Diesel engine combustion cooperative control system and method based on SCR operation state

Abstract

The invention discloses a diesel engine combustion cooperative control system and method based on an SCR operation state, and the method comprises the steps: constructing a residual ammonia estimation model through real-time detection of operation parameters such as engine rotation speed, load, exhaust temperature, exhaust flow and the like and NOx concentration in SCR upstream exhaust gas, and carrying out the online estimation of a residual ammonia state possibly existing at the SCR downstream, when the residual ammonia state quantity exceeds a residual ammonia threshold value, reverse constraint correction is applied to the urea injection quantity, and a combustion side coordinated regulation mechanism is synchronously triggered; and on the basis of the discrete state space model containing the residual ammonia state variable, unified closed-loop adjustment is carried out on the urea injection amount, the EGR proportion, the hydrogen supply amount and the diesel injection amount. According to the method, the perception capability and control robustness of the system on the ammonia supply allowance change under the transient working condition and the load fluctuation condition are improved.

Description

Technical Field

[0001] This invention relates to the field of coordinated emission control and combustion control technology for internal combustion engines, and particularly to a combustion control system and method suitable for heavy-duty truck diesel engines equipped with Selective Catalytic Reduction (SCR) devices. Specifically, this invention relates to a control architecture that incorporates the operating status information of the SCR denitrification system into the engine combustion control loop, estimates the residual ammonia state downstream of the SCR system using a model, and uses the estimation result as a combustion control input variable and a system state variable to coordinately constrain and adjust the urea injection quantity, exhaust gas recirculation ratio, hydrogen supply quantity, and diesel injection quantity, thereby achieving coordinated optimization of denitrification efficiency, residual ammonia state, and combustion stability. Background Technology

[0002] Heavy-duty trucks generally use diesel engines as their power source. To meet increasingly stringent nitrogen oxide (NOx) emission regulations, existing vehicles typically incorporate selective catalytic reduction (SCR) devices in their exhaust systems. This involves injecting urea solution into the exhaust gas, causing it to pyrolyze and generate ammonia, which then reduces NOx on the catalyst surface.

[0003] In actual operation, to ensure that the SCR system maintains high denitrification efficiency under fluctuating operating conditions, a urea injection control strategy with ammonia supply margin is typically required. While this strategy can improve NOx conversion, under certain operating conditions, it can lead to unreacted residual ammonia in the downstream exhaust gas, posing a risk of ammonia slip. Existing technologies often suppress ammonia slip by adding ammonia oxidation catalysts or optimizing injection strategies, but these solutions tend to increase the complexity and cost of the exhaust aftertreatment system and are difficult to balance denitrification efficiency and system stability across all operating conditions.

[0004] On the other hand, diesel engines are prone to problems such as increased ignition delay and combustion instability under lean combustion and low load conditions. Existing studies have attempted to improve combustion stability through exhaust gas recirculation (EGR) or the introduction of hydrogen, but these solutions usually exist as independent control strategies and have not yet formed a system-level synergy with the operation of the SCR denitrification system.

[0005] From a system-wide perspective, the ammonia supply margin state formed by the SCR system during denitrification is objectively coupled with engine combustion control. However, existing technologies have not yet developed a technical solution that incorporates SCR operating status information into the engine combustion control loop and achieves coordinated optimization of denitrification efficiency, residual ammonia state, and combustion stability through control logic. Summary of the Invention

[0006] To address the issues of insufficient combustion stability and low efficiency at low loads in existing heavy-duty diesel engines under stringent emission regulations, as well as the potential risk of residual ammonia in SCR systems employing ammonia margin supply strategies without system-level synergistic utilization, the present invention aims to provide a diesel engine combustion synergistic control system and method based on SCR operating status.

[0007] This invention, while ensuring that the SCR denitrification efficiency always meets emission regulations, constructs a residual ammonia estimation model by real-time monitoring of operating parameters such as engine speed, load, exhaust temperature, and exhaust flow, as well as the NOx and CO concentrations in the exhaust gas upstream of the SCR. This model estimates the potential residual ammonia state downstream of the SCR online and introduces this residual ammonia state quantity as a state variable that can be incorporated into the combustion control loop for ECU control decisions. The residual ammonia state quantity is obtained online from the exhaust gas information and operating parameters upstream of the SCR using the residual ammonia estimation model, and it does not depend on the ammonia sensor input downstream of the SCR. The ECU compares the estimated residual ammonia state quantity with a residual ammonia threshold that varies with operating conditions. Without compromising the SCR denitrification efficiency constraint, it applies a reverse constraint correction to the urea injection quantity and simultaneously triggers a combustion-side collaborative adjustment mechanism. This mechanism coordinates and adjusts the exhaust gas recirculation (EGR) ratio, the hydrogen supply from the onboard hydrogen production unit, and the diesel injection quantity, allowing the recirculated exhaust gas, hydrogen, and fresh air to participate in the intake and combustion process. This enables the combustion-side absorption of the SCR ammonia supply margin, suppressing the risk of residual ammonia accumulation downstream of the SCR. Simultaneously, the ECU constructs a joint state vector from combustion characteristics such as residual ammonia state, engine speed and load, combustion phase CA50, combustion stability index COVIMEP, and ignition delay time ID. Based on a discrete state-space model or model predictive control framework that includes residual ammonia state variables, it implements unified closed-loop regulation of urea injection quantity, EGR ratio, hydrogen supply quantity, and diesel injection quantity. This ensures that the SCR denitrification efficiency state, the downstream residual ammonia state of the SCR, and the engine combustion stability state converge collaboratively to a preset target range within the same control loop. Thus, without altering the existing basic SCR structure, it achieves cross-system introduction of SCR operating state information from the emission system side to the combustion control side. By having recirculated exhaust gas and hydrogen participate in the combustion process in coordination with the diesel injection strategy, it improves the engine's ignition reliability and combustion stability under lean combustion and partial load conditions, enhances overall engine energy utilization efficiency, and balances emission compliance and system reliability.

[0008] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0009] A diesel engine combustion co-control system based on SCR operation includes a cylinder and an ECU, wherein a cylinder pressure sensor is provided on the cylinder;

[0010] An air filter, a compressor, and an intercooler are sequentially installed on the intake pipe of the cylinder along the direction of fresh air flow.

[0011] Along the exhaust direction, the exhaust pipe of the cylinder is equipped with an exhaust gas composition analysis unit and an SCR after-treatment system in sequence.

[0012] An EGR valve is installed between the intake pipe and the exhaust pipe;

[0013] An air intake pipe near the cylinder is equipped with an air jet valve, which is connected in sequence to a hydrogen pressure regulating device, a hydrogen metering device, and a hydrogen generator.

[0014] The cylinder is equipped with a fuel injector, and a diesel filter and a fuel pump are sequentially installed on the pipeline connecting the fuel injector and the diesel tank.

[0015] The ECU communicates with the jet valve, injector, EGR valve, exhaust gas composition analysis unit, and cylinder pressure sensor.

[0016] The above technical solution also includes a tail gas combustible component detection unit located at the rear of the SCR aftertreatment system along the exhaust gas flow direction.

[0017] The above technical solution also includes an emission recovery and coordination treatment unit located behind the exhaust gas combustible component detection unit along the exhaust gas flow direction.

[0018] A diesel engine combustion coordination control method based on SCR operation:

[0019] The exhaust gas composition analysis unit collects the NOx concentration in the exhaust gas upstream of the SCR in real time, and simultaneously collects the exhaust temperature, exhaust pressure, engine speed and load, and inputs the signals into the ECU;

[0020] The ECU constructs a residual ammonia estimation model based on upstream NOx concentration, urea injection quantity, exhaust flow rate, exhaust temperature, and catalyst activity decay factor of the SCR, to estimate the residual ammonia state quantity that may exist downstream of the SCR. Online estimation is performed, and the residual ammonia state is corrected by incorporating the dynamic state of SCR ammonia storage, resulting in an estimated value of residual ammonia considering the hysteresis effect of SCR ammonia storage and release. After being filtered or processed by a state observer, it becomes the residual ammonia state quantity entering the combustion control loop. ;

[0021] The residual ammonia state quantity Residual ammonia threshold varying with engine speed and load _th In comparison, when the residual ammonia state exceeds the corresponding threshold, without compromising the SCR denitrification efficiency constraint, a reverse constraint correction is applied to the urea injection quantity, and a combustion-side coordinated adjustment request quantity for absorbing the SCR ammonia supply margin is generated simultaneously; based on the combustion-side coordinated adjustment request quantity, the ECU adjusts the exhaust gas recirculation ratio, hydrogen supply quantity and diesel injection quantity, so that the recirculated exhaust gas, hydrogen and fresh air participate together in the intake and combustion process;

[0022] The ECU further measures the residual ammonia state. The engine speed and load, combustion phase CA50, combustion stability index COVIMEP, ignition delay time ID, exhaust temperature, and exhaust flow rate together constitute a joint state vector. Based on a discrete state-space model or model predictive control that includes residual ammonia state variables, a unified closed-loop regulation is implemented on the urea injection quantity, exhaust gas recirculation ratio, hydrogen supply ratio, and diesel injection quantity. This ensures that the SCR denitrification efficiency state, the SCR downstream residual ammonia state, and the engine combustion stability state converge collaboratively to the preset target range within the same control loop.

[0023] Furthermore, the residual ammonia estimation model is as follows:

[0024]

[0025] in, The concentration of nitrogen oxides upstream of the SCR. This refers to the urea injection volume. For exhaust flow rate, The exhaust temperature, This is the catalyst activity attenuation factor.

[0026] Furthermore, the estimated residual ammonia value considering the hysteresis effect of SCR ammonia storage and release is obtained as follows:

[0027]

[0028] Among them, ammonia supply margin Theoretical ammonia demand for SCR , This is a state variable for ammonia storage.

[0029] Furthermore, the ammonia storage state variable Update as follows:

[0030]

[0031] in, This represents the ammonia adsorption efficiency coefficient. This is the ammonia release attenuation coefficient.

[0032] Furthermore, the application of reverse constraint correction to the urea injection quantity specifically includes:

[0033] Based on the residual ammonia exceeding the limit ( According to the proportional factor Adjust the urea injection rate by decreasing the amount of urea injected:

[0034]

[0035] in, The urea injection rate is set according to the closed-loop denitrification control results based on the NOx concentration upstream of the SCR.

[0036] The combustion-side coordinated adjustment request for absorbing the SCR ammonia supply margin is generated synchronously, specifically as follows:

[0037]

[0038]

[0039]

[0040] Wherein, ΔEGR is the exhaust gas recirculation ratio adjustment request, ΔH2 is the hydrogen supply adjustment request, and ΔDiesel is the diesel injection quantity adjustment request. , , , All of these are calibration coefficients.

[0041] Furthermore, the unified closed-loop regulation adopts the following joint state feedback law that includes residual ammonia state variables:

[0042]

[0043] in, K represents the state feedback gain matrix, where K is the feedforward control variable based on engine speed and load. Let be the system state vector. Let J be the system target state vector, and J be the combustion stability error feedback gain matrix. , , , , , , These are the target values ​​for CA50, COVIMEP, and ID, respectively.

[0044] Furthermore, before outputting the urea injection quantity, exhaust gas recirculation ratio, hydrogen supply ratio, and diesel injection quantity, the ECU applies amplitude constraints and rate of change constraints to each control quantity and performs smoothing processing.

[0045] Compared with the prior art, the present invention has at least the following beneficial effects:

[0046] (1) Under the premise of ensuring that the SCR denitrification efficiency always meets the emission regulations, based only on the operating parameters such as the NOx concentration, urea injection amount, exhaust temperature and exhaust flow rate upstream of SCR, an online estimation model for the residual ammonia state downstream of SCR is constructed, and the residual ammonia state quantity is used as a state variable that can enter the combustion control loop to participate in the ECU control decision, thereby improving the system's ability to perceive changes in ammonia supply margin and control robustness under transient operating conditions and load fluctuations.

[0047] (2) By comparing the estimated residual ammonia state quantity with the residual ammonia threshold that varies with engine speed and load, the urea injection quantity is modified by applying a reverse constraint without destroying the SCR denitrification efficiency constraint, and the combustion side coordinated adjustment mechanism is triggered simultaneously to realize the combustion side absorption of the SCR ammonia supply margin, effectively suppressing the accumulation of residual ammonia and the risk of ammonia escape downstream of SCR, and avoiding the problem of excessive ammonia supply caused by the traditional SCR relying solely on urea injection closed-loop control from the control level.

[0048] (3) By introducing controlled exhaust gas recirculation (EGR) and hydrogen generated by the on-board hydrogen production device, the recirculated exhaust gas, hydrogen and fresh air participate in the intake and combustion process together, and cooperate with the diesel injection strategy to coordinate the boundary conditions of the combustion side under the constraint of residual ammonia state, effectively improving the ignition reliability and combustion stability under lean combustion and partial load conditions, reducing combustion cycle fluctuation (COVIMEP) and shortening the ignition delay time;

[0049] (4) By combining the residual ammonia state quantity, engine speed and load, combustion phase CA50, combustion stability index COVIMEP and ignition delay time ID into a joint state vector, and based on a discrete state space model or model predictive control framework containing residual ammonia state variables, a unified closed-loop regulation is implemented on urea injection quantity, EGR ratio, hydrogen supply quantity and diesel injection quantity, so that the SCR denitrification efficiency state, the SCR downstream residual ammonia state and the engine combustion stability state converge to the preset target range in the same control loop, avoiding the mutual independence and conflict regulation between SCR denitrification control and engine combustion control.

[0050] (5) Without changing the basic structure of the existing SCR aftertreatment system, by simply adding an upstream exhaust gas component sensing unit, an on-board hydrogen production device and corresponding control strategies, the cross-system introduction of SCR operating status information from the emission system side to the combustion control side can be realized, and the functional-level collaborative optimization of the combustion process and emission process can be completed, avoiding a significant increase in the complexity of the whole vehicle system and the cost of hardware modification.

[0051] (6) By implementing zoned coordinated control of EGR ratio, hydrogen supply ratio and diesel injection quantity in the low load, medium load and high load operating conditions, the operation stability, combustion efficiency and economy of heavy-duty diesel engine under low load and partial load conditions are improved while ensuring emission compliance. It has good engineering practical value and application prospects. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the diesel engine combustion coordination control system based on SCR operation state according to the present invention;

[0053] In the diagram: 1. Hydrogen generator; 2. Hydrogen metering device; 3. Hydrogen pressure regulating device; 4. Injection valve; 5. Diesel tank; 6. Diesel filter; 7. Fuel pump; 8. Intercooler; 9. Air filter; 10. Compressor; 11. Exhaust gas combustible component detection unit; 12. Emission recovery and treatment unit; 13. EGR valve; 14. SCR aftertreatment system; 15. Exhaust gas composition analysis unit; 16. Sensor signal interface; 17. ECU (Electronic Control Unit); 18. Cylinder pressure sensor; 19. Fuel injector; 20. Cylinder. Detailed Implementation

[0054] The following description, in conjunction with the accompanying drawings, illustrates a preferred embodiment of the present invention based on the SCR-based diesel engine hydrogen and exhaust gas co-combustion control system structure. This embodiment is merely for explaining the technical concept of the invention and does not constitute a limitation on the scope of protection of the invention. This embodiment uses diesel as the primary fuel and, while ensuring emission compliance, achieves co-combustion control and improved energy utilization efficiency with the assistance of hydrogen and recirculated exhaust gas through SCR denitrification system operation status sensing, residual ammonia state model estimation, and coordinated control of exhaust gas recirculation and on-board hydrogen production.

[0055] I. System Overall Structure

[0056] like Figure 1 As shown, the SCR-based diesel engine hydrogen and exhaust gas co-combustion control system of the present invention includes: a hydrogen generator 1, a hydrogen metering device 2, a hydrogen pressure regulating device 3, an injection valve 4, a diesel tank 5, a diesel filter 6, a fuel pump 7, an intercooler 8, an air filter 9, a compressor 10, an exhaust gas combustible component detection unit 11, an emission recovery and coordination treatment unit 12, an EGR valve 13, an SCR aftertreatment system 14, an exhaust gas component analysis unit 15, a sensor signal interface 16 (located on the ECU 17), an ECU 17, a cylinder pressure sensor 18, a fuel injector 19, and a cylinder 20.

[0057] Fresh air is filtered by air filter 9 and then enters compressor 10 for pressurization. After being cooled by intercooler 8, the compressed air enters the intake manifold and is delivered to cylinder 20.

[0058] Diesel fuel is filtered by diesel filter 6 from diesel tank 5, then pressurized and delivered to injector 19 by fuel pump 7. Under the control of ECU 17, it is injected into cylinder 20 for combustion according to the set injection timing and quantity. ECU 17 serves as the central control unit for the entire engine, receiving operating signals from various sensors and coordinating the control of injector 19, EGR valve 13, jet valve 4, and urea injector (located in SCR aftertreatment system 14).

[0059] After the exhaust gas generated by engine combustion enters the exhaust pipe, it first passes through the exhaust gas composition analysis unit 15, and then enters the SCR aftertreatment system 14 for denitrification reaction. The exhaust gas composition analysis unit 15 is used to collect the NOx concentration and CO concentration in the exhaust gas upstream of the SCR in real time, and send the detection signal to the ECU 17 for SCR denitrification control and residual ammonia status estimation.

[0060] Under the regulation of EGR valve 13, part of the exhaust gas treated by SCR is introduced into the intake system to form exhaust gas recirculation, while the remaining exhaust gas continues to flow along the exhaust pipe and enters the emission recovery and coordination treatment unit 12 after being monitored by the exhaust gas combustible component detection unit 11, and is then discharged in compliance with standards. Among them, the exhaust gas combustible component detection unit 11 is used to monitor the content of combustible components such as hydrogen, carbon monoxide and hydrocarbons (HC) in the exhaust gas, as an auxiliary monitoring signal for the operating status of the exhaust system; the emission recovery and coordination treatment unit 12 is used to adsorb, oxidize or capture residual ammonia and combustible pollutants, as a safety fallback unit of the emission system.

[0061] The hydrogen generator 1 is connected to the vehicle power system and is used to produce hydrogen through water electrolysis, on-board reforming reaction, or hydrogen release from metal hydrides. The generated hydrogen is regulated by the hydrogen metering device 2 and the hydrogen pressure regulating device 3, and then enters the intake manifold through the jet valve 4 controlled by the ECU 17. After mixing with the recirculated exhaust gas and fresh air, it enters the cylinder 20.

[0062] The cylinder pressure sensor 18 is mounted on the cylinder head to monitor the cylinder pressure during combustion and transmits it to the ECU 17 to determine the combustion stage and to calculate the combustion phase CA50, the mean effective pressure variation coefficient COVIMEP, and the ignition delay time ID.

[0063] It should be noted that in some embodiments, the exhaust combustible component detection unit 11 and / or emission recovery coordination processing unit 12 may be omitted. The above units are used to provide exhaust safety redundancy protection, and their presence or absence does not affect the control main line of "SCR operating status information entering the combustion control loop".

[0064] The above structures together constitute the physical and signal channel basis for realizing "SCR operating status information entering the combustion control loop", providing actuator and sensor support for subsequent residual ammonia state estimation, urea injection reverse constraint and coordinated combustion control.

[0065] II. Structure and Function of the SCR Upstream Exhaust Gas Composition Sensing Unit

[0066] This unit serves as the starting point of the SCR operating state sensing link, providing upstream boundary condition inputs for the residual ammonia state estimation model and acting as an information source for the SCR operating state to enter the combustion control loop. The exhaust gas composition analysis unit 15 is located in the exhaust pipe section upstream of the SCR aftertreatment system 14. The exhaust gas composition analysis unit 15 includes: an integrated gas sampling probe, a heated sampling pipeline, a particulate filter assembly, and a gas sensing module.

[0067] The gas sensing module includes at least a NOx sensor unit and a CO sensor unit, and optionally a hydrocarbon sensor unit;

[0068] The gas sampling probe is inserted into the middle of the main exhaust channel to stably collect representative exhaust gas samples under high temperature and high flow rate conditions.

[0069] The heated sampling pipeline is used to prevent water vapor condensation.

[0070] The particulate filter assembly is used to remove smoke and particulate matter to avoid contaminating the sensor's sensitive elements.

[0071] The exhaust gas composition analysis unit 15 is electrically connected to the ECU 17 through the sensor signal interface 16, and sends the NOx concentration, CO concentration and optional HC concentration signals upstream of the SCR to the ECU 17 for theoretical ammonia demand calculation, residual ammonia state estimation and combustion coordination control decision-making; among them, the CO concentration signal can be used to correct and identify incomplete combustion conditions and assist in safety constraint judgment.

[0072] III. Structure and Function of the Safety Monitoring Unit for Combustible Components in Downstream SCR Exhaust Gas

[0073] The exhaust gas combustible component detection unit 11 is located downstream of the SCR aftertreatment system 14 in the exhaust pipe. The exhaust gas combustible component detection unit 11 includes a combustible gas sensor module, a temperature compensation module, and a signal conditioning module.

[0074] The combustible gas sensor module can be a thermal conductivity sensor, a semiconductor sensor, or an infrared absorption sensor, used to detect the volume fraction of hydrogen, carbon monoxide, and hydrocarbon combustible components in the exhaust gas.

[0075] The output signal of the exhaust combustible component detection unit 11 serves as an auxiliary monitoring quantity for the operating status of the exhaust system. It is used to determine abnormal operating conditions, incomplete combustion conditions, or excessive hydrogen co-firing conditions of the SCR aftertreatment system 14, and can also serve as a safety constraint input signal for the ECU 17. The safety constraint input signal is used to apply upper limit constraints or reduction controls to the hydrogen supply, exhaust gas recirculation ratio, and diesel injection quantity when the concentration of combustible components in the exhaust gas exceeds a preset safety threshold, in order to reduce the risk of exhaust system backfire, catalyst overheating, or ammonia escape.

[0076] The output signal of the exhaust combustible component detection unit 11 does not participate in the optimization solution of the main combustion control quantity, but participates in the control quantity limiting and reduction logic as a safety constraint variable, which is used to apply protective constraints to the hydrogen supply, exhaust gas recirculation ratio and diesel injection quantity under abnormal operating conditions.

[0077] IV. Safety backup treatment unit for residual ammonia and combustible pollutants at the end of emission.

[0078] The emission recovery and coordination treatment unit 12 is located at the end of the exhaust gas emission and includes: an ammonia adsorption module, an oxidation catalysis module and a particulate filter module.

[0079] The ammonia adsorption module uses zeolite molecular sieves, activated carbon, or metal oxide materials to physically or chemically adsorb residual ammonia in the exhaust gas.

[0080] The oxidation catalytic module is used to further oxidize combustible pollutants such as CO and HC in the exhaust gas.

[0081] The particle filtration module is used to capture fine particulate matter.

[0082] The emission recovery and coordination unit 12 serves as a safety fallback unit for the emission system. Its operation does not participate in combustion control decisions; it is solely for emission safety assurance. It should be noted that the emission recovery and coordination unit 12 is not a necessary component of the collaborative control method of this invention. Its presence or absence does not affect the main control line of the SCR operating state entering the combustion control loop; it is only used to provide engineering redundancy assurance at the emission and safety levels.

[0083] V. Residual Ammonia State Estimation Method Based on SCR Upstream Exhaust Gas Information

[0084] (I) Definition of Terms and Consistency Explanation of State Quantities

[0085] To facilitate control implementation and ensure consistency of control variables, the following definition is made:

[0086] Residual ammonia estimated value The real-time output of the residual ammonia estimation model is used to characterize the residual ammonia level that may exist downstream of SCR.

[0087] Residual ammonia state quantity :right The filtered / signal shaped state variables are used for control decisions and serve as system state variables in the discrete state-space model.

[0088] Residual ammonia threshold The threshold value that varies with engine speed n and load L is used to determine whether the residual ammonia risk exceeds the limit and trigger coordinated regulation.

[0089] (II) Residual Ammonia Estimation Model

[0090] The residual ammonia state estimation method is used to construct a residual ammonia state variable that can be included in the combustion control loop, based solely on upstream exhaust gas information and operating parameters of the SCR, without the need for a downstream ammonia sensor. In this embodiment, no downstream ammonia sensor is installed.

[0091] ECU17 is based on the nitrogen oxide concentration detected by the exhaust gas composition analysis unit 15 located upstream of the SCR aftertreatment system 14. In conjunction with operating parameters such as urea injection volume, exhaust temperature, exhaust flow rate, and catalyst activity decay factor, a residual ammonia estimation model is established to estimate the residual ammonia state that may exist in the downstream exhaust gas of SCR in real time.

[0092] The residual ammonia estimation model is shown in equation (1):

[0093] (1)

[0094] in, The concentration of nitrogen oxides upstream of the SCR. This refers to the urea injection volume. For exhaust flow rate, The exhaust temperature, This is the catalyst activity attenuation factor.

[0095] The output form of the residual ammonia state can be the residual ammonia concentration downstream of the SCR, the residual ammonia mass flow rate, or an equivalent residual ammonia state quantity that monotonically corresponds to the residual ammonia concentration / mass flow rate; in engineering implementation, one of these can be selected as the control input and state variable according to the sensor configuration and control requirements.

[0096] Specifically, ECU17 performs the following residual ammonia estimation process within each control cycle (e.g., 10-50ms):

[0097] 1) Read the NOx concentration upstream of the SCR from the exhaust gas composition analysis unit 15. ;

[0098] 2) Read the exhaust temperature from the sensor installed on the engine exhaust pipe. With exhaust pressure Exhaust flow rate is estimated based on exhaust manifold pressure and engine speed. ;

[0099] 3) Read the current urea injection quantity from ECU17 ;

[0100] 4) Read the current catalyst activity degradation factor from the SCR aging model or calibration table. .

[0101] ECU17 calculates the theoretical ammonia requirement for SCR based on the above variables: And further calculate the ammonia supply margin: Subsequently, ECU17 based on exhaust temperature Catalyst activity decay factor and ammonia supply margin The form of the downstream residual ammonia estimation model for SCR is modified to obtain: .

[0102] (III) Introduction of the dynamic state of SCR ammonia storage

[0103] In some implementations, ECU17 also introduces internal state variables to characterize the dynamics of ammonia storage and release in the SCR catalyst. This describes the equivalent storage capacity of ammonia adsorbed on the surface and in the pore structure of the catalyst (located in the SCR aftertreatment system 14). The ammonia storage state variable... Update according to the following recursive relationship:

[0104] (2)

[0105] in, This represents the ammonia adsorption efficiency coefficient. The ammonia release attenuation coefficient is denoted by , and both increase with exhaust temperature. With catalyst active factor It dynamically adjusts according to changes. ECU17 adjusts based on current conditions through table lookup or empirical functions. and The value of and Perform online updates. In one implementation, when the exhaust temperature... Within the effective operating temperature range of the SCR catalyst (e.g., 200-450°C) and the catalyst activity factor At higher levels (e.g., 0.7-1.0), the ammonia adsorption efficiency coefficient... Take a larger value range (e.g., 0.3-0.9), ammonia release attenuation coefficient Take the smaller value range (e.g., 0.01-0.15); when the exhaust temperature Lower (e.g., below 180°C) or catalyst activity factor When it decreases (e.g., below 0.6), The value should be reduced accordingly to a smaller range (e.g., 0.05-0.4). The value should be increased accordingly to a larger range (e.g., 0.1-0.6). Through the above dynamic adjustment, the ammonia storage state variable is adjusted. It can adaptively reflect changes in the ammonia storage and release capacity of the catalyst, thereby improving the accuracy of residual ammonia estimation under transient operating conditions and reducing the risk of ammonia escape.

[0106] ECU17 based on the ammonia storage state variable For instantaneous ammonia supply margin Dynamic corrections are performed to obtain the estimated residual ammonia value that takes into account the SCR ammonia storage and release hysteresis effects:

[0107] (3)

[0108] (iv) Model Engineering Implementation and Signal Shaping

[0109] In engineering implementation, the above functions g(·), h(·), (·) Multidimensional calibration lookup table method, empirical function model, recursive identification model or regression model based on neural network / support vector regression can be used.

[0110] ECU17 A first-order low-pass filter is applied to eliminate the effects of exhaust pulsation and measurement noise, yielding the residual ammonia state parameters for control decision-making. The aforementioned As a combustion control input variable and as a system state variable in the discrete state-space model, it participates in joint state feedback control, thereby realizing the cross-system introduction of SCR operating state information from the emission system side to the combustion control side.

[0111] In some implementations, a residual ammonia state observer can be constructed using a Kalman filter or an extended Kalman filter to monitor the residual ammonia state. Alternatively, recursive estimation and filtering can be performed on the relevant states to obtain the residual ammonia state quantities used for control decisions. .

[0112] VI. Minimum Engineering Implementation Method for Introducing SCR Residual Ammonia State into the Combustion Control Loop

[0113] In a specific engineering implementation, the SCR residual ammonia estimation model h(·) adopts a two-dimensional calibration lookup table form, and its input variables are the ammonia supply margin ΔNH3 and the exhaust temperature. The output is the estimated value of residual ammonia. And based on ammonia storage state variables Make modifications to obtain ,in Update recursively according to formula (2). The residual ammonia state variables are obtained after processing with a first-order low-pass filter for control decision-making. The time constant of the first-order low-pass filter is set according to the thermal inertia of the exhaust system and the dynamic characteristics of SCR ammonia storage, and is taken as 0.5–2 s. Residual ammonia threshold. The calibration is performed using a two-dimensional lookup table that varies with engine speed n and load L. The reverse constraint coefficients α1-α4 are either constants or calibrated segmentally according to operating conditions. System matrices A and B are obtained from engine bench step test data through least-squares identification. The ECU control cycle is set to 10-50 ms. This constitutes a deterministic closed-loop control algorithm that can run in real-time on the ECU, used to introduce the residual ammonia state quantity downstream of the SCR into the combustion control loop and achieve coordinated closed-loop regulation of urea injection quantity, exhaust gas recirculation ratio, hydrogen supply quantity, and diesel injection quantity.

[0114] VII. Reverse Constraint Control Method for Urea Injection Based on Residual Ammonia State

[0115] The reverse constraint control method is used to introduce the residual ammonia state quantity downstream of the SCR as a reverse control variable into the urea injection control loop and the combustion control loop, without compromising the SCR denitrification efficiency constraint. In each control cycle, ECU17 will control the residual ammonia state quantity... Residual ammonia threshold varying with operating conditions The comparison is performed, where n is the engine speed and L is the engine load.

[0116] The residual ammonia threshold It can be calibrated by engine speed n and load L, and stored in the ECU calibration area in a two-dimensional / multi-dimensional lookup table format; its calibration basis may include SCR denitrification efficiency boundary, allowable ammonia slip upper limit, and combustion stability / thermal load constraints. In some embodiments, It can also be based on exhaust temperature Catalyst activity decay factor Online corrections are performed to compensate for the impact of catalyst aging and temperature drift on residual ammonia risk.

[0117] In some implementations, the "zone-calibrated operating range" refers to the operating area where, under the premise of meeting the denitrification efficiency constraint, the ammonia supply margin of the SCR is within a controllable range and can be absorbed by changes in the combustion-side boundary conditions; for example, the residual ammonia state quantity Maintain at the threshold Within the range of near or below this threshold, the NOx conversion efficiency of the SCR is ensured to be no less than the preset lower limit.

[0118] When satisfied ≤ At the same time, ECU17 maintains the SCR denitrification priority control mode, and sets the urea injection quantity according to the closed-loop denitrification control results based on the NOx concentration upstream of the SCR. This ensures that the SCR aftertreatment system 14 operates stably in the high conversion rate range of nitrogen oxides.

[0119] When satisfied > At this time, ECU17 enters the residual ammonia suppression mode, applying a reverse constraint on the urea injection quantity without compromising the SCR denitrification efficiency constraint, and simultaneously triggering the combustion-side collaborative adjustment mechanism. The control process includes the following steps:

[0120] 1) Based on the residual ammonia exceeding the limit ( According to the proportional factor Adjust the urea injection rate by decreasing the amount of urea injected:

[0121] (4)

[0122] in, The urea injection rate is set according to the closed-loop denitrification control results based on the NOx concentration upstream of the SCR.

[0123] 2) Simultaneously generate a combustion-side coordinated adjustment request to absorb the ammonia supply surplus:

[0124] (5)

[0125] (6)

[0126] (7)

[0127] Wherein, ΔEGR is the exhaust gas recirculation ratio adjustment request, ΔH2 is the hydrogen supply adjustment request, and ΔDiesel is the diesel injection quantity adjustment request. These are calibration coefficients, obtained from engine bench tests or vehicle calibration, and can be set in segments according to engine speed and load range.

[0128] Among them, the correction of ΔDiesel may include reducing the diesel injection quantity or adjusting the injection strategy to reduce the injection quantity per unit cycle, thereby achieving the absorption of the ammonia supply margin and the suppression of the residual ammonia risk on the combustion side in conjunction with EGR and hydrogen supply changes when residual ammonia exceeds the limit.

[0129] 3) The above-mentioned adjustment request quantity is sent to the combustion control module as a constraint input quantity, and is superimposed or coordinated with the main control quantity (fuel injection quantity) based on the combustion stability target. It is used to increase the proportion of recirculated exhaust gas, increase the amount of hydrogen involved and appropriately modify the diesel injection quantity (i.e., through formula (5)-(7)) without reducing the SCR denitrification efficiency, so that the recirculated exhaust gas and hydrogen participate in the combustion process in tandem, thereby absorbing the ammonia supply margin on the combustion side and reducing the risk of residual ammonia accumulation downstream of SCR.

[0130] The combustion control module can be a software function module inside the ECU. It is used to receive the combustion-side coordinated adjustment request as a constraint input, and after superimposing or uniformly solving it with the main control quantity of the combustion stability target, output control commands for EGR, hydrogen supply and diesel injection.

[0131] The "combustion-side absorption of excess ammonia supply" specifically refers to: without compromising the SCR denitrification efficiency constraint, by increasing the exhaust gas recirculation ratio to reduce the intake oxygen concentration and air-fuel mixture heat capacity, increasing the hydrogen supply to enhance the air-fuel mixture reactivity and ignition reliability, and reducing or redistributing the diesel injection quantity to adjust the unit cycle energy supply, thereby synergistically altering the air-fuel mixture composition and combustion boundary conditions entering the cylinder. This reduces reliance on excessive ammonia supply from the SCR, causing the residual ammonia level downstream of the SCR to fall below the safe range below the residual ammonia threshold that varies with operating conditions. This combustion-side absorption process is achieved through the coordinated control of three adjustment channels: exhaust gas recirculation ratio, hydrogen supply, and diesel injection quantity. Its purpose is to simultaneously suppress residual ammonia accumulation and maintain engine combustion stability without reducing the SCR denitrification efficiency.

[0132] In the control framework of this invention, the exhaust gas recirculation ratio, hydrogen supply, and diesel injection quantity work synergistically as three complementary adjustment channels for combustion-side absorption of the SCR ammonia supply margin: exhaust gas recirculation is used to adjust the intake oxygen concentration and mixture heat capacity; hydrogen supply is used to improve the mixture reactivity and ignition reliability; and diesel injection quantity is used to maintain load output and combustion phase targets. Using only any one of these adjustment channels cannot simultaneously suppress residual ammonia accumulation and maintain combustion stability without compromising the SCR denitrification efficiency constraint. Therefore, the synergistic adjustment of these three elements within a unified closed-loop control framework constitutes the necessary functional combination for this invention to simultaneously suppress residual ammonia accumulation and maintain combustion stability without compromising the SCR denitrification efficiency constraint.

[0133] VIII. Cooperative Combustion Control and Joint State Feedback Method Based on Residual Ammonia State

[0134] Within each control cycle, ECU17 executes the following coordinated combustion control process to simultaneously constrain SCR denitrification efficiency, downstream residual ammonia state, and engine combustion stability indicators within a single closed-loop framework. This achieves functional-level coordinated control of SCR operating status information entering the combustion control loop. This constitutes a unified closed-loop control framework with the downstream residual ammonia state as the core coupled variable, avoiding independent adjustments and conflicts between SCR denitrification control and engine combustion control. "SCR operating status information entering the combustion control loop" means that the downstream residual ammonia state, obtained from upstream exhaust gas information and operating parameters through a residual ammonia state estimation model, is written as an explicit system state variable into the engine-SCR joint state vector and participates in solving the control input vector in the joint state feedback law or model predictive control framework. This allows the residual ammonia state to simultaneously participate in the closed-loop adjustment process of urea injection quantity, exhaust gas recirculation ratio, hydrogen supply quantity, and diesel injection quantity, rather than merely existing as a monitoring or alarm signal. In this way, the SCR operating status information is entered into the internal calculation link of the combustion control loop from the emission system side in the form of state variables, forming a cross-system closed-loop control structure with the residual ammonia state quantity downstream of SCR as the core coupled variable.

[0135] 1) The ECU17 receives the cylinder pressure signal p(θ) collected by the cylinder pressure sensor 18 and calculates the following combustion characteristic quantities based on the crankshaft angle synchronous sampling data (the crankshaft angle is obtained by a synchronous sampling device installed on the engine crankshaft): combustion phase CA50, indicated mean effective pressure variation coefficient COVIMEP and ignition delay time ID.

[0136] 2) ECU17 compares the above combustion characteristic quantities with the corresponding target values ​​to obtain the combustion stability error term:

[0137] (8)

[0138] (9)

[0139] (10)

[0140] in, , , The target values ​​for CA50, COVIMEP, and ID are set in ECU17. The corresponding target values ​​are read from the pre-calibrated target combustion characteristic quantity mapping table according to the current operating conditions by looking up the table.

[0141] 3) ECU17 constructs a system state vector to characterize the engine-SCR coupled dynamics:

[0142] (11)

[0143] in, This represents the residual ammonia state quantity downstream of the SCR after filtering.

[0144] 4) ECU17 constructs the control input vector:

[0145] (12)

[0146] Where EGR is the exhaust gas recirculation ratio, H2 is the hydrogen supply, and Diesel is the diesel injection quantity.

[0147] 5) ECU17 describes the system's dynamic relationships based on a discrete state-space model that includes the residual ammonia state quantity NH3_filt:

[0148] (13)

[0149] Wherein, A and B are system matrices, and w(k) is a disturbance term. The system matrices A and B are obtained from engine bench test data or vehicle road test data through least squares identification or recursive identification methods, or are obtained by linearizing the engine-SCR joint model based on physical mechanisms. They are used to characterize the engine-SCR coupled dynamic characteristics including the SCR residual ammonia state variables, and are stored in the calibration storage area of ​​ECU17. They are called according to engine speed and load partitioning to construct discrete state-space models or predictive models in model predictive control.

[0150] In some implementations, the discrete state-space model can be used as the prediction model for model predictive control. The optimal control input vector u that satisfies the denitrification efficiency constraint, residual ammonia state constraint and combustion stability constraint is solved in the rolling time domain. The first control quantity is applied to the actuator (injector 19) and then the next time domain cycle is entered.

[0151] 6) Based on a joint state feedback law that includes residual ammonia state variables, ECU17 implements unified closed-loop regulation of SCR denitrification control and combustion control.

[0152] (14)

[0153] in, K represents the state feedback gain matrix, where K is the feedforward control variable based on engine speed and load. Let J be the system target state vector, and J be the combustion stability error feedback gain matrix. .

[0154] The state feedback gain matrix K is used to integrate SCR residual ammonia state parameters, engine speed and load, combustion phase CA50, and combustion stability indicators. The system state vector x, including ignition delay time ID, and the system target state vector The deviation between them is mapped to the adjustment of urea injection quantity, exhaust gas recirculation ratio, hydrogen supply quantity and diesel injection quantity.

[0155] In some implementations, K is determined by ECU17 based on system matrices A and B and the system target state vector. The state feedback gain matrix K is obtained through cost function optimization or pole placement, either offline or online. The cost function is used to simultaneously minimize the downstream residual ammonia state deviation of SC, the SCR denitrification efficiency deviation, and the combustion stability index deviation, and to apply penalty weights to the rate of change of urea injection quantity, exhaust gas recirculation ratio, hydrogen supply quantity, and diesel injection quantity. The state feedback gain matrix K is calibrated and stored in partitions according to engine speed and load conditions. During operation, ECU17 reads the corresponding state feedback gain matrix K from the calibration storage area according to the current engine speed and load range, and substitutes it into the joint state feedback law to calculate the updated values ​​of each control quantity.

[0156] In some implementations, the system target state vector The target components are adaptively set by ECU17 based on the current engine operating conditions and include at least the following:

[0157] (1) Target state of residual ammonia in SCR It is set to reduce the residual ammonia state quantity downstream of the SCR. Maintaining residual ammonia threshold The following target values ​​are within the safe range that are close to this threshold, for example: , where κ ranges from 0.6 to 0.9;

[0158] (2) SCR denitrification efficiency target status It is set as the minimum denitrification efficiency threshold to meet emission regulations, for example, 85%-95%;

[0159] (3) Combustion stability target state, which includes target combustion phase Combustion stability threshold and target ignition delay .

[0160] In some implementations, the ECU17 reads the values ​​of the target components from a pre-calibrated target state mapping table based on the engine speed n and load L using a lookup table or empirical function.

[0161] In one embodiment, J is a 4×3 matrix, whose row vectors correspond to four control quantities: urea injection quantity, exhaust gas recirculation ratio, hydrogen supply quantity, and diesel injection quantity, respectively, and whose column vectors correspond to... , and Three error components.

[0162] In some implementations, the combustion stability error feedback gain matrix J is calibrated and set by ECU17 according to engine speed and load zones, and is stored in the ECU calibration storage area together with system matrices A, B and state feedback gain matrix K, and is called according to the operating condition zone.

[0163] By unifying the target states of SCR residual ammonia, SCR denitrification efficiency, and combustion stability into the system target state vector. Furthermore, the combustion stability error term is explicitly introduced into the joint state feedback law through the feedback gain matrix J, so that the SCR operating state information and combustion stability constraints converge collaboratively within the same closed-loop control framework.

[0164] This avoids independent adjustments and conflicts between SCR denitrification control and engine combustion control, and improves emission control accuracy and combustion stability under transient operating conditions and fuel characteristic changes.

[0165] In some implementations, the feedforward control quantity The coordinated strategy can be set according to engine load status: engine load L is expressed as a percentage relative to rated load and is divided into low load range (L≤30%), medium load range (30% < L≤70%), and high load range (L>70%). Under low load conditions, the exhaust gas recirculation ratio is 15%-35%, the hydrogen supply ratio is 5%-25%, and the diesel injection quantity is reduced by 5%-20% compared to the hydrogen-free baseline condition, increasing the exhaust gas recirculation ratio and hydrogen supply ratio to improve ignition reliability and combustion stability; under medium load conditions, the exhaust gas recirculation ratio is 10%-25%, the hydrogen supply ratio is 5%-20%, and the diesel injection quantity is determined by load demand and target combustion phase. The diesel injection quantity, exhaust gas recirculation ratio, and hydrogen supply quantity are jointly determined and coordinated to balance efficiency and emissions. Under high load conditions, the exhaust gas recirculation ratio is set at 0%-15%, the hydrogen supply ratio is set at 0%-10%, and the diesel injection quantity is increased by 10%-30% compared to medium load conditions. The diesel injection ratio is increased and the exhaust gas recirculation ratio is limited to avoid insufficient power and excessive dilution, thereby achieving zoned coordinated control under the constraint of residual ammonia.

[0166] In some implementations, the state feedback gain matrix K is also calibrated according to engine speed and load zones, and is stored together with the system matrices A and B in the ECU calibration storage area and called according to the operating condition zone to adapt to the coupling dynamic characteristics under different operating conditions.

[0167] 7) Before outputting the four control quantities—urea injection quantity, exhaust gas recirculation ratio, hydrogen supply ratio, and diesel injection quantity—ECU17 applies amplitude and rate-of-change constraints to each control quantity to ensure that each actuator operates within the allowable physical range. Simultaneously, ECU17 smooths the control quantities using a first-order inertial filter or slope limiter to avoid combustion shocks and emission fluctuations caused by sudden changes in control quantities during transient conditions. The constrained and smoothed control quantities are then sent by ECU17 to the urea injector, EGR valve 13, jet valve 4, and fuel injector 19, respectively. In practical applications, under special operating conditions (such as rapid vehicle acceleration), priority is given to meeting emission standards (i.e., controlling the urea injection quantity first), followed by consideration of diesel engine power and combustion stability (i.e., controlling the diesel injection quantity, exhaust gas recirculation ratio, and hydrogen supply ratio sequentially); under other operating conditions, the above control quantities are controlled synchronously.

[0168] In some implementations, ECU17 solves for the control input vector u in a multi-objective optimization form within a joint state feedback control or model predictive control framework that includes the SCR residual ammonia state variable. Its objective function includes at least minimizing the SCR downstream residual ammonia state deviation, minimizing the combustion stability index deviation, and minimizing fuel consumption or energy consumption. Its constraints include at least the lower limit constraint of SCR denitrification efficiency, actuator amplitude and rate of change constraint, and safety threshold constraint.

[0169] IX. Closed-loop control process of SCR entering the combustion control loop during operation

[0170] During engine operation, ECU17 performs coordinated control according to the following closed-loop process, which is used to simultaneously constrain the SCR denitrification efficiency, the residual ammonia state downstream of SCR and the engine combustion stability index within a single control loop, thereby realizing functional-level coordinated control of SCR operating status information entering the combustion control loop.

[0171] The SCR denitrification efficiency can be determined by the upstream of the SCR. Downstream of SCR (Calculated using either downstream NOx sensors or model estimation).

[0172] 1) ECU17 collects the NOx concentration output from the exhaust gas composition analysis unit 15 located upstream of the SCR. With CO concentration And simultaneously collect exhaust temperature Exhaust pressure The engine speed n and load L are used to characterize the SCR inlet conditions and engine operating status.

[0173] 2) ECU17 is based on the above Urea injection volume Exhaust temperature Exhaust flow rate and catalyst activity decay factor (Optional) Execute the residual ammonia state estimation algorithm to obtain the residual ammonia estimate. The residual ammonia state parameters are then obtained through low-pass filtering for control decision-making. .

[0174] 3) ECU17 will The residual ammonia threshold varies with engine speed n and load L The comparison is used to determine whether the SCR is currently in a state of excessive ammonia supply.

[0175] 4) When satisfied ≤ At this time, ECU17 maintains the SCR denitrification priority control mode and sets the urea injection quantity according to the NOx closed-loop control results. And maintain the current combustion control parameters unchanged.

[0176] 5) When NH3_filt > NH3_th(n,L), ECU17 enters the residual ammonia suppression mode and simultaneously executes the reverse constraint control step: applying a reduction correction amount Δ to the urea injection quantity. (Δ) The system generates exhaust gas recirculation ratio adjustment request ΔEGR, hydrogen supply adjustment request ΔH2, and diesel injection adjustment request ΔDiesel. These adjustment requests are sent to the combustion control module as constraint inputs to reduce the residual ammonia state downstream of the SCR by changing the combustion side boundary conditions to absorb the ammonia supply margin.

[0177] 6) The ECU17 synchronously acquires the in-cylinder pressure signal p(θ) output by the cylinder pressure sensor 18, and calculates the combustion phase CA50, the coefficient of variation of the indicated average effective pressure COVIMEP, and the ignition delay time ID to characterize the current combustion stability of the engine.

[0178] 7) ECU17 will measure the residual ammonia status. Engine speed n, load L, combustion characteristic quantities (CA50, COVIMEP, ID), and exhaust temperature Exhaust flow rate Together they form the system state vector x, and based on the discrete state-space model containing the residual ammonia state variables, joint state feedback control is performed to calculate the updated control input vector u.

[0179] 8) Before outputting the control quantity, ECU17 applies amplitude constraints and rate of change constraints to the urea injection quantity, exhaust gas recirculation ratio, hydrogen supply ratio, and diesel injection quantity, respectively, and smooths the control quantity through a first-order inertial filter or slope limiter.

[0180] 9) The control quantity after constraint and smoothing is sent by ECU17 to urea injector, EGR valve 13, jet valve 4 and injector 19 respectively, and enters the next control cycle.

[0181] Through the above closed-loop process, the SCR denitrification efficiency, the SCR downstream residual ammonia, and the engine combustion stability are coordinated and converged to the preset target range within the same control loop, thereby avoiding independent and conflicting adjustments between SCR denitrification control and engine combustion control.

[0182] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A diesel engine combustion cooperative control system based on an SCR operation state, characterized by, It comprises a cylinder (20) and an ECU (17), wherein the cylinder (20) is provided with a cylinder pressure sensor (18); The cylinder (20) is provided with an air filter (9), a compressor (10) and an intercooler (8) in sequence along the fresh air flow direction of the intake pipeline of the cylinder (20); The cylinder (20) is provided with a waste gas composition analysis unit (15) and an SCR aftertreatment system (14) in sequence along the exhaust direction of the exhaust pipeline of the cylinder (20); The intake pipeline and the exhaust pipeline are provided with an EGR valve (13) therebetween; A hydrogen injection valve (4) is arranged on the intake pipeline close to the cylinder (20), and the hydrogen injection valve (4) is connected to a hydrogen pressure regulating device (3), a hydrogen metering device (2) and a hydrogen generating device (1) in sequence; The cylinder (20) is provided with an oil injector (19), and a pipeline, which is in communication with the oil injector (19) and the diesel tank (5), is provided with a diesel filter (6) and a fuel pump (7) in sequence; The ECU (17) communicates with the hydrogen injection valve (4), the oil injector (19), the EGR valve (13), the waste gas composition analysis unit (15) and the cylinder pressure sensor (18).

2. The SCR operating state based diesel combustion coordination system of claim 1, wherein, It further comprises an exhaust gas combustible component detection unit (11) located at the rear part of the SCR aftertreatment system (14) along the exhaust gas flow direction.

3. The SCR operating state based diesel combustion coordination system of claim 2, wherein, It further comprises an emission recovery coordination processing unit (12) located at the rear part of the exhaust gas combustible component detection unit (11) along the exhaust gas flow direction.

4. A method for the combustion coordination control system of a diesel engine based on the SCR operation state according to any one of claims 1-3, characterized in that: The waste gas composition analysis unit (15) collects the NOx concentration in the exhaust gas upstream of the SCR in real time, and synchronously collects the exhaust temperature, the exhaust pressure and the speed and load of the engine, and inputs the signals into the ECU (17); The ECU (17) constructs a residual ammonia estimation model based on the NOx concentration upstream of the SCR, the urea injection amount, the exhaust gas flow rate, the exhaust gas temperature, and a catalyst activity degradation factor, estimates the residual ammonia state quantity that can exist downstream of the SCR , corrects the residual ammonia state quantity by introducing the dynamic state of the ammonia storage of the SCR, and obtains an estimated value of the residual ammonia that takes into account the hysteresis effect of the ammonia storage and release of the SCR , and after being processed by filtering or a state observer, the estimated value is used as the residual ammonia state quantity that enters the combustion control loop . comparing the residual ammonia state quantity with the residual ammonia threshold value varying with engine speed and load _th when the residual ammonia state quantity exceeds the corresponding threshold value, imposing a reverse constraint correction on the urea injection quantity without violating the SCR denitration efficiency constraint, and simultaneously generating a combustion-side collaborative adjustment request quantity for absorbing the SCR ammonia supply margin; the ECU (17) adjusts the exhaust gas recirculation ratio, the hydrogen supply quantity, and the diesel injection quantity based on the combustion-side collaborative adjustment request quantity, so that the recirculated exhaust gas, hydrogen, and fresh air jointly participate in the intake and combustion process; The ECU (17) further uses the residual ammonia state variable The engine speed and load, the combustion phase CA50, the combustion stability index COVIMEP, the ignition delay time ID, and the exhaust temperature and exhaust flow rate jointly constitute a joint state vector, and based on a discrete state space model or model predictive control containing the residual ammonia state variable, the ECU (17) implements unified closed-loop regulation of the urea injection amount, the exhaust gas recirculation ratio, the hydrogen supply ratio, and the diesel injection amount, so that the SCR denitration efficiency state, the SCR downstream residual ammonia state, and the engine combustion stability state are cooperatively converged to a preset target interval within the same control loop.

5. The method of claim 4, wherein, The residual ammonia estimation model is: wherein, is the concentration of nitrogen oxides upstream of the SCR, is the amount of urea injection, is the exhaust gas flow rate, is the exhaust gas temperature, is the catalyst activity decay factor.

6. The method of claim 5, wherein, The residual ammonia estimation value considering the ammonia storage and release hysteresis effect of the SCR is obtained by the following method: wherein the ammonia supply margin , the SCR theoretical ammonia demand , is the ammonia storage state variable.

7. The method of claim 6, wherein, the ammonia storage state variable The update is performed as follows: wherein, is the ammonia adsorption efficiency coefficient, is the ammonia release decay coefficient.

8. The method of claim 4, wherein, The reverse constraint correction on the urea injection amount is specifically as follows: Based on the excess ammonia over-limit amplitude , the scale factor Decreasing correction to the urea injection amount: wherein, sets the urea injection amount in accordance with the closed-loop de-NOx control result based on the NOx concentration upstream of the SCR The combustion side coordination adjustment request amount for absorbing the ammonia supply margin of the SCR is synchronously generated, and specifically as follows: wherein, ΔEGR is a request amount of exhaust gas recirculation ratio adjustment, ΔH2 is a request amount of hydrogen supply adjustment, ΔDiesel is a request amount of diesel injection adjustment, , , , are all calibration coefficients.

9. The method of claim 4, wherein, The unified closed-loop adjustment adopts the following joint state feedback law containing the residual ammonia state variable: wherein, is an engine speed and load based feed forward control amount, K is a state feedback gain matrix, is a system state vector, is a system target state vector, J is a combustion stability error feedback gain matrix, , , , , , , are target values of CA50, COVIMEP, and ID, respectively.

10. The method of claim 4, wherein, The ECU (17) applies amplitude constraint and change rate constraint to each control amount before outputting the urea injection amount, the exhaust gas backflow ratio, the hydrogen supply ratio and the diesel injection amount, and performs smoothing processing.

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