Thanks - autobloggreen.com for this  interesting "Greenie" news
   My Dad & I put "Browns' Gas" makers on our cars  back in the 80's
 They worked poorley and like all "perpetual motion machines" or EVERY scientest would  have one on thier car. 
 Christopher Haase
 Summary of  article:
 Global Energy Options and H to-go   claims to have done testing on a variety of engines ranging from a Chevrolet  pickup with a 5.3L V-8 to a Freightliner truck with Detroit Diesel engine and  seen improvements in fuel efficiency ranging from 33 percent to almost 73  percent....