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The paper aims at documenting the material employed in 1942 for the fabrication of an exhaust valve for a Harley-Davidson WLA/WLC motorcycle and assesses the material features with modern steel standard specifications and treatment. Facing properties of the original historical parts of technical heritage objects according to modern standards is a rare discipline, as these objects are nowadays in collections of museums or private collectors and experimental instrumental analyses are strictly forbidden. In this case, a preserved accessible unused surplus replacement kit was studied. The microstructure was assessed by light optical and scanning electron microscopy, electron probe micro-analysis and by heat treatment–hardness correlation. It was found that the valve was made of Silchrome 1 steel in coherence with the X45CrSi9-3 steel modern material standard, but with a slightly higher content of phosphorus and sulfur. Microscopic observations and hardness profile testing suggested a tempered martensitic structure (sorbite) with very fine grains uniformly distributed in the valve and an even heat treatment. Heat treatment–hardness experimentation demonstrated that the original heat treatment cannot be achieved by the modern standard procedure. The tempering temperature was surprisingly deduced to be lower than the recommended one according to the modern standard, which contrasts with the service temperature indicated in the contemporary motorcycle mechanics handbook. [ABSTRACT FROM AUTHOR]

The start-up is a transient state of operation of an internal combustion engine during which many negative phenomena occur that affect the technical condition of the engine, its electrical equipment and the natural environment. The start-up process of an internal combustion engine is influenced by many factors, such as: technical condition of the starting system, technical condition of the engine, battery charge level, lubricant properties, engine standstill time, engine temperature, etc. Mechanical energy is required to start the engine, supplied by an electric starter by drives the engine’s crankshaft. Knowledge about the operating parameters of the electric starter during the start-up process is important not only for the user of the engine (vehicle driver), but above all for designers of modern combustion engine starting systems and service personnel. The paper presents the results of experimental tests of electrical parameters of the single-cylinder diesel engine start-up process at variable fuel injection parameters under ambient temperature conditions.

In the scope of the green energy and climatic changes waste poses as a great resource as an alternative fuel or source for their production. This helps to decrease the need for fossil resources, as well as diversify energy production. This kind of waste utilization and mitigation therefore directly fits into latest legislation and green initiatives. This paper focuses on the influence of five synthesis gases with relatively high heating values on the internal parameters of the internal combustion engine intended for cogeneration. Measurements show that proportion of the hydrogen in the mixture has indirect influence on the combustion duration and also maximal pressure rise rate. Interestingly hydrogen proportion in fuel showed no direct influence on the maximal in-cylinder pressure. Higher CO to CH4 ratio reduced burn time and increased maximal combustion pressure with slightly decreased performance. Concentration of CH4 directly influenced volumetric LHV value of the mixture with subsequent influence on the IMEP and engine effective torque. Generally, operation of the engine at full load at 1500 min−1 on chosen mixtures compared to the runs on methane showed decrease of engine torque output of up to 13.4% and increase of the hourly fuel consumption from 1.56 for pure methane to maximally 3.87 kg.h−1 for measured gases. Lastly, for one of the fuels erratic engine operation was observed.

The article discusses issues related to the behavior of powertrains understood as monuments of engineering art. The theoretical part analyzed the most important issues related to the maintenance and renovation of vehicles, their share in Poland in the age category, as well as the regulations regarding the classification of historic vehicles. The next part of the article presents the renovation process of two powertrains – the K-750 motorcycle and the Volkswagen Type 117 passenger car, along with a short production history. Then, recommended procedures for unique objects were discussed in the context of their state of preservation and occurrence based on the authors' experience. [ABSTRACT FROM AUTHOR]

Despite continuous work on new power systems for vehicles, machines, and devices, the combustion engine is still the dominant system. The operation of the combustion engine is initiated during the starting process using starting devices. The most common starting system used is the electric starter. The starting process of an internal combustion engine depends on the following factors: the technical condition of the starting system, technical condition of the engine, battery charge level, lubricating properties, engine standstill time, engine and ambient temperature, type of fuel, etc. This article presents the results of laboratory tests of the electrical parameters of the starting process of a single-cylinder compression–ignition engine with variable fuel injection parameters and ambient temperature conditions. It was confirmed that for the increased fuel dose FD2, higher values of the measured electrical parameters (Imax, Pmax, and Pmed) were obtained compared to the series of tests with the nominal fuel dose. Knowledge of the values of the electrical parameters of the starting process is important not only for the user (vehicle driver, agricultural machinery operator, etc.), but above all for designers of modern starting systems for combustion engines and service personnel. The obtained results of testing the electrical parameters of the combustion engine during start-up may be helpful in designing new drive systems supported by a compression–ignition combustion engine. [ABSTRACT FROM AUTHOR]

Plasma sprayed thermal barrier coatings (TBCs), applied in internal combustion engines, can have a profound impact on the apparent rate of heat release. Upon fuel jet contact with the piston wall, the heat loss seems to increase compared to an uncoated piston and combustion appears delayed. Permeable porosity of plasma sprayed TBCs is identified as one of the possible causes for this unwanted effect. In this article the impact of open porosity and sealing of the TBC surface are investigated with single cylinder engine experiments and with simulations. Based on the results, a mechanism is presented to explain the observations. [ABSTRACT FROM AUTHOR]

Relevance. The need to ensure safe working conditions in the working areas of underground mines. Stagnant zones with low air velocities can be formed in large section blind heading behind the ore bulk when ore is shipped by mining machines. There is a possibility of the formation of local gas accumulations and their abrupt removal later in such stagnant zones due to the unsteadiness of accumulation and transfer of gas impurities in a blind heading. A sharp removal of gas will lead to contamination of the load-haul-dump operators’ workplace. Aim. To identify removal of exhaust gases in large section blind headings in conditions of changing ore load size. Objects. Large section blind headings with of complex geometry. Methods. Three-dimensional numerical simulation of unsteady turbulent flow of a gas-air mixture in the Ansys CFX, visualization and analysis of simulation data in the Wolfram Mathematica. Results. The paper presents the results of mathematical modeling of ventilation of large section blind headings of complex geometry under conditions of changing ore load size formed during mining operations by the load-haul-dump machines with an internal combustion engine. It is shown that either a single vortex is formed that ventilates the blind headings space, or a stagnant zone behind the bulk ore, which is characterized by a relatively low intensity of mass transfer. Vortex formation depends on the height of the ore bulk. The authors have obtained the dependences of the change in the average concentration of exhaust gases at the outlet of the blind headings space on the operating time of the machine. They determined the dependence of the correction volume coefficient on the geometric parameters of the blind headings. An analytical model of the removal of gases from the blind headings space under conditions of changing bulk ore volume is obtained. The expression of increment in gas concentration on an operator’s workplace makes it possible to derive formula to find maximum time of load-haul dump operation in a stope such that gas concentration is never higher than maximum allowable concentration.

Biomass-fueled engines are a promising way to reduce the consumption of and dependence on fossil fuels. To create a working prototype, a detailed study of the thermodynamic cycle was developed. The dead volume was revealed to be the most limiting parameter for the engine efficiency. The cycle efficiency is reduced from 51.8% to 30.5% for the given example. The engine needs to be properly designed to minimize energy losses. In addition, the optimal compression ratio of the cycle is very low (about 3.5), losing energy in the exhaust gases and contributing to an inefficient engine. However, using a turbocharger can improve the cycle efficiency, combining the basic cycle with a Brayton cycle. Moreover, a two-stroke engine design is recommended for biomass-fueled engines. It allows minimization of the dead volume, is less sensitive to dirt, and avoids gas exchange with the combustion chamber during scavenging. Finally, the combustion chamber of the initial prototype was redesigned, based on the aforementioned improvements and allowing the successful start-up of the engine. This work demonstrates that biomass is a viable alternative to fossil fuels in applications where internal combustion engines are required. [ABSTRACT FROM AUTHOR]

Despite stricter emission controls and the planned reduction of newly sold Internal Combustion Engine (ICE) cars, adequate repairing and recycling of old ICE cars remains vital, reflected also by the recent EURO7 standard that explicitly refers to repairability. Digital Product Passports (DPPs) have gained attention as enablers of transparent and traceable value chains and improved product lifecycle management. While the focus has been put on creating DPPs for electric vehicle batteries, research on the potentials and requirements for DPPs for the ICE and its well-known components, like the exhaust gas turbocharger, does not exist. Thus, this study systematically investigates what information such DPP needs to contain to support value chain actors' sustainability/circularity-related decision-making. A mixed-method approach is applied. The Supply Chain Oriented Process to Identify Stakeholders (SCOPIS) method, as well as two expert workshops (N = 8 and N = 6) and an expert survey (N = 8) served for identifying the stakeholders and their most relevant information requirements. The results consist of a refined and prioritized list of information requirements, a conceptual model of a DPP for the turbocharger, and the presentation of two use cases: refurbishment and recycling. This contribution serves as the foundation for handling ICEs sustainably and circularly. [ABSTRACT FROM AUTHOR]

This scientific article presents an innovative concept of a hybrid power unit designed for ultralight aircraft, with the aim of improving energy efficiency and operational flexibility. As part of the development of the system, the construction of the combustion unit and the electric motor / generator, which are the key elements of this solution, was described. The advanced internal combustion engine controller and the bi-directional energy conversion converter have been developed and built to enable optimal cooperation of both energy sources. In order to carry out experimental research on the developed system, a special test stand was built on which a prototype drive unit was mounted. The results of the research include preliminary performance characteristics of the prototype drive unit and an analysis of the achievements that indicate the potential benefits of using such a hybrid drive unit. The article also summarizes the conclusions and recommendations for further work on improving this innovative solution. [ABSTRACT FROM AUTHOR]

The biggest problem facing internal combustion engine is the decrease of energy efficiency due to thermal losses, which causes an increase in fuel consumption and operating cost, as well as a large amount of burned gas released with major environmental problems resulting. In this context, we will focus in this work about improving the efficiency to minimize all these problems, for this we propose to minimize thermal losses through the use of FGM materials. In this context, a steady state heat conduction analysis of functionally graded cylinder is conducted to present the advantages of using of functionally graded materials over the metallic materials in structures that subject to thermal loads, the study is based on the comparison of temperature distribution along the radial direction of the cylinder between a pure metallic and two different functionally graded models, the geometric parameters and boundary conditions of the studied cylinder are considered similar to four-cylinder engine liners. The materials properties gradation is modelled using the power law distribution and the governing equation of heat conduction are solved analytically, the thermal dependency of the properties is supposed to be neglected, the presented results are obtained by a developed Matlab code and using Ansys software. [ABSTRACT FROM AUTHOR]

Hydrogen stands out as a compelling alternative to fossil fuels for combustion engines. Predictive combustion models are instrumental in developing hydrogen-fuelled engines. A fundamental metric of these models is the laminar burning velocity (LBV), which can be precisely determined through laminar flame propagation simulations. In this context, the selection of an appropriate combustion mechanism is critical. This paper aims to propose the appropriate combustion mechanism for calculating LBV in predictive combustion models of hydrogen-fuelled engines. 15 state-of-the-art combustion mechanisms were applied to reproduce the LBV measurements in engine-like conditions, especially considering the application of lean combustion and water injection. The FFCM 1.0 mechanism was identified from them and further optimised to improve its prediction accuracy at elevated pressures for the lean mixture. The maximum deviation of LBV was reduced from 17.6 % to 8.7 % by this optimisation, in comparison to 10.5 % for its closest competitor mechanism, ELTE (Varga et al., 2015). • 15 combustion mechanisms were selected as the candidates for optimisation. • Test cases consider applications of lean combustion and water injection. • Many mechanisms predict laminar burning velocities at elevated pressure inadequately. • FFCM 1.0 mechanism was optimised to a new mechanism for modelling H2-fuelled engines. • Prediction errors of laminar burning velocity by the new mechanism are within 8.7 %. [ABSTRACT FROM AUTHOR]

The first step to achieving an energy transition is partially substituting fossil fuels with other more environmentally friendly alternatives, such as hydrogen gas. The current research aims to evaluate the influence of hydrogen in a diesel generator fueled with rice bran biodiesel. The above encourages the use of hydrogen and biodiesel production from residual raw material. For the development of the research, a diesel engine bench was used, which operated in five load conditions: 20 %, 40 %, 60 %, 80 %, and 100 %, and was fed with three fuels: −100 %, RB-10 %, and RB-10 % + H2(30 %). The results show that the mixture RB-10 % + H2(30 %) causes a 3.14 % reduction in BSFC and a 3.26 % increase in energy conversion efficiency. In addition, it is observed that a 9.90 %, 12.57 %, and 10.99 % decrease in HC, CO, and smoke opacity emissions compared to pure diesel. On the other hand, the mixture RB-10 % + H2(30 %) reduces by 4.44 %, 5.07 %, and 7.06 % the environmental, social, and ecological impact due to CO2, HC, and CO emissions, as well as a 3.93 % reduction in engine operating cost compared to RB-10 % biodiesel. In general, hydrogen injection is a promising alternative to promote the use of rice bran biodiesel due to its increased performance characteristics and reduced pollutant emissions without the need to modify the engine.

Since control instructions are the fundamental component of thermal power generation, the quality and effectiveness of implementation directly affect the efficiency of the energy system. In order to improve the efficiency of internal combustion engine control, an optimization method of internal combustion engine control based on enhanced clustering algorithm and swarm intelligence optimization algorithm is proposed. The process simplifies the main structure of the gas turbine, divides the combustion engine model into multi-input single-output systems, and introduces the artificial bee colony algorithm to optimize the parameters. A new nectar search formula is constructed by using the global optimal nectar, and the control parameters are calculated by fuzzy logic clustering. The experimental results showed that the modeling error of the load model of internal combustion engine was in the range of −0.47 MW $\sim ~0.51$ MW. When the training iteration speed was tested, the loss value of the research method dropped rapidly in the first 10 iterations. When analyzing the change of the control quantity during load change, if the exhaust flow rate was taken as the control quantity, the control results of the research method was always kept within 5lbm/s error. It demonstrates that this research method can effectively improve the running quality of the internal combustion engine and has a good running efficiency. The research can provide certain technical reference for gas turbine control in thermal power generation.

Changing the ignition advance angle has a significant impact on the performance of a combustion engine. Optimization of ignition advance angle is a major task of adjusting the engine concerning emission standards, fuel consumption, torque value, etc. The results of the research showed that the process of optimizing the ignition advance curve can noticeably increase engine efficiency, as well as torque and power output from the engine while reducing fuel consumption as a result of lower indications of the air flow mass per second from MAF sensor (mass air flow sensor). The highest impact of the ignition advanced angle modifications can be seen in the area of the highest volumetric efficiency of the tested combustion engine. Almost no impact is observed within high engine speed levels. Simultaneously increasing engine load and rotation speed increases the possibility of engine knocking, which has a devastating effect on engine durability. [ABSTRACT FROM AUTHOR]

The paper presents an analysis of the experimental results of direct hydrogen injection in a dual-fuel diesel engine. The test object is a four-cylinder, four-stroke ADCR engine. The parameters like: indicated mean effective pressure, peak pressure, angle of maximum pressure and released heat were analyzed. Statistical analysis of the obtained results was carried out for each cylinder separately for four different hydrogen doses. Both early and late direct hydrogen injection were analyzed. The significance of the differences for each of the analyzed parameters and type of injection was determined. The stability of the combustion process was evaluated using the coefficient of variation CoV(IMEP). [ABSTRACT FROM AUTHOR]

Vehicle coolant is one of the most important operating fluids. Along with changes in the design of engines, the composition of the coolant has also changed. The main function of the coolant is heat transfer (HT). It absorbs up to one-third of the heat energy generated by the engine. The coolant is also responsible for protecting the cooling system from damage caused by corrosion, scaling and deposits. The unfavorable working environment of the engine is also affected by smaller capacities of the cooling systems (CSs) of the drive units, extreme temperatures and increased pressure in the CS, enhancing the importance of the fluid composition. The coolant must be replaced every three years or 100,000 kilometers or every five years or 250,000 kilometers with the Organic Acid Technology (OAT). It is worth remembering that coolant of unknown composition or low quality used for a long time can expose the system to engine overheating, corrosion, deposits and restriction of liquid flow. This can lead to engine failure, in extreme cases even engine seizure. Currently, many types of fluids, including nanocoolants with different compositions, are available on the cooling market. The article presents these fluids, describe the most common failures of CSs, present the currently used methods of fluid replacement in the engine and proposes an innovative method based on the pressure method, which allows both replacing the fluid in the entire system and cleaning it. [ABSTRACT FROM AUTHOR]

Adopting carbon-neutral fuels is paramount to aligning internal combustion engines with global efforts to mitigate the impact of global warming. Hydrogen offers distinct advantages over other renewable fuels owing to its superior combustion properties. This comprehensive review explores three fuel injection systems suitable for using hydrogen as a fuel: mixers, port injections, and direct injections. Subsequently, we examined the emission characteristics of hydrogen internal combustion engines (HICE). Although nitric oxides (NOx) is the major emission from HICE, small quantities of hydrocarbon, CO, and CO2 should be expected due to engine oil burn. Moreover, we provide a concise overview of aftertreatment options, including urea-based selective catalytic reduction (SCR) and hydrogen-assisted SCR (H2-SCR). [ABSTRACT FROM AUTHOR]

Biogas merupakan energi alternatif degradasi produk akhir pencernaan hewan ternak (sapi) dalam keadaan anaerobik oleh bakteri metanogen yang berupa gas metana dan semacamnya. Biogas menjadi salah satu bahan bakar alternatif yang bisa dimanfaatkan menjadi energi listrik dengan memodifikasi sistem karbulasi pada generator motor bakar. Metode yang digunakan yaitu eksperimental, pertama yaitu pengujian prestasi motor bakar dengan metode variasi pengereman poros (prony brake) yaitu 1000 rpm; 1500 rpm; 2000 rpm; 2500 rpm; dan 3000 rpm. Pengujian kedua yaitu pengujian kinerja generator yaitu pada pembebanan listrik 112 watt; 200 watt; 312 watt; 482 watt; dan 570 watt. Nilai torsi dan daya maksimum motor bakar terjadi saat menggunakan bahan bakar biogas pada putaran 2500 rpm yaitu 37.8 Nm dan 3.91 kW jika dibandingkan dengan pertalite sebesar 37.67 Nm dan 3.86 kW. Konsumsi bahan bakar spesifik (SFC) biogas lebih hemat dari pertalite yaitu sebesar 0.000015 kg/kW.s dengan 0.000069 kg/kW.s. Efisiensi termal maksimum menggunakan biogas lebih tinggi daripada pertalite yaitu 36.08% dengan 32.95%. Suhu gas buang dari bahan bakar biogas lebih tinggi dari bahan bakar pertalite. Pada pengujian generator, penggunaan biogas memiliki tingkat efektifitas lebih tinggi dibanding pertalite dan telah memenuhi standar listrik nasional.

This paper presents a method for the precise diagnosis of a diesel engine in an agricultural tractor based on the analysis of efficiency changes and parameters characterizing the process of fuel-air mixture preparation. We proposed that the technical condition be identified based on available data from the engine controller, as this enables the implementation of precise online diagnostics of an agricultural tractor. The method was verified using the original cycle, during which we simulated several engine defects leading to a change in conditions and quality of the processes of creating and burning the fuel/air/flue gas mixture. In the paper, we justified the selection of the points at which the engine parameters were measured, as they provide the most information and allow for efficient identification of damage. These results indicate the possibility of damage identification without the use of the diagnostic cycle in the operation of operator-driven vehicles and autonomous vehicles.

The article presents a method of determining the characteristics of exhaust emissions and fuel mass consumption in real driving conditions based on a single test using the Monte Carlo method. The exhaust emission characteristics used are the relations between the emissions and the average vehicle speed, and the characteristic of the fuel mass consumption is the dependence of the fuel mass consumption at the average vehicle speed. The results of empirical research of a passenger car with a spark-ignition engine in the RDE test were used. The use of the Monte Carlo method made it possible to select the initial and final moments of averaging the process values, thanks to which it was possible to determine the discrete values of the characteristics for various values of average vehicle speeds. The determined discrete characteristics of the particulate mass and number emissions and fuel mass consumption relative to the average vehicle speed were approximated by polynomial functions of the second and third degree. The determined discrete characteristics, presented as sets of points, were characterized by a relatively small dis-persion in relation to their polynomial approximations. The average relative deviation of the points of discrete characteristics from the value of the polynomial was in most cases small less than 4%, only in the case of the number of particles emitted deviated from this, as the average relative deviation of the measured points from the determined polynomial was nearly 14%. Combined with the results of RDE empirical studies, the Monte Carlo method proved to be an effective method for determining the characteristics of exhaust emissions, measured in real vehicle operating conditions. The main advantage of the proposed method was a significant reduction in the actual workload necessary to carry out the empirical research where it became possible to determine the charac-teristics in a large range of vehicle average speed values with just one drive test. Using standard methods of meas-uring this type of data, it would be necessary to conduct multiple tests, driving at different average vehicle speeds.

The article analyzes and evaluates costs, transport time and CO2 emissions by selected vans. The research was carried out on the example of three models of Iveco Daily vehicles powered by: diesel oil, electricity and compressed natural gas (CNG). The result of the research presented in the article is the determination of the operating costs of vehicles powered by various energy sources and the level of CO2 emissions. The comparative analysis was carried out on real data for the established transport task. Vehicles with engines powered by compressed natural gas are characterized by the highest savings in terms of transport costs. As the authors pointed out, this may be due to the fact that this type of engines, despite the low interest of buyers at the moment, may gain much more popularity in the future. On the other hand, in relation to vehicles with electric motors, the cost of transport is the highest, which means that this type of technology is ineffective in relation to long-distance transport. [ABSTRACT FROM AUTHOR]

The diffusion kinetics theory of cleaning assemblies such as combustion engines with flushing oil has been introduced. Evolution of tar deposits on the engine surfaces and in the lube system has been described through the erosion dynamics. The time-dependent concentration pattern related to hydrodynamic (sub)layers around the tar deposit has been uncovered. Nonlinear equations explaining the experimentally observed dependences for scouring the contaminants off with the oil have been derived and indicate the power law in time. For reference purposes, a similar analysis based on formal chemical kinetics has been accomplished. Factors and scouring parameters for the favor of either mechanism have been discussed. Any preference for either diffusion or chemical kinetics should be based on a careful selection of washing agents in the flushing oil. Future directions of studies are proposed. [ABSTRACT FROM AUTHOR]

The flow of exhaust gases is the source of many physical processes, including thermal, acoustic, mechanical and chemical phenomena with high dynamics of changes. The study analyzes the impact of the entire structure of the exhaust system on the formation of acoustic energy, determining the transmission loss characteristics of its individual components and the entire system. On the example of a structure based on a proprietary solution of an adjustable reactive muffler, the possibilities of shaping the flow of acoustic waves in the process of designing and selecting exhaust systems for internal combustion engines were determined. The study was carried out with the use of the CFD method and a specialized package for advanced simulations AVL AST.

Despite continuous work on new power systems for vehicles, machines, and devices, the combustion engine is still the dominant system. The operation of the combustion engine is initiated during the starting process using starting devices. The most common starting system used is the electric starter. The starting process of an internal combustion engine depends on the following factors: the technical condition of the starting system, technical condition of the engine, battery charge level, lubricating properties, engine standstill time, engine and ambient temperature, type of fuel, etc. This article presents the results of laboratory tests of the electrical parameters of the starting process of a single-cylinder compression–ignition engine with variable fuel injection parameters and ambient temperature conditions. It was confirmed that for the increased fuel dose FD2, higher values of the measured electrical parameters (Imax, Pmax, and Pmed) were obtained compared to the series of tests with the nominal fuel dose. Knowledge of the values of the electrical parameters of the starting process is important not only for the user (vehicle driver, agricultural machinery operator, etc.), but above all for designers of modern starting systems for combustion engines and service personnel. The obtained results of testing the electrical parameters of the combustion engine during start-up may be helpful in designing new drive systems supported by a compression–ignition combustion engine.

Biomass-fueled engines are a promising way to reduce the consumption of and dependence on fossil fuels. To create a working prototype, a detailed study of the thermodynamic cycle was developed. The dead volume was revealed to be the most limiting parameter for the engine efficiency. The cycle efficiency is reduced from 51.8% to 30.5% for the given example. The engine needs to be properly designed to minimize energy losses. In addition, the optimal compression ratio of the cycle is very low (about 3.5), losing energy in the exhaust gases and contributing to an inefficient engine. However, using a turbocharger can improve the cycle efficiency, combining the basic cycle with a Brayton cycle. Moreover, a two-stroke engine design is recommended for biomass-fueled engines. It allows minimization of the dead volume, is less sensitive to dirt, and avoids gas exchange with the combustion chamber during scavenging. Finally, the combustion chamber of the initial prototype was redesigned, based on the aforementioned improvements and allowing the successful start-up of the engine. This work demonstrates that biomass is a viable alternative to fossil fuels in applications where internal combustion engines are required.

The article presents the concept of a hybrid propulsion unit for ultralight aircraft. A combustion unit and an electric motor/generator were presented. As part of the research, a dedicated combustion engine controller and a two-way converter for energy conversion were built. The prototype drive unit was installed on a test stand and its initial characteristics were determined. The results of research and conclusions related to the construction of a hybrid drive unit are presented.

The present study was focused on the combustion engine with a variable compression ratio (VCR), namely the four-stroke air-cooled engine with the active combustion chamber (ACC). An indicated pressure, torque, power, and specific fuel consumption of that engine were investigated experimentally as a goal of the present study. Experiments were conducted using two versions of an engine. Two parameters particularly influencing the ACC engine performance including the maximum compression ratio CRmax and the indicator γfm determining the correct operation of the ACC system, were described. It was found that the ACC engine allowed avoiding detonation combustion without changing the amount and composition of the combustible mixture, and even without delaying the ignition advance angle. In addition, the possible range of control of the combustion process allowed the ACC engine to operate with different types of hydrocarbon fuels, for example, in the form of petrol with various alcohol admixtures. The very intense flow of the combustible mixture inside the cylinder of the ACC engine allowed describing the combustion in the ACC engine with zero-dimensional mathematical models with the dual Vibe function providing the proper characterization of the heat release process. The use of very high maximum compression ratios allows the ACC engine to operate to a certain extent as a Homogeneous Charge Compression Ignition (HCCI) engine with high lambda coefficients. [ABSTRACT FROM AUTHOR]

Homogenous charge compression ignition (HCCI) combustion can significantly reduce automotive pollution and increase the thermal efficiency of the engine. However, combustion phasing control is a major challenge in HCCI engines due to severe cyclic combustion variations. This study investigates the cyclic combustion dynamics of the HCCI engine using nonlinear dynamic methods such as return maps, recurrence plots (RPs), and recurrence quantitative analysis (RQA). Combustion stability and cyclic variations of HCCI combustion parameters were investigated on a modified four-stroke diesel engine. The experiments were conducted by varying relative air-fuel ratios (λ) and intake air temperatures ( T i ) at two engine speeds. In-cylinder pressure data of 2000 consecutive engine combustion cycles is logged for each test condition. In this study, deterministic characteristics of combustion phasing (CA50) and crank angle position of maximum cylinder pressure ( θ P max ) are investigated and compared by employing nonlinear dynamical methods. Return maps revealed that θ P max is having distinct and more frequently observed deterministic characteristics in comparison to CA50. Patterns in RPs showed a more persistent and sudden change in the combustion dynamics at higher engine speeds. Recurrence plot-based analysis found the existence of deterministic features in the combustion dynamics irrespective of the operating conditions. It was found using RQA parameters that the deterministic nature becomes stronger with a decrease in T i and any deviation in intermediate values of λ. Additionally, RQA measures advocate that CA50 has more deterministic characteristics at higher engine speed while θ P max at lower engine speed. Strong coupling and synchronization between θ P max and CA50 is indicated by cross-recurrence plots and CPR index when engine operated with a comparatively richer mixture. [ABSTRACT FROM AUTHOR]

The process of transesterification is slow due to the low solubility of triglycerides in methanol. The limitation of mass transfer can be overcome by adding a co-solvent. Co-solvent FAME is the right choice because it is the product of the reaction itself so that it does not require a separation process. The purpose of this study was to examine the use of FAME as a co-solvent in the transesterification of palm oil and its application to the combustion engine. The operating conditions were palm oil mass of 250 gr, NaOH catalyst 1.2% wt, stirring speed 100 rpm, reaction temperature 70oC, ratio molar of oil:methanol =1:6, reaction time (5,10,15,20,25,30 minutes), and co-solvent (0,5,10,15% wt). After the optimum conditions are obtained, the next step is to make biodiesel on a semi pilot plant scale. Oil, methanol, NaOH and co-solvent were put into a stirred reactor and heated at a reaction temperature of 70⁰C. After the reaction is complete then it is flowed into the separator for separation by adding hot water to form 2 layers. The top layer is biodiesel which was analyzed and performance test on the combustion engine. The optimum condition of the process is a reaction time of 10 minutes and the addition of 10% co-solvent, with a yield of 76.7783%. The results of the analysis of SNI 7182:2012 states that biodiesel meets almost all requirements. From the biodiesel performance test on the combustion engine, B10 got quite satisfactory results for the torque and opacity test parameters.

The most common fuel used for powering compression ignition engines is diesel, whose main components are petroleum products. The constantly growing energy demand involves the implementation of new technical solutions and applying alternative fuels, including renewable ones, such as rapeseed oil, sunflower oil, peanut oil, and animal fats. The most commonly used biofuels are those obtained from chemically processed rapeseeds (transesterification) to provide them with physical–chemical properties similar to diesel fuel. The study presents the results of tests of a power unit fueled with different mixtures of diesel oil and fatty acid methyl esters. The experiment was carried out for a compression ignition engine of 81 kW power with direct fuel injection. Performance parameters of the vehicle power unit and its computer software were modified for the needs of the tests. Those modifications involved increasing the fuel dose and the fuel injection pressure. The test results were statistically analyzed. Based on the results, a simulation of power and torque was performed, depending on the vehicle computer system adjustment and the fuel mixture used. A simulation of the vehicle movement in a non-homogeneous environment (variable road conditions) was performed concerning the vehicle motion kinematics. The simulations were carried out in a V-SIM 5.0 program. The simulation was performed at five speeds, respectively: 0 km/h, 25 km/h, 50 km/h, 75 km/h, and 100 km/h. The simulation made it possible to determine speed, acceleration, time, and distance. The analysis shows that the highest acceleration of 3 m/s2 was obtained for the BIO50 mixture, regulation V. The longest road section needed to achieve the maximum speed (100 km/h) was recorded for the BIO10 mixture, regulation II. The simulation duration ranged from 17.9 s to 17.74 s, depending on the adopted variant. [ABSTRACT FROM AUTHOR]

This paper presents a method for the precise diagnosis of a diesel engine in an agricultural tractor based on the analysis of efficiency changes and parameters characterizing the process of fuel-air mixture preparation. We proposed that the technical condition be identified based on available data from the engine controller, as this enables the implementation of precise online diagnostics of an agricultural tractor. The method was verified using the original cycle, during which we simulated several engine defects leading to a change in conditions and quality of the processes of creating and burning the fuel/air/flue gas mixture. In the paper, we justified the selection of the points at which the engine parameters were measured, as they provide the most information and allow for efficient identification of damage. These results indicate the possibility of damage identification without the use of the diagnostic cycle in the operation of operator-driven vehicles and autonomous vehicles. [ABSTRACT FROM AUTHOR]

The flow of exhaust gases is the source of many physical processes, including thermal, acoustic, mechanical and chemical phenomena with high dynamics of changes. The study analyzes the impact of the entire structure of the exhaust system on the formation of acoustic energy, determining the transmission loss characteristics of its individual components and the entire system. On the example of a structure based on a proprietary solution of an adjustable reactive muffler, the possibilities of shaping the flow of acoustic waves in the process of designing and selecting exhaust systems for internal combustion engines were determined. The study was carried out with the use of the CFD method and a specialized package for advanced simulations AVL AST. [ABSTRACT FROM AUTHOR]

This article presents the results of research into the causes of the wear of the piston pin mounted in piston bosses by means of a hinge joint and in the connecting rod small end by means of the thermocompression bond. Changes in geometry and in the pin-top surface structure, which are caused by the mutual influence of the mating surfaces in variable lubrication conditions, are presented. The progress of scuffing as a result of insufficient lubrication of the mating elements or oil film breaking is demonstrated. The state of destruction was confirmed by the results of surface roughness measurements showing the formation of build-ups. The loss of the thermocompression bond surface, caused by the penetration of sintered engine oil fractions containing biofuel additive components and spent engine oil improver packages, was noted. The progressing forms of wear are the cause of engine failures due to the pin movement towards the cylinder wall, and due to boss breakage in the piston. [ABSTRACT FROM AUTHOR]

Featured Application: The flow characteristics of the injectors from gas-fueling systems of automobile engines under pulsating flow were determined. The approximating equations and the results of statistical treatment are presented. Possible causes of discrepancies by the indirect method are given and verified. The results are applicable to the calculation of fuel systems, as well as whole internal combustion engines and the practical implementation of component selection. Despite the growing share of electrically powered vehicles, internal combustion engines are still one of the primary sources of propulsion in transportation. One way to decarbonize engines is to use alternative fuels, where liquefied petroleum gas (LPG) accounts for a large share. Popular car gas systems are LPG indirect vapor phase injection systems, in which the low-pressure gas-phase injector is the actuator. The purpose of the research and analysis presented in this paper is to determine the flow characteristics of three injectors that are structurally different depending on the diameter of the outlet nozzle bore. The tests are conducted, which is new, with pulsed operation of the injector, which, as it turned out, helps explain the discrepancies found. The obtained characteristics are fitted with a polynomial of the second degree, obtaining high-quality indices. In the group of three tested injectors, the average values of volumetric flow rate decreases relative to the maximum by 19.6 and 35.8%. Differences in opening times of 29.3 and 36.6%, respectively, are cited as one of the main reasons for this. Closing times are similar to each other. In addition, the injector with the highest volumetric flow rate and the shortest opening time obtains 1.8 and 9.94% lower average cycle pressures measured at the outlet of the injector nozzle. The differences in opening times and average cycle pressures are considered as possible reasons for the differences in flow characteristics. The obtained characteristics are applicable to engine conversions and calculations. [ABSTRACT FROM AUTHOR]

This paper presents the research results for a diesel and hydrogen fueled engine. The research object is a four-cylinder, four-stroke ADCR engine with a displacement of 2,636 cm3. In the experiments, glow plugs were replaced with compressed hydrogen injectors and a special adapter. Hydrogen was supplied directly into a combustion chamber using a test injector. A hydrogen dose in the tests was changed at selected test points and ranged from 0 to 160 dm3/min. The research were conducted at 1,500 rpm. A hydrogen injection start angle and maximum hydrogen dose were specified from the preliminary experiments. The following parameters were analyzed: indicated mean effective pressure, maximum pressure, crank angle of maximum cylinder pressure occurrence and heat release. The obtained results were statistically analyzed. The conducted analysis focused on determining whether there are significant differences between early and late injection and how these changes affect the measured parameters.

This paper presents the air-path health management strategy with the ability to estimate the mass-flows and mitigate (adapt to) the air-path faults in the exhaust system of a heavy-duty diesel combustion engine equipped with a twin-scroll turbine. Based on the engine component models applied in the quasi-steady-state mass-balancing approach, two main engine mass-flow quantities are estimated: the Air mass-flow (AMF) and the Exhaust gas recirculation (EGR) mass-flow. The health management system is monitoring for three kinds of air-path faults that can occur through the combustion engine operation, related either to the after-treatment system, EGR valve, or to the turbine balance valve hardware. For each fault, a fault-mitigation strategy based on in-observer-reconfigurable mass-balance equations with excluded faulty component model and utilized exhaust pressure sensor is proposed. The applied observer is using the iterated Kalman filter (IKF) as the core fault mitigating solver for the quasi-steady-state mass-balancing problem. It is further demonstrated how the individual faults are robustly isolated using the Sequential Probability Ratio Test (SPRT). The strategy and results are validated using the test cycle driving data.

Climate change and the depletion of fossil fuels make it urgent to find an alternative to oil-based fuels, especially in machines powered by internal combustion engines. Biomass is currently a poorly used source of energy and meets the necessary conditions to replace a large part of oil-based fuels. However, current engines cannot burn solid biomass and a specific engine needs to be developed. This work proposes the thermodynamic cycle of a biomass-fueled internal combustion engine. The cycle is significantly different from the Otto cycle, since compression and heat absorption occur simultaneously, in a single stage. Since it is not possible to find a function that relates pressure to volume at this stage, an approximate method is proposed to solve the cycle without resorting to numerical methods. The results show that the maximum pressure and temperature of a biomass-fueled engine cycle are somewhat higher than those of the equivalent Otto cycle. However, more significantly, the cycle efficiency does not increase continuously with the compression ratio. There is an optimum compression ratio value for which the cycle efficiency is at its maximum. This fact will condition the design of the motors. [ABSTRACT FROM AUTHOR]

The use of hydrogen as a fuel for an internal combustion engines has caused many problems for years, the most significant of which seems to be the excessive emission of nitrogen oxides and the tendency to knock combustion. In order to ensure better control of the combustion process in a internal combustion engine powered by hydrogen, it has been proposed to use a split combustion chamber solution. Following paper contains a description of a hydrogen combustion system that includes an analysis of possible technical solutions. The considerations take into account the issues of the dual nature of hydrogen knocking and the problem of burning a stratified charge of a hydrogen-air mixture in a cylinder.

The paper describes the method of determination of exhaust emission characteristics from a vehicle engine based on the results obtained in a driving test simulated on an engine dynamometer. These characteristics are the relations between the specific distance emissions and the zero-dimensional characteristics of the process of vehicle velocity: the average velocity value and the average value of the absolute value of the product of vehicle velocity and acceleration. The exhaust emission characteristics are used to simulate the emissions from vehicles operating in different types of traffic conditions. The engine operating states in the engine dynamometer tests were determined by the operating conditions of the vehicle during the test. The authors applied the Monte Carlo method in order to determine the characteristics of different values of the zero-dimensional characteristics of the vehicle velocity process. This enabled the determination of the characteristics based on the test results from a single realization of the process of vehicle velocity. Additionally, the developed method allowed a replacement of the empirical research on the chassis dynamometer with the one performed on the engine dynamometer. The obtained exhaust emission characteristics are in line with the characteristics obtained on the chassis dynamometer in multiple tests.

Contemporary operation-related requirements for combustion engines force the necessity of ongoing assessment of their in operation technical condition (e.g. marine engines). The engine efficiency and durability depend on a variety of parameters. One of them is valve clearance. As has been proven in the paper, the assessment of the valve clearance can be based on vibration signals, which is not a problem in terms of signal measurement and processing and is not invasive into the engine structure. The authors described the experimental research aiming at providing information necessary to develop and validate the proposed method. Active experiments were used with the task of valve clearance and registration of vibrations using a three-axis transducer placed on the engine cylinder head. The tests were carried out during various operating conditions of the engine set by 5 rotational speeds and 5 load conditions. In order to extract the training examples, fragments of the signal related to the closing of individual valves were divided into 11 shorter portions. From each of them, an effective value of the signal was determined. Obtained total 32054 training vectors for each valve related to 4 classes of valve clearance including very sensitive clearance above 0.8 mm associat-ed with high dynamic interactions in cylinder head. In the paper, the authors propose to use a convolutional network CNN to assess the correct engine valve clearance. The obtained results were compared with other methods of machine learning (pattern recognition network, random forest). Finally, using CNN the valve clearance class identification error was less than 1% for the intake valve and less than 3.5% for the exhaust valve. Developed method replaces the existing standard methods based on FFT and STFT combined with regression calculation where approximation error is up to 10%. Such results are more useful for further studies related not only to classification, but also to the prediction of the valve clearance condition in real engine operations.

Internal combustion engines represent the largest share of motor vehicle propulsion types. Despite the introduction of alternative drives (hybrid and electric), combustion engines will continue to be the main factor in the development of transport. Therefore, work related to their technological development and reduction of their harmful effects on human health and the environment is required. The development of internal combustion engines can be seen in two directions: technological changes resulting in increased efficiency of such engines and the second direction connected with limi-tation of exhaust gas emission. The present work is included in the second direction of research interests and concerns the analysis of various operating conditions of internal combustion engines. The operating states, both static and dynamic, determine the operational properties of internal combustion engines, such as fuel and energy consumption as well as pollutant emissions. So far, such operating conditions have only been mapped on a chassis dynamometer in various homologation tests. The course of the type approval test was known and the conditions of measurement were also known, which made it impossible to introduce a random factor into such tests. Currently, these properties are determined in tests performed in real vehicle operating conditions – RDE (Real Driving Emissions). Such tests are representing real operating conditions of motor vehicles. Limitations for performing tests in real traffic conditions are, apart from formal requirements concerning the duration and distance of individual parts, the dynamic conditions of vehicles determined by the speed and acceleration of the vehicle. The study analyzed the properties of vehicle speed processes and engine operating states in the RDE test, taking into account its individual phases – driving in urban, rural and motorway conditions. Engine operation states are the processes of the engine rotational speed and its rela-tive torque. It was found that the dynamic properties of the vehicle speed process are much more significant than the engine operating states. It was also found that the road emission of pollutants in the RDE test, which is the property of vehicles measured in the test, the motorway phase properties have greatest impact.