Fuel Pump Flow Rate Calculator

Fuel Pump Flow Rate Formula:

\[ \text{Flow Rate (GPH)} = \frac{\text{BSFC} \times \text{HP}}{\text{Density}} \]

Required Fuel Flow Rate:

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1. What is Fuel Pump Flow Rate?

The fuel pump flow rate is the volume of fuel (in gallons per hour) that a fuel pump needs to deliver to properly support an engine's power requirements. It's calculated based on the engine's horsepower, fuel efficiency (BSFC), and fuel density.

2. How Does the Calculator Work?

The calculator uses the fuel flow rate equation:

\[ \text{Flow Rate (GPH)} = \frac{\text{BSFC} \times \text{HP}}{\text{Density}} \]

Where:

\( BSFC \) — Brake Specific Fuel Consumption (lb/HP-h)
\( HP \) — Engine horsepower
\( Density \) — Fuel density (lb/gal)

Explanation: The equation calculates how much fuel volume needs to be delivered per hour to support the engine's power output, accounting for the engine's efficiency and fuel characteristics.

3. Importance of Proper Fuel Flow

Details: Proper fuel flow is critical for engine performance. Insufficient flow can cause lean conditions and engine damage, while excessive flow can overload the fuel system and reduce efficiency.

4. Using the Calculator

Tips:

BSFC typically ranges from 0.4-0.6 lb/HP-h for gasoline engines (0.5 is a good average)
Gasoline density is approximately 6.2 lb/gal
Diesel density is approximately 7.1 lb/gal
Enter your engine's maximum horsepower

5. Frequently Asked Questions (FAQ)

Q1: What is a typical BSFC value?
A: For gasoline engines, 0.45-0.50 is common for naturally aspirated engines, 0.55-0.60 for forced induction. Diesel engines typically have lower BSFC (0.35-0.45).

Q2: Should I add a safety margin to the calculated flow rate?
A: Yes, it's recommended to add 20-30% to the calculated value to ensure adequate fuel supply under all conditions.

Q3: How does fuel pressure affect flow rate?
A: Pump flow ratings are typically given at specific pressures. Higher pressure reduces actual flow, so check pump flow curves at your operating pressure.

Q4: What if I'm running ethanol blends?
A: E85 has lower energy content (higher BSFC, ~0.7-0.8) and different density (6.5 lb/gal). Adjust your inputs accordingly.

Q5: How do I convert GPH to LPH?
A: Multiply GPH by 3.785 to get liters per hour (LPH).