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Study on selected parameters of engine with the active combustion chamber

Głogowski Michał, Woźniak Marek, Szydłowski Tomasz, Siczek Krzysztof

Combustion Engines

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2023

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R. 62, nr 3

3--12

EN

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.

2

The effect of machined valve springs application on dynamic properties of electro-hydraulically driven valve train

Szydłowski Tomasz, Siczek Krzysztof, Głogowski Michał

Combustion Engines

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2022

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R. 61, nr 4

92--120

EN

Nowadays, the constant striving to reduce the emission and increase the overall efficiency over a wide range of speeds and loads of the internal combustion engine (CE) is observed. The different methods for improving the charge exchange in the engine, particularly ones based on the variable valve timing are sought. This variability can be achieved, among others by using the electrohydraulic valve drive. The goal of the present study is to compare the dynamic parameters of the engine valvetrain utilizing the unilateral electrohydraulic valve drive and various types of valve springs. The model of such a drive being developed by authors and experimentally verified was used for the analysis. Using the Finite Element Method, the models of springs made through the machining from single sleeves were developed. The effect of various geometrical parameters of the modernized springs on their stiffness and on the resulted valvetrain dynamics was examined.

3

Method of reconstructing dynamic load characteristics for durability test Indexed by: of heavy semitrailer under different road conditions

Czarnuch Arkadiusz, Stembalski Marek, Szydłowski Tomasz, Batory Damian

Eksploatacja i Niezawodność

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2021

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Vol. 23, no. 3

548--558

EN

The aim of the article is to present and validate a methodology for collecting road load data on a vehicle, driving on roads and analysis of a drive data signal under the wheel in the time domain, using FRF (Frequency Response Function) and the MTS 320 eight-poster inertia reacted road simulator. The elaborated drive data, was used to control the actuators forcing the movements of the wheels and the coupling part of the semi-trailer during durability tests. The road tests were carried out by registering physical variables in the time domain, by a set of sensors mounted on a vehicle. The data was collected from roads categorized as motorways, national and local roads. Differences between the variability of the parameters, collected on the roads and the variability of the drive data under the wheel, were determined for the particular types of roads, for loaded and unloaded vehicle. The obtained accuracy of reconstruction of the road load data conditions was as high as 97%. Therefore, the proposed method is suitable for reliable durability tests with use of the road simulator.

4

The effect of dynamics of the swash plate-slippers-piston assembly on friction torques in bearings in compressor of cooling aggregate

Woźniak Marek, Szydłowski Tomasz, Siczek Krzysztof

Mechanics and Mechanical Engineering

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2020

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Vol. 24, nr 1

42--55

EN

The swash plate type compressor utilized in car air conditioning devices and cooling system was analyzed in this study. Proper dynamic behavior of the components in such a compressor affected the correct functioning of the whole system. The aim of the study was to identify the characteristics of the main motion components in the swash plate-slippers-piston assembly of the compressor and to estimate the friction torques in its bearings. Some models of this assembly are elaborated and presented in the paper. The main components of slipper complex motion were identified, such as reciprocal motion along the axis of piston, rotation around piston axis, and short-time rotation around its own axis. Friction torque in axial bearing was higher than in journal bearing and varied with the rotational angle. Friction torques in journal bearings varied with the rotational angle and had different courses for two bearings of the compressor.