Comparison of Measured and Predicted Three-Way Catalyst Conversion Efficiencies under Dynamic Air-Fuel Ratio Conditions

1982 ◽  
Author(s):  
M. A. Shulman ◽  
D. R. Hamburg ◽  
M. J. Throop
Keyword(s):  
Fuel Ratio ◽  
Conversion Efficiencies ◽  
Three Way Catalyst

Model Predictive Air-Fuel Ratio Control for an Integrated Gasoline Engine and Three-Way Catalytic Converter System

2018 ◽  
Author(s):  
Kuo Yang ◽  
Pingen Chen
Keyword(s):  
Gasoline Engine ◽  
Combustion Engine ◽  
Catalytic Converter ◽  
Fuel Efficiency ◽  
Integrated System ◽  
Oxygen Storage ◽  
System Control ◽  
Fuel Ratio ◽  
Conversion Efficiencies ◽  
Control Methodology

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.

Measurements of in-cylinder mixture strength and fuel accumulation in the inlet port of a gasoline - injected engine during very rapid throttle openings

1998 ◽  
Vol 212 (2) ◽  
pp. 103-118 ◽  
Author(s):  
N Ladommatos ◽  
D Rose
Keyword(s):  
Engine Speed ◽  
Gasoline Engine ◽  
Fuel Injection ◽  
Spark Ignition Engine ◽  
Fuel Injectors ◽  
Inlet Port ◽  
Fuel Ratio ◽  
Fuel Accumulation ◽  
Engine Coolant ◽  
Three Way Catalyst

The mixture strength in a cylinder of a port-injected gasoline engine was monitored continuously during very rapid throttle openings. The data on mixture strength were combined with other engine data collected in order to obtain for each successive engine cycle: the air—fuel ratio within the cylinder and the change in the fuel mass accumulating on the inlet port of the cylinder being monitored. The four-cylinder spark-ignition engine used had a displacement of 1.6 litre, four valves per cylinder and multipoint sequential fuel injection controlled by an electronic management system programmed for three - way catalyst operation. All tests were conducted with the engine coolant at the temperature of 90°C and at a constant engine speed of 2000 r/min. The engine transient involved very rapid throttle openings which were completed within about 15 ms. Small and large throttle openings were investigated along with the effect of altering the type and condition of the fuel injectors. The engine response to the fast throttle opening comprised a sharp rise in the air—fuel ratio (maximum gravimetric air—fuel ratio of around 25:1) which lasted for only a single cycle, followed by a drop in the air-fuel ratio (minimum air—fuel ratio of about 10:1) and, subsequently, a gradual rise towards a stoichiometric air—fuel ratio within about 10 engine cycles.

Dynamic Response of Automotive Catalytic Converters to Variations in Air-Fuel Ratio

2003 ◽  
Vol 125 (2) ◽  
pp. 547-554 ◽  
Author(s):  
T. Shamim ◽  
V. C. Medisetty
Keyword(s):  
Dynamic Response ◽  
Coupling Effect ◽  
Chemical Mechanism ◽  
Catalytic Converters ◽  
Engine Exhaust ◽  
Fuel Ratio ◽  
Flow Through ◽  
Automotive Catalytic Converters ◽  
Conversion Efficiencies ◽  
The Mathematical Model

The automotive catalytic converters, which are employed to reduce engine exhaust emissions, operate in transient conditions under all modes of operation. The fluctuation in air-fuel ratio is a major contributor to these transients. The consideration of these transients is essential in accurate modeling of catalyst operation during actual driving conditions. In this work, a numerical investigation is carried out to comprehend the dynamic response of three-way catalytic converters subjected to changes in air-fuel ratio. The mathematical model considers the coupling effect of heat and mass transfer with the catalyst reactions as exhaust gases flow through the catalyst. The converter dynamic response is studied by considering a converter operating under steady conditions, which is suddenly subjected to air-fuel ratio variations. Two types of imposed fluctuations (sinusoidal and step changes) are considered. The catalyst response is predicted by using a detailed chemical mechanism. The paper elucidates the effect of air-fuel modulations on the catalyst HC, CO, and NO conversion efficiencies.

Air-to-fuel Ratio Modulation Experiments over a Pd/Rh Three-way Catalyst

2001 ◽  
Author(s):  
Stephen J. Cornelius ◽  
Nick Collings ◽  
Keith Glover ◽  
Daniel E. Davison
Keyword(s):  
Fuel Ratio ◽  
Three Way Catalyst

Relationship between Backpressure and Light-Off Characteristic of the Three-Way Catalyst

2010 ◽  
Vol 177 ◽  
pp. 682-685
Author(s):  
Xiao Kun He ◽  
Jin Hu ◽  
Yong Bo Ji ◽  
Wen Yong Yang ◽  
Jia Lin Sun
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Cell Shape ◽  
Experimental Results ◽  
Negative Effects ◽  
Fuel Ratio ◽  
Simulating Calculation ◽  
Bench Experiment ◽  
Three Way Catalyst

The three-way catalyst with different cell shape substrates was prepared by the different washcoat loadings. Its catalyst’s light-off characteristics were investigated by the simulating calculation and the engine bench experiment. The experimental results showed that, heat transfer coefficient (Hs) couldn’t be improved by the increase of coating rate, in contrast heat transfer coefficient (Hs) and the catalytic conversion decreased when the coating rate was more than 45%. Therefore, it had some negative effects on the light-off characteristics and air-fuel ratio property. The calculation analyses and the engine bench experiment also proved that the best coating rate was 45% for the substrate of 400cpsi.

Dynamic Response of Automotive Catalytic Converters to Variations in Air-Fuel Ratio

2001 ◽  
Author(s):  
Tariq Shamim ◽  
Vishnu C. Medisetty
Keyword(s):  
Dynamic Response ◽  
Coupling Effect ◽  
Chemical Mechanism ◽  
Catalytic Converters ◽  
Engine Exhaust ◽  
Fuel Ratio ◽  
Flow Through ◽  
Automotive Catalytic Converters ◽  
Conversion Efficiencies ◽  
The Mathematical Model

Abstract The automotive catalytic converters, which are employed to reduce engine exhaust emissions, operate in transient conditions under all modes of operation. The fluctuation in air-fuel ratio is a major contributor to these transients. The consideration of these transients is essential in accurate modeling of catalyst operation during actual driving conditions. In this work, a numerical investigation is carried out to comprehend the dynamic response of three-way catalytic converters subjected to changes in air-fuel ratio. The mathematical model considers the coupling effect of heat and mass transfer with the catalyst reactions as exhaust gases flow through the catalyst. The converter dynamic response is studied by considering a converter operating under steady conditions, which is suddenly subjected to air-fuel ratio variations. Two types of imposed fluctuations (sinusoidal and step changes) are considered. The catalyst response is predicted by using a detailed chemical mechanism. The paper elucidates the effect of air-fuel modulations on the catalyst HC, CO, and NO conversion efficiencies.

Modulated fuel feedback control of a fuel injection engine using a switch type oxygen sensor

1997 ◽  
Vol 211 (6) ◽  
pp. 491-497 ◽  
Author(s):  
K S Park ◽  
J Park ◽  
S K Kauh ◽  
S T Ro ◽  
J Lee
Keyword(s):  
Feedback Control ◽  
Oxygen Sensor ◽  
Fuel Injection ◽  
Control Method ◽  
Modulation Method ◽  
Control Logic ◽  
Fuel Ratio ◽  
Switch Type ◽  
Three Way Catalyst ◽  
Ramp Control

The jump—ramp control algorithm has been widely adopted for the air—fuel ratio control in a fuel injection spark ignition (SI) engine by using a conventional on—off type oxygen sensor. But the jump—ramp control method has limitations in improving the frequency and amplitude of the air—fuel ratio oscillation. This study suggests a new feedback control logic called modulated fuel feedback control, which has a concept of pretuned air—fuel ratio oscillation. In the modulation method, the oxygen sensor output is not treated as on—off but as an analogue for feedback. By using the modulation method, the frequency and amplitude of the air—fuel ratio oscillation can be controllable to some extent to improve the conversion efficiency of a three-way catalyst. The results show that the performance of the modulation method is better than that of the jump—ramp control method in reducing the amplitude of the air—fuel ratio oscillation as well as in increasing the frequency of the air—fuel ratio oscillation.

Physics-based linear model predictive control strategy for three-way catalyst air/fuel ratio control

2021 ◽  
pp. 095440702110212
Author(s):  
Abdullah-al Mamun ◽  
Qilun Zhu ◽  
Mark Hoffman ◽  
Simona Onori
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Nonlinear Model ◽  
Computational Effort ◽  
Oxygen Storage ◽  
Pid Controllers ◽  
Storage Model ◽  
Fuel Ratio ◽  
Vehicle Test ◽  
Three Way Catalyst

The Current practice of air-fuel ratio control relies on empirical models and traditional PID controllers, which require extensive calibration to maintain the post-catalyst air-fuel ratio close to stoichiometry. In contrast, this work utilizes a physics-based Three-Way Catalyst (TWC) model to develop a model predictive control (MPC) strategy for air-fuel ratio control based on internal TWC oxygen storage dynamics. In this paper, parameters of the physics-based temperature and oxygen storage models of the TWC are identified using vehicle test data for a catalyst aged to 150,000 miles. A linearized oxygen storage model is then developed from the identified nonlinear model, which is shown via simulation to follow the nonlinear model with minimal error during nominal operation. This motivates the development of a Linear MPC (LMPC) framework using the linearized TWC oxygen storage model, reducing the requisite computational effort relative to a nonlinear MPC strategy. In this work, the LMPC utilizing a linearized physics-based TWC model is proven suitable for tracking a desired oxygen storage level by controlling the commanded engine air-fuel ratio, which is also a novel contribution. The offline simulation results show successful tracking performance of the developed LMPC framework.

scholarly journals The Effects of Use of the Range Extender in a Small Commercial Electric Vehicle

2020 ◽  
Vol 4 (1) ◽  
pp. 5-19
Author(s):  
Marcin Noga ◽  
Paweł Gorczyca ◽  
Radosław Hebda
Keyword(s):  
Electric Vehicle ◽  
Conversion Efficiency ◽  
Exhaust System ◽  
Spark Ignition Engine ◽  
Maximum Output ◽  
Fuel Conversion ◽  
Efficient Operation ◽  
Fuel Ratio ◽  
Range Extender ◽  
Three Way Catalyst

Research on the effects of the use of the range extender developed for a small commercial electric vehicle was presented in this paper. The range extender has a maximum output power of 2.65 kW. The developed auxiliary power unit consists of a three-phase generator propelled by an industrial low-power spark-ignition engine. The exhaust system was improved using a more efficient muffler. The implemented motorcycle muffler has a three-way catalyst (TWC) integrated inside. The use of the more advanced exhaust system aimed at reducing noise and exhaust emissions of the range extender. The efficient operation of the three-way catalytic converter requires a stoichiometric air-fuel ratio. To enable desired air-fuel ratio a fuel system was modified. In the first stage of research, the effects of improvements of the exhaust system on the range extender noise emissions were quantified. The next step covered the research of the fuel conversion efficiency, the exhaust gas composition, and the efficiency of conversion of the three-way catalyst. A significant decrease of noise and toxic gas emissions and an increase in the fuel conversion efficiency were revealed. The mentioned research was conducted in stationary conditions. After that, in the final part research of the running vehicle with the range extender on was made. The beneficial outcome of these tests enabled the development of a set of rules of the control of the range extender.

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