1. What is a Compression Ratio Calculator?

Definition: This calculator determines an engine's compression ratio based on swept volume and clearance volume.

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

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( CR \) — Compression Ratio (unitless)
• \( Swept\ Volume \) — Volume displaced by piston (cc)
• \( Clearance\ Volume \) — Volume at top dead center (cc)

Explanation: The compression ratio compares the maximum to minimum cylinder volume during piston movement.

3. Importance of Compression Ratio

Details: Higher compression ratios generally improve efficiency but may require higher octane fuel. Lower ratios are more tolerant of lower quality fuels.

4. Using the Calculator

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

5. Frequently Asked Questions (FAQ)

Q1: What's a typical compression ratio?
A: Modern gasoline engines typically range from 8:1 to 12:1, while diesel engines often exceed 14:1.

Q2: How do I measure clearance volume?
A: Use a burette to measure liquid volume in the combustion chamber at top dead center.

Q3: Why does compression ratio matter?
A: It affects power output, fuel efficiency, and fuel requirements. Higher ratios generally improve thermal efficiency.

Q4: What happens if ratio is too high?
A: Excessive compression can cause knocking or pre-ignition, damaging the engine.

Q5: Can I change my engine's compression ratio?
A: Yes, through modifications like different pistons, head milling, or changing combustion chamber volume.