Global warming and the roadmap away from fossil fuels towards a CO2 neutral economy are driving innovations and technology developments. Currently heavy duty applications are typically powered by compression ignition (CI) engines and with fossil fuels such as heavy fuel oil (in the marine sector) and diesel (stationary applications). In a sustainable future alternative solutions will have to find their way in.

Renewable methanol is a very promising alternative fuel for these applications. Given its high octane number it is however primarily suited for spark ignition (SI) engines. To enable methanol in a marine environment, dual-fuel methanol-diesel (where a large portion of the diesel is replaced by methanol) is an important transitionary operating mode, as diesel operation remains possible when no methanol bunkering is possible. However in the long term methanol in SI operation offers the potential for increased efficiency and ultralow emissions.

For stationary applications there is no need for a transitionary phase and one can directly implement SI engines dedicated for methanol operation. To obtain these higher efficiencies, engine technologies (such as EGR, variable valve timing, etc) should be optimized for methanol’s physical properties. For example methanol’s high resistance to knock which enables high compression ratios (CR).

As current methanol SI engines typically start from SI gasoline engines, which have lower CR than CI diesel engines, it can be questioned whether starting from a diesel engine geometry would allow a better exploration of the high octane number property of methanol. This would enable to fully explore the knock resistive properties of methanol.