THERMAL ENGINEERING KTU MODULE 4 IMPORTANT QUESTIONS DISCUSSION - 2019 SCHEME S5

Introduction

This tutorial provides a comprehensive overview of important questions and concepts related to thermal engineering, specifically focusing on the combustion processes in internal combustion (IC) engines. It is particularly relevant for students following the KTU 2019 scheme in their mechanical engineering studies. We will cover essential topics such as combustion types, pressure crank angle diagrams, combustion chambers, and pollutants associated with IC engines.

Step 1: Understand the Basics of Combustion

• Familiarize yourself with the two main types of internal combustion engines:
  • Spark Ignition (SI) Engines: Utilize a spark plug to ignite the fuel-air mixture.
  • Compression Ignition (CI) Engines: Rely on the heat generated by compressing air to ignite the fuel.
• Study the combustion process in both engine types:
  • SI engines typically run on petrol.
  • CI engines typically run on diesel.

Step 2: Explore Pressure Crank Angle Diagrams

• Learn how to draw and interpret pressure crank angle diagrams. These diagrams graphically represent the pressure in the combustion chamber relative to the crank angle during one complete engine cycle.
• Key points to include:
  • Identify the pressure peaks that correspond to the ignition and combustion phases.
  • Understand how these diagrams help in analyzing engine performance and efficiency.

Step 3: Analyze Combustion Chambers

• Investigate different designs of combustion chambers in SI and CI engines:
  • SI Engine Combustion Chambers: Generally have a more complex design to promote better fuel-air mixing.
  • CI Engine Combustion Chambers: Designed to withstand higher pressures and temperatures.
• Understand the impact of chamber design on combustion efficiency and emissions.

Step 4: Identify Pollutants Emitted from IC Engines

• Recognize the common pollutants produced by internal combustion engines:
  • Carbon Monoxide (CO): Produced due to incomplete combustion.
  • Nitrogen Oxides (NOx): Formed under high-temperature conditions.
  • Hydrocarbons (HC): Result from unburned fuel.
• Discuss strategies to reduce these emissions in engine design and operation.

Step 5: Review Important Questions for Exam Preparation

• Compile a list of important questions related to the above topics that may appear in exams:
  • Explain the differences between SI and CI engines.
  • How does the pressure crank angle diagram reflect engine performance?
  • What are the advantages and disadvantages of different combustion chamber designs?
  • Discuss methods to minimize pollutants from IC engines.

Conclusion

In this tutorial, we have covered crucial aspects of thermal engineering relevant to internal combustion engines. By understanding combustion processes, pressure crank angle diagrams, combustion chamber designs, and pollutant emissions, you will be better prepared for exams and practical applications in mechanical engineering. For further study, consider diving deeper into engine design and emission control technologies.