Lorries will need hybrid engines to meet 2025 EU climate targets

Researchers from the Polytechnic University of Valencia (UPV) found that compared to diesel, the technology would see levels of NOx and soot decline by 92 per cent and 88 per cent respectively, plus CO2 emissions from the exhaust pipe by 15 per cent.

This would help haulage firms meet the EU’s truck regulations for 2025 which the UPV researchers called “demanding”.

“In five years, these lorries must emit 15 per cent less carbon dioxide,” said UPV professor Antonio García. “The figures we have obtained, both for carbon dioxide and some of the other most harmful contaminating agents from combustion engines, have been very positive.”

By using dual-fuel combustion and a hybrid structure, the benefits of both types can be maximised, the researchers said.

Electrical assistance prevents the use of the thermal engine in low-efficiency conditions whereas the thermal engine in the full system makes it possible to obtain “economically viable vehicles” compared to the purely electrical models, Garcia added.

Optimisation of the electrical components allows the thermal engine to work in its areas of highest performance, with 13 per cent less fuel consumption than a conventional diesel vehicle.

Computer simulations were used to model a conventional diesel mechanism system which was then optimised to take the different electrical components into account, such as the engine, generator and battery.

The researchers believe their simulation methodology makes it possible to significantly decrease the amount of experimental trials needed to be carried out and therefore the cost of developing the technology.

The cost of production was taken into account, including the price of the batteries and possible savings in terms of penalisation for an excess of CO2 emissions.

The current price of the batteries currently stands at around €176/kWh (£161/kWh) and this is estimated to fall to around €100/kWh by 2025. When the economic penalty enforced on lorry manufacturers if they do not respect the CO2 limit in 2025 is taken to account (€4,250 per g/tkm), the UPV solution should prove to be the most cost-effective, if the computer model is correct.

“Taking into account the current price of the batteries and the penalties proposed by the European Union for 2025, the dual-fuel technology for lorries between 18 and 25 tonnes has the best benefits when using small-capacity batteries (up to 10kWh),” said researcher Javier Monsalve.

“The use of packs of larger batteries would substantially increase the end cost of the vehicle. It is true that it would drop with the foreseeable fall in the price of the lithium-ion technology in coming years, but until then it will be hard to see purely electrical lorries manufactured in mass.”