1. What is Injector Duty Cycle?

The injector duty cycle represents the percentage of time the fuel injector is open during one complete engine cycle. It's a critical parameter for fuel system tuning and ensuring injectors aren't overworked.

2. How Does the Calculator Work?

The calculator uses the duty cycle equation:

Where:

• \( Pulse\ Width \) — Injector pulse width in milliseconds (ms)
• \( RPM \) — Engine speed in revolutions per minute
• 12000 — Conversion factor (ms to minutes and 2 revolutions per cycle)

Explanation: The equation calculates what percentage of time the injector is open during each engine cycle, accounting for engine speed and injection duration.

3. Importance of Duty Cycle Calculation

Details: Monitoring injector duty cycle helps prevent injector overuse (typically kept below 80-85% for safety margin), ensures proper fuel delivery, and aids in fuel system upgrades.

4. Using the Calculator

Tips: Enter pulse width in milliseconds (from ECU logs or tuning software) and current engine RPM. Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is a safe maximum duty cycle?
A: Most tuners recommend keeping duty cycles below 80-85% to allow for variations in fuel demand and prevent injector over-saturation.

Q2: How does duty cycle affect fuel delivery?
A: As duty cycle approaches 100%, injectors may not close completely between pulses, leading to erratic fuel delivery and potential engine damage.

Q3: Why does the calculation include RPM?
A: Higher RPM means less time available per cycle for injection, so the same pulse width results in higher duty cycle at higher RPM.

Q4: What if my duty cycle is too high?
A: Consider larger injectors, higher fuel pressure (if applicable), or reducing fuel demand through tuning or engine modifications.

Q5: Does this calculation work for all engine types?
A: This is for standard 4-stroke engines. Two-stroke engines would use a different divisor since they fire every revolution.