CN114233502B - A natural gas engine gas proportional valve control method and device - Google Patents

Abstract

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

Description

A natural gas engine gas proportional valve control method and device

Technical field

The present invention belongs to the technical field of gas proportional valve control, and more specifically, relates to a method and device for controlling a gas proportional valve of a natural gas engine.

Background technique

The existing gas proportional valve of a natural gas engine cannot perform reasonable electronic control logic control of the gas opening and closing positions, which can easily lead to problems such as inaccurate gas supply flow control and lax sealing of the gas proportional valve closing position.

Under complex application environment conditions, the gas injection valve requires excessive pipeline pressure, which can easily lead to pipeline leakage, and the gas nozzle is easily blocked by impurities, resulting in a high failure rate of gas injection valves and their pipelines in the market; and, existing electric power supplies The control logic cannot quickly and effectively monitor and control the gas opening and closing of the gas proportional valve.

Contents of the invention

In view of this, the object of the present invention is to provide a method and device for controlling a gas proportional valve of a natural gas engine, which can correct the opening of the gas proportional valve when the gas proportional valve deviates from the zero point, so that it can still provide appropriate Correct gas supply flow prevents gas leakage and pipeline blockage, and reduces false alarms.

The first aspect of this application discloses a method for controlling a gas proportional valve of a natural gas engine, including:

Determine whether the gas proportional valve currently meets the zero position self-learning conditions;

If so, determine the current cumulative number of valve closing times of the gas proportional valve detected;

Determine whether the current cumulative number of valve closing times is greater than a preset valve closing threshold;

If the current cumulative number of valve closing times is greater than the preset valve closing threshold, when it is detected that the current actual closing position of the gas proportional valve is within the zero position threshold range, the gas proportional valve is corrected.

Optionally, in the above natural gas engine gas proportional valve control method, the gas proportional valve is modified, including:

Determine whether y _n -z _n is greater than the zero offset threshold;

If yes, then determine z _n =z _n-1 +D; if not, then determine z _n =y _n ;

Determine w _n =x _n- z _n ;

Among them, D is the zero offset threshold; y _n is the second parameter when closing the valve for the nth time; z _n is the zero self-learning value when closing the valve for the nth time; z _n-1 is the n-1th valve closing The zero-point self-learning value at the time; w _n is the valve zero-point correction value when the valve is closed for the nth time.

Optionally, in the above natural gas engine gas proportional valve control method, the second parameter is the current actual closed position of the gas proportional valve.

Optionally, in the above natural gas engine gas proportional valve control method, after judging whether the current cumulative number of valve closing times is greater than the preset valve closing threshold, if the current cumulative number of valve closing times is greater than the preset valve closing threshold , then it also includes:

When it is detected that the current actual closed position of the gas proportional valve is outside the zero position threshold range, it is determined that a zero offset fault occurs in the gas proportional valve.

Optionally, in the above natural gas engine gas proportional valve control method, after determining whether the current cumulative number of valve closing times is greater than the preset valve closing threshold, if it is determined whether the current cumulative number of valve closing times is greater than the preset valve closing threshold , then it also includes:

It is determined that the second parameter is 0, and the zero point correction value is the current actual closed position.

Optionally, in the above natural gas engine gas proportional valve control method, determining whether the gas proportional valve currently meets the zero position self-learning conditions includes:

When the engine enters the reverse towing condition, it is determined whether the inlet and outlet pressure difference of the gas proportional valve is less than the preset pressure drop threshold, the set opening of the gas proportional valve is less than the zero setting threshold, and, The current actual closing position is within the zero position threshold range.

The second aspect of this application discloses a natural gas engine gas proportional valve control device, which includes:

The first judgment unit is used to judge whether the gas proportional valve currently meets the zero position self-learning condition;

A cumulative number of valve closing times unit, configured to determine the current cumulative number of valve closing times of the gas proportional valve detected if the judgment result of the first judgment unit is yes;

The second judgment unit is used to judge whether the current cumulative number of valve closings is greater than the preset valve closing threshold;

A correction unit configured to, if the judgment result of the second judgment unit is yes, correct the gas proportional valve when it is detected that the current actual closing position of the gas proportional valve is within the zero position threshold range.

Optionally, in the above natural gas engine gas proportional valve control device, when the correction unit is used to correct the gas proportional valve, it is specifically used for:

Determine whether y _n -z _n is greater than the zero offset threshold;

If yes, then determine z _n =z _n-1 +D; if not, then determine z _n =y _n ;

Determine w _n =x _n- z _n ;

Among them, D is the zero offset threshold; y _n is the second parameter when closing the valve for the nth time; z _n is the zero self-learning value when closing the valve for the nth time; z _n-1 is the n-1th valve closing The zero-point self-learning value at the time; w _n is the valve zero-point correction value when the valve is closed for the nth time.

Optionally, the above gas proportional valve control device for natural gas engines also includes:

A fault unit configured to determine that a zero point occurs in the gas proportional valve when it is detected that the current actual closing position of the gas proportional valve is outside the zero position threshold range if the judgment result of the second judgment unit is yes. Offset failure.

Optionally, in the above-mentioned natural gas engine gas proportional valve control device, the first judgment unit is used to judge whether the gas proportional valve currently meets the zero-point position self-learning condition, specifically for:

When the engine enters the reverse towing condition, it is determined whether the inlet and outlet pressure difference of the gas proportional valve is less than the preset pressure drop threshold, the set opening of the gas proportional valve is less than the zero setting threshold, and, The current actual closing position is within the zero position threshold range.

As can be seen from the above technical solution, the present invention provides a method for controlling a gas proportional valve of a natural gas engine, which includes: determining whether the gas proportional valve currently meets the zero position self-learning condition; if so, determining the current accumulated number of valve closing times of the detected gas proportional valve. ; Determine whether the current cumulative number of valve closing times is greater than the preset valve closing threshold; if the current cumulative number of valve closing times is greater than the preset valve closing threshold, when it is detected that the current actual closing position of the gas proportional valve is within the zero position threshold range, Correct the gas proportional valve; so that when the gas proportional valve is offset from zero, the opening of the gas proportional valve can be corrected so that it can still provide a suitable and correct gas supply flow, prevent gas leakage and pipeline blockage, and reduce failures The problem of false positives is more comprehensive and accurate than the existing control strategy.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are: For some embodiments of the present invention, those of ordinary skill in the art can also obtain other drawings based on these drawings without exerting creative efforts.

Figure 1 is a schematic diagram of the gas ratio of a natural gas engine provided by an embodiment of the present invention;

Figure 2 is a flow chart of a natural gas engine gas proportional valve control method provided by an embodiment of the present invention;

Figure 3 is a flow chart of another natural gas engine gas proportional valve control method provided by an embodiment of the present invention;

Figure 4 is a flow chart of another method for controlling a gas proportional valve of a natural gas engine provided by an embodiment of the present invention.

Detailed ways

In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

In this application, the terms "comprises," "comprises," or any other variation thereof are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements not only includes those elements, but also includes none. Other elements expressly listed, or elements inherent to such process, method, article or equipment. Without further limitation, an element defined by the statement "comprises a..." does not exclude the presence of additional identical elements in a process, method, article, or apparatus that includes the stated element.

This embodiment provides a method for controlling a gas proportional valve of a natural gas engine, which is used to solve the problem in the existing technology that electronic control logic cannot quickly and effectively monitor and control the opening and closing of the gas proportional valve.

As shown in Figure 1, it shows a schematic structural diagram of the gas proportional valve of a natural gas engine. Among them: 1 is a natural gas cylinder; 2 is a gas pipeline inlet pressure and temperature sensor; 3 is an electromagnetic shut-off valve; 4 is a combination of position sensor and pressure sensor; 5 is a proportional valve; 6 is a gas pipeline outlet pressure and temperature sensor. ; 7 is the gas proportional valve; 8 is the engine; 9 is the electronic control unit.

It should be noted that the structural schematic diagram shown in Figure 1 does not represent the actual layout: Figure 1 is a structural schematic diagram of the gas proportional valve. It is not drawn according to the drawing scale or actual layout. It is simply a diagram of the gas inlet of the gas proportional valve. and gas outlets, as well as by distributing several sensors for measurement and feedback. Among them, the electromagnetic cut-off valve 3 is just a switch, which can only be opened or closed. The closed position (zero point) refers specifically to the proportional valve 5, which can be opened and closed according to a certain percentage.

The gas proportional valve of a natural gas engine is composed of an electromagnetic cut-off valve 3, a combination of a proportional valve position sensor and a pressure sensor 4, a proportional valve 5, and gas inlet and outlet temperature and pressure sensors 2 and 6. The gas enters the proportional valve 5 through the electromagnetic cut-off valve 3. The proportional valve 5 calculates the gas demand based on the monitoring data of sensors 2, 4, and 6 and software logic, and converts it into the set opening of the proportional valve 5. The valve opens according to the set opening command. The correct opening ensures that a reasonable and appropriate amount of gas enters the engine for ignition.

In this embodiment, it is determined whether the gas proportional valve currently meets the zero position self-learning condition; if so, it is determined that the current cumulative number of valve closing times of the gas proportional valve is detected; and it is determined whether the current cumulative number of valve closing times is greater than the preset valve closing threshold. ; If the current cumulative number of valve closing times is greater than the preset valve closing threshold, then when it is detected that the current actual closing position of the gas proportional valve is within the zero position threshold range, the gas proportional valve will be corrected; thus the gas proportional valve will deviate at the zero point. In this case, the opening of the gas proportional valve can be corrected so that it can still provide a suitable and correct gas supply flow, prevent gas leakage and pipeline blockage, and reduce the problem of false alarms. Compared with the existing control strategy, it is more comprehensive. accurate.

Referring to Figure 2, the natural gas engine gas proportional valve control method includes:

S101. Determine whether the gas proportional valve currently meets the zero position self-learning conditions.

That is to say, the zero-point position self-learning conditions can be set in advance, so that the corresponding zero-point position self-learning strategy can be executed when the zero-point position self-learning is mainly performed.

Specifically, the zero-point position self-learning strategy may include subsequent steps S102-S104 and other steps. I won’t go into details here, please refer to the following description for details.

It should be noted that if the gas proportional valve currently meets the zero position self-learning condition, step S102 is executed.

S102. Determine the current accumulated number of valve closing times of the detected gas proportional valve.

It should be noted that n is the current cumulative number of valve closings; its initial value is 0; every time the gas proportional valve is detected to be closed, n = n + 1; that is, n is accumulated by 1. Therefore, the current cumulative number of valve closing times can be determined by obtaining the current value of n.

S103. Determine whether the current cumulative number of valve closing times is greater than the preset valve closing threshold.

If the current cumulative number of valve closing times is greater than the preset valve closing threshold, step S104 is executed.

S104. When it is detected that the current actual closing position of the gas proportional valve is within the zero position threshold range, correct the gas proportional valve.

In other words, an electronic control strategy is provided for the closed position of the gas proportional valve, which is the zero position; this electronic control strategy can make the zero position accurate when the gas proportional valve is closed, even if the zero point of the closed position is slightly offset, The offset of the above-mentioned closing position can also be corrected through electronic control logic to ensure that the opening of the gas proportional valve is consistent with the opening required by the issued instructions. For example, 50% open means 50% open, closed means 0%, and fully open means 100. %.

Its purpose is mainly to improve the accuracy of the gas proportional valve from opening to closing and from closing to opening. What is mentioned here is the actual opening, not what the computer board measures based on the sensor. If no correction is made, the sensor measures that the proportional valve 5 is open 50%, and the engine computer board, the electronic control unit, considers the proportional valve to be 50% open. , the actual sensor is offset by 5%. Then the proportional valve 5 is actually only opened 45%, which will affect the actual gas supply volume, and the gas supply volume will become less, affecting the operation of the engine.

In this embodiment, only when the closing position of the gas proportional valve itself is within a reasonable range, can it be ensured that the structure of the gas proportional valve itself has no hardware failure, can provide the correct amount of gas, and prevent gas leakage at the same time.

In practical applications, it is judged whether the gas proportional valve currently meets the zero position self-learning conditions, including:

When the engine enters the reverse towing condition, it is judged whether the inlet and outlet pressure difference of the gas proportional valve is less than the preset pressure drop threshold, the set opening of the gas proportional valve is less than the zero setting threshold, and the current actual closing position is at the zero position. within the threshold range.

It should be noted that the above judgments can be divided into three judgments, which are: the first judgment: judging whether the inlet and outlet pressure difference of the gas proportional valve is less than the preset pressure drop threshold; the second judgment: judging the setting of the gas proportional valve. Whether the opening is less than the zero setting threshold; third judgment: judging whether the current actual closing position is within the zero position threshold range.

The order of the three judgments can be arbitrary, and there is no specific limit here. It just depends on the actual situation, and they are all within the protection scope of this application.

As shown in FIG. 4 , it is shown in one of the sequences. The other sequences will not be described one by one here, and they are all within the protection scope of the present application.

In other words, the following conditions need to be met for the gas proportional valve to enter the zero position self-learning:

①. The engine enters reverse towing mode and cuts off the gas supply.

Among them, gas cutoff in reverse towing mode: The engine only has speed and no throttle, which is the reverse towing condition, also called fuel cutoff condition. At this time, the engine does not inject gas, so the gas proportional valve is naturally cut off and returns to the closed position, that is, zero point. Location.

②. The gas pressure difference ΔPn between the inlet and outlet of the gas proportional valve is less than the set pressure drop threshold Pn.

Gas proportional valve, which can be fully opened from closed to 100%; based on the mechanical structure of the gas proportional valve itself, there will be a certain pressure difference between the gas pressure at the gas inlet and the gas outlet, called pressure drop; combined with Figure 1, the gas proportional valve is closed When, that is, the electromagnetic cut-off valve 3 is closed (the electromagnetic cut-off valve 3 only has two modes: open and closed), the proportional valve 5 is also completely closed, returning to the zero position, and only a little bit of gas remains in the body. Through the proportional valve position sensor and The pressure sensor combination 4 measures the inlet pressure, and the gas inlet and outlet temperature and pressure sensor 6 measures the outlet pressure. The difference between the inlet and outlet pressures is a value that is approximately zero, so a smaller gas pressure drop threshold is set. When If the pressure difference between the inlet and outlet is less than the gas pressure drop threshold, it is considered that the gas proportional valve has been completely closed and returned to zero. At this time, the control logic of zero position self-learning can be entered. When the pressure difference between the inlet and outlet is greater than the gas pressure drop threshold, it is considered that the proportional valve 5 has not been completely closed, and there is still gas flowing in the middle, and the next step cannot be performed.

③. When the electronic control unit sends the gas proportional valve closing command, after delaying the set time, the set opening value un of the gas proportional valve is less than the set zero setting threshold C, confirming that the gas proportional valve has received the closing command and is closed.

It should be noted that the action mode of proportional valve 5 is to give a set command to close it. At this time, the opening is set to 0. When proportional valve 5 is fully closed, it is considered closed to 0%. In fact, There may be a slight difference of a few percent or even a few tenths of a percent; therefore, define a set zero threshold C, which is the maximum threshold that can be tolerated. When the setting command of the proportional valve 5 is less than the zero threshold C , which means that the proportional valve 5 is started to close; it should be noted that the command is sent here, not executed, and the execution is in the next step. When the setting command of the proportional valve 5 is greater than the zero threshold C, the closing command of the proportional valve 5 has not yet started to be sent.

④. When the gas proportional valve receives the closing command, after delaying the set time, the actual opening value x _n of the gas proportional valve monitored by the position sensor is less than the set zero position threshold A of the gas proportional valve, confirming that the gas proportional valve has been closed.

Zero point threshold A: The proportional valve 5 receives the closing command from the previous step and starts executing the command. The proportional valve 5 begins to close, and then the combination 4 of the position sensor and the pressure sensor can detect whether the proportional valve 5 is completely closed. In fact, the sensor also has errors, so after the combination 4 of the position sensor and the pressure sensor detects that the gas proportional valve is closed, there will be a slight difference of about a few percent, or even a few tenths of a percent, but the actual proportional valve 5 has been completely closed, so given a zero threshold A, when the measured position of the combination 4 of the position sensor and the pressure sensor is less than the given zero threshold A, it is considered that the proportional valve 5 is truly closed, otherwise it is considered that the proportional valve 5 has not yet closure. The proportional valve 5 is not closed. It is possible that the operation has not been completed, or the proportional valve 5 itself is damaged and cannot be closed, and the next step cannot be taken.

It should be noted that after the above ①②③④, it is considered that the gas proportional valve has been completely closed. Make sure that the gas proportional valve has been closed. So I started to make corrections for the few tenths of a percent difference in the above explanation.

In practical applications, as shown in Figure 3, the correction of the gas proportional valve involved in step S104 includes:

S201. Determine whether y _n -z _n is greater than the zero offset threshold.

If yes, step S202 is executed.

S202. Determine z _n =z _n-1 +D.

If not, execute step S203.

S203. Determine z _n =y _n .

Step S204 is executed after both steps S202 and S203.

S204. Determine w _n =x _n- z _n .

Among them, D is the zero offset threshold; y _n is the second parameter when closing the valve for the nth time; z _n is the zero self-learning value when closing the valve for the nth time; z _n-1 is the n-1th valve closing The zero-point self-learning value at the time; w _n is the valve zero-point correction value when the valve is closed for the nth time.

It should be noted that 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 when the gas supply is cut off during reverse towing conditions. The closed position of the gas proportional valve is when the gas proportional valve returns to the zero position.

Assume that in each engine starting cycle, the variable of the number of times the gas proportional valve is closed is n, n=0, 1, 2, 3,...; the minimum threshold for monitoring the number of times the gas proportional valve is closed is B; the gas pressure difference between the inlet and outlet of the gas proportional valve The value is △P, the pressure drop threshold is P; the set opening of the gas proportional valve is u, and the zero-point setting threshold is C; the position sensor detects that the actual opening variable of the gas proportional valve is x, and the zero-point position threshold is A; The variable that stores each measured zero point value is y, and the initial y=0; the variable for zero-point self-learning is z, and the initial z=0; the zero-point position correction value variable of the gas proportional valve is w.

Mathematical calculation of zero-point self-learning: When the proportional valve 5 is closed, the combination 4 of the position sensor and the pressure sensor measures the closed opening of the proportional valve 5 as x. At this time, the closed opening x is stored in the register of the computer board. It is convenient for later use, so y=x, y is used to store in the register. x also needs to measure the opening when the proportional valve 5 is closed next time. z represents the value that needs zero-point self-learning correction, and w represents the proportional valve 5 position after zero-point correction. For example, when the proportional valve 5 is closed, x=5%, w=x-z=0%, w is used by the control unit in the computer board to know and control how far the proportional valve 5 really opens, that is, x is offset. Subtracting the value of 5%, when the proportional valve 5 opens x = 50%, it becomes w = 45%, letting the computer board know that the proportional valve 5 is actually open 45%, and the actual measurement is not credible.

Specifically, when entering the zero-point self-learning correction for the first time, the correction value z=0. When the sizes of y and z satisfy that y-z is greater than D (that is, the actual measurement of this time is that x-z is greater than D), I don’t know how many times of D y-z is equal to. Just assign the maximum zero offset threshold to z first, let z=0+D. At this time, the zero point position after correction becomes w=x-z=x-D. When entering judgment next time, the newly measured x is assigned to y, if y-z is still greater than D (z=D at this time), continue to assign D to z, z=D+D, and the zero point position after trimming is w=x-z=x-2D...; if at a certain time, y-z If it is less than D, it is considered that the degree of zero point position deviation is within the acceptable range. At this time, there is no need to make multiple corrections. You only need to subtract the x value next time. Therefore, z=y, w=x-z=x-y.

In practical applications, the second parameter takes the current actual closing position of the gas proportional valve.

That is to say, y _n =x _n , x _n is the current actual closing position detected for the nth time.

In practical applications, after judging whether the current cumulative number of valve closing times is greater than the preset valve closing threshold, it also includes:

When it is detected that the current actual closing position of the gas proportional valve is outside the zero position threshold range, it is determined that the gas proportional valve has a zero offset fault.

If the valve closing position x is outside the zero position threshold range A, a zero offset fault is reported directly, that is, when n>B, x _n >A, a zero offset fault is reported.

In other words, the current actual closing position cannot be restored to the zero position through correction. An alarm is required here and manual correction is required.

In practical applications, after judging whether the current cumulative number of valve closing times is greater than the preset valve closing threshold, and then determining whether the current cumulative number of valve closing times is greater than the preset valve closing threshold, it also includes:

Determine the second parameter is 0, and the zero point correction value is the current actual closing position.

Specifically, as shown in Figure 4, enter the zero-point self-learning function at the closed position of the valve. The zero-point self-learning method is as follows:

① When it is detected that the valve is closed for the nth time, in order to prevent false alarms, it is necessary to determine whether n is less than the minimum number of times the valve returns to the zero position threshold B. If n is less than the minimum number of times the valve returns to the zero position threshold B, no zero offset fault judgment will be performed. And zero-point self-learning function.

Specifically, when n≤B, y _n =x _n , z _n =0, w _n =x _n , the zero-point offset fault is not diagnosed, and the zero-point self-learning is not enabled.

It should be noted that the vehicle is powered on with the key inserted, started, the engine is running, parked, and the key is powered off. The above is considered a cycle. In a cycle, as long as the oil is cut off, the proportional valve 5 must be closed, so the engine computer board, the electronic control unit, will record it once. In the next cycle, the number of times the proportional valve is closed will start recording again from 0. Assume that the proportional valve 5 is closed for the number of times n, and the minimum number of closures is B. The function of B is to power on the key. When the engine is started and running, the proportional valve 5 is closed for the first few times because the various electrical components have just been energized, and self-testing and other operations need to be performed. Affects the measurement accuracy of each sensor and may cause detection errors. When the number of times the proportional valve is closed is greater than B, it is considered that the system is fully operating normally and zero-point self-learning can be officially started. Zero-point self-learning will be learned in each cycle, but in each cycle, the last learned value of the previous cycle will be stored, so that the next time the conditions are met and then learned, there is no need to start from scratch.

②. When the valve closing is detected for the nth time, and n is greater than the minimum zero position threshold B, if the valve closing position x is outside the zero position threshold range A, a zero offset fault will be reported directly.

Specifically, when n>B, x _n >A, a zero offset fault is reported.

It can be seen from the above description that a command has been sent to close the proportional valve 5, and the proportional valve 5 begins to execute the closing command. When the measured position of the combination 4 of the position sensor and the pressure sensor is greater than the given zero threshold A, the proportional valve is considered not closed yet. If it is always greater than A, it is considered that the proportional valve 5 itself is broken, cannot be closed, or is stuck, and a fault will be reported. Now on the driver's cockpit dashboard, the next step cannot be taken.

③. When the valve closing is detected for the nth time, and n is greater than the minimum zero-point position threshold B, if the valve closing position x is within the second parameter threshold range A, the zero-point self-learning function will be performed.

Specifically, when n>B and x _n ≤A, y _n =x _n , if y _n -z _n >D, z _n =z _n -1+D; otherwise, z _n =y _n . The valve zero point correction value is w _n =x _n -z _n .

Through zero-point self-learning, the valve opening is corrected to ensure that the valve can still provide appropriate and correct gas supply flow even when the zero-point is offset.

It should _be noted that when _the proportional _valve 5 _is closed, the measured position A series of corrections gradually made the measured position smaller. If y _n -z _n is less than the threshold D, it is considered that although the zero point position is slightly offset, the impact is not too great. There is no need to make multiple corrections. Just subtract z _n from x _n next time.

It should be noted that the corresponding relationship between each variable: the gas pipeline inlet pressure and temperature sensor 2 can only detect the gas pressure and temperature in front of the electromagnetic shut-off valve 3; the combination of the position sensor and the pressure sensor 4 can measure the proportional valve 5 The actual opening, that is, x _n , the subscript n is the number of times the proportional valve is closed as mentioned above, and n-1 represents the last time the proportional valve was closed. They will not be described in detail here, and they are all within the scope of protection of this application; at the same time, The combination of position sensor and pressure sensor 4 can also measure the gas pressure at the air inlet of the proportional valve 5. The gas pipeline outlet pressure and temperature sensor 6 can measure the gas pressure at the outlet of the proportional valve 5 . All thresholds A, B, C, D, etc. are set values written into the computer board based on certain test results or experience. It is a value that will not change as long as it is determined. The specific values will not be described one by one here, but will depend on the actual situation, and are all within the protection scope of this application.

In this embodiment, the pressure and temperature sensors before and after the valve, the proportional valve position sensor, the electromagnetic cut-off valve, etc. on the gas proportional valve are used to perform zero-point self-learning electronic control logic control of the gas opening and closing positions to achieve the normal opening of the gas proportional valve. With safety shutdown, it prevents gas leakage and pipeline blockage, and reduces false alarms of related faults. Compared with existing control strategies, it is more comprehensive and accurate.

Another embodiment of the present application also provides a natural gas engine gas proportional valve control device.

Natural gas engine gas proportional valve control device, including:

The first judgment unit is used to judge whether the gas proportional valve currently meets the zero position self-learning condition.

A unit for accumulating the number of valve closing times, if the judgment result of the first judgment unit is yes, determining that the current cumulative number of valve closing times of the gas proportional valve has been detected.

The second judgment unit is used to judge whether the current cumulative number of valve closing times is greater than the preset valve closing threshold.

A correction unit configured to, if the judgment result of the second judgment unit is yes, correct the gas proportional valve when it is detected that the current actual closing position of the gas proportional valve is within the zero position threshold range.

In practical applications, the correction unit is used to correct the gas proportional valve, specifically for:

Determine whether y _n -z _n is greater than the zero offset threshold.

If yes, then determine z _n =z _n-1 +D; if not, then determine z _n =y _n .

Determine w _n =x _n- z _n .

Among them, D is the zero offset threshold; y _n is the second parameter when closing the valve for the nth time; z _n is the zero self-learning value when closing the valve for the nth time; z _n-1 is the n-1th valve closing The zero-point self-learning value at the time; w _n is the valve zero-point correction value when the valve is closed for the nth time.

In practical applications, it also includes:

A fault unit configured to determine that a zero point occurs in the gas proportional valve when it is detected that the current actual closing position of the gas proportional valve is outside the zero position threshold range if the judgment result of the second judgment unit is yes. Offset failure.

In practical applications, the first judgment unit is used to judge whether the gas proportional valve currently meets the zero position self-learning condition, specifically for:

When the engine enters the reverse towing condition, it is determined whether the inlet and outlet pressure difference of the gas proportional valve is less than the preset pressure drop threshold, the set opening of the gas proportional valve is less than the zero setting threshold, and, The current actual closing position is within the zero position threshold range.

For details on the working process and principles of each of the above units, please refer to the gas proportional valve control method for natural gas engines provided in the above embodiments. They will not be described in detail here, and they are all within the scope of the present application.

In this embodiment, the first judgment unit judges whether the gas proportional valve currently satisfies the zero position self-learning condition; if the accumulated number of valve closing times unit determines that the first judgment unit is yes, it determines that the current valve closing of the gas proportional valve is detected. The cumulative number of times; the second judgment unit judges whether the current cumulative number of valve closing times is greater than the preset valve closing threshold; the correction unit, if the judgment result of the second judgment unit is yes, when it detects that the current actual closing position of the gas proportional valve is at the zero position When the gas proportional valve is within the threshold range, the gas proportional valve is corrected; thus, when the gas proportional valve deviates from the zero point, the opening of the gas proportional valve can be corrected so that it can still provide a suitable and correct gas supply flow to prevent gas leakage and pipe It reduces road congestion and reduces false alarms. It is more comprehensive and accurate than the existing control strategy.

The features described in each embodiment in this specification can be replaced or combined with each other. The same and similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple. For relevant details, please refer to the partial description of the method embodiment. The system and system embodiments described above are only illustrative, in which the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, It can be located in one place, or it can be distributed over multiple network elements. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. Persons of ordinary skill in the art can understand and implement the method without any creative effort.

Those skilled in the art may further realize that the units and algorithm steps of each example described in connection with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of both. In order to clearly illustrate the possible functions of hardware and software, Interchangeability, in the above description, the composition and steps of each example have been generally described according to functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Skilled artisans may implement the described functionality using different methods for each specific application, but such implementations should not be considered to be beyond the scope of the present invention.

The above description of the disclosed embodiments enables those 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 practiced in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not 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. The control method of the fuel gas proportional valve of the natural gas engine is characterized by comprising the following steps of:

judging whether the gas proportional valve currently meets a zero position self-learning condition or not;

if yes, determining the current closing frequency of the gas proportional valve;

judging whether the current valve closing accumulated times are larger than a preset valve closing threshold value or not;

and if the current valve closing accumulated 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 in the zero position threshold range.

2. The method of controlling a gas proportional valve of a natural gas engine according to claim 1, wherein correcting the gas proportional valve comprises:

judging whether yn-zn is larger than a zero offset threshold value or not;

if yes, then zn=zn-1+d is determined; if not, then zn=yn is determined;

determining wn = xn-zn;

wherein D is a zero offset threshold; yn is a second parameter when the valve is closed for the nth time; zn is a zero self-learning value when the valve is closed for the nth time; zn-1 is a zero self-learning value when the valve is closed for the n-1 th time; wn is the valve zero point correction value when the valve is closed for the nth time; xn is the current actual closed position.

3. The method of claim 2, wherein the second parameter is a current actual closed position of the gas proportional valve.

4. The method according to claim 1, wherein after determining whether the current valve closing integrated number is greater than a preset valve closing threshold, if the current valve closing integrated number is greater than the preset valve closing threshold, further comprising:

and when the current actual closing position of the fuel gas proportional valve is detected to be out of the zero position threshold range, judging that the fuel gas proportional valve has zero offset faults.

5. The method according to claim 2, wherein after determining whether the current valve closing integrated number is greater than a preset valve closing threshold, if determining whether the current valve closing integrated number is greater than the preset valve closing threshold, further comprising:

and determining that the second parameter is 0 and the zero point correction value is the current actual closing position.

6. The control method of a natural gas engine fuel gas proportional valve according to any one of claims 1 to 5, wherein determining whether the fuel gas proportional valve currently satisfies a zero position self-learning condition includes:

when the engine enters a reverse-dragging working condition, judging whether the inlet-outlet pressure difference of the fuel gas proportional valve is smaller than a preset pressure drop threshold value, wherein the set opening degree of the fuel gas proportional valve is smaller than a zero point set threshold value, and the current actual closing position is in a zero point position threshold value range.

7. A natural gas engine gas proportional valve control device, comprising:

the first judging unit is used for judging whether the fuel gas proportional valve currently meets the zero position self-learning condition;

the accumulated valve closing frequency unit is used for determining that the current valve closing accumulated frequency of the fuel gas proportional valve is detected if the judgment result of the first judgment unit is yes;

the second judging unit is used for judging whether the current valve closing accumulated times are larger than a preset valve closing threshold value or not;

and the correction unit is used for correcting the fuel gas proportional valve when the current actual closing position of the fuel gas proportional valve is detected to be in the zero position threshold range if the judgment result of the second judgment unit is yes.

8. The natural gas engine fuel gas proportional valve control device according to claim 7, wherein the correction unit is configured to, when correcting the fuel gas proportional valve, specifically:

judging whether yn-zn is larger than a zero offset threshold value or not;

if yes, then zn=zn-1+d is determined; if not, then zn=yn is determined;

determining wn = xn-zn;

wherein D is a zero offset threshold; yn is a second parameter when the valve is closed for the nth time; zn is a zero self-learning value when the valve is closed for the nth time; zn-1 is a zero self-learning value when the valve is closed for the n-1 th time; and wn is a valve zero point correction value at the nth valve closing time.

9. The natural gas engine fuel gas proportional valve control device of claim 7, further comprising:

and the fault unit is used for judging that the gas proportional valve has zero offset fault 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 fuel gas proportional valve control device according to any one of claims 7 to 9, wherein the first judging unit is configured to, when judging whether the fuel gas proportional valve currently satisfies a zero position self-learning condition, specifically:

when the engine enters a reverse-dragging working condition, judging whether the inlet-outlet pressure difference of the fuel gas proportional valve is smaller than a preset pressure drop threshold value, wherein the set opening degree of the fuel gas proportional valve is smaller than a zero point set threshold value, and the current actual closing position is in a zero point position threshold value range.