Gas nozzle flow calibration method and device
阅读说明：本技术 燃气喷嘴的流量标定方法及装置 (Gas nozzle flow calibration method and device ) 是由 李旺 于 2019-11-22 设计创作，主要内容包括：本发明涉及一种燃气喷嘴的流量标定方法及装置。流量标定方法包括：获取燃气喷嘴在全工况下的喷嘴出口压力的数据；获取燃气喷嘴的最低燃气压力值；在所述数据中筛选喷嘴出口压力与所述最低燃气压力值的比值大于预设值的数据A；计算超低压工况下的喷嘴入口压力范围；整理出所述数据A、所述喷嘴入口压力范围之间的关系,作为标定依据；控制与燃气喷嘴的出口相连接的第一调压单元,使燃气喷嘴的出口压力等于所述数据A；控制与燃气喷嘴的入口相连接的第二调压单元,使燃气喷嘴的入口压力等于所述喷嘴入口压力范围内的压力值；在出口压力为所述数据A、入口压力为所述压力值的不同组合下,获取对应组合的燃气流量数据,作为燃气流量的标定结果。(The invention relates to a flow calibration method and a flow calibration device for a gas nozzle. The flow calibration method comprises the following steps: acquiring nozzle outlet pressure data of a gas nozzle under all working conditions; acquiring the lowest gas pressure value of the gas nozzle; screening data A of which the ratio of the nozzle outlet pressure to the lowest gas pressure value is greater than a preset value from the data; calculating the pressure range of the nozzle inlet under the ultra-low pressure working condition; the relation between the data A and the pressure range of the nozzle inlet is arranged and used as a calibration basis; controlling a first pressure regulating unit connected with an outlet of the gas nozzle to enable the outlet pressure of the gas nozzle to be equal to the data A; controlling a second pressure regulating unit connected with an inlet of the gas nozzle to enable the inlet pressure of the gas nozzle to be equal to a pressure value within the inlet pressure range of the nozzle; and acquiring gas flow data of corresponding combination as a calibration result of the gas flow under different combinations of the data A of the outlet pressure and the pressure value of the inlet pressure.)
1. A flow calibration method of a gas nozzle is characterized by comprising the following steps:
acquiring nozzle outlet pressure data of a gas nozzle under all working conditions;
acquiring the lowest gas pressure value of the gas nozzle;
screening data A of which the ratio of the nozzle outlet pressure to the lowest gas pressure value is greater than a preset value from the data;
calculating the pressure range of the nozzle inlet under the ultra-low pressure working condition;
the relation between the data A and the pressure range of the nozzle inlet is arranged and used as a calibration basis;
controlling a first pressure regulating unit connected with an outlet of the gas nozzle to enable the outlet pressure of the gas nozzle to be equal to each data in the data A in sequence;
controlling a second pressure regulating unit connected with an inlet of the gas nozzle to enable the inlet pressure of the gas nozzle to be sequentially equal to each pressure value within the inlet pressure range of the nozzle;
and acquiring gas flow data of corresponding combination as a calibration result of the gas flow under different combinations of the outlet pressure of each data in the data A and the inlet pressure of each pressure value.
2. The method for calibrating the flow rate of a gas nozzle according to claim 1, wherein the step of obtaining data of the nozzle outlet pressure of the gas nozzle under the full operating condition comprises:
and (4) carrying out bench experiments on the engine, measuring the outlet pressure of the gas nozzle at different rotating speeds, and recording corresponding measurement data.
3. The method for calibrating the flow rate of a gas nozzle according to claim 1, wherein the step of obtaining the lowest gas pressure value of the gas nozzle comprises:
and determining the lowest gas pressure value of the gas nozzle according to the road spectrum acquisition data of the whole vehicle.
4. The method for calibrating the flow rate of a gas nozzle according to claim 1, wherein the step of calculating the nozzle inlet pressure range under the ultra-low pressure condition comprises:
dividing the data A by the preset value to obtain a corresponding quotient value;
and the interval determined by the lowest gas pressure value and the quotient is the nozzle inlet pressure range under the ultra-low pressure working condition.
5. A flow calibration device of a gas nozzle for implementing a flow calibration method according to any one of claims 1 to 4, characterized in that it comprises:
a gas nozzle;
the gas flowmeter is connected with an inlet of the gas nozzle;
the first pressure regulating unit is arranged at an outlet of the gas nozzle;
the second pressure regulating unit is arranged between the gas nozzle and the gas flowmeter;
and the control unit is electrically connected with the first voltage regulating unit and the second voltage regulating unit.
6. The gas nozzle flow calibration device of claim 5, further comprising:
the first gas pressure sensor is installed between the first pressure regulating unit and the gas nozzle, and the first gas pressure sensor is electrically connected with the control unit.
7. The gas nozzle flow calibration device of claim 6, wherein the first pressure regulating unit is a throttle valve.
8. The gas nozzle flow calibration device of claim 5, further comprising:
and the second fuel gas pressure sensor is arranged between the second pressure regulating unit and the fuel gas nozzle, and is electrically connected with the control unit.
9. The gas nozzle flow calibration device of claim 8, wherein the second pressure regulating unit is a gas pressure regulator.
10. The gas nozzle flow calibration device of claim 5, further comprising a gas supply unit, wherein the gas supply unit comprises:
a liquefied natural gas cylinder;
and the inlet of the vaporizer is connected with the outlet of the liquefied natural gas cylinder, and the outlet of the vaporizer is connected with the inlet of the gas nozzle through the gas flowmeter.
Technical Field
The invention belongs to the technical field of gas engines, and particularly relates to a flow calibration method and device of a gas nozzle.
Background
Gas engines currently use gas nozzles to meter the gas. The flow metering mode of the gas nozzle is as follows: the pressure at the outlet and the pressure ratio at the inlet of the gas nozzle are made smaller than a critical value (typically 0.54), where the ratio is smaller than the critical value, the flow velocity of natural gas at the smallest section of the gas nozzle is the local sound velocity. At the moment, the flow of the natural gas does not change along with the change of the outlet pressure of the gas nozzle, and the flow metering and control of the gas are completed by detecting the temperature and the pressure of the natural gas entering the gas nozzle and controlling the ratio of the opening time and the closing time of the nozzle through a flow calculation formula.
However, in the actual use process, the pressure ratio of the outlet pressure to the inlet pressure of the gas nozzle is often greater than 0.54 (the working condition when the pressure ratio of the outlet pressure to the inlet pressure of the gas nozzle is greater than or equal to 0.54 is called an ultra-low pressure working condition), for example, when LNG is freshly added, the gas pressure is low due to insufficient vaporization of natural gas, and for example, when the engine is suddenly loaded, the gas demand is suddenly increased, and the gas pressure at the inlet of the nozzle is reduced due to slow response of the natural gas pressure regulating device. When the gas flow velocity is lower than the sonic velocity, the gas flow is not only related to the inlet pressure of the gas nozzle, but also related to the outlet pressure of the gas nozzle, and at the moment, the gas flow can deviate according to the original flow calculation formula of natural gas, so that the air-fuel ratio is controlled inaccurately.
Disclosure of Invention
The invention aims to at least solve the problem that the original natural gas flow metering mode is inaccurate when the flow speed in a gas nozzle is lower than the sound speed. The purpose is realized by the following technical scheme:
the invention provides a flow calibration method of a gas nozzle, which comprises the following steps:
acquiring nozzle outlet pressure data of a gas nozzle under all working conditions;
acquiring the lowest gas pressure value of the gas nozzle;
screening data A of which the ratio of the nozzle outlet pressure to the lowest gas pressure value is greater than a preset value from the data;
calculating the pressure range of the nozzle inlet under the ultra-low pressure working condition;
the relation between the data A and the pressure range of the nozzle inlet is arranged and used as a calibration basis;
controlling a first pressure regulating unit connected with an outlet of the gas nozzle to enable the outlet pressure of the gas nozzle to be equal to each data in the data A in sequence;
controlling a second pressure regulating unit connected with an inlet of the gas nozzle to enable the inlet pressure of the gas nozzle to be sequentially equal to each pressure value within the inlet pressure range of the nozzle;
and acquiring gas flow data of corresponding combination as a calibration result of the gas flow under different combinations of the outlet pressure of each data in the data A and the inlet pressure of each pressure value.
According to the flow calibration method of the gas nozzle, the data A of the pressure of the gas nozzle under the ultra-low pressure working condition and the range of the pressure of the gas inlet under the ultra-low pressure working condition are screened out firstly, then the data A and the pressure value in the range of the pressure of the gas inlet under the ultra-low pressure working condition are combined in various ways, and the data of the gas flow passing through the gas nozzle under the corresponding combination are measured, so that the calibration of the gas flow of the gas nozzle under the ultra-low pressure working condition is realized. By using the calibration result, the control precision of the air-fuel ratio of the engine can be improved.
In some embodiments of the invention, the step of obtaining data of nozzle outlet pressure of the gas nozzle under full operating conditions comprises:
and (4) carrying out bench experiments on the engine, measuring the outlet pressure of the gas nozzle at different rotating speeds, and recording corresponding measurement data.
In some embodiments of the invention, the step of obtaining the lowest gas pressure value of the gas nozzle comprises:
and determining the lowest gas pressure value of the gas nozzle according to the road spectrum acquisition data of the whole vehicle.
In some embodiments of the present invention, the step of calculating the nozzle inlet pressure range in the ultra low pressure condition comprises:
dividing the data A by the preset value to obtain a corresponding quotient value;
and the interval determined by the lowest gas pressure value and the quotient is the nozzle inlet pressure range under the ultra-low pressure working condition.
A second aspect of the present invention provides a flow calibration apparatus for a gas nozzle, the flow calibration apparatus being configured to implement the flow calibration method in any one of the above embodiments, the flow calibration apparatus including:
a gas nozzle;
the gas flowmeter is connected with an inlet of the gas nozzle;
the first pressure regulating unit is arranged at an outlet of the gas nozzle;
the second pressure regulating unit is arranged between the gas nozzle and the gas flowmeter;
and the control unit is electrically connected with the first voltage regulating unit and the second voltage regulating unit.
In some embodiments of the present invention, the flow calibration apparatus further includes: the first gas pressure sensor is installed between the first pressure regulating unit and the gas nozzle, and the first gas pressure sensor is electrically connected with the control unit.
In some embodiments of the invention, the first pressure regulating unit is a throttle valve.
In some embodiments of the present invention, the flow calibration apparatus further includes: and the second fuel gas pressure sensor is arranged between the second pressure regulating unit and the fuel gas nozzle, and is electrically connected with the control unit.
In some embodiments of the present invention, the second pressure regulating unit is a gas pressure regulator.
In some embodiments of the present invention, the flow calibration apparatus further comprises a gas supply unit, the gas supply unit comprising: a liquefied natural gas cylinder; and the inlet of the vaporizer is connected with the outlet of the liquefied natural gas cylinder, and the outlet of the vaporizer is connected with the inlet of the gas nozzle through the gas flowmeter.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like parts are designated by like reference numerals throughout the drawings. In the drawings:
FIG. 1 is a schematic flow chart of a method for calibrating the flow rate of a gas nozzle according to an embodiment of the present invention;
fig. 2 is a schematic view of a flow calibration device of a gas nozzle according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "including," and "having" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and/or groups thereof.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as "first," "second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
For convenience of description, spatially relative terms, such as "inner", "outer", "lower", "below", "upper", "above", and the like, may be used herein to describe one element or feature's relationship to another element or feature as illustrated in the figures. Such spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" or "over" the other elements or features. Thus, the example term "below … …" can include both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
As shown in fig. 1, an embodiment of the first aspect of the present invention provides a method for calibrating a flow rate of a gas nozzle, including:
s101: acquiring nozzle outlet pressure data of a gas nozzle under all working conditions;
s102: acquiring the lowest gas pressure value of the gas nozzle;
s103: screening data A of which the ratio of the nozzle outlet pressure to the lowest gas pressure value is greater than a preset value from the data;
s104: calculating the pressure range of the nozzle inlet under the ultra-low pressure working condition;
s105: the relation between the data A and the pressure range of the nozzle inlet is arranged and used as a calibration basis;
s106: controlling a first pressure regulating unit connected with an outlet of the gas nozzle to enable the outlet pressure of the gas nozzle to be equal to each data in the data A in sequence;
s107: controlling a second pressure regulating unit connected with an inlet of the gas nozzle to enable the inlet pressure of the gas nozzle to be sequentially equal to each pressure value within the inlet pressure range of the nozzle;
s108: and acquiring gas flow data of corresponding combination as a calibration result of the gas flow under different combinations of the outlet pressure of each data in the data A and the inlet pressure of each pressure value.
According to the flow calibration method of the gas nozzle, the data A of the pressure of the gas nozzle under the ultra-low pressure working condition and the range of the pressure of the gas inlet under the ultra-low pressure working condition are screened out firstly, then the data A and the pressure value in the range of the pressure of the gas inlet under the ultra-low pressure working condition are combined in various ways, and the data of the gas flow passing through the gas nozzle under the corresponding combination are measured, so that the calibration of the gas flow of the gas nozzle under the ultra-low pressure working condition is realized. By using the calibration result, the control precision of the air-fuel ratio of the engine can be improved.
Specifically, the ECU can judge the working condition of the gas nozzle by monitoring the outlet pressure of the gas nozzle, when the gas flow speed inside the gas nozzle is judged to be the sound speed, the gas flow characteristic is only related to the inlet pressure and the temperature of the gas nozzle, and the power-on time of the nozzle is calculated according to the gas demand flow and the gas sound speed injection characteristic. When the gas flow speed in the gas nozzle is judged to be lower than the sonic speed (namely under the ultra-low pressure working condition), the gas flow characteristic is related to the inlet pressure, the temperature and the outlet pressure of the nozzle, and the nozzle power-on time is calculated according to the flow demand and the gas subsonic flow characteristic (namely the calibrated flow characteristic).
In some embodiments of the invention, the step of obtaining data of nozzle outlet pressure of the gas nozzle under full operating conditions comprises:
and (4) carrying out bench experiments on the engine, measuring the outlet pressure of the gas nozzle at different rotating speeds, and recording corresponding measurement data.
In this embodiment, the data of the nozzle outlet pressure under the full operating condition of the gas nozzle can be obtained through the bench test of the engine.
In some embodiments of the invention, the step of obtaining the lowest gas pressure value of the gas nozzle comprises:
and determining the lowest gas pressure value of the gas nozzle according to the road spectrum acquisition data of the whole vehicle.
In some embodiments of the present invention, the step of calculating the nozzle inlet pressure range in the ultra low pressure condition comprises:
dividing the data A by the preset value to obtain a corresponding quotient value;
and the interval determined by the lowest gas pressure value and the quotient is the nozzle inlet pressure range under the ultra-low pressure working condition.
As shown in fig. 2, an embodiment of the second aspect of the present invention provides a flow calibration apparatus for a gas nozzle, and the flow calibration apparatus is used for implementing the flow calibration method in any of the above embodiments. Specifically, the flow calibration device comprises a
According to the flow calibration device of the gas nozzle, the control unit can enable the outlet pressure of the gas nozzle to be equal to the data A through the first pressure regulating unit, the control unit can enable the inlet pressure of the gas nozzle to be equal to the pressure value within the inlet pressure range of the nozzle through controlling the second pressure regulating unit, and gas flow data of the gas nozzle under different combinations of the outlet pressure and the inlet pressure can be obtained through the
In some embodiments of the present invention, the flow calibration apparatus further includes a first
In some embodiments of the invention, the first
In some embodiments of the present invention, the flow calibration apparatus further includes a second
In some embodiments of the present invention, the second
In some embodiments of the present invention, the flow calibration apparatus further comprises a gas supply unit, the gas supply unit comprises a liquefied
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
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