Indicated Power Calculator

Indicated Power Formula:

\[ IHP = \frac{P \times L \times A \times N}{33000} \]

Mean Effective Pressure (P):

psi

Stroke Length (L):

Piston Area (A):

in²

Engine Speed (N):

RPM

Indicated Horsepower (IHP):

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1. What is Indicated Power?

Indicated Power (IHP) is the theoretical power developed in the cylinders of an engine, calculated from indicator diagram measurements. It represents the total power developed by combustion before accounting for mechanical losses.

2. How Does the Calculator Work?

The calculator uses the indicated power formula:

\[ IHP = \frac{P \times L \times A \times N}{33000} \]

Where:

\( P \) — Mean effective pressure (psi)
\( L \) — Stroke length (ft)
\( A \) — Piston area (in²)
\( N \) — Engine speed (RPM)
33000 — Conversion constant (ft-lb/min to horsepower)

Explanation: This formula calculates the power developed inside the engine cylinders based on pressure measurements, piston movement, and engine speed.

3. Importance of Indicated Power Calculation

Details: Calculating indicated power is essential for engine performance analysis, efficiency calculations, and comparing the theoretical power output of different engine designs before accounting for mechanical losses.

4. Using the Calculator

Tips: Enter mean effective pressure in psi, stroke length in feet, piston area in square inches, and engine speed in RPM. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between indicated power and brake power?
A: Indicated power is the theoretical power developed in cylinders, while brake power is the actual power available at the crankshaft after accounting for mechanical losses.

Q2: How is mean effective pressure determined?
A: Mean effective pressure is typically calculated from indicator diagrams that measure pressure variations throughout the engine cycle.

Q3: What is the significance of the constant 33000?
A: This constant converts the product of pressure, length, area, and RPM from ft-lb/min to horsepower (1 hp = 33000 ft-lb/min).

Q4: Can this formula be used for all engine types?
A: This formula is primarily used for reciprocating piston engines. Different formulas may be needed for other engine types like turbines or rotary engines.

Q5: How does indicated power relate to engine efficiency?
A: Comparing indicated power to brake power allows calculation of mechanical efficiency, which indicates how much power is lost to friction and other mechanical factors.