WO2005038224A1

WO2005038224A1 - Fuel injection control unit

Info

Publication number: WO2005038224A1
Application number: PCT/JP2004/015549
Authority: WO
Inventors: Takao Miyawaki; Hiroto Fujii; Atsushi Kishi; Atsushi Ueda
Original assignee: Bosch Automotive Systems Corporation
Priority date: 2003-10-17
Filing date: 2004-10-14
Publication date: 2005-04-28
Also published as: JP2005120952A

Abstract

A fuel injection control unit (7) for controlling fuel injection, comprising a target injection amount calculation part (40) and a correction calculation part (50) performing calculation for providing a corrective target fuel injection amount necessary for providing a target fuel injection amount by an injector (4-1). The correction calculation part (50) further comprises a first calculation part (51) responding to the target fuel injection amount and the target pressure of high-pressure fuel and calculating a standard target fuel injection amount based on standard fuel injection characteristic data in the cylinder of the injector (4-1), a data storage part (53) storing individual fuel injection characteristic data on the outside of the cylinder of the injector (4-1), a second calculation part (52) calculating a correction value for the standard target fuel injection amount based on the standard target fuel injection amount and the individual fuel injection characteristic data, and a third calculation part (54) calculating the corrective target fuel injection amount based on the correction value and the standard target fuel injection amount. Thus, more accurate fuel injection control is enabled in consideration of the effects of a cylinder pressure.

Description

Description Fuel injection control device Technical field

The present invention relates to a fuel injection control device in a common rail type fuel injection system. Background art

The common rail type fuel injection system is a system that uses a variable discharge high pressure pump to directly inject high pressure fuel of a predetermined pressure stored in the common rail into each cylinder of the internal combustion engine using an injector. . The control of fuel injection from the injector is performed by opening and closing the solenoid valve according to the injection timing and injection amount calculated by an electronic control unit configured using a microcomputer. In the common rail fuel injection system configured as described above, it is required that the pressure of the high-pressure fuel applied to the injector be as high as 10 OMPa and that the metering accuracy be high. Therefore, the machine difference between the injectors greatly affects the control accuracy. In order to meet this demand, the fuel injection characteristics of the injector alone are measured in advance, and based on the measurement results, an information storage medium storing individual identification information is attached to the corresponding injector, and the There has been proposed a configuration in which a control unit can take in this identification information and perform fuel injection control according to the individual fuel injection characteristics of the injector (Japanese Patent Application Laid-Open No. 2000-22085). No.).

In addition, the inspection points of the fuel injection characteristics of the injectors are set to, for example, four points, and all the products are measured on the injector production line.In addition, in order to correct the variation between the samples of the injector fuel injection characteristics, Measure the correlation between the measurement results at three of the four inspection points above and other areas on the injector manufacturing line, and use the correlation to correct the variation in the fuel injection characteristics over the entire usage area. Such techniques are also known. In general, the fuel injection characteristics of injectors are affected by the cylinder pressure, so the fuel injection characteristics when the injectors are actually mounted on cylinders and the cylinders measured using a test bench on the injector production line. It differs from the external fuel injection characteristics. However, in the above prior art, since the fuel injection characteristic value used in the correction value calculation is the out-of-cylinder fuel injection characteristic measured on the injector manufacturing line, the correction operation tends to be overcorrection. Has problems. To solve this problem, it is sufficient to attach each injector to a cylinder and measure the in-cylinder fuel injection characteristics, but this method is not feasible.

An object of the present invention is to provide a fuel injection control device that can solve the above-described problems in the related art.

Another object of the present invention is to provide a fuel injection control device capable of performing more accurate fuel injection control in consideration of the influence of the in-cylinder pressure. Disclosure of the invention

According to the present invention, the injection characteristics of a single injector are measured by both the injector tester and the engine bench, and the difference between the fuel injection amount inside the engine cylinder and the difference between the fuel injection amount outside the engine cylinder (ratio ) Is reflected in the capture control.

A feature of the present invention is a fuel injection control device for injecting high pressure fuel in a common rail into a combustion chamber of an internal combustion engine by an injector, wherein a target injection amount calculation for calculating a target fuel injection amount corresponding to an operation state of the internal combustion engine is provided. And a controller for detecting the target fuel injection amount according to the fuel injection characteristic of the engine, and obtaining a corrected target fuel injection amount necessary for obtaining the target fuel injection amount by the injector. And a driving unit for driving the injector in accordance with the corrected target fuel injection amount, wherein the correction calculation unit includes the target fuel injection amount and the high pressure. A first calculating unit that calculates a standard target fuel injection amount based on standard fuel injection characteristic data at the cylinder of the injector in response to the actual fuel pressure; and an indicator outside the cylinder of the injector. A data storage unit for the fuel injection characteristic data is stored, the standard target fuel based the on the standard target fuel injection amount and the individual fuel injection characteristic data A second calculation unit for calculating a correction value for the injection amount; and a third calculation unit for calculating the correction target fuel injection amount based on the correction value and the standard target fuel injection amount. You. Brief Description of Drawings

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of the control unit of FIG.

FIG. 3 is a detailed block diagram of the first calculation unit in FIG.

FIG. 4 is a detailed block diagram of the second calculation unit in FIG.

FIG. 5 is a block diagram showing a configuration of a fourth calculation unit added to the correction calculation unit of FIG.

FIG. 6 is a block diagram showing a main part of a modification of the correction calculation unit of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a schematic configuration diagram showing one embodiment of a common rail fuel injection device provided with a fuel injection control device according to the present invention. The fuel injection device 1 is a common rail type fuel injection device for an internal combustion engine for injecting and supplying fuel to an internal combustion engine of an internal combustion engine vehicle, and includes a common rail 2 and a high pressure pump assembly for supplying high pressure fuel to the common rail 2. 3 and a plurality of injectors 4-1 to inject the high-pressure fuel stored in the common rail 2 into each of the cylinders 11-1 to 11-1 of the N-cylinder diesel engine 10 to the N combustion chamber. 4 with N.

These injectors 4-1 to 4-1N are provided with fuel injection control solenoid valves V1 to VN, respectively. These solenoid valves V1 to VN are independently controlled to be opened and closed by an injector drive circuit 13, so that a required amount of high-pressure fuel can be injected into a corresponding cylinder at a required time. The rotation output from the output shaft 12 of the diesel engine 10 is transmitted to a wheel drive device (not shown) including a transmission. The high-pressure pump assembly 3 is a high-pressure pump driven by a diesel engine 10. It has a known configuration in which a pump main body 31, a fuel metering unit 32, and an inlet / outlet valve 33 are integrally assembled. Fuel in the fuel tank 5 is supplied to the fuel metering unit 32 by a feed pump 6. Adjustment of the fuel supply amount in the fuel metering unit 32 is controlled by opening and closing a solenoid valve 34 provided in the fuel metering unit 32 by a drive control signal SV from the control unit 7. It is done by doing.

The control unit 7 receives the actual pressure signal PA from the pressure sensor 8 that detects the actual fuel pressure in the common rail 2 and the rotational speed sensor 9A from which the diesel engine 10 rotates. Is input from the accelerator sensor 9 B. c The control unit 7 has a vehicle speed sensor 9 C as well as an accelerator signal A indicating an operation amount of an accelerator pedal (not shown). , A vehicle speed signal V indicating a vehicle speed, a water temperature signal W indicating a cooling water temperature of the diesel engine 10 from a water temperature sensor 9D, and a battery voltage signal VB indicating a terminal voltage of a battery (not shown).

FIG. 2 is a block diagram showing the configuration of the control unit 7. Here, only the configuration of the control system for driving the injectors 4-1 to 4-1N is shown, and the control system of the high-pressure pump assembly 3 is omitted in the drawing.

In FIG. 2, reference numeral 40 denotes a target injection amount calculation unit that calculates a target fuel injection amount corresponding to the operating state of the diesel engine 10 in response to the rotation speed signal N and the accelerator signal A. A target amount signal QT indicating the calculated target fuel injection amount is output from the target injection amount calculating section 40. The reference numeral 50 denotes a correction operation unit. In the correction operation unit 50, the target injection amount operation unit 40 performs an operation in accordance with the fuel injection characteristics of the injector 41 actually used. The corrected target fuel injection amount is corrected, and the injector 411 executes a calculation for obtaining the corrected target fuel injection amount necessary for actually obtaining the target fuel injection amount indicated by the target amount signal QT.

The correction calculation unit 50 responds to the target amount signal QT and the actual pressure signal PA, and provides standard data of in-cylinder fuel injection characteristic data when the injector 41 is actually mounted on the cylinder of the internal combustion engine. Based on the standard fuel injection characteristic data It has a first calculation unit 51 for performing calculation.

As shown in FIG. 3, the first arithmetic unit 51 responds to the target amount signal QT and the actual pressure signal PA, and obtains the target fuel injection amount indicated by the target amount signal QT at the rail pressure at that time. Calculates the injector injection time required for this, and outputs an injection time signal T indicating the injection time obtained as a result of the calculation. The calculation of the injection time calculation unit 51A can be a map calculation based on a map data representing a relationship among the target fuel injection amount, the rail pressure, and the injection time.

The injection time signal T is input to the injection amount calculating section 51B to which the actual pressure signal PA is input, where the standard injection amount is calculated based on the standard fuel injection characteristic data. This standard injection amount was obtained by injecting fuel for the injection time given by the injection time signal T under the common rail pressure given by the actual pressure signal PA when using a standard injector attached to the cylinder. A signal indicating the standard injection amount calculated by the injection amount calculation unit 51B, which is the fuel injection amount that would be obtained in this case, is output as the standard target fuel injection amount signal QS.

Returning to FIG. 2, the standard target fuel injection amount signal QS is input to the second arithmetic unit 52 to which the actual pressure signal PA is input. Reference numeral 53 denotes a data storage unit in which the fuel injection characteristic data DT unique to the injector 41 is stored. The fuel injection characteristic data DT is individual fuel injection characteristic data obtained by testing the injector 4-1 with a pump tester, and is referred to for calculation in the second calculation unit 52.

Referring to FIG. 4, the second calculation unit 52 includes a correction coefficient calculation unit 52A and a multiplication unit 52B. The correction coefficient calculation unit 52 A responds to the standard target fuel injection amount signal QS and the actual pressure signal PA, and uses a correction calculation map provided in advance and based on the machine error of the injectors 411. Map calculation of the correction coefficient for calculating the correction amount of the fuel injection amount. The correction coefficient signal F indicating the correction coefficient obtained by this calculation is supplied to the multiplication unit 52B, and is multiplied by the raw data DT for fuel injection from the data storage unit 53. As a result, a correction value for the standard target fuel injection amount signal QS is obtained, and a correction value signal G indicating this correction value is output from the multiplier 52B. Returning to FIG. 2, the correction value signal G is input to the third arithmetic unit 54 to which the standard target fuel injection amount signal QS is given, where the standard injection indicated by the standard target fuel injection amount signal QS The correction value indicated by the correction value signal G is added to the value of the amount, whereby the corrected target fuel injection amount is obtained. The target fuel injection amount signal QC indicating the positive target fuel injection amount is obtained from the third arithmetic unit 54.

As described above, the correction calculation unit 50 performs the standard injection that gives an average value correction for the given target fuel injection amount based on the standard twist injection characteristic data when the injector 411 is attached to the cylinder. The injector is configured to obtain the fuel injection amount and to correct the standard injection amount with the injector 411. Therefore, it is possible to more accurately detect the fuel injection amount for the injector.

The correction target fuel injection amount signal QC from the correction calculation unit 50 is input to the injection period calculation unit 60 to which the actual pressure signal PA is input, where the injection amount according to the given target amount signal QT The injection period necessary to obtain the above is calculated, and a signal indicating the calculated injection period is output as the injection period signal ET.

Referring to the first time, the injection period signal ET is sent to the injector drive circuit 13. The injector 4-1 is driven by the injector drive circuit 13, and the amount of fuel indicated by the target amount signal QT is accurately injected into the cylinders 111 of the internal combustion engine (not shown).

The correction calculation section 50 and the injection period calculation section 60 shown in FIG. 2 correspond to the injector 411. For each of the other injectors 4-2 to 4-N, a similar correction operation unit and injection period operation unit are provided correspondingly, and for each of the injectors 4-2 to 4-N, The fuel injection amount is corrected according to the fuel injection characteristics, and the amount of fuel according to the target amount signal QT is accurately injected into the other cylinders 1 1 1 2 to 1 1 —N. '

The correction operation unit 50 shown in FIG. 2 is configured to add the correction value signal G output from the second operation unit 52 to the standard target fuel injection amount signal QS in the third operation unit 54. . However, by further processing the correction value signal G, more precise correction is possible. As a result, it is possible to perform fuel control with a higher degree of cleanliness by eliminating the influence of the cylinder pressure. A typical example of the portion affected by the in-cylinder pressure is the nozzle seat diameter.

FIG. 5 shows an example of a configuration for such a correction process. The fourth arithmetic section 55 shown in FIG. 5 is for correcting the influence of the in-cylinder pressure due to the diameter of the nozzle sheet, and further corrects the correction value signal G, and obtains a correction result obtained by the correction processing result. ^positive; and a positive signal J capturing indicates the value is configured to provide the third arithmetic unit 5 4.

55 A has map data for reflecting the degree of influence of the in-cylinder pressure due to the nozzle seat diameter of the injector on the correction amount of the fuel injection amount.Based on this map data, the standard target fuel injection amount signal This is a correction amount calculation unit that performs a map calculation of the correction amount of the fuel injection amount for the small diameter of the nozzle in response to QS ′ and the actual pressure signal PA.

The auxiliary correction amount signal H indicating the correction amount, which is the calculation result of the correction amount calculation unit 55 A, is input to the addition unit 55 B to which the correction value signal G is input. The positive value signal G and the auxiliary correction value signal H are added. As a result, the addition unit 55B obtains a correction amount in which the correction value signal G is further corrected according to the size of the nozzle sheet diameter, and outputs a combined correction value signal J indicating the correction amount. Is done.

Therefore, in the configuration of FIG. 2, the fourth operation unit 55 shown in FIG. 5 is provided between the second operation unit 52 and the third operation unit 54, and the correction value signal G is supplied to the fourth operation unit. 55, and the resulting combined correction value signal J is input to the third arithmetic unit 54 in place of the correction value signal G, so that the nozzle sheet diameter of the injector can be reduced. Can be taken into account. As a result, more precise fuel injection control can be realized.

FIG. 6 is a block diagram showing a main part of a modification of the correction calculation section 50 shown in FIG. The correction calculation unit 50 shown in FIG. 2 is configured to calculate the standard target fuel injection amount signal QS only by the first calculation unit 51, whereas the first calculation unit shown in FIG. In 100, the first to third map operation units 101, 102, and 103 corresponding to the in-cylinder fuel injection waiting time of the injector are prepared, and the first to third map operation units 101 , 102, and 103, the map operation is performed in response to the target amount signal QT and the actual pressure signal PA. These map-calculations are basically the same as the map calculations in the first calculation unit 51. In this way, the standard target fuel injection amount signals QS1, QS2, and QS3 output from the first to third map calculation units 101, 102, and 103 are selected by the selection unit 104. One of the signals is selected as the standard target fuel injection amount signal QS in response to the fuel injection characteristic data DT. The selection unit 104 selects an operation result using map data most suitable for the characteristics of the injector to be used.

According to the configuration shown in FIG. 6, since the map data closer to the in-cylinder fuel injection characteristics of the injector to be used can be used, more precise correction is possible. Industrial applicability

As described above, the fuel injection control device according to the present invention can greatly improve the accuracy of the fuel injection control, and is useful for improving the control of the fuel injection device.

Claims

The scope of the claims

1. In a fuel injection control device for injecting high pressure fuel in a common rail into a combustion chamber of an internal combustion engine by an injector,

A target injection amount calculation unit that calculates a target fuel injection amount corresponding to an operation state of the internal combustion engine;

The target fuel injection amount is corrected according to the fuel injection characteristics of the injector, and a calculation is performed by the injector to obtain a corrected target fuel injection amount required to obtain the target fuel injection amount. A correction operation unit,

A driving unit for driving the injector according to the correction target fuel injection amount,

The correction operation unit,

A first calculation unit that calculates a standard target fuel injection amount based on standard fuel injection characteristic data in a cylinder of the injector in response to the target fuel injection amount and the actual pressure of the high-pressure fuel;

A data storage unit in which individual fuel injection characteristic data outside the cylinder of the injector is stored;

A second calculating unit that calculates a correction value for the standard target fuel injection amount based on the standard target fuel injection amount and the individual fuel injection characteristic data;

A third calculating unit that calculates the corrected target fuel injection amount based on the correction value and the standard target fuel injection amount;

A fuel injection control device characterized by comprising:

2. The apparatus further includes a fourth arithmetic unit that performs a process for further correcting the degree of influence of the in-cylinder pressure due to the nozzle sheet diameter of the injector on the corrected value,

3. The fuel injection system according to claim 1, wherein the calculation unit calculates the correction target fuel injection amount based on a calculation result of the fourth calculation unit and the standard target fuel injection amount. Control device.

3. A unit for calculating the injector injection time required to obtain the target fuel injection amount, in response to the target fuel injection amount and the actual pressure. 2. The fuel injection control device according to claim 1, further comprising: a unit for calculating a standard injection amount based on standard fuel injection characteristic data in response to the injection time and the actual pressure.

4. A unit in which the second calculation unit calculates a correction coefficient for calculating a correction amount of the fuel injection amount based on the machine difference of the injector in response to the standard target fuel injection amount and the actual pressure. 2. The fuel injection control device according to claim 1, further comprising: a unit configured to calculate the correction value based on the correction coefficient and the individual fuel injection characteristic data.

5. The first calculation unit has a plurality of map calculation units according to the in-cylinder fuel injection characteristics of the injector, and each map calculation unit calculates the target fuel injection amount and the actual pressure of the high-pressure fuel. In response, the standard target fuel injection amount is calculated and output, and the standard target fuel injection amount is selected according to the fuel injection characteristic data of the injector. The fuel injection control device according to any one of the preceding claims.