Test method for anti-coking performance of diesel engine oil for turbochargers

Abstract

This invention discloses a method for testing the anti-coking performance of diesel engine oil in turbochargers. The main design concept of this invention lies in designing a full-process test based on engine operation, including high smoke conditions, low temperature and low load conditions, high temperature and high load conditions, and multiple rounds of cyclic testing to simulate the high and low temperature fluctuations of engine oil. This achieves a comprehensive assessment of the impact of engine oil performance changes on turbocharger coking. Furthermore, engine oil sampling is performed at predetermined stages to monitor relevant physicochemical properties. Further, the turbocharger is disassembled and evaluated after the test procedure, enabling an accurate evaluation of the engine oil's anti-coking performance. This facilitates the matching development of engine oils during engine development and avoids problems such as turbocharger damage and reduced power caused by using unsuitable engine oil. This invention comprehensively covers soot dispersion, high-temperature shear resistance, and temperature oscillation, providing significant guidance for the comprehensive evaluation of engine oil's anti-coking performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile engine, in particular to a diesel engine oil anti-turbocharger coking performance test method. BACKGROUND

[0002] The automobile engine technology is constantly innovating, among which the application of turbocharger is gradually mature and universal. Turbocharging is a technology that uses the heat energy, kinetic energy and pressure energy contained in the high-temperature exhaust gas discharged from the exhaust pipe to make the turbine rotate at high speed and drive the compressor impeller coaxially installed with it. Fresh air is pressurized in the compressor and then enters the cylinder to increase the air density and intake volume. The turbocharger shaft is supported in the intermediate body by two floating bearings, and the engine oil flowing through the oil passage in the intermediate body is used for lubrication and cooling of the turbocharger shaft.

[0003] The rotational speed of the turbocharger shaft reaches hundreds of thousands of revolutions, and the exhaust gas temperature reaches hundreds or even thousands of degrees. If the engine oil performance is not excellent, coking will easily occur at the shaft end and the shell, thereby damaging the performance of the turbocharger and the engine. The turbocharger coking of diesel oil refers to that most diesel engines are equipped with turbochargers to improve the intake volume and power. The mechanical turbocharger bearing is mostly fluid-lubricated. The turbocharger rotates at high speed, and the exhaust gas temperature is high. If the high-temperature shear resistance of the lubricating oil is poor and the oxidation stability is poor, coking problems will easily occur, thereby reducing the performance of the turbocharger and the power of the engine. The anti-turbocharger coking performance of diesel oil refers to that the formulation of the engine oil can inhibit the coking of the engine oil in the turbocharger to a certain extent, such as adjusting the base oil grade, adjusting the content and proportion of related elements in the additive formulation, etc., to improve the high-temperature high-shear performance and oxidation stability of the engine oil, and avoid coking of the engine oil.

[0004] During the development of engine products, a series of tests are generally conducted to investigate the performance and durability of the engine and its key components. The test methods are different for different enterprises. Generally, on the basis of conventional reliability, the test method designed by the enterprise is used for targeted investigation and verification. For example, the existing conventional reliability includes alternating load test, full-speed full-load test and thermal shock test. The test conditions lack pertinence and cannot effectively cover the working conditions of the engine, the extreme working conditions of the turbocharger and the comprehensive use of the engine oil. Therefore, the engine oil specifications matched for the engine and the turbocharger are not suitable, turbocharger coking failures occur in the market, and problems are not exposed in advance during the development and verification process. SUMMARY

[0005] In view of the above, the present application aims to provide a diesel engine oil anti-turbocharger coking performance test method to solve the aforementioned technical problems.

[0006] The technical solution adopted by the present application is as follows:

[0007] The application provides a test method for anti-coking performance of diesel engine oil, which comprises the following steps:

[0008] Step S1: selecting an engine object and filling the engine with oil to be evaluated;

[0009] Step S2: running a preset high-smoke condition;

[0010] Step S3: running a preset low-temperature idling condition;

[0011] Step S4: running a preset high-temperature and high-load condition;

[0012] Step S5: running a preset simulated road driving condition;

[0013] Step S6: repeating the steps S2-S5 as a cycle for several cycles;

[0014] Step S7: recording the engine power, torque, oil pressure, turbocharger inlet pressure and turbocharger outlet pressure during the cycle test, and collecting oil samples and performing physical and chemical detection for a certain number of cycles as a collection period.

[0015] In at least one possible implementation, the step of selecting an engine object and filling the engine with oil to be evaluated comprises the following steps:

[0016] A new engine to be developed is selected, the oil to be evaluated is replaced after a running-in program, and an initial engine performance test is performed after the engine oil temperature sensor and the engine oil pressure sensor are assembled.

[0017] In at least one possible implementation, the test method further comprises the following steps: before the test starts, driving the engine to run in a maximum torque condition and a full-speed full-load condition, adjusting the fixed engine oil cooler cooling flow path pipe diameter and controlling the flow, and controlling the engine outlet water temperature to be 95℃±1℃, and the main oil passage oil temperature to be in the range of 130℃-140℃.

[0018] In at least one possible implementation, the step of running a preset high-smoke condition comprises the following steps: driving the engine to run in a condition corresponding to the maximum value in a preset smoke mapping table, and controlling the engine outlet water temperature to be 88℃±2℃, and the running time to be 2 hours.

[0019] In at least one possible implementation, the step of running a preset low-temperature idling condition comprises the following steps: controlling the engine to run at a predetermined idling speed, and controlling the engine outlet water temperature to be 38℃±2℃, and the running time to be 2 hours.

[0020] In at least one possible implementation, the running of the preset high-temperature high-load working condition comprises: driving the current engine to run in a maximum torque working condition and a full-speed full-load working condition, and controlling the engine water outlet temperature to be 95 DEG C + / - 1 DEG C, and the engine oil temperature to be 130 DEG C-140 DEG C, and sequentially running for 2 hours.

[0021] In at least one possible implementation, the running of the preset simulated road driving working condition comprises: driving the engine to run at 1500 rpm / 60 Nm, and controlling the engine water outlet temperature to be 88 DEG C + / - 2 DEG C, and running for 2 hours.

[0022] In at least one possible implementation, after step S7, the engine performance is retested, and the engine and the supercharger are disassembled for comprehensive evaluation.

[0023] Compared with the prior art, the main design concept of the application has the following advantages:

[0024] (1) The high-smoke working condition is designed, and the influence of the engine oil smoke soot dispersing performance on the supercharger coking is fully evaluated;

[0025] (2) The idle low-temperature low-load working condition is designed, and the influence of the engine oil flowability on the supercharger coking is fully evaluated;

[0026] (3) The high-temperature high-load working condition is designed, and the influence of the engine oil high-temperature shear resistance on the supercharger coking is fully evaluated;

[0027] (4) The test cycle is designed, the high and low oscillation of the engine oil temperature is realized, and the influence of the engine oil performance change on the supercharger coking is fully evaluated.

[0028] The application samples the engine oil at the predetermined link, monitors the related physical and chemical properties of the engine oil, disassembles and evaluates the supercharger after the test procedure, realizes the accurate evaluation of the anti-supercharger coking performance of the engine oil, is beneficial to the matching development of the engine oil in the engine development, avoids the problems of the supercharger damage and power reduction caused by the application of the unsuitable specification engine oil to the engine, especially comprehensively covers the smoke soot dispersing performance, the high-temperature shear resistance, the temperature oscillation and the like, comprehensively evaluates the anti-supercharger coking performance of the engine oil, and plays a significant guiding role. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to make the object, the technical scheme and the advantages of the application more clear, the application will be further described below with reference to the drawings, in which:

[0030] Figure 1 The flowchart of the diesel engine oil anti-supercharger coking performance test method provided by the embodiment of the application is shown. DETAILED DESCRIPTION

[0031] Embodiments of the present application are described below in detail, examples of which are shown in the accompanying drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, and are used for explanation of the present application, and cannot be interpreted as a limitation of the present application.

[0032] An embodiment of a diesel engine oil anti-turbo-coking performance test method is proposed, specifically as shown in Figure 1 , which includes:

[0033] Step S1, select an engine object and fill in the oil to be evaluated;

[0034] In actual operation, a new engine to be developed for test can be selected according to normal design standards, and the break-in is completed according to the conventional break-in specification, the oil to be evaluated is replaced, and oil temperature sensors, oil pressure sensors, etc. are assembled, and initial engine performance tests (including external characteristics, universal characteristics) are carried out. In some preferred embodiments, the engine is preheated before the formal test starts, and is operated at the maximum torque condition and the full speed full load condition, the oil cooler cooling flow path diameter of the fixed engine is adjusted and the flow is controlled, so that the engine water outlet temperature is 95℃±1℃, and the main oil way oil temperature is in the range of 130℃-140℃ at the above two working conditions.

[0035] Step S2, run the preset high smoke condition;

[0036] This condition is the engine condition corresponding to the maximum value in the current engine smoke MAP, and the engine water outlet temperature is controlled to be 88℃±2℃ by using the test bench water constant temperature device, and the oil temperature is free to balance, and the running time is 2 hours.

[0037] Step S3, run the preset low temperature idle condition;

[0038] This condition is that the engine is running at a given idle speed, and the engine water outlet temperature is controlled to be 38℃±2℃ by using the test bench water constant temperature device, and the oil temperature is free to balance, and the running time is 2 hours.

[0039] Step S4, run the preset high temperature high load condition;

[0040] Drive the current engine to run at the maximum torque condition and the full speed full load condition, control the engine water outlet temperature to be 95℃±1℃ by using the test bench water constant temperature device, and the oil temperature is 130℃-140℃, and run for 2 hours in turn.

[0041] Step S5, run the preset simulated road driving condition;

[0042] The working condition is 1500rpm / 60Nm, the engine water temperature is controlled to be 88 DEG C + / -2 DEG C by using a water constant temperature device of a test bench, the oil temperature is free balanced temperature, and the running time is 2 hours.

[0043] Step S6, taking steps S2-S5 as a cycle, repeating execution of several (such as 40) cycles, a total of 400 hours.

[0044] Step S7, recording the engine power, torque, oil pressure, supercharger inlet pressure, supercharger outlet pressure during the cycle test, and taking a certain number of cycles as a collection period, collecting oil samples and performing physical and chemical detection.

[0045] Finally, it can be supplemented that after step S7, the engine performance (including external characteristics, universal characteristics) is retested, and the engine and supercharger are disassembled for comprehensive evaluation.

[0046] To sum up, the main design concept of the application is to design a full-flow test based on engine operation, including high smoke condition, low temperature and low load condition, high temperature and high load condition and multi-cycle test, to simulate the high and low oscillation of oil temperature, and to fully evaluate the influence of engine oil performance change on supercharger coking. And in the predetermined link, the oil sampling is carried out, the related physical and chemical properties of the oil are monitored, further, the test procedure is disassembled and evaluated, the accurate evaluation of the anti-supercharger coking performance of the oil is realized, which is beneficial to the matching development of the oil in the engine development, avoids the problems of supercharger damage, power decline and the like caused by the application of unsuitable specification oil in the engine, the application comprehensively covers the smoke soot dispersibility, high temperature shear resistance, temperature oscillation and the like, and plays a significant guiding role in comprehensively evaluating the anti-supercharger coking performance of the oil.

[0047] In the embodiment of the application, "at least one" means one or more, and "multiple" means two or more. "And / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B, which means that A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it. "At least one of the following" and the like means any combination of these items, including any combination of single or multiple items. For example, at least one of a, b and c can mean: a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b and c can be single or multiple.

[0048] The above detailed description of the structure, features and effects of the present application is based on the embodiments shown in the drawings, but the above is only the preferred embodiment of the present application, and it should be noted that the technical features involved in the above embodiments and preferred modes can be reasonably combined and matched into various equivalent schemes by those skilled in the art without departing from or changing the design idea and technical effects of the present application. Therefore, the present application is not limited to the implementation range shown in the drawings, and any changes or modifications made in accordance with the concept of the present application, or equivalent embodiments with equivalent changes, shall be within the scope of protection of the present application.

Claims

1. A method of testing the anti-junker coking performance of a diesel engine oil, characterized in that, The method comprises the following steps: S1, selecting an engine object and filling the engine oil to be evaluated; S2, running a preset high smoke condition, which comprises: driving the engine to run in a condition corresponding to the maximum value in a preset smoke mapping table, and controlling the engine outlet water temperature to be 88℃±2℃, and running for 2 hours; S3, running a preset low temperature idle condition, which comprises: controlling the engine to run at a predetermined idle speed, and controlling the engine outlet water temperature to be 38℃±2℃, and running for 2 hours; S4, running a preset high temperature and high load condition, which comprises: driving the engine to run in a maximum torque condition and a full speed and full load condition, and controlling the engine outlet water temperature to be 95℃±1℃, and the engine oil temperature to be 130℃-140℃, and running for 2 hours in sequence; S5, running a preset simulated road driving condition, which comprises: driving the engine to run at 1500rpm / 60Nm, and controlling the engine outlet water temperature to be 88℃±2℃, and running for 2 hours; S6, taking steps S2-S5 as a cycle, and repeating the execution of the cycle for several cycles; S7, recording the engine power, torque, oil pressure, supercharger inlet pressure and supercharger outlet pressure during the cycle test, and taking a certain number of cycles as a collection period, collecting the engine oil sample and performing physical and chemical detection.

2. The diesel engine oil anti-turbocharger coking performance test method of claim 1, wherein, The method further comprises the following steps: selecting a new engine to be developed for testing, replacing the engine oil to be evaluated after the running-in program, and assembling an engine oil temperature sensor and an engine oil pressure sensor to perform an initial engine performance test.

3. The diesel engine oil anti-turbocharger coking performance test method of claim 1 wherein, The method further comprises the following steps: before the test starts, driving the engine to run in a maximum torque condition and a full speed and full load condition, adjusting the fixed engine oil cooler cooling flow pipe diameter and controlling the flow, and controlling the engine outlet water temperature to be 95℃±1℃, and the main oil passage oil temperature to be in the range of 130℃-140℃.

4. The diesel engine oil anti-valve gasket deposit performance test method of any of claims 1-3, characterized in that, After step S7, the engine performance is retested, and the engine and the supercharger are disassembled for comprehensive evaluation.

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