CN114233502A - Control method and device for gas proportional valve of natural gas engine - Google Patents

Control method and device for gas proportional valve of natural gas engine Download PDF

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Publication number
CN114233502A
CN114233502A CN202111593479.0A CN202111593479A CN114233502A CN 114233502 A CN114233502 A CN 114233502A CN 202111593479 A CN202111593479 A CN 202111593479A CN 114233502 A CN114233502 A CN 114233502A
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proportional valve
valve
zero
gas proportional
gas
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CN202111593479.0A
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CN114233502B (en
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张楠
孙克
李忠信
张国强
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Weichai Power Co Ltd
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Weichai Power Co 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
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/2406—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using essentially read only memories
    • F02D41/2425—Particular ways of programming the data
    • F02D41/2429—Methods of calibrating or learning
    • F02D41/2432—Methods of calibration
    • 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
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D41/221—Safety or indicating devices for abnormal conditions relating to the failure of actuators or electrically driven elements
    • 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
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/2406—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using essentially read only memories
    • F02D41/2425—Particular ways of programming the data
    • F02D41/2429—Methods of calibrating or learning
    • F02D41/2441—Methods of calibrating or learning characterised by the learning conditions
    • F02D41/2445—Methods of calibrating or learning characterised by the learning conditions characterised by a plurality of learning conditions or ranges
    • 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
    • F02D2041/224—Diagnosis of the fuel system
    • 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
    • Y02T10/40—Engine management systems

Abstract

The invention provides a method and a device for controlling a gas proportional valve of a natural gas engine, wherein the method comprises the following steps: judging whether the gas proportional valve meets the self-learning condition of the zero position at present; if yes, determining to detect the current valve closing accumulated times of the gas proportional valve; judging whether the current accumulated valve closing times are larger than a preset valve closing threshold value or not; if the current accumulated valve closing times are larger than a preset valve closing threshold, correcting the gas proportional valve when the current actual closing position of the gas proportional valve is detected to be within the zero position threshold range; therefore, the opening degree of the gas proportional valve can be corrected under the condition of zero offset, so that the gas proportional valve can still provide proper and correct gas supply flow, gas leakage and pipeline blockage are prevented, the problem of fault misinformation is reduced, and the gas proportional valve is more comprehensive and accurate compared with the existing control strategy.

Description

Control method and device for gas proportional valve of natural gas engine
Technical Field
The invention belongs to the technical field of gas proportional valve control, and particularly relates to a method and a device for controlling a gas proportional valve of a natural gas engine.
Background
The existing gas proportional valve of the natural gas engine cannot carry out reasonable electric control logic control on the opening and closing positions of gas, so that the problems of inaccurate gas supply flow control, untight sealing of the closing position of the gas proportional valve and the like are easily caused.
Under the condition of complex application environment, the pipeline pressure required by the gas injection valve is too high, so that the pipeline leakage is easily caused, and the gas nozzle is easily blocked by impurities, so that the failure rate of the gas injection valve and the pipeline thereof in the market is high; and the existing electric control logic cannot carry out quick and effective monitoring control on the opening and closing of the fuel gas proportional valve.
Disclosure of Invention
In view of the above, the present invention provides a method and an apparatus for controlling a gas proportional valve of a natural gas engine, which are used for correcting the opening of the gas proportional valve under the condition of zero offset of the gas proportional valve, so that the gas proportional valve can still provide a proper and correct gas supply flow, prevent gas leakage and pipeline blockage, and reduce the problem of false alarm.
The application discloses in a first aspect a natural gas engine gas proportional valve control method, including:
judging whether the gas proportional valve meets the self-learning condition of the zero position at present;
if yes, determining to detect the current valve closing accumulated times of the gas proportional valve;
judging whether the current accumulated valve closing times are larger than a preset valve closing threshold value or not;
and if the current accumulated valve closing times are larger than the preset valve closing threshold, correcting the gas proportional valve when the current actual closing position of the gas proportional valve is detected to be within the zero position threshold range.
Optionally, in the method for controlling a gas proportional valve of a natural gas engine, the modifying the gas proportional valve includes:
judgment of yn-znWhether it is greater than a zero offset threshold;
if so, then z is determinedn＝zn-1+ D; if not, determining zn＝yn；
Determination of wn＝xn-zn；
Wherein D is a zero offset threshold; y isnThe second parameter is the second parameter when the valve is closed for the nth time; z is a radical ofnThe zero self-learning value is the zero self-learning value when the valve is closed for the nth time; z is a radical ofn-1The zero self-learning value is the zero self-learning value when the valve is closed for the (n-1) th time; w is anThe valve zero correction value is the valve zero correction value at the time of the nth valve closing.
Optionally, in the above method for controlling a gas proportional valve of a natural gas engine, the second parameter is a current actual closing position of the gas proportional valve.
Optionally, in the method for controlling a gas proportional valve of a natural gas engine, after determining whether the current accumulated number of valve closing times is greater than a preset valve closing threshold, if the current accumulated number of valve closing times is greater than the preset valve closing threshold, the method further includes:
and when the current actual closing position of the gas proportional valve is detected to be out of the zero position threshold range, judging that the gas proportional valve has zero offset fault.
Optionally, in the method for controlling a gas proportional valve of a natural gas engine, after determining whether the current accumulated number of valve closing times is greater than a preset valve closing threshold, if it is determined whether the current accumulated number of valve closing times is greater than the preset valve closing threshold, the method further includes:
and determining that the second parameter is 0 and the zero point correction value is the current actual closing position.
Optionally, in the method for controlling a gas proportional valve of a natural gas engine, determining whether the gas proportional valve currently meets a self-learning condition of a zero position includes:
when the engine enters a drag-down working condition, judging whether the pressure difference between an inlet and an outlet of the gas proportional valve is smaller than a preset pressure drop threshold value, the set opening of the gas proportional valve is smaller than a zero point set threshold value, and the current actual closing position is within the range of the zero point position threshold value.
The application second aspect discloses a natural gas engine gas proportional valve controlling means includes:
the first judgment unit is used for judging whether the gas proportional valve meets the self-learning condition of the zero position at present;
the accumulated valve closing frequency unit is used for determining the current valve closing accumulated frequency of the detected gas proportional valve if the judgment result of the first judgment unit is yes;
the second judgment unit is used for judging whether the current valve closing accumulated times is greater than a preset valve closing threshold value or not;
and the correcting unit is used for correcting the gas proportional valve when the current actual closing position of the gas proportional valve is detected to be within the threshold range of the zero position if the judgment result of the second judging unit is yes.
Optionally, in the natural gas engine gas proportional valve control device, the correction unit is configured to, when correcting the gas proportional valve, specifically:
judgment of yn-znWhether it is greater than a zero offset threshold;
if so, then z is determinedn＝zn-1+ D; if not, determining zn＝yn；
Determination of wn＝xn-zn；
Wherein D is a zero offset threshold; y isnThe second parameter is the second parameter when the valve is closed for the nth time; z is a radical ofnThe zero self-learning value is the zero self-learning value when the valve is closed for the nth time; z is a radical ofn-1The zero self-learning value is the zero self-learning value when the valve is closed for the (n-1) th time; w is anThe valve zero correction value is the valve zero correction value at the time of the nth valve closing.
Optionally, in the above natural gas engine gas proportional valve control device, further comprising:
and the fault unit is used for judging that the zero offset fault occurs in the gas proportional valve when the current actual closing position of the gas proportional valve is detected to be out of the zero position threshold range if the judgment result of the second judgment unit is yes.
Optionally, in the natural gas engine gas proportional valve control device, the first judging unit is configured to, when judging whether the gas proportional valve currently meets a zero position self-learning condition, specifically:
when the engine enters a drag-down working condition, judging whether the pressure difference between an inlet and an outlet of the gas proportional valve is smaller than a preset pressure drop threshold value, the set opening of the gas proportional valve is smaller than a zero point set threshold value, and the current actual closing position is within the range of the zero point position threshold value.
According to the technical scheme, the control method of the natural gas engine gas proportional valve comprises the following steps: judging whether the gas proportional valve meets the self-learning condition of the zero position at present; if yes, determining to detect the current valve closing accumulated times of the gas proportional valve; judging whether the current accumulated valve closing times are larger than a preset valve closing threshold value or not; if the current accumulated valve closing times are larger than a preset valve closing threshold, correcting the gas proportional valve when the current actual closing position of the gas proportional valve is detected to be within the zero position threshold range; therefore, the opening degree of the gas proportional valve can be corrected under the condition of zero offset, so that the gas proportional valve can still provide proper and correct gas supply flow, gas leakage and pipeline blockage are prevented, the problem of fault misinformation is reduced, and the gas proportional valve is more comprehensive and accurate compared with the existing control strategy.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic diagram of a gas ratio of a natural gas engine provided by an embodiment of the invention;
FIG. 2 is a flow chart of a control method for a gas proportional valve of a natural gas engine according to an embodiment of the invention;
FIG. 3 is a flow chart of another method for controlling a gas proportional valve of a natural gas engine according to an embodiment of the invention;
fig. 4 is a flow chart of another method for controlling a gas proportional valve of a natural gas engine according to an embodiment of the invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In this application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
The embodiment provides a control method for a natural gas engine fuel gas proportional valve, which is used for solving the problem that in the prior art, an electric control logic cannot carry out quick and effective monitoring control on the opening and closing of fuel gas of the natural gas proportional valve.
As shown in fig. 1, it shows a schematic structural diagram of a gas proportional valve of a natural gas engine. Wherein: 1 is a natural gas cylinder; 2 is a gas pipeline inlet pressure temperature sensor; 3 is an electromagnetic cut-off valve; 4 is a combination part of a position sensor and a pressure sensor; 5 is a proportional valve; 6 is a gas pipeline gas outlet pressure temperature sensor; 7 is a gas proportional valve; 8 is an engine; and 9 is an electronic control unit.
It should be noted that the schematic structure shown in fig. 1 does not represent an actual layout: fig. 1 is a schematic structural diagram of a gas proportional valve, which is not drawn according to a drawing scale or an actual arrangement situation, but is measured and fed back by a gas inlet and a gas outlet of the gas proportional valve and a plurality of distributed sensors. Wherein, the electromagnetic cut-off valve 3 is only used as a switch and can only be opened or closed, the closed position (zero point) is particularly used for the proportional valve 5, and the proportional valve 5 can be opened or closed according to a certain percentage.
The natural gas engine fuel gas proportional valve is composed of an electromagnetic cut-off valve 3, a combination part 4 of a proportional valve position sensor and a pressure sensor, proportional valves 5, 2 and 6 fuel gas inlet and outlet temperature and pressure sensors and the like. The gas enters the proportional valve 5 through the electromagnetic cut-off valve 3, the proportional valve 5 calculates the gas demand according to the monitoring data of the sensors 2, 4 and 6 and software logic, the gas demand is converted into the set opening of the proportional valve 5, and the valve is opened to the correct opening according to the set opening command, so that the reasonable and proper gas is ensured to enter the engine to be ignited.
In the embodiment, whether the gas proportional valve meets the self-learning condition of the zero position at present is judged; if yes, determining to detect the current valve closing accumulated times of the gas proportional valve; judging whether the current accumulated valve closing times are larger than a preset valve closing threshold value or not; if the current accumulated valve closing times are larger than a preset valve closing threshold, correcting the gas proportional valve when the current actual closing position of the gas proportional valve is detected to be within the zero position threshold range; therefore, the opening degree of the gas proportional valve can be corrected under the condition of zero offset, so that the gas proportional valve can still provide proper and correct gas supply flow, gas leakage and pipeline blockage are prevented, the problem of fault misinformation is reduced, and the gas proportional valve is more comprehensive and accurate compared with the existing control strategy.
Referring to fig. 2, the control method of the gas proportional valve of the natural gas engine comprises the following steps:
s101, judging whether the gas proportional valve meets the self-learning condition of the zero position at present.
That is, the zero point position self-learning condition may be preset, so that when the zero point position self-learning is mainly performed, the corresponding zero point position self-learning strategy is executed.
Specifically, the zero point position self-learning strategy may include the subsequent steps S102-S104. The details are not repeated here, and refer to the following description for details.
If the gas proportional valve currently satisfies the zero point position self-learning condition, step S102 is executed.
S102, determining the current valve closing accumulated times of the detected gas proportional valve.
It should be noted that n is taken as the current accumulated valve closing times; its initial value is 0; when the gas proportional valve is detected to be closed once, n is equal to n + 1; that is, n is accumulated by 1. Therefore, the current valve closing accumulated times can be determined by acquiring the current value of n.
S103, judging whether the current valve closing accumulated times are larger than a preset valve closing threshold value.
If the current accumulated valve closing times is greater than the preset valve closing threshold, step S104 is executed.
And S104, when the current actual closing position of the gas proportional valve is detected to be within the zero position threshold range, correcting the gas proportional valve.
Namely, an electric control strategy is provided for the closed position of the gas proportional valve, namely the zero position; the electric control strategy can ensure that the zero position is accurate when the gas proportional valve is closed, even if the zero point of the closed position slightly deviates, the deviation of the closed position can be corrected through the electric control logic, and the opening degree of the gas proportional valve is consistent with the opening degree required by a transmitted instruction, for example, 50% opening is realized, 0% opening is realized when the gas proportional valve is closed, and 100% opening is realized when the gas proportional valve is fully opened.
The purpose of the gas proportional valve is mainly to improve the accuracy of the gas proportional valve from opening to closing and from closing to opening. The actual opening is not detected by the computer board according to the sensor, if no correction is made, the sensor detects that the proportional valve 5 is opened by 50%, the engine computer board, namely the electronic control unit, determines that the proportional valve is opened by 50%, and the actual sensor is deviated by 5%. The proportional valve 5 is actually opened by only 45%, which affects the actual gas supply, which becomes less and affects the operation of the engine.
In this embodiment, only if the closing position of the gas proportional valve itself is within a reasonable range, the structure of the gas proportional valve itself can be ensured to have no hardware fault, correct gas quantity can be provided, and gas leakage is prevented at the same time.
In practical application, judging whether the gas proportional valve meets the self-learning condition of the zero position at present comprises the following steps:
when the engine enters a drag-down working condition, judging whether the pressure difference between an inlet and an outlet of the gas proportional valve is smaller than a preset pressure drop threshold value, the set opening of the gas proportional valve is smaller than a zero point set threshold value, and the current actual closing position is within the zero point position threshold value range.
The above judgment may be divided into three judgments, which are: first judgment: judging whether the pressure difference between an inlet and an outlet of the fuel gas proportional valve is smaller than a preset pressure drop threshold value or not; second judgment: judging whether the set opening of the gas proportional valve is smaller than a zero-point set threshold value or not; and (3) third judgment: and judging whether the current actual closing position is within the zero position threshold range.
The sequence of the three judgments may be arbitrary, and is not specifically limited herein, and all of them are within the protection scope of the present application, depending on the actual situation.
As shown in fig. 4, the sequence is shown in one of the sequences, and the other sequences are not described herein and are within the scope of the present application.
That is, the self-learning of the zero-entering position of the gas proportional valve needs to satisfy the following conditions:
firstly, the engine enters a back-dragging working condition and the gas supply is cut off.
Wherein, drag operating mode gas to cut off: the engine is in a reverse dragging working condition, namely an oil cut-off working condition only under the condition that the rotating speed of the engine does not have an accelerator, and the engine does not spray gas at the moment, so that the gas proportional valve is naturally cut off and returns to a closing position, namely a zero position.
And secondly, the difference value delta Pn of the gas pressure at the inlet and the outlet of the gas proportional valve is smaller than a set pressure drop threshold Pn.
A gas proportional valve which can be fully opened from closed to 100%; based on the mechanical structure of the gas proportional valve, the gas pressure of the gas inlet and the gas outlet has a certain pressure difference, namely pressure drop; referring to fig. 1, when the gas proportional valve is closed, that is, the electromagnetic cut-off valve 3 is closed (the electromagnetic cut-off valve 3 only has two forms of opening and closing), the proportional valve 5 is also completely closed and returns to the zero position, only a little gas remains in the body, the inlet pressure is measured by the combination part 4 of the proportional valve position sensor and the pressure sensor, the outlet pressure is measured by the gas inlet and outlet temperature and pressure sensor 6, the difference value of the inlet and outlet pressures is a value close to zero, so that a smaller threshold value of the gas pressure drop is set, when the inlet and outlet pressure difference is smaller than the threshold value of the gas pressure drop, the gas proportional valve is considered to be completely closed and return to the zero, and then the control logic of self-learning of the zero position can be entered. When the pressure difference between the inlet and the outlet is larger than the threshold value of the gas pressure drop, the proportional valve 5 is not considered to be completely closed, and the gas flows in the middle, so that the next step cannot be carried out.
And thirdly, when the electric control unit sends a closing command of the gas proportional valve, after the set time is delayed, the set opening value un of the gas proportional valve is smaller than the set zero point set threshold value C, and the gas proportional valve is confirmed to receive the closing command and be closed.
It should be noted that, the operation mode of the proportional valve 5 is to give a set command to close, at this time, the set opening is 0, when the proportional valve 5 is fully closed, the closing is considered to be 0%, and actually there may be a slight difference of a few percent, even a few tenths of a percent; therefore, a set zero threshold C is defined, which is the maximum threshold that can be tolerated, and when the set command of the proportional valve 5 is smaller than the zero threshold C, it represents that the closing operation of the proportional valve 5 is started; it should be noted that the command is sent here, and not executed, and the execution is performed in the next step. When the set command of the proportional valve 5 is greater than the zero point threshold C, the closing command of the proportional valve 5 has not yet started to be sent.
Fourthly, when the closing command received by the gas proportional valve is delayed for a set time, the actual opening value x of the gas proportional valve monitored by the position sensornAnd when the value is smaller than the set zero position threshold value A of the gas proportional valve, the gas proportional valve is confirmed to be closed.
Zero threshold a: the proportional valve 5 is commanded to close in the previous step, starts to execute the command, the proportional valve 5 starts to close, and then the combination of the position sensor and the pressure sensor 4 can detect whether the proportional valve 5 is completely closed. In fact, the sensor has errors, so that there is a slight difference of about a few percent, even a few tenths of a percent, after the combination 4 of the position sensor and the pressure sensor detects that the gas proportional valve is closed, but the actual proportional valve 5 is completely closed, so that a zero threshold value a is given, when the actually measured position of the combination 4 of the position sensor and the pressure sensor is smaller than the given zero threshold value a, the proportional valve 5 is considered to be really closed, otherwise, the proportional valve 5 is considered not to be closed. The proportional valve 5 is not closed, and there is a possibility that the operation is not performed, or the proportional valve 5 itself is damaged and cannot be closed, and the next action cannot be performed.
It should be noted that, through the above- (c), (c) and (c), (c) the gas proportional valve is considered to be completely closed, and the gas proportional valve is ensured to be closed. The correction starts with respect to the difference of a few tenths of a percent that occurs in the above description.
In practical application, as shown in fig. 3, the correction of the fuel gas proportional valve in step S104 includes:
s201, judging yn-znWhether greater than a zero offset threshold.
If yes, go to step S202.
S202, determining zn＝zn-1+D。
If not, go to step S203.
S203, determining zn＝yn。
Step S204 is performed after both steps S202 and S203.
S204, determining wn＝xn-zn。
Wherein D is a zero offset threshold; y isnThe second parameter is the second parameter when the valve is closed for the nth time; z is a radical ofnThe zero self-learning value is the zero self-learning value when the valve is closed for the nth time; z is a radical ofn-1The zero self-learning value is the zero self-learning value when the valve is closed for the (n-1) th time; w is anFor valve zero point repair at the time of n-th valve closingA positive value.
When the engine 8 is stopped, the electromagnetic cut-off valve 3 directly cuts off the gas supply to prevent gas leakage; when the engine 8 is running, the gas proportional valve will return to the closed position only under the condition that the air supply is cut off under the condition of the back-dragging working condition, and the closed position of the gas proportional valve is the zero position of the gas proportional valve.
Assuming that the variable of the closing times of the gas proportional valve in each engine starting cycle is n, wherein n is 0, 1, 2, 3, … …; monitoring the minimum closing time threshold of the gas proportional valve to be B; the difference value of the gas pressure at the inlet and the outlet of the gas proportional valve is delta P, and the pressure drop threshold value is P; the set opening of the gas proportional valve is u, and the zero point set threshold value is C; the position sensor monitors that the actual opening variable of the gas proportional valve is x, and the zero position threshold value is A; storing a variable of each actually measured zero value as y, wherein the initial y is 0; the variable of the zero self-learning is z, and the initial z is 0; the zero point position correction value variable of the gas proportional valve is w.
Zero self-learning mathematical calculation: when the proportional valve 5 is closed, the connector 4 of the position sensor and the pressure sensor measures that the closing opening of the proportional valve 5 is x, and the closing opening x is stored in a register of a computer board at the moment, so that the proportional valve is convenient to use later, and therefore, y is x and is used for storing in the register. x also needs to measure the opening at the time of closing the next time the proportional valve 5 is closed. z represents the value requiring the zero point self-learning correction and w represents the position of the proportional valve 5 after the zero point correction. For example, when the proportional valve 5 is closed, x is 5%, w is x-z is 0%, and w is used by the control unit in the computer board to know and control how large the proportional valve 5 is actually opened, that is, x is offset by 5% and subtracted, and when the proportional valve 5 is opened x is 50%, w becomes 45%, so that the computer board knows that the proportional valve 5 is actually opened by 45%, and the actual measurement is not reliable.
Specifically, when the zero point self-learning correction is entered for the first time, a correction value z is 0, when the sizes of y and z satisfy that y-z is larger than D (that is, x-z is larger than D measured this time), it is unknown that y-z is equal to several times of D, a zero point offset maximum threshold value is assigned to z first, so that z is 0+ D, the zero point position after the correction is changed to w-z is x-D, when the next time of judgment is entered, x measured for the new time is assigned to y, if y-z is still larger than D (at this time, z is D), D is assigned to z, z is D + D, and the zero point position after the correction is w-x-z is x-2D … …; if y-z is smaller than D once, the degree of zero point position shift is considered to be within the acceptable range, and at this time, it is only necessary to subtract x next time without performing correction a plurality of times.
In practical application, the second parameter is the current actual closing position of the gas proportional valve.
That is, yn＝xn，xnThe current actual closed position detected the nth time.
In practical application, after judging whether the current accumulated valve closing times is greater than a preset valve closing threshold, the method further includes:
and when the current actual closing position of the gas proportional valve is detected to be out of the zero position threshold range, judging that the zero offset fault occurs in the gas proportional valve.
If the valve closing position x is outside the zero position threshold range A, then the zero offset fault is reported directly, i.e., when n > B, xnAnd if the voltage is more than A, reporting a zero offset fault.
That is, the current actual closing position cannot be restored to the zero point position by the correction, and an alarm needs to be given here, and the correction is performed manually.
In practical application, after determining whether the current accumulated number of valve closing times is greater than a preset valve closing threshold, if determining whether the current accumulated number of valve closing times is greater than the preset valve closing threshold, the method further includes:
it is determined that the second parameter is 0 and the zero point correction value is the current actual closed position.
Specifically, as shown in fig. 4, a zero point self-learning function of the valve closing position is entered, and the zero point self-learning method is as follows:
firstly, when the valve closing is detected for the nth time, judging whether n is smaller than a valve zero-returning position minimum time threshold B or not for preventing false alarm, and if n is smaller than the valve zero-returning position minimum time threshold B, performing zero offset fault judgment and zero self-learning functions.
Specifically, when n is less than or equal to B, yn＝xn，zn＝0，wn＝xnZero offset fault is not diagnosed, and zero self-learning is not started.
It should be noted that, the vehicle is powered on by inserting the key, started, the engine is operated, stopped, and the key is powered off, which are considered as a cycle. In one cycle, as long as oil is cut off, the proportional valve 5 is closed certainly, so the computer board of the engine, namely the electronic control unit, records once, and in the next cycle, the closing times of the proportional valve are recorded from 0 again. Assuming that the number n of times of closing the proportional valve 5, the minimum number B, B of closing is to power on the key, when the engine is started, the previous times of closing the proportional valve 5 may be due to the fact that each electrical element is just powered on, and operations such as self-detection are required, which affects the measurement accuracy of each sensor, and may cause detection errors. When the closing times of the proportional valve are more than B, the system is considered to be completely operated normally, and zero self-learning can be formally started. Zero self-learning learns in every cycle, but the last learned value of the previous cycle is stored in each cycle, so that the learning is not started from zero when the condition is met for the next time.
And secondly, when the valve closing is detected for the nth time, and n is greater than the zero position minimum time threshold value B, if the valve closing position x is out of the zero position threshold value range A, directly reporting a zero offset fault.
Specifically, when n > B, xnAnd if the voltage is more than A, reporting a zero offset fault.
As can be seen from the above description, having sent a command to close the proportional valve 5, the proportional valve 5 starts executing the closing command, and when the measured position of the combination 4 of position sensor and pressure sensor is greater than a given zero threshold a, the proportional valve is considered not to have closed. If the value is always larger than A, the proportional valve 5 is considered to be damaged or not closed, and is blocked, a fault is reported, and the next action cannot be carried out at the instrument panel of the driver cab.
And thirdly, when the valve is detected to be closed for the nth time, and n is greater than the threshold value B of the minimum number of times of the zero position, if the valve closing position x is within the range A of the second parameter threshold value, performing a zero self-learning function.
Specifically, when n > B and xnWhen A is less than or equal to Yn＝xnIf y isn-zn＞D，zn＝zn-1+ D; otherwise, zn＝yn. Valve zero correction value of wn＝xn-zn。
Through zero point self-learning, the opening degree of the valve is corrected, and the valve can still provide proper and correct gas supply flow under the condition of zero point offset.
When the proportional valve 5 is closed, the position x is measurednIf x isnAssigned value to ynAfter subtracting znIf the zero offset is larger than the zero offset threshold value D, the zero offset is not within the acceptable range, and a series of corrections are needed to gradually reduce the actual measurement position. If y isn-znIf the zero point position is less than the threshold value D, the zero point position is considered to be slightly shifted, but the zero point position is not greatly influenced, so that the x is corrected for the next time without being corrected for many timesnMinus znAnd (4) finishing.
It should be noted that, the variable correspondence relationship is: the gas pipeline inlet pressure temperature sensor 2 can only detect the gas pressure and temperature in front of the electromagnetic cut-off valve 3; a combination of position sensor and pressure sensor 4, which can measure the actual opening of the proportional valve 5, i.e. xnSubscript n is the closing times of the proportional valve mentioned above, and n-1 is the closing time of the proportional valve last time, which is not described herein any more and is within the protection scope of the present application; meanwhile, the combination part 4 of the position sensor and the pressure sensor can also measure the gas pressure of the gas inlet of the proportional valve 5. The gas pipeline gas outlet pressure temperature sensor 6 can measure the gas outlet gas pressure of the proportional valve 5. All of the threshold values A, B, C, D and the like are set values written on the computer board based on a certain experimental result or experience, and are values that do not change as long as they are determined. Specific values are not repeated here, and are determined according to actual conditions and are all within the protection scope of the application.
In the embodiment, the gas proportional valve is normally opened and safely closed by using the gas open-close and zero self-learning electric control logic control of the valve front and rear pressure and temperature sensors, the proportional valve position sensor, the electromagnetic cut-off valve and the like on the gas proportional valve, so that gas leakage and pipeline blockage are prevented, the false alarm of related faults is reduced, and the control strategy is more comprehensive and accurate compared with the existing control strategy.
The application further provides a gas proportional valve control device of the natural gas engine.
The gas proportional valve control device of the natural gas engine comprises:
and the first judgment unit is used for judging whether the gas proportional valve meets the self-learning condition of the zero position at present.
And the accumulated valve closing frequency unit is used for determining the current valve closing accumulated frequency of the detected gas proportional valve if the judgment result of the first judgment unit is positive.
And the second judgment unit is used for judging whether the current valve closing accumulated times is greater than a preset valve closing threshold value.
And the correcting unit is used for correcting the gas proportional valve when the current actual closing position of the gas proportional valve is detected to be within the threshold range of the zero position if the judgment result of the second judging unit is yes.
In practical application, the correction unit is used for correcting the gas proportional valve, and is specifically used for:
judgment of yn-znWhether greater than a zero offset threshold.
If so, then z is determinedn＝zn-1+ D; if not, determining zn＝yn。
Determination of wn＝xn-zn。
Wherein D is a zero offset threshold; y isnThe second parameter is the second parameter when the valve is closed for the nth time; z is a radical ofnThe zero self-learning value is the zero self-learning value when the valve is closed for the nth time; z is a radical ofn-1The zero self-learning value is the zero self-learning value when the valve is closed for the (n-1) th time; w is anThe valve zero correction value is the valve zero correction value at the time of the nth valve closing.
In practical application, the method further comprises the following steps:
and the fault unit is used for judging that the zero offset fault occurs in the gas proportional valve when the current actual closing position of the gas proportional valve is detected to be out of the zero position threshold range if the judgment result of the second judgment unit is yes.
In practical application, when the first judging unit is used for judging whether the gas proportional valve currently meets the zero position self-learning condition, the first judging unit is specifically used for:
when the engine enters a drag-down working condition, judging whether the pressure difference between an inlet and an outlet of the gas proportional valve is smaller than a preset pressure drop threshold value, the set opening of the gas proportional valve is smaller than a zero point set threshold value, and the current actual closing position is within the range of the zero point position threshold value.
The working process and principle of each unit are referred to the gas proportional valve control method of the natural gas engine provided by the above embodiment for details, which are not described herein again and are all within the protection scope of the present application.
In the embodiment, the first judging unit judges whether the gas proportional valve meets the zero position self-learning condition currently; if the judgment result of the first judgment unit is yes, the accumulated valve closing times unit determines the current valve closing accumulated times of the detected gas proportional valve; the second judgment unit judges whether the current accumulated valve closing times are larger than a preset valve closing threshold value or not; if the judgment result of the second judgment unit is yes, the correction unit corrects the gas proportional valve when detecting that the current actual closing position of the gas proportional valve is within the zero position threshold range; therefore, the opening degree of the gas proportional valve can be corrected under the condition of zero offset, so that the gas proportional valve can still provide proper and correct gas supply flow, gas leakage and pipeline blockage are prevented, the problem of fault misinformation is reduced, and the gas proportional valve is more comprehensive and accurate compared with the existing control strategy.
Features described in the embodiments in the present specification may be replaced with or combined with each other, and the same and similar portions among the embodiments may be referred to each other, and each embodiment is described with emphasis on differences from other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.
Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A control method for a gas proportional valve of a natural gas engine is characterized by comprising the following steps:
judging whether the gas proportional valve meets the self-learning condition of the zero position at present;
if yes, determining to detect the current valve closing accumulated times of the gas proportional valve;
judging whether the current accumulated valve closing times are larger than a preset valve closing threshold value or not;
and if the current accumulated valve closing times are larger than the preset valve closing threshold, correcting the gas proportional valve when the current actual closing position of the gas proportional valve is detected to be within the zero position threshold range.
2. The natural gas engine gas proportional valve control method of claim 1, wherein modifying the gas proportional valve comprises:
judgment of yn-znWhether it is greater than a zero offset threshold;
if so, then z is determinedn＝zn-1+ D; if not, determining zn＝yn；
Determination of wn＝xn-zn；
Wherein D is a zero offset threshold; y isnThe second parameter is the second parameter when the valve is closed for the nth time; z is a radical ofnThe zero self-learning value is the zero self-learning value when the valve is closed for the nth time; z is a radical ofn-1The zero self-learning value is the zero self-learning value when the valve is closed for the (n-1) th time; w is anThe valve zero correction value is the valve zero correction value when the valve is closed for the nth time; x is the number ofnIs the current actual closed position.
3. The natural gas engine gas proportional valve control method of claim 2, wherein the second parameter takes a current actual closed position of the gas proportional valve.
4. The control method of the gas proportional valve of the natural gas engine according to claim 1, wherein after determining whether the current accumulated times of valve closing is greater than a preset valve closing threshold, if the current accumulated times of valve closing is greater than the preset valve closing threshold, the method further comprises:
and when the current actual closing position of the gas proportional valve is detected to be out of the zero position threshold range, judging that the gas proportional valve has zero offset fault.
5. The control method of the gas proportional valve of the natural gas engine according to claim 1, wherein after determining whether the current accumulated times of valve closing is greater than a preset valve closing threshold, if it is determined whether the current accumulated times of valve closing is greater than the preset valve closing threshold, the method further comprises:
and determining that the second parameter is 0 and the zero point correction value is the current actual closing position.
6. The natural gas engine gas proportional valve control method according to any one of claims 1 to 5, wherein judging whether the gas proportional valve currently satisfies a zero position self-learning condition comprises:
when the engine enters a drag-down working condition, judging whether the pressure difference between an inlet and an outlet of the gas proportional valve is smaller than a preset pressure drop threshold value, the set opening of the gas proportional valve is smaller than a zero point set threshold value, and the current actual closing position is within the range of the zero point position threshold value.
7. A natural gas engine gas proportional valve control device is characterized by comprising:
the first judgment unit is used for judging whether the gas proportional valve meets the self-learning condition of the zero position at present;
the accumulated valve closing frequency unit is used for determining the current valve closing accumulated frequency of the detected gas proportional valve if the judgment result of the first judgment unit is yes;
the second judgment unit is used for judging whether the current valve closing accumulated times is greater than a preset valve closing threshold value or not;
and the correcting unit is used for correcting the gas proportional valve when the current actual closing position of the gas proportional valve is detected to be within the threshold range of the zero position if the judgment result of the second judging unit is yes.
8. The natural gas engine gas proportional valve control device according to claim 7, wherein the correction unit is configured to, when correcting the gas proportional valve, specifically:
judgment of yn-znWhether it is greater than a zero offset threshold;
if so, then z is determinedn＝zn-1+ D; if not, determining zn＝yn；
Determination of wn＝xn-zn；
Wherein D is a zero offset threshold; y isnThe second parameter is the second parameter when the valve is closed for the nth time; z is a radical ofnThe zero self-learning value is the zero self-learning value when the valve is closed for the nth time; z is a radical ofn-1The zero self-learning value is the zero self-learning value when the valve is closed for the (n-1) th time; w is anThe valve zero correction value is the valve zero correction value at the time of the nth valve closing.
9. The natural gas engine gas proportional valve control apparatus according to claim 7, further comprising:
and the fault unit is used for judging that the zero offset fault occurs in the gas proportional valve when the current actual closing position of the gas proportional valve is detected to be out of the zero position threshold range if the judgment result of the second judgment unit is yes.
10. The natural gas engine gas proportional valve control device according to any one of claims 7 to 9, wherein the first determination unit is configured to, when determining whether the gas proportional valve currently satisfies the zero point position self-learning condition, specifically:
when the engine enters a drag-down working condition, judging whether the pressure difference between an inlet and an outlet of the gas proportional valve is smaller than a preset pressure drop threshold value, the set opening of the gas proportional valve is smaller than a zero point set threshold value, and the current actual closing position is within the range of the zero point position threshold value.
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