"We need to learn from the ground up how to build a reliable hydrogen engine"

At the LaSTS lab in the M-building at Johanneberg, research is in full swing on several potential alternatives to fossil fuels. The facilities include multiple engine test cells, a hybrid rig for electric and hybrid vehicles and fuel cells, as well as a laboratory for advanced optical diagnostics, where researchers analyze fuel sprays and gas jets.

Since the beginning of the year, Chalmers and Lund University of Technology have been working together with Horse Powertrain, Scania, SEM, and AB Volvo in a new joint project. As a first step, a gasoline engine provided by Horse Powertrain - one of Volvo Cars’ engine suppliers - has been rebuilt to run on hydrogen.

“The goal is to learn how to design and optimize engines for hydrogen operation. The project will run for three years, after which we will be able to assess whether we have succeeded in developing a better engine,” says Mats Andersson.

“The phase we are running now is our main contribution. The results we are generating will form the basis for calculations and experiments later in the project, where Chalmers will take the lead, with some support from us,” says Ayolt Helmantel, Technical Expert in Combustion Systems at Horse Powertrain.

One of the main tracks for the future

Hydrogen engines are not a new idea. The technology has been explored for decades, and some prototype vehicles were on the roads about 15 years ago, though without reaching wider adoption. In recent years, however, hydrogen has returned to the spotlight as a serious alternative to gasoline and diesel, with major investments planned at the European level, including the creation of a hydrogen infrastructure network.

For both academia and industry, research on hydrogen engines is akin to starting from scratch.

“The automotive industry needs to relearn how to design hydrogen engines with high efficiency and low emissions. Horse Powertrain doesn’t have its own hydrogen facilities, which is why they come to us at Chalmers to make use of our test labs,” says Mats Andersson.

Designing an efficient hydrogen engine presents many challenges. One of the most fundamental is gas–gas mixing: the hydrogen–air mixture must be very uniform, yet hydrogen displaces some of the air as it is injected into the cylinder. What’s more, the entire mixing process must take place within just a few hundredths of a second.

Many challenges to solve

“What we are focusing on now is what happens inside the combustion chamber. For example, we want to prevent pre-ignition, which is a major challenge since hydrogen burns quickly and ignites more easily than conventional fuels. If the mixture is uneven, it can also lead to high nitrogen oxide, NOx, emissions. We will run the engine under a variety of conditions – high load, low load, different speeds—to find optimal settings. Much of this work goes hand in hand with simulations carried out at Horse Powertrain, and we are learning a great deal from one another,” says Mats Andersson.

If researchers succeed in developing a robust hydrogen engine, the benefits could be significant. Carbon monoxide and soot emissions disappear, and the main by-product is simply water.

“From 2035, all new passenger cars must be free from fossil fuels, while fossil-fuelled trucks will gradually be phased out. By 2030, emissions must be 45 percent lower than in 2019, and by 2035, 65 percent lower. Since the regulations are based on tailpipe CO₂, hydrogen and electricity stand out as the fuels of the future,” says Mats Andersson.

"All available technologies must be put to use"

At the same time, he stresses that ten years is a long time, and much can change along the way. If you look back a decade, diesel was the dominant option. Today, enormous resources are being invested in alternative technologies, but no one knows for sure what the eventual mix will be between fuel cells, battery-electric vehicles, hydrogen, and biofuels.

"The outcome will likely differ around the world. But if we are to succeed in moving away from fossil fuels, all available technologies must be put to use,” says Mats Andersson.