Vehicle and fuel gas injection control method and device of fuel gas injection system of vehicle

Abstract

The invention discloses a vehicle and a fuel gas injection control method and device of a fuel gas injection system of the vehicle. The control method comprises the steps that the operation working condition of the vehicle gas injection system is obtained in real time; the operation working conditions at least comprise the operation state and the rotating speed of the engine, the temperature of engine cooling liquid, the gas inlet pressure and the gas inlet temperature at the inlet of the gas inlet pipeline, and the gas pressure and the gas temperature at the inlet of the gas ejector; the mass of pre-injected fuel gas is determined according to the current operation working condition of the vehicle fuel gas injection system; the opening degree and the opening time of a gas injector are determined, and the gas injector is controlled to conduct gas pre-injection according to the opening degree and the opening time; after fuel gas pre-injection is finished, according to the current operation working condition, the reinjection fuel gas quality is determined; and the opening degree of the fuel gas injector is determined, and the fuel gas injector is controlled to conduct fuel gas supplementary injection according to the opening degree until it is determined that the current operation state is in the timing synchronization state. The starting speed and the starting stability of the engine are improved.

Description

Technical Field

[0001] This invention relates to the field of natural gas engine technology, and in particular to a gas injection control method and device for a vehicle and its gas injection system. Background Technology

[0002] With the increasing demands for energy conservation and emission reduction in commercial vehicle powertrains, natural gas engines have seen a gradual increase in their application in the commercial vehicle sector in recent years due to their better fuel economy, lower emissions, and superior thermal management performance.

[0003] In existing technologies, commercial vehicle natural gas engines mostly adopt a single-point injection gas supply method. The gas is injected into a mixer located at the intake manifold through a gas injector, where it is mixed with fresh air and recirculated exhaust gas. After that, it is delivered to each cylinder through the intake manifold and intake pipe, where it is ignited and burned by spark plugs.

[0004] However, there is usually an intake passage of a certain length and volume between the mixer and the intake manifold, and the specific layout of this passage is also affected by the engine structural design. Therefore, there is a certain transmission process and time delay between the injection of gas into the mixer and the entry of the mixture into the cylinder. This makes the engine start-up time longer than that of direct injection gasoline or diesel engines of similar displacement, especially in cold start conditions in winter. This not only increases the continuous dragging time of the starter motor and accelerates battery depletion, but also increases the risk of spark plug freezing in low-temperature conditions, thus affecting engine starting stability and the user's driving experience. Summary of the Invention

[0005] This invention provides a gas injection control method and device for a vehicle and its gas injection system. Based on the operating conditions of the vehicle's gas injection system, the method dynamically adjusts the pre-injection gas quality and supplementary injection gas quality of the gas injector, thereby improving the engine's starting speed and starting smoothness.

[0006] The first aspect of the present invention provides a gas injection control method for a vehicle gas injection system, the vehicle gas injection system including at least an engine, a mixer, an intake pipe, and a gas injector, the engine including a plurality of cylinders, the mixer being connected to each of the cylinders through the intake pipe, and the gas injector being used to inject natural gas into the mixer; The gas injection control method for the vehicle gas injection system includes: The operating conditions of the vehicle's gas injection system are acquired in real time; the operating conditions include at least the engine's operating status and speed, the engine coolant temperature, the intake pressure and intake temperature at the intake manifold inlet, and the gas pressure and gas temperature at the gas injector inlet. Determine the pre-injected gas quality based on the current operating conditions of the vehicle's gas injection system; Based on the current operating conditions and the quality of the pre-injected gas, determine the opening degree and opening time of the gas injector, and control the gas injector to pre-inject gas according to the opening degree and opening time; After the pre-injection of gas is completed, the quality of supplementary gas injection is determined based on the current operating conditions. Based on the current operating conditions and the quality of the supplementary gas, the opening degree of the gas injector is determined, and the gas injector is controlled to perform supplementary gas injection according to the opening degree until it is determined that the current operating state is in a timing synchronization state.

[0007] Optionally, before determining the pre-injected fuel quality based on the current operating conditions of the vehicle's fuel injection system, the method further includes: Determine whether the current operating condition meets the first preset condition; if so, determine the pre-injected gas quality based on the current operating condition. The first preset condition includes the duration for which the current engine speed is zero is greater than a first preset time threshold, and the current operating state of the engine is not in the fuel cut-off scavenging state.

[0008] Optionally, the pre-injected fuel quality is determined based on the current operating conditions of the vehicle's fuel injection system, including: Obtain the engine's displacement and equivalent air-fuel ratio; The current air mass in the intake pipe is determined based on the engine displacement, the current intake pressure at the intake pipe inlet, and the current intake temperature. Based on the current air quality and the equivalent air-fuel ratio, determine the current required gas mass; The pre-injection gas mass is determined based on the current temperature of the engine coolant and the current required gas mass.

[0009] Optionally, the degree of opening and the opening time of the gas injector are determined based on the current operating conditions and the pre-injected gas quality, including: The degree of opening and the opening time of the gas injector are determined based on the current gas pressure and temperature at the gas injector inlet and the pre-injected gas quality.

[0010] Optionally, before determining the quality of the supplementary fuel injection based on the current operating conditions, the method further includes: Determine whether the current operating condition meets the second preset condition; if so, determine the quality of the supplementary gas injection based on the current operating condition. The second preset condition includes the engine's current speed being non-zero, the engine's current operating state not being in the fuel cut-off scavenging state, and the duration of the engine's current operating state being in the non-timing synchronization state being less than the second preset time threshold.

[0011] Optionally, the quality of the supplementary fuel gas is determined based on the current operating conditions, including: Obtain the displacement of the engine; The required fuel mass is determined based on the engine displacement and current speed, the current intake pressure at the intake manifold inlet, and the current intake temperature. The mass of supplementary fuel gas is determined based on the current rotational speed, the current intake pressure, and the current required fuel gas mass.

[0012] Optionally, the degree of opening of the gas injector is determined based on the current operating conditions and the quality of the supplementary gas injection, including: The degree of opening of the gas injector is determined based on the current gas pressure and temperature at the inlet of the gas injector, as well as the quality of the supplementary gas.

[0013] Optionally, the gas injection control method for the vehicle gas injection system further includes: After the gas pre-injection ends, it is determined whether the current operating condition meets the third preset condition; if so, the injection mode of the gas injector is adjusted to quasi-continuous flow injection until it is determined that the current operating condition meets the fourth preset condition, and then the injection mode of the gas injector is adjusted to pulse injection. The third preset condition includes the engine's current speed being non-zero, the engine's current operating state not being in the fuel cut-off scavenging state, the current gas temperature at the gas injector inlet being lower than a preset temperature threshold, and the duration for which the engine's current speed is lower than a preset speed threshold being less than a third preset time threshold. The fourth preset condition includes the current rotational speed being greater than or equal to the preset rotational speed threshold, or the duration during which the current rotational speed is less than the preset rotational speed threshold being greater than or equal to the third preset time threshold.

[0014] A second aspect of the present invention provides a gas injection control device for a vehicle gas injection system, the vehicle gas injection system including at least an engine, a mixer, an intake pipe, and a gas injector, the engine including a plurality of cylinders, the mixer being connected to each of the cylinders through the intake pipe, and the gas injector being used to inject natural gas into the mixer; The gas injection control device of the vehicle gas injection system includes: The operating condition acquisition module is used to acquire the operating condition of the vehicle's gas injection system in real time; the operating condition includes at least the engine's operating status and speed, the engine coolant temperature, the intake pressure and intake temperature at the intake manifold inlet, and the gas pressure and gas temperature at the gas injector inlet. The pre-injection gas quality determination module is used to determine the pre-injection gas quality based on the current operating conditions of the vehicle's gas injection system. The gas pre-injection control module is used to determine the opening degree and opening time of the gas injector based on the current operating conditions and the quality of the pre-injected gas, and to control the gas injector to perform gas pre-injection according to the opening degree and the opening time. The supplementary gas injection quality determination module is used to determine the quality of supplementary gas injection based on the current operating conditions after the gas pre-injection is completed. The gas supplementary injection control module is used to determine the opening degree of the gas injector based on the current operating conditions and the quality of the supplementary gas, and control the gas injector to perform supplementary gas injection according to the opening degree until it is determined that the current operating state is in a timing synchronization state.

[0015] A third aspect of the present invention provides a vehicle, the vehicle comprising: a frame, a vehicle fuel injection system disposed within the frame, and a controller; The vehicle gas injection system includes at least an engine, a mixer, an intake pipe, and a gas injector. The engine includes multiple cylinders, the mixer is connected to each of the cylinders through the intake pipe, and the gas injector is used to inject natural gas into the mixer. The controller is connected to the vehicle's fuel injection system and is used to execute the fuel injection control method of the vehicle's fuel injection system as described above.

[0016] The technical solution of this invention, by acquiring the real-time operating conditions of the vehicle's fuel injection system, can determine the pre-injected fuel quality based on the current operating conditions of the fuel injection system. This allows for the determination of the injector's opening degree and timing based on the current operating conditions and the pre-injected fuel quality, and controls the injector to perform pre-injection according to the opening degree and timing. This helps shorten the time interval between the starter motor pulling the fuel into the cylinder to form a combustible mixture, improving the engine's starting speed. Furthermore, after the pre-injection ends, the quality of the supplementary fuel injection is determined based on the current operating conditions. This allows for the determination of the injector's opening degree based on the current operating conditions and the supplementary fuel injection quality, and controls the injector to perform supplementary fuel injection according to the opening degree until the current operating state is determined to be in a synchronized timing state. This helps reduce the combustion discontinuity problem caused by an excessively lean mixture between the end of pre-injection and the establishment of synchronized injection, improving the smoothness and stability of the engine starting process.

[0017] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic flowchart of a gas injection control method for a vehicle gas injection system provided in Embodiment 1 of the present invention; Figure 2 This is a schematic flowchart of a gas injection control method for a vehicle gas injection system provided in Embodiment 2 of the present invention; Figure 3 This is a flowchart illustrating a gas injection control method for a vehicle gas injection system according to Embodiment 3 of the present invention; Figure 4 This is a schematic flowchart of a gas injection control method for a vehicle gas injection system provided in Embodiment 4 of the present invention; Figure 5 This is a schematic diagram of the structure of a gas injection control device for a vehicle gas injection system provided in Embodiment 5 of the present invention. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0022] Example 1 Figure 1 This is a flowchart illustrating a gas injection control method for a vehicle gas injection system according to Embodiment 1 of the present invention. This embodiment can be used to dynamically adjust the pre-injection gas quality and supplementary injection gas quality of the gas injector. This method can be executed by the gas injection control device of the vehicle gas injection system. This device can be implemented by software and / or hardware, and is generally integrated into the vehicle's controller. Accordingly, as... Figure 1 As shown, the gas injection control method of the vehicle's gas injection system may include: S101. Real-time acquisition of the operating status of the vehicle's fuel injection system.

[0023] The operating conditions include at least the engine's operating status and speed, the engine coolant temperature, the intake pressure and temperature at the intake manifold inlet, and the gas pressure and temperature at the gas injector inlet.

[0024] It should be noted that a vehicle's gas injection system includes at least an engine, a mixer, an intake manifold, and gas injectors. The engine comprises multiple cylinders, and the mixer is connected to each cylinder via the intake manifold, allowing the air-fuel mixture formed in the mixer to be delivered to the corresponding cylinder. The gas injectors inject natural gas into the mixer, mixing it with the incoming fresh air, which is then drawn into each cylinder and burned to produce power.

[0025] Specifically, to dynamically adjust the pre-injection and supplementary injection quality of the gas injector, the operating conditions of the vehicle's gas injection system can be acquired in real time. The engine's operating status can be used to characterize the engine's current operating stage, such as whether the engine is stationary, starting, in a fuel cut-off scavenging state, out-of-timing state, or in a timing-synchronized state; engine speed characterizes the engine's current rotational state; engine coolant temperature characterizes the engine's overall thermal state; intake pressure and temperature at the intake manifold inlet characterize the air-side state entering the mixer and intake manifold, reflecting the current air density and quality entering the intake manifold; and gas pressure and temperature at the gas injector inlet characterize the natural gas supply state before entering the gas injector, with gas pressure affecting the injection flow rate and gas temperature affecting the natural gas's state parameters and the gas injector's operating state under low-temperature conditions.

[0026] S102. Determine the quality of pre-injected gas based on the current operating conditions of the vehicle's gas injection system.

[0027] Understandably, before the engine officially enters the starting and combustion phase, the controller can pre-calculate the amount of natural gas to be injected into the mixer based on the current operating conditions. This ensures that when the engine starts rotating with the starter, the mixer and intake manifold already have a suitable mixture for being drawn into the cylinder and participating in combustion. If natural gas injection begins after the starter has started the engine, the natural gas needs to be injected, mixed, and delivered while the engine is already running, which can lead to a delay in the formation of the combustible mixture entering the cylinder, thus prolonging the engine starting time. Therefore, pre-determining and injecting an appropriate amount of natural gas before starting the engine helps to shorten the time interval between the starter pulling the gas into the cylinder to form a combustible mixture, reducing the impact of gas supply delay on the engine starting response.

[0028] Specifically, the controller can estimate the air quality in the intake manifold based on the current operating conditions of the vehicle's fuel injection system, and further determine the fuel quality that matches the air quality, so that the ratio of air to natural gas in the pre-injected mixer is within a range suitable for ignition and combustion, thereby improving engine start-up speed and start-up smoothness.

[0029] S103. Based on the current operating conditions and the quality of the pre-injected gas, determine the opening degree and opening time of the gas injector, and control the gas injector to pre-inject gas according to the opening degree and opening time.

[0030] Specifically, after determining the pre-injected gas quality, the controller can further determine the opening mode of the gas injector based on the current operating conditions, so as to determine the opening degree and opening time required for the gas injector to achieve the target pre-injected gas quality. The opening degree characterizes the size of the gas injector valve opening, and the opening time characterizes the duration the gas injector remains open; both together determine the total amount of natural gas injected into the mixer during the gas pre-injection process.

[0031] Once the controller determines the opening degree and duration of the gas injector, it can output a corresponding control signal to the gas injector to control it to pre-inject gas according to the determined opening degree and duration. This ensures that the actual injection action of the gas injector matches the pre-injection control requirements, thus guaranteeing the rapid formation of a suitable air-fuel mixture for ignition and combustion during subsequent engine start-up.

[0032] S104. After the pre-injection of gas is completed, determine the quality of the supplementary gas injection based on the current operating conditions.

[0033] It is understandable that engine operating states include synchronized and unsynchronized states. Unsynchronized state refers to a state where, although the engine has started to rotate under the starter motor's influence, the controller has not yet completed timing synchronization determination based on crankshaft position signals and / or camshaft position signals. Therefore, it cannot yet implement normal injection control according to the accurate intake, compression, and ignition timing sequence of each cylinder. Synchronized state refers to a state where the controller has completed timing synchronization determination, can identify the engine's current phase relationship, and implements injection and ignition control according to the predetermined timing sequence. Before the engine switches from unsynchronized to synchronized state, there is usually a brief transition window. During this window, if only the pre-injection mixture formed before starting is relied upon, as the engine continues to rotate, some of the pre-injected gas will be drawn into the cylinder and participate in combustion. However, the new synchronized injection has not yet been established, which can easily lead to the air-fuel ratio of the remaining mixture in the mixer and intake manifold gradually becoming lean and unable to be reliably ignited. This results in problems such as delayed engine start-up response, discontinuous combustion, or an unsmooth start-up process.

[0034] Therefore, after the pre-injection of gas ends, the controller can further determine the quality of the supplementary gas injection based on the current operating conditions, thereby providing a basis for the subsequent control of the gas injector to implement supplementary injection, so as to continue to supplement a certain amount of natural gas into the mixer during the above-mentioned non-synchronization phase, so that the air-to-gas ratio in the mixer and subsequently entering the cylinder is maintained within a relatively suitable range.

[0035] S105. Based on the current operating conditions and the quality of the supplementary gas, determine the opening degree of the gas injector, and control the gas injector to perform supplementary gas injection according to the opening degree until it is determined that the current operating state is in a timed synchronization state.

[0036] Specifically, after determining the quality of the supplementary gas injection, the controller can further determine the opening degree of the gas injector based on the current operating conditions and the quality of the supplementary gas injection. This allows the gas injector to convert the quality of the supplementary gas injection into control parameters that can be executed by the gas injector, so that the gas injector can continuously supplement natural gas into the mixer during the off-time synchronization phase of the engine start-up process.

[0037] After determining the opening degree of the gas injector, the controller can output a control signal to the gas injector to control it to perform supplementary gas injection according to the determined opening degree. Supplementary gas injection can continue until the controller determines that the engine's current operating state is in a timing synchronization state. It can be understood that when the controller determines that the engine's current operating state is in a timing synchronization state, it indicates that the engine is ready to be controlled according to the normal injection sequence. At this point, the supplementary gas injection process can be terminated, and the system can switch to the subsequent normal injection control mode. Therefore, the duration of supplementary injection control is limited to the time window during the engine's transition from the pre-injection stage to the synchronous injection stage. This ensures the continuity of gas supply during the transition stage while avoiding an overly rich mixture caused by continuing supplementary injection after entering normal synchronous control.

[0038] By dynamically adjusting the quality of pre-injected gas and supplementary injection gas from the gas injector, coordinated control of pre-injection before engine start and supplementary injection during start-up can be achieved. This can shorten the time between the engine being driven by the starter motor and the formation of an ignitable mixture and the establishment of stable combustion, thereby improving the engine's start-up speed. At the same time, it can reduce the combustion discontinuity problem caused by an excessively lean mixture between the end of pre-injection and the establishment of synchronous injection, thus improving the smoothness and stability of the engine start-up process.

[0039] In this embodiment, by acquiring the real-time operating conditions of the vehicle's fuel injection system, the pre-injection fuel quality can be determined based on the current operating conditions. This allows for the determination of the injector's opening degree and timing, and control of the injector to perform pre-injection according to the specified opening degree and timing. This helps shorten the time interval between the starter motor pulling the fuel into the cylinder to form a combustible mixture, improving engine starting speed. Furthermore, after pre-injection, the quality of supplementary fuel injection is determined based on the current operating conditions. This allows for the determination of the injector's opening degree, and control of the injector to perform supplementary fuel injection according to the specified opening degree, until the current operating state is determined to be in a synchronized timing state. This helps reduce the combustion discontinuity problem caused by an excessively lean mixture between the end of pre-injection and the establishment of synchronized injection, improving the smoothness and stability of the engine starting process.

[0040] Example 2 Figure 2 This is a flowchart illustrating a gas injection control method for a vehicle gas injection system according to Embodiment 2 of the present invention. Based on the above embodiments, this embodiment provides a detailed explanation of the method for determining the pre-injected gas quality according to the current operating conditions of the vehicle gas injection system, and for determining the opening degree and opening time of the gas injector according to the current operating conditions and the pre-injected gas quality. Figure 2 As shown, the fuel injection control method of the vehicle fuel injection system in this embodiment may include: S201. Real-time acquisition of the operating status of the vehicle's fuel injection system.

[0041] The operating conditions include at least the engine's operating status and speed, the engine coolant temperature, the intake pressure and temperature at the intake manifold inlet, and the gas pressure and temperature at the gas injector inlet.

[0042] Optionally, before determining the pre-injected gas quality based on the current operating conditions of the vehicle's gas injection system, the method further includes: determining whether the current operating conditions meet a first preset condition; if so, determining the pre-injected gas quality based on the current operating conditions; wherein the first preset condition includes the duration for which the engine's current speed is zero being greater than a first preset time threshold, and the engine's current operating state not being in a fuel cut-off scavenging state.

[0043] Specifically, before determining the pre-injection fuel quality based on the current operating conditions of the vehicle's fuel injection system, the controller can first determine whether the current operating conditions meet the pre-injection conditions. This avoids erroneous pre-injection under unsuitable conditions, thereby improving the accuracy and safety of pre-start injection control. When the engine controller (Electronic Control Unit, ECU) is powered on, the controller first reads whether the ECU is in its first operating state after being rewritten. The first operating state after the ECU is rewritten is used to characterize the first working cycle after the control program or calibration parameters are updated. When the ECU is in its first operating state after being rewritten, its control parameters, state variables, and related adaptation logic may be in the stage of re-establishment or re-initialization. If pre-start injection is executed immediately at this time, it may increase control uncertainty. Therefore, after the controller determines that the ECU is not in its first operating state after being rewritten, it further counts the duration of the engine speed being zero and reads the pre-start injection status flag and the status flag indicating whether the engine is in the fuel cut-off scavenging state stored in the ECU's electrically erasable programmable read-only memory (EEPROM).

[0044] The pre-start injection status flag indicates whether pre-start injection has been completed in the current driving cycle. The EEPROM retains this status information after a power outage, allowing for continued reading and judgment upon the next power-on. If the controller determines that pre-start injection is incomplete, it can further determine whether the current operating condition meets a first preset condition. The first preset condition includes at least that the engine's current speed is zero for a duration greater than a first preset time threshold, and that the engine's current operating state is not in a fuel cut-off scavenging state. It can be understood that a duration of zero engine speed greater than the first preset time threshold indicates that the engine's current operating state is a stable, ready-to-start condition, rather than a transient fluctuation phase or a short-term speed change phase immediately after engine shutdown. The fuel cut-off scavenging state refers to the control state where, after the engine has failed to start normally for an extended period or has failed to start, the controller temporarily stops the air supply and scavenges the intake passage and cylinders through airflow to avoid a continuously rich air-fuel mixture and improve the success rate of subsequent starts. By determining whether the current operating condition meets the first preset condition, erroneous pre-injection control can be avoided during unstable operating conditions or abnormal start recovery phases.

[0045] Furthermore, when the engine's current speed is non-zero, the controller can also count the duration of this non-zero speed. If the duration exceeds a corresponding threshold, it indicates that the engine has completed the starting or rotation process in the current driving cycle. At this time, when the vehicle key switch is detected to be off, the controller can set the pre-start injection status to "incomplete" and write this status into the ECU's EEPROM, so that the vehicle's fuel injection system can resume pre-start injection control the next time it is powered on and the corresponding conditions are met.

[0046] S202, Obtain the engine displacement and stoichiometric air-fuel ratio.

[0047] Specifically, after determining that the current operating conditions meet the first preset condition, it indicates that the vehicle's fuel injection system has the basic conditions to execute pre-start fuel injection control. At this point, the controller can further determine the quality of the pre-injected fuel. In order to accurately determine the quality of the pre-injected fuel that matches the current intake state, the controller can first obtain the engine displacement and stoichiometric air-fuel ratio.

[0048] Among them, the engine displacement can be used to characterize the engine's basic intake capacity in terms of structure. The larger the engine displacement, the larger the total amount of gas that can be drawn in per unit working cycle. The equivalence air-fuel ratio can be used to characterize the ratio of natural gas to air under suitable combustion conditions. By obtaining the engine displacement and equivalence air-fuel ratio, a data basis is provided for subsequent calculation of the pre-injected gas quality.

[0049] S203. Determine the current air quality in the intake manifold based on the engine displacement, the current intake pressure at the intake manifold inlet, and the current intake temperature.

[0050] Understandably, before the pre-injection, a certain amount of fresh air usually already exists in the mixer and its subsequent connected intake pipes. In order to ensure that the natural gas injected later forms a suitable mixing ratio with this portion of air, the controller can first determine the current mass of this portion of air.

[0051] Specifically, the intake duct between the mixer and the intake manifold inlet has a certain channel volume, which is usually related to the engine displacement. Furthermore, the actual mass of air in the intake duct is related not only to the volume but also to the current air state parameters. Therefore, the controller can calculate the mass of fresh air filling the intake duct between the mixer and the intake manifold inlet by combining the engine displacement, current intake pressure, and current intake temperature, thus obtaining the current air mass in the intake duct.

[0052] For example, a mapping relationship between engine displacement, intake pressure, intake temperature, and air mass in the intake manifold can be pre-established and stored in the controller. This allows the controller to obtain the corresponding current air mass by directly looking up a table or converting data based on the pre-defined mapping relationship after acquiring the engine displacement, current intake pressure, and current intake temperature. The mapping relationship can be determined based on experimental test results, and this invention does not impose specific limitations on it.

[0053] S204. Determine the required gas mass based on the current air quality and equivalent air-fuel ratio.

[0054] Specifically, the stoichiometric air-fuel ratio (SFR) characterizes the ratio of air to natural gas under suitable combustion conditions. Therefore, given a fixed air quality, the controller can convert the current air quality into the corresponding required gas mass based on the SFR. This allows for the determination of a target gas mass that matches the current air conditions, ensuring that the natural gas pre-injected into the mixer can form a more reasonable mixing ratio with the existing air in the intake channel.

[0055] S205. Determine the pre-injection gas quality based on the current temperature of the engine coolant and the current required gas quality.

[0056] Specifically, given a fixed required fuel mass, a fuel enrichment coefficient can be further determined based on the current engine coolant temperature to reflect the adjustment requirements for pre-injected fuel volume under different thermal conditions. For example, the controller can determine the fuel enrichment coefficient corresponding to the current engine coolant temperature based on a preset mapping relationship, and multiply this coefficient by the required fuel mass to obtain the final required fuel mass, i.e., the pre-injected fuel mass. When the engine coolant temperature is low, the corresponding fuel enrichment coefficient can be relatively large to appropriately increase the pre-injected fuel mass; when the engine coolant temperature is high, the corresponding fuel enrichment coefficient can be relatively small to avoid excessive pre-injection. In this way, the pre-injected fuel mass can be adaptively corrected based on the basic fuel demand and the actual hot / cold state of the engine.

[0057] S206. Based on the current gas pressure and temperature at the gas injector inlet and the quality of the pre-injected gas, determine the opening degree and opening time of the gas injector, and control the gas injector to pre-inject gas according to the opening degree and opening time.

[0058] Specifically, after determining the pre-injected gas quality, the controller can calculate the corresponding opening degree and opening time of the gas injector based on the current gas pressure, current gas temperature, and pre-injected gas quality. The opening degree of the gas injector characterizes the gas injection flow rate, and the opening time characterizes the duration the gas injector remains open. The opening time determines the quality of gas injected at the corresponding gas injection flow rate.

[0059] After determining the opening degree and timing of the gas injector, the controller can output corresponding control signals to the gas injector to control it to perform gas pre-injection according to the determined opening degree and timing. This ensures that the actual injection action of the gas injector matches the pre-injection control requirements, so that the air-to-natural gas ratio in the pre-injected mixture is within a range suitable for ignition and combustion, thereby improving engine start-up speed and start-up smoothness.

[0060] Furthermore, after the pre-injection of fuel gas is completed, the controller can set the pre-injection status to "completed" and store it in the ECU's EEPROM when the vehicle key switch is detected as off. This allows the controller to read the pre-injection status stored in the EEPROM when the vehicle is subsequently powered on again, and prevent the pre-injection control operation from being executed again until the status is reset. This avoids the ECU repeatedly executing pre-injection during repeated power-on and power-off cycles, preventing the continuous accumulation of natural gas in the mixer and intake manifold. It is understandable that if the air-fuel mixture in the mixer and intake manifold is too rich, the mixture entering the cylinders may be difficult to ignite reliably, and unburned natural gas may enter the aftertreatment system with the exhaust, causing abnormal heating or even high-temperature erosion of the aftertreatment system. By writing the pre-injection completion status into the EEPROM after pre-injection and reading and judging this status upon subsequent power-on, the risks of an overly rich mixture and damage to the aftertreatment system caused by repeated pre-injection can be effectively avoided, thereby improving the safety and reliability of pre-injection control.

[0061] S207. After the pre-injection of gas is completed, determine the quality of the supplementary gas injection based on the current operating conditions.

[0062] S208. Based on the current operating conditions and the quality of the supplementary gas injection, determine the opening degree of the gas injector and control the gas injector to perform supplementary gas injection according to the opening degree until it is determined that the current operating state is in a timing synchronization state.

[0063] In this embodiment, by acquiring the engine displacement and equivalent air-fuel ratio, the current air quality in the intake manifold can be determined based on the engine displacement, the current intake pressure at the intake manifold inlet, and the current intake temperature. Furthermore, the required fuel gas quality can be determined based on the current air quality and equivalent air-fuel ratio. By determining the pre-injection fuel gas quality based on the current engine coolant temperature and the required fuel gas quality, the pre-injection fuel gas quality can be adaptively corrected based on the basic fuel gas demand and the actual hot / cold state of the engine. By determining the opening degree and opening time of the fuel injector based on the current fuel pressure and temperature at the fuel injector inlet and the pre-injection fuel quality, and controlling the fuel injector to pre-inject fuel gas according to the opening degree and opening time, the actual injection action of the fuel injector can be matched with the pre-injection control requirements. This ensures that the air-to-natural gas ratio in the pre-injected mixture is within a range suitable for ignition and combustion, thereby improving engine start-up speed and start-up smoothness.

[0064] Example 3 Figure 3 This is a flowchart illustrating a gas injection control method for a vehicle gas injection system according to Embodiment 3 of the present invention. Based on the above embodiments, this embodiment provides a detailed explanation of the method for determining the quality of supplementary gas injection based on the current operating conditions, and for determining the opening degree of the gas injector based on the current operating conditions and the quality of supplementary gas injection. Figure 3 As shown, the fuel injection control method of the vehicle fuel injection system in this embodiment may include: S301. Real-time acquisition of the operating status of the vehicle's fuel injection system.

[0065] The operating conditions include at least the engine's operating status and speed, the engine coolant temperature, the intake pressure and temperature at the intake manifold inlet, and the gas pressure and temperature at the gas injector inlet.

[0066] S302. Determine the pre-injected gas quality based on the current operating conditions of the vehicle's gas injection system.

[0067] S303. Based on the current operating conditions and the quality of the pre-injected gas, determine the opening degree and opening time of the gas injector, and control the gas injector to pre-inject gas according to the opening degree and opening time.

[0068] Optionally, before determining the quality of the supplementary fuel injection based on the current operating conditions, the method further includes: determining whether the current operating conditions meet the second preset condition; if so, determining the quality of the supplementary fuel injection based on the current operating conditions; wherein the second preset condition includes the engine's current speed being non-zero, the engine's current operating state not being in the fuel cut-off scavenging state, and the duration of the engine's current operating state being in the non-timing synchronization state being less than the second preset time threshold.

[0069] Specifically, before determining the quality of supplementary fuel injection based on the current operating conditions, the controller can first determine whether the current operating conditions meet the second preset condition, so as to confirm whether the current engine is in a suitable time window for asynchronous supplementary fuel injection, thereby avoiding additional fuel injection at inappropriate stages and affecting the stability of the subsequent start-up process.

[0070] After confirming that the ECU has not been flashed and after verifying that the engine has been stably stationary for a period of time before the start-up, the controller determines whether the current operating condition meets the second preset condition. The second preset condition includes at least the following: the engine's current speed is not zero; the engine's current operating state is not in the fuel cut-off scavenging state; and the duration of the engine's current operating state in the non-timing synchronization state is less than the second preset time threshold. Specifically, a non-zero engine speed indicates that the engine has started to rotate under the starter motor's influence. At this time, the air-fuel mixture formed by the pre-start injection has begun to be drawn into the engine and gradually consumed, thus providing a basis for further injection control. The engine's current operating state is not in the fuel cut-off scavenging state, indicating that the engine is not currently in the stage of expelling residual overly rich mixture by stopping air supply, but is still in the stage where supplementary combustion gas is allowed to establish a combustible mixture. The duration of the engine's current operating state in the non-timing synchronization state is less than the second preset time threshold, indicating that the engine is still within the brief window of transition from the pre-start injection stage to the normal synchronous injection stage. At this time, injection control can compensate for the gradually consumed pre-injected combustion gas.

[0071] Furthermore, the controller can disable supplementary injection when any of the enabling conditions for supplementary injection control are no longer met. It is understandable that if the duration of the non-timing synchronization state exceeds the corresponding threshold, it indicates that the engine has not completed timing synchronization for an extended period. Continued supplementary injection may cause gas accumulation, affecting subsequent combustion establishment. If the engine has already entered timing synchronization but non-synchronous supplementary injection does not stop in time, the non-synchronous injection gas may overlap with the synchronous injection gas, resulting in an overly rich mixture in the mixer that is difficult to ignite. If the engine has already entered the fuel cut-off scavenging state and supplementary injection continues, it will also interfere with the fuel cut-off scavenging process. All of the above situations may cause abnormal heating or even high-temperature erosion of the aftertreatment system, or cause the engine to fail to start after prolonged dragging, thus adversely affecting the reliability of the vehicle's aftertreatment components and the overall starting system.

[0072] S304, Obtain the engine displacement.

[0073] Specifically, after determining that the current operating conditions meet the second preset condition, it indicates that the vehicle's fuel injection system has the basic conditions to perform supplementary fuel injection control within a short window during the transition from the pre-injection phase to the normal synchronous injection phase. At this point, the controller can further determine the quality of the supplementary fuel injection. To accurately determine the quality of the supplementary fuel injection that matches the current operating conditions, the controller can first obtain the engine displacement.

[0074] S305. Determine the required fuel mass based on the engine displacement and current speed, the current intake pressure at the intake manifold inlet, and the current intake temperature.

[0075] Specifically, the controller can determine the equivalent fuel demand during the asynchronous supplemental injection phase based on the engine displacement and current speed, as well as the current intake pressure and temperature at the intake manifold inlet. For example, a mapping relationship between engine displacement, engine speed, intake pressure, intake temperature, and equivalent fuel demand can be pre-established and stored in the controller. During actual control, the controller can look up or convert the parameters to obtain the required fuel mass. This mapping relationship can be determined based on experimental calibration results, empirical models, or practical application experience; this invention does not impose specific limitations on it.

[0076] S306. Determine the quality of supplementary fuel injection based on the current engine speed, current intake pressure, and current required fuel gas quality.

[0077] Specifically, after determining the basic gas demand during the asynchronous injection phase, the controller can further determine the fuel enrichment coefficient by combining the current engine speed and current intake pressure. This enrichment coefficient is then multiplied by the required gas mass to obtain the supplementary injection gas mass. This allows for compensation and correction of the required gas mass based on the current operating conditions, improving the real-time performance and accuracy of determining the supplementary injection gas mass. Determining the supplementary injection gas mass provides a data foundation for subsequent control of the gas injectors, facilitating timely replenishment of appropriate amounts of natural gas during the transition window before startup, when pre-injected gas is gradually consumed and synchronous injection has not yet been established. This maintains the air-fuel ratio in the mixer and intake manifold within a suitable range, thereby improving engine start-up speed and smoothness.

[0078] S307. Based on the current gas pressure and temperature at the gas injector inlet and the quality of the supplementary gas, determine the opening degree of the gas injector and control the gas injector to perform supplementary gas injection according to the opening degree until it is determined that the current operating state is in the timing synchronization state.

[0079] Specifically, after determining the quality of the supplementary gas injection, the controller further converts this quality into control parameters executable by the gas injector, enabling the gas injector to continuously supply natural gas to the mixer when the engine is in a non-synchronous phase. The controller can calculate the injection parameters based on the current gas pressure and temperature at the gas injector inlet. The current gas pressure and temperature reflect the natural gas supply status before entering the gas injector, and different gas pressures and temperatures affect the injection capacity of the gas injector per unit time. Therefore, with the supplementary gas injection quality determined, the controller can calculate the corresponding opening degree of the gas injector based on the current gas pressure, current gas temperature, and supplementary gas injection quality. The opening degree characterizes the gas injection flow rate of the injector.

[0080] It is also understandable that for vehicle fuel injection systems using continuous-flow injection valves, after determining the opening degree of the fuel injectors, the controller can directly control the fuel injectors to continuously perform supplementary fuel injection according to the corresponding opening degree. For some vehicle fuel injection systems using non-continuous-flow injection valves, such as fuel nozzle systems, supplementary injection control is reflected not only in the opening degree of the fuel injectors but also in the organization of injection time. For example, in such systems, to make the actual supplementary injection effect as close as possible to continuous-flow injection, the jet initiation angle can be ignored during injection control, and a control method similar to that of continuous-flow injectors can be adopted. That is, after the previous fuel injector finishes injecting, the next fuel injector is controlled to inject immediately, thereby forming a cyclical relay injection between the available fuel injectors. Through the above method, an approximately continuous supplementary injection effect can also be formed overall, thereby achieving continuous compensation for the fuel supply during asynchronous phases.

[0081] In this embodiment, by acquiring the engine displacement, the required gas mass can be determined based on the engine displacement, current speed, current intake pressure at the intake manifold inlet, and current intake temperature. By determining the supplementary gas mass based on the current speed, current intake pressure, and required gas mass, compensation and correction of the required gas mass can be achieved based on the current operating conditions, improving the real-time performance and accuracy of determining the supplementary gas mass. By determining the gas injector opening degree based on the current gas pressure and temperature at the gas injector inlet and the supplementary gas mass, the gas injector is controlled to perform supplementary gas injection according to the opening degree until the current operating state is determined to be in a synchronized timing state. This facilitates timely replenishment of an appropriate amount of natural gas during the transition window before startup, when pre-injected gas is gradually consumed and synchronized injection has not yet been established. This maintains the air-fuel ratio in the mixer and intake manifold within a suitable range, thereby improving the engine's starting speed and starting smoothness.

[0082] Example 4 Figure 4 This is a schematic flowchart of a gas injection control method for a vehicle gas injection system according to Embodiment 4 of the present invention. This embodiment supplements the gas injection control method for a vehicle gas injection system based on the above embodiments. Figure 4 As shown, the fuel injection control method of the vehicle fuel injection system in this embodiment may include: S401: Real-time acquisition of the operating status of the vehicle's fuel injection system.

[0083] The operating conditions include at least the engine's operating status and speed, the engine coolant temperature, the intake pressure and temperature at the intake manifold inlet, and the gas pressure and temperature at the gas injector inlet.

[0084] S402. Determine the pre-injected gas quality based on the current operating conditions of the vehicle's gas injection system.

[0085] S403. Based on the current operating conditions and the quality of the pre-injected gas, determine the opening degree and opening time of the gas injector, and control the gas injector to pre-inject gas according to the opening degree and opening time.

[0086] S404. After the gas pre-injection ends, determine whether the current operating condition meets the third preset condition; if so, execute S405.

[0087] The third preset condition includes the engine's current speed being non-zero, the engine's current operating state not being in the fuel cut-off scavenging state, the current gas temperature at the gas injector inlet being lower than a preset temperature threshold, and the duration for which the engine's current speed is lower than a preset speed threshold being less than a third preset time threshold; the fourth preset condition includes the current speed being greater than or equal to a preset speed threshold, or the duration for which the current speed is lower than a preset speed threshold being greater than or equal to a third preset time threshold.

[0088] S405. Adjust the injection mode of the gas injector to quasi-continuous flow injection until the current operating condition meets the fourth preset condition, then adjust the injection mode of the gas injector to pulse injection.

[0089] Specifically, after completing the pre-injection of natural gas before starting, the controller can not only determine whether supplementary injection is needed based on the engine's current operating conditions, but also further determine and switch the injection method of the gas injectors based on the gas temperature and the engine's current speed. It is understandable that for some natural gas engines using discontinuous flow injection valves, such as vehicle gas injection systems using gas nozzles, when the gas temperature is low, the valve core inside the gas injector may freeze or not open sufficiently. This results in the actual amount of natural gas injected into the mixer being lower than the target injection amount, making the mixture entering the cylinder too lean and difficult to ignite reliably, thus affecting the engine's normal starting. Meanwhile, existing pulse-type synchronous injection based on injection timing and duration typically has a low drive frequency for a single injector when the engine is driven by the starter motor and at low speeds. For example, at speeds below 100 rpm, the drive frequency of a single injector is generally only about 1 Hz to 3 Hz. In low-temperature icing scenarios, this low-frequency pulse injection is not conducive to rapid nozzle de-icing and to maintaining a relatively continuous gas supply during the initial starting phase. Therefore, when the gas temperature is too low, quasi-continuous flow injection control should be prioritized during the low engine speed stage, and pulse injection should be temporarily prohibited to improve the jet continuity and ice-breaking capability during the low-temperature start-up stage. This control priority is not based on whether the engine has completed timing synchronization.

[0090] After confirming that the ECU has not been flashed and after verifying that the engine has been stably stationary for a period of time before the start-up, the controller can determine whether the current operating conditions meet the third preset condition. If the controller determines that the current operating conditions meet the third preset condition, it will adjust the injection mode of the gas injector to quasi-continuous flow injection. The third preset condition includes at least the following: the current engine speed is not zero; the current engine operating state is not in the fuel cut-off scavenging state; the current gas temperature at the gas injector inlet is lower than a preset temperature threshold; and the duration for which the current engine speed is lower than the preset speed threshold is less than the third preset time threshold. Specifically, if the engine's current speed is not zero, it indicates that the engine has started to rotate under the starter motor's drive; if the engine's current operating state is not in the fuel cut-off scavenging state, it indicates that gas supply is still allowed and there is no need to restore starting conditions by stopping injection; if the gas temperature is lower than a preset temperature threshold, it indicates that there is a risk of low-temperature icing or insufficient opening of the gas injector. This preset temperature threshold can be in the form of a hysteresis threshold, which can be understood as a threshold setting used to prevent frequent switching of control modes near the temperature critical point. By using hysteresis judgment, the stability of the injection mode switching process can be improved; if the duration of the engine speed being lower than the preset speed threshold is less than the third preset time threshold, it indicates that the engine is still in the normal initial window of low-speed start-up. Within this window, quasi-continuous flow injection is prioritized, which is beneficial for rapid ice breaking and helps the engine establish stable combustion.

[0091] Furthermore, if the controller determines that the current operating condition does not meet the third preset condition, it can switch to the gas supplementary injection control described in the aforementioned embodiment. For example, when the controller determines that the current gas temperature is greater than or equal to a preset temperature threshold, it indicates that there is no significant risk of low-temperature icing. In this case, it is not necessary to prioritize the quasi-continuous flow injection control for rapid ice breaking. Instead, the injection mode is further determined based on the cumulative time of the engine's current timing signal not being synchronized. If the cumulative time of timing signal not being synchronized does not exceed the second preset time threshold, it indicates that the engine is still within a short transition window during the start-up process. In this case, continuous injection can be used to continue supplementing natural gas to the mixer after the pre-injection, thereby maintaining the continuity of the mixture concentration. If the cumulative time of timing signal not being synchronized exceeds the second preset time threshold, it indicates that the engine has not completed timing synchronization for a long time. Continuing to use continuous injection is likely to cause continuous gas accumulation. Therefore, it can be switched to pulse injection to reduce the risk of excessive gas supply and take into account the safety of subsequent start-up.

[0092] After adjusting the gas injector's injection mode to quasi-continuous flow injection, the controller will further determine whether the current operating condition meets a fourth preset condition. If the fourth preset condition is met, the controller will then adjust the gas injector's injection mode to pulse injection. The fourth preset condition includes a current engine speed greater than or equal to a preset speed threshold, or a current engine speed less than a preset speed threshold for a duration greater than or equal to a third preset time threshold. A current engine speed greater than or equal to the preset speed threshold indicates that the engine has established a relatively stable combustion capability during startup, and the engine speed has increased to a higher level. This means the gas injector has completed ice breaking or returned to normal operating conditions, thus allowing the controller to exit quasi-continuous flow injection control and revert to pulse injection control. If the current engine speed is less than the preset speed threshold for a duration greater than or equal to the third preset time threshold, it indicates that the engine has not yet escaped the low-speed state after a period of continuous quasi-continuous flow injection, suggesting that the gas injector nozzles are completely unable to open, or that the gas injector has an internal leakage or other abnormality. In such abnormal situations, continuing to maintain quasi-continuous injection may further exacerbate the risks to the engine and aftertreatment system. Therefore, it is necessary to exit quasi-continuous injection and switch to pulse injection control or other subsequent protection and control strategies.

[0093] By selecting a more suitable gas injection method based on the current operating conditions after the gas pre-injection is completed, the nozzle of the gas injector can be improved to quickly break ice when the gas temperature is low and there is a risk of icing in the gas injector. This also improves the jet continuity during the low-speed start-up phase, thereby further improving the engine's start-up speed and start-up smoothness.

[0094] In this embodiment, after the pre-injection of the gas is completed, the system determines whether the current operating conditions meet the third preset condition. This allows for the priority use of quasi-continuous flow injection control during periods of low gas temperature and low engine speed, thereby improving the continuity of injection and ice-breaking capability during the low-temperature start-up phase and facilitating the rapid establishment of stable combustion in the engine. After adjusting the injection mode of the gas injector to quasi-continuous flow injection, the system determines whether the current operating conditions meet the fourth preset condition. This allows for the adjustment of the gas injector's injection mode to pulse injection when the gas injector has completed ice breaking and returned to normal operation, or when there is an abnormality in the gas injector. This further improves the engine's start-up speed and start-up smoothness.

[0095] Example 5 Figure 5 This is a schematic diagram of the structure of a gas injection control device for a vehicle gas injection system provided in Embodiment 5 of the present invention. This device can implement the gas injection control method for the vehicle gas injection system provided in this embodiment of the invention. The device can be implemented by software and / or hardware, and is generally integrated into the vehicle's controller. Figure 5As shown, the device includes: an operating condition acquisition module 501, a pre-injection gas quality determination module 502, a gas pre-injection control module 503, a supplementary injection gas quality determination module 504, and a gas supplementary injection control module 505. The specific structure of the device is as follows: The operating condition acquisition module 501 is used to acquire the operating condition of the vehicle's gas injection system in real time. The operating condition includes at least the engine's operating status and speed, the engine coolant temperature, the intake pressure and intake temperature at the intake manifold inlet, and the gas pressure and gas temperature at the gas injector inlet.

[0096] The pre-injection gas quality determination module 502 is used to determine the pre-injection gas quality based on the current operating conditions of the vehicle's gas injection system.

[0097] The gas pre-injection control module 503 is used to determine the opening degree and opening time of the gas injector according to the current operating conditions and the quality of the pre-injected gas, and to control the gas injector to perform gas pre-injection according to the opening degree and opening time.

[0098] The supplementary gas injection quality determination module 504 is used to determine the quality of supplementary gas injection based on the current operating conditions after the gas pre-injection is completed.

[0099] The gas supplementary injection control module 505 is used to determine the opening degree of the gas injector based on the current operating conditions and the quality of the supplementary gas, and to control the gas injector to perform supplementary gas injection according to the opening degree until it is determined that the current operating state is in the timing synchronization state.

[0100] In an optional embodiment of the present invention, the pre-injection gas quality determination module 502 may also be used to: determine whether the current operating conditions meet a first preset condition before determining the pre-injection gas quality based on the current operating conditions of the vehicle gas injection system; if so, determine the pre-injection gas quality based on the current operating conditions; wherein the first preset condition includes the duration of the engine's current speed being zero being greater than a first preset time threshold, and the engine's current operating state not being in a fuel cut-off scavenging state.

[0101] In an optional embodiment of the present invention, the pre-injection gas quality determination module 502 may also be used to: obtain the engine displacement and equivalent air-fuel ratio; determine the current air quality in the intake pipe based on the engine displacement, the current intake pressure at the intake pipe inlet, and the current intake temperature; determine the current required gas quality based on the current air quality and equivalent air-fuel ratio; and determine the pre-injection gas quality based on the current engine coolant temperature and the current required gas quality.

[0102] In an optional embodiment of the present invention, the gas pre-injection control module 503 may also be used to: determine the opening degree and opening time of the gas injector based on the current gas pressure and current gas temperature at the gas injector inlet and the pre-injection gas quality.

[0103] In an optional embodiment of the present invention, the supplementary fuel injection quality determination module 504 can also be used to: determine whether the current operating conditions meet a second preset condition before determining the supplementary fuel injection quality based on the current operating conditions; if so, determine the supplementary fuel injection quality based on the current operating conditions; wherein the second preset condition includes the engine's current speed being non-zero, the engine's current operating state not being in a fuel cut-off scavenging state, and the duration of the engine's current operating state being in a non-timing synchronization state being less than a second preset time threshold.

[0104] In an optional embodiment of the present invention, the supplementary fuel injection quality determination module 504 can also be used to: obtain the engine displacement; determine the current required fuel quality based on the engine displacement and current speed, the current intake pressure at the intake manifold inlet and the current intake temperature; and determine the supplementary fuel injection quality based on the current speed, the current intake pressure and the current required fuel quality.

[0105] In an optional embodiment of the present invention, the gas supplementary injection control module 505 can also be used to: determine the opening degree of the gas injector based on the current gas pressure and current gas temperature at the gas injector inlet and the quality of the supplementary injection gas.

[0106] In an optional embodiment of the present invention, the device may further include an injection mode adjustment module, which may be used to: determine whether the current operating condition meets a third preset condition after the gas pre-injection ends; if so, adjust the injection mode of the gas injector to quasi-continuous flow injection until it is determined that the current operating condition meets a fourth preset condition, and then adjust the injection mode of the gas injector to pulse injection; wherein, the third preset condition includes the current engine speed being non-zero, the current engine operating state not being in the fuel cut-off scavenging state, the current gas temperature at the gas injector inlet being lower than a preset temperature threshold, and the duration for which the current engine speed is less than a preset speed threshold being less than a third preset time threshold; the fourth preset condition includes the current speed being greater than or equal to a preset speed threshold, or the duration for which the current speed is less than a preset speed threshold being greater than or equal to a third preset time threshold.

[0107] The gas injection control device for the vehicle gas injection system described above can execute the gas injection control method for the vehicle gas injection system provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the method. Technical details not described in detail in this embodiment can be found in the gas injection control method for the vehicle gas injection system provided in any embodiment of the present invention.

[0108] Since the gas injection control device for the vehicle gas injection system described above is an apparatus capable of executing the gas injection control method for the vehicle gas injection system in the embodiments of the present invention, those skilled in the art can understand the specific implementation and various variations of the gas injection control device for the vehicle gas injection system in this embodiment based on the gas injection control method for the vehicle gas injection system described in the embodiments of the present invention. Therefore, how the gas injection control device for the vehicle gas injection system implements the gas injection control method for the vehicle gas injection system in the embodiments of the present invention will not be described in detail here. Any apparatus used by those skilled in the art to implement the gas injection control method for the vehicle gas injection system in the embodiments of the present invention falls within the scope of protection of this application.

[0109] Example 6 Based on the same inventive concept, embodiments of the present invention also provide a vehicle, the vehicle including: a frame, a vehicle gas injection system disposed within the frame, and a controller.

[0110] The vehicle gas injection system includes at least an engine, a mixer, an intake pipe, and a gas injector. The engine includes multiple cylinders, the mixer is connected to each cylinder through the intake pipe, and the gas injector is used to inject natural gas into the mixer. The controller is connected to the vehicle gas injection system and is used to execute the gas injection control method of the vehicle gas injection system described in the above embodiment.

[0111] Therefore, the vehicle provided in this embodiment has the structure and operation of the gas injection control device of the vehicle gas injection system in the above embodiment, and can achieve the effect of the gas injection control method of the vehicle gas injection system in the above embodiment. The similarities can be referred to the above description, and will not be repeated here.

[0112] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0113] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for controlling fuel injection in a vehicle fuel injection system, characterized in that, The vehicle gas injection system includes at least an engine, a mixer, an intake pipe, and a gas injector. The engine includes multiple cylinders, the mixer is connected to each of the cylinders through the intake pipe, and the gas injector is used to inject natural gas into the mixer. The gas injection control method for the vehicle gas injection system includes: The operating conditions of the vehicle's gas injection system are acquired in real time; the operating conditions include at least the engine's operating status and speed, the engine coolant temperature, the intake pressure and intake temperature at the intake manifold inlet, and the gas pressure and gas temperature at the gas injector inlet. Determine the pre-injected gas quality based on the current operating conditions of the vehicle's gas injection system; Based on the current operating conditions and the quality of the pre-injected gas, determine the opening degree and opening time of the gas injector, and control the gas injector to pre-inject gas according to the opening degree and opening time; After the pre-injection of gas is completed, the quality of supplementary gas injection is determined based on the current operating conditions. Based on the current operating conditions and the quality of the supplementary gas, the opening degree of the gas injector is determined, and the gas injector is controlled to perform supplementary gas injection according to the opening degree until it is determined that the current operating state is in a timing synchronization state.

2. The gas injection control method for a vehicle gas injection system according to claim 1, characterized in that, Before determining the pre-injected fuel quality based on the current operating conditions of the vehicle's fuel injection system, the process also includes: Determine whether the current operating condition meets the first preset condition; if so, determine the pre-injected gas quality based on the current operating condition. The first preset condition includes the duration for which the current engine speed is zero is greater than a first preset time threshold, and the current operating state of the engine is not in the fuel cut-off scavenging state.

3. The gas injection control method for a vehicle gas injection system according to claim 1, characterized in that, Based on the current operating conditions of the vehicle's fuel injection system, the pre-injected fuel quality is determined, including: Obtain the engine's displacement and equivalent air-fuel ratio; The current air mass in the intake pipe is determined based on the engine displacement, the current intake pressure at the intake pipe inlet, and the current intake temperature. Based on the current air quality and the equivalent air-fuel ratio, determine the current required gas mass; The pre-injection gas mass is determined based on the current temperature of the engine coolant and the current required gas mass.

4. The gas injection control method for a vehicle gas injection system according to claim 1, characterized in that, Based on the current operating conditions and the quality of the pre-injected gas, determine the opening degree and opening time of the gas injector, including: The degree of opening and the opening time of the gas injector are determined based on the current gas pressure and temperature at the gas injector inlet and the pre-injected gas quality.

5. The gas injection control method for a vehicle gas injection system according to claim 1, characterized in that, Before determining the quality of the supplementary fuel injection based on the current operating conditions, the process also includes: Determine whether the current operating condition meets the second preset condition; if so, determine the quality of the supplementary gas injection based on the current operating condition. The second preset condition includes the engine's current speed being non-zero, the engine's current operating state not being in the fuel cut-off scavenging state, and the duration of the engine's current operating state being in the non-timing synchronization state being less than the second preset time threshold.

6. The gas injection control method for a vehicle gas injection system according to claim 1, characterized in that, Based on the current operating conditions, the quality of the supplementary fuel injection is determined, including: Obtain the displacement of the engine; The required fuel mass is determined based on the engine displacement and current speed, the current intake pressure at the intake manifold inlet, and the current intake temperature. The mass of supplementary fuel gas is determined based on the current rotational speed, the current intake pressure, and the current required fuel gas mass.

7. The gas injection control method for a vehicle gas injection system according to claim 1, characterized in that, Based on the current operating conditions and the quality of the supplementary injected gas, the degree of opening of the gas injector is determined, including: The degree of opening of the gas injector is determined based on the current gas pressure and temperature at the inlet of the gas injector, as well as the quality of the supplementary gas.

8. The gas injection control method for a vehicle gas injection system according to claim 1, characterized in that, Also includes: After the gas pre-injection is completed, determine whether the current operating condition meets the third preset condition; If so, the injection mode of the gas injector is adjusted to quasi-continuous flow injection until the current operating condition is determined to meet the fourth preset condition, and then the injection mode of the gas injector is adjusted to pulse injection. The third preset condition includes the engine's current speed being non-zero, the engine's current operating state not being in the fuel cut-off scavenging state, the current gas temperature at the gas injector inlet being lower than a preset temperature threshold, and the duration for which the engine's current speed is lower than a preset speed threshold being less than a third preset time threshold. The fourth preset condition includes the current rotational speed being greater than or equal to the preset rotational speed threshold, or the duration during which the current rotational speed is less than the preset rotational speed threshold being greater than or equal to the third preset time threshold.

9. A gas injection control device for a vehicle gas injection system, characterized in that, The vehicle gas injection system includes at least an engine, a mixer, an intake pipe, and a gas injector. The engine includes multiple cylinders, the mixer is connected to each of the cylinders through the intake pipe, and the gas injector is used to inject natural gas into the mixer. The gas injection control device of the vehicle gas injection system includes: The operating condition acquisition module is used to acquire the operating condition of the vehicle's gas injection system in real time; the operating condition includes at least the engine's operating status and speed, the engine coolant temperature, the intake pressure and intake temperature at the intake manifold inlet, and the gas pressure and gas temperature at the gas injector inlet. The pre-injection gas quality determination module is used to determine the pre-injection gas quality based on the current operating conditions of the vehicle's gas injection system. The gas pre-injection control module is used to determine the opening degree and opening time of the gas injector based on the current operating conditions and the quality of the pre-injected gas, and to control the gas injector to perform gas pre-injection according to the opening degree and the opening time. The supplementary gas injection quality determination module is used to determine the quality of supplementary gas injection based on the current operating conditions after the gas pre-injection is completed. The gas supplementary injection control module is used to determine the opening degree of the gas injector based on the current operating conditions and the quality of the supplementary gas, and control the gas injector to perform supplementary gas injection according to the opening degree until it is determined that the current operating state is in a timing synchronization state.

10. A vehicle, characterized in that, include: The vehicle frame, the vehicle fuel injection system housed within the vehicle frame, and the controller; The vehicle gas injection system includes at least an engine, a mixer, an intake pipe, and a gas injector. The engine includes multiple cylinders, the mixer is connected to each of the cylinders through the intake pipe, and the gas injector is used to inject natural gas into the mixer. The controller is connected to the vehicle gas injection system and is used to execute the gas injection control method of the vehicle gas injection system as described in any one of claims 1-8.

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