Department of Mechanical Engineering
Bellville Campus
THERMODYNAMICS III LABORATORY
PETROL ENGINE
By
Student name
Student no
Signature
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Subject:
Lecturer:
APT260S
S Makhomo/S Pietrangeli
Evaluation Criteria
Introduction: (Aim for each lab, Background, List of the apparatus,
Procedure etc)
10%
50%
Result: (Calculations, Correct method, etc)
Explanations: (did you explain what you are doing rather than put
formulas.)
Discussion: (Discussion of the results, do they make sense? Any possible
errors, etc)
Conclusion and Recommendations: (Did we achieve our aims? What
do we need to do to improve our results)
Presentation, layout and neatness: (Cover page, Typed/ print neat,
report format, etc)
Total
10%
10%
10%
10%
100%
Date of submission:
I swear this is the original work of the author. All information obtained directly or indirectly
from other sources has being fully acknowledged.
TABLE OF CONTENTS
1. Aim of the Experiment
2. Theoretical Background
3. Experimental method, procedure and equipment
4. Data, findings and results
5. Discussion of experimental Results
6. Conclusions
7. References
8. Appendices
1.
AIM OF THE LABORATORY EXPERIMENT
To determine the basic characteristics of the Test Engine
To determine energy balance for the Test Engine and predict the losses
2.
THEORETICAL BACKGROUND
This section is to discuss the theoretical aspects leading to the experiment. Typically, this involves the
historical background of the theories published in the research literature and the questions or ambiguities
arose in these theoretical work. Citations for the sources of information should be given in one of the
standard bibliographic formats (for example, using square brackets with the corresponding number [2] that
points to the List of References). Explore this background to prepare the readers to read the main body of
the report. It should contain sufficient materials to enable the readers to understand why the set of data are
collected, and what are the salient features to observe in the graph, charts and tables presented in the later
sections.
Depending on the length and complexity of the report, the introduction and the theoretical background may
be combined into one introductory section.
3.
EXPERIMENTAL METHOD, PROCEDURE & EQUIPMENT
This section describes the approach and the equipment used to conduct the experiment. It explains the
function of each apparatus and how the configuration works to perform a particular measurement. Students
should not recopy the procedures of the experiment from the lab handout, but to summarize and explain the
methodology in a few paragraphs.
4.
4.1.1
DATA, FINDINDS & RESULTS
From the results, calculate the air mass flow rate, and plot the engine variables against speed. Then
for comparison, plot all variables on one chart or several charts of the similar scale. The engine variables
are:
• Air/fuel ratio
• Engine exhaust temperature
• Torque
• Power
• Specific fuel consumption
• Thermal efficiency
• Heat balance for test.
4.1.2
Look at the power and efficiency curves. What is the approximate optimum speed for the engine?
4.2.1
Create three tables similar to table 4(a).
4.2.2
From the tables, create a pie chart of the energy output values as percentages of the energy input.
What is noticeable about the losses at higher and lower speeds then the optimum performance speed?
4.2.3
5.
What could cause the “other losses”?
DISCUSSION OF EXPERIMENTAL RESULTS
The interpretation of the data gathered can be discussed in this section. Sample calculations may be included
to show the correlation between the theory and the measurement results. If there exists any discrepancy
between the theoretical and experimental results, an analysis or discussion should follow to explain the
possible sources of error.
6.
CONCLUSIONS
The conclusions section closes the report by providing a summary to the content in the report. It indicates
what is shown by the experimental work, what is its significance, and what are the advantages and limitations
of the information presented. The potential applications of the results and recommendations for future work
may be included.
APPENDICES
Table 1: Average fuel flow rate in ml/s
1.
2.
3.
4.
5.
6.
rev/ min
8ml
-
Average time
-
-
16ml
-
Average time
-
-
Use the average time for each of the volumes
Table 2: Engine variables at various engine speeds
1.
rev/ min
Ambient Temperature (°C)
Chamber Temperature (°C)
Differential Pressure (Pa)
Torque (N.m)
Cooling water flow rate (l/min)
Power (Mechanical) (kW)
T1 (Water inlet) (°C)
T2 (Water outlet) (°C)
T3 (Exhaust in) (°C)
T4 (Exhaust out) (°C)
2.
3.
4.
5.
6.
Table 3: Calculated engine variables at various speeds
1.
2.
3.
4.
5.
6.
rev/ min
Power (Brake)
Air/ Fuel ratio
Specific Fuel Consumption
Volumetric Efficiency
Thermal Efficiency
Table 4(a): Heat energy balance one @ low rpm (i.e,1500rpm), medium rpm (2500rpm) & high rpm
(3400rpm)
ENERGY INPUT (kJ/min)
ENERGY OUTPUT (kJ/min)
Heat of combustion
Mechanical Power =
mf × CV
Heat lost to exhaust =
Other losses =
Total
Total =
Table 5: Engine Technical details
Item
Specification
Ignition system
Flywheel Magneto
Absolute Maximum Power
8.7 kW (11hp) * at 3600 rev.min-1
Continuous Rated Power
9 kW (8hp) * at 3600 rev.min-1
Bore
88 mm
Stroke/ Crank Radius
64 mm/32 mm
Connecting Rod Length
105.5 mm
Engine Capacity
389 cm3 (0.389 L) or 389 cc
Compression Ratio
8,2: 1
Oil Type
Multigrade SAE 10 W – 30
Calorific value of petrol
43.8 MJ/kg
Typical value for density of petrol
0.74 kg/l
Oil Capacity
1.1 Litre
Orifice diameter
21 mm
Useful information
𝐀𝐢𝐫 𝑪𝒅 : 0.6
𝐄𝒙𝒉𝒂𝒖𝒔𝒕 𝑪𝑷 : 1 kJ/kg. K
%
𝐦𝐚𝐬𝐬 𝐟𝐥𝐨𝐰 𝐫𝐚𝐭𝐞 ∶ ṁa = Cd
πd2 2 PA ∆p
√
4
RTA