Transitioning to zero-carbon fuels is pivotal for expediting the reduction of carbon emissions. Hydrogen demonstrates significant adaptability and emerges as a principal zero-carbon alternative fuel for fossil fuel internal combustion engine (ICE) platforms. Implementing hydrogen in both spark ignition (SI) and compression ignition (CI) engines has proven to be both economically viable and timely.
In this study, a conventional diesel engine was operated with pure hydrogen with minimal modification to engine hardware. It features a proactive, automated shutdown system to mitigate intake backfire risks associated with hydrogen port fuel injection (PFI) systems. A comprehensive engine characterisation was conducted using a lambda sweep test, measuring values from 1.5 to 4.5 with an integrated in-cylinder pressure transducer for high-resolution data. The study used an advanced Bandpass, Rectify, Integrate, Compare (BRIC) knock detection method for engine health monitoring and assessed stability through various metrics over 300 cycles. The performance and emission characteristics of a 100% hydrogen engine were analysed. Additionally, other low-carbon fuels, including methane and hythane (a blend of gaseous fuel with 80 % methane and 20% hydrogen by volume), were used for engine experiments to compare their performance with hydrogen.
The results indicate that hydrogen can function effectively in a diesel light-duty engine utilising a port-fuel injection and spark ignition system, achieving an indicated thermal efficiency of approximately 40%. The engine operates with exceptional stability, reflected in a Coefficient of Variation of Indicated Mean Effective Pressure (COVIMEP) of less than 1.6% at a maximum lambda of 4.2. Additionally, it maintains a high combustion efficiency of 97.4%, with minimal hydrogen slip observed in the exhaust. The hydrogen fuel demonstrates nearly zero carbon emissions, with NOx levels recorded below 50 ppm at lambda 2.5 and approaching zero NOx at lambda 3. Compared to methane and hythane, hydrogen can achieve better emission characteristics with near zero NOx and unburnt hydrocarbon. However, the power output of pure hydrogen operation is lower than that of methane and hythane, as a result of leaner operating conditions.