Mathematical Model of Diesel Engine Combustion Process: Part 1 — Theory

1997 ◽  
Author(s):  
Stanislav N. Danov ◽  
Ashwani K. Gupta
Keyword(s):  
Differential Equation ◽  
Mathematical Model ◽  
Diesel Engine ◽  
Differential Equations ◽  
Diffusion Flame ◽  
Fuel Injection ◽  
Diffusion Flames ◽  
Direct Injection ◽  
Combustion Process ◽  
And Diffusion

Abstract A mathematical model of combustion process in a diesel engine has been developed. The combustion process is considered to have both the premixed and diffusion flame. The combustion of fuel vaporized during the self-ignition delay period is modeled according to the conditions of premixed flame. A kinetic differential equation has been formulated for modeling this kind of combustion. The combustion of fuel during the injection process is modeled according to the theory of diffusion flames. This process is strongly influenced by processes of fuel injection, vaporization and diffusion. The atomization process is taken into account by means of the Sauter mean diameter (SMD) of fuel droplets. The instantaneous vaporization rate is defined by the current values of temperature, pressure, concentration of fuel vapors and the mean fuel droplet size in terms of the SMD. The mathematical model includes differential equations describing the processes of fuel injection, vaporization, heat transfer and combustion in both the premixed and diffusion flame that takes place in the engine cylinder. The above equations are solved together with the differential equation of the first law of thermodynamics expressing the energy conversion process in the cylinder of diesel engine. The fourth-order Runge-Kutta method is applied for obtaining numerical solution of the system of differential equations. The analysis is performed on a PC using FORTRAN 90. The results have been simulated for a marine direct injection (DI) diesel engine (Model Silzer 6RLB-66) having a cylinder bore diameter of 0.66 m, and stroke of 1.4 m. The amount of fuel used in this engine during the experiments is 0.03785 kg per cycle per cylinder. The numerical experiments have been carried out for the effect of duration of fuel injection and the beginning of fuel injection (expressed in terms of degrees of crank angle before TDC) on the subsequent combustion parameters and the integral indicator parameters of the engine.

Understanding of Diesel Engine Combustion Process via Mathematical Modeling: Part 2 — Results

1997 ◽  
Author(s):  
Stanislav N. Danov ◽  
Ashwani K. Gupta
Keyword(s):  
Diesel Engine ◽  
Diffusion Flame ◽  
Numerical Experiments ◽  
Fuel Injection ◽  
Combustion Process ◽  
Gas Mixture ◽  
Vaporization Rate ◽  
Atomization Process ◽  
And Diffusion ◽  
Integral Indicator

Abstract In the companion Part 1 of this two part series paper a mathematical model of combustion process in a diesel engine was presented having both premixed and diffusion flame. The combustion of fuel vaporized during the self-ignition delay period is modeled according to the conditions of premixed flame. A kinetic differential equation has been created for modeling this kind of combustion. The combustion of fuel during the injection process is modeled according to the theory of diffusion flames. This process is strongly influenced by processes of fuel injection, vaporization and diffusion. The atomization process is taken into account by means of the Sauter mean diameter (SMD) of fuel droplets. The instantaneous vaporization rate is defined by the current value of temperature, pressure, concentration of fuel vapors and the mean fuel droplet size in terms of the SMD. The mathematical model includes differential equations describing the processes of fuel injection, vaporization, heat transfer and combustion in both premixed and diffusion flame that occurs in the engine cylinder. The above equations are solved together with the differential equation of the first law of thermodynamics expressing the energy conversion process in the cylinder of diesel engine. The fourth-order Runge-Kutta method is applied for obtaining numerical solution of the system of differential equations. The model is calibrated and validated for two different turbocharged diesel engines — 8DKRN 74/160 and Sulzer-6RLB-66. The analysis is performed on a PC using FORTRAN 90. The comparison between the experimental data and numerical results shows very good agreement. Numerical experiments have been carried out for examining the combustion behavior in the cylinder of a marine DI diesel engine Sulzer 6RLB-66 having a cylinder diameter of 0.66 m bore and stroke of 1.4 m. The influence of the quality of fuel atomization process, estimated via the SMD, on the fuel vaporization rate and overall combustion rate has been evaluated. This influence is quantified and the results show very strong influence of SMD on the vaporization and combustion process, both with respect to the maximum rates and the duration of the processes. In addition numerical experiments have been carried out for determining the effect of duration of fuel injection and the beginning of fuel injection (degrees of crank angle rotation before TDC) on subsequent combustion parameters and integral indicator parameters of the engine. These results show that ratio: “amount of fuel burnt under the premixed flame conditions / amount of fuel burnt under diffusion flame conditions” for one cycle varies significantly with the change in fuel injection duration. The model provides both the instantaneous values of engine parameters in the cylinder (i.e., temperature, pressure, current air-gas mixture composition, heat transfer rate, thermo-physical properties of the air-gas mixture, etc.) and integral indicator engine parameters (mean indicated pressure, specific fuel consumption, efficiency, etc.). A comparison between experimental and modeling data show gratifying results.

Simulation Research on Post-Injection of Electronically Controlled Heavy-Duty Diesel Engine

2011 ◽  
Vol 121-126 ◽  
pp. 2238-2242
Author(s):  
Ming Hai Li ◽  
Feng Jiang ◽  
Biao Liu ◽  
Ming Gao Ouyang
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Pressure Rise ◽  
Injection System ◽  
Post Injection ◽  
Simulation Research ◽  
Di Diesel Engine ◽  
Heavy Duty Diesel

GT-Suite software is used to establish the simulation model of electronic fuel injection system for 16V280ZJ diesel engine. Combustion process simulation calculation is conducted to the direct injection (DI) diesel engine based on a main-post double injection scheme. Simulation parameters are modified based on the comparison with given experimental results. The calculation results effectively reflect the influence of fuel ratio and the interval angle between main and post injection over emission and fuel economy. Finally, in order to improve the engine emissions and reduce the pressure rise rate, we get the optimal injection solution for the main-post injection mode.

1D Engine Simulation of a Small HSDI Diesel Engine Applying a Predictive Combustion Model

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
T. Cerri ◽  
A. Onorati ◽  
E. Mattarelli
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Combustion Model ◽  
Full Load ◽  
Partial Load

The paper analyzes the operations of a small high speed direct injection (HSDI) turbocharged diesel engine by means of a parallel experimental and computational investigation. As far as the numerical approach is concerned, an in-house 1D research code for the simulation of the whole engine system has been enhanced by the introduction of a multizone quasi-dimensional combustion model, tailored for multijet direct injection diesel engines. This model takes into account the most relevant issues of the combustion process: spray development, air-fuel mixing, ignition, and formation of the main pollutant species (nitrogen oxide and particulate). The prediction of the spray basic patterns requires previous knowledge of the fuel injection rate. Since the direct measure of this quantity at each operating condition is not a very practical proceeding, an empirical model has been developed in order to provide reasonably accurate injection laws from a few experimental characteristic curves. The results of the simulation at full load are compared to experiments, showing a good agreement on brake performance and emissions. Furthermore, the combustion model tuned at full load has been applied to the analysis of some operating conditions at partial load, without any change to the calibration parameters. Still, the numerical simulation provided results that qualitatively agree with experiments.

1D Engine Simulation of a Small HSDI Diesel Engine Applying a Predictive Combustion Model

2006 ◽  
Author(s):  
T. Cerri ◽  
A. Onorati ◽  
E. Mattarelli
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Numerical Approach ◽  
Injection Rate ◽  
Operating Conditions ◽  
Combustion Model ◽  
Full Load ◽  
Partial Load

The paper analyses, by means of a parallel experimental and computational investigation, the performances of a small HSDI turbocharged Diesel engine. As far as the numerical approach is concerned, an in-house ID research code for the simulation of the whole engine system has been enhanced by the introduction of a multi-zone quasi-dimensional combustion model, tailored for multi-jet direct injection Diesel engines. This model takes into account the most relevant issues of the combustion process: the spray development, the in-cylinder air-fuel mixing process, the ignition and formation of the main pollutant species, such as nitrogen oxides and particulate. The prediction of the spray basic patterns requires the previous knowledge of the fuel injection rate. Since the direct measure of this quantity at each operating condition is not a very practical proceeding, an empirical model has been developed in order to provide reasonably accurate injection laws from a few experimental characteristic curves. The results of the simulation at full load are compared to experiments, showing a good agreement on brake performance and emissions. Furthermore, the combustion model tuned at full load has been applied without any change to the analysis of some operating conditions at partial load. Still, the numerical simulation provided results which qualitatively agree with experiments.

scholarly journals Investigation into the effect of different fuels on ignition delay of M-type diesel combustion process

2008 ◽  
Vol 12 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Dzevad Bibic ◽  
Ivan Filipovic ◽  
Ales Hribernik ◽  
Boran Pikula
Keyword(s):  
Diesel Engine ◽  
Ignition Delay ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Injection System ◽  
Biodiesel Fuel ◽  
Injection Timing ◽  
Injection Angle ◽  
Start Of Injection

An ignition delay is a very complex process which depends on a great number of parameters. In practice, definition of the ignition delay is based on the use of correlation expressions. However, the correlation expressions have very often limited application field. This paper presents a new correlation which has been developed during the research project on the direct injection M-type diesel engine using both the diesel and biodiesel fuel, as well as different values of a static injection timing. A dynamic start of injection, as well as the ignition delay, is defined in two ways. The first approach is based on measurement of a needle lift, while the second is based on measurement of a fuel pressure before the injector. The latter approach requires calculation of pressure signals delay through the fuel injection system and the variation of a static advance injection angle changing. The start of a combustion and the end of the ignition delay is defined on the basis of measurements of an in-cylinder pressure and its point of separation from a skip-fire pressure trace. The developed correlation gives better prediction of the ignition delay definition for the M-type direct injection diesel engine in the case of diesel and biodiesel fuel use when compared with the classic expression by the other authors available in the literature.

scholarly journals The Effect of RME-1-Butanol Blends on Combustion, Performance and Emission of a Direct Injection Diesel Engine

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2941
Author(s):  
Wojciech Tutak ◽  
Arkadiusz Jamrozik ◽  
Karol Grab-Rogaliński
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Direct Injection ◽  
Specific Energy Consumption ◽  
Combustion Process ◽  
Constant Load ◽  
Combustion Stability ◽  
Performance And Emission ◽  
Energy Share ◽  
The Stability

The main objective of this study was assessment of the performance, emissions and combustion characteristics of a diesel engine using RME–1-butanol blends. In assessing the combustion process, great importance was placed on evaluating the stability of this process. Not only were the typical COVIMEP indicators assessed, but also the non-burnability of the characteristic combustion stages: ignition delay, time of 50% heat release and the end of combustion. The evaluation of the combustion process based on the analysis of heat release. The tests carried out on a 1-cylinder diesel engine operating at a constant load. Research and evaluation of the combustion process of a mixture of RME and 1-butanol carried out for the entire range of shares of both fuels up to 90% of 1-butanol energetic fraction. The participation of butanol in combustion process with RME increased the in-cylinder peak pressure and the heat release rate. With the increase in the share of butanol there was noted a decrease in specific energy consumption and an increase in engine efficiency. The share of butanol improved the combustion stability. There was also an increase in NOx emissions and decrease in CO and soot emissions. The engine can be power by blend up to 80% energy share of butanol.

CFD Modelling of the Effects of Injection Timing on the Combustion Process and Emissions in an HSDI Diesel Engine

2012 ◽  
Author(s):  
Raouf Mobasheri ◽  
Zhijun Peng
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Cfd Simulation ◽  
Direct Injection ◽  
Combustion Process ◽  
Injection Timing ◽  
Cfd Modelling ◽  
Combustion Modeling ◽  
Pressure Trace ◽  
Hsdi Diesel Engine

High-Speed Direct Injection (HSDI) diesel engines are increasingly used in automotive applications due to superior fuel economy. An advanced CFD simulation has been carried out to analyze the effect of injection timing on combustion process and emission characteristics in a four valves 2.0L Ford diesel engine. The calculation was performed from intake valve closing (IVC) to exhaust valve opening (EVO) at constant speed of 1600 rpm. Since the work was concentrated on the spray injection, mixture formation and combustion process, only a 60° sector mesh was employed for the calculations. For combustion modeling, an improved version of the Coherent Flame Model (ECFM-3Z) has been applied accompanied with advanced models for emission modeling. The results of simulation were compared against experimental data. Good agreement of calculated and measured in-cylinder pressure trace and pollutant formation trends were observed for all investigated operating points. In addition, the results showed that the current CFD model can be applied as a beneficial tool for analyzing the parameters of the diesel combustion under HSDI operating condition.

Diesel engine performance mapping using a parametrized mixing time model

2017 ◽  
Vol 19 (2) ◽  
pp. 202-213 ◽  
Author(s):  
Michal Pasternak ◽  
Fabian Mauss ◽  
Christian Klauer ◽  
Andrea Matrisciano
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Mixing Time ◽  
Combustion Process ◽  
Engine Performance ◽  
Injection Timing ◽  
Engine Control ◽  
Reactor Model ◽  
Time Model ◽  
Tabulated Chemistry

A numerical platform is presented for diesel engine performance mapping. The platform employs a zero-dimensional stochastic reactor model for the simulation of engine in-cylinder processes. n-Heptane is used as diesel surrogate for the modeling of fuel oxidation and emission formation. The overall simulation process is carried out in an automated manner using a genetic algorithm. The probability density function formulation of the stochastic reactor model enables an insight into the locality of turbulence–chemistry interactions that characterize the combustion process in diesel engines. The interactions are accounted for by the modeling of representative mixing time. The mixing time is parametrized with known engine operating parameters such as load, speed and fuel injection strategy. The detailed chemistry consideration and mixing time parametrization enable the extrapolation of engine performance parameters beyond the operating points used for model training. The results show that the model responds correctly to the changes of engine control parameters such as fuel injection timing and exhaust gas recirculation rate. It is demonstrated that the method developed can be applied to the prediction of engine load–speed maps for exhaust NOx, indicated mean effective pressure and fuel consumption. The maps can be derived from the limited experimental data available for model calibration. Significant speedup of the simulations process can be achieved using tabulated chemistry. Overall, the method presented can be considered as a bridge between the experimental works and the development of mean value engine models for engine control applications.

Influence of Imperfections in the Working Media on Diesel Engine Indicator Process: Part 2 — Results

1998 ◽  
Author(s):  
Stanislav N. Danov ◽  
Ashwani K. Gupta
Keyword(s):  
Mathematical Model ◽  
Diesel Engine ◽  
High Pressures ◽  
Combustion Process ◽  
Ideal Gas ◽  
Working Medium ◽  
High Pressures And Temperatures ◽  
Specific Heat Capacities ◽  
Working Media ◽  
The Mathematical Model

Abstract In the companion Part 1 of this two-part series paper several improvements to the mathematical model of the energy conversion processes, taking place in a diesel engine cylinder, have been proposed. Analytical mathematical dependencies between thermal parameters (pressure, temperature, volume) and caloric parameters (internal energy, enthalpy, specific heat capacities) have been obtained. These equations have been used to provide an improved mathematical model of diesel engine indicator process. The model is based on the first law of thermodynamics, by taking into account imperfections in the working media which appear when working under high pressures and temperatures. The numerical solution of the simultaneous differential equations is obtained by Runge-Kutta type method. The results show that there are significant differences between the values calculated by equations for ideal gas and real gas under conditions of high pressures and temperatures. These equations are then used to solve the desired practical problem in two different two-stroke turbo-charged engines (8DKRN 74/160 and Sulzer-RLB66). The numerical experiments show that if the pressure is above 8 to 9 MPa, the working medium imperfections must be taken into consideration. The mathematical model presented here can also be used to model combustion process of other thermal engines, such as advanced gas turbine engines and rockets.

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