The article presents issues related to the assessment of concentrations of harmful substances in the exhaust gas cloud behind the vehicle. In the theoretical part, considerations about the harmfulness of exhaust gases and methods of detection of chemical compounds were made, and the issues of von Karman vortices and the Lambert-Beer law were referred to. The test object was a vehicle equipped with an SI engine meeting the Euro 3 standard. The drive unit had a capacity of 2.8 dm³, a rated power reaching 142 kW at 5500 rpm and a maximum torque of 280 Nm at 3500 rpm. The measurements of the dilution of the exhaust gas cloud behind the vehicle were made in stationary conditions (laboratory) and during actual operation in the Poznań agglomeration. In the research, technically advanced equipment from the PEMS group was used. In the analysis of the obtained results, detailed considerations were made regarding the influence of the location of the measuring probe in relation to the exhaust system. As can be seen from the obtained dependencies, the vehicle motion is favorable for the assessment of concentrations behind a moving object, because the ecological indicators at successive distances behind the exhaust system achieve better parameters in most points than in a stationary test.

The paper presents the investigations of exhaust emissions under actual operation of two rail vehicles: a track geometry vehicle and a clearance vehicle. The environmental assessment of this type of objects is difficult due to the necessity of adapting the measurement equipment and meeting the safety requirements during the tests (particularly regarding the distance from the overhead electrical lines). The authors have proposed and developed a unique research methodology, based on which a detailed exhaust emissions analysis (CO, HC, NO_x, and PM) was carried out. The complex assessment included the unit and on-track exhaust emissions. In the analyses, the authors also included the operating conditions of the powertrains of the tested machinery. The obtained environmental indexes were referred to the homologation standards, according to which the vehicles were approved for operation. Due to the nature of operation of the tested vehicles, the authors carried out a comprehensive environmental assessment in the daily and annual approach as well as in the aspect of their operation as combined vehicles, which is a novel approach to the assessment of the environmental performance of this type of objects.

The exhaust emission standards in force in various parts of the world for off-road vehicles are becoming more and more stringent. Therefore, research on the compounds of harmful exhaust fumes emitted by vehicles of this category is constantly being researched and activities aimed at limiting them...

The article presents issues related to the assessment of concentrations of harmful substances in the exhaust gas cloud behind a compression-ignition passenger vehicle. The introduction discusses the subject of optical measurement methods and refers to Lambert Beer's law describing the phenomenon of absorption of electromagnetic radiation when passing through a partially absorbing and scattering medium. The vehicle used during the tests was characterized by a four-cylinder drive unit with a maximum power of 110 kW at 4000 rpm and a maximum torque of 320 Nm at 2000 rpm. The vehicle was type-approved in accordance with the Euro 4 standard. Exhaust gas dispersion tests behind the vehicle were carried out both in stationary conditions (a specially prepared laboratory stand) and in real operating conditions. PEMS testing equipment was used for this type of measurements. During the measurements, concentrations of harmful exhaust gas compounds were analyzed in relation to the distance of the measuring probe from the exhaust system. In stationary conditions, the influence of the engine speed on the dispersion of pollutants was also studied. The tests carried out show that the concentrations obtained behind a moving vehicle significantly decrease with the distance of the measuring probe, and their dispersion in most cases is much smaller than in the case of stationary tests. This is the basis for recognizing that thanks to this, it is possible to analyze the concentrations obtained and conduct tests using the emission gate.

Given the increase in air traffic, the main challenges in aircraft design are in-flight emissions and noise heard by the community. These problems have thus far been solved by incremental improvements in aerodynamics, engine technology and operation. To dramatically reduce aviation’s carbon footprint towards an environmentally friendly air transport system, alternative propulsion concepts are one of the promising areas of research and first applications. In this context, the goal of integrating a hybrid-electric powertrain with a suitable airframe is to increase efficiency while reducing in-flight emissions, reduce noise for the community, drive down direct operating costs and increase reliability. This article presents an inexpensive approach to testing small, manned aircraft with a hybrid fuel–electric propulsion system. First, the design assumptions of the research flying platform are presented. Next, modifications of the existing two-seater glider are analyzed. These modifications are necessary to fit the fuel–electric hybrid propulsion system. The analysis allows us to select the elements of an appropriate hybrid electric system. It also shows that this type of small experimental propulsion system can be mounted on a two-seater aerobatic glider without significant structural modifications and still comply with the most important points of the Certification Standard-22. Finally, the design of the ground test stand for the propulsion system is described. It is believed that a thorough examination of the propulsion system on the ground will reveal both the advantages and disadvantages of the system. This should facilitate the successful installation of the system under study on a flying aircraft.