KR20140028635A - System and method for learning exhaust gas recirculation of vehicle - Google Patents

Abstract

The present invention provides a flow learning system and method of an exhaust gas recirculation device for a vehicle. The present invention can improve the reliability of a flow learning value of an exhaust gas recirculation device and can maintain the amount of fuel because the present invention judges the flow learning value to be erroneous if the fuel learning value for a previous cycle exceeds a limit value, and conducts flow learning for a current cycle (N) based on a reference value, by judging whether or not the flow learning value of the exhaust gas recirculation device for a previous cycle (N-1) exceeds the predetermined limit value, and conducting the flow learning of the exhaust gas recirculation device for the current cycle (N) based on the predetermined reference value if the judged flow learning value for the previous cycle exceeds the limit value. [Reference numerals] (101) Receive a learning value for a previous cycle (N-1); (103) Learning value > Limit value ?; (105) Judge the invalidity of the learning value for the previous cycle (N-1); (107) Conduct learning for the current cycle (N) based on a stored reference value; (109) Learning value for the current cycle (N) > Limit value ?; (111) Judge and notify the malfunction of an exhaust gas recirculation device; (113) Store the learning value for the current cycle (N) as the learning value for the previous cycle (N-1); (115) Is the learning of the exhaust gas recirculation device ended ?; (121) Conduct learning for the current cycle (N) based on the learning value for the previous cycle (N-1); (AA) Start; (BB) End

Description

Flow Rate Learning System and Method for Vehicle Exhaust Gas Recirculation System {SYSTEM AND METHOD FOR LEARNING EXHAUST GAS RECIRCULATION OF VEHICLE}

The present invention relates to a flow rate learning method of a vehicle exhaust gas recirculation apparatus, and more particularly, when the learning value for the exhaust gas exceeds a preset limit, it is determined that there is no reliability of the learning value for the corresponding period. It relates to a system and method that allows the next cycle of learning to be carried out with reference values.

Typically, most vehicle systems, particularly diesel vehicles, employ an Exhaust Gas Recirculation (EGR) device that has the function of reducing nitrogen oxides (NOx) in the exhaust gases generated by engine driving.

In general, the exhaust gas recirculation apparatus is equipped with an EGR valve at an intermediate position of a pipe connecting the exhaust manifold and the intake manifold, and thus the EGR valve is driven by the pressure difference between both ends and the opening area of the EGR valve, that is, the lift amount due to opening / closing. The amount is configured to be determined.

Such an exhaust gas recirculation (EGR) device performs learning through feedback control to execute learning of the current period N based on the learning value of the previous period N-1, in order to keep the amount of fuel supplied to the engine constant. .

However, when an error occurs in the learning value of the previous period N-1 due to the aging of the vehicle, a calculation error occurring during the learning, or the like, the current execution is performed based on the learning value of the previous period N-1 in which the error occurred. The reliability of the learning value of the period N is lowered.

In addition, when the exhaust gas recirculation device is controlled by the learning value of the current period N, which is less reliable, a fatal problem occurs in the fuel system and the exhaust gas recirculation device of the vehicle including fuel amount control.

Therefore, the present invention was created to solve the above problems, and an object of the present invention is to determine whether the learning value for the exhaust gas recirculation apparatus of the previous period (N-1) exceeds a preset limit, Providing a flow rate learning system and method of the exhaust gas recirculation apparatus provided to perform the learning about the exhaust gas recirculation apparatus for the current period (N) with a preset reference value when the learning value for the previous cycle exceeds the above limit. If the learning value for the previous cycle exceeds the limit, it is determined that the learning value of the previous cycle is not valid and the learning is performed for the current period N with the preset reference value, whereby the learning value for the exhaust gas recirculation apparatus is Improves reliability and keeps fuel level constant.

According to a first aspect of the present invention,

In the flow rate learning device of the exhaust gas recirculation apparatus for monitoring the exhaust gas of the exhaust gas recirculation apparatus at a predetermined period of a predetermined time unit and intermittently EGR amount based on the oxygen saturation included in the monitored exhaust gas,

A learning value validity determining step of determining whether the flow rate learning value for the exhaust gas recirculation device of the previous period N-1 exceeds a preset limit value; And

And a flow rate learning execution step of performing learning on the exhaust gas recirculation device for the current period N with a preset reference value when the flow rate learning value for the previous period determined exceeds the limit.

Preferably, the method further comprises:

Determining whether a flow rate learning value of the exhaust gas recirculation device for the current period N exceeds a preset limit value; And

If the flow rate learning value for the current period (N) exceeds the above limit may further comprise the step of notifying the driver or manufacturer as a failure to the exhaust gas recirculation device.

Preferably, in the learning value validity determination step, when the learning value for the determined previous period does not exceed the limit, storing the flow rate learning value of the current period N as the flow rate learning value of the previous period N-1. It may further comprise a step.

Preferably the limit value of the flow rate learning value validity determination step,

If the reflectance of the flow rate learning value of the previous period (N-1) is 1 during the flow rate learning for the current period (N) may be set to a value greater than the flow rate learning value reflectance of 1.

Preferably the limit value of the flow rate learning value validity determination step,

If the reflectance of the flow rate learning value of the previous period (N-1) is 1 during the flow rate learning execution for the current period (N) may be set to a value smaller than the flow rate learning value reflectance of 1.

Preferably the reference value is

The fuel may be derived based on a predetermined relational expression for the fuel amount, the engine speed, and the intake valve opening amount, and may be stored in advance as interpolation table data corresponding to the fuel amount.

Flow rate learning system of the exhaust gas recirculation apparatus according to the second aspect of the present invention for achieving the above object

engine;

An exhaust gas recirculation device for recycling the exhaust gas of the engine; And

When the flow rate learning condition for the exhaust gas recirculation device is satisfied, the controller includes a control unit for monitoring the exhaust gas of the exhaust gas recirculation device at a predetermined period of a predetermined time unit and controlling the EGR amount based on the oxygen saturation included in the monitored exhaust gas. But

Wherein,

It is determined whether the flow rate learning value for the exhaust gas recirculation device of the previous cycle N-1 exceeds the preset limit, and when the flow rate learning value for the previous cycle exceeds the limit, the current period N as the preset reference value. And perform flow rate learning for the exhaust gas recirculation apparatus for the apparatus.

Preferably, the control unit determines whether the flow rate learning value of the exhaust gas recirculation device for the current period (N) exceeds a preset limit value,

If the flow rate learning value for the current period (N) exceeds the above limit, it is provided to determine that the failure to the exhaust gas recirculation device and to notify the driver or the manufacturer.

Preferably, the controller is configured to store the flow rate learning value of the current period N as the flow rate learning value of the previous period N-1 when the determined flow rate learning value for the previous period does not exceed the limit value. It features.

As described above, according to the flow rate learning system and method of the exhaust gas recirculation apparatus according to the present invention, it is determined whether the flow rate learning value for the exhaust gas recirculation apparatus of the previous period N-1 exceeds the preset limit value. When the flow rate learning value for the previous cycle exceeded the limit value, the flow rate learning value for the previous cycle is set as the flow rate learning for the exhaust gas recirculation device for the current cycle N with the preset reference value. If the flow rate is exceeded, the flow rate learning value is determined as an error, and the reference value is used to perform the flow rate learning for the current period N, thereby improving the reliability of the flow rate learning value for the exhaust gas recirculating apparatus and maintaining the fuel amount constant. Get

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given below, serve to further understand the technical idea of the invention. And should not be construed as limiting.
1 is a block diagram showing a flow rate flow rate learning system of the exhaust gas recirculation apparatus according to a preferred embodiment of the present invention.
2 is a flowchart illustrating a flow rate learning process of the exhaust gas recirculation apparatus according to the preferred embodiment of the present invention.
3 is a view illustrating a flow rate learning value of the exhaust gas recirculation apparatus illustrated in FIG. 1.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

1 is a view showing a flow rate learning system of the exhaust gas recirculation apparatus according to a preferred embodiment of the present invention.

As shown in FIG. 1, the flow rate learning system of the exhaust gas recirculation apparatus according to the present invention includes an engine 10, an exhaust gas recirculation apparatus 20 for recirculating the exhaust gas of the engine 10, and a previous cycle ( It is determined whether the flow rate learning value for the exhaust gas recirculation device of N-1) exceeds the preset limit, and when the flow rate learning value for the previous period exceeds the limit, the exhaust gas for the current period N is set to the preset reference value. And a control unit 30 for performing flow rate learning for the gas recirculation apparatus. Here, N is a natural number of 2 or more.

The engine 10 is a device that generates fuel as a driving force by burning fuel in a cylinder, and includes a cylinder in which fuel is injected and ignited, a piston, a crank, and the like, which are moved by fuel ignition in the cylinder. do.

The exhaust gas recirculation device 20 is a device for recirculating the exhaust gas of the engine 10, and has a function of reducing nitrogen oxides (NOx) in the exhaust gas generated by the engine 10 and lowering the temperature of the combustion chamber. Do this.

The exhaust gas recirculation apparatus 20 is equipped with an EGR valve at an intermediate position of a pipe connecting the exhaust manifold and the intake manifold, so that the pressure difference between both ends and the opening area of the EGR valve, i. The EGR amount is determined by Hereinafter, for convenience of explanation, an exhaust gas recirculation device, that is, an exhaust gas recirculation (EGR) device will be referred to as an EGR device.

The controller 30 determines that the flow rate learning value is not valid when the flow rate learning value of the previous period N is greater than or equal to the preset limit value, and performs flow rate learning for the current period N with the preset reference value.

In more detail, the control unit 30 may control various control signals such as the engine speed and the intake valve opening amount received based on sensing signals received from various sensors for detecting the fuel amount, the vehicle state, and the like of the engine 10. The control unit is provided to various devices in the vehicle, and the control unit 30 may be an electronic control unit (ECU).

That is, when the flow rate learning condition for the exhaust gas recirculation apparatus 20 is satisfied, the controller 30 controls the exhaust gas recirculation apparatus 20 to execute preset flow rate learning.

For example, the controller 30 may determine the driving time of the vehicle in a predetermined time unit based on sensing signals received from various sensors for detecting the state of the engine 10 and the vehicle state. It is determined whether the flow rate learning condition is satisfied on the basis of the engine speed received at a predetermined cycle, the intake pressure of the intake valve, and the fuel amount, and if these conditions are satisfied, the flow rate learning condition for the exhaust gas recirculation device is satisfied.

Then, the controller 30 controls the exhaust gas recirculation apparatus 20 to execute preset flow rate learning.

In other words, the controller 30 reflects the flow rate learning value of the previous period N-1 to execute the flow rate learning in the current period N. FIG. In this case, in general, a series of processes for learning the flow rate for the local cycle N by setting the reflectance ratio of the flow rate learning value of the previous cycle N-1 to 1 is performed by a conventional process that is well known.

However, the controller 30 sets the flow rate learning value reflection rate of the previous period N-1 to a predetermined limit value, and if the flow rate learning value of the previous period N-1 exceeds the limit value, the previous period ( It is determined that the flow rate learning value of N-1) is not effective.

Here, the limit value is set to a value greater than the flow rate learning value reflectivity of 1 when the reflectance rate of the flow rate learning value of the previous period N-1 is 1 during the flow rate learning execution for the current period N. In addition, the limit value is preferably set to a value smaller than the flow rate learning value reflectivity of 1 when the reflectance rate of the flow rate learning value of the previous period (N-1) is 1 during the flow rate learning execution for the current period (N). something to do. At this time, it is generally preferable that the limit value set to a value larger than the flow rate learning value reflectivity of 1 is set to 1.05. It is preferable that the limit value set to a value smaller than the flow rate learning value reflectance ratio of 1 is set to 0.95.

At this time, when the flow rate learning value of the previous period N-1 exceeds the limit value, the controller 30 determines that the flow rate learning value of the previous period N is not valid, and therefore, the flow rate learning value of the current period N is thus determined. The flow rate learning is performed by reflecting the preset reference value.

Here, the reference value is derived based on a predetermined relational expression for the fuel amount, the engine speed, and the intake valve opening amount, and is stored in advance as an interpolation table data corresponding to the fuel amount.

Since a series of processes for deriving a reference value from the relational expressions for the fuel amount, the engine speed, and the intake valve opening amount are provided in the same manner as in the conventional configuration of determining the EGR amount based on the fuel amount, the engine speed, and the intake valve opening amount, Since a detailed description thereof is omitted, and a series of processes for deriving a reference value from the EGR amount are also the same as the conventional process, a detailed description thereof will be omitted.

The reference value is stored in advance as a table value corresponding to the EGR amount.

And the said control part 30 performs flow volume learning with respect to the waste gas recirculation apparatus 20 of the current period N based on said reference value.

When the flow rate learning value of the derived current period N exceeds the limit value, the controller 30 determines that the exhaust gas recirculation apparatus 20 is faulty and then detects a failure of the exhaust gas recirculating body 20. Or notify the manufacturer.

On the other hand, if the derived flow rate learning value of the local period (N) does not exceed the limit value, the controller 30 executes the flow rate learning of the next period (N + 1) based on the current flow rate learning value.

According to this configuration, when the flow rate learning value for the exhaust gas recirculation apparatus 20 of the previous period (N-1) exceeds the preset limit value, the controller 30 determines that the flow rate learning value is not effective. Flow rate learning for the exhaust gas recirculation apparatus 20 of the current period N by reflecting a reference value, which is derived from the engine fuel amount, the engine speed, and the intake valve opening amount, in advance in the flow rate learning value of the local period N. As a result, the reliability of the flow rate learning value for the exhaust gas recirculation device can be improved and the fuel amount can be kept constant.

When the flow rate learning value for the exhaust gas recirculation device 20 of the previous period N-1 exceeds the preset limit, the controller 30 determines that the flow rate learning value is not effective, and determines the engine fuel amount, A series of flow rate learning for the exhaust gas recirculation device 20 of the current period N is performed by reflecting a reference value, which is derived from the engine speed and the intake valve opening amount, in advance to the flow rate learning value of the local period N. The process will be described in more detail with reference to FIG. 2.

FIG. 2 is a flowchart illustrating a flow rate learning process for the exhaust gas recirculation apparatus of the controller 30 shown in FIG. 1. FIG. 2 illustrates a flow rate learning process for the exhaust gas recirculation apparatus according to an embodiment of the present invention with reference to FIG. 2. do.

First, the controller 30 receives the flow rate learning value of the previous period N-1 for the exhaust gas recirculation valve 20, determines whether the received flow rate learning value exceeds a preset limit value, and determines As a result, when the flow rate learning value exceeds the limit value, it is determined that the flow rate learning value is not valid for the previous period N-1 (steps 101, 103, and 105).

Subsequently, the control unit 30 executes the flow rate learning for the current period N with the reference value stored in advance in step 107, and determines whether the flow rate learning value for the derived current period N exceeds the limit. (Steps 107, 109).

At this time, if the flow rate learning value of the current period (N) exceeds the limit in step 109, the exhaust gas recirculation apparatus 20 is determined to be a failure and then notified to the driver or manufacturer (step 111).

On the other hand, if the flow rate learning value of the current period (N) in step 109 does not exceed the limit value, the controller 30 changes the flow rate learning value for the local period (N) the flow rate of the previous period (N-1) After saving as a learning value, the process proceeds to step 115.

The controller 30 determines whether the flow rate learning end condition of the exhaust gas recirculation apparatus is satisfied in step 115, and ends the program when the flow rate learning end condition of the exhaust gas recirculation apparatus is satisfied.

On the other hand, if the flow rate learning end condition of the exhaust gas recirculation apparatus is not satisfied in step 115, the process proceeds to step 101 and the current period N stored as the flow rate learning value of the previous cycle stored in step 113 is stored. Receive and execute flow rate learning for the next period (N + 1).

However, in step 103, if the flow rate learning value does not exceed the limit, after the flow rate learning is performed for the current period N by reflecting the flow rate learning value of the previous period N-1, step 113 (Step 121).

According to an embodiment of the present invention, when the flow rate learning value for the exhaust gas recirculation device 20 of the previous period N-1 exceeds a preset limit, it is determined that the flow rate learning value is not effective and the engine Since the flow rate learning for the exhaust gas recirculation device 20 of the current period N is performed by reflecting a reference value, which is derived from the fuel amount, the engine speed, and the intake valve opening amount, in advance into the flow rate learning value of the local period N, It is possible to improve the reliability of the flow rate learning value for the exhaust gas recirculation device and to keep the fuel amount constant.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the above-described embodiments are to be understood in all respects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention .

If the flow rate learning value for the exhaust gas recirculation device 20 of the previous cycle N-1 exceeds the preset limit, it is determined that the flow rate learning value is not valid, and the engine fuel amount, engine speed, and intake The flow rate for the exhaust gas recirculation apparatus is executed by performing the flow rate learning for the exhaust gas recirculation apparatus 20 of the current cycle N by reflecting a reference value, which is derived from the valve opening amount, and stored in advance in the flow rate learning value of the local cycle N. It is possible to make great progress in terms of accuracy and reliability of operation, and furthermore, in terms of performance efficiency, for the flow rate learning system and method of the exhaust gas recirculation device which can improve the reliability of the learning value and keep the fuel amount constant. Industrially available because the vehicle is not only commercially available or commercially viable, but also realistically viable. The invention with.

Claims (9)

In the flow rate learning device of the exhaust gas recirculation apparatus for monitoring the exhaust gas of the exhaust gas recirculation apparatus at a predetermined period of a predetermined time unit and intermittently EGR amount based on the oxygen saturation included in the monitored exhaust gas,
A flow rate learning value validity determining step of determining whether the flow rate learning value for the exhaust gas recirculation device of the previous period N-1 exceeds a preset limit value; And
And a flow rate learning execution step of performing flow rate learning for the exhaust gas recirculation apparatus for the current period N with a preset reference value when the flow rate learning value for the previous period determined exceeds the limit. Flow rate learning method of exhaust gas recirculation apparatus of The method according to claim 1, wherein the method,
Determining whether a flow rate learning value of the exhaust gas recirculation device for the current period N exceeds a preset limit value; And
Determining that the flow rate learning value for the current period N exceeds the limit and notifying the driver or manufacturer to the failure of the exhaust gas recirculation device, wherein the flow rate of the exhaust gas recirculation device of the vehicle is further included. Learning method. The flow rate learning value according to claim 2, wherein in the flow rate learning value validity determining step, when the flow rate learning value for the determined previous period does not exceed the limit, the flow rate learning value of the current period N is the flow rate of the previous period N-1. The flow rate learning method of the exhaust gas recirculation apparatus of a vehicle further comprising the step of storing as a learning value. The method of claim 1, wherein the limit value of the flow rate learning value validity determination step is:
If the reflectance rate of the flow rate learning value of the previous cycle (N-1) is 1 during the flow rate learning execution for the current period (N) is set to a value greater than the flow rate learning value reflectance of 1 Flow rate learning method of gas recirculation device. The method of claim 1, wherein the limit value of the flow rate learning value validity determination step is:
If the reflectance of the flow rate learning value of the previous cycle (N-1) is 1 during the flow rate learning execution for the current period (N) is set to a value smaller than the flow rate learning value reflectance of 1 of the vehicle, characterized in that Flow rate learning method of exhaust gas recirculation device. The method according to claim 4 or 5, wherein the reference value,
Flow rate learning of the exhaust gas recirculation apparatus of a vehicle, which is derived based on a predetermined relational expression about fuel amount, engine speed, and intake valve opening amount, and is stored in advance as interpolation table data corresponding to the fuel amount. Way. engine;
An exhaust gas recirculation device for recycling the exhaust gas of the engine; And
When the flow rate learning condition for the exhaust gas recirculation device is satisfied, the controller includes a control unit for monitoring the exhaust gas of the exhaust gas recirculation device at a predetermined period of a predetermined time unit and controlling the EGR amount based on the oxygen saturation included in the monitored exhaust gas. But
The control unit,
It is determined whether the flow rate learning value for the exhaust gas recirculation device of the previous cycle N-1 exceeds the preset limit, and when the flow rate learning value for the previous cycle exceeds the limit, the current period N as the preset reference value. And a flow rate learning for the exhaust gas recirculation apparatus for the vehicle. The method of claim 7, wherein the control unit
It is determined whether the flow rate learning value of the exhaust gas recirculation device for the current period N exceeds a preset limit value,
If the flow rate learning value for the current period (N) exceeds the above limit, the flow rate learning of the exhaust gas recirculation device of the vehicle, characterized in that it is provided to determine the failure to the exhaust gas recirculation device and notify the driver or the manufacturer. system. 9. The apparatus of claim 8,
When the flow rate learning value for the determined previous period does not exceed the limit value, the exhaust of the vehicle, characterized in that it is provided to store the flow rate learning value of the current period (N) as the flow rate learning value of the previous period (N-1) Flow rate learning system of gas recirculation unit.

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