Is there a such thing as a fuel/air rifle?

I know there are air rifles as opposed to conventional guns. I wonder if a gun that combines the propellant efficiency of a pure air gun, & the power of an exothermic reaction(pure flammables pack more energy than explosive compounds that currently drive ammunition) viable firearm innovation. It seems like there's some potential there. You have the stopping power of a "real" gun, & the raw material efficiency of a pure air gun. You wouln't need any cartridges, or smokeless powder. I'm wondering if car fuel could do the trick, or kerosine. I'm sure the effect on the barrel is a consideration. I'm thinking it can have the same basic function as a conventional air gun, except the incoming air can help spray in a stoiciometric amount of fuel into the action chamber. There should also be an ignition source like a spark or glow plug. The resulting combustion & expansion can help boost the bullet/pellet's veloicity. If it works well, the same safety regulations would apply as w/ a full blown rifle. Do such rifles exist?