PRIN. OF INTERNAL COMBUSTION ENGINES - OD1619 LESSON 2/TASK 2
b. Combination Splash and ForceFeed System (figure 61 on the previous page). In
the combination system, oil is delivered to some parts by means of splash and to
other parts through oil passages, under pressure from a pump in the crankcase. The
main and the camshaft bearings are usually the items that are force fed while the
connecting rods are fitted with dippers that supply oil to the rest of the engine
by splash. Some configurations use small troughs under each connecting rod, kept
full by small nozzles that deliver oil under pressure from the oil pump. These oil
nozzles deliver an increasingly heavy stream as speed increases. At very high
speeds, these oil streams are powerful enough to strike the dippers directly. This
causes a much heavier splash so that adequate lubrication of the pistons and the
connecting rod bearings is provided at higher speeds. If a combination system is
used on an overhead valve engine, the upper valve train is lubricated by pressure
from the oil pump.
FIGURE 62. FORCEFEED LUBRICATION SYSTEM.
c. ForceFeed Lubrication System (figure 62). A somewhat more complete
pressurization of lubrication is achieved in the forcefeed lubrication system.
Oil is forced by the oil pump from the crankcase to the main bearings and the
76
Previous Page
