Figure 7-3. Manifold Heat Control Valve
gen are formed when the nitrogen and oxygen in the
unburned fuel. They are particulate in form (solid) and,
intake air combine when subjected to the high
like carbon monoxide, they are manufactured by
temperatures of combustion. Oxides of nitrogen are
insufficient oxygen in the combustion mixture and
harmful to all living things.
combustion chamber temperatures that are too low.
Hydrocarbons are harmful to all living things. In any
7-6. Controlling of Exhaust Emissions. The control
urban area where vehicular traffic is heavy, hydrocarbons
of exhaust emissions is a very difficult job. To eliminate
in heavy concentrations react with sunlight to produce a
carbon monoxide and hydrocarbon emissions, the
brown fog known as photochemical smog.
temperatures of the combustion chamber would have to
be raised to a point that would melt pistons and valves.
c. Oxides of Nitrogen (NOx). Oxides of nitro-
This Is compounded with the fact that oxides of nitrogen