Gear Change Research Articles

ОЦІНЮВАННЯ СТІЙКОСТІ РОБОТИ АВТОМОБІЛЬНОГО ДВИГУНА ЗА УМОВИ ПОСТІЙНОЇ КУТОВОЇ ШВИДКОСТІ КОЛІНЧАСТОГО ВАЛА

The operation of the automobile engine at a constant angular speed of the crankshaft at an unsteady mode of movement of the car allows increasing its energy and fuel efficiency. It is necessary to use a continuously variable transmission, which allows you to change the speed of the vehicle with infinitely variable gear ratio change transmission without acceleration of the rotating masses of the engine. With a continuously variable automatic change gear ratio of the transmission, it is possible to realize engine operating modes that provide maximum effective engine power, maximum effective engine torque, and also minimum effective specific fuel consumption. It should be noted, that even with perfect management continuously variable transmission fails to obtain the constant value of the angular velocity of the crankshaft, as the internal combustion engine generates oscillations of the indicator torque. As a result of the study, an assessment of the possibility of maintaining a constant angular velocity of the crankshaft at steady and unsteady vehicle motion modes was made. The possibility of transmission operation in the pre-resonance and non-resonance frequency regions has been taken into account. A method has been developed for assessing the stability of an automobile engine with uneven effective torque of an internal combustion engine and a continuously variable transmission. The calculated dependencies are obtained, taking into account the elastic-inertial properties of the transmission and the coefficient of unevenness of the engine's torque, allowing determining the maximum deviations of the angular velocity of the crankshaft in the considered vehicle motion modes. It is shown, that the operation of the transmission in the near- resonance zone not only leads to additional cyclic loads on the parts and components of the transmission itself, but also reduces the energy efficiency of the vehicle power plant. Recommendations to improve the performance of motor-transmission units are formulated.

Bycatch mitigation of protected and threatened species in tuna purse seine and longline fisheries

Bycatch and mortality in fishing gear poses a conservation threat worldwide to many marine species. Resource managers and conservation scientists face challenges in identifying bycatch mitigation solutions that work for multiple taxa while maintaining acceptable levels of target fish catch. The most successful mitigation measures to address bycatch concerns are those that (1) minimize bycatch with limited or no impact on target species catch, (2) have been proven through at-sea experimental research, (3) are practical, affordable, and easy to use, and (4) do not risk the safety of the fishing vessel crew or the bycaught animals. We conducted a review of mitigation measures in fishing gears that target tuna and tuna-like species and that either prevent capture of non-target species in fishing gear or facilitate alive post-capture release, and evaluated these against 4 defined criteria: effective, proven, practical, and safe. This paper outlines the most effective bycatch mitigation measures, as based upon the best scientific information available, in commercial and artisanal pelagic longline and purse seine fisheries, specifically those that target tuna and tuna-like species. This review includes information on gear and operational changes to fishing practices that reduce bycatch for protected and threatened species across taxonomic groups, with a focus on cetaceans, sea turtles, seabirds, sharks, and istiophorid billfishes. The information provided can guide future research and management efforts in Regional Fisheries Management Organizations that are specific to tuna fishing and that aim to minimize impacts to protected and threatened species while maintaining viable commercial fisheries.

A Comparison of Optimal Gear Shifts for Stiff and Flexible Driveshafts During Accelerations

Reducing the fuel consumption is important and much development work is on engine optimization for best stationary fuel consumption. Here, a solution is developed for the transient operation to get fuel optimal accelerations, considering the actuation of fuel injection, wastegate control and gear utilization. The transient acceleration scenario studied is; a truck is approaching a red light at slow rolling speed, the light turns green and the truck shall be accelerated to 50 km/h with minimum fuel. Optimal control is used to find the fuel optimal control strategies. By using a dynamic engine model, taking the turbocharger dynamics into consideration, the engine air fuel ratio is taken into account. The differences and similarities between a stiff and flexible driveline model, are analyzed. The results show that the most dominating effect is the turbocharger dynamics of the engine. The two drivelines have similar gear changing strategies while the finer details differ due to the additional degrees of freedom that are present in the flexible driveline.

Optimal coordinating gearshift control of a two-speed transmission for battery electric vehicles

Abstract With the sustained technology advancement in the power battery, battery electric vehicles (BEVs) are considered as the most advisable alternatives of their internal combustion engine (ICE) counterparts. Research reveals that the implementation of multispeed transmissions for BEVs can reduce the vehicle energy consumption, improve the vehicle dynamic performance and downsize the battery package and the driving motor volume. Considering the potential advantages of multispeed transmissions equipped BEVs, this paper presents an investigation into the optimal coordinating gearshift control of a seamless two-speed transmission for BEVs. Firstly, to achieve the gearshift transient behaviour, the mathematical model of the powertrain system is established. Next, model-based gearshift tactics are proposed for the torque phase and the inertia phase respectively. Subsequently, the proposed control tactics based optimal controllers are developed to achieve high-quality gearshift in the whole gear shifting process. To be more specific, in the torque phase, the controller aims at optimising dual objectives together, namely the vehicle jerk and friction work, and the control objective of the inertia phase only focuses on decreasing the friction work due to the coordinating gear shifting tactic. Finally, based on available sensor signals, sliding mode observers are employed to estimate unmeasurable torque as feedback information for the optimal controllers in different gear states. Simulation results demonstrate that the devised control approaches can promote gear change performance comprehensively.

Effects of fishing practice changes on pelagic shark longline captures in the Gulf of Gabes, Tunisia

Abstract In order to increase their catches, longliners targeting sharks in the Gulf of Gabes, Tunisia, have increased the number of hooks per basket and have included new bait types instead of mackerel (Scomber scombrus). This paper reports the effects of these changes on catch composition, catch rates, size distribution, life‐stage captures, and mortality at haulback. Data from 48 and 96 longline sets, carried out during the shark fishing seasons of 2007 and 2008, with two hooks per basket, and 2016 and 2017, with five hooks per basket, respectively, were examined to assess the effect of gear change. Moreover, the effects of bait types were inspected based on 33 fishing sets using whole mackerel, 19 using salema (Sarpa salpa) halves, and 27 using pieces of stingray (Dasyatis spp.), sampled during 2016 and 2017. The species composition indicated that longliners expand the vertical distribution of their hooks to operate from the surface to the bottom. The catches with both longline designs were dominated by sandbar shark (Carcharhinus plumbeus). Despite gear changes, the catch rate of C. plumbeus decreased by 42.21%, suggesting population decline. The size composition indicated a shift towards larger specimens, mainly adult females, which could jeopardize the shark population. Moreover, the mortality of the main species at haulback seems to be affected by the design of the longline. The bait used, mainly pieces of stingray, significantly increased the catch rate of sandbar shark, which suggests a greater attractiveness of the new bait; however, fish size and mortality rates at haulback were unchanged in response to bait variation. The fishery operates in shark nursery grounds, which exposes these fish (principally C. plumbeus) to considerable exploitation pressure. The new fishing practices intensified the pressure and thus the risk of a rapid depletion of populations. To preserve the shark species in the area, the use of new gear and attractive bait should be banned.

Исследование влияния строительного дифферента малых промысловых судов с большой полнотой корпуса на мореходные качества

The paper highlights the problem of the small trawlers with great block coefficient, despite their optimal architectural and constructive characteristics for fishing in the Baltic Sea. it has been stated that when the expected speeds of the vessel are reached, their towing resistance increases greatly and a significant trim appears on the bow. To clarify the reasons there have been carried out the additional studies of the relation between changes in the landing gear and the towing resistance of the vessel in different modes of movement in order to select the optimum trim for the vessel. The test program included towing tests of a ship model in the speed range 4-12 knots 
 of a full-scale ship with one displacement value and different initial trim values at the stern. It has been inferred that at the stage of designing small fishing vessels (up to 24 meters long) it is advisa-ble to limit the maximum speed to 11 knots, which corresponds to a Froude number ≈ 0.4. Further increase in the speed of the vessel will result in rising a residual resistance coefficient considerably, which will lead to a disproportionate increase in the required power. The residual resistance coeffi-cient of the hull is minimal, provided that the vessel moves at the calculated speed with an even keel, while the optimum angle of the initial trim makes 1.0-2.5 degrees aft. Improper longitudinal balance of small fishing vessels with a large completeness of contours can lead to an increase in re-sidual resistance of up to 30%. The experimental results can be applied to all small fishing vessels with similar block coefficients. It has been recommended to conduct the full-scale tests with differ-ent ship models having various block coefficients in order to define the dependence between the completeness of the vessel and the value of drawdown.

Measurement Based Validation of an Electro-Pneumatic Gearbox Actuator

The objective of the research is to analyze the behavior of the developed electro-pneumatic actuator model and compare it to the behavior of the real system. The actuator achieves the requested gear changes by moving the two pistons inside the cylinder and it is operated by three-way two-position solenoid valves. Since not all model parameters are exactly known, such as contraction coefficients and friction parameters, they can be estimated based on literature then they can be further tuned to minimize the error of the simulation. The developed nonlinear model is capable of describing the dynamic behavior of the gearbox actuator, thus it can be used to analyze the effects of constructional modifications and it can serve as Model in the Loop (MIL) environment for controller testing.

Fishery Improvement Projects as a governance tool for fisheries sustainability: A global comparative analysis.

Fishery Improvement Projects (FIPs) are a form of private governance using seafood supply chains to reduce environmental impacts of fishing in some of the most challenged fisheries. Some FIPs are industry-led, others are championed by NGOs. They range across many different fishery types, in both high- and low-income settings. Their diversity is notable, and their proliferation remarkable. This rapid growth suggests FIPs are becoming a key feature of the fisheries governance landscape globally. Based on a global sample of 107 FIPs, we systematically examined their reported actions, the actors involved, and their achievements in terms of policy and practice outputs. The most common actions were dialogues with policy stakeholders, data collection, and educational efforts directed at fishers. Common policy outputs included development of management plans and/or a management body, and rules for limiting entry and increasing compliance. Practice related outputs were dominated by gear changes, and observer and traceability programs. Only crab and lobster FIPs engaged in sustained policy conversations as one of the most common actions. Shrimp and tuna fisheries report more engagement in testing and implementing changes to fishery practices. While supply chain actors are involved in all FIPs, retailers and 1st tier suppliers are relatively absent from FIP activities, and are primarily involved in rallying financial support or some policy engagement. Based on our analysis we discuss the opportunities and challenges FIPs will likely need to engage with to contribute to a global transition to more socially and environmentally sustainable fisheries. We outline key areas where further work is needed to understand how FIPs can improve their contribution to global fisheries governance in the future.

A seascape-scale habitat model to support management of fishing impacts on benthic ecosystems

Minimizing fishing impacts on seafloor ecosystems is a growing focus of ocean management; however, few quantitative tools exist to guide seascape-scale habitat management. To meet these needs, we developed a model to assess benthic ecosystem impacts from fishing gear contact. The habitat impacts model is cast in discrete time and can accommodate overlapping fisheries as well as incorporate gear-specific contact dynamics. We implemented the model in the North Pacific using fishing data from 2003 to 2017, estimating that habitat in 3.1% of the 1.2 million km2study area was disturbed at the end of the simulation period. A marked decline in habitat disturbance was evident since 2010, attributable to a single regulatory gear change that lifted trawl gear components off the seafloor. Running scenarios without these gear modifications showed these policies might have contributed to a 24% reduction in habitat disturbance since their implementation. Ultimately, model outputs provide direct estimates of the spatial and temporal trends of habitat effects from fishing — a key component of regulatory policies for many of the world’s fisheries.

Research of the gear changing process for a medium-tonnage cargo vehicle

One of the promising innovation vectors in the automotive industry is the automation of mechanical manual transmissions, which allows starting, maneuvering and changing gears in an automatic operation mode of the power unit, which ensures a reduction in the total time of the switching process, as well as enhances dynamic qualities and fuel economy of the vehicle. This article deals with the approach of scientists of Nizhny Novgorod State Technical University in the implementation of the project to automate the process of shifting gears of a GAZ medium-tonnage truck.

Examining Life History Shifts and Genetic Composition in a Hatchery Steelhead Population, with Implications for Fishery and Ocean Selection

AbstractSteelhead Oncorhynchus mykiss exhibit significant variation in life histories. Dworshak National Fish Hatchery (NFH)‐stock steelhead exhibit a life history that is unique compared to other Columbia River basin hatchery summer steelhead stocks, as it is dominated by older and larger‐length fish relative to conspecifics. We evaluated changes within the Dworshak NFH stock's ocean age composition and length at age from run years 1978 to 2016 using samples collected from the commercial gill‐net fishery, the sport fishery, and the hatchery trap. In addition, we analyzed the genetic composition of the stock by comparing samples collected in 1969 from the wild founding stock to samples from recent returns. We found that Dworshak NFH steelhead became younger across the study, with fewer of the oldest, three‐ocean fish (i.e., rearing in the ocean for 3 years) and increases in the proportion of the population returning as one‐ocean fish (i.e., rearing in the ocean for 1 year). Length at ocean age decreased for all ocean ages; however, the decrease was not significant in one‐ocean fish. In general, samples collected from gill nets and the sport fishery contained fish with older ocean ages and larger sizes at age compared to samples collected from the hatchery trap. Neutral genetic diversity, as measured from a panel of single‐nucleotide polymorphic markers, showed no changes between the sample of fish representing the original founders and the present‐day population. Life history shifts observed in Dworshak NFH‐stock steelhead were likely influenced by a variety of factors, including gear selectivity and changing ocean conditions. Decreases in ocean age composition and length at age have implications for both fishery and broodstock management as well as generating concern that similar trends may be occurring within wild steelhead stocks.

Energy optimization of logistics transport vehicle driven by fuel cell hybrid power system

To reduce the transportation cost of logistics industry and realize the cleanliness and environmental protection of transportation process, the energy management of logistics transportation vehicles driven by proton exchange membrane fuel cell/Li-ion hybrid power system was studied. Based on the high repeatability of vehicle routing, an energy management strategy is proposed to optimize hydrogen consumption on the premise of ensuring the stability of operation process. To improve the proton exchange membrane fuel cell output characteristics, the maximum power point tracking method based on conductance increment is used, and then the maximum power point, which is seared at the first time, is corrected again by simulated annealing algorithm. The power output control system of Li-ion battery pack based on dynamic programming is also designed. The state variables, control variables, constraint functions, objective functions and cost functions of the drive system are designed according to the related parameters such as vehicle gear change, demand torque and state-of-charge of Li-ion battery pack. The principle of equivalent hydrogen consumption is used to measure the energy output of Li-ion battery, and the fuzzy logic controller is used to simplify the expression of system state and control variables. Finally, the optimal output power sequence of Li-ion battery is calculated. And the experimental results show that after dynamic programming optimization, the driving system can ensure the stable operation of logistics vehicles and greatly reduce the consumption of hydrogen. These results can provide reference for energy management of other types of vehicles driven by proton exchange membrane fuel cell hybrid power system.

THE USAGE OF BOARD COMPUTERS IN TRACTORS

The work objective was identification of present state and trends of board computer usage in tractors available in Polish and European market. Automation of construction machines is widely used in land management to improve the accuracy of the marking works during geodetic control. Investigation have included: automatic control of unit monitoring – before and after starting up engine, electronic system of automatic, damage engine switching off; fuel dosage control (engine rotary speed), radar sensor, ventilation; gear box – gear change, gear programming, damage diagnosis; lever – electronic steering system, damage diagnosis, steering keys outside cab. To basic tractor units equipped with electronic steering belong: engine, gear box, lever, live axle, power take off, radar, air-conditioner, planning.

Internal Combustion Engines Forces

The paper presents an algorithm for determining the dynamic parameters of the internal combustion mechanism. Shows the force distribution (on the main engine mechanism) on internal combustion engines. Dynamically, tools can be distributed in the same way as forces. Practically, in dynamic regimes, speeds have the same synchronization with forces. The method applies separately for two distinct situations: When the engine is operating with a compressor and the engine system. For the two individual cases, two independent formulas for dynamic kinematic forces (gearbox) are obtained. Calculations are made for a single cylinder engine. Dynamic gear change resembles a variation in engine angular speed. It is more difficult to consider (theoretically) the effect on a multi-cylinder engine.

Automatic Discovery of Railway Train Driving Modes Using Unsupervised Deep Learning

Driving modes play vital roles in understanding the stochastic nature of a railway system and can support studies of automatic driving and capacity utilization optimization. Integrated trajectory data containing information such as GPS trajectories and gear changes can be good proxies in the study of driving modes. However, in the absence of labeled data, discovering driving modes is challenging. In this paper, instead of classical models (railway-specified feature extraction and classical clustering), we used five deep unsupervised learning models to overcome this difficulty. In these models, adversarial autoencoders and stacked autoencoders are used as feature extractors, along with generative adversarial network-based and Kullback–Leibler (KL) divergence-based networks as clustering models. An experiment based on real and artificial datasets showed the following: (i) The proposed deep learning models outperform the classical models by 27.64% on average. (ii) Integrated trajectory data can improve the accuracy of unsupervised learning by approximately 13.78%. (iii) The different performance rankings of models based on indices with labeled data and indices without labeled data demonstrate the insufficiency of people’s understanding of the existing modes. This study also analyzes the relationship between the discovered modes and railway carrying capacity.

Gait profile score identifies changes in gait kinematics in nonfaller, faller and recurrent faller older adults women

BackgroundQuantification of differences in gait kinematics between young and older adults provides insight on age-related gait changes and can contribute to the investigation of risk of falls. Gait Profile Score (GPS) is an index that indicates gait quality, using kinematic gait data, but so far it has not been used in an elderly population without neurological conditions. Research questionIs the Gait Profile Score (GPS) an index that shows reliability for use in old adults? Does this index detect changes in gait quality observed by kinematic data between nonfaller, faller and recurrent faller older adults? MethodsForty-nine women (mean age 72,43 ± 6,44; 27 faller and 22 nonfaller) were included in the study. Intra-session reliability was obtained from the intraclass correlation coefficient (ICC) between the five strides of each session. ResultsOverall value of GPS shows no difference between nonfaller (6.65 ± 1.59º), faller (6.67 ± 2.05º) and recurrent faller (6.62 ± 0.86º) older adult. In all groups larger values of Gait Variable Scores (GVS) were observed in the hip and knee joints. Intra-session ICC values the GVS and GPS presented high stability, ranging from 0.80 to 0.99. MDC lower values in GPS were observed in the faller (0.39; ICC - 0.97) and recurrent faller (0.69; ICC – 0.90). SignificanceDue to the high reliability, GPS has proven to be a valid method to analyze the gait quality of faller and nonfaller older woman. The most sensitive indexes (GPS and GVS) are the gear changes in fallers and recurrent fallers.

Onychomycosis in Athletes.

Onychomycosis is a common disorder that is difficult to cure. Prevalence is lower in children (0.7%), but athletes are 2.5-fold more likely to develop the disease, with infections of the toenails seven times more prevalent than those of the fingernails. This is a concern for athletes as it can interfere with their performance. The risk of developing onychomycosis is increased by the warm environment of many sports activities; the use of occlusive footwear; the warm, moist environment associated with socks and sweating; shared, close quarters among athletes; and trauma to the foot and toenail. Once infected, onychomycosis treatment requires a long duration of treatment with strict compliance, a potential problem for younger patients. Treatment carries the risk of significant side effects, and recurrence rates remain high. Avoiding infection can be a potent first line of defense and may circumvent the need for treatment. Preventive recommendations such as keeping toenails short and proper washing of laundry, to name a few, can be effective and are discussed here. Technological improvements such as synthetic, moisture-wicking socks and well-ventilated, mesh shoes have also been shown to reduce moisture and injury. Education about preventing fungal spread and improving hygiene in the locker room, gym, and pool are of critical importance. This overview of onychomycosis focuses primarily on the preventive measures and innovative changes in athletic gear. It also provides a compact step-by-step guide to prevention intended to be useful for both the general public and the professional. It can be reproduced to use as a handout for athletes, trainers, and coaches.

Investigation on the influence of work holding equipment errors on contact characteristics of face-hobbed hypoid gear

This paper proposed the accurate mathematical model considering work holding equipment errors based on the three-face cutter differing from typical commercial software. The simulated flow included manufacturing issues from industry applications have been established. Quasi-static loaded tooth contact analysis was used to discuss the contact characteristic and gear geometry with existence of radial and angular eccentric errors. In addition, the correspondence between transmission error and gear geometry was established. The method of separating the long wave (low frequency) and short wave (high frequency) from total transmission error has been proposed. Results show that the effect of angular eccentric error on gear geometry is more sensitive than that of radial eccentric error. The gear geometry deviations present periodic changes because of variation of pitch error. And radial eccentric error cannot influence the position and shape of contact pattern. On the contrary, with existence of angular eccentric error, the contact area moves to the heel side and then backward. Furthermore, the length of contact pattern is firstly decreased and then increased in one period. The transmission error is sensitivity for both two eccentric errors and the peak to peak value of transmission error increase obviously.

Analysis of dynamic characteristics of power split spiral bevel gear transmission system based on teeth geometric contact analysis

To solve the dynamic load distribution mechanism of the power split transmission system of spiral bevel gears, according to the characteristics of the closed loop of power flow, the deformation coordination condition is deduced. Through the gear teeth geometric contact analysis technique, the time-varying meshing stiffness conditions in the model are solved. The linear time-varying dynamic model of the torsional vibration of the bevel gear split transmission system is established by the lumped mass parameter method. Considering the influence of time-varying mesh stiffness excitation conditions and damping, the dynamic differential equations are treated in a dimensionless way. The dynamic load change and dynamic response characteristics of the system are obtained by numerical solution, and the influence of parameters such as speed and damping on dynamic power flow and dynamic characteristics of the system is revealed. The results show that with an increase of meshing damping ratio, dynamic power flow of each gear pair changes little, and the vibration acceleration and its root mean square value of each gear pair of the system are smaller. With an increase in speed, vibration acceleration and its average amplitude increase.

Research on static load sharing characteristics of power split two-stage five-branching star gearing drive system

Power split two-stage five-branching star gearing drive system has been widely used in the aviation engine reducer and the helicopter’s main reducer. For the problem of load sharing characteristics of this system, a static load-sharing calculation model is established. According to the power flow closed loop characteristics of the whole system, the torque equilibrium condition and deformation compatibility condition of the system are established. The load sharing coefficient of the star gears and the system is calculated by using the principle of the integrated equivalent mesh error and the static equilibrium condition of the floating element. Further, the influence of manufacturing error, installation error and floating on load sharing coefficient is analyzed. When the load sharing characteristic is independently influenced by the error, the load sharing coefficient of each star gear changes periodically with time. Basic component floating can significantly improve the load sharing performance. The correctness of the theoretical algorithm is verified by experiments. A new algorithm is proposed for engineering application.