Method, module and device for evaluating the temperature rise performance of a doc

Abstract

The application provides a DOC temperature rise performance evaluation method, module and device, and relates to the technical field of fuel exhaust treatment. The method comprises the following steps: acquiring a theoretical fuel injection amount of a diesel engine; when the diesel engine enters a regeneration mode, controlling the diesel engine to gradually increase the fuel injection amount from zero, and acquiring an actual fuel injection amount when a current temperature before a DPF reaches a target temperature; after the temperature before the DPF is cooled to room temperature, controlling the diesel engine to perform fuel injection treatment according to the actual fuel injection amount, and recording a temperature rise duration when the current temperature before the DPF reaches the target temperature; and evaluating the DOC temperature rise performance of the diesel engine according to the theoretical fuel injection amount, the actual fuel injection amount and the temperature rise duration. The method achieves the purpose of verifying the temperature rise performance of the DOC, avoids the defect that the diesel engine cannot enter an active regeneration function due to insufficient DOC temperature rise capacity, and thus affects normal driving of the vehicle.

Description

Technical Field

[0001] This application relates to the field of fuel exhaust gas treatment technology, and in particular to a method, module, and device for evaluating DOC temperature rise performance. Background Technology

[0002] Currently, to control particulate matter emissions, China VI diesel engines require the use of a Diesel Particulate Filter (DPF) in the aftertreatment system. When carbon particles accumulate to a certain level in the DPF, an Oxidation Catalyst (DOC) is used to increase the exhaust temperature before the DPF, triggering an active regeneration function to remove carbon deposits.

[0003] The China VI emission standard aftertreatment system involves adjustments to the coating, carrier size, and precious metal content / proportion of the DOC (Diesel Oxide) product, all of which can alter the DOC's temperature rise performance. If the DOC's temperature rise performance is poor, the exhaust gas will not reach the target ignition temperature, preventing the vehicle from actively regenerating and affecting normal operation. Therefore, to ensure that new DOC products meet the requirements for active regeneration by the DPF (Diesel Particulate Filter), thorough validation is necessary before product launch. How to validate the DOC's temperature rise performance is the current problem to be solved. Summary of the Invention

[0004] This application provides a method, module, and device for evaluating the temperature rise performance of a DOC (Digital Oxide Canceller), thereby addressing the problem of product verification during the DOC development process in the prior art.

[0005] In a first aspect, this application provides a method for evaluating the temperature rise performance of a diesel engine (DOC), the method being applied to a diesel engine, the method comprising:

[0006] Obtain the theoretical fuel injection quantity of the diesel engine, where the theoretical fuel injection quantity is the estimated amount of fuel injection when the current temperature before the diesel engine's DPF reaches the target temperature.

[0007] When the diesel engine enters regeneration mode, the diesel engine is controlled to gradually increase the fuel injection quantity from zero, and the actual fuel injection quantity when the current temperature before the DPF reaches the target temperature is obtained.

[0008] After the DPF cools to room temperature, the diesel engine is controlled to inject fuel according to the actual injection quantity, and the temperature rise time when the current temperature in front of the DPF reaches the target temperature is recorded.

[0009] The DOC temperature rise performance of a diesel engine is evaluated based on the theoretical injection quantity, the actual injection quantity, and the temperature rise time.

[0010] Optionally, the theoretical fuel injection quantity of the diesel engine can be obtained, including:

[0011] Obtain the specific heat capacity of the exhaust gas, the temperature difference between the current temperature and the target temperature, and the calorific value of the fuel.

[0012] The theoretical fuel injection quantity of a diesel engine is determined based on the specific heat capacity, temperature difference, and calorific value of the exhaust gas.

[0013] Optionally, record the temperature rise time when the current temperature before the DPF reaches the target temperature, including:

[0014] The first moment when the diesel engine performs fuel injection according to the actual injection quantity, and the second moment when the current temperature reaches the target temperature;

[0015] Based on the first and second moments, determine the time it takes for the current temperature to reach the target temperature.

[0016] Optionally, the DOC temperature rise performance of the diesel engine can be evaluated based on the theoretical injection quantity, the actual injection quantity, and the temperature rise time, including:

[0017] The difference between the theoretical injection quantity and the actual injection quantity is used as the deviation parameter;

[0018] The DOC temperature rise performance of the diesel engine was evaluated based on the deviation parameters and the temperature rise time. Both the deviation parameters and the temperature rise time were negatively correlated with the evaluation results.

[0019] Optionally, after recording the time it takes for the current temperature before the DPF to reach the target temperature, the method further includes:

[0020] Obtain the current temperature after DPF, and based on the current temperature after DPF and the target temperature, determine the temperature difference before and after DPF when the current temperature before DPF reaches the target temperature;

[0021] Control the diesel engine to stop fuel injection and obtain the time it takes for the current temperature before the DPF to drop to the temperature drop temperature, where the temperature drop temperature is lower than the target temperature;

[0022] The DOC temperature rise performance of the diesel engine is evaluated based on deviation parameters and temperature rise duration, including:

[0023] The DOC temperature rise performance of the diesel engine was evaluated based on the deviation parameters, temperature rise time, temperature fall time, and the temperature difference before and after the DPF. The temperature fall time was positively correlated with the evaluation results, while the temperature difference before and after the DPF was negatively correlated with the evaluation results.

[0024] Optionally, the DOC temperature rise performance of the diesel engine can be evaluated based on deviation parameters, temperature rise time, temperature fall time, and the temperature difference before and after the DPF, including:

[0025] After cooling to room temperature before the DPF, the diesel engine is controlled to enter regeneration mode under transient cycle conditions, and the diesel engine is controlled to inject fuel according to the actual fuel injection quantity under transient conditions.

[0026] Determine whether the current temperature before the DPF can reach the target temperature, and obtain the transient cycle judgment result;

[0027] The DOC temperature rise performance of the diesel engine is evaluated based on the deviation parameters, temperature rise time, temperature drop time, temperature difference before and after DPF, and transient cycle judgment results.

[0028] Secondly, please provide a DOC temperature rise performance evaluation module, which is applied to diesel engines, and the module includes:

[0029] The calculation module is used to calculate the theoretical fuel injection quantity of the diesel engine. The theoretical fuel injection quantity is the estimated amount of fuel injection when the current temperature before the diesel engine's DPF reaches the target temperature. The theoretical fuel injection quantity of the diesel engine is calculated based on the specific heat capacity, temperature difference, and calorific value of the exhaust gas.

[0030] The acquisition module is used to acquire the specific heat capacity of the exhaust gas, the temperature difference between the current temperature and the target temperature, and the calorific value of the fuel.

[0031] The acquisition module is also used to acquire the actual amount of fuel injected when the current temperature before the DPF reaches the target temperature.

[0032] The acquisition module is also used to record the temperature rise time when the current temperature before the DPF reaches the target temperature;

[0033] The acquisition module is also used to record the temperature drop time when the DPF inlet temperature drops to the temperature drop temperature after the DPF inlet temperature reaches the target temperature and the oil injection stops.

[0034] The acquisition module is also used to record the temperature before the DPF reaches the target temperature, and the temperatures before and after the DPF.

[0035] The control module is used to control the diesel engine to gradually increase the fuel injection quantity from zero when the diesel engine enters the regeneration mode;

[0036] The control module is also used to control the diesel engine to perform fuel injection according to the actual fuel injection quantity after the DPF has cooled to room temperature.

[0037] The control module is also used to control the diesel engine to stop fuel injection when the temperature before the DPF reaches the target temperature.

[0038] The evaluation module is used to evaluate the DOC temperature rise performance of the diesel engine based on the theoretical injection quantity, actual injection quantity, temperature rise time, temperature drop time, DPF inlet temperature, and DPF outlet temperature.

[0039] Thirdly, this application provides an evaluation device for DOC temperature rise performance, comprising:

[0040] Memory;

[0041] processor;

[0042] The memory stores computer-executed instructions;

[0043] The processor executes computer execution instructions stored in the memory to implement the DOC temperature rise performance evaluation method as described in the first aspect and various possible implementations of the first aspect above.

[0044] The method, module, and equipment for evaluating the temperature rise performance of the DOC (Digital Oxide Charge) provided in this application obtain the theoretical fuel injection quantity of the diesel engine; when the diesel engine enters regeneration mode, the fuel injection quantity is gradually increased from zero, and the actual fuel injection quantity when the current temperature before the DPF reaches the target temperature is obtained; after the DPF cools to room temperature, the diesel engine is controlled to inject fuel according to the actual fuel injection quantity, and the temperature rise time when the current temperature before the DPF reaches the target temperature is recorded; the temperature rise performance of the diesel engine's DOC is evaluated based on the theoretical fuel injection quantity, the actual fuel injection quantity, and the temperature rise time. This method avoids the defect that the diesel engine cannot enter the active regeneration function, thus affecting the normal operation of the vehicle, and realizes the verification of the temperature rise performance of the DOC. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A schematic diagram illustrating the scenario of fuel exhaust gas treatment provided in this application;

[0047] Figure 2 Flowchart of the method for evaluating the temperature rise performance of DOC provided in this application Figure 1 ;

[0048] Figure 3 Flowchart of the method for evaluating the temperature rise performance of DOC provided in this application Figure 2 ;

[0049] Figure 4 Flowchart of the method for evaluating the temperature rise performance of DOC provided in this application Figure 3 ;

[0050] Figure 5 A schematic diagram of the structure of the DOC temperature rise performance evaluation device provided in this application;

[0051] Figure 6 A schematic diagram of the structure of the DOC temperature rise performance evaluation device provided in this application. Detailed Implementation

[0052] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0053] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, products, or apparatus.

[0054] In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0055] First, let me explain the terms used in this application:

[0056] An oxidation catalytic converter (Diesel Oxidation Catalyst, hereinafter referred to as "DOC") is installed in the engine's exhaust system. Through an oxidation reaction, it converts gaseous emissions such as HC, CO, and NO in the engine exhaust into NO2 and CO2. The exothermic reaction from HC oxidation is used for the active regeneration of the DPF (Distillation Processor Filter). It is an early product in catalytic converter technology. Its structure is basically the same as a three-way catalytic converter, except for the catalyst coating. It only has oxidation capabilities and no reduction capabilities.

[0057] Diesel Particulate Filter (DPF): A ceramic filter installed in the emission system of a diesel engine to capture particulate matter before it enters the atmosphere. The part of the DPF closest to the DOC (Diesel Oxide Carbon) is the DPF front end; the part of the DPF furthest from the DOC is the DPF rear end.

[0058] The World Harmonized Transient Cycle (WHTC) is a globally recognized automotive emissions testing standard. The WHTC cycle simulates real-world driving conditions under laboratory conditions, using specific speeds and accelerations, to test vehicle emissions and fuel economy. The WHTC cycle includes low-speed, medium-speed, and high-speed phases. This cycle is commonly used as one of the fundamental testing standards for global automotive emissions standards.

[0059] Figure 1 This is a schematic diagram of a fuel exhaust gas treatment scenario provided in an embodiment of this application. Figure 1 As shown, in the China VI aftertreatment system, the DOC device is generally installed in the engine's emission system, and the DOC is set before the DPF, that is, the rear end of the DOC is connected to the front end of the DPF.

[0060] In real-world scenarios, diesel engines emit exhaust gases that enter the DOC (Digital Oxide Catalyst). The DOC catalytically oxidizes the exhaust gases, converting carbon monoxide (CO) and hydrocarbons (HC) into water (H2O) and carbon dioxide (CO2), and NO into NO2. Since the DOC cannot treat particulate matter, it needs to be actively regenerated to allow the carbon particles captured in the DPF (Digital Dioxide Filter) to undergo secondary combustion, thus converting carbon (C) into carbon dioxide (CO2).

[0061] However, when the China VI aftertreatment system optimizes the coating, adjusts the carrier size, and modifies the precious metal content / proportion for DOC products, the temperature rise performance of the DOC will change. If the temperature rise performance of the DOC is poor, the exhaust cannot reach the target ignition temperature, which will prevent the vehicle from actively regenerating, affecting the normal operation of the vehicle. Therefore, to ensure that the new product DOC can meet the requirements of DPF for active regeneration, the DOC needs to be fully verified before use. How to verify the temperature rise performance of the DOC is the problem that needs to be solved.

[0062] To address the aforementioned issues, this application proposes a method for evaluating the temperature rise performance of a Diesel Engine (DOC). This method evaluates the temperature rise performance of the DOC by comparing the predicted and actual injection values ​​of the diesel engine, as well as the heating time of the DOC when the DPF reaches the target temperature. This verifies the temperature rise performance of the DOC and avoids the defect that the diesel engine cannot enter the active regeneration function, thus affecting the normal operation of the vehicle.

[0063] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0064] Figure 2 A flowchart illustrating the method for evaluating the temperature rise performance of DOC provided in this application embodiment. Figure 1 The executing entity in this embodiment can be, for example, the processor of a diesel engine, or a server communicatively connected to the diesel engine. This application does not impose any limitations on this. The evaluation method shown in this embodiment can be applied to different operating conditions; the specific operating condition to which it is applied depends on the actual situation. Figure 2 As shown, the method includes:

[0065] S101. Obtain the theoretical fuel injection quantity of the diesel engine.

[0066] The theoretical injection quantity is the estimated amount of fuel to be injected when the current temperature before the diesel engine's DPF reaches the target temperature.

[0067] When evaluating the temperature rise performance of the engine compartment (DOC), it is necessary to first obtain the engine's theoretical fuel injection quantity. The theoretical fuel injection quantity can be used as an indicator to evaluate the DOC temperature rise performance; for example, the higher the theoretical fuel injection quantity, the more stringent the DOC temperature rise conditions.

[0068] In this step, for example, a thermal energy formula can be used to determine the theoretical fuel injection quantity of the engine, or the corresponding historical fuel injection quantity can be obtained from historical data as the theoretical fuel injection quantity. This application does not impose any limitations on this.

[0069] It is understandable that different operating conditions correspond to different operating temperatures and different exhaust flow rates.

[0070] For example: Operating condition 1 corresponds to an operating temperature of 300℃ and an exhaust flow rate of 460 kg / h; Operating condition 2 corresponds to an operating temperature of 350℃ and an exhaust flow rate of 500 kg / h; Operating condition 3 corresponds to an operating temperature of 370℃ and an exhaust flow rate of 840 kg / h; and Operating condition 4 corresponds to an operating temperature of 410℃ and an exhaust flow rate of 1400 kg / h. Therefore, the theoretical fuel injection quantity obtained for different operating conditions is also different.

[0071] S102. When the diesel engine enters the regeneration mode, control the diesel engine to gradually increase the fuel injection quantity from zero;

[0072] The regeneration mode is divided into passive regeneration mode and active regeneration mode. This embodiment uses active regeneration mode, which is accomplished by active fuel injection from the engine.

[0073] The DOC starts working after the diesel engine enters regeneration mode. After the diesel engine enters regeneration mode, it injects fuel into the DOC to increase the temperature before the DPF, thereby achieving the purpose of fully burning carbon deposits.

[0074] In this step, for example, after the current operating conditions stabilize, the engine can be switched to regeneration mode, fuel injection can be performed manually, and the injection quantity can be gradually adjusted until the temperature before the DPF reaches the set target temperature.

[0075] S103. Obtain the actual fuel injection quantity when the current temperature before DPF reaches the target temperature.

[0076] The current temperature before the DPF refers to the initial temperature before the DPF is heated under the set operating conditions, while the target temperature refers to the final temperature that the DPF needs to reach after heating treatment.

[0077] After obtaining the engine's theoretical fuel injection quantity, it is also necessary to measure the engine's actual fuel injection quantity. This is so that the temperature rise performance of the DOC can be evaluated subsequently based on the actual fuel injection quantity and / or the difference between the actual and theoretical fuel injection quantities.

[0078] For example, the greater the difference between the actual and theoretical fuel injection quantities, the worse the temperature rise performance of the DOC; the smaller the difference between the actual and theoretical fuel injection quantities, the better the temperature rise performance of the DOC.

[0079] In this step, for example, a method can be used to record the fuel injection quantity while observing the temperature. When the temperature before the DPF reaches the target temperature, fuel injection is stopped, and the fuel injection quantity of the engine when the temperature before the DPF reaches the target temperature is recorded, which is the actual fuel injection quantity.

[0080] S104. After the DPF cools to room temperature, control the diesel engine to inject fuel according to the actual injection quantity, and record the temperature rise time when the current temperature in front of the DPF reaches the target temperature.

[0081] Here, room temperature refers to the operating temperature corresponding to the current operating condition. The current temperature before the DPF refers to the initial temperature maintained before the DPF under the set operating conditions, and the target temperature refers to the temperature that the DPF ultimately needs to reach. Temperature rise time refers to the time required for the temperature before the DPF to rise from the current temperature to the target temperature.

[0082] Temperature rise time can also be used as an indicator to evaluate the temperature rise performance of DOC, assuming the actual fuel injection quantity is known. The shorter the temperature rise time, the better the temperature rise performance of DOC.

[0083] In this step, for example, a timer can be used to determine the temperature rise time. The timer starts when the fuel injection begins and stops when the temperature before the DPF reaches the target temperature to obtain the temperature rise time.

[0084] S105. Evaluate the DOC temperature rise performance of the diesel engine based on the theoretical injection quantity, the actual injection quantity, and the temperature rise time.

[0085] The temperature rise time refers to the time required for the temperature before the DPF to rise from the current temperature to the target temperature.

[0086] When evaluating the temperature rise performance of DOC, it is necessary to combine theoretical injection quantity, actual injection quantity, and temperature rise time for multi-dimensional evaluation. The temperature rise performance of DOC is evaluated by comparing the measurement results. For example, the smaller the deviation between theoretical and actual injection quantity, the lower the actual injection quantity, and the shorter the temperature rise time, the better the temperature rise performance of DOC.

[0087] In this step, for example, multiple comprehensive evaluation indicators can be used to evaluate the temperature rise performance of the DOC. Each measured data point is set within a range with good segmentation, and the measured data are combined to obtain the evaluation result of the DOC temperature rise performance.

[0088] The DOC temperature rise performance evaluation method provided in this embodiment obtains the theoretical fuel injection quantity of the diesel engine; when the diesel engine enters regeneration mode, it controls the diesel engine to gradually increase the fuel injection quantity from zero, and obtains the actual fuel injection quantity when the current temperature before the DPF reaches the target temperature; after the DPF cools to room temperature, it controls the diesel engine to inject fuel according to the actual fuel injection quantity, and records the temperature rise time when the current temperature before the DPF reaches the target temperature; based on the theoretical fuel injection quantity, the actual fuel injection quantity, and the temperature rise time, the DOC temperature rise performance of the diesel engine is evaluated. This method avoids the defect that the diesel engine cannot enter the active regeneration function, thus affecting the normal operation of the vehicle, and realizes the verification process of DOC temperature rise performance.

[0089] Figure 3 A flowchart illustrating the method for evaluating the temperature rise performance of DOC provided in this application embodiment. Figure 2 .like Figure 3 As shown, in this embodiment... Figure 2 Based on the embodiments, the evaluation method for DOC temperature rise performance is described in detail. The evaluation method for DOC temperature rise performance shown in this embodiment includes:

[0090] S201. Obtain the specific heat capacity of the exhaust gas, the temperature difference between the current temperature and the target temperature, and the calorific value of the fuel.

[0091] During fuel injection, the engine produces exhaust gases. Since fuel injection is essentially a heating process that utilizes the exothermic oxidation of DOC (dioxide, carbon dioxide), the exhaust gases from the DOC outlet are also heated during fuel injection.

[0092] This step allows us to obtain the specific heat capacity of the exhaust gas, the temperature difference between the current temperature and the target temperature, and the calorific value of the fuel, so that we can subsequently calculate the theoretical fuel injection quantity of the engine based on the above data.

[0093] S202. Determine the theoretical fuel injection quantity of the diesel engine based on the specific heat capacity, temperature difference, and calorific value of the exhaust gas.

[0094] Theoretical fuel injection quantity is an indicator for evaluating DOC temperature rise conditions. For example, the higher the theoretical fuel injection quantity, the more stringent the DOC temperature rise conditions.

[0095] The theoretical fuel injection quantity of an engine can be determined using the following formula:

[0096] Q = cm1Δt;

[0097] Q = m2q.

[0098] Where Q is the heat generated by the engine when it performs fuel injection when the DPF temperature reaches the target temperature, which is also the heat required for the exhaust gas to reach the target temperature; c is the specific heat capacity of the exhaust gas; m1 is the mass of the exhaust gas; Δt is the temperature difference between the current temperature and the target temperature; m2 is the mass of fuel consumed by the engine when it performs fuel injection; and q is the thermal energy of the fuel.

[0099] As shown in the formula above, the specific heat capacity of exhaust gas is fixed and known. During the evaluation test, the target operating condition is determined in advance, and the target temperature can be determined based on this condition. Therefore, the temperature difference between the current temperature and the target temperature is also known. There is a correlation between the type of fuel and its thermal energy; when the type of fuel is fixed, its thermal energy is also known.

[0100] Since the heat generated in the two formulas above is the same, there are only two unknowns: the mass of the exhaust gas (m1) and the mass of the fuel (m2). Therefore, the mass of the exhaust gas and the mass of the fuel can be determined using these two formulas. This mass of fuel is the theoretical fuel injection quantity to be obtained in this step.

[0101] S203. When the diesel engine enters regeneration mode, control the diesel engine to gradually increase the fuel injection quantity from zero.

[0102] S204: Actual fuel injection quantity when the current temperature before obtaining the DPF reaches the target temperature.

[0103] S205. When the temperature before the DPF reaches room temperature, control the diesel engine to inject fuel according to the actual injection quantity.

[0104] Steps S203-S205 are similar to steps 102-S104 above, and will not be repeated here.

[0105] S206. Obtain the first moment when the diesel engine performs fuel injection according to the actual injection quantity, and the second moment when the current temperature reaches the target temperature.

[0106] The first moment is when the diesel engine begins fuel injection. The second moment is when the temperature before the DPF reaches the target temperature.

[0107] After obtaining the first and second time points, the temperature rise performance of the DOC can be evaluated based on the difference between the first and second time points.

[0108] In this step, for example, a timer and a temperature sensor can be used to determine the first and second moments. The timer records this moment when the diesel engine begins fuel injection. The actual temperature before the DPF is determined by the temperature sensor and compared with the target temperature to determine if the target temperature has been reached. When the target temperature is reached, this moment is recorded; this moment is the second moment: the moment when the temperature before the DPF reaches the target temperature.

[0109] S207. Based on the first and second moments, determine the time it takes for the current temperature to reach the target temperature.

[0110] The temperature rise time refers to the difference between the first and second moments.

[0111] Understandably, if the temperature rise time before the DPF is long, it indicates that the heating efficiency of the DOC is low; if the temperature rise time before the DPF is short, it indicates that the heating efficiency of the DOC is high, and it can perform secondary combustion of carbon particles in the aftertreatment system in a short time when the diesel engine is in normal use.

[0112] Therefore, this step determines the temperature rise time for the DPF to reach the target temperature by taking the first moment when the DPF inlet temperature is the operating temperature and the engine starts to perform fuel injection, and the second moment when the DPF inlet temperature reaches the target temperature. The purpose of this step is to subsequently evaluate the heating efficiency of the DOC based on the temperature rise time.

[0113] S208. The difference between the theoretical injection quantity and the actual injection quantity is used as the deviation parameter.

[0114] The deviation parameter refers to the difference between the theoretical fuel injection quantity and the actual fuel injection quantity.

[0115] If this deviation parameter is large, it indicates a significant discrepancy between the fuel injection quantity calculated by the engine power theory and the actual required fuel injection quantity. In this case, the actual situation might be as follows: an abnormality exists during the DOC heating process, leading to lower DOC heating efficiency. Conversely, if this deviation parameter is small, it indicates a smaller discrepancy between the fuel injection quantity calculated by the engine power theory and the actual required fuel injection quantity. In other words, the DOC is being heated according to its estimated capacity, and its heating efficiency meets the standard value. Understandably, the purpose of this step is to subsequently evaluate the DOC's temperature rise performance based on this deviation parameter.

[0116] In this step, the measured actual fuel injection quantity can be input into the system using a preset command. The system will then automatically compare the actual fuel injection quantity under this operating condition with the theoretical fuel injection quantity to obtain the deviation parameter. Alternatively, the deviation parameter can be calculated manually by recording and calculating the data. This application does not impose any limitations on this method.

[0117] S209. Evaluate the DOC temperature rise performance of the diesel engine based on the deviation parameters and temperature rise time.

[0118] Once the deviation parameters and temperature rise time are obtained, these parameters can be used as indicators to evaluate the temperature rise performance of the DOC.

[0119] Both the deviation parameter and the temperature rise time are negatively correlated with the evaluation results. That is, the smaller the deviation parameter, the better the temperature rise performance of the DOC; the larger the deviation parameter, the worse the temperature rise performance of the DOC. The shorter the temperature rise time, the better the temperature rise performance of the DOC; the longer the temperature rise time, the worse the temperature rise performance of the DOC.

[0120] It is understood that the evaluation method shown in this embodiment is only an evaluation method under a single operating condition. In practical applications, evaluation indicators under a single operating condition can be used to evaluate the DOC temperature rise performance, or evaluation indicators under multiple operating conditions can be used to evaluate the DOC temperature rise performance.

[0121] When using evaluation indicators under multiple operating conditions to evaluate the DOC temperature rise performance, steps S201-S208 above can be performed for each operating condition to obtain the deviation parameters and temperature rise duration corresponding to each operating condition. Then, based on the deviation parameters and temperature rise duration corresponding to multiple operating conditions, the DOC temperature rise performance of the diesel engine can be comprehensively evaluated.

[0122] The DOC temperature rise performance evaluation method provided in this embodiment determines the engine's theoretical fuel injection quantity by combining the specific heat capacity of exhaust gas, the temperature difference before the DPF, and the calorific value of fuel, thus making the determined theoretical fuel injection quantity more accurate. Furthermore, the difference between the actual fuel injection quantity and the theoretical fuel injection quantity is used as the evaluation index for DOC temperature rise performance, which can more accurately reflect the quality of DOC temperature rise performance. At the same time, the evaluation also fully considers the temperature rise time, making the evaluation more authoritative. This method avoids the defect of diesel engines being unable to enter the active regeneration function, thus affecting the normal operation of the vehicle, and realizes the verification process of DOC temperature rise performance.

[0123] Figure 4 A flowchart illustrating the method for evaluating the temperature rise performance of DOC provided in this application embodiment. Figure 3 In this embodiment, the evaluation of DOC temperature rise performance is based not only on deviation parameters and temperature rise duration, but also on parameters such as temperature drop duration and temperature rise under instantaneous cyclic conditions. The execution timing of this embodiment can be, for example, after recording the temperature rise duration when the current temperature before DPF reaches the target temperature, or it can be after... Figure 3 A detailed description of step S209 in the embodiments. This application does not impose any limitations.

[0124] like Figure 4 As shown, in this embodiment... Figure 3 Based on the embodiments, the evaluation method for DOC temperature rise performance is further explained. The evaluation method for DOC temperature rise performance shown in this embodiment includes:

[0125] S301: Obtain the current temperature after the DPF, and based on the current temperature after the DPF and the target temperature, determine the temperature difference before and after the DPF when the current temperature before the DPF reaches the target temperature.

[0126] The temperature after the DPF refers to the temperature at the back end of the DPF. Under normal circumstances, the temperature after the DPF is basically the same as the temperature before the DPF.

[0127] However, in real-world scenarios, the following situation exists: when the DOC has poor temperature rise performance and requires excessive fuel injection, some fuel that cannot react in the DOC in time enters the DPF, causing the temperature after the DPF to rise rapidly.

[0128] Therefore, the purpose of obtaining the current temperature after the DPF in this step is to determine whether there is a fuel leak in the DOC. In this step, the temperature after the DPF can be obtained using a temperature sensor installed after the DPF. The temperature obtained here is the current temperature after the DPF when the temperature before the DPF reaches the target temperature, thus providing a more realistic reflection of the actual situation.

[0129] Once the current temperature after obtaining the DPF is obtained, since the temperature before the DPF has reached the target temperature, the temperature difference before and after the DPF can be determined based on the current temperature after the DPF and the target temperature.

[0130] S302: Controls the diesel engine to stop fuel injection and obtains the duration of temperature drop when the current temperature before the DPF decreases to the temperature drop temperature.

[0131] Specifically, when the target temperature is 550℃, the temperature drop can be set to, for example, 400℃. If the temperature before the DPF reaches the target temperature, it indicates that the current temperature before the DPF is sufficient to allow the carbon particles to undergo secondary combustion, converting C into carbon dioxide (CO2). In this case, fuel injection is no longer necessary.

[0132] Understandably, when no oil injection is performed, the temperature before the DPF will decrease normally over time. At this point, the time it takes for the current temperature before the DPF to drop to the desired temperature can be obtained.

[0133] The temperature drop time obtained in this step can also be used to evaluate the temperature rise performance of the DOC. It's understandable that when the DOC is heated until the DPF reaches the target temperature, the secondary combustion of carbon particles requires a certain amount of time. Therefore, the DPF needs to maintain a stable temperature for this secondary combustion. Since both the DOC and DPF are in the same space, the temperature drop time can implicitly indicate the DOC's insulation performance; a longer temperature drop time indicates better insulation performance, and a shorter temperature drop time indicates poorer insulation performance.

[0134] S303: After cooling to room temperature before the DPF, the diesel engine is controlled to enter regeneration mode under transient cycle conditions, and the diesel engine is controlled to inject fuel according to the actual fuel injection quantity under transient conditions.

[0135] The operating conditions of a diesel engine are generally divided into steady-state conditions and transient cycles. Since the above experiments were all conducted under steady-state conditions, it is also necessary to collect data on the diesel engine under transient cycle conditions to determine the performance of the DOC under transient cycle conditions.

[0136] Once the DPF inlet temperature has cooled to the operating temperature, the diesel engine can be controlled to inject fuel according to the actual injection quantity under transient cycle conditions.

[0137] S304: Determine whether the current temperature before the DPF can reach the target temperature, and obtain the transient cycle judgment result.

[0138] In this process, after the diesel engine is injected with fuel according to the actual amount of fuel injected under transient cycle conditions, it can be determined whether the temperature before the DPF under transient cycle conditions can reach the target temperature, that is, whether the actual amount of fuel injected under transient cycle conditions meets the conditions for secondary combustion of carbon particles.

[0139] Understandably, if the target temperature cannot be reached under transient cycling conditions, it indicates that the temperature rise performance of the DOC under transient cycling conditions is insufficient; if the target temperature can be reached under transient cycling conditions, it indicates that the temperature rise performance of the DOC under transient cycling conditions meets the standard. The evaluation results of the temperature rise performance of the DOC under transient cycling conditions can be used as an evaluation index of the temperature rise performance of the DOC.

[0140] S305: Evaluate the DOC temperature rise performance of the diesel engine based on deviation parameters, temperature rise time, temperature drop time, temperature difference before and after DPF, and transient cycle judgment results.

[0141] When evaluating the temperature rise performance of a DOC (Digital Oscillator), it is necessary to first obtain the deviation parameters, temperature rise duration, temperature fall duration, temperature difference before and after the DPF (Digital Power Factor), and transient cycle judgment results. These parameters can serve as indicators for evaluating the DOC's temperature rise performance. The temperature fall duration is positively correlated with the evaluation results, while the temperature difference before and after the DPF is negatively correlated. For example, a shorter temperature fall duration indicates poorer temperature rise performance of the DOC, while a longer duration indicates better performance. Similarly, a smaller temperature difference before and after the DPF indicates better performance, while a larger difference indicates poorer performance.

[0142] Specific evaluation methods may include: using a multi-indicator comprehensive evaluation method to assess DOC performance, specifying scoring criteria for each indicator, scoring the actual value of each indicator, and determining the weights for each indicator. Finally, the scores of each indicator are weighted and combined, and the result is the comprehensive evaluation value of the multi-indicator evaluation, which is the assessment of DOC temperature rise performance.

[0143] The DOC temperature rise performance evaluation method provided in this embodiment uses the temperature drop time of the DOC from the target temperature to the temperature drop temperature and the temperature rise under instantaneous cyclic conditions as evaluation indicators, thereby making the evaluation of the DOC temperature rise performance more accurate.

[0144] Figure 5 This is a schematic diagram of the DOC temperature rise performance evaluation module provided in this embodiment. This module is applied to a diesel engine. Figure 5 As shown, the DOC temperature rise performance evaluation module 300 provided in this application includes:

[0145] The calculation module 301 is used to calculate the theoretical fuel injection quantity of the diesel engine. The theoretical fuel injection quantity is the estimated amount of fuel injection when the current temperature before the diesel engine's DPF reaches the target temperature. The theoretical fuel injection quantity of the diesel engine is calculated based on the specific heat capacity, temperature difference, and calorific value of the exhaust gas.

[0146] The acquisition module 302 is used to acquire the specific heat capacity of the exhaust gas, the temperature difference between the current temperature and the target temperature, and the calorific value of the fuel.

[0147] The acquisition module 302 is also used to acquire the actual amount of fuel injected when the current temperature before the DPF reaches the target temperature;

[0148] The acquisition module 302 is also used to record the temperature rise time when the current temperature before the DPF reaches the target temperature;

[0149] The acquisition module 302 is also used to record the temperature drop time when the DPF inlet temperature drops to the temperature drop temperature after the DPF inlet temperature reaches the target temperature and the oil injection stops.

[0150] The acquisition module 302 is also used to record the temperature before the DPF reaches the target temperature, and the temperature before and after the DPF.

[0151] Control module 303 is used to control the diesel engine to gradually increase the fuel injection quantity from zero when the diesel engine enters the regeneration mode;

[0152] The control module 303 is also used to control the diesel engine to perform fuel injection according to the actual fuel injection quantity after the DPF has cooled to room temperature.

[0153] The control module 303 is also used to control the diesel engine to stop fuel injection when the temperature before the DPF reaches the target temperature.

[0154] Evaluation module 304 is used to evaluate the DOC temperature rise performance of the diesel engine based on theoretical injection quantity, actual injection quantity, temperature rise time, temperature drop time, DPF inlet temperature and DPF outlet temperature.

[0155] Figure 6 A schematic diagram of the structure of the DOC temperature rise performance evaluation device provided in this application. Figure 6 As shown, the DOC temperature rise performance evaluation device 400 provided in this application includes: a receiver 401, a transmitter 402, a processor 403, and a memory 404.

[0156] Receiver 401 is used to receive instructions and data;

[0157] Transmitter 402 is used to send commands and data;

[0158] Memory 404 is used to store instructions executed by the computer;

[0159] Processor 403 is used to execute computer execution instructions stored in memory 404 to implement the various steps of the DOC temperature rise performance evaluation method in the above embodiments. For details, please refer to the relevant descriptions in the foregoing embodiments of the DOC temperature rise performance evaluation method.

[0160] Optionally, the memory 404 can be either standalone or integrated with the processor 403.

[0161] When the memory 404 is set up independently, the electronic device also includes a bus for connecting the memory 404 and the processor 403.

[0162] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the DOC temperature rise performance evaluation method performed by the aforementioned DOC temperature rise performance evaluation device.

[0163] It will be understood by those skilled in the art that all or some of the steps, systems, or apparatuses disclosed above, and their functional modules / units, can be implemented as software, firmware, hardware, or suitable combinations thereof. In hardware implementations, the division between functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed collaboratively by several physical components. Some or all physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit (ASIC). Such software may be distributed on a computer-readable medium, which may include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and can be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0164] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0165] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for evaluating the temperature rise performance of a DOC (Digital Oxide Canopy), characterized in that, Applied to diesel engines, including: Obtain the theoretical fuel injection quantity of the diesel engine, where the theoretical fuel injection quantity is the estimated amount of fuel injection when the current temperature before the diesel engine's DPF reaches the target temperature. When the diesel engine enters regeneration mode, the diesel engine is controlled to gradually increase the fuel injection quantity from zero, and the actual fuel injection quantity when the current temperature before the DPF reaches the target temperature is obtained. After the DPF cools to room temperature, the diesel engine is controlled to inject fuel according to the actual injection quantity, and the temperature rise time when the current temperature in front of the DPF reaches the target temperature is recorded. The DOC temperature rise performance of a diesel engine is evaluated based on the theoretical injection quantity, the actual injection quantity, and the temperature rise time.

2. The method according to claim 1, characterized in that, The process of obtaining the theoretical fuel injection quantity of the diesel engine includes: Obtain the specific heat capacity of the exhaust gas, the temperature difference between the current temperature and the target temperature, and the calorific value of the fuel. The theoretical fuel injection quantity of a diesel engine is determined based on the specific heat capacity, temperature difference, and calorific value of the exhaust gas.

3. The method according to claim 2, characterized in that, The temperature rise time when the current temperature before the DPF is recorded reaches the target temperature includes: The first moment when the diesel engine performs fuel injection according to the actual injection quantity, and the second moment when the current temperature reaches the target temperature; Based on the first and second moments, determine the time it takes for the current temperature to reach the target temperature.

4. The method according to claim 1, characterized in that, The evaluation of the DOC temperature rise performance of the diesel engine is based on the theoretical injection quantity, the actual injection quantity, and the temperature rise time, including: The difference between the theoretical injection quantity and the actual injection quantity is used as the deviation parameter; The DOC temperature rise performance of the diesel engine was evaluated based on the deviation parameters and the temperature rise time. Both the deviation parameters and the temperature rise time were negatively correlated with the evaluation results.

5. The method according to claim 4, characterized in that, After recording the temperature rise time when the current temperature before the DPF reaches the target temperature, the method further includes: Obtain the current temperature after DPF, and based on the current temperature after DPF and the target temperature, determine the temperature difference before and after DPF when the current temperature before DPF reaches the target temperature; Control the diesel engine to stop fuel injection and obtain the time it takes for the current temperature before the DPF to drop to the temperature drop temperature, where the temperature drop temperature is lower than the target temperature; The evaluation of the DOC temperature rise performance of the diesel engine based on the deviation parameter and the temperature rise duration includes: The DOC temperature rise performance of the diesel engine was evaluated based on the deviation parameters, temperature rise time, temperature fall time, and the temperature difference before and after the DPF. The temperature fall time was positively correlated with the evaluation results, while the temperature difference before and after the DPF was negatively correlated with the evaluation results.

6. The method according to claim 5, characterized in that, The evaluation of the DOC temperature rise performance of the diesel engine is based on deviation parameters, temperature rise time, temperature fall time, and the temperature difference before and after the DPF, including: After cooling to room temperature before the DPF, the diesel engine is controlled to enter regeneration mode under transient cycle conditions, and the diesel engine is controlled to inject fuel according to the actual fuel injection quantity under transient conditions. Determine whether the current temperature before the DPF can reach the target temperature, and obtain the transient cycle judgment result; The DOC temperature rise performance of the diesel engine is evaluated based on the deviation parameters, temperature rise time, temperature drop time, temperature difference before and after DPF, and transient cycle judgment results.

7. A module for evaluating the temperature rise performance of a DOC (Digital Oxide Canopy), characterized in that, Applied to diesel engines, the module includes: The calculation module is used to calculate the theoretical fuel injection quantity of the diesel engine. The theoretical fuel injection quantity is the estimated amount of fuel injection when the current temperature before the diesel engine's DPF reaches the target temperature. The theoretical fuel injection quantity of the diesel engine is calculated based on the specific heat capacity, temperature difference, and calorific value of the exhaust gas. The acquisition module is used to acquire the specific heat capacity of the exhaust gas, the temperature difference between the current temperature and the target temperature, and the calorific value of the fuel. The acquisition module is also used to acquire the actual amount of fuel injected when the current temperature before the DPF reaches the target temperature. The acquisition module is also used to record the temperature rise time when the current temperature before the DPF reaches the target temperature; The acquisition module is also used to record the temperature drop time when the DPF inlet temperature drops to the temperature drop temperature after the DPF inlet temperature reaches the target temperature and the oil injection stops. The acquisition module is also used to record the temperature before the DPF reaches the target temperature, and the temperatures before and after the DPF. The control module is used to control the diesel engine to gradually increase the fuel injection quantity from zero when the diesel engine enters the regeneration mode; The control module is also used to control the diesel engine to perform fuel injection according to the actual fuel injection quantity after the DPF has cooled to room temperature. The control module is also used to control the diesel engine to stop fuel injection when the temperature before the DPF reaches the target temperature. The evaluation module is used to evaluate the DOC temperature rise performance of the diesel engine based on the theoretical injection quantity, actual injection quantity, temperature rise time, temperature drop time, DPF inlet temperature, and DPF outlet temperature.

8. A device for evaluating the temperature rise performance of a DOC (Digital Oxide Canopy), characterized in that, include: Memory; processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory to implement the DOC temperature rise performance evaluation method as described in any one of claims 1-6.

Images