Model-Based Predictive Control and Dithering Control for an Integrated Gasoline Engine and Three-Way Catalytic Converter System

Author(s):  
Kuo Yang ◽  
Pingen Chen

Abstract Controls of integrated gasoline engine and after-treatment systems are critical for fuel efficiency improvement and emission regulation. This paper aims to develop novel model-based Three-Way Catalytic converter (TWC) controls to reduce the fuel consumption and tailpipe emissions for a gasoline engine. A model-based dither control and a nonlinear model predictive control (MPC)-based control, are presented, respectively. The proposed TWC dither control utilizes a systematically designed dither cycle configuration (including dithering amplitude, offset, and frequency) based on a control-oriented model, with the capability to adapt the dither cycle configuration to various engine operating conditions. The MPC control can optimize engine air-fuel ratio (AFR) to maintain the oxygen storage of TWC at a desired level and thus meet the tailpipe NOx, CO and HC emission requirements. The efficacies of both model-based TWC controls are validated in simulation with MPC control improving CO emission conversion efficiencies by 8.42% and 4.85% in simplified US06 and UDDS driving cycles, when compared to a baseline dithering-based AFR control. Meanwhile, NOx emission conversion efficiency is maintained above the required limit of 95%, while the fuel efficiency remains at the same level as the baseline control methodology.

Author(s):  
Kuo Yang ◽  
Pingen Chen

With increasingly demanding regulations on engine emission and fuel efficiency, the optimization of the internal combustion engine and the after-treatment integrated system has become a critical research focus. To address such an issue, this paper aims to achieve a better trade-off between the fuel consumption of a spark-ignited (SI) engine and emission conversion efficiencies of a Three-Way Catalytic converter (TWC) system. A Model Predictive Control (MPC)-based integrated engine and TWC control methodology is presented, which is able to optimize Air/Fuel Ratio (AFR) to maintain oxygen storage of TWC at a desired level and thus meet the tailpipe NOx, CO and HC emission requirements. The effectiveness of the presented control methodology is validated in simulation. Compared with the existing dithering-based AFR control, the proposed MPC-based AFR control can improve CO emission conversion efficiencies by 8.42% and 4.85% in simplified US06 and UDDS driving cycles, respectively. At the same time, Nitrogen Oxides (NOx) conversion efficiency maintains above the required limit of 95% and the fuel efficiency remains at the same level as the existing control methodology in production as well. Such an integrated engine-aftertreatment system control can be instrumental in improving engine efficiency and emission reduction performance.


2019 ◽  
Vol 9 (21) ◽  
pp. 4610 ◽  
Author(s):  
Dario Di Maio ◽  
Carlo Beatrice ◽  
Valentina Fraioli ◽  
Pierpaolo Napolitano ◽  
Stefano Golini ◽  
...  

The main objective of the present research activity was to investigate the effect of very fast composition transitions of the engine exhaust typical in real-world driving operating conditions, as fuel cutoff phases or engine misfire, on the aftertreatment devices, which are generally very sensitive to these changes. This phenomenon is particularly evident when dealing with engines powered by natural gas, which requires the use of a three-way catalyst (TWC). Indeed, some deviations from the stoichiometric lambda value can interfere with the catalytic converter efficiency. In this work, a numerical “quasi-steady” model was developed to simulate the chemical and transport phenomena of a specific TWC for a compressed natural gas (CNG) heavy-duty engine. A dedicated experimental campaign was performed in order to evaluate the catalyst response to a defined λ variation pattern of the engine exhaust stream, thus providing the data necessary for the numerical model validation. Tests were carried out to reproduce oxygen storage phenomena that make catalyst behavior different from the classic steady-state operating conditions. A surface reaction kinetic mechanism concerning CH4, CO, H2, oxidation and NO reduction has been appropriately calibrated at different λ values with a step-by-step procedure, both in steady-state conditions of the engine work plan and during transient conditions, through cyclical and consecutive transitions of variable frequency between rich and lean phases. The activity also includes a proper calibration of the reactions involving cerium inside the catalyst in order to reproduce oxygen storage and release dynamics. Sensitivity analysis and continuous control of the reaction rate allowed evaluating the impact of each of them on the exhaust composition in several operating conditions. The proposed model predicts tailpipe conversion/formation of the main chemical species, starting from experimental engine-out data, and provides a useful tool to evaluate the catalyst’s performance.


Author(s):  
M I Soumelidis ◽  
R K Stobart ◽  
R A Jackson

Chemical activity inside a three-way catalytic converter (TWC) is highly complex and usually is not taken into account when developing TWC control-oriented models. Such models still remain to a large extent empirical and do not perform satisfactorily under a wider range of operating conditions. This work demonstrates how a very simple model, based on the basic chemical processes that take place inside the catalytic converter, can successfully capture a large part of the strongly non-linear TWC dynamic behaviour. The proposed model is based on the reactions of ceria oxidation and carbon monoxide oxidation, which appear to dominate the fast dynamics of oxygen storage and release respectively. In addition, the water-gas shift reaction is incorporated into the model, which is responsible for the slower dynamic response of the catalyst under rich operating conditions. With some mild assumptions, a discrete-time version of the model was implemented in MATLAB. The model is sufficiently simple in structure for in-vehicle use and can be used for control and on-board diagnostic purposes.


Author(s):  
Pushkar Agashe ◽  
Yang Li ◽  
Bo Chen

This paper presents model-based design and hardware-in-the-loop (HIL) simulation of engine lean operation. The functionalities of the homogeneous combustion subsystem in engine Electronic Control Unit (ECU) in dSPACE Automotive Simulation Models (ASM) are first analyzed. To control the gasoline engine in lean operation without the drop of output torque, the combustion subsystem in engine ECU is modified by introducing two control loops, torque modifier and fuel multiplier. The performance of these two controllers is evaluated by HIL simulation using a dSPACE HIL simulator. The HIL simulation models, including vehicle plant model and softECUs in HIL simulator and engine lean control model in hardware engine ECU are modeled using model-based design. With HIL simulation, the designed engine control strategies can be immediately tested to evaluate the overall vehicle performance. The HIL simulation results show that the designed lean combustion control strategy can reduce fuel consumption and is able to meet the torque requirement at lean engine operating conditions.


Author(s):  
Feihong Xia ◽  
Philip Griefnow ◽  
Florian Tidau ◽  
Moritz Jakoby ◽  
Serge Klein ◽  
...  

48V systems enable not only mild hybrid functionalities such as recuperation or torque assist by a belt-driven starter generator (BSG), but also electrification of accessories and the engine boosting system. To maximize the powertrain efficiency, a proper layout of the electrified system and an optimized distribution of the electric power during transient operation is essential. In this study, a vehicle co-simulation of a conventional powertrain with a downsized turbocharged gasoline engine is extended by a 48V system with an electric compressor (eC) and a BSG. The control functions of the eC and BSG are based on a state-of-the-art vehicle application and calibrated for transient operating conditions. The engine model, which is built using a one-dimensional crank angle resolved approach in GT-POWER, has been validated with measurement data and is used to predict the interaction between the eC and the engine air path. The investigations using the simulation platform show that the 48V eC and the BSG can significantly improve the fuel effïciency if the electric energy consumption is initially neglected. However, when considering the electric energy consumption within the vehicle co-simulation, efficient operation is particularly depending on driver torque demand, the battery state-of-charge and charging effïciency. Hence, intelligent operating strategies are necessary to take advantage of the better torque response and improve fuel consumption at the same time.


2013 ◽  
Vol 300-301 ◽  
pp. 27-31
Author(s):  
Hsu Fang Chang ◽  
Wang Chih Cheng ◽  
Feng Tsai Weng

The method of supplying fuel for an electronic-controlled fuel injection system is calculating the required fuel amounts under various operating conditions of engine and controlling the opening and closing timing of fuel injection. After fuel injection, the effects of condensation and atomization of injected fuel as well as fuel mixing for combustion are strongly dominated by the opening timing and duration of intake valves. This can further affect the emission composition and performance for an engine. As the emission regulation is getting more stringent and the requirement for minimizing specific fuel consumption is becoming more urgent, investigating the effect of closing timing of fuel injection has turned out to be a major issue. Therefore, this paper presents a study about a series of engine tests to investigate the effect of end of injection angle on the performance and emission formation for a gasoline engine. In these tests, the values of end of injection angle are adjusted using a control software for electronic-controlled fuel injection system so that the results can be analyzed under various engine speeds and loads.


2021 ◽  
Vol 1 (50) ◽  
pp. 198-209
Author(s):  
Sakhno V ◽  
◽  
Dykich O ◽  

The article considers the issue of choosing a gearbox for the modernization of the BTR-70 by replacing two gasoline engines with two diesels. The object of research is the fuel economy of the BTR-70 car with different gearboxes when replacing two gasoline engines with two diesels. The purpose of the work – to determine the type and gear ratio of the transmission, which provides the best fuel efficiency of the car. Research method - mathematical modeling. When replacing a gasoline engine with a diesel of a different power and a different speed range, it is necessary to determine the gear ratio so as to provide the car with the required level of speed properties in the specified operating conditions with minimal fuel consumption. Due to the fact that the modernization of the BTR-70 involves the replacement of the engine and transmission, the further search for the gearbox was carried out on the basis of analysis of existing structures by the maximum torque of the engine. A five-speed and eight-speed MAZ gearbox and a six-speed Mercedes-Benz G 85-6 / 6.7 gearbox were used for analysis. Taking into account the fact that at a given coefficient of drag  = 0.03 the car can move only in direct gear, then for all gearboxes the fuel characteristics of steady motion will be the same as the control fuel consumption, which was 30 l / 100 km. In terms of fuel consumption during the acceleration of the car and the average kilometer fuel consumption when driving on paved roads, preference should be given to a car with a Mercedes-Benz G 85-6 / 6,7 transmission and only when driving in difficult road conditions, preference should be given to the car with 8-speed MAZ-5335 transmission. KEY WORDS: CAR, ENGINE, FUEL ECONOMY, TRANSMISSION, GEAR RATING, SPEED, COMPARATIVE EVALUATION


1998 ◽  
Vol 20 (2) ◽  
pp. 103-112 ◽  
Author(s):  
B. Lennox ◽  
G.A. Montague ◽  
A.M. Frith ◽  
A.J. Beaumont

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