Abstract
The hydromechanical transmission IC2OC operates as an Input Coupled transmission at low speeds and as an Output Coupled transmission at high speeds; a series of clutches allows the shift ...between two layouts. In this way the transmission speed range can be almost doubled.
The design of this transmission requires the full mechanical speed value for both basic layouts. Since these values heavily influence transmission performance, their choice must be made carefully.
In this paper two choice criteria for these two speeds are proposed and discussed: the first one refers to the optimal choice for each basic layout; the second sets these speeds in correspondence with the speed of the maximum energy processed in a working cycle.
The effectiveness of these two criteria, applied to an off-road vehicle transmission, demonstrates that the former guarantees greater efficiency than the latter, despite its good assumptions.
Erosion by wind is one of the principal processes associated with land degradation in drylands and is a significant concern to land managers and policymakers globally. In the drylands of North ...America, millions of tons of soil are lost to wind erosion annually. Of the 60 million ha in the United States identified as most vulnerable to wind erosion (arid and dominated by fine sandy soils), 64% are managed by federal agencies (37 million ha). Here we review the drivers and consequences of wind erosion and dust emissions on drylands in the United States, with an emphasis on actionable responses available to policymakers and practitioners. We find that while dryland soils are often relatively stable when intact, disturbances including fire, domestic livestock grazing, and off‐highway vehicles can increase horizontal eolian flux by an order of magnitude, in some cases as much as 40‐fold. A growing body of literature documents the large‐scale impacts of deposited dust changing the albedo of mountain snow cover and in some cases reducing regional water supplies by ~5%. Predicted future increases in aridity and extreme weather events, including drought, will likely increase wind erosion and consequent dust generation. Under a drier and more variable future climate, new and existing soil‐ and vegetation‐disturbing practices may interact in synergistic ways, with dire consequences for environments and society that are unforeseen to many but fairly predictable given current scientific understanding. Conventional restoration and reclamation approaches, which often entail surface disturbance and rely on adequate moisture to prevent erosion, also carry considerable erosion risk especially under drought conditions. Innovative approaches to dryland restoration that minimize surface disturbance may accomplish restoration or reclamation goals while limiting wind erosion risk. Finally, multidisciplinary and multijurisdictional approaches and perspectives are necessary to understand the complex processes driving dust emissions and provide timely, context‐specific information for mitigating the drivers and impacts of wind erosion and dust.
This paper proposes methodologies to estimate the electric energy and power consumption by light-duty plug-in electric vehicles (PEVs). Using the travel patterns of light-duty vehicles in the U.S. ...obtained from the 2009 National Household Travel Survey, the PEVs' energy and power consumption are estimated for two uncontrolled charging scenarios.
This paper presents the results of analyses that were focused on pollutant emissions from road vehicles classified into the generalised categories with respect to vehicle use. The analyses were ...performed using the authorised results of Poland's pollutant emission inventory, carried out in 1990–2020 by the National Centre for Emissions Management (KOBiZE) at the Institute of Environmental Protection – National Research Institute (IOŚ-PIB) in order to meet requirements for the national emissions reporting under EU legislation and the UNECE Convention on Long-range Transboundary Air Pollution. The following road vehicle categories were analysed: passenger cars, light duty vehicles, heavy-duty trucks, buses (urban buses and coaches) and L category (motorcycles, mopeds, quads, microcars). The emissions of selected pollutants that are harmful to the health of living beings were studied, i.e. nitrogen oxides, non-methane volatile organic compounds, sulfur compounds, particulate matter size fractions, carbon monoxide and lead compounds. The shares of national annual pollutant emissions from each studied vehicle category of the total pollutant emissions from road transport were determined. With the aim to assess trends in improving environmental properties of road vehicles, there were determined changes of the energy emission factors for individual pollutants in all the vehicle categories under the study. The results obtained showed dynamic decreases in the energy emission factors for nitrogen oxides, non-methane volatile organic compounds and carbon monoxide. In the case of particulate matter emission, the improvement was not as pronounced. The evident reduction in the emissions of sulfur and lead compounds in the 21st century was confirmed to be a consequence of practical elimination of these compounds from road vehicle fuels.
Carbonyls play a vital role in atmospheric photochemistry. Vehicle emission is among most important primary emission sources of carbonyls in urban areas, yet knowledge is quite scarce about ...real-world emissions of carbonyls with the changing on-road vehicle fleets. In this study, emissions of carbonyls were characterized based on tests in a busy urban tunnel in south China. Emission factor (EF) of carbonyls was measured to be 9.89 ± 0.65 mg km−1 on average, in which formaldehyde alone shared 53.1% with an EF of 5.25 ± 0.35 mg km−1, followed by acetaldehyde with an EF of 1.47 ± 0.13 mg km−1. Glyoxal and methylglyoxal showed identical EFs of 0.18 ± 0.02 mg km−1. Multiple linear regression retrieved total carbonyl EFs of 5.68, 47.71 and 35.09 mg km−1 and ozone formation potentials (OFPs) of 38.4, 329.3, and 242.4 mg km−1 for gasoline, diesel and liquefied petroleum gas vehicles (LPGVs), respectively. The unexpectedly high carbonyl emissions from LPGVs were largely attributed to the lack of after-treatment systems or the inefficiency of the after-treatment systems. Among vehicle-emitted non-methane hydrocarbons and carbonyls, carbonyls could contribute ~20% of the total OFPs while they only accounted for 7.1% of the total mass.
Display omitted
•Real-world vehicular carbonyl emissions were tested in an urban tunnel.•Formaldehyde was the major species accounting for over half of carbonyl emissions.•EFs for each fuel type vehicles were obtained via multiple regession analysis.•Carbonyls could contributed ~20% of the total OFP by vehicular NMHCs and VOCs.•The OFP of carbonyls from LPGVs was about 5 times that from GVs on average.
This article presents solutions to challenges in using a low-density flash lidar for application to a heavy road vehicle Autonomous Emergency Braking (AEB) system. Low-density flash lidars are ...relatively new to the commercial market and are much less expensive compared to point-cloud lidars. However, due to their low angular resolution, it becomes challenging to use the information provided by them for applications such as the AEB. Specifically, the challenges in identifying relevant targets and determining target width are discussed in this article, and solutions to the same are presented. Later, an AEB algorithm is developed for a heavy commercial road vehicle for demonstrating the usefulness of the proposed solutions. The AEB system is experimentally evaluated using a brake Hardware-in-loop system along with IPG TruckMaker, and the results are presented.
The development of a new three-phase bipolar inductive power transfer system that provides power across the entire width of a roadway surface for automatic guided vehicles and people mover systems is ...described. A prototype system was constructed to verify the feasibility of the design for a number of moving loads (toy cars). Here, 40 A/phase is supplied at 38.4 kHz to a 13-m-long test track. Flat pickups are used on the underside of each vehicle to couple power from the track to the vehicle. Finite element modeling software was used to design the geometrical position of the track cables and to predict the power output. This design resulted in a considerably wider power delivery zone than possible using a single-phase track layout and has been experimentally verified. Mutual coupling effects between the various track phases require additional compensation to be added to ensure balanced three-phase currents.
Artificial potential fields and optimal controllers are two common methods for path planning of autonomous vehicles. An artificial potential field method is capable of assigning different potential ...functions to different types of obstacles and road structures and plans the path based on these potential functions. It does not, however, include the vehicle dynamics in the path-planning process. On the other hand, an optimal path-planning controller integrated with vehicle dynamics plans an optimal feasible path that guarantees vehicle stability in following the path. In this method, the obstacles and road boundaries are usually included in the optimal control problem as constraints and not with any arbitrary function. A model predictive path-planning controller is introduced in this paper such that its objective includes potential functions along with the vehicle dynamics terms. Therefore, the path-planning system is capable of treating different obstacles and road structures distinctly while planning the optimal path utilizing vehicle dynamics. The path-planning controller is modeled and simulated on a CarSim vehicle model for some complicated test scenarios. The results show that, with this path-planning controller, the vehicle avoids the obstacles and observes road regulations with appropriate vehicle dynamics. Moreover, since the obstacles and road regulations can be defined with different functions, the path-planning system plans paths corresponding to their importance and priorities.
This paper presents a novel closed-loop frequency control algorithm that captures the resonant frequency of a Wireless Power Transfer (WPT) system to obtain high-efficiency at maximum power transfer ...in moving electric vehicles. The control algorithm of the WPT system is designed regarding the WPT has magnetically coupled series-series resonant circuit topology. The study mainly focuses on catching the resonant frequency depending on the changes in air gap, load, and inductance. The proposed algorithm is able to detect the resonant frequencies, allowing the maximum power transfer under inductive, ohmic, or capacitive behaviour of the system. Simple, fast and cheap structure of the algorithm renders obtaining the resonant frequency in a wide frequency range. Moreover, once the resonant frequency of the inverter is obtained, switching loss is minimized by leveraging Zero Current Switching (ZCS). The numerical simulations of the control algorithm are performed in MATLAB/Simulink. Furthermore, a Finite Element Method (FEM) analysis is conducted by utilizing co-simulation of Ansys Maxwell 3D - Simplorer - MATLAB/Simulink. Finally, the developed system is experimentally tested for several air gap values and it is verified that the system is able to operate with high efficiency for the distances less than the critical air gap.
Tractor engine performance using hybrid biofuel (Soapnut oil methyl ester and pine oil blends)
Display omitted
•The hybrid biofuel strategy is adopted in a tractor diesel engine to eliminate the ...usage of diesel.•Highly viscous soapnut oil methyl ester is blended with low viscous pine oil.•The performance, combustion and emission characteristics were tested for the blended fuels.•BTE of the blend P50SNB50 and P75SNB25 were increased at full load condition compared with diesel.
Off-road vehicles used for construction and agricultural activities are one among the major source of exhaust emission. In order to reduce the environmental impact caused by these vehicles, it is encouraged to use biofuels which are renewable and locally available throughout the year. In the present work, a light biofuel- pine oil was introduced to blend with a methyl ester derived from soapnut oil. This paper details the experimental investigations of the performance, combustion and emission characteristics of an agricultural tractor engine using the combination of biofuels as a complete replacement of conventional diesel fuel. The methyl esters of soapnut oil was blended with pine oil at different proportions. The blends P100SNB0, P75SNB25, P50SNB50, P25SNB75 and P0SNB100 were prepared on volume basis and complied with ASTM D-6751 specifications. The experiments were conducted in a Simpson S217, Twin cylinder tractor diesel engine to study the performance, combustion and emission characteristics of the prepared biofuel. The results showed that the specific fuel consumption of P100SNB0 and biofuel blends decreases up to 4% with the increased engine load. The brake thermal efficiency of the blend P50SNB50 and P75SNB25 were increased by 8% and 10% respectively at full load condition compared with diesel. The biofuel blends outperformed conventional Petro-diesel in terms of smoke, unburnt hydrocarbon (HC) and carbon monoxide (CO) with a slight penalty on NOx emissions. Up to 50% pine oil blended biodiesel (P75SNB25, P50SNB50) fuel can be used in diesel engines without affecting its performance, emission and combustion characteristics.
PDF
