Volvo, one of the project partners, has tested DME and named it ‘the preferred fuel’ among the green fuels available.

The project taking place in Sweden, usess the entire technology chain: from the paper mill supplying black liquor via gas stations for fuelling DME to trucks actually running on DME.

Here are the soundbites from Haldor Topsøe’s Vice President Claus Hviid Christensen.

DME is a gas but it is transformed into liquid form at a pressure of just 5 bar. It is straightforward to handle in a process similar to that required for liquefied petroleum gas (LPG). The most common application today is as a propellant in spray cans. DME can be produced from natural gas and also from various types of biomass, in which case it is known as Bio-DME.

Bio-DME has both high energy efficiency and low greenhouse gas emissions all the way from the source to the wheel. The raw material used is black liquor, an energy-rich, highly viscous by-product of the pulp industry. With Bio-DME instead of diesel as a fuel, carbon dioxide emissions are cut by 95 percent.

Vehicle: Volvo DME truck

Tanks: DME is filled as a liquid via a special nozzle and stored in liquid form in the tanks.

Pump: a special fuel pump regulates the pressure in the common rail injection system.

Injectors: special DME injectors have been jointly developed by Volvo and Delphi.

Engine: the moving parts are identical to those in the diesel variant.

Engine management: the software has been modified to suit the different energy content.

Bio-DME – future potential

From an EU perspective, Bio-DME has the potential for replacing just over 50%* of today’s diesel oil in heavy road transport by 2030. The biggest challenge lies in creating an infrastructure for distribution of the fuel.

Fuel company Preem will build filling stations so the trucks can be used in regular regional and local operations. The first field-test truck is being unveiled today in Piteå, where the production of Bio-DME will take place.

Same performance, minimal emissions

Volvo’s DME truck uses a regular D13 engine which, after some modifications to the tank system, injection system and engine management software, functions perfectly together with the biofuel.

“Behind the wheel, it’s business as usual. Performance and driving properties are exactly the same as in the diesel variant. The difference and the major benefit with Bio-DME lies in its low carbon dioxide emissions,” says Mats Franzén, Product Manager Engines at Volvo Trucks.

An ideal fuel for diesel engines

Compared with a conventional engine, Bio-DME as a fuel in a diesel engine provides the same high efficiency rating along with a lower noise level. The combustion process produces very low emissions of particulates and nitrogen oxides. Therefore, a simpler system can be used for after-treatment of the exhaust gases. The engine can also provide higher torque at start-up and thus improve driveability. All told, this makes Bio-DME an ideal fuel for diesel engines.

Modifications to the fuel system

DME is filled in liquid form and stored in pressurised tanks in a leak-proof system. The pressure keeps the fuel in liquid form all the way to injection. Common rail technology is used to create the optimum high injection pressure. The lower energy content of DME, just over half that of diesel oil, is compensated by fitting larger tanks.

“We are noting immense interest in alternative fuels among our customers and we feel that Bio-DME offers considerable potential. The field test will last three years and the subsequent evaluation will determine whether the project will lead to full-scale industrial production,” says Claes Nilsson, President Volvo Trucks Europe Division.

Here is the video clip from Volvo on the topic.