KR101339224B1 - Apparatus for diagnosis cooler exhaust gas recirculation on vehicle and method thereof - Google Patents

Abstract

The present invention relates to an easy cooler diagnosis apparatus for a vehicle, which determines the contamination level of the EGR cooler by adjusting the control duty of the EGR valve, adjusts the boost pressure, and outputs a fault code when a complete contamination of the EGR cooler is detected.

The present invention is a process of learning the EGR valve control duty under constant speed operating conditions, the process of extracting the difference value between the learned control duty and the set reference control duty, it is determined whether the difference value of the extracted control duty is included in the set reference range Determining whether the EGR cooler is contaminated, and adjusting the boost pressure according to whether the EGR cooler is contaminated.

EGR Valve, Control Duty Difference, Boost Pressure, EGR Cooler, Contamination

Description

A device and method for diagnosing a vehicle's easy cooler {APPARATUS FOR DIAGNOSIS COOLER EXHAUST GAS RECIRCULATION ON VEHICLE AND METHOD THEREOF}

The present invention relates to an Exhaust Gas Recirculation (“EGR”) cooler diagnosis apparatus of a vehicle. More particularly, the boost pressure is adjusted by determining the contamination level of the EGR cooler by learning the control duty of the EGR valve. And an EG cooler diagnosis apparatus and method for outputting a fault code when a complete contamination of the EGR cooler is detected.

In general, an EGR valve is applied to a vehicle to reduce the generation of nitrogen oxides (NOx) by re-injecting a part of the exhaust gas discharged from the engine to the combustion chamber in order to lower the combustion temperature of the combustion chamber. EGR coolers for cooling exhaust gases have been applied.

In the case of diesel vehicles, particulate matter (PM) and soot are generated during combustion of the engine, and these substances generate contamination by being adsorbed and deposited on the EGR cooler during the reflow into the engine through the EGR valve. .

Such contamination of the EGR cooler suppresses the exhaust gas flowing back into the engine according to the opening and closing of the EGR valve, thus increasing the NOx generation and causing the problem of worsening the emission.

3 is a view showing the characteristics of the EGR cooler according to the aging in the vehicle, in order to check the contamination problem of the stacked EGR cooler applied to the engine is equipped with an unpolluted initial state of the EGR cooler and then aged for a predetermined time It is a graph that is measured and measured in 30 minutes while (Aging).

As the EGR cooler is contaminated as aging progresses, as shown in (c), the efficiency of the EGR cooler decreases drastically, and as shown in (d), the actual EGR ratio (Ratio) drops rapidly. As a result, as can be seen from (a), it is confirmed that the emission of NOx and smoke is sharply increased.

It has a 20% margin by setting 80% of the NOx emission target in the development of the vehicle.However, when the NOx is rapidly increased due to the contamination of the EGR cooler, and the vehicle is driven over a certain distance, approximately 160,000km, Emmy Sean test conditions cannot be satisfied.

In addition, as the efficiency of the EGR cooler decreases, the temperature of the exhaust gas passing through the EGR cooler increases, and as shown in (e), the temperature of the intake manifold also increases, thereby increasing the air density. As it decreases, the air-fuel ratio decreases, as can be seen in (f), resulting in increased smoke and fuel economy deterioration.

In particular, in order to increase the cooling efficiency, the stacked EGR cooler has a plurality of pin-shaped small flow paths formed in the passage of the EGR gas, so that the soot component of the exhaust gas generated by the combustion of the engine is the fin of the EGR cooler. The small buildup in the flow path leads to a sharp deterioration in the efficiency of the EGR cooler, and the supply field blocks the pin flow path.

The present invention has been invented to solve the above problems, to learn the control duty of the EGR valve to determine the degree of contamination of the EGR cooler, and to stabilize the emission by adjusting the amount of EGR through the boost pressure adjustment according to the degree of contamination The purpose is.

In addition, when the complete contamination of the EGR cooler is detected, the purpose is to output a fault code through the display means to enable a quick cleaning and restoration.

According to an aspect of the present invention, there is provided an apparatus for diagnosing a cooler of a vehicle, the air cooler comprising: an air mass sensor; A turbocharger for charging intake air; An EGR cooler for cooling the exhaust gas flowing into the engine; EGR valve to adjust the amount of exhaust gas flowing into the engine,

A controller which analyzes the difference between the learning value of the EGR control duty and the reference value to determine whether the EGR cooler is contaminated, and adjusts the EGR amount by adjusting the boost pressure according to the degree of contamination;

And a display unit for indicating contamination information of the EGR cooler under the control of the controller.

In addition, the method of diagnosing the easy cooler of a vehicle according to another aspect of the present invention,

Learning the EGR valve control duty under constant speed operating conditions;

Extracting a difference value between the learned control duty and the set reference control duty;

Determining whether the EGR cooler is contaminated by determining whether the difference value of the extracted control duty is included in a set reference range;

And adjusting the boost pressure according to whether the EGR cooler is contaminated.

By the above-described configuration, the present invention provides a highly efficient EGR cooler to the vehicle to more effectively satisfy the enhanced exhaust regulation, and prevents the increase of the emission caused by the contamination of the EGR cooler even after a prescribed distance. The effect of maintaining the option is expected.

In addition, when serious contamination (almost clogging) of the EGR cooler is detected, the fault code is displayed as a warning light on the dashboard of the driver's seat to enable rapid cleaning and restoration, thereby providing stabilization of the emission.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

Since the present invention can be implemented in various different forms, the present invention is not limited to the exemplary embodiments described herein, and parts not related to the description are omitted in the drawings in order to clearly describe the present invention.

1 is a view schematically illustrating an apparatus for diagnosing an EG cooler of a vehicle according to an exemplary embodiment of the present invention.

The present invention is a power source of the engine 100 and filter 101, air volume sensor 102, turbocharger 103, catalyst 104, actuator 105, intercooler 106, boost pressure sensor 107, EGR It includes a cooler 108, an EGR valve 109, a control unit 200, and a display unit 210.

The filter 101 is installed in the intake duct to remove impurities and moisture contained in the air sucked from the atmosphere.

The air volume sensor 102 detects the amount of intake air supplied through the filter 101 and provides information about the intake air to the controller 200.

The turbocharger 103 is composed of a turbine and a compressor, and is operated by the thermal energy of the exhaust gas discharged from the engine 100 to compress and intake air that is sucked.

Catalyst 104 stabilizes the emission by purifying NOx, HC, particulate matter (PM), soot (Soot) and the like contained in the exhaust gas.

The actuator 105 is operated according to the control signal (VGT duty) of the controller 200 to adjust the vane angle of the turbocharger 103 to adjust the amount of air charged, that is, the boost pressure.

The intercooler 106 cools the air charged by the turbocharger 103 and supplies it to the engine 100 with a stable distribution of oxygen.

The boost pressure sensor 107 detects the pressure of the air charged to the engine 100 and provides the information about the pressure to the ECU 200.

The EGR cooler 108 is, for example, a stacked cooler that cools the exhaust gas for reflow into the engine.

The EGR valve 109 is operated according to the control signal EGR_Duty of the controller 200 to adjust the amount of exhaust gas recycled to lower the combustion temperature of the engine 100.

The controller 200 learns the control duty of the EGR valve 109 under constant speed operation conditions in which the engine speed is maintained at a set speed, for example, 1500 RPM, and the fuel amount is set at a predetermined amount, for example, 20 mg / st. When the difference ΔEGR between the learning value EGR_new and the set reference value ERG_org is detected and included in the range of the set reference value, the boost pressure is increased by adjusting the vane angle of the turbine through the actuator 105.

Therefore, the exhaust gas flowing into the engine 100 through the EGR valve 109 is increased due to the increase in intake negative pressure according to the increase in the boost pressure to stabilize the emission.

In addition, the controller 200 sets the duty of the EGR valve 109 to 100% in a state in which the difference ΔEGR between the learning value EGR_new and the set reference value EGR_org of the EGR duty is not included in the range of the set reference value. If it is in the output state, it is determined that the serious contamination of the EGR cooler 108, and the fault code is output through the display unit 210.

The display unit 210 is provided in a cluster, and instructs the driver of contamination information of the EGR cooler 108 under the control of the controller 200 so that quick repair recovery can be performed.

Referring to the operation of the present invention that includes the above-described function in detail as follows.

In a state in which the vehicle is being driven, the controller 200 collects and analyzes general driving information including an engine speed, a fuel amount, an intake air amount, a boost pressure (S101), and determines whether the vehicle maintains a constant speed driving (S102).

In S102, for example, when the engine speed is maintained at 1500 RPM and the fuel flow rate is determined to be constant speed driving at 20 mg / st, the EGR valve 109 duty learning condition for determining contamination of the EGR cooler 108 is satisfied. To judge.

When the EGR valve 109 duty learning condition is satisfied in the constant speed as described above, it is determined whether the reference control duty EGR_org of the EGR valve 109 is a reset condition (S103).

If the reference control duty (EGR_org) of the EGR valve 109 is a reset condition in S103, the control duty of the EGR valve 109 is learned and stored as a reference control duty (EGR_org) value under the constant speed driving condition, and then the process of S101 is performed. Is returned.

However, if the reference control duty EGR_org of the EGR valve 109 is not a reset condition in step S103, the control duty of the EGR valve 109 is learned under the current condition in which the vehicle maintains constant speed and the learning value EGR_new is obtained. Save (S105).

Thereafter, the reference control duty EGR_org of the EGR valve 109 is compared with the learning value EGR_new to calculate a difference value DELTA EGR of the EGR control duty (S106).

Then, it is determined whether the calculated difference value? EGR of the EGR control duty is included in the range of the set first reference value and second reference value (S107).

The range of the first reference value and the second reference value is set to a value of 20 to 25%.

When the difference value ΔEGR of the EGR control duty is included in the range of the set first reference value and second reference value in the determination of S107, it is determined that the EGR cooler 108 is contaminated by a certain amount and does not have a normal cooling efficiency, and the engine rotates. By adjusting the vane angle of the turbine through the actuator 105 by applying a correction map set to the number and the fuel amount, the boost pressure PCR_P of the air sucked into the engine 100 is increased (S109).

Accordingly, the intake negative pressure increases as the boost pressure PCR_P sucked into the engine 100 increases. As a result, the inlet / outlet pressure difference of the EGR valve 109 increases, thereby increasing the actual EGR rate to increase the EGR cooler 108. Makes the emission stable by compensating for the loss of efficiency degradation due to the constant amount of contamination.

In addition, as the boost pressure PCR_P sucked into the engine 100 increases, the air density sucked increases, thereby keeping the air-fuel ratio stable to reduce smoke and improve fuel efficiency.

If the difference value ΔEGR of the EGR control duty is not included in the range of the set first reference value and the second reference value in the determination of step S107, it is determined whether the range of the set third reference value and the fourth reference value is included (S108).

The range of the third reference value and the fourth reference value is set to a value of 40 to 45%.

If the difference value ΔEGR of the EGR control duty is not included in the range of the third reference value and the fourth reference value in the determination of S108, the EGR cooler 108 determines that the normal state is not contaminated and returns to the process of S101. .

However, if the difference value ΔEGR of the EGR control duty falls within the range of the third reference value and the fourth reference value, as described above, it is determined that the EGR cooler 108 is contaminated to a considerable extent and does not have normal cooling efficiency. In response to the correction map set to the engine speed and the fuel amount, the vane angle of the turbine is adjusted through the actuator 105 to increase the boost pressure PCR_P of the air sucked into the engine 100 (S109).

Accordingly, the intake negative pressure increases as the boost pressure PCR_P sucked into the engine 100 increases. As a result, the inlet / outlet pressure difference of the EGR valve 109 increases, thereby increasing the actual EGR rate to increase the EGR cooler 108. Makes the emission stable by compensating for the loss of efficiency degradation due to the constant amount of contamination.

In addition, as the boost pressure PCR_P sucked into the engine 100 increases, the air density sucked increases, thereby keeping the air-fuel ratio stable to reduce smoke and improve fuel efficiency.

As the vehicle continues to run, the EGR cooler 108 becomes more contaminated, and the difference value (ΔEGR) of the EGR control duty continues to increase, so that the boost pressure is increased once more in the second reference value and the fourth reference value. .

However, when the difference value ΔEGR of the EGR control duty exceeds the range of the third reference value and the fourth reference value, it is determined whether the control duty ERG_new of the currently controlled EGR valve 109 is a 100% value, and the amount of air It is determined whether the difference between the set reference amount (for example 20mg / st) or more (S110).

If the control duty EGR_new of the currently controlled EGR valve 109 is 100% and the difference in air amount is less than or equal to the set reference amount, the process returns to step S101, and the control of the currently controlled EGR valve 109 is performed. If the control duty ERG_new is 100% and the difference in air amount is equal to or greater than the set reference amount, it means that the reference air amount cannot be followed even though the EGR valve 109 is fully opened to match the reference air amount.

Therefore, the control unit 200 determines that the EGR cooler 108 is a failure state in which the contamination of the EGR cooler 108 is very serious and does not function (S111).

When the failure of the EGR cooler 108 is determined as described above, the fault code is output through the display unit 210 provided in the cluster to warn the driver of the contamination of the EGR cooler 108 (S112).

Thereafter, it is determined whether the failure action of the EGR cooler 108 is completed (S113), and when the failure action is completed, the reference control duty ERG_org of the EGR valve 109 is reset, and then it is learned and stored in the constant speed driving (S114). Judge whether you did.

For example, the above operation will be described as follows.

EGR cooler is set to meet this target air volume if the specific engine operating condition is selected in advance, i.e., the engine speed is 1500 RPM, and the target air volume set as the map value is 360 mg / st in the constant speed operation condition where the fuel amount is injected at 20 mg / st. In a state where 108 is not contaminated, it is assumed that the control duty of the EGR valve 109 is 20%.

As the vehicle runs, the EGR cooler 108 becomes increasingly polluted, and thus the efficiency of cooling the exhaust gas is rapidly deteriorated, so that the control duty of the EGR valve 109 is controlled to 40% instead of 20% to meet the same target air volume. do.

Therefore, using this principle, the control duty ERG_org of the first EGR valve 109 is stored, the control duty ERG_new is periodically learned, and the difference value Δ EGR of the EGR control duty is analyzed to determine the EGR cooler ( 108) determine the degree of contamination.

In addition, by adjusting the vane angle of the turbine according to the degree of contamination, the boost pressure of the air sucked into the engine is increased to allow the EGR amount to flow into the previous amount of contamination, thereby maintaining the emission stable.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It is included in the scope of right.

1 is a view schematically showing an EG cooler diagnostic apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an RG cooler diagnosis procedure according to an exemplary embodiment of the present invention.

3 is a view showing the characteristics of the EZR cooler according to the aging in the vehicle.

<Explanation of symbols for the main parts of the drawings>

100: engine 101: filter

102: air volume sensor 103: turbocharger

104: catalyst 105: actuator

106: intercooler 107: boost pressure sensor

108: EGR cooler 109: EGR valve

200: control unit 210: display unit

Claims (7)

Air mass sensor; A turbocharger for charging intake air; An EGR cooler for cooling the exhaust gas flowing into the engine; EGR valve to adjust the amount of exhaust gas recycled to the engine, A controller which analyzes the difference between the learning value of the EGR control duty and the reference value to determine whether the EGR cooler is contaminated, and adjusts the EGR amount by adjusting the boost pressure according to the degree of contamination; A display unit for indicating contamination information of the EGR cooler under the control of the controller; Easy cooler diagnostic device of a vehicle further comprising a. The method of claim 1, And the controller is configured to determine whether the EGR cooler is contaminated in a constant speed condition in which the engine speed maintains a constant speed and the fuel amount maintains a constant amount. The method of claim 1, When the difference between the learning value and the reference value of the EGR control duty is included in the range of the first reference value and the second reference value, the controller adjusts the boost pressure to the primary by applying a correction map, and includes it in the range of the third reference value and the fourth reference value. EZ Cooler Diagnosis Device of Vehicle to increase intake negative pressure by adjusting boost pressure by applying correction map. The method of claim 1, The control unit outputs a fault code indicating contamination of the EGR cooler when the difference between the learning value of the EGR control duty and the reference value exceeds the set reference value, the EGR control duty is output as 100%, and the difference in air volume is greater than the reference amount. Easy cooler diagnostic device of a vehicle. Learning the EGR valve control duty under constant speed operating conditions; Extracting a difference value between the learned control duty and the set reference control duty; Determining whether the EGR cooler is contaminated by determining whether the difference value of the extracted control duty is included in a set reference range; Adjusting an EGR amount by adjusting a boost pressure according to whether the EGR cooler is contaminated; Easy cooler diagnostic method of a vehicle comprising a. The method of claim 5, The boost pressure adjustment according to whether the EGR cooler is contaminated is carried out step by step according to the difference value of the control duty. The method of claim 5, If the difference value of the EGR control duty exceeds the set range, the control duty is output at 100% and the difference in the air volume is more than the reference amount, the IR cooler diagnostic method of the vehicle outputting the fault code of the EGR cooler.

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