Wheel Power Research Articles

Effect of buoyancy force on buoyancy waterwheel efficiency using numerical flow simulation

In this work, the performance of a buoyant waterwheel to produce hydrokinetic power is investigated through analytical theory and computational fluid dynamics simulation. The impact of the buoyancy wheel is investigated by establishing the performance parameters through the use of a moving mesh approach and a realizable k-ε turbulence model. Transient simulation is required to comprehend the flow of physical processes. Using moving mesh as a transient methodology of the buoyancy waterwheel, numerical flow simulations and theoretical analytical methods are used in this study to assess the effect of buoyant force generated on the performance of the buoyancy wheel. The buoyancy waterwheel that will be put to the test has eight straight blades and a diameter of one meter. The pinwheel force and torque created in the numerical flow simulation (CFD) are 414.96 N and 207.48 Nm, respectively, whereas in the theoretical calculation they are 449.06 N and 224.53 Nm, according to the research findings. It is possible to compute the buoyancy wheel's power output and efficiency mathematically, yielding values of 1619.35 W and 68.07%. The buoyancy wheel's power output and efficiency, as determined by numerical flow simulation, are 1495.95 W and 62.88%, respectively. Based on theoretical and CFD study results, the buoyancy wheel generates a standard deviation of 7.62%. Thus, for the buoyancy wheel, a temporary method that makes advantage of the moving mesh characteristic is advised. This method can also be applied as a future alternative energy source for the Piko hydro turbine

DETERMINATION OF THE FUEL CONSUMPTION FOR A PASSENGER CAR THROUGH THE POWER AND SPEED ON IMITATION ROLLER STAND

Fuel consumption is one of the indicators that characterize the operational properties of road vehicles. In this study, the main factors that affect on fuel consumption of vehicles during its operation were analyzed. Most operating conditions can be repeated on the roller stand.
 The main mathematical methods that are used to calculate fuel consumption in road conditions and during bench tests were analyzed. It is indicated that for bench tests for fuel efficiency, it is important to correctly set and control the force on the vehicle wheels.
 The paper proposes a mathematical model for determining fuel consumption, which the amount of fuel consumption is calculated through the load power mode and vehicle speed. The calculation method is based on obtaining the efficiency of: indicator, mechanical, transmission and wheels, from which the overall vehicle efficiency was obtained. The table shows the results of calculating fuel consumption, wheel power and overall efficiency, as well as its constituent components. All parameters were defined for variable vehicle speed.
 A general algorithm and results of calculating fuel consumption in road conditions and on a roller stand with different power on wheels were given. The results of experimental studies were presented, where the fuel consumption was determined for cars of the VAZ brand. Fuel consumption increases in the range of 6 to 11 l/100 km if the wheel power varies in the range of 7 to 21 kW. This is in good agreement with the data calculated in the same range of parameters. Calculations show an increase in fuel consumption if the power is reduced from 5 kW and below. This can be explained by the fact that in this mode the vehicle moves in low gears of the gearbox. It was not possible to repeat this mode during the experiment.
 General conclusions and directions for further research were formulated.
 Key words: car, fuel consumption, a roller dynamometer, mode of load, mode of speed, efficiency.

Structure liming reduces draught requirement on clay soil

Liming with ‘structure lime’, comprising approximately 80–85% ground limestone and 15–20% slaked lime, has been promoted in subsidised environmental schemes in Sweden since 2010 to increase clay aggregate stability and mitigate particulate phosphorus losses to surface waters. To date, approximately 65,000 ha have been structure-limed. Apart from stabilising aggregates, liming may also improve other physical properties, such as soil strength. This study examined the effect of increasing application rate (0–16 t ha-1) of structure lime on soil strength, approximated by horizontal (draught requirement) and vertical (penetrometer resistance) measurements, in eight field soils (clay content 26–38%) to which structure lime had been applied two, three, four or six years previously. Draught requirement when cultivating with a multipurpose cultivator significantly decreased (by 11%) with the highest application rate of structure lime (16 t ha-1) compared with an unlimed control. This reduced the wheel power requirement by 7.1 kW and diesel consumption by 1.2–1.4 L ha-1, and lowered CO2 emissions by 3–4 kg ha-1. To clarify the general effect of structure liming, the mean value of all limed treatments was compared with that of the unlimed control. This showed that structure liming in general significantly reduced the draught requirement (by 7%). However, penetrometer resistance measurements revealed no significant effects of structure liming and no relation between draught requirement and penetrometer resistance measurements. Overall, the results indicate that structure liming can reduce fuel consumption, due to easier soil tillage, and thus lower CO2 emissions.

Comparative Assessment of Supervisory Control Algorithms for a Plug-In Hybrid Electric Vehicle

The study examines alternative on-board energy management system (EMS) supervisory control algorithms for plug-in hybrid electric vehicles. The optimum fuel consumption was sought between an equivalent consumption minimization strategy (ECMS) algorithm and a back-engineered commercial rule-based (RB) one, under different operating conditions. The RB algorithm was first validated with experimental data. A method to assess different algorithms under identical states of charge variations, vehicle distance travelled, and wheel power demand criteria is first demonstrated. Implementing this method to evaluate the two algorithms leads to fuel consumption corrections of up to 8%, compared to applying no correction. We argue that such a correction should always be used in relevant studies. Overall, results show that the ECMS algorithm leads to lower fuel consumption than the RB one in most driving conditions. The difference maximizes at low average speeds (<40 km/h), where the RB leads to more frequent low load engine operation. The two algorithms lead to fuel consumption differences of 3.4% over the WLTC, while the maximum difference of 24.2% was observed for a driving cycle with low average speed (18.4 km/h). Further to fuel consumption performance optimization, the ECMS algorithm also appears superior in terms of adaptability to different driving cycles.

Terrain mobility performance optimization: Fundamentals for autonomous vehicle applications. Part I. New mobility indices: Optimization and analysis

Based on an analysis of vehicle mobility performance indices in use, it is shown that an index for the optimization of autonomous vehicle mobility performance should be constituted as a set of technical parameters that result directly from the interactive dynamics of tires and terrain and should be measurable and controllable in real-time. In addition, the combination of the parameters should characterize the vehicle’s technical productivity/efficiency (not energy efficiency), and thus, enable the estimation and control of vehicle mobility performance. If such requirements are satisfied, the index can be optimized and optimization results can facilitate autonomous control design. This article provides results of a study to address the above-formulated requirements in the proposed mobility performance index.In Part I of this article, wheel mobility performance is characterized first by the wheel circumferential force and the actual linear velocity. The proposed wheel mobility performance (WMP) index mathematically relates the wheel circumferential force and velocity to the theoretical maximum performance. Thus, the actual performance can be evaluated in terms of the theoretical maximum performance in a similar manner that the actual energy efficiency is compared to its theoretical maximum, i.e., to unity. The WMP-index is then extended to multi-wheel vehicles. The proposed vehicle mobility performance (VMP) index relates the traction and velocity characteristics of all wheels to a theoretical maximum performance.Founded on the circumferential force and velocity characteristics of the wheels, the VMP-index mathematically reflects the influence of the power distribution among the wheels on the vehicle mobility performance. Hence, the VMP-optimization is formulated as an examination for the optimal tire slippages. Essentially, their combination characterizes the optimal wheel power split, and consequently, the best set of the wheel circumferential forces and the vehicle actual velocity for the maximum mobility performance in a given terrain condition. The tire slippages are subject to lower and upper bound constraints. The lower bound ensures positive tire slippages, and thus, positive traction of the wheels. The upper bound is imposed in the form of characteristic slippages such that exceeding them drives the wheels into an extremely nonlinear zone of the traction characteristic. In this zone, the wheel mobility margins drop significantly and some or all wheels can easily be immobilized. Further, the optimization is subject to the vehicle longitudinal dynamics, which sets the summation of the wheel circumferential forces equal to the motion resistance forces.By applying Lagrange Multipliers (LMs) to the objective function, a system of equations is arranged to compute the optimal tire slippages that correspond to the necessary conditions of an extremum of the objective function. The strict monotonicity property of the LM-based equations is then examined and the uniqueness of the solution is exhibited. Finally, the Hessian theory for a constrained optimal problem is used to prove that the solution is globally minimum.Part II discusses the computational results of mobility performance optimization for a 4x4 vehicle simulated on three homogeneous terrains and split terrains on flat surface and on slopes, with and without drawbar pull. Additionally, the vehicle with three conventional driveline systems is simulated in the same terrain conditions, and a detailed analysis establishes dependences between the optimal tire slippages and optimal circumferential forces of the wheels and their correlation to those provided by the driveline systems. Advantages of the mobility optimization for control design are explained and discussed. It is also concluded that the use of energy efficiency indices in mobility performance assessment can be considered as a supplementary, but not the primary subject-heading of the vehicle mobility performance.The mobility performance optimization directly contributes to mobility design that is illustrated by conceptual implementation of the optimization results in two driveline systems of the 4x4 vehicle: a driveline with positive engagement of the power-dividing units and a virtual driveline that serves for fully electric vehicles with in-wheel motors.Finally, a verification of the mobility optimization results and validation of the proposed mobility performance index is conducted through statistics-based assessment against experimental wheel circumferential forces and tire slippages.

Joint Component Sizing and Energy Management for Fuel Cell Hybrid Electric Trucks

This paper proposes a cost-effective way to design and operate fuel cell hybrid electric trucks (FCHETs) where a chance-constrained optimization is formulated. The aim of the introduced problem is to minimize a summation of component cost and operational cost with consideration of fuel cell (FC) degradation and cycle life of energy buffer. We propose to decompose the problem into two sub-problems that are solved by sequential convex programming. The delivered power satisfies a cumulative distribution function of the wheel power demand, while the truck can still traverse driving cycles with a similar speed and travel time without delivering unnecessarily high power. This allows to downsize powertrain components, including electric machine, FC and energy buffer. A case study considering different energy buffer technologies, including supercapacitor (SC), lithium-ion battery (LiB), and lithium-ion capacitor (LiC) is investigated in a set of trucking applications, i.e. urban delivery, regional delivery, construction, and long-haul. Results show that the power rating of the electric machine is drastically reduced when the delivered power is satisfied in a probabilistic sense. Moreover, the configuration with LiB as the energy buffer has the lowest expense but the truck with LiC can carry more payload.

On the issue of the wheel power radius with an elastic tire

Introduction (statement of the problem and relevance). Mathematical modeling of the car units, mechanisms and systems functioning strongly depends on the used calculation parameters values, for example, on the power radius of the wheel. Nowadays to research the power radius of a wheel with an elastic tire both the radius of the driving wheel and the dynamic radius are taken into account. The article is to consider which of the two is the power radius of a wheel with an elastic tire.The purpose of the study was to evaluate the influence of the chosen wheel power radius on the longitudinal characteristics mathematical modeling results of the tire adhesion with the supporting surface.Methodology and research methods. Methods of mathematical modeling and experimental studies were applied, followed by the comparative analysis of both the experimental and analytical data.Scientific novelty and results. The experimental dependences of the tire longitudinal adhesion coefficients on slippage have been obtained and compared using both the dynamic radius and the rolling radius as the power radius of the wheel in the driven mode.Practical significance. The mathematical descriptions parameters of the tire adhesion characteristics have been refined which allowed reducing the errors of the calculation results significantly.

Comparative field performance evaluation of different type of Pusa Electric Power Units

Pusa developed three walk-behind type electric power units were evaluated in 9.96 ha area for tillage in polyhouse,secondary tillage, planking and weeding-cum interculture operations at research farm of ICAR-IARI during kharif and rabi 2020 and 2021. The power of four-wheel and two-wheel electric power units was 350W while Pusa mini electric prime mover was having 450W power. The controlling-cum-guiding force for operation of four-wheel power unit, two- wheel power unit and mini electric prime mover was found 26.72, 30.9 and 22.7 N, respectively. Correspondingly, the draft force was 210, 245 and 300 N. Based on the rigorous field study, the effective field capacity with these electric power units were 2.3 times higher than manual operated four-wheel weeder for wide-row crops. The field efficiency with four-wheel, two-wheel electric power unit and mini electric prime mover was 78–83.26, 78.6–81.25 and 69.2–92.6% in weeding-cum-interculture operation, respectively. The walk-behind electric power units are also found to reduce operator’s drudgery by 80–85%. The mini electric prime mover was found 32.7% cheaper than the four-wheel and 17.2% than the two-wheel power unit. Its command area is one ha for secondary tillage and 5 ha for weeding-cum-interculture operations in wide-row crops.

Development of prediction methodology for CO2 emissions and fuel economy of light duty vehicle

Fuel economy prediction models usually require vehicle specifications such as a fuel consumption map which are not publicly available. Therefore, the present study proposed a new data analyzing procedure to predict CO2 emissions and fuel economy using on-road driving data without confidential specifications. Vehicle specifications such as gear ratios and vehicle mass which are provided in a service manual and driving data such as vehicle speed and CO2 emission were used to develop the prediction model. Instead of the fuel consumption map, linear equations for each gear between wheel power and CO2 emissions were used to predict CO2 emissions for various driving modes. Since higher gears exhaust less CO2 than lower gears (the seventh gear exhausted 24.4% less CO2 than the first gear), the accuracy of fuel economy prediction was improved by applying the equations for each gear stage. The accuracy of the prediction was verified by comparing it with measurement data. The comparisons showed that the equations for each gear can predict the fuel economy more accurately than one equation representing the entire gear. In worldwide harmonized light vehicles test cycle (WLTC) mode, the former had a maximum error of 6.1%, but the latter showed an error of 17.9%.

Energy-efficient torque-allocation strategy for a 6 × 6 vehicle using electric wheels

The utilization of multiple independently controlled electric wheels offers possibilities for enhancing not only the vehicle stability control but also energy efficiency of a vehicle. Previous research on energy-efficient torque allocation mainly focuses on four-wheel-independent-drive vehicles but not multi-axle all-wheel-drive vehicles. In this paper, we propose an energy-efficient torque-allocation strategy for a vehicle equipped with six identical electric wheels, using the Karush–Kuhn–Tucker (KKT) conditions to find candidates for globally optimal solutions. We present and compare the analytical forms of these candidates, including typical modes such as single-wheel-drive, two-wheel even-distribution, and three-wheel even-distribution modes. It shows that reallocating torques other than even distribution has energy-saving effects when the power loss characteristics of an electric wheel are not convex. For the studied electric wheel, the optimal mode revealed by KKT conditions is to progressively increase the number of active wheels with the torque demand. This method can be employed regardless of whether the power loss characteristics with respect to the torque demand are convex or nonconvex. The KKT conditions also allow the establishment of an online rule-based strategy to switch between different modes, depending on the vehicle speed and torque demand. Examples based on the electric wheel's power loss characteristics validate the effectiveness of the KKT-based allocation strategy. Compared with an even-distribution strategy, the electric wheels' energy losses and the vehicle's energy consumption can be reduced by 12.5% and 3.7%, respectively, over a complete driving cycle using the KKT-based strategy.

Kinematic and power characteristics of the elastic wheel while rolling with camber and convergence

Vehicles steering wheels are installed in such a way that the plane of the wheel makes a certain angle with vertical plane (so-called camber angle) and at the same time is located at an angle to machine movement direction (toe-slip angle). These angles result in lateral force, increased contact slip and increased wear on the wheel tread. In the article, from phenomena consideration occurring in the contact of an elastic wheel with a rigid base, kinematics and rolling mechanics issues of elastic wheels installed with camber and convergence are considered; dependences are derived that allow determining the wheel power and kinematic parameters, toe and camber angles optimal ratio from the point of view of reducing the wheel running track rolling resistance and wear is determined.

A Novel Energy-Efficiency Optimization Approach Based on Driving Patterns Styles and Experimental Tests for Electric Vehicles

This article proposes an energy-efficiency strategy based on the optimization of driving patterns for an electric vehicle (EV). The EV studied in this paper is a commercial vehicle only driven by a traction motor. The motor drives the front wheels indirectly through the differential drive. The electrical inverter model and the power-train efficiency are established by lookup tables determined by power tests in a dynamometric bank. The optimization problem is focused on maximizing energy-efficiency between the wheel power and battery pack, not only to maintain but also to improve its value by modifying the state of charge (SOC). The solution is found by means of a Particle Swarm Optimization (PSO) algorithm. The optimizer simulation results validate the increasing efficiency with the speed setpoint variations, and also show that the battery SOC is improved. The best results are obtained when the speed variation is between 5% and 6%.

MODELAREA ÎN MATLAB/SIMULINK A FUNCȚIONĂRII UNUI VEHICUL ELECTRIC ÎN DIFERITE CICLURI DE ACȚIONARE

Through this paper, we want to improve the methods of dynamic design of electric vehicles, by creating simulation models in Simulink. The models are represented by simulation schemes that consist of blocks of mathematical operators, interconnected based on mathematical calculation formulas. The initial input sizes, specified in Table 1, can be easily modified, giving the possibility to obtain several models for different design ideas. The results of the simulations are materialized in graphical diagrams and provide virtual time data on vehicle speed, acceleration, engine torque, wheel power, energy consumed, and distance traveled. In the first simulation scheme, the input variable shows a motor torque generator with values between 0-132 Nm. In the second simulation scheme, the input variable is speed, according to the ECE-15 urban cycle scenario.

Effect of Blends Gasoline with Oxygenated Additives in the Performance of Internal Combustion Engine

The objective of this study was to evaluate the effect of blends of different oxygenated additives on gasoline in SI engine Otto cycle. The formulations analyzed were: pure gasoline (type A), common gasoline (type C), gasoline type A + 15% (v/v) oxygenated additives (ethanol, ethyl octanoate, ethyl oleate). The experiments were performed using engine Branco 4-stroke and 2-cylinder, electric dynamometer, exhaust system, control unit composed of Multi-K unit, variable selector and load cell, stroboscope tachometer, fuel supply system and stopwatch. The rotation was conserved at 4400 rpm and wheel power varied from 3 kW to 12 kW, with intervals of 3 kW to obtain hourly consumption curves and brake specific fuel consumption. Even esters and ethanol having lower heat of combustion, hourly consumption was similar to pure gasoline (type A). In relation to the brake specific fuel consumption, increasing the wheel power had a better conversion of the mass of fuel burned into energy. Thus, this study showed that the mixture of gasoline and esters (ethyl octanoate and ethyl oleate) presented good efficiency in terms of consumption. This research contributes to the needs and to the current studies in which industries started to add renewable products to petroleum-derived fuels; in order to obtain more sustainable fuels at lower costs.

Про вплив форми меридіонального контуру на енергетичні характеристики відцентрового колеса компресора

This work is concerned with the development of approaches to the optimal aerodynamic design of centrifugal compressor wheels, which is due to the use of centrifugal stages in compressors of modern aircraft gas turbine engines and power plants. The aim of this work is a computational study of the effect of the meridional contour shape of a centrifugal compressor wheel on its power characteristics. The basic method is a numerical simulation of 3D turbulent gas flows in centrifugal wheels on the basis of the complete averaged Navier¬–Stokes equations and a two-parameter turbulence model. The computational study features: varying the shape of the hub and tip part of the meridional contour over a wide range, formulating quality criteria as the mean integral values of the wheel power characteristics over the operating range of the air flow rate through the wheel, and a systematic scan of the independent variable range at points that form a uniformly distributed sequence. As a result of multiparameter calculations, it was shown that in the case of a flow without separation in the blade channels of a wheel with a given starting shape of the meridional contour, varying that shape has an insignificant effect on the wheel power characteristics. It is pointed out that in similar cases it seems to be advisable to aerodynamically improve centrifugal wheels by varying the shape of their blades in the circumferential direction rather than in the meridional plane. This conclusion was made using rather a “coarse” computational grid, which, however, retains the sensitivity of the computed results to a variation in the centrifugal wheel geometry. On the whole, this work clarifies ways of further aerodynamic improvement of centrifugal compressor impellers in cases where the starting centrifugal wheel is a well-designed wheel with a flow without separation in the blade channels. The results obtained may be used in the aerodynamic optimization of centrifugal stages of aircraft gas turbine engines.

Study on testing vehicle’s driving wheel output power

This paper describes the principle, test methods and test procedures of vehicle wheel power based on the chassis dynamometer, as well as analyzes the test methods and factors that affected the test results of the driving wheel rolling resistance. At the same time, through the analysis of the test data of several groups of real vehicles, some attempts have been made to explore practical and feasible methods for automobile power performance test under the current conditions in our country. The relevant conclusions can provide a reference for improving the level of automobile power performance test.

Real drive cycles analysis by ordered power methodology applied to fuel consumption, CO2, NOx and PM emissions estimation

In this work three fuel consumption and exhaust emission models, ADVISOR, VT-MICRO and the European Environmental Agency Emission factors, have been used to obtain fuel consumption (FC) and exhaust emissions. These models have been used at micro-scale, using the two signal treatment methods presented. The manuscript presents: 1) a methodology to collect data in real urban driving cycles, 2) an estimation of FC and tailpipe emissions using some available models in literature, and 3) a novel analysis of the results based on delivered wheel power. The results include Fuel Consumption (FC), CO2, NOx and PM10 emissions, which are derived from the three simulators. In the first part of the paper we present a new procedure for incomplete drive cycle data treatment, which is necessary for real drive cycle acquisition in high density cities. Then the models are used to obtain second by second FC and exhaust emissions. Finally, a new methodology named Cycle Analysis by Ordered Power (CAbOP) is presented and used to compare the results. This method consists in the re-ordering of time dependant data, considering the wheel mechanical power domain instead of the standard time domain. This new strategy allows the 5 situations in drive cycles to be clearly visualized: hard breaking zone, slowdowns, idle or stop zone, sustained speed zone and acceleration zone. The complete methodology is applied in two real drive cycles surveyed in Barcelona (Spain) and the results are compared with a standardized WLTC urban cycle.

Epidemiological Analysis of Displaced Supracondylar Fractures.

Introduction: Supracondylar fractures are one of the most common fracture patterns sustained by children, and one of the most common injuries requiring operative fixation. Understanding the complications associated with supracondylar fractures is vital for the practicing orthopedic surgeon. This analysis of supracondylar fractures examined the clinically important aspects including vascular injury, compartment syndrome, neurological injury, brachialis entrapment, associated injuries, and etiologies of injury. Recent advances in technology have resulted in a myriad of new forms of recreational equipment for children to play with. The purpose of this study is to compare the historical literature, the current literature, and a single surgeon’s sample of supracondylar fractures. In addition, this study aims to evaluate if any changes in epidemiology or etiology have occurred due to the development of new recreational equipment.Objective: The purpose of this study is to evaluate and provide a qualitative overview of the epidemiology of displaced supracondylar fractures, to compare historically reported numbers to more recent literature as well as a single surgeon sample, and to evaluate if changes in epidemiology or etiology have occurred due to the new recreational equipment that children use.Methods: Some 75 displaced supracondylar elbow fractures were reviewed. Data elements recorded from the electronic medical record (EMR) included patient age, gender, height, weight, handedness, date, time, location, mechanism, Gartland classification, concurrent injuries, and neurovascular status. Results: In this study, there were 42 males and 33 females. The average age was six years. Some 70 of the 75 patients were older than the age three. One fracture was open, nine fractures had a pucker sign, seven presented with a nerve palsy, four presented without a pulse, and seven patients presented with an additional ipsilateral distal radius fracture. All fractures were the result of a fall. Falls from playground equipment resulted in 29 fractures. There were 10 from falls off of furniture, six from falls during sports, three from falls on the stairs, and three from fall off of bikes. The remaining fractures resulted from running, tripping, falling from a toy ball, sled, tree, wagon, fence, bounce house, van, deck, power wheels car, ATV, and a go-cart.Some 64 fractures were transferred from 27 different outside hospitals. Eleven fractures presented directly to the ED. Twenty-six fractures occurred during the summer, 20 occurred in the autumn, 6 occurred in the winter, and 23 occurred during the spring. Some 35 fractures occurred at home, 30 on the school grounds, four in a gymnasium, four in a park, one at a farm show, and one in a parking lot. Some 25 fractures were treated between midnight and 8 am, 16 were treated between 8 am and 5 pm, and 34 were treated between 5 pm and midnight. Conclusion: Pediatric supracondylar fractures are common in children, and many of them require operative intervention. This study examined the most important aspects of supracondylar fractures. This update provides a look at the clinically important aspects of supracondylar fractures and compares them to previous teachings and canon. Despite the advancement and changes in recreational equipment that children are using, children are still sustaining supracondylar fractures in the most common ways including falls from playground equipment and falls from standing.

Effect of oxy-hydrogen blending with gasoline on vehicle performance parameters and optimization using response surface methodology

ABSTRACTRapid decline in fossil fuel reservoirs has attracted researchers to use a variety of fuel blends in Spark ignition (SI) and Compression ignition (CI) engines demonstrating similar performance and lower emissions. Oxy-hydrogen gas obtained through electrolysis has been successfully tested for this use. This paper presents a two wheeler chassis dynamometer based study of a two wheeler loaded with newly developed single cylinder variable compression ratio (VCR) engine utilizing different blends of gasoline and oxy-hydrogen gas. Variation in fuel average performance (FAP), wheel power (WP) and acceleration performance (AP) due to oxy-hydrogen blending with gasoline is studied and compared with neat gasoline at five different gears. Further multi objective optimization of FAP and WP is carried out using response surface methodology (RSM). Regression models are postulated for predicting FAP and WP at different levels of compression ratio (CR) and oxy-hydrogen gasoline blends. Interaction between CR and oxy-hydrogen-gasoline blending is also studied and discussed. Modification carried out on an engine improves vehicle performance parameters and oxy-hydrogen gasoline blending further enhances the improvements. Maximum FAP and WP in top gear is obtained at highest CR of 11.57:1 and a oxy-hydrogen gasoline blend with 112.558 ml/min flow rate of oxy-hydrogen gas.

UGV with a distributed electric driveline: Controlling for maximum slip energy efficiency on stochastic terrain

Energy saving has been a prominent concern of ground vehicle Original Equipment Manufacturers and research agencies for decades. The search for technological advances that can increase energy efficiency of vehicles has been a relentless quest. The framework of research on energy efficiency improvements has been considerably extended after the introduction of fully electric vehicles with electric motors that individually drive each wheel, i.e., In-Wheel Motors (IWM). Although incoming IWM vehicles can significantly decrease driveline power losses and, thus, improve vehicle energy efficiency compared to conventional mechanical driveline systems, one technical problem related to the vehicle-tire-terrain interaction needs to be addressed in fully electric terrain vehicles. These vehicles are still lacking strategies to manage power distribution between the drive wheels, which are not connected by a driveline system anymore, with the purpose to minimize slip power losses at all tires and maximize vehicle slip energy efficiency. Inappropriate power delivered to each of the wheels, which run in different stochastic terrain conditions, can deteriorate slip energy efficiency of a vehicle with four individually driven wheels. The research work presented in this article addresses the problem of wheel power distribution for an unmanned ground vehicle (UGV) with four IWMs.The goal of this study was to analytically establish and determine conditions for the wheel power split that corresponds to the maximum slip efficiency of the IWM UGV, design a control algorithm that implements the conditions, and verify the effectiveness of the control in experimental research of the vehicle on deformable terrain. The article presents a terramechanics-based IWM UGV mathematical modeling that integrates both vehicle, electric-motor, and wheel dynamics with stochastic soil characteristics. The control algorithm is based on the inverse dynamics approach to control the wheel angular velocity to overcome stochastic terrain load torque and to satisfy a required program of UGV motion given by a UGV velocity profile. Each wheel angular velocity is controlled by varying the wheel torque using a control-by-acceleration principle that provides each wheel with the required angular velocity and the tire rolling radius in the drive mode. Experimental research work, including lab tests at the UAB Vehicle and Robotics Engineering Lab and soil bin experiments of the IWM UGV at the USDA-ARS National Soil Dynamics Lab, was conducted to validate the analytical models and control algorithm.It was found that maximum IWM UGV slip energy efficiency is achieved if the electric motors are controlled to provide the same tire slippages at all four wheels by zeroing the kinematic discrepancy between the theoretical linear velocities of the wheels. At this condition, the total electric current drawn by all four DC motors was minimum. The maximum IWM UGV slip energy efficiency of 89.3% was achieved at a mean tire slippage value of 11.1% on Norfolk Sandy Loam (NSL) soil.