The COLHD Biopropane fuelled powertrain led by REPSOL
In the framework of the COLHD project, REPSOL is in charge of co-developing one of the three powertrains for HDVs, together with IDIADA, SIEMENS, Universitat Politècnica de València and University of Eastern Finland. SIEMENS will be in charge of modelling and simulating the fuel mixing and injection strategies. UPV will evaluate the combustion behaviour of different fuel mixtures under different operating conditions using a single cylinder engine. UEF is in charge of the development of a new after-treatment system to reduce engine emissions to the minimum and IDIADA will install, test and calibrate the final engine together with the new fuels mixing, injection and after-treatment systems developed.
One of the main innovations of this powertrain is the fact that the High-pressure engine will be designed and calibrated to be able to work with blends of different fuels, including diesel, HVO and Biopropane (or BioLPG). This represents an added challenge to the development, as the engine working conditions and performance may be highly different and will need to be adapted to different blends and fuel mixture calibration strategies, as well as to the use of renewable fuels – this has never been tested before. Biopropane is the future renewable fuel to be used in LPG (Liquified Petroleum Gas, more commonly known as Autogas), both sustainable alternative fuels to diesel or gasoline. They are chemically identical but biopropane is obtained from renewable, non-fossil sources, meaning it is substantially better for the environment in terms of sustainability and GHG emissions.
Repsol has been working on sustainable fuel solutions for transport since 2007. Specifically, on LPG, the Repsol Technology Center developed in 2014 a Euro 6c LPG DISI (Direct Injection Spark Ignited) dedicated engine to demonstrate the potentiality of using LPG for reducing the TtW (Tank to Wheels) CO2 emissions and achieve the 2020 goals in light-duty vehicles with common technologies, in a modified gasoline direct injection engine from an existing class C demo vehicle, including a completely new liquified gas direct injection system and new ECU. As a result, the engine was adapted to run with LPG in an optimised injection and combustion process, allowing for a substantial reduction of GHG emissions compared to gasoline: very relevant reduction of nitrogen oxides (NOx) and hydrocarbons (HCs), particulate matter (PM) reduction to almost zero and up to 34% reduction of CO2 emissions in full load. In the video on the right you can see the results of this project.
The knowledge acquired by the Repsol Technology Center for AutoGas direct injection in light vehicle engines is now being leveraged and transferred within the COLHD project to go one step further and improve WtW (Well to Wheels) GHG emissions and raw exhaust emissions on heavy-duty vehicles using a Diesel cycle engine and incorporating biofuels, to be applied to the development of the 480HP Dual-Fuel high pressure engine prototype, running on blends of Diesel/HVO and LPG (AutoGas). Unlike previous developments, the innovative engine now developed in COLHD is a modified diesel engine, so the fuels mixture inside the cylinder will need to auto-ignite, contrary to the previous gasoline engine case. This will therefore represent one of the main technological challenges in COLHD, requiring the modification in the fuel injection and on-board fuel mixing strategies, depending on the engine thermal conditions and loads under real operating conditions.