An Energy Management Strategy and Parameter Optimization of Fuel Cell Electric Vehicles

This study involved a detailed analysis of an energy distribution strategy and the parameters of key components of fuel cell electric vehicles (FCEVs). In order to better utilize the advantages of multiple energy sources, the wavelet-fuzzy energy management method was used to adjust the demand power allocation among multiple energy sources, and particle swarm optimization (PSO) was used to solve highly nonlinear optimization problems under multi-dimensional and multi-condition constraints. The multi-objective optimization problem of predefined driving cycle powertrain parameters about fuel economy and system durability was studied. The parameters of the key components of the system were optimized, including the size parameters of the air com-pressor and the number of batteries and ultra-capacitors. Furthermore, the driving state under specific working conditions was analyzed, and a nonlinear model with system durability and fuel economy as the optimization objectives were established, which greatly reduced the costs, reduced the fuel consumption rate and extended the battery life. The simulation results showed that for a UDDS cycle, the FCS’s maximal net output power of 83 kW was optimal for the fuel economy and system durability of a fuel cell city bus.

A Study on a New Independent Metering Valve for Hydraulic Boom Excavator

Nowadays, hydraulic excavators are an indispensable part of the construction industry; however, conventional hydraulic excavators consume a great deal of fossil fuel and release a large amount of pollution emissions into the environment. This causes many unwanted costs, therefore, effective solutions are required to solve the above-mentioned problems. In this paper, a new independent metering system is proposed to improve energy-saving and reduce costs of a conventional system. In detail, a directional valve is used to control movement and three electro-hydraulic poppet valves are integrated to adjust the flow rate at the inlet and outlet ports of the boom cylinder. In addition, a control strategy based on the coordination between the speed of the pump and the opening area of the spool valve is designed to improve the performance of the system. Specifically, the valves are controlled based on the strategy that the meter-in valve is opened fully to reduce throttling losses and that the meter-out valve is controlled to reduce leakage. The speed of the pump is adjusted according to the feedback position signal. To demonstrate the effectiveness of the new configuration, a real test bench of the boom system was built under laboratory conditions. From the experimental results, the new independent metering valve system not only works with a high tracking precision, but it also reduces energy consumption. Compared with a conventional independent metering system, the fuel economy of the proposed structure can achieve a reduction of approximately 6.5%.

Investigation of the Contribution of Deceleration Fuel Cut-off and Start/Stop Technologies to Fuel Economy by Considering New European Driving Cycle

Greenhouse gas (GHG) emissions released into the atmosphere cause climate change and air pollution. One of the main causes of GHG emissions is the transportation sector. The use of fossil fuels in internal combustion engine vehicles leads to the release of these harmful gases. For this reason, since 1992, several standards have been introduced to limit emissions from vehicles. Technologies such as reducing engine sizes, advanced compression-ignition or start/stop, and fuel cut-off have been developed to reduce fuel consumption and emissions. In this study, the contribution of deceleration fuel cut-off and start/stop technologies to fuel economy has been examined considering the New European Driving Cycle. Therefore, the fuel consumption values were calculated by creating a longitudinal vehicle model for a light commercial vehicle with a diesel engine. At the end of the study, by using the two strategies together, fuel economies of 17.5% in the urban driving cycle, 3.7% in the extra-urban cycle, and 10% in total were achieved. CO2 emissions decreased in parallel with fuel consumption, by 10.1% in total.

Comparative Life-Cycle Assessment of Liquefied Natural Gas and Diesel Tractor-Trailer in China

Many countries, especially China, have extensively promoted liquefied natural gas (LNG) to replace diesel in heavy-duty vehicles for to achieve sustainable transport aims, including carbon peaks and neutrality. We developed a life-cycle calculation model for environmental load differences covering vehicle and fuel cycles to comprehensively compare the LNG tractor-trailer and its diesel counterpart in China on a full suite of environmental impacts. We found that the LNG tractor-trailer consumes less aluminum but more iron and energy; emits less nitrogen oxide, sulfur oxide, nonmethane volatile organic compounds, and particulate matter but more greenhouse gases (GHG) and carbon monoxide (CO); and causes less abiotic depletion potential, acidification potential, and human toxicity potential impacts but more global warming potential (GWP) and photooxidant creation potential (POCP) impacts. Poor fuel economy was found to largely drive the higher life-cycle GHG and CO emissions and GWP and POCP impacts of the LNG tractor-trailer. Switching to the LNG tractor-trailer could reduce carbon dioxide by 52.73%, GWP impact by 44.60% and POCP impact by 49.23% if it attains parity fuel economy with its diesel counterpart. Policymakers should modify the regulations on fuel tax and vehicle access, which discourage improvement in LNG engine efficiency and adopt incentive polices to develop the technologies.

The curious saga of dehydrogenation/hydrogenation for chemical hydrogen storage: A mechanistic Perspective

Hydrogen Storage is an indispensable component of hydrogen based fuel economy. Chemical hydrogen storage relies on development of lightweight compounds which can deliver high weight percentage of H2 at moderate...

Joining Techniques Like Welding in Lightweight Material Structures

In order to take more stringent measures in fuel economy and achieve the determined performance targets, the automotive industry needs to reduce the weight of the vehicles it produces. For this reason, all automobile manufacturers have determined their own strategies. Some manufacturers use lighter aluminum, magnesium, and composite components in their cars. In this study, the joining techniques of lightweight materials such as welding and the processes of their industrial use have been examined. There is currently no single technology that can combine all metallic panels in a car body structure. However, it is known that various joining technologies are used together. With the potential to combine certain combinations of steel and aluminum, manufacturers and scientists continue to work to identify technologies with the highest potential for lightweight joining and put them into use in high-volume automobile production. Therefore, it is important to examine the weldability of light materials such as magnesium, titanium, and aluminum.

Methodology for determining the flow rate and temperature of generated hot water when calculating the thermal diagram of a hot water boiler room

The consumption and temperature of hot water produced by boiler units are calculated using such a quantity as the consumption of the consumed network water. The formulas represent functional dependencies connecting the obtained values not only with the consumption of heating water, but also with the consumption of hot water supplied for recirculation, for own needs and for the needs of the fuel economy. They take into account the losses of network and hot water. The formulas are obtained as a result of the joint solution of the equation for the total consumption of hot water and the equation for its partial costs.