Helium Leak Tester for Automotive Fuel System Leak Detection

Technical Specifications of Helium Leak Detector SFJ-231

Helium Leak Detection in Automotive Fuel System 

Helium mass spectrometer leak detectors are widely used in automotive fuel system leak detection due to their high sensitivity (up to 10⁻⁹ Pa·m³/s) and reliability. They are commonly used for leak detection in components such as fuel tanks, fuel lines, and evaporative emission systems.The following provides a detailed explanation of specific applications, leak detection methods, and procedures:

1. Vacuum Method (Negative Pressure Leak Detection)

Application Scenarios: Overall leak detection of sealed components such as fuel tanks and sealed pipelines.
Detection Steps:

• Vacuuming: Evacuate the fuel system to 10⁻² to 10⁻³ Pa (requires a vacuum pump system).
• Helium Blowing: Spray helium gas (pressure 0.1 to 0.2 MPa) around the test area (e.g., welds, joints).
• Detection Signal: Helium entering the system through leaks is captured by a mass spectrometer and triggers an alarm.
• Leak Point Localization: The leak point location is determined by moving the spray gun or segmentally isolating the system.

2. Pressurization Method (Positive Pressure Leak Detection)
Applicable scenarios: EVAP carbon canisters, fuel lines, and other pressure-resistant components.
Detection Steps:

• Helium mixture injection: Inject a mixture of 5%–10% helium and nitrogen into the component (pressure 0.3–0.5MPa).
• Seal and maintain pressure: After stabilizing the pressure, place the component in a vacuum chamber or connect it to the leak detector's suction gun.
• Detect leaks: Use a mass spectrometer to detect helium escaping from the leak.
• Advantages: Suitable for complex-shaped components, no need for overall vacuum extraction.

3. Sniffer Method (Local Scanning)
Application Scenarios: Online rapid leak detection of fuel systems that have been assembled (e.g., engine compartment piping).
Detection Steps:

• Internal Helium Filling: Fill the fuel system with helium (working pressure).
• External Scanning: Move the suction gun along weld seams, O-rings, and other areas (distance 1–3 mm).
• Real-Time Feedback: The mass spectrometer peak corresponds to the leak location