1. What is Indicated Thermal Efficiency?

Indicated Thermal Efficiency is given by the ratio of indicated power generated by the engine to the power generated by the combustion of the fuel. It represents how effectively an engine converts the thermal energy from fuel into useful mechanical work.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Relative Efficiency (ηr) - The Relative Efficiency of an I.C. engine is the ratio of indicated thermal efficiency to the thermal efficiency of a theoretically reversible cycle.
• Air Standard Efficiency (ηa) - Air Standard Efficiency (in %) is the efficiency of the engine using air as the working medium. This efficiency is often called ideal efficiency.

Explanation: This formula calculates the actual thermal efficiency of an engine based on its relative performance compared to an ideal cycle and the theoretical maximum efficiency achievable.

3. Importance of Indicated Thermal Efficiency

Details: Indicated thermal efficiency is a crucial parameter for evaluating engine performance and fuel economy. It helps engineers optimize engine design, improve fuel efficiency, and reduce emissions in internal combustion engines.

4. Using the Calculator

Tips: Enter both Relative Efficiency and Air Standard Efficiency as percentage values. Both values must be non-negative numbers. The calculator will compute the indicated thermal efficiency as a percentage.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between indicated thermal efficiency and brake thermal efficiency?
A: Indicated thermal efficiency considers the power developed in the cylinder, while brake thermal efficiency considers the power available at the output shaft (accounting for mechanical losses).

Q2: What are typical values for indicated thermal efficiency?
A: For modern internal combustion engines, indicated thermal efficiency typically ranges from 30% to 45%, depending on engine type and operating conditions.

Q3: How does this relate to overall engine efficiency?
A: Indicated thermal efficiency represents the thermodynamic efficiency of the combustion process, while overall efficiency also considers mechanical and other losses.

Q4: What factors affect indicated thermal efficiency?
A: Compression ratio, air-fuel ratio, combustion chamber design, ignition timing, and engine speed all significantly impact indicated thermal efficiency.

Q5: Why is air standard efficiency considered ideal?
A: Air standard efficiency represents the maximum theoretical efficiency achievable in an ideal cycle without considering real-world losses like heat transfer, friction, and incomplete combustion.