Method for determining carbon deposition amount of oil injector and related product

Abstract

The invention provides a method for determining the carbon deposition amount of an oil injector and a related product. The method for determining the carbon deposition amount of the fuel injector comprises the steps that the rail pressure, the air inlet pressure, the fuel oil temperature in a common rail pipe, the fuel supply advance angle of each cylinder, the fuel supply duration angle of each cylinder, the circulating fuel injection amount, the fuel injection advance angle of each cylinder, the fuel injection duration angle of each cylinder, the total operation time of an engine and the expected rail pressure of the period are obtained; determining a determination flag bit of carbon deposition of the fuel injector; engine cylinder internal pressure, expected engine cylinder injection pressure difference and actual engine cylinder injection pressure difference are obtained through calculation; the actual fuel injection quantity of each cylinder is obtained through calculation; calculating to obtain the carbon deposition amount / rate of each cylinder; after a new engine or a new oil injector is replaced, the initial equivalent carbon deposition amount test working condition is operated, and the previous steps are executed in sequence to obtain the initial equivalent carbon deposition amount / rate of each cylinder; and obtaining the actual carbon deposition amount / rate of each cylinder. Compared with the prior art, the method for determining the carbon deposition amount of the fuel injector and the related product can accurately determine the carbon deposition amount of the fuel injector in real time.

Description

Technical Field

[0001] This invention relates to the field of engine fuel injection control technology, and more specifically, to a method for determining the amount of carbon deposits in fuel injectors and related products. Background Technology

[0002] Current engines typically employ high-pressure common rail fuel supply technology. Under prolonged combustion conditions, this can easily lead to injector coking (carbon buildup). Injector coking causes numerous negative consequences, such as clogged injection nozzles, inaccurate fuel injection control, high emissions, and even pre-ignition. Currently, injector carbon buildup has become one of the major issues affecting engine efficiency. In some vehicles, injector carbon buildup is often estimated based on mileage. However, the amount of carbon buildup is highly dependent on operating conditions, and relying solely on mileage for estimation is inaccurate.

[0003] Studies have shown that cylinder leakage characteristics of piston-cylinder assemblies (i.e., the tendency of piston-cylinder assemblies to leak gas under high-pressure operating conditions), differences in the geometry and size of cylinder assembly combustion chambers, etc., can lead to changes in engine cylinder pressure, inconsistent combustion in each cylinder, and differences in carbon deposits on the injectors of each cylinder.

[0004] Chinese invention patent application number 202210098090.7, entitled "A Method for Determining the Amount of Carbon Deposits in Fuel Injectors and Related Products," discloses a method for determining the amount of carbon deposits in fuel injectors. This method uses a combination of injector temperature, injection rail pressure, and injection frequency under different operating conditions, while also considering ignition efficiency, intake air temperature, coolant temperature, and air-fuel ratio, to conduct a carbon deposit generation test. However, it fails to identify the different carbon deposit situations in fuel injectors caused by uneven combustion in each cylinder due to differences in piston-cylinder assembly characteristics. This method is based on experimental data (PN (mass / number of suspended solids) and PM (mass of particulate matter) emissions in the exhaust gas), deriving a carbon deposit generation calculation model from the experimental data, and then determining the carbon deposit generation under various operating conditions. The experimental procedures are cumbersome, and the data calculation and processing workload is large. With differences between mass-produced engines or extended engine operating time, the cumulative error will increase, leading to a decrease in prediction accuracy.

[0005] Chinese invention patent No. 00813294.1, entitled "Method, Control Device and Internal Combustion Engine for Operating an Internal Combustion Engine", discloses a method for operating an internal combustion engine. This method determines injector carbon deposits based on the identification of cylinder balance adjustment failure and / or interruption at engine speed, but it cannot accurately quantify the amount of injector carbon deposits. It does not consider the uneven combustion in each cylinder of the engine caused by the difference in piston-cylinder assembly characteristics, which may lead to misjudgment of injector carbon deposits. Furthermore, it does not perform relevant tests and self-learning on new engines or after injector replacement, which is not conducive to determining the initial equivalent carbon deposit amount / rate of each cylinder.

[0006] Existing research, such as Wang Xiancheng et al.'s method for calculating characteristic parameters of carbon deposits in diesel engine injectors, calculates normalized characteristic parameters by simulating and analyzing the nozzle elongation and internal roughness at different engine speeds. Then, it uses the error between the simulated and experimental values ​​of the peak injection pressure to determine the nozzle elongation, and the error between the simulated and experimental values ​​of the peak injection rate to determine the internal roughness. However, this research only focuses on the characteristic parameters of carbon deposits in injectors and does not investigate the amount of carbon deposits.

[0007] Existing standards, such as NB / SH / T 6059-2022 (DW-10B method for test method of injector coking in common rail direct injection diesel engines), characterize the degree of injector coking (carbon deposit amount) by the power loss of the engine before and after the cyclic test. Specifically, it calculates the power loss by dividing the power reduction measured after 40 hours by the power measured after 0 hours. However, this standard cannot calculate the injector carbon deposit amount in real time, and the power reduction measured after 40 hours is not entirely due to injector carbon deposits.

[0008] Since it is impossible to accurately measure the weight of carbon deposits generated in fuel injectors in real time, there is an urgent need for a method that can quantify the amount / rate of carbon deposits in fuel injectors. Summary of the Invention

[0009] To address the aforementioned technical problems, the present invention aims to provide a method for determining the amount of carbon deposits in fuel injectors and related products that can accurately determine the amount of carbon deposits in fuel injectors in real time.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: A method for determining the amount of carbon deposits in a fuel injector, the method comprising: The system obtains the rail pressure, intake pressure, common rail fuel temperature, injection advance angle of each cylinder, injection duration angle of each cylinder, injection quantity of the cycle, injection advance angle and injection duration angle of each cylinder, total engine running time, and expected rail pressure for the current cycle. Based on the overlap between the injection advance angle and injection duration angle of each cylinder and the injection advance angle and injection duration angle of each cylinder in this cycle, as well as the cyclic injection quantity and rail pressure status, determine the indicator position for injector carbon buildup. Based on the rail pressure, intake pressure, injection advance angle and injection duration angle of each cylinder, and total engine running time of this cycle, the engine cylinder pressure, the expected injection pressure difference between each cylinder and the actual injection pressure difference between each cylinder are calculated. Based on the rail pressure, expected rail pressure, fuel temperature in the common rail, and injection pressure difference of each cylinder in this cycle, the actual fuel injection quantity of each cylinder is calculated. Based on the actual fuel injection quantity of each cylinder, the cyclic fuel injection quantity, the expected injection pressure difference between each cylinder of the engine, and the actual injection pressure difference between each cylinder of the engine in this cycle, the carbon deposit quantity / rate of each cylinder is calculated. After a new engine or a new injector is installed, run the initial equivalent carbon deposit test condition and perform the previous steps in sequence to obtain the initial equivalent carbon deposit / rate for each cylinder. The actual carbon deposit amount / rate of each cylinder is obtained by subtracting the initial equivalent carbon deposit amount / rate of each cylinder from the carbon deposit amount / rate of each cylinder mentioned in this cycle.

[0011] Preferably, the step of determining the indicator of injector carbon buildup based on the overlap between the injection advance angle and injection duration angle of each cylinder in the current cycle and the injection advance angle and injection duration angle of each cylinder, the cyclic injection quantity, and the rail pressure status includes the following steps: The fuel injector carbon deposit determination flag B=1 when all five of the following conditions are met; otherwise, the fuel injector carbon deposit determination flag B=0. The five conditions are as follows: (1) Determining carbon deposits in fuel injectors: enable C=1; (2) Injector fault flag D=0; When there is an open circuit fault or short circuit fault in any cylinder of the engine, the injector fault flag D=1. (3) The fuel supply and injection overlap flag E=0; when the fuel supply advance angle and fuel supply duration angle of each cylinder overlap with the fuel injection advance angle and fuel injection duration angle of each cylinder, the fuel supply and injection overlap flag E=1. (4) Cyclic injection quantity flag F=0; When the cyclic injection quantity of any cylinder of the engine is less than the cyclic injection quantity threshold, the cyclic injection quantity flag F=1; (5) Rail pressure status flag G = 0; when the absolute value of the rail pressure control deviation exceeds the unreasonable threshold value of the rail pressure control deviation or the absolute value of the rail pressure fluctuation exceeds the unreasonable threshold value of the rail pressure fluctuation for a period exceeding the duration threshold value, the rail pressure status flag G = 1; The rail pressure control deviation is the difference between the desired rail pressure and the actual rail pressure, and the rail pressure fluctuation is the difference between the maximum and minimum rail pressure values ​​within a certain period.

[0012] Preferably, based on the rail pressure, intake pressure, injection advance angle and injection duration angle of each cylinder, and total engine running time for this cycle, the engine cylinder pressure, the desired injection pressure difference between each cylinder, and the actual injection pressure difference between each cylinder are calculated, including the following steps: Calculate the midpoint of the injection advance angle based on the injection advance angle and injection duration angle of each cylinder.

[0013] in, The midpoint of the fuel injection advance angle. The injection advance angle for each cylinder, The injection duration angle for each cylinder; Calculate the cylinder pressure correction factor:

[0014] in, This is the cylinder pressure correction factor. This refers to the engine cylinder compression ratio. The adiabatic index, This is the midpoint of the fuel injection advance angle; Calculate the engine cylinder pressure:

[0015] in, This refers to the pressure inside the engine cylinder. This is the cylinder pressure correction factor. This is a correction factor for cylinder leakage characteristics. , Total engine running time. To accompany the total engine running time The pulse spectrum of the correction coefficient for varying cylinder leakage characteristics. This refers to the intake pressure. Calculate the desired injection pressure difference between each cylinder of the engine:

[0016] in, To achieve the desired injection pressure difference between the cylinders of the engine, For the desired rail pressure, This refers to the pressure inside the engine cylinder. Calculate the actual injection pressure difference between each cylinder of the engine:

[0017] in, This refers to the actual injection pressure difference in the first cylinder of the engine. This refers to the rail pressure of the first cylinder of the engine. This refers to the pressure inside the engine cylinder.

[0018] Preferably, the actual fuel injection quantity of each cylinder is calculated based on the rail pressure, desired rail pressure, common rail fuel temperature, and injection pressure difference between each cylinder of the engine in this cycle, including the following steps: Calculate the rail pressure drop of each cylinder in the engine: The rail pressure after fuel injection in each cylinder is subtracted from the rail pressure before fuel injection in each cylinder. This is the rail pressure drop of each cylinder. ; Calculate the bulk modulus of fuel based on the desired rail pressure and the fuel temperature inside the common rail:

[0019] in, The bulk modulus of fuel oil. For the desired rail pressure, This refers to the fuel temperature inside the common rail. The pulse spectrum of fuel bulk elastic modulus; Calculate the actual fuel injection quantity for each cylinder based on the pressure drop across the engine's cylinder rails and the bulk modulus of fuel elasticity:

[0020] in, This represents the actual fuel injection quantity of the first cylinder injector in the engine. The bulk modulus of fuel oil. This refers to the rail pressure drop before and after fuel injection at the injector of the first cylinder of the engine. This refers to the high-pressure fuel volume for the common rail system.

[0021] Preferably, the carbon deposit quantity / rate of each cylinder is calculated based on the actual fuel injection quantity of each cylinder in this cycle, the cyclic fuel injection quantity, the desired injection pressure difference between each cylinder of the engine, and the actual injection pressure difference between each cylinder of the engine, including the following steps: Calculate the amount / rate of carbon deposits in each cylinder:

[0022] in, The carbon deposit quantity / rate of the fuel injector in the first cylinder of the engine. This represents the actual fuel injection quantity of the first cylinder injector in the engine. This refers to the amount of fuel injected in a cycle. To achieve the desired injection pressure difference between the cylinders of the engine, This represents the actual injection pressure difference in the first cylinder of the engine.

[0023] Preferably, after a new engine is installed or a new injector is replaced, the initial equivalent carbon deposit test condition is run, and the preceding steps are performed sequentially to obtain the initial equivalent carbon deposit amount / rate for each cylinder. The initial equivalent carbon deposit test condition includes: The engine coolant temperature exceeds the coolant temperature threshold. The engine oil temperature exceeds the oil temperature threshold. The engine is maintained at a specific speed, and the engine speed fluctuation does not exceed the speed fluctuation threshold. The engine load is no load; The rail pressure control deviation shall not exceed the rail pressure control deviation threshold. The rail pressure fluctuation does not exceed the rail pressure fluctuation threshold.

[0024] Preferably, after a new engine or a new injector is installed, the initial equivalent carbon deposit test condition is run, and the preceding steps are executed sequentially to obtain the initial equivalent carbon deposit amount / rate for each cylinder. The process also includes storing the calculated initial equivalent carbon deposit amount / rate for each cylinder in the electronic control unit (ECU).

[0025] Preferably, after obtaining the actual carbon deposit amount / rate of each cylinder, the method further includes: when the actual carbon deposit amount / rate of each cylinder in the current cycle exceeds the carbon deposit threshold, an alarm and / or torque limiting are triggered.

[0026] An electronic device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program stored in the memory to implement the steps of the injector carbon deposit determination method as described above.

[0027] A computer program product includes a computer program that, when executed by a processor, implements the steps of the injector carbon deposit determination method as described above.

[0028] Compared with existing technologies, this invention calculates the carbon deposit quantity / rate of each cylinder in real time by measuring the engine cylinder pressure, the expected injection pressure difference between cylinders, the actual injection pressure difference between cylinders, and the actual fuel injection quantity of each cylinder. This results in a normalized index of the injector carbon deposit quantity / rate, allowing for accurate real-time determination of the injector carbon deposit quantity. Furthermore, by correcting for differences in cylinder leakage characteristics of the piston-cylinder assembly and by performing self-learning on the initial equivalent carbon deposit quantity / rate of each cylinder under relevant test conditions after a new engine or replacement of the injector, this invention eliminates variations in fuel injection quantity caused by changes in engine cylinder pressure due to differences in piston-cylinder assembly cylinder leakage characteristics, and differences in the geometry and size of the cylinder assembly combustion chamber. This reduces or even eliminates adverse factors affecting the determination of injector carbon deposit quantity, further improving the accuracy of injector carbon deposit quantity determination. Attached Figure Description

[0029] Figure 1 This is a flowchart of a method for determining the amount of carbon deposits in an injector provided in an embodiment of the present invention.

[0030] Figure 2 yes Figure 1 The flowchart of step S3 in the method for determining the amount of carbon deposits in the fuel injector is shown.

[0031] Figure 3 yes Figure 1 The flowchart of step S4 in the method for determining the amount of carbon deposits in the fuel injector is shown. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be described in further detail below with reference to the embodiments and accompanying drawings.

[0033] This embodiment provides a method for determining the amount of carbon deposits in fuel injectors, such as... Figure 1 As shown, the method for determining the amount of carbon deposits in the fuel injector includes the following steps S1-S8: Step S1: Obtain the rail pressure, intake pressure, common rail fuel temperature, injection advance angle of each cylinder, injection duration angle of each cylinder, injection quantity of each cycle, injection advance angle and injection duration angle of each cylinder, total engine running time, and desired rail pressure for this cycle.

[0034] It should be noted that the rail pressure, intake pressure, and common rail fuel temperature are values ​​monitored in real time by the ECU. The total engine running time, injection quantity per cycle, injection advance angle for each cylinder, injection duration angle for each cylinder, injection advance angle for each cylinder, and desired rail pressure are calculated in real time by the ECU. The injection duration angle for each cylinder is calculated by the ECU based on the injection quantity for each cylinder and the desired rail pressure.

[0035] It should be noted that the total engine running time, cyclic fuel injection quantity, fuel injection advance angle of each cylinder, fuel injection duration angle of each cylinder, fuel injection advance angle of each cylinder, fuel injection duration angle of each cylinder, and the acquisition of the desired rail pressure are known technologies and will not be described in this specification.

[0036] Step S2: Based on the overlap between the injection advance angle and injection duration angle of each cylinder and the injection advance angle and injection duration angle of each cylinder in this cycle, as well as the cyclic injection quantity and rail pressure status, determine the indicator position for injector carbon buildup.

[0037] Step S3: Based on the rail pressure, intake pressure, injection advance angle and injection duration angle of each cylinder, and total engine running time of this cycle, calculate the engine cylinder pressure, the desired injection pressure difference between each cylinder, and the actual injection pressure difference between each cylinder.

[0038] It should be noted that the desired injection pressure difference between each cylinder of the engine is the difference between the desired rail pressure and the pressure inside the engine cylinder, while the actual injection pressure difference between each cylinder of the engine is the difference between the rail pressure and the pressure inside the engine cylinder. The pressure inside the engine cylinder varies with the crankshaft rotation angle.

[0039] Step S4: Calculate the actual fuel injection quantity for each cylinder based on the rail pressure, desired rail pressure, fuel temperature in the common rail, and injection pressure difference between each cylinder of the engine in this cycle.

[0040] Step S5: Calculate the carbon deposit quantity / rate of each cylinder based on the actual fuel injection quantity of each cylinder in this cycle, the cyclic fuel injection quantity, the expected injection pressure difference between each cylinder of the engine, and the actual injection pressure difference between each cylinder of the engine.

[0041] Step S6: After the new engine is installed or the injectors are replaced, run the initial equivalent carbon deposit test condition and execute the previous steps S1 to S5 in sequence to obtain the initial equivalent carbon deposit amount / rate for each cylinder.

[0042] Step S7: Subtract the initial equivalent carbon deposit amount / rate of each cylinder from the carbon deposit amount / rate of each cylinder in this cycle to obtain the actual carbon deposit amount / rate of each cylinder.

[0043] Step S8: When the actual carbon deposit amount / rate of each cylinder in this cycle exceeds the carbon deposit threshold, an alarm and / or torque limitation will be triggered.

[0044] It should be noted that one cycle is 10ms. Optionally, the algorithm can be executed in response to the occurrence of an event.

[0045] Preferably, step S2, determining the indicator of injector carbon buildup based on the overlap between the injection advance angle and injection duration angle of each cylinder in the current cycle and the injection advance angle and injection duration angle of each cylinder, the cyclic injection quantity, and the rail pressure status, includes the following steps: The fuel injector carbon deposit determination flag B=1 when all five of the following conditions are met; otherwise, the fuel injector carbon deposit determination flag B=0. The five conditions are as follows: (1) Determining carbon deposits in fuel injectors: enable C=1; (2) Injector fault flag D=0; When there is an open circuit fault or short circuit fault in any cylinder of the engine, the injector fault flag D=1. (3) The fuel supply and injection overlap flag E=0; when the fuel supply advance angle and fuel supply duration angle of each cylinder overlap with the fuel injection advance angle and fuel injection duration angle of each cylinder, the fuel supply and injection overlap flag E=1. (4) Cyclic injection quantity flag F=0; When the cyclic injection quantity of any cylinder of the engine is less than the cyclic injection quantity threshold, the cyclic injection quantity flag F=1; (5) Rail pressure status flag G = 0; when the absolute value of the rail pressure control deviation exceeds the unreasonable threshold value of the rail pressure control deviation or the absolute value of the rail pressure fluctuation exceeds the unreasonable threshold value of the rail pressure fluctuation for a period exceeding the duration threshold value, the rail pressure status flag G = 1.

[0046] It should be noted that the rail pressure control deviation is the difference between the desired rail pressure and the actual rail pressure, and the rail pressure fluctuation is the difference between the maximum and minimum rail pressure values ​​within a certain period. It should also be noted that the certain period can be, but is not limited to, one engine operating cycle.

[0047] In this embodiment, no specific restrictions are placed on the threshold value. It is easy to understand that each threshold value has its corresponding preset range.

[0048] Preferably, such as Figure 2 As shown, step S3, which calculates the engine cylinder pressure, the desired injection pressure difference between the engine cylinders, and the actual injection pressure difference between the engine cylinders based on the rail pressure, intake pressure, injection advance angle and injection duration angle of each cylinder, and total engine running time in this cycle (the following calculation is based on the first cylinder of the engine; the calculation method for the other cylinders is the same as that for the first cylinder, and will not be repeated here), includes the following steps S31-S36.

[0049] Step S31: Calculate the midpoint of the injection advance angle based on the injection advance angle and injection duration angle of each cylinder:

[0050] in, The midpoint of the fuel injection advance angle. The injection advance angle for each cylinder, The injection duration angle for each cylinder.

[0051] Preferably, the high-pressure common rail fuel supply method adopts a multi-injection combination method, and the midpoint of the fuel injection advance angle is the midpoint of the main injection advance angle.

[0052] Step S32: Calculate the cylinder pressure correction factor:

[0053] in, This is the cylinder pressure correction factor. This refers to the engine cylinder compression ratio. The adiabatic index, This is the midpoint of the fuel injection advance angle.

[0054] Step S33: Calculate the cylinder leakage characteristic correction factor based on the total engine running time:

[0055] in, This is a correction factor for cylinder leakage characteristics. Total engine running time. To accompany the total engine running time The pulse spectrum of the correction coefficient for the changing cylinder leakage characteristics.

[0056] It should be noted that the cylinder leakage characteristic correction coefficient pulse spectrum that varies with the total engine running time can be obtained through engine durability testing.

[0057] Step S34: Calculate the engine cylinder pressure:

[0058] in, This refers to the pressure inside the engine cylinder. This is the cylinder pressure correction factor. This is a correction factor for cylinder leakage characteristics. This refers to the intake pressure.

[0059] It should be noted that engine cylinder pressure refers to the pressure inside the engine cylinder. This cylinder pressure acts as the back pressure relative to the fuel injector. The cylinder pressure, which varies depending on engine operating conditions, is used to calculate and adjust the injector opening timing to obtain the required fuel injection quantity.

[0060] Step S35: Calculate the desired injection pressure difference between each cylinder of the engine:

[0061] in, To achieve the desired injection pressure difference between the cylinders of the engine, For the desired rail pressure, This refers to the pressure inside the engine cylinder.

[0062] Step S36: Calculate the actual injection pressure difference between each cylinder of the engine:

[0063] in, This refers to the actual injection pressure difference in the first cylinder of the engine. This refers to the rail pressure of the first cylinder of the engine. This refers to the pressure inside the engine cylinder.

[0064] Preferably, such as Figure 3 As shown, step S4, which calculates the actual fuel injection quantity of each cylinder based on the rail pressure, expected rail pressure, fuel temperature in the common rail, and injection pressure difference of each cylinder in the current cycle (the calculation is based on the first cylinder of the engine, and the calculation method for the other cylinders of the engine is the same as that for the first cylinder, and will not be repeated here), includes the following steps S41-S43.

[0065] Step S41: Calculate the rail pressure drop of each cylinder: The result of subtracting the rail pressure before fuel injection from the rail pressure after fuel injection in each cylinder is the rail pressure drop of each cylinder. .

[0066] Step S42: Calculate the bulk modulus of fuel based on the desired rail pressure and the fuel temperature in the common rail:

[0067] in, The bulk modulus of fuel oil. For the desired rail pressure, This refers to the fuel temperature inside the common rail. The pulse spectrum represents the bulk elastic modulus of fuel.

[0068] Step S43: Calculate the actual fuel injection quantity of each cylinder injector based on the pressure drop across the engine's cylinder rails.

[0069] in, This represents the actual fuel injection quantity of the first cylinder injector in the engine. The bulk modulus of fuel oil. This refers to the rail pressure drop before and after fuel injection at the injector of the first cylinder of the engine. This refers to the high-pressure fuel volume for the common rail system.

[0070] Preferably, step 5, which involves calculating the carbon deposit quantity / rate of each cylinder based on the actual fuel injection quantity of each cylinder in this cycle, the cyclic fuel injection quantity, the desired injection pressure difference between each cylinder of the engine, and the actual injection pressure difference between each cylinder of the engine (the following calculation is based on the first cylinder of the engine as an example; the calculation method for other cylinders of the engine is the same as that for the first cylinder, and will not be repeated here), includes the following steps: Calculate the amount / rate of carbon deposits in each cylinder:

[0071] in, The carbon deposit quantity / rate of the fuel injector in the first cylinder of the engine. This represents the actual fuel injection quantity of the first cylinder injector in the engine. This refers to the amount of fuel injected in a cycle. To achieve the desired injection pressure difference between the cylinders of the engine, This represents the actual injection pressure difference in the first cylinder of the engine.

[0072] Preferably, in step S6, after the new engine or the replacement of the new injectors, the initial equivalent carbon deposit test condition is run, and the initial equivalent carbon deposit amount / rate of each cylinder is obtained by sequentially executing the previous steps. The initial equivalent carbon deposit test condition includes, but is not limited to: The engine coolant temperature exceeds the coolant temperature threshold. The engine oil temperature exceeds the oil temperature threshold. The engine is maintained at a specific speed, and the engine speed fluctuation does not exceed the speed fluctuation threshold. The engine load is no load; The rail pressure control deviation shall not exceed the rail pressure control deviation threshold. The rail pressure fluctuation does not exceed the rail pressure fluctuation threshold.

[0073] The calculated initial equivalent carbon deposit amount / rate for each cylinder will be stored in the electronic control unit (ECU).

[0074] It should be noted that the specific speed can be, for example, 1500 rpm, 2000 rpm, etc. The speed fluctuation is the difference between the maximum and minimum speed within a certain period. The rail pressure control deviation is the difference between the expected rail pressure and the rail pressure. The rail pressure fluctuation is the difference between the maximum and minimum rail pressure within a certain period.

[0075] Preferably, step S8: When the actual carbon deposit amount / rate of each cylinder in this cycle exceeds the carbon deposit threshold, an alarm and / or torque limiting are triggered, including the following steps: When the actual carbon deposit amount / rate of each cylinder exceeds the carbon deposit threshold, the electronic control unit (ECU) confirms that "the carbon deposit of the injector of engine cylinder number I has deteriorated to the point that it needs to be repaired or replaced", and can limit the engine output and / or issue a warning to the driver based on the calibration data pre-stored in the ECU.

[0076] Engine output limiting may include implementing limp-home mode or fault protection mode. Warnings may include MIL (Malfunction Indicator Light) illumination, warning sounds, etc.

[0077] Experimental results show that carbon buildup in fuel injectors is the primary cause of injector flow loss, and the amount of carbon buildup is positively correlated with the flow loss. Therefore, this embodiment calculates and determines the amount of carbon buildup in fuel injectors based on their flow loss; the calculation process is simple and the results are accurate.

[0078] This embodiment also provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor is used to execute the computer program stored in the memory to implement the steps of the injector carbon deposit determination method as described above.

[0079] This embodiment also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the injector carbon deposit determination method as described above.

[0080] The above description is merely an embodiment of the present invention. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements all fall within the protection scope of the present invention.

Claims

1. A method for determining the amount of carbon deposits in a fuel injector, characterized in that, The method includes: The system obtains the rail pressure, intake pressure, common rail fuel temperature, injection advance angle of each cylinder, injection duration angle of each cylinder, injection quantity of the cycle, injection advance angle and injection duration angle of each cylinder, total engine running time, and expected rail pressure for the current cycle. Based on the overlap between the injection advance angle and injection duration angle of each cylinder and the injection advance angle and injection duration angle of each cylinder in this cycle, as well as the cyclic injection quantity and rail pressure status, determine the indicator position for injector carbon buildup. Based on the rail pressure, intake pressure, injection advance angle and injection duration angle of each cylinder, and total engine running time of this cycle, the engine cylinder pressure, the expected injection pressure difference between each cylinder and the actual injection pressure difference between each cylinder are calculated. Based on the rail pressure, expected rail pressure, fuel temperature in the common rail, and injection pressure difference of each cylinder in this cycle, the actual fuel injection quantity of each cylinder is calculated. Based on the actual fuel injection quantity of each cylinder, the cyclic fuel injection quantity, the expected injection pressure difference between each cylinder of the engine, and the actual injection pressure difference between each cylinder of the engine in this cycle, the carbon deposit quantity / rate of each cylinder is calculated. After a new engine or a new injector is installed, run the initial equivalent carbon deposit test condition and perform the previous steps in sequence to obtain the initial equivalent carbon deposit / rate for each cylinder. The actual carbon deposit amount / rate of each cylinder is obtained by subtracting the initial equivalent carbon deposit amount / rate of each cylinder from the carbon deposit amount / rate of each cylinder mentioned in this cycle.

2. The method for determining the amount of carbon deposits in an injector as described in claim 1, characterized in that, The determination of injector carbon deposits based on the overlap between the injection advance angle and injection duration angle of each cylinder in this cycle and the injection advance angle and injection duration angle of each cylinder, the cyclic injection quantity, and the rail pressure status includes the following steps: The fuel injector carbon deposit determination flag B=1 when all five of the following conditions are met; otherwise, the fuel injector carbon deposit determination flag B=0. The five conditions are as follows: (1) Determining carbon deposits in fuel injectors: enable C=1; (2) Injector fault flag D=0; When there is an open circuit fault or short circuit fault in any cylinder of the engine, the injector fault flag D=1. (3) The fuel supply and injection overlap flag E=0; when the fuel supply advance angle and fuel supply duration angle of each cylinder overlap with the fuel injection advance angle and fuel injection duration angle of each cylinder, the fuel supply and injection overlap flag E=1. (4) Cyclic injection quantity flag F=0; When the cyclic injection quantity of any cylinder of the engine is less than the cyclic injection quantity threshold, the cyclic injection quantity flag F=1; (5) Rail pressure status flag G = 0; when the absolute value of the rail pressure control deviation exceeds the unreasonable threshold value of the rail pressure control deviation or the absolute value of the rail pressure fluctuation exceeds the unreasonable threshold value of the rail pressure fluctuation for a period exceeding the duration threshold value, the rail pressure status flag G = 1; The rail pressure control deviation is the difference between the desired rail pressure and the actual rail pressure, and the rail pressure fluctuation is the difference between the maximum and minimum rail pressure values ​​within a certain period.

3. The method for determining the amount of carbon deposits in an injector as described in claim 1, characterized in that, Based on the rail pressure, intake pressure, injection advance angle and injection duration angle of each cylinder, and total engine running time for this cycle, the engine cylinder pressure, the desired injection pressure difference between each cylinder, and the actual injection pressure difference between each cylinder are calculated, including the following steps: Calculate the midpoint of the injection advance angle based on the injection advance angle and injection duration angle of each cylinder. ； in, The midpoint of the fuel injection advance angle. The injection advance angle for each cylinder, The injection duration angle for each cylinder; Calculate the cylinder pressure correction factor: ； in, This is the cylinder pressure correction factor. This refers to the engine cylinder compression ratio. The adiabatic index, This is the midpoint of the fuel injection advance angle; Calculate the engine cylinder pressure: ； in, This refers to the pressure inside the engine cylinder. This is the cylinder pressure correction factor. This is a correction factor for cylinder leakage characteristics. , Total engine running time To accompany the total engine running time The pulse spectrum of the correction coefficient for varying cylinder leakage characteristics. This refers to the intake pressure. Calculate the desired injection pressure difference between each cylinder of the engine: ； in, To achieve the desired injection pressure difference between the cylinders of the engine, For the desired rail pressure, This refers to the pressure inside the engine cylinder. Calculate the actual injection pressure difference between each cylinder of the engine: ； in, This refers to the actual injection pressure difference in the first cylinder of the engine. This refers to the rail pressure of the first cylinder of the engine. This refers to the pressure inside the engine cylinder.

4. The method for determining the amount of carbon deposits in an injector as described in claim 1, characterized in that, Based on the rail pressure, desired rail pressure, common rail fuel temperature, and injection pressure difference between engine cylinders for this cycle, the actual fuel injection quantity for each cylinder is calculated, including the following steps: Calculate the rail pressure drop of each cylinder in the engine: The rail pressure after fuel injection in each cylinder is subtracted from the rail pressure before fuel injection in each cylinder. This is the rail pressure drop of each cylinder. ; Calculate the bulk modulus of fuel based on the desired rail pressure and the fuel temperature inside the common rail: ； in, The bulk modulus of fuel oil. For the desired rail pressure, This refers to the fuel temperature inside the common rail. The pulse spectrum of fuel bulk elastic modulus; Calculate the actual fuel injection quantity for each cylinder based on the pressure drop across the engine's cylinder rails and the bulk modulus of fuel elasticity: ； in, This represents the actual fuel injection quantity of the first cylinder injector in the engine. The bulk modulus of fuel oil. This refers to the rail pressure drop before and after fuel injection at the injector of the first cylinder of the engine. This refers to the high-pressure fuel volume for the common rail system.

5. The method for determining the amount of carbon deposits in an injector as described in claim 1, characterized in that, Based on the actual fuel injection quantity of each cylinder, the cyclic fuel injection quantity, the expected injection pressure difference between each cylinder of the engine, and the actual injection pressure difference between each cylinder of the engine, the carbon deposit quantity / rate of each cylinder is calculated, including the following steps: Calculate the amount / rate of carbon deposits in each cylinder: ； in, The carbon deposit quantity / rate of the fuel injector in the first cylinder of the engine. This represents the actual fuel injection quantity of the first cylinder injector in the engine. This refers to the amount of fuel injected in a cycle. To achieve the desired injection pressure difference between the cylinders of the engine, This represents the actual injection pressure difference in the first cylinder of the engine.

6. The method for determining the amount of carbon deposits in an injector as described in claim 1, characterized in that, After installing a new engine or replacing the fuel injectors, run the initial equivalent carbon deposit test condition, and sequentially perform the previous steps to obtain the initial equivalent carbon deposit amount / rate for each cylinder. The initial equivalent carbon deposit test condition includes: The engine coolant temperature exceeds the coolant temperature threshold. The engine oil temperature exceeds the oil temperature threshold. The engine is maintained at a specific speed, and the engine speed fluctuation does not exceed the speed fluctuation threshold. The engine load is no load; The rail pressure control deviation shall not exceed the rail pressure control deviation threshold. The rail pressure fluctuation does not exceed the rail pressure fluctuation threshold.

7. The method for determining the amount of carbon deposits in an injector as described in claim 1, characterized in that, After a new engine is installed or a new injector is replaced, the initial equivalent carbon deposit test condition is run. The previous steps are executed sequentially to obtain the initial equivalent carbon deposit amount / rate for each cylinder. The calculated initial equivalent carbon deposit amount / rate for each cylinder will be stored in the electronic control unit (ECU).

8. The method for determining the amount of carbon deposits in an injector as described in claim 1, characterized in that, After obtaining the actual carbon deposit amount / rate of each cylinder, the system also includes: when the actual carbon deposit amount / rate of each cylinder in this cycle exceeds the carbon deposit threshold, an alarm and / or torque limiting are triggered.

9. An electronic device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor, when executing the computer program stored in the memory, implements the steps of the method for determining the amount of carbon deposits in an injector as described in any one of claims 1-8.

10. A computer program product, comprising a computer program, characterized in that: When the computer program is executed by the processor, it implements the steps of the method for determining the amount of carbon deposits in an injector as described in any one of claims 1-8.

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