| 123 / | HD | INTERNAL-COMBUSTION ENGINES | 
| 434 | DF | CHARGE FORMING DEVICE (E.G., POLLUTION CONTROL) {29} | 
| 445 | DF | .~ Fuel injection system {5} | 
| 446 | DF | .~.~ Fuel pump flow regulation {4} | 
| 448 | DF | .~.~.~ Sequential distributor {3} | 
| 449 |  | .~.~.~.~ Rotary and reciprocating distributor |