Analysis of the Exhaust Emissions of Hybrid Vehicles for the Current and Future RDE Driving Cycle

Hybrid vehicles account for the largest share of new motor vehicle sales in Europe. These are vehicles that are expected to bridge the technological gap between vehicles with internal combustion engines and electric vehicles. Such a solution also makes it possible to meet the limits of motor vehicle emissions, at a time when it is particularly important to test them under actual traffic conditions. This article analyzes the impact of the length of the test routes in relation to current, but also future regulations of approval standards. Three routes of post-phase composition (urban, rural, motorway) with lengths of about 30, 16 and 8 km were selected for the study. Measurements of the main emission components were made using portable emission measurement systems (PEMS), and exhaust emissions were determined using the moving average window (MAW) method. Analysis of the obtained results led to the conclusion that the current requirements for the RDE test (in particular, the duration of the test) enforce a length of each part of 32 km. Reducing the test to 60–90 min causes the individual phases to last 16 km, and the main advantage of such a solution is the very strong influence of the cold start phase on the emission results in the urban phase. Future declarations by lawmakers to drastically reduce the length of the test phases to 8 km will force hybrid vehicles to be tested largely using the internal combustion engine. This will be the right thing to do, especially in the urban phase, as now in addition to a significant reduction in the engine warm-up phase, manufacturers will have to take into account that such an engine thermal condition can also occur in the rural phase

Plug-in Hybrid Ecological Category in Real Driving Emissions

Transportation, as one of the most growing industries, is problematic due to environmental pollution. A solution to reduce the environmental burden is stricter emission standards and homologation tests that correspond to the actual conditions of vehicle use. Another solution is the widespread introduction of hybrid vehicles—especially the plug-in type. Due to exhaust emission tests in RDE (real driving emissions) tests, it is possible to determine the real ecological aspects of these vehicles. The authors of this paper used RDE testing of the exhaust emissions of plug-in hybrid vehicles and on this basis evaluated various hybrid vehicles from an ecological point of view. An innovative solution proposed by the authors is to define classes of plug-in hybrid vehicles (classes from A to C) due to exhaust emissions. An innovative way is to determine the extreme results of exhaust gas emission within the range of acceptable scatter of the obtained results. By valuating vehicles, it will be possible in the future to determine the guidelines useful in designing more environmentally friendly power units in plug-in hybrid vehicles

Evaluation of ecological extremes of vehicles in road emission tests

New testing procedures for determining road emissions of exhaust pollutants for passenger vehicles were established in 2018. New road testing procedures are designed to determine actual exhaust emissions, which may not always reflect laboratory emissions. Test procedures for the emission of pollutants in real traffic conditions are divided into four stages. The latest research on the emission of pollutants from motor vehicles in road traffic conditions, carried out using mobile measuring systems, reflects the actual ecological state of vehicles. The article compares the results of exhaust emissions obtained in road tests using the latest legislative proposals for passenger cars. Then, an attempt was made to determine the engine operating parameters in which exhaust road emission would be the lowest. Solution scenarios were defined as part of permissible changes to dynamic parameters that are included in European legislation on RDE testing. For this purpose, an optimization tool was used, allowing on the basis of given input data to determine the minimum objective function, defined as the smallest emission value of individual harmful compounds. The results of the exhaust gas emissions in the RDE test were used to determine the road emissions of individual harmful compounds. A thorough analysis of the emission intensity of individual compounds has shown that it is possible to approximate such values using functional rela-tionships or adopting them as a constant value. This division was used to determine the extremes (in this case the minima) of the objective function (minimum road emissions of harmful exhaust components). This task resulted in obtaining (within the permissible tolerances of all driving parameters and durations of individual road test sections) the value of exhaust emissions in the range from 26% to 81% lower than in the actual road test. This means that there is a tolerance range, where you can obtain the value of emissions in road tests. As a result, you can use the process of determining the minimum emissions tests RDE calibration of the drive units already at the stage of preparation so that in the real traffic conditions characterized by the lowest exhaust emissions

Analysis of the Exhaust Emissions of Hybrid Vehicles for the Current and Future RDE Driving Cycle

Hybrid vehicles account for the largest share of new motor vehicle sales in Europe. These are vehicles that are expected to bridge the technological gap between vehicles with internal combustion engines and electric vehicles. Such a solution also makes it possible to meet the limits of motor vehicle emissions, at a time when it is particularly important to test them under actual traffic conditions. This article analyzes the impact of the length of the test routes in relation to current, but also future regulations of approval standards. Three routes of post-phase composition (urban, rural, motorway) with lengths of about 30, 16 and 8 km were selected for the study. Measurements of the main emission components were made using portable emission measurement systems (PEMS), and exhaust emissions were determined using the moving average window (MAW) method. Analysis of the obtained results led to the conclusion that the current requirements for the RDE test (in particular, the duration of the test) enforce a length of each part of 32 km. Reducing the test to 60–90 min causes the individual phases to last 16 km, and the main advantage of such a solution is the very strong influence of the cold start phase on the emission results in the urban phase. Future declarations by lawmakers to drastically reduce the length of the test phases to 8 km will force hybrid vehicles to be tested largely using the internal combustion engine. This will be the right thing to do, especially in the urban phase, as now in addition to a significant reduction in the engine warm-up phase, manufacturers will have to take into account that such an engine thermal condition can also occur in the rural phase

Experimental Investigation on Knock Characteristics from Pre-Chamber Gas Engine Fueled by Hydrogen

Hydrogen-fueled engines require large values of the excess air ratio in order to achieve high thermal efficiency. A low value of this coefficient promotes knocking combustion. This paper analyzes the conditions for the occurrence of knocking combustion in an engine with a turbulent jet ignition (TJI) system with a passive pre-chamber. A single-cylinder engine equipped with a TJI system was running with an air-to-fuel equivalence ratio λ in the range of 1.25–2.00, and the center of combustion (CoC) was regulated in the range of 2–14 deg aTDC (top dead center). Such process conditions made it possible to fully analyze the ascension of knock combustion until its disappearance with the increase in lambda and CoC. Measures of knock in the form of maximum amplitude pressure oscillation (MAPO) and integral modulus of pressure oscillation (IMPO) were used. The absolute values of these indices were pointed out, which can provide the basis for the definition of knock combustion. Based on our own work, the MAPO index > 1 bar was defined, determining the occurrence of knocking (without indicating its quality). In addition, taking into account MAPO, it was concluded that IMPO > 0.13 bar·deg is the quantity responsible for knocking combustion

Load Capacity of Nickel–Metal Hydride Battery and Proton-Exchange-Membrane Fuel Cells in the Fuel-Cell-Hybrid-Electric-Vehicle Powertrain

This article investigates the impact of loading on the hybrid powertrain of the FCAT-30 model, equipped with a proton-exchange-membrane fuel cell (PEMFC) and a nickel–metal hydride (NiMH) battery. This study involves analyzing structural component performance based on voltage and current measurements of the fuel cell, battery, and powertrain. Tests conducted under different load conditions reveal significant differences in battery current and fuel-cell voltage, highlighting the crucial role of the battery in the powertrain. External loading induces cyclic operation of the fuel cell, generating peak power. The energy balance analysis demonstrates that, under no-load conditions, the vehicle consumes 37.3% of its energy from the fuel cell, with a total energy consumption of 3597 J. Under load, the energy from the battery is significantly utilized, resulting in a constant fuel-cell share of approximately 19%, regardless of the vehicle’s load. This study concludes that the battery predominantly drives the powertrain, with the fuel cell acting as a secondary energy source. These findings provide valuable insights into the power distribution and energy balance in the hybrid powertrain. Using a load driving profile reduced the fuel-cell-stack energy contribution by 6.85% relative to driving without an external load

Cold start emissions of passenger cars with gasoline and diesel engines in Real Driving Emissions tests

Modernization of passenger cars and constant development of existing legislation lead to a reduction of exhaust emissions from these vehicles. In accordance with package 3 of the RDE test procedure, the European Commission has extended testing methods by including exhaust emissions during a cold start. The article compares the research results on the impact of ambient temperature during the cold start of spark-ignition and compression-ignition engines in road emission tests. The tests were carried out in line with the requirements of the RDE test procedure for passenger cars meeting the Euro 6d-Temp emissions standard. The obtained results were analyzed, i.e. there were compared the engine and vehicle operation parameters and the values of road exhaust emissions, during the cold start of gasoline and diesel engines at the ambient temperature of approximately 25°C. The summary presents the share of cold start phase of a passenger car (at the ambient temperature of around 25°C) for each exhaust emission compound in the urban part of the test, and in the entire RDE test, depending on the engine type used

Analysis of particle emissions of passenger cars in RDE tests

The main issues addressed by the article are dimensional analysis of solid particles emitted by passenger cars operating in real driving conditions. It is a part of the current research trend focused on searching pro-ecological solutions related to determining the environmental impact of road transport. Special emphasis was placed on the comparison of the ecological parameters of passenger cars fuelled with petrol (conventional and hybrid) and diesel. All tests were carried out in accordance with the applicable requirements of the European Union. This approach will expand the knowledge base on the ecological properties of vehicles moving in urban, rural area and on highways

Analysis of particle emissions of passenger cars in RDE tests

The main issues addressed by the article are dimensional analysis of solid particles emitted by passenger cars operating in real driving conditions. It is a part of the current research trend focused on searching pro-ecological solutions related to determining the environmental impact of road transport. Special emphasis was placed on the comparison of the ecological parameters of passenger cars fuelled with petrol (conventional and hybrid) and diesel. All tests were carried out in accordance with the applicable requirements of the European Union. This approach will expand the knowledge base on the ecological properties of vehicles moving in urban, rural area and on highways