JP2002030984A - Fuel injection control device and actuator control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the need of adjusting the fixed number of parts, and to improve control accuracy in the simplest structure possible. SOLUTION: The moving amount of a pre-stroke actuator 1 is detected by a sensor 2, and converted to digital data by a digital servo IC 5 to be inputted in a CPU 4. An output value of the digital servo IC 5 includes a deviation from an ideal value due to variations in a property of each IC, so that the output values is made to be corrected to the ideal value by canceling out the deviation with a computing expression predetermined in the CPU 4. For canceling out the deviation by the computing expression, a correcting constant established on the basis of a pre-surveyed input/output property of the digital servo IC 5 and memorized in a read only memory 7 is used, thereby improving control accuracy without requiring conventional adjustment for the fixed number of parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fuel injection control, and more particularly to a control device and an actuator control method for improving control characteristics.

[0002]

2. Description of the Related Art In recent years, an electronic control unit called an ECU, which is mainly constituted by a so-called microcontroller, is used for fuel injection control of a vehicle engine.
FIG. 5 shows an example of a conventional configuration of a fuel injection control device for controlling a fuel injection amount and an injection timing using the ECU. The conventional device will be described below with reference to FIG. . The configuration of the fuel injection control device is particularly for controlling the operation of the pre-stroke actuator 1 used for adjusting the start timing of the fuel injection (so-called pre-stroke adjustment). That is, the pre-stroke actuator 1 is provided in, for example, an in-line fuel injection pump (not shown), and a timing sleeve (not shown) in the in-line fuel injection pump that performs a function of setting a fuel injection start timing (setting a pre-stroke). The position () is adjusted by operation control from the ECU 3. The amount of operation of the pre-stroke actuator (denoted as "ACT" in FIG. 5) 1, that is, the amount of rotation of the rotary shaft (not shown) is detected by the sensor 2 and fed back to the ECU 3. , The so-called feedback control of the pre-stroke actuator 1 by the ECU 3. Here, the sensor 2 is, for example,
Something like a variable inductance is used.

The ECU 3 is provided with a CPU 4 for executing various programs and the like, and converts an output signal of the sensor 2 into digital data suitable for use in execution of a pre-stroke actuator control program in the CPU 4. Servo I for
C5 is provided. Further, a drive circuit (in FIG. 5, denoted as “DRV”) 8 for the pre-stroke actuator 1 is provided inside the ECU 3. The drive circuit 8 drives the pre-stroke actuator 1 in accordance with a control signal output by executing the actuator control program in the CPU 4, whereby the pre-stroke actuator 1 is determined by the CPU 4 executing the actuator control program. A predetermined operation of the stroke actuator 1 is obtained.

[0004]

However, in such a configuration, the electrical characteristics of the digital servo IC 5 vary from product to product, so that the output value of the digital servo IC 5 is constant with respect to its input value. In most cases it does not. For this reason, the ECU 3 has a plurality of adjustment resistors 6 a (in FIG. 5, denoted as “adjustment resistor group”) for adjusting the input signal level from the sensor 2 to the digital servo IC 5 in advance. Servo I
A C peripheral circuit 6 is provided. In the manufacturing process of the ECU 3, the input level of the sensor 2 and the input / output characteristics between the digital servo IC 5 and the input / output characteristics of the digital servo IC 5 are adjusted by changing various types of adjustment resistors and are preferably adjusted. An appropriate adjustment resistor is selected to ensure control characteristics. However, the necessity of such adjustment for each ECU not only complicates the manufacturing process and is troublesome, but also causes a high price of the product.

The present invention has been made in view of the above circumstances, and provides a fuel injection control device and an actuator control method which do not require adjustment of component constants and improve control accuracy with a configuration as simple as possible. is there. It is another object of the present invention to provide a fuel injection control device and an actuator control method that improve control accuracy without increasing the price of a product.

[0006]

In order to achieve the above object of the present invention, a fuel injection control device according to the present invention controls the operation of an actuator provided in a fuel injection pump to set a desired condition value for injection. A fuel injection control device configured to be able to set a value of the operation amount, wherein an operation amount detection means for detecting an operation amount of the actuator, and an output signal of the operation amount detection means is converted into predetermined digital data and output. Digital data generating means, an output signal of the digital data generating means, a data processing means for performing predetermined processing and outputting, and an output signal of the data processing means, and determining an operation state of the actuator Operation control means for driving the actuator in accordance with the result of the determination. Process, the output value for an input value of the digital data generating means is made of is configured to cancel the deviation of the input data so that the ideal value set in advance.

In such a configuration, the deviation of the output value of the digital data generating means from the ideal value is offset by the data processing means, so that the adjusting operation by the adjusting resistor as in the prior art becomes unnecessary. In addition, the control accuracy is improved.

In order to achieve the above object of the present invention,
The fuel injection control device according to the present invention is a fuel injection control device configured to be able to set a condition value regarding injection to a desired value by controlling an operation of an actuator provided in a fuel injection pump, A sensor for detecting an operation amount of the actuator, a digital servo IC for converting an output signal of the sensor into predetermined digital data and outputting the digital data, a microcontroller, and driving the actuator according to a control signal from the microcontroller A driving circuit, and a memory in which a correction constant is stored in a readable manner in advance. The microcontroller determines a deviation of an output signal of the digital servo IC from an ideal value by a predetermined arithmetic expression. Offset by using the correction constant stored in Determine the operating state of the actuator Te is made is configured to output a control signal to the drive circuit based on the determination result.

In such a configuration, the digital servo I
Since the deviation of the output value of C from the ideal value is offset by so-called software processing by the CPU, adjustment work with an adjustment resistor as in the related art is not required, and control accuracy is improved. That is what it is.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The members, arrangements, and the like described below do not limit the present invention, and can be variously modified within the scope of the present invention. The same components as those of the conventional device shown in FIG. 5 are denoted by the same reference numerals. First, the configuration of the fuel injection control device according to the present invention is shown in FIG.
This will be described with reference to FIG. This configuration of the fuel injection control device is particularly suitable for controlling the operation of the pre-stroke actuator 1 used for adjusting the start timing of fuel injection (so-called pre-stroke adjustment). That is, the fuel injection control device includes an electronic control device (hereinafter, referred to as “ECU”) 3 used for general engine control,
The prestroke actuator 1 and the sensor 2 are configured as main components.

First, the pre-stroke actuator 1
The position of a timing sleeve (not shown) in the in-line fuel injection pump, which is provided in, for example, an unillustrated in-line fuel injection pump and has a function of setting a start timing of fuel injection (condition value relating to injection), is determined by the ECU 3 The adjustment is performed by the operation control from. The amount of operation of the pre-stroke actuator 1, specifically, the amount of rotation of the rotary shaft (not shown) is detected by a sensor 2 as operation amount detecting means, and is fed back to the ECU 3 so that the ECU 3 controls the operation of the pre-stroke actuator 1. This is provided for so-called feedback control. The sensor 2 is preferably, for example, one having a variable inductance.

The ECU 3 is mainly composed of a so-called microcontroller (hereinafter referred to as a "CPU") 5 and is a core of a control system of a vehicle engine. Upon input, various control programs are executed based on the input, so that pre-stroke control, which will be described later, can be realized. Inside the ECU 3, in addition to the CPU 4, a digital servo IC 5, a digital servo IC peripheral circuit 6, a read-only memory 7, and a drive circuit 8 are provided as necessary for the actuator control.
Digital servo IC5 as digital data generating means
Converts an input signal from the sensor 2 into digital data suitable for use in execution of an actuator control program in the CPU 4.

The digital servo IC 5 requires so-called external resistors, capacitors and the like, and these components are selected and used according to the use conditions of the circuit. Therefore, a plurality of adjustment resistors (hereinafter, referred to as “adjustment resistor group”) 6 a and a digital servo IC 5
Is provided with a digital servo IC peripheral circuit 6 composed of electronic components necessary for so-called external use.
In the embodiment of the present invention, unlike the related art, since the adjustment operation of changing the optimum adjustment resistance value so that the output value of the digital servo IC 5 becomes a desired output value is not performed, the digital servo IC 5 A value recommended by the manufacturer of the digital servo IC 5 is selected as a value of the external resistor required for the operation of the digital servo IC 5, and an adjusting resistor (not shown) having the recommended value is connected. ing.

The read-only memory 7 stores correction constants used in a shift canceling calculation process (details will be described later) executed by the CPU 4, and is used as an IC. In particular, as the read-only memory 7,
It is preferable to use a nonvolatile memory such as an SRAM. The read-only memory 7 is connected to the CPU 4 via a system bus. The drive circuit 8 is for driving the pre-stroke actuator 1, and is configured to supply a necessary drive current to the pre-stroke actuator 1 in accordance with a control signal from the CPU 4. That is, the driving state of the pre-stroke actuator 1 is determined by the execution of the actuator control program by the CPU 4,
A control signal corresponding to the determined driving state is output from the CPU 4 to the driving circuit 8.

Next, the procedure of the prestroke control according to the above configuration will be described with reference to the flowchart shown in FIG. First, the control flow shown in FIG. 2 is one subroutine flow executed in the main flow for engine control executed by the CPU 4. When the subroutine control is started, first, a servo IC output data input process is performed (see step 100 in FIG. 2). That is,
The output signal of the digital servo IC 5 corresponding to the output of the sensor 2 is read into the CPU 4. Next, a shift cancellation calculation process is performed (see step 200 in FIG. 2). First, the relationship between the signal (sensor input recognition value) from the sensor 2 at the input stage of the digital servo IC 5 and the output value of the digital servo IC 5 changes for each digital servo IC (in other words, for each ECU). Instead, it should originally be a fixed relationship, that is, an input / output characteristic (ideal characteristic) represented by a predetermined linear function, for example, as shown by a solid line in FIG.

However, the output value of the digital servo IC 5 is reduced by the variation of the digital servo IC 5 and the variation of the resistance value of the adjusting resistor 6a used in the digital servo IC peripheral circuit 6.
The same value is not always the same for the same input value from the sensor 2 input to the sensor 5 (for example, see the dotted characteristic line in FIG. 3), and a deviation from the ideal value occurs. Therefore, the input signal from the sensor 2 input to the digital servo IC 5 is offset by a predetermined arithmetic expression so that the data output from the digital servo IC 5 becomes an ideal value. The calculation of the ideal value with respect to the value is the shift offset calculation processing. A correction constant is used in the shift offset calculation. This correction constant is obtained in advance by converting the deviation between the actually measured data of the output value of the digital servo IC 5 and the ideal value by a predetermined conversion formula for converting into a correction constant, as described in the correction constant selection method described later. It is read out from the read-only memory 7 and used. As described above, the desired input / output characteristic (ideal characteristic) of the digital servo IC 5 is as shown by a solid line in FIG. 3 and is represented by a linear function. The ideal characteristic is set in advance in consideration of the desired control characteristic of the pre-stroke control by the fuel injection control device, and the operation formula of the offset canceling calculation is set based on this ideal characteristic. Things. When the arithmetic processing is performed using the arithmetic expression in the offset canceling operation, the correction constant set based on the actual input / output characteristics of the servo digital IC 5 is used as described above, and the offset is calculated. The ideal value is obtained by offsetting.

When the ideal value of the output data of the digital servo IC 5 is obtained in the offset canceling calculation process as described above, the prestroke setting process is performed using this ideal value and other data (FIG. 2 step 300). That is, the pre-stroke setting process is
The prestroke actuator 1 is basically the same as the conventional one, and the pre-stroke actuator 1 is driven by the drive circuit 8 based on the ideal value obtained by the above-described offset canceling calculation process and other data.
A predetermined pre-stroke is set as a predetermined driving state via the control unit. Conventionally,
While the output data of the digital servo IC 5 is used for the pre-stroke setting processing, the embodiment of the present invention is different from the conventional one in that the ideal value obtained by the shift offset calculation processing is used as described above. different. Then, after the setting of the pre-stroke, the process returns to the main routine (not shown).

Next, a method of selecting a correction constant stored in advance in the read-only memory 7 will be described with reference to FIG. First, in selecting a correction constant, a standard device 9 having ideal output characteristics of the sensor 2 is used instead of the actual sensor 2 (see FIG. 4). That is, the standard device 9 is connected to a predetermined connection terminal (not shown) of the ECU 3 as in the case where the sensor 2 is connected. As described above, the adjustment resistor 6a in the digital servo IC peripheral circuit 6 has a resistance value recommended by the IC manufacturer, as described above. Then, the output of the standard device 9 is variously changed, and the output value of the digital servo IC 5 for each output is measured. Next, each output value of the digital servo IC 5 and the digital servo I with respect to each output value of the standard device 9 when each output value of the digital servo IC 5 is obtained.
The amount of deviation from the ideal output value (ideal value) of C5 is calculated.
On the other hand, an ideal input / output characteristic of the digital servo IC 5 is known in advance, and an arithmetic expression for correcting the output value of the digital servo IC 5 to an ideal value based on the input / output characteristic is obtained except for a specific value of the correction constant. The basic formula is set in advance. The correction constant is determined based on the actual shift amount obtained previously, and is written to the read-only memory 7.

Next, the state of the pre-stroke control when the above-described shift canceling calculation processing is not performed (before adjustment) and the state of the pre-stroke control when the shift cancellation calculation processing is performed (after adjustment) are described. Compared with FIG. 4 in general, first, when the shift cancellation operation is not performed,
In other words, in the conventional configuration, when the input from the standard device 9 is made, the digital servo control data used for the pre-stroke control roughly includes two types of errors (deviations). Become. That is, one of them occurs between the digital servo IC 5 and the standard device 9, which is mainly caused by the variation of the adjustment resistor 6 a of the digital servo IC peripheral circuit 6. FIG.
In the figure, the portion described as “before adjustment” schematically shows this conventional configuration, and the so-called hatched ellipse shown between the digital servo IC 5 and the standard device 9 is the It expresses the gap. The other shift is a shift in the output value caused by a variation in the resistance value of the adjusting resistor 6a and a variation in the output characteristics of the digital servo IC 5 itself.
The portion schematically showing the conventional configuration described as “before adjustment”, which is represented by a hatched circle on the output side of the digital servo IC 5. After all, the control data for digital servo used in the pre-stroke control by software includes the above two shifts,
Those that deviate from the ideal values are used as they are.

On the other hand, when the offset canceling operation is performed (after adjustment), the standard unit 9 and the digital servo IC
5 is the same as before the adjustment. In FIG. 4, in the portion described as “after adjustment”, this shift is represented by a so-called hatched ellipse, as in the case before the adjustment. Although the output value shift due to the variation in the output characteristics of the digital servo IC 5 itself exists as before the adjustment, the shift offset calculation process using the correction constant set based on the actual data is performed, The two types of shifts described above are canceled out, and as a result, the ideal value is used as the digital servo control data used in the pre-stroke control by software. Therefore, if the sensor 2 is adjusted to have the same output characteristics as the standard device 9 and is connected to the ECU 3, pre-stroke control in which the deviation is canceled out is performed.

In the embodiment of the invention described above, the data processing means is realized by the execution of step 200 in FIG. 2 by the CPU 4. Also,
The execution of step 300 in FIG. 2 by the CPU 4 and the drive circuit 8 realize an operation control means. Further, in the embodiment of the invention described above, the prestroke actuator 1 provided in the row type fuel injection pump is described as an example of the actuator that can set the condition value regarding the injection to a desired value, but is not limited thereto. Of course, there is no need to do this. For example, when the pre-stroke actuator 1 is provided in the row-type injection pump, an actuator (not shown) called a governor actuator for controlling the position of a link that normally performs a function of setting a fuel injection amount is also provided. The fuel injection amount can be controlled by controlling the operation of the governor actuator. The electrical configuration for controlling the operation of the governor actuator is basically the same as that shown in FIG. 1, and the electrical configuration of the digital servo IC is similar to that described for the pre-stroke actuator 1. It is possible to eliminate a control shift due to a variation in characteristics and to improve control accuracy.

[0022]

As described above, according to the present invention,
By adopting a configuration in which there is no deviation in control without adjusting the component constants in the conventional manufacturing process, adjustment of the component constants in the manufacturing process becomes unnecessary, and the so-called software processing Since the control deviation can be eliminated, the control accuracy can be improved with a relatively simple configuration. In addition, since individual variations in the electrical characteristics of electronic components (digital servo ICs) can be offset by so-called software processing, it is not necessary to adjust the so-called component constants in the manufacturing process for each product. This brings about an effect that control accuracy can be improved without increasing the price of the device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a configuration example of a fuel injection control device according to an embodiment of the present invention.

FIG. 2 is a subroutine flowchart showing a procedure of pre-stroke control by the fuel injection control device shown in FIG.

FIG. 3 is a characteristic diagram showing an example of input / output characteristics of a digital servo IC.

FIG. 4 is an explanatory diagram for explaining a difference in prestroke control between a case where a shift cancellation calculation process is performed and a case where a shift cancellation calculation process is not performed.

FIG. 5 is a configuration diagram showing one configuration example of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Actuator 2 ... Sensor 3 ... ECU 4 ... CPU 5 ... Digital servo IC 6 ... Digital servo IC peripheral circuit 7 ... Read-only memory 8 ... Drive circuit 9 ... Standard device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Koyama 3-13-26 Yaumicho, Higashimatsuyama-shi, Saitama Prefecture Bosch Automotive System Higashimatsuyama Plant (72) Inventor Haruo Yamakabe 3 Yayumicho, Higashimatsuyama-shi, Saitama −13−26 Bosch Automotive Systems Higashimatsu Yama Factory F-term (reference) 3G084 AA01 BA13 BA15 DA04 DA13 DA14 DA21 EA02 EA04 EA08 EC04 FA13 FA17 3G301 HA02 JA17 JA20 LB14 LC10 MA11 MA18 NA08 NA09 NB06 NB20 NC01 PB03ZPZZ

Claims (3)

[Claims] 1. A fuel injection control device configured to control an operation of an actuator provided in a fuel injection pump so that a condition value relating to injection can be set to a desired value. An operation amount detection unit for detecting, a digital data generation unit for converting an output signal of the operation amount detection unit into predetermined digital data and outputting the digital data, and inputting an output signal of the digital data generation unit and performing predetermined processing Data processing means for inputting an output signal of the data processing means, determining an operation state of the actuator, and driving the actuator in accordance with the determination result, The predetermined processing in the data processing means is such that an output value with respect to an input value of the digital data generation means is determined in advance. The fuel injection control apparatus, characterized in that to cancel the deviation of the input data so that up Reel. 2. A fuel injection control device configured to control an operation of an actuator provided in a fuel injection pump so that a condition value relating to injection can be set to a desired value. A sensor to be detected; a digital servo IC that converts an output signal of the sensor into predetermined digital data and outputs the digital data; a microcontroller; a driving circuit that drives the actuator in accordance with a control signal from the microcontroller; A memory in which a correction constant is stored in a readable manner.
The deviation of the output signal from the ideal value is canceled out using a correction constant stored in the memory by a predetermined arithmetic expression to obtain an ideal value, and the operating state of the actuator is determined using the calculated ideal value. And outputting a control signal to the drive circuit based on the result of the determination. 3. An injection amount or an operation amount of an actuator for adjusting an injection timing provided in a fuel injection pump is detected by a sensor, and the detection signal is converted into digital data by an IC and input to a microcontroller. ,
An actuator control method in a fuel injection control device that controls the operation of the actuator by executing the control program by the microcontroller, and enables adjustment of the injection amount or injection timing of the fuel injection pump, which occurs in the IC. The difference between the output signal of the IC and the ideal value is canceled out by an arithmetic processing in the microcontroller to obtain an ideal value, and the control program is executed using the ideal value. In the arithmetic processing, When a standard device having ideal output characteristics as a sensor instead of a sensor is connected to the IC, an output value obtained by the IC and the I value
An actuator control method, wherein a correction constant preset based on a deviation from an ideal output value of C is used.