JP4439388B2 - Fuel injection amount control device - Google Patents

Description

  The present invention relates to a fuel injection amount control device that detects an abnormality in a rack position detection signal obtained from rack position detection means for detecting the position of a rack that adjusts the fuel injection amount.

A general fuel injection amount control apparatus 1 for supplying fuel to the engine will be described with reference to FIG. The fuel injection amount control device 1 is based on an electric control unit (hereinafter referred to as “ECU”) as an example of rack control means based on a rack position and a target rack position obtained from a rack position sensor 20 as an example of rack position detection means. ) 10 controls the rack 35 to the target rack position by adjusting the amount of current of the proportional solenoid 30 that drives the rack 35. Further, the connection between the ECU 10 and the rack position sensor 20 is relayed by a sensor amplifier 41, a harness, and the like. Since the sensor amplifier 41 is connected to the battery 42 and the ground point 43, the ECU 10 and the like acquire electric power. Grounding can be ensured. By the way, in the fuel injection amount control device 1, abnormalities such as disconnection / short circuit inside the rack position sensor 20 or disconnection / short circuit of the sensor amplifier 41 or the harness provided between the ECU 10 and the rack position sensor 20 are sometimes obtained. May occur. As such an abnormality detection method, for example, there is a method disclosed in Patent Document 1 below. In Patent Document 1, when the engine is started, the rack is moved to a predetermined position, and at this time, it is determined whether or not the output of the rack position sensor 20 is within a predetermined range. The thing is described. In other words, when the engine is started, when the rack position sensor 20 cannot normally output a value corresponding to the rack being in a predetermined position and an abnormal rack position detection signal is output, an abnormality such as disconnection or short circuit occurs. It is judged that it did.
Japanese Utility Model Publication No. 6-43238

  However, the technique disclosed in Patent Document 1 detects an abnormality only when the engine is started, and does not detect an abnormality during operation.

  On the other hand, the applicant has conventionally performed the following processing. The normal correlation between the rack position detection signal (hereinafter referred to as “Ract”) that is the output of the rack position sensor 20 in the normal state and the rack control signal (hereinafter referred to as “Qout”) that is the command value for rack drive control is shown in FIG. As shown in FIG. 6, the relationship is such that Ract increases with increasing Qout (for example, a proportional relationship as indicated by a one-dot chain line 53), and the intersections are, for example, point 51 and point 52. Therefore, for example, when Rout is a value other than R1 when Qout is Q1, or when Ract is a value other than R2 when Qout is Q2, an abnormality may be determined. However, since the range of the normal state is unknown in the relationship between Qout and Ract, in order to avoid erroneous detection, only an actual extreme value was judged as abnormal. An example of an extreme value in this case is when the relationship between Ract and Qout exists in the abnormal region 45 or the abnormal region 46. The abnormal region 45 is when the rack position sensor 20 outputs a large value that cannot normally occur although Qout should be near 0 when Qout is normal. is there. In the abnormal region 46, when Qout is near the maximum value, if normal, Ract should be close to the maximum value, but the rack position sensor 20 outputs a small value that cannot normally occur. Is the case.

  However, the abnormality detection process as described above has the following problems. For example, even if a disconnection occurs between the rack position sensor 20 and the sensor amplifier 41 in a situation where the relationship between Ract and Qout is normally at a position such as point 51 or 52, the relationship between Ract and Qout. It is known that it does not immediately fit in the abnormal region 45 or the abnormal region 46 and takes time. For example, it is known that the relationship between Ract and Qout travels along the paths (1) to (3) over time and reaches the abnormal region 45 or the abnormal region 46. This is because the control of the rack 35 is performed based on feedback control as shown in FIG. This feedback control will be described. A deviation between a target rack position (hereinafter referred to as “Rset”) which is a target value of the rack position sensor 20 and Ract is input to the ECU 10 which is rack control means. The ECU 10 calculates Qout as an operation amount and inputs it to the rack driving means 11 that generates a rack driving current to be supplied to the coil of the proportional solenoid. Next, the rack driving means 11 drives and controls the rack 35 by supplying a rack driving current to the proportional solenoid, and the rack position sensor 20 detects the result as Ract. The Ract detected by the rack position sensor 20 is again compared with Rset, the deviation is input to the ECU 10, and the above-described processing is repeated. Since such a round of feedback control is performed, when an abnormality occurs, it takes time until the relationship between Ract and Qout falls within the abnormal region 45 or the abnormal region 46, thereby delaying abnormality detection and Since the engine cannot be controlled normally, a phenomenon may occur in which the output of the engine rapidly increases or decreases.

  Therefore, the present invention has been made in view of the above circumstances, and the object of the present invention is to open and short-circuit the relationship between the rack position detection signal (Ract) and the rack control signal (Qout) quickly and accurately. It is an object to provide a fuel injection amount control device that detects abnormalities such as the above.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

According to another aspect of the present invention, the rack control signal is calculated based on the rack position detection means for detecting the position of the rack for adjusting the fuel injection amount, the rack position detection signal obtained from the rack position detection means, and the target rack position. In a fuel injection amount control device comprising a rack control means, a normal correlation storing a normal correlation which is a relationship between a normal rack control signal and a normal rack position detection signal at each rack position in a normal state obtained in advance a correlation storage means, the obtained by position detecting means and the rack controller means, the relationship between the rack control signal and the position detecting signal, the normal correlation storage corresponding to the detected rack position If not within the scope of the means, and abnormality detection means for the position detecting signal is output to be abnormal, but having a That.

  According to a second aspect of the present invention, the normal correlation stored in the normal correlation storage means is set in consideration of the influence of the ambient temperature in the vicinity of the rack as a boundary condition.

  As effects of the present invention, the following effects can be obtained.

The rack position detection means for detecting the position of the rack for adjusting the fuel injection amount, the rack position detection signal obtained from the rack position detection means, and the rack control signal based on the target rack position. In a fuel injection amount control device comprising a rack control means for calculating, a normal correlation which is a relationship between a normal rack control signal and a normal rack position detection signal at each rack position in a normal state obtained in advance is stored to a normal correlation storing means, the obtained by position detecting means and the rack controller means, the relationship of the rack control signal and said position detecting signal, the normal correlation corresponding to the detected rack position If not within the scope of the relationship storing means, an abnormality detection means for the position detecting signal is output to be abnormal, so it comprises a It is possible to clearly define the normal correlation, and even when the engine is operating, the relationship between the rack control signal and the rack position detection signal at that time is not within the normal correlation range. Before the rack position reaches the limit in the abnormal state, it is possible to notify the outside that a disconnection / short circuit abnormality has occurred in the rack position detection means or the like.

  According to the configuration of claim 2, it is possible to determine a normal correlation that matches the characteristics of the fuel injection amount control device and the engine. Therefore, the abnormality detection process according to the characteristics of the fuel injection amount control device and the engine is performed. This makes it possible to reduce erroneous detection.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings for understanding of the present invention. The following best mode for carrying out the present invention is an example embodying the present invention, and is not intended to limit the technical scope of the present invention. FIG. 1 is a schematic configuration diagram showing a hardware configuration of a general fuel injection amount control device, FIG. 2 is an explanatory diagram of an abnormal region in the prior art, and FIG. 3 is a block diagram of feedback control of the fuel injection amount control device. 4 is a diagram showing a map 50 as an example of normal correlation stored in the normal correlation storage means, FIG. 5 is a flowchart showing an example of a series of processing performed by the ECU 10, and FIG. 6 is normal correlation storage. It is the figure which showed the map 60 which is an example of the normal correlation memorize | stored in a means.

  First, a schematic hardware configuration of a fuel injection amount control device 1 according to the best mode for carrying out the present invention will be described with reference to FIG. Note that the hardware configuration of the fuel injection amount control device 1 described here is the same as that of the conventional device described above, but will be described in detail again. The fuel injection amount control device 1 mainly includes a rack position sensor 20, an ECU 10, a proportional solenoid 30, and the like. The rack position sensor 20 is an example of a rack position detection stage that detects the position of the rack 35 that adjusts the fuel injection amount of the fuel injection amount control device 1 and outputs the detection result as a rack position detection signal (Ract). is there. The ECU 10 is an example of rack control means for calculating a rack control signal (Qout) for controlling the rack 35 based on the Ract obtained from the rack position sensor 20 and the target rack position (Rset). Here, the ECU 10 integrally incorporates functions such as a CPU, ROM, and RAM, and can perform processing such as storage, calculation, and output as a single unit. The proportional solenoid 30 controls driving of the rack 35 by a rack driving current generated based on Qout calculated by the ECU 10, and is connected to the ECU 10 (dashed line). Further, the connection between the ECU 10 and the rack position sensor 20 is relayed by a sensor amplifier 41 or a harness as shown in FIG. 1, and since the sensor amplifier 41 is connected to the battery 42 and the grounding point 43, the ECU 10 etc. Can acquire power and ensure grounding.

<Normal correlation storage means, abnormality detection means>
Further, the ECU 10 serves as a normal correlation storage unit and an abnormality detection unit. The normal correlation storage means stores a normal correlation which is a relationship between a normal rack control signal obtained in a normal state and a normal rack position detection signal. Such a normal correlation is obtained in advance, for example, in the research and development stage of the fuel injection amount control device 1, and can be stored in the ECU 10 as a map 50 surrounded by a closed curve as shown in FIG. Since the relationship between Ract and Qout is such that Ract also increases as Qout increases, if the rack drive current is uniquely determined by Qout, the normal correlation should be represented by one normal curve. . However, because the rack drive current changes even if Qout is the same due to a change in the resistance value of the proportional solenoid 30 due to an increase in the ambient temperature of the fuel injection amount control device 1, the correlation between Ract and Qout varies. The normal correlation is defined as a range surrounded by a closed curve as in the map 50. Abnormality detection means means a rack when the relationship between the rack control signal (Qout) and the rack position detection signal (Ract) during operation obtained by the rack position sensor 20 and the ECU 10 is not within the normal correlation range. It outputs when the position detection signal is abnormal. In this case, outputting that the rack position detection signal is abnormal can be performed by separately providing a display unit, an operation unit, and the like in the ECU 10 and outputting an abnormality message to the display unit and the operation unit. it can. By configuring as described above, it is possible to clearly determine the normal correlation. Therefore, even when the engine is operating, the rack position detection signal (Ract) and the rack control signal ( When the relationship with Qout) is not within the range of the normal correlation, it is possible to notify the outside that a disconnection / short circuit abnormality has occurred in the rack position sensor 20 or the like. In the above configuration, when the relationship between the rack position detection signal (Ract) and the rack control signal (Qout) is not within the range of the normal correlation, an abnormality such as disconnection or short circuit has occurred in the rack position sensor 20 or the like. Therefore, compared with the conventional abnormal areas 45 and 46 described above, the area for determining the abnormality can be expanded, and the response delay when the following feedback control is performed. It is possible to prevent the delay of abnormality detection due to the above.

<Control system>
The fuel injection amount control device 1 configured in this way controls the deviation between Rset and Ract to be zero by performing feedback control as shown in FIG. Here, the feedback control shown in FIG. 3 will be briefly described again. The ECU 10 calculates Qout based on the deviation between Rset and Ract and inputs it to the rack driving means 11. The rack driving means 11 supplies a rack driving current to the proportional solenoid 30 to drive and control the rack 35. As a result of this drive control, the rack position sensor 20 is detected as Ract, and the Ract is compared with Rset, and the deviation is input to the ECU 10 again. Such a round of feedback control is repeatedly performed, and the ECU 10 performs processing according to a flowchart as shown in FIG. 5 for each calculation cycle.

<Flowchart>
First, the ECU 10 obtains a map 50 as an example of normal correlation from the built-in ROM or the like when the power is turned on, and loads the map 50 by developing it in the built-in RAM or the like (S10). Then, the ECU 10 obtains a rack position detection signal (Ract) and a target rack position (Rset) obtained from the rack position sensor 20 for each predetermined control cycle, performs the above feedback control, and performs the following processing ( S15). The ECU 10 determines whether the intersection of the rack position detection signal (Ract) value obtained from the rack position sensor 20 and the calculated rack control signal (Qout) value is within the range surrounded by the closed curve of the map 50. Judgment is made (S20). In this determination, if it is determined that the intersection of Ract and Qout is not within the range of the map 50, the process proceeds to step S30. On the other hand, it is determined that the intersection of Ract and Qout is within the range of the map 50. In that case, the process of step S20 is performed again. Then, the ECU 10 determines whether or not a predetermined time has passed in a state where the intersection of Ract and Qout is not within the range of the map 50 (S30). If it is determined that the predetermined time has elapsed, the process proceeds to step S40. On the other hand, if it is determined that the predetermined time has not elapsed, the process proceeds to step S20. The ECU 10 determines that the predetermined time has elapsed with the intersection of Ract and Qout not being within the range of the map 50 in step S30, and thus determines that the rack position detection signal is abnormal, An abnormality message is output to the operation unit or the like (S40). Since the processing as described above is performed, when the rack position sensor 20 or the like is normal, the intersection of Ract and Qout temporarily deviates from the range of the map 50 indicating the normal correlation due to an unexpected disturbance or the like. Even if a situation occurs, it is possible to prevent immediately from determining that there is an abnormality and outputting that fact. That is, it is possible to prevent erroneous detection that the rack position sensor 20 or the like is abnormal although it is normal.

<Boundary conditions>
In the above description, as an example of the normal correlation, a case has been described in which the map 50 in which the proportional relationship between Ract and Qout is simply given a width is used. In the following, the map is defined as a boundary condition that takes into account the effect of changes in the ambient temperature due to the engine or the like provided in the vicinity of the rack 35 in determining the map with a range of the proportional relationship between Ract and Qout. An example of the case will be described with reference to FIG. A normal curve that is an example of a normal correlation between Ract and Qout when the vicinity of the rack 35 is at room temperature is defined as a room temperature curve L1, for example. In this case, the normal curve when the temperature near the rack 35 is lower than the normal temperature can be defined as a low temperature curve L2 drawn above the normal temperature curve L1, while the normal curve when the temperature near the rack 35 is higher than the normal temperature. The curve can be defined as a high temperature curve L3 drawn below the normal temperature curve L1. In addition, the normal curve at the limit temperature at which the fuel injection amount control device 1 can be used lower than the low temperature curve L2 can be defined as the limit low temperature curve L4 drawn above the low temperature curve L2, while the high temperature A normal curve at a limit temperature higher than the curve L3 and at which the fuel injection amount control apparatus 1 can be used can be defined as a limit high temperature curve L5 drawn below the high temperature curve L3. In this way, the range between the uppermost critical low-temperature curve L4 and the lowermost critical high-temperature curve L5 can be determined as a map of an example of normal correlation, but may be further determined as follows. . Here, in consideration of the temperature and the measurement error of the rack position sensor 20, the upper error curve L6 and the lower error curve L7 are further defined on the upper side and the lower side, and the range between the upper error curve L6 and the lower error curve L7. Can be defined as a map 60 of an example of normal correlation. Further, upper end points P1 and lower end points P2 are defined as upper end points and lower end points P2 in the upper error curve L6, and upper end points P4 and lower end points P3 are defined as upper end points and lower end points in the lower error curve L7. That is, the range of the map 60, which is an example of a normal correlation, can be defined using the upper error curve L6, the lower error curve L7, the two upper end points P1 and P4, and the two lower end points P2 and P3 as boundary conditions. Since the map 60 determined in this manner is a plot of values obtained by measuring the relationship between Ract and Qout for each ambient temperature band when the rack position sensor 20 or the like is in a normal state, the fuel injection amount of the present invention. This can be said to be a normal correlation that matches the characteristics of the control device 1 and the engine. Therefore, the processing according to the flowchart described in FIG. 5 is performed, so that it is possible to perform abnormality detection processing according to the characteristics of the fuel injection amount control device 1 and the engine, thereby reducing erroneous detection. Is possible. In addition, in order to reduce the processing load and calculation load when the ECU 10 loads the map 60, the map determination method can be simplified as follows. For example, an intermediate point P5 and an intermediate point P6 that are substantially intermediate positions of the upper error curve L6 and the lower error curve L7 are determined. In this case, the range surrounded by the intermediate point P5 and the intermediate point P6 and the four points (P1 to P4) already described above may be determined as a map which is an example of normal correlation. Unlike the case where the upper error curve L6 and the lower error curve L7 are used to determine the map only by the points in this way, the map is simplified, so the load on the ECU 10 is reduced and the processing speed is increased. Can be achieved.

The schematic block diagram which showed the structure of the hardware of a general fuel injection amount control apparatus. Explanatory drawing of the abnormal area | region in a prior art. The block diagram of the feedback control of a fuel injection amount control apparatus. The figure which showed the map 50 which is an example of the normal correlation memorize | stored in a normal correlation memory | storage means. The flowchart which showed an example of the series of processes which ECU10 performs. The figure which showed the map 60 which is an example of the normal correlation memorize | stored in a normal correlation memory | storage means.

1 Fuel injection amount control device 10 ECU
20 rack position sensor 30 proportional solenoid 35 rack 41 sensor amplifier 50 map 60 map

Claims (2)

Rack position detection means for detecting the position of the rack for adjusting the fuel injection amount; and rack control means for calculating a rack control signal based on the rack position detection signal obtained from the rack position detection means and the target rack position. the fuel injection quantity control apparatus including, in previously obtained normal state, and a normal correlation storing means for storing a normal correlation is a relationship between the normal rack control signal and the normal position detecting signals at each rack position provided, obtained by the position detecting means and the rack controller means, the relationship between the rack control signal and the position detecting signal is not within the scope of the normal correlation storing means corresponding to the detected rack position An abnormality detecting means for outputting that the rack position detection signal is abnormal. Control device.   The fuel injection amount control apparatus according to claim 1, wherein the normal correlation stored in the normal correlation storage means is set in consideration of an influence of an ambient temperature in the vicinity of the rack as a boundary condition.

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