Fig. 6. Nonetheless , the slower rate of heat release implies the lowered combustion temperature and thus reduces /w.
Fig. 8 shows the effect of EGR on the energy and availability balances at the medium load. While the fraction in the brake work in
Fig. 8a, as usually expected , is smaller than that of the indicated
work in Fig. 8b at this operating condition, the fraction of indicated
work in the total energy (the sum of brake work and the mechanical loss) is larger than that in the total availability because the total availability islarger than the total energy.The fraction of combustion irreversibility increases with the EGR ratio increasing from 0% to 12% due to the lowered flame temperature, but it decreases again with 17% EGR. This may be attributed to the fact that
there are more incompletely burned fuels, resulting in less combustion irreversibility. From Fig. 8, again, it can be seen that the
availability in the heat transfer loss and exhaust gas is smaller than
the energy in the heat transferred through the combustion chamber walls and in the exhaust gas.