Power Plant Engineering

 Fig. 8.8. Full Pressure System.
This system finds favour from most of the engine manufacturers as it allows high bearing pres-
sure and rubbing speeds.
The general arrangement of wet sump lubrication system is shown in Fig. 8.9. In this case oil is
always contained in the sump that is drawn by the pump through a strainer.
To Bearings
Filter
Pressure
Regulator
Breather
Engine
Crankcase
Drum Plug
Wet Sump
Oil strainer
Oil Pump
 Fig 8.9. Wet sump lubrication system.

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POWER PLANT ENGINEERING
8.10.2 SOLID LUBRICANTS OR DRY SUMP LUBRICATION SYSTEM
Refer Fig. 8.10. In this system, the oil from the sump is carried to a separate storage tank outside
the engine cylinder block. The oil from sump is pumped by means of a sump pump through filters to the
storage tank. Oil from storage tank is pumped to the engine cylinder through oil cooler. Oil pressure may
vary from 3 to 8 kgf/cm
2
. Dry sump lubrication system is generally adopted for high capacity engines.
To
Bearing
Oil Pump
Engine Crankcase
Dry Sump
Strainer
Scavenging
Pump
Filter
Filter
Pressure
Valve
By Pass
Relief
Supply
Tank
Vent
Pressure
Relief
Valve
Oil
Cooler
Fig. 8.10. Dry Sump Lubrications System.
8.10.3 MIST LUBRICATION SYSTEM
This system is used for two stroke cycle engines. Most of these engines are crank charged, i.e.,
they employ crank case compression and thus, are not suitable for crank case lubrication. These engines
are lubricated by adding 2 to 3 per cent lubricating oil in the fuel tank. The oil and fuel mixture is
induced through the carburator. The gasoline is vaporized; and the oil in the form of mist, goes via
crankcase into the cylinder. The oil that impinges on the crank case walls lubricates the main and con-
necting rod bearings, and rest of the oil that passes on the cylinder during charging and scavenging
periods, lubricates the piston, piston rings and the cylinder.