Reference no: EM13835796

Problem 1: An eight-cylinder spark-ignition engine with a compression ratio of 9 develops 200 hp at 4500 rpm. The engine displacement equals 348 in^3. The temperature and pressure at the beginning of the compression process are 70 °F and 14.7 psia, respectively. Consider a cold air-standard analysis. Determine the following:

• Thermal efficiency.
• The net work per cycle (Btu/lbm) per cylinder.
• The temperature (°R) and pressure (psia) at each point in the cycle.

Problem 2: An air-standard Otto cycle has a compression ratio of 9. The temperature and pressure at the beginning of the compression process are 300 K and 100 kPa, respectively. The heat addition per unit mass of air is 1350 kJ/kg. Assume that specific heats vary with temperature. Determine the following:

• The net workper unit mass of air (kJ/kg).
• The thermal efficiency.
• The mean effective pressure (kPa).

Problem 3: The compression ratio of a cold air-standard Diesel cycle is 15. The state of the air at the beginning of the compression stroke is 15 °C, 100 kPa. The heat transfer in the combustion process is 1800 kJ/kg. Determine the following:

• The temperature (°C) and pressure (kPa) at the end of the compression stroke.
• The work (kJ/kg) during the constant pressure heat addition.
• The cutoff ratio.
• The thermal efficiency.