KR101554974B1 - Diagnosis method for high pressure fuel pump - Google Patents

Diagnosis method for high pressure fuel pump Download PDF

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Publication number
KR101554974B1
KR101554974B1 KR1020130149050A KR20130149050A KR101554974B1 KR 101554974 B1 KR101554974 B1 KR 101554974B1 KR 1020130149050 A KR1020130149050 A KR 1020130149050A KR 20130149050 A KR20130149050 A KR 20130149050A KR 101554974 B1 KR101554974 B1 KR 101554974B1
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South Korea
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pressure
value
fuel pump
time
fuel
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KR1020130149050A
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Korean (ko)
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KR20150064390A (en
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김대훈
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주식회사 현대케피코
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

A method for diagnosing the abnormality of a high-pressure fuel pump is disclosed. A method for diagnosing a high-pressure fuel pump according to an aspect of the present invention includes the steps of: detecting a first point-of-view pressure value of a fuel rail through a pressure sensor; Comparing a first closing timing of the solenoid control valve determined to maintain the first time pressure value with a modeled database and outputting a first verification result according to the deviation information; Detecting a second time pressure value at the fuel rail after the solenoid control valve is closed to compress the fuel at the first closing timing; And outputting a second verification result according to the deviation information between the first time pressure value and the second time pressure value.

Description

[0001] The present invention relates to a high-pressure fuel pump,

The present invention relates to a high-pressure pump, and more particularly, to a method for diagnosing an abnormality of a high-pressure fuel pump.

2. Description of the Related Art Generally, a high-pressure fuel pump installed in an automobile is a device for supplying fuel to an engine at a high pressure by the driving force of the engine. Generally, the high-pressure fuel pump is driven by the rotational force of the engine.

The operation of a conventional high-pressure fuel pump will now be described with reference to the accompanying drawings. 1 is a view for explaining the operation of a conventional high-pressure fuel pump.

The camshaft 40 connected to the crankshaft 20 and the belt 30 (or chain) rotates as the crankshaft 20 of the engine 10 rotates. At this time, the piston 120 of the high-pressure fuel pump 100 rises by the cam 50 formed on the camshaft 40, and the piston 120 is lowered by the return spring 170 to be injected into the chamber 180 The high-pressure fuel is discharged to the discharge port 160, and the high-pressure fuel is supplied to the engine 10. At this time, the injection port 140 of the high-pressure fuel pump 100 is provided with a solenoid valve 60 for controlling injection of fuel.

On the other hand, the high-pressure fuel discharged through the discharge port 160 is subjected to a fuel pressure control process in a high-pressure regulator (not shown), then supplied to the fuel rail and injected into the engine via the fuel injection nozzle. At this time, the fuel pressure control was performed through a simple feedback control process without hardware modification to the high pressure fuel pump. However, if a hardware modification is not accompanied, a large frictional loss is generated in the driving force transmitting means such as the engine 10, the crankshaft 20, the belt 30 and the camshaft 40 even when the low fuel pressure is generated. I can not help it. This leads directly to the torque loss of the vehicle and can adversely affect the fuel economy, performance and environmental pollution of the vehicle.

 In particular, since the high-pressure pump is driven by a pump lobe integrally formed with the camshaft, when the TDC of the high-pressure pump is varied due to machining variations of the pump lobe, the closing timing of the control valve for discharging the same flow rate is changed The value also changes.

If the camshaft with the pump lobe has abrasion or misalignment of the timing belt or chain, the TDC of the high-pressure pump is abnormally opened, so that the closing timing of the control valve is also changed and the learning value is also changed.

The present invention provides a method for diagnosing an abnormality of a high-pressure fuel pump by monitoring a control value fed back from an engine control device in order to maintain a target fuel pressure value The purpose.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

According to another aspect of the present invention, there is provided a diagnostic method for a high-pressure fuel pump performed by an engine control means, the method comprising the steps of: Detecting a value; Comparing a first closing timing of the solenoid control valve determined to maintain the first time pressure value with a modeled database and outputting a first verification result according to the deviation information; Detecting a second time pressure value at the fuel rail after the solenoid control valve is closed to compress the fuel at the first closing timing; And outputting a second verification result according to the deviation information between the first time pressure value and the second time pressure value.

In a preferred embodiment, the step of outputting the first verification result may include determining that the deviation between the first closing timing and the value stored in the modeled database is within a preset tolerance range, It is determined that there is an error.

In a preferred embodiment, the outputting of the second verification result may be performed only when it is determined that the high-pressure fuel pump is normal as a result of the first verification.

On the other hand, in the step of outputting the second verification result, it is determined that the deviation is between a first time pressure value and a second time pressure value within a predetermined error range. If the deviation is outside the error range, And a step of judging that there is a difference.

According to another aspect of the present invention, there is provided a method for diagnosing a high-pressure fuel pump, wherein when the deviation between the first point of view pressure value and the second point of view pressure value is within a predetermined error range, And updating the modeled database by learning the timing.

As described above, according to the present invention, only the control value fed back from the engine control unit can be monitored, so that the abnormality of the high-pressure fuel pump can be diagnosed easily.

1 is a view for explaining the operation of a conventional high-pressure fuel pump;
2 is a schematic diagram of a fuel system of a GDI engine according to an embodiment of the present invention.
3 illustrates a structure of a high-pressure pump in a fuel system of a GDI engine according to an embodiment of the present invention.
4 is a flowchart showing a diagnostic method of a high-pressure fuel pump according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same or similar components throughout the drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The present invention proposes a method for diagnosing the abnormality by monitoring the control value of a high-pressure fuel pump in a fuel supply system of a gasoline direct injection engine. In order to explain this, the operation principle of the fuel system of the GDI engine and the structure of the high-pressure pump in the fuel system of the GDI engine will be schematically described with reference to FIGS. 2 and 3.

GDI  Engine fuel system

The fuel system of the GDI engine is equipped with a low pressure pump 210 which is operated as a motor to supply fuel to the fuel rail 400 and a high pressure pump 300 operated by the camshaft, And is mounted on the cover 220.

An injector 410 for injecting the calculated amount of fuel into each of the combustion chambers is mounted and at the end of the fuel rail 400 is detected the pressure inside the fuel rail 400, A pressure sensor 420 is mounted.

Accordingly, the fuel supplied from the fuel tank 200 to the engine by the operation of the low-pressure pump 210 is pressurized to a predetermined pressure set by the high-pressure pump 300 operated by the camshaft, to about 120 bar, .

At this time, the pressure sensor 420 mounted on the end of the fuel rail 400 detects the pressure formed on the fuel rail 400 and applies the detected pressure to the engine control means (not shown).

Therefore, the engine control means performs the fuel pressure feedback control so as to maintain the optimum pressure for each operating condition.

Structure of high pressure pump

The high pressure pump 300 includes a plunger 301, a pump lobe 600 integrally formed with the cam shaft, a control valve 320, and a solenoid 330.

The high pressure pump 300 is a positive displacement pump in which the plunger 310 presses the fuel while reciprocating vertically in accordance with the operation of the pump lobe 600. The maximum discharge flow rate per stroke corresponds to the volume trajectory created by the plunger 310 do.

Since the fuel is delivered only when the control valve 320 is closed, the engine control means (not shown) controls the discharge amount of the fuel by adjusting the closing time of the control valve 320 through the solenoid 330.

For example, when the target fuel pressure is determined in the specific operating condition determined by the engine speed and the load, the engine control means (not shown) adjusts the closing time of the control valve 320 through the solenoid 330, 40, feedback control is performed so that the target fuel pressure is formed.

In order to maintain the fuel pressure formed on the fuel rail 400 at the target fuel pressure determined according to the operating conditions, the fuel is continuously supplied through the operation of the high-pressure pump 300 by the fuel amount injected to the injector 410.

If the supply amount through the high-pressure pump 300 exceeds the injection amount by the injector 410, the pressure inside the fuel rail 400 is raised, and in the opposite case, the pressure inside the fuel rail 400 is reduced.

Therefore, the engine control means adjusts the closing timing of the control valve 320 mounted on the high-pressure pump 300 according to the pressure of the fuel rail 400 detected through the pressure sensor 420, Maintain fuel pressure at all times.

Diagnosis method of high pressure pump

On the other hand, according to the embodiment of the present invention, the control value by which the engine control means adjusts the closing time of the control valve 320 through the solenoid 330 is monitored, and based on this control value, Is diagnosed.

Hereinafter, a diagnostic method of the high-pressure fuel pump according to the present invention will be described in detail with reference to FIG. 4 is a flowchart showing a diagnostic method of a high-pressure fuel pump according to an embodiment of the present invention.

First, it is checked whether or not the condition for diagnosing the abnormality of the high-pressure fuel pump is satisfied. If the condition is met, the diagnostic process is started (S5). Here, the diagnosis condition means a state in which the control values for controlling the high-pressure fuel pump are not largely varied, and the constant values are continuously maintained. That is, it means that the vehicle has entered a stable state. For example, the RPM may maintain a constant value over a predetermined time, the injected flow rate may be constant, or the vehicle speed may be zero.

The pressure sensor 420 mounted on the end of the fuel rail 400 detects the first pressure value formed on the fuel rail 400 at the first time point and outputs the first pressure value to the engine control means (S10).

Thereafter, the engine control means calculates a control value required for the fuel pump 300 to maintain the first pressure value.

As a representative example, when the target fuel pressure (here, the first pressure value) is determined in the engine operation speed and the specific operating condition determined by the load, the engine control means determines the closing time of the control valve 320 through the solenoid 330 The fuel rail 400 can be subjected to feedback control so that the target fuel pressure is formed.

Therefore, the engine control means determines the first closing timing of the solenoid control valve 320 for maintaining the first pressure value in step S20.

The first closing timing determined in step S20 is utilized as a basic data for determining whether or not the fuel pump 300 is abnormal. To this end, information regarding the timing of closing the solenoid control valve for forming the target fuel pressure under certain operating conditions determined by the engine speed and the load may be modeled and stored in a database.

In step S30, the engine control unit compares the first closing timing of the solenoid control valve, which is determined to maintain the first time pressure value, with the modeled database, and outputs the first verification result according to the deviation information.

As a result of the verification, if the deviation between the first closing timing and the value stored in the modeled database is within a predetermined error range, it is determined to be normal. If the difference is outside the error range, it is determined to be an error (S45).

On the other hand, when it is determined in step S30 that the deviation is within a predetermined error range and is determined to be normal, the engine control means detects the fuel pressure value at the second time point according to the first closing timing, The process of revalidating the primary verification results is performed.

Specifically, if it is determined that the first verification result is an error, revalidation is not required to prevent an accident that may occur due to the failure of the fuel pump.

However, even if it is judged as a result of the first verification, there is an error in the verification process itself. Therefore, a re-verification process is required to derive an accurate diagnosis result.

To this end, the engine control means controls the fuel pressure in the fuel rail 400 at the second time point after the solenoid control valve 320 is closed and the fuel is compressed according to the first closing timing (Step S40).

Thereafter, the engine control means compares the first point-of-view pressure value and the second point-of-view pressure value and outputs a second verification result according to the deviation information (S50).

As a result of the second verification, it is determined that the deviation between the first pressure value and the second pressure value is within a preset error range. If the difference is outside the error range, it is determined that the error is normal.

Through the re-verification process such as S50, the engine control means finally outputs the diagnostic result of the abnormality of the fuel pump, and as a result, when the final judgment is made (that is, (I.e., when the deviation of the second viewpoint pressure value is within a predetermined error range), the first closing timing is learned and the modeled database is updated (S60).

Here, the updated database can be used again in the first verification of step S30.

On the other hand, the information about the closing timing of the solenoid control valve for forming the target fuel pressure in a specific operating condition is continuously learned. The learned information about the closing timing of the control valve can be used to diagnose the abnormality of the high- have.

For example, the engine control means stores information on the initial control value relating to the closing timing of the solenoid control valve for forming the target fuel pressure in a specific operating condition determined by the specific engine speed and the load, and the control values learned and updated . There may be a difference between the initial control value and the learned control value for forming the same target fuel pressure under the same conditions as the learning of the control value continues. This can be attributed to the mechanical aging phenomenon of the high-pressure fuel pump.

Accordingly, the engine control means compares the initial control value with the current control value, which is the learned result, and diagnoses the abnormality of the high-pressure fuel pump in a differential manner according to the degree of the deviation.

Specifically, the engine control means compares the current control value (modeling value), which is the learned result, with the initial control value, and confirms whether or not the deviation deviates from the predetermined error limit. If the deviation deviates from the predetermined error limit, it is diagnosed that there is an abnormality in the high-pressure fuel pump.

On the other hand, in diagnosing the abnormality of the high-pressure fuel pump using the modeled learning control value, the engine control means can further output the differential diagnosis result by utilizing the time concept.

For example, assume that the first learning control value to be compared is a value obtained at a time point t1 after the learning control is started, and the second learning control value is a value obtained at the time point t2 . Here, the time of t1 means a time when a short time has elapsed from the initial time, and the time of t2 means a time when a long time has elapsed from the initial time.

If the deviation between the first learning control value and the initial control value obtained at the time t1 deviates from the error limit, it means that a large change has occurred in the short time. For example, this means that a large leakage of the high- It can mean something.

On the other hand, if the deviation between the second learning control value and the initial control value obtained at time t2 deviates from the error limit, it may mean that the fuel leaks gradually over a long time.

In this way, the engine control means can make a differential diagnosis of the presence or absence of abnormality possible by further considering the factors of the elapsed time from the initial point of time when the learning control is started by using the modeled learning control value.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the scope of the claims and their equivalents shall be construed as being included within the scope of the present invention.

Claims (7)

A method for diagnosing a high-pressure fuel pump performed by an engine control means,
Detecting a first point of view pressure value of the fuel rail through a pressure sensor;
Comparing a first closing timing of the solenoid control valve determined to maintain the first time pressure value with a modeled database and outputting a first verification result according to the deviation information;
Detecting a second time pressure value at the fuel rail after the solenoid control valve is closed to compress the fuel at the first closing timing;
Outputting a second verification result according to deviation information between the first time pressure value and the second time pressure value; And
When the deviation between the first pressure value and the second pressure value is within a predetermined error range as a result of the second verification, updating the modeled database by learning the first closing timing
Pressure fuel pump.
The method according to claim 1, wherein the outputting of the first verification result comprises:
Determining that the deviation between the first closing timing and the value stored in the modeled database is within a predetermined error range, and determining that the error is outside the error range;
A method for diagnosing a high pressure fuel pump.
The method of claim 1, wherein the outputting of the second verification result comprises:
And is performed only when it is determined that the high-pressure fuel pump is normal as a result of the first verification
A method for diagnosing a high pressure fuel pump.
The method of claim 1, wherein the outputting of the second verification result comprises:
Determining that the deviation between the first pressure value and the second pressure value is within a predetermined error range, determining that the pressure difference is normal, and if the difference is outside the error range,
A method for diagnosing a high pressure fuel pump.
delete The method according to claim 1,
The learning value for the first closing timing at the present time and the control value for the first closing timing set at the initial timing are compared with each other to form the same target fuel pressure under specific operating conditions determined by the engine speed and the load ; And
If the difference between the learning value of the current time point and the control value set at the initial time point is within a predetermined error range as a result of the comparison, it is determined that the error is out of the error range,
Pressure fuel pump.
7. The method according to claim 6, wherein the outputting of the diagnosis result comprises:
The case where the learning value at the current time is the first learning control value learned after the elapse of the time t1 with respect to the initial bookstore and the case where the learning value is the second learning control value learned after the elapse of the time t2 with respect to the initial time point , And outputting a differential diagnosis result
A method for diagnosing a high pressure fuel pump.
KR1020130149050A 2013-12-03 2013-12-03 Diagnosis method for high pressure fuel pump KR101554974B1 (en)

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KR101554974B1 true KR101554974B1 (en) 2015-09-22

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