5 results on '"Ritzmann, Johannes"'
Search Results
2. Model Predictive Supervisory Control for Integrated Emission Management of Diesel Engines
- Author
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Ritzmann, Johannes, Peterhans, Christian, Chinellato, Oscar, Gehlen, Manuel, and Onder, Christopher
- Subjects
aftertreatment system ,model predictive control ,integrated emission management ,supervisory control ,variable engine calibration ,pollutant emissions - Abstract
In this work, a predictive supervisory controller is presented that optimizes the interaction between a diesel engine and its aftertreatment system (ATS). The fuel consumption is minimized while respecting an upper bound on the emitted tailpipe NOx mass. This is achieved by optimally balancing the fuel consumption, the engine-out NOx emissions, and the ATS heating. The proposed predictive supervisory controller employs a two-layer model predictive control structure and solves the optimal control problem using a direct method. Through experimental validation, the resulting controller was shown to reduce the fuel consumption by 1.1% at equivalent tailpipe NOx emissions for the nonroad transient cycle when compared to the operation with a fixed engine calibration. Further, the controller’s robustness to different missions, initial ATS temperatures, NOx limits, and mispredictions was demonstrated., Energies, 15 (8), ISSN:1996-1073
- Published
- 2022
- Full Text
- View/download PDF
3. Optimal Integrated Emission Management through Variable Engine Calibration
- Author
-
Ritzmann, Johannes, Chinellato, Oscar, Hutter, Richard, and Onder, Christopher
- Subjects
variable engine calibration ,pollutant emissions ,supervisory control ,optimal control ,hybrid electric vehicle ,Technology ,ComputerApplications_COMPUTERSINOTHERSYSTEMS - Abstract
In this work, the potential for improving the trade-off between fuel consumption and tailpipe NOx emissions through variable engine calibration (VEC) is demonstrated for both conventional and hybrid electric vehicles (HEV). First, a preoptimization procedure for the engine operation is proposed to address the challenge posed by the large number of engine control inputs. By excluding infeasible and suboptimal operation offline, an engine model is developed that can be evaluated efficiently during online optimization. Next, dynamic programming is used to find the optimal trade-off between fuel consumption and tailpipe NOx emissions for various vehicle configurations and driving missions. Simulation results show that for a conventional vehicle equipped with VEC and gear optimization run on the worldwide harmonized light vehicles test cycle (WLTC), the fuel consumption can be reduced by 5.4% at equivalent NOx emissions. At equivalent fuel consumption, the NOx emissions can be reduced by 80%. For an HEV, the introduction of VEC, in addition to the optimization of the torque split and the gear selection, drastically extended the achievable trade-off between fuel consumption and tailpipe NOx emissions in simulations. Most notably, the region with very low NOx emissions could only be reached with VEC., Energies, 14 (22), ISSN:1996-1073
- Published
- 2021
4. Low-Load Limit in a Diesel-Ignited Gas Engine
- Author
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Hutter, Richard, Ritzmann, Johannes, Elbert, Philipp, and Onder, Christopher H.
- Subjects
low-load strategy ,dual-fuel ,supervisory control - Abstract
The lean-burn capability of the Diesel-ignited gas engine combined with its potential for high efficiency and low CO 2 emissions makes this engine concept one of the most promising alternative fuel converters for passenger cars. Instead of using a spark plug, the ignition relies on the compression-ignited Diesel fuel providing ignition centers for the homogeneous air-gas mixture. In this study the amount of Diesel is reduced to the minimum amount required for the desired ignition. The low-load operation of such an engine is known to be challenging, as hydrocarbon (HC) emissions rise. The objective of this study is to develop optimal low-load operation strategies for the input variables equivalence ratio and exhaust gas recirculation (EGR) rate. A physical engine model helps to investigate three important limitations, namely maximum acceptable HC emissions, minimal CO 2 reduction, and minimal exhaust gas temperature. An important finding is the fact that the high HC emissions under low-load and lean conditions are a consequence of the inability to raise the gas equivalence ratio resulting in a poor flame propagation. The simulations on the various low-load strategies reveal the conflicting demand of lean combustion with low CO 2 emissions and stoichiometric operation with low HC emissions, as well as the minimal feasible dual-fuel load of 3.2 bar brake mean effective pressure. ISSN:1996-1073
- Published
- 2017
5. Low-Load Limit in a Diesel-Ignited Gas Engine
- Author
-
Hutter, Richard, Ritzmann, Johannes, Elbert, Philipp, and Onder, Christopher H.
- Subjects
dual-fuel ,020209 energy ,0202 electrical engineering, electronic engineering, information engineering ,supervisory control ,02 engineering and technology ,low-load strategy - Abstract
The lean-burn capability of the Diesel-ignited gas engine combined with its potential for high efficiency and low CO 2 emissions makes this engine concept one of the most promising alternative fuel converters for passenger cars. Instead of using a spark plug, the ignition relies on the compression-ignited Diesel fuel providing ignition centers for the homogeneous air-gas mixture. In this study the amount of Diesel is reduced to the minimum amount required for the desired ignition. The low-load operation of such an engine is known to be challenging, as hydrocarbon (HC) emissions rise. The objective of this study is to develop optimal low-load operation strategies for the input variables equivalence ratio and exhaust gas recirculation (EGR) rate. A physical engine model helps to investigate three important limitations, namely maximum acceptable HC emissions, minimal CO 2 reduction, and minimal exhaust gas temperature. An important finding is the fact that the high HC emissions under low-load and lean conditions are a consequence of the inability to raise the gas equivalence ratio resulting in a poor flame propagation. The simulations on the various low-load strategies reveal the conflicting demand of lean combustion with low CO 2 emissions and stoichiometric operation with low HC emissions, as well as the minimal feasible dual-fuel load of 3.2 bar brake mean effective pressure., Energies, 10 (10), ISSN:1996-1073
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