1. What is Engine Displacement?

Engine displacement is the total volume of all the cylinders in an internal combustion engine. It's typically measured in liters or cubic inches, but can also be expressed in gallons for certain applications.

2. How Does the Calculator Work?

The calculator uses the engine displacement formula:

Where:

• \( \pi \) — Pi (approximately 3.14159)
• \( \text{bore} \) — Diameter of each cylinder (inches)
• \( \text{stroke} \) — Length of piston travel (inches)
• \( \text{cylinders} \) — Number of cylinders in the engine
• 231 — Conversion factor (cubic inches per gallon)

Explanation: The formula calculates the volume of a single cylinder (πr²h) then multiplies by number of cylinders, and converts from cubic inches to gallons.

3. Importance of Displacement Calculation

Details: Engine displacement is a key specification that affects power output, torque, and fuel efficiency. It's used for engine classification, performance tuning, and regulatory purposes.

4. Using the Calculator

Tips: Enter bore diameter and stroke length in inches, and the number of cylinders. All values must be positive numbers (bore > 0, stroke > 0, cylinders ≥ 1).

5. Frequently Asked Questions (FAQ)

Q1: Why convert to gallons instead of using cubic inches?
A: Some applications (like marine engines or fuel system design) require displacement in gallons for practical measurements.

Q2: What's the 231 conversion factor?
A: There are exactly 231 cubic inches in one US liquid gallon, which is the standard conversion factor.

Q3: Does this work for all engine types?
A: This works for standard piston engines. Rotary engines (Wankel) and other designs require different calculations.

Q4: How accurate is this calculation?
A: It gives theoretical displacement. Actual displacement may vary slightly due to manufacturing tolerances.

Q5: Can I use this for two-stroke engines?
A: Yes, the displacement calculation is the same, though two-stroke engines effectively have different volumetric efficiency.