Page 153 - Automobile Mechanical and Electrical Systems Automotive Technology Vehicle Maintenance and Repair (Vehicle Maintenance Repr Nv2) by Tom Denton

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Engine systems 137

Figure 2.113 There are a variety of covers on all engines. On this diagram yellow represents
the oil sump and other areas, green coolant passages, red exhaust ports and blue inlet air.
(Source: Ford Media)

rear of the engine, another crankshaft oil seal is fi tted to a casing that is bolted to
the engine and located by dowels.
The sump contains baffl es to prevent excessive oil movement or surge. This
maintains a good supply of oil around the area of the oil pick-up.
Attached around the engine are auxiliary components and subsystems for
lubrication, cooling, ignition, fuel, air, exhaust and electrical systems.

2.2 Engine lubrication

2.2.1 Friction and lubrication

Lubrication is the introduction of a substance, called a lubricant (e.g. oil to
create an oil fi lm), between two moving contact surfaces, to reduce friction.
This reduction of friction greatly reduces the wear of the surfaces and thus
lengthens their service life. It also reduces the energy required for the movement.
Lubrication is important in all moving parts of the vehicle but the engine has the
greatest need.
Under a microscope, even the smoothest engine components have a surface
that looks very rough. If these surfaces made contact they would rub together,
overheat and destroy themselves. To prevent this happening, engines have a Key fact
lubrication system that pumps or drips a constant supply of oil on all the moving Under a microscope, even the
metal components. smoothest engine components have
a surface that looks very rough.
Although the basic function of a lubricant is to reduce friction and wear, it may
also perform a number of other functions. It carries off generated heat and it
helps to form a gas-tight seal between piston rings and cylinders. It also carries
away harmful combustion waste products. Lubrication helps to control corrosion
by coating parts with a protective fi lm. A detergent added to the lubricant helps
to removes sludge deposits.