KR100952788B1

KR100952788B1 - Method for Handiling Bad Contact of Common Rail Pressure Sensor

Info

Publication number: KR100952788B1
Application number: KR1020080028430A
Authority: KR
Inventors: 김세용
Original assignee: 기아자동차주식회사; 현대자동차주식회사
Priority date: 2008-03-27
Filing date: 2008-03-27
Publication date: 2010-04-14
Also published as: KR20090103074A

Abstract

The present invention relates to a method for coping with poor contact of a common rail pressure sensor, comprising: a first step of determining whether or not an error occurs in a common rail pressure sensor when the engine is started; And a second step of matching the measured rail pressure value to the ECU target rail pressure when there is an error in the common rail pressure sensor. According to the present invention, by matching the pressure value of the common rail pressure sensor to the set target value when the contact of the common rail pressure sensor is poor, it is possible to prevent starting failure due to a poor contact of the common rail pressure sensor, thereby reducing consumer complaints. It can solve the problem, and further improve the customer satisfaction with the vehicle.

Common Rail Pressure Sensor, Cooling Water Temperature, Rail Pressure Value, Poor Contact, Poor Start

Description

Method for handling bad contact of common rail pressure sensor {Method for Handiling Bad Contact of Common Rail Pressure Sensor}

The present invention relates to a common rail pressure sensor, and more particularly to a method for coping with poor contact of the common rail pressure sensor.

1 is a configuration diagram of a fuel control system of a common common rail engine.

Each cylinder of the common rail engine described above is provided with an injector 1. The injector 1 is provided with a high pressure pipe 2 and a rail pressure (several 10 to 100 Mpa) stored in the common rail 3. High pressure fuel is normally supplied. The fuel feeding in the common rail 3 is mainly performed by a feed pump (high pressure pump 4). That is, the fuel at the normal pressure of the fuel tank 5 is drawn into the feed pump 7 through the fuel filter 6, and the fuel is sent to the feed pump 4 through the feed pipe 8 by this. Here the fuel is pressurized to high pressure and sent to the common rail 3 through the high pressure pipe 9.

Therefore, the control device 10 in charge of fuel injection control sends a predetermined driving pulse to the solenoid valve 11 of the injector 1 according to the operating state of the engine (engine rotation speed, engine load, etc.), and the injector 1. Open / close control). When the solenoid valve 11 is turned on, fuel injection is performed. When the solenoid valve 11 is turned off, fuel injection is stopped. When the fuel injection stops, the leak fuel in the injector 1 is returned to the fuel tank 5 through the leak pipe 12.

At this time, the controller 10 reads the engine speed from the output of the engine speed sensor 15, reads the throttle valve opening degree from the output of the throttle valve opening sensor 16, and then outputs the atmospheric pressure sensor 17. The atmospheric temperature is read from the engine, the water temperature of the engine is read from the output of the water temperature sensor 18, and the rail pressure is read from the output of the common rail pressure sensor 13. In addition, various types of information are read from various sensors not shown, and the optimum fuel injection control is executed based on the information.

However, in the case of the conventional common rail engine, an engine starting failure may occur due to a poor contact that may occur in the common rail pressure sensor 13. That is, a poor contact that occurs while driving the vehicle remains even after the engine stops due to the driver's operation, which may cause the actual rail pressure to be incorrectly transmitted to the ECU (Electronic Control Unit). This is not done correctly and the engine will not start.

The present invention has been made to solve the above problems, the object of the present invention is to provide a method for coping with poor contact of the common rail pressure sensor for preventing starting failure due to poor contact of the common rail pressure sensor after long-term parking. have.

The present invention for achieving the above object, the first step of determining whether or not the common rail pressure sensor at the time of engine start; And a second step of matching the measured rail pressure value to the ECU target rail pressure when the common rail pressure sensor has an abnormality.

Preferably, the first step is to store the cooling water temperature (T1) in the ECU (Electronic Control Unit) after the engine is stopped, the temperature difference between the current cooling water temperature (T2) and the cooling water temperature (T1) stored in the ECU at engine start-up The reference value is compared to determine whether the measured rail pressure value is within a normal range when the temperature difference is greater than the reference value.

As described above, according to the present invention, when the contact of the common rail pressure sensor is poor, by matching the pressure value of the common rail pressure sensor to the set target value, it is possible to prevent starting failure due to poor contact of the common rail pressure sensor. As a result, it is possible to resolve the dissatisfaction of the consumer and further improve the customer satisfaction with the vehicle.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying 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.

Example

2 is a graph illustrating a method of determining whether or not an error occurs in the common rail pressure sensor upon restarting the engine after the engine is stopped.

Referring to FIG. 2, if the temperature difference between the current cooling water temperature T2 and the cooling water temperature T1 stored in the ECU (Electronic Control Unit) after the driver turns off the engine is greater than a predetermined value, for example, 15 ° C. When the rail pressure becomes 0 afterwards, it is determined whether the rail pressure is out of the normal range (for example, the reference value ± 15 Mpa) to determine whether the common rail pressure sensor is abnormal.

3 is a flowchart illustrating a method of responding to poor contact of a common rail pressure sensor according to an exemplary embodiment of the present invention.

Referring to FIG. 3, after the engine stops, the coolant temperature T1 is stored in the ECU (S310).

Subsequently, it is determined whether the temperature difference between the current cooling water temperature T2 and the cooling water temperature T1 stored in the ECU is greater than a predetermined value in order to determine a time point at which the rail pressure value becomes zero at engine startup (S320). In general, when the cooling water temperature drops 15 ° C after engine shutdown, the rail pressure becomes zero.

When the temperature difference is greater than the predetermined value in step S320, it is determined whether the measured rail pressure value is within a normal range (S330). Here, when the measured rail pressure value is within the normal range, the engine starts normally (S340).

When the rail pressure value measured in step S330 is out of the normal range, the measured rail pressure value matches the ECU target rail pressure (S324).

Finally, the engine warning light is turned on to inform the common rail pressure sensor of abnormality and the fuel level is limited so that the driver can identify the problem of the vehicle and go to the repair shop.

When the temperature difference is smaller than the predetermined value in step S320, it is determined whether or not there is an abnormality in the common rail pressure sensor by comparing the measured change amount of the rail pressure value and the value of the created map MAP (S322). Here, the map means a reference table showing the rail pressure change amount according to the cooling water temperature change amount.

If the common rail pressure sensor is abnormal in step S322, the rail pressure value measured as in step S324 is matched with the ECU target rail pressure, and the engine is normally started when the common rail pressure sensor operates normally (S340).

Figure 4 is a graph showing the verification result of the contact failure response logic of the common rail pressure sensor according to the present invention.

Referring to FIG. 4, (a) is a graph in which there is no contact failure-corresponding logic. When the driver starts up (XKEY = 0 → 1), starting of the common rail pressure sensor does not start (Ne = 0).

(b) is a graph with contact failure response logic. When the driver starts (XKEY = 0 → 1), the engine starts and all functions operate normally even if the common rail pressure sensor malfunctions. 1000).

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

1 is a configuration diagram of a fuel control system of a common common rail engine;

Figure 2 is a graph for explaining a method for determining whether or not there is an error in the common rail pressure sensor when restarting the engine in the present invention,

3 is a flow chart showing a method for responding to a poor contact of the common rail pressure sensor according to an embodiment of the present invention,

Claims

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A first step of determining whether or not there is an error in the common rail pressure sensor when the engine is started; And

A second step of matching the measured rail pressure value to the ECU target rail pressure when the common rail pressure sensor is abnormal; Including,

In the first step, after the engine stops, the coolant temperature T1 is stored in the ECU (Electronic Control Unit), and when the engine starts, the temperature difference between the current coolant temperature T2 and the coolant temperature T1 stored in the ECU is compared with a reference value. When the temperature difference is greater than the reference value, it is determined whether the measured rail pressure value is within the normal range.

The method of claim 2,

When the temperature difference is smaller than the reference value, the common rail pressure, characterized in that the common rail pressure sensor characterized in that it is determined whether or not the common rail pressure sensor by comparing the measured change amount of the rail pressure value and the value of the generated map (MAP) How to handle poor contact of sensor.

The method of claim 3,

Wherein the map is a reference table showing the rail pressure change according to the change amount of the coolant temperature, the contact failure response method of the common rail pressure sensor.

The method according to any one of claims 2 to 4, wherein after the second step,

A third step of turning on an engine warning light and limiting the fuel amount in order to notify the abnormality of the common rail pressure sensor when the common rail pressure sensor is abnormal;

Contact failure response method of the common rail pressure sensor further comprises.