IC Engine Performance Lab Report Feedback A concise and well researched technical report is expected, do need to clearly state the aim and objectives of the lab, and have a proper structure. ie Introduction, Theory, Results, Discussion and Conclusions. Graphs and tables need to be meaningful for others to understand! Require titles, headings, proper units and legends; and use of secondary axis if appropriate. Don t use more decimal places than that you can justify their accuracy for! Separate tables for all original readings taken and calculated performance data with appropriate titles, labels and units. Scientific x-y scatter plots expected (shown to true scale; need looking more deeply into graphical representation of the processed results), individual data points should be marked; best fit trend line may be shown to demonstrate the effects of experimental errors; What s the purpose of the plotted graph? What you aim to communicate to the reader? Have you achieved that? You would need to describe, explain and discuss the results and graphs obtained, but don t just state the obvious :- State what your expectations are and any special features of the results. Identify the reasons for any discrepancies of the results and the possibility of effects of experimental errors, after all some experimental scatter are unavoidable! Particularly for instance, if care hasn t been made to the manual recording of the time taken for the fuel consumptions and engine not in a steady state; Tables and graphs should be referred to in the main body of texts. More critical in-depth discussions are desired. Use Appendix for detailed derivations and detailed procedural (specimen) calculations thus will not distract the logical flow of the main texts. The most important section is the student centered activities. Using the results obtained from your lab, and information gained from background readings, and other relevant resources to support the statements as evidence. Generally, you do seem to have a good understanding of the basic working principles on ICE performance and operation, but some of you did make unexpected mistakes in calculations of the results. The following are some of the key points : As demonstrated from the test results, both engines produced similar full load performance figures in terms of power outputs, thermal and mechanical efficiencies. There are some important differences! You need to understand why we may claim that diesel engines are quality governed while petrol engines are quantity governed . Petrol engines could be made lighter and perhaps more suitable to operate at relatively higher rev/mins than diesel engines (S/B ratio). However, the diesel engines would offer a better fuel economy and have better thermal efficiencies under a variety of load and speed conditions. Dual combustion cycle is the basic theoretical cycle for diesel engines, not the Diesel cycle. BMEP against Vpiston (or rpm) performance map could be produced. Factors Affecting Brake Mean Effective Pressure (engine s ability to do work and rating) is limited by pmax and Tmax permissible, and availability of air. (a). Air density at commencement of compression (b) The gas exchange process effectiveness, air trapping capability of the engine (c) The quality of combustion and fuel, thus combustion process and thermodynamic cycles Diesel engine has a flat torque characteristic, thus independent of its rotational speed (ie its ability to do work largely unaffected by rpm). Energy balance account could be made, roughly a third of the energy in fuel is lost to exhaust gases and the other third is lost to cooling water (including friction). Thermal efficiency and SFC are mirror images to each other, thus could be used for quantification of the fuel economy characteristics. Well researched answers with good quality references expected.