阅读说明：本技术 发动机的egr阀控制方法 (EGR valve control method for engine ) 是由 何笃算 于 2021-03-05 设计创作，主要内容包括：本发明公开了发动机的EGR阀控制方法,其控制方法包括以下步骤：A、通过EGR阀控制器计算再循环的废气的所需量；B、通过EGR阀控制器获取发动机的第二管路的第一压力值,将第一压力值与第一预设值进行比较,当第一压力值不小于第一预设值时,获取空气滤清器下游的第二压力值,将第二压力值记为EGR阀下游的预估压力值,当第一压力值小于第一预设值时,确定压力比值和节流阀上游的压力值。本发明实现了能够调节EGR阀开度的目的,能够根据发动机的工作状态调节EGR阀的开度,从而对废气的循环量进行实时控制,满足当今市场的需求,提高了发动机EGR阀的实用性和使用性,解决了以往发动机EGR阀控制效果不佳的问题。(The invention discloses an EGR valve control method of an engine, which comprises the following steps: A. calculating a required amount of recirculated exhaust gas by an EGR valve controller; B. the method comprises the steps of obtaining a first pressure value of a second pipeline of the engine through an EGR valve controller, comparing the first pressure value with a first preset value, obtaining a second pressure value of the downstream of an air filter when the first pressure value is not smaller than the first preset value, recording the second pressure value as an estimated pressure value of the downstream of the EGR valve, and determining a pressure ratio and a pressure value of the upstream of a throttle valve when the first pressure value is smaller than the first preset value. The EGR valve disclosed by the invention can be used for realizing the purpose of adjusting the opening degree of the EGR valve, and adjusting the opening degree of the EGR valve according to the working state of an engine, so that the circulation quantity of waste gas is controlled in real time, the requirements of the current market are met, the practicability and usability of the EGR valve of the engine are improved, and the problem of poor control effect of the EGR valve of the engine in the past is solved.)

1. An EGR valve control method of an engine, characterized in that: the control method comprises the following steps:

A. calculating a required amount of recirculated exhaust gas by an EGR valve controller;

B. the method comprises the steps that a first pressure value of a second pipeline of the engine is obtained through an EGR valve controller, the first pressure value is compared with a first preset value, when the first pressure value is not smaller than the first preset value, a second pressure value of the downstream of an air filter is obtained, the second pressure value is recorded as an estimated pressure value of the downstream of the EGR valve, when the first pressure value is smaller than the first preset value, a pressure ratio and a pressure value of the upstream of a throttle valve are determined, the pressure value of the downstream of the throttle valve is determined according to the pressure ratio and the pressure value of the upstream of the throttle valve, the pressure value of the downstream of the throttle valve is recorded as the estimated pressure value of the downstream;

C. when the first pressure value is not smaller than the first preset value, acquiring a second pressure value at the downstream of the air filter, recording the second pressure value as an estimated pressure value at the downstream of the EGR valve, when the first pressure value is not smaller than the first preset value, determining that the engine is in a first operation working condition, when the engine is in the first operation working condition, controlling the opening of the throttle valve to be the maximum opening, acquiring the second pressure value at the downstream of the air filter, and recording the second pressure value as the estimated pressure value at the downstream of the EGR valve;

D. when the first pressure value is smaller than a first preset value, determining a pressure ratio and a pressure value at the upstream of the throttle valve, and acquiring the opening of the throttle valve, the pressure value at the upstream of the throttle valve and the air flow passing through the throttle valve;

E. determining a pressure ratio according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, determining a pressure ratio function relation according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, and calculating a dependent variable of a pressure ratio function;

F. controlling the opening degree of the EGR valve according to the estimated pressure value at the downstream of the EGR valve, and acquiring the opening degree value of the EGR valve according to the estimated pressure value at the downstream of the EGR valve and a second data table;

G. adjusting the opening degree of the EGR valve so that the opening degree of the EGR valve becomes the second EGR valve opening degree by increasing the opening degree of the EGR valve by a predetermined increase amount from the first EGR valve opening degree when the temperature of the exhaust gas discharged from the combustion chamber exceeds a predetermined reference temperature;

H. determining whether the EGR rate exceeds a reference EGR rate, and adjusting and reducing the EGR valve opening degree so that the EGR rate becomes equal to or less than the set reference EGR rate in a state of being adjusted to the second EGR valve opening degree;

I. the temperature when the engine is started is obtained through the EGR valve controller, the EGR valve is allowed to be opened when the engine starting temperature accords with a first preset temperature interval, otherwise, the EGR valve is not allowed to be opened, the working temperature of the EGR valve body is calculated, the EGR valve is allowed to be opened when the working temperature of the EGR valve body accords with a second preset temperature interval, and otherwise, the EGR valve is not allowed to be opened.

2. The EGR valve control method of an engine according to claim 1, characterized in that: the first preset temperature interval in the step I is 20-30 ℃, and the second preset temperature interval in the step I is 120-300 ℃.

3. The EGR valve control method of an engine according to claim 1, characterized in that: and D, acquiring the flow area according to the opening of the throttle valve, and determining the pressure ratio according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve.

4. The EGR valve control method of an engine according to claim 1, characterized in that: and E, determining the pressure ratio according to the dependent variable and a first data table, wherein the first data table is used for recording the mapping relation between the pressure ratio and the dependent variable, and the pressure ratio is an independent variable of a pressure ratio function.

5. The EGR valve control method of an engine according to claim 1, characterized in that: and in the step F, the opening degree of the EGR valve is controlled according to the opening degree value, wherein the second data table is used for recording the mapping relation between the estimated pressure value at the downstream of the EGR valve and the opening degree value of the EGR valve.

6. The EGR valve control method of an engine according to claim 1, characterized in that: the reference EGR rate in step H is a value ranging from 20% to 30%, and the reference EGR rate in step H is generally 25%.

Technical Field

The invention relates to the technical field of EGR valves, in particular to an EGR valve control method of an engine.

Background

The EGR valve is a mechatronic product which is installed on a diesel engine and is used for controlling the exhaust gas recirculation quantity fed back to an air inlet system, is usually positioned on the right side of an air inlet manifold, is close to a throttle body, and is connected with a short metal pipe leading to an exhaust manifold, and has the function of controlling the quantity of the exhaust gas entering the air inlet manifold so as to lead a certain quantity of the exhaust gas to flow into the air inlet manifold for recirculation.

Disclosure of Invention

The invention aims to provide an EGR valve control method of an engine, which has the advantage of being capable of adjusting the opening of an EGR valve and solves the problem of poor control effect of the traditional engine EGR valve.

In order to achieve the purpose, the invention provides the following technical scheme: an EGR valve control method of an engine, the control method comprising the steps of:

A. calculating a required amount of recirculated exhaust gas by an EGR valve controller;

B. the method comprises the steps that a first pressure value of a second pipeline of the engine is obtained through an EGR valve controller, the first pressure value is compared with a first preset value, when the first pressure value is not smaller than the first preset value, a second pressure value of the downstream of an air filter is obtained, the second pressure value is recorded as an estimated pressure value of the downstream of the EGR valve, when the first pressure value is smaller than the first preset value, a pressure ratio and a pressure value of the upstream of a throttle valve are determined, the pressure value of the downstream of the throttle valve is determined according to the pressure ratio and the pressure value of the upstream of the throttle valve, the pressure value of the downstream of the throttle valve is recorded as the estimated pressure value of the downstream;

C. when the first pressure value is not smaller than the first preset value, acquiring a second pressure value at the downstream of the air filter, recording the second pressure value as an estimated pressure value at the downstream of the EGR valve, when the first pressure value is not smaller than the first preset value, determining that the engine is in a first operation working condition, when the engine is in the first operation working condition, controlling the opening of the throttle valve to be the maximum opening, acquiring the second pressure value at the downstream of the air filter, and recording the second pressure value as the estimated pressure value at the downstream of the EGR valve;

D. when the first pressure value is smaller than a first preset value, determining a pressure ratio and a pressure value at the upstream of the throttle valve, and acquiring the opening of the throttle valve, the pressure value at the upstream of the throttle valve and the air flow passing through the throttle valve;

E. determining a pressure ratio according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, determining a pressure ratio function relation according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, and calculating a dependent variable of a pressure ratio function;

F. controlling the opening degree of the EGR valve according to the estimated pressure value at the downstream of the EGR valve, and acquiring the opening degree value of the EGR valve according to the estimated pressure value at the downstream of the EGR valve and a second data table;

G. adjusting the opening degree of the EGR valve so that the opening degree of the EGR valve becomes the second EGR valve opening degree by increasing the opening degree of the EGR valve by a predetermined increase amount from the first EGR valve opening degree when the temperature of the exhaust gas discharged from the combustion chamber exceeds a predetermined reference temperature;

H. determining whether the EGR rate exceeds a reference EGR rate, and adjusting and reducing the EGR valve opening degree so that the EGR rate becomes equal to or less than the set reference EGR rate in a state of being adjusted to the second EGR valve opening degree;

I. the temperature when the engine is started is obtained through the EGR valve controller, the EGR valve is allowed to be opened when the engine starting temperature accords with a first preset temperature interval, otherwise, the EGR valve is not allowed to be opened, the working temperature of the EGR valve body is calculated, the EGR valve is allowed to be opened when the working temperature of the EGR valve body accords with a second preset temperature interval, and otherwise, the EGR valve is not allowed to be opened.

Preferably, the first preset temperature interval in the step I is 20 ℃ to 30 ℃, and the second preset temperature interval in the step I is 120 ℃ to 300 ℃.

Preferably, in the step D, a flow area is obtained according to an opening degree of the throttle valve, and a pressure ratio is determined according to the flow area, a pressure value upstream of the throttle valve, and an air flow passing through the throttle valve.

Preferably, in the step E, the pressure ratio is determined according to the dependent variable and a first data table, where the first data table is used to record a mapping relationship between the pressure ratio and the dependent variable, and the pressure ratio is an independent variable of the pressure ratio function.

Preferably, in the step F, the opening degree of the EGR valve is controlled according to the opening degree value, wherein the second data table is used for recording a mapping relation between the predicted pressure value downstream of the EGR valve and the opening degree value of the EGR valve.

Preferably, the reference EGR rate in step H is a value ranging from 20% to 30%, and the reference EGR rate in step H is generally 25%.

Compared with the prior art, the invention has the following beneficial effects:

the EGR valve disclosed by the invention can be used for realizing the purpose of adjusting the opening degree of the EGR valve, and adjusting the opening degree of the EGR valve according to the working state of an engine, so that the circulation quantity of waste gas is controlled in real time, the requirements of the current market are met, the practicability and usability of the EGR valve of the engine are improved, and the problem of poor control effect of the EGR valve of the engine in the past is solved.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

An EGR valve control method of an engine, the control method comprising the steps of:

A. calculating a required amount of recirculated exhaust gas by an EGR valve controller;

B. the method comprises the steps that a first pressure value of a second pipeline of the engine is obtained through an EGR valve controller, the first pressure value is compared with a first preset value, when the first pressure value is not smaller than the first preset value, a second pressure value of the downstream of an air filter is obtained, the second pressure value is recorded as an estimated pressure value of the downstream of the EGR valve, when the first pressure value is smaller than the first preset value, a pressure ratio and a pressure value of the upstream of a throttle valve are determined, the pressure value of the downstream of the throttle valve is determined according to the pressure ratio and the pressure value of the upstream of the throttle valve, the pressure value of the downstream of the throttle valve is recorded as the estimated pressure value of the downstream;

C. when the first pressure value is not smaller than the first preset value, acquiring a second pressure value at the downstream of the air filter, recording the second pressure value as an estimated pressure value at the downstream of the EGR valve, when the first pressure value is not smaller than the first preset value, determining that the engine is in a first operation working condition, when the engine is in the first operation working condition, controlling the opening of the throttle valve to be the maximum opening, acquiring the second pressure value at the downstream of the air filter, and recording the second pressure value as the estimated pressure value at the downstream of the EGR valve;

D. when the first pressure value is smaller than a first preset value, determining a pressure ratio and a pressure value at the upstream of the throttle valve, and acquiring the opening of the throttle valve, the pressure value at the upstream of the throttle valve and the air flow passing through the throttle valve;

E. determining a pressure ratio according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, determining a pressure ratio function relation according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, and calculating a dependent variable of a pressure ratio function;

F. controlling the opening degree of the EGR valve according to the estimated pressure value at the downstream of the EGR valve, and acquiring the opening degree value of the EGR valve according to the estimated pressure value at the downstream of the EGR valve and a second data table;

G. adjusting the opening degree of the EGR valve so that the opening degree of the EGR valve becomes the second EGR valve opening degree by increasing the opening degree of the EGR valve by a predetermined increase amount from the first EGR valve opening degree when the temperature of the exhaust gas discharged from the combustion chamber exceeds a predetermined reference temperature;

H. determining whether the EGR rate exceeds a reference EGR rate, and adjusting and reducing the EGR valve opening degree so that the EGR rate becomes equal to or less than the set reference EGR rate in a state of being adjusted to the second EGR valve opening degree;

I. the temperature when the engine is started is obtained through the EGR valve controller, the EGR valve is allowed to be opened when the engine starting temperature accords with a first preset temperature interval, otherwise, the EGR valve is not allowed to be opened, the working temperature of the EGR valve body is calculated, the EGR valve is allowed to be opened when the working temperature of the EGR valve body accords with a second preset temperature interval, and otherwise, the EGR valve is not allowed to be opened.

Example 1

An EGR valve control method of an engine, the control method comprising the steps of:

A. calculating a required amount of recirculated exhaust gas by an EGR valve controller;

B. the method comprises the steps that a first pressure value of a second pipeline of the engine is obtained through an EGR valve controller, the first pressure value is compared with a first preset value, when the first pressure value is not smaller than the first preset value, a second pressure value of the downstream of an air filter is obtained, the second pressure value is recorded as an estimated pressure value of the downstream of the EGR valve, when the first pressure value is smaller than the first preset value, a pressure ratio and a pressure value of the upstream of a throttle valve are determined, the pressure value of the downstream of the throttle valve is determined according to the pressure ratio and the pressure value of the upstream of the throttle valve, the pressure value of the downstream of the throttle valve is recorded as the estimated pressure value of the downstream;

C. when the first pressure value is not smaller than the first preset value, acquiring a second pressure value at the downstream of the air filter, recording the second pressure value as an estimated pressure value at the downstream of the EGR valve, when the first pressure value is not smaller than the first preset value, determining that the engine is in a first operation working condition, when the engine is in the first operation working condition, controlling the opening of the throttle valve to be the maximum opening, acquiring the second pressure value at the downstream of the air filter, and recording the second pressure value as the estimated pressure value at the downstream of the EGR valve;

D. when the first pressure value is smaller than a first preset value, determining a pressure ratio and a pressure value at the upstream of the throttle valve, and acquiring the opening of the throttle valve, the pressure value at the upstream of the throttle valve and the air flow passing through the throttle valve;

E. determining a pressure ratio according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, determining a pressure ratio function relation according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, and calculating a dependent variable of a pressure ratio function;

F. controlling the opening degree of the EGR valve according to the estimated pressure value at the downstream of the EGR valve, and acquiring the opening degree value of the EGR valve according to the estimated pressure value at the downstream of the EGR valve and a second data table;

G. adjusting the opening degree of the EGR valve so that the opening degree of the EGR valve becomes the second EGR valve opening degree by increasing the opening degree of the EGR valve by a predetermined increase amount from the first EGR valve opening degree when the temperature of the exhaust gas discharged from the combustion chamber exceeds a predetermined reference temperature;

H. determining whether the EGR rate exceeds a reference EGR rate, and adjusting and reducing the EGR valve opening degree so that the EGR rate becomes equal to or less than the set reference EGR rate in a state of being adjusted to the second EGR valve opening degree;

I. the temperature when the engine is started is obtained through the EGR valve controller, the EGR valve is allowed to be opened when the engine starting temperature accords with a first preset temperature interval, otherwise, the EGR valve is not allowed to be opened, the working temperature of the EGR valve body is calculated, the EGR valve is allowed to be opened when the working temperature of the EGR valve body accords with a second preset temperature interval, and otherwise, the EGR valve is not allowed to be opened.

Example 2

In example 1, the following additional steps were added:

the first preset temperature interval in the step I is 20-30 ℃, and the second preset temperature interval in the step I is 120-300 ℃.

An EGR valve control method of an engine, the control method comprising the steps of:

A. calculating a required amount of recirculated exhaust gas by an EGR valve controller;

B. the method comprises the steps that a first pressure value of a second pipeline of the engine is obtained through an EGR valve controller, the first pressure value is compared with a first preset value, when the first pressure value is not smaller than the first preset value, a second pressure value of the downstream of an air filter is obtained, the second pressure value is recorded as an estimated pressure value of the downstream of the EGR valve, when the first pressure value is smaller than the first preset value, a pressure ratio and a pressure value of the upstream of a throttle valve are determined, the pressure value of the downstream of the throttle valve is determined according to the pressure ratio and the pressure value of the upstream of the throttle valve, the pressure value of the downstream of the throttle valve is recorded as the estimated pressure value of the downstream;

C. when the first pressure value is not smaller than the first preset value, acquiring a second pressure value at the downstream of the air filter, recording the second pressure value as an estimated pressure value at the downstream of the EGR valve, when the first pressure value is not smaller than the first preset value, determining that the engine is in a first operation working condition, when the engine is in the first operation working condition, controlling the opening of the throttle valve to be the maximum opening, acquiring the second pressure value at the downstream of the air filter, and recording the second pressure value as the estimated pressure value at the downstream of the EGR valve;

D. when the first pressure value is smaller than a first preset value, determining a pressure ratio and a pressure value at the upstream of the throttle valve, and acquiring the opening of the throttle valve, the pressure value at the upstream of the throttle valve and the air flow passing through the throttle valve;

E. determining a pressure ratio according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, determining a pressure ratio function relation according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, and calculating a dependent variable of a pressure ratio function;

F. controlling the opening degree of the EGR valve according to the estimated pressure value at the downstream of the EGR valve, and acquiring the opening degree value of the EGR valve according to the estimated pressure value at the downstream of the EGR valve and a second data table;

G. adjusting the opening degree of the EGR valve so that the opening degree of the EGR valve becomes the second EGR valve opening degree by increasing the opening degree of the EGR valve by a predetermined increase amount from the first EGR valve opening degree when the temperature of the exhaust gas discharged from the combustion chamber exceeds a predetermined reference temperature;

H. determining whether the EGR rate exceeds a reference EGR rate, and adjusting and reducing the EGR valve opening degree so that the EGR rate becomes equal to or less than the set reference EGR rate in a state of being adjusted to the second EGR valve opening degree;

I. the temperature when the engine is started is obtained through the EGR valve controller, the EGR valve is allowed to be opened when the engine starting temperature accords with a first preset temperature interval, otherwise, the EGR valve is not allowed to be opened, the working temperature of the EGR valve body is calculated, the EGR valve is allowed to be opened when the working temperature of the EGR valve body accords with a second preset temperature interval, and otherwise, the EGR valve is not allowed to be opened.

Example 3

In example 2, the following steps were added:

and D, acquiring the flow area according to the opening of the throttle valve, and determining the pressure ratio according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve.

An EGR valve control method of an engine, the control method comprising the steps of:

A. calculating a required amount of recirculated exhaust gas by an EGR valve controller;

B. the method comprises the steps that a first pressure value of a second pipeline of the engine is obtained through an EGR valve controller, the first pressure value is compared with a first preset value, when the first pressure value is not smaller than the first preset value, a second pressure value of the downstream of an air filter is obtained, the second pressure value is recorded as an estimated pressure value of the downstream of the EGR valve, when the first pressure value is smaller than the first preset value, a pressure ratio and a pressure value of the upstream of a throttle valve are determined, the pressure value of the downstream of the throttle valve is determined according to the pressure ratio and the pressure value of the upstream of the throttle valve, the pressure value of the downstream of the throttle valve is recorded as the estimated pressure value of the downstream;

C. when the first pressure value is not smaller than the first preset value, acquiring a second pressure value at the downstream of the air filter, recording the second pressure value as an estimated pressure value at the downstream of the EGR valve, when the first pressure value is not smaller than the first preset value, determining that the engine is in a first operation working condition, when the engine is in the first operation working condition, controlling the opening of the throttle valve to be the maximum opening, acquiring the second pressure value at the downstream of the air filter, and recording the second pressure value as the estimated pressure value at the downstream of the EGR valve;

D. when the first pressure value is smaller than a first preset value, determining a pressure ratio and a pressure value at the upstream of the throttle valve, and acquiring the opening of the throttle valve, the pressure value at the upstream of the throttle valve and the air flow passing through the throttle valve;

E. determining a pressure ratio according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, determining a pressure ratio function relation according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, and calculating a dependent variable of a pressure ratio function;

F. controlling the opening degree of the EGR valve according to the estimated pressure value at the downstream of the EGR valve, and acquiring the opening degree value of the EGR valve according to the estimated pressure value at the downstream of the EGR valve and a second data table;

G. adjusting the opening degree of the EGR valve so that the opening degree of the EGR valve becomes the second EGR valve opening degree by increasing the opening degree of the EGR valve by a predetermined increase amount from the first EGR valve opening degree when the temperature of the exhaust gas discharged from the combustion chamber exceeds a predetermined reference temperature;

H. determining whether the EGR rate exceeds a reference EGR rate, and adjusting and reducing the EGR valve opening degree so that the EGR rate becomes equal to or less than the set reference EGR rate in a state of being adjusted to the second EGR valve opening degree;

I. the temperature when the engine is started is obtained through the EGR valve controller, the EGR valve is allowed to be opened when the engine starting temperature accords with a first preset temperature interval, otherwise, the EGR valve is not allowed to be opened, the working temperature of the EGR valve body is calculated, the EGR valve is allowed to be opened when the working temperature of the EGR valve body accords with a second preset temperature interval, and otherwise, the EGR valve is not allowed to be opened.

Example 4

In example 3, the following steps were added:

and E, determining the pressure ratio according to the dependent variable and a first data table, wherein the first data table is used for recording the mapping relation between the pressure ratio and the dependent variable, and the pressure ratio is an independent variable of a pressure ratio function.

An EGR valve control method of an engine, the control method comprising the steps of:

A. calculating a required amount of recirculated exhaust gas by an EGR valve controller;

B. the method comprises the steps that a first pressure value of a second pipeline of the engine is obtained through an EGR valve controller, the first pressure value is compared with a first preset value, when the first pressure value is not smaller than the first preset value, a second pressure value of the downstream of an air filter is obtained, the second pressure value is recorded as an estimated pressure value of the downstream of the EGR valve, when the first pressure value is smaller than the first preset value, a pressure ratio and a pressure value of the upstream of a throttle valve are determined, the pressure value of the downstream of the throttle valve is determined according to the pressure ratio and the pressure value of the upstream of the throttle valve, the pressure value of the downstream of the throttle valve is recorded as the estimated pressure value of the downstream;

C. when the first pressure value is not smaller than the first preset value, acquiring a second pressure value at the downstream of the air filter, recording the second pressure value as an estimated pressure value at the downstream of the EGR valve, when the first pressure value is not smaller than the first preset value, determining that the engine is in a first operation working condition, when the engine is in the first operation working condition, controlling the opening of the throttle valve to be the maximum opening, acquiring the second pressure value at the downstream of the air filter, and recording the second pressure value as the estimated pressure value at the downstream of the EGR valve;

D. when the first pressure value is smaller than a first preset value, determining a pressure ratio and a pressure value at the upstream of the throttle valve, and acquiring the opening of the throttle valve, the pressure value at the upstream of the throttle valve and the air flow passing through the throttle valve;

E. determining a pressure ratio according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, determining a pressure ratio function relation according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, and calculating a dependent variable of a pressure ratio function;

F. controlling the opening degree of the EGR valve according to the estimated pressure value at the downstream of the EGR valve, and acquiring the opening degree value of the EGR valve according to the estimated pressure value at the downstream of the EGR valve and a second data table;

G. adjusting the opening degree of the EGR valve so that the opening degree of the EGR valve becomes the second EGR valve opening degree by increasing the opening degree of the EGR valve by a predetermined increase amount from the first EGR valve opening degree when the temperature of the exhaust gas discharged from the combustion chamber exceeds a predetermined reference temperature;

H. determining whether the EGR rate exceeds a reference EGR rate, and adjusting and reducing the EGR valve opening degree so that the EGR rate becomes equal to or less than the set reference EGR rate in a state of being adjusted to the second EGR valve opening degree;

I. the temperature when the engine is started is obtained through the EGR valve controller, the EGR valve is allowed to be opened when the engine starting temperature accords with a first preset temperature interval, otherwise, the EGR valve is not allowed to be opened, the working temperature of the EGR valve body is calculated, the EGR valve is allowed to be opened when the working temperature of the EGR valve body accords with a second preset temperature interval, and otherwise, the EGR valve is not allowed to be opened.

Example 5

In example 4, the following steps were added:

and F, controlling the opening degree of the EGR valve according to the opening degree value, wherein the second data table is used for recording the mapping relation between the estimated pressure value at the downstream of the EGR valve and the opening degree value of the EGR valve.

An EGR valve control method of an engine, the control method comprising the steps of:

A. calculating a required amount of recirculated exhaust gas by an EGR valve controller;

B. the method comprises the steps that a first pressure value of a second pipeline of the engine is obtained through an EGR valve controller, the first pressure value is compared with a first preset value, when the first pressure value is not smaller than the first preset value, a second pressure value of the downstream of an air filter is obtained, the second pressure value is recorded as an estimated pressure value of the downstream of the EGR valve, when the first pressure value is smaller than the first preset value, a pressure ratio and a pressure value of the upstream of a throttle valve are determined, the pressure value of the downstream of the throttle valve is determined according to the pressure ratio and the pressure value of the upstream of the throttle valve, the pressure value of the downstream of the throttle valve is recorded as the estimated pressure value of the downstream;

C. when the first pressure value is not smaller than the first preset value, acquiring a second pressure value at the downstream of the air filter, recording the second pressure value as an estimated pressure value at the downstream of the EGR valve, when the first pressure value is not smaller than the first preset value, determining that the engine is in a first operation working condition, when the engine is in the first operation working condition, controlling the opening of the throttle valve to be the maximum opening, acquiring the second pressure value at the downstream of the air filter, and recording the second pressure value as the estimated pressure value at the downstream of the EGR valve;

D. when the first pressure value is smaller than a first preset value, determining a pressure ratio and a pressure value at the upstream of the throttle valve, and acquiring the opening of the throttle valve, the pressure value at the upstream of the throttle valve and the air flow passing through the throttle valve;

E. determining a pressure ratio according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, determining a pressure ratio function relation according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, and calculating a dependent variable of a pressure ratio function;

F. controlling the opening degree of the EGR valve according to the estimated pressure value at the downstream of the EGR valve, and acquiring the opening degree value of the EGR valve according to the estimated pressure value at the downstream of the EGR valve and a second data table;

G. adjusting the opening degree of the EGR valve so that the opening degree of the EGR valve becomes the second EGR valve opening degree by increasing the opening degree of the EGR valve by a predetermined increase amount from the first EGR valve opening degree when the temperature of the exhaust gas discharged from the combustion chamber exceeds a predetermined reference temperature;

H. determining whether the EGR rate exceeds a reference EGR rate, and adjusting and reducing the EGR valve opening degree so that the EGR rate becomes equal to or less than the set reference EGR rate in a state of being adjusted to the second EGR valve opening degree;

I. the temperature when the engine is started is obtained through the EGR valve controller, the EGR valve is allowed to be opened when the engine starting temperature accords with a first preset temperature interval, otherwise, the EGR valve is not allowed to be opened, the working temperature of the EGR valve body is calculated, the EGR valve is allowed to be opened when the working temperature of the EGR valve body accords with a second preset temperature interval, and otherwise, the EGR valve is not allowed to be opened.

Example 6

In example 5, the following steps were added:

the reference EGR rate in step H is a value ranging from 20% to 30%, and the reference EGR rate in step H is generally 25%.

An EGR valve control method of an engine, the control method comprising the steps of:

A. calculating a required amount of recirculated exhaust gas by an EGR valve controller;

B. the method comprises the steps that a first pressure value of a second pipeline of the engine is obtained through an EGR valve controller, the first pressure value is compared with a first preset value, when the first pressure value is not smaller than the first preset value, a second pressure value of the downstream of an air filter is obtained, the second pressure value is recorded as an estimated pressure value of the downstream of the EGR valve, when the first pressure value is smaller than the first preset value, a pressure ratio and a pressure value of the upstream of a throttle valve are determined, the pressure value of the downstream of the throttle valve is determined according to the pressure ratio and the pressure value of the upstream of the throttle valve, the pressure value of the downstream of the throttle valve is recorded as the estimated pressure value of the downstream;

C. when the first pressure value is not smaller than the first preset value, acquiring a second pressure value at the downstream of the air filter, recording the second pressure value as an estimated pressure value at the downstream of the EGR valve, when the first pressure value is not smaller than the first preset value, determining that the engine is in a first operation working condition, when the engine is in the first operation working condition, controlling the opening of the throttle valve to be the maximum opening, acquiring the second pressure value at the downstream of the air filter, and recording the second pressure value as the estimated pressure value at the downstream of the EGR valve;

D. when the first pressure value is smaller than a first preset value, determining a pressure ratio and a pressure value at the upstream of the throttle valve, and acquiring the opening of the throttle valve, the pressure value at the upstream of the throttle valve and the air flow passing through the throttle valve;

E. determining a pressure ratio according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, determining a pressure ratio function relation according to the flow area, the upstream pressure value of the throttle valve and the air flow passing through the throttle valve, and calculating a dependent variable of a pressure ratio function;

F. controlling the opening degree of the EGR valve according to the estimated pressure value at the downstream of the EGR valve, and acquiring the opening degree value of the EGR valve according to the estimated pressure value at the downstream of the EGR valve and a second data table;

G. adjusting the opening degree of the EGR valve so that the opening degree of the EGR valve becomes the second EGR valve opening degree by increasing the opening degree of the EGR valve by a predetermined increase amount from the first EGR valve opening degree when the temperature of the exhaust gas discharged from the combustion chamber exceeds a predetermined reference temperature;

H. determining whether the EGR rate exceeds a reference EGR rate, and adjusting and reducing the EGR valve opening degree so that the EGR rate becomes equal to or less than the set reference EGR rate in a state of being adjusted to the second EGR valve opening degree;

I. the temperature when the engine is started is obtained through the EGR valve controller, the EGR valve is allowed to be opened when the engine starting temperature accords with a first preset temperature interval, otherwise, the EGR valve is not allowed to be opened, the working temperature of the EGR valve body is calculated, the EGR valve is allowed to be opened when the working temperature of the EGR valve body accords with a second preset temperature interval, and otherwise, the EGR valve is not allowed to be opened.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.