JPH0310962B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises means for inputting variables representing the state of a controlled object, and memory means comprising a table storing control data predetermined according to the respective values of the variables. , relates to a table lookup type control device comprising means for looking up a table in accordance with an input variable and reading control data corresponding to the variable; and means for determining a control amount based on the read control data. It is.

Control devices using such a table lookup method are known and used for various purposes. In conventional control devices like this, computer control is performed, so the data length of one unit of data extracted when looking up a table is fixed, and one unit of data is included in it. ing. For example, when using an 8-bit processor, one word made up of 8 bits represents one control data, and one control data can be read by one table lookup routine. It's summery. However, in such a control device, when performing multiple controls on one input variable, a table lookup subroutine is called and executed, which requires a long calculation time equal to the number of types of control data. This has the drawback that it takes time to read out the desired control data. Furthermore, the amount of control data increases, it is necessary to use a large-capacity memory, and the device becomes larger and more expensive. One application of a control device based on the table pull-up method is to control the drive of an automobile's internal combustion engine. It is necessary to process many types of control data, and as mentioned above, the disadvantages of table lookup taking time and memory capacity becoming large become more noticeable.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art,
Desired control data can be read out in a short time,
Furthermore, the present invention aims to provide a control device using a table-backup method that can reduce memory capacity.

A control device using a table pickup method according to the present invention includes two or more types of actuators, a detection means for detecting a predetermined control parameter common to these two or more types of actuators, and a detection unit configured based on the control parameter. memory means for configuring a lookup table by storing two or more types of control data in one unit area having a fixed data length; and the two or more types of control data corresponding to the control parameters detected by the detection means. reading means for simultaneously reading control data from the lookup table; data dividing means for dividing the two or more types of control data read out for each type of control data; and control means for controlling the actuator based on the control data divided by the data division means.

According to the control device of the present invention, a plurality of pieces of control data can be obtained by executing the table lookup subroutine once, so the time to read the control data is significantly shortened, and one unit of data is fixed data. Even though it has a long memory capacity, it requires less memory capacity. The present invention has been made based on the fact that, for example, in the control of the internal combustion engine mentioned above, a plurality of control data are determined for the same control parameter, so these can be included in one unit of data. This situation occurs not only in the control of internal combustion engines, but also in many other controls.

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing the overall structure of a control device for an internal combustion engine, which includes a control device using the table pickup method of the present invention. An intake pipe negative pressure sensor 2 and a crank angle sensor 3 are provided to detect the operating state of the internal combustion engine, that is, the engine 1. The output signal of the intake pipe negative pressure sensor 2 represents the engine load, and the output signal of the crank angle sensor 3 represents the engine rotation speed, and various control data are read out using these two pieces of information as variables (control parameters). shall be taken as a thing. The output signals of these sensors 2 and 3 are input to input devices 4 and 5, respectively.
The signal is supplied to the central processing circuit 6 via the . A memory device 7 is connected to the central processing circuit 6, and this memory device 7 is provided with a table storing control data determined in advance according to input variables, and desired control can be performed by looking up this table. Read data. For example, in controlling engine 1,
Depending on the intake pipe negative pressure and engine speed mentioned above, the ignition advance value (hereinafter abbreviated as ADV), exhaust gas recirculation rate (hereinafter abbreviated as EGR), and fuel injection amount (EGI)
(abbreviated as KMR), air-fuel ratio, fuel increase rate (abbreviated as KMR), etc. are stored in a table in the memory device 7. In conventional tables, only one type of control data is stored in one unit of data, for example, one word consisting of 8 bits, which can be extracted by one lookup. In contrast, in the present invention, a plurality of pieces of control data are inserted into one unit of data extracted by one table lookup. FIGS. 2a and 2b show one unit of a conventional table, and in this example, one word is composed of 8 bits. Figure 2a shows one unit of ADV data looked up based on the input rotational speed N ₀ and intake pipe negative pressure P ₀ .
Control data of $1A=26 in hexadecimal is stored. Further, FIG. 2b shows one unit of EGR control data looked up at the same rotational speed N ₀ and intake pipe negative pressure P ₀ , and represents $06=6 in hexadecimal. In the past, in order to obtain such control data for ADV and EGR, it was necessary to perform table lookups at least twice. This table lookup subroutine generally takes a long time, so it is difficult to execute it twice. On the other hand, in the present invention, as shown in FIG.
ADV control data and EGR control data are inserted into one word. A plurality of control data thus read out are taken into the central processing circuit 6 and subjected to appropriate arithmetic processing to determine the control amount. ADV
The control amount related to EGR is supplied to the igniter 9 via the output device 8 to control the ignition timing.
The control amount related to the exhaust gas recirculation rate is supplied to the EGR modulator 11 via the output device 10 to control the exhaust gas recirculation rate.

Figure 4 shows the engine speed RPM on the horizontal axis.
The vertical axis represents the intake pipe negative pressure P, and the rotational speed N ₁ , N ₂ ...
This is a graphical representation of control data, such as ADV data, at the intersection of N _o and intake pipe negative pressures P ₁ , P ₂ . . . P _o . Since the actual input variables N ₀ , P ₀ usually do not match the set values N ₁ , N ₂ ...N _o , P ₁ , P ₂ ...P _o , when calculating the actual control amount, Interpolation is performed as described below.

FIG. 5 is a flowchart showing a routine for determining the control amount by such interpolation, and each step is indicated by a block numbered 31 to 38. After the start, the rotation speed is used as a human variable.
Read N ₀ and intake pipe negative pressure P ₀ . Next, the grid point N ₆ is larger than N ₀ , the grid point N ₅ is smaller than N ₀ , the grid point P ₄ is larger than P ₀ , and the grid point is smaller than P ₀ .
Find P ₃ . Next, perform a table search and select the four grid points (N ₆ , P ₄ ), (N ₆ , P ₃ ),
Read control data at (N ₅ , P ₄ ) and (N ₅ , P ₃ ). In the present invention, at each grid point
Since control data regarding ADV and EGR can be obtained at the same time, we need to divide them into grid points,
The control amount of the ADV at N ₀ and P ₀ is determined by interpolation from the control data regarding the ADV of , .
Next, the EGR at N ₀ , P ₀ is determined by interpolation from the control data regarding the EGR of the grid points, , and .
Find the control amount. Next, the EGR modulator 11 controls the igniter 9 based on the control amount of the ADV, sets the ignition advance value to a predetermined value, and further drives the exhaust recirculation control valve based on the control amount related to EGR.
is controlled to perform exhaust gas recirculation at a predetermined rate. In this way, according to this example, by executing the table search subroutine one time,
ADV control amount and EGR control amount can be obtained, processing capacity is significantly improved, and memory capacity can be reduced. On the other hand, in order to obtain a similar control amount with a conventional control device, steps 31 to 33 are very time-consuming as shown in FIG.
must be repeated twice, resulting in a greater response delay than in the present invention.

FIG. 7 is a diagram showing another example of the storage format of control data in the control device of the present invention. In this example, we use a 16-pit processor and convert 2 bytes into 1
This is a case where it can be processed as a word. ADV control data consists of 6 bits and 3 bits
EGR control data, three types of multi-step signals representing the EGI pulse width (injector pulse width) consisting of 6 bits, and a 1-bit on/off signal representing whether air-fuel ratio control should be performed or clamped. are inserted in one word.

Figure 8 shows yet another example of the 1-word format; in this example, 8-bit ADV is used.
Control data for the 8-bit injector pulse width and control bits representing the 8-bit injector pulse width are inserted into one word. In this way, a 16-bit processor can handle data in 2 bytes and 1 word, so 2 ¹⁶
= 650,000 steps of resolution can be effectively used, and multiple types of control data can be stored in one word. In addition to the examples described above, the following combinations of control data can be inserted into one word. EGI pulse width control data and air-fuel ratio control data, control data for basic ignition advance value and control data regarding the change limit due to variable components, control data for basic ignition advance value and limit control data for retard amount by knock control, or Control data of the limit value as a result of retardation, control data of the basic control output value of EGR control,
Control data for the control target value of the EGR sensor, control data for the EGI pulse width, control data for determining whether to cancel air-fuel ratio control, control data for the basic ignition advance value, and variable control of the ignition advance (for example, when In order to carry out such various controls, it is necessary to provide sensors in addition to the crank angle sensor 2 and intake pipe negative pressure sensor 3 shown in Fig. 1. These sensors are easily available; for example, in order to control the air-fuel ratio, an O ₂ sensor may be provided. The igniter 9 shown in FIG. 1 can also be used as a device that performs control based on the determined control amount.
In addition to the EGR modulator 11, a drive device such as a fuel supply amount control device may be provided.

As described above, in the present invention, multiple pieces of control data are inserted into one word or one byte, so in the case of a multi-stage control signal, the number of stages (resolution) decreases, but as described above, the control amount can be reduced by interpolation processing. can be determined, so there is almost no decrease in accuracy compared to the conventional method. On the contrary, in the present invention, the control response delay is considerably shorter than that of the conventional method, so that the overall control accuracy can be improved.

As described above, according to the control device of the present invention,
1 with fixed data length of lookup table
A plurality of control data corresponding to a common control parameter for multiple actuators is stored in a word or one byte, and after reading these multiple control data simultaneously according to the detected control parameter, multiple control data is stored. Since the control data is broken down into data and each actuator is controlled using each control data, the number of executions of the time-consuming table lookup subroutine can be reduced, and the desired control data can be obtained in a short time. As a result, the control response delay can be extremely shortened, and the required amount of data memory can be reduced, resulting in a simpler configuration and lower cost. Furthermore, since control parameters can be detected in common, the configuration can be simplified in this respect as well.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an example of a control device using the table-up method of the present invention, FIGS. 2a and b are diagrams showing the format of one word of control data in a conventional control device, and FIG.
The figure is a diagram showing the format of one word of control data in the present invention, Figure 4 is a diagram to explain the interpolation process of control data, and Figure 5 is a diagram showing the sequential steps of the interpolation process in the apparatus of the present invention. FIG. 6 is a flowchart showing the sequential steps of interpolation processing in a conventional device, and FIG.
8 and 8 are diagrams showing a modification of the format of one word of control data in the present invention. 1...Engine, 2...Crank angle sensor, 3
...Intake pipe negative pressure sensor, 4, 5...Input device,
6...Central processing circuit, 7...Memory device, 8,1
0...Output device, 9...Igniter, 11...
EGR modulator.

Claims (1)

[Claims] 1. Two or more types of actuators, a detection means for detecting predetermined control parameters common to these two or more types of actuators, and two or more types of actuators determined based on the control parameters. memory means for storing control data in one unit area having a fixed data length to form a lookup table; reading means for simultaneously reading from the lookup table; data dividing means for dividing the two or more types of control data read out for each type of control data; and an independent actuator for each type of control data. 1. A control device using a table pickup method, comprising: control means for performing control based on control data divided by data division means.