Throttle valve closed-loop control method based on air-fuel ratio requirement and intake manifold pressure acquisition method
By using a throttle closed-loop control method based on air-fuel ratio requirements, the problem of poor exhaust temperature adaptability of diesel engines in non-standard environments is solved, and the stability of intake airflow and the engine's adaptability to various environments are achieved.
Patent Information
- Application Number
- CN202511070303.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-31
- Publication Date
- 2025-11-07
AI Technical Summary
Existing diesel engines have poor exhaust temperature adaptability and unstable intake air flow under non-standard environments, which affects engine performance.
A closed-loop throttle control method based on air-fuel ratio demand is adopted. By obtaining the deviation between the engine's required intake manifold pressure and the actual intake manifold pressure, and combining PID calculation and open-loop control, the closed-loop control of the throttle is achieved to ensure intake stability.
It improves the diesel engine's exhaust temperature adaptability and intake air stability in non-standard environments, and enhances the engine's adaptability to diverse environments.
Smart Images
Figure CN120906702A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of engine control technology, in particular to a method for throttle closed-loop control based on air-fuel ratio demand and a method for obtaining intake manifold pressure. BACKGROUND
[0002] Diesel engines have high thermal efficiency and large torque output and other advantages, and are widely used in various fields. Modern diesel engines are equipped with a throttle valve in the intake system, thereby improving the thermal efficiency of the engine and increasing the output power of the engine. At present, the main control mode of the existing diesel engine throttle valve is open-loop control or closed-loop control based on boost pressure demand. When the throttle valve is in open-loop control mode, the diesel engine has the worst ability to adapt to new environments, especially in highland and high-temperature environments, which requires special modification of the throttle valve. In addition, when the throttle valve is in closed-loop control based on boost pressure demand, the engine intake will be affected by the boost pressure, the temperature after intercooling and the exhaust back pressure. When the engine is in a non-standard environment, the engine intake flow under the same boost pressure demand will be different from that on the plain, thereby affecting the adaptability of the engine exhaust temperature.
[0003] The disclosure of the above background art content is only used to assist in understanding the concept and technical solution of the present application, and it does not necessarily belong to the prior art of the present patent application. In the absence of explicit evidence that the above content has been disclosed on the filing date of the present patent application, the above background art should not be used to evaluate the novelty and inventiveness of the present application. SUMMARY
[0004] The present application is mainly aimed at providing a method for throttle closed-loop control based on air-fuel ratio demand and a method for obtaining intake manifold pressure, which is suitable for the throttle control system of existing commercial diesel engines, solves the problem of poor exhaust temperature adaptability of the engine when using boost pressure closed-loop control in a non-standard environment, has good adaptability, ensures intake stability, and improves the adaptability of the engine to multiple environments.
[0005] To this end, the present application provides a method for throttle closed-loop control based on air-fuel ratio demand and a method for obtaining intake manifold pressure.
[0006] Preferably, the present application can also have the following technical features:
[0007] A method for realizing diesel engine throttle closed-loop control based on air-fuel ratio demand, comprising the following steps:
[0008] S201, obtaining engine demand intake manifold pressure and actual intake manifold pressure;
[0009] S202, obtaining a deviation value (e(t)) of the required intake manifold pressure and the actual intake manifold pressure by subtracting the actual intake manifold pressure from the required intake manifold pressure;
[0010] S203, calculating a throttle valve closed loop control value by PID;
[0011] S204, establishing a throttle valve open loop control MAP based on the engine speed and the required injection amount; obtaining a throttle valve required opening degree pre-control value from the throttle valve open loop control MAP, and taking the throttle valve required opening degree pre-control value as a throttle valve final output pre-control value;
[0012] S205, adding the throttle valve closed loop control value and the throttle valve final output pre-control value to obtain a throttle valve final closed loop control value.
[0013] Further, in step S201, the method for obtaining the required intake manifold pressure comprises the steps of:
[0014] S101, establishing a required air-fuel ratio control MAP based on the engine speed and the required injection amount; obtaining an air-fuel ratio required value from the air-fuel ratio control MAP;
[0015] S102, obtaining the air-fuel ratio required value and the target required injection amount corresponding to the current speed and the cycle injection amount from the MAP, and multiplying the air-fuel ratio required value by the target injection amount to obtain the current required intake flow of the engine;
[0016] S103, calculating the current required intake manifold pressure based on the current required intake flow, the intake manifold temperature value, the engine speed, the engine cylinder volume, the engine charging efficiency, and two constants 0.03 and 0.348.
[0017] Further, in step S103, the current required intake manifold pressure = intake manifold temperature value X engine required intake amount ÷ engine speed ÷ engine cylinder volume ÷ engine charging efficiency ÷ 0.03 ÷ 0.348.
[0018] Further, in step S203, the throttle valve required opening degree D term calculation value, the throttle valve required opening degree I term calculation value, and the throttle valve P term calculation value are added to obtain the throttle valve closed loop control value.
[0019] Further, the throttle valve required opening degree D term calculation value is obtained based on the deviation value (e(t)) and KD (D parameter);
[0020] The formula for calculating the throttle valve required opening degree D term is:
[0021]
[0022] Further, the throttle valve required opening degree I term calculation value is obtained based on the deviation value (e(t)) and KI (I parameter);
[0023] The formula for calculating the throttle demand opening degree I term is:
[0024]
[0025] Further, based on the deviation value (e(t)) and the KP (P parameter), the throttle P term calculation value is obtained;
[0026] The formula for calculating the throttle P term is:
[0027] P = Kp * e(t).
[0028] Further, in step S204, by the current engine speed and the current demand fuel injection amount, the throttle demand opening degree pre-control value in the throttle open loop control MAP is read and used as the throttle final output pre-control value.
[0029] A method for obtaining the demand intake manifold pressure in the throttle closed loop control method described above, comprising the steps of:
[0030] S101, establishing a demand air-fuel ratio control MAP based on the engine speed and the demand fuel injection amount; obtaining the air-fuel ratio demand value from the air-fuel ratio control MAP;
[0031] S102, obtaining the air-fuel ratio demand value and the target demand fuel injection amount corresponding to the current speed and the cycle fuel injection amount from the MAP, and multiplying the air-fuel ratio demand value by the target fuel injection amount to obtain the current demand intake flow of the engine;
[0032] S103, based on the current demand intake flow, the intake manifold temperature value, the engine speed, the engine cylinder volume, the engine charging efficiency and two constants 0.03 and 0.348, the current demand intake manifold pressure is calculated.
[0033] Further, in step S103, the current demand intake manifold pressure = intake manifold temperature value X engine demand intake amount ÷ engine speed ÷ engine cylinder volume ÷ engine charging efficiency ÷ 0.03 ÷ 0.348.
[0034] The beneficial effects of the present application compared with the prior art include: solving the problem of poor adaptability of engine using boost pressure closed loop control in non-standard environment, having good adaptability, ensuring the stability of intake, and improving the adaptability of engine to multi-element environment. BRIEF DESCRIPTION OF DRAWINGS
[0035] Figure 1 is the control logic diagram of the method for realizing diesel engine throttle closed loop control based on air-fuel ratio demand of the present application.
[0036] Figure 2is a flow chart of a method for realizing diesel engine throttle closed-loop control based on air-fuel ratio demand according to the present application.
[0037] Figure 3 is a control logic diagram for obtaining demand intake manifold pressure according to the present application.
[0038] Figure 4 is a flow chart for obtaining demand intake manifold pressure according to the present application. DETAILED DESCRIPTION
[0039] The present application will be further described in conjunction with the specific embodiments and with reference to the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope of the present application and its applications.
[0040] With reference to the following drawings, non-limiting and non-exclusive embodiments will be described, in which the same reference numerals denote the same parts, unless otherwise specified.
[0041] As shown in a method for realizing diesel engine throttle closed-loop control based on air-fuel ratio demand, comprising the following steps: Figures 1-2
[0042] S201, obtaining engine demand intake manifold pressure and actual intake manifold pressure;
[0043] In step S201, the method for obtaining demand intake manifold pressure (P22) comprises the following steps:
[0044] S101, establishing demand air-fuel ratio control MAP based on engine speed and demand fuel injection amount; obtaining air-fuel ratio demand value according to air-fuel ratio control MAP, more specifically, in the air-fuel ratio control MAP, using X axis to represent engine speed, Y axis to represent demand fuel injection amount, and Z axis to represent air-fuel ratio demand value.
[0045] S102, obtaining air-fuel ratio demand value and target demand fuel injection amount corresponding to current speed and cycle fuel injection amount according to the MAP, multiplying air-fuel ratio demand value by target fuel injection amount to obtain engine current demand intake flow; specifically, calculating through ECU internal calculation logic and outputting engine current demand intake flow;
[0046] S103, calculating current intake manifold demand pressure (or called demand intake manifold pressure) based on current demand intake flow, intake manifold temperature value (T22), engine speed, engine cylinder volume, engine charge efficiency and two constants 0.03 and 0.348.
[0047] In step S103, in combination with Figures 3-4 The current engine intake manifold temperature value (T22) is monitored by an intake manifold temperature sensor and multiplied as an input value; the current actual engine speed is read and used as a divided value; the current required intake amount of the engine output in the previous stage is mainly multiplied as an input value in the calculation process; the cylinder volume of the engine is used as a divided input value; the charge efficiency corresponding to the engine at this time is used as a divided input value; in addition, the constant coefficients 0.03 and 0.348 are used as divided constants; the overall calculation process mainly uses the speed density method for calculation, and finally outputs the current required intake manifold pressure (P22) of the engine. That is, the current required intake manifold pressure = intake manifold temperature value X engine required intake amount ÷ engine speed ÷ engine cylinder volume ÷ engine charge efficiency ÷ 0.03 ÷ 0.348.
[0048] S202, obtain the deviation value (e(t)) of the required intake manifold pressure and the actual intake manifold pressure by subtracting the actual intake manifold pressure from the required intake manifold pressure;
[0049] S203, calculate the throttle closed-loop control value by PID;
[0050] In step S203, the throttle demand opening D term calculation value, the throttle demand opening I term calculation value, and the throttle P term calculation value are added to obtain the throttle closed-loop control value. Among them,
[0051] The throttle demand opening D term calculation value is obtained based on the deviation value (e(t)) and the KD (D parameter);
[0052] The formula for calculating the throttle demand opening D term is:
[0053]
[0054] The throttle demand opening I term calculation value is obtained based on the deviation value (e(t)) and the KI (I parameter);
[0055] The formula for calculating the throttle demand opening I term is:
[0056]
[0057] Among them, I k is the integral output value at the kth sampling time; K i is the integral gain coefficient; e i is the unit deviation value (e(t)) at the ith sampling time; and △t is the sampling time interval.
[0058] The throttle P term calculation value is obtained based on the deviation value (e(t)) and the KP (P parameter);
[0059] The formula for calculating the throttle P term is:
[0060] P = Kp * e(t)
[0061] S204, establishing a throttle open loop control MAP based on the engine speed and the required injection amount; obtaining a throttle required opening degree pre-control value from the throttle open loop control MAP, and taking it as the throttle final output pre-control value;
[0062] In step S204, the throttle required opening degree pre-control value in the throttle open loop control MAP is read based on the current engine speed and the current required injection amount, and taken as the throttle final output pre-control value. In the throttle open loop control MAP, the X axis represents the engine speed, the Y axis represents the engine required injection amount, and the Z axis represents the throttle required opening degree pre-control value.
[0063] S205, adding the throttle closed loop control value and the throttle final output pre-control value to obtain the throttle final closed loop control value.
[0064] In combination Figures 3-4 A method for obtaining the required intake manifold pressure in the method for obtaining the throttle closed loop control described above, comprising the steps of:
[0065] S101, establishing a required air-fuel ratio control MAP based on the engine speed and the required injection amount; obtaining the air-fuel ratio required value from the air-fuel ratio control MAP;
[0066] S102, obtaining the air-fuel ratio required value and the target required injection amount corresponding to the current speed and the cycle injection amount from the MAP, and multiplying the air-fuel ratio required value by the target injection amount to obtain the current required intake flow of the engine;
[0067] S103, calculating the current required intake manifold pressure based on the current required intake flow, the intake manifold temperature value, the engine speed, the engine cylinder volume, the engine charge efficiency, and two constants 0.03 and 0.348.
[0068] Further, in step S103, the current required intake manifold pressure = intake manifold temperature value X engine required intake amount ÷ engine speed ÷ engine cylinder volume ÷ engine charge efficiency ÷ 0.03 ÷ 0.348.
[0069] Those skilled in the art will appreciate that numerous variations are possible from the foregoing description, and therefore the embodiments and drawings are merely illustrative of one or more particular embodiments.
[0070] While there have been described and illustrated what are considered to be exemplary embodiments of the present application, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the spirit of the application. Furthermore, it is also contemplated that many modifications can be made to adapt a particular situation to the teachings of the application without departing from the central concept of the present application. Therefore, it is intended that this application not be limited to the particular embodiments disclosed, but that the application include all embodiments falling within the scope of the application.
Claims
1. A method for implementing closed loop control of a diesel engine throttle based on air-fuel ratio demand, characterized by: Comprising the following steps: S201, obtaining engine demand intake manifold pressure and actual intake manifold pressure; S202, obtaining the deviation value (e(t)) of the demand intake manifold pressure and the actual intake manifold pressure by subtracting the actual intake manifold pressure from the demand intake manifold pressure; S203, calculating the throttle closed loop control value by PID; S204, establishing a throttle open loop control MAP based on engine speed and demand fuel injection amount; obtaining the throttle demand opening degree pre-control value from the throttle open loop control MAP, and taking it as the throttle final output pre-control value; S205, adding the throttle closed loop control value and the throttle final output pre-control value to obtain the throttle final closed loop control value.
2. The method of claim 1, wherein: the air-fuel ratio demand is determined based on a torque demand and an engine speed; and the air-fuel ratio demand is determined based on a torque demand and an engine speed. In step S201, the method for obtaining the demand intake manifold pressure comprises the following steps: S101, establishing a demand air-fuel ratio control MAP based on engine speed and demand fuel injection amount; obtaining the air-fuel ratio demand value from the air-fuel ratio control MAP; S102, obtaining the air-fuel ratio demand value and the target demand fuel injection amount corresponding to the current speed and the cycle fuel injection amount from the MAP, and multiplying the air-fuel ratio demand value by the target fuel injection amount to obtain the current demand intake flow of the engine; S103, calculating the current demand intake manifold pressure based on the current demand intake flow, the intake manifold temperature value, the engine speed, the engine cylinder volume, the engine charging efficiency and two constants 0.03 and 0.
348.
3. The method of claim 2, wherein: the air-fuel ratio demand is determined based on a target engine torque and an engine speed; the engine torque is determined based on a throttle position and an engine speed; and the engine speed is determined based on a throttle position and an engine torque. In step S103, the current demand intake manifold pressure = intake manifold temperature value X engine demand intake amount ÷ engine speed ÷ engine cylinder volume ÷ engine charging efficiency ÷ 0.03 ÷ 0.
348.
4. The method of claim 1, wherein: the air-fuel ratio demand is determined based on a torque demand and an engine speed; and the air-fuel ratio demand is determined based on a torque demand and an engine speed. In step S203, the throttle closed loop control value is obtained by adding the throttle demand opening degree D term calculation value, the throttle demand opening degree I term calculation value and the throttle P term calculation value.
5. The method of claim 4, wherein: the air-fuel ratio demand is determined based on a target engine torque and an engine speed; the target engine torque is determined based on an accelerator position and a vehicle speed; and the engine speed is determined based on a vehicle speed and an engine load. The throttle demand opening degree D term calculation value is obtained based on the deviation value (e(t)) and KD (D parameter); The formula for calculating the throttle demand opening degree D term is:
6. The method of claim 4, wherein: the air-fuel ratio demand is determined based on a target engine torque and an engine speed; and the target engine torque is determined based on an accelerator pedal position, an engine coolant temperature, an engine oil temperature, an engine load, and an engine friction torque. 5 The throttle demand opening degree I term calculation value is obtained based on the deviation value (e(t)) and KI (I parameter); The formula for calculating the throttle demand opening degree I term is:
7. The method of claim 4, wherein: the air-fuel ratio demand is determined based on a target engine torque and an engine speed; and the target engine torque is determined based on an accelerator pedal position, an engine coolant temperature, an engine oil temperature, an engine load, and an engine friction torque. 5 The throttle P term calculation value is obtained based on the deviation value (e(t)) and KP (P parameter); The formula for calculating the throttle P term is: P = Kp * e(t).
8. The method of claim 1, wherein: the air-fuel ratio demand is a target air-fuel ratio; and the air-fuel ratio feedback control is performed based on a difference between the target air-fuel ratio and an actual air-fuel ratio. In step S204, the throttle demand opening degree pre-control value in the throttle open loop control MAP is read as the throttle final output pre-control value based on the current engine speed and the current demand fuel injection amount.
9. A method for acquiring a demanded intake manifold pressure in the method of throttle closed loop control according to claim 1, characterized by: Comprising the following steps: S101, establishing a demand air-fuel ratio control MAP based on engine speed and demand fuel injection amount; obtaining the air-fuel ratio demand value from the air-fuel ratio control MAP; S102, obtaining the air-fuel ratio demand value and the target demand fuel injection amount corresponding to the current speed and the cycle fuel injection amount from the MAP, and multiplying the air-fuel ratio demand value by the target fuel injection amount to obtain the current demand intake flow of the engine; S103, calculating the current demand intake manifold pressure based on the current demand intake flow, the intake manifold temperature value, the engine speed, the engine cylinder volume, the engine charging efficiency and two constants 0.03 and 0.
348.
10. The method of acquiring demand intake manifold pressure of claim 9, wherein: In step S103, the current required intake manifold pressure = intake manifold temperature value X engine required intake volume ÷ engine rotation speed ÷ engine cylinder volume ÷ engine charging efficiency ÷ 0.03 ÷ 0.348.