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Exhaust gas aftertreatment systems can, under certain conditions, create undesired chemical species as a result of their elimination reactions. A prime example of this is ammonia (NH3), which is not formed in the combustion reaction, but which can be formed within a three-way catalyst (TWC) when physicochemical conditions permit. The elimination of NOx in the TWC thus sometimes comes at the cost of significant emissions of NH3. Ammonia is a pollutant and a reactive nitrogen compound (RNC) and NH3 emissions should be analyzed in this context, alongside other RNC species. Examination of the literature on the subject published over the past two decades shows that ammonia, a species which is currently not subject to systematic emissions requirements for road vehicles in any market, is often identified as forming the majority of the RNC emissions under a range of operating conditions.

This paper discusses the legislative situation regarding type approval of plug-in hybrid vehicles (also known as off-vehicle charging hybrid-electric vehicles, OVC-HEV) in the range of exhaust emissions and fuel consumption. A range of tests were conducted on two Euro 6d-complaint OVC-HEVs to quantify emissions. Procedures were based on EU legislative requirements. For laboratory (chassis dyno) testing, two different test cycles and three different ambient temperatures were used for testing. Furthermore, in some cases additional measurements were performed, including measurement of emissions of particulate matter and continuous analysis of regulated and unregulated pollutants in undiluted exhaust. Consumption of electrical energy was also monitored. On-road testing was conducted on the test vehicle tested on the chassis dyno in the tests mentioned above, as well as on a second OVC-HEV test vehicle.

Increasing the efficiency of an internal combustion engine is possible thanks to the use of an extended expansion stroke relative to the suction stroke. This solution was first patented by James Atkinson in the construction of an internal combustion engine in the XIX century. The article presents a solution using the principle of extended expansion stroke. In the design of Szymkowiak's proprietary engine, a conceptual crank-piston system was used with additional elements enabling the Atkinson cycle to be obtained. A 3D model was created based on which forces acting in the system were tested. The generated piston path profile allowed to characterize its movement. A mobile mesh of the combustion chamber was created, thanks to this a detailed CFD simulation was performed in the AVL Fire software. An important criterion was the assumption of adiabatic characteristics of processes during the combustion.

The paper concerns the analysis of the combustion and exhaust emission phenomena in a direct gasoline dual injection system of a SI engine for various symmetrical injector placement parameters in the combustion chamber. Achieving a good combustion process is shaped by the direct fuel injection process, whose parameters vary. The novel direct injection system, which deploys two direct injectors mounted symmetrically, was subjected to this simulative research. This article focuses on the aspect of spatial and angular position of injectors in order to perform injection and achieve fuel combustion. The injector's pseudo-optimal location has been presented along with several changed positions (3 values of injector inset: 0, 1 and 2 mm, 3 values of injector distance from the cylinder axis: 16, 17, 18 mm and 3 values of angle between injector and the cylinder axis: 42.5, 45 and 47.5 degrees - 27 combinations altogether).

The benefits associated with the use of oxygen-containing diesel fuels in passenger cars are quite well described in the literature. This work describes the results of an 18-meter EEV city bus fueled with diesel fuel with the addition of 10% v/v of triethylene glycol dimethyl ether. This compound was chosen because it was effective in reducing exhaust emissions from light duty diesel vehicles. Emission tests (CO, HC, NOx and PM) of the city bus were performed over SORT (Standardized On-Road Tests) cycles using portable exhaust gas analyzers - PEMS. Significant differences in the emission of exhaust components were observed in individual SORT cycles. The level of road emissions reduced as the traffic smoothness increased, i.e. from the SORT 1 to SORT 3 cycle. The largest reduction in bus emissions associated with the use of the oxygenated additive (triethylene glycol dimethyl ether) applies to carbon monoxide and ranges from 50% for the SORT 3 cycle up to 90% for the SORT 1.

Lean air-gas mixture combustion systems seem to be very promising solutions for IC engines in terms of lower emission indexes and higher thermal efficiency, especially in part-load operation. The main problem however is the necessity to provide the bigger activation energy for ignition of lean and very lean mixtures. In several publications and in research performed by the authors of this paper it has been confirmed, that the implementation of turbulent jet ignition (TJI) results in significantly faster inflammation of lean CNG/air mixture due to the improvement in on-ignition mechanism. The TJI-system consists of two chambers connected with nozzles. The orifices generate complex charge movement and decrease significantly the charge homogeneity in the pre-chamber, interrupting therefore first ignition process.

The article describes issues related to the impact of transport means on the environment. These issues are currently very popular due to the increasing public awareness of the negative environmental and health effects associated with air pollution. The authors estimated specific emissions in passenger-kilometers, considering a domestic travel by air and road transport. The analyzed route is located between the Polish cities: Gdansk and Cracow. The selected route is long by domestic travel standards, but in that travel distance, the road transport is still competitive to the air transport. Selected means of transport belong to popular representatives in their classes. As a road vehicle, the authors selected a modern passenger car powered by a spark ignition engine, meeting the Euro 6 emission standard. Among the passenger aircrafts, an object which belongs small jet aircrafts, propelled with Rolls-Royce Tay 611C jet engines was selected.

The share of hybrid and electric powertrains in the market increases continuously. In local driving conditions, electric vehicles are zero-emission, yet their regular use requires an infrastructure allowing the recharging of high-voltage batteries. Hybrid vehicles also allow the use of the electric drive; however, when the high-voltage battery is low, a combustion engine is used to recharge it. Hybrid powertrains do not require any changes in the infrastructure, nor do they force any changes in the driver's habits. The use of a hybrid vehicle may, however, reduce the operating time of the combustion engine, thus contributing to the reduction of fuel consumption. This reduction of fuel consumption results from a specifically selected energy flow strategy in hybrid systems. This strategy was the focus of the research performed to identify the energy flow conditions in a hybrid drive system under driving conditions corresponding to the RDE test.

Non-plugin hybrids represent a technology with the capability to significantly reduce fuel consumption (FC), without any changes to refuelling infrastructure. The EU market share for this vehicle type in the passenger car segment was 3% in 2018 and this powertrain type remains of interest as an option to meet the European Union (EU) fleet average CO2 limits. EU legislative procedures require emissions limits to be met during the chassis dynamometer test and in the on-road real driving emissions (RDE) test, while official CO2/FC figures are quantified via the laboratory chassis dynamometer test only. This study employed both legislative test procedures and compared the results. Laboratory (chassis) dynamometer testing was conducted using the Worldwide Harmonised Light Vehicles Test Procedure (WLTP). On-road testing was carried out in accordance with RDE requirements, measuring the concentration of regulated gaseous emissions and the number of solid particles (PN).

Non-Road machines constitutes a large group of machines designed for various tasks and mainly using CI engines for propulsion. This category includes vehicles with drive systems of a maximum capacity of several kilowatts as well as with drives with a capacity of up to thousands of kilowatts depending on the purpose of the machine. Within this group, mobile machines referred to as NRMM (Non-Road Mobile Machinery) stand out. Numerous studies of scientific institutions in Europe and around the world have proven the differences between the exhaust emissions tested in type approval tests and the actual emissions in this group of vehicles. They result from differences in operating points (crankshaft speed and load) of engines during their operation. A big problem is also their considerable age and degree of wear. Approval standards themselves are less stringent than those of heavy-duty vehicles (HDVs), although the engines have similar design and performance.

European Union RDE (real driving emissions) legislation requires that new vehicles be subjected to emissions tests on public roads. Performing emissions testing outside a laboratory setting immediately raises the question of the impact of ambient conditions - especially temperature - on the results. In the spirit of RDE legislation, a wide range of ambient temperatures are permissible, with mathematical moderation (correction) of the results only permissible for ambient temperatures <0°C and >+30°C. Within the standard range of temperatures (0°C to +30°C), no correction for temperature is applied to emissions results and the applicable emissions limits have to be met. Given the well-known link between the thermal state of an engine and its emissions following cold start, ambient temperature can be of great importance in determining whether a vehicle meets emissions requirements during an RDE test.

This paper discusses the importance of the inclusion of emissions from the cold start event during legislative on-road tests on passenger cars (RDE - real driving emissions tests conducted under real-world driving conditions, as defined by EU legislation). Results from a recently-registered gasoline-powered vehicle are presented, with the main focus on the comparison of exhaust emission results: excluding/including the cold start during the initial phase of the RDE test. Cold start is the most challenging aspect of emissions control for vehicles with spark ignition engines and the inclusion of the cold start event in RDE test procedure has wide-ranging implications both for the testing process and compliance with RDE legislation via optimisation of aftertreatment systems and the engine calibration. In addition to some theoretical arguments, the results of an RDE-compliant test performed using the aforementioned procedures are presented.

In this study, two vehicles were tested under real driving conditions with gaseous exhaust emissions measured using a portable emissions measurement system (PEMS). One of the vehicles featured a hybrid powertrain with a spark ignition internal combustion engine, while the other vehicle featured a non-hybrid (conventional) spark ignition internal combustion engine. Aside from differences in the powertrain, the two test vehicles were of very similar size, weight and aerodynamic profile, meaning that the power demand for a given driving trace was very similar for both vehicles. The test route covered urban conditions (but did include driving on a road with speed limit 90 km/h). The approximate test route distance was 12 km and the average speed was very close to 40 km/h.

This paper presents a study of passenger cars in terms of emissions measurements in tests conducted under real driving conditions (RDE - Real Driving Emissions) by means of PEMS (Portable Emission Measurement System) equipment. A special feature of the RDE tests presented in this paper is that they were performed under Polish conditions and the specified parameters may differ from those in most other European Union countries. Emission correction coefficients have been defined, based on the test results, equal to the increase (or decrease) of driving emissions during the laboratory (‘chassis dyno’) test or during normal usage in relation to the EU emission standards (emission class) of the vehicle.

The paper describes the measurement of PM emission from an excavator engine under actual operating conditions. The exploration of the relations between the engine operating parameters and its emissions requires measurements under actual conditions of engine operation. The specificity of the emission measurements, PM in particular, requires technologically advanced measuring devices. The situation gets even more complicated when, beside the PM mass. The particle size distribution and number (PN) also need to be measured. An important technical issue is the difficulty in fitting the measurement equipment in/on the vehicle in operation (e.g. excavator), which is why the presented investigations were carried out in a laboratory under simulated operation. The laboratory technicians applied load to the engines through the excavator hydraulic system.

The paper presents results of the road tests of exhaust gas emissions of vehicles of different emission classes (Euro 4 and Euro 5, with different mileage), fuelled with compressed natural gas. The tests of exhaust emissions were conducted on parts of the road with different characteristics of the traffic intensity. For each phase of the tests, the characteristics of the test run and the value of exhaust gas emissions were determined. To measure the exhaust emission the Portable Emission Measurement System (PEMS) was used.

The tests related to the exhaust emissions from non-road vehicles are currently performed on a chassis dynamometer under the name of NRSC (ISO 8178) and NRTC. In light of the growing requirements related to the environment protection in transport the authors recommend determining the exhaust emissions through real vehicle operating conditions. The tests carried out under real operating conditions could be used for the process of optimization of future power trains of regular road vehicles and non-road vehicles. What is more, these tests should be taken into account in the works on the changes of the legislation related to the emission limits from combustion engines. The paper presents the results of the tests on the exhaust emissions from an agricultural harvester engine and a tractor engine in real operating conditions. The harvester operation during the test consisted in crops collection from the field and the tractor operation during the test consisted in plowing.

The aim of this work was a preliminary discernment of the possibility of application of Pd-Au-Ag-Ni-Co (non Pt) nanometric, powder alloy as an active part of a new PM filter. The hollow part structure of TiO2-x-RuO2-x has been proposed as the active layer on the catalyst support, composed of SiC. This structure is used in the catalyst technology. The washcoat of TiO2-x-RuO2-x has been obtained by the Flame Spray Pyrolysis Deposition method (FSPD). The influence of the preparation conditions such as: flow velocity, salt concentration, temperature and process atmosphere on the size and shape of TiO2-x-RuO2-x particles has been determined. The catalyst alloy contains nanoparticles of Pd-Au, which encapsulated the nanoparticles of Ag and Ni. Such prepared nano-particles containing noble metals or metals 4d (Ni, Co, Ag), show high tolerance to sulfur and good reversible properties. The atoms of Pd prefer five coordinated sites of Ti for adsorption.

One of the main issues in the development of diesel engines is the NOx emission while the chief cause for such emission is high nitrogen content in the air and high temperature of combustion. There is a variety of methods to reduce this particular emission. One of the most widespread is exhaust gas recirculation and one of the most recent is the application of Adblue additive into the exhaust gases as a reducing agent. There are also catalytic converters capable of reducing the said emission but their efficiency is as yet insufficient. One of the more daring related concepts is the elimination of nitrogen from the air supplied to the combustion chamber through the application of ceramic ionic conductors. The technology applied in the last method is a dynamically advancing trend in material engineering. The development in this field indicates that, soon, an oxygen generator useful in the automotive engineering will become a reality.

The paper presents a concept of improving the injection and spraying processes with the use of the oxygen dissolved in the diesel fuel and the results of experimental investigations carried out in order to verify it. The combustion process of the direct injection compression-ignition engine being normally performed at a high excess of combustion air factor for the whole engine operation range is affected by local deficiencies of oxygen inside the fuel sprays in a combustion chamber. This fact is one of the main reasons for forming the harmful compounds in exhaust gases such as CO, HC and PM. The aim of the presented concept is to improve the fuel spray atomization by the release of the oxygen previously dissolved in the fuel. The influence of dissolving the oxygen in the diesel fuel on the run of the combustion process and concentration toxic compounds in exhaust gas has been presented in the paper.