Model Of Internal Combustion Engine Research Articles

Finite-time energy conversion in a hybrid cycle combining electrochemical, combustion and thermochemical recuperation processes

Conversion of fuel chemical energy into electrical and mechanical work in a hybrid cycle combining electrochemical, combustion and thermochemical recuperation (TCR) processes is numerically analyzed. Finite-time thermodynamics is employed to account for the different efficiency dependency on energy conversion rate of each process involved in the cycle. Fuel cell (FC) zero-dimensional (0D) model is employed to simulate the electrochemical reaction in a solid-oxide FC (SOFC), and a finite-speed finite-time thermodynamics (FST-FTT) model of spark-ignition internal combustion engine (SI-ICE) is created for the combustion process simulation. The prediction results show that without TCR, in the range of cycle efficiencies between 50% and 60% there is a potential of power gain by the hybrid cycle compared to the FC. The achievable efficiency levels are much higher if waste heat recovery through TCR is employed. In such a case, the cycle efficiency can reach values above 70% with a significant power gain compared to FC operating along. However, in almost any conditions, a maximal specific power is inferior compared to the ICE.

Internal Combustion Engine Modeling Framework in Simulink: Combustion Modeling

An internal combustion engine modeling framework has been developed in the MATLAB/Simulink environment to allow engine component blocks to be connected in a physically representative manner to reduce the model build time. Each component block, derived from physical laws, interacts with other blocks according to block connection. In this series paper, detailed combustion modeling is presented among several engine subsystems. In the engine modeling framework, combustion is represented by a spherical flame propagating from the spark plug, and the burn rate is correlated to combustion chamber geometry, laminar flame speed, and turbulence. To accurately predict the burn rate, the quasi-dimensional model requires tuning. The combustion model has been computationally validated in a previous study and will be experimentally validated with real engine test data in the next series paper.

Mean-Value Exergy Modeling of Internal Combustion Engines: Characterization of Feasible Operating Regions

Abstract In this paper, a novel mean-value exergy-based modeling framework for internal combustion engines is developed. The characterization of combustion irreversibilities, nonstoichiometric combustion, and thermal exchange between the in-cylinder mixture and the cylinder wall allows for a comprehensive description of the availability transfer and destruction phenomena in the engine. The model is applicable to internal combustion engines operating both at steady-state and over a sequence of operating points and is used to create maps describing the exergetic static behavior of the engine as a function of speed and load. The application of the proposed modeling strategy is shown for a turbocharged diesel engine. Ultimately, the static maps, while providing insightful information about inefficiencies over the operating range of the engine, are the enabling step for the development of exergy-based control strategies aiming at minimizing the overall operational losses of hybrid electric vehicles.

Generation of Rate-of-Injection (ROI) profile for Computational Fluid Dynamics (CFD) model of Internal Combustion Engine (ICE) using machine learning

Injector configuration and spray characteristics are important parameters that define diesel combustion and emissions performance. One of the critical spray inputs is the Rate-of-Injection (ROI) profile. The ROI profile depends on the spray's operating conditions, including nozzle geometry (e.g., nozzle diameter), injection pressure, and injection duration. Besides, the internal nozzle flow phenomenon and external ambient conditions can further impact fuel introduction characteristics. This study measured the ROI profile of a heavy-duty (multi-hole) diesel injector using the Bosch tube technique. Injection pressure and injection duration were varied from 600 to 2600 bar and 0.5–3.0 ms, respectively. After post-processing, measurement data were then used to train numerical models, including a developed machine learning (ML) model that can create very similar ROI profiles with experimental data. Next, a Computational Fluid Dynamics (CFD) simulation used the ROI profile generated by ML model. For comparison, there are other simplified ROI profiles used in similar CFD simulation configuration. Results showed that the any difference in ROI profiles could affect the combustion and emissions significantly. This further emphasizes the need to provide high-fidelity spray input in terms of ROI profile for CFD simulation. The current ML model can deliver a realistic ROI profile for any given rail pressure and injection duration.

Effects of Backpressure on the Performance of Internal Combustion Engine and Automobile Exhaust Thermoelectric Generator

Abstract The maximum generated power of automobile exhaust thermoelectric generator (AETEG) can be enhanced by applying inserted fins to its heat exchanger, because the temperature difference of thermoelectric modules (TEMs) is increased. However, the added heat exchanger will result in undesired backpressure, which may deteriorate the performance of the internal combustion engine (ICE). To evaluate the backpressure on the performance of both the ICE and the AETEG, the model of ICE integrated with AETEG was established with the GT-power software and validated with the AETEG test bench. The heat exchangers with chaos shape and fishbone shape were proposed, their pressure drop with different engine speeds was studied, and their effects on the performance of both the AETEG and the ICE were analyzed. The results show that compared with the fishbone-shaped structure, the pressure drop of chaos-shaped heat exchanger is larger at the same engine speed, which contributes to the increased maximum power and hot side temperature of the AETEG. Moreover, compared with the ICE without heat exchanger, the brake torque, brake power, volumetric efficiency, pumping mean effective pressure, CO emission, and CO2 emission of the ICE assembled with chaos-shaped and fishbone-shaped heat exchanger reduce, and the corresponding brake-specific fuel consumption increase because of the raised backpressure caused by the heat exchanger.

Model predictive control of a dual fuel engine integrated with waste heat recovery used for electric power in buildings

AbstractWaste heat recovery (WHR) system uses the thermal energy from the exhaust gases of an internal combustion engine (ICE) to assist in the electricity generated by the ICE generator in buildings. This paper presents a model predictive control (MPC) framework to minimize the fuel consumption of an ICE by integrating it with a WHR system. To this end, a control oriented model of a WHR system is developed and then integrated to a control oriented model of a turbocharged dual fuel diesel‐natural gas ICE. The ICE model is derived based on experimental data collected from a 6.7 L Cummins ISB engine modified for dual fuel operation. The designed MPC framework optimizes the ICE combustion, turbocharger, and organic Rankine cycle (ORC) system in the WHR to minimize fuel consumption of the ICE. The designed control framework also allows to meet time‐varying exhaust gas temperature requirements of the ICE to meet exhaust emission constraints. The results show that the optimal operation of the WHR and the ICE reduces the fuel consumption of the ICE by 6.7%.

Точность идентификации состояния двигателей внутреннего сгорания с настраиваемой моделью с помощью измерительной экспертной системы

Рассмотрены вопросы уменьшения погрешности идентификации технического состояния двигателя внутреннего сгорания и его составных частей как объекта экспертизы путем настраивания параметров применяемой в измерительной экспертной системе виртуальной модели ДВС. Для настройки модели предложено применение градиентного метода, обеспечивающего наиболее быструю минимизацию погрешности идентификации Purpose and methods. Improving the accuracy of identification for the technical condition of the internal combustion engine (ICE) in operational conditions using the engine measurement expert system (EMSE) is addressed by adjusting the computer dynamic model of the internal combustion engine. Results. Algorithmic schemes of computer models for the state of the ICE are obtained using the equations of its dynamics, which takes into account the factors such as the movement of the fuel supply body, the force on the hook - the load. The structural schemes of modeling at the input of a step-by-step action are presented. A promising method of tuning the model in the EMSE is proposed, which consists of measuring its working processes, in particular the angular acceleration of the crankshaft, for a specific brand of ICE. Then the corresponding set of models of its technical condition is obtained: normal, permissible, limit, pre-accident and emergency. By adjusting the values of the coefficients of these models in the EMSE, they achieve their coincidence with the actual state of the ICE. The identification error is minimized using the gradient method of steepest descent. The presence of several computer models is a practical advantage in the examination of the technical condition of the tested engines allowing its effective implementation in operational conditions. In this case, based on the experience of operation, the computer model closest to the actual state of the ICE is adjusted. At the same time, the efficiency of localization of ICE malfunctions increases, since the coefficients reflecting the state of the engine components and systems are consistently adjusted. Conclusions. The application of the proposed methodology using the criterion of minimizing the identification error by the gradient method allows implementation of this effective method for identifying the state of the ICE. It increases the reliability of determining the technical state of the ICE and its components by adjusting the computer model

Measurement and modelling of a linear electromagnetic actuator driven camless valve train for spark ignition IC engines under full load condition

Camless engine valve train for gasoline engines particularly port injection engines offer major improvements over traditional system with fixed valve timing and lift, in terms of efficiency, maximum torque and power, and emissions. Electromagnetic driven valve actuators are very promising in this context, but there are significant control problems. The use of displacement sensor could add extra cost to the camless engine. In this work, a moving coil actuator driven valve train was designed and prototyped and a 1D single-cylinder internal combustion engine model was built to investigate the benefit of without throttle by adopting such camless valve train using Ricardo WAVE under full load operating conditions. A novel low-cost sensor named linear actuator position sensor (LAPS) based on flux linkage change on search coil was constructed in LabVIEW by using current, voltage and proximity sensors to detect the valve lift. The measurement of valve lift and current was reported to prove the feasibility of the camless valve train. The valve lift was used for the single-cylinder engine model and the simulation shows that the peak overall engine efficiency using camless valve train reaches 38.2% and the peak torque increases by 5 Nm compared conventional throttled engine under full load operating conditions. The LAPS model was validated by the experimental valve lift and the high accuracy indicates that the LAPS can be adopted for future development of camless valve train for spark ignition IC engines.

Use of biogas containing CH4, H2 and C02 in controlled auto-ignition engines to reduce NOx emissions

The use of biogas in internal combustion engines presents many advantages. Nevertheless, the CO2 content in the fuel negatively affects the combustion process, reducing combustion speed and stability. The presence of hydrogen in the biogas would improve its combustion characteristics. This paper investigates the combustion of biogas in a Controlled Auto Ignition (CAI) engine by means of numerical simulations. A model of the combustion system was developed for analyzing the use of biogas in a Chemkin environment. The biogas considered in this paper naturally contains hydrogen as a result of a new anaerobic digestion process. The CAI internal combustion engine model allowed the evaluation of engine performance and emissions. Different hydrogen contents were investigated to find the optimal fuel composition for reducing nitrogen oxides emission. Exhaust Gas Recirculation (EGR) was adopted for controlling in-cylinder temperature and therefore fuel auto-ignition. In fact, the presence of very reactive chemical species in the EGR, such as nitric oxide (NO), resulted to have an important impact on the onset of combustion. The results demonstrated that biogas containing hydrogen allow a reduction of NOx emissions with respect to a conventional biogas. An optimal biogas composition was identified, allowing a 32% reduction in NOx emission compared to the conventional biogas. The reaction mechanism for NO formation did not change with biogas composition, with an important contribution coming from prompt NOx formation mechanism. The main differences were in the reaction rates, higher for the conventional biogas.

Small Cogeneration Unit with Heat and Electricity Storage

A micro cogeneration unit based on a three-cylinder internal combustion engine, Skoda MPI 1.0 L compressed natural gas (CNG), with an output of 25 kW at 3000 RPM is proposed in this paper. It is a relatively simple engine, which is already adopted by the manufacturer to operate on CNG. The engine life and design correspond to the original purpose of use in the vehicle. A detailed dynamic model was created in the GT-SUITE environment and implemented into an energy balance model that includes its internal combustion engine, heat exchangers, generator, battery storage, and water storage tank. The 1D internal combustion engine model provides us with information on engine start-up time, actual effective power, friction power, and the amount of heat going to the cooling system and exhaust pipe. The catalytic converter was removed from the exhaust pipe, and the engine was always operating at full load; thus, engine power control is not considered. An energy storage system for an island operation of the entire power unit for a large, detached house was designed to withstand accumulated energy for a few days in the case of a breakout. To reach a low initial system cost, the possible implementation of worn-out battery packs toward emission reduction in terms of the second life of the battery is proposed. The energy and emission balance are carried out, and the service life of the engine is also discussed.

Performance analysis of HCCI and PCCI engines using computational fluid dynamics

In the current study, a numerical simulation for a three dimensional model of internal combustion (IC) engine consists of inlet valve, exhaust valve, inlet manifold and exhaust manifold, was carried out to analyse the HCCI and PCCI strategies using ANSYS 16.2. The computational fluid dynamics (CFD) analysis was carried out for different swirl numbers and essentially moderate values of the engine speed. The converged results of both the combustion strategies were compared for different wall adjacent temperature, mass average static pressure, apparent heat release rate and mass average turbulent kinetic energy. The outcome of simulations reflected that a PCCI combustion strategy is better than HCCI combustion strategy at lower rpm, while at the moderate and higher values of engine rpm, HCCI combustion strategy demonstrated better performance in terms of temperature, pressure and turbulent kinetic energy. Interestingly, the exergy destruction rate was observed higher in the case of homogeneous charge compression ignition combustion strategy.

사회연결망 분석을 이용한 내연기관차와 전기자동차 부품 공급 네트워크 비교 분석

사회연결망 분석을 이용한 내연기관차와 전기자동차 부품 공급 네트워크 비교 분석

Methodological basis for measuring expert systems automation of motor and tractor Engines

The paper considers issues of increasing the efficiency of application of measuring expert systems (MES) that solve the problem of reducing power losses of motor and tractor internal combustion engines (ICE) in production conditions due to changes in their technical condition. MES carry out operational control of the energy parameters of the machine and tractor fleet for taking timely repair and maintenance actions. A methodological approach is proposed for creating an automation system for the development of MES, which increases the efficiency of the formation of MES due to the existing expertise in this subject area. The methodological basis of research is a dynamic method for diagnosing ICE. This method uses a test dynamic effect on ICE, which is the most practical for assessing the state of tractor ICE in production conditions, as well as computer modeling of the ICE work processes in order to find informative diagnostic indicators characterizing energy parameters. On the basis of the proposed target function, the software was determined in the form of the model describing a variety of system elements, their features and states, as well as links between them. Information provision was organized, carrying out the functions of collecting, processing and providing information upon request. A method for constructing a logical scheme of the development algorithm MES was formed, which formalizes the process of solving interrelated problems in the synthesis of various structures of hardware and software based on a set of mathematical models. On the example of modeling an ICE unit – a working machine, the effect of varying the input parameters of the model was estimated: torque effects and resistance moments on the diagnostic parameters of the technical state – angular velocities and accelerations. The use of computer modeling of ICE working processes using this methodological approach made it possible to create a digital technology and a measuring system for automated energy monitoring of the tractor fleet of an agricultural enterprise. The computer structural diagrams of ICE and MES models can be used in diagnostic complexes. This will make it possible to increase the accuracy and reliability of determining the state of the internal combustion engine and the mechanisms and working machines aggregated with it, as well as improve the quality of the work they perform.

A Methodology for Measuring Turbocharger Adiabatic Maps in a Gas-Stand and Its Usage for Calibrating Control Oriented and One-Dimensional Models at Early ICE Design Stages

Abstract In this work, a methodology is proposed to standardize turbochargers testing based on measuring the maps twice: in close to adiabatic and in diathermal conditions. Along the paper, it is discussed with special detail the impact of the procedure followed to achieve said quasi-adiabatic conditions in both the energy balance of the turbocharger and the testing complexity. As a conclusion, the paper proposes a methodology which combines quasi-adiabatic tests (cold and hot gas flow) with diathermal tests (hot gas flow) in order to extract from a turbocharger gas-stand all information needed by engine designers interested in controlling or one-dimensional-modeling the internal combustion engine (ICE). The methodology is completed with a guide for calibrating said control-oriented turbocharger models in order to separate aerodynamic efficiency (adiabatic) from heat transfer (HT) losses and from friction losses in the analysis of the turbocharger performance. The outsourced calibration of the turbocharger model allows avoiding uncertainties in the global ICE model calibration, what is very interesting for turbochargers benchmarking at early ICE-turbo matching stages or for global system analysis at early control design stages.

Internal Combustion Engine Modeling Framework in Simulink: Gas Dynamics Modeling

With advancements in computer-aided design, simulation of internal combustion engines has become a vital tool for product development and design innovation. Among the simulation software packages currently available, MATLAB/Simulink is widely used for automotive system simulations, but does not contain a comprehensive engine modeling toolbox. To leverage MATLAB/Simulink’s capabilities, a Simulink-based 1D flow engine modeling framework has been developed. The framework allows engine component blocks to be connected in a physically representative manner in the Simulink environment, reducing model build time. Each component block, derived from physical laws, interacts with other blocks according to block connection. In this Part 1 of series papers, a comprehensive gas dynamics model is presented and integrated in the engine modeling framework based on MATLAB/Simulink. Then, the gas dynamics model is validated with commercial engine simulation software by conducting a simple 1D flow simulation.

Numerical continuation applied to internal combustion engine models

This paper proposes tools from bifurcation theory, specifically numerical continuation, as a complementary method for efficiently mapping the state-parameter space of an internal combustion engine model. Numerical continuation allows a steady-state engine response to be traced directly through the state-parameter space, under the simultaneous variation of one or more model parameters. By applying this approach to two nonlinear engine models (a physics-based model and a data-driven model), this work determines how input parameters ‘throttle position’ and ‘desired load torque’ affect the engine’s dynamics. Performing a bifurcation analysis allows the model’s parameter space to be divided into regions of different qualitative types of the dynamic behaviour, with the identified bifurcations shown to correspond to key physical properties of the system in the physics-based model: minimum throttle angles required for steady-state operation of the engine are indicated by fold bifurcations; regions containing self-sustaining oscillations are bounded by supercritical Hopf bifurcations. The bifurcation analysis of a data-driven engine model shows how numerical continuation could be used to evaluate the efficacy of data-driven models.

Development of a mathematical model of an autonomous power supply source with a free piston motor on the basis of a synchronous electric returning machine with a permanent magnets

One of the current trends at present is the development of small energy, which is a particularly urgent task for the Russian Federation with its vast territories and the specifics of the electric power system. In the Russian Federation, the bulk of the electricity is generated at large power plants and transmitted through power lines. 60–70% of the country's territory lacks a centralized power supply, where more than 20 million people live, and the development of small and micro-energy facilities is necessary. Using a synchronous electric reciprocating machine with permanent magnets in power plants of a modular type makes it possible to rationally design an autonomous power supply source, to obtain the most optimal design. The development of methodological design decisions and the optimization of engine design parameters as part of generating and drive complexes is an important scientific task. A mathematical description of thermodynamic processes in a free-piston internal combustion engine, electromechanical and thermal processes occurring in a synchronous electric reciprocating machine with permanent magnets is developed, which is a necessary condition for designing and optimizing the design of an autonomous electric power complex. According to theoretical calculations, in the Matlab application, on the basis of the additional Simulink module, a simulation model of a free-piston internal combustion engine, linear current load calculation units, stator magnetic induction, magnetic induction created by permanent inductor magnets, electromagnetic force were developed and calculated. The created procedure for calculating the parameters of the electromagnetic component of the force of a synchronous machine with permanent magnets allows you to calculate and optimize the design parameters of the inductor and stator element of the electric motor under consideration. Thus, this will allow us to design electric machines with improved energy characteristics, due to the use of the obtained simulation results, which will allow us to use them more efficiently in the composition of generating and drive complexes.

Turbulent Reactive Flow Modeling in Engines: Simulating Engine Dynamics Using fearce

Abstract The Los Alamos turbulent reactive flow researchers, our modelers, and simulation code developers have succeeded in providing the engine research and development community an encompassing, robust, accurate, and easy-to-use software for engine modeling or simulations. This software is now known as the fearce Toolkit. In this paper, we discuss the physics present in the engine by discussing the methods we have employed to solve the model equations within the toolkit. Provided is background on what has been developed recently at LANL for internal combustion engine modeling.

Development and application of empirical models to optimize the control of an internal combustion engine

Introduction. The quality of the engine control units software (SW) significantly determines the output performance of the internal combustion engine (ICE). An important component of the software development process is its adaptation or calibration, which includes a large amount of work to select specific values of control actions to improve the performance of the internal combustion engine operating cycle under toxicity restrictions. The purpose of the work was to reduce time and material costs during the initial calibration work. Methodology and research methods . To achieve the goal the application of the calibration technique to the gasoline engine control system was proposed which was to be carried out by using empirical (obtained experimentally) ICE models. The main tool used in the work was the ASCMO software, which was used with ETAS technical support. The calibration process presented in the article was divided into stages: development of an experiment plan, testing (carried out on a gasoline engine model), analysis and processing of the results with the construction of an empirical ICE model, optimization of controlled influences and preparation of calibration maps taking into account the restrictions of harmful emissions during car cycle testing. Scientific novelty and results . The technique of initial ICE calibration based on the use of an empirical engine model has been formulated. The presented results were obtained without taking into account the statutory norms and rules, the imposed restrictions were formed in an arbitrary way. Practical significance . The presented method is of practical importance, since it allows to optimize labor costs for carrying out calibration work. A brief assessment of the effectiveness and applications of the technique is provided in the publication.

Engine Valvetrain Lift Prediction Using a Physic-based Model for The Electronic Control Unit Calibration

The electronic control has an increasingly important role in the evolution of the internal combustion engine (ICE) and the vehicle. Research in the automotive sector, in this historical period, is dictated by three main guidelines: reducing polluting emissions and fuel consumption while maintaining high performance. The Electronic Control Unit (ECU) has made it possible, complicating the engine both in terms of architecture and in terms of strategies, controlling, through simplified functions, physical phenomena in an ever more precise way. The ECU functions are experimentally calibrated, reducing the error between the quantity estimated by the function and the experimental quantity over the entire operating range of the engine, developing extensive experimental campaigns. The calibration process of the ECU functions is one of the longest and most expensive processes in the development of a new vehicle. Some lines of research have been explored to reduce the experimental tests to be carried out on the test bench. The use of neural networks (NN) has proven to be effective, leading to a reduction in experimental tests from 40 to 60%. Another methodology consists in the use of 1D/0D Thermo-fluid dynamic models of the ICE. These models are used as virtual test benches and through them it is possible to carry out the experimental campaigns necessary for the calibration of the control unit functions. At the real test bench, only the few experimental tests necessary for the validation of the model must be carried out. One of the simplifications that is usually made in the 1D/0D ICE models consists in assigning a single intake and exhaust valve lift, without taking into account the effect of the engine speed on the valve lift in early intake valve closure (EIVC) mode for engines equipped with VVA. This phenomenon has a not negligible effect on engine performance, especially at high engine speeds. In the case of engine models equipped with VVA, the valve lift cannot be imposed, since it is unique for each closing angle at each engine speed. Indeed, in order to assign the correct valve lift for a given engine speed and EIVC, numerous experimental tests should be carried out, making vain the beneficial effects of the method. In this work, the authors propose the use of a 0D/1D CFD model of the entire electro-hydraulic valvetrain VVA module, coupled with 1D lumped mass for reproducing the linear displacements of the intake valve, and for simulating the interactions between flow and mechanical systems of the solenoid hydro-mechanical valve. Thus, model simulations allow to predict the valve lift in all the necessary conditions in the experimental campaigns for the calibration of the control unit functions. Starting from geometric valvetrain data, the model has been validated with a parametric analysis of some variables on which there was greater uncertainty, by comparing the valve lift obtained by the model with the experimental ones in certain engine speeds. Subsequently, the authors have obtained the valve lifts in conditions not used for model validation, comparing them with their respective experimental lifts. The model has proven to be sensitive to the effect of the variation of the engine speed, reproducing the valve lift with a low error. In this way it is possible to reduce the experimental effort aimed to the calibration process considering that the virtual experimental campaign has proven to be reliable.