A method for predicting the equivalent mileage of valve clearance adjustment

Abstract

The application discloses a valve clearance adjustment equivalent mileage prediction method, comprising the following steps: performing reliability test on an engine; determining the reliability time T of the valve clearance adjustment according to the recorded detection data of the valve before and after the reliability test; obtaining the road spectrum fuel consumption K of the comprehensive working condition through road test, and obtaining the average hourly fuel consumption k of the reliability test recorded by the bench test; calculating the reliability hourly equivalent road spectrum mileage D=k / K*100 through the equal fuel consumption method; obtaining the average engine speed N of the comprehensive working condition through the road test, obtaining the average speed n of the reliability test cycle working condition through the bench test, and calculating the acceleration factor R=n / N; and the equivalent mileage S of the whole vehicle valve clearance adjustment is T*D*R. The application is related to the whole vehicle road test, and effectively evaluates and predicts the adjustment mileage of the whole vehicle valve clearance through equivalent operation and acceleration factor calculation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of engine control, and particularly relates to a valve clearance adjustment equivalent mileage prediction method. BACKGROUND

[0002] The valve train is generally composed of camshaft, rocker shaft, valve rocker, valve spring, valve guide, valve, valve stem oil seal, valve seat ring and other components. Its main function is to open and close the intake and exhaust valves in time according to the working sequence and valve timing of each cylinder of the engine to complete the air exchange process, and to ensure the sealing of the cylinder during the compression stroke and the power stroke. When the engine is working, there is a high temperature condition, and a gap needs to be reserved between the valve and its transmission parts to avoid the thermal expansion of the valve and other parts causing the gap to be too small, the valve to be unable to fully close, and thus affecting the sealing of the cylinder. However, during the long-term operation of the engine, the related components of the valve train will be worn, causing the valve gap to be too large, the valve to open late and close early, the valve opening to be insufficient, the air charge to be insufficient, and the exhaust to be poor, which affects the power of the engine and increases the impact load of the cooperating parts, aggravating the wear of the related components of the valve train. Especially during the use of the vehicle by the user, the valve gap needs to be adjusted to avoid the valve gap being too small or too large, causing abnormal engine performance and customer complaints. Therefore, predicting and evaluating the valve gap adjustment period in the market, setting a reasonable valve gap adjustment period in advance, and reasonably reminding the user to maintain the vehicle can improve the customer satisfaction.

[0003] The current evaluation method for the valve gap adjustment period mainly includes the following: a method and system for evaluating the valve gap adjustment period are disclosed in patent application No. CN201911352191.7. The change range of the valve gap is determined through experiments, and a change model of the valve gap is constructed by data fitting the change of the valve gap with time during the operation of the engine based on the change range. The change model is the change law of the engine during operation. When the current valve gap of the engine meets the change range, no adjustment is needed. When the valve gap does not meet the change range, adjustment is needed. The adjustment period for adjusting the valve gap is determined according to the change law of the valve gap, so that the engine is always in a good operating state and the performance is improved.

[0004] However, the above-mentioned prior art has the following defects: only experimental data are used for adjustment, without considering the actual driving conditions and the influence of the wear mechanism of the valve train on the valve gap mileage, which may lead to inaccurate adjustment period and may result in over-maintenance or insufficient maintenance. The valve gap change in the actual use of the vehicle cannot be accurately predicted, which may adversely affect the performance, fuel consumption, emissions, reliability and service life of the engine, and even cause safety hazards.

[0005] The information disclosed in the background section merely to increase the understanding of the general background of the application and should not be considered as admitting that the information forms prior art that is already known to those of ordinary skill in the art. SUMMARY

[0006] The purpose of the present application is to provide a valve clearance adjustment equivalent mileage prediction method, which is related to vehicle road test, combined with the wear mechanism of valve train, through equivalent operation and acceleration factor calculation, to evaluate and predict the adjustment mileage of vehicle valve clearance, to set a reasonable valve clearance adjustment period in advance, to reasonably remind users to maintain, to improve customer satisfaction, and to improve product competitiveness.

[0007] To achieve the above purpose, the present application adopts the following technical scheme:

[0008] A valve clearance adjustment equivalent mileage prediction method, comprising the following steps:

[0009] S1: Reliability test is performed on the engine, and the reliability time T of valve clearance adjustment is determined according to the recorded detection data of the valve before and after the reliability test;

[0010] S2: The road spectrum fuel consumption K of comprehensive working conditions is obtained through road test, and the reliability test average hourly fuel consumption k is obtained through bench test record, and the reliability hourly equivalent road spectrum mileage D is calculated through the equal fuel consumption method, D=k / K*100;

[0011] S3: The average engine speed N of comprehensive working conditions is obtained through road test, and the average speed n of reliability test cycle working conditions is obtained through bench test, and the acceleration factor R is calculated, R=n / N;

[0012] S4: The reliability time T of valve clearance adjustment, the reliability hourly equivalent road spectrum mileage D and the acceleration factor R are obtained according to the calculation, and the equivalent mileage S of vehicle valve clearance adjustment is obtained, S=T*D*R.

[0013] Specifically, in step S1, the recorded detection data of the valve before and after the reliability test includes:

[0014] The valve clearance a and the valve subsidence b are recorded before the reliability endurance verification test;

[0015] The valve clearance A and the valve subsidence B are detected after the reliability test;

[0016] The maximum valve clearance H which does not affect the normal operation of the engine is verified by test;

[0017] The minimum valve clearance h which does not affect the normal operation of the engine is verified by test;

[0018] The limit valve subsidence amount C allowed by design.

[0019] Specifically, in step S1, the reliability time T of valve clearance adjustment is determined according to the recorded detection data of the valve before and after the reliability test, including: if the valve subsidence amount after reliability exceeds the limit valve subsidence amount allowed by design, that is, B≥C, and the engine performance is normal and passes the reliability verification, the reliability verification time Y is determined as the reliability time T of valve clearance adjustment, that is, T=Y, regardless of whether the valve clearance after reliability exceeds the valve clearance limit value.

[0020] Specifically, in step S1, the reliability time T of valve clearance adjustment is determined according to the recorded detection data of the valve before and after the reliability test, including: if the valve subsidence amount after reliability does not exceed the limit valve subsidence amount allowed by design, that is, B

[0021] Specifically, in step S1, the reliability time T of valve clearance adjustment is determined according to the recorded detection data of the valve before and after the reliability test, including: if the valve subsidence amount after reliability does not exceed the limit valve subsidence amount allowed by design, that is, B

[0022] When the valve subsidence amount reaches the limit valve subsidence amount allowed by design, and the valve clearance is still within the limit value range, the reliability time of valve clearance adjustment is the equivalent time of the valve subsidence amount change amount reaching the limit valve subsidence amount allowed by design, that is, T1=C / B*Y.

[0023] When the valve subsidence amount does not reach the limit valve subsidence amount allowed by design, and the valve clearance reaches the maximum valve clearance, the reliability time of valve clearance adjustment is the equivalent time of the valve clearance reaching the maximum valve clearance, that is, T2=(H-a) / (A-a)*Y.

[0024] When the valve subsidence amount change amount does not reach the limit value, and the valve clearance reaches the minimum valve clearance, the reliability time of valve clearance adjustment is the equivalent time of the valve clearance reaching the minimum valve clearance, that is, T3=(a-h) / (a-A)*Y.

[0025] The reliability time of valve clearance adjustment is T=MIN(T1, T2, T3).

[0026] Compared with the prior art, the present application has the following beneficial effects:

[0027] 1、The technical scheme comprehensively considers reliability test, road test and theoretical calculation, first acquires key data such as valve clearance and valve subsidence amount by simulating long-term operation of the engine through bench test, provides a basis for prediction, secondly introduces the equal fuel consumption method, converts the fuel consumption of the bench test into equivalent road mileage, makes the test result closer to the actual use condition, finally considers the difference between the bench test and the actual road driving, effectively links the bench test result with the actual road driving condition, makes the prediction result more practical, and finally more comprehensively evaluates the change condition of the valve clearance, thereby more accurately predicting the mileage of the vehicle in actual use which needs to be adjusted, avoids excessive maintenance and insufficient maintenance, thereby improving the performance, reliability and durability of the engine, and reducing the maintenance cost.

[0028] 2、The technical scheme simultaneously considers the valve clearance and the valve subsidence amount, more comprehensively evaluates the wear state of the valve mechanism, and improves the reliability of the prediction. Especially for the case that the valve subsidence amount exceeds the limit value, even if the valve clearance is still within the limit value, it is determined that adjustment is needed, which is more in line with the actual use condition, and potential engine failure is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0029] Fig. 1 It is a step schematic diagram of the valve clearance adjustment equivalent mileage prediction method of the application.

[0030] Fig. 2 It is a flow chart of the valve clearance adjustment equivalent mileage prediction method of the application.

[0031] Fig. 3 It is a reliability time judgment logic diagram of the valve clearance adjustment of the application. DETAILED DESCRIPTION

[0032] To describe the technical content, purposes and effects of the application in detail, the following will be described in combination with the embodiments and the accompanying drawings. In the description of the embodiments, it should be understood that the terms indicating the position or positional relationship are based on the position or positional relationship shown in the drawings, and are only for the purpose of describing the embodiments and simplifying the description, and therefore cannot be understood as limiting the application.

[0033] The technical scheme adopted in the embodiments is a valve clearance adjustment equivalent mileage evaluation and prediction method, as shown in Figs. 1-3 The flow chart of Fig. 2 The data required to be collected are as follows:

[0034] 1. Reliability pre-data detection: record the valve clearance a and the valve subsidence amount b before the reliability durability verification test;

[0035] 2. Post-reliability data detection: post-reliability detection of valve clearance A, valve subsidence B;

[0036] 3. Maximum valve clearance: maximum valve clearance H verified by test that does not affect normal operation of the engine;

[0037] 4. Minimum valve clearance: minimum valve clearance h verified by test that does not affect normal operation of the engine;

[0038] 5. Valve subsidence limit: limit of extreme valve subsidence C allowed by design;

[0039] 6. Reliability time for valve clearance adjustment: reliability time T for valve clearance adjustment obtained by comparative analysis and calculation according to post-reliability detection data, valve clearance, and limit of extreme valve subsidence allowed by design;

[0040] 7. Road spectrum fuel consumption per 100 km: road spectrum fuel consumption per 100 km K collected by vehicle road test input;

[0041] 8. Reliability test average hourly fuel consumption: average hourly fuel consumption k of reliability endurance test;

[0042] 9. Road spectrum operating condition average speed: engine average speed N of vehicle road test operating condition;

[0043] 10. Reliability test cycle average speed: engine average speed n of reliability endurance test cycle operating condition;

[0044] 11. Reliability per hour equivalent road spectrum mileage: equivalent road spectrum mileage D corresponding to reliability verification per hour calculated by equal fuel consumption method;

[0045] 12. Acceleration factor: acceleration factor R of road spectrum test corresponding to reliability verification calculated according to road spectrum operating condition average speed and reliability test cycle average speed;

[0046] 13. Vehicle valve clearance adjustment mileage: vehicle valve clearance adjustment mileage S calculated according to reliability time for valve clearance adjustment, reliability per hour equivalent road spectrum mileage calculated by equal fuel consumption method, and acceleration factor.

[0047] Specifically, the evaluation and prediction method of the valve clearance adjustment equivalent mileage of the embodiment specifically includes the following steps:

[0048] S1: performing reliability test on the engine, and determining the reliability time T for valve clearance adjustment according to the recorded detection data of the valve before and after the reliability test.

[0049] Specifically, the recorded detection data of the valve before and after the reliability test includes:

[0050] Considering the sufficiency and effectiveness of the component verification, a suitable durability test time and test durability working condition are set to perform reliability durability verification on the valve train, and the valve clearance a and valve recession b before reliability are recorded to ensure normal test conditions;

[0051] After the reliability test is completed, the valve clearance A and valve recession B are detected and recorded to check the damage of the valve train;

[0052] The bench test verifies that it does not cause abnormal engine performance and does not lead to valve train failure, and there is a certain safety margin for the maximum valve clearance H and the minimum valve clearance h.

[0053] Valve clearance and valve recession are key indicators for evaluating the state of the valve train. Valve clearance refers to the gap between the end of the valve stem and the driving mechanism (such as camshaft or rocker arm) when the valve is closed. Valve recession refers to the amount of indentation caused by the wear or deformation of the valve seat on the cylinder head. Changes in these two parameters directly affect the opening and closing of the valve, and thus affect the performance of the engine. Reasonable limits are set as the basis for adjustment: in order to ensure the normal operation of the engine, the valve clearance and valve recession need to be controlled within a certain range. Therefore, according to the design requirements and test verification, the maximum valve clearance H and the minimum valve clearance h, as well as the allowable limit valve recession C, are set. When the valve clearance or valve recession exceeds these limits, it is considered necessary to adjust.

[0054] According to the recorded test data of the valve before and after reliability, the reliability time T of valve clearance adjustment is determined, and the determination logic is as shown in Fig. 3 , which includes:

[0055] According to the detection data after reliability, if the valve recession after reliability exceeds the allowable limit valve recession, i.e. B≥C, and the engine performance is normal and passes the reliability verification, then regardless of whether the valve clearance after reliability exceeds the valve clearance limit, the reliability verification time Y is set as the reliability time T of valve clearance adjustment, i.e. T=Y;

[0056] Similarly, if the valve recession after reliability does not exceed the allowable limit valve recession, i.e. B

[0057] If the valve recession after reliability is within the range of the allowable limit valve recession requirement, and the valve clearance after reliability is within the limit, i.e. B

[0058] ① Continue to verify the reliability, the valve sinking amount will first reach the design allowed limit valve sinking amount, the valve gap is still within the limit value requirement range, then the reliability time of the valve gap adjustment is the equivalent time of the valve sinking amount change amount reaching the design allowed limit valve sinking amount, that is, T1=C / B*Y;

[0059] ② Continue to verify the reliability, the valve sinking amount does not reach the design allowed limit valve sinking amount, the valve gap reaches the maximum valve gap, then the reliability time of the valve gap adjustment is the equivalent time of the valve gap reaching the maximum valve gap, that is, T2=(H-a) / (A-a)*Y;

[0060] ③ Continue to verify the reliability, the valve sinking amount change amount does not reach the limit value, the valve gap reaches the minimum valve gap, then the reliability time of the valve gap adjustment is the equivalent time of the valve gap reaching the minimum valve gap, that is, T3=(a-h) / (a-A)*Y;

[0061] Therefore, in this type, the reliability time of the valve gap adjustment is the shortest time among the three cases, that is, T=MIN(T1,T2,T3).

[0062] Compared with the prior art which simply uses test time as adjustment period, the method more accurately determines the adjustment time according to the change of the valve gap and the valve sinking amount, and in combination with the limit value requirement, and is more in line with the actual wear state. Especially for the case that the valve sinking amount and the valve gap do not reach the limit at the same time, the minimum value is calculated respectively, so that the prediction is more comprehensive.

[0063] S2: Obtain the road spectrum fuel consumption K of the comprehensive working condition through road test, and obtain the reliability test average hourly fuel consumption k of the bench test record, and calculate the reliability hourly equivalent road spectrum mileage D=k / K*100 through the equal fuel consumption method.

[0064] This step relates the bench test results to the actual road driving conditions, and converts the fuel consumption of the bench test into equivalent road driving mileage through the equal fuel consumption method, so that the results of the bench test are more practical, easier to understand and apply, and compared with directly using the bench test time to predict the adjustment mileage, the introduction of the equal fuel consumption method improves the accuracy of the prediction.

[0065] S6: Obtain the engine average speed N of the comprehensive working condition through road test, which can be monitored by ECU and averaged, obtain the average speed n of the reliability test cycle working condition through bench test, consider the influence of speed impact on the wear of the valve train, and calculate the acceleration factor R=n / N.

[0066] By comparing the average engine speed of the bench test and the road test, the bench test's accelerated wear effect on the valve train can be evaluated. This step quantifies the severity of the bench test relative to actual road driving, and compared to simply using test time for equivalence, the introduction of an acceleration factor accounts for the impact of speed spikes on valve train wear, improving the accuracy of the prediction.

[0067] S7: Based on the reliability time T, the reliability equivalent road spectrum mileage D and the acceleration factor R calculated according to the previous steps, the vehicle valve clearance adjustment mileage S = T * D * R is further calculated, and the vehicle valve clearance adjustment mileage S is taken as the valve clearance adjustment equivalent mileage.

[0068] Although the present application has been described in detail with specific reference to the embodiments, it is obvious that modifications or improvements can be made to the present application on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present application are within the scope of the present application.

Claims

1. A method of predicting valve clearance adjustment equivalent mileage, characterized by, The method comprises the following steps: S1: performing a reliability test on the engine, and determining a reliability time T of valve clearance adjustment according to recorded detection data of the valve before and after the reliability test; S2: obtaining a road fuel consumption K of a comprehensive working condition through a road test, and obtaining an average hourly fuel consumption k of the reliability test recorded by a bench test, and calculating a reliability equivalent road mileage per hour D=k / K*100 through an equal fuel consumption method; S3: obtaining an average engine speed N of the comprehensive working condition through the road test, obtaining an average speed n of the reliability test cycle working condition through the bench test, and calculating an acceleration factor R=n / N; S4: obtaining an equivalent mileage S of the valve clearance adjustment of the whole vehicle according to the reliability time T of the valve clearance adjustment, the reliability equivalent road mileage per hour D, and the acceleration factor R. In step S1, the recorded detection data of the valve before and after the reliability test comprises: a valve clearance a and a valve subsidence b recorded before the reliability endurance verification test; a valve clearance A and a valve subsidence B detected after the reliability test; a maximum valve clearance H that does not affect the normal operation of the engine verified by the test; a minimum valve clearance h that does not affect the normal operation of the engine verified by the test; a limit valve subsidence C allowed by design; In step S1, the reliability time T of the valve clearance adjustment is determined according to the recorded detection data of the valve before and after the reliability test, comprising: if the valve subsidence after the reliability test exceeds the limit valve subsidence allowed by design, i.e. B≥C, and the engine performance is normal and passes the reliability verification, the reliability verification time Y is determined as the reliability time T of the valve clearance adjustment, i.e. T=Y, regardless of whether the valve clearance after the reliability test exceeds the valve clearance limit value or not. In step S1, the reliability time T of the valve clearance adjustment is determined according to the recorded detection data of the valve before and after the reliability test, comprising: if the valve subsidence after the reliability test does not exceed the limit valve subsidence allowed by design, i.e. B In step S1, the reliability time T of the valve clearance adjustment is determined according to the recorded detection data of the valve before and after the reliability test, comprising: if the valve subsidence after the reliability test is within the range of the limit valve subsidence allowed by design, and the valve clearance after the reliability test is within the limit value, i.e. B when the valve subsidence reaches the limit valve subsidence allowed by design, and the valve clearance is still within the range of the limit value, the reliability time T of the valve clearance adjustment is the equivalent time of the valve subsidence change amount reaching the limit valve subsidence allowed by design, i.e. T1=C / B*Y; when the valve subsidence does not reach the limit valve subsidence allowed by design, and the valve clearance reaches the maximum valve clearance, the reliability time T of the valve clearance adjustment is the equivalent time of the valve clearance reaching the maximum valve clearance, i.e. T2=(H-a) / (A-a)*Y; When the valve sinking amount change amount does not reach the limit value, and the valve clearance reaches the minimum valve clearance, the reliability time of the valve clearance adjustment is the equivalent time of the valve clearance reaching the minimum valve clearance, that is, T3=(a-h) / (a-A)*Y; The reliability time of the valve clearance adjustment is T=MIN(T1, T2, T3).

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