Method for measuring DOC conversion efficiency of hydrogen internal combustion engine and related device

Abstract

The invention provides a hydrogen internal combustion engine DOC conversion efficiency measuring method and a related device, and relates to the field of engines. According to the scheme provided by the embodiment of the invention, for measuring the DOC conversion efficiency of a hydrogen internal combustion engine, when it is judged that an oxidation catalyst is in an enabling working condition, whether the hydrogen concentration in the oxidation catalyst is within a preset range or not is judged; if the theoretical conversion energy is within the preset range, actual conversion energy is obtained through calculation based on the exhaust gas specific heat capacity of the engine, the air inflow of the oxidation catalyst and the front-back temperature difference of the oxidation catalyst, and the ratio of the actual conversion energy to the theoretical conversion energy serves as the conversion efficiency of the oxidation catalyst; according to the scheme, the enabling working condition and the hydrogen concentration serve as limiting conditions in the DOC conversion efficiency measurement process according to the characteristics of the hydrogen internal combustion engine, and the reliability of the measurement result of the DOC conversion efficiency of the hydrogen internal combustion engine is improved.

Description

Technical Field

[0001] The present invention relates to the field of engine technology, and in particular to a method for measuring DOC conversion efficiency of a hydrogen internal combustion engine and a related device. Background Art

[0002] Hydrogen internal combustion engines use hydrogen as fuel. Compared to internal combustion engines using fuels like diesel and gasoline, hydrogen engines do not use carbon-containing fuels and therefore theoretically produce no greenhouse gases or pollutants such as carbon dioxide, particulate matter, carbon monoxide, and hydrocarbons, making them a clean power system. However, hydrogen combustion is not as stable as diesel or gasoline. Incomplete combustion or misfires can cause the engine to emit large amounts of unburned hydrogen, which carries a high risk of explosion (at normal temperature and pressure, hydrogen concentrations in air between 4% and 70% are explosive). Therefore, it is necessary to accurately and promptly diagnose abnormal hydrogen emissions, restrict engine operation to prevent accidents, and alert the user to promptly perform maintenance.

[0003] The after-treatment system refers to the exhaust purification system located at the exhaust end of the engine, which generally includes DOC and SCR. It usually uses a catalyst to cause a series of reactions in the exhaust gas burned by the engine, thereby removing harmful pollutants or particulate matter in the exhaust gas or converting them into harmless water, nitrogen, and carbon dioxide. For hydrogen internal combustion engines, on the one hand, there will still be a small amount of nitrogen oxides emitted, which react in the SCR. On the other hand, under transient conditions, cold start, misfire and other conditions, there may be hydrogen emissions that are not burned in the cylinder (hydrogen is not an air pollutant, but it is a dangerous explosive). The DOC is needed to oxidize the hydrogen to further reduce hydrogen leakage in the exhaust gas. The conversion efficiency of DOC is directly related to the reliability of the after-treatment system. In the existing scheme, the conversion efficiency of DOC of hydrogen internal combustion engines is usually diagnosed by the diagnosis method of DOC conversion efficiency of diesel engines. However, the applicant has found through research that the DOC conversion efficiency calculated by this method is not reliable. Therefore, how to accurately calculate the conversion efficiency of DOC is one of the technical problems that technicians in this field urgently need to solve. Summary of the Invention

[0004] In view of this, an embodiment of the present invention provides a method and related device for measuring the DOC conversion efficiency of a hydrogen internal combustion engine, so as to achieve accurate measurement of the DOC conversion efficiency of a hydrogen internal combustion engine.

[0005] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0006] A method for measuring DOC conversion efficiency of a hydrogen internal combustion engine, comprising:

[0007] Determining whether the oxidation catalyst is in an enabled operating condition;

[0008] When the oxidation catalyst is in an enabled state, obtaining a hydrogen concentration in the oxidation catalyst;

[0009] Determining whether the hydrogen concentration is within a preset range;

[0010] When the hydrogen concentration is within a preset range, obtaining the exhaust gas specific heat capacity of the engine, the intake air volume of the oxidation catalyst, and the temperature difference between the front and rear of the oxidation catalyst;

[0011] Calculating actual conversion energy based on the exhaust gas specific heat capacity of the engine, the air intake amount of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst;

[0012] obtaining theoretical conversion energy based on the injection amount of the hydrogen;

[0013] The ratio of the actual conversion energy to the theoretical conversion energy is taken as the conversion efficiency of the oxidation catalyst.

[0014] Optionally, in the above-mentioned method for measuring the DOC conversion efficiency of a hydrogen internal combustion engine, the actual conversion energy is calculated based on the exhaust gas specific heat capacity of the engine, the intake air volume of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst, including:

[0015] The product of the exhaust gas specific heat capacity of the engine, the air intake amount of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst is taken as the actual conversion energy.

[0016] Optionally, in the above-mentioned method for measuring the DOC conversion efficiency of a hydrogen internal combustion engine, determining whether the oxidation catalyst is in an enabled operating condition includes:

[0017] determining whether an intake air volume of the oxidation catalyst is greater than a preset intake air volume, whether the oxidation catalyst is in a stable operating state, and whether a temperature before the oxidation catalyst is greater than a preset temperature;

[0018] When the intake air amount of the oxidation catalyst is greater than a preset intake air amount, the oxidation catalyst is in a stable operating condition, and the temperature before the oxidation catalyst is greater than a preset temperature, it is determined that the oxidation catalyst is in an enabled operating condition.

[0019] Optionally, in the above-mentioned method for measuring the DOC conversion efficiency of a hydrogen internal combustion engine, when it is determined that the hydrogen concentration is not within a preset range, the method further includes:

[0020] adjusting the hydrogen concentration in the oxidation catalyst by adjusting the target parameter until the hydrogen concentration in the oxidation catalyst is within a preset range;

[0021] The target parameters include any one or more of excess air ratio, post-injection injection amount, ignition advance angle, EGR flow rate and hydrogen injection timing.

[0022] Optionally, in the above-mentioned method for measuring the DOC conversion efficiency of a hydrogen internal combustion engine, adjusting the hydrogen concentration in the oxidation catalyst by adjusting the target parameter includes:

[0023] The target parameter is adjusted on the basis of maintaining the oxidation catalyst in the enabled operating condition to adjust the hydrogen concentration in the oxidation catalyst to within a preset range.

[0024] Optionally, in the above-mentioned method for measuring the DOC conversion efficiency of a hydrogen internal combustion engine, adjusting the target parameter on the basis of maintaining the oxidation catalyst in the enabling operating condition includes:

[0025] A target parameter in the target parameter group is selected as an adjustment object based on a descending priority order, the hydrogen concentration in the oxidation catalyst is adjusted, and it is determined that the oxidation catalyst is out of an enabling operating condition during the adjustment process. When the oxidation catalyst is out of the enabling operating condition, the adjustment object is returned to the previous adjustment step, and a target parameter with the next highest priority in the target parameter group is selected as the adjustment object. The hydrogen concentration in the oxidation catalyst is continuously adjusted until the hydrogen concentration in the oxidation catalyst is adjusted to within a preset range.

[0026] Optionally, in the above-mentioned method for measuring the DOC conversion efficiency of a hydrogen internal combustion engine, after taking the ratio of the actual conversion energy to the theoretical conversion energy as the conversion efficiency of the oxidation catalyst, the method further includes:

[0027] Determining whether the conversion efficiency is less than a preset conversion efficiency;

[0028] When the conversion efficiency is less than the preset conversion efficiency, a hydrogen leakage diagnosis strategy is executed.

[0029] A device for measuring DOC conversion efficiency of a hydrogen internal combustion engine, comprising:

[0030] An operating condition judgment unit, used to judge whether the oxidation catalyst is in an enabled operating condition;

[0031] a hydrogen concentration acquisition unit, configured to acquire the hydrogen concentration in the oxidation catalyst when the oxidation catalyst is in an enabled operating condition;

[0032] a concentration judging unit, configured to judge whether the hydrogen concentration is within a preset range;

[0033] a parameter acquisition unit, configured to acquire the exhaust gas specific heat capacity of the engine, the intake air volume of the oxidation catalyst, and the temperature difference between the front and rear of the oxidation catalyst when the hydrogen concentration is within a preset range;

[0034] an actual conversion energy calculation unit, configured to calculate the actual conversion energy based on the exhaust gas specific heat capacity of the engine, the intake air volume of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst;

[0035] a theoretical conversion energy acquisition unit, configured to acquire theoretical conversion energy based on the injection amount of the hydrogen;

[0036] The conversion efficiency calculation unit is configured to use the ratio of the actual conversion energy to the theoretical conversion energy as the conversion efficiency of the oxidation catalyst.

[0037] An electronic device, comprising:

[0038] at least one processing device and a storage device connected to the processing device, wherein:

[0039] The storage device is used to store computer programs;

[0040] The processing device is used to execute the computer program so that the electronic device can implement any one of the above-mentioned methods for measuring the DOC conversion efficiency of a hydrogen internal combustion engine.

[0041] A car comprises the above electronic device.

[0042] Based on the above technical solution, the above solution provided by the embodiment of the present invention is for measuring the DOC conversion efficiency of a hydrogen internal combustion engine. When it is determined that the oxidation catalyst is in an enabled condition, it is determined whether the hydrogen concentration in the oxidation catalyst is within a preset range. If it is within the preset range, the actual conversion energy is calculated based on the specific heat capacity of the engine's exhaust gas, the intake amount of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst. The ratio of the actual conversion energy to the theoretical conversion energy is used as the conversion efficiency of the oxidation catalyst. This solution uses the enabling condition and the hydrogen concentration as limiting conditions in the DOC conversion efficiency measurement process based on the characteristics of the hydrogen internal combustion engine, thereby improving the reliability of the measurement results of the DOC conversion efficiency of the hydrogen internal combustion engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0044] Figure 1 Schematic diagram of the flow chart of the method for measuring the DOC conversion efficiency of a hydrogen internal combustion engine disclosed in an embodiment of the present application;

[0045] Figure 2 This is a schematic structural diagram of a device for measuring DOC conversion efficiency of a hydrogen internal combustion engine disclosed in an embodiment of the present application;

[0046] Figure 3 This is a structural diagram of the automobile's after-treatment system. DETAILED DESCRIPTION

[0047] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0048] This application discloses a method for measuring the DOC conversion efficiency of a hydrogen internal combustion engine. Figure 1 , the method may include:

[0049] Step S101: Determine whether the oxidation catalyst is in an enabled state.

[0050] Data related to the operating status of the oxidation catalyst is collected in real time through various sensors installed on the hydrogen internal combustion engine, as well as through the ECU, VCU, etc. For example, a temperature sensor monitors the inlet and outlet temperatures of the oxidation catalyst, and a pressure sensor obtains pressure data within the oxidation catalyst. This data is then combined with engine operating parameters (such as speed and load) to comprehensively determine the operating condition of the oxidation catalyst and further determine whether the oxidation catalyst is in a preset enabled operating condition.

[0051] The enabling condition ensures that the oxidation catalyst is in a state where it can normally perform its catalytic function when executing the solution disclosed in this embodiment. Subsequent measurements and calculations are meaningful only under the enabling condition, avoiding inaccurate results under abnormal conditions, thereby ensuring the accuracy and reliability of the entire measurement process.

[0052] In this solution, pre-set conditions are used to determine the enabling condition. These conditions can be customized based on design requirements. For example, they may include the oxidation catalyst reaching a certain operating temperature range (e.g., an inlet temperature between 200°C and 400°C to ensure effective oxidation catalytic reaction) and the engine operating normally (with speed and load within reasonable ranges to prevent abnormal engine operation from affecting the oxidation catalyst's performance). The collected actual data is compared with the pre-set conditions. If all pre-set conditions are met, the oxidation catalyst is determined to be in the enabling condition. In this embodiment, the pre-set conditions may include at least one or more of the following: an intake air volume greater than a pre-set intake air volume, a stable operating condition for the oxidation catalyst, and a temperature in front of the oxidation catalyst greater than a pre-set temperature. In a specific embodiment, when judging whether the oxidation catalyst is in the enabled operating condition, it is specifically judged whether the intake air volume of the oxidation catalyst is greater than a preset intake air volume, whether the oxidation catalyst is in a stable operating condition, and whether the temperature before the oxidation catalyst is greater than a preset temperature. When it is determined that the intake air volume of the oxidation catalyst is greater than the preset intake air volume, the oxidation catalyst is in a stable operating condition, and the temperature before the oxidation catalyst is greater than the preset temperature, it indicates that the oxidation catalyst is in the enabled operating condition.

[0053] Step S102: when the oxidation catalyst is in an enabled state, obtaining the hydrogen concentration in the oxidation catalyst.

[0054] Hydrogen concentration is a key factor affecting the conversion efficiency of oxidation catalysts. Accurately measuring hydrogen concentration provides the foundational data for determining whether it is within a preset range, ensuring that subsequent energy calculations and efficiency assessments are performed under appropriate hydrogen concentration conditions.

[0055] In this embodiment, a high-precision hydrogen concentration sensor can be installed inside the oxidation catalyst or at its inlet and outlet to ensure accurate hydrogen concentration measurement. The sensor collects real-time hydrogen concentration data within the oxidation catalyst and transmits the data to a data processing system. The data processing system filters the collected data to remove noise and interference signals, thereby improving the accuracy and stability of the collected hydrogen concentration.

[0056] Step S103: Determine whether the hydrogen concentration is within a preset range.

[0057] When measuring the conversion efficiency of an oxidation catalyst using the method disclosed in this embodiment, it is necessary to ensure that the oxidation catalyst operates under appropriate hydrogen concentration conditions. Excessively high or low hydrogen concentrations can affect the oxidation catalytic reaction and, in turn, the conversion efficiency measurement results. By determining whether the hydrogen concentration is within a preset range, subsequent measurements and calculations are ensured to be based on reasonable operating conditions.

[0058] In the technical solution disclosed in this embodiment, a reasonable range of hydrogen concentration can be pre-set based on the performance parameters of the oxidation catalyst, the chemical properties of hydrogen, and the operating requirements of the engine. For example, considering the efficiency and safety of the oxidation catalytic reaction, the hydrogen concentration may be set within the range of 2000ppm < H2 < 4000ppm.

[0059] This step compares the actual hydrogen concentration obtained with a preset range. If the actual hydrogen concentration is within the preset range, proceed to the next step. If it is not within the preset range, adjust the engine operating parameters (such as hydrogen injection volume and air intake volume) to bring the hydrogen concentration into the appropriate range before re-measuring.

[0060] Step S104: When the hydrogen concentration is within a preset range, the exhaust gas specific heat capacity of the engine, the air intake volume of the oxidation catalyst, and the temperature difference between the front and rear of the oxidation catalyst are obtained.

[0061] The engine's exhaust gas specific heat capacity, the air intake volume of the oxidation catalyst, and the temperature difference across the oxidation catalyst are key parameters for calculating actual conversion energy. Obtaining these parameters provides the necessary data for subsequent calculations of actual conversion energy, thereby accurately evaluating the oxidation catalyst's conversion efficiency.

[0062] The specific heat capacity of exhaust gas is related to its composition and temperature. This can be determined by looking up a pre-established table that correlates exhaust gas composition, temperature, and specific heat capacity based on real-time exhaust gas composition (measured by an exhaust gas analyzer) and temperature data (measured by a temperature sensor). Alternatively, an empirical formula can be used to calculate the specific heat capacity of exhaust gas by substituting the ratio of each component in the exhaust gas and its temperature into the formula.

[0063] This application can measure the intake air volume of the oxidation catalyst in real time using a flow sensor installed in the intake duct of the oxidation catalyst. The flow sensor can be of different types, such as thermal type and vortex type. The appropriate sensor should be selected based on actual needs, and its measurement accuracy and stability should be ensured.

[0064] The present application can measure the inlet and outlet temperatures of the oxidation catalyst in real time using temperature sensors installed at the inlet and outlet of the oxidation catalyst. The inlet temperature is subtracted from the outlet temperature to obtain the front-to-back temperature difference of the oxidation catalyst. To reduce measurement errors, the temperature sensors can be regularly calibrated, and the average value of multiple measurements can be used.

[0065] Step S105: Calculating actual conversion energy based on the exhaust gas specific heat capacity of the engine, the air intake amount of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst.

[0066] According to thermodynamic principles, the actual conversion energy can be calculated using the following formula: Actual Conversion Energy = Exhaust Gas Specific Heat × Intake Air Volume × Front-to-Front Temperature Difference. Substituting the exhaust gas specific heat, intake air volume, and front-to-back temperature difference obtained in step S104 into the above formula, the actual conversion energy of the oxidation catalyst is calculated.

[0067] Step S106: obtaining theoretical conversion energy based on the injection amount of the hydrogen.

[0068] Theoretical conversion energy is the maximum energy released by the complete oxidation of hydrogen under ideal conditions. Obtaining this theoretical conversion energy provides a benchmark for comparison with actual conversion energy, thereby assessing the gap between the actual conversion efficiency of an oxidation catalyst and ideal conditions.

[0069] This application pre-installs a flow sensor in the hydrogen injection system to measure the hydrogen injection volume in real time. The flow sensor must be able to accurately measure the hydrogen flow rate. The theoretical conversion energy is then calculated based on the calorific value of hydrogen (a known physical constant, typically 143 MJ / kg) and the injection volume. Theoretical conversion energy = Hydrogen injection volume × Hydrogen calorific value. Substituting the obtained hydrogen injection volume into the above formula will calculate the theoretical conversion energy.

[0070] Step S107: taking the ratio of the actual conversion energy to the theoretical conversion energy as the conversion efficiency of the oxidation catalyst.

[0071] The conversion efficiency of the oxidation catalyst is calculated by calculating the ratio of actual conversion energy to theoretical conversion energy, which intuitively reflects the energy conversion effect of the oxidation catalyst during actual operation. Conversion efficiency is an important indicator for measuring the performance of the oxidation catalyst and is of great significance for optimizing the design and operation of hydrogen internal combustion engines. In this step, the conversion efficiency of the oxidation catalyst is obtained by dividing the actual conversion energy calculated in step S105 by the theoretical conversion energy calculated in step S106. Conversion efficiency = actual conversion energy / theoretical conversion energy × 100%.

[0072] After calculating the conversion efficiency, analyze it to determine if it's within a reasonable range. If the conversion efficiency is too low, you may need to check the performance of the oxidation catalyst, the engine's operating parameters, or the accuracy of the measurement system. Also, record the conversion efficiency results for subsequent data analysis and performance evaluation.

[0073] The technical solution disclosed in the above-mentioned embodiments of the present application is aimed at measuring the DOC conversion efficiency of a hydrogen internal combustion engine. When it is determined that the oxidation catalyst is in an enabled condition, it is determined whether the hydrogen concentration in the oxidation catalyst is within a preset range. If it is within the preset range, the actual conversion energy is calculated based on the specific heat capacity of the engine's exhaust gas, the intake volume of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst. The ratio of the actual conversion energy to the theoretical conversion energy is used as the conversion efficiency of the oxidation catalyst. This solution uses the enabling condition and the hydrogen concentration as limiting conditions in the DOC conversion efficiency measurement process based on the characteristics of the hydrogen internal combustion engine, thereby improving the reliability of the measurement results of the DOC conversion efficiency of the hydrogen internal combustion engine.

[0074] After obtaining the hydrogen concentration, the hydrogen concentration may not be within a preset range. When the hydrogen concentration is not within the preset range, the hydrogen concentration in the oxidation catalyst can be adjusted by adjusting target parameters until the hydrogen concentration in the oxidation catalyst is within the preset range, wherein the target parameters include any one or more of an excess air coefficient, a post-injection amount, an ignition advance angle, an EGR flow rate, and a hydrogen injection timing.

[0075] The excess air coefficient (λ) is the ratio of the actual air supply to the theoretical air requirement. When λ is less than 1, the mixture is rich, with relatively more fuel; when λ is greater than 1, the mixture is lean, with relatively more air. In engines that use hydrogen for combustion, adjusting the excess air coefficient changes the ratio of air to hydrogen entering the cylinder. Reducing the air supply (decreasing λ) results in a relative excess of hydrogen, potentially increasing the amount of unreacted hydrogen after combustion and raising the hydrogen concentration in the oxidation catalyst. Conversely, increasing the air supply (increasing λ) results in a relative deficiency of hydrogen, leading to more complete combustion and potentially lowering the hydrogen concentration in the oxidation catalyst.

[0076] Post-injection injection quantity. Post-injection is the injection of additional fuel into the cylinder during the expansion or exhaust stroke, following the main injection. This post-injected fuel continues to burn or partially oxidize in high-temperature environments. Increasing the post-injection quantity allows more fuel (hydrogen) to enter the cylinder to participate in the combustion or oxidation reaction. This post-injection of hydrogen directly increases the amount of hydrogen in the cylinder, leading to an increase in the hydrogen concentration within the oxidation catalyst.

[0077] Ignition advance angle refers to the crankshaft angle from the moment of ignition to the moment the piston reaches top dead center. A suitable ignition advance angle ensures complete combustion of the fuel within the cylinder, improving the engine's thermal efficiency. Adjusting the ignition advance angle alters the start and course of combustion. If the ignition advance angle is too large, combustion begins prematurely, potentially leading to incomplete combustion and the production of more unburned hydrocarbons and hydrogen. If the ignition advance angle is too small, combustion is delayed, potentially reducing combustion temperature and pressure, affecting the hydrogen oxidation reaction and causing changes in the hydrogen concentration within the oxidation catalyst.

[0078] EGR (Exhaust Gas Recirculation) is a technology that reintroduces a portion of exhaust gas into the cylinder to participate in combustion. Exhaust gas contains a large amount of inert gases (such as nitrogen and carbon dioxide), which can lower combustion temperature and reduce the formation of nitrogen oxides. Increasing EGR flow increases the amount of exhaust gas entering the cylinder, diluting the fresh air and hydrogen mixture, lowering combustion temperature and speed. This results in incomplete hydrogen combustion and increases hydrogen concentration in the oxidation catalyst. Conversely, reducing EGR flow may increase combustion temperature and speed, allowing for more complete hydrogen combustion and reducing hydrogen concentration in the oxidation catalyst.

[0079] Hydrogen injection timing determines when hydrogen enters the cylinder, influencing the mixing and combustion processes. Adjusting the injection timing can adjust the distribution of hydrogen within the cylinder and the uniformity of its mixing with the air. If injection is too early, hydrogen has more time to mix with the air, potentially forming a more uniform mixture and promoting more complete combustion, potentially reducing the hydrogen concentration within the oxidation catalyst. If injection is too late, hydrogen may not have enough time to fully mix with the air, resulting in locally high hydrogen concentrations, incomplete combustion, and increased hydrogen concentration within the oxidation catalyst.

[0080] In this embodiment, enabling conditions are a prerequisite for accurately measuring the conversion efficiency of the oxidation catalyst: the oxidation catalyst has specific enabling conditions, such as operating temperature and gas flow rate. Only under these appropriate operating conditions can the oxidation catalyst effectively catalyze the oxidation of pollutants such as hydrogen. For example, the oxidation catalyst typically requires a certain temperature range (usually 200-600°C) to achieve high catalytic activity. If the temperature is too low, the catalytic reaction rate will be extremely slow, failing to effectively reduce the hydrogen concentration; if the temperature is too high, it may damage the catalyst or cause catalyst deactivation. Enabling conditions provide a stable environment for the catalytic reaction within the oxidation catalyst. In this environment, the contact opportunities between the reactants (such as hydrogen) and the catalyst surface and the reaction rate are relatively stable, facilitating accurate assessment and adjustment of the impact of target parameters on hydrogen concentration. If the oxidation catalyst is not in enabling conditions, the uncertainty of the catalytic reaction increases, and adjusting the target parameters may not achieve the desired effect on hydrogen concentration.

[0081] If the operating conditions of the oxidation catalyst change while the target parameters are being adjusted, it will be impossible to determine whether the change in hydrogen concentration is due to the adjustment of the target parameters or due to the change in operating conditions. For example, if the temperature of the oxidation catalyst suddenly drops during the adjustment of the excess air coefficient, the change in hydrogen concentration may be the result of a weakening of the catalytic reaction due to the temperature drop, rather than a direct effect of the excess air coefficient adjustment. Keeping the oxidation catalyst in an enabled operating condition can eliminate this interference and more accurately evaluate the impact of the target parameter adjustment on the hydrogen concentration. Therefore, in this solution, it is necessary to adjust the target parameters on the basis of keeping the oxidation catalyst in the enabled operating condition.

[0082] In this embodiment, the conversion efficiency of the DOC can be adjusted by means of target parameters. The number of target parameters can be multiple. In this embodiment, considering the different degrees of influence of different target parameters on hydrogen concentration, the present application can sort the target parameters based on the degree of influence of different target parameters on hydrogen concentration, and write these target parameters into a target parameter group based on the sorting results. When adjusting the hydrogen concentration, the target parameters in the target parameter group are selected as the adjustment targets based on the order of priority from high to low, and the hydrogen concentration in the oxidation catalyst is adjusted. During the adjustment process, it is determined that the oxidation catalyst has left the enabling condition. If the oxidation catalyst has left the enabling condition during the adjustment process, the adjustment target is returned to the previous adjustment step and the target parameter with the next priority is selected as the adjustment target. This is because the enabling condition is the basis for the normal operation of the oxidation catalyst. Leaving the enabling condition may cause abnormal catalytic reaction and affect the final calculation effect. By returning the adjustment step and changing the adjustment parameter, the system state can be readjusted to restore it to the enabling condition as much as possible before subsequent adjustment.

[0083] The conversion efficiency of an oxidation catalyst is a key indicator of its performance. After calculating the conversion efficiency, comparing it with the preset value can directly determine whether the current working status of the oxidation catalyst meets the standard. When the conversion efficiency is less than the preset value (such as 0.5), it indicates that there may be an abnormality in the oxidation catalyst. This abnormality may be caused by a variety of factors, among which hydrogen leakage is a more serious and likely situation. When hydrogen fails to fully react in the oxidation catalyst, resulting in a decrease in conversion efficiency, it may mean that there is an abnormal leakage path for hydrogen, so that some hydrogen does not participate in the normal catalytic oxidation reaction. Therefore, when the conversion efficiency is less than the preset value, it is necessary to trigger the hydrogen leak diagnosis strategy. When diagnosing hydrogen leakage, it is possible to diagnose both original engine hydrogen leakage and tail exhaust hydrogen leakage. The diagnostic methods include but are not limited to hydrogen leakage diagnosis using nitrogen oxides sensors, oxygen sensors, DOC efficiency and temperature rise before and after DOC.

[0084] This embodiment discloses a device for measuring DOC conversion efficiency of a hydrogen internal combustion engine. For the specific working contents of each unit in the device, please refer to the contents of the above method embodiment.

[0085] The following describes a device for measuring DOC conversion efficiency of a hydrogen internal combustion engine provided by an embodiment of the present invention. The device for measuring DOC conversion efficiency of a hydrogen internal combustion engine described below and the method for measuring DOC conversion efficiency of a hydrogen internal combustion engine described above can be referred to in correspondence with each other.

[0086] See also Figure 2 The present application discloses a device for measuring the DOC conversion efficiency of a hydrogen internal combustion engine. The device may include:

[0087] The operating condition judgment unit 10 is used to judge whether the oxidation catalyst is in an enabled operating condition;

[0088] A hydrogen concentration collection unit 20 is used to obtain the hydrogen concentration in the oxidation catalyst when the oxidation catalyst is in an enabled state;

[0089] A concentration determination unit 30 is configured to determine whether the hydrogen concentration is within a preset range;

[0090] a parameter acquisition unit 40 for acquiring the exhaust gas specific heat capacity of the engine, the intake air volume of the oxidation catalyst, and the temperature difference between the front and rear of the oxidation catalyst when the hydrogen concentration is within a preset range;

[0091] an actual conversion energy calculation unit 50 for calculating actual conversion energy based on the exhaust gas specific heat capacity of the engine, the intake air volume of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst;

[0092] a theoretical conversion energy acquisition unit 60, configured to acquire theoretical conversion energy based on the injection amount of the hydrogen;

[0093] The conversion efficiency calculation unit 70 is configured to use the ratio of the actual conversion energy to the theoretical conversion energy as the conversion efficiency of the oxidation catalyst.

[0094] Correspondingly, the present application also provides an electronic device, which includes at least one processing device and a storage device connected to the processing device, wherein: the storage device is used to store a computer program; the processing device is used to execute the computer program so that the electronic device can implement the hydrogen internal combustion engine DOC conversion efficiency measurement method as described in any one of the above.

[0095] The corresponding application also discloses a car, which may include the above-mentioned electronic equipment. The electronic equipment in this article may be an ECU (Electronic Control Unit), a VCU (Vehicle Control Unit), an MCU (Micro Controller Unit), an HCU (Hybrid Control Unit), etc.

[0096] See also Figure 3 As shown, the vehicle disclosed in this application uses a hydrogen internal combustion engine as its power source. A nitrogen oxide sensor and a temperature sensor are installed upstream of the DOC. Temperature sensors are also installed downstream of the DOC and downstream of the SCR. A nitrogen oxide sensor is also installed downstream of the SCR. Each sensor collects relevant parameters of the post-treatment system and transmits the collected results to the electronic device for data analysis.

[0097] For the convenience of description, the above system is described as being divided into various modules according to their functions. Of course, when implementing the present invention, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0098] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0099] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0100] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0101] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0102] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for measuring DOC conversion efficiency of a hydrogen internal combustion engine, characterized in that: include: Determining whether the oxidation catalyst is in an enabled operating condition; When the oxidation catalyst is in an enabled state, obtaining a hydrogen concentration in the oxidation catalyst; Determining whether the hydrogen concentration is within a preset range; When the hydrogen concentration is within a preset range, obtaining the exhaust gas specific heat capacity of the engine, the intake air volume of the oxidation catalyst, and the temperature difference between the front and rear of the oxidation catalyst; Calculating actual conversion energy based on the exhaust gas specific heat capacity of the engine, the air intake amount of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst; obtaining theoretical conversion energy based on the injection amount of the hydrogen; The ratio of the actual conversion energy to the theoretical conversion energy is taken as the conversion efficiency of the oxidation catalyst.

2. The method for measuring DOC conversion efficiency of a hydrogen internal combustion engine according to claim 1, characterized in that: The actual conversion energy is calculated based on the exhaust gas specific heat capacity of the engine, the intake air volume of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst, including: The product of the exhaust gas specific heat capacity of the engine, the air intake amount of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst is taken as the actual conversion energy.

3. The method for measuring DOC conversion efficiency of a hydrogen internal combustion engine according to claim 1, characterized in that: Determine whether the oxidation catalyst is in the enabled state, including: determining whether an intake air volume of the oxidation catalyst is greater than a preset intake air volume, whether the oxidation catalyst is in a stable operating state, and whether a temperature before the oxidation catalyst is greater than a preset temperature; When the intake air amount of the oxidation catalyst is greater than a preset intake air amount, the oxidation catalyst is in a stable operating condition, and the temperature before the oxidation catalyst is greater than a preset temperature, it is determined that the oxidation catalyst is in an enabled operating condition.

4. The method for measuring DOC conversion efficiency of a hydrogen internal combustion engine according to claim 1, characterized in that: When it is determined that the hydrogen concentration is not within a preset range, the method further includes: adjusting the hydrogen concentration in the oxidation catalyst by adjusting the target parameter until the hydrogen concentration in the oxidation catalyst is within a preset range; The target parameters include any one or more of excess air ratio, post-injection injection amount, ignition advance angle, EGR flow rate and hydrogen injection timing.

5. The method for measuring DOC conversion efficiency of a hydrogen internal combustion engine according to claim 4, characterized in that: Adjusting the hydrogen concentration in the oxidation catalyst by adjusting the target parameter includes: The target parameter is adjusted on the basis of maintaining the oxidation catalyst in the enabled operating condition to adjust the hydrogen concentration in the oxidation catalyst to within a preset range.

6. The method for measuring DOC conversion efficiency of a hydrogen internal combustion engine according to claim 5, characterized in that: Adjusting the target parameter on the basis of maintaining the oxidation catalyst in the enabling operating condition includes: A target parameter in the target parameter group is selected as an adjustment object based on a descending priority order, the hydrogen concentration in the oxidation catalyst is adjusted, and it is determined that the oxidation catalyst is out of an enabling operating condition during the adjustment process. When the oxidation catalyst is out of the enabling operating condition, the adjustment object is returned to the previous adjustment step, and a target parameter with the next highest priority in the target parameter group is selected as the adjustment object. The hydrogen concentration in the oxidation catalyst is continuously adjusted until the hydrogen concentration in the oxidation catalyst is adjusted to within a preset range.

7. The method for measuring DOC conversion efficiency of a hydrogen internal combustion engine according to claim 1, characterized in that: After taking the ratio of the actual conversion energy to the theoretical conversion energy as the conversion efficiency of the oxidation catalyst, the method further includes: Determining whether the conversion efficiency is less than a preset conversion efficiency; When the conversion efficiency is less than the preset conversion efficiency, a hydrogen leakage diagnosis strategy is executed.

8. A device for measuring DOC conversion efficiency of a hydrogen internal combustion engine, characterized in that: include: An operating condition judgment unit, used to judge whether the oxidation catalyst is in an enabled operating condition; a hydrogen concentration acquisition unit, configured to acquire the hydrogen concentration in the oxidation catalyst when the oxidation catalyst is in an enabled operating condition; a concentration judging unit, configured to judge whether the hydrogen concentration is within a preset range; a parameter acquisition unit, configured to acquire the exhaust gas specific heat capacity of the engine, the intake air volume of the oxidation catalyst, and the temperature difference between the front and rear of the oxidation catalyst when the hydrogen concentration is within a preset range; an actual conversion energy calculation unit, configured to calculate the actual conversion energy based on the exhaust gas specific heat capacity of the engine, the intake air volume of the oxidation catalyst, and the temperature difference before and after the oxidation catalyst; a theoretical conversion energy acquisition unit, configured to acquire theoretical conversion energy based on the injection amount of the hydrogen; The conversion efficiency calculation unit is configured to use the ratio of the actual conversion energy to the theoretical conversion energy as the conversion efficiency of the oxidation catalyst.

9. An electronic device, characterized in that: include: at least one processing device and a storage device connected to the processing device, wherein: The storage device is used to store computer programs; The processing device is configured to execute the computer program so as to enable the electronic device to implement the method for measuring the DOC conversion efficiency of a hydrogen internal combustion engine according to any one of claims 1 to 7.

10. An automobile, characterized in that: The electronic device comprising claim 9.

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