JPH041450A - Electronic control fuel injector - Google Patents

Abstract

PURPOSE:To improve the extent of startability as well as to keep off any malfunction and runaway in a central processing unit by detecting a time lag of supply voltage, while splitting and checking the contents of a read-only memory when the detected voltage is more than the specified value, by way of example, and simultaneously performing the fuel injection control. CONSTITUTION:Programs and various data of a central processing unit 33 are stored in a read-only memory 31. On the other hand, at a supply voltage monitoring means 32, supply voltage E of a car mounted battery or the like is monitored in a time-lagging manner, and whether the detected voltage ED is more than the specified value E1h or less than this specified value E1h is detected. The central processing unit 33 is operated by the supply voltage E, and when the detected voltage ED is less than the specified value E1h, or the last time check is more than that, the contents of the read-only memory 31 are all checked, and when the detected voltage ED is more than the specified value E1h, or the last time check is normal, the contents of the ROM 31 are split and checked, while fuel injection control is performed by a program or the like stored in this ROM 31.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electronic fuel injection device used in automobiles and the like.

Conventional technology Generally speaking, electronic fuel injection devices used in automobiles, etc. are equipped with a microcomputer (CPU) that detects the engine condition and controls fuel injection time, and a one-liner computer that stores the CPU's execution programs and various control data. (ROM)
etc., and the CPU checks whether the contents of the ROM are normal.

Conventionally, in a method for checking the contents of this type of ROM, as shown in FIG.
All contents are checked, and if normal, proceed from step 2 to step 3 for initial setting, and in step 4, fuel injection control is performed. On the other hand, if the condition is not normal, the process branches from step 2 to step 5, and a warning and corrective action are performed.

Another method, as shown in FIG. 5(B), is to enter the fuel injection control state (step 12) after initial setting (step 11), and then enter the control loop (steps 12→13→14→1).
In 2), R is adjusted so as not to interfere with fuel injection control.
Divide and check the OM contents (Step 13), and if not normal, issue an alarm and take corrective action (Step 15)
method is known.

In addition, as another method, as shown in FIG. 5(C),
First, check all the contents of the ROM (Step 21)
, if it is not normal, an alarm is issued and a corrective action is performed (steps 22→23); on the other hand, if it is normal, after the initial settings (
Step 22 → 241) Enter the fuel injection control state (Step 25), and control loop (Step 25 → 26 → 27 →
In step 25), the contents of the ROM are divided and checked in step 26), and if it is not normal, a warning is issued and a corrective action is taken (steps 27→28).

Problems to be Solved by the Invention However, as shown in FIG. There is a problem that injection control is delayed and normal control cannot be performed.

On the other hand, as shown in FIG. 5(B), during fuel injection control, RO
The method of dividing and checking the contents of M can solve the above problems and discover abnormalities during operation, but it requires only one loop (steps 12 → 13 → 14).
→12) Since the time that can be checked is limited, it is necessary to divide the check area, and therefore there is a problem that the abnormality detection time is delayed and there is a risk of malfunction or runaway.

In addition, as shown in FIG. 5(C), the method of checking the entire contents of the OM before control and dividing it into parts during control is step 21 as in FIG. 5(A). There is a problem in that control is delayed by the time required to check.

Here, to explain the starting point of the CPU that performs the above fuel injection control, the power supply voltage is periodically increased to 10" because the supply capacity of the on-board battery that is the power source is low, and a large current flows through the starter motor at the time of starting. (2) The CPU is reset and restarted.

Further, as shown in FIG. 6, the power supply voltage varies depending on the load when rotating the engine, and this variation is synchronized with a TDC signal (top dead center detection signal) indicating the fuel injection timing. Then, due to voltage drop due to cranking etc., CP
After U is reset and restarted, if fuel injection is not possible within the time interval TINTO until the TDC signal, fuel injection cannot be performed. Therefore, if the time interval TINT is set longer, startability will deteriorate.

Therefore, the method of checking the entire contents of the ROM before fuel injection control as shown in FIGS. 5(A) and 5(C) has the problem that starting performance deteriorates when the power supply voltage decreases.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a fuel injection device that can improve startability and prevent malfunctions and runaways of the central processing unit.

Means for Solving the Problems In order to solve the above problems, the present invention detects the power supply voltage with a time delay, detects whether the detected voltage is equal to or higher than a predetermined value, and detects whether the detected voltage is equal to or higher than the predetermined value. If the detected voltage is less than a predetermined value, the entire contents of the read-only memory are checked, and if the detected voltage is less than a predetermined value, the contents of the read-only memory are divided and checked and fuel injection control is performed.

According to the above-mentioned structure, when the central processing unit starts when the ignition key of the car is turned on, the detected voltage of the power supply voltage is less than a predetermined value, and in this case, the contents of the read-only memory are read. Since everything is checked, malfunctions and runaways of the central processing unit can be prevented.

On the other hand, if the central processing unit is reset and restarted due to cranking while driving, the detected voltage of the power supply voltage is higher than a predetermined value, and in this case, the contents of the read-only memory are divided and checked. Therefore, starting performance can be improved.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic block diagram showing an embodiment of an electronic fuel injection device according to the present invention, and FIG. 2 is an embodiment of an engine control unit (ECU) equipped with an electronic fuel injection device according to the present invention. An illustrative block diagram, FIG. 3(A), is a detailed circuit diagram of the power supply voltage monitoring circuit of FIG. 2, FIG. 3(B) (C
) is an explanatory diagram of the operation of the power supply voltage monitoring circuit shown in Figure 3, and Figure 4.
This figure is a flowchart for explaining the operation of the ECLi of FIG. 2, particularly the CPU.

In FIG. 1, reference numeral 31 denotes a central processing unit 33 where programs and various data are stored.
M), 32 is the power supply voltage E of the vehicle battery (not shown), etc.
is monitored with a time delay, and the detected voltage ED reaches a predetermined value E.
This is a power supply voltage monitoring means that detects whether the voltage is equal to or higher than th or lower than a predetermined value E+h.

33 is operated by the power supply voltage E, and checks all the contents of the ROM 31 when the detection voltage ED is less than a predetermined value Eth, or when the previous check is above, and when the detection voltage ED is greater than or equal to the predetermined value E+h, Alternatively, it is a central processing unit that divides and checks the contents of the ROM 31 if the previous check was normal, and performs fuel injection control based on a program stored in the ROM 31.

In FIG. 2, 41 is a power supply voltage monitoring circuit that monitors the voltage of the vehicle battery, which is a power source, with a time delay, and 42 is a selection of various analog signals that detect the engine condition and the detection signal of the power supply voltage monitoring circuit 41. The multiplexer (MPX) 43 that outputs digital signals is an A/D converter that converts the output signal of the multiplexer 42 into a digital signal.

The engine 44 checks the programs stored in the ROM 45 as described later, and calculates the optimal fuel injection time from the engine condition in synchronization with the TDC signal (top dead center detection signal) that indicates the fuel injection timing. a central processing unit (CPU) that controls the solenoid drive circuit 50;
5 is a read-only 2-nomo that stores the execution program of the CPU 44 and various data (coefficients, etc.) for calculating the optimal fuel injection time! J (ROM), 46a is a RAM (random access memory) in which various input data etc. are stored, and 46b is a non-volatile memory having an area in which a flag is set when the CPU 44 checks the contents of the ROM 45 and is normal. It is a standby (RAM).

Further, 47 is a self-diagnosis device such as a watchdog timer for monitoring whether the operation of the CPU 4.4 is normal or not;
8 is a backup fuel injection circuit that calculates a simple fuel injection time independently of the CMJ 44; 49 is a CPU 44;
detects an abnormality in the ROM 45 or when the self-diagnosis device 47 detects an abnormal operation in the CPU 44.
50 is a switching circuit that switches the output of L144 to the output of backup fuel injection circuit 48; 52 is a solenoid drive circuit that drives the solenoid of electromagnetic injection valve (INJ) 51 according to the output of CPL 144 or backup fuel injection circuit 48; This is an alarm device that warns of abnormal operation of the CPU 44, etc.

Next, the power supply voltage monitoring circuit 41 will be explained with reference to FIG.

As shown in FIG. 3(A), the power supply voltage monitoring circuit 41 is a time constant circuit consisting of resistors r1, r2, r3 and a capacitor C, and the output terminal of the resistor r3 is connected to the multiplexer 42.
is connected to the input terminal AII of.

Due to its time constant τ, the voltage at the input terminal AIR of the multiplexer 42 becomes equal to or higher than the voltage reference value ADVRF after a time interval tl when the power is turned on, as shown in FIG. 3 (I3), and on the other hand, when the power is turned off, As shown in FIG. 3(C), the voltage becomes equal to or less than the voltage determination value ADVRF after the time interval t2.

Therefore, the car's ignition key is turned on and the C
When the PU44 starts, the output voltage of the old power supply voltage monitoring means is below the voltage judgment value ADVRF, and on the other hand,
When the CPU 44 is reset and restarted due to cranking while driving, the power supply voltage monitoring circuit 41
The output voltage becomes equal to or higher than the voltage determination value ADVRF.

Next, the operation of the CPU 44 will be explained with reference to FIG. As described above, the CPU 44 is reset and started when the power is turned on or the power supply voltage drops.

After the CPU 44 starts, in step 61, the output voltage of the power supply voltage monitoring circuit 41 is set to the voltage judgment value ADVRF.
It is determined whether or not the above is true, and if YES, the process branches to step 62, and if No, the process proceeds to step 63.

In step 62, the standby RAM, 45
It is determined whether the flag b is "1" or not. If YES, the process proceeds to step 67; if NO, the process branches to step 63.

In step 63, all data in the ROM 45 is checked, and if it is not normal, the process branches to step 65 and the flag in the standby RAM 46b is reset to "0".
In the following step 66, the alarm device 52 is activated, and the switching circuit 49 is switched from the CPU 44 to the backup fuel injection circuit 48 to perform a corrective action.

On the other hand, in the step 5 knob 67, the standby RAM 46
After setting the flag b to "1" and initializing it (step 68), the solenoid drive circuit 50 is controlled to perform fuel injection by the electromagnetic injection valve 51 (step 69).

Next, in step 70, the data in the ROM 45 is divided and checked, and if it is normal, the process returns from step 71 to step 69, and the normal amount control (step 69) and check (step 70) are repeated.

In step 71, if the data in the ROM 45 is not normal, the process advances to step 72, and the data in the standby RAM 45 is
The flag of b is reset to "o" t~, and in the following step 73, the alarm device 52 is driven (1), and the switching circuit 49 switches from the CPU 44 to the backup fuel injection circuit 48 to perform a corrective operation.

That is, according to the above embodiment, when the power is turned on by the ignition key and the CPL 144 makes a star 1, the output voltage of the power supply voltage monitoring circuit 1 reaches the voltage judgment value ADVRF as shown in FIG. 3(B). Since the following is true, all data in the ROM 45 is checked as shown in step 63.

On the other hand, if the power supply is momentarily turned off or the power supply voltage drops during operation, it will be reset and restarted, and if the power supply voltage is restored within the time interval 12, the power supply voltage monitoring circuit 41 at the time of restoration. Since the output voltage of is equal to or higher than the voltage judgment value ADVRF, the process branches from step 61 to step 62, and if the previous check was normal (flag = "1"), the control loop continues without performing the check in step 63. (Steps 69→70→71→69), and on the other hand, if the previous check was not normal (flag=rOJ), the control loop is entered after performing the check in Step 63.

Therefore, the power may turn off momentarily during operation, or
When the power supply voltage drops and the power supply voltage returns within the time interval 12, it is possible to enter the control state earlier, which improves the startability.On the other hand, when the power supply is turned on, Since all contents of ROM 63 are checked, there is no risk of malfunction or runaway.

In the above embodiment, the output of the power supply voltage monitoring circuit 41 is input to the multiplexer 42 and then to the CPU 44 via the A/D converter 43. It may also be configured to input the information to the CPU 44 via the CPU 44 .

As described in detail, the present invention detects fluctuations in power supply voltage with a time delay, detects whether the detected voltage is equal to or higher than a predetermined value, and detects whether the detected voltage is less than the predetermined value. The contents of the read-only memory are checked in advance, and if the detected voltage is above a predetermined value, the contents of the read-only memory are checked separately and the fuel injection is controlled, so the car's ignition key is turned on. If this happens and the central processing unit starts, the detected voltage of the power supply voltage is less than a predetermined value, and in this case, all contents of the F-only memory are checked to prevent the central processing unit from malfunctioning or running out of control. I can do it.

On the other hand, if the central processing unit is reset and restarted due to cranking while driving, etc., the detected voltage of the power supply voltage is higher than a predetermined value, and in this case, the contents of the read-only memory are divided and checked. Therefore, starting performance can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing one embodiment of an electronic fuel injection device according to the present invention, and FIG. 2 is an engine control unit (EC) equipped with an electronic fuel injection device according to the present invention.
FIG. 3 (A) is a block diagram showing one embodiment of U), and FIG. 3 (B) is a detailed circuit diagram of the power supply voltage monitoring circuit in FIG. 2.
(C) is an explanatory diagram of the operation of the power supply voltage monitoring circuit of Fig. 3 (A,), Fig. 4 is a flowchart for explaining the operation of the ECU of Fig. 2, especially the CPLI, and Fig. 5 (A) (
B) and (C) are flowcharts for explaining the conventional example, and FIG. 6 is a timing chart for explaining the operation of the CPU when the power supply voltage fluctuates. 31.45 ... Read only memory (4 to RO),
32...Power supply voltage monitoring means, 33, 44...Central processing unit (CPU), 41...Power supply voltage monitoring circuit, 50
Solenoid drive circuit, 51 Electromagnetic injection valve (I
NJ). Name of agent: Patent attorney Shigetaka Awano and 1 other person No. 3
Figure 1 (A) (B> υON→OFF Figure 1 (A) (B)

Claims (2)

[Claims] (1) A read-only memory that stores programs, etc. for performing fuel injection control, and a power supply voltage monitoring means that detects the power supply voltage with a time delay and detects whether the detected voltage is equal to or higher than a predetermined value. and checking all the contents of the read-only memory when the voltage detected by the power supply voltage monitoring means is less than a predetermined value, and checking the contents of the read-only memory when the voltage detected by the power supply voltage monitoring means is equal to or higher than a predetermined value. An electronic fuel injection device that has a central processing unit that performs divided checks and controls fuel injection. (2) The central processing unit checks all the contents of the read-only memory when the detected voltage of the power supply voltage monitoring means is less than a predetermined value, or when the previous check was not normal, and The electronic fuel injection device according to claim 1, wherein the electronic fuel injection device divides and checks the contents of the read-only memory and performs fuel injection control when the detected voltage is equal to or higher than a predetermined value or when the previous check was normal. .