Fuel injection with hydrogen gas caught on film

Like electricity, hydrogen can be used to transport, store and provide energy, and has great potential as an energy carrier in a renewable energy system where it is produced from, for example, sun, wind or water.

Research into hydrogen as an energy carrier is yet still at a very early stage. At Chalmers, research into hydrogen has been going on for about two years, when the first test of an engine was done. Mats Andersson is associate professor at the Department of Mechanics and Maritime Sciences, has many years of experience in combustion research, and has been involved since the start of Chalmers' hydrogen research.

“We have had a nose for what has been going on, people here in the department have seen this thing with hydrogen coming,” he says. “We invested in it early on and have received support from the department to build up the hydrogen infrastructure in our lab.”

Built infrastructure

Together with his colleagues, he has carried out intensive work on building up infrastructure to be able to make so-called spray measurements of hydrogen.

“We have worked for well over a year to get this system of hydrogen gas started in the spray lab, and now we have got everything in place and made it work,” says Mats Andersson.

What they have managed to do is to use advanced optical measurements to capture fuel injection with hydrogen gas on film and see how the hydrogen gas spreads inside a chamber.

Working with hydrogen involves a number of different challenges. Hydrogen is extremely explosive and flammable, so safety around the experiments is rigorous. Hydrogen is also invisible, which of course makes it difficult when you, like the Chalmers researchers, work with optical measurements. In the experiments, the researchers therefore send parallel light into the pressurized instrument chamber where the hydrogen injection takes place.

100,000 pictures per second

“The parallel light is focused on a razor blade, and we film part of it with a video camera that takes 100,000 images per second. When hydrogen is injected, a mirage effect occurs, like when it's hot outside or when you stand behind an engine - it vibrates in the air,” says Mats Andersson.

In this way, the researchers can see how the hydrogen gas spreads in the instrument chamber.

With the help of the films, Mats Andersson and his colleagues hope to be able to answer a number of questions about hydrogen. It regards things like how the fuel is distributed inside the chamber, whether air is drawn into the hydrogen jet and how homogeneously it is mixed. Once they have that information, they can start calibrating the amount, and convert it into fuel concentrations – is the mixture combustible? Is there too much fuel? Too little? Does the fuel have time to mix properly?

Use a laser to ignite

“When we have learned more about what the injection looks like, we will also try to ignite it. In an engine, for example, you use spark plugs for that, but we use a laser that creates a spark. We can move that spark around in different places inside the chamber, and see where it ignites and how well it burns.”

Mats Andersson believes that today it is the interest in hydrogen that keeps the research on combustion engines going - when he is at conferences, the lectures are packed when it comes to hydrogen research - and that Chalmers is now on the starting line to start doing world-leading research in the field.

“What we do is to combine basic research and applied research, he says. "We have advanced optics and laser setups, equipment that has been built up over 20 years for our spray research and which we are now converting to look at hydrogen gas. And we have talented engineers who keep this going, because it's a massive project. We can also modify our equipment, such as nozzles and chambers, and get access to advanced hydrogen injectors using the contacts we have with the business community.”

He believes we will be able to see prototype vehicles powered by hydrogen on the road within a few years. After that, it remains to be seen when it will become commercial.

“It needs hydrogen production, distribution networks, and of course vehicles that can use it - it's something of a 'the chicken or the egg' situation. Our piece of the puzzle at Chalmers is to ensure that Swedish industry can provide competitive vehicles for these applications, and via our close corporate collaborations around hydrogen we contribute knowledge that goes straight into our partners' product development.”