Typical examples of deflagrations are combustion of a gas-air mixture in a gas stove or a fuel-air mixture in an internal combustion engine , a rapid burning of a gunpowder in a firearm or pyrotechnic mixtures in fireworks . Typical examples of deflagrations are the combustion of a gas-air mixture in a gas stove or a fuel-air mixture in an internal combustion engine , and the rapid burning of gunpowder in a firearm or of pyrotechnic mixtures in fireworks .