Method for initializing high-pressure pump correction learning values ​​and common rail fuel injection control device

Abstract

The system determines whether or not to initialize the high-pressure pump correction learning values, and enables automatic initialization if necessary. [Solution] A method for initializing a high-pressure pump correction learning value, comprising: periodically acquiring a rail pressure deviation, which is the difference between the indicated rail pressure and the actual rail pressure; calculating an integral rail pressure deviation value, which is the sum of the periodically acquired rail pressure deviations; temporarily invalidating the high-pressure pump correction learning value stored in an EEPROM provided in the electronic control unit if this integral rail pressure deviation value is outside a predetermined detection range; acquiring a new high-pressure pump correction learning value through learning; and initializing the high-pressure pump correction learning value in the EEPROM if the acquired high-pressure pump correction learning value does not meet predetermined tolerance conditions.

Description

Technical Field

[0001] The present invention relates to a method for initializing a learning value for correcting the discharge amount of a high-pressure pump in a common rail type fuel injection control device, and to the common rail type fuel injection control device.

Background Art

[0002] In a common rail type fuel injection control device, a deviation may occur between the target discharge amount and the actual discharge amount due to manufacturing variations of the high-pressure pump, aging changes, and the like. Conventionally, for example, the following method has been known as a method for correcting the deviation. For example, a method of obtaining a learning value of a correction amount (hereinafter referred to as "high-pressure pump correction learning value") by learning processing or the like and performing correction based on the obtained high-pressure pump correction learning value is known (for example, see Patent Document 1).

[0003] The above-mentioned high-pressure pump correction learning value is often stored in a non-volatile memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory). The high-pressure pump correction learning value stored in the EEPROM is for correcting the discharge amount of the high-pressure pump when the learning process is executed. Therefore, the high-pressure pump correction learning value already stored in the EEPROM when the high-pressure pump is replaced is not necessarily suitable for correcting the discharge amount of the high-pressure pump after replacement. Therefore, it is necessary to make the high-pressure pump correction learning value suitable for correcting the discharge amount of the high-pressure pump after replacement. Optimization of the high-pressure pump correction learning value is often performed at a maintenance factory or the like as part of the high-pressure pump replacement work. At that time, the data of the EEPROM is reset by a service tool or the like, that is, the high-pressure pump correction learning value is initialized.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] However, since the preparation and initiation of the equipment required to initialize the high-pressure pump correction learning value in the EEPROM as described above are left to the vehicle maintenance worker, there is a possibility, albeit a very slight one, that the worker might forget about the initialization process itself, which cannot be ruled out. If the vehicle is started without initializing the high-pressure pump correction learning values, malfunctions such as starting problems may occur.

[0006] The present invention has been made in view of the above circumstances, and provides a method for initializing high-pressure pump correction learning values ​​and a common rail fuel injection control device that enables automatic initialization when initialization of high-pressure pump correction learning values ​​is required when the vehicle starts up. [Means for solving the problem]

[0007] To achieve the above objectives of the present invention, the method for initializing high-pressure pump correction learning values ​​according to the present invention is: A method for initializing a high-pressure pump correction learning value in a non-volatile memory by a common rail fuel injection control device, which stores a high-pressure pump correction learning value, which is a learned value of the correction amount, in order to correct the discharge amount of the high-pressure pump, and performs correction control of the discharge amount of the high-pressure pump based on the high-pressure pump correction learning value, The system is configured to periodically acquire the rail pressure deviation, which is the difference between the indicated rail pressure and the actual rail pressure, calculate the rail pressure deviation integral value, which is the sum of the rail pressure deviations acquired periodically, and if the rail pressure deviation integral value is outside a predetermined detection range, temporarily invalidate the high-pressure pump correction learning value stored in the non-volatile memory, acquire a new high-pressure pump correction learning value through learning, and initialize the high-pressure pump correction learning value in the non-volatile memory if the newly acquired high-pressure pump correction learning value does not meet predetermined tolerance conditions. Furthermore, in order to achieve the above-mentioned objectives of the present invention, the common rail fuel injection control device according to the present invention is: The system includes an electronic control unit that learns a correction amount for correcting the discharge rate of a high-pressure pump that pumps fuel from a fuel tank to a common rail, and performs correction control of the discharge rate of the high-pressure pump based on the high-pressure pump correction learning value obtained through learning, and a non-volatile memory that stores the high-pressure pump correction learning value. The aforementioned electronic control unit is The system periodically acquires the rail pressure deviation, which is the difference between the indicated rail pressure and the actual rail pressure. It calculates the rail pressure deviation integral value, which is the sum of the rail pressure deviations acquired periodically. If the rail pressure deviation integral value is outside a predetermined detection range, the high-pressure pump correction learning value stored in the non-volatile memory is temporarily invalidated. A new high-pressure pump correction learning value is acquired through new learning. If the acquired new high-pressure pump correction learning value does not meet predetermined tolerance conditions, the high-pressure pump correction learning value in the non-volatile memory is initialized. [Effects of the Invention]

[0008] According to the present invention, it becomes possible to determine whether or not the high-pressure pump correction learning value needs to be initialized, and if initialization is necessary, the initialization is performed. Therefore, it is no longer necessary to leave the initialization of the high-pressure pump correction learning value after the high-pressure pump is replaced to the vehicle user. Consequently, even if the user does not perform any initialization processing, initialization will be performed if the predetermined tolerance conditions are not met. This avoids starting failures caused by correcting the discharge amount of the high-pressure pump using an inappropriate high-pressure pump correction learning value, and provides a highly reliable common rail fuel injection control device. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an example configuration of a common rail fuel injection control device according to an embodiment of the present invention. [Figure 2]This flowchart shows the specific processing procedure for the first process in the initialization process of the high-pressure pump correction learning value according to an embodiment of the present invention. [Figure 3] This flowchart shows the specific processing procedure for the second process in the initialization process of the high-pressure pump correction learning value according to an embodiment of the present invention. [Figure 4] This flowchart shows the specific processing procedure for the third process in the initialization process of the high-pressure pump correction learning value according to an embodiment of the present invention. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described with reference to Figures 1 to 5. The components, arrangements, etc., described below are not intended to limit the present invention and can be modified in various ways within the scope of the spirit of the present invention. First, an example configuration of a common rail fuel injection control device to which the high-pressure pump correction learning value initialization method in the embodiment of the present invention is applied will be described with reference to Figure 1. The common rail fuel injection control device according to this embodiment includes a high-pressure pump device 50 for pumping high-pressure fuel, a common rail 1 for storing the high-pressure fuel pumped by the high-pressure pump device 50, a plurality of fuel injection valves 2-1 to 2-n for injecting the high-pressure fuel supplied from the common rail 1 into the cylinders of a diesel engine (hereinafter referred to as "engine") 3, and an electronic control unit (indicated as "ECU" in Figure 1) 4 that performs fuel injection control and initialization processing of high-pressure pump correction learning values, which will be described later.

[0011] The high-pressure pump system 50 includes a supply pump 5, a flow control valve 6, and a high-pressure pump 7. Fuel in the fuel tank 9 is pumped up by the supply pump 5 and supplied to the high-pressure pump 7 via the flow control valve 6. Here, the flow control valve 6 is, for example, an electromagnetic proportional control valve, or includes an electromagnetic proportional control valve. The amount of current supplied to the flow control valve 6 is controlled by the electronic control unit 4, thereby adjusting the flow rate of fuel to the high-pressure pump 7, in other words, the discharge amount of the high-pressure pump 7.

[0012] A return valve 8 is provided between the output side of the supply pump 5 and the fuel tank 9. This allows excess fuel from the output side of the supply pump 5 to be returned to the fuel tank 9. Fuel injectors 2-1 to 2-n are provided for each cylinder of the diesel engine 3, and high-pressure fuel is supplied to each from the common rail 1, with fuel injection controlled by the electronic control unit 4.

[0013] The electronic control unit 4 includes, for example, a microcomputer (not shown) and memory elements such as RAM (Random Access Memory) or ROM (Read Only Memory) (not shown). The electronic control unit 4 also includes a drive circuit (not shown) for driving the fuel injection valves 2-1 to 2-n and a power supply circuit (not shown) for supplying power to the flow control valve 6. The electronic control unit 4 receives the detection signal from the pressure sensor 11, which detects the pressure of the common rail 1. The electronic control unit 4 also receives input from one or more sensors (not shown), including engine speed, accelerator opening, and fuel temperature. The electronic control unit 4 performs various control processes based on the detection results obtained from the various sensors.

[0014] In this embodiment of the present invention, the common rail fuel injection control device corrects the discrepancy between the target discharge amount of the high-pressure pump 7 and the actual discharge amount based on a learned value obtained from the learning process. In the following, this learning process may also be referred to as high-pressure pump correction amount learning. In detail, high-pressure pump correction amount learning is learning to obtain a correction amount to correct the discrepancy between the target discharge rate and the actual discharge rate of the high-pressure pump 7. In the following, the learned value obtained through high-pressure pump correction amount learning may also be referred to as the high-pressure pump correction learning value. This high-pressure pump correction learning value is stored, for example, in an EEPROM (Electrically Erasable Programmable Read-Only Memory: non-volatile memory) not shown in the electronic control unit 4.

[0015] The electronic control unit 4 according to an embodiment of the present invention initializes the high-pressure pump correction learning value stored in the EEPROM as needed. In the initialization process of the high-pressure pump correction learning value, based on the fluctuation of the rail pressure, it is determined whether it is necessary to initialize the high-pressure pump correction learning value stored in the EEPROM. When it is determined that the initialization of the high-pressure pump correction learning value is necessary, the initialization of the high-pressure pump correction learning value stored in the EPROM is performed. On the other hand, as will be described later, when it is in a suspicious state where it cannot be determined that the initialization of the high-pressure pump correction learning value is necessary based on the fluctuation of the rail pressure, the rail pressure control based on the high-pressure pump correction learning value is at least temporarily invalidated. After that, when it is determined that the high-pressure pump correction learning value is normal, that is, when it can be determined that the initialization of the high-pressure pump correction learning value is not necessary, the above invalidation is released, and the rail pressure control using the high-pressure pump correction learning value can be continued.

[0016] Hereinafter, the initialization process of the high-pressure pump correction learning value according to the embodiment will be described with reference to FIGS. 2 to 4. Note that FIG. 2 illustrates a flowchart of the first process in the initialization process of the high-pressure pump correction learning value, FIG. 3 illustrates a flowchart of the second process in the initialization process of the high-pressure pump correction learning value, and FIG. 4 illustrates a flowchart of the third process in the initialization process of the high-pressure pump correction learning value. Note that at least the processes after step S240 shown in FIG. 3 are executed after the detection threshold value described later is obtained in step S180 of the first process shown in FIG. 2, but the rest may be executed in parallel with the first process, may be executed after the end of the first process, or may be executed before the end of the first process. After the engine 3 is started, the electronic control unit 4 determines whether the learning of the high-pressure pump correction amount has been completed in step S110, that is, whether the acquisition of the high-pressure pump correction learning value has been completed.

[0017] Furthermore, information on whether or not high-pressure pump correction amount learning is complete may be required in other control processes as well. In this embodiment, a flag (hereinafter referred to as the "learning completion identification flag" for convenience of explanation) is set to identify whether or not high-pressure pump correction amount learning is complete. More specifically, the learning completion identification flag is set to "1" if high-pressure pump correction amount learning is complete, and to "0" if it is not complete. In step S110, the electronic control unit 4 determines whether or not high-pressure pump correction amount learning is complete based on the learning completion identification flag.

[0018] If the high-pressure pump correction amount learning is complete (step S110: YES), the electronic control unit 4 moves the process to step S120. On the other hand, if the high-pressure pump correction amount learning is not complete (step S110: NO), the electronic control unit 4 terminates the first process.

[0019] In step S120, the electronic control unit 4 determines whether or not the engine 3 is in a starting state (starting mode). Here, the starting mode refers to the operating state from the start of cranking until the engine speed reaches idle speed. In this embodiment, a flag or the like indicating the operating state (control state) of engine 3 is set. In step S120, the electronic control unit 4 can determine whether or not it is in the starting mode based on the flag or the like indicating the operating state (control state) of engine 3. If engine 3 is in a running state (step S120: YES), the electronic control unit 4 proceeds to step S130. On the other hand, if engine 3 is not in a running state (step S120: NO), the electronic control unit 4 terminates the first process.

[0020] In step S130, the electronic control unit 4 determines whether rail pressure control is performed using closed-loop control. Here, rail pressure control is performed by either closed-loop control or open-loop control, which is selected based on fluctuations in rail pressure, etc.

[0021] In this situation, closed-loop control is often performed when the rail pressure is normal. Furthermore, the determination of whether or not closed-loop control is being performed may be based on a flag or similar, similar to the determination of the completion of high-pressure pump correction amount learning described above.

[0022] If rail pressure control is performed by closed-loop control (step S130: YES), the electronic control unit 4 moves the process to step S140. On the other hand, if rail pressure control is not performed by closed-loop control (step S130: NO), the electronic control unit 4 terminates the first process.

[0023] In step S140, the electronic control unit 4 performs the following calculation of the rail pressure deviation integral value. First, the rail pressure deviation integral value P_sum is the integral value of the rail pressure deviation Rail_pDvi, which is the difference between the actual rail pressure and the indicated rail pressure. Here, the actual rail pressure is the actual rail pressure detected by the pressure sensor 11, and the instructed rail pressure is the target rail pressure obtained in the rail pressure control process based on the operating status of the engine 3, etc.

[0024] In the embodiment of the present invention, the calculation of the integrated value of the rail pressure deviation refers to the cumulative calculation of the sum of the rail pressure deviations Rail_pDvi obtained from immediately after the start of the engine 3 and the switch of the rail pressure control to closed-loop control up to the present time.

[0025] In step S150, the electronic control unit 4 determines whether the start mode termination conditions have been met. The start mode termination conditions include at least one of the following: a first condition that the engine 3 has exited the start mode, and a second condition that a predetermined first time has elapsed since it was determined that rail pressure control is being performed by closed-loop control. If the startup mode termination conditions include both the first and second conditions described above, then "when the startup mode termination conditions are met" means when at least one of the first or second conditions is met, and "when the startup mode termination conditions are not met" means when neither the first nor the second condition is met.

[0026] If the conditions for ending the start mode are met (step S150: YES), the electronic control unit 4 proceeds to step S160. On the other hand, if the conditions for ending the start mode are not met (step S150: NO), the electronic control unit 4 returns to step S140. In the embodiment of the present invention, the processing in steps S140 to S150 is performed at a sampling period of Rail pressure deviation Rail_pDvi, for example, a period of 10 msec. The first time is, for example, 1 sec. If the start mode termination condition includes only the second condition, and the sampling frequency of various data in the electronic control unit 4 is 100 Hz, and the first time is 1 sec, then in steps S140 to S150, 100 Rail pressure deviations Rail_pDvi are acquired during that 1 sec, and their sum is calculated in step S140 as the rail pressure deviation integral value P_sum. If it is determined in step S150 that the start mode termination condition is not met, in step S140 the electronic control unit 4 adds the newly obtained Rail pressure deviation Rail_pDvi to the sum calculated in the previous step S140, and the value obtained by adding is the new sum.

[0027] In step S160, the electronic control unit 4 stores the rail pressure deviation integral value P_sum calculated in step S140 in the EEPROM within the electronic control unit 4.

[0028] In this embodiment, the EEPROM of the electronic control unit 4 stores a maximum number of rail pressure deviation integral values ​​P_sum, which is a predetermined upper limit. If more rail pressure deviation integral values ​​P_sum than this maximum number have been acquired up to the present time, the oldest rail pressure deviation integral value P_sum in the time series among the already stored rail pressure deviation integral values ​​P_sum will be overwritten by the newly acquired rail pressure deviation integral value P_sum.

[0029] When step S160 is executed, if the number of rail pressure deviation integral values ​​P_sum stored in the EEPROM of the electronic control unit 4 is less than the maximum number of values ​​that can be stored, the rail pressure deviation integral values ​​P_sum obtained by the process in step S140 are newly written and stored. On the other hand, when step S160 is executed, if the EEPROM already contains the maximum number of rail pressure deviation integral values ​​P_sum, the oldest rail pressure deviation integral value P_sum in the time series among the stored rail pressure deviation integral values ​​P_sum will be overwritten by the rail pressure deviation integral value P_sum obtained by the most recent step S140. The maximum number of values ​​that can be stored is, for example, 10.

[0030] The maximum number of items to be stored may be determined for each vehicle or it may be determined uniformly. In this embodiment, considering that the appropriate value may differ for each individual vehicle, the maximum number of items to be stored is determined for each vehicle through adaptation work during vehicle development, etc. Here, the EEPROM that stores the rail pressure deviation integral value P_sum may be the same as the one that stores the high-pressure pump correction learning value, or it may be a separate one. If the rail pressure deviation integral value P_sum and the high-pressure pump correction learning value are stored in the same EEPROM, then naturally, each of the rail pressure deviation integral value P_sum and the high-pressure pump correction learning value will be stored in a separately allocated memory area.

[0031] In step S170, the electronic control unit 4 determines whether the maximum number of rail pressure deviation integral values ​​P_sum are stored in the EEPROM. If the maximum number of rail pressure deviation integral values ​​P_sum are stored (step S170: YES), the electronic control unit 4 moves the process to step S180. On the other hand, if the maximum number of rail pressure deviation integral values ​​P_sum are not stored in the EEPROM (step S170: NO), the electronic control unit 4 terminates the first process.

[0032] In step S180, the electronic control unit 4 calculates a detection threshold. The details of the detection threshold calculation process are described below. First, the electronic control unit 4 calculates the average value μ and standard deviation s of the maximum number of rail pressure deviation integral values ​​P_sum stored in the EEPROM. Then, the electronic control unit 4 sets μ±3s as a detection threshold for determining whether the rail pressure control, described later, is abnormal or not. More specifically, a detection range is set with μ+3s as the upper limit and μ-3s as the lower limit of the detection threshold. In the above example, the coefficient 3 obtained by multiplying the standard deviation s is just one example and is not limited to this; it may be appropriately selected according to the characteristics of the vehicle, etc. After step S180 is completed, the electronic control unit 4 terminates the first process.

[0033] Next, the second process will be explained with reference to the flowchart shown in Figure 4. After the engine 3 is started, the electronic control unit 4 determines in step S210 whether or not the engine 3 is in a starting state (starting mode). If engine 3 is in a running state (step S210: YES), the electronic control unit 4 proceeds to step S220. On the other hand, if engine 3 is not in a running state (step S210: NO), the electronic control unit 4 terminates the second process.

[0034] In step S220, the electronic control unit 4 determines whether or not rail pressure control is performed using closed-loop control. If rail pressure control is performed by closed-loop control (step S220: YES), the electronic control unit 4 proceeds to step S230. On the other hand, if rail pressure control is not performed by closed-loop control (step S220: NO), the electronic control unit 4 moves to step S260.

[0035] In step S230, the electronic control unit 4 calculates the integral value of the rail pressure deviation. That is, the electronic control unit 4 calculates the cumulative sum of the rail pressure deviations Rail_pDvi obtained from immediately after the rail pressure control switched to closed-loop control after the engine 3 was started until the present. In step S240, the electronic control unit 4 determines whether the integral value of the rail pressure deviation P_sum calculated in step S230 is within the detection range, that is, whether it is greater than or equal to the lower limit μ-3s and less than or equal to the upper limit μ+3s. If the rail pressure deviation integral value P_sum is greater than or equal to the lower limit μ-3s and less than or equal to the upper limit μ+3s (step S240: YES), the electronic control unit 4 moves the process to step S250. On the other hand, if the rail pressure deviation integral value P_sum is less than the lower limit μ-3s or greater than the upper limit μ+3s (step S240: NO), the electronic control unit 4 moves the process to step S280.

[0036] In step S250, the electronic control unit 4 determines whether or not the start mode termination condition has been met. If the conditions for ending the start mode are met (step S250: YES), the electronic control unit 4 proceeds to step S160. On the other hand, if the conditions for ending the start mode are not met (step S250: NO), the electronic control unit 4 returns to step S230.

[0037] If it is determined in step S220 that rail pressure control is not being performed by closed-loop control (step S220: NO), that is, if it is determined that rail pressure control is being performed by open-loop control, then in step S260 the electronic control unit 4 determines whether the rail pressure control has continued in the open-loop control state for a predetermined rail pressure determination time or longer. In this context, if open-loop control continues for longer than the rail pressure determination time in the startup mode, it means that the rail pressure in the startup mode has not risen appropriately. The rail pressure determination time is, for example, 1 second. The rail pressure determination time may be set uniformly for multiple vehicles, or it may be set for each vehicle according to the vehicle's specifications, etc.

[0038] If the open-loop control continues for longer than the rail pressure determination time (step S260: YES), the electronic control unit 4 proceeds to step S270. On the other hand, if the open-loop control has not continued for longer than the rail pressure determination time (step S260: NO), the electronic control unit 4 returns to step S220. The reason why, if the open-loop control in step S260 has not continued for longer than the rail pressure determination time, the process returns to step S220 and it is determined again whether the rail pressure control is by closed-loop control is as follows: If the open-loop control from step S220 to step S260 is due to a temporary or sudden reason, the rail pressure may be able to return to a normal state. The process returns from step S260 to S220 to determine whether the rail pressure has returned to a normal state.

[0039] In step S270, the electronic control unit 4 determines whether or not correction control of the discharge amount of the high-pressure pump 7 is being performed based on a negative high-pressure pump correction learning value. If the corrective control of the discharge volume of the high-pressure pump 7 is being performed based on a negative high-pressure pump correction learning value (step S270: YES), the electronic control unit 4 moves the process to step S280.

[0040] On the other hand, if the correction control of the discharge volume of the high-pressure pump 7 is not performed based on a negative high-pressure pump correction learning value (step S270: NO), the electronic control unit 4 terminates the second process, assuming that the rail pressure control by open-loop control is not due to a negative high-pressure pump correction learning value.

[0041] In step S280, the electronic control unit 4 temporarily disables the high-pressure pump correction learning value. Therefore, in the correction control of the discharge volume of the high-pressure pump 7, which is performed separately, the correction amount for the target discharge volume is temporarily set to an initial value such as zero.

[0042] Next, the specific details of the third process will be explained with reference to Figure 4. The third process may be executed after all or part of the first process, or after all or part of the second process, or it may be executed in parallel with the first or second process. After the engine 3 is started, the electronic control unit 4 determines in step S310 whether or not the vehicle is in an idle state. If the vehicle is in an idle state (step S310: YES), the electronic control unit 4 proceeds to step S320. On the other hand, if the vehicle is not in an idle state (step S310: NO), the electronic control unit 4 terminates the third process.

[0043] In step S320, the electronic control unit 4 acquires a new high-pressure pump correction learning value for the current idle operation state by executing a learning process. Hereafter, the high-pressure pump correction learning value newly acquired in step S320 may also be referred to as the idle-compatible new high-pressure pump correction learning value AMC_idle_new.

[0044] In step S330, the electronic control unit 4 reads the high-pressure pump correction learning value for idle operation from the high-pressure pump correction learning values ​​stored in the EEPROM. The read high-pressure pump correction learning value may also be referred to as the idle-compatible old high-pressure pump correction learning value AMC_idle_old below. The electronic control unit 4 then calculates the difference between the idle-compatible new high-pressure pump correction learning value AMC_idle_new, which was acquired in the most recent step S320, and the idle-compatible old high-pressure pump correction learning value AMC_idle_old (hereinafter referred to as the "learning value difference"). In other words, the difference in learned values ​​is calculated as follows: (Idle-compatible new high-pressure pump correction learned value AMC_idle_new - Idle-compatible old high-pressure pump correction learned value AMC_idle_old).

[0045] In step S340, the electronic control unit 4 determines whether the learning value difference exceeds a predetermined first tolerance. Here, the first tolerance is preferably the tolerance of the learned value obtained by high-pressure pump correction learning. The specific value of the first tolerance varies depending on the specifications of the high-pressure pump 7, and is set based on test results, simulation results, etc., but for example, ±1000 mm 3 It will be set to approximately / s.

[0046] If the difference in learned values ​​exceeds the first tolerance (step S340: YES), the electronic control unit 4 assumes that the characteristics of the high-pressure pump 7 have changed since the most recent start, or in other words, that there is a high probability that the high-pressure pump 7 has been replaced between the most recent start and the current start, and proceeds to step S350. On the other hand, if the difference in learned values ​​does not exceed the first tolerance (step S340: NO), the electronic control unit 4 moves the process to step S360.

[0047] In step S350, the electronic control unit 4 initializes all high-pressure pump correction learning values ​​stored in the EEPROM. After the processing in step S350, the electronic control unit 4 terminates the third process.

[0048] In step S360, the electronic control unit 4 releases the temporary deactivation of the high-pressure pump correction learning value in step S280 and activates the high-pressure pump correction learning value. As a result, the correction control of the high-pressure pump discharge amount is performed as before based on the activated high-pressure pump correction learning value. Furthermore, the correction control of the high-pressure pump discharge rate by enabling the high-pressure pump correction learning value may be performed based on a value obtained by ramp control, which changes over time to the high-pressure pump correction learning value stored in EEPROM, instead of the high-pressure pump correction learning value read from EEPROM. This suppresses the occurrence of sudden rail pressure fluctuations and makes it possible to stabilize rail pressure control. The degree of change by ramp control may be, for example, 100 mm per second. 3 It's around / s, for example.

[0049] After the processing in step S360, the electronic control unit 4 terminates the third process. As described above, the initialization process of the high-pressure pump correction learning value in the embodiment of the present invention involves acquiring a new high-pressure pump correction learning value in a predetermined vehicle operating state, and if the difference between this value and the high-pressure pump correction learning value stored in the EEPROM for a similar vehicle operating state exceeds a first tolerance, the high-pressure pump correction learning value in the EEPROM is initialized. This avoids the execution of inappropriate high-pressure pump discharge volume correction, thereby improving the stability and reliability of rail pressure control. On the other hand, if the rail pressure fluctuation is not significant enough to immediately determine that EEPROM initialization is necessary, the control based on the high-pressure pump correction learning value is temporarily disabled. Then, under predetermined vehicle operating conditions such as idle operation, a new high-pressure pump correction learning value is acquired. If the difference between this new value and the high-pressure pump correction learning value stored in the EEPROM under similar vehicle operating conditions does not exceed the first tolerance, the disablement of the high-pressure pump correction learning value is released. This ensures reliability by avoiding erroneous EEPROM initialization due to temporary instability in rail pressure control. [Industrial applicability]

[0050] This system is applicable to common rail fuel injection control devices where automatic initialization is desired even if the EEPROM's high-pressure pump correction learning value initialization procedure is forgotten during high-pressure pump replacement. [Explanation of symbols]

[0051] 1… Common Rail 3…Engine 4…Electronic control unit 7. High-pressure pump 11…Pressure sensor

Claims

1. A method for initializing a high-pressure pump correction learning value in a non-volatile memory by a common rail fuel injection control device, which stores a high-pressure pump correction learning value, which is a learned value of a correction amount for correcting the discharge amount of a high-pressure pump, in the non-volatile memory, and performs correction control of the discharge amount of the high-pressure pump based on the high-pressure pump correction learning value, The rail pressure deviation, which is the difference between the indicated rail pressure and the actual rail pressure, is acquired periodically. The rail pressure deviation integral value, which is the sum of the rail pressure deviations acquired periodically, is calculated. If the integrated rail pressure deviation value is outside a predetermined detection range, the high-pressure pump correction learning value stored in the non-volatile memory is temporarily disabled. The high-pressure pump correction learning value is newly acquired through learning, A method for initializing a high-pressure pump correction learning value, characterized in that, if the newly acquired high-pressure pump correction learning value does not meet predetermined tolerance conditions, the high-pressure pump correction learning value in the non-volatile memory is initialized.

2. The method for initializing a high-pressure pump correction learning value according to claim 1, characterized in that, in the vehicle's starting mode, rail pressure control by open-loop control continues for a predetermined rail pressure determination time or longer, and if the high-pressure pump correction learning value is a negative value, the high-pressure pump correction learning value is temporarily disabled.

3. The new high-pressure pump correction learning value is acquired during the first engine start after the high-pressure pump correction learning value is temporarily disabled. The aforementioned predetermined permissible conditions are: A method for initializing a high-pressure pump correction learning value according to claim 1 or 2, characterized in that the difference between the new high-pressure pump correction learning value and the high-pressure pump correction learning value during idle operation stored in the non-volatile memory is within a predetermined first tolerance.

4. The method for initializing a high-pressure pump correction learning value according to claim 3, characterized in that, if the difference between the new high-pressure pump correction learning value and the high-pressure pump correction learning value during idle operation stored in the non-volatile memory is within the first tolerance, the temporary deactivation of the high-pressure pump correction learning value in the non-volatile memory is released.

5. The detection range is defined as the interval between the upper limit μ+ks, obtained by adding ks (obtained by multiplying the standard deviation s by a predetermined coefficient k) to the average value μ, and the lower limit μ-ks, obtained by subtracting ks from the average value μ, based on the average value μ and standard deviation s of a plurality of rail pressure deviation integral values. The method for initializing high-pressure pump correction learning values ​​according to claim 4, characterized in that the plurality of rail pressure deviation integral values ​​are obtained by repeatedly integrating the rail pressure deviation each time rail pressure control is performed by closed-loop control when the vehicle starts up.

6. An electronic control unit learns a correction amount to correct the discharge rate of a high-pressure pump that pumps fuel from a fuel tank to a common rail, and performs correction control of the discharge rate of the high-pressure pump based on the high-pressure pump correction learning value, which is the correction amount obtained through learning. A non-volatile memory for storing the high-pressure pump correction learning value, Equipped with, The aforementioned electronic control unit is The rail pressure deviation, which is the difference between the indicated rail pressure and the actual rail pressure, is acquired periodically. The rail pressure deviation integral value, which is the sum of the rail pressure deviations acquired periodically, is calculated. A common rail fuel injection control device characterized in that, when the integrated rail pressure deviation value is outside a predetermined detection range, the high-pressure pump correction learning value stored in the non-volatile memory is temporarily invalidated, a new high-pressure pump correction learning value is obtained through new learning, and if the newly obtained high-pressure pump correction learning value does not meet predetermined tolerance conditions, the high-pressure pump correction learning value in the non-volatile memory is initialized.

7. The aforementioned electronic control unit is The common rail fuel injection control device according to claim 6, characterized in that, in the vehicle's starting mode, if rail pressure control by open-loop control continues for longer than a predetermined rail pressure determination time, and the high-pressure pump correction learning value is a negative value, the high-pressure pump correction learning value is temporarily disabled.

8. The aforementioned electronic control unit is When the engine is started for the first time after the high-pressure pump correction learning value has been temporarily disabled, the new high-pressure pump correction learning value is acquired. The aforementioned predetermined permissible conditions are: The common rail fuel injection control device according to claim 6 or 7, characterized in that the difference between the new high-pressure pump correction learning value and the high-pressure pump correction learning value during idle operation stored in the non-volatile memory is within a predetermined first tolerance.

9. The aforementioned electronic control unit is The common rail fuel injection control device according to claim 8, characterized in that when the new high-pressure pump correction learning value satisfies the predetermined allowable conditions, the temporary deactivation of the high-pressure pump correction learning value in the non-volatile memory is released.

10. The aforementioned detection range is, Based on the average value μ and standard deviation s of multiple rail pressure deviation integral values, the upper limit μ+ks obtained by adding ks (obtained by multiplying the standard deviation s by a predetermined coefficient k) to the average value μ is determined to be between the lower limit μ-ks obtained by subtracting ks from the average value μ. The aforementioned electronic control unit is The common rail fuel injection control device according to claim 9, characterized in that a plurality of integrated rail pressure deviation values ​​are obtained by repeatedly integrating the rail pressure deviation each time rail pressure control is performed by closed-loop control when the vehicle is started.

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