{"id":13225,"date":"2020-06-08T14:11:02","date_gmt":"2020-06-08T19:11:02","guid":{"rendered":"https:\/\/blog.wika.com\/us\/\/?p=13225"},"modified":"2023-08-23T01:32:19","modified_gmt":"2023-08-23T06:32:19","slug":"wika-develops-pressure-sensor-for-hydrogen-powered-vehicles","status":"publish","type":"post","link":"https:\/\/blog.wika.com\/us\/applications\/wika-develops-pressure-sensor-for-hydrogen-powered-vehicles\/","title":{"rendered":"WIKA Develops Pressure Sensor for Hydrogen-Powered Vehicles"},"content":{"rendered":"

In hydrogen-powered vehicles, the gas in the H2\u00a0<\/sub>storage tank has to be regulated through a series of control valves before reaching the fuel cell. Pressure instruments play an important role in this process, but standard pressure sensors fall short in hydrogen applications because they lack suitable sensor materials. WIKA\u2019s MH-3-HY is specifically designed for vehicles that use hydrogen fuel cells. What\u2019s more, it has EC79\/2009 approval.
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\nManufacturers of off-road machinery, trucks, and buses are increasingly interested in hydrogen as a fuel source. Why? Customers\u2019 demand for greater safety, environmentalism, performance, and efficiency. Hydrogen-powered vehicles are much cleaner than those with internal combustion engines, as the only byproduct of mixing hydrogen and oxygen is water vapor. Zero emissions is especially a concern for vehicles used indoors \u2013 <\/span>forklifts, scissor lifts, tow tractors, order pickers, and transportation vehicles \u2013 as combustion engines release dangerous carbon monoxide, volatile organic compounds (VOCs), and other harmful byproducts into the air, even when vehicles contain the latest in pollution control equipment. <\/span><\/p>\n

Battery-powered electric vehicles are clean, but the main drawback is their limited range and, thus, the need for frequent recharging. What\u2019s more, each charging cycle can take several hours, which means these machines are sitting idle instead of producing work, reducing the company\u2019s ROI for these assets. Hydrogen-powered vehicles, on the other hand, take only a few minutes to refuel, and are back into operation immediately. Fuel cells are also lighter than traditional batteries, an advantage when weight is an important consideration. Countries in East Asia (especially Japan) and Western Europe are frontrunners when it comes to hydrogen fuel cell vehicles, but others are catching up.<\/p>\n

Hydrogen Applications Require Special Pressure Sensors<\/span><\/h2>\n

The compressed gas in hydrogen fuel tanks is under high pressure: around 5,250 psi for most off-road machinery and municipal vehicles. Before the hydrogen reaches the fuel cell to be converted into energy, its stored pressure has to be reduced to the fuel cell working pressure. For greater control and safety, this process usually takes two steps:<\/p>\n

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  1. A high-pressure reducing valve located near the tank lowers the pressure to just under 300 psi before entering the system.<\/li>\n
  2. A pressure regulator then further reduces the pressure to approximately 15 psi before entering the fuel cell injector.<\/li>\n<\/ol>\n

    The high-pressure reducing valve typically uses two pressure sensors: one at the valve inlet and another at its outlet to ensure that system pressure is within safe limits. If the system pressure is not regulated correctly, a pressure relief valve will sense an over-pressure condition and vent the hydrogen to the atmosphere. If the system pressure becomes too low, the fuel cell won\u2019t have enough pressure for operation and will eventually shut down the machine.<\/p>\n

    As with any pressure sensor, it has to be accurate and robust enough for a particular application. However, H2\u00a0<\/sub>applications pose challenges to these requirements because the molecule breaks down into two hydrogen ions. These atoms can easily enter the crystal structure of many common metals, including stainless steel, and the diffusion process accelerates at higher temperatures and pressures. This is called hydrogen permeation, and it does two things in a pressure sensor:<\/p>\n