A speed control method for an electronically controlled fuel injection engine

Abstract

The present invention discloses a speed control method for an electronically controlled injection engine. The method specifically includes the following steps: obtaining the difference between the target engine speed and the actual engine speed; using the cumulative PI control method to control the difference between the target engine speed and the actual engine speed to obtain the fuel injection control system cyclic fuel supply coefficient of the engine, so as to achieve speed control. On the basis of the classical PI control, the method improves the proportional operation link, introduces a feedback mechanism, and the feedback link has an adjustable coefficient, so that the output of the feedback link can be adjusted and optimized. The coefficient of the feedback link can be adjusted under static or dynamic conditions. The implementation of the solution of the present invention enhances the actual effectiveness of the proportional operation link. The solution of the present invention is suitable for application in the fields of engine speed control, fuel electronic injection control, or other control fields based on PI regulation.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and particularly to a speed control method for an electronically controlled engine. Background Art

[0002] With the progress of engine technology and electronic control technology, and the continuous improvement of the comprehensive performance requirements such as engine performance and emissions, the application of engine fuel electronic injection control technology in the engine field has become more and more popular. Especially for high-power diesel engines used in fields such as railways, ships, and stationary power stations, they are gradually realizing electronic injection.

[0003] Through the engine fuel electronic injection controller (hereinafter referred to as the electronic injection controller), according to the actual engine speed and the target speed, PI operations are performed, and the related algorithms and technologies for real-time control of the fuel injection amount have been relatively popular and mature. The classic PI control algorithm is derived from the classic PI control algorithm of the position control system. Its control logic is to dynamically compare the actual position and the target position, perform P (proportional) operations and I (integral) operations, and comprehensively control the parameters of the actuator based on the results of the P and I operations, thereby affecting the actual position. The characteristic of such position PI control is that through the control of the actuator, the actual position can be continuously changed. Usually, only by using P (proportional operation) can the actual position gradually approach the target position and oscillate near the target position. The I (integral operation) is used to improve the stability of the control system.

[0004] Currently, most electronic injection controllers still use the classic PI control algorithm. However, such algorithms have certain limitations for engine speed control and fuel quantity control. The result of the PI operation is usually the engine load or the fuel injection amount, and the actual engine speed is affected through this result. However, different from the fixed output result of the position PI control method that can continuously affect the actual position, the fixed engine load or fuel injection amount cannot continuously affect the actual engine speed, resulting in the failure of the P (proportional) operation, directly affecting the response speed and stability of the control system. Specifically, the P (proportional) operation calculates the difference between the engine target speed and the actual speed, multiplies it by the Kp (proportional) coefficient to obtain the P (proportional) operation result, which is the engine load or the fuel injection amount. However, the fixed engine load or fuel injection amount cannot continuously change the actual engine speed. Nor does it meet the result that in PI control, when a step occurs, using a fixed Kp (proportional) coefficient can also make the actual value fluctuate around the target value. As a result, the adjustment of the engine speed is actually regulated by the I (integral) operation, and the effectiveness of the P (proportional) operation cannot be exerted, thereby causing a contradiction between the response speed and stability of the engine speed control.

[0005] It can be seen that the classic positional PI control algorithm cannot fully meet the needs of engine speed control. To improve the engine speed control performance, it is necessary to develop a new PI control algorithm suitable for the characteristics of such applications. Summary of the Invention

[0006] According to the problems existing in the prior art, the present invention discloses a speed control method for an electronically controlled engine, which specifically includes the following steps:

[0007] Obtain the difference between the engine target speed and the actual speed;

[0008] Use the cumulative PI control method to control the difference between the engine target speed and the actual speed to obtain the cyclic fuel supply coefficient of the engine fuel injection control system, thereby realizing speed control.

[0009] The difference between the engine target speed and the actual speed is controlled by the cumulative PI control method to obtain the cyclic fuel supply coefficient of the engine fuel injection control system:

[0010] Multiply the difference err(n) between the engine target speed and the actual speed by the proportional coefficient Kp to obtain the current difference multiple OP_P(n);

[0011] Add the current difference multiple OP_P(n) to the third difference multiple OP_P3(n - 1) to obtain the first difference multiple OP_P1(n);

[0012] Where the current third difference multiple OP_P3(n - 1) = OP_P2(n - 1) * Kp1; where: 0 < Kp1 < 1;

[0013] OP_P2(n - 1) = 1 / Z (the current difference multiple OP_P(n) + the previous third difference multiple OP_P3(n - 1));

[0014] The first difference multiple OP_P1(n) undergoes I operation to obtain the integral difference multiple;

[0015] Add the first difference multiple OP_P1(n) to the integral difference multiple to obtain the cyclic fuel supply adjustment coefficient of the engine fuel injection control system.

[0016] An electronically controlled engine speed control device, comprising:

[0017] An acquisition module: used to obtain the difference between the engine target speed and the actual speed;

[0018] A control module: used to control the difference between the engine target speed and the actual speed by the cumulative PI control method to obtain the cyclic fuel supply coefficient of the engine fuel injection control system; thereby realizing speed control.

[0019] Due to the above technical solution, an electronic fuel injection engine speed control method provided by the present invention improves the proportional operation link on the basis of classical PI control, introduces a feedback mechanism, and the feedback link has an adjustable coefficient, so that the output of the feedback link can be adjusted and optimized. The coefficient of the feedback link can be adjusted both statically and dynamically. The implementation of the solution of the present invention enhances the actual effectiveness of the proportional operation link. The solution of the present invention is suitable for application in the fields of engine speed control, fuel electronic injection control, or other control fields based on PI regulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 is the schematic diagram of the electronic fuel injection engine speed control method of the present invention

[0022] Figure 2 is the flow chart of the electronic fuel injection engine speed control method of the present invention DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] To make the technical solutions and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention:

[0024] As Figure 1 shown, an electronic fuel injection engine speed control method is a new type of PI control principle developed on the basis of the classical PI control principle and in combination with the characteristics of the engine fuel injection control system, which solves the problem that in a non-position type PI control system, the use of the classical control principle causes the P (proportional) operation to fail or cannot achieve the expected effect.

[0025] The method disclosed in the present invention is mainly realized by the engine fuel injection control system for regulating the cyclic fuel supply. The difference between the target speed and the actual speed, that is, the speed difference (target speed - actual speed), is subjected to PI operation to obtain the cyclic fuel supply.

[0026] In the PI operation of this solution, the original I operation remains unchanged, and the P operation is carried out according to Figure 1Perform operations and control. The current rotational speed difference err(n), as the system input, is multiplied by the proportionality coefficient (Kp) to obtain the current OP_P(n); OP_P(n) is added to OP_P3(n - 1) to obtain OP_P1(n). OP_P1(n), as the output result of the P operation, is combined with the output result of the I operation for subsequent PI control. Record the current OP_P1(n) for the next P operation as OP_P2(n - 1), and OP_P2(n - 1) is multiplied by Kp1 (where Kp1 is greater than 0 and less than 1) to obtain OP_P3(n - 1) for the next P operation.

[0027] Where err(n) is the current rotational speed difference, OP_P(n) is the output of the current basic P operation, OP_P1(n) is the output of the current comprehensive P operation, OP_P2(n - 1) is the output of the previous comprehensive P operation, Kp1 is the feedback proportionality coefficient (used to calculate the cumulative proportion of the previous calculation result), and OP_P3(n - 1) is the feedback cumulative amount of the previous P operation.

[0028] For the PI control logic of the engine fuel injection control system software, as Figure 2 shown, the following specific method is adopted:

[0029] 1) Regularly enter the PI operation process 1.1 and enter process 1.2;

[0030] 2) Enter process 1.2, obtain the output OP_P2(n - 1) of the previous comprehensive P operation, and enter process 1.3;

[0031] 3) Enter process 1.3, obtain the feedback proportionality coefficient Kp1, and enter process 1.4;

[0032] 4) Enter process 1.4, calculate the feedback cumulative amount OP_P3(n - 1) of the previous P operation as OP_P3(n - 1)=OP_P2(n - 1)*Kp1, and enter process 1.5;

[0033] 5) Enter process 1.5, calculate the current rotational speed difference err(n)=target rotational speed - actual rotational speed, and enter process 1.6;

[0034] 6) Enter process 1.6, calculate the output OP_P(n) of the current basic P operation as OP_P(n)=err(n)*Kp, and enter process 1.7;

[0035] 7) Enter process 1.7, calculate the output OP_P1(n) of the current comprehensive P operation as OP_P1(n)=OP_P(n)+OP_P3(n - 1), and enter process 1.8;

[0036] 8) Enter process 1.8, calculate the result of this PI operation OP_PI(n) = OP_P1(n) + OP_I(n), and enter process 1.9; Note: OP_I(n) is the output result of this I operation, and OP_PI(n) is the result of this PI operation;

[0037] 9) Enter process 1.9, output the result of this PI operation OP_PI(n), and enter process 1.10;

[0038] Enter process 1.10 to complete this PI operation.

[0039] The present invention discloses an electronic fuel injection engine speed control device, including:

[0040] An acquisition module: used to acquire the difference between the target engine speed and the actual engine speed;

[0041] A control module: used to control the difference between the target engine speed and the actual engine speed by using the cumulative PI control method to obtain the fuel injection control system cyclic fuel supply coefficient of the engine; thereby realizing speed control.

[0042] An electronic fuel injection engine speed control method disclosed by the present invention can form internal feedback accumulation for the P operation, conform to the actual situation of engine speed control / fuel injection control, realize a stable and reliable P operation effect, and the proportion of internal feedback accumulation formed by the P operation can be statically or dynamically adjusted according to actual needs to further optimize the P operation efficiency. Because this technical solution realizes the actual output efficiency of the P operation, it further reduces the burden of the I operation, improves the stability of the system, and reduces the debugging difficulty of the PI parameters.

[0043] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered by the protection scope of the present invention.

Claims

1. A speed control method for an electronically fuel-injected engine, characterized in that: It includes the following steps: Obtain the difference between the target engine speed and the actual engine speed; Use the difference between the target engine speed and the actual engine speed to control the fuel injection control system's cyclic fuel supply coefficient of the engine by means of the cumulative PI control method, thereby achieving speed control; The cumulative PI control method is: enter the PI operation process regularly; Obtain the previous comprehensive P operation output OP_P2(n - 1); Obtain the feedback proportional coefficient Kp1; Calculate the previous P operation feedback cumulative amount OP_P3(n - 1)=OP_P2(n - 1)*Kp1; Calculate the current speed difference err(n)=target speed - actual speed; Calculate the current basic P operation output OP_P(n)=err(n)*Kp; Calculate the current comprehensive P operation output OP_P1(n)=OP_P(n)+OP_P3(n - 1); Calculate the current PI operation result OP_PI(n)=OP_P1(n)+OP_I(n), where OP_I(n) is the current I operation output result and OP_PI(n) is the current PI operation result; Output the current PI operation result OP_PI(n) to complete the current PI operation.

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