Exhaust gas is gas which occurs as a result of combustion of fuel such as gasoline/petrol or diesel. It is discharged to atmosphere through an exhaust pipe. Although much of it is harmless carbon dioxide, part of it is noxious or toxic substances, such as carbon monoxide (CO), hydrocarbons, nitrogen oxides (NOx), and particulate substances. Diesel exhaust has a characteristic smell.
Diesel fuel is a specific fractional distillate of fuel oil (mostly petroleum) that is used in a diesel engine invented by German engineer Rudolf Diesel, and perfected by Charles F. Kettering.
Diesel is produced from petroleum, and is sometimes called petrodiesel when there is a need to distinguish it from diesel obtained from other sources.
Packard diesel motors were used in aircraft as early as 1927, and Charles Lindbergh flew a Stinson SM1B with a Packard Diesel in 1928.