Motor oil
It also neutralizes acids that originate from fuel and from oxidation of the lubricant (detergents), improves the sealing of piston rings, and cools the engine by carrying heat away from moving parts.
While studying the possible healing powers of crude oil, Dr. Ellis was disappointed to find no real medicinal value, but was intrigued by its potential lubricating properties.
Lubricating oil creates a separating film between surfaces of adjacent moving parts to minimize direct contact between them, decreasing frictional heat and reducing wear, thus protecting the engine.
[5] Coating metal parts with oil also keeps them from being exposed to oxygen, inhibiting oxidation at elevated operating temperatures preventing rust or corrosion.
In some engines oil is sprayed through a nozzle inside the crankcase onto the piston to provide cooling of specific parts that undergo high-temperature strain.
Portable electricity generators and "walk behind" lawn mowers use four-stroke engines similar to those in automotive vehicles and use standard motor oils.
The Noack volatility test (ASTM D-5800) determines the physical evaporation loss of lubricants in high temperature service.
This exclusive recommendation led to the elimination of informative charts depicting climate temperature range along with several corresponding oil viscosity grades being suggested.
This applies to short trips of under 15 kilometres (10 mi), where the oil does not get to full operating temperature long enough to boil off condensation, excess fuel, and other contamination that leads to "sludge", "varnish", "acids", or other deposits.
The engine user can, in replacing the oil, adjust the viscosity for the ambient temperature change, thicker for summer heat and thinner for the winter cold.
Engine designs are evolving to allow the use of even lower-viscosity oils without the risk of excessive metal-to-metal abrasion, principally in the cam and valve mechanism areas.
Group I base stocks are composed of fractionally distilled petroleum which is further refined with solvent extraction processes to improve certain properties such as oxidation resistance and to remove wax.
Examples of group V base stocks include polyolesters (POE), polyalkylene glycols (PAG), and perfluoropolyalkylethers (PFPAEs) and poorly refined mineral oil.
[22] The SP standard refers to a group of laboratory and engine tests, including the latest series for control of high-temperature deposits.
Current API service categories include SP, SN, SM, SL and SJ for gasoline engines.
A key new test for GF-4, which is also required for API SM, is the Sequence IIIG, which involves running a 3.8 litres (230 cu in), GM 3.8 L V-6 at 125 hp (93 kW), 3,600 rpm, and 150 °C (302 °F) oil temperature for 100 hours.
[30] The ACEA (Association des Constructeurs Européens d'Automobiles) performance/quality classifications A3/A5 tests used in Europe are arguably more stringent than the API and ILSAC standards[citation needed].
The JASO T904-MA and MA2 standards are designed to distinguish oils that are approved for wet clutch use, with MA2 lubricants delivering higher friction performance.
A 1989 American Society for Testing and Materials (ASTM) report stated that its 12-year effort to come up with a new high-temperature, high-shear (HTHS) standard was not successful.
In the view of this writer, this redefinition did not occur because the automotive lubricant market knows of no field failures unambiguously attributable to insufficient HTHS oil viscosity.
BMW regularly develops new specs to meet the increasing demands of the EPA emission standards and MPG requirements as well as new engines.
Another aspect for after-treatment devices is the deposition of oil ash, which increases the exhaust back pressure and reduces fuel economy over time.
Some of these additives include: Some molybdenum disulfide containing oils may be unsuitable for motorcycles which share wet clutch lubrication with the engine.
[38] Due to its chemical composition, worldwide dispersion and effects on the environment, used motor oil is considered a serious environmental problem.
[50] One US gallon (3.8 L) of used oil can generate a 32,000 m2 (8 acres) slick on surface water, threatening fish, waterfowl and other aquatic life.
[49] According to the U.S. EPA, films of oil on the surface of water prevent the replenishment of dissolved oxygen, impair photosynthetic processes, and block sunlight.
[51] Improperly disposed used oil ends up in landfills, sewers, backyards, or storm drains where soil, groundwater and drinking water may become contaminated.
[55] The USDA National Center for Agricultural Utilization Research developed an Estolide lubricant technology made from vegetable and animal oils.
Independent testing not only shows biosynthetic oils to be among the highest-rated products for protecting engines and machinery; they are also bio-based, biodegradable, non-toxic and do not bioaccumulate in marine organisms.
[59] Biodegradable motor oils based on esters or hydrocarbon-ester blends appeared in the 1990s followed by formulations beginning in 2000 which respond to the bio-no-tox-criteria of the European preparations directive (EC/1999/45).
