KR101306526B1 - Method for optimizing a injection nozzle for an internal combustion engine - Google Patents

Abstract

The present invention provides a method for optimizing an injection nozzle for an internal combustion engine, wherein the injection nozzle is axially movable against the closing pressure in the nozzle body 1 and the blind hole 2 of the nozzle body 1. The nozzle needle (3) has a valve sealing surface (4) at the combustion chamber side end surface, the valve sealing surface for controlling the flow cross section to one or more injection holes (5) directed into the combustion chamber of the internal combustion engine. A method of optimizing an injection nozzle for an internal combustion engine, which interacts with the valve seat face 6 of the nozzle body 1. According to the present invention, when arbitrarily selecting and using independent parameters for the geometrical specification of the spray nozzle, a mathematical method in the form of Particle Swarm Optimization (PSO) is used, and the criteria determined to be optimal are the structural design of the spray nozzle. Used for

Injection nozzle, optimizer, nozzle body, nozzle needle, valve sealing surface, valve seat surface.

Description

Optimization method of injection nozzle for internal combustion engine {METHOD FOR OPTIMIZING A INJECTION NOZZLE FOR AN INTERNAL COMBUSTION ENGINE}

1 is a cross sectional view of an injection nozzle, ie an orifice nozzle, optimized according to the present invention;

FIG. 2 is a cross-sectional view of another orifice nozzle optimized according to the invention with a plurality of round rows, here two rows of nozzles, in a nozzle cone; FIG.

Description of the Related Art [0002]

1: nozzle body 2: blind hole

3: nozzle needle 4: valve sealing surface

5: nozzle 6: valve seat surface

7: Nozzle Cone D _L : Nozzle Orifice Diameter

D _e : Blind hole diameter D _a : Lower needle seat diameter

κ: nozzle angle h: nozzle needle stroke

σ: sheet angle α: nozzle needle peak angle

ε: blind hole angle hs: blind hole height

hsp: injection point n: number of nozzle orifices

The present invention relates to a method for optimizing an injection nozzle for an internal combustion engine according to the preamble of claim 1.

The spray nozzle comprises, as is known, a nozzle needle and a nozzle needle movable axially against closing pressure in the blind hole of the nozzle body, the nozzle needle having a valve sealing surface at the combustion chamber side end face. The valve sealing surface interacts with the valve seat surface of the nozzle body to control the flow cross section to one or more injection holes directed into the combustion chamber of the internal combustion engine. The injection nozzle is assembled in the nozzle support, and the injection pipe is connected to the upper end of the nozzle support as is known. The fuel acts on the inclined shoulder of the nozzle needle in a pressure chamber inside the nozzle body and generally opens the nozzle needle against the closing pressure caused by hydraulic or spring force.

A typical injection nozzle is a so-called orifice nozzle, for example as known from DE 198 41 192 A1, and is preferably assembled in a direct injection engine. An orifice nozzle having a hole in the form of a blind hole in the nozzle body is manufactured to have 12 or more holes in one nozzle cone. The final design of the orifice nozzle is usually determined in engine testing. For example, different nozzle variants should be studied in terms of orifice number, hole diameter, hole length, angle between holes and the angle of the hole relative to the cylinder axis, its effect on the output, specific fuel consumption and the release of harmful substances.

The design of the injection nozzle has a decisive influence on the combustion of the engine. For orifice nozzles in the design of injection jets, in particular the number, diameter, position and geometry of the nozzle orifices and the high pressure in the blind holes are important. The emissions and fuel consumption of hydrocarbons (HC) and particles (eg carbon black) increase, in particular with increasing volume of blind holes. It is also known that if the blind hole volume is too large, it will increase the contamination of the engine lubricant and increase the wear of the cylinder passages.

In addition, the spray nozzles are subjected to high loads mechanically, thermally and hydraulically. Thus, for functional requirements in, for example, nozzle cones and needle seats, the provisions for the structure with respect to the part strength must be observed.

Mathematical methods for the design of injection valves are already known, in which the geometrical specifications comprise a system of the form of a target function f (x) from the variable chamber, for example from the above mentioned parameters, the target function values being a number of Iteratively determined by the calculation step. In each calculation step, the evolution of the probability values based on the target function f (x) and the stochastic differential equation is calculated. The optimal target function value and associated parameters determined by this numerical method are used in the design of the spray nozzle.

Because the steps described above are very complex, this sequential approach often does not serve the purpose.

It is an object of the present invention to provide a method for optimizing an injection nozzle for an internal combustion engine, which has an optimized configuration with respect to at least a reduction in the emission of harmful substances, an improvement in wear characteristics and a reduction in fuel consumption.

This subject is solved by the optimization method of the injection nozzle for internal combustion engines of Claim 1.

The present invention provides an entirely new method for optimizing the spray nozzle, which can optimize all types of spray nozzles with respect to their respective requirements and boundary conditions.

In the embodiment, in particular, an orifice nozzle having a blind hole having one row of nozzles (FIG. 1) or a plurality of rows of nozzles (FIG. 2) offset and arranged up and down is contemplated.

The algorithm implemented is a multi-criterion version of the Particle Swarm Optimization algorithm developed by the Applicant. The particle group optimization algorithm is a kind of nature-analog stochastic optimization method derived from artificial intelligence. The algorithm is based on a population of particles (a set of parameters as possible solutions) that interact with each other in search space when moving like flock (J. Kennedy, R. Eberhart: Particle Swarm Optimization. Proc. IEEE Int. Conf.on Neural Networks, 1995, pages 1942-1948).

The purpose of particle group optimization (PSO) is generally to find the optimal test function, the target function f (x). The target function may be a maximum or minimum value depending on the definition. In general, however, rather than any local optimal function, as in the numerical method described above, one should find the entire optimal test space, i.e. the overall optimal function of the solution space.

Since the parameters (particles) of the PSO are distributed throughout the entire solution space probabilistically and / or as defined at the beginning of the calculation, they have corresponding positions in the variable space. Particles are assigned a stochastic velocity vector and / or a predetermined velocity vector for initialization.

In each different step of the optimization algorithm, each particle is oriented, in particular, under the position of the neighboring particle and its unique previous optimal position. From the individual optimal solutions for each individual particle, the optimal solution of the particle group is selected by comparison operation. Particle groups tend to be directed towards particles that are optimally placed in their entirety.

The orientation of the particles in the solution space is n-dimensional according to the target function f (x) of the reference value / independent parameter / unknown.

The goal function may be written such that a plurality of goal values with unique weights are integrated. In this case, the target function is called a quality function. The target value corresponds to a specific mathematically detectable requirement, such as a blind hole volume which is minimized in the spray nozzle, which is functionally related to the geometric parameters.

The optimization algorithm has been found to be very effective because it is very fast and purposeful.

Another advantage is that particle group optimization can be applied to almost arbitrary and self-discontinuous functions, because they do not use derivatives. In other words, particle population optimization is very robust.

In summary, PSO is a robust and fast optimization method that can find the overall optimal function in almost any mathematical multidimensional function. By writing a quality function with weighted target values, a multi-criteria approach can be pursued.

The algorithm needs a set of settings that affect its characteristics. These settings are determined based on your experience so far.

Preferred embodiments of the invention are presented in the dependent claims and in the embodiments which follow. Although an embodiment of the present invention will be described with reference to the drawings, the present invention is not limited to this embodiment.

The invention comprises a nozzle body (1) and a nozzle needle (3) which is axially movable against the closing pressure in the blind hole (2) of the nozzle body (1), the nozzle needle (3) A valve seal face 4 is provided on the combustion chamber side end face, which valve face 6 of the nozzle body 1 controls the flow cross section to one or more injection ports 5 which are directed into the combustion chamber of the internal combustion engine. It relates to a method for optimizing the injection nozzle for the internal combustion engine that will interact with. Particle Swarm Optimization (PSO) type mathematical method is used when arbitrarily selecting independent parameters for the geometrical specification of the nozzle, and criteria determined to be optimal are used in the structural design of the spray nozzle.

In particular, the optimization of the PSO method preferably includes the following steps.

Determining predetermined boundary conditions (nozzle type and nozzle size) for geometric specifications such as, for example, the required nozzle flow rate and the pressure stage of the nozzle.

Technical requirements in the form of target values of the target function f (x) according to any number of independent parameters such as, for example, the maximum pressure in the holes (blind holes) of the nozzle body, the volume of the blind holes or the minimum nozzle needle seat angle (optimization). Detecting a value).

-Deriving independent parameters (degrees of freedom) of technical requirements from the definition of target values, for example, nozzle needle seat angle, lower nozzle needle seat diameter, nozzle peak angle, nozzle angle or nozzle needle stroke.

Determining a parameter limit in the form of a range of values.

Mathematically weighting the target value of the technical requirement in a quality function.

The quality function is given from a mathematical formula of requirements such as geometry, hydraulic pressure, mechanics, and the like.

1 shows a first embodiment of the method according to the invention, wherein the spray nozzle to be optimized is an orifice nozzle, which nozzle is axially against the closing pressure in the blind hole 2 of the nozzle body 1. And a nozzle cone (7) for closing the blind hole (2) with respect to the combustion chamber, the nozzle needle (3) being movably guided to the combustion chamber, the nozzle needle having a conical valve sealing surface (4) at the combustion chamber side end. This valve sealing surface interacts with the conical sealing seat surface 6 of the blind hole 2 at the end which is closed against the inside with a collar, and the plurality of injection holes 5 of the nozzle cone 7 are internal combustion engines. Extend into the combustion chamber.

1 and 2, the following facts become clear.

-As a certain boundary condition, those representing limitations relating to nozzle type, nozzle size and other uses can be presented and can be freely predetermined.

As technical requirements, a) the maximum pressure in the blind hole (thereby forming an optimum mixture), b) the minimum blind hole volume (thereby reducing carbon black and HC emissions and reducing fuel consumption), c) (required strength Minimum web width between the nozzle orifices 5, d) minimum nozzle needle seat angle (according to wear of the nozzle needle seat) and e) injection hole in the blade hole 2 (according to the hydrodynamic requirements) One or more values, a plurality of values, or all values of the lowest possible position of (5) are detected.

As independent parameters: a) seat angle (σ) of nozzle needle (3), b) nozzle needle peak angle (α), c) needle stroke (h), d) nozzle orifice diameter (D _L ), e) blind Hole diameter (D _e ), f) Lower needle seat diameter (D _a ), g) Blind hole angle (ε), h) Nozzle angle (κ), i) Injection point (hsp) of the injection port, k) Blind hole height (hs), l) Nozzle orifice number (n) and m) Nozzle orifice diameter (D _L ) of one or more, multiple or all values are determined.

The limits of a given parameter include a range of values or discrete values.

All technical requirements (see above) are standardized and recorded as a quality function, and the following conditions: a) the gap between the nozzle needle peak and the bottom of the blind hole 2 should not be below the minimum value; b A) the width of the nozzle needle seat should not be below the minimum, c) the width of the web between the nozzle orifices 5 should not be below the minimum, and d) the flow cross section at the blind hole inlet at the maximum nozzle needle stroke. It must be larger than the flow cross section at the edge of the lower nozzle needle seat, and e) the difference between the 1/2 seat angle (σ / 2) and the angle of the blind hole (ε) must not reach a predetermined value, and f) the angle of the blind hole ( ε) must be less than half (α / 2) of the nozzle needle peak angle, g) the gap between the top edge of the nozzle orifice in the blind hole and the edge of the blind hole inlet should not reach a defined value, h) the nozzle needle Peak angle (α) is equal to or greater than the seat angle (σ), and, i) comprises a needle seat diameter (D _a) one or more of the conditions that must be at least the blind hole diameter (D _e).

The method according to the invention involves the minimization of the quality function by a mathematical optimization algorithm simultaneously with the derivation of the optimum parameters of the injection nozzle.

Embodiments optimized according to the invention are exemplarily shown in FIG. 1 as orifice nozzles having one row of orifices with optimized parameters of the form shown below, and in FIG. 2 as orifice nozzles having two rows of orifices. .

Nozzle needle seat angle (σ) of about 84 °,

About 100 ° nozzle needle peak angle (α),

Nozzle needle stroke of about 0.5 mm (h),

Nozzle orifice diameter (D _L ) of about 0.4 mm,

Blind hole diameter (D _e ) of about 3 mm,

Lower needle sheet diameter (D _a ) of about 3.5 mm,

Blind hole angle to nozzle needle axis of 0 °

Nozzle angle of approximately 75 ° (κ),

Blind hole height (hs) of about 0.3 mm,

Injection point (hsp) of about 0.1 mm and

Nozzle Orifice Number n = 13.

Depending on the weight of the technical requirements, the improved nozzles described below can be obtained compared to the nozzles thus far. That is, the blind hole pressure rises about 10%, the blind hole volume decreases about 60%, and the web width decreases about 7%.

The spray nozzles thus developed optimize the often conflicting parameters with respect to the technical conditions for the requirements. Thus, it is ensured that the internal combustion engine with the above-described injection nozzles has a minimum of harmful substance emission, low wear and a minimum fuel consumption. At the same time, the above-described development process of the spray nozzle shown is faster and more reliable because it serves the purpose.

The aforementioned optimization method is generally suitable for all mathematically determined high level optimization tasks.

According to the present invention, it is possible to obtain a method for optimizing an injection nozzle for an internal combustion engine, which has an optimized configuration with respect to at least reduction of emission of harmful substances, improvement of wear characteristics and reduction of fuel consumption.

Claims (4)

A method of optimizing an injection nozzle for an internal combustion engine, the injection nozzle comprising a nozzle body (1) and a nozzle needle (3) movable axially against a closing pressure in a hole (2) of the nozzle body (1); This nozzle needle 3 has a valve sealing surface 4 at the combustion chamber side end face, which valve nozzle surface 1 controls the flow cross section to at least one injection port 5 which is directed into the combustion chamber of the internal combustion engine. In the optimization method of the injection nozzle for an internal combustion engine which interacts with the valve seat surface 6 of Particle Swarm Optimization (PSO) type mathematical method is used when randomly selecting independent parameters for the geometrical specification of the spray nozzle, and the criteria determined to be optimal are used when designing the spray nozzle structure. The PSO is Determining predetermined boundary conditions (nozzle type and nozzle size) for geometric specifications, Technical requirements, including the maximum pressure in the hole (blind hole) of the nozzle body, the volume of the blind hole, or the minimum nozzle needle seat angle as a target value form of the target function f (x) according to any number of independent parameters (to be optimized). Value), From the definition of the target value, deriving independent parameters (degrees of freedom) of technical requirements, including nozzle needle seat angle, lower nozzle needle seat diameter, nozzle peak angle, nozzle angle or nozzle needle stroke, Determining a parameter limit in the form of a range of values, and Mathematically weighting target values of the technical requirement in a quality function Optimization method of the injection nozzle for an internal combustion engine comprising a. The nozzle according to claim 1, wherein the injection nozzle to be optimized comprises the nozzle needle (3) and the blind hole (2) which are movably guided axially against the closing pressure in the blind hole (2) of the nozzle body (1). An orifice nozzle comprising a nozzle cone 7 closing to the combustion chamber, the nozzle needle having a conical valve sealing surface 4 at the combustion chamber side end, the valve sealing surface being at an end closed against the interior with a collar. A method of optimizing the injection nozzles for an internal combustion engine, wherein the plurality of injection holes 5 of the nozzle cone 7 extend into the combustion chamber of the internal combustion engine, interacting with the conical sealing seat surface 6 of the blade hole 2. . 3. The method of claim 2, As certain boundary conditions, those representing limitations related to nozzle type, nozzle size and other uses can be presented and can be freely predetermined. As technical requirements, a) the maximum pressure in the blind holes (thereby forming an optimum mixture), b) the minimum blind hole volume (thereby reducing carbon black and HC emissions and reducing fuel consumption), c) (depending on the required strength Minimum web width between the nozzle orifices 5, d) minimum nozzle needle seat angle (according to wear of the nozzle needle seat) and e) injection holes within the blade hole 2 (according to the hydrodynamic requirements). At least one of the lowest possible positions of 5), multiple values or all values are detected, As independent parameters: a) seat angle (σ) of nozzle needle (3), b) nozzle needle peak angle (α), c) needle stroke (h), d) nozzle orifice diameter (D _L ), e) blind hole Diameter (D _e ), f) Lower needle seat diameter (D _a ), g) Blind hole angle (ε), h) Nozzle angle (κ), i) Injection point (hsp) of the injection port, k) Blind hole height ( hs), l) the number of nozzle orifices (n) and m) one or more of the nozzle orifices diameter (D _L ), a plurality of values, or all values, Defined parameter limits include value ranges or discrete values, All the above technical requirements are standardized and recorded as a quality function, and the following conditions: a) the gap between the nozzle needle peak and the bottom of the blind hole 2 should not be below the minimum value, b) of the nozzle needle sheet The width should not be less than the minimum value, c) the width of the web between the nozzle orifices 5 should not be less than the minimum value, and d) the flow cross section at the blind hole inlet at the maximum nozzle needle stroke will be the lower nozzle needle sheet. Must be greater than the flow cross section at the edge, e) the difference between the 1/2 seat angle (σ / 2) and the blind hole angle (ε) must not reach a defined value, and f) the blind hole angle (ε) is the nozzle needle Less than half of the peak angle (α / 2), g) the gap between the top edge of the nozzle orifice in the blind hole and the edge of the blind hole inlet should not reach a specified value, h) nozzle needle peak angle (α) This city And at least one of the conditions that the needle sheet diameter (D _a ) is greater than or equal to the blind hole diameter (D _e ). delete

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