1. WLTP-21-04e Revision 1
Amendment proposals for annex 2 of GTR #15 from the cycle gearshift issues task force
Heinz Steven 1

2. Introduction
The amendment proposals are based on the analysis results of the round robin test performed by different gearshift calculation tools.
The input data of 30 different vehicles was used for this test, covering all vehicle classes and a broad variety of engine and transmission designs.
The proposals provide more specific text, where necessary, an improved rank order of the additional requirements in paragraph 4 and additional examples for more clarity.
The proposals were distributed to the GSTF and accepted by the TF. 2

3. 3.2 Determination of engine speeds
Add the following sentence at the end of this paragraph:
The calculation shall be performed with floating point numbers, the results shall not be rounded .  
Floating point number calculation was required by the TF but is not explicitly mentioned in annex 2.
This sentence is necessary in order to avoid different results, e.g. if calculations are performed with integers instead. 3

4. 3.4 Calculation of available power
When requested, the manufacturer shall provide the ASM values (in per cent reduction of the wot power) together with data sets for Pwot(n) as shown by the example  in Table A2/1. …..
“By the example” was added in order to make clear that this table shows just an example. 4

5. 3.5 Determination of possible gears to be used
The possible gears to be used shall be determined by the following conditions:
(a) The conditions of paragraph 3.3. of this annex are fulfilled, and
(b) for ngear > 2, if P available_i,j ≥ P required,j .
…..
Since it is allowed to use the 2nd gear within a short trip with slipping clutch in order to avoid a downshift to 1st gear, the power check should only be performed for ngear > 2. 5

6. Paragraph 4 (a)
The following text was moved from 4 (b) to 4 (a) in order to improve the rank order of the requirements
Gears used during accelerations at vehicle speeds ≥ 1 km/h shall be used for a period of at least 2 seconds (e.g. a gear sequence 1, 2, 3, 3, 3, 3, 3 shall be replaced by 1, 1, 2, 2, 3, 3, 3). Gears shall not be skipped during acceleration phases .
The following paragraph was inserted in order to get a more realistic gear use for capped speed cycles.
However an upshift by two gears is allowed at the transition from an acceleration phase to a constant speed phase, if the duration of the constant speed phase exceeds 5 seconds .
The requirement, that the duration of the constant speed phase shall exceed 5 seconds results from 4 (c), which covers sequences up to 5 seconds. 6

7. Paragraph 4 (b)
The following text was moved from 4 (a) to 4 (b) and further amended.
If  a one step lower gear is required at a higher vehicle speed during an acceleration phase for more than 1 second within a moving window of 10 seconds , the higher gears before shall be corrected to the lower gear. This correction shall not be performed for gear 1.
If a one step lower gear (i-1) is required at a higher vehicle speed during an acceleration phase for only 1 second within a moving window of 10 seconds and the gears before and after are the same (i) or higher, gear i-1 shall be corrected to gear i.
The moving window requirement was added in order to avoid unnecessary long periods with corrections to lower gears. 7

8. Paragraph 4 (b)
There is one example in the RRT where 6th gear is changed to 5th gear for 20 seconds although 5th gear is required for only 2 seconds within this period. The following text should be added for clarity reasons:
This check starts at the beginning of an acceleration phase. When a one step lower gear (i-1) occurs in the time series of the acceleration phase, the last second with gear i-1 before the sequence with gear i specifies the beginning of the correction period tstart and the beginning of the 10 seconds window. This window shall be applied until the end of the acceleration phase. If the one step lower gear is found for 2 or more time samples within the 10 s window, the gear correction shall be applied up to this last sample. If the lower gear is found for another time sample outside the 10 second window, the gear for this sample shall be corrected to i. 8

9. Paragraph 4 (b) Examples
If the initially calculated gear use is 2,2,3,[3,4,4,[4,4,3,4,4,4,4],4,4,3],4,4,4, the gear use shall be corrected to
2,2,3,3,3,3,3,3,3,3,3,3,3,3,3,3,4,4,4.
If the initially calculated gear use is 2,2,3,[3,4,4,3,4,[4,4,4,4,4],4,4,4,4,3],4, the gear use shall be corrected to
2,2,3,3,3,3,3,4,4,4,4,4,4,4,4,4,4,4,4.
The same approach shall be used for a two step lower gear. 9

10. Paragraph 4 (c) The text in 4 (c) should be modified as follows:
If gear i is used for a time sequence of 1 to 5 seconds and the gear prior to this sequence is one step lower and the gear after this sequence is one or two steps lower than within this sequence or the gear prior to this sequence is two steps lower and the gear after this sequence is one step lower than within the sequence, the gear for the sequence shall be corrected to the maximum of the gears before and after the sequence .
Justification: If you replace 3,4,4,4,2 by 3,3,3,3,2, what is covered by the previous text under 4 (c), it should also be allowed to change 2,4,4,4,3 to 2,3,3,3,3. This is the aim of the text amendment. The examples were supplemented accordingly. 10

11. Paragraph 4 (c)
This amendment is also proposed for the first part of paragraph 4 (a), which is the same as paragraph 4 (c) (i), whose text is as follows:
(i) gear sequence i−1, i, i−1 shall be replaced by:
i−1, i−1,i−1;
gear sequence i-1, i, i-2 shall be replaced by
i-1, i-1, i-2;
gear sequence i-2, i, i-1shall be replaced by
i-2, i-1, i-1. 11

12. Paragraph 4, rank order
It is proposed to move the requirement 4 (g) (No  upshift to a higher gear at the transition from an acceleration or constant speed phase to a deceleration phase) to 4 (d) in order to improve the results and to add the following sentence for clarity reason:
No upshift to a higher gear shall be performed within a deceleration phase.
The following paragraphs were renumbered accordingly.   12

13. Paragraph 4 (e) new
It is proposed to restructure the rank order of the requirements for deceleration phases (4 (d), 4 (e) and 4 (f)) in the previous annex 2 text) in order to improve the results.
4 (e) new contains now the general requirements about the gear use during deceleration phases and reads as follows:
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. 13

14. Paragraph 4 (e) new
The following text should be added for clarity reasons:
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 . 14

15. Paragraph 4 (f) new
4 (f) new contains the requirements that are needed to avoid gear sequences of less than 3 s and to avoid too long sequences with gear 0.
The requirements in the previous version of annex 2 could lead to sequences of up to 4 seconds with gear 0.
If  during a deceleration phase the duration of a gear sequence between two gear sequences of 3 seconds or longer is only 1 second, it shall be replaced by gear 0 and the clutch shall be disengaged.
If during a deceleration phase the duration of a gear sequence between two gear sequences of 3 seconds or longer is 2 seconds, it shall be replaced by gear 0 for the 1st second and for the 2nd second with the gear that follows after the 2 second period. The clutch shall be disengaged for the 1st second. 15

16. Paragraph 4 (f) new It is proposed to add the following text:
If several gear sequences with durations of 1 or 2 seconds follow one after another, corrections shall be performed as follows:
A.gear sequence i, i, i, i-1, i-1, i-2 or i, i, i, i-1, i-2, i-2 shall be changed to i, i, i, 0, i-2, i-2. A.gear sequence like i, i, i, i-1, i-2, i-3 or i, i, i, i-2, i-2, i-3 or other possible combinations shall be changed to i, i, i, 0, i-3, i-3.
The requirements above are related to a deceleration window of 6 seconds. The WLTC contains some decel phases that are shorter. In order to cover them properly, the following paragraph should be added.
This change shall also be applied on gear sequences where the acceleration is ≥ 0 for the first 2 seconds and < 0 for the 3rd second or where the acceleration is ≥ 0 for the last 2 seconds . 16

17. Paragraph 4 (f) new
For extreme transmission design it could happen, that the several gear sequences with durations of 1 or 2 seconds following one after another last up to 7 seconds. In such cases the correction above needs to be complemented by the following correction requirements in a second step:
A gear sequence j, 0, i, i, i-1, k with j > i+1 and k ≤ i-1 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).
If gear i-1 is more than two steps below imax for second 3 of this sequence, a gear sequence j, 0, i, i, i-1, k with j > i+1 and k ≤ i-1 shall be changed to j, 0, 0, k, k, k.
A gear sequence j, 0, i, i, i-2, k with j > i+1 and k ≤ i-2 shall be changed to j, 0, i-2, i-2, i-2, k, if gear i-2 is one or two steps below imax for second 3 of this sequence (one after gear 0). 17

18. Paragraph 4 (f) new
If gear i-2 is more than two steps below imax for second 3 of this sequence, a gear sequence j, 0, i, i, i-2, k with j > i+1 and k ≤ i-2 shall be changed to j, 0, 0, k, k, k.
The requirement above is proposed for completeness reasons. Even for the most extreme vehicle in the RRT test with a 10speed gearbox it was not necessary.
If  the deceleration phase is the last part of a short trip shortly before a stop phase and the last gear > 0 before the stop phase is only used for a period of up to two seconds, gear 0 shall be used instead and the gear lever shall be placed in neutral and the clutch shall be engaged.
In the previous version the text was related to 2nd gear only, but the examples were related to the text proposed above (last gear > 0). 18

19. Thank you for your attention!
End
Thank you for your attention! 19