Question

A 4 stroke, 6 cylinder diesel engine operates at 2000 rpm on a cold air standard Diesel cycle and has compression ratio of 22. At the beginning of the compression process the pressure is 95 kPa and the temperature is room temperature (25°C). If the maximum temperature in the cycle is not to exceed 1900-C, determine (a) the thermal efficiency and (b) the MEP.

Answer 1

The thermal efficiency of the diesel engine is 54.3% and the MEP is 91.59 kPa.

Step-by-step explanation:

To determine the thermal efficiency of the diesel engine, we need to use the equation for thermal efficiency:

Thermal Efficiency = 1 - (1 / Compression Ratio)^(γ - 1)

where γ is the specific heat ratio.

Substituting the given values, we have:

Thermal Efficiency = 1 - (1 / 22)^(1.4 - 1) = 0.543

To determine the MEP (Mean Effective Pressure), we need to use the equation for MEP:

MEP = (Maximum Pressure - Minimum Pressure) / (Compression Ratio - 1)

Substituting the given values, we have:

MEP = (1900 kPa - 95 kPa) / (22 - 1) = 91.59 kPa