Correct use of lubricating oils for agricultural machinery

Man has been using processes to reduce friction for a long time. There are reports of lubrication on a sled that belonged to Ra-Em-Ka (king of Egypt BC). On that occasion, the use of tallow was discovered to reduce friction between the sled and the contact surface, facilitating its movement. In the Middle Ages, animal fat was used to lubricate the opening mechanisms of creaky gates and also the wheels of carriages.

FUNCTIONS OF LUBRICATING OILS

The use of lubricants has the main function of minimizing contact between moving parts, thus avoiding greater wear (reduction of friction) and heat generation (engine cooling) and, in addition to these benefits, it allows cleaning the engine and maintaining it. clean, protection against corrosion and formation of acids inside, noise reduction, helps seal the combustion chamber and contributes to reducing fuel consumption.

Automotive lubricating oils are mineral base oils obtained through distillation or re-refining, synthetic base oils produced by chemical reactions and compound or semi-synthetic oils.

The main characteristics of lubricating oils are viscosity, viscosity index and density. Viscosity characterizes the resistance of a fluid to flow. Therefore, the more viscous it is, the more difficult it is to drain, so it will have a greater ability to remain between the pieces. The viscosity of the lubricant is influenced by temperature. The viscosity index refers to the variation in viscosity as a function of temperature, the higher the index, the lower the variation in viscosity when subjected to an increase in temperature. Density is the mass of a given volume of oil at a given temperature and serves as an indicator of contamination or deterioration of a lubricant.

ADDITIVES

Additives are natural, modified or synthesized substances added to lubricants, with the function of modifying, providing or enhancing properties of base oils, in order to provide greater effectiveness to the lubricants. The quality of the oil is associated with the level of additives it receives, with multiviscoses being more additive and complete than monoviscoses. There are several types of additives and the main ones are: pour point lowerers (which have the function of reducing the freezing temperature of the oil, caused by the crystallization of the paraffins present in it); extreme pressure agents (have the role of preventing metal-to-metal contact of surfaces in relative movements when subjected to extreme pressure); anticorrosives (neutralize acids), antirust, antioxidants (slow down the oxidation of lubricating oils), antifoams (minimize the formation of foams), dispersants and alkaline detergents (prevent the formation of deposits of combustion and oxidation products); viscosity index improvers (reduce the tendency for viscosity to vary with temperature variation); friction modifiers (reduce the coefficient of friction, resulting in lower fuel consumption).

Finished automotive lubricating oil is the same as the composition of a base oil + additives.

TYPES OF LUBRICANT OILS

There are several ways to classify lubricants, we can classify them by their origin, viscosity, the type of engine to be applied, the physical state of the lubricant, its density and countless other factors, therefore, there are entities responsible for its distinction.

Due to the need to follow standards for the manufacture of lubricants for internal combustion engines, there are international classification entities, such as the Society of Automobile Engineers (SAE), the American Petroleum Institute (API) and the Association of European Automobile Manufacturers (Acea) . (see box with classifications).

It is worth remembering that the label on lubricant packaging always specifies the type of oil contained and that the machine manual indicates the correct lubricant in terms of viscosity (SAE) and performance (API). The recommended lubricants undergo several tests by the manufacturers of your machine until the ideal one is chosen and, therefore, there is a need to use the indicated lubricant.

MAINTENANCE OF LUBRICANTS

Maintenance on engines, mainly related to lubrication, when carried out at the correct time, brings benefits to the machine, however, it is necessary to carry it out in three different ways, in order to provide the best performance.

Maintenance can be carried out preventively weekly or every 50 hours of work, monthly, or every 250 hours, semi-annually, or 500 hours, annually, or every thousand hours worked. Therefore, it operates according to a periodicity, for example, changing the engine's lubricating oil depending on the period stipulated by the manufacturer. It can be in order to correct a fault, generally carried out from the moment a problem is detected and a quick intervention is needed so that the machine is briefly released to carry out operations. These failures can be, for example, loss of lubricating oil due to damage to the oil-carrying component (hydraulic hose), such as a leak. Another form of maintenance is predictive, which is carried out by monitoring the chemical and physical conditions of the lubricant, observing the presence of contamination by water molecules, ammonia and/or the presence of ferrous particles in the sample.

The advantages of periodic, corrective and, mainly, predictive maintenance carried out correctly will be lower maintenance costs, savings on lubricants, extended useful life of components, reduced replacement material costs, greater availability of equipment, control and analysis of the equipment wear.

ROUTINES IN THE USE OF LUBRICANT OILS

Some routines are essential to maintain the quality of the lubricant and, consequently, the results of its application. One of these routines is to check the machinery oil level every ten hours, observing whether the level is within the safe working range. This must be done with the vehicle on level ground, with the engine turned off and preferably with the engine cold. . When during measurements it shows a level below the recommended range, it indicates a leak or high consumption of the machine and, therefore, correction must be taken quickly.

The oil change must be carried out in accordance with the manufacturer's specifications together with the requirements described in the machine manual and must occur in accordance with the service time stipulated by the manufacturer of automotive machines such as tractors, harvesters and sprayers. Failure to follow this recommended periodicity may result in a series of risks, as as the lubricant becomes senile, its chemical characteristics will change and prolonged use may cause damage to the engine systems, which will result in increased maintenance costs. . Continued use of the lubricant will increase its viscosity mainly due to the accumulation of insoluble products.

EXCHANGE PROCEDURE

ENGINE OIL

Extraction must be carried out with the self-propelled machine on level ground, switched off and preferably after the engine has reached normal working temperature, as the hot oil drains easily. You must wait ten minutes for maximum removal before replacing. There is another method which consists of using suction pumps to check the oil level dipstick, however, this process has the problem of not completely removing it. The change must be made with an oil with the same characteristics and preferably from the same brand, as use with different chemical levels can promote chemical reactions that will result in wear, corrosion, oxidation, causing harm to the engine or organic components.

OIL CONSUMPTION

The consumption of lubricating oil is directly related to the work regime and the way the engine was worked at the beginning of its operation, a period called running-in. When an engine has been well run-in, the power used is proportional, so the greater the engine's demand, the greater the consumption of both diesel oil and lubricants. Therefore, special attention to the initial period of the engine until its running-in will be the factor that will result in savings throughout the engine's useful life.

IMPORTANT DETAILS

Observing some details is of fundamental importance to ensure the protection of the machine. The lubricating oil must be of the best quality and as recommended by the manufacturer. The correct way to check the oil level is essential and must occur with the tractor level, daily before operation and must not be completed when the level is between the maximum and minimum marks. Higher oil consumption in the first 100 hours is normal during break-in, however, each machine has an acceptable level of consumption.

Regarding the running-in of the tractor, in the first 100 hours the engine must work with load - up to 75% of its capacity - and at low rotation, using the nominal rotation specified for each model, and special care with choosing the appropriate implement for your tractor. capacity. The tractor should not be used for light duty during break-in.

Engine running-in consists of making the gears as perfect as possible and in agricultural machines it is different from other automotive vehicles. Many people think that smoothing means printing at low speed, when in fact the machine needs a high speed. The machine must be subjected to work with implements that require high power, such as the initial preparation of soil, as this allows the tractor to have a continuous torque requirement. The minimum working time is 50 hours, which can be extended to 200, noting that, if extended, lighter work must be carried out and the first oil and filter change must be within 100 hours.

Another factor to be analyzed refers to the sizing of the implement, where the tractor is taken to a speed known as critical, relating the implement, speed and force of the tractor. There are other precautions that must be observed, such as choosing lighter gears when traveling. Another method of break-in is through dynamometer brakes, where these are connected to the power take-off, allowing intense loads to be transmitted to the engine throughout the break-in period, which lasts around ten hours of work. This method is quite advantageous as it is possible to control the speed drops at programmed intervals of 200rpm. Therefore, properly running-in the engine in the first few hours of its useful life means obtaining greater cost-benefit and greater longevity of the machine.