7 INTERNAL COMBUSTION ENGINES FOR MACHINE OPERATION AND REPLACEMENT PARTS THEREFORE; CONVERSION APPLIANCES AND DEVICES FOR HOT GASES, NAMELY, CATALYTIC CONVERTERS FOR TREATMENT OF HOT GASES IN POWER PLANTS, STEAM ENGINES AND INDUSTRIAL OPERATIONS; CATALYTIC CONVERTERS CONTAINING CATALYST SUBSTRATES FOR INTERNAL COMBUSTION ENGINES; CATALYTIC CONVERTERS CONTAINING CATALYTIC SUBSTRATES FOR THE TRACTION OR PROPULSION SYSTEMS OF LAND VEHICLES, AIRCRAFT AND WATERCRAFT; PARTS OF ENGINES FOR NON-LAND VEHICLES, AIRCRAFT AND WATERCRAFT, NAMELY, PRIME MOVERS AND DRIVE MOTORS