Cold starting method of engine and vehicle

Abstract

The invention provides a cold starting method of an engine and a vehicle, the method is applied to the field of vehicles, the engine comprises a direct injection nozzle and an air channel injection nozzle, and the method comprises the steps that the current temperature of cooling liquid in the engine of the vehicle is obtained; under the condition that the current temperature is smaller than or equal to a preset temperature threshold value, the current rotating speed of the engine is obtained, and based on the current temperature of the cooling liquid and the current rotating speed of the engine, the first target fuel injection quantity proportion between fuel injection quantities of a direct injection nozzle and an air channel injection nozzle of the engine during fuel injection is determined; and controlling the direct injection nozzle and the air passage injection nozzle to perform fuel injection according to the first target fuel injection quantity proportion so as to control the cold start of the engine. The method can help the engine complete cold starting as soon as possible, and the success rate of cold starting of the engine is increased.

Description

Technical Field

[0001] The present application relates to the field of vehicles, and more particularly, to a cold start method of an engine and a vehicle in the field of vehicles. Background Art

[0002] At present, with the continuous development of the automobile industry, engine starting has gradually become a hot topic of concern. When a vehicle is cold started at extremely low temperatures, considering fuel economy, it is usually cold started by directly injecting fuel into the engine cylinder through the Gasoline Direct Injection (GDI) system. If the GDI single injection starting effect is poor, the GDI multiple injection method is usually used to optimize the cold start.

[0003] When the battery is fully charged and the engine oil is in good condition, the reliability of cold starting at extremely low temperatures is high. However, compared with a good battery condition, the drag speed during cold starting will be worse when the battery is slightly low, resulting in poor reliability of cold starting and possible starting failure. Summary of the invention

[0004] The present application provides an engine cold start method and a vehicle, which can help the engine complete the cold start as quickly as possible and improve the success rate of the engine cold start.

[0005] In a first aspect, a method for cold starting an engine is provided, wherein the engine includes a direct injection nozzle and an airway injection nozzle, the method comprising: obtaining a current temperature of a coolant in an engine of a vehicle; when the current temperature is less than or equal to a preset temperature threshold, obtaining a current speed of the engine, and determining a first target fuel injection amount ratio between the fuel injection amounts of the direct injection nozzle and the airway injection nozzle of the engine when performing fuel injection based on the current temperature of the coolant and the current speed of the engine; and controlling the direct injection nozzle and the airway injection nozzle to perform fuel injection according to the first target fuel injection amount ratio to control the cold start of the engine.

[0006] The above technical solution can determine whether the current engine belongs to the cold start scenario by obtaining the current temperature of the coolant in the engine. When it is determined that the engine belongs to the cold start scenario, the current speed of the engine can be obtained, and based on the current speed of the engine and the current temperature of the coolant, the target fuel injection ratio between the direct injection nozzle and the airway injection nozzle of the engine is determined, and then the direct injection nozzle and the airway injection nozzle are controlled to perform fuel injection according to the target fuel injection ratio, which can help the engine complete the cold start as soon as possible. Because the viscosity of the fuel in the engine increases under low temperature conditions, it is not conducive to atomization. When it is determined that the current temperature is less than or equal to the preset temperature threshold, a dual injection strategy of co-injection of the direct injection nozzle and the airway injection nozzle is adopted, which can control the airway injection nozzle in the intake manifold injection system to spray fuel into the intake manifold, and use the help of the intake airflow to better disperse the fuel, form a more uniform mixture, improve combustion efficiency, and thus achieve engine start faster. And it can reduce the demand for high-pressure injection when the direct injection nozzle is used alone to inject fuel, thereby avoiding starting failure caused by insufficient oil pumping of the high-pressure oil pump, and can improve the success rate of starting.

[0007] In combination with the first aspect, in certain implementations of the first aspect, based on the current temperature of the coolant and the current speed of the engine, a first target fuel injection amount ratio between the fuel injection amounts of the direct injection nozzle and the airway injection nozzle of the engine when performing fuel injection is determined, including: based on a first preset corresponding relationship, determining the first target fuel injection amount ratio corresponding to the current temperature and the current speed; wherein the first preset corresponding relationship is a corresponding relationship between a target parameter and a target fuel injection amount ratio; the target parameters include the temperature of the coolant and the speed of the engine; the target fuel injection amount ratio is the fuel injection amount ratio between the direct injection nozzle and the airway injection nozzle when performing fuel injection.

[0008] The above technical solution determines the first target fuel injection ratio based on the current temperature of the coolant and the current speed of the engine, which can make the fuel injection amount of the direct injection nozzle and the airway injection nozzle more in line with the actual operation requirements of the engine, and can make the mixed gas reach a more ideal state under different working conditions, thereby improving the utilization rate of fuel and reducing fuel consumption. By reasonably adjusting the fuel injection ratio between the direct injection nozzle and the airway injection nozzle, it can also ensure that the engine obtains appropriate fuel supply under various working conditions, thereby improving the success rate of cold starting of the engine.

[0009] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, controlling the direct injection nozzle and the airway injection nozzle to perform fuel injection according to the first target injection amount ratio, including: determining the total injection amount required for the engine cold start; based on the total injection amount and the first target injection amount ratio, determining the first injection amount corresponding to the direct injection nozzle, and determining the second injection amount corresponding to the airway injection nozzle; wherein the sum of the first injection amount and the second injection amount is the total injection amount; controlling the direct injection nozzle to perform fuel injection according to the first injection amount, and controlling the airway injection nozzle to perform fuel injection according to the second injection amount.

[0010] In combination with the first aspect and the above-mentioned implementation methods, in some implementation methods of the first aspect, controlling the direct injection nozzle to perform fuel injection according to the first injection amount includes: when it is determined that the direct injection nozzle performs fuel injection multiple times, based on a second preset correspondence, determining a second target injection amount ratio corresponding to the current temperature of the coolant; wherein the second preset correspondence is a correspondence between the temperature of the coolant and the injection amount ratio of each injection during multiple fuel injections; the second target injection amount ratio is a ratio between the injection amounts of each injection during multiple fuel injections by the direct injection nozzle; based on the first injection amount and the second target injection amount ratio, determining a single injection amount each time the direct injection nozzle performs fuel injection; and controlling the direct injection nozzle to perform fuel injection according to the single injection amount each time fuel injection is performed.

[0011] In combination with the first aspect and the above-mentioned implementation methods, in some implementation methods of the first aspect, controlling the direct injection nozzle to inject fuel according to the first injection amount, and controlling the airway injection nozzle to inject fuel according to the second injection amount, includes: determining a first injection time when the direct injection nozzle performs fuel injection, and determining a second injection time when the airway injection nozzle performs fuel injection; controlling the direct injection nozzle to inject fuel according to the first injection amount at the first injection time, and controlling the airway injection nozzle to inject fuel according to the second injection amount at the second injection time.

[0012] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, determining the first injection time when the direct injection nozzle performs fuel injection includes: obtaining the current operating parameters of the engine; wherein the current operating parameters include the current speed and the current load; based on a third preset correspondence, determining the target starting time for the direct injection nozzle to perform fuel injection corresponding to the current operating parameters; wherein the third preset corresponding relationship is the correspondence between the operating parameters and the starting time for the direct injection nozzle to perform fuel injection; the operating parameters include the speed and the load; based on a fourth preset correspondence, determining the target ending time for the direct injection nozzle to perform fuel injection corresponding to the current operating parameters; wherein the fourth preset corresponding relationship is the correspondence between the operating parameters and the ending time for the direct injection nozzle to perform fuel injection; when it is determined that the number of injections when the direct injection nozzle performs fuel injection is multiple times, based on the target starting time and the target ending time, determine the first injection time each time the direct injection nozzle performs fuel injection.

[0013] The above technical solution determines the target start time and target end time of the direct injection nozzle for fuel injection based on the current engine speed and current load, so that the fuel can be injected into the cylinder at the best time. When the number of injections of the direct injection nozzle is determined to be multiple times, the first injection time of each time is determined based on the target start time and target end time, which can achieve more precise fuel injection control. In addition, the injection time of the above direct injection nozzle is dynamically adjusted according to the actual working conditions to ensure that the engine can perform at its best under various working conditions and improve the reliability of the engine.

[0014] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, determining the second injection timing when the airway injection nozzle performs fuel injection includes: obtaining the opening timing of the intake valve of the engine, and obtaining the injection delay angle when the airway injection nozzle performs fuel injection; wherein the injection delay angle is the crankshaft angle between the start timing of the fuel injection of the airway injection nozzle and the opening timing of the intake valve; based on the opening timing of the intake valve and the injection delay angle, determining the second injection timing when the airway injection nozzle performs fuel injection.

[0015] The above technical solution determines the second injection timing of the airway injection nozzle for fuel injection based on the intake valve opening timing and the injection delay angle, so that the fuel can be injected into the intake duct at the most appropriate time and fully mixed with the intake air flow to form a uniform mixture, thereby ensuring that the mixture reaches the optimal state when entering the cylinder, improving combustion efficiency, and thereby improving the success rate of engine cold start.

[0016] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, obtaining the injection delay angle of the airway injection nozzle when performing fuel injection includes: obtaining the current temperature of the coolant, the intake temperature of the air entering the intake manifold of the engine and the current speed of the engine; determining the injection delay angle based on the current temperature of the coolant, the intake temperature and the current speed of the engine.

[0017] In combination with the first aspect and the above-mentioned implementation methods, in certain implementation methods of the first aspect, the direct injection nozzle and the airway injection nozzle are controlled to perform fuel injection according to the first target fuel injection amount ratio to control the cold start of the engine, including: based on the current temperature of the coolant, determining the target oil pressure corresponding to the current temperature; controlling the fuel pump of the engine to adjust the fuel pressure inside the engine; when it is determined that the fuel pressure inside the engine reaches the target oil pressure, controlling the direct injection nozzle and the airway injection nozzle to perform fuel injection according to the first target fuel injection amount ratio to control the cold start of the engine.

[0018] The above technical solution determines the target oil pressure based on the current temperature and controls the fuel pump to adjust the fuel pressure, which can make the fuel have a higher pressure when injected, thereby improving the atomization effect of the fuel. Better atomization can make the fuel and air mix more fully, improve the stability and reliability of combustion, and help the engine reach a stable operating state faster during cold start. By accurately controlling the fuel pressure to reach the target oil pressure, the direct injection nozzle and the airway injection nozzle can perform fuel injection according to the first target injection amount ratio, ensuring that the mixture concentration is within an appropriate range, and improving the success rate of engine cold start.

[0019] In a second aspect, a cold start device for an engine is provided, which includes a direct injection nozzle and an airway injection nozzle, and the device includes: an acquisition module for acquiring a current temperature of a coolant in an engine of a vehicle; a determination module for acquiring a current speed of the engine when the current temperature is less than or equal to a preset temperature threshold, and determining a first target fuel injection amount ratio between the fuel injection amounts of the direct injection nozzle and the airway injection nozzle of the engine when performing fuel injection based on the current temperature of the coolant and the current speed of the engine; and a control module for controlling the direct injection nozzle and the airway injection nozzle to perform fuel injection according to the first target fuel injection amount ratio, so as to control the cold start of the engine.

[0020] In combination with the second aspect, in certain implementations of the second aspect, the determination module is specifically used to: determine a first target fuel injection amount ratio corresponding to the current temperature and the current speed based on a first preset corresponding relationship; wherein the first preset corresponding relationship is a corresponding relationship between a target parameter and a target fuel injection amount ratio; the target parameter includes the temperature of the coolant and the speed of the engine; the target fuel injection amount ratio is the fuel injection amount ratio when the direct injection nozzle and the airway injection nozzle perform fuel injection.

[0021] In combination with the second aspect and the above-mentioned implementation methods, in certain implementation methods of the second aspect, the control module is specifically used to: determine the total amount of fuel injection required for the cold start of the engine; based on the ratio of the total amount of fuel injection and the first target fuel injection amount, determine the first fuel injection amount corresponding to the direct injection nozzle, and determine the second fuel injection amount corresponding to the airway injection nozzle; wherein the sum of the first fuel injection amount and the second fuel injection amount is the total amount of fuel injection; control the direct injection nozzle to inject fuel according to the first fuel injection amount, and control the airway injection nozzle to inject fuel according to the second fuel injection amount.

[0022] In combination with the second aspect and the above-mentioned implementation methods, in some implementation methods of the second aspect, the control module includes a direct injection nozzle control unit, which is specifically used to: when it is determined that the direct injection nozzle performs multiple fuel injections, determine a second target injection amount ratio corresponding to the current temperature of the coolant based on a second preset correspondence; wherein the second preset correspondence is a correspondence between the temperature of the coolant and the injection amount ratio of each injection during multiple fuel injections; the second target injection amount ratio is a ratio between the injection amounts of each injection when the direct injection nozzle performs multiple fuel injections; based on the first injection amount and the second target injection amount ratio, determine a single injection amount when the direct injection nozzle performs fuel injection each time; and control the direct injection nozzle to inject fuel according to the single injection amount each time fuel injection is performed.

[0023] In combination with the second aspect and the above-mentioned implementation methods, in some implementation methods of the second aspect, the control module includes a control unit, which is specifically used to: determine a first injection time when the direct injection nozzle performs fuel injection, and determine a second injection time when the airway injection nozzle performs fuel injection; control the direct injection nozzle to inject fuel according to the first injection amount at the first injection time, and control the airway injection nozzle to inject fuel according to the second injection amount at the second injection time.

[0024] In combination with the second aspect and the above-mentioned implementation methods, in some implementation methods of the second aspect, the control unit includes a first determination unit, which is specifically used to: obtain current operating parameters of the engine; wherein the current operating parameters include current speed and current load; based on a third preset correspondence, determine the target start time of fuel injection by the direct injection nozzle corresponding to the current operating parameters; wherein the third preset correspondence is the correspondence between the operating parameters and the start time of fuel injection by the direct injection nozzle; the operating parameters include speed and load; based on a fourth preset correspondence, determine the target end time of fuel injection by the direct injection nozzle corresponding to the current operating parameters; wherein the fourth preset correspondence is the correspondence between the operating parameters and the end time of fuel injection by the direct injection nozzle; when it is determined that the number of injections when the direct injection nozzle performs fuel injection is multiple times, based on the target start time and the target end time, determine the first injection time of each fuel injection by the direct injection nozzle.

[0025] In combination with the second aspect and the above-mentioned implementation methods, in some implementation methods of the second aspect, the control unit includes a second determination unit, which is specifically used to: obtain the opening time of the intake valve of the engine, and obtain the injection delay angle when the airway injection nozzle performs fuel injection; wherein the injection delay angle is the crankshaft angle between the start time of the fuel injection of the airway injection nozzle and the opening time of the intake valve; based on the opening time of the intake valve and the injection delay angle, determine the second injection time when the airway injection nozzle performs fuel injection.

[0026] In combination with the second aspect and the above-mentioned implementation methods, in some implementation methods of the second aspect, the second determination unit includes an acquisition unit, which is specifically used to: obtain the current temperature of the coolant, the intake temperature of the air entering the intake manifold of the engine and the current speed of the engine; determine the injection delay angle based on the current temperature of the coolant, the intake temperature and the current speed of the engine.

[0027] In combination with the second aspect and the above-mentioned implementation methods, in certain implementation methods of the second aspect, the control module is specifically used to: determine the target oil pressure corresponding to the current temperature based on the current temperature of the coolant; control the fuel pump of the engine to adjust the fuel pressure inside the engine; and when it is determined that the fuel pressure inside the engine reaches the target oil pressure, control the direct injection nozzle and the airway injection nozzle to inject fuel according to the first target fuel injection amount ratio to control the cold start of the engine.

[0028] In a third aspect, a vehicle is provided, comprising a memory and a processor. The memory is used to store executable program code, and the processor is used to call and run the executable program code from the memory, so that the vehicle executes the cold start method of the engine in the first aspect and any possible implementation of the first aspect.

[0029] In a fourth aspect, a computer program product is provided, the computer program product comprising: a computer program code, when the computer program code is run on a computer, the computer executes the engine cold start method in the above-mentioned first aspect and any possible implementation of the first aspect.

[0030] In a fifth aspect, a computer-readable storage medium is provided, which stores a computer program code. When the computer program code runs on a computer, the computer executes the engine cold start method in the above-mentioned first aspect and any possible implementation of the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a schematic flow chart of a cold start method of an engine provided in an embodiment of the present application;

[0032] Figure 2 is a schematic flow chart of an engine starting method provided in an embodiment of the present application;

[0033] Figure 3 It is a structural schematic diagram of a cold start device for an engine provided in an embodiment of the present application;

[0034] Figure 4 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application. DETAILED DESCRIPTION

[0035] The technical solution in the present application will be described clearly and in detail below in conjunction with the accompanying drawings. In the description of the embodiments of the present application, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present application, "multiple" means two or more than two.

[0036] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as suggesting or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0037] At present, with the continuous development of the automobile industry, engine starting has gradually become a hot issue of concern. When a vehicle is cold started at extremely low temperatures, considering fuel economy, it is usually cold started by GDI injection. If the GDI single injection starting effect is poor, GDI multiple injection is usually used to optimize the cold start.

[0038] Under the condition that the battery is fully charged and the engine oil is in good condition, the reliability of cold starting at extremely low temperatures is high. However, if the power of the vehicle's 12V battery is not high enough, the starter may not provide enough power to start the engine.

[0039] If the engine coolant temperature is extremely low, such as below -30℃ or -35℃, the internal parts of the engine will become hard, the resistance will increase, and the starter will also drag the engine to reduce the speed. When the engine speed is low, the working efficiency of the high-pressure oil pump is also low, resulting in poor oil pumping capacity. After the high-pressure oil pump's oil pumping capacity deteriorates, in order to ensure the smooth ignition of the engine, the number of GDI injections may be increased, but if the amount of each injection exceeds the actual amount of oil pumped by the high-pressure oil pump, the oil pressure in the oil rail will gradually decrease. When the oil pressure in the oil rail drops to a certain level, the high-pressure injection mode cannot be maintained, causing the injection pump to work only in low-pressure injection mode. In the low-pressure injection mode, the fuel atomization effect in the engine is poor, resulting in poor mixture formation, which affects the ignition success rate and causes the engine cold start failure.

[0040] In summary, under extremely low temperature conditions, the engine cold start process will encounter problems such as low starter drag speed, limited oil pumping capacity of the high-pressure oil pump, and gradual decrease in oil pressure in the high-pressure oil rail, which will lead to engine cold start failure.

[0041] In order to solve the above technical problems, an embodiment of the present application provides a cold start method for an engine, wherein the executor of the method is a vehicle, specifically a controller in the vehicle.

[0042] The engine cold start method provided in the embodiment of the present application is applied to a vehicle equipped with a dual injection system, wherein the engine of the vehicle is a dual injection system engine, and the dual injection system engine includes a GDI system and an intake manifold injection (Port Fuel Injection, PFI) system.

[0043] Among them, the GDI system uses a direct injection nozzle to directly spray fuel into the engine cylinder, where it is mixed with air and burned. The direct injection nozzle in the GDI system is usually installed on the cylinder head of the engine, close to the combustion chamber.

[0044] The PFI system uses a port injection nozzle to inject fuel in front of the intake valve in the intake manifold, rather than directly into the cylinder. The port injection nozzle in the PFI system is usually installed in the intake manifold of the engine, usually in front of the intake valve.

[0045] The above dual injection system can ensure that the engine can obtain the best fuel supply under various working conditions and improve the overall performance of the vehicle.

[0046] Figure 1 It is a schematic flow chart of a cold start method of an engine provided in an embodiment of the present application.

[0047] For example, Figure 1 As shown, the method 100 includes:

[0048] S101, obtaining the current temperature of the coolant in the engine of the vehicle.

[0049] S102, when the current temperature is less than or equal to a preset temperature threshold, obtain the current speed of the engine, and based on the current temperature of the coolant and the current speed of the engine, determine a first target injection amount ratio between the injection amounts of the engine's direct injection nozzle and the airway injection nozzle when performing fuel injection.

[0050] S103, controlling the direct injection nozzle and the port injection nozzle to perform fuel injection according to a first target fuel injection amount ratio to control the engine cold start.

[0051] In the embodiment of the present application, by obtaining the current temperature of the coolant in the engine, it can be determined whether the current engine belongs to the cold start scenario. When it is determined that the engine belongs to the cold start scenario, the current speed of the engine can be obtained, and based on the current speed of the engine and the current temperature of the coolant, the target fuel injection amount ratio between the direct injection nozzle and the airway injection nozzle of the engine is determined, and then the direct injection nozzle and the airway injection nozzle are controlled to perform fuel injection according to the target fuel injection amount ratio, which can help the engine complete the cold start as soon as possible. Because the viscosity of the fuel in the engine increases under low temperature conditions, it is not conducive to atomization. When it is determined that the current temperature is less than or equal to the preset temperature threshold, a dual injection strategy of co-injection of the direct injection nozzle and the airway injection nozzle is adopted, which can control the airway injection nozzle in the intake manifold injection system to spray fuel into the intake manifold, and use the help of the intake airflow to better disperse the fuel, form a more uniform mixture, improve combustion efficiency, and thus achieve engine start faster. And it can reduce the demand for high-pressure fuel injection when the direct injection nozzle is used alone to inject fuel, thereby avoiding starting failure caused by insufficient oil pumping of the high-pressure oil pump, and can improve the success rate of starting.

[0052] Below Figure 1 The specific implementation of each step in the embodiment shown is described as follows:

[0053] Regarding the above S101, it can be understood that the current temperature of the coolant in the above engine can also be referred to as the starting water temperature of the engine.

[0054] The current temperature of the coolant in the above engine is usually measured by a coolant temperature sensor. The coolant temperature sensor is a thermistor whose resistance value changes with the change of temperature. The coolant temperature sensor can convert the temperature signal into an electrical signal and send it to the engine controller.

[0055] For example, the coolant temperature sensor is usually installed in the engine water jacket or at the outlet of the engine radiator, directly in contact with the coolant. The coolant temperature sensor is a thermistor. When the temperature of the coolant increases, the resistance value decreases; when the temperature of the coolant decreases, the resistance value increases. The coolant temperature sensor converts the resistance change into a voltage signal and sends the voltage signal to the engine controller. The engine controller determines the current temperature of the coolant based on the received voltage signal.

[0056] During engine operation, coolant circulates through the engine, absorbing heat and transferring it to the radiator to maintain the engine's operating temperature within a suitable range. The coolant temperature usually directly affects the engine's performance and efficiency. For example, if the current coolant temperature is too low, more fuel is required to start the engine; if the current coolant temperature is too high, the engine may overheat, resulting in reduced engine performance or even overheating damage.

[0057] Furthermore, after the current temperature of the coolant in the engine is acquired, the fuel injection mode of the engine may be adjusted according to the current temperature of the coolant.

[0058] Regarding the above S102, it can be understood that the above preset temperature threshold can be set according to actual needs, for example, the preset temperature threshold can be set to -20°C.

[0059] Further, when it is determined that the current temperature of the coolant is less than or equal to the preset temperature threshold, it can be considered that the engine is at an extremely low temperature, and starting the engine at an extremely low temperature is called "engine cold start".

[0060] As mentioned above, if the GDI single injection starting effect is poor, the GDI multiple injection method is usually used to optimize the cold start. However, when performing a cold start using the GDI multiple injection method, problems such as low starter drag speed, limited oil pumping capacity of the high-pressure oil pump, and gradual decrease in oil pressure in the high-pressure oil rail may occur, resulting in engine cold start failure.

[0061] The PFI system injects fuel into the intake manifold instead of directly into the cylinder, and can use the heat of the intake manifold to help the fuel evaporate. In addition, the PFI system usually does not require as high an injection pressure as the GDI system, so even under low temperature conditions, it is easier to achieve the required injection pressure using the PFI system for fuel injection. Based on this, GDI+PFI injection can be used during cold engine start to increase the success rate of cold engine start.

[0062] Furthermore, currently, engines equipped with a dual injection system usually determine which injection method to use for fuel injection based on the current speed of the engine.

[0063] It is understandable that the current speed of the above engine can usually be measured by a crankshaft position sensor, with the unit being revolutions per minute (RPM).

[0064] When the current engine speed is low, the intake air flow velocity is relatively low. The PFI system can inject fuel into the intake manifold, giving the fuel and air enough time to fully mix and form a more uniform mixture. This uniform mixture is conducive to stable combustion and improved combustion efficiency. In other words, when the current engine speed is low, the port injection nozzle can be used for fuel injection.

[0065] When the current engine speed is high, the engine needs more air and fuel to generate more power. The GDI system can inject fuel directly into the cylinder, which can achieve higher injection pressure, better fuel atomization, and faster mixing with air. In other words, when the current engine speed is high, direct injection nozzles can be used for fuel injection.

[0066] It is understandable that when the engine is started at an extremely low temperature, fuel injection may be carried out simultaneously using the airway injection nozzle and the direct injection nozzle. The ratio between the injection amounts of the engine's direct injection nozzle and the airway injection nozzle when injecting fuel can be determined based on the current engine speed and the current temperature of the coolant, that is, the above-mentioned first target injection amount ratio.

[0067] In some embodiments, when the current engine speed is low and the current coolant temperature is low, the proportion of the fuel injection amount of the airway injection nozzle in the first target fuel injection amount ratio can be increased. As the engine speed increases and the coolant temperature increases, the proportion of the fuel injection amount of the direct injection nozzle in the first target fuel injection amount ratio can be increased.

[0068] It is understandable that, as mentioned above, when the engine speed is low, the intake air flow speed is relatively slow and the mixture formation time is long. At this time, the injection amount ratio of the airway injection nozzle can be appropriately increased to utilize the air flow in the airway to better atomize the fuel and promote the formation of the mixture. As the engine speed increases, the intake air flow speed increases and the mixture formation time is shortened. The direct injection nozzle can inject fuel directly into the cylinder more quickly and improve combustion efficiency. Therefore, at high speeds, the injection amount ratio of the direct injection nozzle can be appropriately increased.

[0069] When the coolant temperature is low, the engine is in a cold start state. At this time, in order to ensure good combustion stability, the injection amount ratio of the airway injection nozzle can be increased. The fuel injected by the airway can be preheated in the intake duct, which helps to increase the temperature of the mixture and promote combustion. When the coolant temperature rises to the normal operating temperature, the combustion conditions of the engine improve. According to different working conditions, the injection amount ratio of the direct injection nozzle can be reasonably adjusted to improve the power, economy and emission performance of the engine.

[0070] In other embodiments, a mapping relationship between the engine speed, coolant temperature and the injection amount ratio of the direct injection nozzle and the airway injection nozzle can be established through experiments and data analysis. This relationship can be expressed using two-dimensional tables, curve fitting and other methods.

[0071] In one possible implementation, based on the current temperature of the coolant and the current speed of the engine, a first target fuel injection amount ratio between the fuel injection amounts of the direct injection nozzle and the airway injection nozzle of the engine when performing fuel injection is determined, including: based on a first preset corresponding relationship, determining the first target fuel injection amount ratio corresponding to the current temperature and the current speed; wherein the first preset corresponding relationship is a corresponding relationship between a target parameter and a target fuel injection amount ratio; the target parameters include the temperature of the coolant and the speed of the engine; the target fuel injection amount ratio is the fuel injection amount ratio between the direct injection nozzle and the airway injection nozzle when performing fuel injection.

[0072] It can be understood that the above-mentioned first preset corresponding relationship can be obtained based on an actual engine cold start test, and the first preset corresponding relationship can be stored in the engine controller.

[0073] For example, according to an actual engine cold start test, data of the best starting effect corresponding to different coolant temperatures and different engine speeds can be obtained, and the proportion of the PFI injection amount corresponding to the current coolant temperature and the current engine speed can be shown in Table 1:

[0074] Table 1

[0075]

[0076] As shown in Table 1 above, the proportion of the PFI injection amount can be determined according to the current temperature of the coolant and the current speed of the engine.

[0077] Among them, the above-mentioned proportion of PFI injection amount refers to the proportion of the injection amount of the airway injection nozzle of the PFI system to the total injection amount required for engine starting. The total injection amount required for engine starting is the sum of the injection amount of the airway injection nozzle of the PFI system and the injection amount of the direct injection nozzle of the GDI system.

[0078] In the above-mentioned case where the current speed of the engine exceeds 1000RPM, since the direct injection nozzle of the GDI system can use less injection amount to maintain the operation of the engine compared with the airway injection nozzle of the PFI system, when the current speed of the engine is greater than or equal to 1000RPM, the airway injection nozzle of the PFI system can no longer be used for fuel injection.

[0079] In the above-mentioned case where the current temperature of the coolant is -10°C, since the engine is not at an extremely low temperature, the GDI multiple injection strategy can be used, and there is no need to use the airway injection nozzle of the PFI system for fuel injection. Then, when the current temperature of the coolant is greater than or equal to -10°C, the airway injection nozzle of the PFI system can no longer be used for fuel injection.

[0080] For example, if the current temperature of the coolant is -30°C and the current speed of the engine is 200RPM, by querying Table 1, it can be determined that the proportion of the PFI injection amount is 0.4. Accordingly, it can be obtained that the proportion of the GDI injection amount is 0.6. That is, the first target injection amount ratio between the injection amount of the direct injection nozzle and the airway injection nozzle of the above engine when performing fuel injection is determined to be 3:2.

[0081] The above method determines the first target fuel injection ratio based on the current temperature of the coolant and the current speed of the engine, which can make the fuel injection amount of the direct injection nozzle and the airway injection nozzle more in line with the actual operation requirements of the engine, and can make the mixed gas reach a more ideal state under different working conditions, thereby improving the utilization rate of fuel and reducing fuel consumption. By reasonably adjusting the fuel injection ratio between the direct injection nozzle and the airway injection nozzle, it can also ensure that the engine obtains appropriate fuel supply under various working conditions, thereby improving the success rate of cold starting of the engine.

[0082] Further, after the first target fuel injection amount ratio is determined, the engine can be controlled to perform fuel injection according to the first target fuel injection amount ratio.

[0083] Regarding the above S103, it can be understood that after determining the above-mentioned first target injection amount ratio, the engine controller can control the injection pulse width of the direct injection nozzle and the airway injection nozzle so that the direct injection nozzle and the airway injection nozzle can perform fuel injection according to the first target injection amount ratio.

[0084] The above-mentioned injection pulse width refers to the length of time that the injector is turned on to inject fuel.

[0085] For example, the injection pulse width can be controlled by adjusting the opening time and closing time of the injector.

[0086] In order to enable the injector to achieve the best fuel injection effect and help the engine start smoothly, the injector can be controlled to spray fuel when the fuel pressure in the engine reaches a preset pressure.

[0087] In one possible implementation, the direct injection nozzle and the airway injection nozzle are controlled to perform fuel injection according to the first target fuel injection amount ratio to control the cold start of the engine, including: based on the current temperature of the coolant, determining the target oil pressure corresponding to the current temperature; controlling the fuel pump of the engine to adjust the fuel pressure inside the engine; and when it is determined that the fuel pressure inside the engine reaches the target oil pressure, controlling the direct injection nozzle and the airway injection nozzle to perform fuel injection according to the first target fuel injection amount ratio to control the cold start of the engine.

[0088] It can be understood that the above-mentioned target oil pressure refers to the fuel pressure value that the engine's fuel system hopes to achieve.

[0089] Furthermore, a correspondence between the temperature of the coolant and the target oil pressure may be established in advance, and after the current temperature of the coolant is acquired, the target oil pressure may be determined based on the correspondence.

[0090] For example, the corresponding relationship between the temperature of the coolant and the target oil pressure may be shown in Table 2:

[0091] Table 2

[0092]

[0093] As shown in Table 2, as the current temperature of the coolant increases, the target oil pressure gradually increases.

[0094] For example, if the current temperature of the coolant is obtained to be -20°C, through the above Table 2, it can be determined that the target oil pressure corresponding to this temperature is 14 MPa.

[0095] Furthermore, after determining the target oil pressure, the engine controller may control the fuel pump to adjust the current fuel pressure inside the engine.

[0096] In some embodiments, after determining the target fuel pressure, the engine controller can detect the current fuel pressure inside the engine through the fuel pressure sensor, and then compare the detected current fuel pressure with the target fuel pressure. If the current fuel pressure is lower than the target fuel pressure, it is determined that the fuel pump needs to be controlled to increase the fuel pressure; if the current fuel pressure is higher than the target fuel pressure, it is determined that the fuel pump needs to be controlled to reduce the fuel pressure.

[0097] It is understandable that the above-mentioned fuel pressure sensor can be installed on the fuel rail and can monitor the oil pressure in the fuel rail in real time.

[0098] The above-mentioned control of the fuel pump to increase or decrease the oil pressure can usually be achieved by controlling the speed of the motor of the fuel pump, and can also be achieved by controlling the return oil volume of the oil return valve.

[0099] For example, if it is determined that the fuel pump needs to be controlled to increase the oil pressure, the speed of the motor of the fuel pump can be increased to increase the output pressure of the fuel pump, and the return oil valve can be controlled to reduce the return oil volume to increase the oil pressure.

[0100] If it is determined that the fuel pump needs to be controlled to reduce the oil pressure, the speed of the fuel pump can be reduced to reduce the output pressure of the fuel pump. The return oil valve can also be controlled to increase the return oil volume to reduce the oil pressure.

[0101] The above method determines the target oil pressure based on the current temperature and controls the fuel pump to adjust the fuel pressure, so that the fuel has a higher pressure when injected, thereby improving the atomization effect of the fuel. Better atomization can make the fuel and air mix more fully, improve the stability and reliability of combustion, and help the engine reach a stable operating state faster during cold start. By accurately controlling the fuel pressure to reach the target oil pressure, the direct injection nozzle and the airway injection nozzle can perform fuel injection according to the first target injection amount ratio, ensuring that the mixture concentration is within an appropriate range, and improving the success rate of engine cold start.

[0102] Furthermore, when it is determined that the fuel pressure inside the engine reaches the target oil pressure, the direct injection nozzle and the airway injection nozzle can be controlled to perform fuel injection according to the first target fuel injection amount ratio.

[0103] In one possible implementation, controlling the direct injection nozzle and the airway injection nozzle to perform fuel injection according to the first target fuel injection amount ratio includes: determining the total fuel injection amount required for the engine cold start; based on the total fuel injection amount and the first target fuel injection amount ratio, determining the first fuel injection amount corresponding to the direct injection nozzle, and determining the second fuel injection amount corresponding to the airway injection nozzle; wherein the sum of the first fuel injection amount and the second fuel injection amount is the total fuel injection amount; controlling the direct injection nozzle to perform fuel injection according to the first fuel injection amount, and controlling the airway injection nozzle to perform fuel injection according to the second fuel injection amount.

[0104] It is understandable that the total amount of fuel injection required for the cold start of the engine can be determined based on the current state parameters of the engine, which may include the current temperature of the coolant, the speed of the engine, the amount of air entering the engine, and the air temperature.

[0105] In some embodiments, a basic fuel injection amount required for normal engine starting is obtained, a correction factor is determined based on current state parameters of the engine, and then a total fuel injection amount required for cold engine starting is determined based on the basic fuel injection amount and the correction factor.

[0106] It can be understood that the above basic fuel injection amount can be determined according to the air mass entering the engine and the target air-fuel ratio.

[0107] The mass of air entering the engine can be estimated by the engine controller based on the pressure of the intake manifold or the data of the air flow meter. For most gasoline engines, the standard theoretical air-fuel ratio is 14.7:1, that is, the above target air-fuel ratio can be 14.7:1.

[0108] Furthermore, since the current temperature of the coolant and the intake temperature of the air entering the engine are both low, the volatility of the fuel in the engine becomes worse, and the difficulty of forming the mixture increases. In this case, it may be necessary to increase the injection amount more than at normal operating temperature to ensure smooth engine starting.

[0109] For example, the proportion of the amount of fuel injection that needs to be increased to ensure smooth engine starting at the current operating temperature can be determined based on empirical data or a pre-established model. For example, based on the current temperature of the coolant and the intake temperature of the air entering the engine, it is determined that 10% more fuel injection is required at the current operating temperature than at the normal operating temperature to ensure smooth engine starting, that is, the temperature correction coefficient can be determined to be 1.1.

[0110] When the current engine speed is too low, it means that the engine needs more power to accelerate to the normal operating speed. In this case, in order to ensure the smooth start of the engine, it may be necessary to increase the injection amount by a certain proportion.

[0111] For example, the proportion of the amount of fuel injection that needs to be increased to ensure the smooth start of the engine at the current speed can be determined based on empirical data or a pre-established model. For example, based on the current speed of the engine, it is determined that 20% more fuel injection is required at the current speed than at the normal speed to ensure the smooth start of the engine, that is, the speed correction coefficient can be determined to be 1.2.

[0112] For example, if the mass of air entering the engine is 100 grams, the target air-fuel ratio is 14.7:1, and the gasoline density is 0.72 grams / ml, the basic injection amount is calculated to be 9.444 ml. If the temperature correction coefficient is determined to be 1.1 and the speed correction coefficient is 1.2, the comprehensive correction coefficient can be calculated to be 1.1*1.2=1.32, and the corrected total injection amount is calculated to be 9.444*1.32=12.47 ml, that is, the total injection amount required for cold start of the engine is 12.47 ml.

[0113] Further, after the total amount of fuel injection required for the cold start of the engine is determined, the total amount of fuel injection may be allocated according to the first target fuel injection amount ratio determined previously.

[0114] For example, if the total amount of fuel injection required for cold start of the engine is determined to be 10 ml, the first target fuel injection amount ratio is determined to be 3:2, that is, the fuel injection amount of the direct injection nozzle accounts for 60% of the total amount of fuel injection, and the fuel injection amount of the airway injection nozzle accounts for 40% of the total amount of fuel injection. According to the total amount of fuel injection and the first target fuel injection ratio, the first fuel injection amount corresponding to the direct injection nozzle can be determined to be 6 ml, and the second fuel injection amount corresponding to the airway injection nozzle can be determined to be 4 ml.

[0115] Furthermore, after determining the first fuel injection amount corresponding to the above-mentioned direct injection nozzle and the second fuel injection amount corresponding to the airway injection nozzle, the engine controller can control the direct injection nozzle to inject 6 ml of fuel and control the airway injection nozzle to inject 4 ml of fuel, ensuring that the sum of the two is the required total fuel injection amount of 10 ml.

[0116] During the cold start of the engine, the GDI system can perform fuel injection in a single injection mode or in a multiple injection mode.

[0117] In some embodiments, the injection mode of the GDI system may be determined based on the current temperature of the coolant and the current speed of the engine.

[0118] For example, if it is determined that the current temperature of the coolant is less than or equal to a preset temperature threshold and the current speed of the engine is less than or equal to a preset speed threshold, it can be determined that the injection mode of the GDI system is multiple injections.

[0119] The preset temperature threshold can be set according to actual needs, such as -20°C; the preset speed threshold can also be set according to actual needs, such as 600RPM.

[0120] In some embodiments, during the cold start of the engine, the engine controller may set the initial injection number of the GDI system when the current temperature of the coolant is less than or equal to a preset temperature threshold and the current speed of the engine is less than or equal to a preset speed threshold. Then, it may be determined whether to adjust the initial injection number according to the operating state of the engine.

[0121] Exemplarily, the above-mentioned initial injection times can be set according to actual needs, for example, the initial injection times can be set to two.

[0122] If the engine has unstable combustion, large speed fluctuations or unsatisfactory emission indicators, the number of injections can be gradually increased based on the initial number of injections. Specifically, one injection can be added each time the above situation occurs until the engine runs smoothly.

[0123] On the contrary, if the engine has a mixture concentration that is too high, a decrease in combustion efficiency, or other abnormal conditions during combustion, the number of injections can be reduced based on the initial number of injections. Specifically, one injection can be reduced each time the above situation occurs until the engine runs smoothly.

[0124] In other embodiments, a model for predicting the number of injections is established using experimental data of the engine and a preset machine learning model, and the model can be stored in an engine controller of the vehicle. During a cold start of the engine, the engine controller inputs the current state parameters of the engine into the model, and the model can output a predicted number of injections.

[0125] It can be understood that the above-mentioned model for predicting the number of injections can be trained based on various engine state parameters such as engine temperature, speed, load, fuel characteristics, and the number of injections corresponding to various engine state parameters, and the model has been verified and optimized through a large number of experiments.

[0126] For example, if the temperature of the engine coolant is obtained to be -30°C, the temperature of the gas entering the engine is -25°C, the engine speed is 300RPM, and the fuel in the engine is low-volatility fuel, these parameters are input into the model for predicting the number of injections, and the predicted number of injections can be obtained as three.

[0127] It should be understood that as the engine operating state changes, the engine controller will continuously update the input parameters of the above-mentioned model for predicting the number of injections to adjust the number of injections of the GDI system in real time.

[0128] Further, when it is determined that the injection mode of the above-mentioned GDI system is multiple injections, the ratio between the injection amounts of each injection of the direct injection nozzle can be determined.

[0129] In one possible implementation, controlling the direct injection nozzle to perform fuel injection according to the first injection amount includes: when it is determined that the direct injection nozzle performs fuel injection multiple times, determining a second target injection amount ratio corresponding to the current temperature of the coolant based on a second preset correspondence; wherein the second preset correspondence is a correspondence between the temperature of the coolant and the injection amount ratio of each injection during multiple fuel injections; the second target injection amount ratio is a ratio between the injection amounts of each injection during multiple fuel injections by the direct injection nozzle; based on the first injection amount and the second target injection amount ratio, determining a single injection amount each time the direct injection nozzle performs fuel injection; and controlling the direct injection nozzle to perform fuel injection according to the single injection amount each time fuel injection is performed.

[0130] It is understandable that when it is determined that the number of times the direct injection nozzle performs fuel injection is multiple, it means that the direct injection nozzle will perform multiple fuel injections in the current working cycle of the engine. The single injection amount of each fuel injection performed by the direct injection nozzle can be determined based on the first injection amount.

[0131] The second preset corresponding relationship may be obtained based on the results of experimental tests, and the second preset relationship may be a pre-set relationship table, which may be stored in the engine controller of the vehicle.

[0132] For example, according to an actual engine cold start test, the ratio between the injection amount of each injection during multiple fuel injections by the direct injection nozzle when the starting effect is best at different coolant temperatures can be obtained.

[0133] The above-mentioned second preset corresponding relationship may include multiple groups of corresponding relationships, specifically including the ratio between the injection amounts of each injection during two fuel injections, and may also include the ratio between the injection amounts of each injection during three or more fuel injections.

[0134] Further, according to the currently determined number of times the direct injection nozzle performs fuel injection, a corresponding relationship of the corresponding number of times can be searched in the above-mentioned second preset relationship.

[0135] For example, if it is determined that the number of times the direct injection nozzle performs fuel injection is two, the corresponding relationship between the current temperature of the coolant and the ratio of the injection amount of each injection during the two fuel injections can be found in the second preset relationship.

[0136] For example, the corresponding relationship between the current temperature of the coolant and the ratio of the fuel injection amount of each injection during the two fuel injections can be shown in Table 3:

[0137] Table 3

[0138]

[0139] The injection ratio in Table 3 refers to the ratio between the injection amount of the first fuel injection by the direct injection nozzle and the injection amount of the second fuel injection by the direct injection nozzle.

[0140] It is understandable that as the coolant temperature gradually increases, the atomization effect of the fuel becomes better and better, and the proportion of the second injection can be appropriately increased to make full use of the higher temperature to promote combustion. Therefore, as the current temperature of the coolant increases, the proportion of the second fuel injection of the direct injection nozzle tends to increase. However, when the current temperature of the coolant reaches 80°C, the volatility of the fuel is relatively good, and a single injection can provide enough fuel at the right time to form a combustible mixture. Therefore, the direct injection nozzle no longer performs multiple fuel injections, but injects fuel in a single injection.

[0141] For example, if it is determined that the GDI system performs fuel injection twice, the corresponding relationship between the current temperature of the coolant and the ratio of the injection amount of each injection during the two fuel injections is searched in the second preset relationship. If the current temperature of the coolant is obtained to be -30°C, based on the corresponding relationship, it can be determined that the ratio of the injection amount of the two fuel injections is 8:2.

[0142] Further, if the first fuel injection amount corresponding to the determined direct injection nozzle is 10 ml, based on the ratio of the fuel injection amounts of the above two fuel injections, it can be determined that the fuel injection amount of the direct injection nozzle for the first time is 8 ml, and the fuel injection amount of the direct injection nozzle for the second time is 2 ml. Then the direct injection nozzle can be controlled to inject 8 ml of fuel for the first time and 2 ml of fuel for the second time.

[0143] In order to improve the success rate of engine cold start, the direct injection nozzle and the airway injection nozzle can also be controlled to inject fuel at the appropriate time.

[0144] In one possible implementation, the direct injection nozzle is controlled to inject fuel according to the first injection amount, and the airway injection nozzle is controlled to inject fuel according to the second injection amount, including: determining a first injection time when the direct injection nozzle injects fuel, and determining a second injection time when the airway injection nozzle injects fuel; controlling the direct injection nozzle to inject fuel according to the first injection amount at the first injection time, and controlling the airway injection nozzle to inject fuel according to the second injection amount at the second injection time.

[0145] It can be understood that the above-mentioned first injection timing refers to the timing when the direct injection nozzle starts to inject fuel; the above-mentioned second injection timing refers to the timing when the airway injection nozzle starts to inject fuel.

[0146] The moment of fuel injection can be expressed by the rotation angle of the crankshaft relative to the compression top dead center. The compression top dead center is a specific position in the engine working cycle. During the compression stroke of the engine, the position where the piston moves to the highest point is called the compression top dead center. At this time, the piston is completely at the top of the cylinder. The crankshaft is a mechanical component in the engine that converts the linear reciprocating motion of the piston into rotational motion. The rotation angle of the crankshaft relative to the compression top dead center can be used to describe the time when various events occur inside the engine.

[0147] In some embodiments, when the rotation angle of the crankshaft relative to the compression top dead center is a positive value, it means that the crankshaft has rotated a certain angle from the compression top dead center, that is, the crankshaft is at a position after the compression top dead center; when the rotation angle of the crankshaft relative to the compression top dead center is a negative value, it means that the crankshaft has not reached the compression top dead center, that is, the crankshaft is at a position before the compression top dead center.

[0148] Furthermore, the first injection timing and the second injection timing may be set according to actual operating conditions of the engine.

[0149] For example, in the initial stage of cold start of the engine, the current temperature of the coolant is low and the current speed of the engine is low. At this time, the volatility of the fuel is poor and it is not easy to become a gas, so it is difficult to form a uniform mixture with the air. The airway injection nozzle usually injects the fuel into the intake manifold or the intake port. The temperature of this area is higher than that in the cylinder, which helps the fuel to volatilize and atomize better. In addition, the position of the airway injection nozzle is close to the intake port, so the fuel has more time to mix with the air before entering the cylinder, which helps to improve the combustion effect.

[0150] Therefore, in the initial stage of the engine cold start, the airway injection nozzle can be controlled to perform fuel injection. That is, the second injection timing can be the start timing of the engine cold start.

[0151] As the temperature of the coolant increases, the volatility of the fuel increases and it is easier to atomize. At this time, the fuel is directly injected into the cylinder through the direct injection nozzle, and the fuel in the cylinder can be fully mixed with the air, thereby improving the combustion efficiency. Under high temperature conditions, the fuel injected by direct injection is more likely to form a uniform mixture with the air, which helps to improve the combustion efficiency. Therefore, as the temperature of the coolant increases, the direct injection nozzle can be controlled to inject fuel.

[0152] For example, a second preset temperature threshold may be set, and when the temperature of the coolant rises to a value greater than or equal to the second preset temperature threshold, the direct injection nozzle may be controlled to perform fuel injection. That is, the first injection time may be the time when the temperature of the coolant rises to a value greater than or equal to the second preset temperature threshold.

[0153] Furthermore, the injection timing of the direct injection nozzle is usually affected by the operating parameters of the engine, such as the speed and load of the engine.

[0154] In one possible implementation, determining the first injection time when the direct injection nozzle performs fuel injection includes: obtaining the current operating parameters of the engine; wherein the current operating parameters include the current speed and the current load; based on a third preset correspondence, determining the target start time for the direct injection nozzle to perform fuel injection corresponding to the current operating parameters; wherein the third preset correspondence is the correspondence between the operating parameters and the start time for the direct injection nozzle to perform fuel injection; the operating parameters include the speed and the load; based on a fourth preset correspondence, determining the target end time for the direct injection nozzle to perform fuel injection corresponding to the current operating parameters; wherein the fourth preset correspondence is the correspondence between the operating parameters and the end time for the direct injection nozzle to perform fuel injection; when it is determined that the number of injections when the direct injection nozzle performs fuel injection is multiple times, based on the target start time and the target end time, determine the first injection time each time the direct injection nozzle performs fuel injection.

[0155] It can be understood that, as mentioned above, the rotation speed of the above engine is usually measured by a crankshaft position sensor, and the unit is revolutions per minute (RPM).

[0156] The above current load is usually estimated by a throttle position sensor, an intake manifold absolute pressure sensor, etc., and is used to reflect the load state of the engine, and is usually expressed in percentage.

[0157] The third preset corresponding relationship may be obtained based on the results of experimental tests, and the third preset relationship may be a pre-set relationship table, which may be stored in the engine controller of the vehicle.

[0158] The third preset corresponding relationship is used to represent the relationship between the operating parameters of the engine (including the engine speed and load) and the start time of the direct injection nozzle to perform fuel injection.

[0159] Exemplarily, the third preset correspondence between the operating parameters of the engine and the start time of the direct injection nozzle for fuel injection may be as shown in Table 4:

[0160] Table 4

[0161]

[0162] As mentioned above, the injection time of the fuel can be expressed by the rotation angle of the crankshaft relative to the compression top dead center. The start time of the fuel injection of the above-mentioned direct injection nozzle can actually be expressed by the rotation angle of the crankshaft relative to the compression top dead center. For example, if the start time of the fuel injection is determined to be 310 degrees, it means that the fuel injection starts when the crankshaft rotates to an angle of 310 degrees relative to the compression top dead center.

[0163] For example, after obtaining the current speed and current load of the engine, the corresponding target start time of fuel injection can be queried in the above Table 4. For example, if the current speed of the engine is 400RPM and the current load is 20%, it can be determined that the start of fuel injection occurs at 300 degrees after the crankshaft rotates to the compression top dead center.

[0164] Similarly, the fourth preset corresponding relationship may be obtained based on the results of experimental tests, and the fourth preset relationship may be a pre-set relationship table, which may be stored in the engine controller of the vehicle.

[0165] The fourth preset corresponding relationship is used to represent the relationship between the operating parameters of the engine (including the engine speed and load) and the end time of the fuel injection by the direct injection nozzle.

[0166] Exemplarily, the fourth preset correspondence between the operating parameters of the engine and the end time of the direct injection nozzle performing fuel injection may be as shown in Table 5:

[0167] Table 5

[0168]

[0169] As mentioned above, the fuel injection time can be expressed by the rotation angle of the crankshaft relative to the compression top dead center. The end time of the fuel injection of the above-mentioned direct injection nozzle can actually also be expressed by the rotation angle of the crankshaft relative to the compression top dead center. For example, if the end time of the fuel injection is determined to be 100 degrees, it means that the fuel injection ends when the crankshaft rotates to an angle of 100 degrees relative to the compression top dead center.

[0170] For example, after obtaining the current speed and current load of the engine, the corresponding target end time of fuel injection can be queried in the above Table 5. For example, if the current speed of the engine is 400RPM and the current load is 20%, it can be determined that the end of fuel injection occurs at a position 80 degrees after the crankshaft rotates to the compression top dead center.

[0171] Furthermore, when it is determined that the number of injections of the direct injection nozzle is multiple, the above-mentioned target starting time is actually the starting time of the first fuel injection of the direct injection nozzle, and the above-mentioned target ending time is actually the ending time of the last fuel injection of the direct injection nozzle.

[0172] Based on this, when it is determined that the number of times the direct injection nozzle performs fuel injection is multiple times, the start time of each fuel injection of the direct injection nozzle, that is, the first injection time of each fuel injection, can be determined according to the above-mentioned target start time and target end time.

[0173] In some embodiments, the specific time of each injection of the direct injection nozzle can be allocated according to the time interval between the target start time and the target end time and the determined number of injections of the direct injection nozzle.

[0174] Specifically, the target start time is subtracted from the target end time to obtain the total time span, and then the total time span is divided by the number of injections to obtain the average time interval between each injection.

[0175] For example, if the target starting time is 300 degrees, that is, the start of fuel injection occurs 300 degrees after the crankshaft rotates to the compression top dead center, and the target ending time is 80 degrees, that is, it is determined that the end of fuel injection occurs 80 degrees after the crankshaft rotates to the compression top dead center, and the number of injections of the direct injection nozzle is determined to be 2 times, then the total angle span is first calculated to be 220 degrees, and then the two injections are evenly distributed, so that the average angle span between each injection is 110 degrees, and then it can be determined that the first fuel injection occurs 300 degrees after the crankshaft rotates to the compression top dead center, and the position of the second fuel injection can be 300 degrees - 110 degrees = 190 degrees, that is, the second fuel injection occurs 190 degrees after the crankshaft rotates to the compression top dead center.

[0176] In other embodiments, the correspondence between the operating parameters of the engine and the injection timing may be pre-established, and the start timing of each injection by the direct injection nozzle may be determined according to the current operating parameters of the engine.

[0177] It can be understood that the specific establishment method is similar to the establishment method of the third preset corresponding relationship and the fourth preset corresponding relationship mentioned above, and will not be described in detail here.

[0178] The above method determines the target start time and target end time of the direct injection nozzle for fuel injection based on the current speed and current load of the engine, so that the fuel can be injected into the cylinder at the best time point. When the number of injections of the direct injection nozzle is determined to be multiple times, the first injection time of each time is determined based on the target start time and target end time, which can achieve more precise fuel injection control. In addition, the injection time of the above direct injection nozzle is dynamically adjusted according to the actual working conditions to ensure that the engine can perform at its best under various working conditions and improve the reliability of the engine.

[0179] Furthermore, in addition to determining the first injection timing of the direct injection nozzle for fuel injection, the second injection timing of the airway injection nozzle for fuel injection may also be determined.

[0180] It is understandable that when injecting fuel when the valve is open, the fuel will directly enter the cylinder, and the air flow conditions in the cylinder at this time are not conducive to the full mixing of fuel and air. Therefore, the PFI system usually avoids controlling the port injection nozzle to perform fuel injection when the valve is open.

[0181] If the port injection nozzle is injected when the intake valve is closed, the fuel may not have enough time to fully mix with the air, thus affecting the combustion effect. Based on this, when determining the second injection timing, a suitable time can be found between the opening and closing of the valve, and the second injection timing can ensure that the fuel and air are fully mixed and a uniform mixture can be formed when entering the cylinder.

[0182] In one possible implementation, determining the second injection timing when the airway injection nozzle performs fuel injection includes: obtaining the opening timing of the intake valve of the engine, and obtaining the injection delay angle when the airway injection nozzle performs fuel injection; wherein the injection delay angle is the crankshaft angle between the start timing of the fuel injection of the airway injection nozzle and the opening timing of the intake valve; based on the opening timing of the intake valve and the injection delay angle, determining the second injection timing when the airway injection nozzle performs fuel injection.

[0183] It is understandable that the opening time of the intake valve can be expressed by the rotation angle of the crankshaft relative to the compression top dead center. The opening time of the intake valve can be determined by a camshaft position sensor.

[0184] The above-mentioned injection delay angle refers to the crankshaft angle between the moment when the airway injection nozzle starts to inject fuel and the moment when the intake valve opens.

[0185] The injection delay angle may be determined based on current operating parameters of the engine, such as the current temperature of the coolant, the temperature of the air entering the engine, and the current speed of the engine.

[0186] In one possible implementation, obtaining the injection delay angle of the airway injection nozzle when performing fuel injection includes: obtaining the current temperature of the coolant, the intake temperature of the air entering the intake manifold of the engine, and the current speed of the engine; and determining the injection delay angle based on the current temperature of the coolant, the intake temperature, and the current speed of the engine.

[0187] It is understood that the current temperature of the coolant can be measured by a coolant temperature sensor. The intake temperature of the air entering the intake manifold of the engine can be measured by a temperature sensor. The current speed of the engine can be measured by a crankshaft position sensor.

[0188] Furthermore, a fifth preset corresponding relationship between the coolant temperature, the intake air temperature and the engine speed and the injection delay angle may be pre-established, and the fifth preset corresponding relationship may be obtained through actual experimental data and simulation analysis.

[0189] For example, if the current temperature of the coolant is -20°C, the intake air temperature is -15°C, and the current engine speed is 200RPM, based on the fifth preset corresponding relationship, it can be determined that the corresponding injection delay angle is 10 degrees.

[0190] Further, after the above-mentioned injection delay angle is determined, the second injection timing of the port injection nozzle for performing fuel injection can be determined based on the opening timing of the intake valve and the injection delay angle.

[0191] For example, if the intake valve opens when the crankshaft rotates to an angle of -20 degrees relative to the compression top dead center, the injection delay angle is 10 degrees, that is, the crankshaft angle between the moment when the airway injection nozzle starts to inject fuel and the moment when the intake valve opens is 10 degrees, then it can be determined that the airway injection nozzle starts to inject fuel when the crankshaft rotates to an angle of -10 degrees relative to the compression top dead center.

[0192] The above method determines the second injection timing of the airway injection nozzle for fuel injection based on the intake valve opening timing and the injection delay angle, so that the fuel can be injected into the intake duct at the most appropriate time and fully mixed with the intake air flow to form a uniform mixture, thereby ensuring that the mixture reaches the optimal state when entering the cylinder, improving combustion efficiency, and thereby improving the success rate of engine cold start.

[0193] In some embodiments, after the current temperature of the coolant is acquired, different fuel injection methods may be adopted based on the current temperature of the coolant to control the engine start.

[0194] For example, Figure 2 It is a schematic flow chart of an engine starting method provided in an embodiment of the present application.

[0195] like Figure 2 As shown, the method 200 includes:

[0196] S201, obtaining the current temperature of the coolant in the engine of the vehicle.

[0197] It is understandable that the current temperature of the coolant in the engine may also be referred to as the starting water temperature of the engine. The current temperature of the coolant in the engine is usually measured by a coolant temperature sensor.

[0198] S202: When the current temperature of the coolant is less than or equal to a first preset temperature threshold, a GDI+PFI dual injection injection mode is used to perform fuel injection to control the engine start.

[0199] It can be understood that the first preset temperature threshold can be the same as the preset temperature threshold mentioned above, and the first preset temperature threshold can be set according to actual needs, such as being set to -20°C.

[0200] When the current temperature of the coolant is less than or equal to the first preset temperature threshold, the engine start is a cold start at an extremely low temperature.

[0201] S203, when the current temperature of the coolant is greater than the first preset temperature threshold and less than the second preset temperature threshold, fuel injection is performed using a GDI multiple injection injection method to control the engine start.

[0202] It can be understood that the second preset temperature threshold can also be set according to actual needs. The second preset temperature threshold can be set to be larger than the first temperature threshold, for example, set to 80°C.

[0203] When it is determined that the current temperature is greater than the first preset temperature threshold and less than the second preset temperature threshold, the engine start is a cold start at a non-extremely low temperature.

[0204] S204: When the current temperature of the coolant is greater than or equal to the second preset temperature threshold, fuel injection is performed using a GDI single injection injection mode to control the engine start.

[0205] It can be understood that when it is determined that the current temperature is greater than or equal to the second preset temperature threshold, the engine has approached or reached the normal operating temperature, and the engine can be started smoothly using the GDI single injection.

[0206] In the above method, when it is determined that the current temperature is less than or equal to the first preset temperature threshold, the dual injection strategy of direct injection nozzle and port injection nozzle co-injection, i.e., the injection mode of GDI+PFI dual injection, can control the port injection nozzle in the intake manifold injection system to spray fuel into the intake manifold, and with the help of the intake airflow, better disperse the fuel, form a more uniform mixture, improve the combustion efficiency, and thus start the engine faster. When it is determined that the current temperature is greater than the first preset temperature threshold and less than the second preset temperature threshold, the GDI multiple injection strategy, i.e., the injection mode of GDI multiple injection, can improve the fuel atomization level, make the mixture in the cylinder uniform, be more conducive to the ignition of the spark plug and successful starting, and improve fuel economy. When it is determined that the current temperature is greater than or equal to the second preset temperature threshold, the atomization effect of the fuel is better, a single injection is sufficient to form a good mixture, and multiple injections are not required. In addition, a single injection can better control the injection amount and injection timing, optimize the combustion process, and improve the combustion efficiency.

[0207] Figure 3 It is a structural schematic diagram of a cold start device for an engine provided in an embodiment of the present application.

[0208] For example, Figure 3 As shown, the device 300 includes:

[0209] The acquisition module 301 is used to acquire the current temperature of the coolant in the engine of the vehicle.

[0210] The determination module 302 is used to obtain the current speed of the engine when the current temperature is less than or equal to a preset temperature threshold, and determine a first target injection amount ratio between the injection amounts of the direct injection nozzle and the airway injection nozzle of the engine when performing fuel injection based on the current temperature of the coolant and the current speed of the engine.

[0211] The control module 303 is used to control the direct injection nozzle and the airway injection nozzle to perform fuel injection according to the first target fuel injection amount ratio to control the cold start of the engine.

[0212] In one possible implementation, the determination module is specifically used to: determine a first target fuel injection amount ratio corresponding to the current temperature and the current speed based on a first preset corresponding relationship; wherein the first preset corresponding relationship is a corresponding relationship between a target parameter and a target fuel injection amount ratio; the target parameter includes the temperature of the coolant and the speed of the engine; the target fuel injection amount ratio is the fuel injection amount ratio when the direct injection nozzle and the airway injection nozzle perform fuel injection.

[0213] In one possible implementation, the control module is specifically used to: determine the total amount of fuel injection required for the cold start of the engine; based on the ratio of the total amount of fuel injection and the first target fuel injection amount, determine the first fuel injection amount corresponding to the direct injection nozzle, and determine the second fuel injection amount corresponding to the airway injection nozzle; wherein the sum of the first fuel injection amount and the second fuel injection amount is the total amount of fuel injection; control the direct injection nozzle to inject fuel according to the first fuel injection amount, and control the airway injection nozzle to inject fuel according to the second fuel injection amount.

[0214] In one possible implementation, the control module includes a direct injection nozzle control unit, which is specifically used to: when it is determined that the direct injection nozzle performs multiple fuel injections, determine a second target injection amount ratio corresponding to the current temperature of the coolant based on a second preset correspondence; wherein the second preset correspondence is a correspondence between the temperature of the coolant and the injection amount ratio of each injection during multiple fuel injections; the second target injection amount ratio is a ratio between the injection amounts of each injection during multiple fuel injections by the direct injection nozzle; based on the first injection amount and the second target injection amount ratio, determine a single injection amount each time the direct injection nozzle performs fuel injection; and control the direct injection nozzle to inject fuel according to the single injection amount each time fuel injection is performed.

[0215] In one possible implementation, the control module includes a control unit, which is specifically used to: determine a first injection time when the direct injection nozzle performs fuel injection, and determine a second injection time when the airway injection nozzle performs fuel injection; control the direct injection nozzle to inject fuel according to the first injection amount at the first injection time, and control the airway injection nozzle to inject fuel according to the second injection amount at the second injection time.

[0216] In one possible implementation, the control unit includes a first determination unit, which is specifically used to: obtain current operating parameters of the engine; wherein the current operating parameters include current speed and current load; based on a third preset correspondence, determine the target start time for fuel injection of the direct injection nozzle corresponding to the current operating parameters; wherein the third preset correspondence is the correspondence between the operating parameters and the start time for fuel injection of the direct injection nozzle; the operating parameters include speed and load; based on a fourth preset correspondence, determine the target end time for fuel injection of the direct injection nozzle corresponding to the current operating parameters; wherein the fourth preset correspondence is the correspondence between the operating parameters and the end time for fuel injection of the direct injection nozzle; when it is determined that the number of injections when the direct injection nozzle performs fuel injection is multiple times, based on the target start time and the target end time, determine the first injection time of each fuel injection of the direct injection nozzle.

[0217] In one possible implementation, the control unit includes a second determination unit, which is specifically used to: obtain the opening time of the intake valve of the engine, and obtain the injection delay angle when the airway injection nozzle performs fuel injection; wherein the injection delay angle is the crankshaft angle between the start time of the fuel injection of the airway injection nozzle and the opening time of the intake valve; based on the opening time of the intake valve and the injection delay angle, determine the second injection time when the airway injection nozzle performs fuel injection.

[0218] In one possible implementation, the second determination unit includes an acquisition unit, which is specifically used to: acquire the current temperature of the coolant, the intake temperature of the air entering the intake manifold of the engine, and the current speed of the engine; and determine the injection delay angle based on the current temperature of the coolant, the intake temperature, and the current speed of the engine.

[0219] In one possible implementation, the control module is specifically used to: determine a target oil pressure corresponding to the current temperature of the coolant based on the current temperature; control the fuel pump of the engine to adjust the fuel pressure inside the engine; and when it is determined that the fuel pressure inside the engine reaches the target oil pressure, control the direct injection nozzle and the airway injection nozzle to inject fuel according to the first target fuel injection amount ratio to control the cold start of the engine.

[0220] Figure 4 It is a structural schematic diagram of a vehicle provided in an embodiment of the present application.

[0221] For example, Figure 4 As shown, the vehicle 400 includes: a memory 401 and a processor 402, wherein the memory 401 stores an executable program code 4011, and the processor 402 is used to call and execute the executable program code 4011 to perform a cold start method of an engine.

[0222] In addition, an embodiment of the present application also protects a device, which may include a memory and a processor, wherein the memory stores an executable program code, and the processor is used to call and execute the executable program code to execute a cold start method of an engine provided in an embodiment of the present application.

[0223] In this embodiment, the functional modules of the device can be divided according to the above method example. For example, each functional module can be corresponded, or two or more functions can be integrated into one processing module. The above integrated module can be implemented in the form of hardware. It should be noted that the division of modules in this embodiment is schematic and is only a logical function division. There may be other division methods in actual implementation.

[0224] In the case of dividing each functional module according to each function, the device may also include an acquisition module, a determination module, a control module, etc. It should be noted that all relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding functional module, which will not be repeated here.

[0225] It should be understood that the device provided in this embodiment is used to execute the above-mentioned cold start method of the engine, and thus can achieve the same effect as the above-mentioned implementation method.

[0226] In the case of an integrated unit, the device may include a processing module and a storage module. When the device is applied to a vehicle, the processing module may be used to control and manage the actions of the vehicle. The storage module may be used to support the vehicle in executing relevant program codes and data.

[0227] The processing module may be a processor or a controller, which may implement or execute various exemplary logic blocks, modules and circuits shown in conjunction with the disclosure of the present application. The processor may also be a combination that implements computing functions, such as a combination of one or more microprocessors, a combination of digital signal processing (DSP) and a microprocessor, etc. The storage module may be a memory.

[0228] In addition, the device provided in the embodiments of the present application may specifically be a chip, a component or a module, and the chip may include a connected processor and a memory; wherein the memory is used to store instructions, and when the processor calls and executes the instructions, the chip can execute a cold start method of an engine provided in the above embodiments.

[0229] This embodiment also provides a computer-readable storage medium, in which a computer program code is stored. When the computer program code is run on a computer, the computer executes the above-mentioned related method steps to implement a cold start method for an engine provided in the above embodiment.

[0230] This embodiment further provides a computer program product. When the computer program product is run on a computer, the computer is caused to execute the above-mentioned related steps to implement a cold start method of an engine provided in the above embodiment.

[0231] Among them, the device, computer-readable storage medium, computer program product or chip provided in this embodiment is used to execute the corresponding method provided above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding method provided above, and will not be repeated here.

[0232] Through the description of the above implementation methods, technical personnel in the relevant field can understand that for the convenience and simplicity of description, only the division of the above-mentioned functional modules is used as an example. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0233] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0234] The above contents are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A cold start method for an engine, characterized in that: The engine comprises a direct injection nozzle and a port injection nozzle, and the method comprises: Get the current temperature of the coolant in the vehicle's engine; When the current temperature is less than or equal to a preset temperature threshold, obtaining a current speed of the engine, and determining a first target fuel injection amount ratio between fuel injection amounts of a direct injection nozzle and a port injection nozzle of the engine when performing fuel injection based on the current temperature of the coolant and the current speed of the engine; The direct injection nozzle and the airway injection nozzle are controlled to perform fuel injection according to the first target fuel injection amount ratio to control the cold start of the engine.

2. The method according to claim 1, characterized in that The determining, based on the current temperature of the coolant and the current speed of the engine, a first target fuel injection amount ratio between fuel injection amounts of a direct injection nozzle and a port injection nozzle of the engine when performing fuel injection, comprises: Based on a first preset corresponding relationship, a first target fuel injection amount ratio corresponding to the current temperature and the current speed is determined; wherein the first preset corresponding relationship is a corresponding relationship between a target parameter and a target fuel injection amount ratio; the target parameters include the temperature of the coolant and the speed of the engine; the target fuel injection amount ratio is the fuel injection amount ratio when the direct injection nozzle and the airway injection nozzle perform fuel injection.

3. The method according to claim 1, characterized in that The controlling the direct injection nozzle and the airway injection nozzle to perform fuel injection according to the first target fuel injection amount ratio includes: determining a total amount of fuel injection required for a cold start of the engine; Based on the total fuel injection amount and the first target fuel injection amount ratio, determining a first fuel injection amount corresponding to the direct injection nozzle, and determining a second fuel injection amount corresponding to the airway injection nozzle; wherein the sum of the first fuel injection amount and the second fuel injection amount is the total fuel injection amount; The direct injection nozzle is controlled to perform fuel injection according to the first fuel injection amount, and the airway injection nozzle is controlled to perform fuel injection according to the second fuel injection amount.

4. The method according to claim 3, characterized in that: The controlling the direct injection nozzle to perform fuel injection according to the first fuel injection amount includes: When it is determined that the number of times the direct injection nozzle performs fuel injection is multiple times, a second target fuel injection amount ratio corresponding to the current temperature of the coolant is determined based on a second preset corresponding relationship; wherein the second preset corresponding relationship is a corresponding relationship between the temperature of the coolant and the fuel injection amount ratio of each injection during multiple fuel injections; and the second target fuel injection amount ratio is a ratio between the fuel injection amounts of each injection during multiple fuel injections by the direct injection nozzle; determining a single fuel injection amount when the direct injection nozzle performs fuel injection each time based on the ratio of the first fuel injection amount to the second target fuel injection amount; The direct injection nozzle is controlled to perform fuel injection according to the single fuel injection amount each time fuel injection is performed.

5. The method according to claim 3, characterized in that: The controlling the direct injection nozzle to perform fuel injection according to the first fuel injection amount, and controlling the airway injection nozzle to perform fuel injection according to the second fuel injection amount, comprises: Determining a first injection time when the direct injection nozzle performs fuel injection, and determining a second injection time when the airway injection nozzle performs fuel injection; The direct injection nozzle is controlled to perform fuel injection according to the first injection amount at the first injection time, and the airway injection nozzle is controlled to perform fuel injection according to the second injection amount at the second injection time.

6. The method according to claim 5, characterized in that The step of determining a first injection timing when the direct injection nozzle performs fuel injection comprises: Acquire current operating parameters of the engine; wherein the current operating parameters include current speed and current load; Based on a third preset corresponding relationship, determining a target start time for the direct injection nozzle to perform fuel injection corresponding to the current operating parameter; wherein the third preset corresponding relationship is a corresponding relationship between the operating parameter and the start time for the direct injection nozzle to perform fuel injection; the operating parameter includes a rotation speed and a load; Based on a fourth preset corresponding relationship, determining a target end time of the fuel injection by the direct injection nozzle corresponding to the current operating parameter; wherein the fourth preset corresponding relationship is a corresponding relationship between the operating parameter and the end time of the fuel injection by the direct injection nozzle; When it is determined that the number of injections when the direct injection nozzle performs fuel injection is multiple times, the first injection time each time the direct injection nozzle performs fuel injection is determined based on the target start time and the target end time.

7. The method according to claim 5, characterized in that The step of determining a second injection timing when the airway injection nozzle performs fuel injection comprises: Obtaining the opening time of the intake valve of the engine, and obtaining the injection delay angle when the airway injection nozzle performs fuel injection; wherein the injection delay angle is the crankshaft angle between the start time of the fuel injection by the airway injection nozzle and the opening time of the intake valve; Based on the opening timing of the intake valve and the injection delay angle, a second injection timing when the port injection nozzle performs fuel injection is determined.

8. The method according to claim 7, characterized in that The step of obtaining the injection delay angle when the airway injection nozzle performs fuel injection comprises: Acquiring the current temperature of the coolant, the intake temperature of the air entering the intake manifold of the engine, and the current speed of the engine; The injection delay angle is determined based on the current temperature of the coolant, the intake air temperature, and the current speed of the engine.

9. The method according to claim 1, characterized in that: The controlling the direct injection nozzle and the airway injection nozzle to perform fuel injection according to the first target fuel injection amount ratio to control the cold start of the engine includes: Based on the current temperature of the coolant, determining a target oil pressure corresponding to the current temperature; Controlling a fuel pump of the engine to adjust the fuel pressure inside the engine; When it is determined that the fuel pressure inside the engine reaches the target oil pressure, the direct injection nozzle and the airway injection nozzle are controlled to perform fuel injection according to the first target injection amount ratio to control the cold start of the engine.

10. A vehicle, characterized in that: The vehicle comprises: A memory for storing executable program codes; A processor, configured to call and run the executable program code from the memory so that the vehicle executes the method according to any one of claims 1 to 9.

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