liquefied petroleum gas vs throttle

liquefied petroleum gas

noun
  • A mixture of propane and butane with traces of some other gases, which is kept in a liquid state at high pressure in metal bottles, and used as a source of gas for cooking, heating and as a fuel in internal combustion engines in vehicles. 

throttle

noun
  • A valve that regulates the supply of fuel-air mixture to an internal combustion engine and thus controls its speed; a similar valve that controls the air supply to an engine. 

  • The lever or pedal that controls this valve. 

verb
  • To utter with breaks and interruption, in the manner of a person half suffocated. 

  • To have the throat obstructed so as to be in danger of suffocation; to choke; to suffocate. 

  • To control or adjust the speed of (an engine). 

  • To breathe hard, as when nearly suffocated. 

  • To cut back on the speed of (an engine, person, organization, network connection, etc.). 

  • To strangle or choke someone. 

How often have the words liquefied petroleum gas and throttle occurred in a corpus of books? (source: Google Ngram Viewer )