K.P. Pandey

A review on contact area measurement of pneumatic tyre on rigid and deformable surfaces

The theoretical and empirical models which have been proposed for predicting the contact area of pneumatic tyres on rigid and deformable surfaces are examined. Theories developed for rigid and deformable surfaces are capable of predicting contact area of pneumatic tyres to some extent whereas empirical models have limitations of their test range. These models do not have a constant numerical base because of different assumptions and constants. The paper also describes the various techniques adopted for tracing the tyre-surface contact area.

The deflection and contact characteristics of some agricultural tyres with zero sinkage

Abstract The vertical deflection, contact area, and ground pressure of three agricultural tractor rear tyres (11.2–28, 12.4–28, 13.6–28) were investigated at different normal loads and inflation pressures on a firm surface. A linear mathematical model was evolved to establish relationship among different parameters. The model could be used to represent tyre behaviour under varying operational parameters.

Matching tyre size to weight, speed and power available for maximising pulling ability of agricultural tractors

The desirable weight-to-axle power ratio for agricultural tractors is determined by the necessity for the optimum utilisation of the available axle power to produce the required drawbar pull at a preselected slip. For a vehicle designed to operate in a given speed range, the weight-to-axle power ratio should be within a particular limit, so that a specific level of conversion efficiency can be maintained. In this paper attempts have been made to select suitable tyres for Indian two-wheel drive tractors operating in sandy clay loam soils on the basis of weight-to-power utiisation and maximum pull-to-optimum weight ratio at a preselected slip using the developed traction prediction equations. A comparison has also been made between the desired and actual weight on a single traction wheel and suitable tyre and tyre normally fitted in Indian two wheel drive tractors up to 35 kW.

Traction data analysis in reference to a unique zero condition

The lack of a unique definition for the zero condition leads to innumerable zero conditions resulting in different amounts of net traction at the same value of slip. In this paper, an attempt has been made to discuss various aspects of different zero conditions and finally result in a unique definition of the zero condition. Based on this definition, a traction prediction model using mobility number approach has been developed to evaluate the performance of tractor tyres in sandy clay loam soils.

Modelling power requirement for traction tyres with zero sinkage

Abstract A model was developed by dimensional analysis to predict the gross traction at zero net traction for traction tyres (11.2–28, 12.4–28, 13.6–28) on a hard surface. Different parameters that affect the torque requirement, namely tyre size, tyre deflection, axle load, and rolling radius, were considered for the analysis. Experiments were conducted to study the effect of various wheel and system parameters on torque and energy consumed per unit distance travelled. The model developed predicts the torque requirement in an acceptable range and can be used as a reference for further traction studies of these tyres in various soils.

A visual basic program for predicting optimum gear and throttle position for best fuel economy for 32kW tractor

A fuel consumption model was developed with coefficient of determination 0.99.Used in visual basic program for predicting optimum gear and throttle position on basis of minimum fuel consumption.Software was validated with experimental data. A visual basic program was developed to determine the optimum gear and throttle position on the basis of minimum fuel consumption per hectare for ploughing, cultivating and harrowing operations. The program provides an intuitive interfaces by linking database such as tractor, tyre and implement specifications, draft and tractions model constants, fuel consumption model, soil and operating conditions to predict the minimum fuel consumption of selected model. The fuel consumption model was developed by conducting PTO test under variable throttle and load conditions. The coefficient of determination (R2) value for developed model was found close to 0.99. The program was validated with the data collected from the field experiments conducted with a 32kW PTO power 2WD tractor and 2-bottom reversible MB plough under different operating conditions. It was found that the developed program predicted optimum gear as L3 (6.9km/h) at 2066rpm and on an average under predicted slip values by 50-62%, draft by 4-20% and over predicted fuel consumption by -19 to 52% in the depth range of 18-22cm.