1. What is a Compression Ratio Calculator?

Definition: This calculator computes the compression ratio of an engine based on swept volume and clearance volume.

Purpose: It helps automotive engineers, mechanics, and enthusiasts determine engine efficiency and performance characteristics.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( CR \) — Compression ratio (unitless)
• \( swept \) — Swept volume (cc)
• \( clearance \) — Clearance volume (cc)

Explanation: The total cylinder volume (swept + clearance) is divided by the clearance volume to determine how much the air-fuel mixture is compressed.

3. Importance of Compression Ratio

Details: Compression ratio affects engine efficiency, power output, fuel requirements, and thermal efficiency. Higher ratios typically mean more power but may require higher octane fuel.

4. Using the Calculator

Tips: Enter the swept volume (displacement per cylinder) and clearance volume (combustion chamber volume) in cubic centimeters (cc). Both values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is a typical compression ratio?
A: Gasoline engines usually range from 8:1 to 12:1, while diesel engines are typically 14:1 to 23:1.

Q2: How do I measure clearance volume?
A: It can be measured using a burette and plexiglass plate or calculated from known combustion chamber dimensions.

Q3: What happens if compression ratio is too high?
A: Excessive compression can cause engine knocking or detonation, potentially damaging the engine.

Q4: Does this account for head gasket thickness?
A: No, head gasket volume should be included in your clearance volume measurement.

Q5: How does compression ratio affect fuel economy?
A: Higher compression ratios generally improve thermal efficiency and fuel economy, up to the point where knocking occurs.