Set-Point Adaptation Strategy of Air Systems of Light-Duty Diesel Engines for NOx Emission Reduction Under Acceleration Conditions

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Kyunghan Min ◽  
Haksu Kim ◽  
Manbae Han ◽  
Myoungho Sunwoo
Keyword(s):  
Diesel Engines ◽  
Performance Optimization ◽  
Control Structure ◽  
Engine Performance ◽  
Optimization Method ◽  
Driving Cycle ◽  
Operating Conditions ◽  
Nox Emission ◽  
Exhaust Gas ◽  
Set Point

Modern diesel engines equip the exhaust gas recirculation (EGR) system because it can suppress NOx emissions effectively. However, since a large amount of exhaust gas might cause the degradation of drivability, the control strategy of EGR system is crucial. The conventional control structure of the EGR system uses the mass air flow (MAF) as a control indicator, and its set-point is determined from the well-calibrated look-up table (LUT). However, this control structure cannot guarantee the optimal engine performance during acceleration operating conditions because the MAF set-point is calibrated at steady operating conditions. In order to optimize the engine performance with regard to NOx emission and drivability, an optimization algorithm in a function of the intake oxygen fraction (IOF) is proposed because the IOF directly affects the combustion and engine emissions. Using the NOx and drivability models, the cost function for the performance optimization is designed and the optimal value of the IOF is determined. Then, the MAF set-point is adjusted to trace the optimal IOF under engine acceleration conditions. The proposed algorithm is validated through scheduled engine speeds and loads to simulate the extra-urban driving cycle of the European driving cycle. As validation results, the MAF is controlled to trace the optimal IOF from the optimization method. Consequently, the NOx emission is substantially reduced during acceleration operating conditions without the degradation of drivability.

scholarly journals Research on the Energy Efficiency Indicators of Transport Diesel Engines under Transient Operation Conditions

Pomorstvo ◽  
2018 ◽  
Vol 32 (2) ◽  
pp. 228-238 ◽  
Author(s):  
Sergejus LebedevasPaulius ◽  
Paulius Rapalis ◽  
Rima Mickevicienė
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Engine Performance ◽  
Mechanical Efficiency ◽  
Operating Conditions ◽  
Efficiency Coefficient ◽  
Operation Conditions ◽  
Power Increase ◽  
Control Units ◽  
Additional Equipment

In this study, we have investigated the efficiency of transport diesel engines CAT3512B-HD in transient braking and acceleration modes in 2M62M locomotives. A comparative analysis of the diesel engine performance has been performed at speeds of power increase and braking ranging from 4–5 kW/s to 17–18 kW/s. A decrease in the fuel economy occurred, and the main reason for it (compared with the steady-state operating condition at qcycl = idem) has been found to be the deterioration of the mechanical efficiency coefficient due to the loss of the additional equipment kinetic energy of the engine. The efficiency decreased by 3–3.5% under power increase operations and by 10–14% in the braking modes. The original methodology for the evaluation of the diesel engine parameters registered by the engine control units (ECU) in the engine operating conditions, mathematical modelling application AVL BOOST, and analytical summaries in artificial neural networks (ANNs) have been used. The errors in the obtained results have been 5–8% at a determination coefficient of 0.97–0.99.

Parametric Study of the Scavenging Process in Marine Two-Stroke Diesel Engines

2015 ◽  
Author(s):  
Fredrik Herland Andersen ◽  
Stefan Mayer
Keyword(s):  
Diesel Engines ◽  
Vortex Breakdown ◽  
Initial Conditions ◽  
Combustion Process ◽  
Operating Conditions ◽  
Exhaust Valve ◽  
Delivery Ratio ◽  
Exhaust Gas ◽  
Scale Production ◽  
Cfd Model

Large commercial ships such as container vessels and bulk carriers are propelled by low-speed, uniflow scavenged two-stroke diesel engines. The integral in-cylinder process in this type of engine is the scavenging process, where the burned gas from the combustion process is evacuated through the exhaust valve and replaced with fresh air for the subsequent compression stroke. The scavenging air enters the cylinder via inlet ports which are uncovered by the piston at bottom dead center (BDC). The exhaust gas is then displaced by the fresh air. The scavenging ports are angled to introduce a swirling component to the flow. The in-cylinder swirl is beneficial for air-fuel mixture, cooling of the cylinder liner and minimizing dead zones where pockets of exhaust gas are trapped. However, a known characteristic of swirling flows is an adverse pressure gradient in the center of the flow, which might lead to a local deficit in axial velocity and the formation of central recirculation zones, known as vortex breakdown. This paper will present a CFD analysis of the scavenging process in a MAN B&W two-stroke diesel engine. The study include a parameter sweep where the operating conditions such as air amount, port timing and scavenging pressure are varied. The CFD model comprise the full geometry from scavenge receiver to exhaust receiver. Asymmetric inlet and outlet conditions is included as well as the dynamics of a moving piston and valve. Time resolved boundary conditions corresponding to measurements from an operating, full scale production, engine as well as realistic initial conditions are used in the simulations. The CFD model provides a detailed description of the in-cylinder flow from exhaust valve opening (EVO) to exhaust valve closing (EVC). The study reveals a close coupling between the volume flow (delivery ratio) and the in-cylinder bulk purity of air which appears to be independent of operating conditions, rpm, scavenge air pressure, BMEP etc. The bulk purity of air in the cylinder shows good agreement with a simple theoretical perfect displacement model.

Design and Development of Surge Tank for NOx Emission Reduction in B20 Biofueled Diesel Engine

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Jaspreet Hira ◽  
Basant Singh Sikarwar ◽  
Rohit Sharma ◽  
Vikas Kumar ◽  
Prakhar Sharma
Keyword(s):  
Diesel Engine ◽  
Research Work ◽  
Engine Performance ◽  
Nox Emission ◽  
Intake Manifold ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Surge Tank ◽  
Brake Thermal Efficiency ◽  
Exhaust Gas Temperature

In this research work, a surge tank is developed and utilised in the diesel engine for controlling the NOX emission. This surge tank acts as a damper for fluctuations caused by exhaust gases and also an intercooler in reducing the exhaust gas temperature into the diesel engine intake manifold. With the utilisation of the surge tank, the NOX emission level has been reduced to approximately 50%. The developed surge tank is proved to be effective in maintaining the circulation of water at appropriate temperatures. A trade-off has been established between the engine performance parameters including the brake thermal efficiency, brake specific fuel consumption, exhaust gas temperature and all emission parameters including HC and CO.

scholarly journals Effect of Biodiesel B100 and Ethanol Blends on the Performance of Small Diesel Engine

2021 ◽  
Vol 2 (2) ◽  
pp. 101
Author(s):  
Alfian Firdiansyah ◽  
Nasrul Ilminnafik ◽  
Agus Triono ◽  
Muh Nurkoyim Kustanto
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Alternative Energy ◽  
High Efficiency ◽  
Engine Performance ◽  
Exhaust Gas ◽  
Calophyllum Inophyllum ◽  
Ethanol Blends ◽  
High Level ◽  
Test Fuel

<p class="02abstracttext"><span lang="IN">A small diesel engine is a machine that has high efficiency but causes a high level of pollution. The most widely used fuel so far is fossil energy which is unrenewable energy. The fruit of the Calophyllum inophyllum plant has great potential to be developed as alternative energy for small diesel engines. In this study, the test fuel used was D100, B100, E5, E10, and E15. The small engine diesel used TG-R180 Diesel with a compression ratio of 20:1 at engine turns 1500, 1800, 2100, and 2400 rpm, and the braking load at a constant prony disc brake is 1,5 kg/cm<sup>2</sup>. The result of the study using E10 fuel can improve engine performance and can reduce the opacity of the exhaust gas. The highest power in the D100 fuel at 2100 rpm is 8,06 PS. The highest thermal efficiency of E10 fuel is 50,29%. The use of Calophyllum inophyllum biodiesel (B100) can reduce exhaust gas opacity in small diesel engines when compared to the use of D100. E10 fuel has the lowest exhaust gas opacity rate of 4,1%.</span></p>

scholarly journals Modeling of power and torque curves of a diesel at the design stage

2019 ◽  
Vol 126 ◽  
pp. 00052
Author(s):  
Alexander Gots ◽  
Vladimir Klevtsov ◽  
Alexander Lyukhter
Keyword(s):  
Diesel Engines ◽  
Test Bench ◽  
Extreme Values ◽  
Engine Performance ◽  
Operating Conditions ◽  
Design Stage ◽  
Maximum Torque ◽  
Exhaust Gases ◽  
Upper Limit ◽  
Specific Speed

An external speed characteristics outlines the upper limit of the field of possible operating conditions of the engine. With its help, therefore, it is possible to judge the extreme values of the indicators and parameters of the engine when it is running at a specific speed of the crankshaft. It is at theexternal speed characteristics of the engine parts are subjected to the greatest mechanical and thermalloads, the maximum is also the smoke of the exhaust gases of diesel engines. This indicates the particular importance of techniques that allow to determine the performance of the engine in the modes of external speed characteristics. Get external speed characteristics when testing the engine on the test bench. However, this possibility is not always available, especially it is not at the design stage. When calculating the cycle, the engine performance is obtained in two modes – rated power and maximum torque. Therefore, the external speed characteristics, built by calculation is important at the stage of justification of the main indicators and parameters of the designed engine.

Control-Oriented Model Development and Experimental Validation for a Modern Diesel Engine

2020 ◽  
Author(s):  
Kuo Yang ◽  
Pingen Chen
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Model Development ◽  
Engine Performance ◽  
Operating Conditions ◽  
Least Square ◽  
Injection Timing ◽  
Model Based ◽  
Wide Range ◽  
Mean Square Errors

Abstract Modern Diesel engines have become highly complex multi-input multi-output systems. Controls of modern Diesel engines to meet various requirements such as high fuel efficiency and low NOx and particulate matter (PM) emissions, remain a great challenge for automotive control community. While model-based controls have demonstrated significant potentials in achieving high Diesel engine performance. Complete and high-fidelity control-oriented Diesel engine models are much needed as the foundations of model-based control system development. In this study, a semi-physical, mean-value control-oriented model of a turbocharged Diesel engine equipped with high-pressure exhaust gas recirculation (EGR) and variable geometry turbocharger (VGT) is developed and experimentally validated. The static calibration of Diesel engine model is achieved with the least-square optimization methodology using the experimental test data from a physical Diesel engine platform. The normalized root mean square errors (NRMSEs) of the calibration results are in the range of 0.1095 to 0.2582. The cross-validation results demonstrated that the model was capable of accurately capturing the engine torque output and NOx emissions with the control inputs of EGR, VGT and Start of Injection timing (SOI) in wide-range operating conditions.

NOx emissions in direct injection diesel engines: Part 2: model performance for conventional, prolonged ignition delay, and premixed charge compression ignition operating conditions

2017 ◽  
Vol 19 (5) ◽  
pp. 528-541 ◽  
Author(s):  
Clemens Brückner ◽  
Panagiotis Kyrtatos ◽  
Konstantinos Boulouchos
Keyword(s):  
Diesel Engines ◽  
Ignition Delay ◽  
Direct Injection ◽  
Operating Conditions ◽  
Premixed Combustion ◽  
Nox Emission ◽  
Nox Emissions ◽  
Nox Formation ◽  
Parameter Variations ◽  
And Diffusion

Investigations from recent years have shown that at operating conditions characterized by long ignition delays and resulting large proportions of premixed combustion, the NOx emission trend does not correspond to the (usually) postulated correlation with an appropriately defined (adiabatic) burnt flame temperature. This correlation, however, is the cornerstone of most published NOx models for direct injection diesel engines. In this light, a new phenomenological NOx model has been developed in Brückner et al. (Part 1), which considers NOx formation from products of premixed and diffusion combustion and accounts for compression heating of post-flame gases, and describes NOx formation by thermal chemistry. In this study (Part 2), the model is applied to predict NOx emissions from two medium-speed direct injection diesel engines of different size and at various operating conditions. Single parameter variations comprising sweeps of injection pressure, start of injection, load, exhaust gas recirculation rate, number of injections, and end-of-compression temperature are studied on a single-cylinder engine. In addition, different engine configurations (valve timing, turbocharger setup) and injection parameters of a marine diesel engine are investigated. For both engines and all parameter variations, the model prediction shows good agreement. Most notably, the model captures the turning point of the NOx emission trend with increasing ignition delay (first decreasing, then increasing NOx) for both engines. The differentiation in the physical treatment of the products of premixed and diffusion with increasing ignition delay showed to be essential for the model to capture the trend-reversal. Specifically, the model predicted that peak NOx formation rates in diffusion zones decrease with increasing ignition delay, whereas for the same change in ignition delay, peak formation rates in premixed zones increase. This is caused by the high energy release in short time, causing a strong compression of existing premixed combustion product zones that mix at a slower rate and have less time to mix, significantly increasing their temperature. In contrast, the model under-predicts NOx emissions for very low oxygen concentrations, in particular below 15 vol.%, which is attributed to the simple thermal NOx kinetic mechanism used. It is concluded that the new model is able to predict NOx emissions for conventional diesel combustion and for long ignition delay operating conditions, where a substantial amount of heat is released in premixed mode.

Turbocharging Systems With Control Intervention for Medium Speed Four-Stroke Diesel Engines

1989 ◽  
Vol 111 (3) ◽  
pp. 560-569 ◽  
Author(s):  
E. Meier ◽  
J. Czerwinski
Keyword(s):  
Diesel Engines ◽  
Engine Speed ◽  
Engine Performance ◽  
Exhaust Gas ◽  
Full Load ◽  
Medium Speed ◽  
Power Turbine ◽  
Control Intervention ◽  
Turbocharging System ◽  
Compressor Surge

The turbocharging systems of highly boosted four-stroke diesel engines (BMEP 25 bar/363 psi) have to cope with two basic problems: lack of air and compressor surge at reduced engine speed. In the case of medium speed engines for ship propulsion and stationary applications, the following three control interventions have proved to be successful solutions: (1) waste gating air or exhaust gas at full load and speed, (2) using a compounded or independent exhaust gas driven power turbine that can be shut off at part load and speed, and (3) blowing air from the compressor outlet to the turbine inlet through a controlled bypass. The effect of these control interventions on engine performance is shown by examples and analyzed by means of characteristic quantities for the efficiency of the turbocharging system and the engine. The definitions and meanings of these quantities are explained in the first part of the paper.

scholarly journals Influence of biodiesel blends produced in Colombia on a Diesel engine

2021 ◽  
Vol 15 (3) ◽  
pp. 8428-8439
Author(s):  
Oscar Venegas ◽  
Luisa Mónico
Keyword(s):  
Diesel Engines ◽  
Alternative Fuels ◽  
Engine Performance ◽  
Ease Of Use ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
The Past ◽  
Selection For ◽  
Vehicle Market ◽  
Palm Oil Biodiesel

Diesel engines have dominated the heavy duty and passenger vehicle market in the past 30 years. Consequently, the oil-derived fuels demand and the amount of pollutant emissions have witnessed exponential growth during the last three decades. Although Diesel engines present the advantage of higher efficiency and, therefore, lower levels of CO2 emissions,  they produce high levels of NOX and particulate matter. In order to face these difficulties, the use of alternative fuels started booming in the early 2000s and continue to gain influence today. Biodiesel stands out from the alternative fuels’ selection for its ease of use, production, storage and potential to reduce levels of particles, CO, HC and CO2. The main goal of this research is to experimentally determine the influence of palm oil biodiesel produced in Colombia on a Diesel engine’s behavior in terms of engine performance and pollutant emissions. As different mixtures of commercial Diesel and biodiesel at different operating conditions were tested, the results showed that it is possible to maintain the engine’s performance at acceptable levels and to, in some cases, reduce smoke density and NOX levels.

Multi-zone reaction-based modeling of combustion for multiple-injection diesel engines

2018 ◽  
Vol 21 (6) ◽  
pp. 1012-1025 ◽  
Author(s):  
Yifan Men ◽  
Ibrahim Haskara ◽  
Guoming Zhu
Keyword(s):  
Diesel Engines ◽  
Exhaust Gas Recirculation ◽  
Operating Conditions ◽  
Computational Time ◽  
Zone Model ◽  
Exhaust Gas ◽  
Cylinder Pressure ◽  
Multiple Injections ◽  
Burn Rate ◽  
Gas Recirculation

As the requirements for performance and restrictions on emissions become stringent, diesel engines are equipped with advanced air, fuel, exhaust gas recirculation techniques, and associated control strategies, making them incredibly complex systems. To enable model-based engine control, control-oriented combustion models, including Wiebe-based and single-zone reaction-based models, have been developed to predict engine burn rate or in-cylinder pressure. Despite model simplicity, they are not suitable for engines operating outside the normal range because of the large error beyond calibrated region with extremely high calibration effort. The purpose of this article is to obtain a parametric understanding of diesel combustion by developing a physics-based model which can predict the combustion metrics, such as in-cylinder pressure, burn rate, and indicated mean effective pressure accurately, over a wide range of operating conditions, especially with multiple injections. In the proposed model, it is assumed that engine cylinder is divided into three zones: a fuel zone, a reaction zone, and an unmixed zone. The formulation of reaction and unmixed zones is based on the reaction-based modeling methodology, where the interaction between them is governed by Fick’s law of diffusion. The fuel zone is formulated as a virtual zone, which only accounts for mass and heat transfer associated with fuel injection and evaporation. The model is validated using test data under different speed and load conditions, with multiple injections and exhaust gas recirculation rates. It is shown that the multi-zone model outperformed the single-zone model in in-cylinder pressure prediction and calibration effort with a mild penalty in computational time.

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