123 / | HD | INTERNAL-COMBUSTION ENGINES |
434 | DF | CHARGE FORMING DEVICE (E.G., POLLUTION CONTROL) {29} |
672 | DF | .~ Including exhaust gas condition responsive means {11} |
691 | DF | .~.~ Multiple sensors controlling group of cylinders {1} |
692 | .~.~.~ Controlling plural groups of cylinders |