Lubrication circuit

 An engine is made up of a whole bunch of moving metal parts. Rubbing against each other generates heat due to the friction generated. For the various mechanisms to last over time, they must be oiled, ie there is a film of lubricant between the parts. So let's see the principle of lubrication as well as the elements that need to be oiled.

Lubrication circuit

Lubrication consists of applying a layer of oil between two metal parts, this prevents these parts from rubbing against each other, but for this the choice of viscosity according to the temperatures is vital. This allows both not to wear the parts (by rubbing they "crumble") but also to limit the heat, because any friction generates heat (rub your hands quickly, you will see that it happens quickly !). And in the case of an engine, the heat generated can be very high...

Let's look at the so-called wet sump system (almost all engines) where the oil is stored in the latter, at the base of the engine under the crankshaft. Conversely, there is the dry system, click here for more information.

Note that there is generally in addition a water/oil exchanger that I have not indicated here, a place where water and oil meet (separated by a partition all the same ...). This helps heat the oil faster when the engine is cold and it reduces the oil temperature when the engine is hot.

The oil present in the housing is sucked in by the oil pump (supplied by the engine via a belt), the lubricant then goes through a filter in order to retain any particle which could be there. Then, ducts/cavities in the high engine/cylinder/cylinder head allow the oil to be directed under pressure to the places which require being lubricated. These conduits are internal to these rooms and therefore cannot be seen from the outside. What oil is consumed (the causes can be diverse, there is then blue smoke: more info here ).

The main parts that must be lubricated are the crankshaft (its bearings), the camshaft, the valves, the possible turbo (axis bearing), the connecting rods and the pistons.