Multi Scale Control of PCCI Combustion

• Applicant: Professor Dr. Christopher Onder
• Subject Area: Hydraulic and Turbo Engines and Piston Engines
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 277012063

Since the path to CO2-neutral mobility is not clear and thermalchemicalenergy carriers have significant advantages over electrochemicalenergy carriers, the research and development of novelcombustion engines is of major importance. Low-temperaturecombustion processes such as PCCI (Premixed Charge CompressionIgnition) are a promising technology for increasing the efficiency oftoday's internal combustion engines while simultaneously reducingpollutant emissions. In order to enable stable and fast operation of thePCCI process in a multi-cylinder engine, a coordinated interactionbetween air path and combustion control is required, since thecombustion process reacts sensitively to the air path variablesprovided. Therefore, the air path control must be able to ensure thenecessary thermodynamic state variables in the cylinder for static andtransient operation of the engine. The speed at which the statevariables are provided depends on the design of the existing air pathand its dynamics. Combustion control should use the provided statevariables to compensate for cylinder-specific disturbances for the nextcycle and take into account specified boundary conditions andrestrictions. By using a fully variable valve train, different exhaust gasrecirculation paths and multi-stage turbocharging, a compressionignitedmulti-cylinder engine can use additional degrees of freedom toprovide the desired thermodynamic state variables for the cylinder.The large number of control variables for the air path results indifferent time scales with which the combustion process can beinfluenced. This property can be exploited in a targeted manner bymeans of multi-scale control. Only model- and optimization-basedcontrollers can be considered as a method to adequately take intoaccount the complexity of the controlled system. In order to enable areal-time capable multi-scale control of the air path, simplified modelsand numerically optimized algorithms are required, which aredeveloped in close cooperation with other subprojects of the FORgroup.In a further step the combustion control is to be integrated intothe multi-scale control of the air path in order to consider theinteraction between air path and combustion. The preliminary work ofother subprojects on combustion rateshaping control will be furtherdeveloped for the PCCI process.

• DFG Programme: Research Units
• Subproject of: FOR 2401: Optimization-Based Multiscale Control of Low-Temperature Combustion Engines
• International Connection: Switzerland
• Partner Organisation: Schweizerischer Nationalfonds (SNF)