JPH0588381B2 - - Google Patents

Description

[Detailed description of the invention]

Object of the Invention [Field of Industrial Application] The present invention relates to an electronic fuel injection control device, and more specifically, an electronic fuel injection control device that realizes suitable fuel injection control even when the power supply voltage drops during starting of an internal combustion engine. Regarding. [Prior Art] In recent years, electronic control of internal combustion engines has progressed, and the amount of fuel supplied to the internal combustion engine is calculated by a microcomputer based on the operating conditions of the internal combustion engine, and the opening time of the fuel injection valve is controlled. Electronic fuel injection controls (EFI) have become widespread. In such an electronic fuel injection control device, the microcomputer that calculates the fuel injection time, etc. must naturally operate normally, but since it is an electronic device, it is inevitably affected by power supply voltage fluctuations. Particularly during startup, the power supply voltage can drop considerably as the starter drives a large load, and it is not possible to guarantee the operation of the microcomputer when the battery, which is the power supply, is weakening or at low temperatures. In some cases, the voltage dropped to levels that could not be used. Therefore, in internal combustion engines equipped with conventional electronic fuel injection control devices, a separate system of fuel injection valves (start injectors, STJs) that operate stably even at low voltage is used separately from this electronic fuel injection control device.
is installed in the intake pipe and combined with a bimetallic time switch (TZS) to ensure that fuel is injected for a certain period of time at startup, as well as backup means that stores the fuel injection time at startup in advance. When the power supply voltage falls below a predetermined voltage, the output of the backup means is used instead of the calculation result of the microprocessor to perform fuel injection (see ``Fuel Injection for Internal Combustion Engines'' in Japanese Unexamined Patent Publication No. 58-217737). A variety of devices have been proposed, including a control device. [Problems to be Solved by the Invention] Against the background of the prior art, the problems to be solved by the present invention are as follows. (1) When a start injector (STJ) is used to control fuel injection during startup, electrical and fuel systems must be prepared that are separate from the system that performs normal fuel injection, resulting in a complicated device configuration. This resulted in problems such as a decrease in reliability as a whole, an increase in the number of manufacturing steps, and a rise in costs. This problem can be solved by providing a backup method.
If the correctness of the calculation output of the microprocessor is not guaranteed, the same applies to the case where the fuel injection is performed using the output of the backup means. (2) Devices equipped with a device other than a microprocessor for fuel injection when the power supply voltage drops such as during startup are as described above, and below we will consider a device equipped with a microprocessor. Since the maximum load on the starter occurs when any one cylinder of the internal combustion engine is in the latter half of the compression stroke, the battery voltage pulsates accordingly when the internal combustion engine is started. Therefore, for a microprocessor, instead of always being in a state where the voltage can operate normally or not, the voltage range that can operate normally and the voltage that cannot operate normally depends on the pulsation. The range may be repeated. As a result, once the entire microcomputer is reset due to a voltage that does not guarantee normal operation, the microcomputer will start programming from initial processing every time the power supply voltage returns to normal. In the initial processing, various operating conditions such as the rotation speed of the internal combustion engine and the temperature of the cooling water are read, the fuel injection amount is calculated, and after the initial processing,
Fuel injection is finally performed, but the power supply voltage drops again and before fuel injection can be performed,
Alternatively, the reset may occur again during fuel injection, resulting in the problem that the necessary amount of fuel injection at the time of starting cannot be secured. In addition, as a result of spike-like fluctuations in the power supply voltage and wild fluctuations, fuel injection may be interrupted during injection, but after the interruption, fuel injection is restarted from the beginning, resulting in a reduction in the amount of fuel injected. It was also thought that the problem of excess would arise. SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide an electronic fuel injection control device that solves the problems (1) and (2) above and can perform suitable fuel injection control at startup with a simple configuration. Structure of the Invention [Means for Solving the Problems] The means taken to solve the above problems in order to achieve the above object are summarized as follows, as shown in Figure 1. . an operating condition detection means for detecting an operating condition of the internal combustion engine; a fuel injection means for injecting fuel into the internal combustion engine; a fuel injection amount calculated based on the detected operating condition of the internal combustion engine; a fuel injection control means that performs main fuel injection in synchronization with the rotation of the internal combustion engine; a power supply voltage monitoring means that monitors a state of a power supply voltage; determining means for determining whether the power supply voltage has returned from below the predetermined voltage to above the predetermined voltage; an asynchronous injection means for performing fixed-quantity asynchronous injection; and when the power source voltage becomes equal to or less than the predetermined voltage while the asynchronous injection is being performed by the asynchronous injection means;
A stop means for stopping the asynchronous injection; and a stop means for storing the amount of fuel injected up to the time when the stop means stops the asynchronous injection, and storing the stored contents even when the power supply voltage falls below the predetermined voltage. and a storage means for storing information from the predetermined amount in the asynchronous injection which is stopped by the stopping means and then is re-executed by the asynchronous injection means when the power supply voltage returns from below the predetermined value to above the predetermined value again. a correction means for correcting the asynchronous injection amount so that the amount of fuel is injected by subtracting the amount of fuel stored in;
The gist of the present invention is an electronic fuel injection control device characterized by comprising: [Operation] According to this, when it is determined that the power supply voltage has returned from below a predetermined voltage that guarantees the operation of the fuel injection control means to above the predetermined voltage, a predetermined amount of asynchronous injection is performed by the asynchronous injection means. When the power supply voltage becomes equal to or lower than the predetermined voltage while the asynchronous injection is being performed by the asynchronous injection means, the asynchronous injection is stopped by the stop means. Then, in the asynchronous injection executed after the fuel stops, the correcting means corrects the fuel to be injected by the predetermined amount minus the amount of fuel injected up to the time of stopping stored in the storage means. [Example] Hereinafter, an example of the present invention will be described in detail based on the drawings. FIG. 2 is a schematic configuration diagram showing a schematic configuration of an internal combustion engine and its peripheral devices as an embodiment of the present invention;
The figure is a block diagram showing the configuration of an electronic control circuit as fuel injection control means. In the figure, 1 is a 4-stroke, 4-cylinder internal combustion engine, 2 is an electronic control circuit as fuel injection control means, and 3 is a battery as a power source. An air cleaner 5 is connected to the intake pipe 4 of the internal combustion engine 1 from upstream.
An air flow meter 7, an intake temperature sensor 9, a throttle valve 11, an idle switch 12, etc. are provided, and the intake air is injected together with fuel injected from an electromagnetic fuel injection valve 17 as a fuel injection means provided in a branch pipe 15. The mixture becomes a mixture and is sucked into a cylinder (not shown). On the other hand, an O2 sensor 2 is installed in the exhaust pipe 19 of the internal combustion engine 1 to detect the oxygen concentration in the exhaust gas composition.
1 is provided. Furthermore, 23 is an igniter, 25 is an igniter 2
The distributor 25 distributes the high voltage generated in the internal combustion engine 1 to the spark plugs (not shown) of each cylinder in synchronization with the rotation of the crankshaft 27 of the internal combustion engine 1. The distributor 25 receives the cylinder discrimination signal Gl of the internal combustion engine 1. and a rotational speed signal Ne. Further, 29 is an ignition switch that connects the battery 3 to the electronic control circuit 2, and 31 is a starter motor 32 that partially operates in conjunction with the ignition switch 29.
33 is a water temperature sensor that detects the temperature Thw of the cooling water of the internal combustion engine 1. The electronic control circuit 2 includes a microcomputer 50
The core includes an analog input circuit 52, an A/D conversion circuit 53, a digital input circuit 54, a backup circuit 56, a signal switching circuit 58, a power supply circuit 60,
It is composed of output signal buffers 62 and 63. The analog input circuit 52 of the electronic control circuit 2 is
Intake air amount as signal from air flow meter 7
Us, cooling water temperature Thw of the internal combustion engine 1 as a signal from the water temperature sensor 33, intake temperature Tha as a signal from the intake temperature sensor 9, voltage +B of the battery 3,
These signals are sequentially A/D converted by the A/D conversion circuit 53 at the next stage and taken into the microcomputer 50. On the other hand, the digital input circuit 54 receives the cylinder discrimination signal Gl and rotational speed signal Ne generated by the distributor 25, the lean/rich signal Ox as a signal from the O2 sensor 21, and the information that the throttle valve 11 is fully closed. The signal Idle from the idle switch 12 indicating the state and the signal STA indicating the state of the starter switch 31 are input to the microcomputer 5.
0 to the backup circuit 56. The power supply circuit 60 inputs the battery voltage +B through the ignition switch 29 and the backup voltage Batt without going through the ignition switch 29, and outputs the voltage to the microcomputer 5.
0 and another constant voltage Vc to be supplied to other circuits.
In addition, the power supply circuit 60 monitors the voltage of the constant voltage Vsub and generates a signal, and sends a watchdog clear signal from the microcomputer 50 to notify by software that the microcomputer 50 is operating normally. Initial signal of microcomputer 50 based on wdc etc.
It also operates as a power sequence to generate init, but this will be explained later. As shown in FIG. 4, the microcomputer 50 has a well-known microprocessor (MPU) 70, ROM 71, RAM 73, input port 74, output port 76, clock generation circuit 78, common bus 79, etc. integrated into one chip. It is a one-chip microcomputer, and in particular, in this embodiment, it has an address decoder 81 and an R-S flip-flop 8.
2. Inverter 83, gated bus driver 84
It also has a built-in wi signal detection circuit 86 consisting of the following.
Note that the clock generation circuit 78 is an external crystal oscillator 8.
8 and generates the basic operating clock for the MPU 70, as well as a signal for starting an interrupt every 4 msec, which will be described later. The microprocessor 70 reads the operating conditions of the internal combustion engine 1 through the input port 74, and
The ignition timing, fuel injection amount, and injection timing are calculated. Then, through the output port 76, the A/D
In addition to the control signal of the conversion circuit 53, the ignition timing control signal ig is sent to the backup circuit 56, and the signal switching circuit 5
Fuel injection control signals τ1, τ2 are supplied to power supply circuit 6.
A watchdog clear signal wdc is output at 0, respectively. Here, the fuel injection control signal τ1 is the internal combustion engine 1.
The fuel injection control signal τ2 is a signal that controls the normal main fuel injection that is output in synchronization with the rotation of the engine, and the fuel injection control signal τ2 is a signal that controls the starting fuel injection performed in the present invention. The handling of the fuel injection control signal τ2 will be explained in detail later based on a flowchart. The backup circuit 56 is a circuit for supplementing control when the microcomputer 50 stops operating normally, and operates as follows. The microcomputer 50 is controlled by the microprocessor 70, and when the internal combustion engine 1 is in operation, the ignition timing control signal ig is determined based on the rotational speed Ne of the internal combustion engine 1, regardless of whether it is starting or not. It is output at predetermined intervals. Therefore, when the ignition timing control signal ig is no longer output for a predetermined period of time, the microcomputer 50 determines that there is an abnormality, and outputs the ignition signal at a predetermined timing based on the cylinder discrimination signal Gl and the rotational speed signal Ne. IGt is output to the igniter 23 via the buffer 62. At the same time, the microcomputer 50 outputs a predetermined fuel injection amount control signal τ3 as a signal indicating that there is an abnormality.
It is output to the signal switching circuit 58 along with fail. The signal switching circuit 58 normally receives the fuel injection control signals τ1 and τ2 output from the microcomputer 50 and outputs the fuel injection signal τp for opening and closing the electromagnetic fuel injection valve 17 via the buffer 63. When the backup circuit 56 detects an abnormality in the microcomputer 50 and outputs a signal, the electromagnetic fuel injection valve is 17. FIG. 5 shows an example in which the signal switching circuit 58 is constructed of known logic gates. An example of the control of the internal combustion engine 1 performed in the above configuration is shown in the time chart of FIG. Next, the configuration and function of the power supply circuit 60 will be explained based on the circuit diagram of FIG. 7, and the function of the wi signal detection circuit 86 in the microcomputer 50 will also be described. Mention an example. As shown in FIG. 7, the power supply circuit 60 includes a constant voltage output section 93 that generates a constant voltage Vsub supplied to the microcomputer 50 and a constant voltage Vc supplied to circuits other than the microcomputer 50;
It consists of a wi signal output section 95 that monitors the voltage of Vsub, and an initial signal generation circuit 97 that generates an initial signal in cooperation with the watchdog clear signal wdc of the microcomputer 50. The constant voltage output section 93 includes a regulator 101 that generates a constant voltage Vc using battery voltage +B as a power source.
and a regulator 102 that generates a constant voltage Vsub using the battery voltage Batt as a voltage source that does not go through the ignition switch 29. The wi signal output section 95 is a circuit that monitors the voltage of the constant voltage Vsub using the reference voltage Vdl formed internally by the operational amplifier OP1, and is connected to the resistor R.
Using the hysteresis formed by the voltage division by R11, R12, and R13, when the constant voltage Vsub becomes lower than the judgment voltage V2, the output signal is set to low active, and the judgment voltage V1 is higher than the voltage V2.
It is configured to raise the level to a high level when the level exceeds that level. Here, the judgment voltage V2 is set as a voltage up to which the MPU 70 in the microcomputer 50 can judge that its own operation is normal;
V1 is set as a voltage that allows the MPU 70 to judge on its own that it can normally resume control of fuel injection, etc. if it is higher than this voltage, and by providing a listeresis voltage (ΔV) to both, it is possible to This prevents chattering during operation. Note that the constant voltage Vsub fluctuates when the voltage Batt of the battery 3 decreases beyond the capacity of the regulator 102. As mentioned in the explanation of the input/output signals of the microcomputer 50, the initial signal generation circuit 97 is activated when the MPU 70 goes out of control due to a drop in power supply voltage, noise, etc.
When Vsub drops to a voltage at which the MPU 70 can no longer be expected to operate, an initial signal is output to stop the microcomputer 50, and also serves as an initial signal generation when the electronic control circuit 2 is powered on. The output signal of the above-mentioned wi signal output section 95 is sent to the wi signal detection circuit 86 in the microcomputer 50.
It is connected to the S terminal of the R-S flip-flop 82. Since the output of the inverter 83 is normally at a high level, once the signal becomes low active, the R-S flip-flop 82 is set and its output Q is at a low level (corresponding to signal 0).
is set to . The MPU 70 outputs the address set to the wi signal detection circuit 86, opens the gated bus driver 84 via the address decoder 81, and can read the state of the output Q of the R-S flip-flop 82. Alternatively, data can also be written to the R terminal of the R-S flip-flop 82 via the address decoder 81. The truth table of the R-S flip-flop 82 is as follows.

[Table] Here, Q _o-1 indicates that the output Q maintains the state at the time immediately before the state of the R and S terminals changed. Therefore, once the signal becomes low level, even if the MPU 70 writes level 1 to the wi signal detection circuit 86, the state of the output Q remains low level. However, constant voltage Vsub
When becomes higher than the determination voltage V1 and the signal becomes a high level, the state of the output Q is inverted by the write operation from the MPU 70 and becomes a high level.
In addition, the wi signal detection circuit 8 that the MPU 70 reads and writes
Address No. 6 is hereinafter referred to as WI port. The output Q of the R-S flip-flop 82 is RAM
When this signal Q becomes low level, the write signal line in the RAM 73 is inactivated, and no data can be written to the RAM 73. This is RAM7
Since the data write control signal line in 3 is low active (writing is possible when it is low level), when the signal Q becomes low level, the write terminal R/ of RAM 73 is This can be easily realized by a configuration in which the voltage is set equal to the power supply voltage Vc. Regarding the processing performed by the MPU 70 of the microcomputer 50 in the electronic fuel injection control device 2 of this embodiment having the above hardware configuration,
This will be explained based on the flowchart shown in FIG.
The MPU 70 repeatedly executes an interrupt routine (started every 4 msec) shown in the flowchart of FIG. 9 as control of starting fuel injection. first,
The processing at each step will be explained. Step 200: Determine whether the starter 32 is being driven or not based on the state of the signal STA. Steps 210 and 220: Write a value 1 to the WI port, that is, the wi signal detection circuit 86. Steps 230 and 240: Determine whether the value of the WI port is 1 or not. Step 250: Determine whether the value of the variable CTIME is greater than or equal to t2. Step 260: Determine whether the value of the variable CTIME is less than t2. Step 270: Processing is performed to set the variable CTIME to the value t1. Note that here, the value t1 is set as a value that is two or more larger than the value t2. Step 280: Variable used as counter
Performs processing to set CIIME to 0. Step 290: Increment the variable CTIME by 1, that is, CTIME←CTIME+1.
At this time, the value of the variable CTIME is also stored in a predetermined area in the RAM 73. Step 300: Output fuel injection control signal τ2
Performs processing to change or maintain the on state. Step 310: Output fuel injection control signal τ2
Performs processing to change or maintain the off state. The control by this interrupt routine that performs the above processing and judgment is executed in the following order. (1) First, it starts from step 200, but the ignition switch 29 is turned on and the battery is drained.
Immediately after supplying the voltage +B to the electronic control circuit 2, the starter switch 31 has not yet been closed, so the starter 32 has not been turned on, and the determination at step 200 is "NO". Then, the process proceeds to step 210.
After writing 1 to the WI port in step 210, the value t1 is written to the variable CTIME in step 270, and in step 310, the fuel injection control signal τ2 is turned off, and the process exits to RTN and starts the first execution of this interrupt routine. finish. (2) Eventually, when the starter switch 31 is closed, the starter 32 receives power from the battery 3 and begins to rotate, driving the internal combustion engine. When this interrupt routine is started, step 200 is executed.
The judgment is “YES” and the process goes to step
Proceed to 230, WI port = 1? A judgment will be made. Since the value 1 was written to the WI port in the previous processing prior to starting the current interrupt routine, the constant voltage Vsub, which is the power source for the microcomputer 50, decreases due to the addition of the load of the starter 32. If not, the value of the WI port remains 1, and if the constant voltage Vsub is below the judgment voltage V2, the value of the WI port is 0.
It is becoming. If the capacity of the battery 3 has sufficient margin and the constant voltage Vsub will not drop, the determination at step 230 is ``YES'' and the process proceeds to step 260, where it is determined that CTIME<t2. The value of the variable CTIME is set at step 270 in the first interrupt routine processing.
Since it is set to t1, the judgment at step 260 is "NO", and the process moves to step 310, where the fuel injection control signal τ2 is kept in the OFF state and exits to RTN, ending this interrupt routine. do. (3) On the other hand, when the load of the starter 32 is applied due to the battery 29 being weak, etc., the voltage +B of the battery 29 decreases significantly, and the constant voltage Vsub to the microcomputer 50 also falls below the judgment voltage V2. If , step 230
Judgment is "NO" (WI port = 1 does not hold)
The process then proceeds to step 220. step
At 220, the value 1 is written to the WI port, and at the following step 240, it is again determined whether the WI port is 1 or not. If the signal is at a low level, the value of the WI port will not be updated to 1 even if the MPU 70 writes the value 1. Therefore, the value of the WI port will not be updated to 1 even if the MPU 70 writes the value 1. Therefore, the value of the WI port is not updated in step 240 until the constant voltage Vsub falls below the judgment voltage V2 and then becomes equal to or higher than the judgment voltage V1. The determination is "NO" and the process proceeds to step 310-RTN as described above.
After the load of the starter 32 pulsates and the constant voltage Vsub exceeds the judgment voltage V1, step 230 is performed.
- In the judgment/processing at step 220, the value of the WI port is 1, and the judgment at step 240 is "YES". This situation is shown in FIG. In other words, when the signal becomes low active, the state of the WI port becomes low level, and the signal
First MPU70 after wi becomes high level
It returns to high level by writing data 1. (4) If the judgment in step 240 is “YES”, that is, WI
When port=1, the process proceeds to step 250,
It is determined whether the value of the variable CTIME is greater than or equal to t2. The value of the variable CTIME is initially
Since the value set as the value t1 remains unchanged at step 270, the determination at step 250 is "YES" and the process proceeds to step 280. In step 280, we assume that asynchronous starting fuel injection will now begin.
Set the value of variable CTIME to 0. In the following step 300, the fuel injection control signal τ2 is turned on, and the flow exits to RTN to end this interrupt routine.
When the output of the fuel injection control signal τ2 is turned on, the output signal τp of the electronic control circuit 2 becomes active, and the electromagnetic fuel injection valve 17 is opened. (5) Under the above conditions, when this interrupt routine is started next time, the value of the WI port will be 1 until the constant voltage Vsub decreases again and falls below the judgment voltage V2, so the step 230 will be executed. The determination is ``YES'', and in step 260 it is determined whether the variable CTIME is less than the value t2. The value of the variable CTIME is set to 0 in step 280 and is incremented by 1 each time step 290 is executed, so this value is set to 0 at t2.
Until this point is reached (in this case, within 50 msec), the determination at step 260 is "YES", and the processing at steps 290 and 300 is continued to execute asynchronous fuel injection using the fuel injection control signal τ2. (6) While the constant voltage Vsub is greater than or equal to the judgment voltage V1,
The above-mentioned asynchronous starting fuel injection (50 msec) by the MPU 70 ends, and the constant voltage Vsub eventually decreases, and again from the judgment voltage V2 or lower to the judgment voltage V1
Returning to the above, the same control as in (5) above is performed. (7) However, during the execution of the asynchronous starting fuel injection described in (5) above, a spike-like fluctuation occurs in the power supply voltage, and the constant voltage Vsub also changes to the judgment voltages V1 and V2.
This may cause asynchronous starting fuel injection to be interrupted. At this time, the value of the WI port becomes zero, and even though the asynchronous starting fuel injection is in progress, the judgment at step 230 becomes "NO", and the process moves to step 220, and repeats steps 220 - 240 - 310. -The flow will be similar to RTN. However, when the constant voltage Vsub recovers immediately after this and becomes equal to or higher than the judgment voltage V1, WI
As a result of the port being written once by the MPU 70 (step 220), the value becomes 1, and the judgment becomes ``YES'' in step 240, and the step continues.
Proceed to 250. At this time, the value of the variable CTIME is changed to the RAM 73 due to the previous successful execution of step 290.
Since the value stored in the predetermined area of ``CTIME'' is saved as it is, the judgment at step 250 is "NO", that is, the value of the variable CTIME is not counted up and the asynchronous starting fuel injection is interrupted midway. Step 290
, and thereafter continues the previously interrupted control in (5) above. Therefore, the amount of fuel injected by asynchronous starting fuel injection always depends on the fuel injection time.
The amount of fuel is controlled to be equivalent to 50 msec, and even spike-like voltage fluctuations will not cause an excessive amount of fuel. Throughout the above control, the RAM 73 in the microcomputer 50, as described above,
When the constant voltage Vsub becomes lower than the judgment voltage V2, it is configured to prohibit writing and protect the contents, and even if the battery voltage +B pulsates due to fluctuations in the load of the starter 32, the value of the variable CTIME is saved. ing. An example of asynchronous startup fuel injection control performed by repeatedly executing this interrupt routine at startup of the internal combustion engine 1 is shown in the timing chart of FIG. 11. In other words, in fuel injection at the time of starting, the variable is changed every time the constant voltage Vsub goes below the judgment voltage V2 and returns to above the judgment voltage V1.
It starts using the value of CTIME as a counter (section in Figure 11), and the value of variable CTIME is t2.
If so, it will be stopped from then on (section). A constant voltage is generated during this asynchronous starting fuel injection.
When Vsub decreases and fuel injection is interrupted, when the constant voltage Vsub recovers, fuel injection of the remaining amount of one asynchronous fuel injection amount is performed (section). Normal main fuel injection is performed separately from this, and once the constant voltage Vsub is established, it is performed by normal fuel injection control (section). In this embodiment configured as above,
Constant voltage that is the power supply voltage of the microprocessor 70
The state of Vsub is monitored by the wi signal output unit 95, and when the voltage falls below the voltage that can guarantee the operation of the microprocessor 70 (here, the judgment voltage V2), the contents of the RAM 73 are saved and the operation of the microprocessor 70 is resumed. When the voltage exceeds the voltage at which there is no problem in restarting (here, the judgment voltage V1), the pulse width
Asynchronous fuel injection unique to 50msec startup is executed. Therefore, even if the constant voltage Vsub fluctuates, including a voltage range where the operation of the microprocessor 70 cannot be guaranteed at startup,
When the determination voltage is equal to or higher than V1, asynchronous starting fuel injection is immediately started, and reliable fuel injection at starting can be expected, and the intake of combustible mixture into the cylinder is ensured. Furthermore, the value of the variable CTIME in RAM73 is saved, so if fuel injection is interrupted due to fluctuations in the constant voltage Vsub during asynchronous starting fuel injection, the constant voltage
Since the remaining amount of fuel is injected in the asynchronous starting fuel injection that is executed when Vsub has recovered, the starting fuel injection amount supplied to the internal combustion engine 1 may be excessive due to spike-like power supply voltage fluctuations. It will never happen. Furthermore, even if the constant voltage Vsub falls further below the judgment voltage V2, causing the signal in the power supply circuit 60 to be output and the microcomputer 50 is reset, the constant voltage Vsub will recover and the judgment voltage will be reduced.
If it is equal to or higher than V1, asynchronous starting fuel injection is performed using the fuel injection control signal τ2 without waiting for the main fuel injection, which is performed by calculating the fuel injection time from the rotational speed Ne of the internal combustion engine 1 and other parameters. Therefore, when the starter 32 can rotate, fuel can be reliably sucked into each cylinder of the internal combustion engine 1. Furthermore, in this embodiment, only a few electrical circuits are added, and fuel injection is always controlled under a single microprocessor 70, and the start injector, its fuel system, etc. It is possible to perform reliable fuel injection at startup with a simple configuration. In this example, the constant voltage Vsub is the constant judgment voltage.
When the microprocessor 70 becomes unable to output the ignition timing control signal ig due to V2 or lower,
The backup circuit 56 controls the ignition timing and fuel injection of the internal combustion engine 1, and it can be said that the startability of the internal combustion engine 1 is almost perfect in the voltage range in which the starter 32 is driven. . Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments in any way.
For example, instead of the configuration shown in FIG. It goes without saying that the invention can be implemented in various ways without departing from the spirit of the invention, such as a configuration in which it is input as a signal. Effects of the Invention As detailed above, according to the electronic fuel injection control device of the present invention, proper fuel injection can be reliably achieved at the time of starting without requiring a start injector or its fuel system. This provides an excellent effect of ensuring sufficient startability of the internal combustion engine 1. In addition, since the configuration can be simplified, problems such as reliability of the device and trouble and cost of the manufacturing process are improved. Furthermore, according to the present invention, when asynchronous injection is stopped midway, the injection amount injected before it is stopped is stored, and the next asynchronous injection is injected by subtracting this memorized injection amount. Therefore, as a result of spike-like fluctuations in the power supply voltage and wild fluctuations, even if fuel injection is interrupted, the next injection will be subtracted by the injection amount that was injected until the previous interruption, resulting in an excessive fuel injection amount. This has the excellent effect of improving drivability.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is a schematic configuration diagram showing the configuration of an internal combustion engine and its peripheral devices as an embodiment of the present invention, and FIG. 3 is a configuration diagram of the electronic control circuit 2. 4 is a block diagram showing the configuration of the microcomputer 50, FIG. 5 is a logic circuit diagram showing an example of the configuration of the signal switching circuit 58,
FIG. 6 is a timing chart showing an example of control of ignition timing and fuel injection by the backup circuit 56, FIG. 7 is a circuit diagram showing the configuration of the power supply circuit 60, and FIG. 8 is an example of a configuration for inhibiting writing to the RAM 73. Circuit diagram, FIG. 9 is a flowchart of a 4 msec interrupt routine showing a control example in the embodiment, the first
FIG. 0 is a timing chart explaining the state of the WI port, and FIG. 11 is a timing chart showing an example of fuel injection control in the embodiment. 1... Internal combustion engine, 2... Electronic control circuit, 3...
Battery, 17... Solenoid fuel injection valve, 29...
Ignition switch, 31... Starter switch, 32... Starter, 50... Microcomputer, 60... Power supply circuit, 70... Microprocessor (MPU), 73... RAM, 82...
R-S flip-flop, 86...wi signal detection circuit, 95...wi signal output section.

Claims (1)

[Scope of Claims] 1. Operating condition detection means for detecting operating conditions of an internal combustion engine; fuel injection means for injecting fuel into the internal combustion engine; and calculating a fuel injection amount based on the detected operating conditions of the internal combustion engine. a fuel injection control means for controlling the fuel injection means to perform main fuel injection in synchronization with the rotation of the internal combustion engine; a power supply voltage monitoring means for monitoring a state of a power supply voltage; a determining means for determining whether the voltage has returned from below a predetermined voltage that guarantees operation of the means to above the predetermined voltage; and whenever it is determined that the power supply voltage has returned from below the predetermined voltage to above the predetermined voltage. an asynchronous injection means for performing asynchronous injection of a predetermined amount, and when the power supply voltage falls below the predetermined voltage while the asynchronous injection is being performed by the asynchronous injection means;
A stop means for stopping the asynchronous injection; and a stop means for storing the amount of fuel injected up to the time when the stop means stops the asynchronous injection, and storing the stored contents even when the power supply voltage falls below the predetermined voltage. and a storage means for storing information from the predetermined amount in the asynchronous injection which is stopped by the stopping means and then is re-executed by the asynchronous injection means when the power supply voltage returns from below the predetermined value to above the predetermined value again. a correction means for correcting the asynchronous injection amount so that the amount of fuel is injected by subtracting the amount of fuel stored in;
An electronic fuel injection control device comprising: