Figure 9.11 shows, first, the theor

Figure 9.11 shows, first, the theoretical results of
burning a hydrocarbon fuel and, second, the actual
combustion results. The top part of the figure is
ideal but the lower part is the realistic result under
normal conditions. Note that this result is prior to
any further treatment, for example by a catalytic
converter.
Figure 9.12 shows the approximate percentages of
the various exhaust gas emissions. The volume of
pollutants is small but, because they are so poisonous,
they are undesirable and strong legislation now exists
to encourage their reduction. The actual values of
these emissions varies depending on engine design,
operating conditions, temperature and smooth running, to name just a few variables.
Table 9.1 lists the four main emissions that are
hazardous to health, together with a short description
of each