scholarly journals Mechanical Devices for Mass Distribution Adjustment: Are They Really Convenient?

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1820
Author(s):  
Massimiliano Varani ◽  
Michele Mattetti ◽  
Mirko Maraldi ◽  
Giovanni Molari
Keyword(s):  
Weight Distribution ◽  
Rear Wheel ◽  
Front Wheel ◽  
Original Position ◽  
Fuel Saving ◽  
Wheel Drive ◽  
Loam Soil ◽  
Mechanical Devices ◽  
Four Wheel Drive ◽  
Engine Power

Since the introduction of four-wheel drive (4WD) and especially front wheel assist (FWA), many studies have been conducted on the optimal weight distribution between tractor front and rear axles because this influences traction efficiency. The aim of this paper is to evaluate the traction and efficiency advantages in the adoption of mechanical ballast position adjustment devices. The tested device is an extendable ballast holder mounted on the front three-point hitch of the tractor, able to displace the ballast up to 1 m away from its original position. An estimation of the fuel consumption during ploughing with the extendable ballast holder in different configurations was performed. Tractive performance was evaluated through drawbar tests, performed on loam soil with a 4WD tractor having a maximum engine power of 191 kW and a ballasted mass of 9590 kg. Results show that changing the tractor weight distribution over the range allowed by the extendable ballast holder produces limited effects in terms of tractive performance and fuel saving. The adoption of such devices is thus ineffective if other fundamental factors such as tyre pressure, choice of the front-to-rear wheel combination and lead of the front wheels are not considered during tractor setup.

Design and Performance Simulation of a Power-Integrated Transmission Mechanism

2013 ◽  
Vol 397-400 ◽  
pp. 388-392
Author(s):  
Chou Mo ◽  
Ji Qing Chen ◽  
Feng Chong Lan
Keyword(s):  
Hybrid Electric Vehicle ◽  
Rear Wheel ◽  
Front Wheel ◽  
Transmission Mechanism ◽  
System Structure ◽  
Performance Simulation ◽  
Operating Modes ◽  
Wheel Drive ◽  
And Performance ◽  
Four Wheel Drive

The power system structure of a hybrid electric vehicle (HEV) critically affects the performance of the vehicle. This study presents a power-integrated transmission mechanism that can provide six basic operating modes that can be further classified into 15 sub-modes. Switching clutch conditions helps transmission achieve speed and torque coupling. The proposed mechanism has CVT capability and an extended range capacity, and it is applicable to front-wheel-drive, rear-wheel-drive, or four-wheel-drive HEVs. A performance simulation on power and economy via Matlab and Cruise software demonstrates that the performance of the proposed transmission mechanism meets the target. Therefore, the mechanism is a feasible candidate for use in HEVs.

Analyses of the Relations Between Driving Types and Regenerative Braking in Electric Vehicles

2014 ◽  
Vol 926-930 ◽  
pp. 896-900
Author(s):  
Jin Long Liu ◽  
Zhi Wei Gao ◽  
Jing Ming Zhang
Keyword(s):  
Distribution Coefficient ◽  
Electric Vehicles ◽  
Theoretical Models ◽  
Rear Wheel ◽  
Front Wheel ◽  
Regenerative Braking ◽  
Force Distribution ◽  
Wheel Drive ◽  
Braking Force ◽  
Four Wheel Drive

The relations between Electric Vehicle (EV) drive arrangement and efficiency of regenerative braking were discussed. Firstly, conclusions were concluded according to the analyses of theoretical models. And then the validity of conclusions was proved by the simulations basing on the software of MATLAB/SIMULINK. The results indicate that the EV with four-wheel drive (4WD) pattern has the highest efficiency in regenerative braking mode. It also shows that whether the EV with front-wheel drive (FWD) pattern has higher efficiency than the EV with rear-wheel drive (RWD) pattern in regenerative braking mode depends on the braking force distribution coefficient.

Analytical Traction and Propulsion Analysis

2001 ◽  
Author(s):  
Junghsen Lieh
Keyword(s):  
Nonlinear Differential Equations ◽  
Rolling Resistance ◽  
Rear Wheel ◽  
Front Wheel ◽  
Inertia Force ◽  
Design Phase ◽  
Multiple Parameters ◽  
Electric Car ◽  
Wheel Drive ◽  
Four Wheel Drive

Abstract Conventional approach for vehicle traction and propulsion analysis used spreadsheets. This is inconvenient if one intends to vary a parameter, and it is even more difficult when multiple parameters are evaluated at the design phase. In this paper, it is intended to formulate two nonlinear differential equations representing road load and power consumption. By expanding inertia force, air drag, rolling resistance, gravitational force and tire tractive force, the equations can be simplified as the function of velocity v, i.e., s 1 v ˙ = s 2 - s 3 v 2 and m v ˙ = - r 1 v 3 - r 2 v + r 3 v , respectively. With these two equations, it allows engineers to use either numerical or analytical method to study key parameters at the design phase. To demonstrate the effectiveness of these equations, Wright State’s electric car model is used. The results for front-wheel drive (FWD), rear-wheel drive (RWD) and four-wheel drive (4WD) cases are presented.

Slip Calculation and Analysis for Four-wheel Drive Tractors

2005 ◽  
Vol 1 (1) ◽  
pp. 7-31 ◽  
Author(s):  
Márk Szente
Keyword(s):  
Rear Wheel ◽  
Front Wheel ◽  
Wheel Slip ◽  
Wheel Load ◽  
Low Profile ◽  
Wheel Drive ◽  
The Difference ◽  
Special Respect ◽  
Four Wheel Drive ◽  
Drawbar Pull

The objective of the research of tires was to determine the dynamic rolling radius and to apply it to wheel slip calculations with special respect to vertical wheel load and to tire inflation pressure. It is typical of mechanical four-wheel drive tractors that there is a definite additional power in the tractor power chain. This additional power is dependent on the difference between the front wheel and rear wheel peripheral speeds. Further-more, the purpose was to determine the effect of additional slip on four-wheel drive tractors operated without drawbar pull. Experiments were performed on asphalt surfaces and fields. A new measurement method was developed, and a device was constructed for the implementation of three tractor wheel drive operational modes (four-wheel drive, rear-wheel drive and front-wheel drive). As the result of the experiments, a relationship was found to describe the dynamic rolling radius for low-profile radial tires tested on rigid road surfaces. On this basis, the classical slip calculation method was modified. This phenomenon appears only on hard roads and soil surfaces with high adhesion coefficients and only within the low drawbar pull range.

Test Results: Vehicle Responses to Simulated Drag Caused by Front Tire Tread Detachment — The Effect of Scrub Radius and Speed

2018 ◽  
Author(s):  
Mark W. Arndt ◽  
Stephen M. Arndt
Keyword(s):  
Lateral Displacement ◽  
Rear Wheel ◽  
Lateral Acceleration ◽  
Steering Wheel ◽  
Slip Angle ◽  
Yaw Rate ◽  
Wheel Drive ◽  
Steady State Responses ◽  
Four Wheel Drive ◽  
Left Front

The effects of reduced kingpin offset distance at the ground (scrub radius) and speed were evaluated under controlled test conditions simulating front tire tread detachment drag. While driving in a straight line at target speeds of 50, 60, or 70 mph with the steering wheel locked, the drag of a tire tread detachment was simulated by applying the left front brake with a pneumatic actuator. The test vehicle was a 2001 dual rear wheel four-wheel-drive Ford F350 pickup truck with an 11,500 lb. GVWR. The scrub radius was tested at the OEM distance of 125 mm (Δ = 0) and at reduced distances of 49 mm (Δ = −76) and 11 mm (Δ = −114). The average steady state responses at 70 mph with the OEM scrub radius were: steering torque = −24.5 in-lb; slip angle = −3.8 deg; lateral acceleration = −0.47 g; yaw rate = −8.9 deg/sec; lateral displacement after 0.75 seconds = 3.1 ft and lateral displacement after 1.5 seconds = 13.1 ft. At the OEM scrub radius, responses that increased linearly with speed included: slip angle (R2 = 0.84); lateral acceleration (R2 = 0.93); yaw rate (R2 = 0.73) and lateral displacement (R2 = 0.59 and R2 = 0.87, respectively). At the OEM scrub radius, steer torque decreased linearly with speed (R2 = 0.76) and longitudinal acceleration had no linear relationship with speed (R2 = 0.09). At 60 mph and 70 mph for both scrub radius reductions, statistically significant decreases (CI ≥ 95%) occurred in average responses of steer torque, slip angle, lateral acceleration, yaw rate, and lateral displacement. At 50 mph, reducing the OEM scrub radius to 11 mm resulted in statistically significant decreases (CI ≥ 95%) in average responses of steer torque, lateral acceleration, yaw rate and lateral displacement. At 50 mph the average slip angle response decreased (CI = 87%) when the OEM scrub radius was reduced to 11 mm.

Analysis of Vehicle Lateral Response During Regenerative Braking in a Turn

2016 ◽  
Author(s):  
C. S. Nanda Kumar ◽  
Shankar C. Subramanian
Keyword(s):  
Rear Wheel ◽  
Front Wheel ◽  
Lateral Acceleration ◽  
Regenerative Braking ◽  
Steering Wheel ◽  
Slip Angle ◽  
Lateral Response ◽  
Wheel Drive ◽  
Reference Track ◽  
The Impact

Regenerative braking is applied only at the driven wheels in electric and hybrid vehicles. The presence of brake force only at the driven wheels reduces the lateral traction limit of the corresponding tires. This impacts the vehicle lateral response, particularly while applying the regenerative brake in a turn. In this paper, a detailed study was made on the impact of regenerative brake on the vehicle lateral response in front wheel drive and rear wheel drive configurations on dry and wet asphalt road surfaces. Simulations were done considering a typical set of vehicle parameters with the IPG CarMaker® software for different drive conditions and braking configurations along the same reference track. The steering wheel angle, yaw rate, lateral acceleration, vehicle slip angle, and tire forces were obtained. Further, they were compared against the conventional all wheel friction brake configuration. The regenerative braking configuration that had the most impact on vehicle lateral response was analyzed and response variations were quantified.

Paper 7: Ground-Drive Systems for High-Powered Tractors

1969 ◽  
Vol 184 (17) ◽  
pp. 58-67
Author(s):  
L. E. Osborne
Keyword(s):  
Soil Compaction ◽  
Rolling Resistance ◽  
Theoretical Work ◽  
Wheel Drive ◽  
Drive Systems ◽  
Four Wheel Drive ◽  
Work Done ◽  
Tyre Wear ◽  
Engine Power

Attempts to solve the problem of transmitting high engine power to the drawbar have resulted in a variety of tractor designs. Measured rates of work on two- and four-wheel drive tractors and a tracklayer showed that while the four-wheel drive had the highest output, the tracklayer was more efficient for heavy draught operation. The two-wheel drive machine has a higher rolling resistance than the four-wheel drive and methods of measuring rolling resistance are described. The paper discusses the reasons that different performances are obtained from two- and four-wheel drive vehicles of the same engine power, and highlights some of the advantages to be gained. Previous theoretical work on two- and four-wheel drive tractor performance and on transmissions for four-wheel drive is also discussed, together with practical limitations on tyre size for operation under certain conditions. A small survey to measure tyre and track wear is described and a method is suggested of relating tyre wear to work done by quoting tyre costs per gallon of fuel used. The paper concludes with a few comments on soil compaction.

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