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The high complexity and large number of hybrid vehicle configurations make it difficult to analyse and evaluate the efficiency and emissions of their propulsion systems. This paper presents a novel mathematical formulation for estimating the gains of hybrid powertrain in the form of exhaust emissions and fuel efficiency. According to the defined energy flow diagram, the mathematical formulation of each emission or fuel consumption source is given as a function of the most influential parameter. The input data are obtained by measuring emissions under real driving conditions or on a test bench which are mandatory during vehicle type approval. This approach is suitable for use as a stand-alone method or as part of simulation software.

The main objectives for the design of modern PEM fuel cells are to ensure minimize costs and size and ensure operation at elevated power densities with minimized accumulation of water inside the flow fields. Currently, number of authors are dedicated to increasing the flow field complexity, resulting in higher performance but also elevated manufacturing costs. By minimizing the complexity of the flow field and avoiding complex 3D structures, the main candidate still remains the serpentine flow field due to favorable characteristics of low pressure drop and good water removal. Due to discrepancies found in literature, in this work, the focus is on investigation of the liquid water accumulation inside the flow field of PEM fuel cell using up- to-date numerical model and full-scale single cell geometry with active area of 25 cm2, experimentally and numerically using computational fluid dynamics modeling. The initial simulation model is calibrated using experimental data and later modified according to literature recommendations, outlining the influence of designs on water accumulation, resulting in significant performance improvement using simple geometry. The future goal of the research is upscaling the developed geometry for 50 cm2 active area and comparing the numerical results with experimentally obtained locally resolved current density distribution.

Developing more efficient and versatile marine power systems is important due to increasingly stringent emissions regulations. Without further action to reduce greenhouse gas emissions, the contribution of shipping will increase by 150% to 250% by 2050, reaching a share of 12% to 18% of global CO2 emissions. One way to achieve this is to transform the conventional power system and its energy management strategy into a hybrid system. The hybrid architecture itself is complex and broad enough, but not yet developed far enough for marine applications. The main argument for implementing a more complex system such as hybrid marine power system, is that additional options in energy management bring the operation of each energy source closer to its optimal operating point. This is especially important for internal combustion engines, which operate most of the time in the part-load range, where their efficiency can drop significantly. Today, the most common alternative energy source system is fuel cell technology with different types of fuel cells, batteries, and supercapacitors as energy storage systems. The objective of this research is to size and analyse one of the possible auxiliary power systems, namely a hydrogen PEM cell with its associated components. For this research, the model was developed using the AVL Cruise-M software package. The sizing is done according to the energy demand of the ferry operating on the local line. Fuel cells generate DC energy that is compatible with modern electric and hybrid naval architectures, and can be used in parallel, disconnectable configurations to meet the variable energy needs of the vessels. And, if renewable hydrogen is utilized, fuel cells are a true well- to-wake zero emission power source. By using the hybrid system, the specific fuel consumption on a given route could be reduced by about 5% compared to the case where only a diesel engine is used, and accordingly reduces exhaust emissions.

The goal of the EU Horizon 2020 RISE project 778307 “Hydrogen fuelled utility vehicles and their support systems utilising metal hydrides” (HYDRIDE4MOBILITY), is in addressing critical issues towards a commercial implementation of hydrogen powered forklifts using metal hydride (MH) basedhydrogen storageand PEM fuel cells, together with the systems for their refuelling at industrial customers facilities. For these applications, highspecific weightof the metallic hydrides has an added value, as it allows counterbalancing of a vehicle with no extra cost. Improving the rates of H2charge/discharge in MH on the materials and system level, simplification of the design and reducing the system cost, together with improvement of the efficiency of system “MH store-FC”, is in the focus of this work as a joint effort of consortium uniting academic teams and industrial partners from two EU and associated countries Member States (Norway, Germany, Croatia), and two partner countries (South Africa and Indonesia). The work within the project is focused on the validation of various efficient and cost-competitive solutions including (i) advanced MH materials for hydrogen storage and compression, (ii) advanced MH containers characterised by improved charge-discharge dynamic performance and ability to be mass produced, (iii) integrated hydrogen storage and compression/refuelling systems which are developed and tested together with PEM fuel cells during the collaborative efforts of the consortium. This article gives an overview of HYDRIDE4MOBILITY project focused on the results generated during its first phase (2017–2019).

The PEM fuel cell has been consider as ideal power supply for the lift trucks due to its high efficient and environment-friendly energy production. A new methodology has been proposed for optimal size selection of a PEM fuel cell-Battery hybrid energy system to fulfil load demands of a lift truck. The size of the PEM fuel cell and battery of a hybrid lift truck will heavily affect the overall performance of the vehicle, its fuel economy, battery duration and the fuel cell degradation. The present study concerns a multi-objective design exploration and optimisation of fuel cell size and battery capacity comparing hydrogen fuel consumption, fuel cell lifetime and battery state of charge. The PEM fuel cell-battery power pack have been determined according to the real driving load demand of a lift truck. The optimising method gives the correct dimensioning of the hybrid power system together with the optimization of the battery state of charge control strategy. An individually optimised Energy Management Strategy has to be consider for each application in order to fulfil the objectives of fuel efficiency, battery lifetime and fuel cell degradation. Based on the parameters of the power system, a genetic algorithm was adopted to optimize the parameters of the control algorithm, in order to improve efficiency and durability

Start-up and variable load operation of a 1 kW air-cooled stack is investigated via computational fluid dynamics (CFD) analysis. The results of the transient analysis indicate that the temperatures inside the air-cooled stack are up to 27 °C higher when compared to the temperatures on the outside walls of the bipolar plates and this indicates a requirement for development of a new method for PEM fuel cell operation to increase the relative humidity of the reactants internally and prevent membrane dehydration. The novelty of this work is the method for increasing the relative humidity along the active area of the cell by intentionally increasing the pressure drop across the flow field, resulting in higher performance of the cell.

This paper describes a hybrid system of PEM FC forklifts that use PEM fuel cells and a battery as a source of electricity. Hybrid systems consist of a fuel cell system, which is the primary energy source, and an energy storage system, ie a battery, which provides an additional source of electricity or power. The complete hybrid drive system includes a hydrogen supply system, a PEM fuel cells stack and its regulator, a DC voltage regulator, a battery, an energy management regulator, and the forklift itself. Based on the conducted techno- economic analysis, and the comparison of battery electric forklifts and forklifts with PEM fuel cells, it is shown that despite high capital costs, the use of forklifts with PEM fuel cells can reduce the total cost of ownership by 10%. Fuel-powered forklifts can reduce charging costs by up to 80% and require 75% less space compared to battery charging infrastructure. In addition, fuel cells provide constant power during shifts, while battery performance deteriorates in line with SOC reduction. Thanks to proven performance, short refueling time and the potential to increase productivity, fuel cells can compete with life-cycle batteries. Figure

This paper presents a forklift hybrid system using PEM fuel cells and a battery as power source. In the first part the basic characteristics and the working energy principle of fuel cell technology are presented. Then different types of hybrid drive trains used in forklift trucks are described. In the last part, the feasibility of using hydrogen-powered PEMFC fuel cells as an alternative energy source for the drive train of forklift trucks is evaluated from a technical and economic point of view. The total cost of ownership of both technologies is compared to determine the economic costs or benefits associated with each technology. Shorter refueling time and constant power output has reduced idle time and increased productivity, ultimately impacting the productivity related costs in such a way that the fuel cell option has better financial results than battery powered forklift trucks.

This paper investigates the performance and emissions of two stroke low speed marine diesel engines running on alternative fuels such as LNG, methanol, hydrogen, ammonia, and their combinations. The numerical simulation of two stroke low speed ma rine diesel engine performance is based on AVL Boost multi zone combustion model. Calibration and validation of the engine numerical model was performed according to the test results of the actual engine running on marine diesel oil. Simulations were conducted to determine whether the use of alternative fuels can meet the requirements of IMO Tier III regulations for the NOx concentration in exhaust gases. The obtained results show that the use of certain alternative fuels in the operation of two stroke low speed marine engines can reduce NOx and carbon dioxide emissions. All mentioned alternative fuels were optimized to reach the required 3.4 g/kWh of NOx emissions with some gains in power (Methane +7 kW, hydrogen +5 kW) and some loses in power (Diesel + methanol 15 kW, and ammonia + hydrogen 7 kW)

The development of new technologies and their application in marine systems has increased the complexity of propulsion systems. The increase in the number of ships within the merchant fleets has resulted in difficult monitoring of the condition of ships and the need for expertise in electronically controlled propulsion systems. The introduction of diagnostic systems enables easier analysis of operating parameters, and thus improves the efficiency of the marine energy system. The paper examines new diagnostic systems, one of which is a remote monitoring system applied to a marine engine during its operation. During the research, the most influential parameters of the tested engine were identified and its operation was analyzed. Conclusions were drawn on the advantages and disadvantages of the application of remote monitoring systems for marine engines and provided guidelines for determining the remote monitoring system of marine energy systems that should be installed in ships to increase energy efficiency.

Material handle vehicles are irreplaceable and widely used in the industry. In indoor operations and other conditions which have strict requirements, lift trucks, powered by lead-acid batteries, dominates. The weaknesses of battery modules are a short working time and a long charging time which result in cost increase. The solution is the high efficiency, zero emission energy produced with fuel cell. In this article, analysis and optimization of the fuel cell/battery hybrid system were provided. For the specific application, an optimal battery capacity and fuel cell stack power were determined.

Today’s propulsion technology in sea and road transport is driven by legislations focused on emission reduction. This has even higher importance in highly populated cities and harbors where the number of commercial vessels and vehicles increases with population size. They are typically diesel fueled, and in city areas and harbors during maneuvering, operate at low speeds and loads. This results in significant greenhouse gases and exposure to diesel exhaust, which is comprised primarily of particulate matter and oxides of nitrogen. Hydrogen fueled polymer electrolyte membrane (PEM) fuel cell technology is a technology to reduce the environmental impact of the transport sector. Life cycle analysis of fuel cell vehicles as well as optimum integration strategy of the PEM fuel cell in hybrid system was studied in this article. The PEM fuel cell was designed to reduce the additional pollution created by auxiliary loads. Several simulations were performed with fully loaded cargo weight and with all possible auxiliary loads in different cycles. By integrating PEM fuel cell to cover auxiliary power and simulating it on realistic driving cycle, the shift of powering the auxiliary loads from internal combustion engine to PEM fuel cell has shown reduction in diesel fuel consumption as well as CO2 reduction.

The conducted research gives an insight into the issue of disproportion of the exhaust emissions of vehicles with diesel engines under the conditions of exploitation concerning the approved values. Under realistic operating conditions, costly failures on emission control systems occur, as a rule, either by replacement of components of questionable quality or by the complete elimination of components. Emissions were measured on 6 different vehicles with Euro 3, 4 and 5 standards, with correct and faulty emission control components. The results obtained show significant increases in NOx emissions of 58% for Euro 5 to 73% for Euro 4 and increases of 228% over homologated values with Cf = 2.1, CO emissions in case of failure increased by 228% at Euro3 up to as much as 781% at Euro5. Guidelines are provided on how to control some parts of the emission control system

Techno-economic analysis of various stand-alone photovoltaic wind turbine energy systems is made. Three different energy storage options were compared namely (i) battery, (ii) hydrogen system and (iii) combined battery and hydrogen system. Each of the three energy storage options was simulated with five different system configurations. Overall, 15 different hour by hour simulation were performed using Matlab. The hourly wind speed and solar insolation input data, location Split Croatia, were acquired from the national meteorological service. The techno-economic analysis consists of annual life cycle analysis, levelized cost of energy analysis and overall system efficiency. The results show that using both solar and wind for energy production and using both battery and hydrogen for energy storage is the economically more viable solution than using only one energy source and one form of energy storage. Solar/wind/battery/hydrogen system configuration resulted in 0.509 €/kWh, while solar/battery and wind/battery resulted in 0.945 €/kWh and 2.496 €/kWh levelized cost of energy, respectively.

Because of the aspiration for a better, more powerful engine with highest efficiency and lower fuel consumption, new ideas and mechanisms are constantly being developed to improve and enhance the classic crankshaft mechanism, which is still the most commonly used internal combustion engine mechanism. In this paper, the crankshaft mechanism with a negative pivot point has been elaborated in detail. The given calculations show that the aim of the crankshaft mechanism can be achieved, in other words, it is possible to obtain a prolonged expansion time compared with compression time and thus open the possibility of constructing a two-stroke high-speed engine. From the diagrams depicting a comparison of this crankshaft mechanism with a classical crankshaft mechanism, it can be seen that it is possible to design a mechanism that will give an increased expansion time compared with compression time. Based on the acceleration diagram it is expected that after the load distribution on the crankshafts has been applied, the stresses will be approximately twice as high as the classical mechanism. This new and innovative crankshaft mechanism gives the ability to increase engine efficiency, ultimately resulting in lower fuel consumption. In addition to increased efficiency, due to double paired crankshaft. It is expected that the mechanism produces less vibration compared to the conventional crankshaft mechanism.