MEPC 39/6/1

ANNEX

Page 28

Ta = temperature of the air in K

H4 = humidity of the intake air, g water per kg dry air (as determined by formula (10))

5.12.3.6 Diesel engines with Intermediate air coolers

For diesel engines with intermediate air coolers, the following alternative formula (14) shall be used:

.1 To take the humidity in the charge air into account, the following consideration is added.

Hsc = humidity of the charging air, g water per kg dry air in which:

Hsc = 6.220･P SC l00/(PC- P SC)

where:

Psc = saturation vapour pressure of the charging air, kPa

PC = charging air pressure, kPa

.2 If Ha ≧ Hsc, then Hsc shall be used in place of Ha in formula (14). In shin case, G EXHW in 5.5.2.3 shall be corrected as follows:

G EXHW corrected = GEXHW (5.5.2.3) (1 - (Ha - Hsc) / 1000))

.3 If Ha ＜ Hsc, then Ha in formula (14) shall be used as it is.

(14)

where:

Tsc = Temperature of the intercooled air

Tsc Ref = to be specified by the manufacturer

Note: For an explanation of the other variables, see formula (13).

5.12.4 Calculation of the emission mats flow rates

5.12.4.1 The emission mass flow rates for each mode shall be calculated as follows (for the raw exhaust gas):

Gas mass = u conc GEXHW (15)

or

Gas mass = v conc V EXHW (16)

or

MEPC 39/6/1

ANN EX

Page 29

Gas mass = w conc V EXHW

5.12.4.2 The coefficients u-wet, v-dry and w-wet shall he used as specified in table 5.

Table 5. Coefficients u, v, w

Note:the coefficient for u given in table 5 are correct values for an exhaust density of 1.293 only; for exhaust density *1 .293. u = w / density.

5.12.5Calculation of the specific emissions

5.12.5.1 The emission shall be calculated for all individual components in the following way:

(18)

5.12.5.2 The weighting factors and the number of modes (n) used in the above calculation are according to the provisions of 3.2.

5.12.5.3 The resulting average weighted NOx emission value for the engine as determined by formula (18) shall then be compared to figure 1 in 3.1 to determine if the engine is in compliance with regulation 13 of Annex VI.

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