Control system method and apparatus for phase iv compliant anti-knock diesel engines

Abstract

This invention provides a method and device for a control system for explosion-proof diesel engines suitable for Stage IV emissions, belonging to the field of control technology for explosion-proof diesel engines used in mining. The overall solution consists of a hardware adaptation system and a software control strategy: The hardware is based on a non-road National IV diesel engine that adopts the EGR+DOC+DPF emission technology route and does not have an SCR system. All sensors and actuators have obtained safety certification for mining products. The water-cooled turbocharger is replaced and a wet exhaust system is matched. The ECU is installed in an explosion-proof cavity that conforms to the GB / T3836-2021 standard. The software has three core modules: high-altitude adaptive and temperature protection, DPF active regeneration management, and EGR closed-loop and open-loop composite control. High-altitude fuel quantity limitation is achieved by indirectly obtaining atmospheric pressure by reading the intake air pressure when the engine is not running. Passive regeneration of DPF is permanently closed, and only manual active regeneration is retained. The speed-density method is used to replace the air flow sensor to achieve precise EGR control.

Description

Technical Field

[0001] This invention relates to the field of control technology for explosion-proof diesel engines used in mining, and more particularly to a control system method and apparatus for explosion-proof diesel engines suitable for Stage IV emissions. Background Technology

[0002] Currently, explosion-proof diesel engines meet the non-road China III emission standards. However, with the development needs of energy conservation, emission reduction, green mining, and people-oriented development, and according to the latest implementation rules for the review and issuance of safety marks for explosion-proof diesel engines issued by the National Mining Product Safety Mark Center Co., Ltd., a fourth-stage emission standard for explosion-proof diesel engines has been added. The standards for the fourth stage are MT990-2006, GB20891-2014, and HJ1014-2020. Compared to the third-stage explosion-proof diesel engines, GB20891-2014 implements the fourth-stage emission standard, while HJ1014-2020 adds a completely new requirement. This includes requirements for dry emissions for explosion-proof diesel engines and requirements for high-altitude use (intake, automatic protection, and exhaust emissions above 1500m). It is clearly required that the emission technology used in the fourth-stage explosion-proof diesel engine be consistent with the original engine. Furthermore, mining explosion-proof diesel engines are prohibited from using SCR systems.

[0003] According to the new standard, current off-road vehicle control systems cannot meet the requirements for Stage IV use of explosion-proof diesel engines, mainly for two reasons: First, the non-road stage 4 diesel engine system contains a variety of sensors and actuators, and some sensors cannot meet the requirements of GB / T3836-2021 "Explosive Atmospheres". After replacing the sensors and actuators with those that meet the safety standards, the ECU cannot control the engine normally.

[0004] Secondly, the control strategies of the non-road stage four controller software, such as the active regeneration function of DPF or the SCR system, cannot be applied in explosion-proof diesel engines. After removing the relevant components, the control system will limit the power output, and the engine will not be able to work normally.

[0005] In addition, because the explosion-proof diesel engine ECU is installed in the explosion-proof cavity of the fuel injection electronic control device and is not in contact with the outside atmosphere, the atmospheric pressure sensor built into the non-road China IV ECU cannot be used in the explosion-proof diesel engine system, which poses certain problems when used at high altitudes. Summary of the Invention

[0006] In view of this, the present invention provides a method and apparatus for a control system for explosion-proof diesel engines suitable for Stage IV emissions, to solve the problem that existing non-road Stage IV diesel engine control systems cannot meet the Stage IV emission and safety requirements of mining explosion-proof diesel engines, specifically including: The existing non-road China IV emission standard system has some sensors and actuators that do not meet the requirements of GB / T3836-2021 "Explosive Atmospheres". After replacing them with safety-certified products, the ECU cannot control the engine normally. The original DPF passive regeneration function poses a safety hazard in the flammable and explosive environment of mines. After canceling the relevant function, the engine power output is limited. The ECU is installed in the explosion-proof cavity of the fuel injection electronic control device, which causes the onboard atmospheric pressure sensor to fail. When used at high altitudes, there are safety risks in intake air measurement, fuel quantity control and surface temperature control. There are no automotive-grade air flow sensors with mining safety certification, and the original EGR closed-loop control cannot be achieved.

[0007] The technical solution proposed in this invention is as follows: Methods and apparatus for explosion-proof diesel engine control systems applicable to Stage IV emissions, specifically including hardware adaptation schemes and software control strategies; The hardware adaptation scheme is based on a non-road China IV diesel engine that adopts the EGR+DOC+DPF emission technology route and does not have an SCR system. It selects safety-certified sensors and actuators to replace the corresponding parts of the original engine, replaces the water-cooled turbocharger and matches the wet exhaust system, and installs the ECU of the fuel injection electronic control device in an explosion-proof cavity that conforms to the GB / T3836-2021 standard. The software control strategy is embedded in the ECU, and its core includes three major modules: high-altitude adaptive and temperature protection control, DPF active regeneration control, and EGR closed-loop and open-loop composite control.

[0008] Furthermore, in the aforementioned hardware adaptation scheme, the engine crankshaft position sensor, camshaft position sensor, intake air temperature and pressure sensor, coolant temperature sensor, oil pressure sensor, accelerator pedal position sensor, injector, oil pump metering valve, EGR valve, and DOC temperature sensor are all selected as explosion-proof or intrinsically safe products that have obtained mining product safety mark certification, and the characteristic parameters of the above components are recalibrated in the ECU.

[0009] Furthermore, in the hardware adaptation scheme, the original universal DPF differential pressure sensor is removed and replaced with an explosion-proof or intrinsically safe differential pressure sensor that has been certified by safety standards. The signal channel is rematched and the corresponding characteristic parameters are adjusted in the ECU. At the same time, the original vehicle external ambient temperature sensor is removed to reduce the introduction of non-explosion-proof components.

[0010] Furthermore, in the software control strategy, when the ECU is powered on but the engine is not started, the value of the intake pressure sensor is read as the current ambient atmospheric pressure value and stored in non-volatile memory, taking advantage of the characteristic that the pressure inside the intake manifold is balanced with the external atmospheric pressure. This value is used to replace the data from the onboard atmospheric pressure sensor of the ECU for subsequent altitude calculation.

[0011] Furthermore, in the high-altitude adaptive and temperature protection control, the ECU calculates the current altitude based on the acquired ambient atmospheric pressure value, queries the preset altitude-maximum fuel injection quantity mapping map, and automatically limits the maximum cycle fuel injection quantity of the engine as the altitude increases, maintaining the air-fuel ratio within a safe range and preventing the exhaust temperature from becoming too high.

[0012] Furthermore, in the high-altitude adaptive and temperature protection control, the ECU communicates bidirectionally with the vehicle protection device via the CAN bus, and receives the engine surface temperature data transmitted by the vehicle protection device in real time. The ECU has preset surface temperature warning thresholds and shutdown thresholds.

[0013] Furthermore, in the high-altitude adaptive and temperature protection control, when the engine surface temperature reaches the warning threshold, the ECU actively reduces the engine output power; when the engine surface temperature reaches the shutdown threshold, the ECU performs an automatic fuel cut-off shutdown operation and sends a fault code to the vehicle protection device via the CAN bus, triggering an audible and visual alarm.

[0014] Furthermore, in the DPF active regeneration control, the DPF passive regeneration function is permanently disabled at the software level, and only the controllable active regeneration function is retained; the ECU reads the value of the safety-certified DPF differential pressure sensor in real time and compares it with the preset regeneration threshold corresponding to different DPF carbon loads.

[0015] Furthermore, in the DPF active regeneration control, when the DPF pressure difference reaches the regeneration threshold, the ECU sends a regeneration request to the vehicle protection device via the CAN bus, triggers an audible and visual alarm, and prompts the driver via the display to move the vehicle to a safe location in the well with no flammable materials and good ventilation. After confirming that the environment is safe, the ECU controls the injectors to perform post-injection to increase the exhaust temperature and executes DPF active regeneration.

[0016] Furthermore, in the EGR closed-loop and open-loop composite control, the velocity-density method is used in conjunction with intake manifold pressure, intake air temperature and engine speed to calculate the total mass of the air-fuel mixture entering the cylinder, and the mass of fresh air is estimated based on the volumetric efficiency model, replacing the original air flow sensor to achieve EGR closed-loop control; at the same time, a basic mapping map of EGR open-loop control based on engine speed and cyclic fuel injection quantity is established, and an atmospheric pressure correction coefficient is introduced to compensate for altitude of the EGR valve open-loop opening.

[0017] The method and apparatus for an explosion-proof diesel engine control system applicable to Stage IV emissions provided by this invention have the following beneficial effects: In use, this invention achieves successful adaptation of non-road China IV diesel engine technology to the field of explosion-proof mining through the coordinated optimization of hardware adaptation and software control strategies. While meeting the GB20891-2014 and HJ1014-2020 fourth-stage emission standards, it fully complies with the explosion-proof safety requirements for mining. The innovative solution of replacing the onboard atmospheric pressure sensor with an intake pressure sensor solves the problem of altitude detection failure caused by ECU explosion-proof installation. Combined with altitude-injection quantity mapping control and engine surface temperature linkage protection, it effectively avoids the safety risks of excessive exhaust temperature and engine surface temperature during high-altitude use. By disabling passive DPF regeneration and retaining only active regeneration executed after manual confirmation, the safety hazards of regeneration in flammable and explosive underground environments are completely eliminated. The EGR composite control scheme, which replaces the air flow sensor with a velocity-density method, achieves precise EGR control even without a certified air flow sensor, ensuring stable emission performance across the entire altitude range. The overall solution requires no major structural modifications to the original engine; it can be implemented simply by matching existing certified products and optimizing the control strategy. It features low cost, high reliability, and strong practicality, and can be quickly deployed and applied to various types of explosion-proof diesel engine vehicles used in mining. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments will be briefly described below.

[0019] The accompanying drawings described below are only related to some embodiments of the invention and are not intended to limit the invention.

[0020] In the attached diagram: Figure 1 The diagram shows the overall layout of the control system for the National IV explosion-proof diesel engine of this invention; Figure 2 A schematic diagram of the control device applicable to the National IV explosion-proof diesel engine of the present invention is shown; Figure 3 The atmospheric pressure value reading strategy of this invention is illustrated; Figure 4 This illustrates the high-altitude adaptive and temperature protection control logic of the present invention; Figure 5 The EGR closed-loop control logic of this invention is shown; Figure 6 The interactive control strategy of the regeneration control and protection device of the present invention is shown. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the described embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0022] This invention addresses the shortcomings of existing non-road China IV diesel engine control systems, which are unable to adapt to the fourth-stage emission and safety requirements of mining explosion-proof diesel engines. Through the coordinated optimization of hardware adaptation selection and software control strategies, it realizes the practical application of non-road China IV technology in the field of mining explosion-proof applications, while meeting the relevant provisions of GB20891-2014 "Emission Limits and Measurement Methods for Exhaust Pollutants from Diesel Engines for Non-Road Mobile Machinery (China Stage III and IV)", HJ1014-2020 "Technical Requirements for Pollutant Emission Control of Non-Road Diesel Mobile Machinery", and GB / T3836-2021 "Explosive Atmospheres".

[0023] Example 1: Specific Construction of Hardware Device for Explosion-proof Diesel Engine Control System The explosion-proof diesel engine control system device for Stage IV emissions provided in this embodiment mainly consists of five parts: explosion-proof diesel engine body, fuel injection electronic control device, vehicle protection device, exhaust aftertreatment system, and sensor actuator assembly.

[0024] Selection and modification of explosion-proof diesel engine body: The original diesel engine selected meets the fourth stage emission standard for non-road mobile machinery. Its basic emission technology route is EGR (exhaust gas recirculation) + DOC (oxidation catalyst) + DPF (particulate filter). The original engine is not equipped with an SCR (selective catalytic reduction) urea injection system, which fully complies with the mandatory requirement that mining explosion-proof diesel engines must not use urea systems.

[0025] Two core modifications were made to the original machine: The original air-cooled turbocharger was replaced with a water-cooled turbocharger. The heat of the turbocharger housing was removed by the engine coolant circulation, and the surface temperature of the turbocharger was controlled below 150°C, which meets the surface temperature limit requirements of the mining explosion-proof diesel engine. A wet exhaust system is matched at the exhaust end, which sprays water to directly contact the high-temperature exhaust, reducing the exhaust temperature to below 70°C, while eliminating sparks in the exhaust and eliminating ignition sources in the flammable and explosive environment underground.

[0026] Installation of fuel injection electronic control unit: The fuel injection electronic control unit has a built-in core control unit ECU. The entire unit is installed in an explosion-proof cavity that conforms to the GB / T3836-2021 standard. The explosion-proof cavity has an explosion-proof rating of ExdⅠMb, which is suitable for explosive gas environments in underground coal mines.

[0027] Since the explosion-proof cavity is a completely sealed structure and has no connection with the outside atmosphere, the atmospheric pressure sensor integrated on the ECU board cannot detect the real ambient atmospheric pressure. Therefore, this system does not rely on this onboard sensor to determine altitude, but instead achieves indirect measurement of atmospheric pressure through subsequent software strategies.

[0028] Sensor and actuator adapter selection: All sensor and actuator components are selected from explosion-proof or intrinsically safe products that have obtained the Mining Product Safety Mark (MA) certification. Specific selection and adaptation requirements are as follows: Basic sensors: crankshaft position sensor, camshaft position sensor, intake air temperature and pressure sensor, coolant temperature sensor, oil pressure sensor, accelerator pedal position sensor, and DOC temperature sensor. All of them are intrinsically safe products (ExiaⅠMb), and their output characteristic curves are recalibrated in the ECU to ensure signal acquisition accuracy. Actuators: Injectors, fuel pump metering valves, and EGR valves are all selected as explosion-proof products (ExdⅠMb), and the drive current and response time parameters of the ECU are rematched; DPF differential pressure sensor: The original general-purpose automotive-grade differential pressure sensor has been replaced with a safety-certified explosion-proof differential pressure sensor with a measurement range of 0~50kPa and an accuracy of ±2%FS; the analog input channels in the ECU have been reallocated, and the signal filtering parameters and range conversion coefficients have been adjusted. The original vehicle's external ambient temperature sensor was removed, reducing the introduction of non-explosion-proof components and lowering system safety risks.

[0029] Communication connection: The ECU in the fuel injection electronic control unit establishes a bidirectional communication connection with the main controller of the vehicle protection device via the CAN2.0B bus. The communication baud rate is 250kbps, which conforms to the CAN communication standard for mining equipment. The communication data includes: operating parameters such as engine speed, fuel injection quantity, DPF differential pressure, and fault codes sent by the ECU to the vehicle protection device; and protection signals such as engine surface temperature, exhaust temperature, and emergency stop commands sent by the vehicle protection device to the ECU.

[0030] Example 2: Specific Implementation of ECU Software Control Strategy The control strategy of this embodiment is fully solidified in the Flash memory of the ECU, mainly including three core functional modules: high-altitude adaptation and temperature protection control, DPF regeneration management control, and EGR closed-loop and open-loop composite control. The specific implementation logics of each module are as follows: High-altitude adaptation and temperature protection control logic: This module is used to solve the problems of inaccurate high-altitude fuel quantity control and excessive surface temperature caused by the failure of the on-board atmospheric pressure sensor of the ECU. The specific implementation steps are as follows: Estimation of ambient atmospheric pressure: When the vehicle is powered on (Key-On) but the engine has not entered the starting state (crankshaft speed < 100 rpm), there is no air flow in the intake manifold, and the pressure is completely balanced with the outside atmospheric pressure. At this time, the ECU reads the pressure value of the intake air temperature and pressure sensor, marks it as the current ambient atmospheric pressure value P_atm, and writes it into the non-volatile memory (EEPROM) of the ECU. This value remains unchanged during this vehicle power-on cycle until it is recalibrated during the next power-on.

[0031] Calculation of altitude and maximum fuel injection quantity: The ECU calculates the current altitude according to the formula altitude: H = 44330×[1 - (P_atm / 101.325)^(1 / 5.255)]. During the engine operation, the ECU queries the pre-stored two-dimensional Map of "altitude - maximum cycle fuel injection quantity" in real time. This Map is calibrated through bench tests and covers the altitude range of 0 - 4500 m. As the altitude increases (P_atm decreases), the ECU automatically reduces the maximum cycle fuel injection quantity limit, and controls the air-fuel ratio within the safe range of 16:1 - 18:1 to prevent the exhaust temperature from rising sharply due to too small air-fuel ratio.

[0032] Linkage protection of engine surface temperature: The vehicle protection device collects the highest surface temperature T_surf of the engine in real time through surface temperature sensors installed at key parts such as the engine cylinder head, exhaust pipe, and turbocharger housing, and sends it to the ECU through the CAN bus at a frequency of 10 Hz. The ECU internally presets two levels of temperature thresholds: warning threshold T_warn = 150 °C, shutdown threshold T_stop = 160 °C.

[0033] When T_surf < T_warn, the ECU allows the engine to output full power; When T_warn ≤ T_surf < T_stop, the ECU executes a power degradation strategy, reducing 2% of the rated power for every 1 °C increase, and at the same time sending a warning signal to the vehicle protection device through the CAN bus to trigger a yellow audible and visual alarm; When T_surf≥T_stop, the ECU immediately cuts off the power supply to the injectors, performs an automatic fuel cut-off and shutdown operation, sends a red fault alarm signal, and stores the fault code P0128 (overheated surface) in the fault memory.

[0034] DPF Regeneration Management Control Logic: Given the special nature of the flammable and explosive environment in underground mines, this system has restructured the DPF regeneration strategy for safety. The specific implementation steps are as follows: Passive regeneration function disabled: The passive regeneration function of DPF is permanently disabled at the ECU software level, which prevents the engine from automatically increasing the exhaust temperature by adjusting the fuel injection timing during normal operation to regenerate and avoid the risk of gas explosion caused by uncontrollable increase in exhaust temperature.

[0035] Active regeneration trigger judgment: The ECU reads the differential pressure sensor values ​​ΔP at the front and rear ends of the DPF in real time at a frequency of 1Hz. The ECU has a pre-stored "DPF carbon load-differential pressure" correspondence table calibrated by bench test. When ΔP≥15kPa (corresponding to a carbon load of about 25g / L), the ECU determines that the DPF needs to be regenerated.

[0036] Regeneration Reminder and Safety Confirmation: The ECU sends a "Regeneration Request" signal to the vehicle protection device via the CAN bus. Upon receiving the signal, the vehicle protection device displays a message on the screen stating "Please move the vehicle to a safe location for DPF regeneration," and simultaneously triggers an audible and visual alarm (intermittent buzzer and flashing indicator light). The driver must drive the vehicle to a designated regeneration area in the well that is free of flammable materials and has good ventilation, and press the "Regeneration Confirmation" button on the vehicle protection device before the ECU will proceed with the regeneration operation.

[0037] Active regeneration: The ECU controls the injectors to perform post-injection during the exhaust stroke, injecting fuel into the exhaust manifold. The fuel oxidizes and releases heat in the DOC (Diesel Oxide Charge), raising the exhaust temperature to 550-600°C, continuously burning the particulate matter trapped in the DPF (Diesel Particulate Filter). During regeneration, the ECU monitors the DOC outlet temperature in real time. If the temperature exceeds 650°C, post-injection is immediately stopped to prevent overheating and damage to the DPF. After regeneration is complete (ΔP ≤ 5 kPa), the ECU automatically exits the regeneration mode, restoring normal engine operation.

[0038] EGR closed-loop and open-loop combined control logic: Since there are no automotive-grade air flow sensors (MAF) with mining safety certification, this system uses the velocity-density method to replace direct flow measurement to achieve precise EGR control. The specific implementation steps are as follows: Total intake volume calculation: Using the intake pressure P_intake collected by the intake manifold pressure sensor and the intake temperature T_intake collected by the intake temperature sensor, combined with the engine speed n, the total mass of the air-fuel mixture entering the cylinder (fresh air + EGR exhaust gas) is calculated using the velocity-density method. The calculation formula is: m_total=(P_intake×V_d×η_v) / (R×T_intake×n / 2) where V_d is the engine displacement, η_v is the volumetric efficiency, and R is the gas constant.

[0039] Fresh air quality estimation: Based on the volumetric efficiency model calibrated by engine bench tests, combined with intake pressure, temperature and speed, the fresh air quality m_air entering the engine is estimated, replacing the function of the original MAF sensor.

[0040] EGR closed-loop control: Based on the current engine operating conditions, the target EGR rate is determined, and the target EGR exhaust gas mass flow rate m_egr_target = m_total × target EGR rate is calculated. The ECU adjusts the opening of the EGR valve through a PID algorithm, so that the actual EGR exhaust gas mass flow rate tracks the target value, thus achieving closed-loop control.

[0041] High-altitude open-loop correction: A basic open-loop map of the EGR valve is established based on engine speed n and cyclic injection quantity q. An atmospheric pressure correction coefficient K_alt is introduced, which is inversely proportional to the ambient atmospheric pressure P_atm. Calibrated through bench tests, K_alt is set to: K_alt = 101.325 / P_atm. The final target EGR valve opening = basic open-loop opening × K_alt. This correction strategy ensures that the EGR valve opening is reasonably compensated under high-altitude, low-pressure conditions, maintaining the optimal exhaust gas recirculation rate and guaranteeing stable emission performance.

[0042] Example 3: Complete Workflow of the Control System This embodiment describes in detail the complete working process of the control system of the present invention from startup to shutdown: Initialization phase: The driver turns on the vehicle's main power switch, and the ECU powers on and performs a self-test. After the self-test passes, with the engine off, the ECU reads the intake air pressure sensor value as the current ambient atmospheric pressure value P_atm, stores it in non-volatile memory, and completes the altitude parameter initialization.

[0043] Normal operation phase: After the engine starts, the ECU calculates the current altitude based on P_atm and limits the maximum amount of fuel injected in a cycle. The total intake air volume and fresh air mass are calculated using the velocity-density method, and the opening of the EGR valve is controlled by a closed-loop + open-loop composite strategy to ensure that emissions meet standards. The vehicle protection device monitors the engine surface temperature in real time and transmits it to the ECU via the CAN bus. The ECU then dynamically adjusts the engine output power based on the temperature value. The ECU monitors the DPF differential pressure in real time. When the regeneration threshold is reached, it sends a regeneration request and alerts the driver.

[0044] Anomaly protection phase: If the engine surface temperature reaches the warning threshold, the ECU will automatically reduce power and trigger an alarm. If the surface temperature reaches the shutdown threshold or a serious sensor malfunction occurs, the ECU will immediately execute an oil cut-off shutdown. If an abnormal temperature occurs during DPF regeneration, the ECU will immediately terminate the regeneration process to prevent equipment damage.

[0045] Shutdown phase: The driver turns off the ignition switch, the ECU saves all data from this operation (including fault codes, DPF carbon load, cumulative running time, etc.), and then enters sleep mode.

[0046] The following points should be noted in this article: 1. The accompanying drawings of the embodiments of the present invention only involve the structures involved in the embodiments of the present invention; other structures can refer to general designs.

[0047] 2. Where there is no conflict, the embodiments of the present invention and the features thereof can be combined with each other to obtain new embodiments. The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A control method for non-road Stage IV compliant anti-knock diesel engine, based on non-road Stage IV diesel original engine without SCR system and with EGR+DOC+DPF emission technology route, characterized in that, This includes hardware adaptation steps and software control steps: S1: Hardware adaptation: Replace the corresponding original parts with sensors and actuators that have obtained safety mark certification for mining products, remove the original DPF differential pressure sensor and replace it with an explosion-proof or intrinsically safe differential pressure sensor with safety mark certification, and remove the original ambient temperature sensor. Replace the original turbocharger with a water-cooled turbocharger and match a wet exhaust system at the exhaust end. The ECU of the fuel injection electronic control unit is installed in an explosion-proof cavity that conforms to the GB / T3836-2021 standard; S2: When the ECU is powered on but the engine is not started, it reads the value of the intake air pressure sensor as the current ambient atmospheric pressure value and stores it. S3: During engine operation, the ECU calculates the current altitude based on the ambient atmospheric pressure value and queries the preset altitude-maximum fuel injection quantity mapping map to limit the maximum cycle fuel injection quantity. Simultaneously, the engine surface temperature data transmitted in real time by the vehicle protection device is received via the CAN bus, and the engine output power is dynamically adjusted according to the surface temperature. If the temperature exceeds the limit, the engine will shut down and cut off the fuel supply. S4: Disable DPF passive regeneration function, retain only active regeneration function; The ECU reads the value of the DPF differential pressure sensor in real time. When the preset regeneration threshold is reached, it sends a regeneration request to the vehicle protection device through the CAN bus, triggering an audible and visual alarm to prompt the driver to move to a safe location before performing active regeneration. S5: The total mass of the air-fuel mixture entering the cylinder and the mass of fresh air are calculated using the velocity-density method, replacing the original air flow sensor to achieve EGR closed-loop control; Simultaneously, an open-loop EGR control strategy based on engine speed and cyclic fuel injection quantity is established, and an atmospheric pressure correction coefficient is introduced to correct the open-loop opening of the EGR valve.

2. A control system device for an explosion-proof diesel engine suitable for Stage IV emissions, used to implement the control method described in claim 1, comprising an explosion-proof diesel engine body, a fuel injection electronic control device, a vehicle protection device, an exhaust aftertreatment system, and a sensor actuator assembly, characterized in that: The explosion-proof diesel engine body is a non-road China IV diesel engine that adopts the EGR+DOC+DPF emission technology route and does not contain an SCR system. Its turbocharger is a water-cooled turbocharger and a wet exhaust system is matched at the exhaust end. The ECU of the fuel injection electronic control device is installed in an explosion-proof cavity that conforms to the GB / T3836-2021 standard. The ECU is bidirectionally connected to the vehicle protection device via a CAN bus. The crankshaft position sensor, camshaft position sensor, intake air temperature and pressure sensor, coolant temperature sensor, oil pressure sensor, accelerator pedal position sensor, injector, oil pump metering valve, EGR valve, and DOC temperature sensor in the sensor actuator assembly are all explosion-proof or intrinsically safe products that have obtained mining product safety mark certification. Replace the original DPF differential pressure sensor with a safety-certified explosion-proof or intrinsically safe differential pressure sensor, and remove the original ambient temperature sensor; The ECU is embedded with a high-altitude adaptive and temperature protection module, a DPF regeneration management module, and an EGR composite control module, which are used to perform high-altitude oil quantity limitation and surface temperature linkage protection, DPF active regeneration control, and EGR closed-loop and open-loop composite control, respectively.

3. The control method for anti-knock diesel engine applicable to the fourth stage emission according to claim 1, characterized in that, In step S2, when the ECU is powered on and the engine is not started, the pressure inside the intake manifold is balanced with the external atmospheric pressure. The ECU reads the value of the intake pressure sensor and marks it as the current ambient atmospheric pressure value. This value is stored in a non-volatile memory to replace the data of the onboard atmospheric pressure sensor of the ECU.

4. The control method for anti-knock diesel engine applicable to the fourth stage emission according to claim 1, characterized in that, In step S3, the ECU has preset surface temperature warning threshold and shutdown threshold. When the engine surface temperature is greater than or equal to the warning threshold, the ECU actively reduces the engine output power. When the engine surface temperature is greater than or equal to the shutdown threshold, the ECU performs an automatic fuel cut-off shutdown operation and sends a fault code to the vehicle protection device via the CAN bus, triggering an audible and visual alarm.

5. The control method for anti-knock diesel engine applicable to the fourth stage emission according to claim 1, characterized in that, In step S4, the ECU has a pre-stored differential pressure regeneration threshold corresponding to the carbon load of the DPF; when the value of the DPF differential pressure sensor is greater than or equal to the regeneration threshold, the ECU determines that regeneration is required; after the driver confirms that the environment is safe, the ECU controls the fuel injector to perform post-injection to increase the exhaust temperature and execute DPF active regeneration to burn off particulate matter.

6. The control method for anti-knock diesel engine applicable to the fourth stage emission according to claim 1, characterized in that, In step S5, the total air-fuel mixture mass is calculated using the intake manifold pressure, intake air temperature, and engine speed via the velocity-density method; the fresh air mass is estimated based on the velocity-density method combined with the volumetric efficiency model; and the EGR closed-loop control is achieved by adjusting the EGR valve opening using a PID algorithm. The final target opening degree of EGR open-loop control is the product of the basic open-loop opening degree and the atmospheric pressure correction coefficient, which is determined based on the mapping spectrum of engine speed and cyclic fuel injection quantity.

7. The control system apparatus for anti-knock diesel engine adapted for phase IV emission according to claim 2 wherein, The exhaust aftertreatment system includes, in sequence, an EGR valve, a DOC oxidation catalyst, and a DPF particulate filter. The front and rear ends of the DPF particulate filter are connected to the safety-certified differential pressure sensor, respectively.

8. The explosion-proof diesel engine control system device suitable for Stage IV emissions according to claim 2, characterized in that, The high-altitude adaptive and temperature protection module is used to read the intake pressure sensor value as the ambient atmospheric pressure value and store it when the ECU is powered on and the engine is not started; calculate the altitude based on the ambient atmospheric pressure value, query the altitude-maximum fuel injection quantity mapping map to limit the maximum cycle fuel injection quantity; receive engine surface temperature data transmitted by the vehicle protection device, and dynamically adjust the engine output power or perform fuel cut-off shutdown according to the preset warning threshold and shutdown threshold.

9. The explosion-proof diesel engine control system device suitable for Stage IV emissions according to claim 2, characterized in that, The DPF regeneration management module is used to software-disable the passive regeneration function of DPF; it reads the value of the DPF differential pressure sensor in real time and compares it with the preset regeneration threshold. When the threshold is reached, it sends a regeneration request to the vehicle protection device through the CAN bus; after the driver confirms safety, it controls the injector to perform a post-injection operation to complete the active regeneration of DPF.

10. The explosion-proof diesel engine control system device suitable for Stage IV emissions according to claim 2, characterized in that, The EGR composite control module is used to calculate the total mixture mass and fresh air mass using the velocity-density method, replacing the air flow sensor to achieve EGR closed-loop control; it establishes an EGR open-loop control strategy based on engine speed and cyclic fuel injection quantity, and introduces an atmospheric pressure correction coefficient to compensate for altitude of the EGR valve open-loop opening.

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