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Not only electrical hybrid technology is used for drivetrain of passenger cars. Also other systems using non-electrical principles (hydraulic or air pressure, mechanical energy storage) can be found in modern vehicles. There is a quantification of the spared energy by using a hybrid vehicle in the paper. Driving cycle ECE 15 was chosen as a platform for simulation of driving resistances.

Electric or hybrid vehicles are becoming increasingly common on roads. While electric vehicles are still more or less intended for city traffic, hybrid vehicles allow normal use due to wider driving range. The use of internal combustion engines in hybrid drives is still an inspiration to find the way to reduce the production of emissions. Numbers of alternative energy resources were studied as a substitution of conventional fuels for hybrid vehicles drives worldwide. The paper deals with the possibility of using alternative fuels as CNG, LPG and LNG in combination with hybrid drive of a midibus with the capacity of 20 passengers. Various aspects and techniques of hybrid vehicles from energy management system, propulsion system and using of various alternative fuels are explored in this paper. Other related fields of hybrid vehicles such as changes of vehicle weight or influence of electric energy sources on the total vehicle emission production are also included.

This paper addresses the issue of metrological accuracy of instantaneous in-cylinder pressure measurement in a diesel engine test bed. In studies, the central unit has been the single-cylinder AVL 5402 engine. The pressure measurement was performed with a sensor designed for thermodynamic analysis, and the results were related to the crank angle, where two rotations corresponding to the four-stroke working cycle were denoted as angles between −360° and +360°. The novelty of this paper is the proposition of how to perform a type A uncertainty estimation of the in-cylinder pressure measurement and to assess its repeatability. It was demonstrated that repeatability of the measurement during the ignition process was difficult to estimate because of the phenomena that cannot ensure the repeatability conditions. To solve the problem, two methods were proposed. In one method, the pressure was measured in the subsequent cycles immediately after the ignition was turned off, and in another method, the engine was driven by a starter. The latter method provided maximal pressure values much lower than during usual tests. The obtained repeatability of measured pressure was %EV = 0.4%, which proved high capability of the evaluated measurement system.

The aim of this study was to analyse the possibilities of improving the ecological parameters of compression-ignition CI engines. During the analysis of exhaust gas, attention was mainly paid to the emission of nitrogen oxides and carbon black soot. A method was proposed to reduce the above chemical elements in CI-engine exhaust fumes by using the annular channels on the non-working part of the fuel injector needle and applying a platinum catalyst on them. The task of these annular channels is to mix and agitate the fuel before injection to the combustion chamber and to enlarge the contact surface area of catalyst. The task of catalytic coating is to initiate the reaction of dehydrogenation of paraffinic hydrocarbons to olefinic ones with a free hydrogen molecule. Hydrogen, owing to its properties, can shorten the period of delay of spontaneous ignition of combustible mixture in the engine combustion chamber, which affects the entire combustion process and improves the ecological parameters of a CI engine.

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The global policy solution seeks to reduce the usage of fossil fuels and greenhouse gas (GHG) emissions, and biogas (BG) represents a solutions to these problems. The use of biogas could help cope with increased amounts of waste and reduce usage of fossil fuels. Biogas could be used in compressed natural gas (CNG) engines, but the engine electronic control unit (ECU) needs to be modified. In this research, a spark ignition (SI) engine was tested for mixtures of biogas and hydrogen (volumetric hydrogen concentration of 0, 14, 24, 33, and 43%). In all experiments, two cases of spark timing (ST) were used: the first for an optimal mixture and the second for CNG. The results show that hydrogen increases combustion quality and reduces incomplete combustion products. Because of BG’s lower burning speed, the advanced ST increased brake thermal efficiency (BTE) by 4.3% when the engine was running on biogas. Adding 14 vol% of hydrogen (H2) increases the burning speed of the mixture and enhances BTE by 2.6% at spark timing optimal for CNG (CNG ST) and 0.6% at the optimal mixture ST (mixture ST). Analyses of the rate of heat release (ROHR), temperature, and pressure increase in the cylinder were carried out using utility BURN in AVL BOOST software.

Summary. The paper presents a proposal of methodology for revitalisation of regional railway tracks and regional railway traffic, liberalization and competition in railway transport, quality requirements in regional traffic, principles of the contract on transport services in the public interest and with the current state of regional passenger transport in Slovakia and Serbia. First part of the paper deals with a theoretical approach of transport policy, transport regulation, suburban transport and introduces a methodology for revitalisation of regional railway tracks. VORSCHLAG UND ANWENDUNG DER METHODE REVITALISIERUNG