fire up vs work up

fire up

verb
  • To excite; to infuse with energy. 

  • Of an engine or similar, to start. 

  • To ignite. 

  • To launch; to run. 

work up

verb
  • To raise; to excite; to stir up. 

  • To give (a patient) a general medical examination to assess health and fitness. 

  • To develop. 

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