowledge stops at the rudimentary level. Although being a former electronics tech (early days 1968 to mid 70's) I know about alternating currents, fields, early transistor theory...

The manual explicitly states "power in watts" for the diesel power tab - page 82 and Watts as the default UoM for power - page 220.
(HP is accepted, OR accepts many UoM)
I still cannot find your manual references. ...and how does all this apply to the ORTSDieselEngine block?
Why the need to be careful??? (referring the cryptic remark in post #4)

**Erick_Cantu** · 01-12-2018, 00:52

It could be a flaw in an older version of the manual that has been subsequently rectified.

**derekmorton** · 01-12-2018, 02:52

>The manual explicitly states "power in watts" for the diesel power tab

HP or watts I don't care, neither does ORTS.

You are missing the point here,
OR needs the flywheel kw as it reduces the power due to accessories.

You can check this with the aid of the HUD.

**derekmorton** · 01-12-2018, 04:08

That sounded a bit snappy. I need to tone it down a bit.

In my testing I have used kw and hp and it doesn't seem to matter.
I have just added a kw column to my spreadsheet next to the hp column so I can use either figure.
The HUD has kw on it so I will have to use kw.

The point I was trying to make was the flywheel hp, I use that term loosely, could be kw, I should have said power, while you were trying to make your point about the manual stating watts.

**tbundy1982** · 01-12-2018, 10:33

Hi Gerry, nice work on your research!

I want reiterate what I've said before about the Throttle/RPM tab. You can specify prototype RPM rates in Open Rails, but in most cases, this will cause the sounds to misbehave. Most MSTS engine sounds are based on the RPM of the engine, and MSTS did a poor job of accurately reflecting realistic RPM changes.

In MSTS, throttle power and RPM are interlinked to the throttle position, meaning that moving the throttle lever to 12.5% gives you 12.5% of the total power and 12.5% of the max RPM. Moving the throttle lever to 25% gives you 25% of the total power and 25% of max RPM, etc.

An EMD GP9 that really should remain at idle when in Run 1 is actually running at 70 RPM above idle in MSTS, and the sound of Run 1 is dependent upon the RPM being 70 RPM above idle. In Open Rails, when you make Idle and Run 1 the same RPM (difference of 1 RPM), the sounds don't understand that the throttle has moved. When you move the throttle to Run 2 with proto RPM data, the the MSTS sounds expect a 140 RPM increase from Idle, but the prototype has only increased 80 RPM.
This causes MSTS sounds to not play sequentially Idle-8 in Open Rails in the same way it would in MSTS.

Therefore, a compromise is needed. The way to work around this fault is to match the RPM increases in the ORTSDieselEngine with the "EXPECTED" RPM increases of the MSTS sound pack. A default locomotive like the GP38 has a Throttle that has an even 12.5% increase with every position, and the sound is set up to match that throttle increase. BLW locomotives that start at 5% in an attempt to provide a more prototypical power curve have a different RPM curve. In Open Rails, you would have to set the Throttle/RPM Tab up differently for these two models to achieve the best sounds.

What has worked for me is to first figure out what throttle curve the original sound set was built to, i.e. is it the default 12.5%, the BLW 5%, or something else. Once that has been determined, I subtract the minimum RPM from the maximum RPM and get a base RPM range to work with. Then, it's a process of using the percentages in the matching Throttle control section of the .eng file multiplied by the RPM base range to get each RPM increase for each throttle notch in the Throttle/RPM Tab. (For GP9: 835-275=560x0.125=70+275=345 RPM for Run 1. 560x0.25=140+275=415 RPM for Run 2, etc....)
This method preserves the function of MSTS sounds, but has a few side effects. The loco will smoke a bit going from Idle to 1 and fuel consumption rates will be slightly changed in the middle notches.

Another option is to directly edit the sound .sms files, but I don't have any knowledge of that so I compromise the RPM instead.

EDIT: You have to be careful not to mistake a revised Throttle control section for the original. Turbo Bill's ProPack 4 and 5 have brake/throttle percentages to simulate proto power curves, and I've used them to upgrade some of my locomotives. Though these are a good physics replacement, they can also mess with the sounds for the reasons described above. However, you can use these power curves in your ORTSDieselEngine section by multiplying the throttle percentages by the maximum power in watts to get the entries for the RPM/Power Tab.

Tyler

**R. Steele** · 01-12-2018, 21:40

Originally posted by derekmorton

That sounded a bit snappy. I need to tone it down a bit.

In my testing I have used kw and hp and it doesn't seem to matter.
I have just added a kw column to my spreadsheet next to the hp column so I can use either figure.
The HUD has kw on it so I will have to use kw.

The point I was trying to make was the flywheel hp, I use that term loosely, could be kw, I should have said power, while you were trying to make your point about the manual stating watts.

Derek, first off, My apologies, any "snappy tone" was a reflection of my post, which definitely started the ball rolling. I posted out of frustration trying to understand. No excuse for that. Let me carefully read the whole thread, and I'll post some coherent remarks then.
Best regards, Gerry

**R. Steele** · 01-12-2018, 21:50

Originally posted by tbundy1982

Hi Gerry, nice work on your research!

I want reiterate what I've said before about the Throttle/RPM tab. You can specify prototype RPM rates in Open Rails, but in most cases, this will cause the sounds to misbehave. Most MSTS engine sounds are based on the RPM of the engine, and MSTS did a poor job of accurately reflecting realistic RPM changes. ...Tyler

Thank you Tyler, coming from you, means a lot. I just don't have as much experience or knowledge about this as yourself, especially regarding the difference between MSTS and OR in handling the same sound files. To my tin ear, the ORTS engine block sounds just fine. Unbelievable, I know..and I do believe what you are saying...I just cannot hear it...give me 12 years of experience, like yourself, I just may begin to hear it.
Is it the OR code interpreting the sound files, or the construction of the files themselves - PLUS - how the ORTS diesel engine block is constructed...Am I even in the same neighborhood as the ballpark?

I'm going to have to read your post through several times, before I get some accurate sense of what you are saying, sorry 'bout that.

**Erick_Cantu** · 01-12-2018, 23:58

Oh, hey, Tyler, I've been meaning to PM you. I'm in the late stages of solving the 645AC/BC/C sound problem permanently (I just need to create some reworked SMS files for the AC/BC running at 800 RPM instead of the C's 835). Then there won't be need for any compromises. Want to test some aural garbage?

**tbundy1982** · 01-13-2018, 14:46

Hi guys,

Eric, I would certainly be happy to help if I can. Shoot me an email, found in one of my Readmes, or send a PM.

Gerry, sorry about the complicated post. I realize that it's a lot of information. I'd be happy to explain if you have questions.

The original problem is one caused by MSTS. RPM in MSTS is based on the Throttle percentages. Since most sounds were designed for MSTS, they are designed to interpret MSTS's non-prototype RPM modeling. When you add prototype RPM data in the ORTSDieselEngines section, sounds in the .sms get confused because they were expecting the old MSTS RPM rates instead of the new ORTS corrected RPM rates.

As I said, another option is to alter the .sms sound files, but I really don't know what I'm doing there yet. You essentially have to tell the sounds (within the .sms) to play within a certain RPM range. That allows the different throttle positions to produce different sounds. When that RPM range is changed in the .eng file, the sounds get confused because the "EXPECTED" RPM range is not there. You can get some really funky sound response with this, skipping notches or not changing sound when you move the throttle.

You have to match the RPM to the sounds or vice versa for everything to work correctly. In MSTS, this was as simple as matching the Throttle position percentages to the sound files or vice versa. With the ORTSDieselEngines data, we can dictate the RPM for each throttle position; this RPM data is what affects the sounds, not the throttle position or power output. I think the Variable2 found in the .sms files is engine RPM. Unfortunately, my knowledge and experience ends there.

Again, my RPM compromise detailed previously comes from the lack of knowledge in editing sounds. It's the cheapest fix I could think of that can be implemented with minimal side-effects.

EDIT: My example of a GP9 RPM range is different than the GEVO diesel section in the OP. Newer locomotives like the GEVO have a low idle, where an older GP9 has no low idle feature. The GEVO has 9 engine speeds and sounds, the GP9 only has 8. Idle and 1 are the same speed, and virtually the same sound, though I've been on locomotives that change sound slightly when going from Idle to 1 when the load is applied.

Tyler

Annotated ORTS Diesel Engine Block

Annotated ORTS Diesel Engine Block

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