Internal Combustion Engines
Continuous CO2-reduction, reduction of tailpipe emissions and reduction of system complexity are the three cornerstones of the topic internal combustion engines. The basic measures to reduce CO2 output are efficiency increase and use of alternative fuels. Optimizing all combustion-related parameters and the close coupling between combustion process and exhaust aftertreatment are the main tasks to decrease emissions. The goal of an overall system complexity reduction is for example the release of the cooling system, the reduction of the amount of precious metal in catalyst substrates or reduced demands on an ECU by enhanced control strategies. The work on these topics is performed in seven priority areas.
Combustion process: The focus of combustion process development is on the reduction of tailpipe emissions and the increase of engine efficiency. Therefore, a detailed optical and thermodynamic analysis of the process is performed to generate fundamental understanding of the influencing effects to derive optimization measures.
Engine system and exhaust gas aftertreatment: To develop expedient and efficient solutions the engine must be considered as a complex overall system due to the strong interaction of all relevant subsystems such as air path, boosting, injection, combustion, exhaust aftertreatment, thermal management, waste heat recovery and hybridization.
Emissions: Research on the formation mechanisms of limited emissions such as carbon monoxide, hydrocarbons, nitric oxides, soot or particles in the combustion chamber is performed in this area. Latest temporal and spatially resolving optical measurement techniques are used as well as theoretical reaction kinetic approaches. The knowledge gained enables to derive combustion process related measures to reduce emissions.
Oil circuit and aerosols: Oily aerosols from the crank case ventilation of current engines negatively influence the thermodynamic behavior and lead to component damage by fouling or deposit formation. In this area fundamental formation mechanisms are investigated and new measurement techniques and sustainable mitigation strategies are developed.
Waste heat recovery: The use of the exergetic potential of exhaust gas, cooling water and further wells will increasingly gain in importance. By means of a Clausius-Rankine-Cycle of the first generation using only exhaust gas energy it is possible to achieve a fuel economy advantage of about 4% depending on engine design, driving cycle and overall system design. A potential of more than 10% is realistic in the long term and is subject of current investigations.
Alternative fuels: The indispensable way to sustainable mobility is possible in the long term by using renewably produced fuels. Hydrocarbons and oxygenates are possible alternatives. The choice of suitable fuels and their optimization concerning combustion and exhaust gas aftertreatment with regard to application-specific characteristics are in focus of research activities.
Combined Heat and Power Systems: The combined use of heat and power in a CHP leads to an efficiency of more than 85% related to the primary energy carrier. The supply of buildings - no matter whether private or industrial - is economically promising. The higher the efficiency of the electrical path the better is the overall performance. In this area the increase of the efficiency of the combustion process is subject of research.
Affiliated Institutes:
Institute of Internal Combustion Engines (IFKM)
Institute of Technical Thermodynamics (ITT)
Institute of Thermal Turbo Machines(ITS)