THEORETICAL SUBSTANTIATION OF RECOVERY OF HIGH PRESSURE FUEL PUMPS OF MARINE ENGINES (HPPU) BY DIFFUSION METALLIZATION OF PLUG PAIRS

ABSTRACT

Ensuring the work of repair enterprises in a market economy improving the level of its production depends on maintaining competitive characteristics. This can be attributed to the constant improvement of the repair technology of plunjer pairs of high-pressure fuel pumps of ship engines. Until now, a number of methods have been developed and implemented by research institutes and operational enterprises for the restoration of preseason parts of high-pressure fuel pumps of ship engines.

АННОТАЦИЯ

Обеспечение работы ремонтных предприятий в условиях рыночной экономики, повышение уровня их производства зависит от сохранения конкурентных характеристик. Это можно объяснить постоянным совершенствованием технологии ремонта плунжерных пар топливных насосов высокого давления судовых двигателей. До настоящего времени научно-исследовательскими институтами и эксплуатационными предприятиями был разработан и внедрен ряд методов восстановления предсезонных деталей топливных насосов высокого давления судовых двигателей.

Keywords: plunger pairs, recovery, ship engines, high-pressure, fuel pumps.

Ключевые слова: плунжерные пары, рекуперация, судовые двигатели, высокого давления, топливные насосы.

Introduction

The essence of each of them is determined by the goals and capabilities of repair enterprises.

The wide nomenclature of restored details and the variety of methods for their restoration are among the pressing problems of choosing the most optimal option of many technological solutions for specific production conditions. The recovery methods of the presection details of the high-pressure fuel pumps of ship engines work to ensure that the costs of their recovery are minimal when implemented. In this case, it is necessary to take into account the multiplicity of factors affecting the repair enterprise of ship engines and the technology of that enterprise.

In addition to ensuring the operating conditions, the technological process of restoring the preseason details of high-pressure fuel pumps of ship engines should be economically profitable for repair enterprises (mainly in a market economy). In this coherent relationship, it is important to understand that complex approaches and numerous factors: constructive, technological, production, operation, etc.  it is advisable to use its compatibility.

In modern times, improving the reliability of high-pressure fuel pumps of ship engines is one of the pressing issues for the national economy. So, the processing of the technique 20...30 times decreased, and the delivery of spare parts decreased dramatically.

Due to this, the demand for the restoration of worn prefabricated parts of high-pressure fuel pumps of ship engines is growing. Therefore, one of the important issues is the choice and justification of the method of restoration of worn parts during the development of the process of technological recovery of plunger pairs of high-pressure fuel pumps of ship engines. [1,2]

Main part

Analysis of the literature and research has shown that in modern times, the evaluation of methods for the restoration of pre-section details of high-pressure fuel pumps of ship engines is often carried out according to general criteria:

                                                                 (1)

                                                 (2)

One of the optimal methods for the restoration of presection details of ship engines is the method with the lowest value of the G_i factor. It is expedient to determine the optimality criterion for individual details according to formulas (1) and (2). As a rule, repair companies incur certain costs associated with the restoration of parts, and the optimal method for one detail can not be considered optimal for the whole group of details.

Also, the analysis of expressions (1) and (2) shows that the С_В and К_Д values are the same when evaluating the recovery method. Thus, given the current trends in the production of ship engines and the economy, the importance of these indicators as a whole is not equal.

At the same time, when analyzing the cost and method of recovery of the annual production program for the restoration of prefabricated parts of high-pressure fuel pumps of ship engines, it is expedient to divide the program (N) into variable (C_d) and fixed (C_O) costs. In this case, depending on the annual program, the cost of restoration of details is determined by the following expression:

                                                        (3)

The advantage of this method is that for the first time an economic approach based on technical and economic criteria has been applied to evaluate the methods of restoration of pre-section details of ship engines. This is due not only to the cost of restoration of parts, but also to the cost of the process of preparation for mechanical processing after their restoration.

Considering the works of [1, 2] professor I.S. For the first time, Levitsky proposed to choose a rational method of recovery, taking into account the transport costs and the program for the delivery of worn parts:

                                   (4)

Substituting these values in expression (4), we obtain a formula for determining the coefficients А_В and В_В (Figure 1). If the П₁ program is insignificant, we obtain expressions that help to calculate the value of the coefficients А_В and В_В by taking the cost of restoring this detail and calculating the cost of its restoration in different ways (Figure 2).

Figure 1. Determination of the coefficients А_В and В_В, depending on the cost of repairing the exact details of high-pressure fuel pumps of ship engines and the cost of the part

Figure 2. Determination of the coefficients А_В and В_В, depending on the cost of the recovery process with different options[3,5]

                          (5)

(5) refers to a feasibility study that takes into account and estimates the cost of repairing the pre-section details of high-pressure fuel pumps for ship engines as a whole.

Thus, the study of these works shows that it does not give a perfect objective assessment of the technical level of the technology of restoration of precession details of high-pressure fuel pumps of ship engines. In addition, indicators of different origins are taken into account in the assessment, but no reliable method for determining their quantitative coefficients has been developed. Also, the value of these and other indicators depends on various socio-economic aspects of the country's economic development.

Modern new approaches with rational (optimal) substantiation of the methods of restoration of worn details are given in the works of professor A.N.Batishev. He proposed to optimize the technological process of recovery according to energy criteria. It takes into account the longevity coefficient and all energy costs, as well as live labor energy from the production of necessary materials to the final processing of parts.

                                                       (6)

The author of the proposed criterion notes that due to the impact of prices on energy carriers (mainly their increase), it can not always meet the economic criteria of the enterprise.

In this regard, taking into account the economic interests of specific ship repair enterprises, it was proposed to optimize the methods of restoration of pre-section details of high-pressure fuel pumps of ship engines according to the combined (complex) criterion. It takes into account costs, energy consumption, longevity and economic ratio:

                                            (7)

K₁, K₂, K₃, К₄ are determined during the restoration of the exact details of high-pressure fuel pumps of ship engines with diffusion chromium in vacuum. Research by the authors of [4,5] shows that this criterion shows a more objective assessment of the effectiveness of detail restoration methods compared to the feasibility study.

This criterion will allow for an objective assessment of the method of restoration of worn parts.

                                                   (8)

Therefore, in order to justify the optimal recovery method, it is necessary to take into account the maximum number of factors that affect the total amount of certain costs.

Conclusions

1. In modern times, when strengthening and restoring the preview details of high-pressure fuel pumps of ship engines, repair facilities are subject to strict conditions from different points of view: economic, technological process, working conditions, environmental safety and energy costs.

2. When developing a mathematical model, it is more expedient to use the theoretical foundations of production functions. In this case, it is possible to assess the effectiveness of certain costs that make up the technological process and choose the optimal method of recovery of worn parts of high-pressure fuel pumps of ship engines.

3. The theoretical basis of the technological process of restoration of worn parts should be based on the methods of restoration to ensure the required reliability of the restored parts. The optimal method of restoring worn parts will solve a number of problems by minimizing the cost of operating high-pressure fuel pumps of ship engines.

Reference:

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3. Антропов Б., Слабов Е. Еще раз о пылевом износе//Автомобильный транспорт, 2001, № 9, с. 35-38 
4. Андрейкив А.Е., Чернец М.В. Оценка контактного взаимодействия тру­щихся деталей машин. Киев, Наукова думка, 1991, 154 с.
5. Антипов В.В. Износ прецизионных деталей и нарушение характерис­тики топливной аппаратуры дизеля. М., Машиностроение, 1972, 176 с.