3.3.13. System of greasing of the engine
Viscosity of engine oil
As viscosity is called degree of fluidity of engine oil. Fluidity of oil changes depending on temperature. With increase in temperature it is diluted. It influences firmness and resistibility of a greasing film. At a cold it becomes viscous, thus its fluidity decreases and increases внутренее resistance of a friction.
At the cold engine oil should be liquid enough not to overload a starter and that it could get in the course of engine start probably quickly to all places of greasing. It demands application of engine oil with such viscosity which whenever possible changes at temperature changes a little.
Fluidity or viscosity is equivalent to an internal friction of oil and is designated on system SAE (Society of Automobile Engineers), as for example, SAE 30, SAE 10 etc. Great numbers SAE have dense oils, small numbers – liquid. But viscosity at all does not characterise lubricant properties of oil.
Universal (all-weather) oils should be applied to engine Primera. All-weather oils have that advantage that приспособленны to temperature conditions (summer / winter). All-weather oils are made on the basis of liquid one-seasonal oil (for example, 15 W). Thanks to a so-called thickener oil is stabilised in a hot condition, so in any service conditions созраняются its lubricant properties. The letter "W" in designation SAE means suitability of oil to operation in winter conditions.
Oil of an easy course
Oils of an easy course are understood as all-weather oils with the additive of the means reducing factor of a friction which can provide decrease in the expense of fuel to 2 percent. Oils of an easy course have low viscosity (for example, 10 W-30). In their basis unusual oils (synthetic oils) lie. At purchase of oil of an easy course follows be convinced of, whether it is authorised to application by company NISSAN.
Engine oil 5W-20 approaches only for very cold climatic zones. Do not apply at long high-speed trips. For moderate climatic zones engine oil 10W-40 or 20W-50 is recommended.
As scopes of the next SAE-classes are crossed, it is possible not to pay attention to short-term fluctuations of temperature.
The engine oil specification
Basically only HD-oils are resolved for modern engines. HD-oils are the alloyed oils, greasing which properties are considerably improved thanks to the additive various chemically актичных substances. These additives provide the best anticorrosive protection, the best resistibility to the oxidation phenomena, in particular reduction of propensity to formation of adjournment in картере, the improved properties of stabilisation of the viscosity, clearing and dissolving properties. Clearing and dissolving additives not only reduce formation of adjournment in the engine, but also simultaneously possess ability of dissolution of adjournment both their and other pollution in the engine is thin to divide and keep in a suspension that provides possibility plum of all pollution at oil change.
The HD-oil grade is defined on system API (API: American Petroleum Institute). The European manufacturers also adhere to this system.
The designation consists of two letters. The first letter characterises диапозон applications: S – Service, it is intended for petrol engines, C – Сommercial, it is intended for diesel engines.
The second letter designates a grade in alphabetic order.
The premium oils under API-specification CE for diesel engines are.
The engine oils having accurate instructions of the manufacturer about application in diesel engines, it is forbidden to use in petrol, and in diesel engines. In this case on packing the double designation (for example, SF/CD) is underlined.
For Primera with diesel engines engine oils – SD approach.
The oil expense
At internal combustion engines the oil expense is understood as the expense of that quantity of oil which is spent as a result of combustion process. It is not necessary to mix the expense of oil with the leak of oil occurring because of негерметичности oil картера, covers of a head of cylinders etc.
The normal expense of oil occurs because of combustion of its small amounts in cylinders, because of tap of products of combustion and particles from a friction. Besides it oil is spent because of heats and a high pressure to which it is exposed in the engine.
Further the oil expense is influenced by service conditions, a driving manner, and also industrial admissions. The oil expense should make the maximum 1,0 l/1000 of km.