Oil injection control method of V14 cylinder common rail engine

Abstract

The invention belongs to the technical field of diesel engines, and particularly discloses an oil injection control method for a V14-cylinder common rail engine, which comprises the following steps of: S1, acquiring a top dead center angle of a first cylinder from a crankshaft angle positioning parameter and a camshaft angle positioning parameter of the first cylinder of the engine; s2, a real ignition angle is obtained from the design, the final top dead center angle, capable of being recognized by the ECU, of each cylinder is obtained through the real ignition angle, meanwhile, the top dead center correction angle of each cylinder is obtained, and the relation is as follows: the real ignition angle = the final top dead center angle of each cylinder + the deviation angle set value-the top dead center correction angle of each cylinder; the phase can be recognized through the single ECU, and control over injection of the V14 engine and control over an ignition system are achieved.

Description

Technical Field

[0001] This invention belongs to the field of diesel engine technology, specifically relating to a fuel injection control method for a V14 common rail engine. Background Technology

[0002] In the field of diesel engines, especially in diesel engines used in diesel vehicles, high-pressure common rail technology is a commonly used fuel supply method. At the same time, an ECU (engine control unit) is used to manage the engine's fuel injection system. This ECU controls and regulates the fuel injection system (such as the fuel injection system, ignition system, emission control system, etc.).

[0003] In the process of controlling the fuel injection system, the ECU first processes the crankshaft speed signal and the camshaft speed signal to obtain the phase information required for engine control. After completing the crankshaft speed signal processing and camshaft speed signal processing, the management system converts the calculated fuel injection quantity and injection advance angle into injection timing and injection pulse width.

[0004] For traditional diesel engines, such as V6, V8, V10, V12, and V16 engines, the crankshaft design results in a uniform and symmetrical movement of the pistons in each cylinder. For example, in a V6 engine, the firing interval angle is 720° / 12 = 60°, meaning each cylinder ignites after a fixed 60° crankshaft rotation. In a V8 engine, the firing interval angle is 720° / 16 = 45°, also exhibiting uniformity. Because the firing interval angle of these traditional engines is uniform, it meets the requirements of current ECU technology (which relies on the core assumption that the top dead center of ignition in all cylinders is uniformly distributed along the crankshaft rotation). Therefore, by calibrating the parameters of "crankshaft angle positioning" and "camshaft angle positioning," phase identification can be achieved, thereby enabling control of the injection and ignition systems.

[0005] However, the situation is different for V14 engines, whose firing intervals are not uniform (e.g., 0°, 38.56°, 102.88°, etc.), making it impossible for a single ECU in existing technology to accurately identify its phase. Using multiple ECUs for control would not only significantly increase costs, but the synchronization issues between multiple ECUs would also make the entire system difficult to implement effectively. Summary of the Invention

[0006] The purpose of this invention is to provide a fuel injection control method for a V14 common rail engine, in which a single ECU can identify the phase and control the engine's injection and ignition systems.

[0007] The objective of this invention is achieved through the following technical solution: a fuel injection control method for a V14 common rail engine, comprising the following steps: S1. Obtain the top dead center angle of the first cylinder from the crankshaft angle positioning parameters and the camshaft angle positioning parameters of the first cylinder of the engine; S2. Obtain the actual ignition angle from the design, and then obtain the final top dead center angle of each cylinder that the ECU can recognize through the actual ignition angle. At the same time, obtain the top dead center correction angle of each cylinder. The relationship is as follows: Actual ignition angle = final top dead center angle of each cylinder + offset angle setting value - top dead center correction angle of each cylinder; S3. Based on the actual ignition angle, the ECU controls the fuel injection of the corresponding cylinder.

[0008] Preferably, S2 further includes the following steps: S21. The actual ignition angle of each cylinder is adjusted to the initial top dead center angle of each cylinder that can be recognized by the ECU. S22. Based on the engine's firing order and crankshaft structure, identify the reference cylinder (X0) and the cylinder with the same crankshaft (X1) that share the same crankshaft. The initial top dead center angle of each cylinder in cylinder S23.X0 is subtracted from the first offset to obtain the final top dead center angle. The initial top dead center angle of each cylinder in cylinder X1 is subtracted from the second offset to obtain the final top dead center angle.

[0009] Preferably, the first offset is 0° and the second offset is 42°.

[0010] Preferably, the V14 engine has 14 cylinders, and the firing order of the V14 engine is 1-13-2-14-4-12-6-10-7-8-5-9-3-11.

[0011] Preferably, the actual ignition angle sequence for each cylinder is: 0°, 38.56°, 102.88°, 141.44°, 205.72°, 244.28°, 308.56°, 347.16°, 411.44°, 450°, 514.28°, 552.84°, 617.16°, and 655.72°.

[0012] Preferably, the initial top dead center angle of each cylinder is an integer multiple of the reference angle, which is the minimum angular resolution that the ECU can recognize.

[0013] Preferably, the reference angle is 6°.

[0014] Preferably, the correction angle values ​​in the top dead center correction angle mapping table for each cylinder are positive.

[0015] Because of the adoption of the above technical solution, the present invention has the following advantages: By adjusting the actual ignition angle, the top dead center angle of each cylinder that the ECU can recognize is obtained, the phase of each cylinder is obtained, and the cylinder selection signal and the driving injection signal are output. Thus, based on the existing ECU technology, a single ECU can recognize the phase and realize the control of the injection and ignition system of a V14 engine with uneven firing interval angle. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0017] Figure 1 The present invention provides the steps of a fuel injection control method for a V14 common rail engine. Figure 2 This is a schematic diagram of the phase diagram of a V14 engine. Figure 3 The steps to obtain the final top dead center angle of each cylinder. Detailed Implementation

[0018] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] Please see Figure 1 and Figure 2 A fuel injection control method for a V14 common rail engine, comprising the following steps: S1. Obtain the top dead center angle of the first cylinder from the crankshaft angle positioning parameters and the camshaft angle positioning parameters of the first cylinder of the engine; S2. Obtain the actual ignition angle from the design, and then obtain the final top dead center angle of each cylinder that the ECU can recognize through the actual ignition angle. At the same time, obtain the top dead center correction angle of each cylinder. The relationship is as follows: Actual ignition angle = final top dead center angle of each cylinder + offset angle setting value - top dead center correction angle of each cylinder; S3. Based on the actual ignition angle, the ECU controls the fuel injection of the corresponding cylinder.

[0020] Specifically, the crankshaft is constantly rotating. The ECU monitors a signal group consisting of missing teeth and normal teeth through sensors. The crankshaft angle is located from the falling edge of the second normal tooth after the missing tooth to the top dead center (TDC1) of the first cylinder. The angle direction is positive in the clockwise (to the right) direction. In this application, the crankshaft angle is -84°, which is equivalent to 276° in the ECU calibration. The crankshaft angle of the first cylinder is calibrated as 276°.

[0021] The "camshaft angle positioning" is calibrated. The angle direction is from the top dead center of the first cylinder to the starting point of the first segment (segment number 0) of the camshaft. The positive direction of the angle is clockwise (to the right). In this application, it is -24°, or 696° (the crankshaft rotates twice for every one revolution of the camshaft). This angle is equivalent to 696° in the ECU calibration.

[0022] This invention discloses a fuel injection control method for a V14 common rail engine. By jointly positioning the crankshaft and camshaft angles of the V14 common rail engine, the ECU can accurately identify the position of the top dead center (TDC1) of the first cylinder. By adjusting the actual ignition angles to obtain the TDC angles of each cylinder that the ECU can recognize, the phase of each cylinder is obtained, and cylinder selection signals and drive injection signals are output. Therefore, based on existing ECU technology, a single ECU can identify the phase, enabling control of the injection and ignition system of a V14 engine with uneven firing intervals.

[0023] Further, please refer to Figure 3 Step S2 further includes the following steps: S21. The actual ignition angle of each cylinder is adjusted to the initial top dead center angle of each cylinder that can be recognized by the ECU. S22. Based on the engine's firing order and crankshaft structure, identify the reference cylinder (X0) and the cylinder with the same crankshaft (X1) that share the same crankshaft. The initial top dead center angle of each cylinder of S23.X0 is subtracted from the first offset to obtain the final top dead center angle, and the initial top dead center angle of each cylinder of X1 is subtracted from the second offset to obtain the final top dead center angle.

[0024] Furthermore, the firing order of the V14 engine is 1-13-2-14-4-12-6-10-7-8-5-9-3-11.

[0025] In this application, the V14 engine consists of seven crankshafts, each controlling two cylinders, resulting in seven X0 cylinders and seven X1 cylinders. The firing order is: 1-13-2-14-4-12-6-10-7-8-5-9-3-11, where 1 represents cylinder number 1, and so on, as shown in Table 1. This follows the traditional engine principle of alternating firing in the left and right columns and sequentially activating different crankshafts, without requiring significant modifications to the ECU program. The X0 series cylinders include cylinders 1, 2, 4, 6, 7, 5, and 3; the X1 series cylinders include cylinders 13, 14, 12, 10, 8, 9, and 11.

[0026] Furthermore, the V14 engine has 14 cylinders, and the actual ignition angle sequence of each cylinder is: 0°, 38.56°, 102.88°, 141.44°, 205.72°, 244.28°, 308.56°, 347.16°, 411.44°, 450°, 514.28°, 552.84°, 617.16°, and 655.72°. In this application, the crank is fixed on the crankshaft, and the included angle between adjacent cranks is 720° / 7≈102.857°. The included angle between the two rows of cylinders is a V-shaped angle. The V-shaped angle makes the firing times of the left and right rows of cylinders sharing the same crank cleverly staggered. Therefore, the actual ignition angle of the 13th cylinder in this application is 38.56°. The interval from the 13th cylinder to the next (2nd cylinder) crank ignition is 64.32°, which is exactly equal to the crank included angle of 102.88° (38.56°+64.32°=102.88°). Similarly, cylinder 2 (left row) fires using crankshaft 2. Cylinder 14 shares crankshaft 2 with cylinder 2, with an interval of 141.44° - 102.88° = 38.56°. Cylinder 4 uses crankshaft 3, with an interval of 205.72° - 141.44° = 64.32° with cylinder 14. Therefore, the ignition interval alternates between 38.56° and 64.32°. 38.56° represents the ignition interval between the left and right rows of cylinders on the same crankshaft, while 64.32° represents the ignition interval between different crankshafts. (38.56° + 64.32°) / 2 = 51.44°, which is exactly equal to the theoretical average interval: 720° / 14 ≈ 51.44°. Using this control method, the firing events of the V14 engine are evenly distributed over a long period of time throughout the entire 720° cycle, enabling the V14 engine to operate smoothly and efficiently.

[0027] Furthermore, the initial top dead center angle of each cylinder is an integer multiple of the reference angle, which is the minimum angular resolution that the ECU can recognize. Preferably, the reference angle is 6°. In this application, the crankshaft signal disk adopts a traditional 60-2 tooth structure. One revolution of the crankshaft is 360°, and each tooth represents 6°. Using the existing ECU technology, the top dead center angle of each cylinder is an integer multiple of 6°, which allows the ECU to accurately recognize the angle.

[0028] Furthermore, the correction angle values ​​in the top dead center correction angle mapping table for each cylinder are positive. Using positive correction angle values ​​simplifies the ECU program logic and constrains and simplifies the selection process of the top dead center angle for each cylinder.

[0029] Because the "top dead center angle of each cylinder" can only be an integer multiple of 6° for the ECU to accurately recognize it, the actual ignition angle is corrected to be an integer multiple of 6°, and the correction angle can only be marked as a positive value. For example, the actual ignition angle of cylinder 13 is 38.56°. Since the top dead center angle of cylinder 13 can only be marked as an integer multiple of 6° for the ECU to accurately recognize it, the actual angle is corrected to be an integer multiple of 6°, which can be marked as 36° or 42°. However, the "corrected top dead center angle of each cylinder" needs to be subtracted from the top dead center angle of each cylinder, and the correction angle can only be marked as a positive value. Therefore, the "top dead center angle of each cylinder" can only be marked as 42°, and the "corrected top dead center angle of each cylinder" is 3.4°.

[0030] Similarly, the ignition angles of each cylinder are adjusted in this way to obtain the initial top dead center angles of each cylinder, as shown in Table 3, which are 0°, -42°, -108°, -144°, -210°, -246°, -312°, -348°, -414°, -450°, -516°, -558°, -618° and -660° respectively. The corrected top dead center angles of each cylinder are shown in Table 4, which are 0°, -3.4°, -5.1°, -2.6°, -4.3°, -1.7°, -3.4°, -0.8°, -2.6°, -0°, -1.7°, -0.2°, -0.8° and -4.3° respectively.

[0031] In a common rail engine, two cylinders sharing the same crankshaft (such as cylinder 1 and cylinder 13) have their pistons reach top dead center simultaneously (one during the compression stroke and the other during the exhaust stroke). In the ECU program, the reference angles of the two cylinders sharing the crankshaft are bound at the hardware level; that is, the ECU considers their basic angles to be the same. According to the firing order, cylinder 1 ignites at 0° and cylinder 13 ignites at 38.56°, but their basic angles are bound together. The ECU's underlying logic cannot understand why their basic angles are different because these two cylinders share the crankshaft. Therefore, the angles of cylinders 1 and 13 need to be corrected to make them the same so that the ECU program can execute. In this application, cylinder 1 is already calibrated to ignite at 0°, so no first offset is required; the first offset is 0°. Cylinder 13 is calibrated to 42°, and an offset of 42° is required when calibrating to ignite at 0°; therefore, the second offset is 42°. Similarly, cylinder 1 is corrected according to the first offset, and all other X0 series cylinders must also be corrected according to the first offset; cylinder 13 is corrected according to the second offset, and all other X1 series cylinders must also be corrected according to the second offset. The first and second offsets constitute the offset angle setting value table, as shown in Table 6. This means that when the ECU executes, it will automatically offset all values ​​in the X0 and X1 columns of the "Initial Top Dead Center Angle of Each Cylinder" table according to the values ​​in the offset angle setting value table, thereby correctly solving the calibration binding problem of shared crank cylinders. As shown in Table 5, after correction, the final top dead center angles obtained for each cylinder are 0°, -42°, -108°, -102°, -210°, -204°, -312°, -306°, -414°, -408°, -516°, -516°, -618°, and -618°. As can be seen from the data in Table 5, in column X1, the final top dead center angle of each cylinder is as close as possible to the actual ignition angle, and the ignition angles of the two cylinders on the same crank are similar and are angles that the ECU can recognize.

[0032] For example, the actual ignition angle of cylinder 10 is 347.16°. According to Table 5, its final top dead center angle is 306°. In the X1 series, this cylinder needs to be increased by 42°, with a correction angle of 0.8°. Therefore, 347.2° = 306° + 42° - 0.8°. 306° is the angle that the ECU can recognize. The final top dead center angle of cylinder 6 on the same crank is 312°, which is also the angle that the ECU can recognize.

[0033] The present invention discloses a fuel injection control method for a V14 common rail engine. By adjusting the actual ignition angle, the initial top dead center angle of each cylinder can be obtained by the ECU. The X0 series cylinders and X1 series cylinders are then corrected by offset angle setting values ​​to obtain the final top dead center angle of each cylinder, thereby obtaining the phase of each cylinder and outputting cylinder selection signals and drive injection signals. Thus, based on the existing ECU technology, a single ECU can identify the phase and realize the control of the injection and ignition system of a V14 engine with uneven firing interval angle.

[0034] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A fuel injection control method for a V14 common rail engine, characterized in that, Includes the following steps: S1. Obtain the top dead center angle of the first cylinder from the crankshaft angle positioning parameters and the camshaft angle positioning parameters of the first cylinder of the engine; S2. Obtain the actual ignition angle from the design, and then obtain the final top dead center angle of each cylinder that the ECU can recognize through the actual ignition angle. At the same time, obtain the top dead center correction angle of each cylinder. The relationship is as follows: Actual ignition angle = final top dead center angle of each cylinder + offset angle setting value - top dead center correction angle of each cylinder; S3.ECU controls the ignition and fuel injection of the corresponding cylinder based on the final top dead center angle of each cylinder.

2. The fuel injection control method for a V14 common rail engine according to claim 1, characterized in that, It also includes the following steps: S21. The actual ignition angle of each cylinder is adjusted to the initial top dead center angle of each cylinder that can be recognized by the ECU. S22. Based on the engine's firing order and crankshaft structure, identify the reference cylinder (X0) and the cylinder with the same crankshaft (X1) that share the same crankshaft. The initial top dead center angle of each cylinder in cylinder S23.X0 is subtracted from the first offset to obtain the final top dead center angle. The initial top dead center angle of each cylinder in cylinder X1 is subtracted from the second offset to obtain the final top dead center angle.

3. The fuel injection control method for a V14 common rail engine according to claim 2, characterized in that, The first offset is 0°, and the second offset is 42°.

4. The fuel injection control method for a V14 common rail engine according to any one of claims 1 to 3, characterized in that, The V14 engine has 14 cylinders. The firing order of the V14 engine is 1-13-2-14-4-12-6-10-7-8-5-9-3-11.

5. The fuel injection control method for a V14 common rail engine according to any one of claims 1 to 3, characterized in that, The actual ignition angle sequence for each cylinder is: 0°, 38.56°, 102.88°, 141.44°, 205.72°, 244.28°, 308.56°, 347.16°, 411.44°, 450°, 514.28°, 552.84°, 617.16°, 655.72°.

6. The fuel injection control method for a V14 common rail engine according to any one of claims 1 to 3, characterized in that, The initial top dead center angle of each cylinder is an integer multiple of the reference angle, which is the minimum angular resolution that the ECU can recognize.

7. The fuel injection control method for a V14 common rail engine according to claim 4, characterized in that, The initial top dead center angle of each cylinder is an integer multiple of the reference angle, which is the minimum angular resolution that the ECU can recognize.

8. The fuel injection control method for a V14 common rail engine according to claim 5, characterized in that, The initial top dead center angle of each cylinder is an integer multiple of the reference angle, which is the minimum angular resolution that the ECU can recognize.

9. The fuel injection control method for a V14 common rail engine according to claim 1, 2, 3, 7 or 8, characterized in that, The reference angle is 6°.

10. The fuel injection control method for a V14 common rail engine according to claim 1, 2, 3, 7 or 8, characterized in that, The correction angle values ​​in the top dead center correction angle mapping table for each cylinder are positive.

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