How Dual Fuel (DF) Can Help to Decarbonize Certain Off-Road Application

The target in decarbonization of vehicles in Offroad sector will become more and more stringent due to future cities restriction regarding the CO₂ emissions and to the different target defined from EU for decarbonization of different sectors. Certain Offroad vehicles such as mobile crane are operating in cities with crane mode, but also the vehicle can be driven in the motorway with the equipment. A certain flexibility of power train is required to cover both operation modes. One of the main challenges of hydrogen is the volumetric energy density of the fuel which has an impact on the size of the hydrogen tank. By replacing a certain amount of required energy using HVO (Hydrotreated Vegetable Oil, or diesel) as fuel, it will have a significant impact on the total power train volume.

The hydrogen dual fuel solution has a potential to offer a significant improvement in terms of CO₂ emission reduction in Tank-to-Wheel using Diesel or HVO as a pilot fuel. The dual fuel (DF) concept (hydrogen/diesel or HVO) represents a possible solution to decarbonize some Off-Road application. Additional advantage of DF is its potential to retrofit the current diesel engines by smart integration of hydrogen injectors in the intake manifold, while conventional injection of HVO (or Diesel) into the cylinder for ignition of the premixed mixture (air/fuel) is used.

The development of the technology has started by design and simulation which leads to combustion architecture definition. The experimental investigation of dual fuel operation has been performed on 4-cylinder engine (9 L). Several combustion layouts for hydrogen injection such as port fuel (PFI) and direct injection (DI) configuration has been considered in the analysis. The best configuration has been selected for testing of several OFF-Road cycles to evaluate the technology performance in terms of power density and emission in real vehicle operations. Afterward, an outlook regarding further application of the hydrogen dual fuel engine has been illustrated regarding the size of the complete power train (Fuel tanks, engine, cooling unit, etc.…) in different control of energy management configuration. At the end, a complete technology evaluation with several integration studies of the power train have been conducted and analyzed for different vehicle types.