Working Process Of Engine Research Articles

Effects of lean combustion coupling with intake tumble on economy and emission performance of gasoline engine

To improve the economy and emission performance of automotive gasoline engine, the approach of lean combustion coupling with intake tumble was investigated. A port blocker was designed on intake manifold so as to generate intake tumble, and then the sweeping test of excess air coefficient was conducted under engine common conditions (2000 r/min, 2.6 bar) in two port blocker states (opening and closing). On this basis, the effects of lean combustion coupling with intake tumble on the working process, combustion and emission performance of gasoline engine were studied. The tested results indicate that lean combustion limit is obviously extended with acceptable combustion stability by utilizing intake tumble, thus the potential of energy conservation and emission reduction by lean combustion can be further enhanced. Compared with the initial state of original engine (λ = 1.0, port blocker closing), the indicated thermal efficiency can be increased by 7.2%, and the specific emissions of CO2, CO, HC and NOX can be reduced by 5.8%, 72.2%, 12.0% and 85.3% at most, respectively. In particular, the minimum specific emission of NOX is only 2.0 g/(kW·h). The results demonstrate that lean combustion coupling with intake tumble has great potential of energy conservation and emission reduction for gasoline engine.

Influence of the helicopter flight design speed on the selection of working process parameters for GTE

This paper considers issues of designing a gas-turbine engine in the helicopter system at the early design stages. The optimum and rational values of engine working process parameters at different flight speeds of the flight vehicle (FV) are analyzed. Several characteristics of mathematical models (MM) that form the helicopter–engine system, are described.

Influence of swirl ratio on fuel distribution and cyclic variation under flash boiling conditions in a spark ignition direct injection gasoline engine

One effective way of suppressing the cycle-to-cycle variation in engine is to design a combustion system that is robust to the root causes of engine variation over the entire engine working process. Flash boiling has been demonstrated as an ideal technique to produce stable fuel spray. But the generation of stable intake flow and fuel mixture remains challenging. In this study, to evaluate the capability of enhanced swirl flow to produce repeatable fuel mixture formation, the fuel distribution inside a single cylinder optical engine under two swirl ratios were measured using laser induced fluorescence technique. The swirl ratio was regulated by a swirl control valve installed in one of the intake ports. A 266nm wavelength laser sheet from a frequency-quadrupled laser was directed into the optical engine through the quartz liner 15mm below the tip of the spark plug. The fluorescence signal from the polycyclic aromatic hydrocarbon in gasoline was collected by applying a 320–420nm band pass filter mounted in front of an intensified charge coupled device camera. Test results show that the in-cylinder fuel distribution is strongly influenced by the swirl ratio. Specifically, under high swirl condition, the fuel is mainly concentrated on the left side of the combustion chamber. While under the low swirl flow, fuel is distributed more randomly over the observing plane. This agrees well with the measurements of the stable flame location. Additionally, the cycle-to-cycle variation of the fuel distribution were analyzed. Results show that well organized fuel mixture with lower cycle-to-cycle variation is achieved by enhanced swirl flow.

Quantitative study on in-cylinder combustion and heat release characteristic parameters of gasoline engine based on single variable sweeping tests

The single variable sweeping tests about the influence factors of in-cylinder combustion and heat release processes of gasoline engine were carried out based on a special test engine with open electronic control unit (ECU). Through secondary development on tested data, the characteristic parameters of three stages of premixed combustion processes were quantitatively studied and the common rules were summarized. On this basis, the semi-empirical models for combustion characteristic parameters were derived, and the quantitative relations between combustion characteristic parameters and engine operating parameters, including speed, load, spark advance angle and excess air coefficient, etc., have been built. Furthermore, the proposed semi-empirical models were applied to other engines, which were proved to be of satisfactory accuracy and reliability. The effects of excess air coefficient, RGF, load and intake tumble on combustion rate are mainly reflected in SA (spark advance)-10% combustion duration rather than 10–90% combustion duration, and the spark advance angle has little influence on SA-50% combustion duration. The summarized common rules and the proposed semi-empirical models can be used to predict the combustion characteristic parameters of engine, which is helpful for simulating and optimizing the in-cylinder working process of engine especially in design and development stage.

The Numerical Study of Compressed-Air Atomizer for Spark- ignited Jet Fuel Engine

There is increasing interest in the aircraft engine with spark ignition, which is capable of working using jet and diesel fuel. The reason is that the engines with spark ignition have a lower specific weight unlike diesel engines. The working process of the spark ignition engine which can operate on heavy fuels at the compression ratio of a base engine was described in our previous works. The operating cycle of this engine is implemented by the use of a compressed-air atomizer (CAA) in combination with a spray-guided concept. An ignition system has a traditional design and discharge parameters characteristic of gasoline engines. This paper presents a zero-dimensional mathematical model of the processes occurring in a CAA. The model verification is presented.

Dynamic cloud back-propagation networks and its application in fault diagnostic for liquid-propellant rocket engines

Fault diagnosis for liquid-propellant rocket engines often faces a lack of prior knowledge or insufficient sampling data, and thus becomes a decision-making problem with uncertain information sources. In this paper, a method based on dynamic cloud back-propagation networks is proposed. This uses cloud theory to synthetically combine randomness and fuzziness. In this work, a cloud model and back-propagation neural network are synthetically combined in series. A cloud transformation is used to identify the network structure and extract the features of the cloud model. Simultaneously, a unit-delay step is introduced into the input layer to describe the dynamic behaviour during the engine working process. The proposed fault diagnosis method for liquid-propellant rocket engines is verified using the actual data. The results confirm that the proposed method accurately recognizes all three relevant failure modes. Further, randomness associated with the measurement process and ambient noises are simulated by adding random noise to the test conditions. Simulation results demonstrate that the method correctly detects and classifies faults according to the principles of sustainability, indicating a high robustness towards noise. The proposed method has a single-step operating time of 1.24 × 10−4 s, satisfying the real-time requirements for fault diagnosis in liquid-propellant rocket engines.

Volume agglomeration process in quasi-dimensional direct injection diesel engine numerical model

This paper describes the quasi-dimensional numerical model for direct injection diesel engine, implemented in previously developed 0D model. The presented model uses a direct solution of equations for cylinder pressure and zone temperatures. A process of control volumes agglomeration from a set of the small fuel spray packages (control volumes) into one of the large ones is presented in details. This process contributes to fast simulation performances and to the numerical code stability. Numerical model validation was performed in three randomly selected engine operating points. Presented model results show a wide range of operating parameters which can be traced in detail, during the whole engine working process. Direct solution of temperature and pressure changes, in conjunction with the fuel spray packages agglomeration, presents a contribution to the quasi-dimensional engine process modeling.

The simulation methods based on 1D/3D collaborative computing for the vehicle integrated thermal management

The vehicle integrated thermal management containing the engine cooling circuit, the air conditioning circuit, the turbocharged inter-cooled circuit, the engine lubrication circuit etc. is the important means of enhancing power performance, promoting economy, saving energy and reducing emission. In this study, a 1D/3D collaborative simulation method is proposed with the engine cooling circuit and air conditioning circuit being the research object. The mathematical characterizations of the multiple thermodynamic systems are achieved by 1D calculation and the underhood structure is described by 3D simulation. Through analyzing the engine compartment integrated heat transfer process, the model of the integrated thermal management system is formed after coupling the cooling circuit and air conditioning circuit. This collaborative simulation method establishes structured correlation of engine-cooling and air conditioning thermal dissipation in the engine compartment, comprehensively analyzing the engine working process and air condition operational process in order to research the interaction effect of them. In the calculation examples, to achieve the integrated optimization of multiple thermal systems design and performance prediction, by describing the influence of system thermomechanical parameters and operating duty to underhood heat transfer process, performance evaluation of the engine cooling circuit and the air conditioning circuit are realized.

Comparative Overview of Marine Fuel Quality on Diesel Engine Operation

Publication devoted to the problem of translation of ship propulsion plant to low-sulfur fuel grades regulated by new International Maritime Organization (IMO) standards. Study and optimization of the physicochemical properties of marine fuels are important components in the work in order to improve energy efficiency and reduce toxic emissions from marine diesel engines. In the article gives the comparative analysis of standards of marine fuels. Using mathematical modeling, established variational indicated process characteristics of the diesel engine by simulating engine work in a wide range of fuels. As the object of the study was used diesel fuel, residual fuel, ethanol, RME and LNG. The aim of this work is to assess the impact of a number of properties of the fuel, in particular elemental chemical composition and calorific value to the energy performance of the working process of the diesel engine. Assessment carried out for the two cases of the diesel engine: the same cycle fuel delivery and implementations of the same indicated work, which is estimated at indicated pressure. The simulation results show that under the conditions of equal cyclic fuel supply differences indicated efficiency for different fuel are in the range 0.04–5%.

Computer-Aided System of Virtual Testing of Gas Turbine Engines

The article describes the concept of a virtual lab that includes subsystem of gas turbine engine simulation, subsystem of experiment planning, subsystem of measurement errors simulation, subsystem of simulator identification and others. The basis for virtual lab development is the computer-aided system of thermogasdynamic research and analysis “ASTRA”. The features of gas turbine engine transient modes simulator are described. The principal difference between the simulators of transient and stationary modes of gas turbine engines is that the energy balance of the compressor and turbine becomes not applicable. The computer-aided system of virtual gas turbine engine testing was created using the developed transient modes simulator. This system solves the tasks of operational (throttling, speed, climatic, altitude) characteristics calculation, analysis of transient dynamics and selection of optimal control laws. Besides, the system of virtual gas turbine engine testing is a clear demonstration of gas turbine engine working process and the regularities of engine elements collaboration. The interface of the system of virtual gas turbine engine testing is described in the article and some screenshots of the interface elements are provided. The developed system of virtual gas turbine engine testing provides means for reducing the laboriousness of gas turbine engines testing. Besides, the implementation of this system in the learning process allows the diversification of lab works and therefore improve the quality of training.

Research on aircraft engine actuator and sensor faults diagnosis with Takagi-Sugeno fuzzy model and H^∞ observer

This paper deals with aircraft engine actuator and sensor faults diagnosis with Takagi-Sugeno fuzzy model and H ∞ observer. At first, the T-S fuzzy system model of aircraft engine was built by dividing the envelope on the flight. The work process of aircraft engine can be divided into several regions and each region can be described using a set of state space model. Then these local current models can be integrated in full flight envelope to describe the engine working condition. With the nonlinear T-S model of aircraft engine, the actuator and sensor faults observers were designed with H ∞ bound norm to estimate the sensor and the actuator faults. In order to diagnose the faults of actuator and sensor simultaneously, a full faults diagnosis logical with T-S model and H ∞ observer was designed. With these steps, the aircraft engine actuator and sensor faults could be detected effectively. Finally, a numerical example is given to illustrate the design procedures. Simulation results show the satisfactory performances.

MATERIAL CONSUMPTION CRITERIA OF PISTON – CON – ROD ELEMENTS SYSTEM OF COMBUSTION ENGINE

The following article includes the analysis of mechanical and thermal load criteria of combustion engine. Those criteria have been divided into tribological, technical in detail and technical in general. The above criteria have been related to piston-con-rod system, in which, two tribological centres were specified. One centre included, piston-piston rings and cylinder, in which, piston rings serve as labyrinth seal and the cylinder constitutes piston guides. Crank bearings and main bearings of engine crankshaft constitute the second centre. From the point of tribological view, piston-piston rings and cylinder constitute slide and thrust bearing lubricated hydrodynamically, while crankshaft bearings a-c-t as slide and journal bearings also lubricated hydrodynamically. In the description of thermal load of the above-mentioned tribological centres, special attention was paid to criteria that ensure their motion reliability and durability of engine operation. Whereas in the description of mechanical load of elements constituting investigated centres, some criteria were determined resulting from their functionality and fatigue strength of the material they were made of. Criteria of thermal loads were based on mean density flux of heat conducted through the walls of engine elements, paying attention to their low precision of evaluation. It has been emphasized that synthetic criteria indicators are the most precise. They are determined on the basis of engine load measurements during its operation. Those criteria allow us to describe the operating process of con-rod-piston diesel engines and at the same time it is possible to expose their technical condition which is of essential practical meaning. The wear process of tribological centres that takes place during operating in piston-con-rod system, affects the course of engine working process and its techno-economic indicators.

Computer-aided system of virtual gas turbine engine testing

The article describes the concept of a virtual lab that includes subsystem of gas turbine engine simulation, subsystem of experiment planning, subsystem of measurement errors simulation, subsystem of simulator identification and others. The basis for virtual lab development is the computer-aided system of thermogasdynamic research and analysis ASTRA. The features of gas turbine engine transient modes simulator are described. The principal difference between the simulators of transient and stationary modes of gas turbine engines is that the energy balance of the compressor and turbine becomes not applicable. The computer-aided system of virtual gas turbine engine testing was created using the developed transient modes simulator. This system solves the tasks of operational (throttling, speed, climatic, altitude) characteristics calculation, analysis of transient dynamics and selection of optimal control laws. Besides, the system of virtual gas turbine engine testing is a clear demonstration of gas turbine engine working process and the regularities of engine elements collaboration. The interface of the system of virtual gas turbine engine testing is described in the article and some screenshots of the interface elements are provided. The developed system of virtual gas turbine engine testing provides means for reducing the laboriousness of gas turbine engines testing. Besides, the implementation of this system in the learning process allows the diversification of lab works and therefore improve the quality of training.

Assessing reduction gear mass in the problem of optimizing parameters of the working process of a turboprop engine at the initial design stage

The paper analyzes mathematical models of the mass of the reduction gear as part of a turboprop enginepower plant in the problem of optimizing the parameters of the working process of the gas turbine engine at theinitial design stage. The necessity of optimal matching of the main parameters of the power plant and the aircraftbased on their system performance criteria is the main feature of the initial design of turboprop engines. To solvethe problem of optimizing the parameters of the engine work process, under certain design constraints, it is importantto know the take-off weight of the aircraft in the formation of which the weight of the power plant with aturboprop engine is one of important components that actually determine the coordination of the aircraft andengine parameters. The mass of the reduction gear of a turboprop engine makes up a significant part of the powerplant mass. The existing models of the mass of the power plant with a turboprop engine do not separate theweight of the gear from the weight of the power plant. Thereby, the reduction gear weight is erroneously associatedwith gear parameters used in the model of the mass of the engine. This does not include theobvious dependence of the gear mass on the transmitted power which is closely linked to the distribution of the free energy of the turboprop engine.

THE RESEARCH OF SIMPLIFICATION OF 1.9 TDI DIESEL ENGINE HEAT RELEASE PARAMETERS DETERMINATION / 1,9 TDI DYZELINIO VARIKLIO ŠILUMOS IŠSISKYRIMO PARAMETRŲ NUSTATYMO SUPAPRASTINIMO TYRIMAS

The investigation of modified methodology of Audi 1.9 TDI 1Z diesel engine heat release parameters’ determination is represented in the article. In this research the AVL BOOST BURN and IMPULS software was used to treat data and to simulate engine work process. The reverse task of indicated pressure determination from heat release data was solved here. T. Bulaty and W. Glanzman methodology was modified for purpose to simplify the determination of heat release parameters. The maximal cylinder pressure, which requires additional expensive equipment, was changed into the objective indicator – exhaust gas temperature. This modification allowed to simplify the experimental engine tests and also gave simulation results in an error range up to 2% of main engine operating parameters. The study results are assessed as an important point for the simplification of engine test under field conditions. Straipsnyje pateikta dyzelinio Audi variklio 1,9 TDI 1Z šilumos išsiskyrimo parametrų nustatymo metodikos ir jos modifikavimo tyrimas. Šio tyrimo procese atilikto eksperimento duomenims apdoroti ir darbo procesui modeliuoti panaudoti AVL BOOST BURN ir IMPULS programiniai paketai. Tyrime buvo sprendžiamas atvirkščias indikatorinio slėgio nustatymo iš šilumos charakteristikos duomenų uždavinys. Siekiant supaprastinti šilumos išsiskyrimo parametrų nustatymą, panaudota modifikuota T. Bulaty ir W. Glanzman metodika. Maksimalaus slėgio cilindre parametras, kurio nustatymas reikalauja papildomos brangios įrangos, buvo pakeistas objektyviu išmetamųjų dujų temperatūros parametru. Šis modifikavimas leidžia supaprastinti eksperimentinius tyrimus bei leido atlikti pagrindinių variklio darbo parametrų modeliavimą neviršijant 2 % paklaidų ribos. Tyrimo rezultatas vertinamas itin svarbiu variklių bandymų lauko sąlygomis supaprastinimo atžvilgiu.

THE INFLUENCE OF HYDROGEN GAS ON THE MEASURES OF EFFICIENCY OF DIESEL INTERNAL COMBUSTION ENGINE / VANDENILIO DUJŲ ĮTAKA DYZELINIO VIDAUS DEGIMO VARIKLIO EFEKTYVUMO RODIKLIAMS

In this research paper energy and ecological parameters of diesel engine which works under addition of hydrogen (10, 20, 30 l/ min) are presented. A survey of research literature has shown that addition of hydrogen gases improve diesel combustion; increase indicated pressure; decrease concentration of carbon dioxide (CO2), hydrocarbons (HC), particles; decrease fuel consumptions. Results of the experiment revealed that hydrogen gas additive decreased pressure in cylinder in kinetic combustion phase. Concentration of CO2 and nitrous oxides (NOx) decreased not significantly, HC – increased. Concentration of particles in engine exhaust gases significantly decreased. In case when hydrogen gas as additive was supplied, the fuel consumptions decreased a little. Using AVL BOOST software combustion process analysis was made. It was determined that in order to optimize engine work process under hydrogen additive usage, it is necessary to adjust diesel injection angle. Straipsnyje pateikiamas dyzelinio variklio, veikiančio su vandenilio priedu (10, 20, 30 l/min), energetinių ir ekologinių rodiklių tyrimas. Atlikus literatūros apžvalgą pastebėta, kad vandenilio dujų priedas pagerina dyzelino degimą, padidina indikatorinį slėgį, sumažina anglies dvideginio (CO2), angliavandenilių (HC), kietųjų dalelių koncentraciją, sumažina degalų sąnaudas. Bandymo rezultatai parodė, kad vandenilio dujų priedas sumažino variklio indikatorinį slėgį kinetinės degimo fazės metu. CO2 ir azoto oksidų (NOx) koncentracija nedaug sumažėjo, HC – padidėjo. Kietųjų dalelių koncentracija variklio išmetamosiose dujose itin sumažėjo. Tiekiant vandenilio dujas kaip priedą nedaug sumažėja dyzelino sąnaudos. AVL BOOST programa atlikta degimo proceso analizė. Nustatyta, kad siekiant optimizuoti variklio darbą, naudojant vandenilio priedą, būtina reguliuoti dyzelino įpurškimo paskubos kampą.

A Quasi-Dimensional Model of Diesel Engine Working Process in Hardware-in-the-Loop Simulation System

In order to simplify the model of diesel engine working process in Hardware-In-the-Loop simulation system and improve its real time operating performance, a quasi-dimensional model of diesel engine working process based on a new phase divided spray mixing model was formulated and developed. The software MATLAB/Simulink was utilized to simulate the diesel engine working process. The good agreement between experimental results and calculated results indicates that the quasi-dimensional model of diesel engine working process is reliable for predicting power, fuel consumption and emissions of diesel engine. It is concluded that the quasi-dimensional model of diesel engine working process was greatly simplified and the real time operating performance of simulation system was obviously improved by using this phase divided spray mixing model.

Switching control of thrust regulation and inlet unstart protection for scramjet engine based on Min strategy

Scramjet engine encounters many safety restrictions during the ascent trajectory. These restrictions make the engine a multi-objective control system. In order to obtain optimal thrust performance while avoiding the inlet unstart, switching control based on Min strategy has been focused on in the working process of scramjet engine. Firstly, on the basis of experimental data, the dynamic mathematical models of fuel supply system, thrust regulation control loop and inlet unstart protection loop were established. Min strategy and PI controller were applied to the scramjet engine and the influence of integral limiter of PI controllers on the control process was discussed using the hardware-in-the-loop simulation. Finally, the validity of switching control was verified on the ground experiment facility. The results showed that it is useful to introduce the multi-objective switching control to scramjet engine. Switching control based on Min strategy could effectively maximize the engine performance while avoiding the inlet unstart.

NUMERICAL INVESTIGATION ON THE EFFECTS OF GASOLINE AND HYDROGEN BLENDS ON SI ENGINE COMBUSTION

Even small amount additive (10…15% by volume from whole air amount) of hydrogen (H2) into spark ignition (SI) engines obviously effects ecological parameters and engine efficiency because of H2 exclusive properties. SI engine work process simulation was made using AVL Boost simulation software. Analysis of results showed that engine power depends a lot on H2 supply technique into engine; NOx amount in exhaust gases directly proportional to the amount of H2, however, making mixture leaner up to λ = 1.6, it is possible to reach significant NOx decrease. Increased amount of H2 as an additive in fuel, changes H/C ratio in fuel mixture, also hydrogen improves properties of the mixture (particularly lean) and combustion of hydrocarbons what can be a reason of decreased HC emissions in exhaust gases. Keyword(s): Hydrogen and gasoline mixture, engine efficiency, exhaust gases, nitrous oxides, hydrocarbons, simulation.

Design of Variable Valve Agency for Gasoline Engine Based on AVLBOOST

As an important technological means for engines’ low emission with high efficiency, variable valve agency is widely applied in the new-type machine’s R&D and the old-type machine’s modification. This paper applies AVL BOOST one-dimensional simulation software to the working process of the small displacement electronic control gasoline engine and proceeds with the analog simulating calculation. The data error between the calculated result and the original experiment one is less than 5%, so the calculation precision meets the requirements. As formulating simulation study programs and analyzing the valve timing parameters’ impact on the low-emission electronic control gasoline engine’s performances, this paper finds the intake duration angle, the exhaust advance angle, and the valve overlap, all receive big impacts; the original machine’s valve timing optimizes the treatment of working conditions with high speed while sacrificing the power performance of low-speed working conditions. On this basis, this paper designs the variable valve mechanism, and improves the original machine’s medium-and-low rotating speed’s torque by 10% or so.