Real-time capable simulation of diesel combustion processes for HiL applications

2017 ◽  
Vol 19 (2) ◽  
pp. 214-229 ◽  
Author(s):  
Daniel Neumann ◽  
Christian Jörg ◽  
Nils Peschke ◽  
Joschka Schaub ◽  
Thorsten Schnorbus
Keyword(s):  
Heat Release ◽  
Real Time ◽  
Fuel Injection ◽  
Combustion Process ◽  
Boost Pressure ◽  
Diesel Combustion ◽  
Main Challenge ◽  
Combustion Properties ◽  
Input Variables ◽  
Improved Model

The complexity of the development processes for advanced diesel engines has significantly increased during the last decades. A further increase is to be expected, due to more restrictive emission legislations and new certification cycles. This trend leads to a higher time exposure at engine test benches, thus resulting in higher costs. To counter this problem, virtual engine development strategies are being increasingly used. To calibrate the complete powertrain and various driving situations, model in the loop and hardware in the loop concepts have become more important. The main effort in this context is the development of very accurate but also real-time capable engine models. Besides the correct modeling of ambient condition and driver behavior, the simulation of the combustion process is a major objective. The main challenge of modeling a diesel combustion process is the description of mixture formation, self-ignition and combustion as precisely as possible. For this purpose, this article introduces a novel combustion simulation approach that is capable of predicting various combustion properties of a diesel process. This includes the calculation of crank angle resolved combustion traces, such as heat release and other thermodynamic in-cylinder states. Furthermore, various combustion characteristics, such as combustion phasing, maximum gradients and engine-out temperature, are available as simulation output. All calculations are based on a physical zero-dimensional heat release model. The resulting reduction of the calibration effort and the improved model robustness are the major benefits in comparison to conventional data-driven combustion models. The calibration parameters directly refer to geometric and thermodynamic properties of a given engine configuration. Main input variables to the model are the fuel injection profile and air path–related states such as exhaust gas recirculation rate and boost pressure. Thus, multiple injection event strategies or novel air path control structures for future engine control concepts can be analyzed.

Semi-Premixed Diesel Combustion with Twin Peak Shaped Heat Release Using Two-Stage Fuel Injection

2016 ◽  
Author(s):  
Hideyuki Ogawa ◽  
Gen Shibata ◽  
Yuhei Sakane ◽  
Tatsuaki Arisawa ◽  
Tatstunori Obe
Keyword(s):  
Heat Release ◽  
Fuel Injection ◽  
Diesel Combustion ◽  
Two Stage ◽  
Twin Peak

A Study on the Calculation of Heat Release Rate to Compensate the Error Due to Single Zone Assumption in Diesel Engine

2005 ◽  
Author(s):  
Seung Hyup Ryu ◽  
Ki Doo Kim ◽  
Wook Hyeon Yoon ◽  
Ji Soo Ha
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Computational Analysis ◽  
Combustion Process ◽  
Operating Conditions ◽  
Zone Model ◽  
Specific Heats ◽  
Start Of Injection ◽  
Release Analysis ◽  
Improved Model

Accurate heat release analysis based on the cylinder pressure trace is important for evaluating combustion process of diesel engines. However, traditional single-zone heat release models (SZM) have significant limitations due mainly to their simplified assumptions of uniform charge and homogeneity while neglecting local temperature distribution inside cylinder during combustion process. In this study, a heat release analysis based on single-zone model has been evaluated by comparison with computational analysis result using Fire-code, which is based on multi-dimensional model (MDM). The limitations of the single-zone assumption have been estimated. To overcome these limitations, an improved model that includes the effects of spatial non-uniformity has been applied. From this improved single-zone heat release model (Improved-SZM), two effective values of specific heats ratios, denoted by γV and γH in this study, have been introduced. These values are formulated as the function of charge temperature changing rate and overall equivalence ratio by matching the results of the single-zone analysis to those of computational analysis using Fire-code about medium speed marine diesel engine. Also, it is applied that each equation of γV and γH has respectively different slopes according to several meaningful regions such as the start of injection, the end of injection, the maximum cylinder temperature, and the exhaust valve open. This calculation method based on improved single-zone model gives a good agreement with Fire-code results over the whole range of operating conditions.

scholarly journals Non-Chloride in Situ Preparation of Nano-Cuprous Oxide and Its Effect on Heat Resistance and Combustion Properties of Calcium Alginate

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1760 ◽  
Author(s):  
Peiyuan Shao ◽  
Peng Xu ◽  
Lei Zhang ◽  
Yun Xue ◽  
Xihui Zhao ◽  
...  
Keyword(s):  
Thermal Degradation ◽  
Heat Release ◽  
Hybrid Materials ◽  
Heat Release Rate ◽  
Release Rate ◽  
Cuprous Oxide ◽  
Calcium Alginate ◽  
Combustion Process ◽  
Protective Layer ◽  
Combustion Properties

With Cu2+ complexes as precursors, nano-cuprous oxide was prepared on a sodium alginate template excluded of Cl− and based on which the calcium alginate/nano-cuprous oxide hybrid materials were prepared by a Ca2+ crosslinking and freeze-drying process. The thermal degradation and combustion behavior of the materials were studied by related characterization techniques using pure calcium alginate as a comparison. The results show that the weight loss rate, heat release rate, peak heat release rate, total heat release rate and specific extinction area of the hybrid materials were remarkably lower than pure calcium alginate, and the flame-retardant performance was significantly improved. The experimental data indicates that nano-cuprous oxide formed a dense protective layer of copper oxide, calcium carbonate and carbon by lowering the initial degradation temperature of the polysaccharide chain during thermal degradation and catalytically dehydrating to char in the combustion process, and thereby can isolate combustible gases, increase carbon residual rates, and notably reduce heat release and smoke evacuation.

scholarly journals Influence of Fuel Injection, Turbocharging and EGR Systems Control on Combustion Parameters in an Automotive Diesel Engine

2019 ◽  
Vol 9 (3) ◽  
pp. 484 ◽  
Author(s):  
Giorgio Zamboni
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Alternative Fuels ◽  
Fuel Injection ◽  
Combustion Process ◽  
Environmental Parameters ◽  
Operating Conditions ◽  
Combustion Noise ◽  
First Derivative ◽  
Test Sets

Indicated pressure diagrams were measured during experimental campaigns on the control of fuel injection, turbocharging and hybrid exhaust gas recirculation systems in an automotive downsized diesel engine. Three-part load operating conditions were selected for four test sets, where strategies aimed at the reduction of NOX emissions and fuel consumption, limiting penalties in soot emissions and combustion noise were applied to the selected systems. Processing of in-cylinder pressure signal, its first derivative and curves of the rate of heat release allowed us to evaluate seven parameters related to the combustion centre and duration, maximum values of pressure, heat release and its first derivative, heat released in the premixed phase and a combustion noise indicator. Relationships between these quantities and engine operating, energy and environmental parameters were then obtained by referring to the four test sets. In the paper, the most significant links are presented and discussed, aiming at a better understanding of the influence of control variables on the combustion process and the effects on engine behaviour. The proposed methodology proved to be a consistent tool for this analysis, useful for supporting the application of alternative fuels or advanced combustion modes.

In-Cycle Closed Loop Control of the Fuel Injection on a 1-Cylinder Heavy Duty CI-Engine

2010 ◽  
Author(s):  
Claes-Go¨ran Zander ◽  
Per Tunesta˚l ◽  
Ola Stenla˚a˚s ◽  
Bengt Johansson
Keyword(s):  
Heat Release ◽  
Real Time ◽  
Fuel Injection ◽  
Real Time Control ◽  
Loop Control ◽  
Time Control ◽  
Ci Engine ◽  
The Difference ◽  
Proportional Controller ◽  
Polytropic Exponent

The focus of this article is on implementation of real time combustion control by using an FPGA. The feedback used for the controller is the heat release. Due to the desire to avoid using division on the FPGA an alternative way of calculating the polytropic exponent is investigated. When this method is compared against using a constant exponent it shows less fluctuations in regards to cycle to cycle variations when calculating the heat release. A dual injection strategy is used and real time control is implemented on the second fuel injection. The calculated heat release is continuously compared with a reference and then the difference is converted to a duration correction of the fuel injection. This is done by a proportional controller which is initiated after the start of the second injection. By adding a perturbation on the first fuel injection the controller is shown to compensate during the second and thereby decreasing the cycle to cycle variations.

Mechanism of thermal efficiency improvement in twin shaped semi-premixed diesel combustion

2021 ◽  
pp. 146808742110264
Author(s):  
Kazuki Inaba ◽  
Yanhe Zhang ◽  
Yoshimitsu Kobashi ◽  
Gen Shibata ◽  
Hideyuki Ogawa
Keyword(s):  
Heat Release ◽  
Thermal Efficiency ◽  
Gas Flow ◽  
Fuel Injection ◽  
Premixed Combustion ◽  
Combustion Noise ◽  
Diesel Combustion ◽  
Combustion Mode ◽  
Secondary Stage ◽  
Combustion Phase

Improvements of the thermal efficiency in twin shaped semi-premixed diesel combustion mode with premixed combustion in the primary stage and spray diffusive combustion in the secondary stage with multi-stage fuel injection were investigated with experiments and 3D-CFD analysis. For a better understanding of the advantages of this combustion mode, the results were compared with conventional diesel combustion modes, mainly consisting of diffusive combustion. The semi-premixed mode has a higher thermal efficiency than the conventional mode at both the low and medium load conditions examined here. The heat release in the semi-premixed mode is more concentrated at the top dead center, resulting in a significant reduction in the exhaust loss. The increase in the cooling loss is suppressed to a level similar to the conventional mode. In the conventional mode the rate of heat release becomes more rapid and the combustion noise increases with advances in the combustion phase as the premixed combustion with pilot and pre injections and the diffusive combustion with the main combustion occurs simultaneously. In the semi-premixed mode, the premixed combustion with pilot and primary injections and the diffusive combustion with the secondary injection occurs separately in different phases, maintaining a gentler heat release with advances in the combustion phase. The mechanism of the cooling loss suppression with the semi-premixed mode at low load was investigated with 3D-CFD. In the semi-premixed mode, there is a reduction in the gas flow and quantity of the combustion gas near the piston wall due to the suppression of spray penetration and splitting of the injection, resulting in a smaller heat flux.

scholarly journals Investigating Combustion Process of N-Butanol-Diesel Blends in a Diesel Engine with Variable Compression Ratio

2021 ◽  
Vol 3 (3) ◽  
pp. 618-628
Author(s):  
György Szabados ◽  
Kristóf Lukács ◽  
Ákos Bereczky
Keyword(s):  
Heat Release ◽  
Heat Release Rate ◽  
Compression Ratio ◽  
Release Rate ◽  
Ignition Delay ◽  
Alternative Fuels ◽  
Internal Combustion Engines ◽  
Combustion Process ◽  
Injection Angle ◽  
Combustion Properties

The search for alternative fuels for internal combustion engines is ongoing. Among the alternatives, plant-based fuels can also be mentioned. Alcohol is not a common fuel for diesel engines because the physical and chemical properties of the alcohols are closer to those of gasoline. In our research, the combustion properties of diesel-n-butanol mixtures have been investigated to obtain results on the effect of butanol blending on combustion. Among the combustion properties, ignition delay, in-cylinder pressure, and heat release rate can be mentioned. They have been observed under different compression conditions on an engine on which the compression ratio can be adjusted. The method used was a quite simple one, so the speed of the engine was set to a constant 900 rpm without load, while three compression ratios (19.92, 15.27, and 12.53) were adjusted with a fuel flow rate of 13 mL/min and the pre-injection angle of 18° BTDC. Blending butanol into the investigated fuel does not significantly affect maximal values of indicated pressure, while much more effect on the pressure rising rate can be detected. Furthermore, heat release rate and ignition delay increased at every compression ratio investigated. Despite the low blending rates of butanol in the mixtures, butanol significantly affects the combustion parameters, especially at high compression ratios.

Researches Regarding the Use of Bioethanol at the Supercharged Spark Ignition Engine

2014 ◽  
Vol 659 ◽  
pp. 217-222
Author(s):  
Zuhair H. Obeid Obeid ◽  
Constantin Pana ◽  
Niculae Negurescu ◽  
Alexandru Cernat
Keyword(s):  
Combustion Velocity ◽  
Combustion Process ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Theoretical Research ◽  
Experimental Investigations ◽  
Boost Pressure ◽  
Local Cooling ◽  
Combustion Properties ◽  
Si Engines

The general objective of the researches is use of bioethanol at the supercharged spark ignition engine for improving engine efficiency, improving performance of power and torque and decreasing of the emissions level. Bioethanol is a very good alternative fuel for supercharged SI engines because of its better combustion proprieties comparative to the gasoline; it has a higher combustion velocity, a high resistance to the combustion with knock and can be used and as a cooling agent of the intake air. By achieving these specific objectives this paper brings important contributions to improvement the SI engines performance. The paper presents results of some theoretical and experimental investigations on a 1.5 L supercharged SI engine fuelled with gasoline-bioethanol blends. At the theoretical research, the physical – mathematical model uses a Vibe combustion formal law and for combustion with knock avoiding the combustion duration is established shorter than end-gas auto ignition delay evaluated by Douaud and Evzat equation. Is established an optimum correlation between the engine air boost pressure, spark ignition timing, dosage, air boost temperature and energetic performance for to the avoiding of knocking phenomena. The theoretical and experimental investigations show that the improvement of the combustion process by use the bioethanol at the supercharged spark ignition engine leads to the reduction of BSFC (with 5% at the stoichiometric dosage), to the accentuated reduction CO and HC (with 5% and 13% respectively at the same dosage), due to a lower C content and better combustion properties of the bioethanol. In same time, the NOx emissions level significantly decreases (with 7% at the same dosage) because of the local cooling effect produced by bioethanol vaporization.

scholarly journals COMPARISON OF COMBUSTION INDICATORS OF TWO-STROKE ENGINES WITH A CARBURETOR AND DIRECT FUEL INJECTION

2021 ◽  
pp. 35-44
Author(s):  
V.A. Korohodskyi
Keyword(s):  
Heat Release ◽  
Fuel Injection ◽  
Combustion Process ◽  
Expansion Ratio ◽  
Mixture Formation ◽  
Load Characteristic ◽  
Combustion Pressure ◽  
Maximum Value ◽  
Characteristic Modes ◽  
Direct Fuel Injection

The subject matter of study in the article is the indicators of the combustion process of a two-stroke engine 1D 8.7 / 8.2 with spark ignition when using a carburetor power supply system (external mixture formation) and a direct fuel injection system (internal mixture formation). Internal mixture formation ensures the organization of a stratified fuel-air charge (SFAC) and a stratified lean fuel-air charge (SLFAC). Combustion indicators allow you to assess the nature of the combustion process. The goal is to determine the nature of the change in the combustion indicators of the engine with external and internal mixture formation during the organization of the working process with the SFAC and SLFAC at the load characteristic modes (n = 3,000 rpm). The tasks to be solved are as follows. The use of internal mixture formation and the organization of the combustion of SLFAC and SFAC made it possible to obtain values of ηi greater than with external mixture formation at all modes of the load characteristic. The maximum value of ηi for SLFAC is 0.5 at a load bmep = 0.2 MPa, for SFAC – 0.44 at bmep = 0.25 MPa and 0.3 at bmep = 0.36 MPa for an engine with a carburettor. Maximum combustion pressure (рz), pressure increase ratio (λ), preliminary expansion ratio (ρ), further expansion ratio (δ), combustion character indicator (m), maximum heat release rate (dx / dfi max), duration of combustion from TDC to point Z (φz), total duration of combustion (dφz); to construct the characteristics of changes in combustion indicators and to obtain empirical dependences depending on the engine load. An experimental-analytical research method is used, which provides for the determination of the nature and analysis of the course of the combustion process according to the combustion indicators established by the experimental indicator diagrams. The following results were obtained. The use of internal mixture formation and the organization of the combustion of SFAC and SLFAC made it possible to obtain ηi values greater than with external mixture formation at all modes of the load characteristic. The maximum value of ηi for SLFAC is 0.5 at a load ре = 0.2 MPa, for SFAC - 0.44 at ре = 0.25 MPa and 0.3 at ре = 0.36 MPa for an engine with a carburetor. The pressure in the cylinder with the piston position at TDC is on average 1.5 times higher for an engine with a carburetor, and the maximum combustion pressure рz is higher up to 11 % with the organization of SLFAC (the degree of pressure increase λ is reduced by 26 %) and 20-22 % higher than in the organization of SFAC (the value of λ is reduced by 31 %). An increase in the compression ratio ε by 26.4 % and a decrease in the degree of preliminary expansion ρ at SLFAC in comparison with SFAC made it possible to increase the degree of further expansion δ by an average of 30 % and by 43 % in comparison with the carburetor power system. When organizing SLFAC, the value of the indicator of the nature of combustion m is, on average, 1.4 times higher than that of an engine with a carburetor and 1.45 times higher relative to the organization of SFAC, at which the maximum rate of heat release dx / dfi max is up to 40 % higher than in the engine with carburetor. The SLFAC organization allowed reduce the combustion duration by 39 % relative to external mixture formation and by 36 % relative to the SFAC organization. Conclusions. The scientific novelty of the results obtained consists in obtaining data and empirical dependences of the indicators of the combustion process of the 1D 8.7 / 8.2 engine with external and internal mixture formation with the organization of SFAC and SLFAC at load characteristic modes (n = 3,000 rpm). It was found that the best technical, economic and environmental indicators correspond to the organization of internal mixing with SLFAC.

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