Expansion of VECTO to include methods for fuel cell vehicles
Project duration: 2021 - 2024
Project partner: HyCentA
Funded by: EU, Horizon 2020 Projekt
Project team: Silberholz, Martini, Quaritsch, Rexeis
Since 2010, the Emissions research department has been significantly involved in the development of an EU-wide standardised test procedure for determining the CO2 emissions of heavy commercial vehicles (SNF). The procedure is based on measuring the energy requirements and efficiency of the individual vehicle components and simulating the fuel consumption and CO2 emissions of the entire vehicle using the "VECTO" (Vehicle Energy Consumption Calculation Tool) software. Since July 2019, every newly registered long-distance lorry must have an individual CO2 value determined using VECTO entered in the vehicle documents. Other lorry classes and buses will follow by the beginning of 2024. These vehicle-specific CO2 values also form the basis for the CO2 fleet target values that manufacturers must comply with in the coming years compared to 2019 (2025: minus 15%; 2030: minus 45%, 2040 minus 90%, values from 2030 onwards currently still under negotiation).
In future, VECTO will also determine the energy consumption and achievable range in kilometres for HDVs with alternative drive systems. In order to be able to map fuel cell vehicles in VECTO, work is currently being carried out in close cooperation with the vehicle industry and suppliers on the two necessary elements of component testing and simulation methods in VECTO.
The component test for fuel cell systems (FCS) is used to determine the hydrogen consumption and thus the efficiency of the FCS under various load conditions under certification conditions. The test procedure consists of a sequence of stationary load points that are run through in a fixed order. One challenge in test development is to ensure the comparability of the results for the various possible configurations of FCS (arrangement of stacks, pumps and power electronics). This is ensured by applying various correction functions to the measurement results.
A generic strategy for the operation of the FCS is being developed for modelling the fuel cell vehicle in VECTO. This should be suitable for all possible vehicle configurations (dimensioning of FCS and battery) and application profiles (long-distance transport to city bus cycles) and deliver comparable results. The basic approach of the strategy is to phlegmatise FCS operation as far as possible in order to achieve optimum efficiency and service life of the component. The most important boundary conditions are the vehicle's electrical energy consumption (vehicle specification and driving cycle) and the capacity of the installed battery.
Figure 1 shows an example of the simulation of a 40-tonne articulated lorry in a long-distance transport cycle with two different battery sizes (60 kWh "large" and 20 kWh "small"). The electrical power requirement of the vehicle is shown in black, the electrical power output of the FCS in the two vehicle variants in red and orange and the SOC curves of the battery variants in blue. In the vehicle variant with the larger battery, the FCS can be operated at a constant operating point and a 15% lower hydrogen consumption (8.6 kg/100km) can be achieved compared to the small variant (10.1 kg/100km).
Figure1: FCS operating points and SOC curves for a 40-tonne articulated lorry in the long-distance transport cycle for 2 different battery variants.