A four-cylinder, 2.5-liter, four-stroke cycle SI engine with a compression ratio operates at 3200 RPM. Peak cycle temperature is 2227°C, peak cycle pressure is 6800 kPa, and exhaust pressure is 101...

A four-cylinder, 2.5-liter, four-stroke cycle SI engine with a compression ratio operates at 3200 RPM. Peak cycle temperature is 2227°C, peak cycle pressure is 6800 kPa, and exhaust pressure is 101 kPa. The engine operates at part throttle with inlet air at 60°C and 75 kPa. An exhaust residual remains in the cylinders at the end of the exhaust stroke. In addition, 12% EGR at exhaust temperature and pressure is diverted back into the intake manifold, where it mixes with the inlet air before the intake valve.

Calculate:

(a) Exhaust temperature during exhaust stroke. [°C]

(b) Exhaust residual before EGR is added. [%]

(c) Cylinder temperature at the start of compression stroke. [°C]

(d) Theoretical design ratio of exhaust valve diameter to intake valve diameter.