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High cycle-to-cycle variations (CTCV) in a Hydrogen-Fueled Internal Combustion Engine (H2-ICE), especially in the lean-burn condition, not only lower the engine’s efficiency but also increase emissions and torque variations. High CTCV are mainly due to the variations in: mixture motion within the cylinder at the time of spark, amount of air and fuel fed to the cylinder, and mixing of the fresh mixture and residual gases within the cylinder during each cycle. In this article, multiple cycle-based methodologies were compared and analyzed specifically for H2-ICEs based on systematic experimentation. The experimental test campaign was performed on a Port Fuel Injection (PFI) H2-ICE designed by PUNCH Torino and data is processed with MATLAB. A MATLAB code is also proposed as a tool for comparing multiple methodologies for the analysis of CTCV specifically for H2-ICE.

In the perspective of a reduction of emissions and a rapid decarbonisation, especially for compression ignition engines, hydrogen plays a decisive role. The dual fuel technology is perfectly suited to the use of hydrogen, a fuel characterized by great energy potential. In fact, replacing, at the same energy content, the fossil fuel with a totally carbon free one, a significant reduction of the greenhouse gases, like carbon dioxide and total hydrocarbon, as well as of the particulate matter can be obtained. The dual fuel with indirect injection of gaseous fuel in the intake manifold, involves the problem of hydrogen autoignition. In order to avoid this difficulty, the optimal conditions for the injection of the incoming mixture into the cylinder were experimentally investigated. All combustion processes are carried out on a research engine with optical access. The engine speed has is set at 1500 rpm, while the EGR valve is deactivated.

Given the spread of natural gas engines in low-term toward decarbonization and the growing interest in gaseous mixtures as well as the use of hydrogen in Heavy-Duty (HD) engines, appropriate strategies are needed to maximize thermal efficiency and achieve near-zero emissions from these propulsor systems. In this context, some phenomena related to real-world driving operations, such as engine cut-off or misfire, can lead to inadequate control of the Air-to-Fuel ratio, key factor for Three-Way Catalyst (TWC) efficiency. Goal of the present research activity is to investigate the performance of a bio-methane-fueled HD engine and its Aftertreatment System (ATS), consisting of a Three-Way Catalyst, at different Air-to-Fuel ratio. An experimental test bench characterization, in different operating conditions of the engine workplan, was carried out to evaluate the catalyst reactivity to a defined pattern of the Air-to-Fuel ratio.

The transport of goods and people by sea, today, must meet the need to reduce the consumption of fuel oil. In addition, it has to ensure operational reliability and vessel availability, to reduce maintenance costs and comply with emission legislation. To this end, it is necessary to apply a marine engine combustion control system already widely used in engines for land transport. This will allow the ship's engines to operate reliably and in compliance with the best performance for which it was designed. The combustion control could also ensure a more balanced operation of the cylinders and reduce the torsional vibrations of the entire engine, as well as the management of the engine according to the adopted fuel: diesel, dual fuel, methanol, ammonia. Generally, the control of combustion in engines is carried out through the use of pressure sensors that face directly into the combustion chamber.

Converting spark ignition (SI) engines to H2 fueling is an attractive route for achieving zero carbon transportation and solving the legacy fleet problem in a future scenario in which electric powertrains will dominate. The current paper looks at a small size passenger car in terms of vehicle dynamics and electronic control unit (ECU) remapping requirements, in the hypothesis of using H2 as a gasoline replacement. One major issue with the use of H2 in port fuel injection (PFI) engines is that it causes reduced volumetric efficiency and thus low power. The vehicle considered for the study features turbocharging and therefore complete or partial recuperation of lost power is possible. Other specific requirements such as injection phasing were also under scrutiny, especially as PFI was hypothesized to maximize cost effectiveness. A 0D/1D model was used for simulating engine running characteristics as well as vehicle dynamics.

Electrification of transport, together with the decarbonization of energy production are suggested by the European Union for the future quality of air. However, in the medium period, propulsion systems will continue to dominate urban mobility, making mandatory the retrofitting of thermal engines by applying combustion modes able to reduce NOx and PM emissions while maintaining engine performances. Low Temperature Combustion (LTC) is an attractive process to meet this target. This mode relies on premixed mixture and fuel lean in-cylinder charge whatever the fuel type: from conventional through alternative fuels with a minimum carbon footprint. This combustion mode has been subject of numerous modelling approaches in the engine research community. This study provides a theoretical comparative analysis between multi-zone (MZ) and Transported probability density function (TPDF) models applied to LTC combustion process.

In this work, a dynamic 0-D electro-thermal model of a lithium-polymer battery for automotive applications is presented. The model predicts the battery temperature during its charging/discharging phases under different environmental and operating conditions, by considering the requested power or current, the coolant flow rate and its temperature as model inputs. The model was first validated with experimental data carried out at the test bench where only the convective heat transfer between the battery and the ambient air was considered. The accuracy of the internal heat generation model was experimentally assessed for different current discharge rates. Then, a liquid cooling system was designed on purpose, assembled, and installed on the battery at the test bench for the improvement of the model predictions in liquid convection conditions.

The growing concern about Greenhouse Gas (GHG) emissions led institutions to further reduce the limits on vehicle-related CO2 emissions. Therefore, car manufacturers are developing vehicles with low environmental impact, like Hybrid-Electric Vehicles (HEVs), which in the series architecture employ an Internal Combustion Engine (ICE) coupled with an electric generator for battery recharging, thus extending the range of a Battery Electric Vehicle (BEV). For this kind of application, small four-stroke Spark Ignition (SI) engines are preferred, as they are a proven and reliable solution to increase the driving range with very low environmental impact. In series hybrid-electric powertrains, the ICE is decoupled from the drive wheels, then it can operate in a steady-state high-efficiency working point, regardless of the power required by the mission profile. The benefits of lean combustion can be exploited to increase efficiency and reduce CO2 and NOx emissions.

Hydrogen is an energy vector with low environmental impact and will play a significant role in the future of transportation. Converting a spark ignition (SI) engine powered vehicle to H2 fueling has several challenges, but was overall found to be feasible with contained cost. Fuel delivery directly to the cylinder features numerous advantages and can successfully mitigate backfire, a major issue for H2 SI engines. Within this context, the present work investigated the specific fuel system requirements in port- (PFI) and direct-injection (DI) configurations. A 0D/1D model was used to simulate engine operating characteristics in several working conditions. As expected, the model predicted significant improvement of volumetric efficiency for DI compared to the PFI configuration. Boosting requirements were predicted to be at levels quite close to those for gasoline fueling.

In order to reduce fuel consumption and polluting emissions from engines, alternative fuels such as hydrogen could play an important role towards carbon neutrality. Moreover, dual-fuel (DF) technology has the potential to offer significant improvements in carbon dioxide emissions for transportation and energy sectors. The dual fuel concept (natural gas/diesel or hydrogen/diesel) represents a possible solution to reduce emissions from diesel engines by using low-carbon or carbon-free gaseous fuels as an alternative fuel. Moreover, DF combustion is a possible retrofit solution to current diesel engines by installing a PFI injector in the intake manifold while diesel is injected directly into the cylinder to ignite the premixed mixture. In the present study, dual fuel operation has been investigated in a single cylinder research engine.

The urban mobility electrification has been proposed as the main solution to the vehicle emission issues in the next years. However, internal combustion engines have still great potential to decarbonize the transport sector through the use of low/zero-carbon fuels. Alcohols such us methanol, have long been considered attractive alternative fuels for spark ignition engines. They have properties similar to those of gasoline, are easy to transport and store. Recently, great attention has been devoted to gaseous fuels that can be used in existing engine after minor modification allowing to drastically reduce the pollutant emissions. In this regard, this study tries to provide an overview on the use of alternative fuels, both liquid and gaseous in spark ignition engines, highlighting the benefits as well as the criticalities. The investigation was carried out on a small displacement spark ignition engine capable to operate both in port fuel and direct injection mode.

The forthcoming introduction of the EURO VII regulation requires urgent strategies and solutions for the reduction of sub-23 nm particle emissions. Although they have been historically considered as particulate matter-free, the high interest for Natural Gas (NG) Heavy-Duty engines in the transport sector, demands their compliance with the new proposed regulations. In order to obtain high conversion of gas pollutants and a strong abatement of the emitted particles, the use of Particle Filters in NG aftertreatment (CPF) in conjunction with the Three-Way Catalyst (TWC) may represent an attractive and feasible solution. Performances of a cordierite filter were explored through an extensive experimental campaign both in Steady-State conditions and during transient engine maneuvers that involved a whole analysis of the emitted particles in terms of number and mass.

Hydrogen Internal Combustion Engines (H2-ICEs) are subject to increased attention thanks to their extremely low criteria pollutant emission and near-zero CO2 tailpipe emissions. However, to further minimize exhaust emissions and increase the efficiency of a H2-ICE, it is important to carefully control the relative air-fuel ratio of operation, i.e. Lambda (λ), which will lead in turn to an optimal combustion process. The precise λ control mainly relies upon the methodology to calculate λ on board of the engine, where the availability of reliable sensors specifically-developed for hydrogen combustion is currently limited. In this article, a comparative analysis of different methodologies for the calculation of λ is performed, comparing four methodologies: exhaust gas analysis through a Spindt-Brettschneider approach (λEMI), raw Universal Exhaust Gas Oxygen (λR-UEGO), processed Universal Exhaust Gas Oxygen (λP-UEGO) and speed-density (λSD) outputs.

Increasingly stringent pollutant and CO2 emission standards require the car manufacturers to investigate innovative solutions to further improve the fuel economy and environmental impact of their fleets. Nowadays, NOx emissions standards are stringent for spark-ignition (SI) internal combustion engines (ICEs) and many techniques are investigated to limit these emissions. Among these, an extremely lean combustion has a large potential to simultaneously reduce the NOx raw emissions and the fuel consumption of SI ICEs. Engines with pre-chamber ignition system are promising solutions for realizing a high air-fuel ratio which is both ignitable and with an adequate combustion speed. In this work, the combustion characteristics of an active pre-chamber system are experimentally investigated using a single-cylinder research engine. The engine under exam is a large bore heavy-duty unit with an active pre-chamber fuelled with compressed natural gas.

Hybrid electric vehicles are a suitable solution for the transition from fossil fuels-based transportation to electric mobility. They have the benefits of zero-emissions operation when only the electric engine is used preventing the typical range anxiety of full-electric vehicles. Also, they can have a low battery pack capacity and weight thanks to the continuous recharge from the internal combustion engine that becomes the only responsible for exhaust emissions. A practical solution to limit the combustion engine emissions is represented by the range extender configuration, where the engine works at a fixed operating point with the highest efficiency serving uniquely as a battery charger. In the face of the current world situation and future changes, research for alternative energy sources is crucial. Hydrogen can be used as an alternative fuel for common internal combustion engines; moreover, it has the great advantage of high efficiency (about 44%).

In the context of increasing efforts towards zero emissions transport, hydrogen represents a valid alternative to electric powertrains. Spark ignition (SI) engines are well suited for this alternative fuel and its specific application requires relatively minor changes with respect to added components. Limited range is one of the main issues with hydrogen as an energy source for transportation, due to its low energy density. The present study looked at the possibility of converting a small size passenger car powered by a turbocharged SI unit to hydrogen fueling. Taking the electric version of the vehicle as benchmark, the initial evaluation of the hydrogen SI alternative appears feasible with an additional gas container comparable in size to the gasoline tank. As a result, further investigation was aimed at actual engine operation in port fuel injection mode, with a focus on rated power and injection phasing effects.

Direct injection spark ignition engines represent an effective technology to achieve the goal of carbon dioxide emission reduction. Further reduction of the carbon footprint can be achieved by using carbon-neutral fuels. Oxygenated alcohols are well consolidated fuels for spark ignition engines providing also the advantages of knock resistance and low soot tendency production. Methanol and ethanol are possible candidates as alternative fuels to gasoline due to their similar properties. In this study a blend at 25 % v/v of ethanol in gasoline (E25) and a blend with 80% gasoline, 5 % v/v ethanol and 15% v/v of methanol (GEM) were tested. These blends were considered since E25 is already available at fuel pump in some countries. The GEM blend, instead, could represent a valid alternative in the next future. Experiments were carried out on a high performance, turbocharged 1.8 L direct injection spark ignition engine over the Worldwide Harmonized Light Vehicles Test Cycle.

The application of an alternative fuel such as hydrogen to internal combustion engines is proving to be an effective and flexible solution for reducing fuel consumption and polluting emissions from engines. An easy to use and immediate application solution is the dual fuel (DF) technology. It has the potential to offer significant improvements in carbon dioxide emissions from light compression ignition engines. The dual fuel concept (natural gas / diesel or hydrogen / diesel) represents a possible solution to reduce emissions from diesel engines by using low-carbon or carbon-free gaseous fuels as an alternative fuel. Moreover, DF combustion is a possible retrofit solution to current diesel engines by installing a PFI injector in the intake manifold while diesel is injected directly into the cylinder to ignite the premixed mixture. In the present study, dual fuel operation has been investigated in a single cylinder research engine.

Nowadays, the stricter regulations in terms of emissions have limited the use of diesel engines on urban roads. On the contrary, for marine and off-road applications the diesel engine still represents the most feasible solution for work production. In the last decades, dual fuel operation with methane supply has been widely investigated. Starting from previous studies on a research engine, where diesel-methane dual fuel combustion has been deepened both experimentally and numerically with the aid of a CFD code, the authors implemented and tested a kinetic mechanism. It is obtained from the combination of the well-established GRIMECH 3.0 and a detailed scheme for a diesel surrogate oxidation. Moreover, the Autoignition-Induced Flame Propagation model, included in the ANSYS Forte® software, is applied because it can be considered the most appropriate model to describe dual fuel combustion.

The battery efficiency is strongly affected by the operating temperature, granting the best performance in a limited range. Great attention is given to the design and the testing of materials for the battery heat dissipation. In the present study, the thermal behavior of a Li-polymer cell, which is part of a battery pack for electric vehicles, is investigated. The cell is provided with different coatings of carbon, graphene, and silicone, used in turn, to dissipate the heat generated during the operation in natural convection. The coating is placed only on one side of the battery while the other one is inspected via thermal imaging. Optical diagnostics in the infrared band are used to evaluate the bi-dimensional distribution of the battery surface temperature and the effect of the coatings. Different operating conditions are tested by varying the current demand.