阅读说明：本技术 控制发动机高压油管油压的方法 (Method for controlling oil pressure of high-pressure oil pipe of engine ) 是由 亓晋 巩锟 闫文卿 孙雁飞 于 2019-11-21 设计创作，主要内容包括：本发明提供了一种控制发动机高压油管油压的方法,主要包括以下步骤：计算初始时刻高压油管内燃油的参数；通过遍历算法计算发动机的进油量和出油量,以控制发动机高压油管内的油压；计算高压油管内燃油压力达到预期值时的进油量最优解和出油量最优解。相较于现有技术,本发明采用遍历算法灵活调节发动机高压油管内的油压,使发动机高压油管的油压升高、降低或保持不变,对发动机高压油管燃油的进油量和出油量实现了自动化控制。(The invention provides a method for controlling oil pressure of a high-pressure oil pipe of an engine, which mainly comprises the following steps: calculating the parameters of fuel oil in the high-pressure oil pipe at the initial moment; calculating the oil inlet amount and the oil outlet amount of the engine through a traversal algorithm to control the oil pressure in a high-pressure oil pipe of the engine; and calculating the optimal solution of the oil inlet quantity and the optimal solution of the oil outlet quantity when the oil pressure in the high-pressure oil pipe reaches the expected value. Compared with the prior art, the invention adopts the traversal algorithm to flexibly adjust the oil pressure in the high-pressure oil pipe of the engine, so that the oil pressure of the high-pressure oil pipe of the engine is increased, reduced or kept unchanged, and the automatic control on the oil inlet quantity and the oil outlet quantity of the fuel oil of the high-pressure oil pipe of the engine is realized.)

1. A method for controlling oil pressure of a high-pressure oil pipe of an engine is characterized by mainly comprising the following steps:

step 1, calculating parameters of fuel in a high-pressure oil pipe at an initial moment;

step 2, calculating the oil inlet amount and the oil outlet amount of the engine through a traversal algorithm to control the oil pressure in a high-pressure oil pipe of the engine;

and 3, calculating an oil inlet quantity optimal solution and an oil outlet quantity optimal solution when the oil pressure in the high-pressure oil pipe reaches a desired value.

2. The method of controlling engine high pressure line oil pressure as set forth in claim 1, wherein: in step 1, the parameters include fuel pressure density, one-way valve period, cam angular velocity, and needle lift.

3. The method for controlling the oil pressure of the high-pressure oil pipe of the engine as claimed in claim 2, wherein the step 2 specifically comprises:

step 21, determining a variable of the first traversal, performing the first traversal, and performing the traversal within a possible interval range according to the change of the parameters of the fuel in the high-pressure oil pipe along with the time so as to obtain the change range of the fuel pressure in the high-pressure oil pipe when the fuel inlet amount of the oil inlet changes within a certain time;

step 22, calculating the oil inlet amount of the engine at the moment;

step 23, determining a variable of the second traversal, performing the second traversal, and performing the traversal within a possible interval range according to the change of the parameters of the fuel in the high-pressure oil pipe along with the time so as to obtain the change range of the fuel pressure in the high-pressure oil pipe when the fuel output of the fuel injection nozzle changes within a certain time;

and 24, calculating the parameters of the fuel in the high-pressure oil pipe at the moment.

4. The method of controlling engine high pressure line oil pressure according to claim 3, characterized by: the variable traversed for the first time in step 21 is the cam angular velocity, and the value of the cam angular velocity is traversed within the range of possible intervals.

5. The method of controlling engine high pressure line oil pressure according to claim 3, characterized by: in the step 23, the oil outlet quantity of the oil nozzle can be obtained by calculation according to the relationship between the lift of the needle valve and the time.

6. The method of claim 3, wherein step 2 further comprises a third traversal of time, the steps comprising:

step 25, taking time as a variable, and traversing the time for the third time to observe the change of the fuel pressure in the high-pressure oil pipe at each moment;

and 26, after the third traversal is finished, obtaining the variation range of the fuel pressure in the high-pressure fuel pipe within a certain time under the conditions determined by the first traversal and the second traversal.

7. The method of controlling engine high pressure line oil pressure according to claim 6, characterized by: different step sizes of traversal may be set for the time variable in step 25.

8. The method of controlling engine high pressure line oil pressure as set forth in claim 1, wherein: the oil pressure in the high-pressure oil pipe of the engine is determined by the opening state of a check valve above the high-pressure oil pipe and an oil nozzle below the high-pressure oil pipe.

9. The method for controlling the oil pressure of the high-pressure oil pipe of the engine according to claim 8, wherein the judgment formula of the open state of the check valve is as follows:

wherein u represents the open state of the check valve, P_leftIndicating the fuel pressure in the plunger chamber, P_centerThe pressure of fuel in the high-pressure oil pipe is shown, and when the pressure of the fuel in the plunger cavity is greater than that of the fuel in the high-pressure oil pipe, the check valve is opened; when the fuel pressure in the plunger cavity is smaller than the internal combustion oil pressure of the high-pressure oil pipeWhen force is applied, the check valve closes.

10. The method of controlling engine high pressure line oil pressure according to claim 2, characterized by: the cam angular speed can be used for controlling the oil inlet amount of the high-pressure oil pipe.

Technical Field

The invention relates to a method for controlling oil pressure of a high-pressure oil pipe of an engine, belonging to the field of engine oil pressure control.

Background

The high-pressure oil pipe is the basis of the work of many fuel engines, and in the work of the fuel engines, the treated high-pressure fuel enters the high-pressure oil pipe from the high-pressure oil pump and is sprayed out from the oil spray nozzle, and the pressure in the high-pressure oil pipe can be changed continuously in the process, so that the quantity of the fuel sprayed out from the oil spray nozzle can be changed, and the work stability of the engines is further influenced. In order to make the fuel engine work stably, it is very important to control the pressure stability of the fuel in the high-pressure oil pipe, and the traditional fuel engine cannot realize the automatic control of the oil pressure change in the high-pressure oil pipe.

The least square method can be used for finding the optimal function matching of data through the sum of squares of the minimized errors, and the oil pressure in the oil pipe can be subjected to target planning based on the least square method. The traversal algorithm can find out the global optimal solution, and when the search range is large and the search step length is small, the search speed is slow. The particle swarm algorithm has the advantages that a local optimal solution can be found, but the searching speed is high. Therefore, when the oil pressure change in the oil pipes of different types of engines is controlled, different algorithms can be respectively used for solving the control method.

In view of the above, it is necessary to provide a method for controlling the oil pressure of the high-pressure oil pipe of the engine to solve the above problems.

Disclosure of Invention

The invention aims to provide a method for controlling the oil pressure of a high-pressure oil pipe of an engine so as to realize automatic control of oil pressure change in the high-pressure oil pipe.

In order to achieve the purpose, the invention provides a method for controlling the oil pressure of a high-pressure oil pipe of an engine, which mainly comprises the following steps:

step 1, calculating parameters of fuel in a high-pressure oil pipe at an initial moment;

step 2, calculating the oil inlet amount and the oil outlet amount of the engine through a traversal algorithm to control the oil pressure in a high-pressure oil pipe of the engine;

and 3, calculating an oil inlet quantity optimal solution and an oil outlet quantity optimal solution when the oil pressure in the high-pressure oil pipe reaches a desired value.

Optionally, in step 1, the parameters include fuel pressure density, one-way valve period, cam angular velocity, and needle lift.

Optionally, step 2 specifically includes:

step 21, determining a variable of the first traversal, performing the first traversal, and performing the traversal within a possible interval range according to the change of the parameters of the fuel in the high-pressure oil pipe along with the time so as to obtain the change range of the fuel pressure in the high-pressure oil pipe when the fuel inlet amount of the oil inlet changes within a certain time;

step 22, calculating the oil inlet amount of the engine at the moment;

step 23, determining a variable of the second traversal, performing the second traversal, and performing the traversal within a possible interval range according to the change of the parameters of the fuel in the high-pressure oil pipe along with the time so as to obtain the change range of the fuel pressure in the high-pressure oil pipe when the fuel output of the fuel injection nozzle changes within a certain time;

and 24, calculating the parameters of the fuel in the high-pressure oil pipe at the moment.

Optionally, the variable traversed for the first time in step 21 is the cam angular velocity, and the value of the cam angular velocity is traversed within the possible interval range.

Optionally, in step 23, the oil outlet amount of the oil nozzle may be calculated according to a relationship between the lift of the needle valve and time.

Optionally, step 2 further includes traversing time for a third time, and the specific steps include:

step 25, taking time as a variable, and traversing the time for the third time to observe the change of the fuel pressure in the high-pressure oil pipe at each moment;

and 26, after the third traversal is finished, obtaining the variation range of the fuel pressure in the high-pressure fuel pipe within a certain time under the conditions determined by the first traversal and the second traversal.

Optionally, different traversal steps can be set for the time variable in step 25.

Optionally, the oil pressure in the high-pressure oil pipe of the engine is determined by the opening state of a check valve above the high-pressure oil pipe and an oil nozzle below the high-pressure oil pipe.

Optionally, the formula for determining the open state of the check valve is as follows:

wherein u represents the open state of the check valve, P_leftIndicating the fuel pressure in the plunger chamber, P_centerThe pressure of fuel in the high-pressure oil pipe is shown, and when the pressure of the fuel in the plunger cavity is greater than that of the fuel in the high-pressure oil pipe, the one-way valveOpening; when the fuel pressure in the plunger cavity is smaller than the fuel pressure in the high-pressure fuel pipe, the one-way valve is closed.

Optionally, the cam angular velocity can be used for controlling the oil inlet amount of the high-pressure oil pipe.

The invention has the beneficial effects that: the invention adopts the traversal algorithm to flexibly adjust the oil pressure in the high-pressure oil pipe of the engine, so that the oil pressure of the high-pressure oil pipe of the engine is increased, reduced or kept unchanged, and the automatic control on the oil inlet quantity and the oil outlet quantity of the fuel oil in the high-pressure oil pipe of the engine is realized.

Drawings

FIG. 1 is an exploded view of the method of controlling engine high pressure line oil pressure according to the present invention.

Fig. 2 is a schematic structural view of a simple high pressure tubing system.

FIG. 3 is a flow chart of the traversal algorithm in the preferred embodiment of the present invention.

Fig. 4 is a flow chart of a particle swarm algorithm based on the least square concept in another embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings and specific embodiments.

The invention discloses a method for controlling oil pressure of a high-pressure oil pipe of an engine, which can selectively use a traversal algorithm and a particle swarm algorithm based on a least square idea to control the oil inlet quantity of a check valve and the oil outlet quantity of an oil nozzle of the high-pressure oil pipe of the engine according to the oil pressure change conditions in the oil pipes of different types of engines so as to realize automatic control of the oil pressure of the high-pressure oil pipe of the engine.

As shown in fig. 1, with an arbitrary time as an initial time, knowing the oil pressure of the high-pressure oil pipe at the initial time, relevant property parameters such as the pressure density of the fuel oil in the high-pressure oil pipe, the period of the one-way valve, the cam angular velocity, the needle valve lift and the like can be calculated through relevant existing formulas, at this time, the pressure of the fuel oil in the high-pressure oil pipe can affect the oil inlet amount of the fuel oil at the oil inlet, and the oil inlet amount can also affect the pressure of the fuel oil in the high-pressure oil pipe, namely, the parameter of the fuel oil in the last second determines the. The fuel pressure in the high-pressure oil pipe rises, the fuel spray nozzle is opened to spray oil outwards, and the fuel pressure in the high-pressure oil pipe can also be changed according to the oil output quantity.

The traversal algorithm is used for controlling the change of the oil pressure in the high-pressure oil pipe by controlling the opening period (or the opening state) of a check valve above the high-pressure oil pipe and an oil nozzle below the high-pressure oil pipe under the condition that the oil inlet amount is fixed or the fuel system is simply arranged, and specifically comprises the following steps:

step 1, calculating parameters of fuel in a high-pressure oil pipe at an initial moment;

step 2, calculating the oil inlet amount and the oil outlet amount of the engine through a traversal algorithm to control the oil pressure in a high-pressure oil pipe of the engine;

and 3, calculating an oil inlet quantity optimal solution and an oil outlet quantity optimal solution when the oil pressure in the high-pressure oil pipe reaches a desired value.

Wherein, step 2 specifically includes:

step 21, determining a variable of the first traversal, performing the first traversal, and performing the traversal within a possible interval range according to the change of the parameters of the fuel in the high-pressure oil pipe along with the time so as to obtain the change range of the fuel pressure in the high-pressure oil pipe when the fuel inlet amount of the oil inlet changes within a certain time;

step 22, calculating the oil inlet amount of the engine at the moment;

step 23, determining a variable of the second traversal, performing the second traversal, and performing the traversal within a possible interval range according to the change of the parameters of the fuel in the high-pressure oil pipe along with the time so as to obtain the change range of the fuel pressure in the high-pressure oil pipe when the fuel output of the fuel injection nozzle changes within a certain time;

and 24, calculating the parameters of the fuel in the high-pressure oil pipe at the moment.

Further, step 2 further includes traversing time for a third time, and the specific steps include:

step 25, taking time as a variable, and traversing the time for the third time to observe the change of the fuel pressure in the high-pressure oil pipe at each moment; it should be noted that, in this step, different traversal step lengths may be set for the time variables;

and 26, after the third traversal is finished, obtaining the variation range of the fuel pressure in the high-pressure fuel pipe within a certain time under the conditions determined by the first traversal and the second traversal.

In order to further describe the present application in detail, the present invention will be subjected to a simulation experiment as follows.

As shown in fig. 2, a simple structure diagram of the high pressure oil pipe system, by analyzing the working principle of the high pressure oil pipe system, the relation of the plunger lift with respect to the cam angular velocity and the time can be obtained:

h(t)＝-2.413cosωt+2.413，

and the variation relation of the needle valve lift along with time:

h₁(t)＝-799.1t⁵+597.2t⁴-106t³+10.21t²-0.3637t+0.002418，

the working cycle of the check valve is set to be 10ms after 0.308ms of working, and the initial pressure of the fuel in the high-pressure fuel pipe is 100 MPa.

As shown in fig. 3 in combination with fig. 2, the oil pressure in the high-pressure oil pipe can be controlled to be 100MPa by using a traversal algorithm, which specifically includes the following steps:

step 1, calculating parameters of fuel in a high-pressure oil pipe at an initial moment;

step 21, determining the cam angular velocity as a variable of the first traversal, taking 100r/ms as a step length, traversing the value of the cam angular velocity between 400 and 4600r/ms, assuming that the plunger in the high-pressure oil pump starts to move from the bottom dead center at the initial time, and determining the opening state of the check valve at each subsequent time:

wherein u represents the open state of the check valve, P_leftIndicating the fuel pressure in the plunger chamber, P_centerThe pressure of fuel in the high-pressure oil pipe is shown, and when the pressure of the fuel in the plunger cavity is greater than that of the fuel in the high-pressure oil pipe, the check valve is opened; when the pressure of the fuel in the plunger cavity is less than that in the high-pressure fuel pipeWhen the fuel pressure is high, the check valve is closed;

step 22, calculating the oil inlet amount of the engine at the moment according to a calculation formula of the inlet and outlet flow of the fuel oil and a density formula of the fuel oil through the known parameters of the fuel oil in the high-pressure oil pipe;

step 23, determining a variable of the second traversal (according to specific requirements) and performing the second traversal, obtaining the oil output at the moment according to the relation between the needle valve lift and time, and performing traversal in a possible interval range according to the change of the parameters of the fuel oil in the high-pressure oil pipe along with time so as to obtain the change range of the fuel oil pressure in the high-pressure oil pipe when the oil output of the fuel injection nozzle changes within a certain time;

step 24, calculating the pressure density of the fuel in the high-pressure fuel pipe at the moment;

step 25, traversing the time for the third time, taking 0.01ms as a step length, and calculating the fluctuation value of the fuel pressure of the high-pressure fuel pipe within 0-15000ms under the condition that the cam angular velocity is determined;

26, after the third traversal is finished, obtaining the variation range of the fuel pressure in the high-pressure fuel pipe within a certain time under the conditions determined by the first traversal and the second traversal;

and 3, calculating an oil inlet quantity optimal solution and an oil outlet quantity optimal solution when the oil pressure in the high-pressure oil pipe reaches a desired value.

The calculation result shows that the cam angular velocity for stabilizing the pressure of the fuel in the high-pressure oil pipe at 100MPa is 2700r/min, and the change of the cam angular velocity can increase the pressure change amplitude of the fuel in the high-pressure oil pipe, so that the following results can be seen: the invention can effectively control the pressure of the fuel in the high-pressure oil pipe through the traversal algorithm.

In another embodiment of the invention, if the oil inlet amount is influenced by other machines in the high-pressure oil pump or the number of the oil nozzles is large, namely the structure of the fuel system is complicated, the oil pressure of the high-pressure oil pipe of the engine can be automatically controlled by adopting a particle swarm algorithm based on the least square thought.

The oil injection valve is additionally arranged on the basis of a simple high-pressure oil pipe system, the pressure reducing valve with the outlet diameter of 1.4mm is additionally arranged at the left end of the high-pressure oil pipe, the working period and the working time of the pressure reducing valve and the one-way valve are the same, the oil inlet amount is controlled through the angular speed of a cam in the high-pressure oil pump, and the oil outlet amount of the high-pressure oil pipe is controlled through the working time interval of the two oil injection valves. After an oil injection nozzle is added, the high-pressure oil pipe system has four variables, namely the working period and the working time of a one-way valve, the cam angular velocity and the working time difference of the two oil injection nozzles, and the time spent by using a traversal algorithm is more, so that the fuel pressure of the high-pressure oil pipe is controlled by adopting a particle swarm algorithm based on the least square idea.

As shown in fig. 4, the method specifically includes the following steps:

step a, initializing a particle swarm, determining the size of the swarm to be N (50), having N (4) parameters, and randomly setting the initial position (x) of a particle i_i1,x_i2,x_i3,x_i4) And a velocity v;

and b, calculating the fitness of each particle, and determining a fitness function as follows based on the least square thought:

f(x)＝min(x_i-100)²，

the fitness function is the limit of minimum pressure change in the high-pressure oil pipe based on the least square thought, wherein x_iRepresenting the pressure value of the particle i, wherein x is the expected value of the oil pressure in the high-pressure oil pipe;

step c, updating the position and the speed of the particles according to a fitness function, calculating the fitness of the particles, comparing the fitness with the individual extreme value (the optimal solution found by each particle) of the particles to find a global value from the optimal solutions, namely the global optimal solution, and comparing and updating the global optimal solution with the historical optimal position; assuming that the historical optimal position of the particle is p and the historical optimal position of the particle swarm is g, the updated function is:

v＝w*v+c₁r₁(p-x)+c₂r₂(p-x)，

wherein r is₁And r₂Is [0,1 ]]Random number of c₁And c₂W v denotes the tendency of the particle to maintain its own velocity as an acceleration constant, c₁r₁(p-x) represents the tendency of the particle to move towards the optimal position of the particle, c₂r₂(p-x) represents a trend of particles toward the optimal location of the population;

and d, finishing if the maximum iteration times are reached, otherwise, turning to the step b.

The particle swarm algorithm based on the least square idea can obtain the values of four parameters which enable the change range of the fuel pressure of the high-pressure fuel pipe to be minimum, the working period of the check valve is 283ms, the working time is 0.706ms, the working time difference of two fuel nozzles is 90ms, the angular speed of a gear in a fuel injection pump is 0.594rad/ms, the average absolute error of the fuel pressure fluctuation in the high-pressure fuel pipe is 1.1290MPa, and the error is about 1 percent, so that the conclusion can be obtained: the method has good control effect on the fuel pressure in the high-pressure fuel pipe.

In conclusion, the invention adopts the traversal algorithm to flexibly adjust the oil pressure in the high-pressure oil pipe of the engine, so that the oil pressure of the high-pressure oil pipe of the engine is increased, reduced or kept unchanged, and the automatic control on the oil inlet quantity and the oil outlet quantity of the fuel oil of the high-pressure oil pipe of the engine is realized; and under the condition that a fuel system is complex, the oil pressure of a high-pressure oil pipe of the engine can be automatically controlled by adopting a particle swarm algorithm based on the least square idea. Compared with the prior art, the method can selectively use the traversal algorithm and the particle swarm algorithm based on the least square thought to control the oil inlet quantity of the check valve of the high-pressure oil pipe of the engine and the oil outlet quantity of the oil nozzle according to the oil pressure change conditions in the oil pipes of different types of engines, so as to realize automatic control of the oil pressure of the high-pressure oil pipe of the engine.

Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the present invention.