Method and system for controlling starting fuel of diesel micro-injection ignition natural gas engine

Abstract

The invention relates to a control method and system for starting fuel of a diesel micro-injection ignition natural gas engine, and relates to the field of engines, the engine starting process is divided into a motor driving stage with different rotating speed characteristics, an ignition stage, a rotating speed increasing stage and an idling transition stage; the diesel injection quantity in the motor driving stage is dynamically calculated according to the engine intake density; in the ignition stage, diesel injection amount is gradually reduced, and natural gas injection is introduced; in the rotating speed rising stage, when the rotating speed change rate is large, the natural gas injection amount is reduced, and when the rotating speed change rate is small or even negative, the natural gas injection amount is increased; in the idling transition stage, the diesel oil and natural gas injection amount is linearly and smoothly transited to the target injection amount of the idling working condition; the diesel oil injection amount of each stage is controlled at the micro-injection ignition level, so that the design and model selection of the oil delivery pump only need to meet the micro-injection oil amount requirement during normal operation of the engine. Cooperative injection of diesel oil and natural gas is implemented in stages in the starting process, and the requirement for the oil supply capacity of the oil delivery pump is remarkably lowered.

Description

Technical Field

[0001] This invention relates to the field of engines, and in particular to a method and system for controlling the starting fuel of a diesel micro-injection natural gas engine. Background Technology

[0002] The diesel micro-injection natural gas engine, as a dual-fuel combustion power device, works by injecting a small amount of diesel fuel as ignition fuel during normal engine operation. The compression ignition characteristics of diesel fuel ignite the premixed or directly injected natural gas, the main fuel, achieving efficient and clean combustion. However, current technologies generally employ a pure diesel mode for engine starting.

[0003] Specifically, existing technologies rely entirely on diesel combustion to establish initial operating conditions during the start-up phase, requiring a significantly higher amount of fuel than the micro-injection ignition fuel required during normal operation. Although the engine requires only a very small amount of diesel to ignite natural gas during normal use, the start-up process places far greater demands on the fuel pump's supply capacity than during normal operation. Therefore, the engine system still needs to be matched with a fuel pump with a larger supply capacity to ensure that it can provide sufficient diesel injection during the start-up phase.

[0004] The above solution has problems: the design and selection of the fuel pump must be redundantly configured based on the maximum fuel demand during startup, rather than matching it to the actual micro-injection fuel demand during normal engine operation. This results in significantly higher fuel pump costs and poor system economy. Therefore, how to reduce reliance on the fuel pump's fuel supply capacity and optimize system costs while ensuring reliable engine startup has become an urgent problem to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a fuel control method and system for the starting process of a diesel micro-injection natural gas engine. By implementing the coordinated injection of diesel and natural gas in stages during the starting process, the requirements for the fuel pump's supply capacity are significantly reduced, thereby optimizing system costs. This method ensures reliable engine starting and a smooth transition to idle speed while requiring the fuel pump design to only meet the micro-injection fuel volume requirements during normal operation, and effectively reduces carbon soot and unburned hydrocarbon emissions during the starting phase.

[0006] To achieve the above objectives, the technical solution of the present invention provides a diesel micro-injection ignition natural gas engine starting fuel control method, which divides the engine starting process into a motor-driven stage with different speed characteristics, an ignition stage, a speed rise stage and an idle transition stage.

[0007] During the motor-driven phase, pure diesel injection is used to establish initial combustion, and the diesel injection quantity is dynamically calculated based on the engine intake air density. During the ignition phase, as the engine speed increases, the amount of diesel injection is gradually reduced and natural gas injection is introduced, so that diesel and natural gas form a complementary and synergistic combustion relationship. During the engine speed increase phase, the natural gas injection quantity is dynamically adjusted according to the engine speed change rate. When the speed change rate is large, the natural gas injection quantity is reduced, and when the speed change rate is small, the natural gas injection quantity is increased. During the idling transition phase, the diesel and natural gas injection quantities are linearly and smoothly transitioned to the target injection quantities for idling conditions. In this process, the diesel injection volume in each of the above stages is controlled at the micro-injection ignition level, so that the design and selection of the fuel pump only needs to meet the micro-injection fuel volume requirements when the engine is running normally.

[0008] Preferably, during the motor-driven phase, the diesel single-cylinder cyclic injection quantity... Based on the engine's single-cylinder displacement V and the actual intake air density of the cylinder Theoretical air-fuel ratio of diesel fuel Diesel density and the maximum single-cylinder circulating injection volume of the oil pump design Real-time calculations show that the natural gas injection volume is zero.

[0009] Preferably, during the ignition phase, the diesel single-cylinder cyclic injection quantity... The amount of natural gas injected per cylinder decreases linearly with increasing engine speed. It increases with increasing rotational speed, and It is directly proportional to the intake air volume and inversely proportional to the engine speed.

[0010] Preferably, during the speed increase phase, the diesel single-cylinder cyclic injection quantity Further reduced to micro-injection level, natural gas single-cylinder cycle injection volume The speed is dynamically adjusted based on the ratio of the rate of change of rotational speed between two adjacent injections to suppress speed spikes or accelerate speed increases.

[0011] Preferably, during the idling transition phase, the diesel single-cylinder cycle injection quantity... and natural gas single-cylinder cycle injection volume Linear interpolation is used to smoothly transition to the pre-calibrated target injection quantity at idle speed. and .

[0012] Preferably, the actual intake air density of the cylinder Cylinder intake pressure measured by intake air temperature and pressure sensor and intake air temperature Obtained through calculation.

[0013] Preferably, during the ignition stage, the speed increase stage, and the idling transition stage, ambient temperature compensation is introduced for the calculated diesel injection quantity and natural gas injection quantity. The compensation coefficient is related to the engine coolant temperature and is corrected with reference to the design reference temperature.

[0014] Preferably, it also includes a voltage compensation mechanism, which obtains the voltage compensation coefficient by querying a pre-calibrated voltage compensation MAP. The diesel and natural gas injection quantities are corrected to compensate for the changes in the response characteristics of the injector solenoid valve and the natural gas injection valve under different voltages.

[0015] The technical solution of the present invention also provides a starting fuel control system for a diesel micro-injection ignition natural gas engine, comprising: Engine electronic control unit; Crankshaft position sensor used to detect engine speed and rate of change of speed; Used to detect cylinder intake pressure and intake air temperature The intake air temperature and pressure sensor; Coolant temperature sensor used to detect engine coolant temperature; A voltage sensor used to detect the voltage of a storage battery; Diesel injectors and natural gas injection valves; The engine electronic control unit is configured to execute the aforementioned diesel micro-injection ignition natural gas engine starting fuel control method, which achieves staged fuel injection by controlling the diesel injector and the natural gas injection valve.

[0016] Preferably, the diesel injector is a micro-injection ignition type injector, and the natural gas injection valve is an electronically controlled high-precision injection valve. The response characteristic data of both are pre-calibrated and stored in the voltage compensation MAP.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: This invention scientifically decomposes the engine starting process into four consecutive stages with different speed characteristics and combustion requirements, and precisely matches a coordinated injection strategy of diesel and natural gas for each stage. This fundamentally changes the traditional pure diesel starting mode that relies on large-volume fuel injection. In the initial stage of starting, the initial combustion is mainly established by the easy-to-ignite characteristics of diesel. As the speed increases, natural gas is gradually introduced to assist in a smooth increase in speed. This ensures that the diesel injection quantity is always controlled at a micro-injection ignition level throughout the starting process, significantly reducing the design requirements for the fuel pump's fuel supply capacity. It also solves the problem of increased system costs caused by the fuel pump having to reserve redundant capacity for excessive starting fuel volume in traditional starting methods.

[0018] Based on the above control strategy, the development and matching of the fuel pump only needs to meet the micro-injection fuel volume requirements during normal engine operation, without considering the peak fuel volume at startup, thus achieving hardware specification optimization and cost reduction. Compared with the traditional pure diesel starting method, the weight and volume of the fuel pump can be reduced by about 15% and the cost by about 20% after adopting this invention, which has direct and significant economic benefits. At the same time, the miniaturization of the pump body also helps to improve the flexibility of the overall machine layout.

[0019] Furthermore, since natural gas is introduced into the combustion process during startup, emissions of soot and unburned hydrocarbons caused by localized rich combustion during pure diesel startup are effectively reduced, offering environmental advantages. The smooth transition and closed-loop control of fuel supply throughout the startup process ensure the engine's starting reliability and speed stability under harsh conditions such as cold environments or aging batteries, achieving a balance between economy, environmental friendliness, and power performance. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the starting fuel control method and system for a diesel micro-injection ignition natural gas engine according to the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0022] Example 1: This invention discloses a fuel control method for starting a diesel micro-injection natural gas engine. By scientifically decomposing the engine starting process into four consecutive stages with different speed characteristics and combustion requirements, and precisely matching the corresponding diesel and natural gas injection strategies for each stage, the method significantly reduces the requirements for the fuel pump's fuel supply capacity while ensuring reliable engine starting, thereby optimizing system costs.

[0023] The core technical idea of ​​this method is to change the single strategy of relying solely on large-volume fuel injection for starting in the traditional pure diesel starting mode, and instead adopt a mixed fuel supply method that combines diesel and natural gas. In the initial stage of starting, the initial combustion is mainly established by relying on the easy-to-ignite characteristics of diesel. As the speed increases, natural gas is gradually introduced and its combustion characteristics are used to assist the speed to rise steadily, and finally smoothly transition to the idling condition. Throughout the process, the design and selection of the fuel pump only needs to meet the micro-injection ignition requirements during normal engine operation, without reserving redundancy for excessive starting fuel volume.

[0024] Specifically, the engine electronic control unit (ECU) first divides the starting process into four stages: ① starter motor stage, ② ignition stage, ③ speed increase stage, and ④ idle transition stage.

[0025] ① Motor-driven stage The engine crankshaft is driven entirely by the starter motor, and the speed gradually increases from rest to the preset first speed threshold. At this speed of r / min, the cylinder temperature is relatively low and the combustion chamber walls lose a significant amount of heat. To ensure reliable compression ignition of diesel fuel, a pure diesel injection strategy is employed in this stage without introducing natural gas. The diesel injection volume per cylinder cycle is... (mm) 3 The calculation is obtained by the ECU in real time based on the engine's physical parameters. The calculation formula fully considers the actual intake air density of the cylinder and the design limits of the fuel pump. +

[0026] Where V represents the engine's single-cylinder displacement (in liters). The theoretical air-fuel ratio for diesel is taken as 18. The density of diesel fuel is taken as 0.84 g / cm³. 3 , Maximum single-cylinder injection volume (in mm) designed for the oil pump 3 ), where n is the current real-time engine speed (in r / min). Air density (unit: kg / m³) 3 The air density is determined by the ECU using the cylinder intake pressure measured by an intake air temperature and pressure sensor installed on the engine intake manifold. (Unit: kPa, absolute pressure) and intake air temperature (Unit: °C) is then calculated, and the specific calculation formula is as follows:

[0027] At this stage, the natural gas single-cylinder cycle injection volume Keeping the speed at zero, the ECU controls the natural gas injection valve to remain closed, ensuring that only atomized diesel fuel exists in the cylinder. When the engine speed reaches... The first stage ends when the cylinder has established a preliminary combustion temperature and pressure environment.

[0028] ②Ignition stage Engine speed range is to Between 100 rpm and 200 rpm, combustion has been initially established but is not yet stable. The ECU uses engine speed as the core control parameter and implements a diesel-natural gas proportional injection strategy. The diesel injection quantity gradually decreases as the engine speed increases, while the natural gas injection quantity gradually increases, forming a complementary relationship. The diesel single-cylinder cycle injection quantity... It is calculated using the following formula:

[0029] This formula ensures that the diesel injection quantity decreases linearly from the higher level of the first stage to a more economical micro-injection level, while the natural gas single-cylinder cycle injection quantity... Initially introduced, its value is determined by the following formula:

[0030] in The equivalence air-fuel ratio (EFR) for natural gas is set at 16.7 (it should be noted that the EFR value may vary depending on the natural gas composition; the actual EFR value corresponding to the specific gas composition should be used). This calculation method makes the natural gas injection quantity directly proportional to the intake air charge and inversely proportional to the engine speed. At lower engine speeds, the natural gas quantity is appropriately increased to avoid misfires. During this phase, the ECU continuously monitors engine speed changes; when the engine speed exceeds... Then we enter the third stage.

[0031] ③Rising speed stage Engine speed range extended to to The core control objective at this stage is to prevent runaway engine speed spikes due to excessive natural gas injection while ensuring a rapid and stable increase in engine speed. Therefore, the ECU uses the engine speed change rate as the core feedback parameter for dynamic adjustment. When the engine speed change rate is large, the amount of natural gas injected is reduced to prevent the engine speed from spikeing; when the engine speed change rate is small or negative, it indicates that the engine speed is rising slowly or even decreasing, so the injection amount is increased proportionally to accelerate the rate of engine speed increase.

[0032] Diesel single-cylinder cycle injection quantity Continue decreasing according to the preset pattern, the specific calculation formula is as follows: )-

[0033] This formula further subtracts the fuel quantity related to the increase in engine speed from the diesel injection quantity at the end of the second stage, allowing diesel injection to enter the micro-injection state earlier, and the natural gas single-cylinder cycle injection quantity... A more refined adjustment strategy is then adopted, calculated using the following formula:

[0034] in Representative at to The rate of change of rotational speed corresponding to the i-th natural gas injection within the rotational speed range. These two parameters—the rate of change of engine speed corresponding to the (i+1)th natural gas injection—are calculated in real-time by the ECU based on signals from the crankshaft position sensor. and These are the actual engine speeds during the i-th and i+1-th natural gas injections, respectively. The physical meaning of this formula is that when the speed change rate is large, the amplification effect of the proportional term reduces the natural gas injection quantity accordingly, thereby suppressing the excessive speed increase. When the speed change rate is small or negative, the natural gas injection quantity will increase proportionally to accelerate the speed increase. This feedforward-feedback composite control method based on the speed change rate effectively ensures the smoothness and speed of the starting process.

[0035] ④ Idle transition stage The engine speed was further increased to The speed increases by r / min and approaches the target idle speed n (idle speed). The speed range during this stage is... to The ECU's control objective is to smoothly and gradually transition the injection quantity of diesel and natural gas to the target injection quantity under idle conditions, avoiding speed fluctuations caused by sudden changes in fuel supply. Diesel single-cylinder cycle injection quantity. (mm) 3 The calculation is performed using linear interpolation, and the specific formula is as follows:

[0036] Where n_idle_speed represents the target idle speed of the engine. Rotational speed The diesel injection transition reference quantity at any given moment. It is calculated using the following formula: )- ) This represents the basic diesel injection quantity corresponding to the pre-calibrated target idle speed, and the natural gas single-cylinder cycle injection quantity. Similarly, a linear smooth transition strategy is adopted, determined by the following formula.

[0037] in Rotational speed Natural gas injection volume at any given time The two reference injection quantities for the target idle speed are pre-stored in the ECU's MAP diagram through engine bench calibration tests. This linear transition method ensures that as the actual speed n gradually approaches the target idle speed n, (n- As the injection rate gradually increases, the injection volume gradually approaches the idle speed setting value, thus achieving a seamless transition from starting condition to idle condition.

[0038] Considering the significant impact of ambient temperature on the rate of fuel evaporation, mixing, and combustion in the cylinder during practical applications, as well as the direct impact of battery voltage fluctuations on the response speed of the diesel injector solenoid valve and the opening and closing characteristics of the natural gas injection valve, this invention further introduces ambient temperature compensation and voltage compensation correction mechanisms based on the calculation results of diesel injection quantity and natural gas injection quantity during the ignition stage, the speed increase stage, and the idle transition stage.

[0039] The ECU collects the coolant temperature T (in °C) measured by the engine coolant temperature sensor and the current voltage value measured by the battery voltage sensor in real time, and obtains the voltage compensation coefficient by interpolation through a lookup table. This coefficient comprehensively reflects the opening delay and flow attenuation characteristics of the injector solenoid valve and natural gas injection valve under different voltages. After experimental calibration, it forms a voltage compensation MAP and is stored in the ECU. The corrected diesel single-cylinder injection quantity and natural gas single-cylinder injection quantity are calculated uniformly according to the following formula:

[0040]

[0041] in This can be obtained by consulting the voltage compensation tables for the diesel injector solenoid valve and the natural gas injection valve, based on the actual battery voltage. The temperature is measured by the engine's coolant temperature sensor. This reflects the physical essence of temperature correction: using 85℃ as the design reference temperature, the injection volume is increased when the actual water temperature is lower than this value to compensate for the decrease in combustion efficiency, and the injection volume is appropriately reduced when the water temperature is higher than this value to prevent excessive combustion. When the voltage is low, the coefficient is increased to compensate for the flow loss, ensuring that the actual amount of fuel injected into the cylinder under each operating condition always meets the theoretical calculation requirements, thereby ensuring that the engine can maintain good starting reliability and speed stability under harsh conditions such as cold environment or battery aging.

[0042] Through the four-stage, progressive fuel control strategy described above, this invention achieves the optimal ratio of diesel and natural gas during the starting process. Initially, diesel is the primary fuel to ensure reliable ignition. In the middle stage, natural gas is introduced and precise closed-loop control is implemented based on engine speed and its rate of change. Finally, the system smoothly transitions to idle conditions. Throughout the starting process, the diesel injection quantity is always controlled at the micro-injection level, while the natural gas injection quantity is dynamically adjusted according to the engine status. This ensures both rapid and stable starting and allows the fuel pump design to be based solely on the maximum micro-injection fuel demand during normal engine operation. Compared to traditional pure diesel starting methods, the weight and volume of the fuel pump can be reduced by approximately 15%, and the cost by approximately 20%. Furthermore, since natural gas is introduced into the combustion process during the starting stage, the emissions of carbon soot and unburned hydrocarbons during pure diesel starting are effectively reduced, offering both economic and environmental advantages.

[0043] Example 2: Based on Example 1, this example discloses a diesel micro-injection ignition natural gas engine starting fuel control system, which is used to execute the fuel control method in Example 1. Through integrated hardware configuration and modular software control logic, it realizes four-stage precise fuel management in the starting process.

[0044] The system includes an engine electronic control unit (ECU), a sensing unit, an actuator unit, and auxiliary components. The sensing unit consists of an intake air temperature and pressure sensor, a crankshaft position sensor, a coolant temperature sensor, and a battery voltage sensor; the actuator unit includes a diesel injector, a natural gas injection valve, and a starter motor; and the auxiliary components include the engine block, a fuel pump, and a battery.

[0045] The engine electronic control unit (ECU), as the core of the system, establishes electrical connections with the aforementioned sensors and actuators via wiring harnesses. The intake air temperature and pressure sensor is installed in the engine intake manifold to collect real-time cylinder intake pressure data. and intake air temperature And transmit it to the ECU for calculating air density. The crankshaft position sensor is mounted on the engine flywheel housing, continuously monitoring the crankshaft angular position and outputting a pulse signal. The ECU uses this signal to calculate the current real-time engine speed n and the rate of change of engine speed within adjacent injection cycles. The coolant temperature sensor is installed in the engine cooling system piping to measure the coolant temperature (Twater temperature) and send the data to the ECU. The battery voltage sensor is connected in parallel to the positive and negative terminals of the battery to monitor the current voltage value in real time.

[0046] The diesel injector is a micro-injection type electronically controlled injector, installed in the cylinder head of each cylinder of the engine, with a maximum designed single-cylinder cycle injection volume of [missing information]. The response characteristics are pre-calibrated using a voltage-compensated MAP. The natural gas injection valve is an electronically controlled high-precision injection valve, installed in the intake manifold of each cylinder, and its flow characteristics are also pre-stored in the ECU's voltage-compensated MAP. The starter motor is connected to the engine crankshaft via a gear meshing mechanism, providing driving torque during the motor-driven phase.

[0047] With the above system configuration, the design and selection of the fuel pump only needs to meet the maximum micro-injection volume requirement during normal engine operation, without reserving redundancy for the starting process. Compared with the traditional pure diesel starting system, the weight and volume of the fuel pump are reduced by about 15%, and the cost is reduced by about 20%. At the same time, the introduction of natural gas to participate in combustion during the starting stage effectively reduces the emissions of soot and unburned hydrocarbons during pure diesel starting.

[0048] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for controlling the starting fuel of a diesel micro-injection natural gas engine, characterized in that, The engine starting process is divided into four stages with different speed characteristics: the motor-driven stage, the ignition stage, the speed rise stage, and the idle transition stage. During the motor-driven phase, pure diesel injection is used to establish initial combustion, and the diesel injection quantity is dynamically calculated based on the engine intake air density. During the ignition phase, as the engine speed increases, the amount of diesel injection is gradually reduced and natural gas injection is introduced, so that diesel and natural gas form a complementary and synergistic combustion relationship. During the engine speed increase phase, the natural gas injection quantity is dynamically adjusted according to the engine speed change rate. When the speed change rate is large, the natural gas injection quantity is reduced, and when the speed change rate is small or even negative, the natural gas injection quantity is increased. During the idling transition phase, the diesel and natural gas injection quantities are linearly and smoothly transitioned to the target injection quantities for idling conditions. In this process, the diesel injection volume in each of the above stages is controlled at the micro-injection ignition level, so that the design and selection of the fuel pump only needs to meet the micro-injection fuel volume requirements when the engine is running normally.

2. The method for controlling the starting fuel of a diesel micro-injection natural gas engine according to claim 1, characterized in that, During the motor-driven phase, the diesel single-cylinder cyclic injection quantity Based on the engine's single-cylinder displacement V and the actual intake air density of the cylinder Theoretical air-fuel ratio of diesel fuel Diesel density and the maximum single-cylinder circulating injection volume of the oil pump design Real-time calculations show that the natural gas injection volume is zero.

3. The method for controlling the starting fuel of a diesel micro-injection natural gas engine according to claim 1, characterized in that, During the ignition phase, the diesel single-cylinder cycle injection quantity The amount of natural gas injected per cylinder decreases linearly with increasing engine speed. It increases with increasing rotational speed, and It is directly proportional to the intake air volume and inversely proportional to the engine speed.

4. The method for controlling the starting fuel of a diesel micro-injection natural gas engine according to claim 1, characterized in that, During the engine speed increase phase, the diesel single-cylinder cycle injection quantity Further reduced to micro-injection level, natural gas single-cylinder cycle injection volume Dynamic adjustments are made based on the rate of change of rotational speed between two adjacent injections to suppress speed spikes or accelerate speed increases.

5. The method for controlling the starting fuel of a diesel micro-injection natural gas engine according to claim 4, characterized in that, During the idling transition phase, the diesel single-cylinder injection quantity and natural gas single-cylinder cycle injection volume Linear interpolation is used to smoothly transition to the pre-calibrated target injection quantity at idle speed. and .

6. The method for controlling the starting fuel of a diesel micro-injection natural gas engine according to claim 2, characterized in that, Actual intake density of cylinder Cylinder intake pressure measured by intake air temperature and pressure sensor and intake air temperature Obtained through calculation.

7. A method for controlling the starting fuel of a diesel micro-injection natural gas engine according to any one of claims 1-6, characterized in that, During the ignition, speed increase, and idling transition phases, ambient temperature compensation is introduced for the calculated diesel and natural gas injection quantities. The compensation coefficient is related to the engine coolant temperature and is corrected with reference to the design reference temperature.

8. The method for controlling the starting fuel of a diesel micro-injection natural gas engine according to claim 7, characterized in that, It also includes a voltage compensation mechanism, which obtains the voltage compensation coefficient by querying a pre-calibrated voltage compensation MAP. The diesel and natural gas injection quantities are corrected to compensate for the changes in the response characteristics of the injector solenoid valve and the natural gas injection valve under different voltages.

9. A starting fuel control system for a diesel micro-injection ignition natural gas engine, characterized in that, include: Engine electronic control unit; Crankshaft position sensor used to detect engine speed and rate of change of speed; Used to detect cylinder intake pressure and intake air temperature The intake air temperature and pressure sensor; Coolant temperature sensor used to detect engine coolant temperature; A voltage sensor used to detect the voltage of a storage battery; Diesel injectors and natural gas injection valves; The engine electronic control unit is configured to execute the diesel micro-injection ignition natural gas engine starting fuel control method according to any one of claims 1-8, and to achieve staged fuel injection by controlling the diesel injector and the natural gas injection valve.

10. A diesel micro-injection ignition natural gas engine starting fuel control system according to claim 9, characterized in that, The diesel injector is a micro-injection ignition type injector, and the natural gas injection valve is an electronically controlled high-precision injection valve. The response characteristic data of both are pre-calibrated and stored in the voltage compensation MAP.

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