Engine and control method, electronic device, storage medium, vehicle

Abstract

An engine and control method, electronic device, storage medium, and vehicle, wherein the control method includes: obtaining an engine operating condition; obtaining an alcohol ratio in the engine; determining a fuel injection mode and injection ratio based on the operating condition and the alcohol ratio; controlling engine operation based on the fuel injection mode and injection ratio; determining the injection mode to be a direct injection mode; determining the injection mode to be a dual injection mode and determining the injection ratio to be a first injection ratio; determining the injection mode to be a dual injection mode and determining the injection ratio to be a second injection ratio; determining the injection mode to be a dual injection mode and determining the injection ratio to be a third injection ratio. This application can alleviate the problems of cold start difficulty, poor low-temperature operating performance, knock, and pre-ignition that arise when using only port injection mode, as well as the problems of insufficient injection duration and high rail pressure corrosion that arise when using only direct injection mode.

Description

Technical Field

[0001] The present application relates to the field of engine technology, and in particular to an engine and control method, electronic equipment, storage medium, and vehicle. Background Art

[0002] An alcohol fuel engine is an engine that uses alcohol (such as methanol, ethanol or butanol) or a fuel blended with alcohol for energy. When using multiple alcohols and their mixed fuels at the same time, such an engine is also called a "flexible alcohol engine" or "elastic alcohol engine".

[0003] In alcohol-fueled engines, fuel injection is typically performed using either port injection or direct injection. Port injection facilitates high-flow injection of fuels with high alcohol content, offers low injection pressure, and reduces corrosion. However, alcohol-fueled engines using port injection alone and fuels with high alcohol content may experience cold-start difficulties, requiring the addition of a preheating device or a dedicated cold-start gasoline supply system. Furthermore, when using fuels with low alcohol content, pre-ignition becomes a prominent issue, limiting low- and medium-speed power and requiring a lower compression ratio, further reducing engine efficiency.

[0004] The direct injection mode is beneficial to the cold start and low-temperature operation of alcohol flexible fuels. However, when the alcohol fuel engine adopts the direct injection mode alone, the required injection pressure and injection duration continue to increase with the increase of load. The problem is that the injection cycle of direct injection is too long, and fuel can only be injected during the intake and compression strokes, which can easily cause problems such as wall wetting and poor atomization. The injection duration is limited, and the rail pressure is high, and the corrosion problem is more serious. If the rail pressure is reduced, the injection time will be further extended, and the high-speed power output will be limited. It is necessary to develop larger flow and corrosion-resistant injectors and oil pumps, which leads to increased engine development costs. Summary of the Invention

[0005] In view of the above, it is necessary to provide an engine and control method, electronic equipment, storage medium, and vehicle that can achieve flexible matching of injection control according to the composition characteristics and operating conditions of flexible alcohol fuel, thereby reducing the problems of cold start difficulty, poor low-temperature operating performance, detonation and pre-ignition that exist when using the intake port injection mode alone, and reducing the problems of insufficient injection duration and high rail pressure corrosion that exist when using the direct injection mode alone.

[0006] The first aspect of the present application provides an engine control method, comprising: obtaining the operating condition of the engine; obtaining the alcohol ratio in the engine; determining the fuel injection mode and injection ratio based on the operating condition and the alcohol ratio; and controlling the engine operation based on the fuel injection mode and the injection ratio; wherein the operating condition includes at least the load, temperature and start-stop state of the engine, the alcohol ratio is defined as the ratio of the content of flexible alcohol to the content of fuel, the injection mode includes the direct injection mode, the intake port injection mode and the dual injection mode, and the injection ratio is defined as the ratio of the fuel injection amount in the direct injection mode to the fuel injection amount in the intake port injection mode; determining the fuel injection mode and the injection ratio based on the operating condition and the alcohol ratio, comprising: when the load is less than a predetermined load value, the temperature is less than a preset temperature value, or the start-stop state is start, determining the injection mode to be the direct injection mode. Formula; when the load is greater than the predetermined load value and the alcohol ratio is close to the maximum value, the injection mode is determined to be the dual injection mode, and the injection ratio is determined to be the first injection ratio, wherein the first injection ratio is defined as a ratio when the fuel injection amount in the direct injection mode is less than the fuel injection amount in the port injection mode; when the load is greater than the predetermined load value and the alcohol ratio is close to the minimum value, the injection mode is determined to be the dual injection mode, and the injection ratio is determined to be the second injection ratio, wherein the second injection ratio is defined as a ratio when the fuel injection amount in the direct injection mode is greater than the fuel injection amount in the port injection mode; when the load is greater than the predetermined load value and the alcohol ratio is between the minimum value and the maximum value, the injection mode is determined to be the dual injection mode, and the injection ratio is determined to be the third injection ratio, wherein the third injection ratio is between the first injection ratio and the second injection ratio.

[0007] In the control method of the present application, the predetermined load value can be used as a definition of whether the engine load is in a low-load working condition, and the preset temperature value can be used as a definition of whether the engine temperature is in a low-temperature working condition. At this time, the load is less than the predetermined load value, that is, the engine is in a low-load working condition, and the temperature is less than the preset temperature value, that is, the engine is at a low temperature. When the start-stop state is start, the injection mode is determined to be the direct injection mode. The engine operates in the direct injection mode, and can accurately control the injection amount and achieve good fuel atomization and oil-gas mixing under any alcohol ratio, thereby achieving good starting performance, low-load fuel consumption and emission control.

[0008] In addition, when the load is greater than the predetermined load value and the alcohol ratio is close to the maximum value, at this time, the alcohol content in the engine fuel is relatively high, and the engine operates in a medium and above load range. Therefore, it is determined that the injection mode to be adopted by the engine is the dual injection mode, and the injection ratio is determined to be the first injection ratio in which the fuel injection amount in the direct injection mode is less than the fuel injection amount in the intake port injection mode. In this case, the octane number of the fuel is higher, and the tendency to knock and pre-ignition is low. If the specific working area of ​​the engine is a large load, a larger proportion of the intake port injection mode is used, and a certain proportion of direct injection is used for fuel injection. Since the injection amount of direct injection in the cylinder is relatively small, the rail pressure of the direct injection mode can be maintained at a relatively low level, and the injection duration is relatively controllable, and the injection phase can be optimized according to fuel consumption and emissions.

[0009] In addition, when the load is greater than the predetermined load value and the alcohol ratio is close to the minimum value, at this time, the alcohol content in the engine's fuel is low, and the engine operates in a medium and above load area, so the injection mode is determined to be a dual injection mode, and the injection ratio is determined to be a second injection ratio in which the fuel injection amount in the direct injection mode is greater than the fuel injection amount in the intake port injection mode. If the engine operates in a medium-low speed, high load, strong knock and prone to pre-ignition area, the direct injection mode can be used, and a small proportion of intake port injection can be added or intake port injection can be not used based on subsequent calibration performance, so as to solve the knock and pre-ignition problems and improve the engine's power output; if the engine operates above medium load and in a medium-high speed area, a certain proportion of intake port injection can be added on the basis of the direct injection mode, so that the engine can achieve high power output under good conditions of direct injection injection duration and injection timing.

[0010] In addition, when the load is greater than the predetermined load value and the alcohol ratio is between the minimum value and the maximum value, at this time, the alcohol content in the engine's fuel is between low and high, and the engine operates in a load area of ​​medium intensity and above. Therefore, the injection mode is determined to be a dual injection mode, and the injection ratio is determined to be a third injection ratio between the first injection ratio and the second injection ratio, that is, the third injection ratio is a non-fixed value. In this case, if the specific working area of ​​the engine is a medium load, the appropriate third injection ratio can be determined through subsequent calibration optimization to reduce various problems caused by the use of direct injection in the cylinder alone or intake port injection alone.

[0011] In some embodiments, the operating conditions also include the engine speed; the fuel injection mode and injection ratio are determined based on the operating conditions and the alcohol ratio, including: when the load is greater than a predetermined load value, the alcohol ratio is close to the minimum value, and the speed is less than a predetermined speed, the injection mode is determined to be a dual injection mode, and the injection ratio is determined to be the second injection ratio; when the load is greater than a predetermined load value, the alcohol ratio is close to the minimum value, and the speed is greater than a predetermined speed, the injection mode is determined to be a dual injection mode, and the injection ratio is determined to be a fourth injection ratio; wherein the fourth injection ratio is between the second injection ratio and the third injection ratio.

[0012] In some embodiments, determining the injection ratio includes: if the alcohol ratio is close to a minimum value, using 1:0 as an initial injection ratio, and increasing the fuel injection amount in the intake port injection mode by a first preset increment to obtain multiple injection ratios; if the alcohol ratio is close to a maximum value, using 0:1 as an initial injection ratio, and increasing the fuel injection amount in the direct injection mode by a second preset increment to obtain multiple injection ratios; calibrating the operating conditions with the multiple injection ratios, wherein the calibration is related to the engine speed, injection timing, and allowable rail pressure.

[0013] In some embodiments, determining the injection ratio also includes: calculating the median of the alcohol ratio, using the predicted value of the direct injection ratio in the cylinder under the median as the initial injection ratio, and increasing or decreasing the fuel injection amount in the direct injection mode by a third preset increment to obtain multiple injection ratios, wherein the median is equal to the sum of the maximum value and the minimum value divided by 2; and calibrating the operating conditions with the multiple injection ratios.

[0014] In some embodiments, determining the injection ratio further includes: obtaining an initial calibration curve based on a maximum value, a median value, and a minimum value; increasing or decreasing the content of the flexible alcohol by a fourth preset increment to obtain multiple alcohol ratios; and interpolating and optimizing the multiple alcohol ratios with the initial calibration curve to obtain a final calibration curve.

[0015] In some embodiments, the control method further includes: acquiring an oxygen content of the engine, and obtaining an air-fuel ratio of the engine based on the oxygen content; and re-acquiring an alcohol ratio in the engine based on the air-fuel ratio.

[0016] In some embodiments, controlling engine operation based on the fuel injection mode and injection ratio includes: controlling at least one of the engine's injection pressure, injection amount, injection timing, intake and exhaust, or ignition combustion based on the fuel injection mode and injection ratio.

[0017] In some embodiments, controlling the engine operation based on the fuel injection mode and injection ratio also includes: obtaining the model output torque and target output torque of the engine, wherein the model output torque is defined as the actual output torque of the engine based on the fuel injection mode and injection ratio, and the target output torque is defined as the theoretical output torque of the engine based on the fuel injection mode and injection ratio; if the model output torque is less than the target output torque, then re-controlling at least one of the engine's injection pressure, injection amount, injection timing, intake and exhaust, or ignition combustion based on the fuel injection mode and injection ratio.

[0018] The second aspect of the present application provides an engine, including a control device, an engine body, an intake system, a fuel supply system and an exhaust after-treatment system; the control device is connected to the engine body, the intake system, the fuel supply system and the exhaust after-treatment system, and is used to execute the control method of any embodiment of the first aspect of the present application to control the engine; the fuel supply system includes a first sensor for detecting the alcohol content; the exhaust after-treatment system includes a second sensor for detecting the oxygen content.

[0019] A third aspect of the present application provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the engine control method of any embodiment of the first aspect of the present application.

[0020] A fourth aspect of the present application provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the engine control method of any embodiment of the first aspect of the present application.

[0021] A fifth aspect of the present application provides a vehicle, the vehicle includes an engine, the engine includes a control device, and the control device is used to execute the engine control method of any embodiment of the first aspect of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flowchart of the engine control method of an embodiment of the present application.

[0023] Figure 2 It is a flowchart of the calibration process of step S300 in an embodiment of the present application.

[0024] Figure 3 It is a flowchart of the calibration process of another embodiment of step S300 of the embodiment of the present application.

[0025] Figure 4 This is a flowchart of a calibration process of another embodiment of step S300 of the embodiment of the present application.

[0026] Figure 5 It is a sub-flowchart of step S400 of an embodiment of the present application.

[0027] Figure 6 This is a flowchart of another embodiment of the engine control method of the embodiment of the present application.

[0028] Figure 7 It is a structural block diagram of the engine of an embodiment of the present application.

[0029] Description of main component symbols

[0030] 1. Engine; 11. Control device; 12. Engine body; 13. Intake system; 14. Fuel supply system; 15. Exhaust after-treatment system; 141. Direct injection subsystem; 142. Port injection subsystem.

[0031] The following specific implementation mode will further illustrate this application in conjunction with the above-mentioned drawings.

[0032] Specific implementation mode

[0033] In the description of the embodiments of this application, words such as "exemplary," "or," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary," "or," and "for example" is intended to present related concepts in a specific manner.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs. The terms used in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. It should be understood that, unless otherwise specified in this application, " / " means or. For example, A / B can mean A or B. "And / or" in this application is merely a way to describe the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. "At least one" means one or more. "Multiple" means two or more than two. For example, at least one of a, b or c can mean: a, b, c, a and b, a and c, b and c, a, b and c.

[0035] It should also be noted that the terms "first" and "second" in the specification, claims, and drawings of this application are used to distinguish similar objects, rather than to describe a specific order or sequence. The methods disclosed in the embodiments of this application or the methods shown in the flowcharts include one or more steps for implementing the methods. Without departing from the scope of the claims, the order of execution of multiple steps can be interchanged with each other, and some steps can also be deleted.

[0036] Amid the global trend toward low-carbonization, low-carbon fuels such as ethanol and methanol are being widely promoted in many regions. Currently, the market offers pure gasoline, ethanol, methanol, other alcohols, and flexible alcohol fuels. Flexible alcohol fuels, also known as flexible alcohol fuels, are blended with gasoline using ethanol, methanol, or other alcohols. Alcohol-fueled engines, defined as engines powered by alcohols or fuels blended with alcohols, are also referred to as "flexible alcohol engines" or "flexible alcohol engines" when they use multiple alcohols or their blends.

[0037] Fuels with different alcohol ratios have significantly different characteristics, with varying advantages and disadvantages. This leads to significant differences in engine performance under different operating conditions. Specifically, when the alcohol content in an alcohol fuel is low, the octane number is low, the fuel's knock resistance is poor, and the tendency to pre-ignition is high, affecting the engine's low- and medium-speed power output. This also makes it unsuitable for increasing cycle thermal efficiency through a higher compression ratio. The advantage of a low alcohol content in an alcohol fuel is relatively low corrosiveness, which reduces the requirements for corrosion-resistant materials and allows the engine to use a higher rail pressure. Another advantage is better cold-start performance. When the alcohol content is high, the advantages are higher knock resistance and a lower tendency to pre-ignition, allowing the engine to achieve high power and good combustion phasing at low and medium speeds. However, there are the disadvantages of low calorific value, large injection volumes, and long injection durations, which can lead to wall wetting, oil dilution, deteriorating combustion emissions, and poor fuel volatility, which can significantly affect cold-starting. Furthermore, when the alcohol content is high, the corrosiveness is high, and this problem becomes more prominent when the engine uses high rail pressure. Therefore, for flexible alcohol fuel engines that use any blending ratio, it is difficult to ensure that the values ​​remain reasonable and feasible when burning fuels of all alcohol ratios, and to maintain a high level of performance output. Therefore, targeted strengthening or improvement measures are needed to address the corresponding issues.

[0038] In alcohol-fueled engines in the related art, fuel injection generally uses either port injection or direct injection (DI). PI allows fuel injection throughout the entire cycle, resulting in a longer injection duration, which is advantageous for high-flow injection of fuels with a higher alcohol content. Furthermore, the injection pressure is lower, and corrosion issues are less prominent. However, when using PI alone in alcohol-fueled engines with high-alcohol fuels, the fuel mixes with air in the intake manifold, with some fuel adsorbed on the wall to form an oil film, making it difficult for the oil and air to mix fully. During cold starts and low-temperature operation, the difficulty of evaporating high-alcohol fuels causes more fuel to initially adsorb on the airway or valves, reducing the effective fuel-air mixture that can enter the cylinder in a timely manner. Consequently, fuel quantity control accuracy is low, which can easily lead to problems such as difficult cold starts, increased fuel consumption, and poor emissions. At the same time, when the engine is operating in the low- to medium-speed, high-load range, the large fuel injection volume makes the oil-air mixture more uneven, and there is no evaporation and heat absorption process after entering the cylinder. Therefore, the thermal load on the compression stroke is high, which is prone to detonation and pre-ignition, greatly limiting the engine's low- and medium-speed power output. In other words, the intake port injection mode has the problem of cold starting difficulties, requiring the addition of a preheating device or a dedicated cold start gasoline supply system. When using fuel with low alcohol content, pre-ignition is more prominent, limiting low- and medium-speed power, and requiring a lower compression ratio, further reducing engine efficiency.

[0039] In direct injection (DI), fuel is injected directly into the cylinder. By controlling multiple parameters, including injection pressure, jet shape, injection angle, and injection timing, the fuel-air mixing quality and fuel quantity control accuracy are significantly improved compared to port injection. This facilitates cold-start and low-temperature operation for alcohol-based flexible fuels, achieving excellent cold-start performance, low-temperature fuel economy, and emissions without the need for additional heating devices. Furthermore, because the evaporation of the injected fuel absorbs heat, it effectively reduces the in-cylinder temperature at the end of compression, thereby improving knock and pre-ignition at low and medium speeds and high loads. In this scenario, the engine can maintain high power output using a higher compression ratio and higher boost pressure. However, when using DI alone for alcohol-based engines, the required injection pressure and injection duration increase with increasing load. This leads to a long injection cycle, requiring injection only during the intake and compression strokes, which can easily cause wall wetting and poor atomization. This limits the injection duration, and the high rail pressure exacerbates corrosion issues, necessitating the development of specialized corrosion-resistant materials. If the rail pressure is reduced, the injection time will be further extended, which may easily limit the high-speed power output of the engine. It will be necessary to develop larger flow and corrosion-resistant injectors and oil pumps, which will easily lead to higher engine development costs.

[0040] In the related art, in order to solve the problems caused by using the direct injection mode or the intake manifold injection mode alone, there is also a dual injection mode that combines the direct injection mode and the intake manifold injection mode. However, this mode can only solve part of the above problems, such as pre-ignition or cold start difficulties. Other problems that seriously affect engine performance, such as corrosiveness and output efficiency, require the development of auxiliary devices with extremely complex structures, which is not conducive to reducing the development cost of the engine.

[0041] In summary, it is difficult to deal with all the above-mentioned prominent problems by using the direct injection mode, the intake port injection mode or the existing dual injection mode alone.

[0042] To this end, embodiments of the present application provide an engine and control method, electronic device, storage medium, and vehicle that can flexibly adapt injection control based on the compositional characteristics of flexible alcohol fuels and operating conditions. This reduces cold start difficulties, poor low-temperature performance, knock, and pre-ignition issues associated with port injection alone, as well as issues such as insufficient injection duration and high rail pressure corrosion associated with direct injection alone. Several embodiments are described below with reference to the accompanying drawings. The following embodiments and features therein may be combined unless otherwise noted.

[0043] Figure 1 It is a flowchart of the engine control method of an embodiment of the present application.

[0044] See also Figure 1 The present invention first provides an engine control method, which, for ease of description, will be referred to as "control method" or "method" below. The control method involved in the present invention may include:

[0045] Step S100: Acquire the engine operating condition.

[0046] The engine operating conditions include at least engine load, temperature, and start / stop status. Obtaining the engine operating conditions may include obtaining the current engine operating conditions and target engine operating conditions. The current operating conditions can be used to determine the engine's current operating state, such as whether it is towing a heavy load or whether the engine temperature has reached the operating temperature. The target operating conditions can be compared with the current operating conditions to determine whether engine control meets requirements, such as whether the engine's output torque has reached the target output torque.

[0047] In some embodiments, the engine operating conditions may also include speed, torque, or pressure.

[0048] In some embodiments, the current operating condition and the target operating condition may be determined based on current engine speed, accelerator pedal position, accelerator pedal change rate, vehicle speed, intake air temperature, intake air pressure, water temperature, oil temperature, or intake air temperature. In other embodiments, the current operating condition and the target operating condition may also be determined based on environmental information.

[0049] See also Figure 1 The control method involved in the embodiment of the present application may further include:

[0050] Step S200: Obtain the alcohol ratio in the engine.

[0051] The alcohol ratio is defined as the ratio of the flexible alcohol content to the fuel content. This information can be used to determine the composition of fuel. Specifically, an alcohol sensor measures the methanol or ethanol content in the fuel in real time, allowing the ratio of fuel alcohol to gasoline to be calculated. This information can then be used to estimate the fuel's density, calorific value, and estimated octane rating.

[0052] The flexible alcohols in the embodiments of the present application may include, but are not limited to, alcohol-based compounds such as methanol, ethanol, or butanol.

[0053] In the embodiments of the present application, the flexible alcohol content can be detected and obtained by an alcohol content sensor installed in the fuel supply system. Specifically, the flexible alcohol content can be detected and obtained by an alcohol content sensor installed at the inlet of the high-pressure fuel pump. In this case, the alcohol content sensor is placed at the inlet of the high-pressure fuel pump rather than in the fuel tank, which allows the alcohol content sensor to be closer to the fuel injection system. The resulting flexible alcohol content is more closely aligned with the characteristics of the fuel injected into the cylinder, thereby improving control accuracy.

[0054] See also Figure 1 The control method involved in the embodiment of the present application may further include:

[0055] Step S300: Determine the fuel injection mode and injection ratio based on the operating conditions and the alcohol ratio.

[0056] Among them, the injection mode includes direct injection mode, intake port injection mode and dual injection mode, and the injection ratio is defined as the ratio of the fuel injection amount in the direct injection mode to the fuel injection amount in the intake port injection mode.

[0057] Step S300 in the embodiment of the present application may specifically be:

[0058] When the load is less than a predetermined load value, the temperature is less than a preset temperature value, or the start-stop state is start, the injection mode is determined to be direct injection. In this case, the predetermined load value can be used to determine whether the engine load is in a low-load operating condition, and the preset temperature value can be used to determine whether the engine temperature is in a low-temperature operating condition. In this case, when the load is less than the predetermined load value, i.e., the engine is in a low-load operating condition, the temperature is less than the preset temperature value, i.e., the engine is in a low-temperature operating condition, and the start-stop state is start, the injection mode is determined to be direct injection. When the engine operates in direct injection mode, the fuel injection amount can be precisely controlled under any alcohol ratio, and good fuel atomization and oil-air mixing can be achieved, thereby achieving good starting performance, low-load fuel consumption, and emission control.

[0059] When the load is greater than a predetermined load value and the alcohol ratio is close to a maximum value, the injection mode is determined to be a dual injection mode, and the injection ratio is determined to be a first injection ratio, wherein the first injection ratio is defined as a ratio when the fuel injection amount in the direct injection mode is less than the fuel injection amount in the intake port injection mode. In this case, the predetermined load value can be used as a definition of whether the engine load is in a low-load condition. At this time, when the load is greater than the predetermined load value and the alcohol ratio is close to the maximum value, that is, the alcohol content in the engine fuel is high, the engine operates in a medium and above load range, so the injection mode to be adopted by the engine is determined to be the dual-injection mode, and the injection ratio is determined to be the first injection ratio in which the fuel injection amount in the direct injection mode is less than the fuel injection amount in the port injection mode. In this case, the octane number of the fuel is higher and the tendency to knock and pre-ignition is low. If the specific working area of ​​the engine is a high load, a larger proportion of the port injection mode is used, and a certain proportion of direct injection is used for fuel injection. Since the injection amount of direct injection in the cylinder is relatively small, the rail pressure of the direct injection mode can be maintained at a relatively low level, and the injection duration is relatively controllable, and the injection phase can be optimized according to fuel consumption and emissions.

[0060] When the load is greater than a predetermined load value and the alcohol ratio is close to a minimum value, the injection mode is determined to be a dual injection mode, and the injection ratio is determined to be a second injection ratio, wherein the second injection ratio is defined as a ratio when the fuel injection amount in the direct injection mode is greater than the fuel injection amount in the intake port injection mode. In this case, the predetermined load value can be used as a definition of whether the engine load is in a low-load condition. At this time, when the load is greater than the predetermined load value and the alcohol ratio is close to the minimum value, that is, the alcohol content in the engine fuel is low, and the engine operates in a medium or above load range, the injection mode is determined to be the dual injection mode, and the injection ratio is determined to be the second injection ratio in which the fuel injection amount in the direct injection mode is greater than the fuel injection amount in the port injection mode. If the engine operates in a medium-low speed, high load, strong knock and prone to pre-ignition area, the direct injection mode can be used, and a small proportion of port injection can be added or port injection can be not used based on subsequent calibration performance, so as to solve the knock and pre-ignition problems and improve the engine power output; if the engine operates above medium load and in a medium-high speed range, a certain proportion of port injection can be added on the basis of the direct injection mode, so that the engine can achieve high power output under good conditions of direct injection injection duration and injection timing.

[0061] When the load is greater than a predetermined load value and the alcohol ratio is between a minimum value and a maximum value, the injection mode is determined to be a dual-injection mode, and the injection ratio is determined to be a third injection ratio, where the third injection ratio is between the first and second injection ratios. In this case, the predetermined load value can be used to determine whether the engine load is in a low-load operating condition. In this case, when the load is greater than the predetermined load value and the alcohol ratio is between a minimum value and a maximum value, that is, the alcohol content in the engine fuel is between low and high, and the engine is operating in a medium-load or higher load range, the injection mode is determined to be a dual-injection mode, and the injection ratio is determined to be a third injection ratio between the first and second injection ratios, that is, the third injection ratio is a non-fixed value. In this case, if the specific engine operating range is medium load, a suitable third injection ratio can be determined through subsequent calibration optimization to reduce various problems caused by using direct injection or port injection alone.

[0062] Optionally, when the load is greater than a predetermined load value, the alcohol ratio is close to a minimum value, and the speed is less than a predetermined speed, the injection mode is determined to be the dual-injection mode, and the injection ratio is determined to be the second injection ratio. In this case, the predetermined load value can be used to determine whether the engine load is in a light-load operating condition, and the predetermined speed can be used to determine whether the engine speed is at or above a medium speed. In this case, when the load is greater than the predetermined load value, the alcohol ratio is close to a minimum value, and the speed is less than the predetermined speed, i.e., the alcohol content in the engine fuel is low, the engine is operating in a medium-to-high load range, and the engine is operating at a medium-to-low speed. In other words, the engine is in a medium-to-low speed, high-load range, where knock is strong and pre-ignition is likely to occur. Therefore, the injection mode can be determined to be the dual-injection mode, and the injection ratio can be determined to be the second injection ratio. This can address knock and pre-ignition issues and improve engine power output.

[0063] Optionally, when the load is greater than a predetermined load value, the alcohol ratio is close to a minimum value, and the speed is greater than a predetermined speed, the injection mode is determined to be the dual-injection mode, and the injection ratio is determined to be the fourth injection ratio. The fourth injection ratio is between the second and third injection ratios. In this case, the predetermined load value can be used to determine whether the engine load is in a light-load operating condition, and the predetermined speed can be used to determine whether the engine speed is at or above medium speed. In this case, when the load is greater than the predetermined load value, the alcohol ratio is close to a minimum value, and the speed is greater than the predetermined speed, i.e., the alcohol content in the engine fuel is low, the engine is operating in a medium-to-high load range, and the engine is operating at a medium-to-high speed, the injection mode can be determined to be the dual-injection mode, and the injection ratio can be determined to be the fourth injection ratio. The fourth injection ratio adds more port injection to the second injection ratio, thereby enabling the engine to achieve high power output while maintaining optimal direct injection duration and injection timing.

[0064] In some embodiments, the determined injection mode may be stored in an electronic control unit (ECU) of the engine.

[0065] In some embodiments, the injection mode control map can be optimized based on the calibration of the operating conditions and fuel composition characteristics, which can specifically include selecting a direct injection only injection mode, an intake port only injection mode, and a dual injection mode with different ratios.

[0066] In some embodiments, step S300 may further determine a target intake air volume, a target air-fuel ratio, and a target fuel injection volume for the engine. The target intake air volume is the amount of fresh air required to generate the target torque under the engine state and environmental conditions; the target air-fuel ratio is the air-to-fuel ratio required for combustion and enrichment protection; and the target fuel injection volume is the amount of direct injection and port injection required for combustion and enrichment protection.

[0067] In some embodiments, the target intake air amount, target air-fuel ratio, and target fuel injection amount can be calculated and calibrated based on the fuel-air combustion reaction formula, fuel component characteristics, and operating conditions.

[0068] In the embodiments of this application, in direct injection mode, the fuel injection pressure can be flexibly controlled based on fuel composition, operating conditions, and the direct injection ratio. When using a fuel with a low alcohol content, the fuel is less corrosive, and a higher fuel injection pressure is used to achieve better combustion and emissions performance. When using a fuel with a high alcohol content, the fuel injection pressure can be appropriately reduced to reduce corrosiveness. For port injection, a fixed lower pressure that satisfies the injection pressure is uniformly used.

[0069] Figure 2 It is a flowchart of the calibration process of step S300 in an embodiment of the present application.

[0070] In some embodiments, as described above, the present invention can calibrate the preferred injection mode control map based on the operating conditions and fuel composition characteristics. Figure 2 The calibration process of step S300 may specifically include:

[0071] Step S310 : If the alcohol ratio is close to the minimum value, 1:0 is used as the initial injection ratio, and the fuel injection amount in the port injection mode is increased by a first predetermined increment to obtain multiple injection ratios.

[0072] Here, 1 and 0 refer to percentages, 1 specifically refers to 100%, 0 specifically refers to 0% or not used, the first preset increment is also called "step size", and the first preset increment can be 0.1, 0.2, 0.3 or more.

[0073] When the alcohol ratio approaches its minimum value, meaning the engine's fuel has a low alcohol content, the octane rating of the fuel is low, resulting in poor knock resistance and a high tendency to pre-ignition. This affects the engine's low- and medium-speed power output, making it unsuitable to use a higher compression ratio to improve cycle thermal efficiency. Therefore, an initial injection ratio of 1:0 is used, meaning the engine primarily operates in direct injection mode. The fuel injection rate in port injection mode is increased by a first predetermined increment to achieve multiple injection ratios. For example, if the first predetermined increment is 0.2, the resulting injection ratios may include 1:0, 0.8:0.2, 0.6:0.4, and more. This process can be expressed as (1-x):x, where x is the port injection ratio.

[0074] In some embodiments, the fuel injection amount in the direct injection mode may be reduced by a first predetermined increment in step S310 to achieve multiple injection ratios. That is, in this embodiment of the present application, the fuel injection amount in the port injection mode may be inversely correlated with the fuel injection amount in the direct injection mode. For example, as the fuel injection amount in the port injection mode increases, the fuel injection amount in the direct injection mode decreases.

[0075] In some embodiments, the obtained injection ratios may be used as the second injection ratio and the fourth injection ratio according to the overall performance of the engine.

[0076] See also Figure 2 The calibration process of step S300 may further include:

[0077] Step S320: If the alcohol ratio is close to the maximum value, 0:1 is used as the initial injection ratio, and the fuel injection amount in the direct injection mode is increased by a second preset increment to obtain multiple injection ratios.

[0078] Among them, 1 and 0 refer to percentages, 1 specifically refers to 100%, and 0 specifically refers to 0% or not used. The second preset increment can be the same as the first preset increment, that is, the second preset increment can be 0.1, 0.2, 0.3 or more.

[0079] When the alcohol ratio approaches its maximum value, meaning the engine's fuel contains a high alcohol content, the engine's knock resistance is high and pre-ignition tendency is low, enabling high power at low and medium speeds and good combustion phasing. However, this leads to issues such as low fuel calorific value, large injection volume, and long injection duration, which can lead to wall wetting, oil dilution, deteriorating combustion and emissions, and poor fuel volatility at low temperatures, making cold starts difficult. Furthermore, high alcohol content is highly corrosive, a problem that becomes more pronounced when the engine operates at high rail pressure. Therefore, an initial injection ratio of 0:1 is used, meaning the engine primarily operates in port injection mode. The direct injection fuel injection rate is then increased in second, predetermined increments to achieve multiple injection ratios. For example, if the second predetermined increment is 0.2, the resulting injection ratios may include 0:1, 0.2:0.8, 0.4:0.6, and more. This process can be expressed as x:(1-x), where x is the port injection ratio.

[0080] In some embodiments, the fuel injection amount in the port injection mode may be reduced by a second predetermined increment in step S320 to obtain multiple injection ratios. That is, in this embodiment of the present application, the fuel injection amount in the port injection mode may be inversely correlated with the fuel injection amount in the direct injection mode. For example, as the fuel injection amount in the port injection mode increases, the fuel injection amount in the direct injection mode decreases.

[0081] In some embodiments, the obtained injection ratio may be used as the first injection ratio according to the comprehensive performance of the engine.

[0082] In addition, in the embodiment of the present application, the order of step S310 and step S320 may not be limited, that is, step S310 may also be executed after step S320.

[0083] See also Figure 2 The calibration process of step S300 may further include:

[0084] Step S330: Calibrate the operating conditions and multiple injection ratios.

[0085] The calibration is related to the engine speed, injection timing and allowable rail pressure.

[0086] Figure 3 This is a flow chart of the calibration process of another embodiment of step S300 of the embodiment of the present application. Figure 2 and Figure 3 The difference between the embodiment of FIG. 1 and FIG. 2 is that step S300 may further include:

[0087] Step S321: Calculate the median of the alcohol ratio, use the predicted value of the direct injection ratio under the median as the initial injection ratio, and increase or decrease the fuel injection amount in the direct injection mode by a third preset increment to obtain multiple injection ratios.

[0088] In practice, when the alcohol ratio issue is less pronounced, the alcohol ratio can be assumed to be between the maximum and minimum values. In this case, the median alcohol ratio needs to be calculated and predicted. The median alcohol ratio is equal to the sum of the maximum and minimum alcohol ratios divided by 2. The predicted direct injection ratio value can be between 0 and 0.5 or between 0.5 and 1. If the predicted direct injection ratio value is between 0 and 0.5, the fuel injection amount in direct injection mode is increased by a third preset increment. If the predicted direct injection ratio value is between 0.5 and 1, the fuel injection amount in direct injection mode is decreased by a third preset increment. The third preset increment can be the same as the first preset increment.

[0089] In some embodiments, the fuel injection amount in the port injection mode may be increased or decreased by a third predetermined increment in step S330 to obtain multiple injection ratios. That is, in this embodiment of the present application, the fuel injection amount in the port injection mode may be inversely correlated with the fuel injection amount in the direct injection mode. For example, as the fuel injection amount in the port injection mode increases, the fuel injection amount in the direct injection mode decreases.

[0090] In some embodiments, the obtained injection ratio may be used as the third injection ratio according to the comprehensive performance of the engine.

[0091] Figure 4 This is a flow chart of the calibration process of another embodiment of step S300 of the present application. Figure 2 、 Figure 3 and Figure 4 The difference between the embodiment of FIG. 1 and FIG. 2 is that step S300 may further include:

[0092] Step S340: obtaining an initial calibration curve based on the maximum value, the median value, and the minimum value.

[0093] Step S341: increasing or decreasing the content of the flexible alcohol by a fourth preset increment to obtain a plurality of alcohol ratios.

[0094] Step S342: interpolating and optimizing the multiple alcohol ratios with the initial calibration curve to obtain a final calibration curve.

[0095] The fourth preset increment may be determined according to comprehensive performance of the engine.

[0096] Therefore, a calibration curve can be generated through steps S340 to S342 to improve the above calibration accuracy.

[0097] See also Figure 1 The control method involved in the embodiment of the present application may further include:

[0098] Step S400: Controlling the engine operation based on the fuel injection mode and injection ratio.

[0099] Figure 5 This is a sub-flowchart of step S400 of the embodiment of the present application. In other embodiments, please refer to Figure 5 , step S400 may include:

[0100] Step S401: Control at least one of the fuel injection pressure, fuel injection amount, fuel injection timing, intake and exhaust, or ignition combustion of the engine based on the fuel injection mode and injection ratio.

[0101] Step S402: Obtain the model output torque and target output torque of the engine.

[0102] The model output torque is defined as the actual output torque of the engine based on the fuel injection mode and injection ratio, and the target output torque is defined as the theoretical output torque of the engine based on the fuel injection mode and injection ratio.

[0103] Step S403: If the model output torque is less than the target output torque, at least one of the injection pressure, injection amount, injection timing, intake and exhaust, or ignition combustion of the engine is re-controlled based on the fuel injection mode and injection ratio.

[0104] In this way, the engine can be closed-loop controlled to improve the control accuracy.

[0105] Figure 6 This is a flowchart of another embodiment of the engine control method of the embodiment of the present application.

[0106] See also Figure 6 In some embodiments, the control method may further include:

[0107] Step S500: Obtain the oxygen content of the engine, and obtain the air-fuel ratio of the engine based on the oxygen content.

[0108] After executing step S500 , the alcohol ratio in the engine may be re-acquired based on the air-fuel ratio, that is, step S200 may be re-executed.

[0109] This allows closed-loop confirmation of the alcohol ratio in the engine, improving control accuracy.

[0110] Furthermore, the control method of this application adds a dual-injection mode compared to a single-injection mode. This eliminates the need to significantly increase the injector's flow rate range compared to existing mature models while also accommodating low-flow demand conditions, reducing injector development costs. Furthermore, in the control method of the embodiments of this application, appropriately reducing rail pressure can reduce development costs for corrosion protection optimization. Furthermore, the control method of the embodiments of this application can eliminate the need for additional mechanisms for startup optimization in the single-injection mode.

[0111] Figure 7 It is a structural block diagram of the engine of an embodiment of the present application.

[0112] See also Figure 7 An embodiment of the present application further provides an engine 1, which may be an alcohol fuel engine, and may include a control device 11, an engine body 12, an intake system 13, a fuel supply system 14, and an exhaust after-treatment system 15; the control device 11 is connected to the engine body 12, the intake system 13, the fuel supply system 14, and the exhaust after-treatment system 15, and the control device 11 is used to execute the control method of any of the above embodiments of the present application to control the engine 1; the fuel supply system 14 includes a first sensor for detecting the alcohol content; the exhaust after-treatment system 15 includes a second sensor for detecting the oxygen content.

[0113] In some embodiments, the intake system 13 may include an air filter, a supercharger, an intake intercooler, an intake manifold, and a plurality of intake manifolds.

[0114] In some embodiments, the fuel supply system 14 may include a direct injection subsystem 141 and a port injection subsystem 142. The direct injection subsystem 141 may include a high-pressure fuel injector, a high-pressure fuel rail, a high-pressure fuel pump, and connecting piping, while the port injection subsystem 142 may include a low-pressure fuel injector, a low-pressure fuel rail, a low-pressure fuel pump, and connecting piping. In other embodiments, the port injection subsystem 142 may also include a pressure reducing device. In other embodiments, the low-pressure fuel pump may not be provided, and the fuel of the port injection subsystem 142 may be supplied by the high-pressure fuel pump of the direct injection subsystem 141 and then output as low-pressure fuel through the pressure reducing device.

[0115] In an embodiment of the present application, the fuel supply system 14 can use flexible alcohol fuels with different alcohol contents, and provide sufficient fresh air through the intake system 13 to be fully mixed with the fuel in the cylinder or in the intake manifold of each cylinder. The fuel directly injected into the cylinder is directly injected into the cylinder, and the mixture formed by the intake port injection in the intake manifold enters the cylinder and is further fully mixed or further fully mixed with the fuel directly injected into the cylinder. After the mixture is ignited and burned in the combustion chamber, it enters the exhaust system after passing through the exhaust pipe and the supercharger turbine to do work.

[0116] In some embodiments, the exhaust aftertreatment system 15 may further include an exhaust pipe, and the second sensor may be disposed in the exhaust pipe.

[0117] In the direct injection subsystem 141, the fuel passes through the high-pressure oil pump and enters the high-pressure oil rail. It is directly injected into the cylinder from the high-pressure injector arranged on the top of the engine body 12 or on the intake side, and is mixed with the fresh air entering through the intake manifold or the oil-gas mixture injected into the intake duct to form an oil-gas mixture. The mixture is ignited and burned in the engine combustion chamber. The burned mixture enters the exhaust after-treatment system 15 after performing work through the supercharger and is finally discharged into the atmosphere.

[0118] In the intake port injection subsystem 142, the fuel passes through a low-pressure oil pump or a high-pressure oil pump first and then a pressure reducing device, and enters a low-pressure oil pipe arranged on the intake manifold. The fuel is sprayed into the intake manifold of each cylinder by a low-pressure injector, and mixed with the fresh air that has been supercharged by the supercharger and cooled by the intercooler in the intake manifold to form an oil-gas mixture. When the intake valve is opened, the fuel enters the cylinder, and participates in the next step of mixing or direct ignition and combustion in the engine combustion chamber. The burned mixture enters the exhaust after-treatment system 15 after the supercharger performs work, and is finally discharged into the atmosphere.

[0119] In some embodiments, the control device 11 may be a vehicle ECU. The ECU can control the fuel pressure, injection quantity, or injection timing of the direct injection subsystem 141 and the port injection subsystem 142. It also performs operating and closed-loop control of the dual-injection system based on signals from an alcohol content sensor in the fuel supply system 14, signals from an oxygen sensor in the exhaust aftertreatment system 15, and operating conditions. Optimal engine control is achieved by matching dual-injection mode parameters with other parameters.

[0120] An embodiment of the present application further provides an electronic device, which includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the engine control method of any of the above embodiments of the present application is implemented.

[0121] An embodiment of the present application further provides a computer-readable storage medium, which stores a computer program, and is characterized in that when the computer program is executed by a processor, the engine control method of any of the above embodiments of the present application is implemented.

[0122] An embodiment of the present application also provides a vehicle, the vehicle includes an engine, the engine includes a control device, and the control device is used to execute the engine control method of any of the above embodiments of the present application.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A method for controlling an engine, characterized in that: include: Get the engine's operating conditions; obtaining a proportion of alcohol in the engine; determining a fuel injection mode and an injection ratio based on the operating conditions and the alcohol ratio; controlling the engine operation based on the fuel injection mode and the injection ratio; The operating conditions include at least the load, temperature, and start / stop state of the engine; the alcohol ratio is defined as the ratio of the content of the flexible alcohol to the content of the fuel; the injection modes include direct injection, port injection, and dual injection; and the injection ratio is defined as the ratio of the fuel injection amount in the direct injection mode to the fuel injection amount in the port injection mode. The determining of the fuel injection mode and injection ratio based on the operating conditions and the alcohol ratio includes: When the load is less than a predetermined load value, the temperature is less than a preset temperature value, or the start-stop state is start, determining that the injection mode is the cylinder direct injection mode; When the load is greater than the predetermined load value and the alcohol ratio is close to a maximum value, determining the injection mode to be the dual injection mode and determining the injection ratio to be a first injection ratio, wherein the first injection ratio is defined as a ratio when the fuel injection amount in the direct injection mode is less than the fuel injection amount in the port injection mode; When the load is greater than the predetermined load value and the alcohol ratio is close to a minimum value, determining the injection mode to be the dual injection mode and determining the injection ratio to be a second injection ratio, wherein the second injection ratio is defined as a ratio when the fuel injection amount in the direct injection mode is greater than the fuel injection amount in the port injection mode; When the load is greater than the predetermined load value and the alcohol ratio is between the minimum value and the maximum value, the injection mode is determined to be the dual injection mode, and the injection ratio is determined to be a third injection ratio, wherein the third injection ratio is between the first injection ratio and the second injection ratio.

2. The engine control method according to claim 1, characterized in that: The operating conditions also include the speed of the engine; The determining of the fuel injection mode and injection ratio based on the operating conditions and the alcohol ratio includes: When the load is greater than the predetermined load value, the alcohol ratio is close to the minimum value, and the speed is less than a predetermined speed, determining the injection mode to be the dual injection mode, and determining the injection ratio to be the second injection ratio; When the load is greater than the predetermined load value, the alcohol ratio is close to the minimum value, and the speed is greater than the predetermined speed, determining the injection mode to be the dual injection mode and determining the injection ratio to be a fourth injection ratio; The fourth injection ratio is between the second injection ratio and the third injection ratio.

3. The engine control method according to claim 1, characterized in that: Determining the injection ratio includes: If the alcohol ratio is close to a minimum value, using 1:0 as an initial injection ratio and increasing the fuel injection amount in the port injection mode by a first predetermined increment to obtain a plurality of injection ratios; If the alcohol ratio is close to a maximum value, using 0:1 as an initial injection ratio and increasing the fuel injection amount in the direct injection mode by a second predetermined increment to obtain multiple injection ratios; The operating condition is calibrated with the plurality of injection ratios, wherein the calibration is related to a speed of the engine, a fuel injection time, and an allowable rail pressure.

4. The engine control method according to claim 3, characterized in that: Determining the injection ratio further includes: calculating a median value of the alcohol ratio, using a predicted direct injection ratio at the median value as an initial injection ratio, and increasing or decreasing the fuel injection amount in the direct injection mode by a third predetermined increment to obtain a plurality of injection ratios, wherein the median value is equal to the sum of the maximum value and the minimum value divided by 2; The operating conditions are calibrated with the plurality of injection ratios.

5. The engine control method according to claim 4, characterized in that: Determining the injection ratio further includes: obtaining an initial calibration curve based on the maximum value, the median value, and the minimum value; increasing or decreasing the content of the flexible alcohol by a fourth predetermined increment to obtain a plurality of alcohol ratios; The multiple alcohol ratios are interpolated and optimized with the initial calibration curve to obtain a final calibration curve.

6. The engine control method according to claim 1, characterized in that: The control method further includes: acquiring an oxygen content of the engine, and obtaining an air-fuel ratio of the engine based on the oxygen content; The alcohol ratio in the engine is retrieved based on the air-fuel ratio.

7. The engine control method according to claim 1, characterized in that: The controlling the engine operation based on the fuel injection mode and the injection ratio includes: At least one of injection pressure, injection amount, injection timing, intake and exhaust, or ignition combustion of the engine is controlled based on the fuel injection mode and the injection ratio.

8. The engine control method according to claim 7, characterized in that: The controlling the engine operation based on the fuel injection mode and the injection ratio further includes: obtaining a model output torque and a target output torque of the engine, wherein the model output torque is defined as an actual output torque of the engine based on the fuel injection mode and the injection ratio, and the target output torque is defined as a theoretical output torque of the engine based on the fuel injection mode and the injection ratio; If the model output torque is less than the target output torque, at least one of the injection pressure, injection amount, injection timing, intake and exhaust, or ignition combustion of the engine is re-controlled based on the fuel injection mode and the injection ratio.

9. An engine, characterized in that: The invention comprises a control device, an engine body, an air intake system, a fuel supply system and an exhaust after-treatment system; the control device is connected to the engine body, the air intake system, the fuel supply system and the exhaust after-treatment system, and is used to execute the control method described in any one of claims 1 to 7 to control the engine; the fuel supply system includes a first sensor for detecting the alcohol content; the exhaust after-treatment system includes a second sensor for detecting the oxygen content.

10. An electronic device, characterized in that: The electronic device includes a memory and a processor, the memory stores a computer program, and the processor implements the engine control method according to any one of claims 1 to 7 when executing the computer program.

11. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the engine control method according to any one of claims 1 to 7 is implemented.

12. A vehicle, characterized in that: The vehicle includes an engine, and the engine includes a control device. The control device is configured to execute the engine control method according to any one of claims 1 to 7.

Images