Purposely Made
Tanks and naval ships may use the injection of fuel or special "fog oil" into exhaust tract to create smoke screens. Rather than burning, the oil normally evaporates and re-condenses at a particular droplet size, but under abnormal conditions it may catch fire or even produce a fuel-air explosion.
Cars extensively modified for visual appearance and not road use (stunts, ads, movies etc.) may be fitted with gasoline injectors in their exhaust systems, or even with small flamethrowers separate from the exhaust.
Read more about this topic: Back-fire
Famous quotes containing the word purposely:
“So much they scorn the crowd, that if the throng
By chance go right, they purposely go wrong.”
—Alexander Pope (1688–1744)
“I cannot see how a man of any large degree of humorous perception can ever be religious—except he purposely shut the eyes of his mind & keep them shut by force.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)