Engine lubrication system. Purpose, principle of operation, operation
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Engine lubrication system. Purpose, principle of operation, operation

Not a single ICE is capable of operating without an engine lubrication system. This overview describes the purpose of the system, its malfunctions and recommendations for maintenance.

Purpose of the engine lubrication system

A car engine is the main unit that drives a vehicle. It consists of hundreds of interacting parts. Almost all of its elements are exposed to strong heating and frictional forces.

Without proper lubrication, any motor will quickly break down. Its purpose is a combination of several factors:

  • Lubricate parts to reduce wear on their surface during friction;
  • Cool hot parts;
  • Clean the surface of parts from small chips and carbon deposits;
  • Prevent oxidation of metal elements in contact with air;
  • In some unit modifications, oil is a working fluid for adjusting hydraulic lifters, timing belt tensioners and other systems.
Engine lubrication system. Purpose, principle of operation, operation

Heat removal and removal of foreign particles from the motor elements occurs due to the constant circulation of liquid through the oil line. Read about the effect of oil on the internal combustion engine, as well as the selection of material for high-quality lubrication. in a separate article.

Types of lubrication systems

These are the types of lubrication systems:

  • With pressure. For this, an oil pump is installed. It creates pressure in the oil line.
  • Spray or centrifugal. Often in this case, the effect of a centrifuge is created - the parts rotate and spray oil throughout the entire cavity of the mechanism. Oil mist settles on parts. The lubricant flows by gravity back into the reservoir;
  • Combined. Most often, this type of lubricant is used in the engines of modern cars. Oil is supplied to some components of the internal combustion engine under pressure, and to some by spraying. Moreover, the first method is aimed at forced lubrication of the most important elements, regardless of the operating mode of the unit. This method allows for more efficient use of the engine oil.

Also, all systems are divided into two key categories:

  • Wet sump. In these versions, the oil is collected in a sump. The oil pump sucks it in and pumps it through the channels to the desired unit;
  • Dry sump. This system is equipped with two pumps: one pumps, and the other sucks in oil flowing into the sump. All oil is collected in a reservoir.

Briefly about the pros and cons of these types of systems:

Lubrication system:AdvantagesDisadvantages
Dry sumpA car manufacturer can use a motor with a low height; When driving on slopes, the motor continues to receive the proper portion of cool lubricant; The presence of a cooling radiator provides better cooling of the internal combustion engine parts.The cost of a motor with such a system is many times more expensive; More parts that can break.
Wet sumpFew actuators: one filter and one pumpAs a result of the active operation of the engine, the oil can foam; The lubricant splashes heavily, due to which the engine may experience a slight oil starvation; Although the sump is at the bottom of the engine, the oil still does not have time to cool in it due to the large volume; When driving on a long slope does not suck in enough lubricant, which can cause the motor to overheat.

Device, principle of operation of the lubrication system

The classic system has the following structure:

  • Hole on top of the motor for replenishing the lubricant volume;
  • The drip tray in which all the oil collects. There is a plug at the bottom that is designed to drain the oil during replacement or repair;
  • The pump creates pressure in the oil line;
  • A dipstick that allows you to determine the volume of oil and its condition;
  • Oil intake, presented in the form of a pipe, put on the pump connection. Often it has a small mesh for coarse oil cleaning;
  • The filter removes microscopic particles from the lubricant. Thanks to this, the internal combustion engine receives high-quality lubrication;
  • Sensors (temperature and pressure);
  • Radiator. It is found in many modern dry sump motors. It serves to cool the used oil more efficiently. In most budget cars, this function is performed by the oil pan;
  • Overflow valves. Prevents oil from returning to the reservoir without completing a lubrication cycle;
  • Highway. In most cases, it is made in the form of grooves in the crankcase and some parts (for example, holes in the crankshaft).
Engine lubrication system. Purpose, principle of operation, operation

The principle of operation is as follows. When the engine starts, the oil pump automatically starts to work. It supplies oil through the filter through the cylinder head channels to the most loaded units of the unit - to the bearings of the crankshaft and camshaft.

Other timing components receive lubrication through slots at the crankshaft main bearing. The oil flows by gravity into the sump along the grooves in the cylinder head. This closes the circuit.

Engine lubrication system. Purpose, principle of operation, operation

In parallel with the lubrication of the key parts of the unit, oil seeps out through the holes in the connecting rods and then splashes onto the piston and the cylinder wall. Thanks to this procedure, heat is removed from the pistons, and the friction of the O-rings on the cylinder is also reduced.

However, many motors have a slightly different principle for lubricating small parts. In them, the crank mechanism breaks the drops into oil dust, which settles on hard-to-reach parts. In this way, they receive the necessary lubrication thanks to the microscopic particles of lubricant formed.

The diesel engine lubrication system additionally has a hose for the turbocharger. When this mechanism works, it gets very hot due to the exhaust gases that spin the impeller, so its parts also need to be cooled. Turbocharged gasoline engines have a similar design.

In addition, watch the video on the importance of oil pressure:

Engine oil system, how does it work?

How a combined wet sump lubrication system works

The principle of operation of this circuit has the following sequence. When the engine starts, the pump draws oil into the engine oil line. The suction tube has a mesh that removes large particles from the grease.

Oil flows through the filter elements of the oil filter. Then the line is distributed to all units of the unit. Depending on the modification of the internal combustion engine, it can be equipped with spray nozzles or grooves in key executive parts.

Engine lubrication system. Purpose, principle of operation, operation
1. Oil filler pipe
2. Fuel pump
3. Oil supply pipe
4. Oil outlet pipe
5. Centrifugal oil filter
6. Oil filter
7. Oil pressure indicator
8. Oil filter bypass valve
9. Radiator tap
10. Radiators
11. Differential valve
12. Safety valve for radiator section
13. Oil sump
14. Suction pipe with intake
15. Oil pump radiator section
16. Supply section of the oil pump
17. Reducing valve of the delivery section
18. Cavity for additional centrifugal oil cleaning

The entire unused volume of oil that goes to the KShM and timing, due to which, in a running engine, lubricant is sprayed onto other parts of the unit. All working fluid is returned by gravity to the reservoir (sump or tank). At this point, the oil cleans the surface of the parts from metal chips and burnt oil deposits. At this stage, the loop is closed.

Oil level and its meaning

Particular attention should be paid to how much oil is in the engine. In models with a wet sump, the level indicated by the notches on the dipstick must not be allowed to rise or fall. If the value is low, the motor will receive insufficient lubricant (especially when driving downhill). Even if the parts are lubricated, the heated pistons and cylinders will not cool, which will lead to overheating of the motor.

The lubrication level in the motor is checked with the engine off after a short warm-up. First, wipe the dipstick with a rag. It is then placed back in place. By removing it, the driver can determine how much oil is in the sump. If it is less than necessary, you need to replenish the volume.

If the permissible value is exceeded, the excess oil will foam and burn out, which will negatively affect the operation of the internal combustion engine. In this case, it is necessary to drain the liquid through the plug at the bottom of the sump. Also, by the color of the oil, you can determine the need for its replacement.

Engine lubrication system. Purpose, principle of operation, operation

Each motor has its own displacement of lubricant. This information is contained in the vehicle's technical documentation. There are engines that require 3,5 liters of oil, and there are those that need a volume of more than 7 liters.

Differences between petrol and diesel engine lubrication systems

In such motors, the lubrication system works in almost the same way, since they have a common structure. The only difference is the brand of oil used in these units. The diesel engine heats up more, so the oil for it must meet the following criteria:

There are three brands of oil:

Engine lubrication system. Purpose, principle of operation, operation

Each of them has one base, but its own set of additives, on which the oil resource depends. This parameter affects the frequency of replacement. Synthetics have a longer period, semi-synthetics are in second place, and mineral oil at the end of the list.

However, not every motor will run on synthetics (for example, older motors need a less fluid material for a thicker oil film). Recommendations for the type of lubricant and the regulations for its replacement are indicated by the manufacturer of the transport.

As for two-stroke engines, in such modifications there is no crankcase, and the oil is mixed with gasoline. Lubrication of all elements occurs due to the contact of the oily fuel located in the motor housing. There is no gas distribution system in such internal combustion engines, so such a lubricant is sufficient.

There is also a separate lubrication system for two-stroke engines. It has two separate tanks. One contains fuel and the other contains oil. These two fluids are mixed in the air intake cavity of the motor. There is another modification in which grease is supplied to the bearing from a separate reservoir.

This system allows you to adjust the oil content in gasoline in accordance with the engine operating mode. Whichever way the lubricant is supplied, in a two-stroke it is still mixed with fuel. That is why its volume must be constantly replenished.

Recommendations for the operation and maintenance of the lubrication system

The durability of the engine depends on the efficiency of the engine lubrication system. For this reason, she needs constant maintenance. This procedure is carried out at each stage of the maintenance of any car. If some parts and assemblies can be given less attention (although the safety and reliability of transport requires due attention to all systems), then negligence in changing the oil and filter will lead to costly repairs. In the case of some machines, it is cheaper to buy a new one than to start an engine overhaul.

Engine lubrication system. Purpose, principle of operation, operation

In addition to the timely replacement of consumables, the owner of the vehicle is expected to competently operate the power unit itself. When starting the engine after a long idle time (5-8 hours is enough), all the oil is in the sump, and there is only a small oil film on the mechanism parts.

If at this moment you give the motor a load (start driving), without proper lubrication, the parts will quickly fail. The fact is that the pump takes some time to push the thicker oil (because it is cold) along the entire line.

For this reason, even a modern engine needs a little warm-up so that the grease gets to all the units of the unit. This procedure will take no longer in winter than the driver has time to remove all the snow from the car (including from the roof). Cars equipped with the LPG system make this procedure easier. The electronics will not switch to gas until the engine has warmed up.

Particular attention should be paid to engine oil change regulations. Many rely on mileage, but this indicator does not always accurately indicate the frequency of the procedure. The fact is that even when a wound-up car is in a traffic jam or gets into a jam, the oil still gradually loses its properties, although the car can drive quite a bit.

Engine lubrication system. Purpose, principle of operation, operation

On the other hand, when the driver often drives long distances on the highway, in this mode the oil wastes its resource longer, even if the mileage has already been covered. Read how to calculate engine hours here.

And what kind of oil is better to pour into the engine of your car is described in the following video:

Engine oil system, how does it work?

Some malfunctions of the lubrication system

Most often, this system does not have a large number of faults, but they are manifested mainly by an increase in oil consumption or its low pressure. Here are the main faults and how to fix them:

Malfunction symptom:Possible malfunctions:Solutions:
Increased oil consumptionThe tightness of the filter is broken (badly screwed); Leakage through gaskets (for example, a crankcase gasket); Pallet breakdown; Crankcase ventilation clogged; Timing or KShM malfunctions.Replace the gaskets, check the correct installation of the oil filter (they could have installed it unevenly, from which it did not completely twist), to repair the timing, KShM or clean the crankcase ventilation, you should contact a specialist
System pressure droppedThe filter is heavily clogged; The pump is broken; The pressure reducing valve (s) is broken; The oil level is low; The pressure sensor is broken.Filter replacement, repair of faulty parts.

Most faults are diagnosed by visual inspection of the power unit. If oil smudges are observed on it, then this part needs to be repaired. Often, in the event of a severe leak, a stain will constantly form under the machine.

Some repair work requires partial or complete disassembly of the motor, so in such cases it is better to trust a specialist. Especially if a malfunction of the KShM or timing is detected. However, with proper maintenance, such malfunctions are extremely rare.

Questions and answers:

What is the engine lubrication system for? The lubrication system reduces friction between engine parts, ensures the removal of carbon deposits and fines, and also cools these parts and prevents them from corrosion.

Where is the engine oil tank located? In wet sump systems, this is the sump (under the cylinder block). In dry sump systems, this is a separate reservoir (an oil can is drawn on the lid).

What types of lubrication systems are there? 1 wet sump (oil in the pan); 2 dry sump (oil is collected in a separate reservoir). Lubrication can be operated by spraying, pressure injection or in combination.

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