A method and structure for controlling the injection phase of a direct injection engine with random injection in each cylinder

Abstract

The present application relates to a kind of direct injection engine cylinder random injection phase control method and structure, the method includes the following steps: in idle condition, in the distance 180CA between the injection pulse width of each cylinder of four-cylinder engine non-idle condition, on the basis of condition, increase maximum available injection phase angle deviation offset max , in the maximum available injection phase angle deviation offset max Range, random access injection phase angle deviation offset random ∈(‑|offset max |,|offset max |), the injection phase angle deviation offset random Including offset1 random , offset2 random , offset3 random And offset4 random Compared with the prior art, the present application offsets the speed fluctuation generated by engine combustion deviation, improves idle stability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of engine electronic control system, and relates to a control method and structure for random injection phase of a direct injection engine. BACKGROUND

[0002] With the increasingly stringent requirements of the state on automobile emissions and the increasingly high requirements of the general public on vehicle driving, higher requirements are put forward for the precise control of engine fuel. Due to factors such as material and layout direction, the fuel system part of the engine will produce fuel pulsation during fuel injection, which will produce different pulsation pressures at each fuel injector, thereby causing uneven fuel injection in each cylinder of the engine. In particular, for a direct injection engine (GDI) engine using a high-pressure fuel system, the oil rail generally adopts a design scheme without a damper, and the influence of fuel pulsation is greater. If the engine cylinder is lean, the oil-gas mixture will have excess oxygen, and in the high-temperature oxygen-rich state, the engine nitrogen oxide (NO x ) original emission will be increased; if the engine cylinder is rich, the unburned mixture will be discharged from the cylinder, which will increase the emission of hydrocarbons (HC), carbon monoxide (CO), etc. At the same time, uneven fuel injection in each cylinder will cause different combustion explosion pressures in each cylinder of the engine, causing the engine to run unevenly, especially at idle speed, the uneven running of the engine will cause obvious speed fluctuations, which will be transmitted to the vehicle driving cabin through the transmission system, causing an adverse driving experience.

[0003] In order to reduce idle speed fluctuations and improve the driving experience, the control method of the traditional GDI engine is to increase the idle speed, increase the actual intake of the engine, improve the robustness of the engine control, and reduce the speed fluctuations. However, this scheme increases the idle fuel consumption due to the increase in speed.

[0004] Patent CN101694184A discloses an engine starting fuel injection control method, which determines the opening time of the fuel injector according to the fuel injection time, and determines the opening duration of the fuel injector according to the fuel injection pulse width; wherein the fuel injection time and the fuel injection cylinder number are determined according to the detected engine crankshaft signal and phase signal; the fuel injection pulse width is determined according to the detected engine temperature, and is compensated according to the detected battery voltage. However, this patent does not explain the specific calculation method of the fuel injection reference tooth and the fuel injection phase, which has limitations.

[0005] Patent CN114542311A discloses a direct injection engine low-temperature environment in-cylinder direct injection control method and system, the critical crank angle corresponding to the oil injection wet wall is calculated according to the basic parameters of the oil injector and the combustion system; the oil injection parameters of the oil injector are calibrated with the calibrated oil injection end angle being less than the critical crank angle as the calibration principle; whether the direct injection engine is in a low-temperature environment is judged, if it is in a low-temperature environment, the oil injection parameters of the oil injector are executed to complete the in-cylinder gasoline direct injection in the low-temperature environment. But this patent more from the calibration level tries to avoid oil dilution, provides a basis for the selection of oil injection phase, does not explain the oil injection phase reference and range from the system logic level, and cannot solve the problem of speed fluctuation at idle speed. SUMMARY

[0006] The purpose of the present application is to overcome at least one of the above-mentioned defects in the prior art and to provide a direct injection engine cylinder-by-cylinder random oil injection phase control method and structure. The present application realizes random variation of the oil injection time of each cylinder of the direct injection engine within the calibratable range under idle operating conditions, offsets the speed fluctuation caused by engine combustion deviation, and improves idle stability.

[0007] The purpose of the present application can be achieved by the following technical solutions:

[0008] One of the technical solutions of the present application is to provide a direct injection engine cylinder-by-cylinder random oil injection phase control method, which comprises the following steps:

[0009] Under non-idle operating conditions, the distance between the oil injection pulse widths of each cylinder of the four-cylinder engine is 180CA° (degree of crank angle);

[0010] Under idle operating conditions, in order to realize independent controllability of the oil injection time of each cylinder of the engine, reduce harmful gas emissions of the engine, reduce idle fluctuation of the engine, and improve stability of fuel injection control of the engine, the maximum calibratable oil injection phase angle deviation offset is increased on the basis of the distance of 180CA° between the oil injection pulse widths of each cylinder of the four-cylinder engine. max Within the range of the maximum calibratable oil injection phase angle deviation offset max , the electronic control unit randomly retrieves the oil injection phase angle deviation offset random ∈(-|offset max |,|offset max |), the oil injection phase angle deviation offset random includes the first cylinder oil injection phase angle deviation offset1 random , the second cylinder oil injection phase angle deviation offset2 random , the third cylinder oil injection phase angle deviation offset3 randomand fourth cylinder injection phase angle offset4 random The interval of the injection time of each cylinder can be randomly controlled under idle working condition.

[0011] The injection sequence of the four-cylinder engine is first cylinder-third cylinder-fourth cylinder-second cylinder (1-3-4-2), and the reference teeth of each cylinder are separated by 180CA°.

[0012] The distance between the injection pulse width of the first cylinder and the third cylinder is 180CA°+offset1 random -offset3 random ;

[0013] The distance between the injection pulse width of the third cylinder and the fourth cylinder is 180CA°+offset3 random -offset4 random ;

[0014] The distance between the injection pulse width of the fourth cylinder and the second cylinder is 180CA°+offset4 random -offset2 random ;

[0015] The distance between the injection pulse width of the second cylinder and the first cylinder is 180CA°+offset2 random -offset1 random .

[0016] Further, the maximum injection phase angle offset of each cylinder is offset max A three-dimensional calibration table is used for reading, and the X and Y coordinates in the three-dimensional calibration table are the speed and load of the engine, respectively, and the Z coordinate is the maximum injection phase angle offset max -180CA°≤offset max ≤180CA°, considering the angle of a complete stroke, the speed fluctuation is determined to be the minimum on the whole vehicle.

[0017] As a preferred technical solution, the injection time is calculated according to the cam angle and the intake valve time angle signal.

[0018] Further, the cam signal disc is a 60-2 (58) tooth structure, wherein the 58 teeth are uniformly spaced tooth top and tooth groove design, and the 2 teeth are tooth missing design.

[0019] The cam sensor measures and inputs the 60-2 tooth signal to the electronic control unit, and the electronic control unit obtains a complete 60-2 tooth signal every time the engine rotates 1 circle, and each tooth represents 6CA°.

[0020] Further, the falling edge of the 20th tooth of the signal is set as the compression top dead center (TDC1) of the first cylinder of the engine, which generally requires engine design guarantee, involving the size of the cam plate, the design of the tooth groove / tooth top, the installation angle, etc.

[0021] Further, the falling edge of the 17th tooth in the complete 60-2 tooth signal before the compression top dead center of the first cylinder is set as the first cylinder's openable injection tooth, which is logically 3 teeth ahead of the injection phase to reserve space, and in principle, can realize the exhaust stroke injection of the engine in the previous cycle, which can be used in special scenarios, such as in the cold state, in order to prevent oil dilution, a part of fuel is injected into the cylinder at the end of the exhaust stroke, and the fuel is heated by the residual temperature in the cylinder.

[0022] Further, the falling edge of the 23rd tooth in the complete 60-2 tooth signal at the compression top dead center of the first cylinder is set as the first cylinder's endable injection tooth, which is logically 3 teeth behind the injection phase to reserve space, and in theory, can realize the short-term continuous injection during the working stroke, which can make up for the insufficient flow of the injector in special scenarios.

[0023] In theory, the injection can be performed between the openable injection tooth and the endable injection tooth, and the openable injection tooth time and the endable injection tooth time are set as the injection boundary line.

[0024] Further, the compression top dead center of the first cylinder is set as the injection reference tooth;

[0025] The phase length from the opening time angle of the injection pulse width to the injection reference tooth is set as the injection angle SOI (start of injection), which can be calibrated and can be positive or negative, and is selected according to the optimal fuel consumption of the engine on the test bench.

[0026] Further, the injection reference tooth of the third cylinder is set as the falling edge of the 50th tooth in the complete 60-2 tooth signal at the compression top dead center of the first cylinder;

[0027] The injection reference tooth of the fourth cylinder is set as the falling edge of the 20th tooth in the complete 60-2 tooth signal after the compression top dead center of the first cylinder;

[0028] The injection reference tooth of the second cylinder is set as the falling edge of the 50th tooth in the complete 60-2 tooth signal after the compression top dead center of the first cylinder.

[0029] Further, in the idling condition, the phase length from the opening time angle of the random injection pulse width of each cylinder with the random phase opening function to the injection reference tooth is as follows:

[0030] The phase length from the opening time angle of the random injection pulse width of the first cylinder to the injection reference tooth is SOI+offset1 random;

[0031] The phase length from the opening time angle of the random fuel injection pulse width of the second cylinder to the fuel injection reference tooth is SOI+offset2 random ;

[0032] The phase length from the opening time angle of the random fuel injection pulse width of the third cylinder to the fuel injection reference tooth is SOI+offset3 random ;

[0033] The phase length from the opening time angle of the random fuel injection pulse width of the fourth cylinder to the fuel injection reference tooth is SOI+offset4 random .

[0034] One of the technical solutions of the present application is to provide a direct injection engine cylinder random fuel injection phase control structure, which realizes the method, and is electrically connected with an electronic control unit (ECU), wherein a calculation required chart is stored in the electronic control unit, and the structure comprises a low-pressure part and a high-pressure part.

[0035] In the low-pressure part, the oil tank is connected with a fuel pump, the fuel pump is connected with a low-pressure pipeline, and the fuel pump is electrically connected with the electronic control unit.

[0036] In the high-pressure part, a high-pressure fuel pump is connected with the low-pressure pipeline and a high-pressure pipeline, and the high-pressure fuel pump is electrically connected with the electronic control unit.

[0037] The high-pressure pipeline is connected with a high-pressure oil rail, a cylinder and a crankshaft are arranged in the engine, the high-pressure oil rail is connected with an injector, the high-pressure oil rail sprays fuel into the cylinder through the injector, one end of the crankshaft extending out of the cylinder is connected with a crank position signal disc, a crank position sensor is arranged beside the crank position signal disc, and the injector and the crank position sensor are electrically connected with the electronic control unit.

[0038] As a preferred technical solution, the oil tank is connected with the fuel pump through a circulating pipeline.

[0039] As a preferred technical solution, the electronic control unit controls the fuel pump to suck fuel from the oil tank to the low-pressure pipeline, keeps the oil pressure in the low-pressure pipeline stable, and returns the excess fuel to the oil tank.

[0040] As a preferred technical solution, the high-pressure fuel pump is connected with a drive cam.

[0041] As a preferred technical solution, the drive cam is arranged on a camshaft, one end of the camshaft is connected with a cam signal disc, the other end of the camshaft is connected with a variable valve timing (VVT) phaser, a cam position sensor is arranged beside the cam signal disc, and the VVT phaser and the cam position sensor are electrically connected with the electronic control unit.

[0042] As a preferred technical scheme, the driving cam drives the piston of the high-pressure oil pump to go up, the electronic control unit controls the high-pressure oil pump to close the execution valve of the high-pressure oil pump at a proper time, and fuel is forcibly pumped into the high-pressure pipeline by using the energy of the piston going up.

[0043] The electronic control unit controls the rotation offset of the variable valve timing phaser, the rotation offset of the variable valve timing phaser drives the rotation offset of the camshaft, thereby changing the valve lift and realizing continuous variable valve timing.

[0044] The relative rotation offset information of the variable valve timing phaser is represented by the offset position of the cam signal disc, the cam position sensor captures the offset position information of the cam signal disc and transmits the offset position information to the electronic control unit, and the electronic control unit calculates the final variable valve timing phase opening degree.

[0045] As a preferred technical scheme, the high-pressure oil rail is provided with an oil pressure sensor, and the oil pressure sensor is electrically connected to the electronic control unit.

[0046] As a preferred technical scheme, the oil pressure sensor measures the pressure information in the high-pressure pipeline in a timely manner and feeds back the electronic control unit.

[0047] The electronic control unit controls the output driving signal of the high-pressure oil pump, controls the high-pressure oil pump switch, and pressurizes the proper amount of fuel to maintain the theoretical fuel rail pressure.

[0048] The electronic control unit calculates the required fuel injection amount of each cylinder of the injector in combination with the current speed and load information of the engine, calculates the final fuel injection pulse width and fuel injection phase of each cylinder, and outputs the final fuel injection pulse width and fuel injection phase to each cylinder of the injector for execution.

[0049] The crank position sensor feeds back the tooth signal in the crank position signal disc, and is used to calculate the real crankshaft position and speed information of the engine.

[0050] One of the technical schemes of the present application is to provide a direct injection engine cylinder-by-cylinder random fuel injection phase control device, which comprises a memory, a processor, and a computer program stored in the memory, and the processor executes the computer program to realize the steps of the method.

[0051] One of the technical schemes of the present application is to provide a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to realize the steps of the method.

[0052] One of the technical schemes of the present application is to provide a computer program product, which comprises a computer program, and the computer program is executed by a processor to realize the steps of the method.

[0053] Compared with the prior art, the present application has the following beneficial effects:

[0054] (1) The present application relates to a direct injection engine cylinder split random injection phase control strategy which can reduce idle fluctuation, realizes random adjustment of the injection time of a cylinder or multiple cylinders by the control system within a calibratable time range under idle working condition, makes the injection time of each cylinder non-equidistant, and offsets the pressure pulsation in the fuel system. The injection control method realizes independent controllability of the injection time of each cylinder within one stroke by defining different injection times of each cylinder, changes the injection time randomly, makes the combustion pressure of each cylinder randomly fluctuate within a controllable range, offsets the influence of the combustion deviation of a specific cylinder on the speed fluctuation due to manufacturing deviation and the like, improves the stability of the engine at the idle stage, and effectively reduces harmful gas emission of the engine.

[0055] (2) The present application adopts random change of the injection time of each cylinder within a calibratable range on a direct injection engine under idle working condition, offsets the speed fluctuation caused by the combustion deviation of the engine, does not need to increase the idle speed, reduces idle fuel consumption, and realizes technical cost reduction. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 FIG. 1 is a schematic diagram of a direct injection engine cylinder split random injection phase control structure in an embodiment of the present application;

[0057] Figure 2 FIG. 2 is a schematic diagram of first cylinder injection time control of a direct injection engine in an embodiment of the present application;

[0058] Figure 3 FIG. 3 is a schematic diagram of direct injection engine cylinder split random injection phase control in an embodiment of the present application.

[0059] MARK DESCRIPTION IN THE DRAWINGS

[0060] 1 - oil tank, 2 - fuel pump, 3 - low pressure pipeline, 4 - cam position sensor, 5 - cam signal disc, 6 - high pressure fuel pump, 7 - driving cam, 8 - camshaft, 9 - variable valve timing phaser, 10 - engine, 11 - cylinder, 12 - high pressure pipeline, 13 - oil pressure sensor, 14 - high pressure fuel rail, 15 - injector, 16 - crankshaft, 17 - crank position signal disc, 18 - crank position sensor, 19 - electronic control unit. DETAILED DESCRIPTION

[0061] The present application will be described in detail below in combination with specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following embodiments.

[0062] EMBODIMENT

[0063] A direct injection engine cylinder split random injection phase control structure is shown in FIG. 1, which comprises an oil tank 1, a fuel pump 2, a low pressure pipeline 3, a cam position sensor 4, a cam signal disc 5, a high pressure fuel pump 6, a driving cam 7, a camshaft 8, a variable valve timing phaser 9, an engine 10, a cylinder 11, a high pressure pipeline 12, an oil pressure sensor 13, a high pressure fuel rail 14, an injector 15, a crankshaft 16, a crank position signal disc 17, a crank position sensor 18, and an electronic control unit 19. Figure 1As shown, the engine 10 is electrically connected to an electronic control unit (ECU) 19, and the ECU 19 stores calculation charts required, and the structure includes a low-pressure part and a high-pressure part;

[0064] In the low-pressure part, the oil tank 1 is communicated with a fuel pump 2 through a circulation pipeline, the fuel pump 2 is communicated with a low-pressure pipeline 3, and the fuel pump 2 is electrically connected to the ECU 19;

[0065] The ECU 19 controls the fuel pump 2 to suck fuel from the oil tank 1 to the low-pressure pipeline 3, keeps the oil pressure in the low-pressure pipeline 3 stable, and returns the excess fuel to the oil tank 1;

[0066] In the high-pressure part, a high-pressure fuel pump 6 is communicated with the low-pressure pipeline 3 and a high-pressure pipeline 12, the high-pressure fuel pump 6 is connected to a drive cam 7, and the high-pressure fuel pump 6 is electrically connected to the ECU 19;

[0067] The drive cam 7 drives the piston of the high-pressure fuel pump 6 to go up, the ECU 19 controls the high-pressure fuel pump 6 to close an execution valve of the high-pressure fuel pump 6 at a proper time, and forcibly pumps fuel into the high-pressure pipeline 12 by using the energy of the piston going up;

[0068] The drive cam 7 is arranged on a camshaft 8, one end of the camshaft 8 is connected to a cam signal disc 5, the other end is connected to a variable valve timing (VVT) phaser 9, a cam position sensor 4 is arranged beside the cam signal disc 5, and the VVT phaser 9 and the cam position sensor 4 are electrically connected to an ECU 15;

[0069] The ECU 19 controls the VVT phaser 9 to rotate and shift, the rotation and shift of the VVT phaser 9 drives the rotation and shift of the camshaft 8, thereby driving the change of valve lift, and realizing the continuous variable valve timing;

[0070] The relative rotation and shift information of the VVT phaser 9 is represented by the shift position of the cam signal disc 5, the shift position information of the cam signal disc 5 is captured by the cam position sensor 4 and then transmitted to the ECU 19, and the final variable valve timing phase opening degree is calculated by the ECU 19;

[0071] The high-pressure pipeline 12 is communicated with a high-pressure fuel rail 14, the high-pressure fuel rail 14 is provided with an oil pressure sensor 13, the engine 10 is provided with a cylinder 11 and a crankshaft 16, the high-pressure fuel rail 14 is communicated with an oil injector 15, the high-pressure fuel rail 14 sprays oil into the cylinder 11 through the oil injector 15, one end of the crankshaft 16 extending out of the cylinder 11 is connected to a crank position signal disc 17, a crank position sensor 18 is arranged beside the crank position signal disc 17, and the oil pressure sensor 13, the oil injector 15 and the crank position sensor 18 are electrically connected to the ECU 19;

[0072] The oil pressure sensor 13 measures the pressure information in the high-pressure pipeline 12 in time and feeds back to the ECU 19;

[0073] The electronic control unit 19 controls the output of the drive signal to the high-pressure oil pump 6, controls the high-pressure oil pump 6 switch, and pressurizes the appropriate amount of fuel to maintain the theoretical fuel rail pressure;

[0074] The electronic control unit 19 calculates the required fuel injection amount for each cylinder 11 of the engine 10 in combination with the current speed and load information of the engine 10, and calculates the final fuel injection pulse width and injection phase for each cylinder 11, and outputs it to the fuel injector 15 of each cylinder 11 for execution;

[0075] The crank position sensor 18 feeds back the tooth signal in the crank position signal disc 17, which is used to calculate the true crank position and speed information of the engine 10.

[0076] As shown in Figure 2 , the injection timing needs to be calculated according to the crank angle and the intake valve timing angle signal;

[0077] The crank position signal disc 17 has a 58 (60-2) tooth structure, of which 58 teeth are uniformly spaced tooth tops and tooth grooves, and 2 teeth are tooth missing designs;

[0078] The crank position sensor 18 measures and inputs the 60-2 tooth signal to the electronic control unit 19, and the electronic control unit 19 obtains a complete 60-2 tooth signal for every revolution of the engine 10, and each tooth represents a 6-degree crank angle (CA°);

[0079] The falling edge of the 20th tooth signal is set as the compression top dead center (TDC1) of the first cylinder of the engine 10, and the engine 10 is generally required to be designed to ensure that the size of the crank position signal disc 17, the tooth groove / tooth top design, the installation angle, etc. are involved;

[0080] The falling edge of the 17th tooth in the complete 60-2 tooth signal before TDC1 is set as the first cylinder's injectable opening tooth, which is logically 3 teeth ahead for the injection phase to reserve space, and in principle, it can realize the exhaust stroke injection of the engine 10 in the last cycle, which can be used in special scenarios, such as in the cold state, in order to prevent oil dilution, a part of the fuel is injected into the cylinder at the end of the exhaust stroke, and the fuel is heated by the residual heat in the cylinder;

[0081] The falling edge of the 23rd tooth in the complete 60-2 tooth signal where TDC1 is located is set as the first cylinder's injectable end tooth, which is logically 3 teeth behind for the injection phase to reserve space, and in theory, it can realize the short-term continuous injection during the power stroke, and make up for the deficiency of the small flow of the fuel injector 15 in special scenarios;

[0082] In theory, the injection can be performed between the injectable opening tooth and the injectable end tooth, and the injectable opening tooth time and the injectable end tooth time are set as the injection boundary line;

[0083] TDC1 is set as the injection reference tooth;

[0084] From the opening time angle of the fuel injection pulse width to the phase length of the fuel injection reference tooth, the fuel injection angle SOI (start of injection) is set, which can be calibrated and can be positive or negative. According to the optimal fuel consumption of the engine 10 on the test bench, SOI = 300CA° is preferred in this embodiment, which means that the fuel injection starts 300CA° before TDC1, that is, the fuel injection starts 50 teeth (the falling edge of the 30th tooth in the previous complete 60-2 tooth signal) before the falling edge of the 20th tooth signal.

[0085] Taking the four-cylinder engine 10 as an example, the fuel injection sequence is first cylinder-third cylinder-fourth cylinder-second cylinder (1-3-4-2), and the fuel injection reference teeth of each cylinder 11 are separated by 180CA°;

[0086] The fuel injection reference tooth of the third cylinder is set to the falling edge of the 50th tooth in the complete 60-2 tooth signal where TDC1 is located;

[0087] The fuel injection reference tooth of the fourth cylinder is set to the falling edge of the 20th tooth in the complete 60-2 tooth signal after TDC1;

[0088] The fuel injection reference tooth of the second cylinder is set to the falling edge of the 50th tooth in the complete 60-2 tooth signal after TDC1.

[0089] A direct injection engine cylinder random fuel injection phase control method is adopted to realize the above structure, as shown in Figure 3 , the specific steps are as follows:

[0090] In the non-idling condition, the distance between the fuel injection pulse widths of each cylinder 11 is 180CA°;

[0091] In the idling condition, in order to realize the independent controllability of the fuel injection time of each cylinder 11 of the engine 10, reduce the harmful gas emission of the engine 10, reduce the idling fluctuation of the engine 10, and improve the stability of the fuel injection control of the engine 10, on the basis of the distance of 180CA° between the fuel injection pulse widths of each cylinder 11, a maximum markable fuel injection phase angle deviation offset max is added within the range of the maximum markable fuel injection phase angle deviation offset max , the electronic control unit 19 randomly calls the fuel injection phase angle deviation offset random ∈(-|offset max |,|offset max |), the fuel injection phase angle deviation offset random includes the first cylinder fuel injection phase angle deviation offset1 random , the second cylinder fuel injection phase angle deviation offset2 random, the third cylinder injection phase angle offset3 random , and the fourth cylinder injection phase angle offset4 random , the interval of the injection timing of each cylinder 11 can be randomly controlled under idle conditions;

[0092] The maximum calibratable injection phase angle offset of each cylinder 11 max The three-dimensional calibratable table is selected, and the X and Y coordinates in the three-dimensional calibratable table are the speed and load of the engine 10, respectively, and the Z coordinate is the maximum calibratable injection phase angle offset max -180CA°≤offset max ≤180CA°, considering the angle of a complete stroke, the speed fluctuation is minimized on the whole vehicle to determine;

[0093] In this embodiment, the maximum calibratable injection phase angle offset offset max is 50CA°, the first cylinder injection phase angle offset offset1 random is 40CA°, the second cylinder injection phase angle offset offset2 random is 30CA°, the third cylinder injection phase angle offset offset3 random is 30CA°, and the fourth cylinder injection phase angle offset offset4 random is 40CA°;

[0094] The distance between the injection pulse widths of the first cylinder and the third cylinder is 180CA°+offset1 random -offset3 random =(180+40-30)CA°=190CA°;

[0095] The distance between the injection pulse widths of the third cylinder and the fourth cylinder is 180CA°+offset3 random -offset4 random =(180+30-40)CA°=170CA°;

[0096] The distance between the injection pulse widths of the fourth cylinder and the second cylinder is 180CA°+offset4 random -offset2 random =(180+40-30)CA°=190CA°;

[0097] The distance between the injection pulse widths of the second cylinder and the first cylinder is 180CA°+offset2 random -offset1 random =(180+30-40)CA°=170CA°;

[0098] At this time, the phase length from the opening timing angle of the random injection pulse width of each cylinder 11 in which the random phase function is turned on to the injection reference tooth in the idle operation is as follows:

[0099] The phase length from the opening timing angle of the random injection pulse width of the first cylinder to the injection reference tooth is SOI + offsetl random = (300 + 40) CA° = 340 CA°

[0100] The phase length from the opening timing angle of the random injection pulse width of the second cylinder to the injection reference tooth is SOI + offset2 random = (300 + 30) CA° = 330 CA°

[0101] The phase length from the opening timing angle of the random injection pulse width of the third cylinder to the injection reference tooth is SOI + offset3 random = (300 + 30) CA° = 330 CA°

[0102] The phase length from the opening timing angle of the random injection pulse width of the fourth cylinder to the injection reference tooth is SOI + offset4 random = (300 + 40) CA° = 340 CA°

[0103] The above description of the embodiments is to facilitate the ordinary skill in the art to understand and use the invention. Those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the present invention is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the scope of the present invention.

Claims

1. A method for random injection phase control of cylinders in a direct injection engine, characterized in that, The method includes the following steps: Under non-idling conditions, the distance between the injection pulse widths of each cylinder in a four-cylinder engine is 180CA°. Under idling conditions, the maximum calibrable injection phase angle deviation offset is added to the 180CA° distance between the injection pulse widths of each cylinder in a four-cylinder engine. max At the maximum calibrable fuel injection phase angle offset max Within the range, randomly select the fuel injection phase angle deviation offset. random ∈(-|offset max |,|offset max |), the fuel injection phase angle offset random Including the first cylinder injection phase angle deviation offset1 random Second cylinder fuel injection phase angle deviation offset2 random Third cylinder fuel injection phase angle deviation offset3 random offset4 of the injection phase angle of the fourth cylinder random ; The injection sequence of the four-cylinder engine is cylinder 1-cylinder 3-cylinder 4-cylinder 2, and the injection reference teeth of each cylinder are spaced 180CA° apart. The distance between the injection pulse widths of the first and third cylinders is 180CA° + offset1. random -offset3 random ; The distance between the injection pulse widths of the third and fourth cylinders is 180CA° + offset3. random -offset4 random ; The distance between the injection pulse widths of the fourth cylinder and the second cylinder is 180CA° + offset4. random -offset2 random ; The distance between the injection pulse widths of the second cylinder and the first cylinder is 180CA° + offset2. random -offset1 random .

2. The method for random injection phase control of cylinders in a direct injection engine according to claim 1, characterized in that, Maximum calibrable injection phase angle offset for each cylinder max The data is obtained using a three-dimensional calibrable table, where the X and Y coordinates represent the engine speed and load, respectively, and the Z coordinate represents the maximum calibrable injection phase angle offset. max -180CA°≤offset max ≤180CA°.

3. The method for random injection phase control of cylinders in a direct injection engine according to claim 1, characterized in that, The curved signal disk has a 60-2 tooth structure, of which 58 teeth are evenly spaced tooth tops and grooves, and 2 teeth are tooth gaps. Each tooth represents 6CA°.

4. The method for random injection phase control of cylinders in a direct injection engine according to claim 3, characterized in that, The falling edge of the 20th tooth signal is set to the compression top dead center of the first cylinder of the engine.

5. The method for random injection phase control of cylinders in a direct injection engine according to claim 4, characterized in that, The falling edge of the 17th tooth in the complete 60-2 tooth signal preceding the top dead center of the first cylinder is set as the injectable opening tooth of the first cylinder.

6. The method for random injection phase control of cylinders in a direct injection engine according to claim 5, characterized in that, The falling edge of the 23rd tooth in the complete 60-2 tooth signal where the compression top dead center of the first cylinder is located is set as the injection end tooth of the first cylinder. The timing of the start and end of the injection gates is set as the injection boundary line.

7. The method for random injection phase control of a direct injection engine according to claim 4, characterized in that, The compression top dead center of the first cylinder is set as the injection reference tooth; The phase length from the opening angle of the injection pulse width to the injection reference tooth is set as the injection angle SOI.

8. The method for random injection phase control of cylinders in a direct injection engine according to claim 7, characterized in that, The injection reference tooth of the third cylinder is set to the falling edge of the 50th tooth in the complete 60-2 tooth signal where the compression top dead center of the first cylinder is located. The injection reference tooth of the fourth cylinder is set to the falling edge of the 20th tooth in a complete 60-2 tooth signal after the compression top dead center of the first cylinder. The injection reference tooth of the second cylinder is set to the falling edge of the 50th tooth in a complete 60-2 tooth signal after the compression top dead center of the first cylinder.

9. A method for random injection phase control of cylinders in a direct injection engine according to claim 8, characterized in that, Under idling conditions, the phase length from the opening time angle of the random injection pulse width of each cylinder with the random phase function activated to the injection reference tooth is as follows: The phase length from the opening angle of the random injection pulse width of the first cylinder to the injection reference tooth is SOI+offset1. random ; The phase length from the opening angle of the random injection pulse width of the second cylinder to the injection reference tooth is SOI + offset2. random ; The phase length from the opening angle of the random injection pulse width of the third cylinder to the injection reference tooth is SOI+offset3. random ; The phase length from the opening angle of the random injection pulse width of cylinder 4 to the injection reference tooth is SOI+offset4. random .

10. A cylinder-specific random fuel injection phase control structure for a direct injection engine, characterized in that, The structure implements the method as described in any one of claims 1 to 9, wherein the engine (10) is electrically connected to the electronic control unit (19), and the structure includes a low-pressure section and a high-pressure section; In the low-pressure section, the fuel tank (1) is connected to the fuel pump (2), which is connected to the low-pressure pipeline (3), and the fuel pump (2) is electrically connected to the electronic control unit (19); In the high-pressure section, the high-pressure oil pump (6) is connected to the low-pressure pipeline (3) and the high-pressure pipeline (12), and the high-pressure oil pump (6) is electrically connected to the electronic control unit (19); The high-pressure pipeline (12) is connected to the high-pressure oil rail (14). The engine (10) is equipped with a cylinder (11) and a crankshaft (16). The high-pressure oil rail (14) is connected to the injector (15). The high-pressure oil rail (14) injects oil into the cylinder (11) through the injector (15). One end of the crankshaft (16) extending out of the cylinder (11) is connected to the crank position signal disk (17). A crank position sensor (18) is provided next to the crank position signal disk (17). The injector (15) and the crank position sensor (18) are electrically connected to the electronic control unit (19).

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