How To Vent A Fuel Cell [Step By Step Guide]

Excess air in the fuel cells can affect the efficient performance of your vehicle. This means you should regularly release the air trapped in the fuel cell. If you're unsure how you can vent a fuel cell, we have done thorough research to find an answer. 

Venting a fuel cell requires the following steps:

  • Locate the vent faucet
  • Check the vent valve
  • Gently and slowly open the vent faucet
  • Vent the pressure in the fuel cell
  • Close up the vent faucet

Keep reading, as this article will explain the steps listed above. We would also answer some other questions related to venting fuel cells. 

How To Vent a Fuel Cell [Step-by-Step Guide]

Fuel Cell of Toyota Mirai

Venting a fuel cell refers to the process of releasing gases from the cell in a controlled manner. Fuel cells generate electricity, and as a reaction occurs, gases are produced.

These gases need to be released from the cell to maintain the proper balance of gases within the cell and to prevent the build-up of pressure that could cause the cell to malfunction or fail.

Fuel cells can be vented in several different ways, depending on the cell type and specific application. Some common venting methods include using a scrubber to remove contaminants from the gases or simply releasing the gases into the atmosphere.

Regardless of the method used, it is important to follow safety guidelines and regulations when venting fuel cells to ensure the safety of people and the environment.

Understanding the steps involved in venting a fuel cell would help you carry out the process safely. Here is the step-by-step guide to venting a fuel cell by releasing the gases. 

Step 1: Locate The Vent Valve

The fuel cell is typically located under the vehicle's hood and the rest of the powertrain components. The vent valve is commonly fitted on the top or side of the fuel cell for proper identification.

Step 2: Check the Vent Valve

A vent valve is a mechanical device designed to open and close in response to changes in pressure within the fuel cell. It allows gases to be released from the cell when the pressure reaches a certain level and prevents gas from being released when the pressure is within a normal operating range.

The specific pressure range and design of the vent valve will depend on the fuel cell type and the application's requirements. Some of these faucets are factory-fitted and come with a lockable handle to avoid the unintentional release of gas in the cell.

Step 3: Gently Open the Vent Faucet and Vent 

While opening the vent valve, always ensure you direct the hose away from any open ignition to prevent fire outbreaks. Release the excess air in the fuel cell until the cell is moderately relieved to take in filtered air.

Step 4 Close up the Vent Faucet

This is the final stage of venting the fuel cell. Lock up the vent valve upon completely releasing the unwanted pressure in the cell.

What Are The Six Types of Fuel Cells

Fuel Cell Future Hydrogen, How To Vent A Fuel Cell [Step By Step Guide]

Numerous fuel cells function based on the catalyst and fuel required, among other factors contributing to their operational efficiency. Below are six types of fuel cells you should know. 

Polymer Electrolyte Membrane Fuel Cells

Polymer Electrolyte Membrane [PEM] fuel cells use hydrogen, oxygen, and water to function. They are particularly well-suited for use in portable and automotive applications because they can operate at relatively low temperatures, have a quick start-up time, and are relatively lightweight.

PEM fuel cells have several advantages over other types of fuel cells. They are relatively efficient. They also have a fast response time, which makes them well-suited for use in vehicles that require quick acceleration.

Solid Oxide Fuel Cells

This is a sulfur-resistant fuel cell that uses biogas, gasses produced from coal, and natural gas to function. They are known for their high efficiency and durability, and they have the potential to be used in a wide range of applications, including stationary power generation, portable power, and transportation.

However, SOFCs also have some limitations. They are relatively expensive to manufacture, and they require a high-temperature operation.

Direct Methanol Fuel Cells

Unlike other fuel cells powered by hydrogen, the direct methanol fuel cell, as the name implies, is powered by methanol combined with water and directly flows to the fuel cell anode.

One of the main advantages of DMFCs is their high energy density, which makes them well-suited for use in portable and small-scale applications. 

DMFCs also have some limitations. They are relatively inefficient, with conversion efficiencies of around 30% or less. They also require a relatively pure methanol fuel source in order to function correctly, and they are sensitive to contaminants.

Alkaline Fuel Cells

While the PEM fuel cells use a combination of hydrogen, oxygen, and water, the alkaline fuel cells use an alkaline membrane.

Phosphoric Acid Fuel Cells

This is the first generation of sophisticated fuel cells, mainly used for stationary power generation. They have a relatively low power density, which limits their use in larger-scale applications. In addition, PACs are also expensive to manufacture and maintain.

Molten Carbonate Fuel Cells

These high-temperature fuel cells utilize electrolytes made of a molten carbonate salt combination. MCFCs are not well-suited for use in applications requiring quick response time, such as transportation.

Does a Fuel Cell Have To Be Vented?

A hydrogen fuel cell semi truck with H2 gas cylinder

Fuel cell venting allows filtered air to move into the vent valve and enhance cell efficiency. Many conditions can call for the venting of fuel cells, including having excess air in the cell and unnecessary loss of fuel.

These two conditions can drastically reduce the fuel quantity in your car and might dampen the functionality of the fuel cell. Thus, you must vent your fuel cell. 

What Causes Improper Fuel Cell Venting?

Improper tank vent size may cause poor fuel cell venting. You need a measuring tape to size a tank vent. First, measure the length and width in inches. Then, multiply them together and divide by 144 to get your gross free vent area. The following can also cause incorrect tank venting in your automobile:

  1. Blocked or bent connections
  2. Defective solenoid valves
  3. Obstructed venting valve 
  4. Corrosion 
  5. Blocked activated carbon canister
  6. Obstructed venting valve 

How Do You Test a Fuel Tank Vent? 

new car engine

A few different ways to test a fuel tank vent to ensure it is functioning correctly. One of the simplest ways to test a fuel tank vent is to inspect it visually. Check for any signs of damage or obstruction, such as cracks, dents, or debris blocking the vent. 

To test the flow rate of the fuel tank vent, you can also use a flow meter to measure the amount of gas that is being released through the vent. This can help you determine if the vent allows enough gas to be released to prevent a pressure build-up within the tank.

Another way to test a fuel tank vent is to perform a pressure test. This involves applying a slight amount of pressure to the fuel tank and checking to see if the vent allows the pressure to be released.

Here are the steps to test a fuel tank vent with a pressure tester. 

  1. Start by removing the fuel line from the carburetor.
  2. Then, connect the pressure vacuum tester to the end of the line.
  3. Pump pressure to 100 kpa [14psi].
  4. The line must not leak or bulge out within 30 seconds.
  5. If it does, it's faulty and must be replaced before continuing.

Check out this fuel pressure tester on Amazon. 

What is a Vent Solenoid? 

Solenoid valve of the transmission control valve

The vent solenoid plays an essential role in the system of a vehicle. It is the open valve with a sealing function for the EVAP system to stop air flowing into the charcoal canister. That is the opening and closing of vent values. 

Note that the vent solenoid can work automatically or manually, depending on the vehicle's system. It typically consists of a ferrous metal plunger and a wire wound coil. 


Fuel Cell Future Hydrogen

Venting a vehicle fuel cell is necessary to prevent the build-up of pressure. This process involves putting on protective equipment, identifying the venting valve in the fuel cell, and releasing excess and unnecessary pressure in the fuel cell. Thanks for reading. 

If you would like to learn more about fuel cells, check out these engaging articles: 

How to Cool Down a Fuel Pump

Do Chevrolet Trucks Have Flex Fuel? 

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