Internal combustion engines not coming within the terms of the definition of some one of the following internal-combustion engine subclasses. This subclass contains patents relating to cycles or modes of operation not hereinafter provided for or in which the cycle or mode of operation is not definitely determined by the structure disclosed and will not ordinarily contain patents relating to definite mechanical structure.
(1) Note. Given mechanical structures not provided for in structural subclasses, but operating upon a definite and determined cycle of operation provided for in this classification, are classified in miscellaneous functional or cycle subclasses, such as 65, and subclasses indented thereunder, and 311+, and indented subclasses, etc.
(2) Note. The use of unconventional fuels as found in this
subclass are commonly hazardous and toxic waste and their destruction or containment is found in Class 588, Hazardous or Toxic Waste Destruction or Containment.
