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The majority of powertrain types considered important contributors to achieving the CO2 targets in the transportation sector employ a battery as an energy storage device. The need for batteries is hence expected to grow drastically with increasing market share of CO2-optimized powertrain concepts. The resulting huge pressure on the development of future electrochemical energy storage systems necessitates the application of advanced methodologies enabling a fast and cost-efficient concept definition and optimization process. This paper presents a model-based methodology for the optimization of BEV thermal management concept layouts and operation strategies targeting minimized energy consumption. Starting at the vehicle level, the proposed methodology combines appropriate representations of all primary powertrain components with 1D cooling and refrigerant circuit models and focuses on their interaction with the battery chemistry.

Reduction of the CO2 greenhouse gas emissions is one major challenge the automotive industry as a part of the transportation sector is facing. Hydrogen is regarded as one of the key energy solutions for CO2 reduction in the future transportation sector. First, a hydrogen-powered single-cylinder test rig for 2 liter heavy-duty engine will be introduced. Followed by a discussion of experimental results including variations of engine speed, torque, ignition strategy, air-fuel ratio, etc. In addition, the paper proposes a new phenomenological model for the prediction of hydrogen combustion. The model is based on the well-known two-zone Entrainment approach, supported by newly developed hydrogen-specific submodels for the calculation of the laminar flame speed and auto-ignition in the unburned mass zone. The developed physical-based combustion model is extensively validated based on the experimental single-cylinder results.

A practical Gasoline Compression Ignition (GCI) concept is presented that works on standard European 95 RON E10 gasoline over the whole speed/load range. A spark is employed to assist the gasoline autoignition at low loads; this avoids the requirement of a complex cam profile to control the local mixture temperature for reliable autoignition. The combustion phasing is controlled by the injection pattern and timing, and a sufficient degree of stratification is needed to control the maximum rate of pressure rise and prevent knock. With active control of the swirl level, the combustion system is found to be relatively robust against variability in charge motion, and subtle differences in fuel reactivity. Results show that the new concept can achieve very low fuel consumption over a significant portion of the speed/load map, equivalent to diesel efficiency. The efficiency is worse than an equivalent diesel engine only at low load where the combustion assistance operates.

At specific operating conditions, the auto-ignition in the unburnt mixture that precedes the occurrence of knock in conventional SI engines happens in two stages. In a previous publication, the authors demonstrated that the low-temperature heat release significantly influences the auto-ignition behavior of the mixture, thus severely impairing the prediction capabilities of the Livengood-Wu integral that the majority of the commonly used 0D/1D knock models are based on. Consequently, a new two-stage auto-ignition prediction approach for modeling the progress of the chemical reactions was introduced. It was demonstrated that the proposed auto-ignition model predicts the occurrence of two-stage ignition and accurately considers the significant influence of low-temperature heat release on the mixture’s auto-ignition behavior at various operating conditions.

The most significant operation limit prohibiting the further reduction of the CO2 emissions of gasoline engines is the occurrence of knock. Thus, being able to predict the incidence of this phenomenon is of vital importance for the engine process simulation - a tool widely used in the engine development. Common knock models in the 0D/1D simulation are based on the calculation of a pre-reaction state of the unburnt mixture (also called knock integral), which is a simplified approach for modeling the progress of the chemical reactions in the end gas where knock occurs. Simulations of thousands of knocking single working cycles with a model representing the Entrainment model’s unburnt zone were performed using a detailed chemical reaction mechanism. The investigations showed that, at specific boundary conditions, the auto-ignition of the unburnt mixture resulting in knock happens in two stages.