Labyrinth: the basic idea behind the new three-section crankcase designed for the Audi A4.
This section shows the oil cooler (2) in which the engine oil is cooled in a 1.6 liter engine. All Audi engines are equipped with such an oil cooler. The cooled oil is supplied via connection unit "1" - and the next unit - via the oil cooler and cools the engine oil by means of the radiator fins visible in this photo. The oil is forced through the oil filter (3).
Oil pump
At full throttle, the oil pump pumps about 30 liters of oil per minute through the engine:
- In a four-cylinder engine, the intermediate shaft drives the crankshaft, the lower part of which drives the oil pump.
- In a 16-cylinder engine, the oil pump is mounted on the crankshaft in front of the engine in the direction of travel.
- The way the pumps work in our Audi engines is also different.
- The four-cylinder engine has a gear oil pump. Two meshing gears of the same size simply draw oil from the suction side to the discharge side.
- The six-cylinder engine is lubricated by a rotary oil pump of the Eaton system. In this case, the gear with external teeth is placed inside the gear with internal teeth (these are both rotors). By specially shaping and eccentrically positioning the inner rotor, an effect is achieved in which new spaces with reduced pressure are constantly created when both gears rotate together. In this way, the motor oil is sucked in. From the rotating gears, the oil is pressed to the outlet side of the pump and from there into the lubrication channels.
Oil temperature
For the engine to "feel good", the oil temperature is crucial. The Audi driver can only get this information from the built-in additional instruments. Let's compare the engine temperature at the oil filter flange or at the oil pump for fun; the temperature of the lubricant there is the lowest. On the contrary, on the piston rings the oil temperature reaches 300°C.
If you drive a car with an oil temperature gauge: Audi considers 145°C in the crankcase as the maximum permissible temperature. Although this is conditional on the presence of high-quality oil according to the instructions.
Too low an oil temperature is also harmful to the engine. In this case, the oil has not yet reached its full lubricating capacity. If possible, after starting a cold engine, do not raise the engine speed above 3500 rpm until the oil has warmed up to approximately 60°C. The starting point is the fact that the oil needs twice as much time as the coolant to reach its operating temperature.
Oil pressure
If your Audi A4 has a built-in oil pressure sensor or if you can connect an oil pressure sensor to the engine in a workshop instead of an oil pressure switch, you can monitor its pressure yourself within the accuracy of the measuring device. Test condition: oil temperature 80°C. The following values should be obtained:
- Oil pressure at idle: 1–2.5 bar.
- Oil pressure at 3000 rpm: 3–5 bar.
Oil pressure is also well controlled without a device in Audi. You will learn more about this in the chapter Tools and instruments.
This article was copied from the website audimanual