ACEA (Association des Constructeurs Européens d’Automobiles).
ACEA represents 16 major car manufacturers who update and develop the various engine oil categories (e.g. ACEA A3/B4), which set the requirements for individual oils. These categories describe the suitability of the respective engine oils for a specific type of motor and/or exhaust after-treatment technology.
Additives are oil-soluble substances that are added to mineral oils, mineral oil products and synthesis oils. They are tailored precisely for the oil type and their addition serves to change the properties of lubricants, fuels, heating oils, etc. This change in the physical or chemical attributes leads to a marked improvement of your engine oil, for example.
The undesirable chemical transformation of mineral and synthetic products (e.g. lubricants, fuels) in use and storage is referred to as aging. The process is triggered by reactions with oxygen (producing peroxides, hydrocarbon radicals). Heat, light and catalytic effects of metals and other contaminants speed up this oxidation. The process generates acids and sludge. Substances that protect from aging – antioxidants (AO) – serve to delay it.
A barrel is an international measure of capacity. This measuring unit has been in use in the mineral oil industry since the beginnings of oil extraction. The barrels used in the past were cleaned herring barrels that were filled with oil. These barrels had a capacity of exactly 158.99 litres. Even if a standard oil barrel can accommodate around 30% more oil these days, the measuring unit of 1 barrel = 42 US gallons = 159l has still been retained.
The base oil makes up the major portion of a lubricant product. Base oils can be engine oils and gear oils, but also lubricating greases, for example. The type and volume of the respective base oil depends on what a lubricant is meant to be used for. This is determined by the various behaviours of the oil in terms of viscosity, oxidation resistance, friction behaviour and the additives to be used.
The cetane number is a measure describing the ignitability of diesel fuels. The higher the number, the more combustible the diesel fuel, permitting quieter combustion. The cetane number shows how many volume percent of cetane are contained in a mixture with alpha-methyl naphthalene exhibiting the same ignition delay as the diesel fuel to be tested. It is determined as per DIN 51773 in Germany.
The density ρ of a mineral oil or related substance is the quotient of its mass m and volume V at a specific temperature t; it is a substance-specific property. It will increase in substances of the same type as their viscosity rises, and decrease as the quality of the refining level grows: DIN 51757
ρ = m/V
Extreme pressure lubricants are lubricating oils or greases containing EP ingredients (polar or metal-active additives and/or solid lubricants, etc.). These permit a greater load absorption capacity. The additives prevent metal surfaces from welding together, which may occur if two surfaces chafe against each other under high pressures or heavy loads. These high-pressure lubricants are for example used in engine oils, transmission oils, hydraulic fluids, etc.
The flashpoint is the lowest temperature at which a tested liquid in a crucible will give off so much vapour that the resulting vapour and air mixture in the crucible becomes ignitable by external ignition, flares up briefly and then goes out again.
Depending on whether the flashpoint is determined in an open or closed crucible, there are various standards exactly describing the respective test and testing requirements.
HTHSV (high temperature high shear viscosity) is the viscosity of a multi-grade engine oil at a specific high temperature and defined high shear speed in a defined measuring vessel by way of a standardized measuring method. This procedure is part of the ACEA classification with minimum requirements for the individual oil categories. The HTHS-viscosity for engine oils is normally determined at 150°C and a shear speed of 10⁶ s−¹. This is meant to simulate the high strain the engine oil is exposed to.
The engine oil classifications developed by the International Lubricants Standardization and Approval Committee (ILSAC) are modelled on the API classifications and were introduced for the Asian region.
Although both classifications (API and ILSAC) consider the chemical and physical requirements for the engine oil, amongst other aspects, there are still regional differences between engines, laws, external conditions and fuels that need to be taken into account accordingly.
Overview of the ILSAC engine oil specifications:
GF-1 – introduced in 1996, modelled on API: SH, obsolete, replaced by GF-2
GF-2 – introduced in 1997, modelled on API: SJ, obsolete, replaced by GF-3
GF-3 – introduced in 2001, modelled on API SL, obsolete, replaced by GF-4
GF-4 – introduced in 2004, modelled on API: SM, obsolete, replaced by GF-5
GF-5 – introduced in 2010, modelled on API: SN
GF-6 – in planning, introduction expected in 2020
Cold sludge accumulates in the engine crankcase. These deposits are formed from combustion products and condensate when the engine fails to reach its normal operating temperature, which is often the case with stop-and-go (short distances). The accumulation of cold sludge can lead to premature engine wear and engine damage. To prevent this, the following factors can be considered: operating conditions, engine oil quality, oil change intervals and fuel quality.
Low-viscosity oils are car engine or transmission oils that save fuel in comparison with conventional 15W-40 engine oils or 80W-90 transmission oils by reducing the friction in operation, enabling an easier engine start at low temperatures, and ensuring that the various assemblies are oiled through faster. These are the so-called fuel economy oils or also fuel efficiency oils. Friction can either be reduced by lowering the viscosity, by using specific synthetic base oils and/or by adding friction-reducing additives.
Requirements for fuel economy oils:
ACEA specification A1, B1, C1, C2 or API in conjunction with EC requirements.
The acronym SAPS stands for the first letters of the English terms sulphated ash, phosphorus, sulphur. A low SAPS engine oil is thus an oil with very low contents of these substances. Given their low tendency to form ashes, these oils are also referred to as low-ash oils. The need to use additives that form less ash for formulating a modern engine oil may sound quite simple, but developing such an engine oil is a real challenge for any lubricant manufacturer.
These need to be distinguished as follows:
Metalworking oils for cutting processes:
Collective term for cutting oils, grinding oils, drilling oils, honing oils, milling oils, etc. They are available in water-miscible and water-inmiscible versions. One standardized term for them is also "cooling lubricants". Their main tasks vary depending on the application: lubrication, cooling, friction and wear reduction, chip transport, corrosion protection, etc.
Metalworking oils for forming processes:
Collective term for forming oils, punching oils, drawing oils, deep drawing oils, cold forging oils, etc. These are only available in a water-inmiscible form. Their main tasks also vary depending on the application: lubrication, friction and wear reduction, corrosion protection, cooling, etc.
The NLGI grade expresses the relative hardness of a lubricating grease. Lubricating greases are graded in consistency classes on the scale of the National Lubricating Grease Institute (NLGI) in keeping with their worked penetration. To determine the worked penetration, a standardized test cone is allowed to penetrate a grease sample for 5 seconds that has been brought to 25°C and worked, and the penetration depth is measured in 1/10 mm. The greater the penetration depth, the softer the grease.
Friction improvers (friction reducers/friction modifiers) are fatty acids, fatty acid derivatives, organic amines, amine-phosphates, mild EP additives and many more.
Friction improvers are designed to lower and/or reduce friction losses or achieve a defined friction performance for the various lubricants. The various application areas in the mixed friction area include the avoidance of friction vibrations (e.g. at guiding ways), of so called slip-stick phenomena, or of noises with automatic transmissions, synchronizer rings and limited-slip differentials. But they are also used for fuel economy engine oils and the controlled friction performance of hydraulic transmission oils (UTTO, STOU) for systems with wet brakes and clutches.
accumulates as mineral oils age. Under the influence of air and water, mineral oil products can tend to form oxidants and polymerize. If this phenomenon intensifies, the oxidation products are no longer dispersed in the oil, they precipitate, and form sludge. Modern lean-burn gasoline engines may accumulate a black sludge under specific conditions (aka oil sludge). The influencing factors can include the engine type, operating conditions, nitrogen oxide formation, fuel, engine oil conception, oil change intervals, oil level, oil consumption, etc. There are special engine sludge tests for engine oils as a consequence.
The lubricity identifies the carrying capacity of a lubricant's lubricating film. It always needs to relate to specific conditions. These conditions can include the following factors: friction type, friction condition, material combination of the chafing bodies, lubrication of the contact surfaces, surface loading, speed and temperature. In the case of fluid friction, for example, only the viscosity is decisive for the carrying capacity, but with boundary friction also the erosion prevention capacity. Erosion prevention with the help of EP substances. There is no uniform measure for the lubricity for these reasons.
Lubricating greases are semi-solid to solid mixtures comprising a thickening agent (thickener), base oils and additives. The production process, thickener type and base oils used determine the properties (such as structure, consistency, temperature- and water-resistance, etc.) and thus also the application area of a lubricating grease.
Lubricating greases can be classed by various criteria, including the thickener type. An essential distinction is made between:
• metal soap lubricating greases consisting of fatty acids and metal bases as metal soap thickener (e.g. lithium thickener), and
• soap-free lubricating greases consisting of inorganic or organic thickeners (e.g. polyurea, bentonite)
Metal soap lubricating greases are used for many conventional applications, whereas soap-free lubricating greases lend themselves to special high-temperature applications, amongst others.
Water-inmiscible cooling lubricant for cutting metalwork. This is tasked with lubrication, heat dissipation, and thus cooling the tool and workpiece. But it can also take care of the chip transport if the cutting oil streams continuously. Thanks to the reduced friction, the cutting force required is smaller and the wear minimized, which has a positive effect on the surface quality, dimensional accuracy and lifetime of tools.
Cutting oils are usually mixed with a number of additives that lend them a high pressure stability or improve their ability to adhere to surfaces.
As a rule, cutting oils are used wherever the lubricating effect is more important than the cooling effect.
Synthetic lubricants were developed for particular technical application areas and special requirements. They offer more protection and functionality so that the engine will maintain an optimal performance over many years. In comparison with conventional mineral oils, synthetic lubricants are mostly purer and less contaminated.
In addition, they also have strengths in the following areas: high temperature stability, low temperature performance, evaporation loss, oxidation resistance (lifespan fulfilment), high pressure stability, viscosity-temperature behaviour, etc.
UTTO is a universal tractor transmission oil, also for wet brakes and hydraulics in farm tractors and construction machines, but not for engines. UTTO oils offer the advantage that many partly varying applications can be operated with one and the same lubricant. This leads to simplifications for the user in terms of storage and allocation. The manufacturer's instructions for required specifications and viscosity classes must be unfailingly complied with.
Compressor lubricating oils are often used to generate compressed air. This particularly happens in air compressors with oil lubricated pressure chambers and no injection cooling. Compressor lubricating oils can also be used in air vacuum pumps working against a higher than atmospheric pressure. DIN 51506 describes them with and without additives and divides them into groups:
Lubricating oil group:
For mobile air compressors and compressors whose compressed air serves to operate braking, tipping, signalling or conveyance facilities on vehicles – with compression end temperatures
VDL -> up to 220 °C
For air compressors with containers for storing the compressed air or with pipeline networks with compression end temperatures
VDL -> up to 220 °C
Anti-wear additives are lubricant additives designed to prevent chafing between metal surfaces moving against one another (e.g. in transmissions). They initially stick to the metal surface by virtue of their polarity. Once the temperature in the mixed friction area rises due to the friction, these additives are activated and either form chemical compounds at the friction points or ensure physical adsorption. This continuously creates new surfaces at the friction points that prevent or reduce the material abrasion by wear.
The viscosity is a measure for the thickness of a liquid. The higher the viscosity, the thicker the product, and the lower the viscosity, the thinner. High viscosities therefore form thick lubricating films and reliably protect gears and bearings from wear. Especially with engine oils, low viscosities mean less churning loss and thus a higher efficiency with lower fuel consumption. The operating forces in control gears grow with rising viscosity. This can lead to a worsening of the shift comfort if the wrong viscosity is selected.
The viscosity index is a mathematically calculated number on a conventional scale that characterizes the changes of a mineral or synthesis oil product's viscosity with the temperature. A high viscosity index marks a lower viscosity change with the temperature than a low viscosity index and vice versa. Calculation of the viscosity index from the kinematic viscosity: DIN ISO 2909, ASTM D 2270
Ball bearing greases are lubricating greases for lubricating roller bearings, mostly in the NLGI consistency classes 1-3. The lubrication thus reduces the contact between rolling and sliding surfaces in order to decrease the friction and wear in the bearing. Lithium-saponified lubricating greases are used in most cases today. Calcium-soap lubricating greases are also used for special application areas, e.g. with very strong water impact.
Heat transfer oil is a temperature- and oxidation-resistant mineral or synthesis oil with a high flashpoint that can be used as a heat carrier for cooling or heating. It is a means of heat transportation, so to speak. Important features are: initial boiling point, flashpoint, vapour pressure, fluidity and crack temperature.
The requirements for heat transfer oils Q are defined in DIN 51522.
Two-stroke engine oil is a special type of engine oil that is completely consumed in operation by burning up. Depending on the engine type, use, lubrication system, blendability, blending ratio, corrosion protection, cleaning effect, biodegradability etc., the following two-stroke engine oils are distinguished for lubricating two-stroke gasoline engines:
a) self-mixing (pre-dissolved)
b) non self-mixing (not pre-dissolved) for clean oil automatic (clean oil lubrication)
c) outboard engine oils
Depending on the lubrication system of the two-stroke engine, the required oil is either directly mixed in with the fuel or stored in a separate oil tank.
There are various performance classes for two-stroke engine oils such as the API TC, for example, which is mostly used in two-wheelers, or the NMMA (National Marine Manufacturing Association) TC-W3, which is mostly required by watercraft such as jet skis.
Secondary raffinates are used lubricating oils (waste oils) that have been recycled into secondary raffinates in a refinery. This is done by dewatering, cleaning, distillation, blending and other processes. Depending on the quality of the process technology, the properties of secondary raffinates can almost equal those of primary raffinates.