Method for assessing pumpability of diesel fuels in fuel supply system of internal combustion engines

Abstract

FIELD: internal combustion engines.SUBSTANCE: invention relates to evaluation of the performance properties of diesel fuels in laboratory installations and can be used in testing units and assemblies of fuel equipment for internal combustion engines. The essence of the method consists in assessing the pumpability of diesel fuels in the fuel supply system of internal combustion engines when the temperature of the test fuel is reduced to the pour point. Diesel fuel is maintained at the pour point for 120 minutes, after which a portion of the fuel is pumped through the test circuit at a fuel pump speed of 100 min-1. The pumpability of diesel fuel is assessed based on the temperature at which the time delay in pumping the fuel after turning on the fuel pump is no more than 15 seconds.EFFECT: increasing the efficiency and reliability of test results when assessing the pumpability of diesel fuels in a laboratory setup by creating operating conditions for the fuel system of a diesel internal combustion engine at low temperatures and, in particular, when starting a cold diesel engine and warming it up, with lower labor costs due to the elimination of conducting motor tests as part of transport equipment.1 cl, 1 tbl

Description

[0001] The invention relates to the evaluation of the operational properties of diesel fuels in laboratory installations and can be used in testing units and assemblies of fuel equipment of internal combustion engines (ICE).

[0002] Pumpability is an operational property of diesel fuels, characterizing the pumping of fuels through pipelines, filters, filter-separators, holes and gaps (1 - N.N. Grishin, V.V. Sereda. Encyclopedia of chemmotology. - M .: Pero Publishing House, 2016, p. 499).

[0003] The greatest difficulties when pumping diesel fuel arise at low temperatures. Under these conditions, fuel viscosity increases significantly, and a solid paraffin fraction forms in the fuel. This leads to poor fuel flow through the low-pressure circuit of the diesel engine fuel supply system and a reduction in the standard fuel supply to the high-pressure fuel pump (HPFP). This reduces the performance of the fuel pump, increases the pressure drop across the fuel filters, and reduces the fuel pressure at the outlet of the low-pressure circuit.

[0004] It should be noted that when an internal combustion engine is running at low ambient temperatures, the fuel in some components of the fuel delivery system is partially heated by heat from the warm diesel engine. Furthermore, the fuel is additionally heated by excess fuel drained from the diesel fuel injection pump and injectors. Excess fuel from warmed-up fuel pumps and injectors in various internal combustion engines drains in two ways: either to the fuel pump (in which case the fuel circulates in the pulmonary circuit) or to the fuel tank (in which case the fuel circulates in the system in the primary circuit), thereby partially heating the fuel. As a result, the fuel becomes less viscous, and the paraffin fraction of the fuel liquefies.

[0005] Thus, the deterioration of the pumpability of diesel fuels through the low-pressure circuit of the fuel supply system manifests itself at low temperatures and, especially, when starting a cold engine and warming it up at low idle speeds to a coolant temperature in the internal combustion engine cooling system of 40-50°C.

[0006] The authors were tasked with developing a method that would allow for the rapid and reliable evaluation of the pumpability of diesel fuels at low temperatures in a laboratory setup simulating the low-pressure circuit of a diesel engine fuel supply system [2 - Russian Federation Patent 2843821, G01M 15 / 00, G01N 33 / 22].

[0007] When reviewing sources of patent and scientific research information, technical developments were identified that partially solve the problem. Thus, a method is known for assessing the pumpability of diesel fuels at low temperatures, which includes feeding fuel cooled to a specified temperature through a fine filter for a specified period of time, recording the fuel flow after the fine filter and the pressure drop on the fine filter and assessing the pumpability based on the temperature at which, after 20 minutes of pump operation, the fuel supply required for engine operation in a given mode, equal to 0.4 l / min, is not ensured. [3 - Thematic review. Improving the low-temperature properties of diesel fuels. - M .: TsNIITENefteKhim, 1980, p. 15].

[0008] The disadvantage of this method for assessing the pumpability of diesel fuels is the unreliability of the results obtained, since it does not simulate the actual operating conditions of motor vehicles and tractors at sub-zero temperatures.

[0009] The closest in technical essence and taken as a prototype is a method for assessing the pumpability of diesel fuels at low temperatures, including the sequential pumping of portions of the tested diesel fuel for a given period of time along a test circuit using a fuel pump through a fine filter included in the test circuit simulating the low-pressure fuel system of internal combustion engines, changing the test temperature of each subsequent portion, and subsequent assessment of the pumpability of diesel fuel with a temperature at which, during a given period of time, the current fuel consumption will decrease to the limit value at which the engine stops idling, and the pressure drop across the fine filter corresponding to the critical feed temperature is taken as the critical pressure drop [4 - Russian Federation Patent 2263308, G01N 33 / 22 - prototype].

[0010] A disadvantage of this method for pumping diesel fuels at low temperatures is the significant time required to obtain test results. Furthermore, it should be noted that the known method does not fully simulate the operating conditions of a diesel engine fuel system at sub-zero temperatures.

[0011] The technical result of the invention is an increase in the efficiency and reliability of test results when assessing the pumpability of diesel fuels in a laboratory setup by creating operating conditions for the fuel system of a diesel internal combustion engine at low temperatures and, in particular, when starting a cold diesel engine and warming it up, with less labor costs due to the elimination of conducting motor tests as part of transport equipment.

[0012] The specified technical result is achieved in that in the method for assessing the pumpability of diesel fuels in the fuel supply system of internal combustion engines, including sequential pumping through a test circuit simulating the operation of a low-pressure fuel system of internal combustion engines of portions of the test diesel fuel through a fine filter included in the circuit using a fuel pump at different values ​​​​of the test temperature of each subsequent portion and assessing the pumpability of the diesel fuel based on the value of the information indicator, according to the invention, that the first portion of the test diesel fuel after pouring into the test circuit is cooled to the pouring temperature, this portion of the fuel is maintained at the pouring temperature for 120 minutes, pumping of the portion of the fuel through the test circuit is carried out at a rotation frequency of the rotor of the fuel pump of 100 min -1, the temperature of subsequent portions is reduced relative to the temperature of the previous portion by no more than 2°C, and the minimum temperature in the period from the moment the fuel pump is turned on until the start of pumping, the duration of which is set to no more than 15 seconds, is taken as the pumpability indicator of the tested diesel fuel.

[0013] The method for assessing the pumpability of diesel fuels in the fuel supply system of internal combustion engines is implemented as follows.

[0014] To evaluate the pumpability of diesel fuels in the fuel supply system, a laboratory setup [2] is used, equipped with a test circuit containing a fine fuel filter and a rotary fuel pump with an electric drive, and simulating the operation of the low-pressure fuel system of diesel internal combustion engines, as well as sensors and measuring equipment. The tested diesel fuel in the amount of 100 dm 3The fuel is poured into the test circuit's fuel tank, cooled statically to the pour point, and held at this temperature for 120 minutes. The fuel is then pumped through the test circuit at a fuel pump rotor speed of 100 rpm. -1 , which corresponds to the starting speed for a cold diesel engine. Subsequent portions are lowered relative to the temperature of the previous portion by no more than 2°C. Fuel pumping through the test circuit of the setup should begin no more than 15 seconds after the fuel pump is started.

[0015] The time of 15 seconds is limited by the technical requirements for the starting qualities of engines, according to which the duration of starting a cold diesel engine should not exceed 15 seconds [5 - GOST R 54120-2010. Automotive engines. Starting qualities. Technical requirements].

[0016] The evaluation indicator of the method for assessing the pumpability of diesel fuels in the fuel supply system of internal combustion engines is the minimum temperature in the period from the moment the fuel pump is turned on until the start of pumping, the duration of which is set to no more than 15 seconds, based on the requirements of GOST R 54120-2010.

[0017] Example. The tested diesel fuel is EURO according to GOST 52368-2005, grade C (cloud point minus 6°C, cold filter plugging point minus 8°C, pour point minus 16°C).

[0018] The results of the tests are presented in Table 1.

[0019]

[0020] Analysis of the data in Table 1 shows that at the pour point of the tested diesel fuel sample of minus 16°C, there is no delay in fuel pumpability. When the temperature of the diesel fuel sample dropped to minus 19°C, the delay in fuel pumpability was 12 seconds, which complies with the requirements of GOST R 54120-2010. As the diesel fuel temperature further decreased, fuel pumpability through the test circuit ceased. The minimum temperature at which diesel fuel pumpability occurs was taken as minus 19°C.

[0021] The data in Table 1 confirm the correctness of the selected evaluation indicator - the minimum temperature at which the time delay in pumping fuel after turning on the fuel pump is no more than 15 seconds, as well as the test conditions, which makes it possible to quickly and reliably determine the minimum pumping temperature of diesel fuel.

[0022] Thus, the use of the invention allows not only to reliably evaluate the pumpability of diesel fuels in the fuel supply system of internal combustion engines, but also to do so quickly and with a shorter duration, since the prototype is given a cloud point, which is always higher than the freezing point (according to the invention), and with less labor costs, since it is excluded from conducting motor tests as part of transport equipment (according to the prototype).

Claims

A method for assessing the pumpability of diesel fuels in the fuel supply system of internal combustion engines, including sequential pumping through a test circuit simulating the operation of a low-pressure fuel system of internal combustion engines of portions of the test diesel fuel through a fine filter included in the circuit using a fuel pump at different test temperature values ​​​​for each subsequent portion and assessing the pumpability of the diesel fuel based on the value of the information indicator, characterized in that the first portion of the test diesel fuel after pouring into the test circuit is cooled to the pour point, this portion of the fuel is maintained at the pour point for 120 minutes, pumping of the portion of the fuel through the test circuit is carried out at a rotation frequency of the rotor of the fuel pump of 100 min -1, the temperature of subsequent portions is reduced relative to the temperature of the previous portion by no more than 2°C, and the minimum temperature in the period from the moment the fuel pump is turned on until the start of pumping, the duration of which is set to no more than 15 seconds, is taken as the pumpability indicator of the tested diesel fuel.

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