Experimental verification of mathematical model of the heat transfer in exhaust system

A catalyst convertor has maximal efficiency when it reaches working tempera-ture. In a cold start phase efficiency of the catalyst is low and exhaust emissions have high level of air pollutants. The exhaust system optimization, in order to de-crease time of achievement of the catalyst working temperature, caused reduction of the total vehicle emission. Implementation of mathematical models in devel-opment of exhaust systems decrease total costs and reduce time. Mathematical model has to be experimentally verified and calibrated, in order to be useful in the optimization process. Measurement installations have been developed and used for verification of the mathematical model of unsteady heat transfer in ex-haust systems. Comparisons between experimental results and the mathematical model are presented in this paper. Based on obtained results, it can be concluded that there is a good agreement between the model and the experimental results

Aspects of volumetric efficiency measurement for reciprocating engines

The volumetric efficiency significantly influences engine output. Both design and dimensions of an intake and exhaust system have large impact on volumetric efficiency. Experimental equipment for measuring of airflow through the engine, which is placed in the intake system, may affect the results of measurements and distort the real picture of the impact of individual structural factors. This paper deals with the problems of experimental determination of intake airflow using orifice plates and the influence of orifice plate diameter on the results of the measurements. The problems of airflow measurements through a multi-process Otto/Diesel engine were analyzed. An original method for determining volumetric efficiency was developed based on in-cylinder pressure measurement during motored operation, and appropriate calibration of the experimental procedure was performed. Good correlation between the results of application of the original method for determination of volumetric efficiency and the results of theoretical model used in research of influence of the intake pipe length on volumetric efficiency was determined

Numerical Analysis of IC Engine Operation with High-Pressure Hydrogen Injection

The limited quantities of oil reserves and the exhaust emissions from IC engines have become a threat to the existence of IC engines. One of the best solutions to the problem is the use of alternative fuels. Hydrogen is an alternative fuel that is called a fuel of the future. A disadvantage of hydrogen is its high combustion speed. Experimental results were used for the determination of inputs for numerical analysis. The numerical analysis is performed for a 3D model of the engine in order to determine the working parameters of the engine (pressure and temperature). The main goal of this study is to investigate a possibility of modifying the diesel engine so that it can run on hydrogen. It was found that in such an engine the greatest loads occur in the combustion chamber; thus, the vital parts of the engine are protected. Therefore, a mechanical analysis of the combustion chamber was performed (calculation of stresses and deformations). The obtained results are encouraging because they indicate that by applying the presented solution a much cheaper technology than the modern diesel engine systems is made possible

Experimental determination of double vibe function parameters in diesel engines with biodiesel

A zero-dimensional, one zone model of engine cycle for steady-state regimes of engines and a simplified procedure for indicator diagrams analysis have been developed at the Laboratory for internal combustion engines, fuels and lubricants of the Faculty of Mechanical Engineering in Kragujevac. In addition to experimental research, thermodynamic modeling of working process of diesel engine with direct injection has been presented in this paper. The simplified procedure for indicator diagrams analysis has been applied, also. The basic problem, a selection of shape parameters of double Vibe function used for modeling the engine operation process, has been solved. The influence of biodiesel fuel and engine working regimes on the start of combustion, combustion duration and shape parameter of double Vibe was determined by a leastsquare fit of experimental heat release curve

Measurements and modeling pollution from traffic in a street canyon: Assessing and ranking the influences

More than half a century, the scientific community is trying to understand the mechanisms and conditions of pollution dispersion within urban areas. Thereat, special attention has been focused on specific areas, such as a street canyon, in which harmful concentrations higher than allowed are more likely registered. However, there is still a controversy about the conditions of occurrence and impact of the individual air pollution components due to fluctuations of key contributions. Given that OSPM is a well-known semi-empirical model specializing in the assessment of air quality within a street canyon. After its testing and validation, the results of subsequent simulations were used as a basis for planning a special experiment in order to implement 48 full factorial designs. Using the response surface methodology, as the final objective, an answer was precisely given on the impact and contribution of urban air pollution components. In addition to the main objective of this study, as a secondary, but not less important result defining emission factors for CO and NOx can be emphasized, which to date have not been determined for the fleet of Serbia

A diesel engine performance measurement with diesel fuel and biodiesel

© 2019 Society of Thermal Engineers of Serbia. Rapid growth in the energy consumption has conditioned the need for discovering the alternative energy resources which would be adapted to the existing engine constructions and which would satisfy the additional criteria related to the renewability, ecology, and reliability of use. The experimental research are conducted according to the (European Stationary Cycle-Directive 1999/96/EC) 13-mode. Using biodiesel fuel average thermal efficiency is kept at the level of the application of conventional diesel fuel, average emission of CO is reduced by 13.6%, average emission of NO is increased by x 27.6%, average emission of hydrocarbon is increased by 59.4%, and average particles emission is reduced by 43.2%

Aspects of volumetric efficiency measurement for reciprocating engines

The volumetric efficiency significantly influences engine output. Both design and dimensions of an intake and exhaust system have large impact on volumetric efficiency. Experimental equipment for measuring of airflow through the engine, which is placed in the intake system, may affect the results of measurements and distort the real picture of the impact of individual structural factors. This paper deals with the problems of experimental determination of intake airflow using orifice plates and the influence of orifice plate diameter on the results of the measurements. The problems of airflow measurements through a multi-process Otto/Diesel engine were analyzed. An original method for determining volumetric efficiency was developed based on in-cylinder pressure measurement during motored operation, and appropriate calibration of the experimental procedure was performed. Good correlation between the results of application of the original method for determination of volumetric efficiency and the results of theoretical model used in research of influence of the intake pipe length on volumetric efficiency was determined

Experimental determination of double vibe function parameters in diesel engines with biodiesel

A zero-dimensional, one zone model of engine cycle for steady-state regimes of engines and a simplified procedure for indicator diagrams analysis have been developed at the Laboratory for internal combustion engines, fuels and lubricants of the Faculty of Mechanical Engineering in Kragujevac. In addition to experimental research, thermodynamic modeling of working process of diesel engine with direct injection has been presented in this paper. The simplified procedure for indicator diagrams analysis has been applied, also. The basic problem, a selection of shape parameters of double Vibe function used for modeling the engine operation process, has been solved. The influence of biodiesel fuel and engine working regimes on the start of combustion, combustion duration and shape parameter of double Vibe was determined by a least square fit of experimental heat release curve

Valve dynamics in reciprocating compressors for motor vehicles

© 2017, Strojarski Facultet. All rights reserved. Reliability and thermodynamic properties of reciprocating compressors are largely dependent on the valve. Since the valves open and close automatically, there is an intensive impact of the valve and the sealing element dynamics to the gas flow through the valve. Poor valve characteristics inevitably lead to degradation of compressor performance and/or short lifetime of the valve. A short lifetime of the valve is the result of excessive impact forces between the sealing element and other parts of the valve assembly. Matching the valves to the specific reciprocating compressor is a complex task that requires the use of appropriate mathematical models before the realization of the valve. The mathematical model for the prediction of the valve dynamics is presented within this paper. The mathematical model is verified by measurements of thermodynamic characteristics of the specific reciprocating compressor used in motor vehicles. It is concluded that the mathematical model agrees well with the results of laboratory tests