CN116398309A - Natural gas engine control method and system based on intake air humidity and vehicle - Google Patents

Natural gas engine control method and system based on intake air humidity and vehicle Download PDF

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Publication number
CN116398309A
CN116398309A CN202310659429.0A CN202310659429A CN116398309A CN 116398309 A CN116398309 A CN 116398309A CN 202310659429 A CN202310659429 A CN 202310659429A CN 116398309 A CN116398309 A CN 116398309A
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Prior art keywords
air
intake
engine control
engine
intake air
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Inventor
付超
魏广杰
李海牧
郁文通
杨琨明
洪彬彬
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Jiangling Motors Corp Ltd
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Jiangling Motors Corp Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D41/0027—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures the fuel being gaseous
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D29/00—Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto
    • F02D29/02—Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
    • F02D41/0047—Controlling exhaust gas recirculation [EGR]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D41/222—Safety or indicating devices for abnormal conditions relating to the failure of sensors or parameter detection devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/3005—Details not otherwise provided for
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P5/00—Advancing or retarding ignition; Control therefor
    • F02P5/04—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions
    • F02P5/045—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions combined with electronic control of other engine functions, e.g. fuel injection
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P5/00—Advancing or retarding ignition; Control therefor
    • F02P5/04—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions
    • F02P5/145—Advancing or retarding ignition; Control therefor automatically, as a function of the working conditions of the engine or vehicle or of the atmospheric conditions using electrical means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/04—Engine intake system parameters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/04—Engine intake system parameters
    • F02D2200/0414—Air temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/04—Engine intake system parameters
    • F02D2200/0418—Air humidity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/30—Use of alternative fuels, e.g. biofuels

Abstract

The invention relates to the technical field of engines, in particular to a natural gas engine control method and system based on intake air humidity and a vehicle. The method comprises the steps of acquiring characteristic parameters of intake air by using an intake system, transmitting the characteristic parameters to an engine control system, and obtaining the dry air quantity and the steam quantity in the intake air after numerical filtering and calculation processing; and (3) optimizing and controlling the air rail air injection quantity, the ignition control signal and the external exhaust gas recirculation pipeline based on the dry air quantity in the air. According to the invention, through adopting the intake dry air quantity and intake water vapor quantity parameter control, the humidity difference can be effectively removed, and the condition that the bench performance and the whole vehicle use performance are inconsistent due to the intake humidity is avoided. Meanwhile, in the aspect of engine parameter control, the fuel gas quantity can be effectively and accurately controlled, the output ignition angle is optimized, the effective exhaust gas recirculation quantity is corrected, and the integral performance of the engine is improved.

Description

Natural gas engine control method and system based on intake air humidity and vehicle
Technical Field
The invention relates to the technical field of engines, in particular to a natural gas engine control method and system based on intake air humidity and a vehicle.
Background
The main fuels of natural gas engines are liquefied natural gas (Liquefied Natural Gas, LNG) and compressed natural gas (Compressed Natural Gas, CNG), the main component of which is methane (CH 4), and the main products of the engine after participating in combustion are water (H2O) and carbon dioxide (CO 2). The current national VI natural gas engine systems mainly adopt intake manifold single-point injection, equivalent combustion and exhaust gas recirculation (Exhaust Gas Return, EGR) technology, wherein the EGR technology mainly comprises that combustion exhaust gas flows into the intake manifold after being cooled by an external EGR pipeline, and then participates in the combustion process again. The combustion exhaust gas contains a large amount of water vapor, and the intake fresh air also contains a certain amount of water vapor. On the one hand, the reduction of the actual effective air quantity caused by the water vapor in the air intake influences the torque output and the performance consistency of the engine, and on the other hand, the control of the EGR quantity is influenced by the action of the water vapor in the air intake, so that the working efficiency of the engine is reduced.
In addition, the model calibration of the existing natural gas engine control system is carried out on a bench of a laboratory, the air inlet humidity is in a certain range, and the bench calibration result cannot adapt to various use conditions of different humidities in different areas and climates.
Disclosure of Invention
The present invention aims to at least ameliorate one of the technical problems of the prior art. Therefore, the invention provides a natural gas engine control method and system based on intake air humidity and a vehicle.
According to an embodiment of the first aspect of the invention, a natural gas engine control method based on intake air humidity comprises the following steps:
step S100, a natural gas engine control scene based on air inlet humidity is built, wherein a signal acquisition device is arranged in a front pipeline of a throttle of an engine, the signal acquisition device comprises an air inlet flow sensor, a temperature sensor, a pressure sensor and a humidity sensor, and the air inlet flow sensor, the temperature sensor, the pressure sensor and the humidity sensor are electrically connected with a signal input end of an engine control system;
step S200, acquiring characteristic parameters of intake air by using a signal acquisition device and transmitting the characteristic parameters to an engine control system;
step S300, the engine control system carries out numerical filtering and calculation processing on the characteristic parameters of the intake air to obtain the dry air quantity and the steam quantity in the intake air;
step S400, optimizing control of the air rail air injection quantity and the ignition control signal is completed based on the dry air quantity in the intake air;
step S500, optimizing control of an external exhaust gas recirculation pipeline is completed based on the steam amount in the intake air;
in step S600, the natural gas engine control process based on the intake air humidity ends.
According to the natural gas engine control method based on the air inlet humidity, provided by the embodiment of the invention, the humidity difference can be effectively removed by adopting the air inlet dry air quantity and the air inlet water vapor quantity parameter control, and the condition that the bench performance caused by the air inlet humidity is inconsistent with the whole vehicle use performance is avoided. Meanwhile, in the aspect of engine parameter control, the fuel gas quantity can be effectively and accurately controlled, the output ignition angle is optimized, the effective EGR is corrected, and the integral performance of the engine is improved. Compared with the prior art, the method has the advantages that the system operation fluctuation is reduced, the engine torque is ensured to be enough, the performance is stable, the environmental adaptability is improved, and the like in the aspects of optimizing the engine combustion parameters.
In a possible implementation manner of the first aspect, the specific process of step S300 is that the engineThe control system acquires the moisture content of the air inlet according to the temperature, the pressure and the relative humidity of the air inlet acquired by the signal acquisition device through the following formula
Figure SMS_1
：
Figure SMS_2
，
Wherein, 0.622 is a constant value,
Figure SMS_3
is the relative humidity value, ">
Figure SMS_4
For the intake air pressure value, +.>
Figure SMS_5
The saturated vapor pressure value of the air inlet is mapped with the temperature of the air inlet, and can be obtained by looking up a table in an engine control system according to the temperature of the air inlet;
by the moisture content of the intake air
Figure SMS_6
Obtaining the mass fraction of water vapor in the intake air>
Figure SMS_7
：
Figure SMS_8
，
Wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_9
is the moisture content of the intake air;
intake air mass flow based on signal acquisition device
Figure SMS_10
And the mass fraction of water vapor->
Figure SMS_11
Acquiring the amount of dry air in the intake air>
Figure SMS_12
And water vapor amount->
Figure SMS_13
：
Figure SMS_14
，
Figure SMS_15
，
Wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_16
for intake air mass flow,/->
Figure SMS_17
Is the mass fraction of the water vapor.
In a possible implementation manner of the first aspect, in step S400, the performing the optimization control of the air rail injection amount based on the dry air amount in the intake air includes calculating the fuel gas amount, specifically:
and calculating the dry air quantity of the air intake according to the theoretical air-fuel ratio in the equivalent combustion mode to obtain the theoretical air quantity, and correcting and calculating to obtain the target air quantity through negative feedback adjustment of an oxygen sensor signal on an engine exhaust pipe, wherein an engine control system is in communication interaction with a natural gas system, and the power-on time of an air rail in the natural gas system is controlled to realize the optimal control of the air injection quantity of the air rail. Compared with the prior art, the invention eliminates the influence of intake steam, so that the fuel gas amount is more accurate, and the control simplicity of the air-fuel ratio lambda (the ratio of the actual air-fuel ratio to the set air-fuel ratio) is improved to a certain extent.
In a possible implementation manner of the first aspect, in step S400, performing the optimal control of the ignition control signal based on the amount of dry air in the intake air includes calculating an ignition angle, specifically:
and according to the received engine rotating speed signal and the air quantity signal in the air inlet, the engine control system acquires the two-dimensional chart and outputs the two-dimensional chart to obtain the ignition angle of the engine, and the ignition angle is output through the ignition control of the engine control system, so that the optimal control of the ignition control signal is realized. The intake dry air quantity is a key signal affecting the actual combustion condition, and the ignition angle is controlled in real time by taking the intake dry air quantity as a reference and combining the engine speed, so that the engine can be ensured to work at a better ignition angle, the torque output is improved, and the fuel gas consumption is reduced.
In a possible implementation manner of the first aspect, in step S500, the performing of the optimal control of the external exhaust gas recirculation line based on the amount of water vapor in the intake air includes calculating an external exhaust gas recirculation amount of the engine, specifically:
according to the engine control system, the received engine speed signal and the air quantity signal in the air inlet are collected, a two-dimensional chart is inquired to obtain the target external exhaust gas recirculation quantity of the engine, the water vapor quantity in the air inlet is subtracted from the target external exhaust gas recirculation quantity, and the external exhaust gas recirculation quantity of the actual requirement can be obtained, wherein the formula is as follows:
Figure SMS_18
，
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_19
for the actual required external exhaust gas recirculation quantity, +.>
Figure SMS_20
For the target external exhaust gas recirculation amount, +.>
Figure SMS_21
Is the water vapor amount in the intake air;
the engine control system controls the exhaust gas recirculation system to output the external exhaust gas recirculation quantity which is actually required, so that the external exhaust gas recirculation pipeline is optimally controlled.
In a possible implementation manner of the first aspect, the step S400 and the step S500 are not sequential.
According to a second aspect of the present invention, a natural gas engine control system based on intake air humidity, wherein the system is configured to execute the control method described above, includes:
the engine control system and the air inlet manifold connected with the engine control system are used for realizing combustion control of the engine;
the exhaust gas recirculation system is connected with the engine control system and used for providing water vapor to correct the exhaust gas recirculation amount, the exhaust gas recirculation system is connected with the air inlet manifold and is in communication connection with the engine control system through a CAN bus and used for realizing the optimal control of an external exhaust gas recirculation pipeline;
the air intake system is connected with the air intake manifold and is in communication connection with the engine control system through a CAN bus and used for measuring and controlling air intake, wherein the air intake system comprises a signal acquisition device, and the signal acquisition device is connected with the engine control system CAN bus;
the natural gas system is connected with the air inlet manifold and is in communication connection with the engine control system through the CAN bus and used for realizing optimal control of the gas injection quantity of the gas rail.
In a possible implementation manner of the second aspect, the signal acquisition device includes an intake air flow sensor, a temperature sensor, a pressure sensor and a humidity sensor, where the intake air flow sensor, the temperature sensor, the pressure sensor and the humidity sensor are all electrically connected with a signal input terminal of the engine control system.
In a possible implementation manner of the second aspect, the engine control system performs fault determination and signal validity detection operations on the intake air flow sensor, the temperature sensor, the pressure sensor and the humidity sensor to ensure reliability of normal operation of the system.
According to a third aspect of the invention, a vehicle is provided that includes an optimized operation of a natural gas engine using the control method described above.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a natural gas engine control method based on intake air humidity according to an embodiment of the present invention;
FIG. 2 is a block diagram of a natural gas engine control system based on intake air humidity in accordance with an embodiment of the present invention.
Detailed Description
The following detailed description of embodiments of the present invention is exemplary, with reference to the accompanying drawings, it being understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit the application.
It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
The terms "first," second, "" third and the like in the description and in the claims and drawings are used for distinguishing between different objects and not for describing a particular sequential order. Furthermore, the terms "comprising," "including," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion. For example, a series of steps or elements may be included, or alternatively, steps or elements not listed or, alternatively, other steps or elements inherent to such process, method, article, or apparatus may be included.
Only some, but not all, of the matters relevant to the present application are shown in the accompanying drawings. Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flowcharts. Although a flowchart depicts operations (or steps) as a sequential process, many of the operations can be performed in parallel, concurrently, or at the same time. Furthermore, the order of the operations may be rearranged. The process may be terminated when its operations are completed, but may have additional steps not included in the figures. The processes may correspond to methods, functions, procedures, subroutines, and the like.
As used in this specification, the terms "component," "module," "system," "unit," and the like are intended to refer to a computer-related entity, either hardware, firmware, a combination of hardware and software, or software in execution. For example, a unit may be, but is not limited to being, a process running on a processor, an object, an executable, a thread of execution, a program, and/or being distributed between two or more computers. Furthermore, these units may be implemented from a variety of computer-readable media having various data structures stored thereon. The units may communicate by way of local and/or remote processes such as in accordance with a signal having one or more data packets (e.g., second unit data from another unit interacting with a local system, distributed system, and/or across a network).
Example 1
Referring to fig. 1, the present embodiment provides a natural gas engine control method based on intake air humidity, which includes:
step S100, a natural gas engine control scene based on air inlet humidity is built, wherein a signal acquisition device is arranged in a pipeline in front of a throttle of the engine. The signal acquisition device comprises an air inlet flow sensor, a temperature sensor, a pressure sensor and a humidity sensor, wherein the air inlet flow sensor, the temperature sensor, the pressure sensor and the humidity sensor are all electrically connected with the signal input end of the engine control system;
step S200, acquiring air characteristic parameters of the inlet air by utilizing a signal acquisition device and transmitting the air characteristic parameters to an engine control system, wherein the air characteristic parameters comprise inlet air flow, temperature, pressure, humidity and the like;
step S300, the engine control system carries out numerical filtering and calculation processing on the characteristic parameters of the intake air to obtain the dry air quantity and the steam quantity in the intake air;
step S400, optimizing control of the air rail air injection quantity and the ignition control signal is completed based on the dry air quantity in the intake air;
step S500, optimizing control of an external exhaust gas recirculation pipeline is completed based on the steam amount in the intake air;
in step S600, the natural gas engine control process based on the intake air humidity ends.
According to the natural gas engine control method based on the air inlet humidity, provided by the embodiment of the invention, the humidity difference can be effectively removed by adopting the air inlet dry air quantity and the air inlet water vapor quantity parameter control, and the condition that the bench performance caused by the air inlet humidity is inconsistent with the whole vehicle use performance is avoided. Meanwhile, in the aspect of engine parameter control, the fuel gas quantity can be effectively and accurately controlled, the output ignition angle is optimized, the effective EGR is corrected, and the integral performance of the engine is improved. Compared with the prior art, the method has the advantages that the system operation fluctuation is reduced, the engine torque is ensured to be enough, the performance is stable, the environmental adaptability is improved, and the like in the aspects of optimizing the engine combustion parameters.
Specifically, the steps ofThe specific process of S300 is that the engine control system obtains the moisture content of the air inlet according to the temperature, pressure and relative humidity of the air inlet acquired by the signal acquisition device by the following formula
Figure SMS_22
：
Figure SMS_23
，
Wherein, 0.622 is a constant value,
Figure SMS_24
is a relative humidity value, a percentage value, < + >>
Figure SMS_25
For the intake air pressure value, +.>
Figure SMS_26
The saturated vapor pressure value of the air inlet is mapped with the temperature of the air inlet, and can be obtained by looking up a table in an engine control system according to the temperature of the air inlet;
by the moisture content of the intake air
Figure SMS_27
Obtaining the mass fraction of water vapor in the intake air>
Figure SMS_28
：
Figure SMS_29
，
Wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_30
is the moisture content of the intake air;
intake air mass flow based on signal acquisition device
Figure SMS_31
And the mass fraction of water vapor->
Figure SMS_32
Acquiring the amount of dry air in the intake air>
Figure SMS_33
And water vapor amount->
Figure SMS_34
：
Figure SMS_35
，
Figure SMS_36
，
Wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_37
for intake air mass flow,/->
Figure SMS_38
Is the mass fraction of the water vapor.
The engine control system calculates the dry air quantity and the steam quantity in the intake air according to the intake air flow, the temperature, the pressure and the humidity. Compared with the prior wet air quantity, the dry air quantity can more directly reflect the air quantity participating in combustion, and the control of the system working parameters is more accurate. In the natural gas engine control system of the present invention, therefore, the dry air amount is used as the effective air amount of the engine for the combustion calculation of the subsequent engine. Meanwhile, when the maximum air quantity of the engine is limited to a certain value, the effective air quantity is selected for limit value judgment, so that the stable and consistent performance of the engine can be ensured.
Specifically, in step S400, the completion of the optimal control of the gas rail injection amount based on the amount of dry air in the intake air includes calculation of the gas amount, specifically:
and calculating the dry air quantity of the air intake according to the theoretical air-fuel ratio in the equivalent combustion mode to obtain the theoretical air quantity, and correcting and calculating to obtain the target air quantity through negative feedback adjustment of an oxygen sensor signal on an engine exhaust pipe, wherein an engine control system is in communication interaction with a natural gas system, and the power-on time of an air rail in the natural gas system is controlled to realize the optimal control of the air injection quantity of the air rail. Compared with the prior art, the invention eliminates the influence of intake steam, so that the fuel gas amount is more accurate, and the control simplicity of the air-fuel ratio lambda (the ratio of the actual air-fuel ratio to the set air-fuel ratio) is improved to a certain extent.
Specifically, in step S400, the completion of the optimal control of the ignition control signal based on the amount of dry air in the intake air includes the calculation of the ignition angle, specifically:
and according to the received engine rotating speed signal and the air quantity signal in the air inlet, the engine control system acquires the two-dimensional chart and outputs the two-dimensional chart to obtain the ignition angle of the engine, and the ignition angle is output through the ignition control of the engine control system, so that the optimal control of the ignition control signal is realized. The intake dry air quantity is a key signal affecting the actual combustion condition, and the ignition angle is controlled in real time by taking the intake dry air quantity as a reference and combining the engine speed, so that the engine can be ensured to work at a better ignition angle, the torque output is improved, and the fuel gas consumption is reduced.
Specifically, in step S500, the completion of the optimal control of the external exhaust gas recirculation line based on the amount of water vapor in the intake air includes calculation of the external exhaust gas recirculation amount of the engine, which corresponds to an increase in the external exhaust gas recirculation amount, since water vapor in the intake air flows into the engine cylinder, functioning as exhaust gas recirculation together with the combustion exhaust gas. Engine performance is very sensitive to the amount of exhaust gas recirculation, and therefore it is necessary to take into account the correction of the external amount of exhaust gas recirculation by the amount of intake water vapor. The method comprises the following steps:
according to the engine control system, the received engine speed signal and the air quantity signal in the air inlet are collected, a two-dimensional chart is inquired to obtain the target external exhaust gas recirculation quantity of the engine, the water vapor quantity in the air inlet is subtracted from the target external exhaust gas recirculation quantity, and the external exhaust gas recirculation quantity of the actual requirement can be obtained, wherein the formula is as follows:
Figure SMS_39
，
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure SMS_40
for the actual required external exhaust gas recirculation quantity, +.>
Figure SMS_41
For the target external exhaust gas recirculation amount, +.>
Figure SMS_42
Is the water vapor amount in the intake air;
the engine control system controls the exhaust gas recirculation system to output the external exhaust gas recirculation quantity which is actually required, so that the external exhaust gas recirculation pipeline is optimally controlled.
It should be noted that, in this embodiment, there is no sequence of the step S400 and the step S500.
According to the invention, through increasing the measurement of the air intake humidity of the engine and matching with other sensor signals on the engine, the dry air quantity participating in combustion and the water vapor quantity serving as EGR are calculated in an internal logic algorithm of an engine control system, so that the key parameters of the engine are corrected, the performance consistency of the engine is ensured, and the oil saving effect of the engine is improved. Meanwhile, the invention has flexible scheme, simple structure and relatively simplified system parameter control, and can adapt to the use requirements of various engines such as supercharging, non-supercharging and the like under different environments.
Example 2
Referring to fig. 2, the present embodiment provides a natural gas engine control system based on intake air humidity, where the system is configured to execute the above control method, and includes:
the engine control system and the air inlet manifold connected with the engine control system are used for realizing combustion control of the engine;
the exhaust gas recirculation system is connected with the engine control system and used for providing water vapor to correct the exhaust gas recirculation amount, the exhaust gas recirculation system is connected with the air inlet manifold and is in communication connection with the engine control system through a CAN bus and used for realizing the optimal control of an external exhaust gas recirculation pipeline;
the air intake system is connected with the air intake manifold and is in communication connection with the engine control system through a CAN bus and used for measuring and controlling air intake, wherein the air intake system comprises a signal acquisition device, and the signal acquisition device is connected with the engine control system CAN bus;
the natural gas system is connected with the air inlet manifold and is in communication connection with the engine control system through the CAN bus and used for realizing optimal control of the gas injection quantity of the gas rail.
Specifically, the signal acquisition device comprises an air inlet flow sensor, a temperature sensor, a pressure sensor and a humidity sensor, wherein the air inlet flow sensor, the temperature sensor, the pressure sensor and the humidity sensor are electrically connected with a signal input end of an engine control system.
Specifically, the engine control system performs a failure determination and signal validity detection operation on the intake air flow sensor, the temperature sensor, the pressure sensor, and the humidity sensor to ensure the reliability of the normal operation of the system.
Example 3
The embodiment provides a vehicle, wherein the vehicle comprises the natural gas engine optimized by adopting the control method.
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the invention.
In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples.
It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present application. Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application for the embodiment. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those of skill in the art will explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: many changes, modifications, substitutions and variations may be made to the embodiments without departing from the spirit and principles of the invention, the scope of which is defined by the claims and their equivalents.

Claims (10)

1. A method for controlling a natural gas engine based on intake air humidity, comprising:
step S100, a natural gas engine control scene based on air inlet humidity is built, wherein a signal acquisition device is arranged in a front pipeline of a throttle of an engine and comprises an air inlet flow sensor, a temperature sensor, a pressure sensor and a humidity sensor, and the air inlet flow sensor, the temperature sensor, the pressure sensor and the humidity sensor are electrically connected with a signal input end of an engine control system;
step S200, acquiring characteristic parameters of intake air by using a signal acquisition device and transmitting the characteristic parameters to an engine control system;
step S300, the engine control system carries out numerical filtering and calculation processing on the characteristic parameters of the intake air to obtain the dry air quantity and the steam quantity in the intake air;
step S400, optimizing control of the air rail air injection quantity and the ignition control signal is completed based on the dry air quantity in the intake air;
step S500, optimizing control of an external exhaust gas recirculation pipeline is completed based on the steam amount in the intake air;
in step S600, the natural gas engine control process based on the intake air humidity ends.
2. The method for controlling a natural gas engine based on intake air humidity according to claim 1, wherein the specific process of step S300 is: the engine control system obtains the moisture content of the air inlet according to the temperature, the pressure and the relative humidity of the air inlet acquired by the signal acquisition device by the following formula
Figure QLYQS_1
：
Figure QLYQS_2
，
Wherein, 0.622 is a constant value,
Figure QLYQS_3
is the relative humidity value, ">
Figure QLYQS_4
For the intake air pressure value, +.>
Figure QLYQS_5
A saturated vapor pressure value for intake air;
by the moisture content of the intake air
Figure QLYQS_6
Obtaining the mass fraction of water vapor in the intake air>
Figure QLYQS_7
：
Figure QLYQS_8
，
Wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure QLYQS_9
is the moisture content of the intake air;
intake air mass flow based on signal acquisition device
Figure QLYQS_10
And the mass fraction of water vapor->
Figure QLYQS_11
Acquiring the amount of dry air in the intake air>
Figure QLYQS_12
And water vapor amount->
Figure QLYQS_13
：
Figure QLYQS_14
，
Figure QLYQS_15
，
Wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure QLYQS_16
for intake air mass flow,/->
Figure QLYQS_17
Is the mass fraction of the water vapor.
3. The intake air humidity-based natural gas engine control method according to claim 1, wherein in step S400, the completion of the optimal control of the gas rail injection amount based on the amount of dry air in the intake air includes calculation of the gas amount, specifically:
and calculating the dry air quantity of the air intake according to the theoretical air-fuel ratio in the equivalent combustion mode to obtain the theoretical air quantity, and correcting and calculating to obtain the target air quantity through negative feedback adjustment of an oxygen sensor signal on an engine exhaust pipe, wherein an engine control system is in communication interaction with a natural gas system, and the power-on time of an air rail in the natural gas system is controlled to realize the optimal control of the air injection quantity of the air rail.
4. The intake air humidity-based natural gas engine control method according to claim 1, wherein in step S400, the completion of the optimal control of the ignition control signal based on the amount of dry air in the intake air includes an ignition angle calculation, specifically:
and according to the received engine rotating speed signal and the air quantity signal in the air inlet, the engine control system acquires the two-dimensional chart and outputs the two-dimensional chart to obtain the ignition angle of the engine, and the ignition angle is output through the ignition control of the engine control system, so that the optimal control of the ignition control signal is realized.
5. The intake air humidity-based natural gas engine control method according to claim 1, wherein in step S500, the completion of the optimal control of the external exhaust gas recirculation line based on the amount of water vapor in the intake air includes calculation of the engine external exhaust gas recirculation amount, specifically:
according to the engine control system, the received engine speed signal and the air quantity signal in the air inlet are collected, a two-dimensional chart is inquired to obtain the target external exhaust gas recirculation quantity of the engine, the water vapor quantity in the air inlet is subtracted from the target external exhaust gas recirculation quantity, and the external exhaust gas recirculation quantity of the actual requirement can be obtained, wherein the formula is as follows:
Figure QLYQS_18
，
wherein, the liquid crystal display device comprises a liquid crystal display device,
Figure QLYQS_19
for the actual required external exhaust gas recirculation quantity, +.>
Figure QLYQS_20
For the target external exhaust gas recirculation amount,
Figure QLYQS_21
is the water vapor amount in the intake air;
the engine control system controls the exhaust gas recirculation system to output the external exhaust gas recirculation quantity which is actually required, so that the external exhaust gas recirculation pipeline is optimally controlled.
6. The intake air humidity based natural gas engine control method according to claim 1, wherein step S400 and step S500 are not sequential.
7. A natural gas engine control system based on intake air humidity, characterized in that the system is adapted to perform the control method according to any one of claims 1 to 6, comprising:
the engine control system and the air inlet manifold connected with the engine control system are used for realizing combustion control of the engine;
the exhaust gas recirculation system is connected with the engine control system and used for providing water vapor to correct the exhaust gas recirculation amount, the exhaust gas recirculation system is connected with the air inlet manifold and is in communication connection with the engine control system through a CAN bus and used for realizing the optimal control of an external exhaust gas recirculation pipeline;
the air intake system is connected with the air intake manifold and is in communication connection with the engine control system through a CAN bus and used for measuring and controlling air intake, wherein the air intake system comprises a signal acquisition device, and the signal acquisition device is connected with the engine control system CAN bus;
the natural gas system is connected with the air inlet manifold and is in communication connection with the engine control system through the CAN bus and used for realizing optimal control of the gas injection quantity of the gas rail.
8. The air intake humidity based natural gas engine control system of claim 7 wherein the signal acquisition device comprises an air intake flow sensor, a temperature sensor, a pressure sensor, and a humidity sensor, wherein the air intake flow sensor, the temperature sensor, the pressure sensor, and the humidity sensor are all electrically connected to the engine control system signal input.
9. The intake air humidity based natural gas engine control system according to claim 8, wherein the engine control system performs a malfunction determination and signal validity detection operation on the intake air flow sensor, the temperature sensor, the pressure sensor, and the humidity sensor to ensure reliability of normal operation of the system.
10. A vehicle comprising an optimized operation of a natural gas engine using the control method of any one of claims 1 to 6.
CN202310659429.0A 2023-06-06 2023-06-06 Natural gas engine control method and system based on intake air humidity and vehicle Pending CN116398309A (en)

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US20120024271A1 (en) * 2010-04-21 2012-02-02 GM Global Technology Operations LLC Method for managing the relative humidity in the air path of an internal combustion engine equipped with a low pressure egr system
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