[R H Steele]

I submitted a minor bug report for the DieselComsumptionTab found in the ORTSDieselEngines block.
The default UoM found in the manual is gal/kwh...a more user friendly approach would be the option of using gal/h and l/h - the user having to specify them.

Here's what I submitted:

Quote

As specified in the manual the default UoM for the DieselConsumptionTab, found in the ORTSDieselEngines block, is gal/kwh. That may be the technically correct term for a diesel engine running a electrical generating plant, however, it is an unfriendly term for most users.
I have tried other UoM, gal/h for instance -- the OR log shows the following warnings:
"Warning: Found a suffix 'gal/h' which could not be parsed as a Any unit in F:\2TSF\ShermanHill\trains\trainset\SLI_UNION_PACIFIC\openrails\UP_SD70ACE_8367.eng:line 25

Warning: Found a suffix 'gal/h' which could not be parsed as a Any unit in F:\2TSF\ShermanHill\trains\trainset\DWupSD70M\openrails\UP5013.eng:line 28" ***see attached log

All the engine files I've run across (NorthAmerican) list fuel consumption in gal/h, the metric equivalent being l/h.

To make OR more user friendly (specifically the ORTSDieselEngine block) the DieselConsumptionTab should accept gal/h and l/h as optional UoM.

Any conversion to gal/kwh should be done by OR, not the user.
My hope is that this presents no undue problems to change in the code.
Thank You, Gerry Storey

[ErickC]

The best part is that the units OR uses are l/h, not gal/kwh. I finally figured out where my 3.79 came from - the conversion from gallons to liters is 3.785.

[steamer_ctn]

Notes in the OR code suggest that the UoM is actually consumption vs RPM, where consumption is in litres, thus l/rpm.

    	/// Engine consumption table - Consumption vs. RPM
    	/// </summary>
    	public Interpolator DieselConsumptionTab;
    	/// <summary>

Using RPM makes sense as it allows for the engine to be running at different speeds, if an Hour UoM was used it would have to be calculated at some set speed of operation for the engine, and thus not be as accurate.

[R H Steele]

Interesting, informative regarding the reasoning used to determine correct UoM == l/rpm.
And...also an unexpected bug appears in the manual description of the UoM. Received bug report, thank you for the manual correction.

[ErickC]

In that case, it's l/h/RPM. If it were l/RPM, my GP7 figures at maximum engine speed would be off by a factor of 800...

[R H Steele]

I tried a couple of things...I changed the msts file DieselUsedPerHour lines to 0.0 - OR HUD still showed the consumption in gal/h. [My "other units" - General Tab - is set to players location]
I completely removed both DieselUsedPerHour lines from the msts file - OR HUD still showed the consumption in gal/h.
Then I removed the engine file from the OpenRails folder and changed the DieselUsedPerHour lines in the MSTS file to read 0.0 in both lines.
OR HUD then gave a reading of 0.0 US gal/h in the flow section
Conclusion: OR is reading the MSTS file for this information when the engine is not present in the OpenRails Folder.
When the engine is present in the OpenRails folder OR is getting the Diesel Consumption from the ORTS Diesel Engine file.

Now for the part I find a little confounding:
If the UoM in the Consumption tab is l/rpm then OR is converting that to whatever UoM the user has chosen. ----my choice being location (US)
If OR is capable of converting l/rpm to gal/h for the HUD, why in the devil can't it convert gal/h in the DieselConsumption tab to l/rpm for the necessary calculations?

I object.... http://www.elvastower.com/forums/public/style_emoticons/default/dry.gif this seems a little http://www.elvastower.com/forums/public/style_emoticons/default/crazy.gif .... but it's not a big deal.
No bug to report...it does appear illogical. However, I realize, in the larger scheme of issues that need to be addressed...it ranks far far down on the list.
I have searched and have yet to find a conversion (that I can understand) from gal/h to l/rpm.
I mean, was any thought ever given to how users would fill in the DieselConsumptionTab?? The default MSTS is DieselUsedPerHourAtMaxPower and in gal == gal/h

I'm left...

Attached thumbnail(s)

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[ErickC]

The units are really liters per hour at the given RPM. So the RPM is the table x-value, and the fuel flow is the y-value. All you have to do is multiply the fuel flow in gallons per hour by the conversion factor from gallons to liters - 3.785. So a hypothetical engine that consumes 5 gallons per hour at 300 RPM and 10 gallons per hour at 900 RPM would have a table that looks like this:

			DieselConsumptionTab (
				000 		00.000
				300		18.925
				900		37.850
			)

[R H Steele]

Erick, I need some clarification. Where are you getting the "per hour" part? Below is the code as posted by Peter. It makes no mention of time, just consumption vs rpm.
I admit, I hope it turns out the way you think, (man that would make it easy) but perhaps, you are assuming something not stated in the code?
In the manual under volume you will find (page 220 UoM) === Volume l diesel fuel l liter no mention of time. Note the specific mention of diesel fuel.
Unless somewhere Consumption is defined as "some unit of vol/h"?
Maybe, I'm being too literal...I hope not. Maybe peter made a typo.

steamer_ctn, on 25 January 2018 - 06:53 PM, said:

Notes in the OR code suggest that the UoM is actually consumption vs RPM, where consumption is in litres, thus l/rpm.

    	/// Engine consumption table - Consumption vs. RPM
    	/// </summary>
    	public Interpolator DieselConsumptionTab;
    	/// <summary>

Using RPM makes sense as it allows for the engine to be running at different speeds, if an Hour UoM was used it would have to be calculated at some set speed of operation for the engine, and thus not be as accurate.

[R H Steele]

Erick, I just did a test, changed tab to read

DieselConsumptionTab (
				0	0
				450  12.9l
				1050  751l
			)

No warnings. OR will accept liters as the UoM, I've been using up thread space, to chase my tail. Might as well convert the gal listed in the eng file to liters when making up the diesel engine block.
Although something feels off about the fuel flow as read in the HUD, too low perhaps.
I don't think I'll pursue this much longer, it's not that important to me now.
Although I'm glad this whole thing allowed Peter to find the typo in the manual, that's to the good.

[ErickC]

I came to my conclusion by observing how OR treats this value. I took the total fuel flow for the desired throttle settings and converted the fuel flow in gallons per hour to liters per hour, and this yielded the correct fuel flow in OR. It really is that simple. I think the OR code is merely saying that it indexes total fuel consumption (in l/h) against RPM, which is precisely what I've observed OR does. To me the phrase "Consumption vs. RPM" doesn't mean liters per revolution, rather, it means "liter per hour at specified RPM," much like the diesel power tab is engine output at the given RPM.