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The Thermal Efficiency Using Friction Power formula calculates the indicated thermal efficiency of an engine by accounting for friction losses. It relates brake thermal efficiency to the total power output including friction losses.
The calculator uses the formula:
Where:
Explanation: This formula accounts for the energy losses due to friction in the engine system, providing a more accurate measure of the engine's actual thermal efficiency.
Details: Accurate thermal efficiency calculation is crucial for evaluating engine performance, optimizing fuel consumption, and identifying areas for mechanical improvement in internal combustion engines.
Tips: Enter brake thermal efficiency (unitless), friction power in watts, and brake power of 4 stroke in watts. All values must be positive numbers with brake power greater than zero.
Q1: What is the difference between indicated and brake thermal efficiency?
A: Indicated thermal efficiency accounts for all energy produced during combustion, while brake thermal efficiency only considers the useful work output after accounting for friction losses.
Q2: Why is friction power important in efficiency calculations?
A: Friction power represents energy lost to mechanical resistance within the engine, which directly affects the net output power and overall efficiency.
Q3: What are typical values for thermal efficiency in engines?
A: Modern internal combustion engines typically achieve 25-40% brake thermal efficiency, while indicated thermal efficiency can be higher, accounting for friction losses.
Q4: How can friction power be measured?
A: Friction power is typically measured using motoring tests or calculated as the difference between indicated power and brake power.
Q5: Does this formula apply to both diesel and gasoline engines?
A: Yes, this formula applies to both diesel and gasoline 4-stroke engines, as it deals with fundamental thermodynamic principles common to both engine types.