Materials you submit should be your own work.
Student: Zhou, Xiao
Fuel: 0.76 C8H18 + 0.11 C7H16 + 0.13 C2H5OH
Compression ratio: r = 11.1
In this project, you will examine the thermal efficiency of an Otto engine burning real
fuel. Your fuel is a three-fuel blend of
Name Chemical Formula
isooctane C8H18
n-heptane C7H16
ethanol C2H5OH
The numbers in your fuel specification above are mole fractions.
• Complete calculations for 110% theoretical air, representing a slightly lean fuel
mixture.
• Calculate the four-stroke engine power at 3000 RPM for an engine displacement
volume of 5.7 liters.
• For the inlet air conditions, use a temperature of 290 K and a pressure of 95 kPa.
• Calculate the thermal efficiency based on the calculated work, the fuel mass per
cycle, and the lower heating value of your fuel (which you must also calculate).
• Assume that the compression and expansion are isentropic.
• Account for the reactant and product mixtures to generate tables for these two
steps.
• Complete all calculations accounting for the variation in specific heats with temperature.
• Assume that the combustion takes place adiabatically and at constant volume.
Your results are to be presented in a detailed, typeset report, with the following contents,
whereby strict adherence to the due date and to the format of the report, as outlined
below, is expected:
• Title page
• Executive Summary (1 page)
• 1.0 Introduction – Statement of the problem
• 2.0 Thermodynamic analysis
– Written description of the calculations.
– A quantitative P-v diagram for the cycle.
MENG 346 – Energy Conversion Design Project B
– Present each state temperature (1–4), each state pressure, the balanced combustion
reaction, the power output, and the thermal efficiency in tabular form.
• 3.0 Conclusions
• Appendices (detailed calculations, explanations of programs/spreadsheets employed)
• Appendices should also include handwritten calculations for the reaction balancing
(stoichiometric and 110% theoretical air) and for the flame temperature calculation.
Reports without handwritten calculations will receive a grade of zero.
