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In this work, the potential of laser-induced ignition to improve combustion initiation and heat release in a direct-injection engine is investigated by a combined experimental and numerical investigation. Laser ignition is studied in fuel/air mixtures with homogeneous equivalence ratio fields. The results provide knowledge about minimum ignition energies and the ignition limits of laser-induced ignition. Furthermore, in mixtures with nominally identical conditions, statistical variations of the ignition success are observed experimentally. These variations can be explained, based on numerical simulations, by fluctuations in the strain rate in the turbulent in-cylinder flow. Additionally, laser ignition in engines with a spray-guided combustion mode, with strongly inhomogeneous fuel/air mixtures, was investigated.

As an important means of engine development and optimization, modelbuilding plays an increasingly important role in reducing carbon dioxide emissions of the internal combustion engines (ICEs). However, due to the non-linearity and high dimension of the engine system, a large amount of data is required to obtain high model accuracy. Therefore, a modelling approach combining the experimental data and prior knowledge was proposed in this study. With this method, an artificial neural network (ANN) model simulating the engine brake specific fuel consumption (BSFC) was established. With mean square error (MSE) and Kullback-Leibler divergence (KLD) serving as the fitness functions, the 86 experimental samples and constructed physical models were used to optimize the ANN weights through genetic algorithms.

The need for carbon-neutral transportation solutions has never been more pronounced. With the continually expanding volume of goods in transit, innovative and dependable powertrain concepts for freight transport are imperative. The green hydrogen-powered internal combustion engine presents an appealing option for integrating a reliable, non-fossil fuel powertrain into commercial vehicles. This study focuses on the adaptation of a single-cylinder diesel engine with a displacement of 2116 cm3 to facilitate hydrogen combustion. The engine, characterized by low levels of swirl and tumble, underwent modifications, including the integration of a conventional central spark plug, a custom-designed piston featuring a reduced compression ratio of 9.5, and a low-pressure hydrogen direct injection system. Operating the injection system at 25 bar hydrogen pressure, the resulting jet profiles were varied by employing jet forming caps affixed directly to the injector nozzle.