Problem 42
How does a diesel engine differ from a gasoline engine?
Problem 43
How does the ideal Diesel cycle differ from the ideal Otto cycle?
Problem 44
For a specified compression ratio, is a diesel or gasoline engine more efficient?
Problem 45
Do diesel or gasoline engines operate at higher compression ratios? Why?
Problem 49
An ideal Diesel cycle has a maximum cycle temperature of \(2300^{\circ} \mathrm{F}\) and a cutoff ratio of \(1.4 .\) The state of the air at the beginning of the compression is \(P_{1}=14.4\) psia and \(T_{1}=50^{\circ} \mathrm{F}\). This cycle is executed in a four-stroke, eightcylinder engine with a cylinder bore of 4 in and a piston stroke of 4 in. The minimum volume enclosed in the cylinder is 4.5 percent of the maximum cylinder volume. Determine the power produced by this engine when it is operated at 1800 rpm. Use constant specific heats at room temperature.
Problem 50
An air-standard dual cycle has a compression ratio of 14 and a cutoff ratio of \(1.2 .\) The pressure ratio during the constant-volume heat addition process is \(1.5 .\) Determine the thermal efficiency, amount of heat added, the maximum gas pressure and temperature when this cycle is operated at \(80 \mathrm{kPa}\) and \(20^{\circ} \mathrm{C}\) at the beginning of the compression. Use constant specific heats at room temperature.
Problem 52
An air-standard Diesel cycle has a compression ratio of \(18.2 .\) Air is at \(120^{\circ} \mathrm{F}\) and 14.7 psia at the beginning of the compression process and at \(3200 \mathrm{R}\) at the end of the heataddition process. Accounting for the variation of specific heats with temperature, determine \((a)\) the cutoff ratio, \((b)\) the heat rejection per unit mass, and ( \(c\) ) the thermal efficiency.
Problem 54
An ideal diesel engine has a compression ratio of 20 and uses air as the working fluid. The state of air at the beginning of the compression process is \(95 \mathrm{kPa}\) and \(20^{\circ} \mathrm{C}\). If the maximum temperature in the cycle is not to exceed \(2200 \mathrm{K}\) determine \((a)\) the thermal efficiency and \((b)\) the mean effective pressure. Assume constant specific heats for air at room temperature.
Problem 57
A four-cylinder two-stroke 2.4 -L diesel engine that operates on an ideal Diesel cycle has a compression ratio of 22 and a cutoff ratio of \(1.8 .\) Air is at \(70^{\circ} \mathrm{C}\) and \(97 \mathrm{kPa}\) at the beginning of the compression process. Using the cold-airstandard assumptions, determine how much power the engine will deliver at \(3500 \mathrm{rpm}\)
Problem 59
An ideal dual cycle has a compression ratio of 15 and a cutoff ratio of \(1.4 .\) The pressure ratio during constantvolume heat addition process is \(1.1 .\) The state of the air at the beginning of the compression is \(P_{1}=14.2\) psia and \(T_{1}=75^{\circ} \mathrm{F}\) Calculate the cycle's net specific work, specific heat addition, and thermal efficiency. Use constant specific heats at room temperature.
