Comparison of Hydrogen Fuel Cell Power Systems and Hydrogen Internal Combustion Engines

    The basic principle of hydrogen fuel cells is to convert the chemical energy found in fuel into electrical energy through electrochemical reactions.The working principle of a hydrogen fuel cell involves hydrogen being broken down into electrons and hydrogen ions (protons) by a catalyst (platinum) in the fuel cell's anode. Protons pass through the Proton Exchange Membrane to the cathode, where they react with oxygen to form water and heat. The corresponding electrons flow from the anode to the cathode through an external circuit, generating electrical energy.The structure of hydrogen fuel cell stacks primarily consists of bipolar plates, membrane electrodes (proton exchange membrane coated with catalyst layer), gas diffusion layers, insulating plates, etc. Then, based on the stack, additional systems such as the air system, hydrogen system, electronic and electrical system, and water-thermal management system are integrated to form a hydrogen fuel cell power system, which is essentially a hydrogen fuel cell engine.

    Hydrogen internal combustion engines obtain power by burning hydrogen, and this type of engine, like conventional fuel engines, operates on four strokes: intake, compression, power, and exhaust, with hydrogen replacing conventional fuels.Taking the Cummins engine as an example, the structure of the hydrogen internal combustion engine is essentially similar to that of a natural gas engine, which includes components such as the cylinder block, crankshaft, cylinder head, ignition system, and mounting parts; parts of hydrogen internal combustion engines and diesel engines are also partly interchangeable, such as cylinder blocks, crankshafts, supports, flywheel housings, and other mounting components. The high degree of similarity and interchangeability of these components can utilize the economic advantages of Cummins hydrogen internal combustion engines, enhance equipment reliability, and provide crucial support in the industry's transition to low-carbon practices.

    The similarities between both require hydrogen and oxygen to participate in the reaction; All fuel storage units and hydrogen storage tanks are required; can power the vehicle. The difference is that the two generate energy in different ways, which also leads to a significant difference in efficiency, so fuel cell vehicles will have more mileage under the same hydrogen consumption; The way engines are built is also completely different; Fuel cells are more environmentally friendly than hydrogen combustion engines. In addition, there is no difference in the speed of energy release, and both internal combustion engines and fuel cells can achieve short-term high-power output.
    Compared with the two routes, the advantages of hydrogen fuel cells are high conversion efficiency, low pollution emissions, and high degree of commercial application, especially in terms of conversion efficiency, the thermal efficiency of hydrogen fuel engines is difficult to exceed 45%, while the conversion efficiency of hydrogen fuel cells can reach more than 60%.
    The advantages of hydrogen fuel engines are low cost (about 10% of fuel cells), low requirements for the purity of hydrogen, and the ability to be retrofitted with existing fuel engines. In addition, hydrogen internal combustion engines are more suitable for use in commercial vehicles such as medium- and heavy-duty trucks due to their higher output efficiency under high load conditions.