Page 163 - 05. Subyek Teknik Mesin - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

2
Engine systems 147

Figure 2.130 Gerotor pump driven by the crankshaft

Figure 2.131 Vane pump

rotates, the vanes sweep around inside the pump housing. The pump chambers
increase in volume as the vanes move away from the housing walls, and reduce
in volume as the vanes approach the walls. Oil is carried between the vanes and
the pump housing from the inlet port to the outlet port.
Most modern engines now use the crankshaft to give a direct drive to the
oil pump. These pumps are of the gerotor or crescent design, and are fi tted
around the front of the crankshaft. This arrangement is used on many overhead Key fact
camshaft engines because it provides a low position for the pump. Most modern engines now use the
crankshaft to give a direct drive to
the oil pump.
2.2.6 Standards
2.2.6.1 SAE
The Society of Automotive Engineers (SAE) ( Fig. 2.132 ) has established a
numerical code system for grading motor oils according to their viscosity
characteristics. SAE viscosity grades include the following, from low to high
viscosity: 0, 5, 10, 15, 20, 25, 30, 40, 50 or 60. The numbers 0, 5, 10, 15 and 25
are suffi xed with the letter W, designating their ‘winter’ or cold-start viscosity,
at lower temperature. The number 20 comes with or without a W, depending