Energy demand for transportation is increasing globally, driven by developing economies and expansion of urbanisation. Electrification of passenger cars is gradually becoming a reality, while hydrogen fuel cells (FCs) are also playing an increasingly important role. However, due to their limitations in energy density, this results to excess weight/volume for achieving mileage values similar to those of fuel-powered vehicles. Therefore, such powertrains are not suitable for heavy-duty, off-road and marine applications, as these applications require vehicles/vessels with adequate energy stored onboard and ability for high-power operation. Thus, the long-term decarbonisation strategy of these sectors has no alternative but utilisation of near zero CO2 emission (NZE) or carbon-free fuels. These so-called e-fuels are produced from renewable hydrogen (e-H2) reacting with CO2 in chemical processes leading to e-diesel, e-jet, e-gasoline, alcohols, di-methyl ether (DME) etc. Such e-fuels are utilized by the Dual-fuel internal combustion engines (DFICE), which represent the most promising Near Zero Emission alternative for these transportation sectors, satisfying the strictest emission legislations e.g. EURO VI or Tier IV standards, in Europe and in the US, respectively; moreover, they comply with the Tier III limit of the International Maritime Organization (IMO).
In order to allow the relevant industries to design efficient DFICE concepts, computational fluid dynamics (CFD) models have been long utilised. However, existing models fail to predict processes where a variety of fuel mixtures are injected and combust simultaneously. This is due to the simplifications made for the mixing, phase-change and combustion, which all are happening at physical scales typically not resolved by numerical models utilised for industrial design, due to the very long computational time required. The overall objective of the EDEM project was to develop models suitable for flow and chemistry processes taking place at the physically smallest scales realised in the relevant equipment and operating conditions. The developed so-called ‘sub-grid-scale’ models derived with the aid of these models, have been implemented in software utilised by engine and fuel injection equipment manufacturers in order to assist in the design of DFICEs. The EDEM project developed such CFD models and validated them against new experimental data.
DFICEs are relevant to the following, non- exhaustive, list of applications: power generation, cargo ships and tankers, light and heavy-duty trucks, tractors, earth-moving machines and haul trucks. By providing their research findings to the relevant industry and by disseminating their results to the scientific community the EDEM project contributes to the reduction of soot, which is one of the deadliest forms of pollution.
