The project "Exhaust gas turbocharger for lean concepts" is concerned with the numerically supported development of a single-stage axial turbine exhaust gas turbocharger for turbocharging a petrol engine operated with λ = 2 in the area of the Worldwide Harmonized Light-Duty Vehicles Test Cycle (WLTC). The research question is being worked on as a cooperation between the Institute of Turbomachinery and Fluid Dynamics at Leibniz Universität Hannover and the Institute of Internal Combustion Engines at Technische Universität Braunschweig over a period of 1.5 years.
In recent years, CO2 limits have been steadily tightened. Various technologies have been developed to meet these requirements. One of these technologies is the downsizing of petrol engines. Air dilution increases the indicated engine efficiency and reduces fuel consumption. However, lean combustion has an impact on the exhaust gas properties and thus on the exhaust gas turbocharger (ATL). This creates direct interfaces with the ICE2025+ and ICE2030 projects. Such a turbocharging unit is essential for the overall efficiency of an internal combustion engine and is what makes lean-burn operation possible in the first place.
In lean-burn operation, the operating range limits of single-stage ATL limit the lean-burn operating range in the engine map. To solve this problem, a single-stage system is being developed numerically in the "ATL for lean-burn concepts" project in order to cover the WLTC-relevant operating range of a gasoline engine with λ=2.
First, a full engine model must be realistically mapped within the simulation environment and lean-burn combustion must be implemented. Based on this, the requirements for the charging system in lean-burn operation are identified. In the next step, the project partner can use the data to design a turbine and a compressor. The numerically generated maps can then be fed back into the engine simulation and the performance of the system can be evaluated in relation to the project objective.