This thesis deals with energetical and efficiency comparison of two tractor transmission types, used by the Zetor company. The description of transmission construction types of various tractor producers is given, with focus on Zetor tractors transmission construction. The laboratory methodology and operating tractor and tractor sets measurement is described. The individual results are introduced in tables and graphs and subsequently evaluated.

Táto práca sa zaoberá významom a možnosťami rekuperácie tepla výfukových plynov, ktoré pomáhajú pri štarte urýchliť zahrievanie motora a tým znižovať emisie. Teoretická časť pojednáva o emisiach a v snahe znížiť ich o predošlých konštrukčných riešeniach v priebehu rokov. Praktická časť je venovaná vytvorení modelov s implementovanými systémami rekuperácie tepelnej energie a ich dopad na teplotu chladiacej kvapaliny a oleja ako aj na celkovú spotrebu vozidla.

Emission limits and economic situation pressure automobile manufacturer, over the prospective buyer, to production more economy car. One of the elements which may indirectly reduce for example fuel consumption is automobile radiator. Construction of these accessories isn’t simple and simulation its characteristics need inspection in real measurements. Test bench for automobile radiator can help to easily choice and the project cooling system of the vehicles.

Nowadays the needs to fulfill severe emission standards and to reduce the mobile machine operative costs have driven the off-highway industrial research towards new solutions able to increase the overall vehicle efficiency. Within this scenario, smart power split transmissions demonstrated to be a very attractive technology able to achieve the fuel consumption reduction targets, increasing the machine working cycle productivity. Compared to the standard technologies (such as Torque Converters - TC), the power split hydromechanical varible transmissin (HVT), designed and developed by Dana Rexroth Transmission Systems S.r.l. (DRTS), is able to fully decouple the engine to wheel behavior during the machine working cycle, with an higher efficiency than a pure hydrostatic transmission. Due to this fundamental characteristic, the HVT allows the engine to work next to the maximum efficiency point, consequently it is possible to downsize the engine to further increase the fuel saving. The analysis of the field test performed by an off-highway vehicle (Kalmar Cargotec DRG Gloria 450 reachstacker) equipped with a DRTS HVT has been shown along this paper; particular attention has been given to the cycle load spectra, the fuel consumption and the working cycle productivity through a comparison with standard TC technologies.

America’s energy crunch— something new for a country that has been used to great affluence. America’s smog— an eye stinging, lung burning situation which the Environmental Protection Agency has "promised" to rectify. These are two outstanding problems that face the engineer and scientist of today. The end of the era of cheap gasoline has brought the beginnings of a quiet revolution to Detroit: an improvement in the efficiency, economy and emission level of the American automobile. Word has penetrated to the automotive engineers that the emissions level, fuel economy and automobile safety are the prime design considerations for the automobile of the future.

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The electric vehicles, as the most promising solution for achieving high fuel economy, have significantly better emission profile than conventional vehicles powered by fossil fuels. However, range anxiety and the limited accessible fast-charging infrastructures mainly restrain the drivers from adopting the electric vehicles that have much higher energy efficiency. Due to the internal and external factors, the cells in the battery pack degrade differently, leading to a usable capacity that is less than the available capacity if they are left unbalanced, which ultimately shortens the driving range. Therefore, an external circuitry, i.e. battery balancing circuit, that manages the unbalanced cells is installed to maximize the usable capacity, and thus, to prolong the driving range. However, the most commonly adopted balancing circuit is the dissipative balancing strategy in the large-scale electric vehicle productions, where the available capacity is underutilized. One of the most efficient redistributive balancing strategies that overcome the drawbacks of the dissipative one is converter-based strategy that monitors and regulates each paralleled-connected cell module. Nevertheless, installing the individual DC-DC converters on each module is not cost-friendly, and thus, reducing the cost of the converter-based balancing system becomes the priority for large adoptions of the redistributive balancing systems in electric vehicles. This thesis proposes a dual-cell link that integrates the functionalities of the auxiliary power module, battery gauging and battery balancing, leading to a low-cost solution comparable with the dissipative balancing. The topological improvements are made achieving 50% less number of the needed converters compared with the existing topologies. In addition, the integration and minimization are the design targets in terms of the main circuit components. The costly components, such as MOSFETs and magnetic components, are curtailed by 62.5%-75% and 50%-100%, respectively, with no sacrifices on the balancing speed. In order to achieve the magnetic integration, the detailed circuit model is developed using average- and small-signal modeling techniques. The design procedure for the half-full bridge converter with the cored transformer is firstly discussed, followed by a further minimized dual-half active bridge converter with a coreless transformer. Following the design procedure, two systems are characterized, built, tested and validated with the real batteries. Not only is the cost reduced, but also the balancing process is facilitated, which is realized by an additional balancing path. A DC current offset between the adjoining cells in one link can be introduced to the circuit by utilizing a normally undesired volt-amp imbalance in the transformer, which provides the extra cell-to-cell balancing path. An asymmetric duty cycle control is proposed to regulate the DC current offset so that the different balancing modes can be achieved. With the enabled cell-to-cell path, the balancing speed can be reduced by 50% compared with the conventional cell-to-stack only balancing methods with a state-of-charge difference of 20% between two adjoining cells. The auxiliary power module requires the proposed converters to work as efficiently as possible within its wide operating range. However, the efficiency of the half-bridge systems drops at light-load conditions due to the loss of the soft-switching capability and high conduction loss. In order to overcome this drawback, the variable frequency modulation is normally preferred. A conduction-loss based control criteria is proposed, inheriting the benefits of the conventional variable frequency modulation while maintaining the optimized conduction loss. It is validated on the converter prototype that the proposed control criteria can achieve 1-2% better efficiency with an extremely simple but robust control logic compared with the critical soft switching.

This dissertation discusses network wide signal control strategies base on connected vehicle technology. Traffic congestion on arterials has become one of the largest threats to economic competitiveness, livability, safety, and long-term environmental sustainability in the United States. In addition, arterials usually experience more blockage than freeways, specifically in terms of intersection congestion. There is no doubt that emerging technologies provide unequaled opportunities to revolutionize “retiming” and mitigate traffic congestion. Connected vehicle technology provides unparalleled safety benefits and holds promise in terms of alleviating both traffic congestion and the environmental impacts of future transportation systems. The objective of this research is to improve the mobility, safety and environmental effects at signalized arterials with connected vehicles. The proposed solution of this dissertation is to formulate traffic signal control models for signalized arterials based on connected vehicle technology. The models optimize offset, split, and cycle length to minimize total queue delay in all directions of coordinated intersections. Then, the models are implemented in a centralized system—including closed-loop systems—first, before expanding the results to distributed systems. The benefits of the models are realized at the infant stage of connected vehicle deployment when the penetration rate of connected vehicles is around 10%. Furthermore, the benefits incentivize the growth of the penetration rate for drivers. In addition, this dissertation contains a performance evaluation in traffic delay, volume throughput, fuel consumption, emission, and safety by providing a case study of coordinated signalized intersections. The case study results show the solution of this dissertation could adapt early deployment of connected vehicle technology and apply to future connected vehicle technology development.

This master thesis project aims to complete and verify core functions of a test rig that is designed and built to emulate drive cycles for measuring the energy consumption of HEVs, especially a vehicle named ELBA from KTH Integrated Transport Research Lab (ITRL). To fulfill this goal, a simplified model is created for the test rig, whose involved parameters are identified through various experiments. Then the model is verified by both step voltage responses and sinusoidal current responses. Meanwhile, vehicle dynamics is modeled to calculate required resistance force for road slope emulation. Moreover, an existing method, vehicle equivalent mass, is utilized to compensate dynamic force of the vehicle body, enabling simulation of regenerative braking without an extra flywheel. Together with test rig’s model that is responsible for converting required resistance force to demanded current reference, the rig’s functions are completed and ready for final verification. As a result, the driver of the DC motor on the rig is found to has lower current limitation than required so that the rig is not able to entirely compensate dynamic force of the car. However, the feasibility of the principle is still proved by the tests. Based on the result, recommendations are given to solve the problem and achieve other improvements in the future. / Detta examensarbete syftar till att slutföra och verifiera kärnfunktioner i en testrigg som är designad och byggd för att emulera körcykler för att mäta energiförbrukningen för elhybridbilar, särskilt ett fordon som heter ELBA från KTH Integrated Transport Research Lab (ITRL). För att uppfylla detta mål skapades en förenklad modell för testriggen, vars parametrar identifieras genom olika experiment. Sedan verifieras modellen av både stegspänningssvar och sinusformade strömsvar. Under tiden modelleras fordonsdynamiken för att beräkna erforderlig motståndskraft för väglöpemulering. Samtidigt modelleras fordonsdynamiken för att beräkna den erforderliga motståndskraften för emulering av väglutningar. Dessutom används en befintlig metod, fordonsekvivalentmassa, för att kompensera fordonskroppens dynamiska kraft, vilket möjliggör simulering av regenerativ bromsning utan extra svänghjul. Tillsammans med testriggens modell som är ansvarig för att konvertera erforderlig motståndskraft till efterfrågad strömreferens, är riggens funktioner färdig och redo för slutlig verifiering. Som ett resultat har föraren av likström motorn på riggen visat sig ha lägre strömbegränsning än vad som krävs så att riggen inte helt kan kompensera bilens dynamiska kraft. Emellertid bevisas principens genomförbarhet fortfarande av testerna. Baserat på resultatet ges rekommendationer för att lösa problemet och uppnå andra förbättringar i framtiden.

The efficiency of the transport sector is under close examination due to multiple different reasons. Among them are the environmental aspects of emission reduction along with the need to maintain a tight time schedule. Heavy trucks have a significant negative impact on the environment and are sensitive to external factors. Planning green routes is a way to minimize the emissions from heavy trucks by reducing the fuel consumption without sacrificing travel time. This thesis will investigate suspected parameters relevance to the fuel consumption of heavy trucks and their effect on the fuel consumption on heavy trucks. To achieve this, two independent literature searches were conducted, the first to find the relevance and the second to understand the effect. Then a comparison was made with the NVDB to see if the suspected parameters were represented by the attributes in the database. The result of the first literature search varied and the speed and congestion parameter showed the strongest relevance to the fuel consumption of the heavy truck. The second literature search found past research that stated that the fuel consumption of heavy trucks were affected by the parameters, gradient, speed, road curvature, road roughness, congestion, road elements and weather. The result of the investigation of attributes in the NVDB is displayed with respect to green routing. The relevance measure in the first literature search was assumed to be higher if the number of relevant articles were high. The results of the second literature search were discussed with respect to green routing. This was followed by suggesting eventual improvements in the NVDB and improvements in the method used in this thesis. Furthermore, the parameters usage and implementation in GIS were discussed. It was concluded that all parameters found in the second literature search except weather were appropriate for green routing. Other parameters could also have an effect on the fuel consumption of heavy trucks but further research is necessary to investigate this.