Diesel engines can be converted to run on 90% hydrogen

The authors of this development say that the CO2 emissions were reduced by more than 85% compared to a regular unmodified diesel engine. Furthermore, hydrogen fuel recently became less expensive than diesel, which could mean that hybrid diesel-hydrogen engines could appear on the mass market, too.

“We have shown that we can take those existing diesel engines and convert them into cleaner engines that burn hydrogen fuel,” said Prof. Kook, one of the authors of the paper describing the results of this engineering study.

In order to make diesel engines run on hydrogen, the original fuel injection system remains in place. However, it is necessary to install an additional injector for hydrogen to deliver it directly into the cylinder.

The direct hydrogen injection must have the proper timing to achieve the best fuel mixture burning conditions, while also minimizing the residual emissions of toxic nitrogen oxide typical to all diesel engines.

Scientists say that they managed to reduce nitrogen oxide emissions below the levels of a regular diesel engine. The efficiency gains were also significant: in the diesel-hydrogen hybrid, the fuel efficiency was improved by more than 26%.