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APPENDIX 1
SAMPLE POINT CONNECTION FLANGE
1 The following is an example of a general purpose sample point connection flange which should be sited, as convenient, on the exhaust duct of each engine for which it may be required to demonstrate compliance by means of the direct measurement and monitoring method.
| Description |
Dimension |
| Outer diameter |
160 mm |
| Inner diameter |
35 mm |
| Flange thickness |
9 mm |
| Bolt circle diameter 1 |
130 mm |
| Bolt circle diameter 2 |
65 mm |
| Flange slots |
4 holes, each 12 mm diameter, equidistantly placed on each of the above bolt circle diameters. Holes on the two bolt circle diameters to be aligned on same radii. Flange to be slotted, 12 mm wide, between inner and outer bolt circle diameter holes. |
| Bolts and nuts |
4 sets, diameter and length as required |
| Flange should be of steel and be finished with a flat face. |
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2 The flange should be fitted to a stub pipe of suitable gauge material aligned with the exhaust duct diameter. The stub pipe should be no longer than necessary to project beyond the exhaust duct cladding, sufficient to enable access to the far side of the flange. The stub pipe should be insulated. The stub pipe should terminate at an accessible position free from nearby obstructions which would interfere with the location or mounting of a sample probe and associated fittings.
3 When not in use, the stub pipe should be closed with a steel blank flange and a gasket of suitable heat resisting material. The sampling flange, and closing blank flange, when not in use, should be covered with a readily removable and suitable heat resistant material which protects against accidental contact.
APPENDIX 2
SELECTION OF LOAD POINTS AND REVISED WEIGHTING FACTORS
1 As provided for by Section 3.1 of these Guidelines, in the case of the E2/E3/D2 test cycles, the minimum number of load points should be such that the combined nominal weighting factors as given in the NOx Technical Code, paragraph 3.2, are greater than 0.50.
2 Consequently, for the E2/E3 test cycle it would be necessary to use the 75% load point plus one or more other load points. In the case of the D2 test cycle, either the 25% or 50% load point should be used plus either one or more load points such that the combined nominal weighting factor is greater than 0.50.
3 The examples below give some of the possible combinations of load points which may be used together with the respective revised weighting factors:
E2/E3 test cycles
| Power |
100% |
75% |
50% |
25% |
| Nominal weighting factor |
0.2 |
0.5 |
0.15 |
0.15 |
| Option A |
0.29 |
0.71 |
|
|
| Option B |
|
0.77 |
0.23 |
|
| Option C |
0.24 |
0.59 |
|
0.18 |
| Plus other combinations which result in a combined nominal weighting factor greater than 0.50. Hence use of the 100% + 50% + 25% load points would be insufficient. |
|
D2 test cycle
| Power |
100% |
75% |
50% |
25% |
10% |
| Nominal weighting factor |
0.05 |
0.25 |
0.3 |
0.3 |
0.1 |
| Option D |
|
|
0.5 |
0.5 |
|
| Option E |
|
0.45 |
|
0.55 |
|
| Option F |
|
0.38 |
0.46 |
|
0.15 |
| Option G |
0.06 |
0.28 |
0.33 |
0.33 |
|
| Plus other combinations which result in a combined nominal weighting factor greater than 0.50. Hence use of the 100% + 50% + 10% load points would be insufficient. |
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4 In the case of the C1 test cycle, as a minimum, one load point from each of the rated, intermediate and idle speed sections should be used. The examples below give some of the possible combinations of load points which may be used together with the respective revised weighting factors:
C1 test cycle
| Speed |
Rated |
Intermediate |
Idle |
| Torque |
100% |
75% |
50% |
10% |
100% |
75% |
50% |
0% |
| Nominal weighting factor |
0.15 |
0.15 |
0.15 |
0.1 |
0.1 |
0.1 |
0.1 |
0.15 |
| Option H |
|
0.38 |
|
|
0.25 |
|
|
0.38 |
| Option I |
|
|
|
0.29 |
|
0.29 |
|
0.43 |
| Option J |
0.27 |
0.27 |
|
|
|
|
0.18 |
0.27 |
| Option K |
0.19 |
0.19 |
0.19 |
0.13 |
|
0.13 |
|
0.19 |
| Plus other combinations incorporating at least one load point at each of rated, intermediate and idle speeds |
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5 Examples of calculation of revised weighting factors:
For Option A:
75% load: revised value is calculated as: 0.5 x (1/(0.5 + 0.2)) = 0.71
50% load: revised value is calculated as: 0.2 x (1/(0.5 + 0.2)) = 0.29
For Option F:
75% load: revised value is calculated as: 0.25 x (1/(0.05 + 0.25 + 0.3 + 0.3)) = 0.38
Note: The revised weighting factors are shown to 2 decimal places. However, the values to be applied to NOx Technical Code equation 18 should be to the full precision. Hence in the Option F case above the revised weighting factor is shown as 0.38 although the actual calculated value is 0.384615...
Consequently, in these examples of revised weighting factors the summation of the values shown (to 2 decimal places) may not sum to 1.00 due to rounding.
APPENDIX 3
DETERMINATION OF POWER SET POINT STABILITY
1 To determine set point stability, the power coefficient of variance should be calculated over a 10-minute interval, and the sampling rate should be at least 1-Hz. The result should be less than or equal to five percent (5%).
2 The formulae for calculating the coefficient of variance are as follows:
Where,
%C.O.V. power coefficient of variance in %
S.D. standard deviation
Ave Average
N total number of data points sampled
Xi, Xj ith, jth value of power data point in kW
i index variable in standard deviation formula
j index variable in average formula
3 As an example, over the 10-minute sampling period, power is sampled at 1-Hz. This results in 600 data points being collected with values of X1, X2, X3...X600 and N is thus 600. The calculations would then be:
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