Division 6.13
Fuel consumption for a vehicle with a positive ignition engine fuelled by hydrogen:
F1For vehicles fuelled either with gaseous or liquid hydrogen, and with approval of the approval authority, the manufacturer may choose to calculate fuel consumption using either the equation for FC below or a method using a standard protocol such as SAE J2572.
The compressibility factor, Z, shall be obtained from the following table:
Table A7/2
Compressibility factor Z
| T (K) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 5 | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | ||
| p (bar) | 33 | 0,859 | 1,051 | 1,885 | 2,648 | 3,365 | 4,051 | 4,712 | 5,352 | 5,973 | 6,576 |
| 53 | 0,965 | 0,922 | 1,416 | 1,891 | 2,338 | 2,765 | 3,174 | 3,57 | 3,954 | 4,329 | |
| 73 | 0,989 | 0,991 | 1,278 | 1,604 | 1,923 | 2,229 | 2,525 | 2,810 | 3,088 | 3,358 | |
| 93 | 0,997 | 1,042 | 1,233 | 1,470 | 1,711 | 1,947 | 2,177 | 2,400 | 2,617 | 2,829 | |
| 113 | 1,000 | 1,066 | 1,213 | 1,395 | 1,586 | 1,776 | 1,963 | 2,146 | 2,324 | 2,498 | |
| 133 | 1,002 | 1,076 | 1,199 | 1,347 | 1,504 | 1,662 | 1,819 | 1,973 | 2,124 | 2,271 | |
| 153 | 1,003 | 1,079 | 1,187 | 1,312 | 1,445 | 1,580 | 1,715 | 1,848 | 1,979 | 2,107 | |
| 173 | 1,003 | 1,079 | 1,176 | 1,285 | 1,401 | 1,518 | 1,636 | 1,753 | 1,868 | 1,981 | |
| 193 | 1,003 | 1,077 | 1,165 | 1,263 | 1,365 | 1,469 | 1,574 | 1,678 | 1,781 | 1,882 | |
| 213 | 1,003 | 1,071 | 1,147 | 1,228 | 1,311 | 1,396 | 1,482 | 1,567 | 1,652 | 1,735 | |
| 233 | 1,004 | 1,071 | 1,148 | 1,228 | 1,312 | 1,397 | 1,482 | 1,568 | 1,652 | 1,736 | |
| 248 | 1,003 | 1,069 | 1,141 | 1,217 | 1,296 | 1,375 | 1,455 | 1,535 | 1,614 | 1,693 | |
| 263 | 1,003 | 1,066 | 1,136 | 1,207 | 1,281 | 1,356 | 1,431 | 1,506 | 1,581 | 1,655 | |
| 278 | 1,003 | 1,064 | 1,130 | 1,198 | 1,268 | 1,339 | 1,409 | 1,480 | 1,551 | 1,621 | |
| 293 | 1,003 | 1,062 | 1,125 | 1,190 | 1,256 | 1,323 | 1,390 | 1,457 | 1,524 | 1,590 | |
| 308 | 1,003 | 1,060 | 1,120 | 1,182 | 1,245 | 1,308 | 1,372 | 1,436 | 1,499 | 1,562 | |
| 323 | 1,003 | 1,057 | 1,116 | 1,175 | 1,235 | 1,295 | 1,356 | 1,417 | 1,477 | 1,537 | |
| 338 | 1,003 | 1,055 | 1,111 | 1,168 | 1,225 | 1,283 | 1,341 | 1,399 | 1,457 | 1,514 | |
| 353 | 1,003 | 1,054 | 1,107 | 1,162 | 1,217 | 1,272 | 1,327 | 1,383 | 1,438 | 1,493 |
In the case that the required input values for p and T are not indicated in the table, the compressibility factor shall be obtained by linear interpolation between the compressibility factors indicated in the table, choosing the ones that are the closest to the sought value.