A method and device for simulating abnormal fresh air intake of a diesel engine

Abstract

The present invention discloses a method for simulating abnormal fresh air intake of a diesel engine, comprising: cutting off a gear shaft connected to a valve plate; adjusting the opening of a TVA valve; measuring an actual value of the fresh air intake of the engine; and comparing the actual value with a model value of the fresh air intake. The present invention also discloses a device for simulating abnormal fresh air intake of a diesel engine. The above method for simulating abnormal fresh air intake of a diesel engine can simulate abnormal fresh air intake by cutting and cutting off a gear shaft connected to a valve plate, and thus will not report related faults of TVA jamming, and is of great significance for studying fault reporting.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a method for simulating the abnormality of fresh air intake of a diesel engine, and also to a device for simulating the abnormality of fresh air intake of a diesel engine. Background Art

[0002] At present, heavy-duty diesel engines need to meet increasingly stringent emission and fuel economy requirements. They often use EGR systems and TVA strategies to make the two work together to correct and adjust the intake volume. When the TVA valve functions normally, the opening will be adjusted according to the engine's operating conditions so that the fresh intake volume under different operating conditions is equal to the required value. When the TVA valve fails and causes abnormal fresh intake volume, the engine OBD system should detect the fault and store it in the ECU. The ECU protects the engine by limiting the torque and speed of the engine, and prompts the driver through the alarm light.

[0003] At the National Testing and Certification Center, TVA fault simulation is required to confirm that when certain TVA faults occur, the fresh air intake volume will be abnormal and the OBD system can report related errors. At this time, the TVA needs to be improved so that it cannot be used normally, so as to achieve error reporting. The setting of the TVA fault part needs to neither report related faults of jamming nor simulate the situation of abnormal fresh air intake volume.

[0004] Therefore, how to provide a method for simulating the abnormal fresh air intake of a diesel engine without reporting related faults of sticking and being able to simulate the abnormal fresh air intake is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] The purpose of the present invention is to provide a method for simulating the abnormal fresh air intake of a diesel engine. By cutting and truncating the gear shaft connected to the valve plate, the TVA stuck related fault will not be reported, and the abnormal fresh air intake can be simulated, which is of great significance for studying fault reporting. Another purpose of the present invention is to provide a device for simulating the abnormal fresh air intake of a diesel engine.

[0006] To achieve the above object, the present invention provides a method for simulating abnormal fresh air intake of a diesel engine, comprising:

[0007] Cut off the gear shaft connected to the valve plate;

[0008] Adjust the opening of the TVA valve;

[0009] Measure the actual value of the fresh air intake of the engine;

[0010] The actual value is compared with a model value of the fresh air intake amount.

[0011] Preferably, the step of measuring the actual value of the fresh air intake amount of the engine specifically includes:

[0012] The rotation speed of the engine is adjusted, and the actual value of the fresh air intake amount of the engine is measured.

[0013] Preferably, the opening ranges from 0° to 85°.

[0014] Preferably, when the opening is 30°, the rotation speed ranges from 800 to 1900 rpm.

[0015] Preferably, after the step of comparing the actual value with the model value of the fresh intake air amount, the method further comprises:

[0016] When the actual value is higher or lower than the model value, a fault is reported.

[0017] The present invention also provides a device for simulating the abnormal fresh air intake of a diesel engine, which uses the above-mentioned method for simulating the abnormal fresh air intake of a diesel engine, including a TVA valve connected to the front end of the engine, the TVA valve is provided with a gear shaft and a valve plate, and the gear shaft connected to the upper end of the valve plate is cut and truncated.

[0018] Preferably, an intake flow sensor for measuring real-time intake flow is provided at the front end of the TVA valve.

[0019] Compared with the above background technology, the method for simulating the abnormal fresh air intake of a diesel engine provided by the present invention includes four steps. First, the gear shaft connected to the valve plate is cut so that the gear shaft connected to the valve plate is cut off; then, the TVA valve is adjusted to change the opening of the TVA valve; then, the actual value of the fresh air intake entering the engine is measured; finally, the measured actual value is compared with the model value of the fresh air intake given in advance. The method for simulating the abnormal fresh air intake of a diesel engine cuts the gear shaft so that the gear shaft and the valve plate are no longer connected. The valve plate is no longer controlled by the drive motor and can be adjusted freely. By freely adjusting the opening of the TVA valve, the fresh air intake can achieve an ideal error reporting effect, and indirectly, the ratio of the actual value of the fresh air intake to the valve opening can be obtained. It will not report the related faults of TVA jamming, but can also simulate the abnormal fresh air intake, which is of great significance for studying fault reporting. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0021] Figure 1 Flow chart of the method for simulating abnormal fresh air intake of a diesel engine provided by an embodiment of the present invention;

[0022] Figure 2 Schematic diagram of the intake and exhaust system;

[0023] Figure 3 Assembly drawing of a normal TVA valve in the prior art;

[0024] Figure 4 Assembly drawing of a faulty TVA valve provided by an embodiment of the present invention;

[0025] Figure 5 Comparison chart of the actual value and the model value of the fresh air intake provided by an embodiment of the present invention.

[0026] Wherein:

[0027] 1 - air filter, 2 - supercharger, 3 - TVA valve, 4 - EGR valve, 5 - engine, 6 - gear shaft, 7 - DC motor, 8 - valve disc, 9 - return spring, 10 - position sensor, 11 - cut-off point, 12 - normal fresh air intake, 13 - faulty fresh air intake. Detailed implementation manners

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] In order to enable those skilled in the art of the present technology to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0030] Please refer to Figures 1 to 5 , wherein, Figure 1 is the flow chart of the method for simulating abnormal fresh air intake of a diesel engine provided by an embodiment of the present invention, Figure 2 is the schematic diagram of the intake and exhaust system, Figure 3 is the assembly drawing of a normal TVA valve in the prior art, Figure 4 is the assembly drawing of a faulty TVA valve provided by an embodiment of the present invention, Figure 5 is the comparison chart of the actual value and the model value of the fresh air intake provided by an embodiment of the present invention.

[0031] In the first specific embodiment, the method for simulating abnormal fresh air intake of a diesel engine provided by the present invention includes: S1, cutting off the gear shaft 6 connected to the valve plate 8; S2, adjusting the opening of the TVA valve 3; S3, measuring the actual value of the fresh air intake of the engine 5; S4, comparing the actual value with the model value of the fresh air intake.

[0032] The failure of TVA valve 3 affects the intake system of engine 5, resulting in abnormal intake, which may directly affect the emission results of engine 5. The abnormal simulation of fresh intake volume needs to achieve two aspects: first, a specific OBD fault special part needs to be made, that is, the gear shaft 6 connected to the valve plate 8 is cut and cut in step S1, so that a cutoff point 11 appears between the gear shaft 6 and the valve plate 8. When the ECU gives the TVA valve 3 an operating voltage, the TVA valve 3 does not operate according to the specified opening and can be manually set to a fixed opening, that is, the opening of the TVA valve 3 is adjusted in step S2, so that the ECU can perform logical judgment and realize the error reporting of abnormal fresh intake volume. The measurement data generated by this invention is only obtained by blocking the TVA valve 3 at a fixed opening. Second, when simulating the abnormal fresh intake volume, the TVA valve 3 must not be completely stuck, otherwise it will cause the OBD to monitor irrelevant faults and affect the actual experimental results.

[0033] On the basis of simulating the intake abnormality, corresponding data collection and analysis are carried out, namely, measuring the actual value of the fresh air intake of the engine 5 in step S3 and step S4 and comparing the actual value with the model value of the fresh air intake, so as to obtain the ratio of the actual value of the fresh air intake to the valve opening. This can neither report the related faults of TVA sticking nor simulate the abnormal fresh air intake, which is of great significance for studying the fault reporting.

[0034] In the intake system, in addition to the TVA valve 3 and the engine 5, there are also an air filter 1, a supercharger 2 and an EGR valve 4; in the TVA valve 3, in addition to the gear shaft 6, the valve plate 8 and the truncation point 11 between the gear shaft 6 and the valve plate 8, there are also a DC motor 7, a return spring 9 and a position sensor 10. Except that the gear shaft 6 is cut and truncated, there is no difference from the TVA valve 3 in the prior art. Please refer to the prior art and no further description will be given here.

[0035] In this embodiment, the present invention aims to improve and adopt a TVA valve 3 with a fault to simulate the abnormal fresh air intake volume. According to the OBD-related clauses in the existing National VI emission regulations for heavy-duty vehicles, when the engine OBD certification is carried out at the National Testing and Certification Center, it is necessary to simulate the faults that may affect emissions or are related to emissions; the structural principles of the electronic TVA valve 3 produced by various manufacturers are basically the same, and the present invention has a wide range of applicability.

[0036] In addition, after step S3, it also includes S31, adjusting the rotation speed of the engine 5 and measuring the actual value of the fresh air intake of the engine 5; after step S4, it also includes S41, when the actual value is higher or lower than the model value, a fault is reported.

[0037] Among them, the TVA valve 3 is not controlled by the driving motor and can be freely adjusted within the range of 0° to 85°. The opening of the TVA valve 3 is the angle between the valve plate 8 of the TVA valve 3 and the intake direction; when the opening of the TVA valve 3 is 30°, the rotation speed ranges from 800 to 1900 rpm.

[0038] When the opening degree of the faulty TVA valve 3 is 30°, an external characteristic working condition of the engine 5 is operated, such as a speed of 800 to 1900 rpm and a throttle of 100%, and experimental data table 1 is obtained:

[0039] Table 1 Experimental results of a certain engine

[0040]

[0041] During the experiment, it was found that when the opening of the TVA valve 3 was fixed at 30°, the fresh air intake of the engine 5 was greatly affected. The opening of 30° was set as the error reporting opening and applied to the certification experiment; the fault reporting logic was that when the actual value of the fresh air intake was higher or lower than the calibrated model value of the fresh air intake, a fault was reported.

[0042] Among them, the model value of the fresh air intake amount is the actual fresh air intake amount of the engine 5 under various working conditions generated based on the normal working TVA, EGR and the performance of the engine 5, the external temperature environment and other factors, and filled in the table under the corresponding working conditions, as shown in Table 2, x is the engine 5 speed, y is the actual fuel injection amount of the engine 5, the actual calibration process is relatively complicated, and has little relevance to the present invention, so it is omitted.

[0043] Table 2 Calibration of model value of fresh air intake

[0044]

[0045] At this time, a complete OBD cycle is run using the faulty TVA valve 3 to compare the model value of the fresh air intake with the actual value of the fresh air intake, such as Figure 5 As shown, the normal fresh air intake volume 12 is the model value of the fresh air intake volume under normal conditions, and the faulty fresh air intake volume 13 is the value when the opening of the faulty TVA valve 3 is fixed at 30°. At this time, the faulty fresh air intake volume 13 is lower than the normal fresh air intake volume 12, and the OBD system of the engine 5 should recognize it and report an error.

[0046] It should be emphasized that by adjusting the opening of the TVA valve 3, the fresh air intake can achieve an ideal error reporting effect, and indirectly it can be obtained that the ratio of the actual value of the fresh air intake to the opening is of great significance for studying fault reporting; using this fault part, the abnormal intake volume can be measured on different models, and the scale calibrated on the flange surface can make the control of the fresh air intake more accurate; using this fault part, there is no need to modify the relevant calibration to achieve error reporting. The conditions for prohibiting modification of calibration to achieve error reporting as required by the testing center are met; the experimental recognition in the testing center is higher because the original machine parts are used and no other external parts are used for intervention, so it is more experimentally convincing. In the present invention, neither the related faults of TVA jamming will be reported, nor can the abnormal fresh air intake be simulated; the actual intake volume data and emission data obtained from the experiment are obtained based on the engine 5 cycle conditions specified by the regulations, and are based on specific models.

[0047] In this embodiment, EGR is the abbreviation of Exhaust Gas Re-circulation, which means that part of the exhaust gas discharged by the engine 5 is returned to the intake manifold and enters the cylinder again together with the fresh mixed gas. 2 etc. polyatomic gases, while CO 2 The gases cannot burn but absorb a lot of heat due to their high specific heat capacity, which reduces the maximum combustion temperature of the mixture in the cylinder, thereby reducing NO xThe amount of gas generated can be reduced to achieve the purpose of reducing emissions; TVA is the abbreviation of Throttle Valve, which is the abbreviation of intake throttle valve or intake throttle. It is a controllable valve that controls the air entering the engine 5. After the gas enters the intake pipe, it will mix with diesel to become a combustible mixture, which will be compressed and burned to form work. The throttles mentioned in this article are all electronic throttles, which control the opening angle of the throttle according to the intake amount required by the engine 5 through the throttle position sensor 10, thereby adjusting the size of the intake amount. OBD is the abbreviation of On-Board Diagnostics, which is an extended detection system for automobile fault diagnosis. OBD monitors the engine 5, catalytic converter, particulate filter, nitrogen oxide sensor, exhaust temperature sensor, emission control system, fuel system, intake system and other systems and components in real time, and is associated with ECU. When the above-mentioned systems or components fail, OBD detects the fault, ECU records the fault information and related codes, and issues a warning through the fault light; ECU is the abbreviation of Electronic Control Unit, which is also called "driving computer" or "on-board computer". In terms of use, it is a special microcomputer controller for automobiles; the National VI emission regulations for heavy-duty vehicles are "Heavy-duty Vehicle Pollutant Emission Limits and Measurement Methods (China Phase VI)"; calibration is to complete the research and setting of various parameters of the engine 5 under each working condition / each speed through bench experiments when the engine 5 mechanics have been determined, and after completing the technical data, the data is programmed and written into the ECU. After the calibration is completed, the engine 5 can run according to the data written into the ECU.

[0048] The present invention also provides a device for simulating the abnormal fresh air intake of a diesel engine, which uses the above-mentioned method for simulating the abnormal fresh air intake of a diesel engine, including a TVA valve 3 connected to the front end of an engine 5, the TVA valve 3 is provided with a gear shaft 6 and a valve plate 8, the gear shaft 6 connected to the upper end of the valve plate 8 is cut and truncated, at this time the TVA valve 3 is not controlled by the drive motor and can be freely adjusted, which will not be repeated here.

[0049] In addition, an intake air flow sensor is provided at the front end of the TVA valve 3. The function of the intake air flow sensor is to measure the actual value of the fresh intake air volume, which will not be described in detail here.

[0050] The above is a detailed introduction to the method and device for simulating the abnormal fresh air intake of a diesel engine provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for simulating abnormal fresh air intake of a diesel engine, It is characterized in that include, Cutting off the gear shaft (6) connected to the valve plate (8) to make a specific OBD fault special part; The opening of the TVA valve (3) is adjusted to simulate abnormal intake; wherein, based on the cutoff point (11) between the gear shaft (6) and the valve plate (8), when the ECU sets an actuation voltage for the TVA valve (3), the TVA valve (3) does not operate according to the prescribed opening and can be manually set to a fixed opening, and the ECU can perform logical judgment and realize an error report of abnormal fresh intake volume; Measuring an actual value of the fresh air intake amount of the engine (5); The actual value is compared with a model value of the fresh air intake amount.

2. The method for simulating abnormal fresh air intake of a diesel engine according to claim 1, It is characterized in that The step of measuring the actual value of the fresh air intake amount of the engine (5) specifically comprises: The rotation speed of the engine (5) is adjusted, and the actual value of the fresh air intake amount of the engine (5) is measured.

3. The method for simulating abnormal fresh air intake of a diesel engine according to claim 2, It is characterized in that The range of the opening is 0° to 85°.

4. The method for simulating abnormal fresh air intake of a diesel engine according to claim 3, It is characterized in that When the opening is 30°, the rotation speed ranges from 800 to 1900 rpm.

5. The method for simulating abnormal fresh air intake of a diesel engine according to any one of claims 1 to 4, It is characterized in that After the step of comparing the actual value with the model value of the fresh intake air amount, the method further includes: When the actual value is higher or lower than the model value, a fault is reported.

6. A device for simulating abnormal fresh air intake of a diesel engine, using the method for simulating abnormal fresh air intake of a diesel engine as claimed in any one of claims 1 to 5, It is characterized in that The invention comprises a TVA valve (3) connected to the front end of an engine (5), wherein the TVA valve (3) is provided with a gear shaft (6) and a valve plate (8), and the gear shaft (6) connected to the upper end of the valve plate (8) is cut and truncated.

7. The device for simulating abnormal fresh air intake of a diesel engine according to claim 6, It is characterized in that An intake air flow sensor for measuring real-time intake air flow is provided at the front end of the TVA valve (3).

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