AUTOMOTIVE AND GENERAL REPAIR PRODUCTS:MOTOR OIL

MOTOR OIL

The distillation of crude oil or coal tar produces high-boiling components that are commonly used as lubricants such as motor oil. Solvent extraction and hydrogen refining are used to remove unwanted components and to increase the percentage of saturated hydrocarbons present. Modern lubricants must have good viscosity and temperature characteristics to meet the requirements of modern internal combustion engines. Corrosion and oxidation inhibitors are also added to increase the service life of the engines.

The discovery of petroleum oil’s lubricant properties dates back to the 1850s, when it was discovered that oil was able to withstand high and low temperatures without losing its lubricant properties. In the late 1860s, a method of steam heat distillation of crude oil was used to obtain high-viscosity petroleum oil that was capable of withstanding the high heats associated with maintaining the lubrication of combustion engines of the era. Vacuum Oils Co., the forerunner of Mobile Corp., successfully marketed these petroleum lubricants to machinery owners to reduce wear and repair costs on expensive machinery used in millwork. These oils had extraordinary performance characteristics, such as the ability to reduce friction and wear, the ability to function dependably at temperature extremes, and the ability to withstand rigorous and lengthy engine operation without chemical breakdown. These properties would be invaluable in the new internal combustion engines of the time.

A machine’s sliding or rolling surfaces must be separated to avoid friction and severe wear. This was accomplished by using lubricants with viscosities. Lubrication exists as long as a continuous thick film of oil separates the solid surfaces at all the points of wear, cooling and preserving metal parts from oxidation. In the internal combustion engine, oil must reliably lubricate bearings within the crankcase, pistons, and piston rings at temperatures at which fuel is being burned within the cylinder. Since oils change viscosity with respect to temperature, the ideal oil will protect moving parts equally at all temperatures. The principle of hydrodynamic lubrication, or coating the metal surfaces with a film of oil that will ad- here to the surface, is essential to avoid piston wear in the engine. This thin coat of oil reduces friction and as a consequence the operating temperature of the engine, preserving the moving metal components in the engine.

Motor oils are hazardous to the environment and to humans having direct contact with them. Although motor oils can withstand greater temperatures than other petroleum products, such as gasoline, they are still highly flammable. Like most other petroleum distillates, motor oil is carcinogenic, mutagenic, and has adverse effects on the human reproductive system. Because of its higher boiling point, it is not a significant

inhalation hazard and tends not to be absorbed through the skin readily. Prolonged exposure can lead to contact dermatitis. Motor oil that has been used should be discarded with care to avoid environmental contamination. Motor oils are less dense than water and are immiscible with water. Environmental contamination from oil is problematic in that there is no natural mechanism to break down the oil, so it accumulates in sedimentary deposits and eventually finds its way into the food chain, causing toxic effects. A typical barrel of crude oil ends up as gasoline for cars, kerosene for aircraft, diesel fuel for heavy vehicles, and lubricant oil for engines. A myriad of everyday products use products or by-products of the refining process.