JPS63195357A - Electronic control type fuel injection unit - Google Patents

Abstract

PURPOSE:To simplify the change of the control program, by determining whether the control program is written in an EPROM depending on the identification data or not at the starting of the control, and selecting either the execution of the control program or the writing. CONSTITUTION:A microcomputer 30 of a control unit 21 executes a necessary control operation by the control programs and the data in a ROM 32 and an EPROM 41. The EPROM 41 can write a desired control program by the microcomputer 30, and can erase all the contents by radiating an ultraviolet ray when a change is necessary. By operating the control unit 21, the microcomputer 30 takes a mode to write a control program to the EPROM 41, and by giving the data related to the desired control program to the microcomputer 30, the desired control program is stored in the EPROM 41. In such a way, the change of the control program can be executed simply without changing parts in the control unit which is incorporated to a fuel injection pump.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electronically controlled fuel injection device.

(Prior Art) In an electronically controlled fuel injection device for an internal combustion engine, an actuator is generally provided in the fuel injection pump body for operating required adjustment members such as a fuel adjustment member and/or an injection timing adjustment member. In this case, control calculations for the injection amount and/or injection timing are performed in a control unit provided separately from the pump body, and the control signal obtained as a result of the calculation is applied to the required actuator via a predetermined connection cable. The configuration is as follows. Therefore, calculations within the control unit must take into account mechanical variations in the fuel injection pump, and for this reason, compensating elements such as potentiometers or switches are provided within the control unit and are combined at that time. The correction element was adjusted for each fuel injection pump.

Therefore, whenever the control unit or fuel injection pump is replaced, the correction element must be adjusted each time.
There was a problem in that the cost for one maintenance inspection had to be high.

In order to improve the above-mentioned problems, for example, in a fuel injection device for a diesel engine, an adjustment element is built into the connector connected to the electric circuit on the pump side, and the adjustment element uses the control signal from the control unit to control the injection. A configuration has been proposed in which the adjustment is made according to the unique characteristics of the fuel injection pump, but in this configuration, the adjustment element is set according to the characteristics of the fuel injection pump, so even if the control unit is replaced, the adjustment element does not change. Although there is no need for readjustment, the adjustment element still needs to be readjusted if the injection pump is replaced.

In order to solve this problem, the applicant provided the fuel injection pump body with a memory in which data regarding the characteristics of the fuel injection pump are stored in advance and a calculation means for performing control calculations for controlling the fuel injection pump. As a result, even if the fuel injection pump is replaced, control i according to the control target value indicated by an external signal can be performed without adjustment.
proposed a fuel injection device capable of obtaining the amount of t (see Japanese Patent Laid-Open No. 1823/1983).

(Problem to be solved by the invention) However, in this proposed device, the control program
ROM in the control unit built into the fuel injection pump
For example, if the control program is improved, the fuel injection thread tube into which the old control program has been written will become unusable unless the program is changed.

By the way, in this type of device, in order to increase the packaging density of the control unit, small parts such as leadless chip carriers (LCC) are used as memory elements and other parts, but these nine types of small parts are Once attached to the board by soldering, it is not easy to remove, and therefore it is extremely difficult to convert the old memory element to a memory element with a new program, which can be used to control old fuel injection pumps. Changing a program requires a lot of effort and expense.

Therefore, it is an object of the present invention to provide an electronically controlled fuel injection system in which the control program can be easily changed without replacing parts of the control unit.

(Means for Solving the Problems) The content of the present invention for achieving the above object is an electronically controlled fuel injection device in which the operation of a fuel injection pump is controlled by a microcomputer according to a control program given in advance. a rewritable read-only memory for storing the control program; means for storing identification data indicating whether or not the control program is stored in the read-only memory; and means for storing the identification data at the start of control. The method is characterized in that it includes means for determining whether or not a control program is written in the read-only memory based on the above, and for selecting execution of the control program or writing of the control program according to the result. .

(Function) This device uses a rewritable read-only memory (hereinafter referred to as B) as a means for storing control programs.
Therefore, when the control program is improved, the stored control program can be erased by opening the erase window provided in the EPROM and irradiating it with ultraviolet light. and another control program I! Can be stored in FROM.

[Identification data indicating what state the EPROM is in is stored, and at the start of control, it is determined whether or not a control program has been written in the tiPROM based on this identification data, and the result is Depending on the situation, a selection is made whether to write the control program into the EPROM or to execute the stored control program.

(Example) Hereinafter, the present invention will be explained in detail with reference to illustrated embodiments.

FIG. 1 shows a configuration diagram of an embodiment of an electronically controlled fuel injection device according to the present invention.

The fuel injection device 11 includes a fuel injection pump 13 that is driven by rotational output from a diesel engine 12 to inject and supply fuel to the diesel engine 12, and an external control for calculating control data to be applied to the fuel injection pump 13. Unit 14 and tJt are listed.

The fuel injection pump 13 includes a plunger 18 that reciprocates within a plunger barrel 17 according to rotation of an input shaft 16 connected to the diesel engine 12, and a plunger barrel 17.
Boat 1 with passages 19 for fuel intake/discharge formed in the boat 1
After the fuel is sucked through the passage 19, the solenoid valve 20 is closed at a predetermined timing while the plunger 18 is rising, thereby compressing and delivering the sucked fuel. Injection from pulp (not shown) is started, and fuel injection is ended by opening the electromagnetic valve 20. That is, the injection advance angle (injection timing) can be controlled by controlling the timing of closing the solenoid valve 20, and the injection amount can be controlled by controlling the time from when the solenoid valve 20 is closed until it is opened. It is configured so that it can be done. The opening/closing control of the solenoid valve 20 is performed by the fuel injection pump 1
This is carried out as described below by the internal control unit 21, which is expected to be located within 3.

The external control unit 14 controls the diesel engine 12
It outputs data D+ and Dg indicating the required injection amount Qt and injection advance value θ to the diesel engine 12 at that time, respectively, according to various data indicating the operating state of the engine at the time. Accelerator data A indicating the operation amount (not shown) and pressure data P indicating the boost pressure are outputted from the accelerator sensor 22 and the boost pressure sensor 23. Furthermore, a top dead center pulse TDC is output from the top dead center sensor 24 attached to the crankshaft 12a of the diesel engine 12 every time the piston (not shown) of the diesel engine 12 reaches the top dead center position. This top dead center pulse TDC is input to the external control unit 14 and the internal control units 2 and 1.

The external control unit 14 is configured using a microcomputer, stores required governor characteristics and timer characteristics as data, calculates the engine speed at any given time based on the above-mentioned top dead center pulse TDC, Based on the calculated engine speed and input data A, P, the target injection amount Q1 and target injection advance value θ are calculated at each time, and the data D, Dt indicating the results are internally transmitted via the common line 25. It is sent to the control unit 21.

The internal control unit 21 is also configured using a microcomputer, and the data D, Dg
In addition, the top dead center pulse TDC, the rotation pulse N from the rotation sensor 26, the lift timing pulse LP from the needle lift sensor 27 for detecting the needle lift timing of the injection valve (not shown), and the temperature of the fuel. Fuel temperature data FT from the fuel temperature sensor 28 that detects the fuel temperature is input to the internal control unit 21.

FIG. 2 shows a block diagram showing the configuration of the internal control unit 21. As shown in FIG. The internal control unit 21 includes a 1-chip microcomputer 30 and an EFROM 41 which is a rewritable read-only memory that serves as an external memory for the 1-chip microcomputer 30.
It is equipped with.

The l-chip microcomputer 30 includes a central processing unit (CPU) 31 and a read-only memory (ROM) 32.
and a random access memory (RAM) 33, which are connected by a bus 34.

The bus 34 is further connected to ports P0 to P, and these ports P0 to P3 are configured to receive switching control signals for boat switching control output from the CPU 31 via a control line 35. It has become. therefore,
The connection state between each boat and the bus 34 is controlled according to the switching control signal. In the illustrated embodiment, boats Po to P
Data and corresponding address data are assigned to P2, and a read control signal (2) and a write control signal WR are output from P3. Reference numeral 36 indicates a signal control section, which controls the timing signal ALE.
and PSII! Output N.

The RAM 33 is connected to the ROM 32 and CP[I
31, and ROM32 and statement are connected to EFROM.
Based on the control program and data stored in 41, necessary control calculations are executed.

The serial port 37 in the CPU 31 is an input/output device (
Ilo) 47, top dead center pulse TDC,
In addition to the rotation pulse N, lift timing pulse LP, and fuel temperature data FT, serial data Ds and transfer command signal TD, which will be described later, are also supplied to the serial boat 37 via the input/output device 47.

The EFROM 41 is provided to store a control program for combustion control executed by the CPU 31, and the ROM 32 stores a control program for writing a required control program into the BFROM 41. ing. Therefore, the CPU 31 is a ROM
EPRO according to the program stored in 32
Write the required program in M41 or EFRO
Control is performed in accordance with a control program already written in M41.

In order to enable the CPU 31 to identify whether or not a control program is written in the EFROM 41, the EFROM
When the control program is written in the ROM 41, the predetermined code identification data D4 is written in the EPROM 41.
It is configured to be stored at a predetermined address M within 1.

FIG. 3 shows a flowchart showing the programs stored in the ROM 32. This program runs in response to the device being powered on, and
First, in step 51, the contents of the address M of the EFROM 41 are read, and it is determined whether the contents match a predetermined code. i: When the control program is stored in pRoMA, a predetermined code ((00) in the illustrated embodiment) is stored at the address M at the same time as the control program is stored. The determination result is YES, and the process advances to step 52, where the control program stored in the EFROM 41 is executed by the CPU 31.

Once execution of the control program in the CPU 31 is started, the microcomputer 30 thereafter performs control according to this control program until the power of the device is turned off.

In order to erase the contents of the EFROM 41, when ultraviolet rays are irradiated inside the EFROM 41 from the erase window as described later, the contents stored at the address M are also erased at the same time, and the contents of the address M become (F F). If so, the determination result in step 51 is NO, and the process proceeds to step 53. In step 53, the contents of the control program input from the outside are once input to the CPU 31, and then stored in the UPROM 41. The control program is stored (step 54). When the storage of the control program is completed, the process proceeds to step 55, where:
It is determined whether or not the storage of the control program has been completed. If the determination result is No, the process returns to step 53 and writing of the control program to the EFROM 41 is continued. When the storage of the control program is completed in this way, the determination result in step 55 becomes YES.
The program proceeds to step 56, where a predetermined code (00) is stored at address M of the EFROM 41, and the execution of this program ends.

Next, a configuration in which control program data received by the CPU 31 via the input/output device 47 is stored in the EPROM 41 by the microcomputer 30 will be described with reference to FIG.

The data to be written to the EFROM 41 and the address of the BFROM 41 to which the data should be written are sent to the cPU 31 as serial data D via the input/output device 47.
This serial data D is received by CP[I 31.

In this case, in the microcomputer 30, a predetermined write program (see FIG. 3) for writing to the BFROM 41 stored in the internal ROM 32 is being executed, so the bauds 1-po to P3 are It is in a state where it can be used as a general-purpose input/output boat.

Address data AD is received as 16-bit data from A to All, and its lower 8 bits of lower address data AL (AO to A?) are written to port Po. Data A
U (As = A+s) is written to port P2, and the contents of this data A@~AI5 are decoded by the decoder 42 connected to boat Pg, and f! FROM 4
1 is selected, the decoder 42
The level of the output line 42a of EFRO becomes a predetermined state, and EFRO
M41 is selected.

A latch circuit 43 is connected to baud) Pa. A latch signal L indicating the latch timing of this latch circuit 43
In order to output S, an AND circuit 44 is provided which responds to a timing signal ALE output from the signal control section 36 and a read control signal RD for setting an external memory (not shown) to a read mode. Only when the level of the read control signal RD is rHJ and the level of the timing signal ALE is also rHJ, the output level of the AND circuit 44 becomes rHJ,
Lower address data AL(
Ao to Ay) are latched by the latch circuit 43, and [EFR
Applied to address terminal X of OM 41.

After the lower address data AL is launched into the launch circuit 43, the level of the read control signal 100 is set to rLJ. As a result, the level of the latch signal LS becomes rLJ, and henceforth, even if the contents of baud)Pa are changed, the contents of the data launched into the latch circuit 43 will not be changed. This means that the addressing of the data to be written into the EFROM 41 has been completed.

Then write the data to be written to EFROM 41 (baud)
When data is written to Po, the data written to port Pa is applied to data terminal Y of EPROM 41 via data line 46. As already explained, in this case terminal Y
Data indicating the address to write the data given to is given to the terminal X by the latch circuit 43.

Thereafter, the level of the write control signal WR output from the boat P3 is set to "L" for a predetermined period of time. Therefore, the output level of the AO circuit 45 responsive to the read control signal RD and the write control signal WR is becomes rLJ for a predetermined time. Since the output of the OR circuit 45 is applied to the terminal of the EFROM 41, the II!FROM 41 is in the write mode only when its output level is rLJO, and the predetermined write voltage V supplied to the EFROM 41 at this time is □
As a result, the required data applied to the terminal Y is stored at the required address according to the data applied to the terminal X. When the writing of data to the HFROM 41 is completed in this way, each level of the read control signal RD and the write control signal WR is set to rHJ, and the device 21 writes the EP
The ROM 4 L is returned to the state before the start of the data write operation.

Next, a case will be described in which the data stored in the EFROM 41 as described above is read out and stored in the RAM 33. In this case, when predetermined transfer command data TD for a data transfer command is input to the CPt 131 via the input/output device 47, the CPU 31 determines the address of the data to be transferred according to the contents of the transfer command data TD. Send data TA to bus 34. In this case as well, the upper 8 bits (upper data TAU) of the data TA are output from the port Pg, and the lower 8 bits (lower data TAL) are output from the port po. Then, as in the case of writing, the upper data TAU is decoded by the decoder 42 and the EFROM 41 is selected, and the lower data TAL is latched by the latch circuit 43 that operates in response to the timing signal ALE, and the lower data TAL is latched to the terminal X. applied. When the addressing for reading data from the EFROM 41 is completed in this way, the level of the signal PSEH becomes rLJ, a "L" level signal is supplied to the DE terminal of the EPROM 41, and the EFROM 41 enters the read mode. . As a result, the data stored in the EFROM 41 at the address designated as described above is read from the terminal Y and input to the port P0 via the data line 46. The data input to boat Pa is
It is transferred to RAM 33 via bus 34 and stored.

4(al) to FIG. 4(e) show timing charts when external data is stored in the EFROM 41.In response to the reception of serial data D, at time 1-1 Upper and lower address designation blocks AU and AL are output at . (Figure 4 (a), (b))
, After L, 1=1. When the timing signal set 1- and the read signal RD both become rHJ, the level of the latch signal LS becomes r)(J and 1=13
When the level becomes rLJ, the contents of the lower address data AL are latched in the launch circuit 43, so that after 1=1°, the contents of the data supplied to the terminal X become the lower address data AL. When the level of terminal `` becomes rLJ at 1=14, the EPROM
Data D to be stored in port 41 appears at port P0.

As a result, data D is applied to terminal Y of EPROM 41, and data D is stored at the address indicated by data AL and AU for addressing.

Figure 5 (al to Figure 5 (el) shows the EFROM 41
A timing chart showing the operation when transferring data stored in the memory to the RAM 33 is shown.

In response to the input of transfer command data TA, upper and lower address data TAt1 . TAL is output (Fig. 3 (a), (b)), and after L, t=
At t', □, both the timing signal ALE and the read control signal RD become rHJ level, so that the level of the latch signal LS becomes rHJ, and then 1=1.
3, when the level becomes "L", the contents of the lower data TAL are latched into the launch circuit 43. Therefore, 1 = 1, . . . From then on, the content of the data supplied to the terminal X becomes the lower data TAL. When the level of the terminal PSEN becomes rLJ at 1==1.4, the data DT applied to the port P0 is sent to the RAM 33. As a result, the desired store data stored at the address indicated by data TA[J, TAL is
The data is transferred from the PROM 41 to the RAM 33.

In this way, by providing desired data from the outside in the form of serial data to the microcomputer 30, E
In addition to being able to store the data in FROM 41, the data stored in EPROM 41 can be transferred to RAM 33 in microcomputer 30.

The control program written in the EFROM 41 in this manner can be easily erased by irradiating the interior of the IEFROM 41 with ultraviolet light through the erasing window of the IEFROM 41.

6 and 7 show a configuration for easily erasing data stored in the EPROM 41 soldered to the board in the internal control unit 21 from outside the fuel injection pump 13. has been done. 6th
As can be seen from the figure and FIG. 7, the printed circuit board PB of the internal control unit 21 is fixed on the casing 15 of the fuel injection pump 13,
is covered with a metal cover 61, and this cover 61
A window 62 is provided in a portion of the EFROM 41 facing the erasing window 41a, and the window 62 and the erasing window 41a are connected to each other.
An optical path is formed by a glass plate 63 between the window 62 and the window 62.
3 to enter the erasing window 41a of the EPROM 41, and all data stored in the EFROM 41 can be erased.

Reference numeral 64 indicates a light-shielding lid member, and normally, this light-shielding lid member 64 is screwed to the cover 61 to close the window 62 and prevent light from entering the EPROM 41 from the outside. It has become.

According to the above configuration, a desired control program can be written into the EFROM 41 by the microcomputer 30. If you want to change this control program, you can apply ultraviolet light through the window 62.
1, thereby erasing all the contents of the EFROM 41 and operating the device. Since the contents of the address M of the EFROM 41 are (FF), the microcomputer 30 instructs the control program to the CPROM 41. This is the mode for writing. Therefore, by providing data regarding a desired control program to the microcomputer 30 from the outside, the microcomputer 30 can store the desired control program in the EFROM 41.

Therefore, even if the control program needs to be changed due to a control program version update, it is extremely easy to handle the situation, and even if it is an old model fuel injection pump, it can be replaced with a new model without removing any parts. It is extremely economical because it can be used as

In this case, parts of the control program that will not be changed may be stored in the ROM 32, and parts that may be changed may be stored in the EFROM 41.

(Effects) According to the present invention, as described above, it is possible to extremely easily change the control program without replacing parts in the control unit incorporated in the fuel injection pump. Even if there is a change in the control program, the control unit will not become unusable, making it extremely economical.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the fuel injection device according to the present invention, Fig. 2 is a block diagram showing the structure of the internal control unit shown in Fig. 1, and Fig. 3 is a block diagram showing the structure of the internal control unit shown in Fig. 2. Flowchart showing programs stored in the fourth
Figures (a) to 4 (el) and Figures 5 (a) to 5 (Q) are time charts for explaining the operation of the circuit shown in Figure 2, and Figure 6 shows the internal control unit. FIG. 7 is a partially sectional front view of the fuel injection pump showing a state in which it is attached to the fuel injection pump, and FIG. 7 is a plan view of the fuel injection pump shown in FIG. 6. 11...Fuel injection device, 14. ... external control unit), 21 ... internal control unit, 30
...Microcomputer, 32...Read-only memory (ROM), 41...Writable read-only memory (EFROM).

Claims (1)

[Claims] 1. An electronically controlled fuel injection device in which the operation of a fuel injection pump is controlled by a microcomputer according to a control program given in advance, comprising: a rewritable read-only memory for storing the control program; means for storing identification data indicating whether or not a control program is stored in the read-only memory, and determining whether or not a control program is written in the read-only memory based on the identification data at the start of control; 1. An electronically controlled fuel injection device comprising: means for selecting execution of a control program or writing of a control program according to the control program.