An SI engine operates on an Otto cycle at 3800 RPM, with maximum cycle temperature and pressure of 3100 K and 7846 kPa. The engine has a compression ratio of 9.8:1, and immediately after combustion there is 0.000622 kg of exhaust gas in each cylinder. During exhaust blowdown, the average mass flow rate through the single exhaust valve is 0.218 kg/sec. At the end of blowdown, cylinder pressure is reduced to exhaust pressure of 101 kPa. Calculate: (a) Temperature in cylinder at end of exhaust blowdown. [K] (b) Mass of exhaust gas in cylinder at end of blowdown. [kg] (c) Crank angle when exhaust valve opens. [° bBDC]

Question

An SI engine operates on an Otto cycle at 3800 RPM, with maximum cycle temperature and
pressure of 3100 K and 7846 kPa. The engine has a compression ratio of 9.8:1, and immediately after combustion there is 0.000622 kg of exhaust gas in each
cylinder.
During exhaust
blowdown, the average mass flow rate through the single exhaust valve is 0.218 kg/sec. At
the end of blowdown, cylinder pressure is reduced to exhaust pressure of 101 kPa.
Calculate:
(a) Temperature in cylinder at end of exhaust blowdown. [K]
(b) Mass of exhaust gas in cylinder at end of blowdown. [kg]
(c) Crank angle when exhaust valve opens. [° bBDC]