Engine injection advance angle monitoring method and engine system

Abstract

The application discloses an engine fuel injection advance angle monitoring method and an engine system. The engine fuel injection advance angle monitoring method comprises the following steps: acquiring a first vibration acceleration-time graph in real time according to a first vibration acceleration sensor; acquiring a second vibration acceleration-time graph in real time according to a second vibration acceleration sensor; acquiring a fuel injector vibration acceleration-time graph through the first graph and the second graph; acquiring a starting fuel injection time t1 according to the fuel injector vibration graph; acquiring a time t2 when a cylinder reaches a top dead center; and calculating a fuel injection advance angle according to θ = 6n(t2-t1) / 1000. The fuel injection advance angle can be monitored in real time without disassembling the engine, the monitoring method is simple, and the engine fuel injection advance angle monitoring method is suitable for different engine models and has good universality compared with the prior art.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and in particular to a method for monitoring engine injection advance angle and an engine system. Background Technology

[0002] Engine injection advance angle refers to the crankshaft angle corresponding to the piston crown's distance from top dead center at the moment the injector opens and injects fuel into the cylinder. An excessively small injection advance angle will cause severe afterburning, high fuel consumption, high exhaust temperature, and black smoke. An excessively large injection advance angle will cause rough engine operation, unstable running, increased mechanical load, and even cylinder scoring. Therefore, an incorrect injection advance angle will inevitably affect the engine's power and fuel economy. Current methods for detecting injection advance angle are mainly divided into two categories: static testing, which generally measures the fuel pump's injection advance angle using the drip method and pre-lift method; and dynamic testing.

[0003] Among the methods for dynamic detection, one existing engine injection advance angle monitoring method requires testing the injection pattern of the injection pump and high-pressure fuel lines. The measured injection pattern is then used to calibrate the vibration signal, thereby obtaining the correspondence between the vibration signal and the injection advance angle. This engine injection advance angle monitoring method requires recalibration of the vibration signal depending on the engine model, resulting in poor versatility and a cumbersome testing process. Summary of the Invention

[0004] The purpose of this invention is to provide an engine injection advance angle monitoring method and engine system to solve the problems of existing engine injection advance angle monitoring methods, which require recalibration of vibration signals for different engine models, have poor universality, and have a cumbersome testing process.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] An engine injection advance angle monitoring method includes a first vibration acceleration sensor installed at the injector or a high-pressure fuel line connected to the injector, and a second vibration acceleration sensor installed on the engine cylinder head. The engine injection advance angle monitoring method comprises:

[0007] The first vibration signal is acquired in real time based on the first vibration acceleration sensor, and a first spectrum is generated; wherein, the first spectrum is a first vibration acceleration-time spectrum;

[0008] The second vibration signal is acquired in real time based on the second vibration acceleration sensor, and a second spectrum is generated; wherein, the second spectrum is a second vibration acceleration-time spectrum;

[0009] The injector vibration spectrum is obtained based on the first spectrum and the second spectrum; wherein, the injector vibration spectrum is the injector vibration acceleration-time spectrum;

[0010] The injection start time t1 is obtained based on the injector vibration spectrum.

[0011] Obtain the time t2 when the piston reaches top dead center;

[0012] The injection advance angle is calculated based on θ = 6n(t2-t1) / 1000; where θ is the injection advance angle, °CA; n is the real-time engine speed, r / min; t1 is the start of injection, ms; and t2 is the time when the piston reaches top dead center, ms.

[0013] Preferably, the specific steps for obtaining the injector vibration spectrum based on the first spectrum and the second spectrum include:

[0014] The third vibration acceleration is obtained by subtracting the second vibration acceleration from the first vibration acceleration at the same time, and a third spectrum is generated; wherein, the third spectrum is the third vibration acceleration-time spectrum;

[0015] The third vibration acceleration of the third spectrum is subjected to Fourier transform and filtered to generate the injector vibration spectrum.

[0016] Preferably, the specific steps for obtaining the start injection time t1 based on the injector vibration spectrum include:

[0017] Calculate the slope between any two adjacent coordinate points (first injector vibration acceleration, first moment) and (second injector vibration acceleration, second moment);

[0018] The maximum slope value is obtained from all the slope values;

[0019] The time value corresponding to the first of the two coordinate points corresponding to the maximum slope value is the start time of fuel injection t1.

[0020] Preferably, the engine crankshaft is equipped with an angle sensor, and the specific steps for obtaining the moment t2 when the piston reaches top dead center include:

[0021] The crankshaft rotation angle is acquired in real time based on the angle sensor, and a crankshaft rotation angle map is generated; wherein, the crankshaft rotation angle map is a crankshaft rotation angle-time map;

[0022] Based on the crankshaft angle diagram, the moment when the first crankshaft angle is zero after the start of fuel injection t1 is obtained, which is the moment when the piston reaches top dead center t2.

[0023] Preferably, the specific steps for obtaining the time t2 when the piston reaches the top dead center include:

[0024] Calculate the slope between any two adjacent coordinate points (first injector vibration acceleration, first moment) and (second injector vibration acceleration, second moment);

[0025] Obtain the first minimum slope value after the start of fuel injection time t1;

[0026] The time t2 at which the piston reaches the top dead center is taken as the time value of the second coordinate point among the two coordinate points corresponding to the minimum slope value.

[0027] Preferably, the engine cylinder is equipped with a pressure sensor, and the specific steps for obtaining the time t2 when the piston reaches top dead center include:

[0028] The cylinder pressure is acquired in real time based on the pressure sensor, and a cylinder pressure spectrum is generated; wherein, the cylinder pressure spectrum is a cylinder pressure-time spectrum.

[0029] The time corresponding to the first cylinder pressure maximum value after the start of fuel injection t1, based on the cylinder pressure map, is the time t2 when the piston reaches top dead center.

[0030] Preferably, the engine crankshaft is equipped with an angle sensor, and the specific steps for obtaining the moment t2 when the piston reaches top dead center include:

[0031] The crankshaft angle is obtained in real time based on the angle sensor.

[0032] The position of the piston in the engine cylinder is calculated in real time based on the crankshaft rotation angle;

[0033] The volume of the engine cylinder is calculated based on the position of the piston in the engine cylinder;

[0034] Determine whether the volume of the engine cylinder is less than or equal to the set volume value after the start of fuel injection (t1).

[0035] If the volume of the engine cylinder is less than or equal to the set volume value, then the time when the volume of the first engine cylinder is less than or equal to the set volume value is taken as the time t2 when the piston reaches the top dead center.

[0036] As a preferred embodiment, after calculating the injection advance angle based on θ=6n(t2-t1) / 1000, the following steps are also included:

[0037] Obtain multiple injection advance angles corresponding to multiple crankshaft speeds;

[0038] Calculate the average of multiple injection advance angles to obtain the average injection advance angle;

[0039] Determine whether the average value of the fuel injection advance angle is normal.

[0040] Preferably, the specific steps for determining whether the average value of the fuel injection advance angle is normal include:

[0041] Determine whether the average value of the injection advance angle is within the set injection advance angle range;

[0042] If the average value of the injection advance angle is within the set injection advance angle range, then the average value of the injection advance angle is normal.

[0043] If the average value of the injection advance angle is not within the set injection advance angle range, an alarm will be issued.

[0044] An engine system used to implement the aforementioned engine injection advance angle monitoring method.

[0045] The beneficial effects of this invention are:

[0046] The purpose of this invention is to provide a method and system for monitoring the engine injection advance angle. This method involves acquiring a first vibration acceleration-time spectrum in real time using a first vibration acceleration sensor; acquiring a second vibration acceleration-time spectrum in real time using a second vibration acceleration sensor; obtaining an injector vibration acceleration-time spectrum using the first and second spectra; obtaining the injection start time t1 based on the injector vibration spectrum; obtaining the time t2 when the cylinder reaches top dead center; and calculating the injection advance angle using θ = 6n(t2-t1) / 1000. This method allows for real-time monitoring of the injection advance angle without disassembling the engine, is simple, and, compared to existing engine injection advance angle monitoring methods, is applicable to different engine models, demonstrating good versatility. Attached Figure Description

[0047] Figure 1 This is a flowchart of an engine injection advance angle monitoring method provided in a specific embodiment of the present invention;

[0048] Figure 2 This is the first graph obtained from a four-stroke engine with a rated speed of 1500 r / min, provided in a specific embodiment of the present invention.

[0049] Figure 3 This is the second graph obtained from a four-stroke engine with a rated speed of 1500 r / min, provided in a specific embodiment of the present invention;

[0050] Figure 4 This is a specific embodiment of the present invention, showing the injector vibration spectrum generated by a four-stroke engine with a rated speed of 1500 r / min;

[0051] Figure 5 This is a crankshaft angle diagram measured from a four-stroke engine with a rated speed of 1500 r / min, provided in a specific embodiment of the present invention;

[0052] Figure 6 This is a table showing the fuel injection advance angle measured for a four-stroke engine with a rated speed of 1500 r / min, provided in a specific embodiment of the present invention. Detailed Implementation

[0053] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0054] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0055] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0056] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0057] The present invention provides an engine system in which a first vibration acceleration sensor is provided at the injector or the high-pressure oil pipe connected to the injector, and a second vibration acceleration sensor is provided at the engine cylinder head.

[0058] This invention also provides a method for monitoring the engine injection advance angle, for use in the aforementioned engine system. This method can monitor the injection advance angle in real time without disassembling the engine. The method is simple and, compared to existing engine injection advance angle monitoring methods, is applicable to different engine models, exhibiting good versatility.

[0059] Specifically, such as Figure 1 As shown, the engine injection advance angle monitoring method includes the following steps:

[0060] S100. Acquire the first vibration signal in real time based on the first vibration acceleration sensor and generate a first spectrum; wherein, the first spectrum is a first vibration acceleration-time spectrum. Wherein, as... Figure 2 The image shown is the first graph obtained from a four-stroke engine with a rated speed of 1500 r / min.

[0061] S200: The second vibration signal is acquired in real time based on the second vibration acceleration sensor, and a second spectrum is generated; wherein, the second spectrum is a second vibration acceleration-time spectrum. Wherein, as... Figure 3 The image shown is the second graph obtained from a four-stroke engine with a rated speed of 1500 r / min.

[0062] S300. Obtain the injector vibration spectrum based on the first spectrum and the second spectrum; wherein, the injector vibration spectrum is the injector vibration acceleration-time spectrum.

[0063] Specifically, the steps for obtaining the injector vibration spectrum based on the first and second spectra include:

[0064] S310. The third vibration acceleration is obtained by subtracting the second vibration acceleration at the same time from the first vibration acceleration at the same time, and a third spectrum is generated; wherein, the third spectrum is the third vibration acceleration-time spectrum.

[0065] Specifically, by subtracting the second vibration acceleration from the first vibration acceleration at the same moment to obtain the third vibration acceleration, the vibration of the injector transmitted by engine vibration can be eliminated, thereby improving the accuracy of the injector vibration spectrum.

[0066] It is understandable that if other equipment or external environmental factors cause vibrations that may affect the accuracy of the injector vibration acceleration, the above methods can also be used to improve the accuracy of the injector vibration spectrum.

[0067] S320: Perform a Fourier transform on the third vibration acceleration of the third spectrum, filter it, and generate the injector vibration spectrum. Wherein, as... Figure 4The image shows the injector vibration spectrum generated for a four-stroke engine with a rated speed of 1500 r / min.

[0068] Specifically, the third vibration acceleration-time spectrum is segmented according to a set time interval. Then, a Fourier transform is performed on the third vibration acceleration-time spectrum for each set time interval, followed by filtering. Finally, the spectra of each set time interval are merged according to the time sequence to generate the injector vibration spectrum. The purpose of filtering the third vibration acceleration-time spectrum is to filter out low-frequency signals and eliminate interference signals, thereby further improving the accuracy of the obtained injector vibration spectrum.

[0069] Specifically, in this embodiment, the third vibration acceleration-time spectrum is segmented every 10ms, then Fourier transform is performed on the third vibration acceleration-time spectrum every 10ms, then filtering is performed, and finally the spectra of each 10ms duration are merged according to the time sequence to generate the injector vibration spectrum.

[0070] The specific methods for performing Fourier transform and filtering are existing technologies and will not be elaborated here.

[0071] S400. Obtain the start injection time t1 based on the injector vibration spectrum. Where t1 is the start injection time, in milliseconds.

[0072] The specific steps for obtaining the start injection time t1 based on the injector vibration spectrum include:

[0073] S410. Calculate the slope between any two adjacent coordinate points (first injector vibration acceleration, first moment) and (second injector vibration acceleration, second moment).

[0074] S420: Obtain the maximum slope value from all slope values.

[0075] S430, the time value corresponding to the first of the two coordinate points corresponding to the maximum slope value is the start time t1 of fuel injection.

[0076] It is understandable that when the slope is at its maximum, it means that the injector has started injecting fuel. Therefore, the time value corresponding to the first of the two coordinate points corresponding to the maximum slope value is the time t1 when the fuel injection starts.

[0077] S500, Obtain the time t2 when the piston reaches top dead center. Where t2 is the time, in milliseconds, when the piston reaches top dead center.

[0078] In this embodiment, the specific steps for obtaining the time t2 when the piston reaches the top dead center are as follows:

[0079] S510: The crankshaft rotation angle is acquired in real time based on the angle sensor, and a crankshaft rotation angle map is generated; wherein, the crankshaft rotation angle map is a crankshaft rotation angle-time map. The engine crankshaft is equipped with an angle sensor.

[0080] S520. Based on the crankshaft angle diagram, obtain the moment when the first crankshaft angle is zero after the start of fuel injection t1, which is the moment when the piston reaches top dead center t2.

[0081] Specifically, such as Figure 5 As shown in the figure, in this embodiment, a four-stroke engine with a rated speed of 1500 r / min is used as an example. When the piston reaches the top dead center during the exhaust process of the engine cylinder, the crankshaft angle is -360°. When the piston reaches the top dead center during the compression process, the crankshaft angle is 0°. That is, the crankshaft rotates 720° for one cycle. The time t2 when the crankshaft angle is 0° is when the piston reaches the top dead center.

[0082] Taking a two-stroke engine as an example, when the piston reaches the top dead center during the exhaust process of the engine cylinder, the crankshaft angle is 0°, and when the piston reaches the bottom dead center, the crankshaft angle is calibrated to 360°. That is, the crankshaft rotates 360° for one cycle, and the time when the crankshaft angle is 0° is the time when the piston reaches the top dead center, t2.

[0083] As an alternative, the specific steps to obtain the time t2 when the piston reaches top dead center include:

[0084] Calculate the slope between any two adjacent coordinate points (first injector vibration acceleration, first moment) and (second injector vibration acceleration, second moment). Obtain the first minimum slope value after the start of injection time t1; take the time corresponding to the second coordinate point among the two coordinate points corresponding to the minimum slope value as the time t2 when the piston reaches top dead center.

[0085] As an alternative, the engine cylinder is equipped with a pressure sensor. The specific steps for obtaining the time t2 when the piston reaches top dead center include:

[0086] The cylinder pressure is acquired in real time by the pressure sensor, and a cylinder pressure map is generated. The cylinder pressure map is a cylinder pressure-time map. The time corresponding to the first maximum cylinder pressure after the start of fuel injection t1 is obtained from the cylinder pressure map, which is the time t2 when the piston reaches top dead center.

[0087] As an alternative, the engine crankshaft is equipped with an angle sensor, and the specific steps for obtaining the time t2 when the piston reaches top dead center include:

[0088] The crankshaft angle is acquired in real time by an angle sensor; the position of the piston in the engine cylinder is calculated in real time based on the crankshaft angle; the volume of the engine cylinder is calculated based on the position of the piston in the engine cylinder; it is determined whether the volume of the engine cylinder after the start of fuel injection t1 is less than or equal to the set volume value; if the volume of the engine cylinder is less than or equal to the set volume value, the time when the volume of the first engine cylinder is less than or equal to the set volume value is taken as the time when the piston reaches top dead center t2.

[0089] It is understandable that after the start of fuel injection t1, the time when the volume of the first engine cylinder is less than or equal to the set volume value is the time when the piston reaches top dead center t2.

[0090] The specific methods for calculating the position of the piston in the engine cylinder in real time based on the crankshaft angle, and for calculating the volume of the engine cylinder based on the position of the piston in the engine cylinder, are existing technologies and will not be elaborated here.

[0091] S600. The injection advance angle is calculated based on θ = 6n(t2-t1) / 1000; where θ is the injection advance angle, °CA; n is the real-time engine speed, r / min; t1 is the start of injection, ms; t2 is the time when the piston reaches top dead center, ms.

[0092] Specifically, by collecting the real-time engine speed signal n, the angle through which the crankshaft rotates per millisecond is derived as: (360*n) / (60*1000); where n is the real-time engine speed, r / min.

[0093] The time it takes for the crankshaft to rotate from the moment the injector injects fuel to the moment the piston reaches top dead center is (t2-t1). Therefore, the injection advance angle is the angle the crankshaft rotates per millisecond multiplied by the crankshaft rotation time, i.e., θ = 6n(t2-t1) / 1000.

[0094] S700: Obtain multiple injection advance angles corresponding to multiple crankshaft speeds.

[0095] S800: Calculate the average value of multiple injection advance angles to obtain the average value of the injection advance angle.

[0096] S900: Determine if the average value of the fuel injection advance angle is normal.

[0097] Specifically, the steps to determine whether the average fuel injection advance angle is normal include:

[0098] Determine whether the average value of the injection advance angle is within the set injection advance angle range.

[0099] If the average value of the injection advance angle is within the set injection advance angle range, then the average value of the injection advance angle is normal.

[0100] If the average injection advance angle is not within the set injection advance angle range, an alarm will be issued.

[0101] Specifically, taking a four-stroke engine with a rated speed of 1500 r / min as an example, the injection advance angle of this engine is set at 21±1°CA. The injection advance angle table obtained according to the above-mentioned engine injection advance angle monitoring method is as follows: Figure 6 As shown, the calculated average injection advance angle is 21.4°CA, which is close to the design value.

[0102] Therefore, this engine injection advance angle monitoring method can monitor the injection advance angle in real time without disassembling the engine. The monitoring method is simple and, compared with the existing engine injection advance angle monitoring methods, it is applicable to different engine models and has good versatility.

[0103] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for monitoring engine injection advance angle, characterized in that, A first vibration acceleration sensor is installed at the fuel injector or the high-pressure fuel line connected to the fuel injector, and a second vibration acceleration sensor is installed on the engine cylinder head. The engine injection advance angle monitoring method includes: The first vibration signal is acquired in real time based on the first vibration acceleration sensor, and a first spectrum is generated; wherein, the first spectrum is a first vibration acceleration-time spectrum; The second vibration signal is acquired in real time based on the second vibration acceleration sensor, and a second spectrum is generated; wherein, the second spectrum is a second vibration acceleration-time spectrum; The injector vibration spectrum is obtained based on the first spectrum and the second spectrum; wherein, the injector vibration spectrum is the injector vibration acceleration-time spectrum; The injection start time t1 is obtained based on the injector vibration spectrum. Obtain the time t2 when the piston reaches top dead center; The injection advance angle is calculated based on θ=6n(t2-t1) / 1000; where θ is the injection advance angle, °CA; n is the real-time engine speed, r / min; t1 is the start of injection, ms; t2 is the time when the piston reaches top dead center, ms. The specific steps for obtaining the injector vibration spectrum based on the first and second spectra include: The third vibration acceleration is obtained by subtracting the second vibration acceleration from the first vibration acceleration at the same time, and a third spectrum is generated; wherein, the third spectrum is the third vibration acceleration-time spectrum; The third vibration acceleration of the third spectrum is subjected to Fourier transform, filtered, and the injector vibration spectrum is generated. The specific steps for obtaining the start injection time t1 based on the injector vibration spectrum include: Calculate the slope between any two adjacent coordinate points; The maximum slope value is obtained from all the slope values; The time value corresponding to the first of the two coordinate points corresponding to the maximum slope value is the start time of fuel injection t1.

2. The engine injection advance angle monitoring method according to claim 1, characterized in that, The engine crankshaft is equipped with an angle sensor. The specific steps for obtaining the time t2 when the piston reaches top dead center include: The crankshaft rotation angle is acquired in real time based on the angle sensor, and a crankshaft rotation angle map is generated; wherein, the crankshaft rotation angle map is a crankshaft rotation angle-time map; Based on the crankshaft angle diagram, the moment when the first crankshaft angle is zero after the start of fuel injection t1 is obtained, which is the moment when the piston reaches top dead center t2.

3. The engine injection advance angle monitoring method according to claim 1, characterized in that, The engine cylinder is equipped with a pressure sensor. The specific steps for obtaining the time t2 when the piston reaches top dead center include: The cylinder pressure is acquired in real time based on the pressure sensor, and a cylinder pressure spectrum is generated; wherein, the cylinder pressure spectrum is a cylinder pressure-time spectrum. The time corresponding to the first cylinder pressure maximum value after the start of fuel injection t1, based on the cylinder pressure map, is the time t2 when the piston reaches top dead center.

4. The engine injection advance angle monitoring method according to claim 1, characterized in that, The engine crankshaft is equipped with an angle sensor. The specific steps for obtaining the time t2 when the piston reaches top dead center include: The crankshaft angle is obtained in real time based on the angle sensor. The position of the piston in the engine cylinder is calculated in real time based on the crankshaft rotation angle; The volume of the engine cylinder is calculated based on the position of the piston in the engine cylinder; Determine whether the volume of the engine cylinder is less than or equal to the set volume value after the start of fuel injection (t1). If the volume of the engine cylinder is less than or equal to the set volume value, then the time when the volume of the first engine cylinder is less than or equal to the set volume value is taken as the time t2 when the piston reaches the top dead center.

5. The engine injection advance angle monitoring method according to claim 1, characterized in that, After calculating the injection advance angle based on θ=6n(t2-t1) / 1000, the following steps are also included: Obtain multiple injection advance angles corresponding to multiple crankshaft speeds; Calculate the average of multiple injection advance angles to obtain the average injection advance angle; Determine whether the average value of the fuel injection advance angle is normal.

6. The engine injection advance angle monitoring method according to claim 5, characterized in that, The specific steps for determining whether the average injection advance angle is normal include: Determine whether the average value of the injection advance angle is within the set injection advance angle range; If the average value of the injection advance angle is within the set injection advance angle range, then the average value of the injection advance angle is normal. If the average value of the injection advance angle is not within the set injection advance angle range, an alarm will be issued.

7. An engine system, characterized in that, Used to implement the engine injection advance angle monitoring method according to any one of claims 1-6.

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