JPH068619B2 - Fuel injection control device for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device for controlling a fuel injection device installed in an internal combustion engine mounted on a vehicle, particularly an automobile, and more particularly to a fuel injection device when starting the engine. The present invention relates to a fuel injection control device for an internal combustion engine that can reliably control the fuel injection.

[Conventional technology]

Conventionally, it has been known that engine startability is improved by driving an asynchronous injection or a starting electromagnetic fuel injection valve at the time of starting the internal combustion engine to increase a predetermined amount of fuel,
JP-B-47-42410 and JP-A-48-1042
Japanese Patent No. 5 discloses means for increasing the amount of fuel.

On the other hand, in recent years, as a fuel injection control device, a device using a microcomputer has become mainstream due to demands for improved functions and the like.

Then, the microcomputer of the fuel injection control device
Normally, when the ignition switch is turned on and the battery voltage is applied to the microcomputer, the reset state of the microcomputer is released, the ports, RAM, etc. are initialized and a predetermined program is executed. The operation control of the fuel injection device is started.

However, the above-mentioned microcomputer may not be able to reliably determine the starting state of the engine. Therefore, the asynchronous injection at the time of start and the drive of the electromagnetic fuel injection valve for start may be performed only once at the start. It may be performed once or not at all, resulting in extremely poor startability. That is, as shown in FIG. 4, when the ignition switch (IGSW) is turned on, the microcomputer of the fuel injection control device is reset and the CPU in the microcomputer is also reset. After releasing this reset, or when the starter signal is turned on, a pulse signal for instructing emergency synchronous injection (or driving of the electromagnetic fuel injection valve for starting) is generated once. When the battery voltage falls below the CPU operating voltage, the CPU is reset, and when the battery voltage rises above the CPU operating voltage again, the reset of the CPU is released, and a pulse signal for instructing asynchronous injection is generated accordingly. Then, the asynchronous injection is frequently generated (conventional injection A). Therefore, there is a possibility that the fuel supply will become excessive and the spark plug will be covered with fuel and will not be ignited, making it impossible to start the engine. In order to prevent this, after the ignition switch is turned on and the reset of the microcomputer is released, it is confirmed that the engine is stopped by a signal from a rotation speed sensor or the like, and then a pulse signal for instructing asynchronous injection is set to 1 There is one configured to generate once, but in this case a pulse signal for instructing asynchronous injection may not be generated if the time from turning on the ignition switch to turning on the starter is short,
Asynchronous injection may not be performed (conventional injection B).

[Problems to be solved by the invention]

The problem to be solved by the present invention is, as described above,
In the fuel injection control device using the microcomputer,
The point is that there is a risk of malfunction when the engine is started.

Therefore, an object of the present invention is to provide a fuel injection control device for an internal combustion engine having a configuration that reliably determines the starting state of the engine and prevents the occurrence of malfunctions when starting the engine.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides a microcomputer that is reset when the power supply voltage becomes equal to or lower than the operating voltage and is reset when the power supply voltage becomes equal to or higher than the operating voltage, as shown in FIG. The microcomputer includes various parameters of the internal combustion engine as input signals, arithmetic means for outputting a pulse signal having a pulse width calculated according to the input signals to the electromagnetic fuel injection valve, and various parameters of the internal combustion engine. And a determining means for determining whether or not the engine is in a starting state by using a part of the above, and while the determining means determines that the engine is in the starting state, even if the power supply voltage becomes equal to or lower than the operating voltage, Storing means for storing the starting state, and canceling the starting state stored in the storing means when the determining means determines that the starting state is not the starting state. The fuel injection control device for an internal combustion engine includes a releasing means and a control means for instructing the arithmetic means to start fuel injection when the starting state stored in the storage means reaches a predetermined state.

〔Example〕

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

FIG. 1 is an overall configuration diagram, and 1 is a known 4-cycle spark ignition type internal combustion engine (hereinafter referred to as “engine”), which sucks fuel air through an air cleaner 2, an intake pipe 3, and a throttle valve 4. Further, the fuel is supplied from a fuel system (not shown) via an electromagnetic fuel injection valve 5 installed corresponding to each cylinder and an electromagnetic fuel injection valve 9 for cold start which operates at cold start. The exhaust gas after fuel is discharged to the atmosphere through the exhaust manifold 6, the exhaust pipe 7, the tertiary catalytic converter 8 and the like. In the intake pipe 3, a potentiometer-type intake air amount sensor 10 that detects the intake air amount taken into the engine 1 and outputs an analog voltage signal corresponding to the intake air amount, and the temperature of the intake air is detected and the intake air temperature is detected. A thermistor type intake air temperature sensor 11 that outputs an analog signal is installed. Also,
The thermistor-type water temperature sensor 1 that detects the cooling water temperature in the engine 1 and outputs an analog voltage signal according to the cooling water temperature
2 is installed. Further, the exhaust manifold 6 detects the air-fuel ratio from the oxygen concentration in the exhaust gas, and outputs a high level signal when the air-fuel ratio is richer than the theoretical air-fuel ratio and a low level signal when the air-fuel ratio is leaner than the theoretical air-fuel ratio. An air-fuel ratio sensor 13 that outputs a level signal is installed. A thermistor-type exhaust temperature sensor 14 that detects the exhaust temperature is installed in the exhaust pipe 7. 15
Is a rotation speed sensor that detects the rotation speed (rotation speed) of the crankshaft of the engine 1. For example, a pickup coil is arranged so as to face a timing rotor axially attached to the rotor in the distributor 16, and It outputs a pulse signal with a frequency corresponding to the rotation speed. Reference numeral 17 denotes a throttle sensor that detects the throttle opening of the throttle valve 4, and outputs a signal indicating, for example, an idle state when the throttle valve 4 is fully closed. An igniter 18 has a built-in ignition coil, which interrupts the primary current of the ignition coil at a controlled timing to generate a high voltage on the secondary side thereof, and the high voltage is supplied to each ignition plug of the engine cylinder via a distributor 16. Apply to. Reference numeral 19 denotes a STA terminal connected to a starter (not shown), which detects an ON state of the starter and outputs a pulse signal corresponding to the ON time.

The fuel injection control device 20 includes sensors 10 to 15 and 1
7 and a fuel injection amount based on a detection signal from a STA terminal 19 connected to a starter (not shown), and the valve opening time of the electromagnetic fuel injection valves 5 and 9 is controlled according to the injection amount.

The fuel injection control device 20 is equipped with a microcomputer 20a. FIG. 2 shows a main part configuration of the fuel injection control device 20.

Reference numeral 100 is a CPU that executes various arithmetic control processes according to a predetermined program, and 101 is a rotation speed counter that receives a detection signal from the rotation speed sensor 15 and counts the engine rotation speed. An interrupt control unit 102 inputs an interrupt command signal sent from the number-of-times counter 101 in synchronization with the engine rotation, and at this time, the interrupt signal is sent to the CPU 10.
Output to 0. Reference numeral 103 denotes a digital input port, which inputs digital signals from the air-fuel ratio sensor 13, the throttle sensor 17, and the STA terminal 19 and transmits them to the CPU 100. 1
Reference numeral 04 denotes an analog input port including an analog multiplexer and an A / D converter, which A / D-converts the detection signals from the intake air amount sensor 10, the intake air temperature sensor 11, the water temperature sensor 12, and the exhaust gas temperature sensor 14 to sequentially perform CPU 100. It has the function of transmitting to.

Reference numeral 105 is a power supply circuit directly connected to the battery 21,
Power is supplied to the AM 106, and 107 is a power supply circuit connected to the battery 21 via the ignition switch 22, which supplies power to each unit other than the RAM 106.
The RAM 106 is a readable and readable temporary storage circuit, but forms a non-volatile memory that always retains stored contents even after the ignition switch 22 is turned off. A read-only ROM 108 stores a program, various constants, table data, and the like.

The output circuits 109 and 110 are composed of latches, down counters, power transistors, etc.
Generates a control signal for controlling the actual opening time of the fuel injection valve 5 based on the fuel injection amount (time) data calculated by the CPU 100, and outputs the control signal to the fuel injection valve 5 at a predetermined timing. Further, the output circuit 110 creates a control signal for controlling the spark time of the spark plug based on the ignition timing data calculated by the CPU 100, and outputs it to the igniter 18 at a predetermined timing. A timer 111 generates a clock signal and sends it to the CPU 100, or outputs a time interrupt signal to the interrupt controller 102.

Further, the fuel injection control device 20 is provided with a control circuit 200 for controlling the cold start electromagnetic fuel injection valve 9.
It operates in response to a signal from the STA terminal 19 only once during cold start.

Further, 150 is a signal sent to the CPU 100 and C
It is a system bus that is a transmission path for signals sent from the PU 100.

Next, an operation example of the fuel injection control device 20 will be described with reference to the schematic flow chart of the CPU 100 shown in FIG.

First, the power switch 10 is turned on by the ignition switch 22.
When power is supplied to 7, the main routine is started in step 1000, and in step 1001, the port 103,
The 104, the RAM 106 and the like are initialized. At this time, the flag FSTA indicating the starting state stored in the RAM 106 is set so as to maintain the state before the CPU 100 was reset last time. Step 1002
Then, the starting state of the engine 1 is determined. This determination is
Normally, the rotation speed of the engine 1 is a set value (for example, 100 r.p.
m.) and the following and the fact that a pulse signal indicating that the starter of the STA terminal 19 connected to the starter is in the ON state is output, and the like. If it is determined in step 1002 that the engine is not in the starting state, the process proceeds to step 1004, FSTA is set to 0, and the process proceeds to step 1010. If it is determined that the engine is in the starting state, the process proceeds to step 1003, and in step 1003 the RAM 106
It is determined whether the FSTA stored inside is 1 or not. Here, if FSTA is 1, the process proceeds to step 1010, but if FSTA is 0, the process proceeds to step 1005 to calculate the asynchronous injection amount of the fuel injection valve 5 according to the engine parameter, and to the output circuit 109. Is output to the fuel injection valve 5 from the output circuit 109 to control the valve opening time of the fuel injection valve 5 according to this injection amount, and the fuel injection valve 5 performs asynchronous injection according to the control signal. Run. Then, the process proceeds to step 1006, sets FSTA to 1, and proceeds to step 1010. In step 1010, the ignition time is calculated using a predetermined calculation method and sent to the output circuit 110, and a control signal for controlling the spark plug spark time is output from the output circuit 110 to the igniter 18 at a predetermined timing. Then, the injection amount according to the state of the normal engine 1 is calculated and the output circuit 1 is calculated.
09, and a control signal is output from the output circuit 109 so that fuel injection is performed from the fuel control valve 5 at a predetermined timing synchronized with the rotation of the engine 1. After that, the process returns to step 1002 and the above-mentioned routine is repeated.

In the above routine, if the engine 1 is stopped by turning off the ignition switch 22, step 1004
The state in which FSTA is set to 0 is stored in the RAM 106, and the asynchronous injection is surely performed only once at the next start. This is determined in step 1002 to be the starting state, and since FSTA is 0 in step 1003, the process proceeds to step 1005, the aforementioned asynchronous injection is performed in step 1005, FSTA is set to 1 in step 1006, and step 1010, The process proceeds to 1011 and returns to step 1002. When returning to step 1002, if the engine is not in the starting state, that is, if the engine 1 is at the predetermined speed or higher or the starter is off, proceed to step 1004.
Even if the STA is set to 0, the process proceeds to step 1010 and thereafter, and even if it is determined again in step 1002 that the engine is in the starting state and the process proceeds to step 1003, step 100
Since FSTA is stored as 1 in step 3, step 10
This is because the process bypasses 05 and 1006 and proceeds to step 1010 and thereafter.

By the way, when the voltage of the battery 21 is lowered due to the load of the starter or the like during starting and the CPU 100 is reset, asynchronous injection is performed in step 1005 and FSTA is set to 1 in step 1006 and RA
After being stored in M106, FSTA is set to 1 and R
Since it is stored in AM106, after reset release,
Even if the main routine is started again in step 1000 and it is determined in step 1002 that the engine is in the starting state, it is determined that step 1003 bypasses steps 1005 and 1006 and proceeds to step 1010 because FSTA is stored as 1. Therefore, the asynchronous injection at the time of starting the fuel injection valve 5 is executed only once from when the ignition switch 22 is turned on to when it is turned off.

Therefore, when the startability is affected by the asynchronous injection of the fuel injection valve 5 in a temperature state in which the fuel injection valve 9 for cold start does not operate, the asynchronous operation after the resetting of the CPU 100 is released from the above facts. Since the injection can be prevented and the asynchronous injection is surely executed once, the amount of fuel supplied to the engine 1 at this time is regulated to a predetermined amount, and there is no possibility of starting due to overfuel supply, and the startability is improved. To do.

Next, another operation example of the fuel control device 20 will be described with reference to the schematic flowchart of the CPU 100 shown in FIG.

First, in step 2000, the main routine is started, and in step 2001, the ports 103 and 104 and the RAM 106 are started.
Etc. are initialized. At this time, while the signal in which the starter in the RAM 106 is on is sent from the STA terminal 19, the CSTA that stores the number of times this routine is repeated is set to maintain the state before the CPU 100 was reset last time. I am doing it. And step 2
At 02, it is determined whether or not the starter is in the on state by the signal from the STA terminal 19. If it is in the on state, 1 is added to CSTA in step 2003, and if it is in the off state, CSTA is set to 0 in step 2004. Together, go to step 2005. CST in step 2005
It is determined whether the value of A matches the predetermined value T, and when it matches, the process proceeds to step 2006, the asynchronous injection is calculated and executed as described above, and otherwise, the process bypasses step 2006 and proceeds to step 2010 and thereafter. . Note that step 201
0, step 2011, as in step 1010 and step 1011 shown in FIG. 3 (a), the normal calculation of ignition timing and injection amount is executed. And, for example, step 2
When passing from 002 to step 2011 in 4ms, if the predetermined value T is set to 25, it will be about 100 after the starter is turned on.
Asynchronous injection is executed after ms. Even if the CPU 100 is reset 100 ms after the starter is turned on, the value of CSTA immediately before the CPU 100 is reset is maintained in the RAM 106, and therefore, even after the reset of the CPU 100 is released. The value of CSTA is continuously increased, the asynchronous injection is performed when CSTA reaches the predetermined value T (= 25) after the reset state of the CPU 100, and CSTA continues to increase while the starter is on. Then, CSTA is set to 0 when the starter is turned off. Therefore, when the ignition switch 22 is normally turned off and the CPU 100 is reset, 0 is stored in CSTA. Asynchronous injection, while the starter is driving
That is, while the signal indicating the starter on of the STA terminal 19 is being sent to the digital input port 103, it is driven only once and is not driven twice during that time.

Therefore, when the startability is affected by the asynchronous injection of the fuel injection valve 5 in a temperature state in which the fuel injection valve 9 for cold start does not operate, the CSTA is always stored in the RAM 106 according to the value of CSTA. The asynchronous injection is executed only when the value of has reached the predetermined value T, and as in the case of the flowchart of FIG. 3 (a) described above, there is no extra asynchronous injection, and one asynchronous The injection is executed and the amount of fuel supplied to the engine 1 is regulated to a predetermined amount, so that the engine is never incapable of starting due to excessive fuel supply, and the startability is improved. Further, in order to surely execute the asynchronous injection only in the engine start state, a start determination (not shown) is performed before step 2002, and when it is not in the start state, step 2004 is performed, and when it is in the start state, step 200 is performed.
3 is set, and if the determination of the starting state that is determined by the signal of the STA terminal 19 and the number of revolutions of the engine 1 at the time of initialization in step 2001 is set as the starting state in advance, the number of revolutions of the engine 1 is set. Value, eg 10
It is possible to save the time used for the determination of the starting state including the determination that it is 0 rpm or less, the asynchronous injection can be executed at an early timing, and even if the starter is turned on immediately after the ignition switch 22 is turned on. Since it is determined in advance that the engine is in the starting state, the above-described flow is immediately executed and the asynchronous injection is performed.

Next, still another operation example of the fuel injection control device 20 will be described with reference to the schematic flowchart of the CPU 100 shown in FIG.

First, the main routine is started in step 3000,
In step 3001, the ports 103 and 104 and the RAM 10
6th grade is initialized. At this time, the RAM 106
While the signal that the internal starter is on is sent from the STA terminal 19, the CSTA that stores the number of times this routine is repeated is set to maintain the state before the CPU 100 was reset last time. Further, the operation determination flag FSTj of the fuel injection valve 9 for cold start is set to 1 in advance. Steps 3002, 3003, 300
In step 4, steps 2002 and 2 shown in FIG.
As in 003 and 2004, the number of times this routine is repeated is stored in CSTA while the starter is on, and CSTA is set to 0 when the starter is off.
Further, even if the CPU 100 is reset when the starter is on and is initialized again in step 3001 after the reset is released, the CSTA maintains the value immediately before the reset of the CPU 100, so that the CSTA value continues to increase. In step 3005, CSTA
It is determined whether the value of has reached the predetermined value T ₁ . When the predetermined value T ₁ is reached, it is determined in step 3006 that the operation determination flag FSTj of the fuel injection valve 9 for cold start is 1, and when FSTj = 1, the process proceeds to step 3007 to perform cold start. The fuel injection valve 9 for time is operated, and a predetermined signal is output to the control circuit 200 via the output circuit 109. In response to this, the control circuit 200 drives and controls the fuel injection valve 9 for cold start. To be done. When the predetermined process is performed in step 3007, FSTj is set to 0 in step 3008 and the process proceeds to step 3010.
11, the step 1010 shown in FIG.
Similar to 1011, the normal calculation of ignition timing and injection amount is executed. In step 3005, the value of CSTA is the predetermined value T
₁ does not match, or FSTj in step 3006
If 0 is 0, both bypass steps 3007 and 3008 and proceed to step 3010. Then, for example, in the same manner as the routine shown in FIG. 3 (b) described above, if the predetermined value T ₁ is set to 4 assuming that the steps 3002 to 3011 are passed in 4 ms, the starter is turned on. About 16 ms after that, the fuel injection valve 9 for cold start is driven. Even if the CPU 100 is reset during this period, the value of CSTA increases while the CPU 100 is being reset, so after the time that the CPU 100 is reset and the time that is 16 ms has elapsed, That is, the value of CSTA is the predetermined value T ₁ (= 4)
Then, the fuel injection valve 9 is driven. Even if the CPU 100 is reset after the fuel injection valve 9 in the cold start time is driven and is initialized again in step 3001 and FSTj is set to 1, the value of CSTA is set to a predetermined value when the starter continues to be turned on. The value is larger than the value T ₁ , and CSTA is 0 if the starter is off.
In any case, since NO is determined in step 3005 and steps 3006, 3007 and 3008 are bypassed, the fuel injection valve 9 for cold start is operated while the starter is driven, that is, at the STA terminal 19. It operates only once while the signal indicating starter-on is being sent to the digital input port 103, and does not operate more than once during this period. Then, as described in the operation example of FIG. 3 (b), it may be set in advance that the engine is in the starting state at the time of initialization in step 3001. In the cold start, the control circuit 200 preferentially executes the control for the cold start on the fuel injection valve 9 for the cold start.

Therefore, when fuel is supplied to the engine 1 at the time of full start using the fuel injection valve 9 for cold start, the CSTA that is always stored in the RAM 106 as described above except during cold start.
Since the operation is controlled so that the fuel injection valve 9 for cold start is driven only when the value of CSTA reaches the predetermined value T ₁ by the value of, the fuel injection valve 9 can be driven only once. However, if the amount of fuel supplied at this time is defined to be a predetermined amount, it will never be impossible to start due to excessive fuel supply, and the startability will be improved.

In each of the above operation examples, the asynchronous injection of the fuel injection valve 5 and the cold injection fuel injection valve 9 have been described, but a predetermined amount of fuel to the engine 1 at the time of start is described. The supply may be performed using both.

Further, in the above-described embodiment, the RAM 106 is directly connected to the battery 21.
The non-volatile memory which is backed up by the power supply circuit 105 connected to
A non-volatile memory that always retains stored contents without using a backup may be used.

Further, in the above-described embodiments, the present apparatus is applied to the L-JETRO system, but it is applicable to the D-JETRO system and other systems in which the engine 1 is controlled by the microcomputer.

〔The invention's effect〕

As described above, in the present invention, when the internal combustion engine is not started and the engine is tried to be started many times, the determining means determines that the internal combustion engine is not in the starting state each time, and the starting state stored in the storage means. Is released, and each time, the fuel injection for starting is executed when the starting state becomes a predetermined state,
Even if the starting operation fails once, the starting operation can be repeated, and even when the power supply voltage drops below the operating voltage of the microcomputer, the starting state obtained from the determining means is continuously stored in the storage means. Fuel injection processing for the internal combustion engine becomes reliable,
There is an excellent effect that the start failure of the internal combustion engine due to this can be prevented and the startability of the internal combustion engine can be remarkably improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing a main part of the embodiment of the present invention, and FIG. 3 (a) shows an operation example of the embodiment of the present invention. Flow chart, Figure 3
(b) is a flow chart showing another operation example of the embodiment of the present invention, FIG. 3 (c) is a flow chart showing still another operation example of the embodiment of the present invention, and FIG. 4 is an operation by the conventional apparatus and the book. FIG. 5 is a time chart showing the operation according to the flowchart shown in FIG. 3 (b) according to the embodiment of the invention, and FIG. 5 is a schematic configuration diagram of the present invention. 1 ... Internal combustion engine, 5 ... Electromagnetic fuel injection valve, 9 ... Electromagnetic fuel injection valve for cold start, 19 ... STA terminal, 20
... Fuel injection control device, 20a ... Microcomputer, 100 ... CPU, 106 ... RAM.

Claims (1)

[Claims] 1. A microcomputer is provided which is reset when a power supply voltage becomes equal to or lower than an operating voltage and is reset when the power supply voltage becomes equal to or higher than an operating voltage. The microcomputer has various parameters of an internal combustion engine as input signals, A calculating means for outputting a pulse signal having a pulse width calculated according to the input signal to the electromagnetic fuel injection valve, and a determining means for determining whether or not the engine is in a starting state by using some of various parameters of the internal combustion engine. While the determining means determines that the engine is in the starting state, the storing means stores the starting state obtained from the determining means even if the power supply voltage becomes equal to or lower than the operating voltage, and the determining means does not indicate the starting state. When it is determined that the starting state stored in the storage unit is released, the starting state stored in the storage unit is in a predetermined state. The fuel injection control device for an internal combustion engine and a control means for commanding the fuel injection for starting the operation means when it has.