When people talk about “driving a lemon“, they generally mean “lemon” to mean a defective automobile. A US patent granted in 1990 to Robert D. Whitworth describes a “Process for purifying limonene for fuel and the like“. A more detailed description, from the patent document:
A plant source fuel is disclosed per se and as a blend constituent for conventional petroleum fuels along with a process for producing same. Limonene obtained from citrus and other plants when distilled and treated to avoid formation of gums is blendable with conventional petroleum fuels up to about 20 volume percent to form blends that meet the standards for such fuels.
The patent was assigned to Lemco Energy, Inc. of Greenville, South Carolina, a company that has not yet prospered wildly or perhaps at all.
(Thanks to investigator Kurt Verkest for bringing this to our attention.)
BONUS: “Car glass antifoggant wet tissue with lemon flavor”, Chinese patent application 2012. The document specifies [auto-translated into English]:
1 A 1 lemon smell rotten antifogging agent automobile glass wipes; consisting of a mixture of cotton spunlace and composition; material and its percentage in the mixed solution of citric acid I ~ 2%, Tween -802 to 5%, 2-3% silicone oil, 2 to 5 percent oleic acid, polyethylene glycol esters I ~ 2%, glycerol dimer 2 ~ 3%, carbomer f 3% and the balance deionized water….