impulsion vs propulsion

impulsion

noun
  • The act of impelling or driving onward, or the state of being impelled; the sudden or momentary agency of a body in motion on another body; also, the impelling force, or impulse. 

  • Influence acting unexpectedly or temporarily on the mind; sudden motive or influence; impulse. 

propulsion

noun
  • The action of driving or pushing, typically forward or onward; a propulsive force or impulse. 

How often have the words impulsion and propulsion occurred in a corpus of books? (source: Google Ngram Viewer )