Thermomanagement eines Lastkraftwagens mit Brennstoffzellenantrieb

Translated title of the contribution: Thermal Management of a heavy-duty Truck with Fuel Cell Drive

Research output: ThesisMaster's Thesis

Abstract

To slow down climate change, European legislation has decided to examine the CO2-emissions of heavy-duty trucks from 2025 on. As a result of this, the fleet consumption must be reduced by 30% until 2030. One way to achieve this goal is to use a truck with a fuel cell drive, since this concept does not produce any emissions locally. The fuel required for the fuel cell drive, which is hydrogen, can be obtained emission-free from solar energy in the best case.
The use of a fuel cell drive in heavy-duty trucks is still fairly new and brings some challenges with it. The two biggest challenges in thermal management of the fuel cell are the high amounts of heat to be dissipated and the low temperature level of the coolant. In the worst case, the amounts of heat, dissipated by the coolant, can be just as high as the effective power provided by the fuel cell. The temperature level of the coolant must be kept in the range of 60-80 °C. Another challenge is the fuel cell operating strategy. Load changes as well as start-stop operations damage the fuel cell excessively, therefore favours a stationary operation. However, since the power demand on the wheel is dynamic, the power missing from stationary operation of the fuel cell must be provided by a lithium-ion-battery. This battery must be operated in the temperature range of 20-40 ° C to avoid excessive aging and thus implies the use of a complex thermal management.
The aim of this work is to build a complete vehicle simulation from publicly available literature. The simulation is carried out as a co-simulation with both programs MATLAB Simulink and KULI. The backward-calculating vehicle simulation computes the power applied to the electric motor from the speed profile and the gradient of the driving cycle. Depending on the operating strategy, the electrical power of the electric motor and the auxiliary components is divided between the fuel cell and the battery. The temperature control of the electric motor, fuel cell, battery and the truck cabin are considered in the overall vehicle simulation. All of the subsystems require temperature control at different levels and therefore also different operating strategies. This means that each subsystem has a separate cooling cycle. However, some circuits are coupled with one another, which enables for example to use the waste heat from the fuel cell to heat the truck cabin.
The vehicle simulation is carried out with two climatic boundary conditions, one for summer and one for winter. Two driving cycles are considered. On the one hand, an overland cycle and, on the other hand, a high-load cycle that includes a long uphill section. An analysis of the fuel cell's operating strategy has been carried out. A distinction has been made between a fuel cell dynamic and a fuel cell stationary strategy. The latter proved to be more beneficial and was used to evaluate the cooling circuits. The heat exchangers and coolant pumps of the circuits were determined by means of an optimization in KULI. The cooler surface of the fuel cell has to be around 1.3 m². The evaluation of the cooling circuits confirmed the performance of the thermal management concept. In the final energy balance, an overall vehicle efficiency of 32.99 % in summer and 33.16 % in winter was determined.
Translated title of the contributionThermal Management of a heavy-duty Truck with Fuel Cell Drive
Original languageGerman
QualificationMaster of Science
Awarding Institution
  • Graz University of Technology (90000)
Supervisors/Advisors
  • Eichlseder, Helmut, Supervisor
  • Schutting, Eberhard, Supervisor
  • Reithuber, Peter, Supervisor
Award date23 Mar 2021
Publication statusPublished - 23 Mar 2021

Fields of Expertise

  • Mobility & Production
  • Sustainable Systems

Treatment code (Nähere Zuordnung)

  • Application

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