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The modern solution of two-stage combustion, namely the Turbulent Jet Ignition, enables the combustion of ultra-lean mixtures. Thanks to this solution, it became possible to reduce fuel consumption and, at the same time, to increase the combustion process indicators (including the overall combustion system efficiency). The article presents the results of numerical tests of a heavy-duty engine equipped with the TJI system running on hydrogen fuel. The operating conditions of the Heavy-Duty engine at n = 1500 rpm and IMEP = 10 bar with a prechamber with 7 holes were analyzed. The research was conducted with the use of lean mixtures (global lambda ca. 2 or more). The AVL FIRE software was used to perform the analysis of different fuel doses delivered to the main chamber, with a constant global excess air coefficient value. Increasing the proportion of hydrogen in the pre-chamber resulted in its reduction in the main chamber.

Hybrid powertrains are replacing conventional combustion drives at an accelerating rate, while offering a reduction in fuel consumption and toxic exhaust emissions. The large share of hybrid solutions in engine vehicles has been observed for the compact class and in SUVs. The Authors of this study proposed an energy flow assessment in the hybrid powertrain system of an SUV in various driving conditions: urban, extra-urban and motorway. The tests were performed in accordance with the stipulations of the RDC test conditions and its requirements. The tests were carried out on a Toyota RAV4 HEV equipped with a 2.5 dm3 engine in a hybrid drive system along with Li-Ion batteries, which had an energy capacity of 1.11 kWh (4.3 Ah). The research was carried out on an urban route in Poznan as well as in its vicinity using three drive modes of the drive system: Eco, Normal and Sport.

The paper concerns the analysis of the combustion and exhaust emission phenomena in a direct gasoline dual injection system of a SI engine for various symmetrical injector placement parameters in the combustion chamber. Achieving a good combustion process is shaped by the direct fuel injection process, whose parameters vary. The novel direct injection system, which deploys two direct injectors mounted symmetrically, was subjected to this simulative research. This article focuses on the aspect of spatial and angular position of injectors in order to perform injection and achieve fuel combustion. The injector's pseudo-optimal location has been presented along with several changed positions (3 values of injector inset: 0, 1 and 2 mm, 3 values of injector distance from the cylinder axis: 16, 17, 18 mm and 3 values of angle between injector and the cylinder axis: 42.5, 45 and 47.5 degrees - 27 combinations altogether).

Energy flow in vehicles with hybrid propulsion systems depends primarily on the drive system design. The full hybrid propulsion system (series-parallel) enables differentiated energy flow management using different drive system operating conditions and energy recovery methods. The article attempts to estimate the energy differences resulting from this type of a system operating in two different modes: mode D - normal driving and mode B - forcing partial use of engine braking. Using these two driving modes in the real drive test, the energy flow characteristics of the vehicle were determined. Different operating conditions of the internal combustion engine and drive system in both modes allowed for the energy consumption during driving tests to be assessed.

The paper presents the thermodynamic analysis of the engine supplied with small and large diesel fuel doses while increasing natural gas quantity. The paper presents changes in the combustion process thermodynamic indexes and changes in the exhaust gas emissions for dynamically increased share of the gaseous fuel. The cylinder pressure history was subject to thermodynamic analysis, . based on which the mean indicated pressure, the heat release rate, the quantity of heat released as well as the pressure rate increase after self-ignition were determined. These parameters were also referred to the subsequent engine operation cycles by specifying the scope of the change per cycle. The relationship between the engine load and the start, the center and the end of combustion while increasing the gas amount supplied to the cylinder was indicated.

The paper discusses the results of investigations into fuel atomization with the use of two high-pressure angularly arranged injectors fitted in a combustion of constant volume chamber. Using two Direct Injection injectors is a new conception, which was not applied yet. Nowadays, the conceptions where two injectors are used, one in direct injection and one in port injection are used. It is expected, that new gasoline Direct Injection system will allow better fuel spray and following combustion process. It is especially important in spray-guided mixture creating. The analysis mainly relates to the parameters of the fuel spray: spray penetration, observed fuel spray area in reference to both a single fuel spray and two angularly fuel sprays. The assessment of the uniformity of the fuel spray penetration for both sprays has been carried out.

The current paper is a continuation of research on fuel atomization presented in SAE 2012-01-1662. The influence of varied position of the injector inside the combustion chamber on combustion, toxic compounds formation and exhaust emission were investigated. The simulation research (injection and combustion with NO formation) was supported with the model using the FIRE 2010 software by AVL. Modelling studies of toxic compounds formation were compared with the results of measurements on single-cylinder AVL 5804 engine. There thermodynamic evaluation indicators and exhaust emission were made.

The paper presents experimental and model research related to the fuel spray - wall interaction in terms of pressure and air back-pressure variability. Using a constant volume chamber the authors performed a qualitative and quantitative analysis of the fuel spray reaching the piston. The experimental research was supported with a model research using the FIRE 2010 software by AVL. On this basis the fuel concentration and its distribution in individual areas of the combustion chamber were determined (in the piston combustion chamber). A greater impact of the injection pressure (rather than the back-pressure) on the fuel spray distribution in the combustion chamber was observed and on the fuel spray interaction with the chamber walls in the piston. In such a case the problems of the contact of a liquid fuel with the cylinder walls and/or the combustion chamber walls is becoming increasingly important in terms of the fuel film formation and HC emission intensification.

The paper presents the results of the investigations of an armored modular vehicle 8x8 Rosomak fitted with a diesel engine during start and warm-up. For the measurements of the toxic compounds a portable SEMTECH DS analyzer by SENSORS was used. The analyzer allowed a measurement of exhaust emission at the same time measuring the mass flow rate of the exhaust gases. The analysis of the PM emission was performed based on the measurement of the size of the particulate matter (analyzer 3090 EEPS - Engine Exhaust Particle Sizer™ Spectrometer - by TSI Incorporated) and counting of the particles (analyzer Particle Counter by AVL). The measurements of CO, HC, NOx, PM and fuel consumption have also been carried out under static conditions, during startup and at constant engine speed without engine load. For the measurement of the engine operating conditions and the fuel consumption a diagnostic vehicle system was used.

The paper discusses the analysis of ethanol (E85) fuel atomization generated by piezoelectric fuel injectors operating in a high-pressure gasoline direct injection system. The methodology and tests results of the influence of the fuel (E85) injection pressure and combustion chamber back pressure on the changes of the fuel spray geometrical parameters during the injection and on the values characterizing the injection quality have been presented in the paper. The tests were performed for one value of the air backpressure (1.5 MPa; as in modern supercharged DI engines) at the injection pressures of 5 and 20 MPa. The following comparative indexes were analyzed: linear and radial spray penetration during the injection and the velocity of the spray propagation. The investigation consisted in a visual recording of the process of fuel (ethanol E85) injection realized into a high pressure chamber.

In the paper the results of a comparative analysis of the changes in the fuel spray shape, penetration and its angle in the piezoelectric injection have been discussed. The results of the observation of the fuel (bio-diesel) spray with the use of high-speed camera (100 μs frame frequency) have been presented. The tests were performed for a multi hole piezoinjector and each time the whole fuel spray was observed and analyzed. The injector was placed in a closed chamber with an adjustable backpressure in the range of 0-4.5 MPa. At this stage of the research the authors investigated the influence of the chamber backpressure on the fuel spray shape, atomization and spray front displacement. Moreover, the parameterization and digital processing (including automation) of the obtained images have been presented, too. The influence of the pressure and the timing of the injection on the variable-in-time spray parameters have been shown.

The paper discusses the analysis of gasoline atomization generated by piezoelectric fuel injectors operating in a high pressure direct injection system. The methodology and tests results of the influence of the fuel injection pressure and combustion chamber back pressure on the changes of the fuel spray geometrical parameters during the injection and on the values characterizing the injection quality have been presented in the paper. It was stated that the growth in the back pressure by 50% results in a decrease in the linear spray penetration by 15% and a change in the injection pressure by 25% reduces the spray penetration by 1.6-4%. Similar relations are found for the fuel spray area and are even stronger for the spray penetration velocity.