UNSW engineers retrofit diesel engine to run on hydrogen

A diesel engine has been modified by engineers at the University of New South Wales (UNSW) in Sydney to burn 90% hydrogen and 10% diesel fuel, reducing pollutants by 85%.

For heavy-duty applications, hydrogen is seen to be the sole viable option for lowering carbon emissions. The hydrogen combustion engine has not yet progressed beyond the prototype stage. Even the industry leader in engines, Cummins, with its fuel-agnostic engine architecture, was unable to solve all issue associated with making combustion engines use hydrogen.

Engineers from the UNSW have chosen an alternative strategy to reach the decarbonization objective. They experimented with adding hydrogen fuel to the diesel fuel rather than making the engine run entirely on hydrogen. They eventually reached a 90% hydrogen/10% diesel ratio, which appears to be the sweet spot for their new dual-fuel engine, after around 18 months of effort.

With the help of their hydrogen injection system, CO2 emissions are reduced to just 90 g/kWh, which is 86% less than what a typical diesel engine would emit. Not only that, but a dual-fuel engine has a 26% higher efficiency than a diesel engine.

The UNSW team inserted an additional hydrogen infusion straight into the cylinder while keeping the original diesel injection system to achieve this performance. The mixture condition inside the cylinder can be managed with careful timing of the hydrogen direct injection, which also reduces the engine’s damaging nitrogen oxide emissions.

This system’s lack of dependence on high-purity hydrogen, which is expensive to create, is another advantage. The research team is in discussions with potential investors regarding next stages and anticipates being able to market the novel system over the next 12 to 24 months.

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