1. WLTP-26-03e - Revision 1
Final amendments for annex 2 and status report about the programming code development subgroup
Heinz Steven 1

2. Work done so far The task force had a web-telco at 27.02.2019
The TF leader gave an overview about the discussions at the last WLTP IWG meeting (#25 7th of January in Geneva) with regard to the request of a TF member to add a programming code to annex 2 as an appendix.
This request was accepted by the IWG and the TF leader got the task to re-establish the GSTF in order to develop an Appendix for Annex 2 of GTR 15 that contains the programming code for the annex 2 requirements.
He asks the TF to appoint members for this subgroup till mid of March. This has been done and the following persons were appointed: 2

3. Work done so far The subgroup will start its work right after IWG #26.3

4. Work done so far
At the web-telco the TF leader expressed his view that there is a need to further improve the text in annex 2. He presented WLTP-GS-TF-38 which contained already some examples for such improvements.
From discussions with some OEMs could be concluded that there is also a need to improve the text in annex 1 in order to clarify the durations of the cycle phases.
A proposal was added to the agenda of the web-telco as revision 1.
After the web-telco the TF leader did some analysis work related to the structure of annex 2 of GTR 15 and to further amendment proposals. 4

5. Work done so far
The outcome of this work is presented in revision 2 of WLTP-GS-TF-38 which was distributed to the TF members mid of March 2019.
An improved ACCESS tool considering the proposed amendments was also circulated.
The TF leader did calculations with this new tool and the latest version from the UN-WLTP website (version from ) for 115 different vehicle configurations.
For 72 configurations no differences between version (amendment 5) and version (draft for amendment 6) were found. 5

6. Work done so far
The differences for the other 43 configurations are shown in an Excel table which was also sent to the TF members and which is embedded in this slide.
It can be concluded that the new amendment proposals lead to improved gear use patterns and reduce the number of gearshifts.
The TF leader asked the TF members to examine his proposals and give him feedback till end of March.
He expressed his whish to get the amendments approved by the TF early enough prior to the next IWG meeting in Zagreb, so that they could be discussed in the IWG during this meeting and so that the work on the programming codes could be started. 6

7. Amendment proposals for annex 1
Since there was no negative feedback from the TF members the following amendments are proposed to be discussed by the IWG at its meeting in Zagreb with the request for adoption:
Replace the current paragraph 3.4 by the following, more precise text:
3.4. Duration of all phases
All low speed phases last 589 seconds.
All medium speed phases last 433 seconds.
All high speed phases last 455 seconds.
All extra high speed phases last 323 seconds.
3.4. Duration of the cycle phases 
Class 1 cycle.
The first low speed phase starts at second 0 and ends at second 589 (duration 589 s)
The medium speed phase starts at second 589 and ends at second 1022 (duration 433 s)
The second low speed phase starts at second 1022 and ends at second 1611 (duration 589 s) 7

8. Amendment proposals for annex 1
Class 2 and class 3 cycles.
The low speed phase starts at second 0 and ends at second 589 (duration 589 s)
The medium speed phase starts at second 589 and ends at second 1022 (duration 433 s)
The high speed phase starts at second 1022 and ends at second 1477 (duration 455 s)
The extra high speed phase starts at second 1477 and ends at second 1800 (duration 323 s)
This amendment is proposed in order to make the text robust against misinterpretation. 8

9. Amendment proposals for annex 1
Within this context it is also proposed to add expanatory text to the headers of tables A1/1 to A1/12 in order to make the annex robust against misinterpretation and add a new table A1/3 containing the time series of the vehicle speed for the second Low phase of the class 1 cycle in order to clearly demonstrate that the class 1 cycle consists of three phases.
An example for explanatory text is shown in the following:
Table A1/1
WLTC, Class 1 cycle, phase Low11 (Second 589 is the end of phase Low11 and the start of phase Medium1)
The numbering of all tables of annex 1 following the new table A1/3 must be amended accordingly. 9

10. Amendment proposals for annex 1
A 3rd amendment for annex 1 is proposed for the equations in paragraphs , and with the same justification as for the previous amendments.
The equation in paragraph reads:
dmedium = ∑(((vi+vi-1 ))/(2×3.6)×(ti- ti-1 )), for i = 591 to 1022
for i = 591 to 1022 should be replaced by for i = 590 to 1022, in order to include also the start second of the phase.
In paragraph for i = 1024 to 1477 should be replaced by for i = 1023 to 1477; and in paragraph for i = 1479 to 1800 should be replaced by for i = 1478 to 1800.
This amendment is proposed for consistency reasons. 10

11. Amendment proposals for annex 2
Paragraph 2 (j) (4), correct wrong reference in the specifications for vmax:
The current text is:
vmax is the maximum vehicle speed as specified in paragraph 2. (i) of this annex. Only the vmax value resulting from the intersection of the required road load power curve and the available power curve of the relevant gear shall be used for the conditions in (3) and (4) above. A vmax value resulting from a limitation of the engine speed which prevents this intersection of curves shall not be used;
It should read:
vmax is the maximum vehicle speed as specified in paragraph 2. (i) of this annex. Only the vmax value resulting from the intersection of the required road load power curve and the available power curve of the relevant gear shall be used for the conditions in (2) and (3) above. A vmax value resulting from a limitation of the engine speed which prevents this intersection of curves shall not be used; 11

12. Amendment proposals for annex 2
Paragraph 3.3, add the requirements from paragraph 4(e) at the end of this paragraph for the sake of logic:
With regard to the definition of nmin_drive in paragraph 2 (k) the requirements (a) to (c) specified above can be expressed as follows for deceleration phases:
During  a deceleration phase, gears with ngear > 2 shall be used as long as the engine speed does not drop below nmin_drive.
Gear 2 shall be used during a deceleration phase within a short trip of the cycle (not at the end of a short trip) as long as the engine speed does not drop below (0.9 × nidle).
If the engine speed drops below nidle, the clutch shall be disengaged.
If the deceleration phase is the last part of a short trip shortly before a stop phase, the second gear shall be used as long as the engine speed does not drop below nidle.
 Justification: This text is the former text of paragraph 4(e) but its context is clearly related to this paragraph, because it specifies the selection of gears during deceleration phases. 12

13. Amendment proposals for annex 2
Paragraph 4, add the text highlighted in yellow to the 2nd sub-paragraph:
An acceleration phase is a time period of more than 2 seconds with a vehicle speed ≥ 1 km/h and with strictly monotonic increase of vehicle speed. A deceleration phase is a time period of more than 2 seconds with a vehicle speed ≥ 1 km/h and with strictly monotonic decrease of vehicle speed. A constant speed phase is a time period of more than 2 seconds with a constant vehicle speed ≥ 1 km/h. Acceleration, deceleration or constant speed sections include also time periods of 2 seconds .  
Justification: This text is inserted for completeness and precision reasons. 13

14. Amendment proposals for annex 2
Paragraph 4, insert the following text at the beginning of this paragraph:
The modification check described in paragraph 4.(a) of this annex shall be applied to the complete cycle trace twice prior to the application of the following paragraphs of this annex .  
Justification: This amendment is necessary in order to avoid a too early application of 4(d) and 4(f), that would cause wrong gear modifications. 14

15. Amendment proposals for annex 2
Paragraph 4 (a), replace the current text in the 2nd sub-paragraph by the following more precise text:
Gears used during accelerations or constant speed sections at vehicle speeds ≥ 1 km/h shall be used for a period of at least 2 seconds .
If, during acceleration or constant speed sections or transitions from constant speed to acceleration or acceleration to constant speed sections where these sections only contain upshifts, a gear is used for only one second, the gear in the following second shall be corrected to the gear before, so that a gear is used for at least 2 seconds.
Justification: The text as it was is not precise enough and needs to be improved in order to prohibit backwards corrections. 15

16. Amendment proposals for annex 2
Paragraph 4 (a), modify the current text in the 3rd sub-paragraph as follows:
This requirement shall not be applied to downshifts during an acceleration phase or if the use of a gear for just one second follows immediately after such a downshift or if the downshift occurs right at the beginning of an acceleration phase. In these cases, the downshifts shall be first corrected according to paragraph 4.(b) of this annex.
Justification: This amendment proposal is based on a reasonable request from Indian colleagues. Paragraph 4(b) corrects downshifts during acceleration phases but excludes the beginning of such phases up to now.
The following example was modified accordingly. 16

17. Amendment proposals for annex 2
Paragraph 4 (a), add a 4th sub-paragraph as follows:
However, if the gear at the beginning of an acceleration phase is one step lower than the gear in the previous second and the gears in the following (up to five) seconds are the same as the gear in the previous second but followed by a downshift, so that the application of 4.(c) would correct them to the same gear as at the beginning of the acceleration phase, the application of 4.(c) should be performed instead .  
Justification: To avoid too many gearshifts.
An exemplary example was added in WLTP-GS-TF-39. 17

18. Amendment proposals for annex 2
Paragraph 4 (a), add a 5th sub-paragraph as follows:
Furthermore, if the gear in the first second of an acceleration phase is the same as the gear in the previous second and the gear in the following seconds is one step higher, the gear in the second second of the acceleration phase shall be replaced by the gear used in the first second of the acceleration phase.  
Justification: Ensure the use of a gear for at least 2 seconds during an acceleration phase.
An exemplary example was added in WLTP-GS-TF-39. 18

19. Amendment proposals for annex 2
Paragraph 4 (a), modify the 6th sub-paragraph as follows (highlighted in yellow):
Gears shall not be skipped during upshifts within  acceleration phases.
Justification: “upshifts within” was added for clarity reasons.
Paragraph 4(b), modify the 1st sentence as follows:
If a downshift is required during an acceleration phase or at the beginning of the acceleration phase, the gear required during this downshift shall be noted (iDS).  
Justification: See proposed modifications in the 3rd sub-paragraph of 4(a). 19

20. Amendment proposals for annex 2
Paragraph 4 (b), delete the last sub-paragraph and insert it in paragraph 5 as 5(b).
Paragraph 4(d), change the rank order of the requirements:
The check for downshifts during deceleration phases should be performed prior to the check for downshifts at the transitions from an acceleration or constant speed phase to a deceleration phase.
Justification: Leads to more reasonable results.
Paragraph 4(e) can be deleted because it was integrated in paragraph 3.3 20

21. Amendment proposals for annex 2
Paragraph 4 (f), change the rank order of the requirements:
The last 3 sub-paragraphs should be moved to the beginning of this paragraph.
Justification: The application of these requirements prior to the other requirements improves the results.
Paragraph 4(f) contains 4 sub-paragraphs with gear sequences using i, j and k as gear values, e.g.:
A gear sequence j, 0, i, i, i - 1, k with j > (i + 1) and k ≤ (i – 1) but k > 0  shall be changed to j, 0, i - 1, i - 1, i - 1, k, if gear (i – 1) is one or two steps below imax for second 3 of this sequence (one after gear 0).  “but k > 0” was added for clarity reasons.
“but k > 0” was added for clarity reasons. 21

22. Amendment proposals for annex 2
Paragraph 5, a new structure and the supplement of the last sub-paragraph in 4(b) is proposed
The first sub-paragraph becomes 5(a), the last sub-paragraph from 4(b) should be inserted as 5(b), the last sub-paragraph becomes 5(c).
The first sub-paragraph should be amended as follows:
Paragraphs 4.(a) to 4.(f) inclusive of this annex shall be applied sequentially, scanning the complete cycle trace in each case. Since modifications to paragraphs 4.(a) to 4.(f) inclusive of this annex may create new gear use sequences, these new gear sequences shall be checked three times twice and  modified if necessary.  
Justification: With the other modifications twice is sufficient. This was checked for 115 different vehicle configurations. 22

23. Amendment proposals for annex 2
Paragraph 5(b) which was moved from the end of 4(b) reads:
After the application of paragraph 4.(b) of this annex, a downshift by more than one gear could occur at the transition from a deceleration or constant speed phase to an acceleration phase.
In this case, the gear for the last sample of the deceleration or constant speed phase shall be replaced by gear 0 and the clutch shall be disengaged. If the “suppress gear 0 during downshifts” option according to paragraph 4.(f) of this annex is chosen, the gear of the following second (first second of the acceleration phase) shall be used instead of gear 0.
Justification: This correction should be applied after all calculation laps are performed. This will improve the results of the GS calculation. 23

24. Final remarks
The amendment proposals in this report are also integrated in annex 1 and annex 2 of GTR 15 amendment 5, which is attached as WLTP-GS-TF-39. 24

25. Thank you for your attention!
End
Thank you for your attention! 25