The paper describes the technique of comparing fundamentally different types of transverters rotors, namely generators with electromagnetic excitation and magnetoelectric generators. In all embodiments of the comparative analysis it is necessary to compare power capabilities of electrical machines made with different devices in excitation system (permanent magnets, excitation coils), which in principle cannot be implemented without knowing and comparing the magnetic characteristics of the power generators and inductors. To unify the content and progress of computational studies on determination of electromagnetic parameters of generators with different excitation systems and gaining on this basis visual representations of its advantages and disadvantages it is advisable to represent used in the calculations of generators characteristics of permanent magnets and electromagnets in the form of identical form and content analytic or graphic dependencies. This is about the dependence of the magnetic flows in calculated sections of the element excitation systems (in their neutral section Фэм and Фм from magnetomotive force of excitation system F3M и Фм). Most simply this problem is solved by bringing the magnetic characteristics of the electromagnets to the same form and with the same parameters and concepts as the magnetic characteristics of the permanent magnets. As a result of researches it is established that widely used in automobile and tractor electrical equip-ment permanent magnets-ferrites fabricated by powder metallurgy from a mixture of crushed iron oxide and strontium owing to the relatively low level of magnetic energy and low values of residual induction is unable to provide the same level of magnetic properties of the inductors that have the inductors of the generators with electromagnetic excitation, and therefore, their use in automotive generators should be considered inappropriate.

Methane, as an alternative to traditional motor fuels, is the most perspective for the incoming decades of the current century. The most widely spread method of the modification of diesel engines for operating with methane is a conversion of a basic model by changing both the way of ignition - compulsory spark ignition instead of self-ignition by compression, and the method of power control - quantitative, with the help of a throttle in case of a gas version, instead of qualitative in a diesel version. The main task of such conversion is to achieve the best possible energy and economic performance of the engine. Moreover, the peculiarity of the operation procedure of the gas engine, the necessity to avoid detonation combustion, should be taken into account. Consequently, in the process of converting a diesel engine into a gas one manufacturers have to decrease both the compression ratio and boost pressure, which leads to decline in engine efficiency. The authors found out, that there is a potential possibility to achieve much better eco-nomic and power characteristics of gas engines by applying Miller cycle to the operation procedure. In this case it becomes possible having very high geometric compression ratio and corresponding high val-ues of gas expansion to obtain relatively low values of actual compression ratio. This is the value that can lead to detonation combustion. The program of calculating the characteristics of operation procedure of Miller-cycle gas engines was worked out. The authors suggested a system of calculation, according to which detonation behavior is estimated on the basis of actual data of a particular model of the engine. Due to such analyses of the particular model of the engine we found out actual maximum values of compression pressure and compression temperature, which do not lead to the onset of detonation. So it may be stated that the parameter value that significantly increases the overall efficiency of the Miller-cycle gas engine, created on the base of Kamaz engines, is found.

The article is describe the results of experimental investigations of forced fluid cooling of friction pairs in wet clutches on their thermal load. It is found that forced fluid cooling of the friction clutch can significantly increase the time of engagement and slipping in comparison with the time of operation similar couplings presently used on tractors and automobiles. It is found that at steady clutch disc temperature greatest influence parameters such as the pressure on the friction surface, the amount of cooling oil and its temperature in the inlet area of friction and has a much smaller effect change in the relative sliding speed of the rubbing surfaces. With increasing pressure on the disc friction surfaces with 0,501 to 2,82 MPa at specific consumption of oil 6,810-3 m3/(m2s) and the constant rotation frequency of 1000 min-1 a steady-state temperature is reduced by 15 % (from 143 to 125 °C). Therefore, by increasing the friction power 165 % (from 24,92 to 9,39 kW) temperature of clutch disc increases only by 75 %. With the increasing of specific oil consumption on the friction surface by 20 % (from 5,65 10-3 to 6,8 10-3 m3/(m2s)) at a pressure of 2,06 MPa and a constant speed of 1000 min-1 a steady-state temperature is reduced by 15 % (from 143 to 125 °C). The increasing in the at a speed of 100 % (from 500 to 1000 min-1) and, respectively, and friction power by 52 % (from 16,33 to 24,92 kW) at the pressure of 2,82 MPa and a permanent specific consumption of oil increases steady disk temperature by 19 % (from 122 to 145 °C). Based on the results of experimental studies found that increasing friction power per 1 kW due to the gain of a pressure on the friction surface leads to growing of friction disc temperature at the average of 4 °C, but due to the gain of disk rotation speed - at the average of 2,5 °C.

The studies were performed to improve workflow of hydraulic automatic control systems of the tillage units. Tillage quality should not deteriorate. Working bodies of tillage machines have to be moved automatically. Automated devices can be separated into two groups: direct and indirect action. It is preferable to indirect action. The article presents analysis of automatic devices used into tillage machines. Automatic control systems can be hydraulic, electro-hydraulic and pneumatic. Mechanical systems are not effective. Hydraulic systems are cheaper electric and pneumatic. They provide best of energy and quality indicators of technological process of tillage. Automatic control systems are uses draft forces, hitch position, depth of the implement, speed, acceleration and other sensors. Method of computer modeling and optimization of hydraulic automatic control systems of tillage units was developed. Results of computer modeling of hydraulic automatic control systems help to select direction of improving quality and energy indicators of technological process of tillage. Optimized combine implement depth and draft control system of arable unit allow reducing deviation the draft force of the plow; deviation of the depth of plowing is equal to or smaller than agro-technical requirements. Deviation of the draft force was decreased to 13.5 % for deviation specific soil resistance - 20 %, depth of plowing - 0.21 m, deviation of the depth of plowing - 0.019 m (9 %). Deviation of the depth of plowing may be decreased to 0.010 m (4,8 %), but deviation of the draft force shell be increased up to 16.2%. Optimized hydraulic automatic control system of garden tiller with a trapezoidal mechanism leaves smaller untreated soil area from 1.37-1.46 times.