In the world of internal combustion engines, there are many different fuel types that are less well known. While gasoline and diesel fuel are the main runners in the internal combustion engine technology, using hydrogen as a fuel is also very popular due to its green and renewable nature. Hydrogen fueled vehicles have been around for a long time and the technology to use hydrogen fuel in an internal combustion engine is very similar to that for other fuels. As the world transitions away from fossil fuels such as gasoline and diesel fuel, hydrogen fueled vehicles are likely to become more and more common. One of the main benefits of a hydrogen fueled vehicle is that the fuel itself does not produce many greenhouse gases during combustion, and unlike electric vehicles, hydrogen vehicles have the ability to refuel without the aid of an electric grid. This makes them particularly useful for areas of the world that will not be electrified. Unfortunately, the burning of hydrogen fuel poses some unique challenges. When introduced into a typical internal combustion engine combustion chamber, such as that on a diesel engine, hydrogen fuel will pre-ignite. This pre-ignition can be detrimental to the engine and can cause catastrophic failure. Two companies that are pioneering the hydrogen fuel technology, Mahle and Liebherr, have developed a special apparatus that can be retrofitted into a diesel combustion engine to reduce the likelihood of pre-ignition in hydrogen powered vehicles. The apparatus is effectively a small combustion chamber that ignites the fuel before jetting the hot combustion gases into the main combustion chamber. This is accomplished using a series of nozzles to direct the combustion gases and ignite the secondary combustion chamber for engine power. A side-benefit of this technology is that thermal efficiencies increase, allowing the engine to produce higher compression. This technology is still in development, but is showing great promise for the future of hydrogen fueled vehicles.
-taken from www.sae.org