JPH068618B2 - Electronic fuel injection control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic fuel injection control device, and more particularly to an electronic fuel injection control device that realizes suitable fuel injection control even when the power supply voltage drops at the start of an internal combustion engine. The present invention relates to a fuel injection control device.

[Prior Art] In recent years, electronic control of the internal combustion engine has been advanced, 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 to control the opening time of the fuel injection valve. Electronic fuel injection control devices (EFIs) that are controlled by such a method are widely used. In such an electronic fuel injection control device, the operation of the microcomputer for calculating the fuel injection time and the like must be normal, but since it is an electronic device, it is unavoidable that it is affected by power supply voltage fluctuations. In particular, when starting, a large load such as a starter is driven, so the power supply voltage may drop considerably, and it is not possible to guarantee the operation of the microcomputer when the battery that is the power supply is weak or when the temperature is low. In some cases, the voltage dropped.

Therefore, in an internal combustion engine equipped with a conventional electronic fuel injection control device, apart from this electronic fuel injection control device,
A separate fuel injection valve (start injector, STJ) that operates stably even at low voltage is installed in the intake pipe and combined with a time switch (TZS) that uses bimetal to ensure that fuel is injected for a fixed time during startup. And a backup means for storing the starting fuel injection time in advance, and when the power supply voltage becomes equal to or lower than a predetermined voltage, the fuel injection is performed using the output of the backup means instead of the calculation result of the microprocessor. What can be performed (Japanese Patent Laid-Open No. Sho 58)
Various proposals have been proposed, such as "Fuel injection control device for internal combustion engine" in Japanese Patent Application Laid-Open No. 217737).

[Problems to be Solved by the Invention] Against the background of such conventional technology, the problems to be solved by the present invention are as follows.

(1) If a start injector (STJ) is used for fuel injection control at the time of starting, it is necessary to prepare an electrical and fuel system that is different from the system that performs normal fuel injection, which complicates the device configuration. Therefore, there is a problem that the reliability is lowered as a whole, the number of manufacturing processes is increased, and the cost is increased. Further, the fuel injection amount is uniquely determined by the start timer, and it is also difficult to perform precise control by the starting conditions of the internal combustion engine, such as the cooling water temperature and the number of fuel injections. This also applies to the case where the backup means is provided and fuel injection is performed by the output of the backup means when the correctness of the arithmetic output of the microprocessor is not guaranteed.

(2) Since the maximum load is applied to the starter when any one of the cylinders of the internal combustion engine is in the latter stage of the compression stroke, the battery voltage pulsates accordingly when the internal combustion engine is started. Therefore, in the case where the microprocessor does not always enter a state in which it can operate normally or a voltage in which it cannot operate normally, when the voltage range that can operate normally and the voltage range that does not operate normally are repeated according to the pulsation. There is. As a result, once a voltage that does not guarantee normal operation is reset and the entire microcomputer is reset, even if the power supply voltage is restored to normal, the microcomputer is to start from its initial state. Therefore, after the initial processing, various operating conditions such as the rotation speed of the internal combustion engine and the water temperature of the cooling water are read, the fuel injection amount is calculated, and fuel injection is finally performed, but the power supply voltage drops again, The reset may be applied again before the fuel injection or during the fuel injection, which may eventually lead to a problem that the fuel injection amount required at the time of starting cannot be secured.

It is therefore an object of the present invention to solve the problems (1) and (2) described above and to provide an electronic fuel injection control device capable of performing suitable fuel injection control at the time of starting with a simple configuration.

A further object of the present invention is to prevent the vicinity of the engine intake port from being in a so-called fuel fog state due to fuel injection at the time of starting.

Structure of the Invention [Means for Solving Problems] Means for solving the above problems in order to achieve the above object have the following structure as shown in FIG. .

An operating condition detecting means for detecting an operating condition of the internal combustion engine, a fuel injecting means for injecting fuel into the internal combustion engine, a fuel injection amount based on the detected operating condition of the internal combustion engine, and the fuel injection And a fuel injection control means for controlling the fuel injection control means for injecting main fuel in synchronism with the rotation of the internal combustion engine, and a predetermined power supply voltage for ensuring the operation of the fuel injection control means. Power supply voltage monitoring means for detecting that the power supply voltage is equal to or higher than the voltage, and based on the detection signal from the power supply voltage monitoring means, the asynchronous injection by the fuel injection means during the starter operation period when the power supply voltage is equal to or higher than the predetermined voltage. Asynchronous injection means for performing and the asynchronous injection time by this asynchronous injection means are accumulated, and also when the power supply voltage is lower than the predetermined voltage,
Timer means for storing the accumulated time, asynchronous injection stop means for stopping the asynchronous injection when the accumulated time of the timer means exceeds a predetermined time determined according to the detected operating condition, the starter Stop detecting means for detecting an operation stop of the starter, a measuring means for measuring an elapsed time from the stop of the starter operation, and an initializing means for initializing the accumulated time when the elapsed time reaches a predetermined time. An electronic fuel injection device characterized by the above.

[Operation] According to this, the asynchronous injection is executed by the asynchronous injection means during the starter operation period at which the operation of the fuel injection means is guaranteed to be equal to or higher than the predetermined voltage. Then, the asynchronous injection time is accumulated by the timer means, and when the accumulation becomes equal to or more than the predetermined value, the asynchronous injection stop means stops the asynchronous injection.

Further, the elapsed time after the starter has been stopped is measured by the measuring means, and when the elapsed time exceeds the predetermined time, that is, when the engine is started and the engine rotates for the predetermined time, or the predetermined time elapses. At the time of restarting after the lapse of time, the accumulated time is initialized.

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

FIG. 2 is a schematic configuration diagram showing a schematic configuration of an internal combustion engine and its peripheral devices as one embodiment of the present invention, and FIG. 3 is a block diagram showing a configuration of an electronic control circuit as fuel injection control means. is there.

In the figure, 1 is a 4-cycle 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. The intake pipe 4 of the internal combustion engine 1 is provided with an air cleaner 5, an air flow meter 7, an intake temperature sensor 9, a throttle valve 11, an idle switch 12 and the like from the upstream side, and intake air is provided in a branch pipe 15 as fuel injection means. As a mixture with the fuel injected from the electromagnetic fuel injection valve 17, the mixture is drawn into a cylinder (not shown). On the other hand, the exhaust pipe 19 of the internal combustion engine 1 is provided with an O ₂ sensor 21 for detecting the oxygen concentration in the exhaust gas composition.

Further, 23 is an igniter, 25 is a distributor that distributes the high voltage generated in the igniter 23 to an ignition plug (not shown) of each cylinder in synchronization with the rotation of the crankshaft 27 of the internal combustion engine 1, and the distributor 25 is the internal combustion engine 1 Of the cylinder discrimination signal G ₁ and the rotation speed signal Ne. Further, 29 is an ignition switch that connects the battery 3 to the electronic control circuit 2, 31 is a starter switch that turns on / off the starter motor 32 in conjunction with the ignition switch 29, and 33 is the temperature of the cooling water of the internal combustion engine 1. It is a water temperature sensor.

The electronic control circuit 2 uses the microcomputer 50 as a core, and has 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, output signal buffers 62 and 63.
It consists of The analog input circuit 52 of the electronic control circuit 2 uses the intake air amount Us as a signal from the air flow meter 7, the cooling water temperature Thw of the internal combustion engine 1 as a signal from the water temperature sensor 33, and the intake air as a signal from the intake temperature sensor 9. The temperature Ta is input, and these signals are sequentially output by the A / D conversion circuit 53 in the next stage together with the voltage + B of the battery 3
/ D converted and taken into the microcomputer 50.

On the other hand, the digital input circuit 54 includes a cylinder discrimination signal G ₁ and a rotation speed signal Ne, O generated by the distributor 25.
₂ lean / rich signal O as a signal from the sensor 21
x, a signal Idle from the idle switch 12 indicating that the throttle valve 11 is fully closed, and a signal STA indicating the state of the starter switch 31 are input and output to the microcomputer 50 and the backup circuit 56.

The power supply circuit 60 inputs the battery voltage + B via the ignition switch 29 and the backup voltage Batt without passing through the ignition switch 29, and supplies the constant voltage Vsu to the microcomputer 50.
Another constant voltage Vc supplied to b and other circuits
Produces and. In addition, the power supply circuit 60 has a constant voltage Vsu.
The initial signal of the microcomputer 50 is generated based on the watchdog clear signal wdc that monitors the voltage of b to generate the signal wi, and notifies the microcomputer 50 that the microcomputer 50 is operating normally by software. It also operates as a power supply sequence for generating init, which will be described later.

As shown in FIG. 4, the microcomputer 50 includes a well-known microprocessor (MPU) 7 in one chip.
0, ROM 71, RAM 73, input port 74, output port 76, clock generation circuit 78, common bus 79, etc. are integrated into one chip microcomputer. In this embodiment, an address decoder 81, an RS flip-flop 82, Inverter 83, bus driver with gate 84
It also has a built-in wi signal detection circuit 86. The clock generation circuit 78 receives a signal from the external crystal oscillator 88 and generates an operation basic clock for the MPU 70.

The microprocessor 70 reads the operating conditions of the internal combustion engine 1 via the input port 74 and calculates the ignition timing, the fuel injection amount and the injection timing of the internal combustion engine 1. In addition to the control signal of the A / D conversion circuit 53 via the output port 76, the ignition timing control signal ig is supplied to the backup circuit 56, the fuel injection control signals τ ₁ and τ ₂ are supplied to the signal switching circuit 58, and the power supply circuit is supplied. The watchdog clear signal wdc is output to 60. Here, the fuel injection control signal τ ₁ is a signal for controlling the normal main fuel injection that is output in synchronization with the rotation of the internal combustion engine 1, and the fuel injection control signal τ ₂ is the fuel injection at the time of start performed in the present invention. This is a control signal. The handling of the fuel injection control signal τ ₂ will be described in detail with reference to the flowchart below.

The backup circuit 56 is a circuit for supplementing control of the microcomputer 50 when it does not operate normally, and operates as follows. The microcomputer 50 is controlled by the microprocessor 70, and if the internal combustion engine 1 is operating, the ignition timing control signal ig is set at a predetermined interval determined by the rotational speed Ne of the internal combustion engine 1, regardless of whether the internal combustion engine 1 is being started. It outputs after putting. Therefore, when the ignition timing control signal ig is no longer output for a predetermined period of time, the microcomputer 50 determines that it is abnormal, and the ignition signal IGt is determined at a predetermined timing from the cylinder determination signal G ₁ and the rotation speed signal Ne. Is output to the igniter 23 via the buffer 62. At the same time, the predetermined fuel injection amount control signal τ ₃ is output to the signal switching circuit 58 together with the signal fail indicating that the microcomputer 50 is abnormal.

The signal switching circuit 58 receives the fuel injection control signals τ ₁ and τ ₂ that are normally output from the microcomputer 50, and outputs the fuel injection signal τp that opens and closes the electromagnetic fuel injection valve 17 via the buffer 63. But the backup circuit 56
Detects an abnormality in the microcomputer 50 and fails the signal
Is output, the electromagnetic fuel injection valve 17 is controlled by the fuel injection control signal τ ₃ output from the backup circuit 50 instead of the fuel injection control signals τ ₂ and τ ₂ . FIG. 5 shows an example in which the signal switching circuit 58 is configured by a known logic gate.

An example of 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 described with reference to the circuit diagram of FIG.
The operation of the wi signal detection circuit 86 in the above is also described, and an example of the power supply monitoring means of the present invention is referred to.

As shown in FIG. 7, the power supply circuit 60 generates a constant voltage Vsub supplied to the microcomputer 50 and a constant voltage Vc supplied to circuits other than the microcomputer 50, and a voltage of the constant voltage Vsub. And an initial signal generating circuit 97 for generating an initial signal init in cooperation with a watchdog clear signal wde of the microcomputer 50.

The constant voltage output unit 93 includes a regulator 101 that generates a constant voltage Vc by using the battery voltage + B as a power source and a regulator 102 that generates a constant voltage Vsud by using the battery voltage Batt not passing through the ignition switch 29 as a voltage source. .

The wi signal output unit 95 is a circuit that monitors the voltage of the constant voltage Vsub using the reference voltage Vd ₁ formed inside by the operational amplifier OP1, and is formed by voltage division by the resistors R ₁₁ , R ₁₂ , and R _13. When the constant voltage Vsub becomes equal to or lower than the judgment voltage V ₂ by using the generated hysteresis, its output signal w
i is set to low active, and the determination voltage V higher than the voltage V ₂
It is configured to be high level when it becomes ₁ or more. Here, the determination voltage V ₂ is set as a voltage at which the MPU 70 in the microcomputer 50 can determine that its operation is normal up to this voltage, while the determination voltage V ₁ is higher than this voltage. If there is M
The PU 70 itself is set as a voltage at which it can determine that it can normally resume control of fuel injection and the like, and by providing both with a hysteresis voltage (ΔV), the occurrence of operational chattering near the boundary is prevented. ing. The constant voltage Vsub fluctuates when the voltage Batt of the battery 3 exceeds the capability of the regulator 102 and drops. Here, the determination voltages V ₁ and V ₂ are set to be slightly higher than the voltage at which the initial signal init is generated.

The initial signal generation circuit 97 uses the MP as described in the input / output signals of the microcomputer 50.
When the U70 has runaway due to a drop in the power supply voltage or noise, or when the constant voltage Vsub drops to a voltage at which the operation of the MPU 70 can no longer be guaranteed, the initial signal in
It outputs it and stops the microcomputer 50. The initial signal init is the electronic control circuit 2
Also serves as the initial signal when the power is turned on.

The output signal wi of the wi signal output unit 95 described above is connected to the S terminal of the RS flip-flop 82 of the wi signal detection circuit 86 in the microcomputer 50. Inverter 83
Since the output of is normally high level, once the signal wi becomes low active, the RS flip-flop 82 is set and its output Q is low level (corresponding to the signal 0).
Set. The MPU 70 can output the address set to the wi signal detection circuit 86, open the gated bus driver 84 through the address decoder 81, and read the state of the output Q of the RS flip-flop 82.
Alternatively, data can be written to the R terminal of the RS flip-flop 82 via the address decoder 81. The truth table of the RS flip-flop 82 is as follows.

Here, Q _n-1 indicates that the output maintains the state at the time immediately before the state of the R and S terminals changed.
Therefore, once the signal wi becomes low level, the MPU 70
Even if level 1 is written in the wi signal detection circuit 86, the state of the output Q remains low level. However, when the constant voltage Vsub becomes equal to or higher than the determination voltage V ₁ and the signal wi becomes high level, the state of the output Q is inverted and becomes high level by the write operation from the MPU 70. Incidentally, M
The address of the wi signal detection circuit 86 read and written by the PU 70 is hereinafter referred to as a WI port.

A process performed by the MPU 70 of the microcomputer 50 in the electronic fuel injection control device 2 of the present embodiment having the above hardware configuration will be described with reference to the flowchart of FIG. The MPU 70 repeatedly executes the interrupt routine (started every 4 msec) shown in the flowchart of FIG. 8 as the control of the fuel injection at startup. First, the processing in each step will be described.

Step 200: Judge whether the starter 32 is driven or not based on the state of the signal STA.

Steps 210 and 220: The value 1 is written in the WI port, that is, the wi signal detection circuit 86.

Steps 230 and 240: It is judged whether or not the value of the WI port, in other words, the output Q of the flip-flop 82 is 1.

Step 250: The value of the variable CTIME corresponding to the cumulative value of the asynchronous fuel injection amount, in other words, the cumulative value of the asynchronous injection is a predetermined value t ₂ (where t ₂ is 1 of the operating condition of the internal combustion engine).
It is, of course, determined based on the cooling water temperature, which is one of the two).

Step 260: Perform processing for setting the variable CTIME to a predetermined value t ₁ . The value t ₁ is set to be larger than the value t ₂ .

Step 270: Variable CTI used as counter
The process of setting ME to 0 is performed.

Step 275: It is determined whether the value of the variable CTIME is t ₁ or more.

Step 280: The variable CTIME is incremented by 1, that is, CTIME ← CTIME + 1.

Step 290: It is determined whether or not the variable CSTA corresponding to the counter for measuring the elapsed time from the start of turning off the starter 31 is 0.

Step 300: Set variable CSTA to the value t ₃ .

Step 310: Decrement the variable CSTA by one. That is, CSTA ← CSTA-1.

Step 320: Invert or maintain the output fuel injection control signal τ ₂ in the ON state.

Step 330: Invert or maintain the output fuel injection control signal τ ₂ in the off state.

The control by this interrupt routine that performs the above processing and determination is executed in the following order.

(1) First, starting from step 200, immediately after the ignition switch 29 is turned on to supply the voltage + B of the battery 3 to the electronic control circuit 2, the starter switch 31 is not closed yet. , The starter 32 is not turned on, the determination in step 200 is “NO”, and the process proceeds to step 210.
After writing 1 to the WI port in step 210, it is determined in step 290 whether the variable CSTA has the value 0. At this time, CSTA is the initial value 0, so the determination result of step 290 is “YES”, and then CTIME is set to the value t ₁ in step 260, and then the fuel injection control signal τ ₂ is turned off in step 330. The state is entered, and the routine exits to RTN to end the first execution of this interrupt routine.

(2) Eventually, when the starter switch 31 is closed, the starter 32 starts to rotate by receiving the power supply from the battery 3.
Drives an internal combustion engine. Then, when this interrupt routine is activated, the determination in step 200 becomes "YES" and the process proceeds to step 230, where WI port = 1? Is judged. Since the value 1 is written in the WI port in the previous process prior to the activation of the interrupt routine this time, the constant voltage Vsub, which is the power supply of the microcomputer 50, must be lowered by the load of the starter 32. In this case, the value of the WI port remains 1, and if the constant voltage Vsub is equal to or lower than the determination voltage V ₂ , the value of the WI port is 0. When the capacity of the battery 3 has a sufficient margin and the constant voltage Vsub does not decrease, the determination in step 230 becomes "YES" and the process proceeds to step 250 to determine CTIME> t ₂ . Since the value of the variable CTIME is set to the value t ₁ in step 260 in the processing of this interrupt routine for the first time, the determination in step 250 is “YES”, the processing proceeds to step 330, and the fuel injection control signal τ ₂ is maintained in the off state, the routine goes to RTN, and this interrupt routine is ended.

(3) On the other hand, when the load of the starter 32 is applied because the battery 29 is weak, the voltage of the battery 29 +
When B is significantly reduced and the constant voltage Vsub to the microcomputer 50 is also below the determination voltage V ₂ , the determination in step 230 is “NO” (WI port =
1 is not established), and the process proceeds to step 220. In step 220, the value 1 is written in the WI port, and in the subsequent step 240, it is judged again whether or not the WI port is 1. The value of the WI port is not updated to the value 1 even if the MPU 70 writes the value 1 if the signal wi is at the low level, so the constant voltage Vsub is lower than the judgment voltage V ₂ and the step is continued until it becomes the judgment voltage V ₁ or more. The judgment at 240 is "N
"O" and the process proceeds to RTN via step 330 as described above.

(4) After that, after the constant voltage Vsub becomes equal to or higher than the determination voltage V ₁ , the value of the WI port becomes 1 in the determination / processing of Step 230-Step 220, and Step 24
The judgment at 0 is "YES". This situation is shown in FIG. That is, the state of the WI port, that is, the output Q becomes low level when the signal wi becomes low active, and the signal wi
Is returned to the high level by the first writing of the data 1 by the MPU 70 after the signal becomes the high level.

(5) The judgment in step 240 is “YES”, that is, W
When I port = 1, the process proceeds to step 275. At step 275, the variable CTIME ≧ t ₁ ? Is determined and the variable CTIME at this point is t ₁ , so the result of this determination is “YES”, and step 270
Go to. In this step 270, the variable CTIME is set to 0. Next, in step 300, the variable CSTA is set to t ₃
Is set, and then, in step 320, the fuel injection control signal τ ₂ is inverted to the on state, and the routine goes to RTN.

(6) Then, at the next execution of this routine, the output Q
Is "1", the determination result of step 230 is "YES", and step 250 is executed subsequent to this step 230. In this step 250, it is judged whether or not the variable CTIME is larger than t _2. However, since CTIME is 0 at this time, the judgment result of this step 250 is “NO”, and step 2
Proceed to 80. In step 280, a process of incrementing the variable CTIME by "1" is performed. Next, at step 300, the variable CSTA is set to t ₃ ,
At step 320, τ ₂ is maintained in the ON state, and the process goes to RTN.

After the above processing is performed, until the constant voltage Vsub becomes lower than the determination voltage V ₂ again, when this control routine is started, steps 200, 230, 250 and 28 are performed.
The route consisting of 0, 300 and 320 is repeatedly executed.

(7) After that, when the constant voltage Vsub becomes lower than the determination voltage V ₂ , the output Q becomes “0”.
The determination result of 30 is “NO”, and “1” is set in the port at step 220. However, since the output Q is “0”, the determination result of step 240 is “N”.
O ”, and τ ₂ is turned off at step 330.

As described above, from the time when the constant voltage Vsub falls below the judgment voltage V ₂ until it rises above the judgment voltage V ₁ , step 20
The route consisting of 0, 220, 240, 330 is repeatedly executed, and τ ₂ is kept off. Also, the variable C
Since no increment or decrement is performed on TIME and the variable CSTA, the variable C
For TIME, the value immediately before the constant voltage Vsub falls below the determination voltage V ₂ is held, while for the variable CSTA, the value of t ₃ is held.

(8) When the constant voltage Vsub again exceeds the judgment voltage V ₁ , the judgment result of step 240 shows that the output Q is “1”.
Therefore, it is reversed to “YES” and then step 2
At 75, the variable CTIME ≧ t ₁ ? Is determined.
A result of this determination, usually because it is "NO", then step 250 at variable CTIME> t _2? Is determined. Since this determination result is usually "NO", the variable CTIME is then incremented in step 280. Next, at step 300, the variable CSTA is set to t ₃
Is set, and τ ₂ is turned on in step 320, and the process goes to RTN.

As described above, after the constant voltage Vsub exceeds the determination voltage V ₁ , steps 200, 230, 250, 280, 3
The route consisting of 00 and 320 is repeatedly executed, increment processing of the variable CTIME is performed, and τ
₂ is kept on. Also, the variable CSTA is maintained at t ₃ .

(9) If the constant voltage Vsub falls below the judgment voltage V ₂ after the constant voltage Vsub exceeds the judgment voltage V ₁ and before the variable CTIME reaches t ₂ , steps 200, 230, 220, ₂ are performed.
The routine consisting of 40 and 330 is executed and τ ₂ is inverted to the off state.

(10) After that, when the starter switch 31 is turned off,
The determination result of step 200 is inverted to "NO", and after step 210, the variable CSTA = in step 290.
0? Is determined. This determination result is CSTA = t
_Since it is ₃ , it becomes “NO”, and then step 310.
Decrements CSTA.

From the time the starter switch 31 is turned off until it is turned on again, unless the variable CSTA is reduced to 0, the route consisting of steps 200, 210, 290, 310 and 330 is repeatedly executed, and τ ₂ is turned off. While being maintained, the value of the variable CSTA decreases by one.

(11) Then, when the starter switch 31 is turned on again, the same operation as the above (2) and thereafter is performed. Then, when the value of the variable CTIME reaches t ₂ after the constant voltage Vsub exceeds the judgment voltage V ₁ , step 2
The determination result of 50 is inverted to “YES”, and step 330
At, τ ₂ is turned off. After τ _{2 is} turned off, steps 200 and 23 are performed until the constant voltage Vsub falls below the determination voltage V _2.
The route consisting of 0, 250, 330 is executed repeatedly, τ ₂ is kept in the off state and the variable CTIME is maintained.
Is held at t ₂ .

(12) Then, when the constant voltage Vsub is lower than the determination voltage V ₂ , the determination result of step 230 is inverted to “NO”, and the determination result of step 240 after passing through step 220 is also “NO”. Steps 200, 230, 2
The route consisting of ₂₀ , 240, and 330 is repeatedly executed, τ ₂ is in an off state, CTIME is t ₂ , and CSTA is t _3.
Respectively held in. This state is maintained until the constant voltage Vsub exceeds the determination voltage V ₁ .

(13) After that, when the constant voltage Vsub exceeds the determination voltage V ₁ , it is determined in step 240 that the output Q = 1, so the routine proceeds to step 275, and the determination result of this step 275 is “NO. Since the variable CTIME> t ₂ is satisfied, the determination result of the above step 250 is “YES”, and the process goes to the PTN via step 330. Therefore the variable CT
After the IME reaches t ₂ , the constant voltage Vsub changes to the determination voltage V ₁
Above, the τ ₂ does not reverse to the ON state, and therefore asynchronous injection is not performed.

(14) Then, when the starter switch 31 is turned off,
By the execution of step 310, the variable CSTA is decremented by "1". And starter switch 31
If the variable CSTA decreases to 0 before is turned on again, the determination result of step 290 is inverted to “YES”,
In step 260, the variable CTIME is set to t ₁ .

(15) After that, it can be considered that the above-mentioned operations (1) to (14) are normally performed until the engine is started.

As described above, while the asynchronous injection time is integrated at the starter on, it is determined whether the starter off period CSTA is the predetermined value t ₃ or more, and the starter off period CSTA becomes t ₃ or more by the time. When the integrated value CTIME of the asynchronous injection time reaches t ₂ , the subsequent asynchronous injection is stopped. When the starter-off period CSTA becomes t ₃ or more, the asynchronous injection which has been stopped until then can be performed again.

In the present embodiment configured as described above, the state of the constant voltage Vsub which is the power supply voltage of the microprocessor 70 is set to w.
When the voltage is monitored by the i signal output unit 95 and is equal to or higher than the voltage (here, the determination voltage V ₁ ) that does not cause a problem in restarting the operation of the microprocessor 70, a predetermined value t ₂ , where t ₂ is the cooling water temperature of the internal combustion engine. Since the time is adjusted according to the cooling water temperature, of course, the asynchronous fuel injection peculiar to the start at the cumulative pulse width of 50 msec is executed. Therefore, even when the constant voltage Vsub fluctuates including a voltage range in which the operation of the microprocessor 70 cannot be guaranteed at the time of starting, asynchronous fuel injection at the time of starting immediately starts when the constant voltage Vsub becomes equal to or higher than the determination voltage V _1. Therefore, reliable fuel injection at the time of starting can be expected, and inhalation of the combustible mixture into the cylinder becomes reliable.
The startability of the internal combustion engine 1 is enhanced.

Further, even when the constant voltage Vsub becomes lower than the judgment voltage V _{2 and} the init signal in the power supply circuit 60 is output and the microcomputer 50 is reset, the constant voltage Vsub recovers and the judgment voltage Vsub is restored. If V ₁ or more, asynchronous start-time fuel injection is performed by the fuel injection control signal τ ₂ without waiting for main fuel injection performed by calculating the fuel injection time from the rotation speed Ne of the internal combustion engine 1 and other parameters. Therefore, if the starter 32 can rotate,
The intake of fuel into each cylinder of the internal combustion engine 1 can be ensured.

Further, in this embodiment, only a few electric circuits are added, and the fuel injection is always controlled under the single microprocessor 70, so that the start injector and its fuel system are not required. Instead, it is possible to reliably perform fuel injection at the time of starting with a simple configuration.

In this embodiment, the constant voltage Vsub is always lower than the judgment voltage V ₂ and the microprocessor 70 controls the ignition timing control signal ig.
Backup circuit 56 when synchronization is reached.
Thus, the ignition timing and fuel injection of the internal combustion engine 1 are controlled, and it can be said that the startability of the internal combustion engine 1 in the voltage range in which the starter 32 is driven is almost complete.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment, and it goes without saying that the present invention can be implemented in various modes without departing from the scope of the present invention.

EFFECTS OF THE INVENTION As described in detail above, according to the electronic fuel injection control device of the present invention, it is possible to realize a reliable fuel injection at the time of start-up without the need for a start injector and its fuel system. The excellent effect that the startability of the internal combustion engine 1 can be sufficiently ensured. Further, since the structure can be simplified, the problems of the reliability of the device, the labor of the manufacturing process, the cost, etc. are improved. Furthermore, it is possible to prevent fuel fogging due to repeated asynchronous injections,
If the starter-off period is longer than the time required to eliminate the fuel fog, restarting the asynchronous injection can prevent the startability from being impaired.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of the present invention, FIG. 2 is a schematic configuration diagram showing a configuration of an internal combustion engine and its peripheral devices as an embodiment of the present invention, and FIG. 3 is a configuration of an electronic control circuit 2. Block diagram, FIG. 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, and FIG. 6 is an example of ignition timing and fuel injection control by the backup circuit 56. 7 is a timing chart showing
FIG. 8 is a circuit diagram showing the configuration of the power supply circuit 60, FIG. 8 is a flow chart of a 4 msec interrupt routine showing a control example in the embodiment, and FIG. 9 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 ... Electromagnetic fuel injection valve 29 ... Ignition switch 31 ... Starter switch 32 ... Starter 50 ... Microcomputer 60 ... Power supply circuit 70 ... Microprocessor (MPU) 73 ... RAM 82 ... RS flip-flop 86 ... wi signal detection circuit 95 ... wi signal output unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location F02D 45/00 376 E 7536-3G

Claims (2)

[Claims] 1. An operating condition detecting means for detecting an operating condition of an internal combustion engine, a fuel injecting means for injecting fuel into the internal combustion engine, and a fuel injection amount calculated based on the detected operating condition of the internal combustion engine. A fuel injection control means for controlling the fuel injection means to inject main fuel in synchronization with the rotation of the internal combustion engine; and an electronic fuel injection control device comprising: A power supply voltage monitoring unit that detects that the power supply voltage is higher than or equal to a predetermined voltage for ensuring operation, and the fuel injection during the starter operation period in which the power supply voltage is higher than or equal to the predetermined voltage based on a detection signal from the power supply voltage monitoring unit. Asynchronous injection means for performing asynchronous injection by means, and when the asynchronous injection time by this asynchronous injection means is accumulated, and when the power supply voltage is below the predetermined voltage,
Timer means for storing the accumulated time, asynchronous injection stop means for stopping the asynchronous injection when the accumulated time of the timer means exceeds a predetermined time determined according to the detected operating condition, the starter Stop detecting means for detecting an operation stop of the starter, a measuring means for measuring an elapsed time from the stop of the starter operation, and an initializing means for initializing the accumulated time when the elapsed time reaches a predetermined time. An electronic fuel injection device characterized by the above. 2. The electronic fuel injection control device according to claim 1, wherein the predetermined time for stopping the asynchronous fuel injection at the time of starting is determined by the cooling water temperature of the internal combustion engine.