Liebherr H964 is a very compact 9 liters 4-cylinder hydrogen engine. Still in development, this engine presents promising and encouraging results in terms of CO2 and nitrogen oxides (NOx) emissions. This 4-cylinder engine comes with direct injection technology (DI). Within this technology, the hydrogen is injected directly into the combustion chamber. Hydrogen direct injection is particularly well suited for applications with high demands on dynamics and power density within a limited installation space.