Engine control device and humidity measuring method

Abstract

The invention relates to the technical field of vehicles, and provides an engine control device and a humidity measuring method. The method comprises the following steps: detecting the actual pump current of the wide-range front oxygen sensor in the current state; obtaining the theoretical pump current of the wide-area front oxygen sensor; comparing a current difference value Dip between the actual pump current and the theoretical pump current with a set threshold value, and if the current difference value is greater than the set threshold value, entering the next step; when the engine is in the humidity detection working condition, a natural gas injection quantity coefficient and a knock intensity indication coefficient are collected and are subtracted from corresponding preset standard values, and a knock difference value and a natural gas injection quantity difference value are obtained; calculating the relative humidity of the intake air of the engine; and by searching a preset conversion table of the relative humidity and the absolute humidity, obtaining the target humidity of the intake air of the engine. The technical problems that an intake oxygen sensor and an air mass flow sensor need to be additionally installed in traditional engine humidity measurement, the structure is complex, cost is high, and reliability is insufficient are solved.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to an engine control device and a humidity measurement method. Background Technology

[0002] Driven by both the China VI emission standards for natural gas and the fuel economy of natural gas, major domestic OEMs have launched natural gas engines with different technological approaches to meet China VI emission standards, and corresponding China VI natural gas vehicles have been widely launched and sold. Currently, the mainstream China VI natural gas engine technology in China is stoichiometric combustion + cooled high-pressure EGR + single-point injection in the intake manifold. In actual vehicle use, users have gradually discovered that compared with the direct injection lean combustion mode of diesel engines, the power output of single-point injection stoichiometric combustion in the intake manifold is greatly affected by environmental changes, especially under high intake air humidity conditions, where power loss is particularly noticeable. Analysis of extensive bench test data reveals two mechanisms by which high humidity affects power: First, as intake air humidity increases, the oxygen content in the intake air decreases. Under equivalence mode where air volume is the control target, this leads to a reduction in the total amount of oxygen entering the engine, resulting in a decrease in natural gas injection. Second, as intake air humidity increases, the water vapor content in the intake air increases, which indirectly increases the engine's EGR rate, slows down the combustion speed of natural gas in the cylinder, and reduces knocking. However, with the corresponding ignition angle remaining unchanged, it reduces the combustion heat release efficiency, affecting gas consumption and engine crankshaft torque output.

[0003] To detect ambient humidity, current methods typically employ temperature and humidity sensors directly. Simultaneously, engine intake air volume and combustion parameters are corrected based on the detected humidity. However, these types of automotive temperature and humidity sensors are relatively expensive, and their 0%~100% relative humidity measurement range is overly redundant for current applications. Bench test data indicates that a significant impact on the power output of currently configured natural gas engines only occurs when the intake air relative humidity exceeds 85%. Within the 0%~80% intake air relative humidity range, engine power output remains essentially unchanged, requiring no correction of combustion parameters, including intake air volume, ignition angle, and EGR rate. Summary of the Invention

[0004] The purpose of this invention is to provide an engine control device and a humidity measurement method, solving the technical problems of traditional engine humidity measurement which requires the additional installation of an intake oxygen sensor and an air mass flow sensor, resulting in complex structure, high cost, and insufficient reliability. The specific solution is as follows:

[0005] An engine control device, comprising:

[0006] The intake unit is used to supply air to the engine for combustion.

[0007] The exhaust control unit is used to deliver a portion of the exhaust gas to the engine for combustion.

[0008] Fuel delivery unit, used to deliver fuel to the engine;

[0009] The common terminal of the intake unit, exhaust control unit, and fuel delivery unit is connected to the mixer; the gas delivered by the intake unit, exhaust control unit, and fuel delivery unit is mixed by the mixer and then input into the engine for combustion.

[0010] It also includes: a sensor assembly, wherein the sensor assembly is used to collect engine operating parameters; the operating parameters include at least: pump current, natural gas injection quantity coefficient, knock intensity indication coefficient, atmospheric pressure and ambient temperature in the wide-range oxygen front sensor;

[0011] It also includes: an ECU that is electrically connected to the sensor assembly;

[0012] The ECU calculates the target humidity of the engine intake air based on operating parameters and using a preset control method.

[0013] Optionally, the intake unit includes:

[0014] A turbocharger and an intercooler are connected sequentially by pipelines; the turbocharger includes a compressor and a turbine; the compressor is used to deliver intake air, and the turbine is used to deliver exhaust air.

[0015] The output end of the intercooler is connected to the mixer, and an electronic throttle valve is arranged on the pipe between the two.

[0016] The air is pressurized by the compressor of the turbocharger and then sent to the intercooler for cooling. The air is then sent to the mixer for mixing and the mixed air is sent to the combustion chamber of the engine through the intake manifold for combustion. An intake air temperature sensor is installed on the pipe between the intake manifold and the mixer.

[0017] Optionally, the exhaust gas control unit includes:

[0018] The EGR cooler and EGR flow control unit are connected in sequence; the input of the EGR flow control unit is connected to the exhaust manifold of the engine; the output of the EGR flow control unit is connected to the mixer to regulate the amount of exhaust gas entering the mixer.

[0019] Optionally, the fuel delivery unit includes:

[0020] A natural gas intake injection assembly and a natural gas pressure regulator are connected in sequence; the natural gas intake injection assembly is used to input natural gas into the mixer.

[0021] Optionally, the sensor assembly includes at least:

[0022] Wide-range oxygen sensor, atmospheric pressure sensor, ambient temperature sensor, knock sensor, and natural gas flow sensor;

[0023] The wide-range front oxygen sensor is arranged on the downstream pipe of the turbocharger turbine and is used to detect the oxygen content in the engine exhaust gas based on the change in the internal pump current.

[0024] The atmospheric pressure sensor is located inside the ECU;

[0025] The knock sensor is located on one side of the engine block and is used to detect the knock intensity indicator coefficient of the engine.

[0026] The natural gas flow sensor is located inside the natural gas intake injection assembly and is used to collect the natural gas injection quantity coefficient.

[0027] Optionally, when the engine is in operation, the ECU shuts down the fuel delivery unit and the exhaust control unit to stop delivering fuel and exhaust gas, and delivers air sequentially through the intake unit through the engine and exhaust manifold to the downstream pipe of the turbine. The oxygen content of the air is measured by the pump current of the wide-range front oxygen sensor on the downstream pipe. The operating conditions include: reverse towing and long downhill driving.

[0028] The pump current based on the wide-range front oxygen sensor is controlled by a preset method to calculate the target humidity of the engine intake air.

[0029] A method for measuring the humidity of an engine, applied to the aforementioned device; the method includes the following steps:

[0030] S1: When the vehicle is in operation, the actual pump current IP of the wide-area front oxygen sensor is detected in real time; the operation conditions include at least: reverse towing operation and long downhill operation.

[0031] S2: Obtain the vehicle's current altitude based on atmospheric pressure, and based on the altitude, obtain the theoretical pump current of the wide-range front oxygen sensor by looking up a preset reference table;

[0032] S3: The difference D between the actual pump current IP and the theoretical pump current. ip Compared with a set threshold, if the current difference D ip If the value exceeds the set threshold, proceed to the next step;

[0033] S4: When the engine is in humidity detection mode, the natural gas injection quantity coefficient and knock intensity indication coefficient are collected, and the difference between them and the corresponding preset standard values ​​is calculated to obtain the knock difference and natural gas injection quantity difference; the humidity detection mode includes at least: medium and high load mode;

[0034] S5: Based on the obtained current difference, knock difference, and natural gas injection quantity difference, the relative humidity of the engine intake air is calculated using a weighted calculation formula;

[0035] S6: Based on the acquired relative humidity, current ambient temperature, and atmospheric pressure, the target humidity of the engine intake air is obtained by looking up the preset conversion table between relative humidity and absolute humidity.

[0036] An electronic device includes: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus; characterized in that the memory stores a computer program, which, when executed by the processor, causes the processor to perform the steps of the method.

[0037] A computer-readable storage medium storing a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the steps of the method described herein.

[0038] A simulation platform, comprising:

[0039] An electronic device for implementing the steps of the method;

[0040] A processor that runs a program, and when the program runs, it executes the steps of the method from data output by the electronic device.

[0041] A storage medium for storing a program that, when run, executes the steps of the method on data output from an electronic device.

[0042] The above solution achieves the following beneficial technical effects:

[0043] This application provides an engine control device and a humidity measurement method. First, based on the direct correlation between the pump current of the wide-range front oxygen sensor and humidity, and the indirect coupling relationship between the natural gas injection quantity coefficient and the knock intensity indication coefficient and humidity, a virtual humidity detection model is constructed through a multi-parameter weighted algorithm. This avoids the environmental influence of high temperature and exhaust gas corrosion that physical sensors are susceptible to, and achieves the fusion of cross-dimensional data on combustion state, oxygen concentration, and humidity, making the detection accuracy more consistent with the actual operating conditions of the engine. Moreover, the humidity detection is linked to the hardware structure of the intake, exhaust gas control, and fuel delivery units. Without large-scale changes to the structural layout, it can be implemented simply by upgrading the ECU algorithm. This not only reduces the cost of modification and mass production, but also enables the reverse dynamic optimization of the air-to-air ratio of the mixer, EGR flow, and ignition timing through real-time calculation of the target humidity. This solves the technical defects of traditional engines such as decreased combustion efficiency and delayed knock control in high humidity environments, and improves the overall power response and emission capabilities of the engine in complex humidity environments. Attached Figure Description

[0044] Figure 1 A flowchart illustrating the method for measuring humidity in an engine;

[0045] Figure 2 This is a connection diagram of the engine control unit;

[0046] Figure 3 A graph showing the output characteristics of the pump current of the wide-range front oxygen sensor under different intake air humidity conditions during engine reversing operation;

[0047] Figure 4 Humidity detection activation logic block diagram;

[0048] Figure 5 This is a flowchart illustrating an engine humidity measurement method according to one embodiment. Detailed Implementation

[0049] To make the purpose, technical solution, and advantages of this application clearer, the following will be described in conjunction with the appendix. Figure 1 -to Figure 5 This application will be described in further detail. It is obvious that the described embodiments are merely some, not all, of the embodiments described herein. All other embodiments obtained by those skilled in the art based on the embodiments described herein without inventive effort are within the scope of protection of this application.

[0050] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to limit the application. The singular forms “a,” “said,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0051] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0052] It should be understood that although the terms first, second, third, etc., may be used in the embodiments of this application, these descriptions should not be limited to these terms. These terms are only used to distinguish the descriptions. For example, first may also be referred to as second without departing from the scope of the embodiments of this application, and similarly, second may also be referred to as first.

[0053] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”

[0054] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0055] It should be noted that any symbols and / or numbers present in the specification that are not marked in the accompanying drawings are not reference numerals.

[0056] The optional embodiments of this application are described in detail below with reference to the accompanying drawings.

[0057] In the diagram: Engine block 10, knock sensor 11, EGR cooler 12, atmospheric pressure sensor 13, ambient temperature sensor 14, engine electronic control unit (ECU) 15, natural gas intake injection assembly 16, EGR flow control unit 17, mixer 18, intake air temperature and pressure sensor 19, electronic throttle 20, intercooler 21, turbocharger 22, wide-range front oxygen sensor 23, catalytic converter 24, natural gas pressure regulator 161, intake manifold 111, exhaust manifold 112;

[0058] Figure 2 An engine control device shown includes:

[0059] The intake unit is used to supply air to the engine for combustion.

[0060] The exhaust control unit is used to deliver a portion of the exhaust gas to the engine for combustion.

[0061] Fuel delivery unit, used to deliver fuel to the engine;

[0062] The common terminal of the intake unit, exhaust control unit, and fuel delivery unit is connected to the mixer; the gas delivered by the intake unit, exhaust control unit, and fuel delivery unit is mixed by the mixer and then input into the engine for combustion.

[0063] It also includes: a sensor assembly, wherein the sensor assembly is used to collect engine operating parameters; the operating parameters include at least: pump current, natural gas injection quantity coefficient, knock intensity indication coefficient, atmospheric pressure and ambient temperature in the wide-range oxygen front sensor;

[0064] It also includes: an ECU that is electrically connected to the sensor assembly;

[0065] The ECU calculates the target humidity of the engine intake air based on operating parameters and using a preset control method.

[0066] Specifically, this application, based on the direct correlation between the wide-domain front oxygen sensor pump current and humidity, and the indirect coupling relationship between the natural gas injection quantity coefficient and the knock intensity indication coefficient and humidity, constructs a virtual humidity detection model through a multi-parameter weighted algorithm. This avoids the environmental impact of physical sensors being susceptible to high temperatures and exhaust gas corrosion, and achieves the fusion of cross-dimensional data on combustion state, oxygen concentration, and humidity, making the detection accuracy more consistent with the actual operating conditions of the engine. Moreover, by linking humidity detection with the hardware structure of the intake, exhaust, and fuel delivery units, no large-scale structural layout modifications are required. It can be implemented simply by upgrading the ECU algorithm, which not only reduces the cost of modification and mass production, but also enables the reverse dynamic optimization of the air-to-air ratio of the mixer, EGR flow, and ignition timing through real-time calculation of the target humidity. This solves the technical defects of traditional engines such as decreased combustion efficiency and delayed knock control in high humidity environments, and improves the overall power response and emission capabilities of the engine in complex humidity environments.

[0067] Furthermore, the intake unit includes:

[0068] A turbocharger and an intercooler are connected sequentially by pipelines; the turbocharger includes a compressor and a turbine; the compressor is used to deliver intake air, and the turbine is used to deliver exhaust air.

[0069] The output end of the intercooler is connected to the mixer, and an electronic throttle valve is arranged on the pipe between the two.

[0070] The air is pressurized by the compressor of the turbocharger and then sent to the intercooler for cooling. The air is then sent to the mixer for mixing and the mixed air is sent to the combustion chamber of the engine through the intake manifold for combustion. An intake air temperature sensor is installed on the pipe between the intake manifold and the mixer.

[0071] Specifically, in this embodiment, the sequential connection between the turbocharger compressor and the intercooler enables rapid cooling after intake air pressurization, improving intake air density to ensure combustion power while preventing high-temperature intake air from affecting combustion stability. Furthermore, an electronic throttle is installed between the intercooler and the mixer, dynamically adjusting the intake airflow based on virtual humidity detection results and engine operating conditions. Simultaneously, an intake air temperature sensor is placed between the mixer and the intake manifold to acquire real-time mixed intake air temperature parameters. This data, complementing that of a wide-range oxygen sensor, provides multi-dimensional data support for the ECU to optimize the air-fuel ratio and EGR flow, achieving dynamic adaptation of intake airflow, temperature, and mixing ratio. This significantly improves the intake accuracy of the engine under different humidity and load conditions.

[0072] Furthermore, the exhaust gas control unit includes:

[0073] The EGR cooler and EGR flow control unit are connected in sequence; the input of the EGR flow control unit is connected to the exhaust manifold of the engine; the output of the EGR flow control unit is connected to the mixer to regulate the amount of exhaust gas entering the mixer.

[0074] The fuel delivery unit includes:

[0075] A natural gas intake injection assembly and a natural gas pressure regulator are connected in sequence; the natural gas intake injection assembly is used to input natural gas into the mixer.

[0076] Furthermore, the sensor assembly includes at least:

[0077] Wide-range oxygen sensor, atmospheric pressure sensor, ambient temperature sensor, knock sensor, and natural gas flow sensor;

[0078] The wide-range front oxygen sensor is arranged on the downstream pipe of the turbocharger turbine and is used to detect the oxygen content in the engine exhaust gas based on the change in the internal pump current.

[0079] The atmospheric pressure sensor is located inside the ECU;

[0080] The knock sensor is located on one side of the engine block and is used to detect the knock intensity indicator coefficient of the engine.

[0081] The natural gas flow sensor is located inside the natural gas intake injection assembly and is used to collect the natural gas injection quantity coefficient.

[0082] It should be noted that the ambient temperature sensor in this embodiment is usually installed in the middle of the vehicle crossbeam or other locations far from the engine compartment to detect the ambient atmospheric temperature of the vehicle and engine.

[0083] Atmospheric pressure sensors are typically integrated into the engine control unit (ECU) to detect the atmospheric pressure of the vehicle and engine operating environment, and are used for altitude conversion.

[0084] Natural gas intake injector assemblies are typically installed on the intake side of the engine block for natural gas supply and metering. They are usually available in two types: nozzle type and continuous flow type, and have an integrated natural gas flow sensor for collecting the natural gas injection quantity coefficient.

[0085] The mixer is installed downstream of the electronic throttle valve; the mixer outlet is connected to the intake manifold, and the EGR flow control unit is directly fixed to the mixer. The mixer is mainly used to ensure that fresh air, natural gas and exhaust gas delivered by EGR are fully mixed.

[0086] The knock sensor is installed on the surface of the engine block, away from the engine water passages, to detect the intensity of engine combustion, thereby protecting the engine for safe operation.

[0087] The wide-range front oxygen sensor signal is installed between the downstream of the turbocharger turbine and the upstream of the catalytic converter. It is used to detect the oxygen content in the engine exhaust gas to ensure that the engine is in equivalence combustion and to control emissions.

[0088] The EGR flow control unit includes an EGR valve, an EGR pressure and temperature sensor, and connecting pipes, which are used for EGR flow control and metering, and are fixed to the mixer.

[0089] This embodiment also includes an intake air temperature and pressure sensor arranged between the mixer and the intake manifold, used to measure the temperature and pressure signals of the mixed gas and thereby obtain the engine operating conditions and status.

[0090] The engine control unit (ECU) is electrically connected to the natural gas intake injector assembly, electronic throttle, EGR flow control unit, intake air temperature and pressure sensor, wide-range pre-oxygen sensor, and knock sensor. It is used to receive sensor input signals and output actuator drive information to ensure the safe and stable operation of the natural gas engine.

[0091] In one specific embodiment, when the engine is in operation, the ECU shuts down the fuel delivery unit and the exhaust control unit to stop delivering fuel and exhaust gas, and delivers air sequentially through the intake unit through the engine and exhaust manifold to the downstream pipe of the turbine. The oxygen content of the air is measured by the pump current of the wide-range front oxygen sensor on the downstream pipe. The operating conditions include: reverse towing condition and long downhill condition.

[0092] The pump current based on the wide-range front oxygen sensor is controlled by a preset method to calculate the target humidity of the engine intake air.

[0093] Specifically, in this embodiment, the ECU actively shuts down the fuel delivery unit and the exhaust control unit, while retaining only the intake unit to deliver pure air. This fundamentally eliminates the interference of fuel combustion products and exhaust gas on oxygen content detection, allowing the wide-range front oxygen sensor to accurately capture the pump current signal corresponding to pure intake air. The target humidity is then calculated using a preset control method. Thus, without the need for an additional physical humidity sensor, the design concept of operating condition isolation and pure air detection overcomes the technical bottleneck of traditional humidity detection being easily affected by combustion interference. Furthermore, the hardware structure achieves functional upgrades, ensuring detection accuracy, cost control, and operating condition matching, greatly improving the reliability and practicality of humidity sensing in complex environments.

[0094] It is understandable that when the engine is in reverse towing mode or the vehicle is descending a long slope, natural gas injection has stopped, the EGR valve is closed, and fresh air enters the combustion chamber through the intake valve. It then flows through the exhaust valve, through the exhaust manifold, and to the turbine side of the turbocharger. After several cycles, the wide-range front oxygen sensor installed downstream of the turbine detects the fresh air, and the ECU detects the pump current of the wide-range front oxygen sensor. The pump current of the wide-range front oxygen sensor corresponding to high humidity (greater than 85% relative humidity) fresh air has a certain degree of differentiation from the pump current corresponding to fresh air under standard conditions. Due to the decrease in oxygen content, the pump current will decrease accordingly. In this embodiment, the pump current of fresh air under standard conditions is the theoretical pump current of the wide-range front oxygen sensor obtained by pre-calibration at 25°C, 1023 hPa, and 50% relative humidity.

[0095] By calculating the difference between the actual pump current and the theoretical pump current of the wide-range front oxygen sensor under vehicle operating conditions, and using a preset control method (i.e., the engine humidity measurement method described below), the target humidity of the engine intake air (i.e., the virtual humidity detection result) is calculated. This provides multi-dimensional data perception support for the subsequent ECU optimization of air-to-air ratio and EGR flow, thereby achieving dynamic adaptation of intake flow, temperature and mixing ratio.

[0096] On the other hand, such as Figure 1 A method for measuring engine humidity, as shown, is applied to the aforementioned device; the method includes the following steps:

[0097] S1: When the vehicle is in operation, the actual pump current IP of the wide-area front oxygen sensor is detected in real time; the operation conditions include at least: reverse towing operation and long downhill operation.

[0098] S2: Obtain the vehicle's current altitude based on atmospheric pressure, and based on the altitude, obtain the theoretical pump current of the wide-range front oxygen sensor by looking up a preset reference table;

[0099] S3: The difference D between the actual pump current IP and the theoretical pump current. ip Compared with a set threshold, if the current difference D ip If the value exceeds the set threshold, proceed to the next step;

[0100] S4: When the engine is in humidity detection mode, the natural gas injection quantity coefficient and knock intensity indication coefficient are collected, and the difference between them and the corresponding preset standard values ​​is calculated to obtain the knock difference and natural gas injection quantity difference; the humidity detection mode includes at least: medium and high load mode;

[0101] S5: Based on the obtained current difference, knock difference, and natural gas injection quantity difference, the relative humidity of the engine intake air is calculated using a weighted calculation formula;

[0102] S6: Based on the acquired relative humidity, current ambient temperature, and atmospheric pressure, the target humidity of the engine intake air is obtained by looking up the preset conversion table between relative humidity and absolute humidity.

[0103] Specifically, in this embodiment, fuel and exhaust gas delivery are first shut off during reverse towing and long downhill conditions. A wide-range pre-oxygen sensor acquires the interference-free pure air pump current. Based on the theoretical pump current correlated with altitude, high humidity detection conditions are selected. Then, under medium-to-high load conditions, the difference between injection volume and knock coefficient is collected. A weighted algorithm is used to calculate relative humidity using the deviation data. Finally, the target humidity is obtained by looking up tables based on temperature and pressure parameters. The advantage of this design is that by isolating operating conditions and utilizing multiple parameters, it overcomes the accuracy limitations of existing single-sensor detection, thus achieving accurate humidity measurement without the need for expensive humidity sensors, saving production costs.

[0104] It is understood that when the engine humidity detection mode is operating in this application, the wide-range front oxygen sensor is in a single-voltage drive mode, and the humidity calculation process uses a weighted calculation method based on three dimensions: pump current deviation, fuel factor deviation, and knock intensity indication coefficient deviation, which falls under the category of virtual sensor modeling. This model is used to detect intake air relative humidity exceeding 85%. The solution provided by this patent does not require the installation of additional intake oxygen sensors and air mass flow sensors, offering a cost advantage; and being in a single-voltage drive mode, it has a simple structure and high reliability.

[0105] Example

[0106] See Figure 4 As shown

[0107] (1) When the natural gas engine is in reverse driving mode, read the wide-range front oxygen sensor pump current IP in real time under the current state.

[0108] (2) Calculate the actual altitude of the vehicle based on the measured atmospheric pressure under the current conditions. Figure 3 The graph shown illustrates the output characteristics of the pump current of the wide-range front oxygen sensor under different intake air humidity conditions during engine reversing operation. Refer to the graph for the corresponding altitude. Figure 3 The characteristic graph shows the measured pump current pre-calibrated by the wide-range pre-oxygen sensor at 50% relative humidity, and uses this as the reference pump current IP. ref Or the theoretical pump current.

[0109] (3) Calculate the pump current deviation D between (1) and (2). ip and with the set threshold D ref The parameters are compared. If the pump current deviation exceeds the set threshold, the humidity detection program can be initiated.

[0110] It should be noted that, compared to the fresh air pump current IP, the deviation D ip The numerical value is small; for reasons of accuracy, this deviation D is considered small. ip It cannot be directly used for humidity conversion.

[0111] It should be further explained that when the engine enters the humidity detection program, the engine reversing condition is no longer used as the test condition. Instead, medium and high loads are selected as specific humidity detection conditions. The main reasons are: medium and high loads are more representative of the common operating conditions of the whole vehicle, especially for medium and heavy-duty commercial vehicles; in addition, medium and high loads can more clearly reflect the impact of high humidity intake on engine power and combustion conditions, which is more conducive to humidity conversion and greatly helps the accuracy of the model.

[0112] See Figure 5 As shown

[0113] The humidity detection procedure is as follows:

[0114] (1) When the engine is operating in a specific humidity detection range (such as medium or high load), retrieve the engine's fuel factor (i.e., natural gas injection quantity coefficient) at this time, compare this factor with the reference factor, and take the difference D. fuel The baseline factor can be obtained through engine bench calibration, that is, the actual fuel injection factor under the same operating conditions with 50% intake air humidity. Generally speaking, the fuel injection factor decreases due to increased humidity.

[0115] (2) Similar to (1), retrieve the engine knock intensity indicator coefficient at this time, compare the coefficient with the reference coefficient, and take the difference D. knock The baseline coefficient was obtained under 50% intake air humidity conditions, representing the actual engine combustion knock intensity coefficient under the same operating conditions. Generally speaking, the knock intensity indicator coefficient decreases as humidity increases.

[0116] (3) Obtain the pump current deviation D obtained in the deviation and humidity detection mode according to (1) and (2). ip A weighted algorithm is used to establish the correspondence between the deviations of the three factors and the relative humidity (RH). The specific formula is as follows: RH = α * D ip +β*D fuel +γ*D knock α, β, γ: weights; α: influence factor based on oxygen sensor pump current deviation; β: influence factor based on fuel coefficient deviation; γ: influence factor based on knock intensity indicator coefficient deviation.

[0117] (4) Based on the calculated relative humidity, and combined with the obtained ambient temperature and atmospheric pressure, the absolute humidity AH can be obtained by consulting the relative humidity and absolute humidity conversion table.

[0118] (5) Considering the failure of sensor components and the randomness of the testing process, a rationality verification step is set up in the process to ensure the reliability of measurement and calculation results.

[0119] In summary, this application proposes a design method to deduce target humidity by utilizing the actual performance changes of a natural gas engine in a high-humidity intake environment and to quantify their relationship. Specific changes include: a decrease in pump current of the wide-range front oxygen sensor under engine reversing conditions, a reduction in the combustion factor of the natural gas injection unit, and a weakening of the engine's knock intensity indication coefficient under high humidity. Based on these characteristics, this invention establishes a corresponding model, introduces an algorithm, constructs the physical and mathematical relationship between humidity and pump current, combustion factor, and knock intensity indication coefficient, and extracts key influencing factors.

[0120] 2. This invention selects the change in pump current of a wide-range front oxygen sensor in a high-humidity intake environment under engine reversing conditions as a prerequisite for triggering humidity detection. The key point is the selection of the reference pump current, which needs to take into account altitude, reference humidity and ambient temperature to ensure that the change has sufficient distinguishability and prevent misjudgment and missed detection of humidity.

[0121] 3. This invention selects engine under medium and high load conditions, reads engine combustion factor and knock intensity indicator coefficient, and determines the variable factors in the humidity calculation formula through difference calculation. The key point is to obtain the reference combustion factor and reference knock intensity indicator coefficient, which needs to take into account the change of gas quality, reference humidity, intake air temperature and engine load.

[0122] 4. This invention creatively proposes a weighted method for relative humidity calculation and extracts weight values.

[0123] 5. This invention proposes to use a lookup table method, combining the relative humidity calculated in item 4 with the environmental pressure and temperature measured by the engine control system, to directly obtain the absolute humidity.

[0124] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. An engine control device, characterized in that, include: The intake unit is used to supply air to the engine for combustion. The exhaust control unit is used to deliver a portion of the exhaust gas to the engine for combustion. Fuel delivery unit, used to deliver fuel to the engine; The common terminal of the intake unit, exhaust control unit, and fuel delivery unit is connected to the mixer; the gas delivered by the intake unit, exhaust control unit, and fuel delivery unit is mixed by the mixer and then input into the engine for combustion. It also includes: a sensor assembly, wherein the sensor assembly is used to collect engine operating parameters; the operating parameters include at least: pump current, natural gas injection quantity coefficient, knock intensity indication coefficient, atmospheric pressure and ambient temperature in the wide-range oxygen front sensor; It also includes: an ECU that is electrically connected to the sensor assembly; The ECU calculates the target humidity of the engine intake air based on operating parameters and using a preset control method.

2. The engine control device according to claim 1, characterized in that, The intake unit includes: A turbocharger and an intercooler are connected sequentially by pipelines; the turbocharger includes a compressor and a turbine; the compressor is used to deliver intake air, and the turbine is used to deliver exhaust air. The output end of the intercooler is connected to the mixer, and an electronic throttle valve is arranged on the pipe between the two. The air is pressurized by the compressor of the turbocharger and then sent to the intercooler for cooling. The air is then sent to the mixer for mixing and the mixed air is sent to the combustion chamber of the engine through the intake manifold for combustion. An intake air temperature sensor is installed on the pipe between the intake manifold and the mixer.

3. The engine control device according to claim 2, characterized in that, The exhaust gas control unit includes: The EGR cooler and EGR flow control unit are connected in sequence; the input of the EGR flow control unit is connected to the exhaust manifold of the engine; the output of the EGR flow control unit is connected to the mixer to regulate the amount of exhaust gas entering the mixer.

4. The engine control device according to claim 3, characterized in that, The fuel delivery unit includes: A natural gas intake injection assembly and a natural gas pressure regulator are connected in sequence; the natural gas intake injection assembly is used to input natural gas into the mixer.

5. The engine control device according to claim 4, characterized in that, The sensor assembly includes at least: Wide-range oxygen sensor, atmospheric pressure sensor, ambient temperature sensor, knock sensor, and natural gas flow sensor; The wide-range front oxygen sensor is arranged on the downstream pipe of the turbocharger turbine and is used to detect the oxygen content in the engine exhaust gas based on the change in the internal pump current. The atmospheric pressure sensor is located inside the ECU; The knock sensor is located on one side of the engine block and is used to detect the knock intensity indicator coefficient of the engine. The natural gas flow sensor is located inside the natural gas intake injection assembly and is used to collect the natural gas injection quantity coefficient.

6. The engine control device according to claim 5, characterized in that, When the engine is in operation, the ECU shuts down the fuel delivery unit and the exhaust control unit to stop delivering fuel and exhaust gas. Air is then delivered sequentially through the intake unit, through the engine and exhaust manifold, to the downstream pipe of the turbine. The oxygen content of the air is measured by the pump current of the wide-range front oxygen sensor on the downstream pipe. The operating conditions include: reverse towing and long downhill driving. The pump current based on the wide-range front oxygen sensor is controlled by a preset method to calculate the target humidity of the engine intake air.

7. A method for measuring the humidity of an engine, characterized in that, Applied to the apparatus according to any one of claims 1-6; the method comprises the following steps: S1: When the vehicle is in operation, the actual pump current IP of the wide-area front oxygen sensor is detected in real time; the operation conditions include at least: reverse towing operation and long downhill operation. S2: Obtain the vehicle's current altitude based on atmospheric pressure, and based on the altitude, obtain the theoretical pump current of the wide-range front oxygen sensor by looking up a preset reference table; S3: The difference D between the actual pump current IP and the theoretical pump current. ip Compared with a set threshold, if the current difference D ip If the value exceeds the set threshold, proceed to the next step; S4: When the engine is in humidity detection mode, the natural gas injection quantity coefficient and knock intensity indication coefficient are collected, and the difference between them and the corresponding preset standard values ​​is calculated to obtain the knock difference and natural gas injection quantity difference; the humidity detection mode includes at least: medium and high load mode; S5: Based on the obtained current difference, knock difference, and natural gas injection quantity difference, the relative humidity of the engine intake air is calculated using a weighted calculation formula; S6: Based on the acquired relative humidity, current ambient temperature, and atmospheric pressure, the target humidity of the engine intake air is obtained by looking up the preset conversion table between relative humidity and absolute humidity.

8. An electronic device, comprising: The system comprises a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus; characterized in that the memory stores a computer program, which, when executed by the processor, causes the processor to perform the steps of the method described in claim 7.

9. A computer-readable storage medium, characterized in that, The device stores a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the steps of the method as described in claim 7.

10. A simulation platform, characterized in that, include: An electronic device for implementing the steps of the method of claim 7; A processor that runs a program, which, when running, executes the steps of the method of claim 7 from data output by the electronic device. A storage medium for storing a program that, when run, performs the steps of the method of claim 7 on data output from an electronic device.

Images