Isooctane is burned with 120% theoretical air in a small three-cylinder turbocharged
engine.
a) Calculate fuel air ratio and equivalence ratio;
b) Find the constant pressure adiabatic flame temperature of isooctane burned in dry air.
It can be assumed that the reactants are at a temperature of 700 K after the
compression stroke (sensible enthalpy of isooctane at 700 K is 116851 kJ/kmol);
c) To reduce formation of NOx, it is desired to reduce this maximum temperature to
2200K. This is done by exhaust gas recycling (EGR). Calculate the percentage of
EGR needed to reduce maximum combustion temperature to 2200K. Exhaust gas,
that consists mostly of N2, CO2, and H2O, will be approximated as all nitrogen at a
temperature of 1000K in the intake. Note using EGR%= mEGR/(ma+mf+ mEGR)ď´100%
