JP2013238181A - Fuel pumping characteristic variation correction method and fuel pumping characteristic variation correction device for high-pressure pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of correcting fuel pumping characteristic variation of a high pressure pump having high versatility and convenience.SOLUTION: When a vehicle is in a warm-up operating condition, a fuel pumping characteristic variation correction device 102 makes acquisition of a rail pressure characteristic prior to the performance of variation correction via an electronic control unit 4 (S200). Based on the rail pressure characteristic obtained, the calculation of a correction factor for variation correction is performed with the fuel pumping characteristic variation correction device 102 (S300). Acquisition of rail pressure characteristic after variation correction has been performed (S400) is carried out via the electronic control unit 4. If the acquired rail pressure characteristic after variation correction has been performed is found to be within the frame of reference and the variation correction is determined to be adequate (S500), then the previously acquired correction factor is to be stored in the electronic control unit 4 as a learning value (S600).

Description

  The present invention relates to a method and apparatus for correcting variation in fuel pumping characteristics of a high-pressure pump used in a common rail fuel injection control apparatus, and more particularly to an apparatus for improving versatility and convenience.

A so-called common rail type fuel injection control device pressurizes fuel by a high pressure pump, pumps it to a common rail which is an accumulator, accumulates the pressure, and supplies the accumulated high pressure fuel to the injector. It is well known that it can inject fuel and is excellent in fuel consumption, emission characteristics, etc., and various improvements in operational characteristics have been proposed and put into practical use.
In such a common rail fuel injection control device, the supply of fuel to the high-pressure pump is adjusted using an electromagnetic metering valve, which usually has a structural variation width. Even with the same energization current, the amount of fuel passing differs individually, and therefore the pumped fuel from the high pressure pump may rise or fall with respect to the target pumped amount.

As a measure for correcting the variation in the pumping amount of the high-pressure pump, for example, a process for correcting the variation in the fuel pumping characteristic of the high-pressure pump is executed for each common rail fuel injection control device. Conceivable.
For example, the standard energization determined from the actual energization current of the metering valve when the engine is in a predetermined stable state, the energization current of the metering valve acquired in advance in the standard device, and the change characteristics of the discharge amount of the high pressure pump There has been proposed a common rail fuel injection control device and the like configured to correct the energization current based on the difference from the current (see, for example, Patent Document 1).

JP 2008-298022 A (page 5-10, FIG. 1 to FIG. 10)

  However, since the electronic control unit that performs the operation control of the common rail fuel injection control apparatus performs the correction process as described above, it imposes a burden on the operation control of the apparatus by the electronic control unit. A high electronic control unit is required, and there is a problem that the price of the apparatus is increased.

  The present invention has been made in view of the above-described circumstances, and provides a fuel pumping characteristic variation correction method and a fuel pumping characteristic variation correction apparatus that reduce the burden on the electronic control unit as much as possible and are versatile and convenient. To do.

In order to achieve the above object of the present invention, the fuel pumping characteristic variation correcting method of the high pressure pump according to the present invention is:
The fuel in the fuel tank is pressurized and pumped to the common rail by the high-pressure pump, enabling high-pressure fuel injection to the engine via the fuel injection valve connected to the common rail, and at least metering to the upstream side of the high-pressure pump A fuel for the high-pressure pump in a common rail fuel injection control device mounted on a vehicle, provided with a valve and configured so that at least the metering valve is driven and controlled by an electronic control unit to control the rail pressure of the common rail. A method for correcting variations in pumping characteristics,
The vehicle is brought into a predetermined driving state from the outside via the electronic control unit,
In such an operating state, the accelerator opening is changed stepwise via the electronic control unit, and the actual rail pressure at each accelerator opening is acquired as the actual rail pressure before correction,
Based on the acquired actual rail pressure before correction and the target rail pressure, the metering valve of the metering valve in a relative relationship between the energizing current of the metering valve stored in the electronic control unit and the discharge amount of the high-pressure pump is stored. Calculate the correction coefficient to correct the energization current,
The electronic control unit performs correction of the energization current of the metering valve using the calculated correction coefficient, and based on the relative relationship between the corrected energization current of the metering valve and the discharge amount of the high-pressure pump. To change the accelerator opening in stages, and obtain the actual rail pressure at each accelerator opening as the corrected actual rail pressure,
It is determined whether or not the change in the corrected actual rail pressure is appropriate. If it is determined that the change in the corrected actual rail pressure is appropriate, the correction coefficient is stored in the electronic control unit, If it is determined that the change in the actual rail pressure after correction is not appropriate, a series of processes after acquisition of the actual rail pressure before correction is performed until it is determined that the change in actual rail pressure after correction is appropriate. Are configured to be repeated in the same manner.
In order to achieve the above object of the present invention, a fuel pumping characteristic variation correcting device according to the present invention comprises:
The fuel in the fuel tank is pressurized and pumped to the common rail by the high-pressure pump, enabling high-pressure fuel injection to the engine via the fuel injection valve connected to the common rail, and at least metering to the upstream side of the high-pressure pump A fuel for the high-pressure pump in a common rail fuel injection control device mounted on a vehicle, provided with a valve and configured so that at least the metering valve is driven and controlled by an electronic control unit to control the rail pressure of the common rail. A fuel pumping characteristic variation correcting device for correcting variations in pumping characteristics,
The fuel pumping characteristic variation correcting device is
Via the electronic control unit, the vehicle is brought into a predetermined driving state,
In such an operating state, the accelerator opening is changed stepwise via the electronic control unit, and the actual rail pressure at each accelerator opening is acquired as the actual rail pressure before correction,
Based on the acquired actual rail pressure before correction and the target rail pressure, the metering valve of the metering valve in a relative relationship between the energizing current of the metering valve stored in the electronic control unit and the discharge amount of the high-pressure pump is stored. Calculate the correction coefficient to correct the energization current,
The electronic control unit performs correction of the energization current of the metering valve using the calculated correction coefficient, and based on the relative relationship between the corrected energization current of the metering valve and the discharge amount of the high-pressure pump. To change the accelerator opening in stages, and obtain the actual rail pressure at each accelerator opening as the corrected actual rail pressure,
It is determined whether or not the change in the corrected actual rail pressure is appropriate. If it is determined that the change in the corrected actual rail pressure is appropriate, the correction coefficient is stored in the electronic control unit, If it is determined that the change in the actual rail pressure after correction is not appropriate, a series of processes after acquisition of the actual rail pressure before correction is performed until it is determined that the change in actual rail pressure after correction is appropriate. Are configured to be repeated in the same manner.

According to the present invention, the variation correction of the fuel pumping characteristic of the high-pressure pump can be performed using an inspection device (service tool) used in vehicle maintenance or a similar device. The electronic control unit that controls the operation of the injection control device does not need to be equipped with a function to correct the variation in the fuel pumping characteristics of the high-pressure pump, and the burden on the electronic control unit can be reduced. This provides an effect that it is possible to provide a fuel pumping characteristic variation correcting method and a fuel pumping characteristic variation correcting device for a high-pressure pump.
In particular, when developing a common rail fuel injection control device, while maintaining the basic control performance of rail pressure control with a metering valve that has been adapted to the operation of the entire device, overshoot amount and undershoot during rail pressure boosting It is possible to realize more appropriate rail pressure control by suppressing and improving the amount.
In addition, even if the pumping amount of the metering valve changes due to deterioration, etc., it is corrected as a variation in the metering valve, so that the metering valve can be used continuously, which contributes to the extension of the life of the high-pressure pump. There is an effect that it is possible.

It is a block diagram which shows the structural example in the connection state of the fuel pumping characteristic dispersion | variation correction apparatus and common rail type fuel-injection control apparatus in embodiment of this invention. 3 is a subroutine flowchart showing a procedure of fuel pressure feed characteristic variation correction processing for a high-pressure pump in the embodiment of the present invention, which is executed by the fuel pressure feed characteristic variation correction apparatus shown in FIG. 1. 3 is a subroutine flowchart showing a specific processing procedure of a pre-correction rail pressure characteristic acquisition process executed in a fuel pumping characteristic variation correction process of the high-pressure pump shown in FIG. 2. 3 is a subroutine flowchart showing a specific processing procedure of correction coefficient calculation processing executed in fuel pumping characteristic variation correction processing of the high-pressure pump shown in FIG. 2. It is a characteristic diagram which shows an example of the change characteristic of the energization current of the metering valve with respect to the fuel pumping amount of a high pressure pump.

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5.
The members and arrangements described below do not limit the present invention and can be variously modified within the scope of the gist of the present invention.
First, the configuration of the connection state between the fuel pumping characteristic variation correcting device and the common rail fuel injection control device according to the embodiment of the present invention will be described with reference to FIG.

The fuel pumping characteristic variation correcting device 102 according to the embodiment of the present invention is used in a so-called service tool (inspection device) used for vehicle operation inspection at the time of vehicle maintenance at a vehicle maintenance factory or the like, and fuel for a high-pressure pump described later. This is realized by installing a pressure feed characteristic variation correction processing function.
That is, the fuel pumping characteristic variation correcting device 102 according to the embodiment of the present invention is assumed to be used by an inspector who inspects a vehicle in an automobile dealer, a vehicle maintenance shop, or the like. As described above, it is used by being connected to the electronic control unit 4 constituting the common rail fuel injection control device 101 of the vehicle.
The fuel pumping characteristic variation correcting device 102 is configured to have a storage element (not shown) such as a RAM or a ROM, etc., centering on a microcomputer (not shown) having a known and well-known configuration, for example. It is what has been made.

On the other hand, the common rail fuel injection control device 101 includes a high-pressure pump device 50 that pumps high-pressure fuel, a common rail 1 that stores high-pressure fuel pumped by the high-pressure pump device 50, and high-pressure fuel supplied from the common rail 1. A plurality of fuel injection valves 2-1 to 2-n to be supplied to the cylinders of the engine 3 and an electronic control unit (indicated as “ECU” in FIG. 1) for executing a fuel injection control process and a rail pressure control process to be described later. ) 4 is the main component.
Such a configuration itself is the same as the basic configuration of this type of fuel injection control apparatus that has been well known.

The high-pressure pump device 50 has a known and well-known configuration in which the supply pump 5, the metering valve 6, and the high-pressure pump 7 are configured as main components.
In this configuration, the fuel in the fuel tank 9 is pumped up by the supply pump 5 and supplied to the high-pressure pump 7 through the metering valve 6. As the metering valve 6, an electromagnetic proportional control valve is used, and the amount of energization is controlled by the electronic control unit 4, so that the flow rate of fuel supplied to the high-pressure pump 7, in other words, the discharge of the high-pressure pump 7. The amount is to be adjusted.

A return valve 8 is provided between the output side of the supply pump 5 and the fuel tank 9 so that surplus fuel on the output side of the supply pump 5 can be returned to the fuel tank 9. .
The supply pump 5 may be provided separately from the high-pressure pump device 50 on the upstream side of the high-pressure pump device 50 or may be provided in the fuel tank 9.
The fuel injection valves 2-1 to 2-n are provided for each cylinder of the engine 3, and are supplied with high-pressure fuel from the common rail 1, and perform fuel injection by injection control by the electronic control unit 4. Yes.

The common rail 1 of the present invention is provided with a pressure control valve 12 by an electromagnetic proportional control valve in a return passage (not shown) for returning surplus high-pressure fuel to the tank 9, and controls the rail pressure together with the metering valve 6. To be used. Instead of the electromagnetic pressure control valve 12, a so-called mechanical pressure safety valve that opens at a constant pressure may be used.
In the embodiment of the present invention, appropriate rail pressure control can be realized by appropriately changing the operation states of the metering valve 6 and the pressure control valve 12 in accordance with the operation state of the engine 3. It has become.

The electronic control unit 4 has, for example, a microcomputer (not shown) having a known and well-known configuration, a storage element (not shown) such as a RAM and a ROM, and a fuel injection valve 2- A drive circuit (not shown) for driving 1 to 2-n and an energization circuit (not shown) for energizing the metering valve 6 and the pressure control valve 12 are configured as main components. It has become a thing.
In addition to the detection signal of the pressure sensor 11 that detects the pressure of the common rail 1 being input to the electronic control unit 4, various detection signals such as the engine speed, the accelerator opening degree, and the fuel temperature are received from the engine 3. It is input for use in operation control and fuel injection control.

Next, the fuel pressure feed characteristic variation correction processing of the high pressure pump in the embodiment of the present invention executed by the fuel pressure feed characteristic variation correction apparatus 102 will be described with reference to FIGS.
FIG. 2 is a subroutine flowchart showing the overall procedure of the fuel pressure feed characteristic variation correction process of the high pressure pump in the embodiment of the present invention, which is executed by the fuel pressure feed characteristic variation correction apparatus 102. First, FIG. The overall procedure of the fuel pumping characteristic variation correction process of the high-pressure pump in the embodiment of the present invention will be described with reference to FIG.
First, when executing the fuel pumping characteristic variation correction processing of the high pressure pump described below, as a precondition, a vehicle (not shown) on which the common rail fuel injection control device 101 described above is mounted has a side brake. It is assumed that the engine 3 is in a state where it is running.

Under such a premise, when the processing is started by the fuel pumping characteristic variation correcting device 102, first, the electronic control unit 4 performs electronic control from the fuel pumping characteristic variation correcting device 102 so that a warm-up operation state is established. A predetermined command (command) is sent to the control unit 4 (see step S100 in FIG. 2).
In this warm-up operation state, the fuel pumping characteristic variation correcting device 102 determines that the engine coolant temperature, which is one of various data relating to the vehicle operation state acquired by the electronic control unit 4, has reached a predetermined stable state. If so, the process proceeds to step S200 described below.

In step S200, the rail pressure characteristics before the later-described variation correction is acquired via the electronic control unit 4, and the acquired data is stored in an appropriate storage area of the fuel pumping characteristic variation correction apparatus 102. It is to be remembered.
Next, based on the rail pressure characteristic acquired as described above, the correction coefficient for correcting the variation is calculated in the fuel pumping characteristic variation correcting device 102 (see step S300 in FIG. 2).

Subsequently, the rail pressure characteristic after the variation correction is performed is acquired via the electronic control unit 4, and the acquired data is stored in an appropriate storage area of the fuel pumping characteristic variation correction device 102. (See step S400 in FIG. 2).
That is, in the electronic control unit 4, in order to obtain the target fuel injection amount to the fuel injection valves 2-1 to 2-n calculated according to the operation state, the energization current to be supplied to the metering valve 6 is normally , Obtained based on the current-carrying current characteristic of the metering valve 6 with respect to the fuel pumping amount Q of the high-pressure pump 7 stored in advance in the electronic control unit 4 (hereinafter referred to as “IQ characteristic” for convenience of explanation). In step S400, the energization amount I is corrected using the correction coefficient calculated as described above, and the metering valve 6 is energized. Thus, the rail pressure characteristics are acquired in the same manner as in step S200.

Next, the fuel pumping characteristic variation correcting device 102 determines whether or not the variation correction is appropriate depending on whether or not the rail pressure characteristic after variation correction acquired as described above is within the reference. If it is determined that the correction is not appropriate (in the case of NO), the process returns to the previous step S200, and the series of processes is repeated again (see step S500 in FIG. 2). On the other hand, if it is determined in step S500 that the variation correction is appropriate (in the case of YES), the correction coefficient (FIG. 5) previously acquired from the fuel pumping characteristic variation correction device 102 to the electronic control unit 4 is displayed. 2 (see step S300 in FIG. 2) is stored in a suitable storage area as a learning value for the correction coefficient, the correction coefficient is stored as a learning value in the electronic control unit 4, and a series of processes is completed ( (See step S600 in FIG. 2).
The electronic control unit 4 corrects the energization current of the metering valve 6 obtained from the standard IQ characteristics stored in advance using the correction coefficient stored as the learning value, and the correction result. The metering valve 6 is driven with the actual energization current.

FIG. 3 shows a more specific processing procedure of the above-described pre-correction rail pressure characteristic acquisition processing in a subroutine flowchart, and the contents thereof will be described below with reference to FIG.
Initially, this pre-correction rail pressure characteristic acquisition process will be described generally. This process automatically sets the accelerator opening to a predetermined opening by the fuel pumping characteristic variation correction device 102 via the electronic control unit 4. The operation (accelerator step operation) is repeated a plurality of times, the actual rail pressure at each opening is obtained, and the maximum value (Max value) and average value are calculated.

More specifically, first, when the processing by the fuel pumping characteristic variation correcting device 102 is started, the value of the first step operation variable na is initially set to zero (see step S202 in FIG. 3). Next, an accelerator step operation is performed between the accelerator opening 0% and 100%, and the actual rail pressure is acquired (see step S204 in FIG. 3).
That is, the accelerator opening degree is changed from 0% to 100% by the fuel pumping characteristic variation correcting device 102 via the electronic control unit 4, and after 100% is maintained for a predetermined time, the operation is returned to 0% (accelerator step operation). ) Will be performed. Here, the predetermined time is preferably about 3 seconds, for example, but is not limited thereto.

  Then, along with the above-described step accelerator operation, the actual rail pressure at each of the opening degrees 0% and 100% is acquired by reading the detection signal of the pressure sensor 11 into the electronic control unit 4, and the fuel pumping characteristic variation correcting device 102 It is stored in an appropriate storage area. Note that, at the time of acquiring the above-described actual rail pressure, the target rail pressure at each accelerator opening is also stored together with the actual rail pressure acquired in an appropriate storage area of the fuel pumping characteristic variation correction device 102. Here, the target rail pressure is calculated and calculated in accordance with the accelerator opening in the fuel injection control process that is executed in the electronic control unit 4 as in the prior art.

Next, the first step operation variable na is updated as na = na + 1 (see step S206 in FIG. 3). Thereafter, whether or not the first step operation variable na has reached the first predetermined value Na. Is determined (see step S208 in FIG. 3).
Therefore, when it is determined in step S208 that the first predetermined value Na has been reached (in the case of YES), the process proceeds to the processing of step S210 described below, while still reaching the first predetermined value Na. If it is determined that there is not (NO), the process returns to the previous step S204, and the above-described process is repeated.
Here, the first predetermined value Na is the number of executions of the accelerator step operation, and should be arbitrarily selected. For example, about 5 is preferable.

  In step S210, an accelerator step operation between the accelerator opening 50% and 100% is performed and the actual rail pressure is acquired. That is, the accelerator opening degree is changed from 50% to 100% by the fuel pumping characteristic variation correcting device 102 via the electronic control unit 4, and the operation of returning to 50% after maintaining the accelerator opening degree 100% for a predetermined time is performed. Will be done. Here, as the predetermined time, for example, about 3 seconds is preferable as in the case of the accelerator step operation in the previous step S204, but is not limited thereto.

Further, in step S210, along with the above step accelerator operation, the actual rail pressure at each of the opening degrees of 50% and 100% is acquired by reading the detection signal of the pressure sensor 11 into the electronic control unit 4, and the fuel pressure feed. It is stored in an appropriate storage area of the characteristic variation correction apparatus 102.
As in the process of step S204, when the actual rail pressure is acquired, the target rail pressure at each accelerator opening is also acquired in the appropriate storage area of the fuel pressure feed characteristic variation correcting device 102 at the same time. Stored with pressure.

Next, the second step operation variable na is updated as nb = nb + 1 (see step S212 in FIG. 3), and then, whether or not the second step operation variable nb has reached the second predetermined value Nb. Is determined (see 214 in FIG. 3).
Therefore, when it is determined in step S214 that the second predetermined value Nb has been reached (in the case of YES), the process proceeds to the process of step S216 described below, while still reaching the second predetermined value Nb. If it is determined that there is not (NO), the process returns to the previous step S210 and the above-described process is repeated (see step S214 in FIG. 3).
Here, the second predetermined value Nb is the number of times the accelerator step operation is executed, and should be arbitrarily selected. For example, the second predetermined value Nb is preferably about 5 times like the first predetermined value Na. .

Next, a maximum value (Max value) and an average value are calculated for the actual rail pressure acquired in the above-described accelerator step operation (see Steps S204 and S210 in FIG. 3) (see Step S216 in FIG. 3).
That is, the maximum value and the average value of the actual rail pressure when the accelerator opening degree is 0% and when the opening degree is 0% in 100% Na reciprocation are calculated, respectively. The maximum value and the average value of the pressure are calculated.

In addition, the maximum and average values of the actual rail pressure when the accelerator opening is 50% and when the opening is 50% in 100% Nb reciprocation are calculated. Similarly, the actual rail when the opening is 100% is calculated. The maximum value and the average value of the pressure are calculated.
The maximum value and the average value of the rail pressure calculated as described above are stored in an appropriate storage area of the fuel pumping characteristic variation correcting device 102 (see step S218 in FIG. 3), and a series of processing is ended and the main Return to the routine.

  The series of processes described above has been described as a more specific processing procedure in step S200. However, the series of processes is related to the corrected rail pressure characteristic acquisition process (step S400) in FIG. Therefore, the above description can be replaced with the description of the specific processing procedure in step S400.

Next, FIG. 4 shows a more specific processing procedure of the correction coefficient calculation process (see step S300) described above with reference to FIG. 2 in a subroutine flowchart. The contents will be described.
When the processing is started by the fuel pumping characteristic variation correcting device 102, the average value of the actual rail pressure obtained previously (see step S216 in FIG. 3) and the corresponding target rail according to a predetermined correction coefficient calculation formula. The correction coefficient K is calculated using the pressure as an input parameter (see step S302 in FIG. 4). Here, the correction coefficient calculation expression is an arithmetic expression set so that an appropriate correction coefficient is determined from the average value of the actual rail pressure and the target rail pressure based on the test result, the simulation result, and the like.

When the average value of the actual rail pressure is higher than the target rail pressure, the correction coefficient in the embodiment of the present invention is adjusted by adjusting the energizing current of the metering valve 6 in the direction in which the actual rail pressure is lowered, and vice versa. In addition, when the average value of the actual rail pressure is lower than the target rail pressure, it is determined to adjust the energization current of the metering valve 6 in the direction in which the actual rail pressure is increased.
For example, FIG. 5 shows an example of IQ characteristics when the metering valve 6 is a normally open type, that is, a type in which the valve is fully opened in a non-energized state. The change of the correction coefficient in the case of this characteristic example will be specifically described with reference to FIG.

First, in relation to the energization current required for the metering valve 6 in order to obtain a certain target discharge amount of the high-pressure pump 7, there is almost no cause due to the characteristic variation of the metering valve 6, which corresponds to a so-called standard product. In this case, it is assumed that the energization current required for the metering valve 6 to obtain the target discharge amount Qa is Ia (see FIG. 5).
On the other hand, when the characteristics of the metering valve 6 vary and the actual rail pressure becomes higher than the target rail pressure as described above, it is necessary to reduce the discharge amount of the high-pressure pump 7, as shown in FIG. In the case of the indicated IQ characteristic, the discharge amount can be reduced by increasing the energization current by ΔI from the previous Ia. Therefore, the correction coefficient in this case is set so that the energization current can be increased beyond Ia in consideration of the correlation between the discharge amount of the high-pressure pump 7 and the rail pressure that are obtained in advance.

Contrary to the above, when the actual rail pressure is lower than the target rail pressure, it is necessary to increase the discharge amount of the high-pressure pump 7. In this case, the energization current is decreased by ΔI from the previous Ia. By doing so, the discharge amount can be increased. Therefore, the correction coefficient in this case is set so that the energization current can be reduced below Ia in consideration of the correlation between the discharge amount of the high-pressure pump 7 and the rail pressure that are obtained in advance.
The metering valve 6 is not necessarily limited to the normally open type as described above, and may be a normally closed type. In this case, the IQ characteristic is such that the discharge amount of the high-pressure pump 7 increases as the current flow of the metering valve 6 increases.

Next, the drive current (energization current value) value of the metering valve 6 is corrected using the correction coefficient calculated as described above (see step S304 in FIG. 4).
That is, the energization amount (current value) I of the metering valve 6 in the IQ characteristic stored in an appropriate region of the electronic control unit 4 is corrected by the correction coefficient calculated as described above. .
As a more specific example of the correction using the correction coefficient, the energization current of the metering valve 6 before correction is multiplied by the correction coefficient, and the multiplication result is used as the energization current of the metering valve 6 subjected to variation correction. The method used is preferred.
The corrected current value I is stored in an appropriate storage area of the fuel pumping characteristic variation correcting device 102 together with the corresponding target fuel pumping amount (target discharge amount) Q, and a series of processing is terminated and the process returns to the main routine. Will return.

Next, a more specific procedure for determining whether or not variation correction is appropriate (see step S500 in FIG. 2) will be described.
When the rail pressure characteristic after the variation correction is performed is performed according to the processing shown in FIG. 3, the determination as to whether or not the variation correction is appropriate is made after the correction acquired according to the processing procedure of FIG. It is determined whether the average value at each accelerator opening calculated for the actual rail pressure (see step S216 in FIG. 3) is within a predetermined range, for example, 5% with respect to a predetermined reference pressure. It is done by doing.

  That is, if the average value of the actual rail pressure after correcting the variation in each accelerator opening is within 5% of the reference pressure predetermined for each accelerator opening, for example, the variation correction is performed. On the other hand, if the average value of the actual rail pressure after correction exceeds 5% with respect to the reference pressure, it is determined that the variation correction is not appropriate. In addition, an appropriate value should be determined for the reference pressure according to the specific specification of the common rail fuel injection control device.

  The present invention is suitable for a common rail fuel injection control device in which it is desired to correct variation in pumping characteristics of a high-pressure pump without incurring a burden on an electronic control unit of a vehicle.

DESCRIPTION OF SYMBOLS 1 ... Common rail 2-1-2-n ... Fuel injection valve 3 ... Engine 4 ... Electronic control unit 6 ... Metering valve 7 ... High pressure pump 11 ... Pressure sensor 12 ... Pressure control valve

Claims (6)

The fuel in the fuel tank is pressurized and pumped to the common rail by the high-pressure pump, enabling high-pressure fuel injection to the engine via the fuel injection valve connected to the common rail, and at least metering to the upstream side of the high-pressure pump A fuel for the high-pressure pump in a common rail fuel injection control device mounted on a vehicle, provided with a valve and configured so that at least the metering valve is driven and controlled by an electronic control unit to control the rail pressure of the common rail. A method for correcting variations in pumping characteristics,
The vehicle is brought into a predetermined driving state from the outside via the electronic control unit,
In such an operating state, the accelerator opening is changed stepwise via the electronic control unit, and the actual rail pressure at each accelerator opening is acquired as the actual rail pressure before correction,
Based on the acquired actual rail pressure before correction and the target rail pressure, the metering valve of the metering valve in a relative relationship between the energizing current of the metering valve stored in the electronic control unit and the discharge amount of the high-pressure pump is stored. Calculate the correction coefficient to correct the energization current,
The electronic control unit performs correction of the energization current of the metering valve using the calculated correction coefficient, and based on the relative relationship between the corrected energization current of the metering valve and the discharge amount of the high-pressure pump. To change the accelerator opening in stages, and obtain the actual rail pressure at each accelerator opening as the corrected actual rail pressure,
It is determined whether or not the change in the corrected actual rail pressure is appropriate. If it is determined that the change in the corrected actual rail pressure is appropriate, the correction coefficient is stored in the electronic control unit, If it is determined that the change in the actual rail pressure after correction is not appropriate, a series of processes after acquisition of the actual rail pressure before correction is performed until it is determined that the change in actual rail pressure after correction is appropriate. The method of correcting variation in fuel pumping characteristics of a high-pressure pump, characterized in that the same is repeated. Calculation of the correction coefficient for correcting the energization current of the metering valve based on the actual rail pressure before correction and the target rail pressure is as follows:
When the average value of the actual rail pressure before correction is higher than the target rail pressure, the energizing current of the metering valve is adjusted in the direction in which the actual rail pressure is reduced, while the average value of the actual rail pressure before correction is the target value. 2. The high-pressure pump according to claim 1, wherein when the rail pressure is lower than the rail pressure, it is calculated by an arithmetic expression determined to adjust the energizing current of the metering valve in a direction in which the actual rail pressure is increased. Fuel pumping characteristics variation correction method. The determination as to whether or not the change in the actual rail pressure after correction is appropriate is as follows:
It is determined whether or not the average value of the corrected actual rail pressure is within a predetermined range, and when it is determined that the average rail pressure is within the predetermined range, the change in the corrected actual rail pressure is assumed to be appropriate. The method for correcting variation in fuel pumping characteristics of a high-pressure pump according to claim 2. The fuel in the fuel tank is pressurized and pumped to the common rail by the high-pressure pump, enabling high-pressure fuel injection to the engine via the fuel injection valve connected to the common rail, and at least metering to the upstream side of the high-pressure pump A fuel for the high-pressure pump in a common rail fuel injection control device mounted on a vehicle, provided with a valve and configured so that at least the metering valve is driven and controlled by an electronic control unit to control the rail pressure of the common rail. A fuel pumping characteristic variation correcting device for correcting variations in pumping characteristics,
The fuel pumping characteristic variation correcting device is
Via the electronic control unit, the vehicle is brought into a predetermined driving state,
In such an operating state, the accelerator opening is changed stepwise via the electronic control unit, and the actual rail pressure at each accelerator opening is acquired as the actual rail pressure before correction,
Based on the acquired actual rail pressure before correction and the target rail pressure, the metering valve of the metering valve in a relative relationship between the energizing current of the metering valve stored in the electronic control unit and the discharge amount of the high-pressure pump is stored. Calculate the correction coefficient to correct the energization current,
The electronic control unit performs correction of the energization current of the metering valve using the calculated correction coefficient, and based on the relative relationship between the corrected energization current of the metering valve and the discharge amount of the high-pressure pump. To change the accelerator opening in stages, and obtain the actual rail pressure at each accelerator opening as the corrected actual rail pressure,
It is determined whether or not the change in the corrected actual rail pressure is appropriate. If it is determined that the change in the corrected actual rail pressure is appropriate, the correction coefficient is stored in the electronic control unit, If it is determined that the change in the actual rail pressure after correction is not appropriate, a series of processes after acquisition of the actual rail pressure before correction is performed until it is determined that the change in actual rail pressure after correction is appropriate. The fuel pumping characteristic variation correcting device is configured to be repeated in the same manner. Calculation of the correction coefficient for correcting the energization current of the metering valve based on the actual rail pressure before correction and the target rail pressure is as follows:
When the average value of the actual rail pressure before correction is higher than the target rail pressure, the energizing current of the metering valve is adjusted in the direction in which the actual rail pressure is reduced, while the average value of the actual rail pressure before correction is the target value. 5. The fuel pumping characteristic according to claim 4, wherein when the rail pressure is lower than the rail pressure, the fuel pumping characteristic is calculated by an arithmetic expression determined to adjust an energization current of the metering valve in a direction in which the actual rail pressure is increased. Variation correction device. The determination as to whether or not the change in the actual rail pressure after correction is appropriate is as follows:
It is determined whether or not the average value of the corrected actual rail pressure is within a predetermined range, and when it is determined that the average rail pressure is within the predetermined range, the change in the corrected actual rail pressure is assumed to be appropriate. 6. The fuel pumping characteristic variation correcting device according to claim 5,

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