A diesel engine oil dilution quick verification method

Abstract

The application discloses a diesel engine oil dilution rapid verification method, comprising the following steps: S1, data acquisition; S2, arranging the engine to be verified on a test bench; S3, confirming the performance of the engine to be verified; S4, determining the weight of the engine oil before verification; S5, recording test bench test data; S6, statistically analyzing the test data, and analyzing the oil sump engine oil weight, engine oil viscosity and fuel dilution change in an oil change cycle; S7, according to the analysis result of step S6, if the engine oil viscosity and fuel dilution change exceed the technical index value, the DPF regeneration control strategy needs to be optimized, and steps S2-S6 are repeated until the engine oil viscosity and fuel dilution change are within the technical index range. The application simulates the actual use scene of the engine to be verified on the test bench, improves the test bench verification accuracy, and has the advantages of avoiding engine oil dilution and the like.

Description

Technical Field

[0001] This invention relates to the field of vehicle control technology, and in particular to a rapid verification method for diesel engine oil dilution. Background Technology

[0002] To meet increasingly stringent emission requirements, vehicles and engines need to incorporate aftertreatment systems. Companies typically have two technical options: EGR+DOC+DPF and DOC+DPF+SCR. DPF, also known as a diesel particulate filter regenerator, is a device that uses alternating blockage of the inlet and outlet of a carrier pore to force airflow through a porous wall, thereby reducing particulate matter (PM) emissions in exhaust. After passing through the DOC, exhaust particles are filtered by the DPF channel walls through diffusion, deposition, adsorption, and interception. As the diesel engine's operating time increases, the DPF captures more and more particles, eventually posing a risk of blockage. This can cause an increase in back pressure in the vehicle's exhaust system, leading to a deterioration in the vehicle's power and fuel economy. Therefore, once the DPF has captured a certain amount of particles, it needs to remove them. This process is called DPF regeneration, and regeneration methods include active regeneration (high regeneration temperature) and passive regeneration (low regeneration temperature).

[0003] Currently, high-pressure common rail diesel engines use in-cylinder post-injection for active / passive regeneration. Fuel is injected far from top dead center, and some unvaporized post-injected fuel remains on the cylinder wall, flowing down into the oil pan. This causes an increase in oil level (rising oil level) and a decrease in oil pressure. This phenomenon, where diesel fuel enters the oil and causes an increase in oil level in the oil pan, is commonly referred to as "oil dilution." Numerous tests have shown that an oil dilution rate exceeding 7% significantly reduces oil viscosity, leading to poor lubrication of engine moving parts and other malfunctions. Typically, manufacturers conduct testing during development to ensure an oil dilution rate of less than 7% within an oil change cycle. However, due to the simplistic bench testing methods and significant differences between testing conditions and actual user operating conditions, some products still exhibit oil dilution rates exceeding the target value after being released to the market.

[0004] Typically, companies conduct routine reliability tests (rated power reliability or thermal shock reliability) on a test bench. During the test, engine oil samples are taken periodically and sent to a professional organization to test the oil dilution. The drawbacks of this method are: the boundaries of rated power reliability or thermal shock reliability differ significantly from actual market loads; the boundaries of cyclic fuel injection volume, engine coolant temperature, oil temperature, and air temperature also differ considerably, resulting in unsatisfactory verification results.

[0005] Existing patent document CN109630231B discloses a solution and apparatus for oil dilution, which regulates the oil temperature through a thermostat, thereby evaporating fuel mixed in the oil, reducing the risk of oil dilution, extending the oil's service life, and protecting the engine. This existing patent document differs from the technical approach used in this application to solve the problem of oil dilution.

[0006] The above background information is provided only to aid in understanding the concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0007] The purpose of this invention is to propose a rapid verification method for oil dilution that simulates actual end-customer usage scenarios during the research and development phase to assess whether existing DPF regeneration strategies pose any risks.

[0008] Therefore, this invention proposes a rapid verification method for diesel engine oil dilution.

[0009] Preferably, the present invention may also have the following technical features:

[0010] A rapid verification method for diesel engine oil dilution includes the following steps:

[0011] S1. Data Acquisition: Collect the actual typical operating load spectrum of the engine to be verified in different market segments; extract the performance parameters from the actual typical operating load spectrum and convert them into engine bench verification conditions;

[0012] S2. Arrange the engine to be verified on the test bench: Simulate the working conditions of the engine to be verified in actual operation on the test bench according to the actual typical operating load spectrum, and simulate the arrangement of the vehicle accessories of the engine to be verified in actual operation.

[0013] S3. Confirm the performance of the engine to be verified: Add new engine oil that meets the technical specifications to the designated level in the oil pan, start the engine, and verify the performance.

[0014] S4. Determine the oil weight before verification: Stop the machine, drain the oil from the oil pan, weigh the drained oil, and refill the oil pan.

[0015] S5. Record bench test data: Start the engine and perform a durability test according to the actual typical working load spectrum described in step S1. Record the performance parameters during the test, including speed, torque, water temperature, air temperature, oil temperature, pressure, cyclic fuel injection quantity, and remote and rear fuel injection quantity.

[0016] S6. Perform statistical analysis on the test data, and analyze the changes in oil weight, oil viscosity, and fuel dilution in the oil pan during an oil change cycle.

[0017] S7. Based on the analysis results of step S6, if the changes in engine oil viscosity and fuel dilution exceed the technical specifications, the DPF regeneration control strategy needs to be optimized, and steps S2 to S6 are repeated until the changes in engine oil viscosity and fuel dilution are within the technical specifications.

[0018] Furthermore, in step S1, the performance parameters include engine speed, torque, water temperature, air temperature, oil temperature, pressure, circulating fuel injection quantity, and remote and rear fuel injection quantity.

[0019] Further, in step S2, an engine of the same model as in step S1 is selected for bench testing. The accessories of the engine to be tested are arranged on the bench with reference to the arrangement of vehicle accessories in actual operation. The accessories include oil circuit, water circuit, air circuit and electrical circuit.

[0020] Furthermore, in step S3, the test results of the bench performance-related parameters are in accordance with the requirement that the error between them and the vehicle performance-related parameters in step S1 is no more than 3%; if the performance test results exceed the error range, the performance of the engine to be verified needs to be optimized and adjusted; if the performance test results are within the error range, then step S4 is performed.

[0021] Furthermore, in step S4, the temperature of the oil to be discharged is controlled to be 90°C.

[0022] Furthermore, in step S5, the total duration of a single durability test cycle is set to 500 hours. During the test, the machine is stopped every 50 hours, and the oil is drained and weighed when it is at 90°C. The change in oil weight relative to the oil in step S4 is calculated, and a 50mL oil sample is taken to test the kinematic viscosity of the oil and the fuel dilution rate.

[0023] Furthermore, if the oil viscosity change rate exceeds 20% or the fuel dilution rate exceeds 7% in the analysis results, the DPF regeneration control strategy can be optimized by adjusting the throttle opening or the amount of fuel injected.

[0024] The beneficial effects of this invention compared to existing technologies include: By simulating the operating conditions of the engine under test and the arrangement of vehicle accessories in actual operation, this application can maximize the simulation of real-world vehicle usage scenarios, making bench tests closer to actual operating conditions and improving verification accuracy. By simulating actual user scenarios during the R&D phase, the risks of existing DPF regeneration strategies can be assessed. If risks are found, the DPF regeneration strategy can be adjusted and optimized until the test verification is passed. This can avoid malfunctions after mass production and market launch, save after-sales maintenance costs, and improve customer satisfaction. Attached Figure Description

[0025] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to specific embodiments and the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope or application of the present invention.

[0027] Non-limiting and non-exclusive embodiments will be described with reference to the following figures, wherein the same reference numerals denote the same parts unless otherwise specifically stated.

[0028] like Figure 1 The method for rapid verification of diesel engine oil dilution, as shown, includes the following steps:

[0029] S1. Data Acquisition: Collect actual typical operating load spectra of the engine to be verified in different market segments (such as forklifts, aerial work platforms, harvesters, etc.); extract the performance parameters from the actual typical operating load spectra and convert them into engine bench verification conditions. In this step, the performance parameters include engine speed, torque, water temperature, air temperature, and oil temperature.

[0030] S2. The engine to be tested is placed on a test bench: Based on the actual typical operating load spectrum, the working conditions of the engine to be tested in actual operation are simulated on the test bench, and the arrangement of vehicle accessories in actual operation is also simulated. In this step, the same model of engine as in step S1 is selected for the test bench test. The accessories of the engine to be tested are placed on the test bench with reference to the arrangement of vehicle accessories in actual operation; the accessories include oil lines, water lines, air lines, and electrical lines. Generally, the conventional test bench piping connection method differs from the vehicle piping connection method. This application, by referencing the vehicle piping connection method on the test bench, can maximize the simulation of real-world vehicle usage scenarios, making the test bench test closer to actual operating conditions and improving the verification accuracy.

[0031] S3. Confirm the performance of the engine to be verified: Add new engine oil that meets the technical specifications to the oil pan up to the upper mark on the dipstick, start the engine, and verify the performance. The test results of the bench performance parameters should not have an error of more than 3% compared with the vehicle performance parameters in step S1. If the performance test results exceed the error range, the performance of the engine to be verified needs to be optimized and adjusted; if the performance test results are within the error range, proceed to step S4.

[0032] S4. Determine the oil weight before verification: Stop the engine and drain the oil from the oil pan (record the draining time and temperature; a draining temperature of 90°C and a draining time of 60 minutes are recommended). Weigh the drained oil (G0) and add it back to the oil pan. In this step, the temperature of the oil to be drained is controlled at 90°C. Accurately weighing the oil is crucial, as the viscosity of oil increases and its fluidity decreases at lower temperatures. 90°C is a relatively stable temperature for most engines during normal operation. At this temperature, the oil can be drained completely in a relatively short time, ensuring accurate oil weight before verification and further improving verification accuracy. This embodiment designs the draining temperature at 90°C and the draining time at 60 minutes based on the amount of oil added, ensuring that the oil is completely drained.

[0033] S5. Record bench test data: Start the engine and conduct a durability test according to the actual typical operating load spectrum described in step S1. Record parameters such as engine speed, torque, water temperature, air temperature, oil temperature, pressure, cyclic fuel injection quantity, and long-range fuel injection quantity during the test. Preferably, the total duration of the durability test is set to 500 hours. During the test, the engine is stopped every 50 hours. When the engine oil is at 90°C, the oil is drained and weighed. The change in oil weight relative to the oil weight in step S4 is calculated, and a 50mL oil sample is taken to test the kinematic viscosity of the oil and the fuel dilution rate.

[0034] S6. Perform statistical analysis on the test data, and analyze the changes in oil weight, oil viscosity, and fuel dilution in the oil pan within one oil change cycle (500h).

[0035] S7. Based on the analysis results of step S6, if the changes in engine oil viscosity and fuel dilution exceed the technical specifications, the DPF regeneration control strategy needs to be optimized. Steps S2 to S6 are then repeated until the changes in engine oil viscosity and fuel dilution are within the technical specifications. More specifically, if the engine oil viscosity change rate exceeds 20% or the fuel dilution rate exceeds 7%, the DPF regeneration control strategy is optimized by adjusting the throttle opening or the post-injection quantity.

[0036] Those skilled in the art will recognize that numerous variations are possible with respect to the above description, and the embodiments and figures are merely for describing one or more specific implementations.

[0037] Although exemplary embodiments of the invention have been described and illustrated, those skilled in the art will understand that various changes and substitutions can be made thereto without departing from the spirit of the invention. Furthermore, many modifications can be made to adapt specific situations to the doctrine of the invention without departing from the central concepts of the invention described herein. Therefore, the invention is not limited to the specific embodiments disclosed herein, but may include all embodiments and equivalents that fall within the scope of the invention.

Claims

1. A method of diesel engine oil dilution rapid verification, characterized by: The method comprises the following steps: S1, data collection: collecting actual typical operation load spectrum of the engine to be verified in different market segments; extracting performance parameters in the actual typical operation load spectrum and converting them into engine bench verification working conditions; S2, arranging the engine to be verified on the bench: simulating the working conditions of the engine to be verified in actual operation on the bench according to the actual typical operation load spectrum, and simulating the arrangement mode of the vehicle accessories of the engine to be verified in actual operation; selecting an engine of the same model as that in step S1 to perform bench test, and arranging the accessories of the engine to be verified on the bench according to the arrangement mode of the vehicle accessories of the engine to be verified in actual operation; the accessories include oil circuit, water circuit, gas circuit and electric circuit; S3, confirming the performance of the engine to be verified: adding new engine oil of a grade meeting the technical index requirement to a specified position of the oil pan, starting the engine, and performing performance confirmation; S4, determining the weight of the engine oil before verification: stopping the engine, discharging the engine oil in the oil pan, weighing the discharged engine oil and re-adding the engine oil to the oil pan; in step S4, the temperature of the engine oil to be discharged is controlled to be 90 DEG C; 90 DEG C is a relatively stable temperature when most engines are normally operated, at which the engine oil can be completely discharged in a relatively short time, so that the weight of the engine oil before verification is accurate and the verification accuracy is further improved; S5, recording bench test data: starting the engine, performing endurance test according to the actual typical operation load spectrum described in step S1, and recording performance parameters in the test process; the total duration of one cycle of endurance test is set to be 500 h, the engine is stopped once every 50 h during the test, the engine oil is discharged and weighed when the engine oil is at 90 DEG C, the change amount of the weight of the engine oil relative to the engine oil weight in step S4 is calculated, and 50 mL of engine oil sample is taken to detect the engine oil kinematic viscosity and fuel dilution rate; S6, statistically analyzing the test data to analyze the changes of the weight of the engine oil in the oil pan, the engine oil viscosity and the fuel dilution in one oil change cycle; S7, according to the analysis result in step S6, if the changes of the engine oil viscosity and the fuel dilution exceed the technical index value, the DPF regeneration control strategy needs to be optimized, and steps S2 to S6 are repeated until the changes of the engine oil viscosity and the fuel dilution are within the technical index range.

2. A diesel engine oil dilution quick verification method as set forth in claim 1 characterized by: In step S1, the performance parameters include the engine speed, torque, water temperature, gas temperature, oil temperature, pressure, cycle fuel injection amount and post-injection fuel injection amount.

3. A method of rapid verification of diesel engine oil dilution according to claim 1, characterized in that: In step S3, the test result of the bench performance related parameters is within 3% of the error of the vehicle performance related parameters in step S1, which meets the requirement; if the performance test result exceeds the error range, the performance of the engine to be verified needs to be optimized and adjusted; if the performance test result meets the error range, step S4 is performed.

4. A method of rapid verification of diesel engine oil dilution according to claim 1, characterized in that: if the analysis result of the engine oil viscosity change rate exceeds 20% or the fuel dilution rate exceeds 7%, the DPF regeneration control strategy is optimized by adjusting the throttle opening or adjusting the post-injection fuel injection amount.

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