Oil crisis and sharp increase of oil and petroleum market prices, resource limitation fastened the search for alternative energy sources. Among alternative energy sources renewable and especially received from vegetable biomass (fuel alcohol, vegetable oils) are of the greatest interest. With the account of this the article gives the results of studying the peculiarities of the bio-Diesel operational cycle and possibilities to adapt existing Diesels to biofuel. It has been determined that substitution of the Diesel fuel (DF) with rape-seed oil (RSO) and biofuel increases maximal and intermediate injection pressure, earlier start and greater injection duration, loss in frequency and oscillatory amplitude in the pressure pipeline after completing the injection. When RSO is used there appear increased inside lacquer film on the blowgun; which results in the needle valve immobility down to hanging up; needle valve immobility leads to the time lag of inlet and lengthening of the injection, increase in maximal injection pressure. There is quality loss of spraying the fuel, increase in non-uniformity and medium volume diameter of fuel drops, as well as penetration of the fuel jet into the air medium. Higher viscosity of the biofuel increases the injection rate due to leakage decrease in plunger pairs of diesel fuel injection pumps (DFIP).

Wear and fatigue are phenomena that limit to some extent the reliability of mechanical systems in almost any modern machine. Traditionally, reliability indicators of power parts of machines are evaluated differentially, according to individual criteria. This is often justified, since in the design of machines there are a lot of parts that “work” only on fatigue under repeated-variable loads. There are also parts that “work” exclusively in conditions of friction, sliding or rolling. However, in reality there are also mechanical systems in which a combination of both phenomena takes place. For example, these are such systems as: “crankshaft-connecting rods of piston engines”; “gearing, camshaft-cam follower”; “axis bearings of centrifugal machines”; “details of the chassis of the car and tractor”; “wheels of rolling stock-rails of the railway track” and a large number of other critical structural elements of various machine components. Consequently, the entire range of scientific research in the design, manufacture and repair of machines should be aimed at ensuring fundamental transformations in technology and creating the prerequisites for the scientific justification of both methods for calculating the accuracy of mechanisms and all technological problems, from the design of the technological process as a whole to a thorough mathematical modeling of its individual components. The currently used methods for calculating the strength by safety factors in a deterministic formulation do not sufficiently take into account the scattering of the characteristics of fatigue resistance, the random nature of the loading of parts and do not provide an estimate at the design stage of the distribution function of the resource of machine elements. At the same time, it is possible to correctly determine the indicators of machine reliability and durability on the basis of these functions.

The main reason for the emergence of the operational characteristics of tractor diesel engines is the uneven fuel consumption. Fuel equipment is one of the most responsible systems of diesel engines. The purpose of the study was to improve the fuel efficiency of an agricultural tractor diesel engine by using an injector sprayer. Modernization of the needle of the atomizer of the fuel injector is carried out by directing its guiding surface of the helical groove at an angle α, advancing the direction of the axisymmetric fuel pressure. This includes the fuel injector needle, as it is likely to be skewed, stuck, and dependent. The novelty of this design is protected by the patent of the Russian Federation RU 2231673. To assess the fuel efficiency, natural experiments of a diesel engine with serial and modernized injectors were carried out. The introduction of new technical equipment in the fuel equipment has led to the achievement of diesel engine power by 8 … 12% and the rate of retention of fuel consumption by 3 … 4%.

Проведен анализ надежности форсунок дизельных двигателей, в ходе которого было установлено, что причиной снижения работоспособности является потеря герметичности запирающего конуса распылителя, заклинивание иглы в направляющей корпуса и закоксовывание распылителей форсунок. Установлено, что на течение топлива по каналам форсунки распылителя существенное влияние оказывают граничные условия, обусловленные силами молекулярного взаимодействия, действующими на границе раздела жидкой и твердой фаз. В прецизионном зазоре под действием этих сил происходит адсорбция полярноактивных молекул жидкости на рабочих поверхностях сопряженных деталей, на которых через некоторое время формируются пограничные слои. На интенсивность процесса облитерирования каналов и характер течения жидкости через зазор существенное влияние оказывает загрязненность жидкости твердыми и вязкими включениями. Для повышения долговечности распылителей и форсунок в целом, снижения износа их рабочих поверхностей, уменьшения влияния указанных факторов нами предложена модернизация иглы распылителя. На игле распылителя выполнена винтовая канавка в направляющей части иглы под углом , с радиусом r, которая способствует осесимметричному давлению на иглу жидкости, перетекающей из канавок в зазор S между корпусом и направляющей части иглы распылителя дизельной форсунки. За счет наличия топлива в винтовом канале происходит смазывание, а также смягченный закручивающий удар конуса иглы о седло корпуса. При проведении исследований было установлено, что увеличение суммарного зазора коэффициента сопротивления щели не снижается ниже 0,4. Поэтому можно выполнить объем винтовой канавки, равной 0,5…0,9 от зазора V .Ключевые слова: дизельная форсунка, распылитель, работоспособность, ресурс, долговечность, расход топлива, износостойкость.The analysis of the reliability of diesel engine injectors, during which it was found that the cause of reduced efficiency is the loss of tightness of the locking cone of the sprayer, the jamming of the needle in the guide housing and the pumping nozzles of the injectors. The SRT for the fuel flow through the channels of the atomizer nozzle is significantly influenced by the boundary conditions caused by the molecular interaction forces acting on the interface between the liquid and solid phases. In the precision gap, under the action of these forces, the adsorption of polar active liquid molecules takes place on the working surfaces of the conjugated parts, on which the boundary layers are formed after a certain time. The intensity of the process of channel obliteration and the nature of the liquid flow through the gap is significantly influenced by the contamination of the liquid with solid and viscous inclusions. To increase the durability of sprayers and injectors in General, reduce the wear of their working surfaces, reduce the influence of these factors, we propose a modernization of the needle of the sprayer. A screw groove in the guide part of the needle at an angle , with a radius r, is made on the needle of the sprayer, which promote...

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