Chemistry in cars

Introduction:
Diesel fuel is a mixture of hydrocarbons obtained by distillation of crude oil. The important properties, which are used to characterize diesel fuel, include certain number (or certain index), fuel volatility, density, viscosity, cold behavior, and sulfur content. Diesel fuel specifications differ for various fuel grades and in different countries.

Main part: Diesel fuel is used in the diesel engines found in most freight trucks, trains, buses, boats, and farm and construction vehicles. Diesel fuel powers the vehicles that we use to produce and transport nearly all of our food and all of the other products we make and buy. Some cars and small trucks and boats also have diesel engines.
Diesel fuel is also used in diesel engine-generators to generate electricity. Many industrial facilities, large buildings, institutional facilities, hospitals, and electric utilities have diesel generators for backup and emergency power supply. Most remote villages in Alaska use diesel generators for their electricity.
The cleaner diesel fuel program significantly reduces sulfur content, creating immediate health benefits, and allowing engine manufacturers to begin using advanced emissions control systems that further reduce harmful emissions. The diesel program regulations are located in 40 CFR Part 80 subpart I.
Heating oil and diesel fuel are closely related products called distillates. The main difference between the two fuels is that diesel fuel contains less sulfur than heating oil. Approximately 12 gallons of distillate are produced from each 42-gallon barrel of crude oil. Of these 12 gallons of distillate, less than 2 gallons have a high-sulfur content, which can only be sold as heating oil.
In the past, diesel fuel contained high quantities of sulfur, which is considered harmful to the environment when burned through combustion. Because diesel fuel requires additional processing to remove sulfur, it is more costly to produce than heating oil.
In the United States, stringent emission standards have been adopted with the transition to ultra-low sulfur diesel (ULSD). In June 2006, the U.S. Environmental Protection Agency reduced the allowable level of sulfur in highway diesel fuel by 97%, as part of a program to reduce emissions from trucks