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 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

What affects the e‐bicycle speed perception in the era of eco‐sustainable mobility: A driving simulator study

The increase in the number of electric bicycles worldwide has resulted in a rise in the number of traffic accidents involving e‐bicyclists. Previous studies have been based on analyzing the use, advantages and disadvantages of e‐bicycles, whereas only a small number of studies have been focused on analyzing the e‐bicycle traffic safety, particularly the factors leading to the occurrence of traffic accidents. One of the factors affecting the occurrence of traffic accidents is the incorrect perception of the e‐bicycle speed by other traffic participants. To examine the mentioned problem, the authors of this paper conducted an experimental study to determine what affects the e‐bicycle speed perception. The experiment included 175 participants, aged 18 to 50. The research was conducted under laboratory conditions using a driving simulator, at different e‐bicycle speeds (10 km/h, 20 km/h and 30 km/h), in the situations in which the e‐bicyclist was (not) using a reflective vest. The results show statistically significant differences in the e‐bicycle speed perception when the e‐bicyclist does not use/uses a reflective vest. Besides, the driving licence categories of traffic participants and their driving experience also have a significant impact on the perception of the e‐ bicycle speed

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