JP4345224B2 - Fuel injection device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel injection apparatus for an internal combustion engine that injects fuel into the internal combustion engine, and more particularly to a fuel injection apparatus for an internal combustion engine that controls a fuel injection amount by overflowing pressurized fuel in a pump chamber of an injection pump via a spill valve. About.
[0002]
[Prior art]
Conventionally, as a fuel injection device that injects high-pressure fuel into an internal combustion engine such as a diesel engine, the fuel in the pump chamber is pressurized by expanding and contracting the pump chamber with a plunger that reciprocates in synchronization with the rotation of the internal combustion engine. One having an injection pump for pumping to an internal combustion engine is known. In this type of fuel injection device, generally, a spill valve is provided in the fuel discharge path communicating with the pump chamber of the injection pump, and the spill valve is opened during fuel pumping from the pump chamber to overflow the fuel. Thus, the fuel injection amount to the internal combustion engine is controlled.
[0003]
However, in such a conventional fuel injection device, if the spill valve is in a closed state, the fuel injection amount cannot be controlled, and a large amount of fuel is supplied to the internal combustion engine. There is a possibility of an overrun condition.
[0004]
Therefore, for example, the technique disclosed in Japanese Patent Application Laid-Open No. 11-324777 detects the rotation fluctuation of the injection pump, and when the detected value exceeds preset rotation fluctuation data, the spill valve is closed. Therefore, the fuel supply to the injection pump was stopped and the operation of the internal combustion engine was stopped just before the overrun state.
[0005]
Here, the preset rotation fluctuation data is rotation fluctuation data set slightly larger than the rotation fluctuation data (machine difference central data) of the injection pump corresponding to the rotation speed of the internal combustion engine and the injection amount command value. In other words, when the spill valve remains closed, a large amount of fuel is supplied to the internal combustion engine, and the rotation of the internal combustion engine is increased, resulting in an overrun state. Further, the rotational fluctuation amount of the internal combustion engine tends to increase in proportion to the rotation of the internal combustion engine and the amount of fuel supplied to the internal combustion engine, and the internal combustion engine can be stopped before the overrun state in consideration of this tendency. It is rotation fluctuation data.
[0006]
[Problems to be solved by the invention]
However, in the technique disclosed in Japanese Patent Application Laid-Open No. 11-324777, the preset rotation fluctuation data is rotation fluctuation data set slightly larger than the machine difference central data, and this data is set uniformly. Therefore, since the data is fixed, it is not possible to cope with the variation in the difference in the drive transmission system between the injection pump and the change over time of the internal combustion engine depending on the internal combustion engine.
[0007]
In other words, the internal combustion engine that has the upper limit of the machine difference variation (belt tension, gear drive backlash) of the drive transmission system with the injection pump is more variable than the internal combustion engine in the center of the machine difference variation even during normal injection. Data is greatly measured. This greatly measured rotation fluctuation data exceeds the preset rotation fluctuation data, and there is a risk that the normal range injection is erroneously determined as abnormal. This tendency of erroneous determination increases with a change with time of the internal combustion engine (an increase in variation due to deterioration).
[0008]
Also, in an internal combustion engine where the machine difference variation in the drive transmission system with the injection pump is at the lower limit, the rotation fluctuation data is measured smaller than the internal combustion engine in the center of the machine difference variation, so the rotation at the time of abnormal injection due to a spill valve failure Variation data is also measured small. As a result, the preset rotation fluctuation data exceeds the rotation fluctuation data at the time of abnormal injection, and there is a possibility that a region where normal injection and abnormal injection cannot be determined may occur.
[0009]
As described above, in the conventional technique, there is a possibility that the normal range of injection is erroneously determined as abnormal, or that normal injection and abnormal injection cannot be determined.
[0010]
An object of the present invention is to provide a fuel injection device for an internal combustion engine that can accurately detect a failure in a closed state of the spill valve so that the internal combustion engine can be stopped before the overrun state occurs. is there.
[0011]
[Means for Solving the Problems]
  In order to solve the above-described problem, according to the fuel injection device for an internal combustion engine according to claim 1 of the present invention, the failure determination means includes an injection pump corresponding to a preset number of revolutions of the internal combustion engine and an injection amount command value. Reference value holding means for storing and holding first data which is rotation fluctuation data at the time of abnormality, and an injection pumpspecificCorrection rotation fluctuation detecting means for calculating corrected rotation fluctuation data from rotation fluctuation data during operation and rotation fluctuation data of the injection pump stored in advance under the same operation conditions as this data, and corrected rotation fluctuation detection means The first data is updated using the corrected rotation fluctuation data detected by the step S2, and the updated second data is updated.Update reference value holding meansReference value learning means for storing and holding, and detecting an abnormality in the rotational fluctuation of the injection pump based on the second data instead of the first data, and determining that the spill valve is in a closed state.The corrected rotation fluctuation detecting means stores, as corrected rotation fluctuation data, rotation fluctuation data corresponding to the rotational speed of the internal combustion engine measured during a specific operation, and pre-stores and holds the rotation fluctuation data under the same operating conditions as the rotation fluctuation data. The rotation fluctuation difference data that is the difference from the rotation fluctuation data corresponding to the rotation speed of the internal combustion engine is calculated,
  The rotational fluctuation data constituting the first data changes according to the magnitude of the injection amount command value, and the update reference value holding means corresponds to the rotational speed of the internal combustion engine measured during the specific operation, In addition, the rotation fluctuation difference data is uniformly reflected on all the rotation fluctuation data when the injection pump is abnormal for the entire injection amount command value, and the reflected data is stored and held as second data.It is characterized by that.
[0012]
That is, when the measured rotation fluctuation data of the injection pump is larger than the second data, it is determined that the spill valve is in a closed state. This second data is calculated from the rotation fluctuation data during normal operation of the injection pump by the corrected rotation fluctuation detection means, and the rotation fluctuation data of the injection pump stored in advance under the same operating conditions as this data. Since the first data is updated using the corrected rotation fluctuation data, the machine difference variation of the injection pump to be measured is absorbed, in other words, the data is not affected by the machine difference variation.
[0013]
  As described above, since the second data in which the machine difference variation is absorbed is used, a failure in the closed state of the spill valve can be accurately detected so that the internal combustion engine can be stopped before the overrun state.
  Further, the measured rotational fluctuation data and the rotational fluctuation data stored and held in advance are both rotational fluctuation data corresponding to the rotational speed of the internal combustion engine, and both rotational fluctuation data are data under the same operating conditions. Thus, rotation fluctuation data can be measured with good reproducibility in correspondence with the rotation speed. Therefore, it is possible to accurately detect the machine difference variation of the measured injection pump.
  Further, as described above, the rotational fluctuation difference data is data for correcting the machine difference variation corresponding to the rotational speed of the internal combustion engine. Therefore, the rotational fluctuation difference data is included in all the rotational fluctuation data in the entire injection amount command value constituting the first data. On the other hand, by uniformly reflecting the rotation fluctuation difference data, it is possible to obtain the second data that is the rotation fluctuation difference data in which the machine difference is accurately corrected over the entire injection amount command value.
[0014]
According to the fuel injection device for an internal combustion engine according to claim 2 of the present invention, the rotation fluctuation data of the injection pump stored and held in advance is used as the rotation fluctuation data of the median difference of the injection pump. Compared to the case of rotational fluctuation data deviating from the median, the data is stable. In other words, the rotational fluctuation data of the machine difference median is calculated from a lot of rotational fluctuation measurement data and is obtained with high reproducibility and stability. However, in the case of rotational fluctuation data deviating from the median value, the reproducibility of the rotational fluctuation data is low and unstable, compared with the rotational fluctuation data of the machine difference median value.
[0015]
  According to the fuel injection device for an internal combustion engine according to claim 3 of the present invention, during specific operationIsWhen no injection pump is used, Either when the rate of change of the rotational speed of the internal combustion engine is below a specified level, or when the rate of change of the accelerator opening of the vehicle is below a specified levelIt is characterized by that.
[0016]
  That is, the rotational fluctuation data to be measured and the rotational fluctuation data stored and held in advance are:For example,The rotation fluctuation data at the same time of no injection was used. Thus, by using the rotation fluctuation data at the time of non-injection, both the rotation fluctuation data measured and the rotation fluctuation data stored and held in advance can be rotation fluctuation data whose measurement conditions are reproducible. Therefore, it is possible to accurately detect the machine difference variation of the measured injection pump.
[0020]
  Of the present inventionClaim 4According to the internal combustion engine fuel injection device described above, when the failure determination means determines the failure in the closed state of the spill valve using the second data stored and held by the update reference value holding means, Rotational fluctuation is detected. If the detected data is greater than or equal to the second data, it is determined that the spill valve is in a closed state. If the detected data is not greater than or equal to the second data, the reference value learning is performed. The means is executed.
[0021]
In other words, in determining the failure of the spill valve in the closed state, the second data that is the rotational fluctuation difference data in which the machine difference is accurately corrected is compared with the detected rotational fluctuation data of the injection pump, and detected. If the rotation fluctuation data of the injection pump is equal to or greater than the second data, it can be determined that the spill valve is in a closed state.
[0022]
Further, if the detected rotation fluctuation data of the injection pump is not equal to or greater than the second data, it can be determined that the failure is not caused in the closed state of the spill valve. In this case, the reference value learning means is executed. Then, by executing this reference value learning means, it is possible to update to the second data that matches the latest state of the internal combustion engine. The second data updated in this way can be data that has absorbed the change over time of the internal combustion engine, in other words, is not affected by the change over time.
[0023]
  Of the present inventionClaim 5According to the described fuel injection device for an internal combustion engine, the failure determination means is configured such that the reference value learning means is repeatedly executed and the spill valve is closed using the latest second data stored and held by the update reference value holding means. It is characterized by determining a failure at
[0024]
As a result, by repeatedly executing the reference value learning means, the second data always matches the latest state of the internal combustion engine, that is, absorbs the change with time, and the failure determination means uses this second data to spill. Determine the failure when the valve is closed. As described above, the failure determination means can accurately detect a failure in the closed state of the spill valve.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a fuel injection device for an internal combustion engine according to an embodiment of the present invention will be described in detail with reference to the drawings.
[0026]
FIG. 1 is a schematic configuration diagram showing the configuration of a fuel injection device for an internal combustion engine according to the present invention. As shown in FIG. 1, the fuel injection device according to the present embodiment is for injecting and supplying fuel into a cylinder of an automobile diesel engine (hereinafter simply referred to as an engine) 2 via a fuel injection valve 4. An injection pump 10 that pumps high-pressure fuel to the fuel injection valve 4 through the fuel pipe 6 and injects fuel from the fuel injection valve 4, and a fuel amount that is pumped from the injection pump 10 to the fuel injection valve 4 (that is, fuel injection amount) And an electronic control unit (hereinafter simply referred to as an ECU) 30 for controlling the components.
[0027]
The injection pump 10 is a well-known distribution type pump that distributes and supplies fuel to each cylinder of the engine 2 (only one cylinder is shown in FIG. 1), and is provided in the pump chamber 12 so as to be capable of reciprocating and rotating. A plunger 14 is provided. A cam plate 16 is attached to the side of the plunger 14 opposite to the pump chamber 12, and a cam roller 18 is in contact with the side of the cam plate 16 opposite to the plunger 14.
[0028]
The plunger 14 rotates at a rate of once per two rotations of the engine 2 in synchronization with the rotation of the engine 2, and a convex portion (face cam) formed on the cam plate 16 rides on the cam roller 18 along with the rotation. Thus, the pump chamber 12 is reciprocated. Further, when the plunger 14 reciprocates in this way, the volume of the pump chamber 12 is expanded / reduced (expanded / reduced), and the volume of the pump chamber 12 is decreased, so that the fuel in the pump chamber 12 is pressurized and the fuel is increased. It is pumped to the injection valve 4.
[0029]
The pump chamber 12 is connected to a supply channel 20 that supplies fuel to the pump chamber 12 and a spill channel 22 that overflows the fuel in the pump chamber 12. The passages 22 communicate with fuel chambers (not shown). A fuel cutoff valve 24 is interposed in the supply flow path 20, and a spill valve 26 is interposed in the spill flow path 22.
[0030]
The fuel cutoff valve 24 and the spill valve 26 are constituted by electromagnetic valves that are switched between open and closed states depending on the energized state of the solenoid. In this embodiment, the spill valve 26 has a structure that closes when the solenoid is energized, and opens when the solenoid is de-energized, and is opened by a biasing force of a spring (not shown). The shut-off valve 24 has a structure that opens when the solenoid is energized and opens when the solenoid is de-energized by a biasing force of a spring (not shown).
[0031]
Next, the engine 2 includes an exhaust pipe 2a through which exhaust gas is discharged and an intake pipe 2b through which intake air (intake air) passes. An intake throttle valve (that is, a throttle valve) 32 is provided on the downstream side of the intake pipe 2b. The throttle valve 32 is a so-called linkless throttle valve, and its opening degree (throttle opening degree) is controlled by the ECU 30 via a throttle actuator 36 that drives the throttle valve 32.
[0032]
In addition, the ECU 30 controls the amount of fuel injected from the injection pump 10 to the engine 2 by opening and closing the spill valve 26 via the drive circuit 38 by controlling the throttle opening through the throttle actuator 36. Microcomputer mainly for CPU, ROM, RAM, etc. for performing volume control, engine stop control for detecting a failure in the closed state of the spill valve 26 and forcibly stopping the engine 2 It is composed of.
[0033]
In order to execute these various controls in the ECU 30, the fuel injection device of the present embodiment includes a rotation speed sensor 40 that detects the rotation speed NE of the engine 2 from the rotation of the plunger 14 in the injection pump 10, and an operation. An accelerator sensor 42 for detecting the amount of depression of an accelerator pedal (not shown) operated by a person (hereinafter referred to as accelerator opening) is provided, and detection signals from the rotation speed sensor 40 and the accelerator sensor 42 are input to the ECU 30. . The ECU 30 is also connected with a failure lamp 44 for notifying the driver when a failure of the spill valve 26 is detected. The rotation speed sensor 40 is a known sensor that generates a pulse signal at every predetermined rotation angle of the plunger 14 (and thus the engine 2).
[0034]
Next, among various control processes executed in the ECU 30, a process executed for performing the above-described fuel injection amount control and engine stop control will be described with reference to flowcharts shown in FIGS. First, FIG. 2 is a flowchart showing a spill valve opening / closing process executed in the ECU 30, that is, a spill valve opening / closing process repeatedly executed after the engine 2 is started in order to control the fuel injection amount.
[0035]
In this spill valve opening / closing process, first, in S110 (S represents a step), from a rotational speed NE detected by the rotational speed sensor 40 and an accelerator opening ACCPF detected by the accelerator sensor 42, a map or the like (not shown) is displayed. Based on this, an injection amount command value QFIN is calculated. In the subsequent S120, the closing timing QPANGF of the spill valve 26 is calculated from the rotational speed NE detected by the rotational speed sensor 40 and the opening timing QANGF of the spill valve 26 previously obtained in S130 described later, and then continues. In S130, the opening timing QANGF of the spill valve 26 is calculated from the rotational speed NE detected by the rotational speed sensor 40 and the injection amount command value QFIN obtained in S110. Finally, in S140, the spill valve 26 is opened and closed by outputting to the drive circuit 38 a drive signal corresponding to the valve closing timing QPANGF and the valve opening timing QANGF of the spill valve 26 obtained in S120 and S130. The process is temporarily terminated.
[0036]
Next, FIG. 3 is a flowchart showing a fuel cutoff valve opening / closing process executed by the ECU 30, that is, a fuel cutoff valve opening / closing process repeatedly executed by the ECU 30 in order to control the fuel cutoff valve 24.
[0037]
In this fuel cutoff valve opening / closing process, first, in S210, it is determined whether or not the ignition switch is in an ON state. If the ignition switch is in the ON state, the process proceeds to S220, where it is determined whether or not a failure of the spill valve 26 has been detected in the process described later. If no failure of the spill valve 26 has been detected. In order to supply fuel from the injection pump 10 to the engine 2, a drive signal for the fuel cutoff valve 24 is output to the drive circuit 38 to open the fuel cutoff valve 24, and then the process is temporarily terminated.
[0038]
On the other hand, if it is determined in S210 that the ignition switch is not in the ON state, or if it is determined in S220 that a failure of the spill valve 26 has been detected, fuel is supplied from the injection pump 10 to the engine 2. There is no need, and particularly when the spill valve 26 is in a closed state, when the fuel shut-off valve 24 is opened and fuel is supplied to the pump chamber 12, a large amount of fuel is supplied to the engine 2 so that the engine 2 Since there is a possibility of overrun and damage to the engine 2, the process proceeds to S 240, after stopping the output of the drive signal of the fuel cutoff valve 24 to the drive circuit 38 and closing the fuel cutoff valve 24, The process is temporarily terminated.
[0039]
As a result, if the ignition switch is ON and no failure of the spill valve 26 is detected, the fuel cutoff valve 24 is held open. When the fuel cutoff valve 24 is held in the open state in this way, the supply flow path 20 of the injection pump 10 is compressed after the pump chamber 12 is compressed by the movement of the plunger 14, as shown in FIG. The plunger 14 communicates with the rotation of the plunger 14 and a slit (not shown) at the tip of the plunger 14. Therefore, the fuel is sucked into the pump chamber 12 as the plunger 14 is subsequently retracted and the pump chamber 12 expands. When the pump chamber 12 is expanded to the maximum volume, the supply flow path 20 is blocked by the rotation of the plunger 14.
[0040]
On the other hand, the valve closing timing QPANGF and the valve opening timing QANGF of the spill valve 26 calculated by the spill valve opening / closing process close the spill valve 26 before the plunger 14 starts to compress the pump chamber 12, as shown in FIG. The spill valve 26 is opened when the amount of fuel pumped to the fuel injection valve 4 (and hence the engine 2) reaches the injection amount command value QFIN by the plunger 14 compressing the pump chamber 12. Is for. Therefore, the fuel injection amount from the injection pump 10 to the engine 2 is controlled to the injection amount command value QFIN by the closing timing QPANGF and the opening timing QANGF of the spill valve 26 controlled by the spill valve opening / closing process. become.
[0041]
Further, in the fuel cutoff valve opening / closing process, if a failure of the spill valve 26 is detected in the process described later, the fuel cutoff valve 24 is closed. In this state, no fuel is supplied to the pump chamber 12 of the injection pump 10, so that the fuel supply from the injection pump 10 to the engine 2 is stopped and the engine 2 is forcibly stopped. In the present embodiment, the spill valve opening / closing process functions as an injection amount control means.
[0042]
FIG. 4 is a flowchart showing a rotation fluctuation abnormality determination process executed in the ECU 30, that is, a rotation fluctuation abnormality determination process for determining a failure of the spill valve 26 from the rotation fluctuation of the injection pump 10 (in other words, the engine 2). .
[0043]
As shown in FIG. 4, in the rotation fluctuation abnormality determination process, first, at S300, a rotation fluctuation reference value DNEBASE is calculated based on the rotation speed NE detected by the rotation speed sensor 40 and the injection amount command value QFIN.
[0044]
The rotation fluctuation reference value DNEBASE calculated in S300 is a reference value for determining a failure of the spill valve 26 from the rotation fluctuation DNE (see FIG. 6A) that occurs every cycle of the engine 2, and is previously tested. This is calculated using a map (QFIN, NE, DNE ternary map) as shown in FIG.
[0045]
A map for calculating the rotation fluctuation reference value as shown in FIG. 6C, which is a basis for calculating the rotation fluctuation reference value DNEBASE, is stored and held in the ECU 30, and constitutes the reference value holding means according to claim 1. .
[0046]
Here, a setting method of map data for calculating the rotation fluctuation reference value stored and held by the reference value holding means will be described below. First, as shown in FIG. 6A, the rotational fluctuation DNE of the injection pump 10 (in other words, the engine 2) is generated in synchronization with the rotation of the engine 2. It can be detected from the change in the pulse interval of the pulse signal output at every predetermined rotation angle. Then, when the spill valve 26 is operating normally, the rotational fluctuation DNE increases according to the injection amount command value QFIN and the rotational speed NE as shown by the solid line in FIG. If the valve breaks down in the closed state, it becomes constant at a high level, as shown by the one-dot chain line in FIG. The rotational fluctuation DNE has a characteristic that it increases as the rotational speed NE increases and the injection amount command value QFIN increases.
[0047]
Then, as indicated by a dotted line in FIG. 6B, a value slightly higher than the normal rotation fluctuation DNE can be set between the normal rotation fluctuation DNE and the rotation fluctuation DNE when the spill valve malfunctions. The basic calculation method is to prepare a map for calculating the rotational fluctuation reference value shown in FIG. 6C in advance and calculate the rotational fluctuation reference value DNEBASE using this map.
[0048]
However, the map for calculating the rotation fluctuation reference value shown in FIG. 6C is that the rotation fluctuation data set in advance is rotation fluctuation data set slightly larger than the machine difference center data, and this data is uniform. Therefore, it is not possible to cope with variations in the difference in the drive transmission system between the injection pumps that vary depending on the engine 2 and changes with time of the engine 2.
[0049]
That is, as shown in FIG. 7 (a), the injection pump 10 (in other words, the engine 2) whose upper limit is the machine difference variation (belt tension, backlash of the gear drive unit) of the drive transmission system between the engine 2 and the injection pump. In, the rotation fluctuation data (solid line) is measured larger than that of the engine 2 at the center of the machine difference variation even during normal injection. The greatly measured rotation fluctuation data exceeds the preset rotation fluctuation data, that is, the rotation fluctuation reference value DNEBASE (one-dot chain line), and the region where the normal range injection is erroneously determined as abnormal (FIG. 7 (b)) may occur. This tendency of erroneous determination increases as the engine 2 changes with time (an increase in variation due to deterioration).
[0050]
Further, as shown in FIG. 7B, in the engine 2 in which the machine difference variation of the drive transmission system between the engine 2 and the injection pump is at the lower limit, the rotation fluctuation data (solid line) compared to the engine 2 in the center of the machine difference variation. Therefore, the rotational fluctuation data (broken line) at the time of abnormal injection due to a spill valve failure is also measured small. As a result, the preset rotation fluctuation reference value DNEBASE (one-dot chain line) exceeds the rotation fluctuation data (broken line) at the time of abnormal injection, and the normal injection and abnormal injection cannot be determined (in FIG. 7 ( A)) may occur.
[0051]
Therefore, as shown in FIG. 7 (c), the rotational fluctuation reference value DNEBASE set in advance is a rotational fluctuation whose upper limit is a variation in the difference between the drive transmission system and the injection pump during normal injection in consideration of these circumstances. It is set slightly larger than the data ((c) in FIG. 7). (D) in FIG. 7 is rotation fluctuation data in which the machine difference variation of the drive transmission system with the injection pump at the time of normal injection is the lower limit.
[0052]
Note that map data (not shown) for calculating the rotational fluctuation reference value stored and held by the reference value holding means is updated by a reference value learning process described later. Then, map data for calculating a rotational fluctuation reference value suitable for each engine is set in accordance with the machine difference in the drive transmission system with the injection pump that varies depending on the engine 2 and the temporal change of the engine 2. FIG. 7D shows the result of calculating the rotation fluctuation reference value DNEBASE ((e) in FIG. 7) in S300 using map data for calculating the rotation fluctuation reference value suitable for each engine. .
[0053]
When the rotation fluctuation reference value DNEBASE is thus calculated in S300, the process proceeds to S310. In S310, in the engine 2 in which the engine injection amount command value is large and is difficult to distinguish from the rotation fluctuation data at the time of failure when the spill valve 26 is closed, the rotation fluctuation abnormality determination executed by the ECU 30 is performed. It is effective to set the conditions of the injection amount range to be performed. That is, the determination execution upper limit injection amount QFINMAX is determined, and when it is equal to or larger than the determined injection amount QFINMAX, the rotation fluctuation abnormality determination is not performed. Then, only in the case where it is equal to or less than the determined injection amount QFINMAX, the process proceeds to S320 in order to perform the rotational fluctuation abnormality determination in the following steps.
[0054]
In S320, it is determined whether or not the rotational fluctuation DNE calculated based on the detection signal from the rotational speed sensor 40 exceeds the rotational fluctuation reference value DNEBASE. When the rotational fluctuation DNE is equal to or smaller than the rotational fluctuation reference value DNEBASE, it is determined (stored) that the rotational fluctuation (in other words, the spill valve 26) is normal in S340, and a reference value, which will be described later, in S350. A learning process is executed, and the process is temporarily terminated. Conversely, when the rotational fluctuation DNE exceeds the rotational fluctuation reference value DNEBASE, it is determined (stored) that the rotational fluctuation (in other words, the spill valve 26) is abnormal in S330, and the process is temporarily terminated. . Note that the processing of S320 to S340 functions as a failure determination means.
[0055]
Next, FIG. 5 shows a reference value learning process executed in the ECU 30, that is, a rotational fluctuation reference value stored and held by the reference value holding means so as to correspond to a machine difference variation of the drive transmission system with the injection pump that differs depending on the engine 2. It is a flowchart which shows the process which updates the map data for calculation (ternary map of QFIN, NE, and DNE).
[0056]
As shown in FIG. 5, S400 of the reference value learning process is a process for determining whether a condition for starting learning is satisfied. In the present embodiment, for example, it is determined whether the injection amount command value QFIN is equal to or less than zero, such as a fuel cut during deceleration, that is, whether there is no injection condition. When QFIN is equal to or less than zero, the process proceeds to S410.
[0057]
In S410, the rotational speed NE is detected from the signal from the rotational speed sensor 40, rotational fluctuation data DNE corresponding to the detected rotational speed NE is measured, and both data are temporarily stored. The measurement data range and data pitch of the rotational speed NE to be measured here are the rotation variation data stored in advance and read out in the next step (S420), and the same measurement data range and data pitch. In other words, when the conditions coincide with the rotational speed NE stored and held in advance, data acquisition under those conditions is performed as described above.
[0058]
Next, in S420, using the map (not shown) consisting of the rotational speed NE and the rotational fluctuation data DNE corresponding to the rotational speed NE that are created in advance by experiments and stored in the ROM, the same operating conditions as the data acquired in S410 are obtained. (Same rotation speed NE) data is calculated (read), and after the data is temporarily stored, the process proceeds to S430 in the next step. The map data read in this step is rotation fluctuation data of the median difference between the injection pumps and data under no-injection conditions.
[0059]
The map data read in S420 may be rotation fluctuation data deviating from the median value in addition to the above-described machine fluctuation median rotation fluctuation data. In this case, the reproducibility of the rotation fluctuation data is lower than that of the rotation fluctuation data of the machine difference median value, but it is practical.
[0060]
In S430, the difference between both data temporarily stored in S410 and S420 is calculated, and this data is temporarily stored. That is, the difference between the rotation fluctuation data DNE of S410 and the rotation fluctuation data DNE of S420 at the same rotation speed NE of both data of S410 and S420 is calculated.
[0061]
The processing at S430 is shown in FIG. FIG. 8 is an explanatory diagram for explaining the operation of the reference value learning process. (A) in FIG. 8B is a rotation fluctuation data point stored and held in advance read in S420, and is rotation fluctuation data when the rotation speed NE = 2000 rpm and QFIN = 0. 8B is the rotation fluctuation data DNE measured in S410, and the difference between the rotation fluctuation data is Δne.
[0062]
Steps S410 to S430 described above constitute the corrected rotation fluctuation detection means according to the first aspect. And the correction | amendment rotation fluctuation | variation detection means was made into the rotation fluctuation data DNE and DNEC corresponding to the rotation speed NE on no injection conditions. This non-injection condition is a condition under which reproducible rotation fluctuation data can be obtained in measuring rotation fluctuation data.
[0063]
In addition to the above-described no-injection condition, the corrected rotation fluctuation detecting means calculates the rotation speed change rate from, for example, the rotation speed sensor 40, and maintains the stable rotation speed when the rotation speed change rate is below a specified level. It may be executed under certain conditions. By using this rotational speed change rate as a precondition for execution of the corrected rotational fluctuation detecting means, it is possible to obtain reproducible rotational fluctuation data when measuring the rotational fluctuation data.
[0064]
In addition to the above-described no-injection condition, the corrected rotation fluctuation detecting means detects, for example, the opening degree of the accelerator sensor 42 and calculates the change rate of the detected accelerator opening degree. And it may be made to execute on the conditions which maintain the stable accelerator opening, when the accelerator opening change rate is below a regulation level. By using this accelerator opening change rate as a precondition for execution of the corrected rotation fluctuation detecting means, it is possible to obtain reproducible rotation fluctuation data when measuring the rotation fluctuation data.
[0065]
In S400, when the injection amount command value QFIN is equal to or greater than zero, that is, when there is an injection condition, the reference value learning process is stopped and the process is temporarily ended.
[0066]
When the difference DNEADD between both the data in S410 and S420 is calculated in S430, the process proceeds to S440 and subsequent steps. In the processes of S440, S450, and S480, the rotational fluctuation reference value DNEBASE based on the rotational speed NE and the injection amount command value QFIN stored and held by the reference value holding means is used as the injection amount command value QFIN in steps S460 to S480 described later. It is a repetition condition for updating over the entire range.
[0067]
That is, in S440, the rewritable temporary storage area QFINM (injection amount) is used to read the rotation fluctuation reference value DNEBASE stored in the map data for calculating the rotation fluctuation reference value into the rewritable temporary storage area. Each map point for storing rotation fluctuation data corresponding to the command value QFIN is designated. Therefore, in S400, the map point KQFINMF of the injection amount command value QFIN lower limit is designated. Next, in S450, S460 to S480 are repeatedly executed according to the injection amount command value QFIN pitch until each map point QFIM described above reaches the injection amount command value QFIN upper limit map point KQMMAX.
[0068]
In S460 during this repetitive process, the one-point data DNEBS in the rotation fluctuation reference value DNEBASE stored and held in the map data for calculating the rotation fluctuation reference value is read out and stored in each map point QFINM for each designated rotation speed NE. . The read data is an initial value DNEBS, which is the first data according to claim 1.
[0069]
In S470, instead of the data DNEBS (first data) stored in S460, the updated rotation fluctuation reference value DNEBASE (second data) which is data obtained by adding the difference DNEADD obtained in S430 to the data DNEBS described above. Data).
[0070]
Next, in S480, the map pitch KQFINMP of the injection amount command value QFIN is added to each map point QFINM for each rotation speed NE in order to shift to each map point QFIM for each designated rotation speed NE, and the above-mentioned. S450 to S470 are repeated.
[0071]
The steps from S450 to S470 described above are shown in FIG. FIG. 8A shows the rotation fluctuation reference value DNEBASE stored and held in the map data for calculating the rotation fluctuation reference value, and shows a state in which data is read out to a rewritable temporary storage area in FIG. 8B. Shown in (C). And (D) in FIG.8 (b) shows the state which reflected the difference ((DELTA) ne) of rotation fluctuation data uniformly.
[0072]
Thus, the updated rotation fluctuation reference value DNEBASE, which uniformly reflects the difference (Δne) in the rotation fluctuation data for correcting the machine difference variation corresponding to the rotation speed of the internal combustion engine, is the second variation according to claim 1. This is data, and can be second data that is rotational fluctuation difference data in which the machine difference is accurately corrected over the entire injection amount command value. The processing from S440 to S480 described above functions as an update reference value holding unit.
[0073]
Further, by repeatedly executing the reference value learning process from S400 to S480 described above, the rotation fluctuation reference value DNEBASE is updated to the second data (rotation fluctuation reference value DNEBASE) that matches the latest state of the internal combustion engine. be able to. Then, using the updated rotation fluctuation reference value DNEBASE, the rotation fluctuation abnormality determination process described above is performed. The second data updated in this way can be data that has absorbed the change over time of the internal combustion engine, in other words, is not affected by the change over time.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a configuration of a fuel injection device for an internal combustion engine according to the present invention.
FIG. 2 is a flowchart showing a spill valve opening / closing process executed in the ECU.
FIG. 3 is a flowchart showing a fuel cutoff valve opening / closing process executed in the ECU.
FIG. 4 is a flowchart showing rotation fluctuation abnormality determination processing executed in the ECU.
FIG. 5 is a flowchart showing a reference value learning process executed in the ECU.
FIG. 6 is an explanatory diagram for explaining the operation of rotation fluctuation abnormality determination processing;
FIG. 7 is an explanatory diagram for explaining the operation of rotation fluctuation abnormality determination processing;
FIG. 8 is an explanatory diagram illustrating an operation of a reference value learning process.
FIG. 9 is a timing chart showing opening / closing timings of the spill valve and the supply flow path.
[Explanation of symbols]
10 Injection pump
12 Pump room
14 Plunger
20 Supply channel
24 Fuel shut-off valve
26 Spill valve
30 ECU
40 RPM sensor
42 Accelerator sensor

Claims (5)

A pump chamber that expands and contracts by reciprocating movement of the plunger; a supply passage that supplies fuel to the pump chamber; and a spill valve that releases the fuel from the pump chamber, and injects pressurized fuel in the pump chamber into the internal combustion engine. An injection pump to supply;
An injection amount control means for calculating an injection amount command value based on operating conditions including the rotational speed of the internal combustion engine and an accelerator opening, and for controlling the opening and closing of the spill valve according to the injection amount command value;
The rotation fluctuation of the injection pump is detected, and the detected value is more than the first data which is rotation fluctuation data at the time of abnormality of the injection pump corresponding to the preset rotation speed of the internal combustion engine and the injection amount command value. In a fuel injection device for an internal combustion engine comprising failure determination means for determining a failure in a closed state of the spill valve when larger,
The failure determination means includes
Reference value holding means for storing and holding the first data;
Correction rotation fluctuation detection means for calculating correction rotation fluctuation data from rotation fluctuation data during a specific operation of the injection pump and rotation fluctuation data of the injection pump stored in advance under the same operation conditions as this data;
Reference value learning means for updating the first data using the corrected rotation fluctuation data detected by the corrected rotation fluctuation detecting means, and storing and holding the updated second data in an update reference value holding means; Prepared,
Instead of the first data, the abnormality of rotation fluctuation of the injection pump is detected based on the second data, and it is determined that the spill valve is in a closed state ,
The correction rotation fluctuation detecting means stores, as the correction rotation fluctuation data, rotation fluctuation data corresponding to the rotation speed of the internal combustion engine measured during the specific operation, and pre-stores the rotation fluctuation data under the same operating conditions as the rotation fluctuation data. Calculating rotation fluctuation difference data that is a difference from rotation fluctuation data corresponding to the rotation speed of the internal combustion engine,
The rotation fluctuation data constituting the first data changes according to the magnitude of the injection amount command value, and the update reference value holding means is the rotation of the internal combustion engine measured during the specific operation. The rotation fluctuation difference data is uniformly reflected on all the rotation fluctuation data at the time of abnormality of the injection pump with respect to the entire injection amount command value, and the reflected data is used as the second data. A fuel injection device for an internal combustion engine characterized by storing and holding the memory .   2. The fuel injection device for an internal combustion engine according to claim 1, wherein the rotation fluctuation data of the injection pump stored and held in advance is rotation fluctuation data of a median difference between the injection pumps. During the specific operation , the injection pump is not in injection , the rate of change in the rotational speed of the internal combustion engine is below a specified level, or the rate of change in the accelerator opening of the vehicle is below a specified level. The fuel injection device for an internal combustion engine according to claim 1 or 2 . When the failure determination means determines a failure in the closed state of the spill valve using the second data stored and held by the update reference value holding means,
When the rotation fluctuation of the injection pump is detected and the detected data is equal to or more than the second data, it is determined that the spill valve is in a closed state,
4. The fuel injection device for an internal combustion engine according to claim 1 , wherein, when the detected data is not equal to or greater than the second data, the reference value learning unit is executed . 5. The failure determination means determines the failure in the closed state of the spill valve by using the latest second data stored and held by the updated reference value holding means, wherein the reference value learning means is repeatedly executed. The fuel injection device for an internal combustion engine according to claim 4 .

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