阅读说明：本技术 一种防止egr系统结冰的控制方法 (Control method for preventing EGR system from freezing ) 是由 韦钻国 刘志治 宁德忠 谭宗慧 于 2020-03-31 设计创作，主要内容包括：本发明公开了一种防止EGR系统结冰的控制方法,涉及EGR系统,解决现有EGR系统结冰的技术问题,该方法包括：S1.获取整车怠速时间、进气总管内混合气温度和环境温度；S2.若进气总管内混合气温度低于第一标定温度值且环境温度低于第二标定温度值且整车怠速时间超过第一标定时间值,则跳转到步骤S3；否则返回步骤S1；S3.获取整车的操作状态,若整车无相应的操作,则跳转到步骤S4；否则返回步骤S1；S4.提高发动机转速和负荷,使EGR阀开启,发动机废气通过混合器与冷空气混合,直到进气总管内混合气温度高于第三标定温度值；S5.延时第二标定时间值后恢复整车正常的怠速工况,并返回步骤S1。本发明可以有效降低EGR系统结冰导致的无法启动或者熄火的安全隐患。(The invention discloses a control method for preventing an EGR (exhaust gas recirculation) system from being frozen, relates to the EGR system, and solves the technical problem of freezing of the existing EGR system, and the method comprises the following steps: s1, acquiring the idle time of a whole vehicle, the temperature of mixed gas in an air inlet main pipe and the ambient temperature; s2, if the temperature of mixed gas in the air inlet main pipe is lower than a first calibration temperature value, the ambient temperature is lower than a second calibration temperature value and the idling time of the whole vehicle exceeds a first calibration time value, jumping to the step S3; otherwise, returning to the step S1; s3, acquiring the operation state of the whole vehicle, and if the whole vehicle has no corresponding operation, jumping to the step S4; otherwise, returning to the step S1; s4, increasing the rotating speed and the load of the engine to open the EGR valve, and mixing the engine exhaust gas with cold air through a mixer until the temperature of mixed gas in the air inlet main pipe is higher than a third calibrated temperature value; and S5, recovering the normal idling working condition of the whole vehicle after delaying the second calibration time value, and returning to the step S1. The method can effectively reduce the potential safety hazard that the EGR system cannot be started or shut down due to icing.)

1. A control method for preventing EGR system icing, the method comprising the steps of:

s1, acquiring the idle time of a whole vehicle, the temperature of mixed gas in an air inlet main pipe and the ambient temperature;

s2, if the temperature of mixed gas in the air inlet main pipe is lower than a first calibration temperature value, the ambient temperature is lower than a second calibration temperature value and the idling time of the whole vehicle exceeds a first calibration time value, jumping to the step S3; otherwise, returning to the step S1;

s3, acquiring the operation state of the whole vehicle, and if the whole vehicle has no corresponding operation, jumping to the step S4; otherwise, returning to the step S1;

s4, increasing the rotating speed and the load of the engine, enabling the EGR valve to be opened according to the EGR rate target, and enabling the exhaust gas of the engine to be mixed with cold air through a mixer until the temperature of the mixed gas in the air inlet main pipe is higher than a third calibrated temperature value;

and S5, recovering the normal idling working condition of the whole vehicle after delaying the second calibration time value, and returning to the step S1.

2. The control method of claim 1, wherein the corresponding operation comprises at least one of a throttle signal, a brake signal, a clutch signal, and a PTO signal.

3. The control method for preventing the EGR system from being frozen as claimed in claim 1, wherein when the step S4 is skipped, the user is reminded that the EGR system is running the anti-freezing function.

4. The control method for preventing the EGR system from being frozen according to claim 1, wherein the first calibrated temperature value is 0-5 ℃.

5. The control method for preventing the EGR system from being frozen according to claim 1, wherein the second calibrated temperature value is 0-5 ℃.

6. The control method for preventing the EGR system from being frozen according to claim 1, wherein the third calibrated temperature value is 20-25 ℃.

7. The control method for preventing the EGR system from being frozen according to claim 1, wherein the first calibration time value is 10-15 min.

8. The control method for preventing the EGR system from being frozen according to claim 1, wherein the second calibration time value is 3-5 min.

9. The control method for preventing the EGR system from being frozen according to any one of claims 1-8, characterized in that the temperature of the mixed gas in the intake manifold and the ambient temperature are respectively obtained through a temperature pressure sensor and an engine ambient temperature sensor which are arranged on an engine intake pipe, the engine ECU is used for increasing the engine speed and the engine load, and the EGR valve is opened according to the EGR rate target.

Technical Field

The present invention relates to EGR systems, and more particularly, it relates to a control method for preventing EGR systems from freezing.

Background

In order to meet the national six-emission regulations, the internal combustion engine adopts a technical route of equivalent combustion, but because the combustion temperature in a cylinder is higher in the technical route, EGR (exhaust gas recirculation) gas must be introduced to reduce the combustion temperature in the cylinder and improve the reliability of the engine. EGR gas composition consisting mainly of CO₂And H₂O composition wherein H₂O is present mainly in gaseous form. Since the EGR valve is physically constructed as a poppet valve, the valve plate and valve seat cannot be completely sealed, and there is a slight leakage in the closed state. In cold regions, when there is a slight leak in the EGR valve, the gas enters the EGR mixer to mix with fresh air, because the temperature of the air is low, and the moisture in the EGR condenses into water upon condensation. Under a small-load working condition, particularly a long-time idling working condition, condensed water cannot be brought into a cylinder due to small air flow in the EGR, so that the condensed water is attached to an EGR mixer to form ice. Along with the accumulation of the icing amount, the EGR mixer can be blocked, so that air cannot enter a cylinder through the mixer to be combusted, the power of an engine is insufficient or the engine is in flameout failure, and the driving safety is influenced.

The mainstream internal combustion engine control system adopting the EGR technology for the current six gas engines is shown in FIG. 1. A portion of the exhaust gas combusted from the engine cylinder a passes through the EGR cooler B and the EGR valve C into the mixer D. The main problems of the current mainstream EGR (exhaust gas recirculation) control system are:

the ECU can calculate the opening degree of the EGR valve according to the EGR rate target under different working conditions, and when the engine is in a small load or idling working condition, because the combustion stability of the small load and the idling working condition is poor, if the EGR is introduced, the problems of unstable combustion, rotation speed fluctuation and the like can be caused. The EGR rate target for the low load or idle condition is generally set to 0, and therefore the EGR valve opening degree is 0. Under the condition of cold weather, a driver usually uses warm air for heating under an in-situ idling working condition in the process of waiting for loading and unloading goods, if the EGR valve has slight leakage, the hot combustion exhaust gas in the exhaust gas pipeline behind the EGR cooler B, the EGR valve C and the connecting pipeline of the mixer D is more easily frozen under the long-time condition, and a series of fault conditions such as flameout or incapability of starting the engine in the running process are caused.

Disclosure of Invention

The present invention is directed to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a control method capable of effectively preventing an EGR system from being frozen.

The technical scheme of the invention is as follows: a control method of preventing EGR system icing, the method comprising:

s1, acquiring the idle time of a whole vehicle, the temperature of mixed gas in an air inlet main pipe and the ambient temperature;

s2, if the temperature of mixed gas in the air inlet main pipe is lower than a first calibration temperature value, the ambient temperature is lower than a second calibration temperature value and the idling time of the whole vehicle exceeds a first calibration time value, jumping to the step S3; otherwise, returning to the step S1;

s3, acquiring the operation state of the whole vehicle, and if the whole vehicle has no corresponding operation, jumping to the step S4; otherwise, returning to the step S1;

s4, increasing the rotating speed and the load of the engine, enabling the EGR valve to be opened according to the EGR rate target, and enabling the exhaust gas of the engine to be mixed with cold air through a mixer until the temperature of the mixed gas in the air inlet main pipe is higher than a third calibrated temperature value;

and S5, recovering the normal idling working condition of the whole vehicle after delaying the second calibration time value, and returning to the step S1.

As a further improvement, the corresponding operation includes at least one of a throttle signal, a brake signal, a clutch signal, and a PTO signal.

Further, when the step S4 is skipped, the user is reminded that the EGR system is operating the anti-icing function.

Further, the first calibration temperature value is 0-5 ℃.

Further, the second calibration temperature value is 0-5 ℃.

Further, the third calibration temperature value is 20-25 ℃.

Further, the first calibration time value is 10-15 min.

Further, the second calibration time value is 3-5 min.

Further, the temperature and the ambient temperature of mixed gas in the air inlet manifold are obtained through a temperature pressure sensor and an engine ambient temperature sensor which are arranged on an engine air inlet pipe, the rotating speed and the load of the engine are improved through an engine ECU, and the EGR valve is opened according to an EGR rate target.

Advantageous effects

Compared with the prior art, the invention has the advantages that: according to the invention, by acquiring the idling time of the whole vehicle, the temperature of the mixed gas in the air inlet main pipe and the ambient temperature, when the temperature of the mixed gas in the air inlet main pipe is lower than a first calibration temperature value, the ambient temperature is lower than a second calibration temperature value and the idling time of the whole vehicle exceeds a first calibration time value, the rotating speed and the load of the engine are increased, the EGR valve is opened according to an EGR rate target, the exhaust gas of the engine is mixed with cold air through the mixer until the temperature of the mixed gas in the air inlet main pipe is higher than a third calibration temperature value, the normal idling working condition of the whole vehicle is recovered after the second calibration time value is delayed, the potential safety hazard that the EGR system cannot be started or shut down due to icing can be effectively reduced by repeating the actions, and the. The invention can achieve the anti-icing effect of the EGR system only by optimizing the application program without increasing the cost of parts, thereby saving the cost and being easy to popularize.

Drawings

FIG. 1 is a schematic diagram of a prior art structure;

fig. 2 is a schematic diagram of a control structure of the present invention.

Wherein: 1-engine, 2-exhaust manifold, 3-EGR gas pipe, 4-EGR cooler, 5-EGR valve, 6-mixer, 7-temperature pressure sensor, 8-intake pipe and 9-environment temperature sensor.

Detailed Description

The invention will be further described with reference to specific embodiments shown in the drawings.

Referring to fig. 2, a portion of exhaust gas discharged from the engine 1 into the exhaust manifold 2 passes through the EGR pipe 3, sequentially passes through the EGR cooler 4, the EGR valve 5, and reaches the mixer 6, and the exhaust gas is mixed with cool air in the mixer 6 and then enters the engine 1 through the intake pipe 8.

A control method for preventing EGR system icing, the method comprising the steps of:

s1, an engine ECU acquires the idling time of a whole vehicle, the engine ECU acquires the temperature of mixed gas in an air inlet main pipe through a temperature and pressure sensor 7 arranged on an air inlet pipe 8 of the engine, and the engine ECU acquires the ambient temperature through an engine ambient temperature sensor 9;

s2, if the temperature of mixed gas in the air inlet main pipe is lower than a first calibration temperature value, the ambient temperature is lower than a second calibration temperature value and the idling time of the whole vehicle exceeds a first calibration time value, jumping to the step S3; otherwise, returning to the step S1;

s3, acquiring the operation state of the whole vehicle, and if the whole vehicle has no corresponding operation, jumping to the step S4; otherwise, returning to the step S1;

s4, the engine ECU increases the engine speed and load, so that the EGR valve 5 is opened according to the EGR rate target, and the engine exhaust gas is mixed with cold air through the mixer 6 until the temperature of the mixed gas in the air inlet manifold is higher than a third calibrated temperature value, thereby effectively preventing icing or deicing;

and S5, recovering the normal idling working condition of the whole vehicle after delaying the second calibration time value, and returning to the step S1.

The corresponding operation comprises at least one of an accelerator signal, a brake signal, a clutch signal and a PTO signal, and the steps S4 and S5 can be executed to prevent icing only when the whole vehicle does not perform the operation.

When the step S4 is skipped, the engine ECU sends out a reminding message to remind the user that the EGR system is running the anti-icing function, so that the user is informed that the function is normal when the function is started, and the anti-icing function is not necessary to be panic and to be operated.

The specific values of the first calibration temperature value, the second calibration temperature value, the third calibration temperature value, the first calibration time value and the second calibration time value can be set according to specific vehicle types or specific working environments. In this embodiment, the first calibration temperature value is 0-5 ℃, the second calibration temperature value is 0-5 ℃, the third calibration temperature value is 20-25 ℃, the first calibration time value is 10-15 min, and the second calibration time value is 3-5 min.

According to the invention, by acquiring the idling time of the whole vehicle, the temperature of the mixed gas in the air inlet main pipe and the ambient temperature, when the temperature of the mixed gas in the air inlet main pipe is lower than a first calibration temperature value, the ambient temperature is lower than a second calibration temperature value and the idling time of the whole vehicle exceeds a first calibration time value, the rotating speed and the load of the engine are increased, the EGR valve is opened according to an EGR rate target, the exhaust gas of the engine is mixed with cold air through the mixer until the temperature of the mixed gas in the air inlet main pipe is higher than a third calibration temperature value, the normal idling working condition of the whole vehicle is recovered after the second calibration time value is delayed, the potential safety hazard that the EGR system cannot be started or shut down due to icing can be effectively reduced by repeating the actions, and the. The invention can achieve the anti-icing effect of the EGR system only by optimizing the application program without increasing the cost of parts, thereby saving the cost and being easy to popularize.

The above is only a preferred embodiment of the present invention, and it should be noted that it is obvious to those skilled in the art that several variations and modifications can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the utility of the patent.