Piotr Krawiec

Piotr Krawiec
Poznan University of Technology · Institute of Machine Construction

About

54
Publications
20,651
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491
Citations
Citations since 2016
45 Research Items
489 Citations
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2016201720182019202020212022050100150
2016201720182019202020212022050100150
2016201720182019202020212022050100150

Publications

Publications (54)
Article
Full-text available
The continuous increase in the use of the transmissions with V-belt, the introduction of new materials for the production of belts and the development of new manufacturing techniques have become the reason for undertaking research works on the possibilities of increasing the load capacity and durability of belts as well as reducing their influence...
Article
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Mobile overpressure fans are popular tools used in rescue and extinguishing operations carried out by Fire Protection Units. They are used for exhaust and venting buildings from harmful products of thermal decomposition occurs due to fire. Health and human life may depend on the proper operations of this type of equipment. The aim of the article is...
Article
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Mechanical gears with flat belts are currently the most intensively developing group of mechanical transmissions. This is due to the need to increase the speed of moving elements of machines and to transfer torque over considerable distances. This intensive development has enabled the development of materials engineering and the emergence of modern...
Article
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Wood choppers shredding branches equipped with low power drive units (up to 10 kW) are characterized by low technical sophistication. Their work translates into the consumption of non-renewable energy sources and the emission of toxic exhaust compounds into the environment. There are innovative technical solutions that allow you to increase the eff...
Article
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The aim of the research was to show that changes occur in floor surface parameters resulting from increased use in public utility buildings. The study included corridors and staircases that differ in terms of covering material in a public utility building in Poznań. Measurements were carried out with the use of the British Pendulum Test Value (PTV)...
Article
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Aim: The aim of the article is to indicate the essential technical and operational parameters of mobile fans and to present the proposed testing method- ologies (as well as dedicated infrastructure) allowing to confirm the indicated features. Project and methods: In many places around the world, scientists conduct tests related to the use of mechan...
Article
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Machines and devices for the production, transport and segregation of products are placed in production and storage rooms. Flat conveyor and drive belts are very often used for their construction. Due to heavy loads and difficult operating conditions, these belts can catch fire and, as a result, become the main source of air contaminants harmful to...
Article
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The paper presents the procedure of generating geometrical features on the contours of non-circular pulleys through the selection of materials and technological parameters for easy and efficient production of these parts. Based on the models designed in the computer aided design (CAD) system, several prototype non-standard pulleys were made, which...
Article
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Beach cleaning and algae collection in the shoreline area are important for the tourism industry, mainly for aesthetic reasons, but also to protect human health. In addition, the collected material can be used in many industries such as energy, medicine, cosmetics or catering. The problem of cleaning the shoreline area concerns the need to clear la...
Article
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Early detection of the causes of malfunction of toothed gears, cable gears, and various types of drives enables the prevention of breakdowns and related downtime. The work concerns the possibility of using terminography in order to assess the thermal state of the V-belt of the tension transmission used in the drive of a wood chipper. This device is...
Article
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The article presents the potential impact of flat drive and transport belts on people’s safety during a fire. The analysis distinguished belts made of classically used fabric–rubber composite materials reinforced with cord and currently used multilayer polymer composites. Moreover, the products’ multilayers during the thermal decomposition and comb...
Article
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Alternative fuel within the meaning of Directive 2014/94/EU is, among others, LPG (liquefied petroleum gas), characterized by a lower purchase cost and lower emissions of toxic exhaust compounds in comparison to the combustion of classic gasoline. In wood chippers, intended for chopping branches, with low-power internal combustion engines that meet...
Article
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Aim: The aim of the article is to identify innovative design solutions in chainsaws which are used in rescue and firefighting operations. The review concerns commercial solutions, scientific publications and patents. It enables to determine development trends of chainsaws utilised as mechanical rescue devices. Project and methods: Although chainsa...
Article
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Branch chipping machines with low-power engines are distinguished with an intermittent operation due to a periodical supply of branches. A conventional drive speed control of these machines is not adapted to adjust the operating mode depending on frequency of material supply for shredding. This article discusses the issues related to the assessment...
Article
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Both energy consumption and the ecology of mobile wood-chipping machines are important issues in forest management. One way of improving the efficiency of wood-chippers is to use innovative design solutions in drive unit control systems. This can result in a reduction in fuel consumption and quantitative exhaust gas emissions. This article presente...
Article
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The development of belt transmissions with wedge belts and new materials used to produce belts inspire designers and people who deal with the exploitation of belt drives to carry research on the possibilities of increasing the load and durability of the belts. It is necessary to know the actual mechanical and rheological characteristics of the belt...
Article
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Waste management in a selective manner requires the collection of waste, among others, also large-scale. In Poland, in January and February, the collection of biodegradable waste is carried out – Christmas trees. This process is carried out by collecting from the real estate the whole trees, and then transporting them to the utilization place, wher...
Article
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This article proposes thermography as a non-contact diagnostic tool for assessing drive reliability. The application of this technique during the operation of the belt transmission with a heat-welded thermoplastic polyurethane V-belt was presented. The V-belt temperature changes depending on the braking torque load at different values of the rotati...
Article
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The effectiveness of agrocultural processes in wooded areas depends, inter alia, on the kind of machines used. Mobile machines chopping branches with low power engines are characterized by limited adaptation of the drive unit to the operating conditions. This results in increased fuel consumption and increased exhaust emissions. In order to develop...
Article
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Multiple grooved pulley wear can be evaluated by using two methods, coordinate method and optical method. This paper presents the results of the research and the analysis of the geometrical features for this type of pulleys, which was obtained with the ATOS II optical system. In this method the evaluation of wear is made based on the comparison of...
Article
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Modern drive units designed for driving non-road machines are characterized by liberal regulations regarding the limits of toxic compounds emission in exhaust gases. These regulations contribute to the low level of technical advancement of this type of drive units. Among the new non-road small engines (SI) offered in the sale in 2018 in the Europea...
Article
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Exceeding air pollution emission standards in large cities leads to a search of methods of reducing emissions and their neutralization. One of the ways to improve air quality is to increase green infrastructure in urban areas. It leads to an increase in the demand for work machines that process waste from tree care is. Mobile chopping shredders for...
Chapter
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Non-road mobile machinery driven by small spark ignited (SI) engines are one of anthropogenic sources of air pollution [18]. In combustion engines the highest influence on the generated emission of harmful exhaust fumes the kind of fuel used, construction and the way ignition-injection system is controlled as well as the system of exhaust emission...
Article
The paper presents measurement processes for noncircular cog belt pulleys using classical and Rapid Inspection methods. The authors researched various manufacturing methods in order to find an accurate, simple and cheap method of manufacturing noncircular cog belt pulleys. A characteristic feature of noncircular cog belt pulleys is the pitch variat...
Article
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Propulsion of non-road mobile machinery dedicated for the waste wood chipping these are mainly internal combustion engines. Their construction mainly affects the efficiency of wood chipping processes. Liberal homologation regulations for combustion engines used by non-road mobile machinery lead not only to relatively high emissions of harmful exhau...
Article
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The high awareness of intensification and frequency of smog phenomenon all over the world in XXI age makes for detailed analyses of the reasons of its formation and prevention. The governments of the developed countries and conscious of real hazards, including many European countries, aim to restrict the emission of harmful gases. In literature, we...
Article
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The widespread application of both gear wheels and cogbelt pulleys with noncircular generating line in technique stimulates the development of manufacturing and measuring methods of these wheels. The paper presents the rapid prototyping methods of models of cogbelt pulleys with nocircular evelope. Evaluation method of manufacturing accuracy of cogb...
Article
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This paper presents the problem of phenomena occurring at the contact of a timing belt and a pulley. Depending on a belt size range these phenomena differ significantly. There is no indication as to what solutions are optimal for drive belts. The analysis of the coupling process and performance tests have shown that the drive belt should have a cor...
Article
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The paper presents the analysis of reasons, form and wear of elements of V-belt transmission. Syndromes of loss of driving properties for chosen wheels and V-belts are specified. Methodology of failure evaluation of wheels and V-belts with the application of optical microscope is proposed. The applied measuring set allows for universal analysis of...
Article
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Carrying out a realistic research on working units of machines that grinder waste coming from tree and bush trimming requires designing machines that would be more efficient. It is neccesary both to introduce the analysis of already existing solutions as well as searching for innovative ones that would result in the increase of efficiency, lowering...
Article
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The vehicles moving on Polish roads are very often more than 10 years old and usually do not meet current eco-regulations. They are allowed into service, but the increasing pollution in urban areas leads to entry prohibition for these vehicles into the city center. The correct modernization of the vehicle can improve a reduction of emissions of har...
Article
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This paper shows the results of research which consider the influence of vacuum signal disturbance on the steering process of combustion engine. It also presents design guidelines for installations of vacuum signal between suction manifold and vacuum sensor. Diagnostic analysis was made with the use of three-dimensional fuel charge map. Additionall...
Article
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The aim of the work is the examination of dynamic characteristics of a stepper motor. The results of the investigations will be applied to assess the usability of the stepper motor as a generator of the periodically variable motion of actuators. The examples of mechanical generators of periodically variable motion are gear, chain and cogbelt transm...
Article
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Ecological, economic and exploitation requirements force manufacturers to develop propulsion systems. In the combustion engines with spark ignition for use in non-road mobile machines, it is common to use fuel supplied systems with carburetors. The mechanical adjustment process of the fuel-air mixture makes it difficult to automate the processes us...
Chapter
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Constantly exceeded permissible limits of air pollutants in urban areas around the world lead to emission reductions in all branches of industry. One of the more restrictive regulations is the one concerning emissions generated by modern passenger vehicles. Constructional solutions used there could be a guideline for the construction of drives for...
Chapter
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This article presents different modes of a sports vehicle allowed to be used on public roads on a dry asphalt surface during intensive acceleration with the use of two launch control systems. The vehicle was thoroughly characterized with paying extra attention to power train and braking system. The result of carried out experimental research and an...
Article
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The paper presents results of analysis of selected dynamic features of an uneven-running two- -wheeled strand transmission. The characteristic features of such type of transmissions is the ability of obtaining variable kinematic and dynamic features by the application of wheels with a noncircular envelope. Particularly, high interest of application...
Article
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Contemporary motor vehicles are equipped with efficient and eco-friendly engines. It is possible to control electronically such parameters as the ignition advance angle, whose computational model takes into account multiple variables. These characteristics are often determined by empirical studies and then programmed in the controller. Due to the a...
Article
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The steering system for working machines attachment is a mediator between operator and the environment, thus it is one of the main factors which influence the efficiency and safety of the operator's work. The subject of this article is the test stand which enables one to test various steering systems for the hydraulic driven working attachment. The...
Article
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The achievements of today's automotive industry and in particular its prevalence allows the existing constructions, which are characterized by a worse parameters, to meet the requirements of the 21st century. One method of improving the properties of the internal combustion engine is the modernization of the fuel and ignition system. This entails a...
Article
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Dynamiczny rozwój silników spalinowych ukierunkowany jest m.in. na proekologiczność, wzrost wydajności i obniżenie masy silnika. Wymusza to potrzebę modyfikacji zarówno silników jak i zmian w stosowanych podzespołach. Zmiany parame-trów i charakterystyk pracy oraz wymagania konstrukcyjne prowadzą do wprowadzania zmian w układach rozrządu. W arty-ku...
Article
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During design of the envelope of a noncircular belt pulley one should take into account several conditions resulting from kinematics and geometry of the uneven-running strand transmission. Design of proper values of pitches for a belt pulley, which enable good cooperation between the belt pulley and the belt, should be carefully done. In available...
Article
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The aim of the research is to analyze the influence of temperature on the characteristics of stepper motor. The research re-sults will be used to assess the suitability of the stepper motor, as generator of motion periodically-variable. The example of the application of generators of motion periodically-variable are mills, crushers, crushing or tra...
Article
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Car tire is made of a composite material, whose individual components have significantly different mechanical properties. Its primary task is to transfer forces generated by the vehicles drive system so that the driver maintains sufficient control over the vehicle, as well as to preserve optimal performance characteristics. Presence of snow and slu...
Article
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The article presents the results of experimental studies of the process of intense acceleration, passing through the barrier and the vehicle brakes adapted for the transport of persons using two speed ranges passing through the barrier. Tests were conducted on dry roads made of cobblestones. Performed experimental studies, which aim was to determin...
Article
In this paper, the possibilities for forming non-circular pulleys using laser cutting techniques and cutting techniques using water jets with abrasive materials are described. Research on laser cutting with use of gases for formation of carbon steel and acid-resistant steel pulleys is also discussed. The advantages of water jet cutting of non-circu...
Article
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This work concerns problems connected with race car's behavior permitted to traffic motion on dry asphalt surface during braking and rapid acceleration. The characteristics of the vehicle is presented with particular reference to type of tires. Environmental characteristics and road surface were made. The result of the research and analysis are kin...
Article
The aim of this paper is the analysis of the generation capabilities of noncircular cogbelt pulleys on the example of a cogbelt pulley with an elliptical pitch line. The need of elaboration of different manufacturing methods for noncircular cogbelt pulleys than existing ones for noncircular gears is shown. Relationships for the mutual position of t...
Article
The usage of noncircular gears makes possible to get better characteri-stics of the transmission. This problem is widely studied in the case of regular noncircularity, e.g., when a gear is of an elliptical or cycloidal shape. In this study, there are taken into account non-typical irregular gears. The design of such gears involves more advanced tec...
Article
In industrial practice it is often necessary to obtain information regarding the geometrical characteristics of machine elements whose documentation does not exist or is unavailable. One way to obtain such information is by applying reverse engineering methods. This paper presents the process of digitization on a numerically controlled coordinate...
Article
Selected designing and manufacturing problems of nontypical machine elements such as non-circular gears are presented in the paper. Such gears are used in uneven-running cog-belt transmissions, which allow to obtain periodically variable kinematical features. There are presented advantages and limitations of teeth forming. There was pointed a lack...

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