Precombustion chamber fuel injection calculation method, engine control method, and vehicle

Abstract

The application discloses a pre-combustion chamber fuel injection calculation method, an engine control method and a vehicle. The pre-combustion chamber fuel injection calculation method comprises the following steps: obtaining the total intake mass of a single cycle of an engine combustion chamber; obtaining the single-cycle intake amount of a pre-combustion chamber according to the total volume value of the engine combustion chamber, the volume value of the pre-combustion chamber and the total intake mass of a single cycle of the engine combustion chamber; correcting the single-cycle intake amount of the pre-combustion chamber according to the current working condition of the engine to obtain the corrected single-cycle intake amount of the pre-combustion chamber; obtaining the single-cycle fuel injection amount of the pre-combustion chamber according to the theoretical air-fuel ratio and the corrected single-cycle intake amount of the pre-combustion chamber; and obtaining the single-cycle fuel injection pulse width of the pre-combustion chamber according to the single-cycle fuel injection amount of the pre-combustion chamber. The calculation method can realize accurate control of the pre-combustion chamber fuel injection amount, improve ignition stability, reduce problems such as pre-combustion chamber carbon deposition, high emission, insufficient pre-combustion chamber energy release and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engines, in particular to a pre-combustion chamber fuel injection calculation method, an engine control method and a vehicle. BACKGROUND

[0002] With the tightening of fuel consumption and emission regulations, the demand for engine fuel consumption reduction and thermal efficiency improvement is increasingly urgent. With the increasing market share of hybrid engines, the design of the combustion system can appropriately reduce the power, and focus on reducing engine fuel consumption and improving thermal efficiency.

[0003] In related technologies, the engine usually only uses stoichiometric combustion or lean combustion, but the stoichiometric combustion has higher fuel consumption and lower thermal efficiency than the lean combustion. Although the lean combustion can improve the specific heat ratio of the engine, reduce the engine fuel consumption and improve the thermal efficiency, it is difficult to achieve stable combustion as the fuel consumption decreases.

[0004] In addition, for engines with a pre-combustion chamber, only active pre-combustion or passive pre-combustion is used in actual application, the control strategy is single, and since the pre-combustion chamber cannot directly measure the flow or temperature and pressure, increasing sensors will have problems of difficult arrangement and increased cost, so there is difficulty in controlling the fuel injection amount in the pre-combustion chamber, the fuel injection amount control is inaccurate, and problems such as unstable ignition, pre-combustion chamber carbon deposition, high emissions, and insufficient pre-combustion chamber energy release are easily caused. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, one object of the present application is to provide a pre-combustion chamber fuel injection calculation method, which can accurately control the fuel injection amount of the pre-combustion chamber, improve the ignition stability, and reduce problems such as pre-combustion chamber carbon deposition, high emissions, and insufficient pre-combustion chamber energy release.

[0006] A second object of the present application is to provide an engine control method.

[0007] A third object of the present application is to provide a vehicle.

[0008] To solve the above problems, the first aspect of the present application provides a pre-combustion chamber fuel injection calculation method, which is used for an engine, the engine comprising an engine combustion chamber, the engine combustion chamber comprising a main combustion chamber and a pre-combustion chamber, the control method comprising: obtaining a total single-cycle intake mass of the engine combustion chamber; obtaining a single-cycle intake amount of the pre-combustion chamber according to a total volume value of the engine combustion chamber, a volume value of the pre-combustion chamber and the total single-cycle intake mass of the engine combustion chamber; correcting the single-cycle intake amount of the pre-combustion chamber according to an engine current operating condition to obtain a corrected single-cycle intake amount of the pre-combustion chamber, the engine current operating condition comprising one or more of a speed, a crank angle, a load, an intake temperature and an intake / exhaust valve opening / closing phase; obtaining a single-cycle fuel injection amount of the pre-combustion chamber according to a theoretical air-fuel ratio and the corrected single-cycle intake amount of the pre-combustion chamber; and obtaining a single-cycle fuel injection pulse width of the pre-combustion chamber according to the single-cycle fuel injection amount of the pre-combustion chamber.

[0009] According to the pre-combustion chamber fuel injection calculation method, the calculation model of the single-cycle intake amount and the single-cycle fuel injection amount in the pre-combustion chamber is designed by using parameters such as the total single-cycle intake mass, the total volume value of the engine combustion chamber, the volume value of the pre-combustion chamber and the theoretical air-fuel ratio, so that the fuel injection amount in the pre-combustion chamber can be accurately controlled, the concentration of the local mixture at the first spark plug in the pre-combustion chamber can be controlled, the PN emission can be reduced, the risk of the injection hole carbon deposition in the pre-combustion chamber can be reduced, and the wet wall and combustion stability in the pre-combustion chamber can be improved.

[0010] In some embodiments, the obtaining of the total single-cycle intake mass of the engine combustion chamber comprises: obtaining the total single-cycle intake mass of the engine combustion chamber according to the engine current operating condition, wherein the engine current operating condition further comprises an intake pressure, a residual exhaust pressure in a cylinder after the closing of the intake valve and the exhaust valve and a volume value of the engine single cylinder at the closing time of the intake valve.

[0011] In some embodiments, the correction of the single-cycle intake amount of the pre-combustion chamber according to the engine current operating condition to obtain the corrected single-cycle intake amount of the pre-combustion chamber, the engine current operating condition comprising one or more of the speed, the crank angle, the load, the intake temperature and the intake / exhaust valve opening / closing phase, comprises: determining a first correction coefficient according to the crank angle; determining a second correction coefficient according to the speed and the load; determining a third correction coefficient according to the intake temperature and the intake / exhaust valve opening / closing phase; and correcting the single-cycle intake amount of the pre-combustion chamber according to the first correction coefficient, the second correction coefficient and the third correction coefficient to obtain the corrected single-cycle intake amount of the pre-combustion chamber.

[0012] In some embodiments, the single-cycle intake amount of the pre-combustion chamber is corrected according to the first correction coefficient, the second correction coefficient and the third correction coefficient to obtain the corrected single-cycle intake amount of the pre-combustion chamber, including: obtaining the corrected single-cycle intake amount of the pre-combustion chamber by the following formula:

[0013] m0 = m * y1 * y2 * y3

[0014] Wherein, m0 is the corrected single-cycle intake amount of the pre-combustion chamber, m is the single-cycle intake amount of the pre-combustion chamber, y1 is the first correction coefficient, y2 is the second correction coefficient, and y3 is the third correction coefficient.

[0015] In some embodiments, the single-cycle injection pulse width of the pre-combustion chamber is obtained according to the single-cycle injection amount of the pre-combustion chamber, including: correcting the single-cycle injection amount of the pre-combustion chamber according to the current working condition of the engine to obtain the corrected single-cycle injection amount of the pre-combustion chamber, wherein the current working condition of the engine further includes the injection timing of the pre-combustion chamber and the ignition timing of the pre-combustion chamber; obtaining the single-cycle injection pulse width of the pre-combustion chamber according to the corrected single-cycle injection amount of the pre-combustion chamber.

[0016] In some embodiments, the single-cycle injection amount of the pre-combustion chamber is corrected according to the current working condition of the engine to obtain the corrected single-cycle injection amount of the pre-combustion chamber, wherein the current working condition of the engine further includes the injection timing of the pre-combustion chamber and the ignition timing of the pre-combustion chamber, including: determining a fourth correction coefficient according to the speed and the load; determining a fifth correction coefficient according to the injection timing and the ignition timing; correcting the single-cycle injection amount of the pre-combustion chamber according to the fourth correction coefficient and the fifth correction coefficient to obtain the corrected single-cycle injection amount of the pre-combustion chamber.

[0017] In some embodiments, the single-cycle injection amount of the pre-combustion chamber is corrected according to the fourth correction coefficient and the fifth correction coefficient to obtain the corrected single-cycle injection amount of the pre-combustion chamber, including: obtaining the corrected single-cycle injection amount of the pre-combustion chamber by the following formula:

[0018]

[0019] Wherein, m2 is the corrected single-cycle injection amount of the pre-combustion chamber, m1 is the single-cycle injection amount of the pre-combustion chamber, f1 is the fourth correction coefficient, and f2 is the fifth correction coefficient.

[0020] The single-cycle injection amount of the pre-combustion chamber is obtained according to the theoretical air-fuel ratio and the corrected single-cycle intake amount of the pre-combustion chamber, including: the single-cycle injection amount of the pre-combustion chamber is obtained by the following formula:

[0021] m1=m0 / X

[0022] Wherein, m0 is the corrected single-cycle intake amount of the pre-combustion chamber, and X is the theoretical air-fuel ratio.

[0023] In some embodiments, the single-cycle intake amount of the pre-combustion chamber is obtained according to the total volume value of the engine combustion chamber, the volume value of the pre-combustion chamber and the single-cycle total intake mass of the engine combustion chamber, including:

[0024] The single-cycle intake amount of the pre-combustion chamber is obtained by the following formula:

[0025]

[0026] Wherein, m is the single-cycle intake amount of the pre-combustion chamber, M is the single-cycle total intake mass of the engine combustion chamber, V1 is the volume value of the pre-combustion chamber, and V is the total volume value of the engine combustion chamber.

[0027] The second aspect embodiment of the present application provides a control method of an engine, including: determining the operating condition of the engine according to the speed and load; selecting a combustion mode from a plurality of combustion modes according to the operating condition of the engine, wherein the plurality of combustion modes include a first combustion mode and a second combustion mode, the first combustion mode adopts an equivalent ratio combustion mode for the main combustion chamber and a passive pre-combustion mode for the pre-combustion chamber, the second combustion mode adopts a lean combustion mode for the main combustion chamber and an active pre-combustion mode for the pre-combustion chamber, and the injection amount of the pre-combustion chamber is calculated according to the pre-combustion chamber injection calculation method of the above-mentioned embodiments in the active pre-combustion mode; and controlling the engine to execute the selected combustion mode.

[0028] According to the control method of the engine, the operation condition of the engine is determined according to the speed and the load of the engine, and the combustion mode executed by the engine is controlled according to the operation condition of the engine, that is, different combustion modes can be controlled to be executed by the engine under different operation conditions, so that the engine is no longer controlled to operate in a single control strategy, and the combustion mode of the engine is more in line with the operation condition of the engine. Meanwhile, when the engine is controlled to execute the first combustion mode or the second combustion mode, the advantages of the passive pre-combustion mode and the active pre-combustion mode are also considered, and the passive pre-combustion mode or the active pre-combustion mode is matched with the equivalent ratio combustion mode or the lean combustion mode in a strategy, so as to control the engine to operate in a combination of the equivalent ratio combustion mode and the passive pre-combustion mode or in a combination of the lean combustion mode and the active pre-combustion mode. In this way, the output torque and the output power of the engine can meet the driving demand, and the fuel consumption of the engine can be effectively reduced, the NOx emission can be reduced, and the thermal efficiency of the engine can be improved. In addition, when the pre-combustion chamber is controlled to operate in the active pre-combustion mode, the fuel injection amount of the pre-combustion chamber is controlled by the fuel injection calculation method of the pre-combustion chamber in the above embodiment, so that the fuel injection amount of the pre-combustion chamber can be accurately controlled, the ignition stability can be improved, and problems such as pre-combustion chamber carbon deposition, high emission, insufficient pre-combustion chamber energy release and the like can be reduced.

[0029] In some embodiments, the determining the operation condition of the engine according to the speed and the load comprises: if the speed is greater than a first preset speed and less than a second preset speed, and the load is greater than a first preset load threshold and less than a second preset load threshold, or the load is at a maximum allowable load threshold, it is determined that the engine is in a high-load operation condition; if the speed is less than the first preset speed, and the load is greater than a third preset load threshold and less than the maximum allowable load threshold, or the speed is greater than the first preset speed and less than the second preset speed, and the load is greater than the second preset load threshold and less than the maximum allowable load threshold, or the speed is greater than the second preset speed, and the load is greater than the first preset load threshold and less than the maximum allowable load threshold, it is determined that the engine is in a normal operation condition, wherein the first preset speed < the second preset speed, the first preset load threshold < the third preset load threshold < the second preset load threshold < the maximum allowable load threshold.

[0030] In some embodiments, the selecting one combustion mode from the plurality of combustion modes according to the operation condition of the engine comprises: if the engine is in the high-load operation condition, the first combustion mode is selected; if the engine is in the normal operation condition, the first combustion mode or the second combustion mode is selected.

[0031] In some embodiments, if the engine is in the normal operation condition, selecting the first combustion mode or the second combustion mode comprises: after determining that the engine is in the normal operation condition, obtaining a mixture dilution degree λ0; if the mixture dilution degree λ0 satisfies a first mixture dilution degree range, selecting the first combustion mode; if the mixture dilution degree λ0 satisfies a second mixture dilution degree range, selecting the second combustion mode.

[0032] In some embodiments, in the second combustion mode, when the pre-chamber is controlled to operate in the active pre-combustion mode, a local mixture dilution degree λ1 at a first spark plug in the pre-chamber satisfies a local mixture dilution degree range.

[0033] In some embodiments, the first mixture dilution degree range is 0.7≤λ0≤1.3, the second mixture dilution degree range is λ0≥2, and the local mixture dilution degree range is 0.7≤λ1≤1.1.

[0034] In some embodiments, the main combustion chamber is provided with a second spark plug, the plurality of combustion modes further comprises a third combustion mode, the third combustion mode is that the main combustion chamber adopts an equivalent ratio combustion mode, and the second spark plug is ignited, and the determining the operation condition of the engine according to the speed and the load further comprises: if the speed is less than the first preset speed and the load is less than a third preset load threshold, or the speed is greater than the first preset speed and the load is less than the first preset load threshold, determining that the engine is in a cold start operation condition or a catalyst heating condition; and selecting a combustion mode from the plurality of combustion modes according to the operation condition of the engine, further comprising: if the engine is in the cold start operation condition or the catalyst heating condition, selecting the third combustion mode.

[0035] The third aspect of the embodiments of the present application provides a vehicle, comprising: an engine and an engine controller; a memory in communication connection with the engine controller; wherein the memory stores a computer program executable by the engine controller, and the engine controller implements the pre-chamber fuel injection calculation method or the engine control method of the above-mentioned embodiments when executing the computer program.

[0036] The vehicle according to the embodiments of the present application can realize accurate control of the pre-chamber fuel injection amount, improve ignition stability, and reduce problems such as pre-chamber carbon deposition, high emissions, insufficient energy release of the pre-chamber, and the like, by using the pre-chamber fuel injection calculation method or the engine control method provided in the above-mentioned embodiments through the engine controller.

[0037] Additional aspects and advantages of the present application will be apparent from the following description, taken in conjunction with the accompanying drawings, wherein: BRIEF DESCRIPTION OF DRAWINGS

[0038] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the accompanying drawings, in which:

[0039] Figure 1 is a structural schematic diagram of an engine according to an embodiment of the present application;

[0040] Figure 2 is a flow chart of a pre-combustion chamber fuel injection calculation method according to an embodiment of the present application;

[0041] Figure 3 is a CFD simulation result schematic diagram of single-cycle intake volume in a pre-combustion chamber under different operating conditions according to an embodiment of the present application;

[0042] Figure 4 is a flow chart of a pre-combustion chamber fuel injection calculation method according to another embodiment of the present application;

[0043] Figure 5 is a flow chart of a control method of an engine according to an embodiment of the present application;

[0044] Figure 6 is an operating condition distribution schematic diagram of an engine according to an embodiment of the present application;

[0045] Figure 7 is a local schematic diagram of a first spark plug in a pre-combustion chamber according to an embodiment of the present application;

[0046] Figure 8 is a mixed gas dilution degree change schematic diagram when switching from a lean burn mode to an equivalence ratio combustion mode according to an embodiment of the present application;

[0047] Figure 9 is a structural schematic diagram of a vehicle according to an embodiment of the present application.

[0048] REFERENCE NUMERALS:

[0049] Vehicle 1000; Engine 900;

[0050] Engine combustion chamber 1; Engine controller 2; Memory 3.

[0051] Main combustion chamber 10; Pre-combustion chamber 11; First spark plug 110; First fuel injector 111; Second fuel injector 112. DETAILED DESCRIPTION

[0052] Embodiments of the present application are described in detail below with reference to the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary, and embodiments of the present application are described in detail below.

[0053] Since there is no relevant sensor to detect data in the existing pre-combustion chamber, the fuel injection amount of the pre-combustion chamber cannot be controlled. To solve the above problems, the first aspect of the present application provides a pre-combustion chamber fuel injection calculation method. The method can accurately control the fuel injection amount of the pre-combustion chamber, improve the ignition stability, and reduce the problems of pre-combustion chamber carbon deposition, high emissions, and insufficient energy release of the pre-combustion chamber.

[0054] In embodiments, as shown in Figure 1 , the engine 900 includes an engine combustion chamber 1, and the engine combustion chamber 1 includes a main combustion chamber 10 and a pre-combustion chamber 11. The pre-combustion chamber 11 communicates with the main combustion chamber 10 through a plurality of injection holes, and the pre-combustion chamber 11 is provided with a first fuel injector 111 and a first spark plug 110, so that the pre-combustion chamber 11 can be controlled to operate in an active pre-combustion mode and a passive pre-combustion mode according to whether the first fuel injector 111 of the pre-combustion chamber 11 sprays fuel. The main combustion chamber 10 is provided with a second fuel injector 112 which is side-mounted or centrally mounted, and the second fuel injector 112 can be an in-cylinder direct injection fuel injector.

[0055] In actual application, the pre-combustion chamber 11 can be used as an igniter, the first fuel injector 111 in the pre-combustion chamber 11 sprays fuel to configure a target air-fuel ratio for the pre-combustion chamber 11, and is beneficial to sweep away the exhaust gas in the pre-combustion chamber 11, thereby improving the operation stability of the pre-combustion chamber 11; the second fuel injector 112 in the main combustion chamber 1 supplies main fuel to the combustion chamber.

[0056] Based on the structure of the above engine, the present application designs a calculation model of the air amount in the pre-combustion chamber, i.e. the single-cycle intake amount and the single-cycle fuel injection amount. The calculation model of the pre-combustion chamber fuel injection calculation method of the present application is described below with reference to Figure 2 , as shown in Figure 2 , the method includes at least steps S1-S5.

[0057] Step S1: Obtain the single-cycle total intake mass of the engine combustion chamber.

[0058] In some embodiments, the single-cycle total intake mass of the engine combustion chamber can be obtained according to the current operating condition of the engine, wherein the current operating condition of the engine further includes the intake pressure, the residual exhaust gas pressure in the cylinder after the intake valve and the exhaust valve are closed, and the volume value of the engine single cylinder at the time when the intake valve is closed. For example, the calculation formula of the single-cycle total intake mass of the engine combustion chamber is as follows.

[0059]

[0060] , wherein P sr is the intake pressure, Prg V is the residual exhaust gas pressure in the cylinder after the intake valve and the exhaust valve are closed. deff R is the volume value of the single cylinder at the time when the intake valve is closed. g R is the volume value of the single cylinder at the time when the intake valve is closed. zz T is the intake air temperature in the cylinder at the time when the intake valve is closed.

[0061] In step S2, the single-cycle intake amount of the pre-combustion chamber is obtained according to the total volume value of the engine combustion chamber, the volume value of the pre-combustion chamber, and the single-cycle total intake mass of the engine combustion chamber.

[0062] In some embodiments, the single-cycle intake amount of the pre-combustion chamber is obtained by the following formula:

[0063]

[0064] wherein m is the single-cycle intake amount of the pre-combustion chamber, M is the single-cycle total intake mass of the engine combustion chamber, V1 is the volume value of the pre-combustion chamber, and V is the total volume value of the engine combustion chamber.

[0065] In step S3, the single-cycle intake amount of the pre-combustion chamber is corrected according to the current operating condition of the engine, to obtain a corrected single-cycle intake amount of the pre-combustion chamber, wherein the current operating condition of the engine includes one or more of the engine speed, the crank angle, the load, the intake air temperature, and the intake / exhaust valve opening / closing phase.

[0066] wherein the intake / exhaust valve opening / closing phase includes the intake valve opening phase, the intake valve closing phase, the exhaust valve opening phase, and the exhaust valve closing phase; and the current operating condition of the engine can be collected by setting relevant sensors, for example, a speed sensor can be configured on the engine to measure the engine speed in real time and transmit the detected data to the engine controller; a temperature sensor can be configured at the position of the intake valve of the engine to measure the intake air temperature in real time and transmit the detected data to the engine controller.

[0067] wherein the load can be a parameter for reflecting the size of the current operating load of the engine, for example, the load can be the current torque value or the brake mean effective pressure value of the engine.

[0068] In embodiments, since the load cannot be directly detected, it needs to be obtained by the engine controller according to sensor parameters such as the engine air mass or air flow, so as to judge the size of the engine operating load by the calculated load.

[0069] In some embodiments, the load can be obtained by the following formula.

[0070]

[0071] Wherein, z is the load, M is the total intake mass of the engine combustion chamber per cycle, λ0 is the dilution of the mixture, P0 is the standard atmospheric pressure 1013hPa, Vd is the single cylinder displacement of the engine, T0 is the standard temperature 273K, and Rg is the gas constant.

[0072] In addition, in the actual working process, the single-cycle intake amount of the pre-chamber is disturbed by the current working condition of the engine, such as the crank angle, the speed, the load, the intake temperature, and the opening / closing phase of the intake and exhaust valves, which will affect the single-cycle intake amount of the pre-chamber. Therefore, in order to accurately control the fuel injection amount in the pre-chamber, the single-cycle intake amount of the pre-chamber needs to be corrected according to the current working condition of the engine, so that the single-cycle fuel injection amount of the pre-chamber is calculated based on the corrected single-cycle intake amount of the pre-chamber, which can effectively improve the accuracy of controlling the fuel injection amount in the pre-chamber.

[0073] Step S4: obtaining the single-cycle fuel injection amount of the pre-chamber according to the theoretical air-fuel ratio and the corrected single-cycle intake amount of the pre-chamber.

[0074] Wherein, the ratio of the mass of fuel in the unit to the minimum air mass required for complete combustion of the fuel in the unit is the theoretical air-fuel ratio, i.e. the stoichiometric ratio.

[0075] Wherein, the single-cycle fuel injection amount of the pre-chamber can be calculated by the following formula.

[0076] m1=m0 / X

[0077] Wherein, m1 is the single-cycle fuel injection amount of the pre-chamber, m0 is the corrected single-cycle intake amount of the pre-chamber, and X is the theoretical air-fuel ratio.

[0078] Step S5: obtaining the single-cycle fuel injection pulse width of the pre-chamber according to the single-cycle fuel injection amount of the pre-chamber.

[0079] Specifically, the single-cycle fuel injection pulse width of the pre-chamber is calculated based on the calculated single-cycle fuel injection amount, the flow characteristics of the first fuel injector, the rail pressure, the speed and other parameters, so that the fuel injection amount of the pre-chamber is controlled according to the single-cycle fuel injection pulse width of the pre-chamber, thereby achieving the purpose of accurately controlling the fuel injection amount in the pre-chamber.

[0080] According to the pre-chamber fuel injection calculation method of the embodiment of the present application, the calculation model of the single-cycle intake amount and the single-cycle fuel injection amount in the pre-chamber is designed by using parameters such as the total intake mass per cycle, the total volume of the engine combustion chamber, the internal cavity volume of the pre-chamber, and the theoretical air-fuel ratio, so that the fuel injection amount in the pre-chamber can be accurately controlled, the concentration of the local mixture at the first spark plug in the pre-chamber can be controlled, the PN emission can be reduced, the risk of depositing carbon in the injection hole in the pre-chamber can be reduced, and the wet wall and combustion stability in the pre-chamber can be improved.

[0081] In some embodiments, the first correction coefficient is determined according to the crank angle of the engine, for example, denoted as y1; the second correction coefficient is determined according to the speed and load, for example, denoted as y2; the third correction coefficient is determined according to the intake temperature and the opening / closing phase of the intake and exhaust valves, for example, denoted as y3; and the single-cycle intake amount of the pre-chamber is corrected according to the first correction coefficient y1, the second correction coefficient y2 and the third correction coefficient y3 to obtain the corrected single-cycle intake amount of the pre-chamber. Specifically, the in-cylinder mixture simulation analysis can be performed in advance by the CFD software, the corresponding relationship between different crank angles and the first correction coefficient y1 is calibrated by simulation data, the corresponding relationship between different speeds and different loads and the second correction coefficient y2 is calibrated, and the corresponding relationship between different intake temperatures and different opening / closing phases of the intake and exhaust valves and the third correction coefficient y3 is calibrated, and is stored, that is, the crank angle of the engine and the first correction coefficient y1 have a one-to-one corresponding relationship, for example, denoted as y1 = crank angle calibration curve; the speed and load and the second correction coefficient y2 have a one-to-one corresponding relationship, for example, denoted as y2 = speed and load calibration map; the intake temperature and the opening / closing phase of the intake and exhaust valves and the third correction coefficient y3 have a one-to-one corresponding relationship, so that when calculating the corrected single-cycle intake amount of the pre-chamber, the first correction coefficient y1 can be determined according to the crank angle of the engine through the stored corresponding relationship between different crank angles and the first correction coefficient y1, the second correction coefficient y2 can be determined according to the speed and load through the stored corresponding relationship between different speeds and different loads and the second correction coefficient y2, and the third correction coefficient y3 can be determined according to the intake temperature and the opening / closing phase of the intake and exhaust valves through the stored corresponding relationship between different intake temperatures and different opening / closing phases of the intake and exhaust valves and the third correction coefficient y3. Preferably, the value range of the first correction coefficient y1 is 1.05≤y1≤1.3, the value range of the second correction coefficient y2 is 1.05≤y2≤1.3, and the value range of the third correction coefficient y3 is 1.05≤y3≤1.3. For example, referring to FIG. 2, which shows the single-cycle intake amount in the pre-chamber under different crank angles calculated by CFD simulation results under different operating conditions. Figure 3

[0082] Based on the first correction coefficient y1, the second correction coefficient y2 and the third correction coefficient y3 determined above, the corrected single-cycle intake amount of the pre-chamber can be calculated by the following formula.

[0083] m0 = m * y1 * y2 * y3

[0084] wherein m0 is the corrected single-cycle intake amount of the pre-chamber, m is the single-cycle intake amount of the pre-chamber, y1 is the first correction coefficient, y2 is the second correction coefficient, and y3 is the third correction coefficient.

[0085] ​In some embodiments, in actual working process, the single-cycle injection amount of the pre-chamber is disturbed by the current working condition of the engine, such as the engine speed, the load, the injection timing of the pre-chamber and the ignition timing, etc. which will affect the single-cycle injection amount of the pre-chamber. Therefore, in order to accurately control the injection amount in the pre-chamber, the single-cycle injection amount of the pre-chamber needs to be corrected so that when the first injector in the pre-chamber injects, the single-cycle injection amount in the pre-chamber is slightly leaner than the single-cycle intake amount in the pre-chamber to avoid local rich at the first spark plug in the pre-chamber. Specifically, the single-cycle injection amount of the pre-chamber is corrected according to the current working condition of the engine to obtain the corrected single-cycle injection amount of the pre-chamber, wherein the current working condition of the engine also includes the injection timing of the pre-chamber and the ignition timing of the pre-chamber; and the single-cycle injection pulse width of the pre-chamber is obtained according to the corrected single-cycle injection amount of the pre-chamber. Thus, by correcting the calculated single-cycle injection amount of the pre-chamber, the accuracy of the pre-chamber injection amount control can be effectively improved.

[0086] Further, the fourth correction coefficient, for example, denoted as f1, can be determined according to the speed and the load; the fifth correction coefficient, for example, denoted as f2, can be determined according to the injection timing and the ignition timing; and the single-cycle injection amount of the pre-chamber is corrected according to the fourth correction coefficient f1 and the fifth correction coefficient f2 to obtain the corrected single-cycle injection amount of the pre-chamber. Specifically, the in-cylinder mixture simulation analysis can be performed in advance by CFD software, the corresponding relationship between different speeds and different loads and the fourth correction coefficient f1 is calibrated through simulation data, and the corresponding relationship between different injection timings and different ignition timings and the fifth correction coefficient f2 is calibrated and stored. That is, the speed and the load have a one-to-one correspondence with the fourth correction coefficient f1, and the injection timing and the ignition timing have a one-to-one correspondence with the fifth correction coefficient f2. Thus, when calculating the actual single-cycle injection amount of the pre-chamber, the fourth correction coefficient f1 can be determined according to the speed and the load through the stored corresponding relationship between different speeds and different loads and the fourth correction coefficient f1, and the fifth correction coefficient f2 can be determined according to the injection timing and the ignition timing through the stored corresponding relationship between different injection timings and different ignition timings and the fifth correction coefficient f2. Preferably, the value range of the fourth correction coefficient f1 is 1.05≤f1≤1.2, for example, it can be 1.05 or 1.11 or 1.2, etc.; and the value range of the fifth correction coefficient f2 is 0.75≤f2≤1.25, for example, it can be 0.75 or 1.05 or 1.25, etc.

[0087] Based on the above fourth correction coefficient f1 and fifth correction coefficient f2, the corrected single-cycle injection amount of the pre-chamber can be calculated by the following formula.

[0088]

[0089] wherein m2 is the corrected single-cycle fuel injection amount of the pre-combustion chamber, m1 is the single-cycle fuel injection amount of the pre-combustion chamber, f1 is the fourth correction coefficient, and f2 is the fifth correction coefficient.

[0090] Reference will now be made to the following Figure 4 The pre-combustion chamber fuel injection calculation method of the embodiment of the present application is further illustrated as follows.

[0091] In step S6, the current engine operating condition is obtained, which includes one or more of the engine speed, the crank angle, the load, the intake air temperature, and the intake and exhaust valve opening / closing phase.

[0092] In step S7, the total volume value V of the engine combustion chamber, the volume value V1 of the pre-combustion chamber, and the theoretical air-fuel ratio are obtained.

[0093] In step S8, the fuel injection timing and the ignition timing of the pre-combustion chamber are obtained.

[0094] In step S9, the single-cycle total intake mass M of the engine combustion chamber is obtained according to the current engine operating condition.

[0095] In step S10, the single-cycle intake amount of the pre-combustion chamber is obtained according to the total volume value of the engine combustion chamber, the volume value of the pre-combustion chamber, and the single-cycle total intake mass of the engine combustion chamber.

[0096] In step S11, the first correction coefficient, the second correction coefficient, and the third correction coefficient are determined according to the crank angle, the speed, the load, the intake air temperature, and the intake and exhaust valve opening / closing phase of the engine.

[0097] In step S12, the single-cycle intake amount of the pre-combustion chamber is corrected according to the first correction coefficient, the second correction coefficient, and the third correction coefficient to obtain the corrected single-cycle intake amount of the pre-combustion chamber.

[0098] In step S13, the fourth correction coefficient and the fifth correction coefficient are determined according to the speed, the load, the fuel injection timing, and the ignition timing.

[0099] In step S14, the corrected single-cycle fuel injection amount of the pre-combustion chamber is obtained according to the theoretical air-fuel ratio, the corrected single-cycle intake amount of the pre-combustion chamber, the fourth correction coefficient, and the fifth correction coefficient.

[0100] In step S15, the single-cycle fuel injection pulse width of the pre-combustion chamber is obtained according to the corrected single-cycle fuel injection amount of the pre-combustion chamber.

[0101] In step S16, the fuel injection amount of the pre-combustion chamber is controlled according to the single-cycle fuel injection pulse width of the pre-combustion chamber.

[0102] Therefore, by the above steps, the single-cycle intake amount and the single-cycle injection amount in the pre-combustion chamber are calculated by the total intake mass M, the volume ratio V1 / V of the pre-combustion chamber, the crank angle, and the correction factor related to the speed and load of the engine, and the single-cycle injection amount is used to obtain the single-cycle injection pulse width of the pre-combustion chamber, so that the injection amount of the pre-combustion chamber can be accurately controlled, the concentration of the local mixture of the first spark plug is controlled, the PN emission is reduced, the risk of depositing carbon in the injection hole in the pre-combustion chamber is reduced, and the wet wall and combustion stability in the pre-combustion chamber are improved.

[0103] As shown in FIG. 1, the second aspect of the present application provides a control method of an engine, which comprises steps S17-S19, and specifically as follows. Figure 5

[0104] Step S17, determining the operating condition of the engine according to the speed and load.

[0105] Specifically, the engine has various operating conditions in the operation process, such as starting condition, idling condition, driving condition, full load condition, or gear sliding condition, etc., different operating conditions represent different working states of the engine, based on this, the speed and load of the engine are used to determine the operating condition of the engine, so as to match a more suitable combustion mode of the engine for different operating conditions.

[0106] Step S18, selecting a combustion mode from the multiple combustion modes according to the operating condition of the engine.

[0107] Among them, multiple combustion modes can be pre-set and stored according to different operating conditions of the engine, and the multiple combustion modes at least include a first combustion mode and a second combustion mode, the first combustion mode adopts an equivalence ratio combustion mode for the main combustion chamber and a passive pre-combustion mode for the pre-combustion chamber, and the second combustion mode adopts a lean combustion mode for the main combustion chamber and an active pre-combustion mode for the pre-combustion chamber, in the active pre-combustion mode, the injection amount of the pre-combustion chamber is calculated according to the pre-combustion chamber injection calculation method provided in the above embodiment.

[0108] ​In the embodiments, during the operation of the engine, fuel must be in a proper proportion with the inhaled air to form a mixture that can be combusted, and the mass ratio between the air and the fuel in the mixture is the air-fuel ratio, the mass ratio between the unit of fuel and the minimum mass of air required for complete combustion of the unit of fuel is the theoretical air-fuel ratio, i.e., the stoichiometric ratio, the mixture with the air-fuel ratio greater than the theoretical air-fuel ratio is a lean mixture, and the mixture with the air-fuel ratio less than the theoretical air-fuel ratio is a rich mixture, based on which, the stoichiometric combustion mode can be understood as a combustion mode in which the engine uses a rich mixture so that the fuel and the air can be completely combusted, and the lean combustion mode can be understood as a combustion mode in which the engine uses a lean mixture and provides a rich mixture only when needed. In the stoichiometric combustion mode, the output power of the engine is greater than that in the lean combustion mode, and the engine has stronger power; and compared with the stoichiometric combustion mode, the lean combustion mode can improve the specific heat ratio of the engine, reduce the knocking tendency, reduce the fuel consumption of the engine, and improve the thermal efficiency.

[0109] The passive pre-combustion mode is a mode in which the first fuel injector in the pre-combustion chamber is controlled not to spray fuel and the first spark plug is controlled to be ignited, and thus, by controlling the pre-combustion chamber to operate in the passive pre-combustion mode, multi-point ignition of the main combustion chamber can be achieved, the combustion efficiency of the main combustion chamber can be improved, and knocking can be reduced; and the active pre-combustion mode is a mode in which the first fuel injector in the pre-combustion chamber is controlled to spray fuel and the first spark plug is controlled to be ignited, and thus, by controlling the pre-combustion chamber to operate in the active pre-combustion mode, multi-point ignition of the main combustion chamber can be achieved, and the lean ignition stability can also be improved by spraying fuel through the first fuel injector.

[0110] In the embodiments, in the prior art, the same control strategy is used for various operating conditions of the engine, such as only the active pre-combustion mode is used for operation or only the passive pre-combustion mode is used for operation, and the control strategy is not matched with the lean combustion mode or the stoichiometric combustion mode, the control mode is single, and there are certain defects. In view of this, the control method of the embodiments of the present application no longer controls the engine to operate in a single control strategy, but controls the engine to execute different combustion modes for different operating conditions, so that the combustion mode of the engine is more in line with the actual operating conditions of the engine, and at the same time, the advantages of the passive pre-combustion mode and the active pre-combustion mode are considered, the passive pre-combustion mode or the active pre-combustion mode is matched with the stoichiometric combustion mode or the lean combustion mode in terms of strategy, and the engine is controlled to operate in the stoichiometric combustion mode combined with the passive pre-combustion mode or operate in the lean combustion mode combined with the active pre-combustion mode, so that the output torque and the output power of the engine can meet the driving requirements while effectively reducing the fuel consumption of the engine, reducing the NOx emission, and improving the thermal efficiency of the engine.

[0111] Specifically, the engine can be actually tested in advance to divide all working conditions of the engine by operating conditions according to different rotating speeds and different loads of the engine, and different combustion modes are controlled to be executed for different operating conditions to match the most suitable combustion mode for different operating conditions, that is, a plurality of different combustion modes are set in advance by actual measurement, and different combustion modes correspond to different operating conditions of the engine one by one and are stored, so that when the engine is actually applied, the combustion mode matched with the operating condition can be selected from the plurality of combustion modes according to the corresponding relationship between the different combustion modes and the different operating conditions of the engine, thereby for all working conditions of the engine, the control method can ensure that the output torque and the output power of the engine meet the driving demand, and the control method is more flexible and more suitable for different application scenarios of the engine.

[0112] Meanwhile, in different combustion modes, the running conditions of the equivalent ratio combustion mode, the lean combustion mode, the passive pre-combustion mode and the active pre-combustion mode are also comprehensively considered, and the advantages of the passive pre-combustion mode and the active pre-combustion mode are utilized to combine the equivalent ratio combustion mode with the passive pre-combustion mode as a first combustion mode, so that by controlling the main combustion chamber to run in the equivalent ratio combustion mode, the output torque and the output power of the engine can be improved, and since the mixture in the pre-combustion chamber is rich mixture, the pre-combustion chamber is controlled to run in the passive pre-combustion mode, that is, the first spark plug is ignited to realize multi-point ignition of the main combustion chamber, improve the ignition stability of the main combustion chamber, improve the combustion rate of the main combustion chamber, and the first fuel injector is controlled not to spray oil to avoid the problem of increasing fuel consumption and NOx emission due to local enrichment of the mixture, and the lean combustion mode is combined with the active pre-combustion mode as a second combustion mode, so that by controlling the main combustion chamber to run in the lean combustion mode, the fuel consumption can be reduced and the thermal efficiency can be improved, and in order to ensure the dilution of the mixture in the lean combustion mode to reduce NOx emission, the pre-combustion chamber is controlled to run in the active pre-combustion mode, that is, the first fuel injector is controlled to spray oil, so that local rich mixture can be formed at the position of the first spark plug when the first spark plug is ignited, and the ignition stability and the combustion speed are improved.

[0113] Step S20, controlling the engine to execute the selected combustion mode to meet the driving demand of the driver.

[0114] According to the engine control method of the present invention, the engine operating conditions are determined by the engine speed and load, and the combustion mode executed by the engine is determined by the engine operating conditions. That is to say, under different operating conditions, the engine can be controlled to execute different combustion modes, so that the engine operation is no longer controlled by a single control strategy, making the engine combustion mode more in line with the engine operating conditions. At the same time, under different combustion modes, the advantages of passive pre-combustion mode and active pre-combustion mode are also considered. The passive pre-combustion mode or active pre-combustion mode is matched with the stoichiometric combustion mode or lean combustion mode to control the engine to operate in a combination of stoichiometric combustion mode and passive pre-combustion mode, or in a combination of lean combustion mode and active pre-combustion mode. Thus, while ensuring that the engine output torque and output power meet the driving requirements, the engine fuel consumption is effectively reduced, NOx emissions are reduced, and engine thermal efficiency is improved. Furthermore, when controlling the pre-combustion chamber to operate in active pre-combustion mode, the fuel injection quantity of the pre-combustion chamber can be controlled by the pre-combustion chamber fuel injection calculation method of the above embodiment. This can achieve accurate control of the fuel injection quantity of the pre-combustion chamber, improve ignition stability, and reduce problems such as carbon deposits in the pre-combustion chamber, high emissions, and insufficient energy release in the pre-combustion chamber.

[0115] In some embodiments, to determine the engine's operating condition based on speed and load, the engine can be pre-tested to classify all operating states of the engine under different speeds and loads, for example, by referring to... Figure 6 The diagram shown illustrates the division of all engine operating conditions, which categorizes all engine operating states into three different operating conditions. Figure 6 The numbers 1, 2, and 3 shown represent three operating conditions of the engine. It is understood that the engine can have multiple operating conditions after being divided, and there is no restriction on this.

[0116] Specifically, refer to Figure 6 As shown, all engine operating states can be divided into high-load operating conditions and normal operating conditions. That is, based on the engine speed and load, the range of high-load operating conditions and the range of normal operating conditions are preset. High-load operating conditions can be understood as the operating conditions under which the engine operates under relatively high loads, such as... Figure 6 The area designated by number 1 and the maximum allowable load threshold curve, i.e., the external characteristic curve, represent the pre-defined range of high-load operating conditions. Normal operating conditions can be understood as the main operating conditions of the engine during operation, excluding high-load operation; that is, they encompass the engine's conventional operating conditions, such as steady-state conditions, idling conditions, and driving conditions. Figure 6The blank area divided by the middle number 2 is the range of the pre-divided normal operating condition. Therefore, based on the pre-divided operating condition of the engine, in actual application, if the speed is greater than the first preset speed v1 and less than the second preset speed v2, and the load is greater than the first preset load threshold Z1 and less than the second preset load threshold Z2, or the load is equal to the maximum allowable load threshold Z, it is determined that the engine is in a high load operating condition, that is, the operating condition of the engine is currently in the Figure 6 rectangular area shown in the middle; and in actual application, if the speed is less than the first preset speed v1, and the load is greater than the third preset load threshold Z3 and less than the maximum allowable load threshold Z, or the speed is greater than the first preset speed v1 and less than the second preset speed v2, and the load is greater than the second preset load threshold Z2 and less than the maximum allowable load threshold Z, or the speed is greater than the second preset speed v2, and the load is greater than the first preset load threshold Z1 and less than the maximum allowable load threshold Z, it is determined that the engine is in a normal operating condition. Wherein, the first preset speed v1 < the second preset speed v2, the first preset load threshold Z1 < the third preset load threshold Z3 < the second preset load threshold Z2 < the maximum allowable load threshold Z.

[0117] Wherein, the first preset speed v1, the second preset speed v2, the first preset load threshold Z1, the second preset load threshold Z2, the third preset load threshold Z3 and the maximum allowable load threshold Z are parameters set after actual testing of the engine. Wherein, the maximum allowable load threshold Z curve, that is, the external characteristic curve, can be understood as the maximum load parameter value of the engine at different speeds.

[0118] In some embodiments, when it is determined that the engine is in a high load operating condition, because the combustion temperature is high under the high load operating condition, the NOx original emission is high, and considering the case of low speed and high operating load, there is a problem of insufficient lean gas, therefore, to reduce NOx original emission, the engine is controlled to execute the first combustion mode, that is, the main combustion chamber is controlled to operate in the equivalent ratio combustion mode, to avoid the problem of further increasing NOx emission due to the adoption of lean combustion mode, reduce the pump loss, reduce the fuel consumption of the engine, and control the pre-combustion chamber to operate in the passive pre-combustion mode, so that the first fuel injector does not spray oil and the first spark plug ignites, to realize stable ignition and combustion of the main combustion chamber, avoid the problem of increasing NOx emission and fuel consumption due to the local mixture being enriched by the first fuel injector spraying oil, and also realize multi-point ignition, shorten the combustion duration, and improve the thermal efficiency and output power of the engine.

[0119] And if it is determined that the engine is in a normal operating condition, the engine is controlled to execute the first combustion mode or the second combustion mode. Specifically, since the normal operating condition includes main operating conditions of the engine, such as steady state condition, idle condition and driving condition, the dilution of the mixture is different in different operating conditions, and considering the lean combustion mode, the greater the dilution of the mixture, the lower the fuel consumption and the lower the original NOx emission, but it is more difficult to achieve stable combustion, therefore, the engine can be controlled to execute the first combustion mode or the second combustion mode according to the dilution of the mixture, so that when the dilution of the mixture is high, i.e. the lean gas is sufficient, the engine is controlled to execute the second combustion mode, i.e. the main combustion chamber is controlled to operate in the lean mode, so as to reduce the fuel consumption of the engine, improve the thermal efficiency, and control the pre-combustion chamber to operate in the active pre-combustion mode, so that the first fuel injector sprays oil and the first spark plug ignites to achieve multi-point ignition in the main combustion chamber, improve the combustion rate of the main combustion chamber, reduce fuel consumption and NOx emission, improve the performance-price ratio, and realize local rich mixture in the pre-combustion chamber to improve the stability of lean ignition; on the contrary, when the dilution of the mixture is low, i.e. the lean gas is insufficient, the engine is controlled to execute the first combustion mode to avoid the problem of increasing the original NOx emission due to the decrease of the NOx conversion efficiency of the three-way catalytic converter in the lean mode, and reduce the aftertreatment cost.

[0120] In some embodiments, after determining that the engine is in a normal operating condition, the dilution of the mixture λ0 is obtained, such as the dilution of the mixture λ0 can be the average dilution of the mixture in the cylinder of the engine or the dilution of the mixture monitored by the oxygen sensor before the exhaust, wherein the dilution of the mixture λ0 is the ratio of the actual amount of air in the combustion chamber of the engine to the amount of air required for complete combustion of the gas. Then, during the operation of the engine, if the dilution of the mixture λ0 meets the first dilution range of the mixture, the engine is controlled to execute the first combustion mode, wherein the first dilution range of the mixture can be understood as the range of the dilution of the mixture when the main combustion chamber operates in the stoichiometric mode, which is a pre-set range, or if the dilution of the mixture λ0 meets the second dilution range of the mixture, the engine is controlled to execute the second combustion mode, wherein the second dilution range of the mixture can be understood as the range of the dilution of the mixture when the main combustion chamber operates in the lean mode, which is a pre-set range. Therefore, by determining the target operating mode according to the dilution of the mixture λ, the emission of harmful gas and fuel consumption can be effectively reduced, and the output torque and output power of the engine can be improved.

[0121] In some embodiments, under the second combustion mode, when the pre-combustion chamber is operating in active pre-combustion mode, the local mixture dilution λ1 at the first spark plug in the pre-combustion chamber is controlled to meet the local mixture dilution range. Specifically, when the main combustion chamber is operating in lean-burn mode, in order to ensure a certain mixture dilution to reduce NOx emissions, the second mixture dilution range is large, the ignition stability is low, and the combustion speed is slow. Therefore, the active pre-combustion mode is combined with the lean-burn mode. Thus, in lean-burn mode, by controlling the first injector to perform micro-injection in the pre-combustion chamber, a locally rich mixture is formed at the electrode position of the first spark plug in the pre-combustion chamber at the ignition moment. That is, the local mixture dilution λ1 at the first spark plug in the pre-combustion chamber is controlled to meet the local mixture dilution range, thereby improving ignition stability, increasing combustion speed, and expanding the upper limit of mixture dilution for stable combustion.

[0122] For example, see reference. Figure 7 As shown, with the electrode position of the first spark plug as the center, within a spherical region with a preset radius of 4 mm, at the moment of ignition, when the local mixture dilution λ1 meets the local mixture dilution range, the volume ratio of the mixture will be greater than or equal to a certain volume ratio, such as 70%, in order to ensure the ignition stability and combustion speed in lean-burn mode.

[0123] In some embodiments, the first mixture dilution range is 0.7≤λ0≤1.3, preferably λ0=1, that is, when the mixture dilution λ0=1, the engine is controlled to execute the first combustion mode; the second mixture dilution range is λ0≥2, that is, when the mixture dilution satisfies λ0≥2, the engine is controlled to execute the second combustion mode; the local mixture dilution range is 0.7≤λ1≤1.1.

[0124] Furthermore, it should be noted that the engine operates in two states: stoichiometric combustion mode (where the air-fuel mixture dilution meets the first dilution range, such as λ0 = 1) or lean-burn mode (where the air-fuel mixture dilution meets the second dilution range, λ0 ≥ 2). This excludes the switching process between the two combustion modes from λ0 = 1 to λ0 ≥ 2. Figure 8 During the switching time t, operation should be avoided when the mixture dilution is 1 < λ0 < 2 in other cases to reduce NOx emissions. Furthermore, during combustion mode switching between λ0 = 1 and λ0 ≥ 2, for example, switching from λ0 ≥ 2 to λ0 = 1, the mixture dilution λ0 directly switches from λ0 ≥ 2 to λ0 = 1. However, in practical applications, due to hardware transition time, there is actually a transition time t during the switching process. Within this transition time t, λ0 will be in the range of 1 < λ0 < 2. This transition time should be minimized as much as possible to reduce NOx emissions.

[0125] Specifically, refer to Figure 6and Figure 8 As shown, when the engine's operating conditions change continuously at the intersection of region 1 and region 2, it will simultaneously switch between lean-burn mode and stoichiometric combustion mode, that is, switch between λ0=1 and λ0≥2; and, when the engine is in normal operating condition, it will switch between lean-burn mode and stoichiometric combustion mode. Figure 6 In region 2, if the engine operates in lean-burn mode for an extended period, requiring NOx aftertreatment, it will switch to stoichiometric combustion mode. Except for the two scenarios mentioned above, the two modes will not continuously switch. When switching from lean-burn to stoichiometric combustion mode, the turbocharger, throttle, and VVT responsiveness are calibrated to complete the switch within five cycles, from λ0≥2 to λ0=1. Furthermore, if the engine is continuously operating at the boundary between regions 1 and 2, frequent switching between lean-burn and stoichiometric combustion modes will occur due to the engine being in a non-steady state. To address this, a transition zone can be set at the boundary, such as setting the engine speed ±100 rpm or the engine's mean effective braking pressure ±1 bar as the transition zone. Within this transition zone, the mixture dilution λ0 will not switch, thus avoiding frequent mode switching.

[0126] Furthermore, for the case where the mixture dilution is 1 < λ0 < 2 during the switching process between the two combustion modes from λ0 = 1 to λ0 ≥ 2, since this is a transient process, additional calibration can be performed. For example, when λ0 is greater than 1.3, the engine can be controlled to operate in active pre-combustion mode; when λ0 is greater than 1.3, the engine can be controlled to operate in passive pre-combustion mode.

[0127] Therefore, by matching the passive pre-combustion mode, active pre-combustion mode, lean combustion mode and stoichiometric combustion mode, the operating range of λ0 > 2, i.e. the normal operating condition, covers the engine's conventional operating conditions, avoiding frequent switching between λ0 = 1 and λ0 > 2, and reducing the problem of increased NOx emissions caused by mode switching.

[0128] In some embodiments, a second spark plug is provided in the main combustion chamber, and the multiple combustion modes also include a third combustion mode, wherein the main combustion chamber adopts an equivalence ratio combustion mode and the second spark plug is ignited.

[0129] In the embodiments, when the main combustion chamber is equipped with a second spark plug, when the engine is under high load or normal operating conditions, the first spark plug can be controlled to ignite for auxiliary ignition, thereby improving ignition stability and reducing knocking, or the first spark plug can be controlled not to ignite, and there is no limitation on this.

[0130] Further, in determining the operating condition of the engine according to the rotation speed and the load, if the rotation speed is less than the first preset rotation speed v1 and the load is less than the third preset load threshold Z3, or the rotation speed is greater than the first preset rotation speed v1 and the load is less than the first preset load threshold Z1, it is determined that the engine is in the cold start operating condition or the catalyst heating condition, for example, Figure 6 The shadow area divided by the number 3 in the figure is the range of the pre-divided cold start operating condition or catalyst heating condition. Further, after determining that the engine is in the cold start operating condition or the catalyst heating condition, the engine is controlled to execute the third combustion mode, that is, the main combustion chamber is controlled to operate in the equivalent ratio combustion mode, and the second spark plug is ignited to solve the risk of unstable combustion of the pre-combustion chamber of the engine in the cold start operating condition or the catalyst heating condition, and to improve the knock and increase the combustion speed by increasing the ignition source. In the third combustion mode, the pre-combustion chamber can be controlled not to operate, or the pre-combustion chamber can be controlled to operate in the passive pre-combustion mode, that is, the first spark plug is ignited to assist ignition and improve ignition stability.

[0131] In summary, according to the control method of the engine of the embodiment of the present application, different operating conditions of the engine are divided to adopt different combustion modes for different operating conditions, and the advantages of the active pre-combustion mode and the passive pre-combustion mode are applied, so that the fuel consumption and NOx emission of the whole machine can be effectively reduced, and the output torque and output power of the engine can be improved. In addition, the calculation model of the single-cycle intake amount and the single-cycle fuel injection amount in the pre-combustion chamber is designed, so that the fuel injection amount in the pre-combustion chamber can be accurately controlled, the concentration of the local mixture at the first spark plug can be controlled, the PN emission can be reduced, the risk of depositing carbon in the injection hole in the pre-combustion chamber can be reduced, and the wet wall and combustion stability in the pre-combustion chamber can be improved.

[0132] The third embodiment of the present application provides a vehicle, as shown in the figure, the vehicle 1000 comprises an engine 900, an engine controller 2 and a memory 3 connected with the engine controller 2. Figure 9

[0133] The memory 3 stores a computer program executable by the engine controller 2, and the engine controller 2 executes the computer program to realize the pre-combustion chamber fuel injection calculation method or the control method of the engine provided by the above-mentioned embodiments.

[0134] It should be noted that the specific implementation mode of the engine controller 2 of the embodiment of the present application is similar to that of the pre-combustion chamber fuel injection calculation method or the control method of the engine of any of the above-mentioned embodiments of the present application, and the specific implementation mode is described in the method part, and in order to reduce redundancy, it will not be described here.

[0135] ​According to the vehicle 1000 of the embodiment of the present application, by using the pre-combustion chamber fuel injection calculation method or the engine control method provided by the above-mentioned embodiments by the engine controller 2, accurate control of the pre-combustion chamber fuel injection amount can be achieved, ignition stability can be improved, and problems such as pre-combustion chamber carbon deposition, high emissions, and insufficient pre-combustion chamber energy release can be reduced.

[0136] The fourth aspect of the present application provides a computer storage medium having a computer program stored thereon, wherein the computer program is executed by a processor to implement the pre-combustion chamber fuel injection calculation method or the engine control method provided by the above-mentioned embodiments.

[0137] In the description of the present specification, any process or method described in the flowchart or otherwise described herein can be understood as representing a module, a segment or a portion of code including one or more executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of the present application includes additional implementations in which the functions can be performed in an order other than that shown or discussed, including in a substantially simultaneous manner according to the functions involved or in a reverse order, which should be understood by those skilled in the art to which the embodiments of the present application belong.

[0138] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a list of executable instructions for implementing logic functions, which can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus or device, such as a computer-based system, a system including a processor or other system that can fetch instructions from an instruction execution system, apparatus or device and execute the instructions. For the purposes of the present specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transport a program for use by or in connection with an instruction execution system, apparatus or device or in conjunction with these instruction execution systems, apparatus or devices. More specific examples (non-exhaustive list) of computer-readable medium include the following: electrical connections having one or more wires (electronic devices), portable computer diskette (magnetic devices), random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), fiber optic devices, and portable compact disc read-only memory (CD ROM). In addition, the computer-readable medium can even be paper or other suitable medium on which the program can be printed, as the program can be electronically obtained, for example, by optical scanning of the paper or other medium, followed by electronic conversion of the obtained program into a computer-readable medium, and then storing the program in a computer memory if necessary. The program can be processed before storage in the computer memory, for example, by editing, interpreting or necessary processing, or in other suitable ways.

[0139] It should be understood that aspects of the application can be implemented in hardware, software, firmware or a combination of them. In the above embodiments, various steps or methods can be implemented in software or firmware that is stored in memory and executed by a suitable instruction execution system. As such, in some embodiments, specifically tailored hard-wired circuitry can be used in place of, or in combination with, software instructions for implementation of the methods described above, as can be suitable for that or an alternative embodiment. For example, any of the following can be used to implement one or both of the above-described embodiments, either alone or in combination: discrete logic circuitry having logic gates for implementing logic functions upon an application of data signals, application-specific integrated circuits having appropriate combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), and so forth.

[0140] Those skilled in the art can understand that all or part of the steps of the above-mentioned embodiment method can be completed by programs instructing relevant hardware, and the programs can be stored in a computer readable storage medium, and when the programs are executed, one or a combination of the steps of the method embodiment is included.

[0141] In addition, each functional unit in each embodiment of the present application can be integrated into one processing module, or each unit can exist physically separately, or two or more units can be integrated into one module. The integrated module can be realized in the form of hardware or in the form of a software functional module. When the integrated module is realized in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer readable storage medium.

[0142] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

[0143] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily mean the same embodiment or example.

[0144] Although the embodiments of the present application have been shown and described above, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

Claims

1. A precombustion chamber fuel injection calculation method characterized by comprising: The application relates to a calculation method for an engine, the engine comprising an engine combustion chamber, the engine combustion chamber comprising a main combustion chamber and a precombustion chamber, the calculation method comprising: obtaining a total intake mass of the engine combustion chamber per cycle; obtaining an intake amount of the precombustion chamber per cycle according to a total volume value of the engine combustion chamber, a volume value of the precombustion chamber and the total intake mass of the engine combustion chamber per cycle; correcting the intake amount of the precombustion chamber per cycle according to an engine current working condition, the engine current working condition comprising one or more of a rotating speed, a crank angle, a load, an intake temperature and an intake and exhaust valve opening / closing phase, to obtain a corrected intake amount of the precombustion chamber per cycle; obtaining an injection amount of the precombustion chamber per cycle according to a theoretical air-fuel ratio and the corrected intake amount of the precombustion chamber per cycle; obtaining an injection pulse width of the precombustion chamber per cycle according to the injection amount of the precombustion chamber per cycle; wherein the correcting the intake amount of the precombustion chamber per cycle according to the engine current working condition, to obtain the corrected intake amount of the precombustion chamber per cycle, comprises: determining a first correction coefficient according to the crank angle; determining a second correction coefficient according to the rotating speed and the load; determining a third correction coefficient according to the intake temperature and the intake and exhaust valve opening / closing phase; correcting the intake amount of the precombustion chamber per cycle according to the first correction coefficient, the second correction coefficient and the third correction coefficient, to obtain the corrected intake amount of the precombustion chamber per cycle.

2. The pre-combustion chamber fuel injection calculation method according to claim 1, characterized by, The obtaining the total intake mass of the engine combustion chamber per cycle comprises: obtaining the total intake mass of the engine combustion chamber per cycle according to the engine current working condition, wherein the engine current working condition further comprises an intake pressure, a residual exhaust pressure in a cylinder after the intake valve and the exhaust valve are closed and a volume value of the engine per cylinder at a time when the intake valve is closed.

3. The pre-combustion chamber fuel injection calculation method according to claim 1, characterized by, The correcting the intake amount of the precombustion chamber per cycle according to the first correction coefficient, the second correction coefficient and the third correction coefficient, to obtain the corrected intake amount of the precombustion chamber per cycle, comprises: obtaining the corrected intake amount of the precombustion chamber per cycle by the following formula: wherein m0 is the single-cycle intake amount of the pre-combustion chamber after correction, is the single-cycle intake amount of the pre-combustion chamber, is the first correction coefficient, is the second correction coefficient, is the third correction coefficient.

4. The pre-combustion chamber fuel injection calculation method according to claim 1, characterized by, The obtaining the injection pulse width of the precombustion chamber per cycle according to the injection amount of the precombustion chamber per cycle comprises: correcting the injection amount of the precombustion chamber per cycle according to the engine current working condition, to obtain a corrected injection amount of the precombustion chamber per cycle, wherein the engine current working condition further comprises an injection time of the precombustion chamber and an ignition time of the precombustion chamber; obtaining the injection pulse width of the precombustion chamber per cycle according to the corrected injection amount of the precombustion chamber per cycle.

5. The pre-combustion chamber fuel injection calculation method according to claim 4, characterized by, The correcting the injection amount of the precombustion chamber per cycle according to the engine current working condition, to obtain the corrected injection amount of the precombustion chamber per cycle, wherein the engine current working condition further comprises the injection time of the precombustion chamber and the ignition time of the precombustion chamber, comprises: determining a fourth correction coefficient according to the rotating speed and the load; determining a fifth correction coefficient according to the injection time and the ignition time; The single-cycle fuel injection quantity of the pre-combustion chamber is corrected according to the fourth correction coefficient and the fifth correction coefficient to obtain a corrected single-cycle fuel injection quantity of the pre-combustion chamber.

6. The pre-combustion chamber fuel injection calculation method according to claim 5, characterized by, The single-cycle fuel injection quantity of the pre-combustion chamber is corrected according to the fourth correction coefficient and the fifth correction coefficient to obtain a corrected single-cycle fuel injection quantity of the pre-combustion chamber, including: The corrected single-cycle fuel injection quantity of the pre-combustion chamber is obtained by the following formula: wherein, is the single-cycle fuel injection amount of the precombustion chamber after correction, is the single-cycle fuel injection amount of the precombustion chamber, is the fourth correction coefficient, is the fifth correction coefficient; The single-cycle fuel injection quantity of the pre-combustion chamber is obtained according to the theoretical air-fuel ratio and the corrected single-cycle intake air quantity of the pre-combustion chamber, including: The single-cycle fuel injection quantity of the pre-combustion chamber is obtained by the following formula: wherein m0 is the corrected single-cycle intake air amount of the pre-chamber, is the theoretical air-fuel ratio.

7. The pre-combustion chamber fuel injection calculation method according to any one of claims 1-6, characterized in that, The single-cycle intake air quantity of the pre-combustion chamber is obtained according to the total volume value of the engine combustion chamber, the volume value of the pre-combustion chamber and the single-cycle total intake air mass of the engine combustion chamber, including: The single-cycle intake air quantity of the pre-combustion chamber is obtained by the following formula: wherein, is the single cycle intake mass of the pre-combustion chamber, is the total intake mass of the engine combustion chamber for a single cycle, is the volume value of the pre-combustion chamber, is the total volume value of the engine combustion chamber.

8. A control method of an engine characterized by comprising: including: determining the operating condition of the engine according to the engine speed and the load; selecting a combustion mode from a plurality of combustion modes according to the operating condition of the engine, wherein the plurality of combustion modes include a first combustion mode and a second combustion mode, the first combustion mode is that the main combustion chamber adopts an equivalent ratio combustion mode and the pre-combustion chamber adopts a passive pre-combustion mode, the second combustion mode is that the main combustion chamber adopts a lean combustion mode and the pre-combustion chamber adopts an active pre-combustion mode, in the active pre-combustion mode, the fuel injection pulse width of the pre-combustion chamber is calculated according to the pre-combustion chamber fuel injection calculation method of any one of claims 1-7; controlling the engine to execute the selected combustion mode.

9. The engine control method according to claim 8, characterized in that, the determining the operating condition of the engine according to the engine speed and the load includes: if the engine speed is greater than a first preset engine speed and less than a second preset engine speed, and the load is greater than a first preset load threshold and less than a second preset load threshold, or the load is equal to a maximum allowable load threshold, it is determined that the engine is in a high load operating condition; if the engine speed is less than the first preset engine speed, and the load is greater than a third preset load threshold and less than the maximum allowable load threshold, or the engine speed is greater than the first preset engine speed and less than the second preset engine speed, and the load is greater than the second preset load threshold and less than the maximum allowable load threshold, or the engine speed is greater than the second preset engine speed, and the load is greater than the first preset load threshold and less than the maximum allowable load threshold, it is determined that the engine is in a normal operating condition, wherein the first preset engine speed < the second preset engine speed, the first preset load threshold < the third preset load threshold < the second preset load threshold < the maximum allowable load threshold; the selecting a combustion mode from a plurality of combustion modes according to the operating condition of the engine includes: if the engine is in the high load operating condition, the first combustion mode is selected; If the engine is in the normal operation condition, the first combustion mode or the second combustion mode is selected.

10. The control method of an engine according to claim 9, characterized by If the engine is in the normal operation condition, the first combustion mode or the second combustion mode is selected, comprising: After determining that the engine is in the normal operation condition, a mixture dilution degree λ0 is obtained; If the mixture dilution degree λ0 meets a first mixture dilution degree range, the first combustion mode is selected; If the mixture dilution degree λ0 meets a second mixture dilution degree range, the second combustion mode is selected, wherein, in the second combustion mode, when the precombustion chamber is controlled to operate in the active precombustion mode, a local mixture dilution degree λ1 at a first spark plug in the precombustion chamber meets a local mixture dilution degree range.

11. The control method of an engine according to claim 10, characterized by The first mixture dilution degree range is 0.7≤λ0≤1.3, the second mixture dilution degree range is λ0≥2, and the local mixture dilution degree range is 0.7≤λ1≤1.

1.

12. The control method of an engine according to claim 9, characterized by The main combustion chamber is provided with a second spark plug, and the plurality of combustion modes further includes a third combustion mode, the third combustion mode is that the main combustion chamber adopts an equivalent ratio combustion mode, and the second spark plug ignites, The determining of the operation condition of the engine according to the speed and the load further comprises: If the speed is less than the first preset speed and the load is less than a third preset load threshold, or the speed is greater than the first preset speed and the load is less than the first preset load threshold, it is determined that the engine is in a cold start operation condition or a catalyst heating condition; The selecting of the combustion mode from the plurality of combustion modes according to the operation condition of the engine further comprises: If the engine is in the cold start operation condition or the catalyst heating condition, the third combustion mode is selected.

13. A vehicle characterized by comprising: Comprise: An engine and an engine controller; A memory in communication connection with the engine controller; The memory stores a computer program executable by the engine controller, and the engine controller executes the computer program to implement the precombustion chamber fuel injection calculation method of any one of claims 1-7 or the engine control method of any one of claims 8-12.

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