Modeling of Operation Processes of a Motor Grader Engine During Work Under Unsteady Load

We proposed a model of operation processes of a motor grader engine under unsteady load during technological processes of road construction works. Theoretic dependences of operation processes of a diesel motor grader engine, described by third order differential equations, were determined. The developed mathematical model of operation processes of a motor grader engine under unsteady mode makes it possible to employ known theoretical provisions to improve the system of air regulation in the commercially available motor grader engines. The model is a description of patterns of influence of differential equations coefficients and the load character on a change in the rotation rate of crankshaft of engine, cyclic fuel supply and hourly fuel consumption. Numerical modeling was carried out of load throw off and load gain of a motor grader engine using third-order differential equations in relative magnitudes. It was established that at a decrease in the values of coefficients of differential equation the transition process proceeds more intensively. In this case, time of delay in the response to disturbance and the duration of damping the oscillation process decrease. The proposed model would ultimately optimize engine performance under unsteady modes

A Method of Evaluating Vehicle Controllability According to the Dynamic Factor

The study has explored one of the most important performance properties of the vehicle, which determines road traffic safety, – control in a steady mode. A method has been suggested for evaluating the stability of a vehicle against yaw with regard to the dynamic factor. We have found a dependence of the dynamic factor on the design and operational parameters of the vehicle. The dynamic factor can be reduced through achieving a neutral steering of the vehicle by controlling the ratio of the total lateral rigidity of the tires of the front and rear wheels. It has been determined that a change in the tire air pressure, measured by the developed algorithm, improves vehicle stability against yawing and thus contributes to traffic safety. In the example of the truck Ural-4320, the suggested method was used to determine the total lateral stiffness of the wheels under the condition of ensuring the vehicle's neutral steering. The study has revealed that in the case of an equipped vehicle it is necessary to reduce the tire pressure in the wheels on the equalizer trolley in correlation to the air pressure in the tires of the front wheels. The research results can be used both in operating the existing vehicles and for designing new ones