ANNEX VIICONFORMITY OF PRODUCTION ASSESSMENT FOR EXHAUST AND NOISE EMISSIONS

1.

For verifying the conformity of an engine family, a sample of engines shall be taken from the series. The manufacturer shall decide the size (n) of the sample, in agreement with the notified body.

2.The arithmetical mean X of the results obtained from the sample shall be calculated for each regulated component of the exhaust and noise emission. The production of the series shall be deemed to conform to the requirements (‘pass decision’) if the following condition is met:

X+ k. S≤ Lmath

S is standard deviation, where:

S2=∑x− X2∕n− 1math
X

the arithmetical mean of the results obtained from the sample

x

the individual results obtained from the sample

L

the appropriate limit value

n

the number of engines in the sample

k

statistical factor depending on n (see table below)

n

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

k

0,973

0,613

0,489

0,421

0,376

0,342

0,317

0,296

0,279

0,265

0,253

0,242

0,233

0,224

0,216

0,21

0,203

0,198

If n ≥ 20 then k=0,860∕nmath.