Dry sump

The engine lubrication is to reduce friction between moving parts of the engine of internal combustion engines, as well as the dissipation of heat from the bearings and the piston by means of lubricating oil. In addition to possible wear particles, combustion residues and other contaminants are flushed into the oil filter. For the execution of lubrication systems, various methods are used.

• 3.2 Dry sump lubrication

Consumption lubrication

Mixed lubrication

In the mixed lubrication, the lubricating oil is added to the fuel in the prescribed mixing ratio ( 1:25 / 1:50, etc.). The oil contained in the two-stroke mixture passes to the lubrication points and is burned with. The mixture lubrication is still used in small two-stroke engines ( lawnmower / chainsaw / mopeds ). For cars, this system came up in the late 1980s for use - the best known are probably the GDR Zweitakter like Trabant, Wartburg or Barkas.

The advantage is the ease of preparation of the mixture ( just type oil for fuel and a little shake). A disadvantage is the separation of the two components with long life; This can also be by the lubricating oil can not be completely prevented added special additives. Although this can be remedied by re- shaking or by stirring; but this is forgotten or overlooked, it can start and concentricity problems result to engine damage.

Fresh oil lubrication

In this system, also used in two-stroke engines, the lubricant is carried along separately admixed to the fuel by a pump and then also ( using fresh oil automatic transmission, for example in the DKW F102 ) with burnt. Advantages are always fresh preparation of the mixture and the exact dosage in comparison to mixed lubrication, whereby the lubricating properties can be always kept constant and reduced oil consumption and the exhaust gas quality is improved. The disadvantages are the slightly higher system costs.

The fresh oil lubrication is also used for large two-stroke marine diesel engines for cylinder lubrication. The crankshaft and the other lubrication points here with a wet sump lubrication system (see below) lubricated.

Splash lubrication

In simple four-stroke engines (very common lawn mower and generator engines) often comes this very simple lubrication system for use. For motors with vertical crankshaft located on a separate gear ( often combined with speed controller) several " blades ". For engines with horizontal crankshaft connecting rod bearings on the other hand, there is a " finger." The blades or the " finger " running in oil and hurl it through the crankcase, thereby ensuring sufficient lubrication is ensured. The disadvantage is that here can be used no oil filter and lubrication of certain stock ( vaKurbelwellen and connecting rod bearings ) can be ensured only by an increased bearing play.

Circulation lubrication

Application: four-stroke engine; in the vast majority of today car and motorcycle engines this lubrication system is employed. Here, the lubricant is necessary carried below the crankshaft in the oil pan. The oil pump draws oil, transported it to the oil filter and then through channels to the lubrication points; in vehicles that can reach high longitudinal and lateral accelerations, several distributed in the sump oil pumps are used, so that in every driving situation oil can be sucked. By the crankshaft, makes its rotary movement for an additional fluidization of the oil mist in the cylinder crankcase, and thus the cooling of the piston, and maintaining the oil film on the piston path of the cylinder. The dripping oil is collected in the oil pan again. The pressure lubrication is also known under the name of wet sump lubrication, as a demarcation for dry sump lubrication.

Dry sump lubrication

Application: four-stroke engine; Similarly to the fresh oil lubrication here the lubricant is carried in a separate container and conveyed through a pressure pump ( first oil pump ) to the lubrication points. The dripping lubricating oil is in contrast to the forced lubrication by means of a second return pump ( suction pump ) extracted from the oil sump and conveyed back to the oil tank. The return pump has in principle to the lubricating oil reliably to pump a greater capacity than the vacuum pump in any driving situation from the crankcase into the oil reservoir.

When the Porsche Boxster, Cayman, Panamera V6 and 911 ( types 996 and 997 except GT2, GT3 and Turbo) one is used " integrated" dry sump lubrication: serves as an oil reservoir, the oil pan of the engine, on the separate oil tank is omitted In the. new motors of types 911, Boxster and Cayman from 2009 model year are incorporated to ensure an adequate oil supply in the oil pan even four recirculation pumps. , the security of a real dry sump lubrication is not achieved by the method used by Porsche since 2010 in all non -GT models.

The advantages of more sophisticated dry sump lubrication are:

• It can be used larger quantities of oil, without the engine needs to be extended by an enlarged oil pan down. The usually located below the crankshaft oil pan can even be significantly reduced or eliminated, which reduces the overall height of the engine.
• By actionable lower engine height, the motor can be mounted lower, allowing a lower vehicle center of gravity and thus better cornering stability. In addition, reduced to a front engine through the hood flatter, the air resistance and thus fuel consumption.
• Due to the greater possible amount of oil, the cooling capacity can be improved and the change intervals can be extended.
• The lubricating oil reservoir need not be located on or in the motor, but the oil tank may be arranged at any point in the vehicle. This is advantageous to optimize in very tight engine compartments or to the weight distribution.
• Even in an inclined position ( ATVs, aircraft) and at high centrifugal force ( cornering in racing ) is a constant oil pressure and hence the engine lubrication is ensured by the large stock in the oil reservoir.

The disadvantage of dry sump lubrication is that they complex design is by the second oil pump and the separate container than the pressure circulation lubrication. Therefore, it is usually only used in low-slung sports cars, motorcycles or all-terrain vehicles. Vehicles with dry sump lubrication, eg Porsche 911 with the above restriction, the Mercedes 450 SEL 6.9, the Alfa Romeo Montreal, the BMW M1, the Audi R8 ( Spyder ), the Mercedes -Benz SLS AMG, Maserati Ghibli, all TVR models with the so-called six -speed motor, the current Corvette C6 Z06 Corvette C6 ZR1 and Corvette C6 Grand Sport, only Coupe / switch as well as the bikes from KTM, Harley -Davidson, Triumph Rocket III, Buell, the new motorcycles (from 2004) of the K - series and F- series models and the enduro and enduro motorcycles from Yamaha ( XT 660 R / Z / X and XT 1200 Z Super Tenere and Yamaha TDM ) and Honda ( Honda NX 650 Dominator ).

Due to the two oil pump lubrication system more complex and additional to a potential interference will be extended, but there is no redundancy. Due to the failure of one (no matter which ) oil pump breaks down the lubricating oil circuit together.

The oil level must be read in contrast to pressure -feed lubrication media while the engine to idle on the dipstick the oil reservoir. In the Corvette C6 ( Z06 and ZR1 ) only needs the oil to a temperature of approx. 80 ° C are warmed up. Then the engine is turned off, and after about 5-20 minutes, the oil level can be measured. The Porsche Boxster models (model 987 from 2004) and Cayman have no conventional dipstick more, but only an electronic oil level indicator.