Injection valve control method and control circuit of gas engine and gas inlet system

Abstract

The invention relates to the technical field of gas engine control, in particular to an injection valve control method and circuit of a gas engine and a gas inlet system. The injection valve control method comprises the steps that a lubricating oil solidification factor is determined according to the gas temperature, the environment temperature and the driving mileage; whether the lubricating oil solidification factor is larger than a preset risk threshold value or not is judged, if yes, first nozzle driving current is determined according to the lubricating oil deposition amount, and an injection valve is driven through the first nozzle driving current; and if not, the injection valve is driven by the second nozzle driving current. The risk coefficient, namely the lubricating oil solidification factor, of adhesion of solidified lubricating oil to the metering injection valve is determined based on the gas temperature, the environment temperature and the driving mileage. And under the condition that the lubricating oil solidification factor is larger than the preset risk threshold value, the lubricating oil deposition amount in the metering injection valve is predicted, the more the lubricating oil deposition amount is, the first nozzle driving current is correspondingly increased, and it is ensured that the injection valve can conduct fuel gas injection according to the preset duration and the preset opening degree.

Description

Technical Field

[0001] The present application relates to the field of gas engine control technology, and in particular to a gas engine injection valve control method, a control circuit, and a gas intake system. Background Art

[0002] The fuel supply system for a natural gas engine primarily consists of a gas tank, a gas shutoff valve, a pressure reducer, and a metered injection valve. High-pressure gas in the tank is delivered through the gas shutoff valve to the pressure reducer for decompression. The metered injection valve then injects a fixed amount of decompressed gas into the engine's intake system, according to the air-fuel ratio specified by the engine control system.

[0003] When the metering injection valve's coil is energized, the electromagnetic force of the armature overcomes the return spring's pull and the rising gas pressure, opening the valve and discharging gas. When the coil is de-energized, the armature returns to its original position under the return spring's pull and the gas pressure, closing the valve and stopping the gas flow.

[0004] The solenoid valve of the metering injection valve adopts PWM control, and the electromagnetic force is adjusted by PWM signals with different duty cycles, increasing the driving current when the gas pressure is high.

[0005] There is a metering injection valve control failure caused by lubricating oil migration in the natural gas engine fuel system.

[0006] Lubricant migration refers to the leakage of lubricant from the compressor unit into the natural gas during operation. Due to the molecular solubility differences between natural gas and lubricant, under high-pressure conditions, this migrated lubricant can also enter the metered injection valve.

[0007] In an environment of minus 40 degrees Celsius, the deposited lubricating oil forms a colloid in the pipeline, and then crystallizes and precipitates at the nozzle valve seat. At this time, the electromagnetic force of the solenoid valve is less than the sum of the return spring tension, the gas pressure and the viscosity of the lubricating oil, resulting in the solenoid valve being unable to spray according to the preset opening, causing the problem of insufficient engine gas intake.

[0008] The prior art gas engine jet control method does not take into account the lubricating oil viscosity problem in extremely cold environments.

[0009] In order to solve the problem of abnormal gas injection caused by the solidified lubricating oil sticking to the metering injection valve in an extremely cold environment, the present application provides an injection valve control method, a control circuit and a gas intake system for a gas engine. Summary of the Invention

[0010] To overcome the problems existing in the related art, the present application provides, in a first aspect, a method for controlling an injection valve of a gas engine, comprising: After receiving the engine start command, obtain the gas temperature, ambient temperature and mileage; Determine the lubricating oil solidification factor based on gas temperature, ambient temperature and mileage; Determine whether the lubricating oil solidification factor is greater than a preset risk threshold. If so, determine the first nozzle drive current according to the lubricating oil deposition amount, and drive the injection valve with the first nozzle drive current; if not, drive the injection valve with the second nozzle drive current.

[0011] In one embodiment, before determining the first nozzle driving current according to the lubricating oil deposit amount, the method further includes: Obtain gas pressure, coolant temperature, and lubricating oil pour point; The amount of lubricating oil deposits is determined based on the gas pressure, coolant temperature and lubricating oil pour point.

[0012] In one embodiment, determining the amount of lubricating oil deposits based on the fuel gas pressure, the coolant temperature, and the lubricating oil pour point specifically includes: Determine the lubricant oil deposition rate based on the gas temperature, lubricant oil pour point, and gas pressure; The lubricating oil deposition amount is determined according to the lubricating oil deposition rate.

[0013] In one embodiment, determining the first nozzle driving current according to the lubricating oil deposit amount specifically includes: Determine whether the gas temperature is lower than the preset temperature threshold, If yes, determining the first nozzle driving current according to the first correction coefficient and the lubricating oil deposit amount; If not, the first nozzle driving current is determined according to a second correction coefficient and the lubricating oil deposit amount.

[0014] In one embodiment, the injection valve control method further includes: after receiving an engine shutdown instruction, draining the gas in the gas pipeline.

[0015] In one embodiment, the exhausting of gas from the gas pipeline specifically includes: After receiving the engine start command, close the gas shut-off valve; Open the metering injection valve until the gas pipeline pressure is lower than the preset pressure threshold.

[0016] A second aspect of the present application provides an injection valve control circuit for a gas engine, comprising: a control unit and a monitoring unit; The monitoring unit is electrically connected to the temperature sensor and the pressure sensor in the gas pipeline, and the monitoring unit is used to send monitoring data to the control unit; The control unit is electrically connected to the monitoring unit, and the control unit is used to execute the steps of the injection valve control method described in the first aspect of the present application according to the monitoring data.

[0017] A third aspect of the present application provides a gas intake system for a gas engine, comprising the injection valve control circuit described in the second aspect of the present application.

[0018] The technical solution provided by this application may have the following beneficial effects: After receiving an engine start command, this application determines the risk factor of solidified lubricant sticking to the metering injection valve, known as the lubricant solidification factor, based on gas temperature, ambient temperature, and mileage. If the lubricant solidification factor exceeds a preset risk threshold, the amount of lubricant deposited in the metering injection valve is predicted. The greater the amount of lubricant deposited, the higher the current driving the first nozzle, increasing the force required to open the solenoid valve. During engine intake, the metering injection valve is controlled by the first nozzle drive current to prevent insufficient gas flow in the cylinder.

[0019] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0021] Figure 1 Schematic diagram of the flow of the injection valve control method shown in an embodiment of the present application; Figure 2 Schematic diagram of a flow chart of a lubricating oil deposit amount calculation step of an injection valve control method according to an embodiment of the present application; Figure 3 This is another flowchart of the lubricating oil deposit amount calculation step in the injection valve control method according to an embodiment of the present application; Figure 4 This is a flow chart of the gas exhaust step of the injection valve control method according to an embodiment of the present application. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. Instead, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0023] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0024] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0025] Example 1 There is a small amount of leaked lubricating oil in the intake pipe of the gas engine. In an environment of minus 40 degrees Celsius, the lubricating oil solidifies near the injection port of the metering injection valve, causing the metering injection valve to be unable to open normally.

[0026] The conventional gas engine injection control method does not take into account the adhesion of solidified lubricating oil to the metering injection valve nozzle in an extremely cold environment, resulting in insufficient gas intake during actual nozzle driving.

[0027] An embodiment of the present application provides a method for controlling an injection valve of a gas engine, which can solve the problem of abnormal gas injection caused by the adhesion of solidified lubricating oil to the metering injection valve in an extremely cold environment.

[0028] Figure 1 Schematic diagram of the steps of the injection valve control method shown in an embodiment of the present application.

[0029] The gas intake system of a gas engine consists of a high-pressure gas cylinder, a shut-off valve, a filter, and a metered injection valve, arranged in sequence along the gas flow line. The metered injection valve is equipped with an air inlet, an air outlet, an injection valve, a gas pressure sensor, a gas temperature sensor, and an injection valve ECU. This ECU is electrically connected to the engine ECU, and the injection valve ECU injects a fixed amount of gas into the intake pipe based on signals from the engine ECU.

[0030] In the embodiment of the present application, when the valve core of the injection valve is opened, it needs to overcome the tension of the return spring, the gas pressure, and the possible adhesion of the lubricating oil.

[0031] like Figure 1As shown, the injection valve control method of the technical solution of the present application includes the following steps: S1. After receiving the engine start command, obtain the gas temperature, ambient temperature and mileage; S2. determining a lubricating oil solidification factor according to the gas temperature, ambient temperature, and mileage; In order to assess the risk of lubricant solidification in a metered injection valve, the present application determines whether to execute the nozzle drive current by calculating the lubricant solidification factor. For example, the calculation formula of the lubricant solidification factor is:

[0032] in, is the pour point of the lubricating oil, is the gas temperature, is the ambient temperature, For mileage.

[0033] In an embodiment of the present application, a preset risk threshold indicates the risk of lubricating oil solidification in the pipeline system, and the lubricating oil solidification factor is calculated by monitoring the minimum value of the ambient temperature or gas temperature, the lubricating oil pour point, and the mileage.

[0034] Exemplarily, the preset risk threshold is 1. When the lubricating oil solidification factor is greater than 1, the metering injection valve is driven by the first nozzle driving current.

[0035] S3, determining whether the lubricating oil solidification factor is greater than a preset risk threshold, If yes, determining a first nozzle driving current according to the amount of lubricating oil deposit, and driving the injection valve with the first nozzle driving current; If not, the injection valve is driven by the second nozzle driving current.

[0036] It is understood that the first and second nozzle drive currents are controlled by PWM signals. When the lubricant solidifies, the duty cycle of the PWM signal is increased to output the first nozzle drive current. When the lubricant is not solidified, the second nozzle drive current is set to the rated input current of the metering injection valve model.

[0037] Further, such as Figure 2 As shown, before determining the first nozzle driving current according to the lubricating oil deposit amount, the method further includes: S301, obtaining gas pressure, coolant temperature, and lubricating oil pour point; S302: Determine the amount of lubricating oil deposits according to the fuel gas pressure, the coolant temperature, and the lubricating oil pour point.

[0038] Furthermore, if Figure 3 As shown, step S302 specifically includes: S3021. Determine the lubricating oil deposition rate based on the fuel gas temperature, the lubricating oil pour point, and the fuel gas pressure; S3022: Determine the lubricating oil deposition amount according to the lubricating oil deposition rate.

[0039] For example, the calculation model of lubricating oil deposit amount is:

[0040] in, is the amount of lubricating oil deposited, is the lubricating oil deposition rate, is the coolant temperature, The working time of the nozzle, is a constant, .

[0041] The lubricating oil deposition volume is the solid phase volume of the lubricating oil in the metered injection valve, specifically the solidified lubricating oil volume in the nozzle area. In the embodiment of the present application, the solidified lubricating oil volume in the nozzle area is predicted by the calculation model of the lubricating oil deposition volume. Correction for lubricant deposition rate The volume of solidified lubricating oil accumulated in the nozzle area of ​​the metering injection valve after leaving the factory is obtained by integrating the lubricating oil over a certain period of time.

[0042] In actual operating conditions, lubricant begins to deposit after the engine is first started. This embodiment of the present application uses the aforementioned lubricant deposition calculation model to calculate the volume of solidified lubricant deposited during the nozzle's operating time, i.e., the lubricant deposition amount. A greater amount of lubricant deposition indicates a greater sticking force on the metered injection valve's spool, necessitating the calculation of the compensation current based on the lubricant deposition amount.

[0043] Exemplarily, the lubricant deposition rate is calculated by the following formula:

[0044] in, is the pour point of the lubricating oil, is the gas temperature, is the gas pressure.

[0045] After the lubricating oil deposit amount is calculated, the rated drive current of the metering injection valve is current compensated.

[0046] Furthermore, in step S3, determining the first nozzle driving current according to the lubricating oil deposition amount specifically includes: Determine whether the gas temperature is lower than the preset temperature threshold, If yes, determining the first nozzle driving current according to the first correction coefficient and the lubricating oil deposit amount; If not, the first nozzle driving current is determined according to a second correction coefficient and the lubricating oil deposit amount.

[0047] The viscosity of lubricating oil varies in different low temperature ranges. The embodiment of the present application sets different correction coefficients according to the viscosity of lubricating oil in different low temperature ranges, and increases the compensation current to cope with the extremely cold environment of -15 degrees Celsius. For example, the calculation formula of the compensation current is:

[0048] Among them, the first correction coefficient is 0.5 and the second correction coefficient is 0.3.

[0049] In an embodiment of the present application, the first nozzle driving current is equal to the sum of the rated driving current and the compensation current.

[0050] Furthermore, in order to prevent excess lubricating oil from remaining in the metered injection valve after the engine is shut down, the injection valve control method of the embodiment of the present application further includes step S4: After receiving the engine shutdown command, the gas in the gas pipeline is emptied.

[0051] Specifically, such as Figure 4 As shown, step S4 includes: S401, after receiving the engine start command, closing the gas shut-off valve; S402: Open the metering injection valve until the gas pipeline pressure is lower than the preset pressure threshold.

[0052] After receiving an engine start command, this embodiment of the present application determines the risk factor of solidified lubricant oil sticking to the metering injection valve, known as the lubricant solidification factor, based on gas temperature, ambient temperature, and mileage. If the lubricant solidification factor exceeds a preset risk threshold, the amount of lubricant deposited in the metering injection valve is predicted. The greater the amount of lubricant deposited, the higher the current driving the first nozzle, increasing the force required to open the solenoid valve. During engine intake, the metering injection valve is controlled by the first nozzle drive current to prevent insufficient gas flow in the cylinder.

[0053] Example 2 A gas engine injection valve control circuit includes: a control unit and a monitoring unit; The monitoring unit is electrically connected to the temperature sensor and the air pressure sensor in the gas pipeline, and is used to send monitoring data to the control unit; the monitoring data includes the gas pressure, gas temperature, coolant temperature, ambient temperature and mileage as described in the embodiment.

[0054] It can be understood that the monitoring unit may be a signal acquisition circuit of a sensor.

[0055] The control unit is electrically connected to the monitoring unit, and the control unit is configured to execute the steps of the injection valve control method described in the first embodiment according to the monitoring data.

[0056] Example 3 A gas intake system for a gas engine includes the injection valve control circuit described in the second embodiment.

[0057] The gas intake system of the gas engine is connected in sequence along the intake pipeline with a high-pressure gas tank, a shut-off valve, a pressure reducer, a filter and a metering injection valve. The outlet of the metering injection valve is connected to the intake manifold of the gas engine. The metering injection valve is provided with an injection valve control circuit, and the injection valve control circuit performs gas metering injection based on the injection valve control method described in Example 1. The scheme of the present application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments. Those skilled in the art should also be aware that the actions and modules involved in the description are not necessarily required for this application. In addition, it can be understood that the steps in the method of the embodiment of the present application can be adjusted in sequence, merged and deleted according to actual needs, and the modules in the device of the embodiment of the present application can be merged, divided and deleted according to actual needs.

[0058] In addition, the method according to the present application may also be implemented as a computer program or a computer program product, which includes computer program code instructions for executing some or all of the steps in the above method of the present application.

[0059] Alternatively, the present application can also be implemented as a non-transitory machine-readable storage medium (or computer-readable storage medium, or machine-readable storage medium) on which executable code (or computer program, or computer instruction code) is stored. When the executable code (or computer program, or computer instruction code) is executed by a processor of an electronic device (or electronic device, server, etc.), the processor executes part or all of the steps of the above-mentioned method according to the present application.

[0060] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the application herein may be implemented as electronic hardware, computer software, or combinations of both.

[0061] The flow charts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems and methods according to multiple embodiments of the present application. In this regard, each box in the flow chart or block diagram can represent a part of a module, program segment or code, and the part of the module, program segment or code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0062] The embodiments of the present application have been described above. The above description is illustrative and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to the technology in the market, or to enable other persons skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for controlling an injection valve of a gas engine, characterized in that: include: After receiving the engine start command, obtain the gas temperature, ambient temperature and mileage; Determine the lubricating oil solidification factor based on gas temperature, ambient temperature and mileage; determining whether the lubricating oil solidification factor is greater than a preset risk threshold, and if so, determining a first nozzle driving current according to the amount of lubricating oil deposited, and driving the injection valve with the first nozzle driving current; If not, the injection valve is driven by the second nozzle driving current.

2. A method for controlling an injection valve of a gas engine according to claim 1, characterized in that: Before determining the first nozzle driving current according to the lubricating oil deposit amount, the method further includes: Obtain gas pressure, coolant temperature, and lubricating oil pour point; The amount of lubricating oil deposits is determined based on the gas pressure, coolant temperature and lubricating oil pour point.

3. The method for controlling the injection valve of a gas engine according to claim 2, characterized in that: The method of determining the amount of lubricating oil deposits according to the fuel gas pressure, the coolant temperature and the lubricating oil pour point specifically includes: Determine the lubricant oil deposition rate based on the gas temperature, lubricant oil pour point, and gas pressure; The lubricating oil deposition amount is determined according to the lubricating oil deposition rate.

4. The method for controlling the injection valve of a gas engine according to claim 1, characterized in that: Determining a first nozzle driving current according to the lubricating oil deposit amount specifically includes: Determine whether the gas temperature is lower than the preset temperature threshold, If yes, determining the first nozzle driving current according to the first correction coefficient and the lubricating oil deposit amount; If not, the first nozzle driving current is determined according to a second correction coefficient and the lubricating oil deposit amount.

5. The method for controlling the injection valve of a gas engine according to claim 1, characterized in that: Also includes: After receiving the engine shutdown command, the gas in the gas pipeline is emptied.

6. The method for controlling the injection valve of a gas engine according to claim 5, characterized in that: The exhausting of gas from the gas pipeline specifically includes: After receiving the engine start command, close the gas shut-off valve; Open the metering injection valve until the gas pipeline pressure is lower than the preset pressure threshold.

7. A gas engine injection valve control circuit, characterized in that: include: control unit and monitoring unit; The monitoring unit is electrically connected to the temperature sensor and the pressure sensor in the gas pipeline, and the monitoring unit is used to send monitoring data to the control unit; The control unit is electrically connected to the monitoring unit, and the control unit is configured to execute the steps of the injection valve control method according to any one of claims 1 to 6 according to the monitoring data.

8. A gas intake system for a gas engine, characterized in that: The invention comprises the injection valve control circuit according to claim 7.

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