Eng Files for USA diesels Looking for data...
#31
Posted 21 August 2021 - 05:06 PM
Could you show a manual that gives these figures?
#32
Posted 21 August 2021 - 05:46 PM
With first generation diesels ( 567 ) using the Woodward governor, the control servo's would give the notches approximately equal spacing from 275 to 800 revs.
This arrangement would see that the power for each notch would be increased approximately by 12.5% given hardware limitations.
When we got to second generation diesels, changes could be made to the power curve and invariably did.
#33
Posted 21 August 2021 - 09:25 PM
engmod, on 21 August 2021 - 05:46 PM, said:
With first generation diesels ( 567 ) using the Woodward governor, the control servo's would give the notches approximately equal spacing from 275 to 800 revs.
This arrangement would see that the power for each notch would be increased approximately by 12.5% given hardware limitations.
When we got to second generation diesels, changes could be made to the power curve and invariably did.
So, in the case of the first generation diesels I'm using for experimentation (E8, F7 and GP9), the formula would be:
(308*(HP*(rpm/max rpm)))/mph
Is my assumption correct?
#34
Posted 21 August 2021 - 09:40 PM
Just found it, tractive effort in LB's
The 308 is not an assumption, its a well known number.
The idea of rpm/max rpm will not work, you must use 1/8 for notch 1 and 4/8 for notch 4 and so on.
#35
Posted 22 August 2021 - 12:02 AM
https://web.archive.org/web/20090415180412/http://www.alkrug.vcn.com/rrfacts/fuelSD40.htm
Am I correct that this is considered to be a US second generation diesel in this conversation? (I am guessing that 1st is 1930s-1950s with manual transitioning, 2nd is 1950s-1970s with dc generator and automatic field weakening, 3rd 1970s-2000s with alternator rather than generator and 4th 1990s-present with ac traction motors...)
7% of power is given in notch 1, rising to 36% in notch 4. It could probably be used to estimate power output at different notches for the engines on this list
https://web.archive....cts/fueluse.htm
bearing in mind that fuel use is generally most efficient at middle to high rpm.
#36
Posted 22 August 2021 - 03:44 PM
engmod, on 21 August 2021 - 09:40 PM, said:
Just found it, tractive effort in LB's
The 308 is not an assumption, its a well known number.
The idea of rpm/max rpm will not work, you must use 1/8 for notch 1 and 4/8 for notch 4 and so on.
So I was correct the first time. Thanks!
#37
Posted 22 August 2021 - 03:55 PM
#38
Posted 22 August 2021 - 04:08 PM
I have not seen these separated by the dates you suggest, but on checking, the dates ranges appear to relate to changes in traction percentage efficiency.
#39
Posted 22 August 2021 - 04:31 PM
Traindude, on 21 August 2021 - 09:25 PM, said:
(308*(HP*(rpm/max rpm)))/mph
Is my assumption correct?
There is also a formula with a number of 375 instead of the 308 value.
It all depends upon the power (hp) value used in the formula. Have a look at this post for some more detail.
Hence, if the HP value is the output power of the diesel engine then it needs to be derated to allow for losses in traction motors, generators, etc. Hence 308/375 (approx 82%) is a generic value that facilitates this derating.
However if the HP value is actually the power after these losses have been taken into account, then 375 should be used.
#40
Posted 23 August 2021 - 11:55 AM
I've always been suspicious about this...but put the problem on the back-burner...thanks to Traindude for providing a friendly push in the caboose to look for a solution.
As can be seen from the curve set, the individual curves in the set are no longer capped at a lower TE than the Maximum TE for an E8. I'm dubious about going higher than the MaxTE, even though that happens in real operations and testing...BUT...all the documentation I've seen and read states that the higher than Maximum Tractive Effort measured in a diesel-electric locomotive are momentary. Emphasis on the momentary. These higher numbers are not sustained. AFAIK.
All power settings now reach maximum TE for the E8. I'm making some other new curves up for other engines and will "foist" them upon some people for testing -- if they are amenable to the foisting.
Here's what the revised Max TE curve set will look like for the Ver3 Std_Eng files.
This is for the EMD E8: UoM are meters per sec ( m/s) & Newtons (N). Rail HP used to calculate tractive force.
This formula used to calculate curve sets: Tractive Effort vs Power - Page10
Specifications for E8:
Quote
Comment ( AAR Wheel Configuration == A1A-A1A )
Comment ( Locomotive Cyclopedia of American Practice 14thEd. 1950-52, Section 1 Pages:129-131 )
Comment ( Specifications per Operating Manual No.2311 July, 1951 3rd Edition and derived from Bob Boudoin physics )
Comment ( Frontal Area == cross sectional area == 12.93 meters squared = 139.1774ft^2 )
Comment ( Power Ratings == Gross HP 2380 == Traction HP 2250 == Rail HP 1838 )
Comment ( Continuous Tractive Effort 29203lb @ 23.3mph==81.7%eff. == Starting Tractive Effort 51856lb )
Comment ( A Unit Mass 316584lbs == 143.6t == metric )
Comment ( Weight on Drivers 211056lbs == 95.733t == metric, Adhesion Factor = 24.57% )
Comment ( Mass×Adhesion Factor = Starting Tractive Effort )
Comment ( Brake HP -- bhp = Power-at-the-shaft = Gross HP or MaximalPower )
Comment ( Gross HP per technical specs or lacking good data == add 130hp to 150hp to Traction HP )
ORTSMaxTractiveForceCurves ( 0 ( 0 0 0.74 0 1.47 0 2.21 0 2.94 0 3.68 0 4.41 0 5.14 0 5.87 0 8.69 0 12.29 0 16.76 0 21.90 0 26.82 0 32.19 0 38.00 0 44.70 0 53.64 0 ) 0.125 ( 0 230521 0.74 229183 1.47 115371 2.21 76740 2.94 57686 3.68 46086 4.41 38457 5.14 32989 5.87 28892 8.69 19506 12.29 13796 16.76 10117 21.90 7743 26.82 6323 32.19 5270 38.00 4464 44.70 3794 53.64 3162 ) 0.25 ( 0 230521 1.47 230333 2.21 153208 2.94 115167 3.68 92008 4.41 76778 5.14 65861 5.87 57682 8.69 38942 12.29 27542 16.76 20198 21.90 15458 26.82 12624 32.19 10520 38.00 8911 44.70 7575 53.64 6312 ) 0.375 ( 0 230521 2.21 229676 2.94 172648 3.68 137930 4.41 115098 5.14 98733 5.87 86471 8.69 58378 12.29 41289 16.76 30279 21.90 23173 26.82 18924 32.19 15770 38.00 13359 44.70 11355 53.64 9462 ) 0.50 ( 0 230521 2.94 230129 3.68 183853 4.41 153419 5.14 131605 5.87 115261 8.69 77813 12.29 55035 16.76 40359 21.90 30887 26.82 25225 32.19 21021 38.00 17806 44.70 15135 53.64 12613 ) 0.625 ( 0 230521 3.68 229939 4.41 191876 5.14 164594 5.87 144153 8.69 97319 12.29 68831 16.76 50476 21.90 38630 26.82 31548 32.19 26290 38.00 22269 44.70 18929 53.64 15774 ) 0.75 ( 0 230521 4.41 230197 5.14 197467 5.87 172942 8.69 116755 12.29 82577 16.76 60557 21.90 46345 26.82 37848 32.19 31540 38.00 26717 44.70 22709 53.64 18924 ) 0.875 ( 0 230521 5.14 230339 5.87 201732 8.69 136190 12.29 96324 16.76 70638 21.90 54060 26.82 44149 32.19 36791 38.00 31164 44.70 26489 53.64 22075 ) 1.0 ( 0 230521 5.87 230521 8.69 155626 12.29 110070 16.76 80718 21.90 61774 26.82 50449 32.19 42041 38.00 35611 44.70 30270 53.64 25225 ) )
Posted some relevant screenshots below. These show performance using Ver2 Max TE Curve sets.
Last Screenshot shows performance at Notch1 with new curve sets as shown above.
Lastly -- much thanks to Peter Newell for his grand Test Layout/Route...it's a gem!! (and of course for his tireless efforts in trying to improve Open Rails...and all the information on the website Coals to Newcastle