fire up vs set afire

fire up

verb
  • To ignite. 

  • To excite; to infuse with energy. 

  • Of an engine or similar, to start. 

  • To launch; to run. 

set afire

verb
  • Synonym of set on fire 

How often have the words fire up and set afire occurred in a corpus of books? (source: Google Ngram Viewer )