Застосування 1,3-дифенілтріазена як антидетонаційної присадки до автомобільних бензинів.

The expediency of using vehicles of liquefied petroleum gas as a motor fuel, as com-pared with traditional liquid motor fuels, in particular with diesel fuel, is shown. The advantages of converting diesel engines into gas ICEs with forced ignition with respect to conversion into gas diesel engines are substantiated. The analysis of methods for reducing the compression ratio in diesel engines when converting them into gas ICEs with forced ignition has been carried out. It is shown that for converting diesel engines into gas ICEs with forced ignition, it is advisable to use the Otto thermo-dynamic cycle with a decrease in the geometric degree of compression. The choice is grounded and an open combustion chamber in the form of an inverted axisymmetric “truncated cone” is developed. The proposed shape of the combustion chamber of a gas internal combustion engine for operation in the LPG reduces the geometric compression ratio of D-120 and D-144 diesel engines with an unseparated spherical combustion chamber, which reduces the geometric compression ratio from ε = 16,5 to ε = 9,4. The developed form of the combustion chamber allows the new diesel pistons or diesel pistons which are in operation to be in operation to be refined, instead of making special new gas pistons and to reduce the geometric compression ratio of diesel engines only by increasing the combustion chamber volume in the piston. This method of reducing the geometric degree of compression using conventional lathes is the most technologically advanced and cheap, as well as the least time consuming. Keywords: self-propelled chassis SSh-2540, wheeled tractors, diesel engines D-120 and D-144, gas engine with forced ignition, liquefied petroleum gas (LPG), compression ratio of the internal com-bustion engine, vehicles operating in the LPG.

Performance tuning improvement of modern diesel engines exerts an influence on technical and economic, ecological and resource indices of an internal combustion engine (ICE). In its turn, that requires a complex estimation and improvement of engine indices. As is known, working process and thermal intensity of combustion chamber parts are interconnected between themselves. Changes in design, operating and adjustment parameters of systems and structural elements of internal combustion engines that enable air-fuel mixing and combustions processes stressed state of combustion chamber parts. Joint estimation of operating cycle parameters and strength indices of ICE parts makes it possible to solve a number of problems originating in the process of designing new engine models and further development of the existing ones. The paper provides results of comparative estimation on heat-stressed state of a cylinder head for a high-speed diesel engine Д21A (2Ч10,5/12) while operating a rated power mode. In order to simulate and specify a heat-stressed state for description of boundary heat conductivity conditions the following adjoint “gas – wall” problems have been solved: the first one – for combustion chamber of a diesel engine (an internal problem) – simulation of a working cycle for a diesel engine; the second one – for cooling edges while blowing over them by air flow (an external problem). Calculations have been made in three-dimensional non-stationary presentation within the Cartesian coordinates. In order to simulate a working cycle of the diesel engine a computational grid describing combustion chamber configuration, inlet and outlet channels has been used in the paper. Solution of the external problem for cooling edge surface in case of blowing over them by air flow has permitted to specify temperatures and heat-transfer coefficient and later to improve an accuracy while estimating level of temperatures and stresses of the cylinder head.

The paper formulates the issue of development of experimental base with noninvasive optical-electronic tools for control of combustion in a combustion chamber of gas turbine engine. The design and specifications of a pilot sample of optronic system are explained; this noninvasive system was created in the framework of project of development of main critical technologies for designing of aviation gas turbine engine PD-14. The testbench run data are presented.

An experimental study on quenching crevice widths in the combustion chamber of a spark-ignition engine

In the present work, a convergent–divergent nozzle with a multi‐inlet combustion chamber of a rocket engine is numerically investigated to precisely understand the flow dynamics and variation of flow properties like pressure, temperature, and velocity distribution. The work also deals with a modified combustion chamber having multiple inlets. According to the entry conditions, when the propellants enter the combustion chamber, they are burning due to high velocity and temperature. Then there is a rapid increase in temperature and pressure in the combustion chamber, and afterward, they decrease over the nozzle's length. In this study, three configurations have been prepared in the design modular of ANSYS, a combined setup of the convergent–divergent nozzle with a combustion chamber with four inlets, six inlets, and one with increased combustion chamber length called a modified combustion chamber configuration. In this analysis, an investigation is performed to see the effect of multi‐inlet and increased length of the combustion chamber on the convergent–divergent nozzle's exit velocity. The results show that the configuration with six inlets modified combustion chamber has a 26.3% increase in velocity than six inlets and 38.6% higher exit velocity than four inlets convergent–divergent nozzle of the rocket engine.

The future of automobile internal combustion (IC) engine facing twin challenges due to emission norms and improving engine performance. Hence it is very important to identify some technique to reduce the emission level and also to improve the engine performance. Catalytic coating is one of the most suitable techniques for reduction of pollution level and increase the engine efficiency. In this paper, the investigations carried out in the single cylinder catalytic coated four stroke spark ignition (SI) engine is discussed in detail. The engine combustion chamber and piston crown were coated by copper (catalyst). The performance of catalytic coated engine various parameters such as torque, brake power at different engine speed conditions measured by using two wheeler chassis dynamometer. In this investigation the comparative study also were carried out for copper coated engine with conventional (Un-coated) SI engine and the results showed that copper coated engine has significant reduction of the carbon monoxide (CO), Hydrocarbon (HC), and Carbon dioxide (CO2) level compare to conventional engine (uncoated) emission levels.The future of automobile internal combustion (IC) engine facing twin challenges due to emission norms and improving engine performance. Hence it is very important to identify some technique to reduce the emission level and also to improve the engine performance. Catalytic coating is one of the most suitable techniques for reduction of pollution level and increase the engine efficiency. In this paper, the investigations carried out in the single cylinder catalytic coated four stroke spark ignition (SI) engine is discussed in detail. The engine combustion chamber and piston crown were coated by copper (catalyst). The performance of catalytic coated engine various parameters such as torque, brake power at different engine speed conditions measured by using two wheeler chassis dynamometer. In this investigation the comparative study also were carried out for copper coated engine with conventional (Un-coated) SI engine and the results showed that copper coated engine has significant reduction of the carbon mon...

<div class="htmlview paragraph">A heat release analysis model was developed for a two stroke spark ignition engine. The model was used to calculate the instantaneous heat release rates, mass fraction burned and temperature of the burnt and unburned mixture of the base engine and catalytic coated engine. The combustion chamber of the catalytic engine was coated with catalyst material like chromium by plasma spraying method. The experiments were conducted with various air-fuel ratios and heat release analysis was carried out for both base and catalytic coated engine. Engine cylinder pressure traces of 2000 continuous cycles were recorded using pc based data acquisition system. The average of these traces were calculated and used as input to the heat release model. The heat release rate from the single zone model was used to calculate combustion duration, start and end of combustion and burnt and unburned temperature from the two zone combustion model for the base and catalytic coated engine. The calculated combustion parameters indicate that the catalyst induces pre-flame reactions of fuel air mixture before combustion, which reduces delay period and increases the combustion rate. The combustion duration of catalyst engine was reduced by 8 degrees.</div>

<div class="section abstract"><div class="htmlview paragraph">In-cylinder fluid dynamics enhance performance and emission characteristics in internal combustion (IC) engines. Techniques such as helical ports, valve shrouding, masking, and modifications to piston profiles or vanes in ports are employed to achieve the desired in-cylinder flows in these engines. However, due to space constraints, modifications to the cylinder head are typically minimal. The literature suggests that introducing baffles into the combustion chamber of an IC engine can enhance in-cylinder flows, air-fuel mixing, and, subsequently, stratification. Studies have indicated that the height of the baffles plays a significant role in determining the level of improvement in in-cylinder flow and air-fuel mixing. Therefore, this study employs Computational fluid dynamics (CFD) analysis to investigate the impact of baffle height on in-cylinder flow and air-fuel mixing in a four-stroke, four-valve, spray-guided gasoline direct injection (GDI) engine. The maximum allowable baffle height is limited to the minimum distance between the piston and cylinder head surface when the piston is at the top dead centre (TDC). The analysis involves varying the baffle height from 1 mm to 3 mm. Additionally, a new discretisation scheme is introduced to assess the mixing level within the combustion chamber. The results indicate a significant influence of baffle height on in-cylinder flows. Notably, a 1 mm baffle height yields a flow and mixing pattern similar to that of the base engine without baffles. As the baffle height increases, the in-cylinder flows are altered, leading to the formation of multiple vortices due to the presence of baffles. Furthermore, an increase in baffle height enhances mixture stratification, confining more fuel toward the spark plug location.</div></div>

The reduction in environment pollutant emissions is one of the main challenges regarding ground transportation. Internal combustion engines, used especially in hybrid propulsion systems, may be a solution in the transition to fully electric cars. Therefore, more efficient engines in terms of fuel consumption, emission generation and power density must be developed. This paper presents research regarding the architecture of the combustion chamber of an internal combustion engine with opposed pistons. The aim of this research was to find a combustion chamber architecture that would enable the engine to perform close to the program target of: NOx < 3.5 g/kWh, smoke (FSN) < 1, specific fuel consumption (bsfc) < 198 g/kWh. Three variants of the combustion chamber’s architecture have been studied. After the experimental research, the conclusion was that none of them fully reached the target; however, significant improvements have been achieved compared with the starting point. As a result, further research needs to be carried out in order to reach and even exceed the target.

Flash‐boiling occurs when a fuel is injected into a combustion chamber where the ambient pressure is lower than the saturation pressure of the fuel. It has been known that flashing is a favorable mechanism for atomizing liquid fuels. On the other hand, alternative fuels, such as gaseous fuels and oxygenated fuels, are used to achieve low exhaust emissions in recent years. In general, most of these alternative fuels have high volatility and flash‐boiling takes place easily in the fuel spray when injected into the combustion chamber of an internal combustion engine under high pressure. In addition the multicomponent mixture of high‐ and low‐volatility fuels has been proposed in the previous study in order to control the spray and combustion processes in an internal combustion engine. It was found that the multicomponent fuel produces flash‐boiling with an increase in the initial fuel temperature. Therefore, it is important to investigate these flash‐boiling processes in fuel spray.In the present study, the submodels of a flash‐boiling spray are constructed. These submodels consider the bubble nucleation, growth, and disruption in the nozzle orifice and injected fuel droplets. The model is implemented in KIVA3V and the spray characteristics of multicomponent fuel with and without flashing are numerically investigated. In addition, these numerical results are compared with experimental data obtained in the previous study using a constant volume vessel. The flashing spray characteristics from numerical simulation qualitatively show good agreement with the experimental results. In particular, it is confirmed from both the numerical and experimental data that flash‐boiling effectively accelerates the atomization and vaporization of fuel droplets. This means that a lean homogeneous mixture can be quickly formed using flash‐boiling in the combustion chamber. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(5): 369–385, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20117

Gas flow behaviour is an extremely complicated question on internal combustion engine and plays a key role in air-fuel mixing performance. A proper mixture process significantly improves the combustion performance and thus enhances the engine efficiency. This study estimates the effect of different piston bowl depths on the flow field development inside the combustion chamber of a CNG engine using Ansys Fluent. The cold flow model was utilized without considering the combustion behaviour. The three-dimensional model was developed based on a single cylinder CNG converted engine. Four different bowl heights were applied while the compression ratio was maintained as the designed value of 10. The tumble and swirl as well as the turbulent flow pattern were investigated to consider the gas flow behaviour. The simulation results indicate that the tumble and swirl ratio increase with increasing of piston bowl depth. The case of bowl height 17 mm shows better flow behaviour and higher velocity for a good mixing performance as well as turbulence dissipation.

<div class="htmlview paragraph">The imaging of two–dimensional laser–induced fluorescence is used for simultaneous, multiple point visualization of OH radical concentration in the combustion chamber of a single cylinder internal combustion engine. Sheet illumination from the frequency doubled output of a Nd:YAG pumped dye laser is used to excite the fluorescence which is detected using an image–intensified Reticon diode array camera. The camera is interfaced to an IBM–PC AT microcomputer for data acquisition and processing. The laser and camera are synchronized with the crankshaft of the engine so that 2–D images of the OH fluorescence can be obtained at different times through the engine cycle. The OH fluorescence was measured over a 3 cm × 3 cm field of view with 0.3 mm spatial resolution and temporal resolution of < 10 ns. The measurements were made with propane/air mixtures at equivalence ratios of 0.8, 0.9, 1.0 and 1.1 at an engine speed of 600 rpm and at a chamber pressure of 1.34 ± .03 MPa. The OH fluorescence rises sharply through the flame front to a peak value and then decreases gradually in the post–flame gases.</div>

Time- and space-resolved quantitative LIF measurements of formaldehyde in a heavy-duty diesel engine

<div class="section abstract"><div class="htmlview paragraph">To explore the production and oxidation characteristics of soot in the flame of diesel jet under the condition equivalent to the direct injection diesel engine condition, the effect of three different important parameters (including injection pressure, injection duration, and oxygen concentration) are experimentally examined. For these purposes, a small CVCC (constant volume combustion chamber) with the volume of 60cc equivalent to the volume of combustion chamber of automotive diesel engine is used.</div><div class="htmlview paragraph">To obtain the experimental data of soot production and oxidation, in experiments, the ambient condition of temperature, pressure and oxygen concentration before injection timing are prepared by the combustion of lean hydrogen mixture (with help of 8 spark plugs) at a high temperature and pressure condition around 1000K and 4.5MPa. The common rail type injector with 8 injection holes for modern diesel engine is attached to this vessel. Injection pressures are set up at 80, 100, and 120 MPa. The effects of three important factors are analyzed including: (1) different injection pressures with constant injection mass; (2) different injection pressures with constant injection duration; (3) oxygen concentrations of 21% and 17% in volume. The optical window is attached on one side of this vessel and the full image of the spray flames can be visualized and recorded through this window by a high-speed color video camera. From the visualized color image of diesel flame, the flame temperature and the amount of soot inside the flame can be quantified by the two color method. This method is based on the theoretical principle that the light emission from the soot cloud is a thermal radiation of gray body which is a function of soot temperature and the KL factor, an index of the amount of soot.</div><div class="htmlview paragraph">The obtained results show that the injection duration and the injection rate are the dominant factors for heat release rate (HRR). On the contrary, within the experimental condition, the heat release rate is affected by both of the injection pressure and the oxygen concentration of ambient mainly at late combustion phase. The injection pressure and the injection duration give small effect on the level of flame temperature; however, the ambient oxygen concentration gives a large effect on the flame temperature.</div><div class="htmlview paragraph">Concerning the soot production and oxidation, all of the considered parameters have large effect. The interesting result is that the effect of injection pressure and ambient oxygen concentration on the maximum value of total KL factor is not so large. However, the soot production rate becomes lower as the decrease of injection pressure and as the decrease of ambient oxygen concentration, and results in the delayed arrival of the maximum total KL factor. Comparing with the HRR curve, it is revealed that the soot oxidation reaction is occurred under the very low HRR combustion in the case of low injection pressure and oxygen concentration condition.</div></div>

Experimental Investigation on Attenuation of Emission with Optimized LPG Jet Induction in a Dual Fuel Diesel Engine and Prediction by ANN Model