A gasoline engine has a compression ratio of 8.00 and uses a gas for which y = 1.40. (a) What is the efficiency of the engine if it operates in an idealized Otto cycle? % MY NOTES %% ASK YOUR TEACHER (b) If the actual efficiency is 18.0%, what fraction of the fuel is wasted as a result of friction and energy losses by heat that could by avoided in a reversible engine? (Assume complete combustion of the air-fuel mixture.)

A gasoline engine has a compression ratio of 8.00 and uses a gas for which y = 1.40. (a) What is the efficiency of the engine if it operates in an idealized Otto cycle? % MY NOTES %% ASK YOUR TEACHER (b) If the actual efficiency is 18.0%, what fraction of the fuel is wasted as a result of friction and energy losses by heat that could by avoided in a reversible engine? (Assume complete combustion of the air-fuel mixture.)

College Physics

1st Edition

ISBN:9781938168000

Author:Paul Peter Urone, Roger Hinrichs

Publisher:Paul Peter Urone, Roger Hinrichs

Chapter15: Thermodynamics

Section: Chapter Questions

Problem 28PE: A certain gasoline engine has an efficiency of 30.0%. What would the hot reservoir temperature be...

See similar textbooks

Similar questions

An idealized diesel engine operates in a cycle known as the air-standard diesel cycle shown in Figure P18.48. Fuel is sprayed into the cylinder at the point of maximum compression, B. Combustion occurs during the expansion B C, which is modeled as an isobaric process. Show that the efficiency of an engine operating in this idealized diesel cycle is e=11(TDTATCTB) Figure P18.48.
A 65-g ice cube is initially at 0.0C. (a) Find the change in entropy of the cube after it melts completely at 0.0C. (b) What is the change in entropy of the environment in this process? Hint: The latent heat of fusion for water is 3.33 105 J/kg.
A Carnot engine operates in a Carnot cycle between a heat source at 550 and a heat sink at 20 . Find the efficiency of the Carnot engine.
At point A in a Carnot cycle, 2.34 mol of a monatomic ideal gas has a pressure of 1 4000 kPa, a volume of 10.0 L, and a temperature of 720 K. The gas expands isothermally to point B and then expands adiabatically to point C, where its volume is 24.0 L. An isothermal compression brings it to point D, where its volume is 15.0 L. An adiabatic process returns the gas to point A. (a) Determine all the unknown pressures, volumes, and temperatures as you f ill in the following table: (b) Find the energy added by heat, the work done by the engine, and the change in internal energy for each of the steps A B, B C, C D, and D A (c) Calculate the efficiency Wnet/|Qk|. (d) Show that the efficiency is equal to 1 - TC/TA, the Carnot efficiency.
Which of the following is true for the entropy change of a system that undergoes a reversible, adiabatic process? (a) S 0 (b) S = 0 (c) S 0
An athlete whose mass is 70.0 kg drinks 16.0 ounces (454 g) of refrigerated water. The water is at a temperature of 35.0F. (a) Ignoring the temperature change of the body that results from the water intake (so that the body is regarded as a reservoir always at 98.6F), find the entropy increase of the entire system. (b) What If? Assume the entire body is cooled by the drink and the average specific heat of a person is equal to the specific heat of liquid water. Ignoring any other energy transfers by heat and any metabolic energy release, find the athletes temperature after she drinks the cold water given an initial body temperature of 98.6F. (c) Under these assumptions, what is the entropy increase of the entire system? (d) State how this result compares with the one you obtained in part (a).