Engine lubricants petrol engines

The most common of the other specifications are those with the prefix MIL, issued by the US military authorities. M1L-L-2104E approximates to the API CE rating for diesel lubricants, although it also relates to petrol engines that require API SE performance. M1L-L-46152D covers oils for both diesel and petrol engines, and approximates to API SG/CC (Figure 52.5). 

Another important set of performance specifications is produced by the European Vehicle Manufacturers Association, known by its initials CCMC. The CCMC rating G-1 corresponds roughly to API SE, and G-2 to API SF. G-3 (comparable to M1L-L-46152B, for petrol engines only) covers fuel-efficient and light-viscosity lubricants... 

To meet these aims for light vehicle lubricant formulations, each engine test has a characteristic criterion or set of criteria, some examples are given in Table 17.2. These light engine lubricant tests are used for either or both petrol- and diesel-fuelled light vehicles as components of API or ACEA test procedures. 

Table 17.2 Engine lubricant tests for light vehicles, petrol/diesel ...

The A/B petrol and diesel engine lubricant categories are all stable, stay-in-grade lubricants and may be unsuitable for some engines, the owner man-ual/handbook should be consulted, where ... 

Samples of lubricant obtained from the piston ring of a petrol engine under cold start conditions are very different from the sump lubricant condition. Samples from the first operating hour show substantial fuel and water dilution which cause precipitation of additive from the lubrication formulation with multiple phase formation. The physical performance properties of these lubricant samples are drastically changed, e.g.. Base Number drops from 10 to less than 2, anti-oxidancy is reduced and viscometric properties are changed. Implications for short vehicle journeys and temperature distributions within the piston assembly are discussed. 

Samples of these lubricants were taken from the first ring groove of a Fetter W-1 petrol engine running under the IP 176 procedure for 15, 30,45, 60, 90, 120 and 180 minutes. Multiple test run samples using a fresh lubricant charge for each test and each lubricant formulation were bulked ... 

It is important to realise that the uses of the fractions depend on their properties. For example, one of the lower fractions, which boils in the range 250-350 °C, is quite thick and sticky and makes a good lubricant. However, the petrol fraction burns very easily and this therefore makes it a good fuel for use in engines. 

IBP IChemE IDI IEA IFP IGL ILSAC Initial boiling point. Institution of Chemical Engineers (U.K.). indirect injection (diesel). International Energy Agency. Institute Francais du Petrole (France). Investigation Group Lubricants (CEC). International Lubricant Standards Approval Committee. Association of AMA and JAMA to develop unified lubricant standards. Specification GF-1 was issued in 1991 for use in North America. CCMC has declined to participate at this time. 

A characteristic of automotive petrol lubricant specifications is the inclusion of the performance properties of each previous category, thus the SM specification gives full protection for SJ or SL requirements. This differs from the diesel engine specifications which usually, but not necessarily, include the performance properties of earlier specifications. Table 17.9. 

One hundred percent ethyl alcohol as a spark ignition engine fuel or alcohol substituted at low levels in petrol can interact with and cause problems with the additive pack in the current type of lubricant formulations. Reformulation of lubricants to deal with the effects of these fuels will be necessary. However, the relevant technology is available from South America where, for example, Brazil has operated light vehicles on total alcohol fuels for over a decade. 

A3/B3 for high-performance petrol and diesel light vehicle engines and/or for extended drain intervals where specified by the engine manufacturer and/or for year-round use of low-viscosity lubricants, and/or for severe operating conditions as defined by the engine manufacturer. 

A6/B6 for use at extended drain intervals in high-performance petrol and diesel light vehicle engines designed for low-friction, low-viscosity lubricants with a high-temperature/high-shear rate viscosity of 2.9-3.5 mPa.s. 

Uses Rust inhibitor, corrosion inhibitor, metal deactivator, demulsifier in petrol, and syn. lubricants, engine oils, gear oils, greases, hydraulic oils, metalworking, turbine oils... 

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