GAC Hydrogen Engine: Fire and Water from China

The car company builds combustion engines, electric cars and has presented a fuel cell car. Now the Chinese have also developed a hydrogen internal combustion engine.

The Guangzhou Automobile Group (GAC) has been building a number of combustion models under the GAC Trumpchi brand name since 2010. In 2017, the company founded GAC New Energy Automobile, which has been producing electric cars under the Aion brand name since 2019 and claims to be the fastest growing electric car manufacturer in the world. In 2019, the brand is said to have sold a good 33,000 cars. The program includes the Aion S sedan, the Aion LX crossover was added in October 2019, and the Aion V has been available since June 2020. In August 2020, GAC introduced the Aion LX Fuel Cell fuel cell powered car.

But the Chinese not only want to use the hydrogen to generate electricity in a fuel cell in the vehicle, but also use it as a fuel in hydrogen combustion engines. For this purpose, a reciprocating piston engine was developed on the basis of its own fourth engine generation, which burns green hydrogen and is therefore intended to be climate-neutral. The manufacturer emphasizes that they hold relevant patents for the new technology.,

Three-cylinder burns H2

GAC developed a new combustion chamber for the three-cylinder, which is supposed to mix hydrogen and air better. In addition, improvements to the hydrogen supply system should increase the power density and reduce the risk of leaks - hydrogen is very light and extremely volatile, so leaks are always an issue.,

The new engine should also be able to dissipate heat particularly well, which should minimize the risk of fire. Reinforced pistons, piston rings and connecting rods are designed to improve heat dissipation in both the cylinder head and cylinder block. According to GAC, it aims for thermal efficiency of more than 44 percent, which the manufacturer says would be a benchmark in China. The company Obrist from Austria promises 45 percent for their self-developed 2-cylinder; the generator, which only produces electricity for the electric motor and battery in the car, is said to run on methanol, which the Austrians also want to know is produced on the basis of green hydrogen. In the picture gallery we show the technology of hydrogen cars with fuel cells.,

It is not the motor efficiency that decides

In view of the manageable overall efficiency of hydrogen combustion engines (for e-fuels, which are also based on green hydrogen, it is around 16 percent ), the efficiency of the combustion engine as the last link in a long chain is of more academic importance.Because so much energy is required to produce hydrogen and when converting the gas back into electricity, considerable parts are lost again (significantly more during combustion, as outlined by GAC) and that causes the corresponding costs, not only describes VW boss Herbert Diess Hydrogen as the champagne of the energy transition .,

Accordingly, GAC also explains that the hydrogen engine is just one example of the many paths to a sustainable future. GAC not only wants to finish the development of the hydrogen engine, but also enter into cooperations to establish industrial chains for hydrogen production and storage - because one can fully use renewable energy sources such as wind and hydropower.,


The Chinese carmaker GAC practices openness to technology - but hydrogen as a fuel for cars is likely to be a dead end. Because just to use hydrogen in a fuel cell as output, four to five times the amount of electricity is required to operate an electric car (at least if you include transport from areas with effective green electricity generation). The efficiency of the hydrogen burner is even worse, and the required amount of CO2-neutral electricity is even greater.


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