Hydraulic Transmission of Agricultural Machine Appropriate for Treating Extreme Steep Farmland Terrains

The paper presents the conception and design of the hydraulic transmission for agricultural machine appropriate for the treatment of extreme steep farmland. The small IC diesel engine powers a hydraulic pump that feeds the drive system as well as all working accessories. Hydraulic transmission systems perfectly satisfy the basic condition about the lowest weight but initially, they require totally new management. This paper outlines a simple but effective management system consisting of basic valves, electric sensors, and switches, which fits perfectly this specialized machine. The management enables the use of the potential energy for powering the accessories. When climbing up and downhill, the power is automatically distributed to the driving wheels or a winch, depending on the situation on the terrain. Significant working situations of the machine are predicted and analyzed. The appropriate function diagrams, hydraulic schemas and analytical calculations are presented. To raise the efficiency of the machine the close and the open hydraulic circuits are treated and analyzed. The machine is prototyped and partially tested. The results confirmed a big fuel saving of about 30 percent as predicted

Influence of fuel properties on engine characteristics and tribology parameters

U radu se razmatra korištenje mineralnog dizelskog goriva, čistog biodizelskog goriva, te njegovih mješavina i utjecaj svojstava goriva na značajke motora s ciljem smanjenja štetnih emisija. Za eksperimente je korišten autobusni dizelov motor, te čisto biodizelsko gorivo proizvedeno iz repičina ulja i nekoliko njegovih mješavina s mineralnim dizelskim gorivom. Gustoća, viskoznost, površinska napetost i brzina zvuka ispitivanih goriva određivane su eksperimentalno i vrijednosti su uspoređivane s istima od mineralnog dizelskog goriva. Dobivene rezultate smo upotrijebili za analizu najvažnijih značajki motora i triboloških parametara.This paper deals with the mineral diesel, neat biodiesel and their blends and it discusses the influence of fuel properties on the engine characteristics with the aim to reduce harmful emissions. The considered engine is a bus diesel engine. The considered fuels are neat biodiesel from rapeseed oil and some of its blends with mineral diesel. The density, viscosity, surface tension, and sound velocity of tested fuels are determined experimentally and compared to those of mineral diesel. The obtained results are used to analyze the most important engine characteristics and tribology parameters

Designs and optimizations of active and semi-active non-linear suspension systems for a terrain vehicle

This paper introduces a design and optimization procedure for active and semi-active non-linear suspension systems regarding terrain vehicles. The objective of this approach is the ability to quickly analyze vehicles\u27 suspension performances resulting from passive, active, or semi-active systems. The vehicle is represented by a mathematical model regarding a quarter of it, and equations for motion are derived and solved by using MATLAB/Simulink. In order to verify the reliability of the derived computer program, a comparison is made with one of the comprehensive commercial software packages. The decision parameters of the active damping device are optimized by using the Hooke-Jeeves method, which is based on non-linear programming. The usefulness of the treated active and semi-active systems on a concrete terrain vehicle is presented and compared with the presented passive systems by analyzing the vehicle\u27s body acceleration, velocity, displacement, and vertical tire force, namely those aspects that directly influence driving comfort and safety.Za terenska vozila je značilno zelo veliko premikanje koles v vertikalni smeri, saj se s tem prepreči nevarnost prevračanja, ko vozilo potuje po neravnem terenu. Zaradi te značilnosti morajo imeti terenska vozila učinkovit sistem obes, saj morajo potnikom pri vožnji zagotavljati tudi ustrezno udobje in varnost. Konstruktorji vozil posvečajo veliko pozornost tako oblikovanju obes kakor tudi njihovi optimizaciji, vse z namenom, da bi izboljšali vozne lastnosti. Osnovni namen sistema obes je zagotoviti dober kontakt koles z neravno podlago, kar je možno izvesti samo z bolj ali manj kompliciranim sistemom obes

Influence of biodiesel on injection, fuel spray, and engine characteristics

This paper discusses the influence of biodiesel on the injection, spray, and engine characteristics with the aim to reduce harmful emissions. The considered engine is a bus diesel engine with injection M system. The injection, fuel spray, and engine characteristics, obtained with biodiesel, are compared to those obtained with mineral diesel under peak torque and rated conditions. The considered fuel is neat biodiesel from rapeseed oil. Its density, viscosity, surface tension, and sound velocity are determined experimentally and compared to those of mineral diesel. The experimentally obtained results are used to analyze the most important injection, fuel spray, and engine characteristics. Furthermore, the influence of biodiesel usage on lubrication is presented briefly. The results indicate that, by using biodiesel, harmful emissions (NOx, CO, HC, smoke, and PM) can be reduced to some extent by adjusting the injection pump timing properly while keeping other engine characteristics within acceptable limits. Furthermore, the results indicate better lubrication conditions when biodiesel is used

Influence of biodiesel on injection, fuel spray, and engine characteristics

This paper discusses the influence of biodiesel on the injection, spray, and engine characteristics with the aim to reduce harmful emissions. The considered engine is a bus diesel engine with injection M system. The injection, fuel spray, and engine characteristics, obtained with biodiesel, are compared to those obtained with mineral diesel under peak torque and ratedconditions. The considered fuel is neat biodiesel from rapeseed oil. Its density, viscosity, surface tension, and sound velocity are determined experimentally and compared to those of mineral diesel. The experimentally obtained results are used to analyze the most important injection, fuel spray, and engine characteristics. Furthermore, the influence of biodiesel usage on lubrication is presented briefly. The results indicate that, by using biodiesel, harmful emissions (NOx, CO, HC, smoke, and PM) can be reduced to some extent by adjusting the injection pump timing properly while keeping other engine characteristics within acceptable limits. Furthermore, the results indicate better lubrication conditions when biodiesel is used

Improvement of engine performance using an optimization procedure

This paper presents a simple and effective approach to improve engine performance of a racing car with special requirements. Attention is focused onoptimal design of the intake system, using a gradient-based approximation method of mathematical programming. Since optimization relies on accurate numerical analysis of engine processes, the sub-models and parameters needed in the analysis software are carefully determined by experiment. Subsequently,the influence of different design parameters of intake and exhaust systems on engine performance is investigated numerically. The most influencing parameters are selected to be the design variables in the optimization process. In order to improve engine power at several engine speeds, two different forms of the optimal design problem are proposed, solved, and compared as a means to identify the most appropriate one. Since the analysis software is a black-box program, the optimization procedure is implemented by employing the optimization software as a master (driver) program while the analysis software acts as the slave program. The data exchange between these programs is established by XML data files and suitable wrapper programs. The results obtained confirm the usefulness of the approach presented

Developing a racing car

V prispevku sta prikazani dve moznosti izboljšanja lastnosti dirkalnika Formula S. Eden najskladnejsih načinov za dvig moči motorja je spretno oblikovan dovod zraka v motor. Zato je v prvem delu prispevka predstavljen postopek optimalnega oblikovanja sesalnega sistema. Postopek optimiranja temelji na uporabi metod matematičnega programiranja in pomeni učinkovit način za povečanje moči motorja v najbolj zanimivem področju obratovanja motorja. V drugem delu prispevka je pozornost posvečena novim zamislim izdelave celotnega dirkalnika. Za dosego vrhunskih rezultatov je treba narediti več, kakor le slediti konkurenci. Analiza postavitev glavnih agregatov je pokazala, da bi k večji okretnosti in stabilnosti dirkalnika pripomoglo to, da bi bil motor postavljen ob voznikovi strani. Optimiran sesalni sistem pomeni zanesljiv korak naprej v borbi za povečanje dejanske moči dirkalnika, kar je lahko uporabno takoj. Zasnova z bočno postavitvijo motorja pa predstavlja povsem novo pot razvoja dirkalnikov Formula S, kar bo morda prineslo dolgoročne prednosti.This article presents two approaches for improving a Formula S racing car. Oneof the best ways to increase the enginećs power is to skillfully design theair- supply system of the engine. This is the reason why the first part of the paper is about the intake-manifold optimization procedure. The procedure relies on mathematical programming and offers a way to significantly increase the engine power in the most important engine regimes. In the second part of the paper, attention is focused on new concepts of building the racing car. Inorder to be the best it is necessary to do more than symply follow the competion. An analysis of the positions of the main components has shown that a racing car would be more agile and stable if the engine was to be mounted beside the driver. Optimizing the intake manifold represents one significant step forward in the struggle to increase the effective power of the car, whichbrings an immediate advantage. The new position concept, however, which also eliminates the differential drive, represents a completely new development in the design of the Formula S car that might bring us long-term benefits