Scientists reduce emissions of internal combustion engines by adding hydrogen to fossil fuels

Published: 18. 01. 2021

The air is an essential component of the environment: everything a person inhales is reflected in their health. Air pollution is considered to be one of the greatest environmental risks, is one of the top ten most common causes of premature death and is associated with a number of acute and chronic diseases and significant economic impacts.

Our scientists from the Vehicle Center of Sustainable Mobility of Faculty of Mechanical Engineering at the Czech Technical University in Prague have set themselves the goal of improving the efficiency of the internal combustion engine and reducing its emissions. We would like to achieve this with hydrogen added to conventional fossil fuels. Even petrol or diesel cars could come closer to meeting increasingly stringent emission limits in the future.

In Europe, emission limits are being tightened regularly and are becoming increasingly difficult to achieve for conventional petrol or diesel engines. One of the ways automakers can suit them is the development of hybrid engines or electric cars.

pracoviste/12921/projekty/12120/predkomurka/inst_fig2.jpgHowever, scientists from the Faculty of Mechanical Engineering are trying to offer another alternative. They want to improve the efficiency of combustion in a conventional internal combustion engine. This is done by adding a small amount of extremely flammable hydrogen to its work cycle.

We burn extremely lean mixtures and we are able to reduce pollutant emissions, including nitrogen oxide, and significantly reduce CO2 emission. However the use of extremely lean mixture calls for improvement of ignition procedure.

Instead of a conventional spark plug, a pre-chamber is inserted in the cylinder head, which is filled with a highly ignitable mixture and ignited by conventional spark in defined time. Jets of burning substance is penetrated the main combustion chamber and effectively ignite the extremely lean mixture. The phenomenon can be accented when hydrogen is used as a pre-chamber fuel.

pracoviste/12921/projekty/12120/predkomurka/CFD_teplota.jpgThe use of pure hydrogen as an engine fuel is under investigation. It was proven experimentally that extremely lean mixture of hydrogen with air can be exploited even with conventional ignition with high efficiency, extremely low emission of nitric oxide and close to zero emission of other pollutants. High boost pressure is demanded in order to reach sufficient engine power.    

Our scientists verify the new procedures experimentally on a test single cylinder engine. In the near future, optimizations of the parameters of the combustion system on a functional sample of experimental engine, built together with ŠKODA AUTO a.s. will follow.