Study of operability of the diesel fuel injection equipment in non-conventional conditions

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Introduction

To date, Russian and foreign scientists have proposed many different compositions of multicomponent mixed fuels (MMF) for use in diesel engines [1-4] as motor, as well as methods of high-temperature boosting. It is known that the effective and environmental performance of an internal combustion engine directly depends on the correct setting of the fuel supply equipment (FSE) and the nature of operation [5, 6]. Poor-quality tuning of the FSE leads to an increase in costs up to 30 ... 35%, reduces the resource of the internal combustion engines themselves by 1.5 ... 2 times, worsens their performance.

In general, FSE, which includes a mixture of diesel fuel (DF), rapeseed oil (RSO) and ethanol (E), is characterized as a microheterogenic coarse-dispersed concentrated emulsion of the reverse type - "water in oil", in which the polar dispersed phase is in a non-polar dispersion medium. The fragmentation of the dispersed system, associated with an increase in the interface, gives the MMF new physico-chemical and mechanical properties that can significantly affect the performance of the FSE [7].

High-temperature heating of DF (over 100 ° C) leads to a decrease in its kinematic viscosity. This circumstance undoubtedly affects the amount of cyclic fuel supply and the unevenness of its supply when changing the speed mode of operation. In addition, an increase in the thermal stress of the parts of the power supply system can cause abnormal situations, mechanical failures and breakdowns and, as a result, a decrease in the service life of the FSE.

Accordingly, the study of the operation of FSE on unconventional fuels, as well as under conditions of thermal forcing of diesel fuel, is of certain scientific interest.

Purpose and objectives

The purpose is to study the efficiency of diesel fuel equipment in non–traditional conditions. To achieve the goal, it was necessary to solve the following tasks: - to develop a device for heating diesel fuel on a test bench for diesel fuel injection systems; - to determine the characteristics of the operation of a diesel FSE on multicomponent fuel of various compositions; - to determine the characteristics of the operation of a diesel FSE on diesel fuel without heating and with heating up to 150^oC.

Research methods

The object of research was a high-pressure fuel pump YAZDA-773-40.28 diesel 4CHN 11.5/12.0 (D-245.5S2) complete with four-hole nozzles of closed type 455.1112010-50 (FD-22), with a sprayer and a hydraulically controlled needle, with a diameter of 0.32 mm sawing holes. The efficiency and performance characteristics of the fuel supply equipment (FSE) were studied when supplying preheated diesel fuel (DF) and multicomponent mixed fuel under conditions of external speed characteristics.

Fig. 1 - Test bench for fuel equipment KI-22210-02M-15

In the experimental study, a stand was used to adjust the KI-22210-02M-11 diesel fuel equipment (Fig. 1). The tests were carried out in accordance with GOST 10578-2020 [8] in two stages. At the first stage, pure diesel fuel according to GOST 305-2013 was used without heating, heated to 100^oC and heated to 150^oC.

At the second stage, comparative tests were carried out on multicomponent compositions of mixed fuels, including DF, cold-pressed RSO according to GOST-31759-2012 and rectified ethyl alcohol according to GOST 5962-2013. Multicomponent fuel mixtures were prepared using a mixing plant, the kinematic scheme of which is shown in Figure 2 [9].

The mixing plant included a housing, which is a truncated cone with windows for the supply of DF, E and RSO, at the bottom of which there is an outlet for the MMF. A rotating screw with blades is installed in the center. Inside the auger there is a perforated cylinder for overflow of excess fuels.

During operation of the mixing plant, DF enters the window 2, and ethanol and rapeseed oil through the window 3. The screw, when rotating with the blades 6, mixes the components, while the MMF begins to rotate inside. At the same time, the MMF moves to the exit window 4. Given that the volume of the MMF inlet is larger than the outlet, excess fuel arises. These surpluses are squeezed out by a rotating screw 5 through the holes of the perforated cylinder 7, then re-enter the entrance windows.

The following fuel compositions were used: DF-100%, DF-70% + E-15% + RSO-15%, DF-50% + E-25% + RSO-25%. The characteristics of the FSE operation under conditions of external speed characteristics were determined when the rotational speed changed from the starting speed - 100 min^-1 to the maximum speed – 1020 min^-1.

High-temperature heating of diesel fuel was carried out using a 3TF-2000DK technical electric heater and a specially designed confuser mounted on high-pressure tubes in front of the injectors (Fig. 3). Current fuel temperature readings were recorded by a Fluke 574 infrared thermometer (Fig. 4).

The mass content of the MMF components was measured on electronic scales, then the mechanical dispersion of the mixture ingredients was carried out at the mixing plant (Fig. 2).

Before the start of the tests, the serviceability of the injection pump itself and the set of injectors, the smoothness of the rail movement, the absence of fuel leaks and the correctness of their adjustments were checked [10].

The external high-speed characteristic of the injection pump with the regulator turned on was removed in the entire speed range.

Fig. 3 – Installation diagram of the 3TF-2000DK electric heater and the confuser

The cyclic fuel supply by pump sections was measured, and the uneven supply by sections was determined. The characteristics of fuel atomization were assessed visually. During the tests, knocks, jamming of the rails, local heating above +80^oC were not allowed.

Fig. 4 - Fluke 574 infrared thermometer

The parameters of the fuel supply process were determined and controlled for all high-speed modes of operation of the fuel pump, however, they were optimized primarily for the nominal mode, since they can only be partially optimized in other modes [10].

Results and discussion

Figure 5 shows the external speed characteristic of the YAZDA-773-40.28 pump when it is operated on a heated diesel engine.

The analysis of the curves shows that the parameters of the pump operation on pure diesel fuel correspond to the technical characteristics.

Heating of diesel fuel entails a slight decrease in the value of the average cyclic supply. So, if the value of the cyclic fuel injection pump at the nominal speed of its shaft at n = 900 min^-1 is qc = 0.090 ml / cycle, then when heating the fuel pump to 100^oC, there is a decrease in the supply value to qc = 0.088 ml / cycle.

Further heating of the fuel to 150^oC also causes a further decrease in the average cyclic supply to qc = 0.087 ml/cycle. This circumstance can be explained by a change in the physical volume of fuel due to heating. Initially, it was determined that the cyclic feed of a single section is unchanged. Let's take into account that the DF is heated to a high temperature near the nozzle. After injection, this fuel enters a measuring container, then cools down, as a result, the diesel fuel takes on a smaller volume [11, 12].

In parallel with the change in the cyclic supply of DF, its unevenness decreases, the unevenness of the supply at the nominal speed drops from 5.9% (DF without heating) to 5.0% (DF heated to 150^oC).

Mechanical failures in the operation of both the injectors and the fuel pump itself were not observed during the tests, which means that their reliability and durability are maintained.

Fig. 5 - External high-speed characteristics of the injection pump when working on a heated diesel engine: - diesel engine without heating; - DF at 100oC; - DF at 150oC

Figure 6 shows the external speed characteristics of the YAZDA-773-40.28 pump when working on DF and MMF of various compositions.

Fig. 6 - External high-speed characteristics of the injection pump when working on the MMF: - DF-100%; - DF-70% + E-15% + RSO-15%; - DF-50% + E-25% + RSO25%.

The analysis of the curves shows that the parameters of the pump operation on pure diesel fuel also correspond to its technical characteristics.

About the authors

Sergey A. Plotnikov

Author for correspondence.
Email: Plotnikovsa@bk.ru
ORCID iD: 0000-0002-8887-4591
SPIN-code: 4899-9362

Dr. Sci. (Engineering), Professor of the Technology of Mechanical Engineering Department

Evgeny G. Zykov

Email: edgeki@mail.ru
ORCID iD: 0009-0007-9488-1820
SPIN-code: 6970-0947

Postgraduate of the Technology of Mechanical Engineering Department

Nikolay Yu. Kutergin

Email: nik03071983@yandex.ru
ORCID iD: 0009-0005-7096-9321
SPIN-code: 1065-5919

Postgraduate of the Technology of Mechanical Engineering Department

Dmitry V. Plekhov

Email: WILDERHUND43@yandex.ru
ORCID iD: 0009-0003-1851-2856

Postgraduate of the Technology of Mechanical Engineering Department

Anatoly N. Kartashevich

Email: Kartashevich@yandex.ru
ORCID iD: 0000-0002-3649-1521
SPIN-code: 8541-5330

Dr. Sci. (Engineering), Professor, Head of the Tractors, Vehicles and Machines for Environmental Management Department

References

Supplementary files

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2. Fig. 1. The bench for testing the KI-22210-02M-15 fuel injection equipment.

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3. Fig. 2. Layout of the mixing facility: а — front view; b — section; 1 — a body; 2, 3 — windows of supply of main (diesel) and additional fuel; 4 — a window for multicomponent mixed fuel output; 5 — an auger; 6 — vanes; 7 — a drilled cylinder.

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4. Fig. 3. Scheme of installation of the 3TF-2000DK electric fan and a confuser.

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5. Fig. 4. The Fluke 574 infrared thermometer.

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6. Fig. 5. Full load curve of the high-pressure fuel pump when operating with diesel fuel with heating.

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7. Fig. 6. Full load curve of the high-pressure fuel pump when operating with multicomponent mixed fuel.

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