Extremum seeking-based optimal EGR set-point design for combustion engines in lean-burn mode

2021 ◽  
Author(s):  
Haoyun Shi ◽  
Yahui Zhang ◽  
Tielong Shen
Keyword(s):  
Extremum Seeking ◽  
Combustion Engines ◽  
Lean Burn ◽  
Set Point

A phenomenological model for the description of unburned hydrocarbons emission in ultra-lean engines

2021 ◽  
pp. 146808742110050
Author(s):  
Enrica Malfi ◽  
Vincenzo De Bellis ◽  
Fabio Bozza ◽  
Alberto Cafari ◽  
Gennaro Caputo ◽  
...  
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Pollutant Emissions ◽  
Average Error ◽  
Combustion Engines ◽  
Nitric Oxides ◽  
Lean Burn ◽  
Fuel Charge ◽  
Unburned Hydrocarbons ◽  
Model Reliability

The adoption of lean-burn concepts for internal combustion engines working with a homogenous air/fuel charge is under development as a path to simultaneously improve thermal efficiency, fuel consumption, nitric oxides, and carbon monoxide emissions. This technology may lead to a relevant emission of unburned hydrocarbons (uHC) compared to a stoichiometric engine. The uHC sources are various and the relative importance varies according to fuel characteristics, engine operating point, and some geometrical details of the combustion chamber. This concern becomes even more relevant in the case of engines supplied with natural gas since the methane has a global warming potential much greater than the other major pollutant emissions. In this work, a simulation model describing the main mechanisms for uHC formation is proposed. The model describes uHC production from crevices and flame wall quenching, also considering the post-oxidation. The uHC model is implemented in commercial software (GT-Power) under the form of “user routine”. It is validated with reference to two large bore engines, whose bores are 31 and 46 cm (engines named accordingly W31 and W46). Both engines are fueled with natural gas and operated with lean mixtures (λ > 2), but with different ignition modalities (pre-chamber device or dual fuel mode). The engines under study are preliminarily schematized in the 1D simulation tool. The consistency of 1D engine schematizations is verified against the experimental data of BMEP, air flow rate, and turbocharger rotational speed over a load sweep. Then, the uHC model is validated against the engine-out measurements. The averaged uHC predictions highlight an average error of 7% and 10 % for W31 and W46 engines, respectively. The uHC model reliability is evidenced by the lack of need for a case-dependent adjustment of its tuning constants, also in presence of relevant variations of both engine load and ring pack design.

Combination of extremum-seeking algorithms with effective hydraulic handling of equalization tanks to control anaerobic digesters

2010 ◽  
Vol 61 (11) ◽  
pp. 2825-2834 ◽  
Author(s):  
J. Alferes ◽  
I. Irizar
Keyword(s):  
Methane Production ◽  
Wastewater Treatment Plants ◽  
The State ◽  
Extremum Seeking ◽  
Limit Set ◽  
Anaerobic Digesters ◽  
Set Point ◽  
Control Approach ◽  
Upper Limit ◽  
Equalization Tank

The benefits of upgrading extremum-seeking controllers with an effective exploitation of the buffer capacity of equalization tanks have been investigated and applied to anaerobic digesters. In this respect, a Fuzzy-based supervisory module that monitors the state of the equalization tank has been designed and built on top of an extremum-seeking algorithm in charge of automatically regulating the wastewater fed into the anaerobic digester. The extremum-seeking controller guarantees good disturbance rejection and methane production around an upper limit set-point. The on-top Fuzzy module optimizes the long-term methane production by modifying this upper limit set-point as a function of the state of the equalization tank. A systematic simulation study has been carried out to evaluate the performance of the proposed control solution. Thus, on the basis of existing simulation benchmarks for assessment of control strategies in wastewater treatment plants, a dedicated simulation protocol for anaerobic digesters has been defined and implemented. Simulation results have shown that, compared with manual operation, effluent quality and methane production improvements of 10–15% are achieved using the proposed control approach.

Effect of Engine Variables on Combustion Performance of Lean Burn Spark Ignition Engine: An Overview

2002 ◽  
Author(s):  
A. Manivannan ◽  
R. Ramprabhu
Keyword(s):  
Internal Combustion Engines ◽  
Flow Characteristics ◽  
Exhaust Emissions ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Combustion Stability ◽  
Combustion Engines ◽  
Si Engine ◽  
Lean Burn ◽  
Lean Combustion

In the development of internal combustion engines, there has been a continuous effort to reduce fuel consumption and exhaust emissions. Lean combustion is a preferred concept for reducing exhaust emissions for meeting stringent emission standards. However lean combustion is associated with increased cycle-by-cycle combustion variation due to combustion instability. The combustion stability under lean mixture conditions could be improved through enhancement of flow characteristics. Effect of engine variables on lean combustion of Spark Ignition (SI) engine is presented, including combustion chamber and inlet port configuration, and ignition system. Use of pre-chamber for lean combustion is one of the feasible method to achieve stable ignition and quick flame propagation. This paper highlights and compares status of various research works carried out in the area of lean burn engines. A critical analysis of reported experimental data is presented in order to substantiate use of lean combustion in SI engine.

NOx Abatement in Exhaust from Lean-Burn Combustion Engines by Reduction of NO2 over Silver-Containing Zeolite Catalysts

1998 ◽  
Vol 37 (13-14) ◽  
pp. 1901-1903 ◽  
Author(s):  
Johan A. Martens ◽  
Anne Cauvel ◽  
Agna Francis ◽  
Chris Hermans ◽  
François Jayat ◽  
...  
Keyword(s):  
Zeolite Catalysts ◽  
Combustion Engines ◽  
Lean Burn ◽  
Nox Abatement

scholarly journals Lean-burn CNG engine with ignition chamber: from the idea to a running engine

2019 ◽  
Vol 176 (1) ◽  
pp. 3-9 ◽  
Author(s):  
Michael WEIßNER ◽  
Frank BEGER ◽  
Martin SCHÜTTENHELM ◽  
Gunesh TALLU
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
State Of The Art ◽  
Combustion Engines ◽  
Lean Burn ◽  
Compressed Natural Gas ◽  
Emission Regulations ◽  
Cng Engine ◽  
Funded Project ◽  
The Eu

Current and further developing CO2- and emission regulations worldwide and the competition to full electric mobility deliver a chal-lenge for internal combustion engines in general. A state of the art solution is the use of natural gas mainly contending methane to reduce CO2 significantly and to offer lowest emission levels. The EU-funded project GasOn developed engine concepts to fully exploit the advantages of CNG. This article describes the development of an innovative, monovalent engine dedicated to Compressed Natural Gas (CNG) and characterised by the lean burn concept and the innovative pre-chamber combustion.

Numerical Study to Achieve Stratified EGR in Engines

2002 ◽  
Author(s):  
Bassem H. Ramadan ◽  
Charles L. Gray ◽  
Harold J. Schock ◽  
Fakhri J. Hamady ◽  
Karl H. Hellman
Keyword(s):  
Numerical Study ◽  
Direct Injection ◽  
Fuel Mixture ◽  
Combustion Engines ◽  
Lean Burn ◽  
Complete Combustion ◽  
Stratified Charge ◽  
Automotive Emissions ◽  
Si Engines ◽  
Inlet Manifold

Exhaust Gas Re-circulation (EGR) has been used in intemal combustion engines to control automotive emissions. EGR is usually used to dilute the inlet charge, which consists of air, by redirecting part of the exhaust into the inlet manifold of the engine. This results in a reduction of the oxygen mass fraction in the inlet charge. However, dilution of the air-fuel mixture in an engine using stratified EGR could offer significant fuel economy saving comparable to lean burn or stratified charge direct-injection SI engines. The most critical challenge is to keep the EGR and air-fuel mixture separated, or to minimize the mixing between the two zones to an acceptable level for stable and complete combustion. Swirl-type stratified EGR and fuel-air flow structure is considered desirable for this purpose, because the circular shape of the cylinder tends to preserve the swirl motion. Moreover, the axial piston motion has minimal effect on the swirling motion of the fluid in the cylinder. In this study, we consider intake system design in order to generate a two-zone combustion system, where EGR is maintained in a layer on the periphery of the cylinder, and the fuel-air mixture is maintained in the center of the cylinder. KIVA-3V was used to perform numerical simulations on different EGR systems. The simulations were performed to determine if the two-zones can be generated in the cylinder, and to what extent mixing between the two zones occurs. For the engine geometries considered in this study, the results showed that it is possible to generate the two zones, but mixing is difficult to control.

Study of YSZ Amperometric Oxygen Sensor with a Dense Barrier Layer

2007 ◽  
Vol 280-283 ◽  
pp. 431-434 ◽  
Author(s):  
Xing Shi ◽  
Yue Zhang
Keyword(s):  
Diffusion Barrier ◽  
Internal Combustion Engines ◽  
Oxygen Sensor ◽  
Composite Electrode ◽  
Low Cost ◽  
Limiting Current ◽  
Combustion Engines ◽  
Lean Burn ◽  
New Type ◽  
And Diffusion

A new type of amperometric oxygen sensor was developed by an approach of co-pressing and co-sintering YSZ solid electrolyte. A dense LSM+YSZ composite electrode which was used as both cathode and diffusion barrier. Pre-sintered composite and YSZ powders were dry-pressed together to form a sheet with dual-layer of LSM+YSZ/YSZ. The sheet was then sintered at 1450°C. The anode was made of Pt paste, which was printed on to the other side of YSZ. The experiment results showed that the oxygen sensor exhibited a quite low operating temperature. At 400°C, the limiting current appeared in the voltage from 0.7 to 1.2V and the limiting current was a good linear relationship with the oxygen concentration up to 10 %. The sensor has some excellent features such as a rapid response, no reference gas, simple configuration and low cost. Taken together with the chemical stability of the diffusion barrier, the sensor is suitable for the control of air-to-fuel ratio in lean-burn internal combustion engines.

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