CN112267939B - FPLG stable operation control method and system based on vibration acceleration signal - Google Patents
FPLG stable operation control method and system based on vibration acceleration signal Download PDFInfo
- Publication number
- CN112267939B CN112267939B CN202011140896.5A CN202011140896A CN112267939B CN 112267939 B CN112267939 B CN 112267939B CN 202011140896 A CN202011140896 A CN 202011140896A CN 112267939 B CN112267939 B CN 112267939B
- Authority
- CN
- China
- Prior art keywords
- displacement
- average
- vibration
- target
- starting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000001133 acceleration Effects 0.000 title claims abstract description 66
- 238000000034 method Methods 0.000 title claims abstract description 34
- 238000006073 displacement reaction Methods 0.000 claims abstract description 102
- 238000002485 combustion reaction Methods 0.000 claims abstract description 59
- 238000010248 power generation Methods 0.000 claims abstract description 37
- 208000006011 Stroke Diseases 0.000 claims abstract description 29
- 230000008569 process Effects 0.000 claims description 12
- 238000003860 storage Methods 0.000 claims description 10
- 238000005259 measurement Methods 0.000 claims description 7
- 238000004364 calculation method Methods 0.000 claims description 4
- 239000004606 Fillers/Extenders Substances 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 10
- 230000006870 function Effects 0.000 description 8
- 238000004590 computer program Methods 0.000 description 7
- 230000005284 excitation Effects 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 230000007246 mechanism Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 230000004044 response Effects 0.000 description 3
- 238000004088 simulation Methods 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- 239000000567 combustion gas Substances 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000021715 photosynthesis, light harvesting Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
Images
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B63/00—Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices
- F02B63/04—Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices for electric generators
- F02B63/041—Linear electric generators
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B71/00—Free-piston engines; Engines without rotary main shaft
- F02B71/04—Adaptations of such engines for special use; Combinations of such engines with apparatus driven thereby
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B77/00—Component parts, details or accessories, not otherwise provided for
- F02B77/08—Safety, indicating, or supervising devices
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B77/00—Component parts, details or accessories, not otherwise provided for
- F02B77/08—Safety, indicating, or supervising devices
- F02B77/085—Safety, indicating, or supervising devices with sensors measuring combustion processes, e.g. knocking, pressure, ionization, combustion flame
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
The invention provides a vibration acceleration signal-based FPLG stable operation control method and a system, which belong to the technical field of range extenders of new energy vehicles, calculate target dragging force required by a rotor to move to target displacement according to target displacement and starting frequency to be met by the rotor, and control ignition starting of an engine according to starting conditions; acquiring vibration acceleration signals after starting in real time, and calculating and describing the average displacement of the average indicated pressure in the cylinder; and calculating the target power generation amount of the primary stroke according to the linear relation between the average displacement and the average indication pressure and the linear relation between the average indication pressure and the power generation amount, and controlling the voltage of the end of the generator according to the target power generation amount so as to control the output current to meet the power generation requirement. According to the invention, the average indicated pressure of combustion in the cylinder is judged through the vibration acceleration signal, and the generated energy is controlled according to the average indicated pressure, the characteristic parameter of the vibration acceleration signal and the relation between the average indicated pressure and the generated energy, so that the mover of the FPLG can reach the vicinity of the set top dead center, and the stable combustion of the FPLG is realized.
Description
Technical Field
The invention relates to the technical field of range extenders of new energy vehicles, in particular to a method and a system for controlling stable operation of a FPLG based on a vibration acceleration signal.
Background
The Free Piston Linear Generator (FPLG) converts heat energy generated by engine combustion into electric energy through the motor and outputs the electric energy, can be used as an Auxiliary Power Unit (APU) of an extended-range hybrid electric vehicle, has the advantages of higher thermal efficiency, lower friction loss, low oil consumption and the like compared with a traditional engine, and is an important research direction of a new energy automobile power system in the future.
The FPLG consists of a linear motor and an engine. Different from the traditional engine, the engine in the FPLG structurally omits a crank link mechanism and a flywheel mechanism, so that the structure is simplified, the friction energy consumption is reduced, and the heat efficiency is improved. The engine and the linear motor are connected in series, and heat energy generated by combustion is converted into required energy through the motor to be output. The engine piston connecting rod and the motor rotor are connected in series to form a system moving component, namely a rotor assembly for short. However, due to the lack of mechanical limitation of a crank link mechanism, the motion of the rotor assembly of the FPLG is influenced by factors such as combustion gas force, electromagnetic force, friction force and the like, if the motion of the rotor assembly of the FPLG is not controlled, the position of the top dead center which can be reached by each cycle of the rotor assembly is different due to combustion cycle variation, and when the top dead center of some cycles cannot generate enough compression ratio, an engine can generate a fire phenomenon or a combustion extremely poor phenomenon, so that the operation of the FPLG is unstable and even the FPLG is stopped.
Disclosure of Invention
The invention aims to provide a control method for reflecting a real-time combustion process in an engine cylinder through a vibration acceleration signal of the surface of an engine body so as to determine target power generation amount, adjusting and controlling actual power generation amount according to the target power generation amount and realizing stable operation of an FPLG (floating gate liquid crystal), so as to solve at least one technical problem in the background art.
In order to achieve the purpose, the invention adopts the following technical scheme:
on one hand, the invention provides a vibration acceleration signal-based FPLG stable operation control method, which comprises the following steps:
step S110: calculating target dragging force required by the mover to move to the target displacement according to the target displacement and the starting frequency which are required by the mover, and controlling the ignition and starting of the engine according to the starting condition;
step S120: acquiring vibration acceleration signals of the started rotor in real time, and calculating and describing the average displacement of the average indicated pressure in the cylinder;
step S130: and calculating the target generating capacity of the primary stroke according to the linear relation between the average displacement and the average indicating pressure and the linear relation between the average indicating pressure and the generating capacity, and controlling the voltage of the generator terminal according to the target generating capacity so as to control the output current to meet the generating requirement and realize the stable operation of the FPLG.
Preferably, the step S110 specifically includes:
the rotor is arranged to drag left first, and the drag force F required by the rotor to move from the middle of the stroke to the target displacement is calculatedLeft side ofAccording to FLeft side ofDragging the rotor to move, judging whether the first dragging half-stroke rotor can reach the target displacement, and if not, dragging the next stroke;
if the target displacement is reached, recording the time used in the process, calculating the motion frequency of the stroke mover, comparing the motion frequency with the starting frequency, and if the starting frequency is not met, continuing the dragging of the next stroke; if the engine start-up request meets the requirement, the control system controls the engine to ignite and burn, and the start is finished.
Preferably, when the target displacement and the movement frequency can not meet the starting condition, the dragging force F required from the left dead center to the right target displacement is calculatedRight sideAnd feeds back the power to the control system and controls the motor to provide a right dragging force FRight sideIf the right dead center position which can be reached by the rotor in the process does not meet the target displacement, dragging for the third time;
and if the position of the right side dead center meets the target displacement, calculating whether the moving frequency of the mover of the stroke meets the starting frequency, if not, dragging for the third time, and if so, controlling the engine to ignite and burn by the control system, and finishing the starting.
Preferably, the step S120 includes:
calculating and describing the vibration displacement of IMEP according to the average indicated pressure and by combining the linear relation between the vibration displacement before the peak pressure after the combustion starting point and the in-cylinder pressure; and the average displacement of the IMEP can be described by combining the second differential relation of the vibration displacement and the vibration acceleration.
Preferably, the average indicated pressure can be expressed as follows, according to the principles of internal combustion engines:
wherein, VhRepresenting the total cylinder volume, pi、pi-1Respectively representing in-cylinder pressures at i and i-1, Vi、Vi-1Indicates the cylinder volume at time i, i-1;
the vibration displacement before the peak pressure after the combustion starting point and the in-cylinder pressure are in a linear relation, and then the vibration displacement characteristic parameters describing IMEP are as follows:
wherein S ismeanRepresenting a characteristic parameter of vibration displacement, Si、Si-1Respectively show the vibration displacement of the cylinder at the time i and i-1.
Preferably, in combination with the second order differential relationship between vibrational displacement and vibrational acceleration, the average displacement describing IMEP can be described as:
wherein S is1Representing the displacement, v, at the first moment of the vibration measurement period1Representing the speed at the first moment of the vibration measurement period, akAnd the vibration acceleration at the kth moment is represented, n is the total point number of the moment of the selected section of vibration acceleration, i, j, k is the element of (1, 2.. eta., n).
In a second aspect, the present invention provides a FPLG stable operation control system based on a vibration acceleration signal, comprising:
the starting module is used for calculating a target dragging force required by the mover to move to a target displacement according to the target displacement and the starting frequency which are required by the mover, and controlling the ignition starting of the engine according to a starting condition;
and an average displacement calculation module. The system is used for acquiring vibration acceleration signals of the started rotor in real time and calculating and describing the average displacement of the average indicated pressure in the cylinder;
the target power generation amount calculating module is used for calculating the target power generation amount of one stroke according to the linear relation between the average displacement and the average indicating pressure and the linear relation between the average indicating pressure and the power generation amount;
and the control module is used for controlling the voltage of the generator terminal according to the target generated energy so as to control the output current to meet the power generation requirement and realize the stable operation of the FPLG.
In a third aspect, the invention provides a non-transitory computer readable storage medium comprising instructions for performing the method as described above.
In a fourth aspect, the invention provides an electronic device comprising a non-transitory computer readable storage medium as described above; and one or more processors capable of executing the instructions of the non-transitory computer-readable storage medium.
In a fifth aspect, the present invention provides an electronic device comprising means for performing the method as described above.
The invention has the beneficial effects that: the average indicating pressure of combustion in the cylinder is judged through the vibration acceleration signal, on one hand, the acceleration sensor is convenient to install, and the real-time operability is strong; on the other hand, according to the average indicated pressure, the vibration acceleration signal characteristic parameter and the relation between the average indicated pressure and the power generation amount, the expected power generation amount can be determined according to the real-time combustion condition, and therefore the rotor of the FPLG can reach the vicinity of the set top dead center, and stable combustion of the FPLG is achieved.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic view of a back-mounted FPLG stable operation control test installation structure according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a linear relationship between the average indicated pressure and the power generation amount according to the embodiment of the invention.
FIG. 3 is a diagram illustrating a comparison curve between a vibration acceleration signal and a second derivative of an in-cylinder pressure under a certain condition according to an embodiment of the present invention.
Fig. 4 is a flowchart of an FPLG stable operation control method based on a vibration acceleration signal according to an embodiment of the present invention.
Wherein: 2-a linear motor; 4-a connecting flange; 1-left cylinder; 3-right cylinder; 10-a piston; 11-a connecting rod; 12-a mover; 7-a mover assembly; 5-a bracket; 6-test bed; 8-a position sensor; 9-piezoelectric vibration acceleration sensor.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below by way of the drawings are illustrative only and are not to be construed as limiting the invention.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
For the purpose of facilitating an understanding of the present invention, the present invention will be further explained by way of specific embodiments with reference to the accompanying drawings, which are not intended to limit the present invention.
It should be understood by those skilled in the art that the drawings are merely schematic representations of embodiments and that the elements shown in the drawings are not necessarily required to practice the invention.
Example 1
The embodiment 1 of the invention provides a method for controlling stable operation of FPLG based on vibration acceleration signals, which comprises the steps of obtaining real-time combustion state information in an engine cylinder by analyzing vibration acceleration signals on the surface of an engine body, determining a cyclic target power generation amount based on the in-cylinder combustion state information, adjusting actual power generation according to the target power generation amount, enabling a rotor to operate near an ideal position, and ensuring stable operation of the FPLG.
In this embodiment, a description will be given of a back-set FPLG. At present, an existing back-mounted engine structure is arranged at two ends of a core shaft of a generator, a linear motor is arranged in the middle of the core shaft, and the linear motor has two functions of a motor and a generator. The rotor component comprises a piston, a connecting rod, a motor rotor and the like.
In the starting process, the linear motor serves as a motor to provide dragging force in different directions to drag the piston to reciprocate, the position sensor judges whether the upper dead center position, the movement frequency and the like of the rotor meet the starting requirements or not by monitoring the movement information of the rotor assembly, if so, the engine ignites and burns, and the linear motor is converted into electric energy output by the generator.
After the system is started, the system enters a stable operation working condition, the engine burns to generate energy, one part of the energy generated by burning is used for generating electricity, one part of the energy is converted into kinetic energy of the rotor, and the other part of the energy is converted into heat energy to be dissipated (friction and heat dissipation). When the system stably runs, the working frequency of the system also needs to be stabilized near a certain value, so that the kinetic energy which the rotor assembly reaches a specified position in each cycle is stable, the heat energy dissipation in each cycle is almost stable, but the combustion energy generated in each cycle is unstable due to the combustion cycle change, and therefore, the power generation amount needs to be adjusted according to the real-time in-cylinder combustion condition to ensure the stable operation of the FPLG.
According to the principle of the internal combustion engine, the average indicated pressure (IMEP) can describe the power capacity of the pressure in the cylinder, when the FPLG is stable in operation condition, the mover can reach the design top dead center position to ensure the stable operation of the system because the kinetic energy and the heat energy which the mover should have are basically stable in dissipation, the power generation amount is adjusted according to the real-time combustion condition, and the relation necessarily exists between the IMEP representing the combustion power capacity and the power generation amount. Analysis shows that there is an approximately linear relationship between IMEP and stroke power generation. FIG. 2 shows IMEP and power generation relationship obtained by simulation during steady operation of certain FPLG engine. Based on the approximate linear relation, the stroke target power generation amount can be determined through the IMEP value corresponding to real-time combustion, and then the power generation amount is judged and adjusted, so that the purpose of stabilizing the stable operation of the FPLG is achieved.
According to the mechanics principle and the mechanical vibration principle, the combustion gas force in the cylinder directly acts on the rotor and the cylinder cover, and the vibration signal on the surface of the cylinder cover can effectively reflect the excitation change.
The surface vibration signals are divided into vibration displacement, velocity and acceleration signals. The surface vibration displacement signal is a low-frequency signal, combustion information can be submerged, speed can reflect medium and low frequency information, certain interference information easily exists, acceleration mainly reflects high-frequency information, and the acceleration sensor is small, exquisite and convenient and easy to install. Therefore, the present embodiment selects the vibration acceleration signal to reflect the in-cylinder combustion process.
Under an ideal condition without other interference, before the peak value of the in-cylinder pressure after the combustion starting point, the vibration displacement of the surface of the engine and the in-cylinder pressure are in a linear relation, namely the vibration displacement can linearly describe the change of the in-cylinder pressure, so that the in-cylinder combustion state information can be described by the vibration displacement.
However, due to the influence of the measured vibration displacement signal including the low frequency interference information, the amount related to the combustion information in the measured vibration displacement signal may be overwhelmed by the interference information. The vibration acceleration is the second derivative of the vibration displacement and can reflect the change of the vibration speed, the vibration speed can reflect the change of the displacement, after the two derivatives of the displacement, the low-frequency interference information in the actually measured vibration displacement almost becomes zero, and the displacement information related to combustion excitation is reserved, so that the vibration acceleration information can effectively reflect the in-cylinder combustion information. According to the micro-integral theory and the relation between the vibration displacement and the pressure in the cylinder, the vibration acceleration signal of the surface of the cylinder cover is processed, and the vibration characteristic parameter describing the IMEP in the cylinder can be extracted.
According to internal combustion engine principles, the average indicated pressure may be expressed as follows:
in the formula VhIs the total volume of the cylinder; p is a radical ofi、pi-1Is the in-cylinder pressure at time i, i-1; vi、Vi-1Is the cylinder internal volume at time i, i-1.
Ideally, the vibration displacement before the peak pressure after the combustion start point and the in-cylinder pressure are linearly related to each other, and therefore, the vibration displacement S can be usediIn place of p in formula (1)iAnd obtaining a vibration displacement characteristic parameter capable of describing IMEP:
in the formula SmeanIs a vibration displacement characteristic parameter, referred to herein as the mean displacement; si、Si-1The vibration displacement of the cylinder body at the time of i and i-1, S is the linear relation between the displacement and the pressure in the cylindermeanAnd IMEP are also theoretically linear.
In combination with the second order differential relationship between the vibration displacement and the vibration acceleration, the average displacement describing IMEP can be obtained as follows:
in the formula S1And v1The displacement and speed of the first point in the vibration measurement period are the values which only affect the size of the result and do not affect the variation trend and can be set to be zero. a iskAnd n is the vibration acceleration of the selected section at the kth moment.
The results show the average displacement S calculated based on the vibration accelerationaAnd the IMEP obtained for the in-cylinder pressure, there is also an approximately linear relationship. Thus, the vibration acceleration parameter S can be based onaAnd the linear relation between IMEP and the generated energy is used for calculating the target generated energy required by the stroke, and feeding the value back to the control system, and the control system controls the output current to meet the power generation requirement by controlling the voltage of the generator terminal, thereby realizing the purpose of stable operation.
Example 2
In embodiment 2 of the present invention, a method for controlling stable operation of an FPLG based on a vibration acceleration signal is provided, in this embodiment, how to implement stable operation is described with a back-mounted FPLG, and a flowchart of the whole control process is shown in fig. 4.
The back-mounted FPLG structure is shown in figure 1, a linear motor 2 is arranged in the middle, the linear motor 2 is used for converting a generator and a motor, two sides of the linear motor 2 are respectively connected with a left cylinder 1 and a right cylinder 3 through a connecting flange 4 and a bolt, and a piston 10, a connecting rod 11 and a rotor 12 of the linear motor 2 form a rotor assembly 7. The integral device is fixed on a test bed 6 through a bracket 5.
The back-mounted structure is symmetrically arranged for the two-stroke engine, the position sensors 8 are arranged at different positions, and the magnetic grid sensors can also be directly arranged to detect the positions of the rotor assemblies. Piezoelectric vibration acceleration sensors 9 are installed on the surfaces of the left cylinder cover and the right cylinder cover to measure the vibration acceleration of the surfaces of the cylinder covers.
The control method described in this embodiment specifically controls the following processes:
when the rotor is started, the driving force required to be provided by the motor is determined according to the mass of the rotor, the piston is dragged to move to a specified ignition position (determined by a rotor displacement signal) and the starting frequency is reached; and if the starting condition is met, the controller controls the engine to ignite and burn.
The starting process comprises the following steps: the starting mover is generally positioned near the middle of the stroke under the action of force, the position of the mover in the middle of the stroke is set as a reference position, S is set to be 0, the displacement is negative when the mover moves leftwards, and the displacement is positive when the mover moves rightwards.
In order to ensure the smooth starting of the engine, the rotor moves leftwards or rightwards under the action of the dragging force of the linear motor, and when the motion frequency of the rotor and the top dead center position which can be reached by the rotor reach the starting condition of the engine, the engine can ignite and burn, and the starting condition is determined according to the requirements of the engine selected or designed in the FPGL.
Calculating the dragging force needed by the rotor to move to the target position, and setting the rotor to drag left first, so that the dragging force F needed by the rotor to move from the middle of the stroke to the target positionLeft side ofComprises the following steps:
in the formula, PLeft pressing(S) is the left cylinder gas compression pressure, which is a function of piston displacement S and can be calculated from empirical formulas; pPress rightThe compression pressure of the gas in the right cylinder is also a function of the displacement S of the piston and can be obtained by calculation according to an empirical formula; a represents the force bearing area of the piston and is a constant; sTargetDisplacement representing the position of a moving target of the rotor; ff right sideFriction when moving from right to left.
And recording the motion information in the first dragging half stroke (1/4 in one cycle) according to the position sensor, judging whether the mover can reach the target displacement, and if not, dragging in the next stroke. If the target displacement is reached, recording the time T used in the process1And calculating the motion frequency of the stroke mover,
and start upAnd comparing the frequency, and if the starting frequency is not met, continuing the dragging of the next stroke. If the engine start-up request meets the requirement, the control system controls the engine to inject oil, ignite and burn, and the start is finished.
When the target displacement and the target frequency can not meet the starting condition, calculating the dragging force F required from the left dead center to the right target positionRight side：
In the formula, Ff leftIs the friction force when moving from the left dead center to the right.
Will drag force FRight sideFeeding back the magnitude of the electromagnetic force to a control system, controlling a motor to provide a target electromagnetic force to the right, recording position information in the process and the time T required from a left dead center to a right dead center2If the right dead point position reached by the mover in the process is S2When S is2If the target displacement is not satisfied, dragging for the third time (from the right dead center to the left target position), and if S is not satisfied2Satisfying the target displacement, calculating the frequency of the stroke
Comparison f2And if the starting frequency is not met, dragging for the third time, and if the starting frequency is not met, controlling the system to inject oil, ignite and burn.
Repeating the steps, when the rotor can not meet the starting condition, the motor provides the left-direction and right-direction dragging forces calculated by the formulas (4) and (5) until the starting condition is met, and the engine ignites and burns to finish the starting process. After the FPLG system is started, an engine on one side ignites and burns, the generated energy pushes the rotor to overcome friction and move to the top dead center position on the other side, and meanwhile, a part of energy can be used for power generation.
Due to combustion cycle variation, even if the same operation working condition exists, different cycle combustion also has obvious difference, namely, the combustion energy generated by each cycle is different, and the motion frequency of the rotor can be regarded as a constant to ensure the stable working condition of the system, therefore, the kinetic energy required by the rotor, the heat dissipation of the system and the friction force of each cycle can be regarded as a constant, and the power generation amount needs to be adjusted to coordinate the influence of the combustion cycle variation when the rotor can reach the position near the design top dead center.
Once combustion is complete, the energy produced by combustion is constant and the power produced by the stroke has a target value. Under the condition that the same FPLG ensures stable operation, the target power generation amount and the in-cylinder combustion average indicated pressure IMEP are approximately in a linear relation, and the relation can be obtained based on simulation or experiment, and a graph of IMEP and power generation amount relation curve of certain FPLG is shown in figure 2, and the relation can be stored in a control system.
The IMEP is closely related to a vibration response signal caused by combustion excitation, and the combustion excitation directly acts on a cylinder cover, so that a vibration signal on the surface of the cylinder cover of the engine can directly reflect the combustion process in the cylinder.
Because the vibration response signal caused by the combustion excitation can be interfered by other excitation sources, the vibration response signal of the combustion period before the peak pressure after the combustion starting point is selected as the analysis basis.
FIG. 3 shows a vibration acceleration signal and a second derivative comparison curve of the in-cylinder pressure under a certain condition. In this embodiment, an ab-segment vibration signal is selected to calculate IMEP, where point a represents a combustion start point position and point b represents a peak pressure position.
Judging the position of the a point: and taking the mover movement displacement signal as a feedback signal, and when the control system judges that the mover moves to the combustion starting point position and ignites, the control system generates a trigger signal and starts to acquire a vibration acceleration signal corresponding to the surface of a cylinder cover of the combustion cylinder. Or may be determined from the first zero crossing before the peak vibration acceleration.
b, judging the position of the point: the point b corresponds to a peak pressure position, and since the mover assembly has the maximum acceleration at the time of occurrence of the peak pressure, the peak pressure position can be determined based on the position of the mover assembly at which the maximum acceleration occurs. When position b is determined, the system no longer collects the vibration acceleration signal.
Vibration acceleration filtering processing: as the vibration acceleration can reflect medium-high frequency information, the vibration acceleration signal of the actually measured combustion period also contains high-frequency interference information, and researches show that the signal below 2000Hz is closely related to the combustion process. Therefore, the collected combustion period vibration acceleration is low-pass filtered, and the cut-off frequency is selected to be 2000 Hz.
SaThe calculation of (2): calculating the average displacement S of vibration acceleration recognition according to the following formula (6) from the time interval from the start to the end of the vibration signal acquisitiona. And feeds this value back to the control system.
SaAnd IMEP, a MAP of the relationship can be obtained based on experimental or simulation results, and the results are stored in the control system.
S according to system feedbackaA value, and SaAnd IMEP relationship, IMEP and power generation relationship, which are shown in FIG. 2, and the target power generation W to be output by the system after the combustion is finished is interpolated.
According to the target generating capacity W, the control system controls the generator to timely adjust the actual generating capacity output to approach the target generating capacity so as to ensure the movement of the rotor and realize the stable operation of the FPLG.
In summary, according to the FPLG stable operation control method and system based on the vibration acceleration signal, the average in-cylinder combustion indicated pressure is judged through the vibration acceleration signal, so that on one hand, the acceleration sensor is convenient to install, and the real-time operability is strong; on the other hand, according to the average indicated pressure, the vibration acceleration signal characteristic parameter and the relation between the average indicated pressure and the power generation amount, the expected power generation amount can be determined according to the real-time combustion condition, and therefore the rotor of the FPLG can reach the vicinity of the set top dead center, and stable combustion of the FPLG is achieved.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure, and various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.
Although the present disclosure has been described with reference to the specific embodiments shown in the drawings, it is not intended to limit the scope of the present disclosure, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive faculty based on the technical solutions disclosed in the present disclosure.
Claims (8)
1. A FPLG stable operation control method based on vibration acceleration signals is characterized by comprising the following steps:
step S110: calculating target dragging force required by the mover to move to the target displacement according to the target displacement and the starting frequency which are required by the mover, and controlling the ignition and starting of the engine according to the starting condition;
step S120: acquiring vibration acceleration signals of the started rotor in real time, and calculating and describing the average displacement of the average indicated pressure in the cylinder; according to internal combustion engine principles, the average indicated pressure may be expressed as follows:
wherein, VhRepresenting the total cylinder volume, pi、pi-1Respectively representing in-cylinder pressures at i and i-1, Vi、Vi-1Indicates the cylinder volume at time i, i-1;
the vibration displacement before the peak pressure after the combustion starting point and the in-cylinder pressure are in a linear relation, and then the vibration displacement characteristic parameters describing IMEP are as follows:
wherein S ismeanRepresenting a characteristic parameter of vibration displacement, Si、Si-1Respectively representing the vibration displacement of the cylinder body at the time i and the time i-1;
combining the second order differential relationship between the vibrational displacement and the vibrational acceleration, the average displacement describing IMEP can be described as:
wherein S is1Representing the displacement, v, at the first moment of the vibration measurement period1Representing the speed at the first moment of the vibration measurement period, akRepresenting the vibration acceleration at the kth moment, wherein n is the total point number of the moment of the selected section of vibration acceleration, i, j, k is an element (1, 2.. multidot., n);
step S130: and calculating the target generating capacity of the primary stroke according to the linear relation between the average displacement and the average indicating pressure and the linear relation between the average indicating pressure and the generating capacity, and controlling the voltage of the generator terminal according to the target generating capacity so as to control the output current to meet the generating requirement and realize the stable operation of the FPLG.
2. The method for controlling stable operation of FPLG based on vibration acceleration signal according to claim 1, wherein the step S110 specifically comprises:
the rotor is arranged to drag left first, and the drag force F required by the rotor to move from the middle of the stroke to the target displacement is calculatedLeft side ofAccording to FLeft side ofDragging the rotor to move, judging whether the first dragging half-stroke rotor can reach the target displacement, and if not, dragging the next stroke;
if the target displacement is reached, recording the time used in the process, calculating the motion frequency of the stroke mover, comparing the motion frequency with the starting frequency, and if the starting frequency is not met, continuing the dragging of the next stroke; if the engine start-up request meets the requirement, the control system controls the engine to ignite and burn, and the start is finished.
3. The FPLG steady operation control method based on vibration acceleration signal according to claim 2, wherein:
when the target displacement and the movement frequency can not meet the starting condition, calculating the dragging force F required by the target displacement from the left dead center to the right dead centerRight sideAnd feeds back the power to the control system and controls the motor to provide a right dragging force FRight sideIf the right dead center position which can be reached by the rotor in the process does not meet the target displacement, dragging for the third time;
and if the position of the right side dead center meets the target displacement, calculating whether the moving frequency of the mover of the stroke meets the starting frequency, if not, dragging for the third time, and if so, controlling the engine to ignite and burn by the control system, and finishing the starting.
4. The FPLG steady operation control method based on the vibration acceleration signal according to claim 1, wherein the step S120 comprises:
calculating and describing the vibration displacement of IMEP according to the average indicated pressure and by combining the linear relation between the vibration displacement before the peak pressure after the combustion starting point and the in-cylinder pressure; and the average displacement of the IMEP can be described by combining the second differential relation of the vibration displacement and the vibration acceleration.
5. A FPLG steady operation control system based on vibration acceleration signals is characterized by comprising:
the starting module is used for calculating a target dragging force required by the mover to move to a target displacement according to the target displacement and the starting frequency which are required by the mover, and controlling the ignition starting of the engine according to a starting condition;
the average displacement calculation module is used for acquiring vibration acceleration signals of the started rotor in real time and calculating and describing the average displacement of the average indicated pressure in the cylinder; according to internal combustion engine principles, the average indicated pressure may be expressed as follows:
wherein, VhIndicating cylinderTotal volume, pi、pi-1Respectively representing in-cylinder pressures at i and i-1, Vi、Vi-1Indicates the cylinder volume at time i, i-1;
the vibration displacement before the peak pressure after the combustion starting point and the in-cylinder pressure are in a linear relation, and then the vibration displacement characteristic parameters describing IMEP are as follows:
wherein S ismeanRepresenting a characteristic parameter of vibration displacement, Si、Si-1Respectively representing the vibration displacement of the cylinder body at the time i and the time i-1;
combining the second order differential relationship between the vibrational displacement and the vibrational acceleration, the average displacement describing IMEP can be described as:
wherein S is1Representing the displacement, v, at the first moment of the vibration measurement period1Representing the speed at the first moment of the vibration measurement period, akRepresenting the vibration acceleration at the kth moment, wherein n is the total point number of the moment of the selected section of vibration acceleration, i, j, k is an element (1, 2.. multidot., n);
the target power generation amount calculating module is used for calculating the target power generation amount of one stroke according to the linear relation between the average displacement and the average indicating pressure and the linear relation between the average indicating pressure and the power generation amount;
and the control module is used for controlling the voltage of the generator terminal according to the target generated energy so as to control the output current to meet the power generation requirement and realize the stable operation of the FPLG.
6. A non-transitory computer-readable storage medium characterized in that: the non-transitory computer readable storage medium comprising instructions for performing the method of any of claims 1-4.
7. An electronic device, characterized in that: comprising the non-transitory computer-readable storage medium of claim 6; and one or more processors capable of executing the instructions of the non-transitory computer-readable storage medium.
8. An electronic device, characterized in that: the apparatus comprising means for performing the method of any one of claims 1-4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011140896.5A CN112267939B (en) | 2020-10-22 | 2020-10-22 | FPLG stable operation control method and system based on vibration acceleration signal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011140896.5A CN112267939B (en) | 2020-10-22 | 2020-10-22 | FPLG stable operation control method and system based on vibration acceleration signal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112267939A CN112267939A (en) | 2021-01-26 |
| CN112267939B true CN112267939B (en) | 2021-11-05 |
Family
ID=74341807
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011140896.5A Active CN112267939B (en) | 2020-10-22 | 2020-10-22 | FPLG stable operation control method and system based on vibration acceleration signal |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112267939B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113431680B (en) * | 2021-05-20 | 2022-05-13 | 北京化工大学 | Full-period acquisition and instantaneous speed calculation method of engine monitoring signals based on tooth pulse of tooth-lacking fluted disc |
| CN114909226B (en) * | 2022-05-31 | 2023-08-22 | 重庆长安汽车股份有限公司 | Method and system for controlling engine light-off working condition pumping and automobile |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107288751B (en) * | 2017-07-27 | 2019-09-10 | 吉林大学 | Free-piston engine piston trajectory control method |
| DE102018117066A1 (en) * | 2018-07-13 | 2020-01-16 | Simon Neukom | Method for operating a free piston linear generator |
| CN110529268B (en) * | 2019-09-20 | 2022-03-01 | 山东休普动力科技股份有限公司 | Method for stable operation of composite free piston linear generator |
| CN110608104B (en) * | 2019-09-20 | 2022-04-15 | 山东休普动力科技股份有限公司 | Control method for stabilizing top dead center position of free piston linear generator |
-
2020
- 2020-10-22 CN CN202011140896.5A patent/CN112267939B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112267939A (en) | 2021-01-26 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112267939B (en) | FPLG stable operation control method and system based on vibration acceleration signal | |
| Atkinson et al. | Numerical simulation of a two-stroke linear engine-alternator combination | |
| Feng et al. | Research on the intermediate process of a free-piston linear generator from cold start-up to stable operation: Numerical model and experimental results | |
| CN110529268B (en) | Method for stable operation of composite free piston linear generator | |
| US10202897B2 (en) | Systems and methods for transient control of a free-piston engine | |
| Wu et al. | Semi-analytical modelling of a hydraulic free-piston engine | |
| CN110608104B (en) | Control method for stabilizing top dead center position of free piston linear generator | |
| CN109653869B (en) | Two-stroke free piston power generation system and power generation method thereof | |
| Lin et al. | Thermodynamic simulation and prototype testing of a four-stroke free-piston engine | |
| Wu et al. | Experimental analysis on the operation process of opposed-piston free piston engine generator | |
| Lu et al. | A starting control strategy of single-cylinder two-stroke free-piston engine generator | |
| CN112228233B (en) | FPLG stable operation control method and system based on vibration speed signal | |
| Vu et al. | Piston motion control for a dual free piston linear generator: predictive-fuzzy logic control approach | |
| JP6015853B2 (en) | Control device and control method for internal combustion engine | |
| CN106194448B (en) | The control device of internal combustion engine | |
| CN109488471B (en) | Method for controlling stable operation process of free piston engine | |
| JP2011202621A (en) | Control device of internal combustion engine | |
| JP6102679B2 (en) | Engine control device | |
| CN112836290B (en) | Free piston linear motor matching optimization method based on system output | |
| CN115163296B (en) | System and method for improving combustion efficiency and operation stability of free piston internal combustion generator | |
| CN112761782B (en) | Free piston linear generator motion characteristic simulation analysis method and system | |
| CN112818520B (en) | Vibration signal-based FPLG control strategy simulation model construction method and system | |
| CN112324563B (en) | Double-winding free piston linear generator and control method | |
| CN112326256B (en) | Method and system for improving FPLG combustion thermal efficiency based on constant volume combustion | |
| CN103498733A (en) | Movement and control method for free piston internal combustion engine generator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20231213 Address after: Building on the west side of Building A1, No. 22 Zihe Avenue, Nanding Town, Zibo Economic Development Zone, Zibo City, Shandong Province, 255051 Patentee after: Shandong Zhongxuan Intelligent Technology Co.,Ltd. Address before: 252000 No.1 Hunan Road, Dongchangfu District, Liaocheng City, Shandong Province Patentee before: LIAOCHENG University |