Applied Mechanics and Materials Vol. 822

Abstract: The objective of this paper is to solve the differential equation that determines the duration of the injection and the time constant (T). Moreover, the injection rate, the instantaneous and flow section through the injector are calculated depending on the needle’s lift.

Abstract: Internal combustion engines are typically equipped with an exhaust muffler to suppress the acoustic pulse generated by the combustion process. The paper presents the procedure and the experimental setup for some functional parameters determination as the noise level, the pressure drop and the temperatures through investigating three different manufacturing solutions for mufflers. An algorithm and a dedicated method have been proposed in order to emphasize more direct the mufflers influence on the engines performances. The procedure equally includes particular cycles of the engine and it is highlighted the relation between the engine operating conditions and the functional parameters of the automotive mufflers.

Abstract: This paper presents a study regarding the emissions caused by the running of a cold engine and studies the influence of the four-stroke gasoline engine’s temperature on CO₂, CO, HC emissions. Experimental research has been done for three light vehicles equipped with a 1390 cm³ Renault spark ignition engines. Several test have been made under different temperature conditions by using a BEA Emission Analyser - Bosch. The experimental data have shown that the engine’s temperature has an influence on CO₂, CO, HC emissions. The results show that the highest pollutants values are recorded for low exhaust gases temperature and for cold engine’s running regime.

Abstract: The paper presents the results obtained by investigating some functional parameters as the noise level, the pressure – drop and the temperatures of three different manufacturing solutions for mufflers. The results emphasize the corroboration between these parameters and contribute to the improvement of the muffler fabrication and design since it is a complex function that affects noise characteristics, emission and fuel efficiency of engine. It was designed a measurement chain for the noise level evaluation of the mufflers including a microphone Bruel&Kjaer type 4133, a Impulse Precision Sound Level Meter Bruel&Kjaer, type 2209, with standard filters and a multifunctional external data acquisition board type-NI DAQPad-6015 . We assessed the noise level, using two based LabVIEW virtual instruments, measuring total band power and the equivalent continuous sound pressure level. It was also created a measurement chain for the pressure – drop evaluation and temperature distribution on the external surface of the mufflers.

Abstract: Primarily, Romania relies on fossil fuels for its energy needs in transport sector. Increase in prices of conventional fuels, climate change and energy security are the reasons to find alternate solutions. China, Japan, Belgium, Brazil, Tanzania, Mexico, Thailand, Malaysia, Philippines and South Africa are already using jatropha biodiesel blends with fossil fuels. Keeping in view food security, Romania has sufficient land to cultivate jatropha. In this paper we tried to find out opportunities to cultivate jatropha in Romania and its economic comparison with fossil fuel usage. On the basis of this study, recommendations will be made for the usage of jatropha biodiesel as future road transport fuel in Romania.

Abstract: This paper presents the undertaken research for the establishment of the compatibility of some polyolefin waste to be recycled by pyrolysis. Polyolefin are materials produced by a polymerization process of unsaturated aliphatic hydrocarbons and represents the most important group of plastic materials. It is important to mention that among polyolefin, polyethylene (PE) and polypropylene (PP) own the first places as quantity of produced waste. Due to the common origin of the two plastic materials (PE and PP) and the relatively close melting points, we chose them for the obtaining of some fuels which are compatible with compression ignition engines. Starting from 100 % PE, the weight concentration of PP was increased up to 100%, the results of the undertaken experiments and measurements allowed us, in the final, to draw the chart of the variation of the yield of solid-liquid conversion as a function of weight concentration of the two chosen materials subjected to the process of recycling by pyrolysis.

Abstract: Small diesel engines with direct injection air cooled a big problem is heat dissipation. Based on bench made ​​with a 295 cc diesel engine with direct injection, air cooled, I set the heat flows through the cylinder head, piston and cylinder. These data are needed to study the possibility of operating at maximum power, knowing that mechanical stresses of thermal origin are the most dangerous. The data obtained in this work will be used in the analysis of temperature and stress fields.

Abstract: The paper presents a control algorithm for an internal combustion engine for a conventional vehicle in order to improve the comfort and driveability. Quick engine torque variations and direct interaction with the road produce driveline resonance frequency and oscillations, especially when the vehicle is used at full load. The processes from the combustion chamber engage different elements, involved in chemical reaction between air and fuel. The Matlab/Simulink software allows to optimize a few parameters involved in engine performances evolution. The injection time, the moment of injection, the load and the speed of the engine and whole electronic engine management guarantee a smooth regime of the engine and of the vehicle and reduce the noise and the pollutants and avoid supplementary stresses and dangereous oscillations of the drivetrain components of a vehicle.

Abstract: This paper describes the researches made by the authors in order to find the causes were a railcar engine damages. Investigations were made in Brasov and also in Czech Republic, onto engine manufacturer. Important conclusions and results were uses for establish what actions are necessary for such a failure will not reoccur in the future.

Abstract: This paper presents a comparative study about the performance of a classic, hybrid and electric bus by computer simulation using AVL Cruise software. The simulation tasks include main energetic, functional and dynamic parameters, over the usual city bus drive cycle. Based on the simulation results, a comparative analysis was performed for the three models of buses used for urban passenger transport. Hybrid and electric vehicles have been developed with the aim of saving energy, reducing local pollutant emissions and can be considered to offer the best short term to mid-term promise. The impact on the fuel economy generally improves by more than 50 % in urban passenger’s traffic using hybrid buses.