JP5182012B2 - Method for determining clogging life of fuel filter of internal combustion engine and internal combustion engine using the same - Google Patents

Description

  The present invention relates to a filter clogging life determination method for an internal combustion engine that determines the clogging life of a fuel filter provided in a fuel pipe of the internal combustion engine based on a pressure detected by a pressure sensor disposed downstream, and an internal combustion engine using the same.

In an internal combustion engine such as a diesel engine, the fuel flowing from the fuel tank to the injection pump and filtered, to remove impurities mixed in the fuel, as shown in FIG. 1, the fuel in the middle of the fuel pipe 11 A filter 14 is provided. In the prior art, this fuel filter is often replaced periodically based on the determination of the distance traveled and the years of use regardless of how it is used or clogged. Therefore, most fuel filters on the market are replaced before reaching the clogging life.

  In relation to the determination of the clogging life of the fuel filter of the internal combustion engine, in the fuel filter upstream of the fuel pump, fuel pressure sensors are provided on the upstream side and the downstream side, and the pressure difference before and after the fuel filter is greater than the upper limit threshold value. There has been proposed a fuel supply control device for an internal combustion engine that activates an alarm device and shifts to an idle operation on the assumption that clogging is unacceptable when it is larger and smaller than a lower limit threshold (see, for example, Patent Document 1).

The filter element detects the fuel pressure in the fuel path downstream of the fuel filter and upstream of the fuel pump, and warns that the pressure is lower or higher than the normal negative pressure range under a predetermined operating condition. There has been proposed a fuel filter abnormality detection device that detects forgetting assembly or assembly of clogged non-genuine filter elements or clogging (for example, see Patent Document 2).
JP 200468776 A JP 2006-63856 A

On the other hand, the present inventors have conducted an experiment on the clogging life of the fuel filter, and the pressure characteristics at the outlet of the fuel filter tend to be as shown in FIG. In this region, it has been found that the filter outlet pressure Po downstream of the fuel filter varies depending on the engine speed Ne and the discharge amount Vp of the fuel boost pump .

That is, as shown in FIG. 2, the engine operating region related to the determination of the clogging life of the fuel filter is roughly divided into three first to third determinations based on the relationship between the filter outlet pressure Po and the engine speed Ne. Divided into regions R1, R2 and R3. In the first determination region R1 where the engine speed Ne is low, the filter outlet pressure Po does not change even if the fuel filter is clogged. Therefore, in the first determination region R1, it is difficult to determine the clogging life due to the filter outlet pressure Po.

In the second determination region R2 where the engine speed Ne is higher than the first determination region R1, the characteristics of the filter outlet pressure Po change due to the influence of the fuel boost pump discharge amount Vp and the engine speed Ne. To do. In the second determination region R2, when the fuel filter is clogged, if the fuel booster pump is continuously discharged (dotted line), the filter outlet pressure Po is reduced the higher the engine speed Ne, the fuel booster pump is full If it is discharge (solid line), the filter outlet pressure Po does not decrease. That is, the filter outlet pressure Po varies greatly depending on the discharge amount Vp of the fuel boost pump . Further, in the third determination region R3 where the engine speed Ne is higher than the second determination region R2, the change in the filter outlet pressure Po due to the discharge amount Vp of the fuel boost pump is small, and as the fuel filter clogging progresses, The filter outlet pressure Po decreases.

Further, in the third determination region R3 where the engine speed Ne is higher than the second determination region R2, the filter outlet pressure Po is less fluctuated due to the discharge amount Vp of the fuel boost pump, and is affected by the engine speed Ne. Changes its characteristics.

  Here, the engine speed is related to the speed of a fuel boost pump (high pressure pump) that raises the fuel to a level higher than the fuel injection pressure, and is used for normal engine control. The engine speed is used instead.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a clogging life of a fuel filter provided in a fuel pipe of an internal combustion engine and a pressure sensor provided on the downstream side of the fuel filter. An object of the present invention is to provide a method for determining the clogging life of a fuel filter of an internal combustion engine that can be accurately determined by a detected pressure, and an internal combustion engine using the same.

A method for determining the clogging life of a fuel filter of an internal combustion engine according to the present invention for achieving the above object is to determine the clogging life of a fuel filter provided in a fuel pipe for supplying fuel from a fuel tank to a fuel injection nozzle. And a control device that determines that the fuel filter has reached the clogging life when a detected pressure of a pressure sensor disposed on the downstream side of the fuel filter is equal to or less than a preset clogging life determination threshold value. In the method for determining a clogging life of a fuel filter of an internal combustion engine, when the engine speed is equal to or lower than a preset first engine speed, the clogging life is not determined, and the first engine having a preset engine speed is determined. If greater than the rotational speed, the fuel booster Pont provided with the plugging life determination threshold to the fuel piping downstream of the pressure sensor and the engine speed Calculated based on the discharge amount, a method which is characterized in that the determination of clogging life.

  According to this method, since it is performed by one pressure sensor on the downstream side of the fuel filter regardless of the differential pressure before and after the fuel filter, the system for determining the clogging life can be simplified. In addition, the clogging life judgment threshold, which is the criteria for clogging life, is calculated based on the engine speed, so the clogging life judgment algorithm is relatively simple and the clogging life is accurately determined. become able to.

Wherein the clogging life determination method for a fuel filter of the internal combustion engine, greater than the first engine speed the engine speed preset in the second case follows the engine speed set in advance, the engine speed Correction is performed to increase the clogging life determination threshold calculated based on the discharge amount of the fuel booster pump as the total fuel supply fuel increases.

  According to this method, the clogging life determination threshold value is increased with the increase in the total fuel supply even in an engine operating state in which the discharge amount of the fuel boost pump greatly fluctuates. It becomes possible to determine whether or not the lifetime is reached.

  In the method for determining the clogging life of the fuel filter of the internal combustion engine, after determining that the fuel filter has reached the clogging life in the clogging life determination, the detected pressure of the pressure sensor is When the predetermined filter replacement determination threshold value that is larger than the clogging life determination threshold value is reached, the total fuel supply value is reset.

  According to this configuration, even after determining that the fuel filter has reached the clogging life, it is automatically integrated after confirming that the fuel filter has been replaced and the filter outlet pressure has been restored. Since the value of the fuel amount is reset, it is not necessary to perform the resetting operation, and it is possible to prevent erroneous determination of the clogging life due to forgetting to reset.

In the method for determining the clogging life of the fuel filter of the internal combustion engine, the speed of the fuel supply pump provided in the fuel pipe upstream of the fuel filter is used instead of the engine speed. According to this configuration, the fuel injection amount at the fuel injection nozzle, that is, the rotation speed of the fuel supply pump that is closely related to the fuel volume that passes through the fuel filter is used instead of the engine rotation speed, so that the clogging is further performed. The accuracy of life determination can be improved. When the engine speed is used, it is not necessary to newly detect the speed of the fuel supply pump or incorporate it into the control because the engine speed is used in normal engine operation control.

In order to achieve the above object, an internal combustion engine of the present invention is arranged downstream of the fuel filter in determining the clogging life of a fuel filter provided in a fuel pipe for supplying fuel from a fuel tank to a fuel injection nozzle. In the internal combustion engine provided with the control device that determines that the fuel filter has reached the clogging life when the detected pressure of the pressure sensor is equal to or less than a preset clogging life determination threshold, the control device includes: When the engine speed is equal to or lower than the preset first engine speed, the clogging life is not determined. When the engine speed is greater than the preset first engine speed, the clogging life is determined. the threshold value is calculated based on the discharge amount of the fuel booster pump provided in the fuel pipe on the downstream side of the pressure sensor and the engine speed, and determines clogging life Configured.

In the internal combustion engine, when the engine speed is larger than the first engine speed set in advance and equal to or lower than the second engine speed set in advance, the engine speed and the fuel pressure increase are set. The clogging life determination threshold calculated based on the discharge amount of the pump is corrected so as to increase as the total fuel supply increases.

  In the internal combustion engine, after the control device determines that the fuel filter has reached the clogging life in the clogging life determination, the detected pressure of the pressure sensor is changed to the clogging life. It is configured to reset the value of the total fuel supply fuel when a predetermined filter replacement determination threshold value that is larger than the life determination threshold value is reached.

In the internal combustion engine described above, the rotational speed of the fuel supply pump provided in the fuel pipe upstream of the fuel filter is used instead of the engine rotational speed.

  According to these internal combustion engines, the method for determining the clogging life of the fuel filter of the internal combustion engine described above can be implemented, and the same effects can be achieved.

  According to the fuel filter clogging life determination method and the internal combustion engine using the same according to the present invention, the clogging life of the fuel filter provided in the fuel pipe of the internal combustion engine is determined depending on the engine speed. By changing the calculation method of the life judgment threshold value, the clogging life judgment threshold value is calculated using not only the engine speed but also the discharge amount of the fuel boost pump in the preset range. The clogging life of the fuel filter can be accurately determined even with the pressure detected by one pressure sensor provided in the fuel filter. Therefore, it is possible to use the fuel filter until it reaches the end of its life by accurately determining the clogged state of the fuel filter and notifying the user with a warning light or the like.

Hereinafter, a method for determining a clogging life of a fuel filter of an internal combustion engine according to an embodiment of the present invention and an internal combustion engine using the same will be described with reference to the drawings. FIG. 1 shows the configuration of a clogging life determination system for a fuel line and a fuel filter of an internal combustion engine according to an embodiment of the present invention.

As shown in FIG. 1, a fuel line 10 of an internal combustion engine is a line connecting a fuel tank 12 and a fuel injection nozzle (injector) 18 with a fuel pipe 11. A fuel supply pump (feed pump) 13, a fuel filter 14, a pressure sensor 15, a fuel boost pump (high pressure pump) 16, and a common rail 17 are disposed.

 The pressure signal detected by the pressure sensor 15 is input to a control device 20 called an ECU (Engine Control Unit) that controls the operation of the internal combustion engine. The detection pressure Pf obtained from this pressure signal is compared with the filter clogging life determination threshold value Pc1 by the clogging life determination means incorporated in the control device 20, and the clogging life of the fuel filter 14 is determined. If it is determined in this determination that the fuel filter 14 is clogged and has reached the end of its service life, a warning signal is output, and the warning lamp 21a is blinked on the meter panel 21, etc. Warn the user (driver) that the clogging life has been reached. The control device 20 outputs an injection instruction signal to control fuel injection in the fuel injection nozzle 18 provided in the cylinder.

  Next, a clogging life determination method of the clogging life determination means incorporated in the control device 20 will be described with reference to FIGS.

2 to 4, the filter outlet pressure Po (vertical axis) is shown based on the engine speed Ne (horizontal axis). The filter outlet pressure Po affects the discharge amount Vp of the fuel boost pump 16 and the influence of clogging. The change in response is shown by four lines. A thin dotted line indicated by Po1 indicates a non-ejection time and a new product, and a thin solid line indicated by Po2 indicates a full discharge and a new time. A thick dotted line indicated by Po3 indicates no discharge and the clogging life, and a thick solid line indicated by Po4 indicates full discharge and the clogging life.

2 to 4, in the first determination region R1, actually Po1 and Po3, Po2 and Po4, and in the third determination region R3, actually Po1, Po2, and Po3. Although Po4 substantially overlaps, the difference is greatly enlarged and schematically shown for easy understanding. The same applies to Po2 and Po4 in the second determination region R2.

In this clogging life determination method, as shown in FIGS. 2 and 3, the operating range of the internal combustion engine is changed to the first to third determination regions R1, R2, and R3 for clogging life determination based on the engine speed Ne. Divide. When the engine speed Ne is equal to or lower than the first engine speed Ne1 set in advance, the first determination region R1 is set. Further, when the engine speed Ne is larger than the preset first engine speed Ne1 and is equal to or less than the preset second engine speed Ne2, the second determination region R2 is set. Furthermore, when the engine speed Ne is larger than the second engine speed Ne2 , the third determination region R3 is set.

  Next, when it is determined that the operating region of the internal combustion engine when the clogging life determination is to be performed is in the first determination region R1 based on the engine speed Ne, the fuel filter 14 may be clogged. Since the detected pressure Pf does not change and the clogging life cannot be determined, the operating region of the internal combustion engine enters the second determination region R2 or the third determination region R3 without determining the clogging life. Wait for.

When it is determined that the operating region of the internal combustion engine is in the second determination region R2 based on the engine speed Ne, the clogging life determination threshold value Pc1 is set to the engine speed Ne and the discharge amount Vp of the fuel booster pump 16. The clogging life determination threshold value Pc1 is corrected according to the total fuel supply (total fuel injection amount: integrated fuel flow rate) Qs, and the clogging life is determined. In this clogging life determination, when the detected pressure Pf detected by the pressure sensor 15 is equal to or less than the clogging life determination threshold value Pc1 (Pf ≦ Pc1), it is determined that the clogging life is reached, and the others (Pf> Pc1) In the case of, it is determined that the clogging life is not reached.

The reason for making this determination will be described. In the second determination region 2, as shown in FIG. 2, the manner in which the filter outlet pressure Po changes varies depending on the discharge amount Vp of the fuel booster pump 16 and the engine speed Ne. When the fuel filter 14 has a clogged lifetime, when the fuel boost pump 16 does not discharge, that is, when the discharge amount Vp of the fuel boost pump 16 is zero (dotted line), the higher the engine speed Ne, the higher the filter outlet pressure. When Po decreases and the fuel boost pump 16 is fully discharged, that is, when the discharge amount Vp of the fuel boost pump 16 is full (solid line), the filter outlet pressure Po does not decrease. That is, the amount of decrease in the filter outlet pressure Po greatly varies depending on the discharge amount Vp of the fuel boost pump 16.

  Therefore, as shown in FIG. 3, the clogging life judgment threshold value Pc1 is calculated in consideration of the filter outlet pressures (thick lines in FIG. 2) Po3, Po4 and the discharge amount Vp of the fuel booster pump 16 at the filter clogging life. If the detected pressure Pf drops below that, the fuel filter 14 is determined to have reached the clogging life.

However, in the second determination region R2, the filter outlet pressure Po greatly varies depending on the discharge amount Vp of the fuel boost pump 16, so that the fuel filter 14 is operated during the operation when the discharge amount Vp of the fuel boost pump 16 varies greatly. Even when it is new (thin line), the filter outlet pressure Po is lowered by the discharge amount Vp of the fuel booster pump 16, and therefore it may be determined that the clogging life has been reached. Therefore, as shown in FIG. 3, correction is performed to increase the value of the clogging life determination threshold value Pc1 in accordance with the total fuel supply fuel Qs obtained by integrating the fuel amount (fuel injection amount) Q that has passed through the fuel filter 14.

  In other words, foreign matter generated in the engine is also present in the thing captured by the fuel filter 14, but most of it is contained in the fuel supply, so that it is supplied after replacing the fuel filter 14 with a new one. It is considered that clogging progresses as the fuel amount, in other words, the total fuel amount Qs that is the total amount of fuel filtered by the fuel filter 14 (integrated fuel flow rate, total fuel injection amount) increases. Therefore, the clogging life is increased so that the clogging life determination threshold value Pc1 increases as the total fueling fuel Qs increases so that it is easier to determine that the clogging life has been reached as the total fueling fuel Qs increases. The determination threshold value Pc1 is corrected.

Next, when it is determined that the operation region of the internal combustion engine is in the third determination region R3 based on the engine speed Ne, the clogging life determination threshold value Pc1 is set to the engine speed Ne and the discharge amount Vp of the fuel booster pump 16. To calculate the clogging life. In this clogging life determination, when the detected pressure Pf detected by the pressure sensor 15 is equal to or less than the clogging life determination threshold value Pc1 (Pf ≦ Pc1), it is determined that the clogging life is reached, and the others (Pf> Pc1) In the case of, it is determined that the clogging life is not reached.

In the third determination region R3, when the fuel filter 14 is clogged, the filter outlet pressure Po decreases. In the third determination region R3, the influence of the filter outlet pressure Po due to the discharge amount Vp of the fuel boost pump 16 is small, and the change of the filter outlet pressure Po due to the change of the discharge amount Vp of the fuel boost pump 16 is small. Therefore, the clogging life judgment threshold value Pc1 is set according to the filter outlet pressure ( thin line in FIG. 3 ) Po3 and Po4 at the clogging life of the fuel filter 14 (thick line), and the calculation is performed based on this.

  In these clogging life determinations, when it is determined that the state of the fuel filter 14 is clogging life, a warning signal is output from the control device 20 to the meter panel 21, as shown in FIG. The warning lamp 21a is flashed or the like to warn the user that the fuel filter 14 is clogged and needs to be replaced.

  When the fuel filter 14 is replaced by the user or the like, it is necessary to reset the total fuel supply fuel Qs used in the correction of the clogging life determination threshold value Pc1 in the second determination region R2. Therefore, after the replacement, the filter outlet pressure Po returns to the pressures Po1 to Po2 at the time of a new product, and therefore the detected pressure Pf is checked after determining the filter clogging life after replacement of the fuel filter 14.

  In this case, the filter replacement determination threshold value Pc2 is set in advance for the engine speed Ne and the discharge amount Vp of the fuel booster pump 16 in accordance with the new pressures Po1 to Po2 as shown in FIG. From this setting data, the filter replacement determination threshold value Pc2 is calculated based on the engine speed Ne and the discharge amount Vp of the fuel boost pump 16, and the detected pressure Pf rises above the calculated filter replacement determination threshold value Pc2. If (Pf ≧ Pc2), it is determined that the filter has been replaced, and the total fuel supply fuel Qs is reset to zero and reset. In other cases (Pf <Pc2), no reset is performed.

  The filter replacement determination threshold value Pc2 is set in two first to second determination regions R1a and R2a according to the engine speed Ne.

  A series of determination processes is shown by a logic circuit in FIG. In S1, in order to improve the accuracy of the clogging life determination, the total refueling fuel Qs that is the fuel flow rate that has passed through the fuel filter 14 is calculated by integrating the fuel injection amount Q.

In S2, since the filter outlet pressure Po changes depending on the engine speed Ne and the discharge amount Vp of the fuel boost pump 16 , the clogging life determination threshold value is referred to with reference to a preset data map or the like from the engine speed Ne or the like. Pc1 is calculated. In S2, when the engine operating region is in the second determination region R2, the clogging life determination threshold value Pc1 calculated based on the engine speed Ne and the discharge amount Vp of the fuel booster pump 16 is set. , Correction is made to gradually increase as the total refueling fuel Qs calculated in S1 increases.

In S3, when the detected pressure Pf falls below the clogging life determination threshold value Pc1 (YES: Pf ≦ Pc1), it is determined that the fuel filter 14 has reached the clogging life, and the process goes to S4 and S5. In S4, in response to the determination that the clogging life is reached, a signal for turning on the warning lamp 21a is output to the meter panel 21. The user receives this warning and replaces the fuel filter 14. If the detected pressure Pf is greater than the clogging life determination threshold value Pc1 in S3 (NO: Pf> Pc1), it is determined that the fuel filter 14 has not reached the clogging life, and the process goes to S1 .

In S5, since it is necessary to reset the total fuel supply fuel Qs after the filter replacement, the filter replacement determination threshold value Pc2 is calculated. Thereafter, the process goes to S6, and when the detected pressure Pf rises above the filter replacement determination threshold value Pc2 (YES: Pf ≧ Pc2), it is determined that the filter has been replaced, and the total fuel supply Qs is automatically reset in S7. . Thereafter, the process returns to S1 . If the detected pressure Pf is smaller than the filter replacement determination threshold value Pc2 (NO: Pf <Pc2), it is determined that the filter has not been replaced, and the process directly returns to S1 . In this case, the signal for turning on the warning lamp 21a in S4 is repeatedly output until the filter is replaced.

  In the above description, the engine rotation speed Ne is used to classify the engine operating range, and the clogging life determination threshold value Pc1 and the filter replacement determination threshold value Pc2 are calculated based on the engine rotation speed Ne. However, the rotational speed of the fuel supply pump (feed pump) 13 that is closely related to the filter outlet pressure can be used instead of the engine rotational speed Ne.

  According to the method for determining the clogging life of the fuel filter of the internal combustion engine and the internal combustion engine using the same, in the determination of the clogging life of the fuel filter 14 provided in the fuel pipe 11 of the internal combustion engine, the clogging life is determined based on the engine speed Ne. Since the calculation method of the clogging life determination threshold value Pc1 is changed, it is possible to accurately determine the clogging life of the fuel filter 14 even with the detection pressure Pf of one pressure sensor 15 provided on the downstream side of the fuel filter 14. it can. Therefore, the fuel filter 14 can be used until the end of its life by accurately determining the clogged state of the fuel filter 14 and notifying the user with the warning lamp 21a or the like.

It is a figure which shows the structure of the fuel line of the internal combustion engine of embodiment which concerns on this invention. It is a figure which shows the relationship between an engine speed and filter outlet pressure. It is a figure which shows the relationship between a filter exit pressure characteristic and a filter clogging lifetime determination threshold value. It is a figure which shows the relationship between a filter exit pressure characteristic and a filter exchange determination threshold value. It is a figure which shows the logic circuit of the clogging lifetime determination method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel line 11 Fuel piping 12 Fuel tank 13 Fuel supply pump (feed pump)
14 Fuel Filter 15 Pressure Sensor 16 Fuel Booster Pump 17 Common Rail 18 Fuel Injection Nozzle (Injector)
20 control unit (ECU)

Claims (8)

In the determination of the clogging life of the fuel filter provided in the fuel pipe for supplying fuel from the fuel tank to the fuel injection nozzle, the pressure detected by the pressure sensor arranged on the downstream side of the fuel filter is set to the clogging life set in advance. In a method for determining a clogging life of a fuel filter of an internal combustion engine, comprising a control device that determines that the fuel filter has reached a clogging life when the fuel filter is below a determination threshold,
When the engine speed is equal to or lower than the preset first engine speed, the clogging life is not determined. When the engine speed is greater than the preset first engine speed, the clogging life is determined. A fuel filter for an internal combustion engine characterized in that a threshold value is calculated based on an engine speed and a discharge amount of a fuel boost pump provided in the fuel pipe downstream of the pressure sensor, and a clogging life is determined. Clogging life judgment method. When the engine speed is larger than the preset first engine speed and equal to or less than the preset second engine speed, the clogging life calculated based on the engine speed and the discharge amount of the fuel boost pump 2. The method for determining a clogged life of a fuel filter for an internal combustion engine according to claim 1, wherein the correction is performed such that the determination threshold value is increased in accordance with an increase in total fuel supply fuel. After the determination that the fuel filter has reached the clogging life in the clogging life determination, a preset filter replacement determination threshold value that is detected by the pressure sensor is larger than the clogging life determination threshold value 3. The method for determining a clogging life of a fuel filter for an internal combustion engine according to claim 2 , wherein the value of the total fuel supply fuel is reset when the above condition is reached. 4. The fuel filter for an internal combustion engine according to claim 1 , wherein the speed of the fuel supply pump provided in the fuel pipe upstream of the fuel filter is used instead of the engine speed. Clogging life judgment method. In the determination of the clogging life of the fuel filter provided in the fuel pipe for supplying fuel from the fuel tank to the fuel injection nozzle, the pressure detected by the pressure sensor arranged on the downstream side of the fuel filter is set to the clogging life set in advance. In an internal combustion engine provided with a control device for determining that the fuel filter has reached the clogging life when the determination threshold value or less is reached,
When the engine speed is equal to or lower than the first engine speed set in advance, the clogging life is not determined, and when the engine speed is higher than the first engine speed set in advance, An internal combustion engine characterized in that the clogging life determination threshold value is calculated based on an engine speed and a discharge amount of a fuel booster pump provided in the fuel pipe on the downstream side of the pressure sensor to determine a clogging life. organ. When the engine speed is greater than the preset first engine speed and equal to or less than the preset second engine speed, the control device calculates based on the engine speed and the discharge amount of the fuel boost pump. 6. The internal combustion engine according to claim 5, wherein a correction is made to increase the clogging life determination threshold value as the total refueling fuel increases. After the control device determines that the fuel filter has reached the clogging life in the clogging life determination, the pressure detected by the pressure sensor is preset to be greater than the clogging life determination threshold value. The internal combustion engine according to claim 6 , wherein a value of the total refueling fuel is reset when the filter replacement determination threshold value is exceeded. 8. The internal combustion engine according to claim 5, wherein the control device uses a rotation speed of a fuel supply pump provided in the fuel pipe upstream of the fuel filter instead of the engine rotation speed. organ.

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