CN117350072A - Method, system and medium for optimizing structural parameters of engine fuel injection system - Google Patents
Method, system and medium for optimizing structural parameters of engine fuel injection system Download PDFInfo
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- 239000000446 fuel Substances 0.000 title claims abstract description 72
- 238000002347 injection Methods 0.000 title claims abstract description 52
- 239000007924 injection Substances 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 47
- 238000013461 design Methods 0.000 claims abstract description 19
- 238000005457 optimization Methods 0.000 claims abstract description 8
- 239000007788 liquid Substances 0.000 claims abstract description 5
- 239000003990 capacitor Substances 0.000 claims description 99
- 239000003921 oil Substances 0.000 claims description 57
- 239000000295 fuel oil Substances 0.000 claims description 30
- 238000004590 computer program Methods 0.000 claims description 12
- 238000003860 storage Methods 0.000 claims description 6
- 238000004364 calculation method Methods 0.000 claims description 4
- 238000010276 construction Methods 0.000 claims description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 10
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- 238000011160 research Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 8
- 239000007789 gas Substances 0.000 description 8
- 230000010355 oscillation Effects 0.000 description 7
- 230000000694 effects Effects 0.000 description 6
- 238000004088 simulation Methods 0.000 description 6
- 239000002283 diesel fuel Substances 0.000 description 5
- 239000002737 fuel gas Substances 0.000 description 5
- 239000003345 natural gas Substances 0.000 description 5
- 230000006870 function Effects 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 230000001965 increasing effect Effects 0.000 description 3
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- 238000011161 development Methods 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 1
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- 239000003795 chemical substances by application Substances 0.000 description 1
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- 230000003287 optical effect Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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- G—PHYSICS
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- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
- G06F17/11—Complex mathematical operations for solving equations, e.g. nonlinear equations, general mathematical optimization problems
- G06F17/13—Differential equations
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
- G06F30/15—Vehicle, aircraft or watercraft design
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/10—Geometric CAD
- G06F30/17—Mechanical parametric or variational design
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
- G06F30/28—Design optimisation, verification or simulation using fluid dynamics, e.g. using Navier-Stokes equations or computational fluid dynamics [CFD]
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2111/00—Details relating to CAD techniques
- G06F2111/10—Numerical modelling
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
- G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
Abstract
The invention discloses a method, a system and a medium for optimizing structural parameters of an engine fuel injection system, which relate to the field of structural parameter optimization of the fuel injection system, establish an equivalent LC numerical model of a common rail pipe-oil inlet pipe-injector of a fuel hydraulic driving system based on a liquid electric modeling principle, and calculate system pressure fluctuation frequency of the common rail pipe-oil inlet pipe-injector under different structural parameters to determine optimal structural parameters; design parameters of the engine fuel injection system are determined based on the optimal structural parameters. By establishing an LC numerical model equivalent to the common rail pipe, the high-pressure oil pipe and the oil injector, the structural parameters of the hydraulic driving system are changed to match the structural parameters of the hydraulic driving system corresponding to the optimized hydraulic ram pressure fluctuation to be applied to the design parameters of the injection system, so that the influence of the pressure fluctuation on the overall performance of the engine is reduced or inhibited, and an optimization scheme is provided for the structural design of reducing the pressure fluctuation in engineering.
Description
Technical Field
The invention relates to the field of structural parameter optimization of fuel injection systems, in particular to a method, a system and a medium for optimizing structural parameters of a fuel injection system of a high-pressure direct injection natural gas engine based on a liquid-electricity modeling principle.
Background
The natural gas hydraulic control circuit, the diesel hydraulic control pipeline and the control cavity in the HPDI injector are mutually independent, and the oil return pipeline is connected. Diesel oil passes through the common rail pipe and the high-pressure oil pipe and then enters the natural gas hydraulic control loop and the diesel oil hydraulic control loop respectively. HPDI (high pressure direct injection) refers to injecting a small amount of diesel fuel as an ignition agent before top dead center of compression stroke to form flame, and injecting high pressure natural gas after ignition. However, both the injection and injection events cause the oil pressure within the injector itself to fluctuate, and the pressure fluctuations caused by the injection event can affect the injection event.
The pressure fluctuation characteristic research mainly establishes a high-pressure common rail system through one-dimensional simulation software, mainly researches the influence of a high-pressure fuel feed pump structure and operation parameters on the performance of the high-pressure common rail system from the aspect of structural design, establishes key structural parameters, and calculates the influence of key parameters such as plunger quality, plunger diameter, plunger stroke, plunger occasional sealing diameter and the like of the high-pressure fuel feed pump on the pressure fluctuation of the HPDI injector in a simulation manner. And then, by building a test bed, comparing experimental data with simulation results, verifying the accuracy of a model, and analyzing the influence mechanism of each structural parameter and operation parameter of the system on the pressure fluctuation of the common rail pipe by taking the model as a stand point. The existing ejector is difficult to refit and high in cost, and in the actual research process of the existing pressure fluctuation characteristic research, because of limiting conditions such as experimental conditions and test means, only the speed and pressure of individual key positions of the high-pressure oil circuit can be simply measured and analyzed, and the real flow condition inside the high-pressure oil circuit can not be obtained, so that the simulation means are adopted to conduct the research of the pressure fluctuation generation and propagation mechanism of the high-pressure oil circuit, but the one-dimensional calculation can only obtain the overall performance of the system, and the real flow condition inside the oil circuit can not be reflected. The researches are mainly focused on the influence law of common rail pipe structural parameters such as length-diameter ratio, common rail pipe volume and the like on rail pressure fluctuation, and are mainly focused on one-dimensional simulation, so that the researches on the internal fuel flow and internal pressure wave generation and propagation processes of the common rail system volume cavity are relatively less, and the design and development cycle side length and the cost of the injector are increased by an experimental and simulation method.
Disclosure of Invention
The invention aims to provide a method, a system and a medium for optimizing structural parameters of an engine fuel injection system, which solve the problem of reducing or inhibiting the influence of pressure fluctuation on the performance of an HPDI (high pressure direct injection) injector.
In order to achieve the above object, the present invention provides the following solutions:
a method of optimizing structural parameters of an engine fuel injection system, the method comprising:
establishing an equivalent LC numerical model of a common rail pipe-oil inlet pipe-injector of the fuel oil hydraulic driving system based on a liquid electric modeling principle;
calculating the system pressure fluctuation frequency of the common rail pipe-oil inlet pipe-injector under different structural parameters based on the equivalent LC numerical model;
determining an optimal structural parameter based on the system pressure fluctuation frequency; the optimal structural parameters are the lowest structural parameters in the system pressure fluctuation frequency corresponding to each structural parameter;
design parameters of an engine fuel injection system are determined based on the optimal structural parameters.
Optionally, the equivalent LC numerical model includes: the first hydraulic capacitor of the fuel common rail, the second hydraulic capacitor of the fuel inlet pipe, the third hydraulic capacitor of the fuel hydraulic control pipeline, the fourth hydraulic capacitor of the fuel hydraulic control pipeline, the fifth hydraulic capacitor of the fuel hydraulic control cavity and the sixth hydraulic capacitor of the fuel hydraulic control cavity;
one end of the first hydraulic capacitor is grounded, the other end of the first hydraulic capacitor is connected with one end of the first hydraulic inductor, the other end of the first hydraulic inductor is connected with one end of the second hydraulic capacitor, and the other end of the second hydraulic capacitor is grounded;
the other end of the first hydraulic inductor is also connected with one end of the third hydraulic capacitor and one end of the second hydraulic inductor through the first switch respectively; the other end of the third hydraulic capacitor is grounded, the other end of the second hydraulic inductor is connected with one end of the fifth hydraulic capacitor, and the other end of the fifth hydraulic capacitor is grounded; the first switch is a fuel oil hydraulic control pipeline change-over switch;
the other end of the first hydraulic inductor is also connected with one end of the fourth hydraulic capacitor and one end of the third hydraulic inductor through the second switch respectively; the other end of the fourth hydraulic capacitor is grounded, the other end of the third hydraulic inductor is connected with one end of the sixth hydraulic capacitor, and the other end of the sixth hydraulic capacitor is grounded; the second switch is a gas hydraulic control pipeline change-over switch;
in the equivalent LC numerical model, the common connection point between the first hydraulic capacitor and the first hydraulic inductor is the fuel oil common rail pressure; the common connection point of the first hydraulic inductor and the second hydraulic capacitor is the pressure of an oil inlet pipe; the common connection point of the third hydraulic capacitor and the second hydraulic inductor is the pressure in the fuel control pipeline; the common connection point of the second hydraulic inductor and the fifth hydraulic capacitor is the pressure in the fuel control cavity; the common connection point of the fourth hydraulic capacitor and the third hydraulic inductor is the pressure in the gas control pipeline; the common connection point of the third hydraulic inductor and the sixth hydraulic capacitor is the pressure in the gas control cavity;
in the equivalent LC numerical model, the direction of mass flow in an oil inlet pipe points to a second end from a first end of the first hydraulic inductor; the first end of the first inductor is one end close to the first hydraulic capacitor, and the first end of the first inductor is one end close to the second hydraulic capacitor;
the direction of the mass flow in the fuel oil hydraulic control pipeline points to the second end from the first end of the second hydraulic inductor; the first end of the second inductor is one end close to the third hydraulic capacitor, and the first end of the second inductor is one end close to the fifth hydraulic capacitor;
the direction of the mass flow in the gas hydraulic control pipeline points to the second end from the first end of the third hydraulic inductor; the first end of the third inductor is one end close to the fourth hydraulic capacitor, and the first end of the third inductor is one end close to the sixth hydraulic capacitor.
Optionally, calculating the system pressure fluctuation frequency of the common rail pipe-oil inlet pipe-injector under different structural parameters based on the equivalent LC numerical model specifically includes:
establishing a hydraulic capacitance equation and a hydraulic inductance equation based on the equivalent LC numerical model;
and solving the system pressure fluctuation frequency based on the hydraulic capacitance equation and the inductance equation.
Optionally, in the fuel injection process, the rail pressure of the fuel common rail is equal to the pressure at the fuel inlet pipe, and the hydraulic capacitance equation includes:
the hydraulic inductance equation includes:
wherein C is 0 A hydraulic capacitor for the fuel common rail; c (C) 1 A hydraulic capacitor for the oil inlet pipe; c (C) 2 A hydraulic capacitor which is a fuel oil hydraulic control pipeline; c (C) 4 A hydraulic capacitor which is a fuel oil hydraulic control cavity; l (L) 0 A hydraulic inductance for the oil inlet pipe; l (L) 1 The hydraulic inductance is used for the hydraulic control pipeline of the fuel oil; l (L) 0 The first hydraulic inductor is used as an oil inlet pipe; l (L) 1 Hydraulic control pipeline for fuel oilIs arranged on the first hydraulic inductor; g 0 G for mass flow in the oil inlet pipe 1 The mass flow in the fuel oil hydraulic control pipeline is controlled; p is p 0 Is the rail pressure of the fuel common rail, p 2 The pressure in the fuel oil control pipeline is; p is p 4 The pressure in the cavity is controlled for the fuel oil.
Optionally, in the oil injection process, the expression of the system pressure fluctuation frequency is:
wherein omega 0 Is the frequency associated with a system comprising a fuel common rail, an inlet pipe and a hydraulic control line; omega 1 Is the frequency related to the system comprising an oil inlet pipe, a hydraulic control pipeline and a hydraulic control cavity.
The invention also provides a system for optimizing structural parameters of an engine fuel injection system, which comprises:
the equivalent model construction module is used for establishing an equivalent LC numerical model of a common rail pipe-oil inlet pipe-injector of the fuel oil hydraulic driving system based on the electrohydraulic modeling principle;
the pressure fluctuation frequency calculation module is used for calculating the system pressure fluctuation frequency of the common rail pipe-oil inlet pipe-injector under different structural parameters based on the equivalent LC numerical model;
the structural parameter optimizing module is used for determining an optimal structural parameter based on the system pressure fluctuation frequency; the optimal structural parameters are the lowest structural parameters in the system pressure fluctuation frequency corresponding to each structural parameter;
a system design module for determining design parameters of the engine fuel injection system based on the optimal structural parameters.
The invention also provides a computer readable storage medium storing a computer program which when executed by a processor implements the method for optimizing structural parameters of an engine fuel injection system.
According to the specific embodiment provided by the invention, the invention discloses the following technical effects:
the invention provides a method, a system and a medium for optimizing structural parameters of an engine fuel injection system, which change structural parameters of a hydraulic driving system by establishing an LC numerical model equivalent to a common rail pipe, a high-pressure oil pipe and an oil injector of the diesel hydraulic driving system, thereby changing the oscillation form of water hammer pressure fluctuation, matching the structural parameters of the hydraulic driving system corresponding to the optimized water hammer pressure fluctuation and applying the structural parameters to the injection system, achieving the effect of reducing or inhibiting the pressure fluctuation on the integral performance of the engine, and providing an optimization scheme for the structural design of reducing the pressure fluctuation in engineering.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for optimizing structural parameters of an engine fuel injection system according to embodiment 1 of the present invention;
FIG. 2 is a schematic diagram of optimizing structural parameters of an engine fuel injection system according to embodiment 1 of the present invention;
FIG. 3 is a block diagram of the internal hydraulic circuit of an HPDI injector provided in embodiment 1 of the present invention;
FIG. 4 is a schematic view of an LC numerical model of an HPDI injector provided in example 1 of the present invention;
FIG. 5 is a graph comparing experimental and simulated water hammer pressure fluctuation curves provided in example 1 of the present invention;
FIG. 6 is a graph showing the effect of pressure fluctuation at the inlet of diesel fuel for different lengths of high-pressure oil pipe according to example 1 of the present invention;
fig. 7 is a graph showing the effect of pressure fluctuation of the diesel fuel inlet on the volume of the common rail chamber according to example 1 of the present invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention aims to provide a method, a system and a medium for optimizing structural parameters of an engine fuel injection system, which solve the problem of reducing or inhibiting the influence of pressure fluctuation on the performance of an HPDI (high pressure direct injection) injector.
In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.
Example 1
As shown in fig. 1 and 2, the present embodiment provides a method for optimizing structural parameters of a fuel injection system of an engine, the method including:
s1: and establishing an equivalent LC numerical model of the common rail pipe-oil inlet pipe-injector of the fuel oil hydraulic driving system based on the electrohydraulic modeling principle.
The structural parameters of the actual system, including the diameter and length of the high-pressure oil pipe, the volume of the oil rail and the like, which can be obtained are obtained and used as the input quantity of an LC numerical model based on the electrohydraulic modeling principle, and an equivalent model is constructed based on the parameters.
The pressure fluctuations caused by the injection process affect the injection process, and the pressure fluctuations here are of a form similar to a second-order LC oscillating circuit. The construction of the model includes the rails, oil feed pipe and injectors, which can be considered to consist of hydraulic capacitance and inductance. Since the main purpose of building this model is to reduce or dampen pressure fluctuations, the frequency of which is hardly affected by hydraulic resistance, the hydraulic resistance associated with distributed viscous friction losses can be neglected.
Wherein, as shown in fig. 3 and 4, the equivalent LC numerical model includes: first hydraulic capacitor C of fuel common rail 0 Second hydraulic capacitor C of oil inlet pipe (high-pressure oil pipe) 1 And burningThird hydraulic capacitor C of oil (e.g. diesel) hydraulic control pipeline 2 Fourth hydraulic capacitor C of fuel gas (such as natural gas) hydraulic control pipeline 3 Fifth hydraulic capacitor C of fuel oil hydraulic control cavity 4 Sixth hydraulic capacitor C of fuel gas hydraulic control cavity 5 。
One end of the first hydraulic capacitor is grounded, the other end of the first hydraulic capacitor is connected with one end of the first hydraulic inductor, the other end of the first hydraulic inductor is connected with one end of the second hydraulic capacitor, and the other end of the second hydraulic capacitor is grounded.
The other end of the first hydraulic inductor is also connected with one end of the third hydraulic capacitor and one end of the second hydraulic inductor through the first switch respectively; the other end of the third hydraulic capacitor is grounded, the other end of the second hydraulic inductor is connected with one end of the fifth hydraulic capacitor, and the other end of the fifth hydraulic capacitor is grounded; the first switch S 1 The switch is used for controlling the pipeline to switch for the fuel oil hydraulic pressure.
The other end of the first hydraulic inductor is also connected with one end of the fourth hydraulic capacitor and one end of the third hydraulic inductor through the second switch respectively; the other end of the fourth hydraulic capacitor is grounded, the other end of the third hydraulic inductor is connected with one end of the sixth hydraulic capacitor, and the other end of the sixth hydraulic capacitor is grounded; the second switch S 2 Is a gas hydraulic control pipeline change-over switch. Switch S 1 And S is 2 The power failure time of the fuel injection valve is independently controlled to realize different injection strategies, namely when fuel injection is needed, the first switch is connected, fuel oil is introduced into the common rail and the high-pressure oil pipe, and when fuel gas is needed to be injected, the second switch is connected, and fuel gas is circulated into the common rail and the high-pressure oil pipe.
In the equivalent LC numerical model, the common connection point between the first hydraulic capacitor and the first hydraulic inductor is the fuel oil common rail pressure p 0 The method comprises the steps of carrying out a first treatment on the surface of the The common connection point of the first hydraulic inductor and the second hydraulic capacitor is the pressure p at the oil inlet pipe 1 The method comprises the steps of carrying out a first treatment on the surface of the The common connection point of the third hydraulic capacitor and the second hydraulic inductor is the pressure in the fuel control pipelinep 2 The method comprises the steps of carrying out a first treatment on the surface of the The common connection point of the second hydraulic inductor and the fifth hydraulic capacitor is the pressure p in the fuel control cavity 4 The method comprises the steps of carrying out a first treatment on the surface of the The common connection point of the fourth hydraulic capacitor and the third hydraulic inductor is the pressure p in the gas control pipeline 3 The method comprises the steps of carrying out a first treatment on the surface of the The common connection point of the third hydraulic inductor and the sixth hydraulic capacitor is the pressure p in the gas control cavity 5 。
In the equivalent LC numerical model, the mass flow G in the oil inlet pipe 0 From a first end of the first hydraulic inductor to a second end; the first end of the first inductor is one end close to the first hydraulic capacitor, and the first end of the first inductor is one end close to the second hydraulic capacitor.
Mass flow rate G in fuel hydraulic control line 1 From a first end of the second hydraulic inductor to a second end; the first end of the second inductor is one end close to the third hydraulic capacitor, and the first end of the second inductor is one end close to the fifth hydraulic capacitor.
Mass flow rate G in gas-fired hydraulic control line 2 From a first end of the third hydraulic inductor to a second end; the first end of the third inductor is one end close to the fourth hydraulic capacitor, and the first end of the third inductor is one end close to the sixth hydraulic capacitor.
S2: and calculating the system pressure fluctuation frequency of the common rail pipe-oil inlet pipe-injector under different structural parameters based on the equivalent LC numerical model. The method specifically comprises the following steps:
establishing a hydraulic capacitance equation and a hydraulic inductance equation based on the equivalent LC numerical model;
and solving the system pressure fluctuation frequency based on the hydraulic capacitance equation and the inductance equation.
More specifically, the hydraulic capacitance and inductance are defined as
Wherein V is the volume of the pressure accumulation cavity, a is the sound velocity of fuel oil, l is the length of the pipeline, A is the cross-sectional area of the pipeline, and l is the length of the pipeline.
In the oil injection process, p 1 ＝p 2 。
The equation for capacitor discharge is:
the inductance equation is:
the inductance equation is derived and then is combined with the capacitance equation to obtain an equation set with two degrees of freedom, and the unknown quantity is the mass flow of fluid:
this system of equations can be represented in matrix form:
wherein,
the frequency can be represented by matrix L -1 The characteristic value of K is obtained:
can also be written as
Wherein omega is 0 Is the frequency, omega, associated with a system comprising a diesel common rail, a high-pressure oil line and a hydraulic control line (fuel) 1 Is the frequency associated with a system comprising a high pressure oil line, a hydraulic control line (fuel), a hydraulic control chamber (fuel).
The obtained pressure fluctuation frequency of the whole system is
In the process of spraying fuel gas, p 1 ＝p 3 The method comprises the steps of carrying out a first treatment on the surface of the In the process of calculating the pressure fluctuation frequency, only the parameter C in the gas passage is needed to be utilized 3 And C 5 Replacement C 2 And C 4 The method comprises the steps of carrying out a first treatment on the surface of the By L 1 Replacement of L 2 。
S3: determining an optimal structural parameter based on the system pressure fluctuation frequency; and the optimal structural parameters are the lowest structural parameters in the system pressure fluctuation frequency corresponding to each structural parameter.
According to the measured value, an equivalent model is built, so that the result of the model is similar to the actually measured pressure fluctuation, the system parameters can be changed through the equivalent model, and whether the system is capacitive or inductive can be analyzed, so that the performance of the system is improved, and the purpose of reducing the amplitude and the frequency of the pressure fluctuation is achieved.
S4: design parameters of an engine fuel injection system are determined based on the optimal structural parameters.
The following is the actual simulation result of the scheme:
the fuel inlet pressure fluctuation of 25MPa and the fuel injection pulse width of 0.5ms is simulated, and the water hammer pressure fluctuation form is shown in figure 5. The experimental water hammer pressure fluctuation is coincident with the simulated water hammer pressure fluctuation, the same trend is provided on the period and the amplitude, and the curve of the water hammer pressure fluctuation is in an oscillation attenuation form.
As shown in fig. 6, increasing the length of the high pressure tubing may increase the sensitivity of the system. The effect of high pressure tubing length on diesel inlet pressure fluctuations is shown. D (D) 0 For the original high-pressure oil pipe length D 1 Ratio D 0 Length of 30cm, D 2 Ratio D 0 And 50cm long. As can be seen from fig. 6, as the high-pressure oil pipe increases, the oscillation amplitude increases, the oscillation period increases, and the propagation distance of the pressure wave increases, as compared with the original system. Therefore, the scheme of the invention can also research the propagation mechanism of the high-pressure oil pipe by establishing an equivalent LC numerical model.
Increasing the common rail plenum volume increases the system capacity, and the effect of the common rail plenum volume on the diesel inlet pressure fluctuations is shown in fig. 7. V (V) 0 Is the volume of the original common rail cavity, V 1 Ratio V 0 Is 3cm larger 3 ，V 2 Ratio V 0 5cm larger 3 . As can be seen from the figure, as the volume of the common rail cavity increases, the oscillation amplitude decreases, the oscillation period decreases, and the frequency of the pressure wave decreases as compared with the original system.
In the embodiment, through establishing the equivalent LC numerical model of the common rail pipe, the high-pressure oil pipe and the oil injector of the diesel hydraulic driving system, the structural parameters of the hydraulic driving system are changed, so that the oscillation form of the water hammer pressure fluctuation is changed, the structural parameters of the hydraulic driving system corresponding to the optimized water hammer pressure fluctuation are matched and applied to the design parameters of the injection system, the influence of the pressure fluctuation on the overall performance of the engine is reduced or inhibited, and an optimization scheme is provided for the structural design of reducing the pressure fluctuation in engineering. (1) Compared with the traditional pressure fluctuation characteristic research method, the invention establishes a new model based on the liquid electric modeling principle, and realizes the establishment of an equivalent LC numerical model by utilizing the liquid electric modeling principle. (2) Structural parameters of the fuel injection system of the engine are optimized based on the equivalent LC numerical model, so that the development period of the optimal design of the injector is shortened, and the cost is saved. (3) Through the establishment of an equivalent model, the structural parameters of the hydraulic driving system are changed, and the structural parameters of the system corresponding to the optimized water hammer pressure fluctuation are selected and applied to the design parameters of the injection system.
Example 2
The present embodiment provides an engine fuel injection system structural parameter optimization system, the system comprising:
and the equivalent model construction module is used for establishing an equivalent LC numerical model of the common rail pipe-oil inlet pipe-injector of the fuel oil hydraulic driving system based on the electrohydraulic modeling principle.
And the pressure fluctuation frequency calculation module is used for calculating the system pressure fluctuation frequency of the common rail pipe-oil inlet pipe-injector under different structural parameters based on the equivalent LC numerical model.
The structural parameter optimizing module is used for determining an optimal structural parameter based on the system pressure fluctuation frequency; and the optimal structural parameters are the lowest structural parameters in the system pressure fluctuation frequency corresponding to each structural parameter.
A system design module for determining design parameters of the engine fuel injection system based on the optimal structural parameters.
Example 3
The present embodiment provides a computer-readable storage medium storing a computer program which, when executed by a processor, implements the engine fuel injection system structural parameter optimization method of embodiment 1.
In addition, the present embodiment also provides an electronic device, including a memory and a processor, where the memory is configured to store a computer program, and the processor is configured to execute the computer program to cause the electronic device to execute the method for optimizing the structural parameters of the fuel injection system of the engine of embodiment 1.
Alternatively, the electronic device may be a server.
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 flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations 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.
In this specification, each embodiment is mainly described in the specification as a difference from other embodiments, and the same similar parts between the embodiments are referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section.
The principles and embodiments of the present invention have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the methods of the present invention and the core ideas thereof; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (7)
1. A method for optimizing structural parameters of an engine fuel injection system, the method comprising:
establishing an equivalent LC numerical model of a common rail pipe-oil inlet pipe-injector of the fuel oil hydraulic driving system based on a liquid electric modeling principle;
calculating the system pressure fluctuation frequency of the common rail pipe-oil inlet pipe-injector under different structural parameters based on the equivalent LC numerical model;
determining an optimal structural parameter based on the system pressure fluctuation frequency; the optimal structural parameters are the lowest structural parameters in the system pressure fluctuation frequency corresponding to each structural parameter;
design parameters of an engine fuel injection system are determined based on the optimal structural parameters.
2. The method of claim 1, wherein the equivalent LC numerical model comprises: the first hydraulic capacitor of the fuel common rail, the second hydraulic capacitor of the fuel inlet pipe, the third hydraulic capacitor of the fuel hydraulic control pipeline, the fourth hydraulic capacitor of the fuel hydraulic control pipeline, the fifth hydraulic capacitor of the fuel hydraulic control cavity and the sixth hydraulic capacitor of the fuel hydraulic control cavity;
one end of the first hydraulic capacitor is grounded, the other end of the first hydraulic capacitor is connected with one end of the first hydraulic inductor, the other end of the first hydraulic inductor is connected with one end of the second hydraulic capacitor, and the other end of the second hydraulic capacitor is grounded;
the other end of the first hydraulic inductor is also connected with one end of the third hydraulic capacitor and one end of the second hydraulic inductor through the first switch respectively; the other end of the third hydraulic capacitor is grounded, the other end of the second hydraulic inductor is connected with one end of the fifth hydraulic capacitor, and the other end of the fifth hydraulic capacitor is grounded; the first switch is a fuel oil hydraulic control pipeline change-over switch;
the other end of the first hydraulic inductor is also connected with one end of the fourth hydraulic capacitor and one end of the third hydraulic inductor through the second switch respectively; the other end of the fourth hydraulic capacitor is grounded, the other end of the third hydraulic inductor is connected with one end of the sixth hydraulic capacitor, and the other end of the sixth hydraulic capacitor is grounded; the second switch is a gas hydraulic control pipeline change-over switch;
in the equivalent LC numerical model, the common connection point between the first hydraulic capacitor and the first hydraulic inductor is the fuel oil common rail pressure; the common connection point of the first hydraulic inductor and the second hydraulic capacitor is the pressure of an oil inlet pipe; the common connection point of the third hydraulic capacitor and the second hydraulic inductor is the pressure in the fuel control pipeline; the common connection point of the second hydraulic inductor and the fifth hydraulic capacitor is the pressure in the fuel control cavity; the common connection point of the fourth hydraulic capacitor and the third hydraulic inductor is the pressure in the gas control pipeline; the common connection point of the third hydraulic inductor and the sixth hydraulic capacitor is the pressure in the gas control cavity;
in the equivalent LC numerical model, the direction of mass flow in an oil inlet pipe points to a second end from a first end of the first hydraulic inductor; the first end of the first inductor is one end close to the first hydraulic capacitor, and the first end of the first inductor is one end close to the second hydraulic capacitor;
the direction of the mass flow in the fuel oil hydraulic control pipeline points to the second end from the first end of the second hydraulic inductor; the first end of the second inductor is one end close to the third hydraulic capacitor, and the first end of the second inductor is one end close to the fifth hydraulic capacitor;
the direction of the mass flow in the gas hydraulic control pipeline points to the second end from the first end of the third hydraulic inductor; the first end of the third inductor is one end close to the fourth hydraulic capacitor, and the first end of the third inductor is one end close to the sixth hydraulic capacitor.
3. The method according to claim 2, characterized in that calculating the system pressure fluctuation frequency of the common rail pipe-oil inlet pipe-injector under different structural parameters based on the equivalent LC numerical model comprises:
establishing a hydraulic capacitance equation and a hydraulic inductance equation based on the equivalent LC numerical model;
and solving the system pressure fluctuation frequency based on the hydraulic capacitance equation and the inductance equation.
4. A method according to claim 3, wherein during injection, the fuel rail pressure is equal to the pressure at the inlet line, and the hydraulic capacitance equation comprises:
the hydraulic inductance equation includes:
wherein C is 0 A hydraulic capacitor for the fuel common rail; c (C) 1 A hydraulic capacitor for the oil inlet pipe; c (C) 2 A hydraulic capacitor which is a fuel oil hydraulic control pipeline; c (C) 4 A hydraulic capacitor which is a fuel oil hydraulic control cavity; l (L) 0 A hydraulic inductance for the oil inlet pipe; l (L) 1 The hydraulic inductance is used for the hydraulic control pipeline of the fuel oil; l (L) 0 The first hydraulic inductor is used as an oil inlet pipe; l (L) 1 The second hydraulic inductor is a fuel oil hydraulic control pipeline; g 0 G for mass flow in the oil inlet pipe 1 The mass flow in the fuel oil hydraulic control pipeline is controlled; p is p 0 Is the rail pressure of the fuel common rail, p 2 The pressure in the fuel oil control pipeline is; p is p 4 The pressure in the cavity is controlled for the fuel oil.
5. The method of claim 4, wherein the expression of the system pressure fluctuation frequency during fuel injection is:
wherein omega 0 Is the frequency associated with a system comprising a fuel common rail, an inlet pipe and a hydraulic control line; omega 1 Is the frequency related to the system comprising an oil inlet pipe, a hydraulic control pipeline and a hydraulic control cavity.
6. An engine fuel injection system structural parameter optimization system, the system comprising:
the equivalent model construction module is used for establishing an equivalent LC numerical model of a common rail pipe-oil inlet pipe-injector of the fuel oil hydraulic driving system based on the electrohydraulic modeling principle;
the pressure fluctuation frequency calculation module is used for calculating the system pressure fluctuation frequency of the common rail pipe-oil inlet pipe-injector under different structural parameters based on the equivalent LC numerical model;
the structural parameter optimizing module is used for determining an optimal structural parameter based on the system pressure fluctuation frequency; the optimal structural parameters are the lowest structural parameters in the system pressure fluctuation frequency corresponding to each structural parameter;
a system design module for determining design parameters of the engine fuel injection system based on the optimal structural parameters.
7. A computer-readable storage medium storing a computer program, which when executed by a processor implements the method for optimizing structural parameters of an engine fuel injection system according to any one of claims 1 to 5.
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