Exhaust valve phasing controllers for cold start NOx emissions reduction in heavy duty diesel engines

2021 ◽  
pp. 146808742199651
Author(s):  
Rasoul Salehi ◽  
Robert J Middleton
Keyword(s):  
Operating Conditions ◽  
Exhaust Valve ◽  
Emissions Reduction ◽  
Drive Cycle ◽  
Test Drive ◽  
Rule Based ◽  
Warm Up ◽  
Model Based ◽  
Predictive Controller ◽  
Scr System

In this paper, early exhaust valve opening (EVO) is applied to a diesel engine for fast warm up of the selective catalytic reduction (SCR) system with the ultimate goal of tailpipe NOx emissions reduction. By advancing EVO from top dead center, the exhaust gas temperature increases and the exhaust flow reduces, influencing the enthalpy available to warm up the SCR, and the engine-out NOx emissions increase or decrease depending on the engine’s operating conditions. Therefore, proper management of EVO is required to ensure that (1) engine-out NOx emissions do not increase when the SCR catalyst is cold; (2) heat transfer to the SCR increases and it warms up faster than the baseline operation (without EVO phasing); and (3) fuel consumption increase is minimal. A novel model predictive controller (MPC) is proposed for this application, assuming a limited preview of the drive cycle is available. For the MPC, an optimization objective function is applied such that a sequential warm up strategy can be implemented for the aftertreatment system catalysts. Using this technique, the prediction horizon for effective thermal management of the slow SCR system is reduced. In addition, a rule-based logic is offered as an alternative to the predictive controller to calculate the EVO trajectory with less computational power. Observations based on optimization problems solved by dynamic programing (DP) were used to develop the rule-based controller. Both the rule-based logic and model-based MPC are tested with a detailed high fidelity one-dimensional model in a model-in-the-loop simulator. Results indicate the potential of an EVO phasing system with the proposed controllers to reduce tailpipe NOx by 10% and 25% for the world harmonized transient cycle (WHTC) and federal test procedure (FTP), respectively. The rule-based controller has been found to be sensitive to the test drive cycle while the model based MPC shows a consistent performance, that is, independent of the test trajectory.

Computationally Efficient Urea-Dosing Controllers for Urea-SCR

2020 ◽  
Author(s):  
Rajakumar Ganne ◽  
Kaushal K. Jain ◽  
Peter H. Meckl ◽  
Harshil Angre ◽  
Jagdish R. Hiremath
Keyword(s):  
Computational Cost ◽  
Computationally Efficient ◽  
Trade Off ◽  
Model Based ◽  
Control Objective ◽  
Predictive Controller ◽  
Simulation Results ◽  
Scr System

Abstract This paper presents two non-model-based reference-shaping and a model-based predictive urea-dosing controller for the Urea-SCR system. An ideal urea-dosing controller would minimize both tailpipe NOx and NH3 slip. However, this is not possible because of the trade-off between deNOx and NH3 slip. This trade-off is used to clearly define a control objective in terms of NH3 slip. Three controllers are then developed to meet this control objective such that they are all computationally inexpensive. The three controllers are then tested for three very different drive cycles. Simulation results show that the performance of the non-model based reference-shaping controllers is subjected to manual tuning of their variables. In contrast, the predictive controller, which is the highlight of this paper, can adapt to various drive cycles without compromising on the computational cost.

scholarly journals Evaluation of the test drive cycle conditions impact on exhaust emissions from an internal combustion engine

2018 ◽  
Vol 175 (4) ◽  
pp. 3-9
Author(s):  
Monika ANDRYCH-ZALEWSKA ◽  
Zdzisław CHŁOPEK ◽  
Jerzy MERKISZ ◽  
Jacek PIELECHA
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Nitrogen Oxides ◽  
Exhaust Emissions ◽  
Operating Conditions ◽  
Exhaust Emission ◽  
Test Results ◽  
Drive Cycle ◽  
Test Drive ◽  
The Mean

Test results of exhaust emission sensitivity to engine operating conditions from a vehicle with a compression ignition engine have been analyzed. These results were determined in driving tests: NEDC (New European Driving Cycle), RDE (Real Driving Emissions) and Malta, an original drive cycle developed at Poznan University of Technology. The tests in the NEDC and Malta cycles were carried out on the engine dynamometer in driving tests simulation conditions, while the RDE test was carried out in the real conditions of passenger car traffic. The mean exhaust emission test results of carbon monoxide, hydrocarbons, nitrogen oxides and carbon dioxide as well as the mean particle number in individual tests have been provided. A high sensitivity of the tested emission values to the changes in engines operating conditions was found, both for static and dynamic conditions. The strongest impact of engine operating conditions was found for hydrocarbons emissions and the number of particles, followed by carbon monoxide, a smaller impact was found for nitrogen oxides and carbon dioxide. The largest differences in the values characterizing exhaust emissions were found for the NEDC test, which differed the most in dynamic engine operating conditions from other tests that closer resemble real driving conditions of vehicles.

Implementing variable valve actuation on a diesel engine at high-speed idle operation for improved aftertreatment warm-up

2019 ◽  
Vol 21 (7) ◽  
pp. 1134-1146
Author(s):  
Kalen R Vos ◽  
Gregory M Shaver ◽  
Mrunal C Joshi ◽  
James McCarthy
Keyword(s):  
Particulate Matter ◽  
High Speed ◽  
Exhaust Valve ◽  
Exhaust Gas ◽  
Warm Up ◽  
Aftertreatment System ◽  
Idle Speed ◽  
Variable Valve Actuation ◽  
Brake Mean Effective Pressure ◽  
Valve Opening

Aftertreatment thermal management is critical for regulating emissions in modern diesel engines. Elevated engine-out temperatures and mass flows are effective at increasing the temperature of an aftertreatment system to enable efficient emission reduction. In this effort, experiments and analysis demonstrated that increasing the idle speed, while maintaining the same idle load, enables improved aftertreatment “warm-up” performance with engine-out NOx and particulate matter levels no higher than a state-of-the-art thermal calibration at conventional idle operation (800 rpm and 1.3 bar brake mean effective pressure). Elevated idle speeds of 1000 and 1200 rpm, compared to conventional idle at 800 rpm, realized 31%–51% increase in exhaust flow and 25 °C–40 °C increase in engine-out temperature, respectively. This study also demonstrated additional engine-out temperature benefits at all three idle speeds considered (800, 1000, and 1200 rpm, without compromising the exhaust flow rates or emissions, by modulating the exhaust valve opening timing. Early exhaust valve opening realizes up to ~51% increase in exhaust flow and 50 °C increase in engine-out temperature relative to conventional idle operation by forcing the engine to work harder via an early blowdown of the exhaust gas. This early blowdown of exhaust gas also reduces the time available for particulate matter oxidization, effectively limiting the ability to elevate engine-out temperatures for the early exhaust valve opening strategy. Alternatively, late exhaust valve opening realizes up to ~51% increase in exhaust flow and 91 °C increase in engine-out temperature relative to conventional idle operation by forcing the engine to work harder to pump in-cylinder gases across a smaller exhaust valve opening. In short, this study demonstrates how increased idle speeds, and exhaust valve opening modulation, individually or combined, can be used to significantly increase the “warm-up” rate of an aftertreatment system.

Study On Automatic Adaptation for Control-Oriented Model of Advanced Diesel Engine

2021 ◽  
Author(s):  
Shunki Nishii ◽  
Yudai Yamasaki
Keyword(s):  
Operating Conditions ◽  
Physical Models ◽  
Model Parameters ◽  
Training Methods ◽  
Model Based Control ◽  
Practical Applications ◽  
Model Based ◽  
Automatic Adaptation ◽  
Automobile Engines ◽  
Adaptation Method

Abstract To achieve high thermal efficiency and low emission in automobile engines, advanced combustion technologies using compression autoignition of premixtures have been studied, and model-based control has attracted attention for their practical applications. Although simplified physical models have been developed for model-based control, appropriate values for their model parameters vary depending on the operating conditions, the engine driving environment, and the engine aging. Herein, we studied an onboard adaptation method of model parameters in a heat release rate (HRR) model. This method adapts the model parameters using neural networks (NNs) considering the operating conditions and can respond to the driving environment and the engine aging by training the NNs onboard. Detailed studies were conducted regarding the training methods. Furthermore, the effectiveness of this adaptation method was confirmed by evaluating the prediction accuracy of the HRR model and model-based control experiments.

scholarly journals Emissions and In-Cylinder Combustion Characteristics of Fischer-Tropsch and Conventional Diesel Fuels in a Modern CI Engine

2005 ◽  
Author(s):  
Alexander G. Sappok ◽  
Jeremy T. Llaniguez ◽  
Joseph Acar ◽  
Victor W. Wong
Keyword(s):  
Combustion Characteristics ◽  
Operating Conditions ◽  
Fuel Properties ◽  
Emissions Reduction ◽  
Cylinder Pressure ◽  
Fischer Tropsch ◽  
Diesel Fuels ◽  
Ultra Low Sulfur Diesel ◽  
Low Sulfur ◽  
Detailed Chemical

Derived from natural gas, coal, and even biomass Fischer-Tropsch (F-T) diesel fuels have a number of very desirable properties. The potential for emissions reduction with F-T diesel fuels in laboratory engine tests and on-road vehicle tests is well documented. While a number of chemical and physical characteristics of F-T fuels have been attributed to the observed reduction in emissions, the actual effects of both the fuel properties and in-cylinder combustion characteristics in modern diesel engines are still not well understood. In this study a 2002, six-cylinder, 5.9 liter, Cummins ISB 300 diesel engine, outfitted with an in-cylinder pressure transducer. was subjected to a subset of the Euro III 13-mode test cycle under steady-state operating conditions. Emissions and in-cylinder pressure measurements were conducted for neat F-T diesel, low sulfur diesel (LSD), ultra-low sulfur diesel (ULSD), and a blend of FT/LSD. In addition, a detailed chemical analysis of the fuels was carried out. The differences in the measured combustion characteristics and fuel properties were compared to the emissions variations between the fuels studied, and an explanation for the observed emissions behavior of the fuels was developed.

scholarly journals A New Approach to Multiple Fault Diagnosis: A Combination of Diagnostic Matrices, Graphs, Algebraic and Rule-Based Models. The Case of Two-Layer Models

2008 ◽  
Vol 18 (4) ◽  
pp. 465-476 ◽  
Author(s):  
Antoni Ligęza ◽  
Jan Kościelny
Keyword(s):  
Fault Diagnosis ◽  
Simultaneous Occurrence ◽  
Diagnostic Model ◽  
Rule Based ◽  
New Approach ◽  
Multiple Fault ◽  
Multiple Faults ◽  
Model Based ◽  
Multiple Fault Diagnosis ◽  
System Variables

A New Approach to Multiple Fault Diagnosis: A Combination of Diagnostic Matrices, Graphs, Algebraic and Rule-Based Models. The Case of Two-Layer ModelsThe diagnosis of multiple faults is significantly more difficult than singular fault diagnosis. However, in realistic industrial systems the possibility of simultaneous occurrence of multiple faults must be taken into account. This paper investigates some of the limitations of the diagnostic model based on the simple binary diagnostic matrix in the case of multiple faults. Several possible interpretations of the diagnostic matrix with rule-based systems are provided and analyzed. A proposal of an extension of the basic, single-level model based on diagnostic matrices to a two-level one, founded on causal analysis and incorporating an OR and an AND matrix is put forward. An approach to the diagnosis of multiple faults based on inconsistency analysis is outlined, and a refinement procedure using a qualitative model of dependencies among system variables is sketched out.

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