[Jean-Paul]

darwins, on 27 July 2019 - 01:41 AM, said:

Some further observations.
Having just realised that another power car with MSTS eng file was pushing mine http://www.elvastower.com/forums/public/style_emoticons/default/sign_sorry.gif So now just experimenting with a single power car.
( 1 ) Using ORTS diesel engines only diesel mechanical transmission does not work. The engines rev up and make lots of smoke but there is no power output. The engines rev up and make lots of smoke but the gears remain firmly in neutral and there is no power output at the wheels.
( 2 ) If you add only the following lines of MSTS code (outside of the ORTS diesel engine definition) then the manual gears will work:

DieselEngineIdleRPM( 400 )
DieselEngineMaxRPM( 1800 )
regardless of those factors being defined within the OR diesel engine section or not.
However the power output from the engines fluctuates wildly in a sawtooth fashion in first gear.

https://i.imgur.com/iqt5OPl.jpg

There is some fluctuation in higher gears but it is fairly minimal and not like the wild situation in first gear.
( 3 ) On the other hand if there is only an MSTS definition for the diesel engine an no ORTS diesel engines are defined then power output looks reasonable
https://i.imgur.com/J9Leaeh.png
Not sure if this helps solving the problem, but it may mean that for the moment it is best to remain with the MSTS diesel engine definitions when dealing with mechanical transmissions.

Hello !
I tried last week with a very classical .eng (MSTS type), and it works perfectly under Openrails. I send it, so, you can try it. The only "problem" is you can't combine OR PowerCurves with a mechanical transmission. Is that really a problem ? I'm not sure, because Openrails introduces some artefacts like clutch gliding, which allows better results at starting that the old MSTS. I must admit that it should be perfect if we could have more realistic power curves, taking in account torque values following RPM variations, but it works like this.
Best Regards,
Jean-Paul  BRCW_104_DMBSwg.eng (37.97K)
Number of downloads: 447

[darwins]

Jean-Paul, on 27 July 2019 - 12:33 PM, said:

Hello !
I tried last week with a very classical .eng (MSTS type), and it works perfectly under Openrails. I send it, so, you can try it. The only "problem" is you can't combine OR PowerCurves with a mechanical transmission. Is that really a problem ? I'm not sure, because Openrails introduces some artefacts like clutch gliding, which allows better results at starting that the old MSTS. I must admit that it should be perfect if we could have more realistic power curves, taking in account torque values following RPM variations, but it works like this.
Best Regards,
Jean-Paul BRCW_104_DMBSwg.eng

Many thanks for that. I think my answer will be to use a mixture of MSTS and OR engine definitions.

The ORTS engines are good for changing the colour of the smoke! Those trains always used to depart in clouds of light grey fumes!
The disappointment in not being able to use ORTS engines is that the MSTS definition does not allow different speeds for increase and decrease in rpm.
Not a problem really as the engine is mostly under load.
So I will opt for something like DieselEngineMaxRPMChangeRate ( 240 ) rather than DieselEngineMaxRPMChangeRate ( 80 ) so that engine speed can drop quickly enough for gear changes.
This seems to give me something like: Comment (************************ Diesel Engine ****************)

MaxDieselLevel( 180g-uk )

MaxVelocity ( 70mph )
DieselEngineIdleRPM( 400 )
DieselEngineMaxRPM( 1800 )
DieselEngineMaxRPMChangeRate( 240 )

ORTSDieselEngines ( 2
Diesel(
MaximalPower ( 150hp )
IdleExhaust ( 6 )
MaxExhaust ( 30 )
ExhaustDynamics ( 5 )
ExhaustDynamicsDown ( 0.5 )
ExhaustColor ( 405F6E73 )
ExhaustTransientColor ( 7F6B787D )

DieselConsumptionTab (
0 0
400 3
1200 16
1400 21
1600 26
1800 32
)

MinOilPressure ( 40 )
MaxOilPressure ( 90 )
MaxTemperature ( 120 )
Cooling ( 3 )
TempTimeConstant ( 720 )
OptTemperature ( 90 )
IdleTemperature ( 70 )
)
Diesel(

http://www.elvastower.com/forums/public/style_emoticons/default/sign_thank_you.gif

[R H Steele]

darwins and I have been carrying on this thread in a PM and he asked if I would post part of our conversation in this thread...so here goes. By the way, since I offerred this advice, he has made some improvements to the diesel engine files I provided...others with interest in diesel power transmissions other than diesel electric ---this is an interesting thread.

Quote

attached is a new eng file with two ORTS Diesel Eng Blocks.When I tested the eng file provided the first thing I did was to review the OR log for warnings or errors. If OR finds something improper with the ORTS Eng block it will default to any MSTS data. If the MSTS data is incorrect or incomplete OR may generate strange readings in the Loco Hud...something you experienced...saw toothing...I've had that happen also during testing.
Here's the warnings I observed in my log:

Quote

Warning: Diesel engine model has some errors - loading MSTS format in F:\2TSF\CTN_TEST_ROUTE\trains\trainset\NS_BRCW 104 LMR Whiskers\BRCW_104_DMBSwg.eng:line 644

Warning: Diesel engine model has some errors - loading MSTS format in F:\2TSF\CTN_TEST_ROUTE\trains\trainset\NS_BRCW 104 LMR Whiskers\BRCW_104_DMBSwg.eng:line 671

The attached eng file does not provoke any warnings in the log. I used all the data you provided to construct the eng blocks, without accurate data I just made my best guess-estimates. You'll want to review the file and make changes, especially to the RPM rate of change lines, DieselPowerTab, ThrottleRpmTab, and the exhaust lines.
Here's some things I've found testing all my OR Standard eng files:
1. UoM other than the defaults listed in the manual (sec 22.1 ) must be expressed, eg. 150HP ( default is watts ) --- no space between the value and UoM.
2. The ORTSDieselEng block must be included in its entire form....the only optional line or Tab is the "ExhaustDynamicsDown" line.

Sec 8.2.1

Quote

If the ORTS specific definition is used, each parameter is tracked and if one is missing (except in the case
of those marked with Optional), the simulation falls back to use MSTS parameters.

3. If two OR diesel eng blocks are used ( as is the case here ) -- the two blocks may differ, they do not have to be identical.
4. I'm not sure about this, but I believe it to be so...need to do some more testing >> the DieselPowerTab and ThrottleRpmTab should both have nine lines...this puzzles me because both are really only listing intermediate values from zero to one -- the OR interpolator will calculate values not listed.
5. A common error I've made is not having increasing values in the various tabs within the OR diesel eng block...this will provoke a warning in the log.
Hope all this helps, good luck --- I hope your work will help make some improvements to the code.

here's the ORTS diesel engine file I made up for darwins:

ORTSDieselEngines ( 2
	Diesel(		
	IdleRPM	( 400 )
	MaxRPM	( 1800 )
	StartingRPM	( 200 )
	StartingConfirmRPM	( 300 )
	ChangeUpRPMpS	( 240 )
	ChangeDownRPMpS	( 151 )
	RateOfChangeUpRPMpSS	( 89 )
	RateOfChangeDownRPMpSS	( 60 )
	MaximalPower  ( 111855 )
	IdleExhaust	( 1.2 )
	MaxExhaust	( 2.2 )
	ExhaustDynamics	( 1.6 )
	ExhaustDynamicsDown	( 0.8 )
	ExhaustColor	( 405F6E73 )
	ExhaustTransientColor	( 7F6B787D )
	DieselPowerTab (		
		0	0
		580	13982
		760	27964
		940	41946
		1120 55927
		1300 69909
		1480 83891
		1660 97873
		1800 111855
	)
	DieselConsumptionTab (		
		0	0
		400	3
		1200	16
		1400	21
		1600	26
		1800	32
	)
	ThrottleRPMTab (		
		0	400
		12.5	580
		25	760
		37.5	940
		50	1120
		62.5	1300
		75	1480
		87.5	1660
		100	1800
	)		
	DieselTorqueTab (		
		0	0
		400	1969.5
		1800 437.7
	)		
	MinOilPressure	( 40 )
	MaxOilPressure	( 90 )
	MaxTemperature	( 120 )
	Cooling	( 3 )
	TempTimeConstant	( 720 )	
	OptTemperature	( 90 )
	IdleTemperature	( 70 )
	)		
Diesel(		
	IdleRPM	( 400 )
	MaxRPM	( 1800 )
	StartingRPM	( 200 )
	StartingConfirmRPM	( 300 )
	ChangeUpRPMpS	( 240 )
	ChangeDownRPMpS	( 151 )
	RateOfChangeUpRPMpSS	( 89 )
	RateOfChangeDownRPMpSS	( 60 )
	MaximalPower  ( 111855 )
	IdleExhaust	( 1.2 )
	MaxExhaust	( 2.2 )
	ExhaustDynamics	( 1.6 )
	ExhaustDynamicsDown	( 0.8 )
	ExhaustColor	( 405F6E73 )
	ExhaustTransientColor	( 7F6B787D )
	DieselPowerTab (		
		0	0
		580	13982
		760	27964
		940	41946
		1120 55927
		1300 69909
		1480 83891
		1660 97873
		1800 111855
	)
	DieselConsumptionTab (		
		0	0
		400	3
		1200	16
		1400	21
		1600	26
		1800	32
	)
	ThrottleRPMTab (		
		0	400
		12.5	580
		25	760
		37.5	940
		50	1120
		62.5	1300
		75	1480
		87.5	1660
		100	1800
	)		
	DieselTorqueTab (		
		0	0
		400	1969.5
		1800 437.7
	)		
	MinOilPressure	( 40 )
	MaxOilPressure	( 90 )
	MaxTemperature	( 120 )	
	Cooling	( 3 )
	TempTimeConstant	( 720 )
	OptTemperature	( 90 )
	IdleTemperature	( 70 )
	)
)

[darwins]

I was very pleased to get a working eng file that did not need any MSTS bits and no saw tooth problem in the power development.

However I did find the train underperforming in terms of hp at the rails, although I was fairly sure that the resistance set was reasonable.

Going back to the data available (BUT 150 hp engine) I edited the power tab and then calculated a torque table. I am not sure why OR needs a torque table when this can be calculated from W and rpm.

Torque (N.m) = power (W) * 9.5488 / rpm.

DieselPowerTab (
0 0
400 19388
1200 79789
1400 96195
1480 102160
1520 104398
1600 106635
1800 111855
2000 92466
)

DieselTorqueTab (
0 0
400 462
1200 634
1400 656
1480 659
1520 655
1600 636
1800 593
2000 441
)


This gave rather more than excellent performance as there did not seem to be any transmission losses. So I ended up reducing the numbers a little.

The 2000 rpm line was added as a guess as to how power will drop off when the engine is 'overspeed', since the gearbox is set to max rpm at 65.5 mph, but the trains could and did run at 70!

Without that OR continued to increase power and torque above the set maximum engine speed, adding a line for 2000 rpm checks that tendency.

However there was still a problem of a strange drop in rpm and rise again, like an automatic gear change, this was especially noticable in first gear.

Reducing ChangeUpRPMpS moves this behaviour to a lower engine speed and makes it less noticeable. However too bigger reduction will slow acceleration of the train.

I found that setting this to 90 gives the appropriate acceleration, but still leaves the drop far enough down to be insignificant.

Also along the way I found out that I can put less than 9 values in the throttle tab without getting an error warning.

So my final 150 hp diesel engine looks like this:

Diesel(
IdleRPM ( 400 )
MaxRPM ( 1800 )
StartingRPM ( 200 )
StartingConfirmRPM ( 300 )
ChangeUpRPMpS ( 90 )
ChangeDownRPMpS ( 240 )
RateOfChangeUpRPMpSS ( 60 )
RateOfChangeDownRPMpSS ( 60 )
MaximalPower ( 111855 )
IdleExhaust ( 1.2 )
MaxExhaust ( 2.2 )
ExhaustDynamics ( 1.6 )
ExhaustDynamicsDown ( 0.8 )
ExhaustColor ( 405F6E73 )
ExhaustTransientColor ( 7F6B787D )
DieselPowerTab (
0 0
400 17896
1200 76061
1400 91721
1480 97686
1520 99923
1600 102160
1800 107380
2000 88738
)
DieselConsumptionTab (
0 0
400 6
600 10
1100 18
1400 24
1800 34
)
ThrottleRPMTab (
0 400
15 600
50 1100
70 1400
100 1800
)
DieselTorqueTab (
0 0
400 427
1200 605
1400 625
1480 630
1520 627
1600 609
1800 569
2000 423
)
MinOilPressure ( 40 )
MaxOilPressure ( 90 )
MaxTemperature ( 120 )
Cooling ( 3 )
TempTimeConstant ( 720 )
OptTemperature ( 90 )
IdleTemperature ( 70 )
)

At the end of which I thought I would try out a variation. Make the slightly more powerful 180 hp version of the above engine. So I took the power tab and multiplied the power values by 6/5 and made a new torque tab to go with it.

When I tried this one out the saw teeth were back again! After experimenting with various factors I found that they were removed by increasing the value of RateOfChangeUpRPMpSS ( 60 ).

So for the larger engine I have:

Diesel(
IdleRPM ( 400 )
MaxRPM ( 1800 )
StartingRPM ( 200 )
StartingConfirmRPM ( 300 )
ChangeUpRPMpS ( 100 )
ChangeDownRPMpS ( 240 )
RateOfChangeUpRPMpSS ( 120 )
RateOfChangeDownRPMpSS ( 60 )
MaximalPower ( 134226 )
IdleExhaust ( 1.2 )
MaxExhaust ( 2.2 )
ExhaustDynamics ( 1.6 )
ExhaustDynamicsDown ( 0.8 )
ExhaustColor ( 405F6E73 )
ExhaustTransientColor ( 7F6B787D )
DieselPowerTab (
0 0
400 20879
1200 90975
1400 109617
1480 117074
1520 119312
1600 122294
1800 128260
2000 97612
)
DieselConsumptionTab (
0 0
400 7
600 12
1100 22
1400 29
1800 41
)
ThrottleRPMTab (
0 400
15 600
50 1100
70 1400
100 1800
)
DieselTorqueTab (
0 0
400 498
1200 723
1400 747
1480 755
1520 749
1600 729
1800 680
2000 466
)
MinOilPressure ( 40 )
MaxOilPressure ( 90 )
MaxTemperature ( 120 )
Cooling ( 3 )
TempTimeConstant ( 720 )
OptTemperature ( 90 )
IdleTemperature ( 70 )
)

Hopefully now I can carry on to the 238 hp variants!!!

No idea why some of these things work the way they do, but hope this will be useful to others. A final eng file is attached.

Attached File(s)

•  BRCW_104_DMBSwg.eng (41.3K)
  Number of downloads: 328

[darwins]

Oh the saw teeth do plague me again...http://www.elvastower.com/forums/public/style_emoticons/default/sweatingbullets.gif
What works for one engine may be does not work for another.

Strange thing this time... if I put just the one engine it is fine, but with two identical engines it is not.
By making some of the figures a little different for each engine I am managing to smooth them out a bit. Two different engines can even combine together to give me fairly continuous negative horse power....
But then that is what the saw teeth are - the horse power goes low or even negative whilst rpm continues to rise.