JP2855962B2 - Fuel injection device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device for supplying fuel to an internal combustion engine.

[0002]

2. Description of the Related Art In order to operate an internal combustion engine in an optimum state, it is important to properly control the air-fuel ratio in accordance with the temperature, rotation speed, etc. of each part of the engine. When fuel is supplied to the engine by the injector, the amount of fuel injection is determined by the time during which fuel is injected from the injector (fuel injection time) and the pressure of the fuel applied to the injector. Also, since the air-fuel ratio is affected by temperature and atmospheric pressure, it is necessary to accurately control the fuel injection time according to control conditions such as atmospheric pressure and the temperature of each part to control the air-fuel ratio accurately. It is.

[0003] Therefore, using a microcomputer,
Atmospheric pressure, ambient temperature, engine temperature, engine speed,
2. Description of the Related Art A fuel injection device that controls the supply of a drive current to an injector in accordance with a throttle opening and the like to control a fuel injection time is used.

In this type of fuel injection device, a microcomputer calculates an appropriate fuel injection time at the time of starting the internal combustion engine, and after completion of the starting, information such as atmospheric pressure and temperature given from a sensor and a signal. Using the output of the generator as an input, a fuel injection position (a rotational angle position at which fuel injection is started) and a fuel injection time are calculated, and an injection command including information on the calculated fuel injection time at the calculated fuel injection position. Output a signal. The injection command signal is, for example, a signal having a rectangular waveform rising at the fuel injection position and having a signal width equal to the fuel injection time. This injection command signal is given to the injector drive circuit. The injector drive circuit supplies a drive current to the injector while the injection command signal is being given. The injector opens its valve and injects fuel while the drive current is applied.

[0005]

When the internal combustion engine that has been initially started is once stopped and then restarted, if the engine is supplied with fuel having the same air-fuel ratio as that at the time of the initial startup, the restart of the internal combustion engine is stopped. In such a case, the amount of fuel may become excessive and the spark plug may be caught, and the engine may not be able to be started.

[0006] In this specification, "initial start" means starting the engine after leaving it stopped for a long time, and "restarting" means stopping the engine that has been initially started after temporarily stopping it. Starting the engine immediately, or without too much time. In order to solve the above-described problem, the fuel supply amount may be reduced when the engine is restarted.However, conventionally, control for switching the fuel injection amount between the initial start and the restart is performed. Had not gone. In particular, when the fuel injection device is applied to an engine without a battery, the microcomputer is operated using a generator driven by the engine as a power source. In this case, the microcomputer establishes the voltage of the generator. To start the predetermined calculation after the start of the internal combustion engine,
It cannot be determined whether it is an initial start or a restart. Therefore, in a fuel injection device that operates a microcomputer using a generator driven by the engine as a power source, the amount of fuel injection must be the same both at the time of initial startup and at the time of restart, and the startability of the engine at the time of restart is inevitable. Was inevitable to get worse.

An object of the present invention is to provide a fuel injection device for an internal combustion engine which can smoothly restart the engine when a microcomputer is operated using a generator driven by the internal combustion engine as a power supply. To provide.

[0008]

According to the present invention, there is provided an injector for injecting fuel when a drive current is applied, and a fuel injection time suitable for starting the internal combustion engine when the engine is started. A microcomputer that calculates a fuel injection time suitable for operation based on various control conditions and generates an injection command signal including information on the calculated fuel injection time, and a fuel injection time given by the injection command signal. The present invention relates to a fuel injection device for an internal combustion engine having an injector drive current supply control circuit for supplying a drive current to the inter-injector. Here, the microcomputer operates using a generator driven by the internal combustion engine as a power supply.

In the present invention, an ignition confirmation means for confirming ignition of the engine when the internal combustion engine is started, a charge accumulation circuit for accumulating electric charge in the charge accumulation element when ignition of the engine is confirmed by the ignition confirmation means, A discharge circuit for discharging the charge stored in the charge storage element with a sufficiently large time constant; and an initial start signal when a predetermined amount of charge is not stored in the charge storage element, and a predetermined amount of charge in the charge storage element. And an initial start / restart signal generating circuit for generating a restart signal when is stored. The microcomputer calculates a fuel injection time suitable for the initial start when the initial start signal is generated when the internal combustion engine is started, and calculates a fuel injection time suitable for the restart when the restart detection signal is generated. Calculate.

In the present invention, "at the time of steady operation" means an operation state after the engine is started (an operation state other than at the time of start), and includes a warm-up operation state and an idling state.

[0011]

In the above-described fuel injection device, when the internal combustion engine is initially started, the electric charge is not stored in the electric charge storage element, so that the initial start restart signal generating circuit generates the initial start signal. Therefore, the microcomputer calculates a suitable fuel injection amount at the time of the initial start of the internal combustion engine, and smoothly starts the engine.

When the engine is stopped and restarted after the engine is initially started, since the charge accumulated in the charge storage element at the time of the initial start is sufficiently remaining, the initial start restart signal generating circuit is provided. A restart signal has been generated. At this time, the microcomputer calculates a fuel injection time suitable for restarting, so that the amount of fuel supplied to the engine does not become excessive, and the engine is restarted smoothly.

[0013]

1 shows an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a signal generator which is driven by an internal combustion engine and generates a signal at a predetermined rotational angle position of the engine. The signal generator 1 includes a rotor 1 mounted on a rotating shaft of an engine.
This is a well-known inductor-type generator consisting of A and a signal generator 1B. A rotor 1A is provided with a reluctor 1a. The signal generator 1B has a signal coil 1b wound around an iron core having a magnetic pole portion facing the rotor, and a permanent magnet that generates a magnetic flux linked to the signal coil. A pulse-like signal having a different polarity is induced in the signal coil 1b when opposing and when the opposition ends.

Reference numeral 2 denotes an injector having a needle valve for opening and closing the nozzle and an electromagnet for opening and closing the valve. Fuel is supplied to this injector at a predetermined pressure from a fuel pump. The injector 2 has a drive coil 2a that excites an electromagnet, and injects fuel by opening a valve while a drive current is applied to the drive coil.

Reference numeral 3 denotes an injector drive circuit for supplying a drive current to the drive coil 2a of the injector while the drive signal Vd is being input. This drive circuit comprises a switch circuit that closes only while the drive signal is being supplied.

Reference numeral 4 denotes a microcomputer, which is obtained from various control conditions (throttle angle, engine temperature, etc.) obtained from outputs of various sensors attached to the internal combustion engine and output signals from a signal generator. Based on the rotation angle information and the speed information, when starting the internal combustion engine, calculate a fuel injection time and a fuel injection position suitable for starting,
After the start is completed, the fuel injection time and the injection position suitable for the steady operation are calculated based on various control conditions. Then, a signal including information on the calculated fuel injection time and fuel injection position is generated from the output port A1 as a soft control injection command signal Vs. The soft control injection command signal Vs generated by the microcomputer 4 is, for example, a signal whose signal width corresponds to the fuel injection time and whose rising position corresponds to the fuel injection position.

Reference numeral 6 denotes a waveform shaping circuit for converting an output signal of the signal generator 1 into a rectangular wave signal. The rectangular wave signal obtained from the waveform shaping circuit is supplied to an input port B 1 of the microcomputer 4 as a signal for providing rotation angle information. And to the hardware control injection command signal generation circuit 7.

The hardware control injection command signal generation circuit 7
Rise in the injection position of the low speed of the engine in synchronism with the output signal of the signal generator 1, and a low-speed Tokiwa over de control injection command signal Vhi having a signal width corresponding to the injection time suitable for low speed, the engine steady rise in the injection position of the driver, it generates a steady Tokiwa over de control injection command signal Vhn having a signal width corresponding to the injection time suitable for steady-state operation. Slow Tokiwa over de signal width of the control injection command signal Vhi is intended to be set to provide the fuel required to maintain the rotation of the engine during low-speed engine, the injection command for slow Tokiwa over de control The fuel injection amount given by the signal Vhi is set to be equal to or less than the fuel injection amount required at the time of restart.

The hardware control injection command signals Vhi and Vhn are given to a switching circuit 9 through a signal selection circuit 8.

In this embodiment, a magnet generator 10 is mounted on an engine for driving the microcomputer 4 and the injector drive circuit 3. This magnet generator includes a magnet rotor 10a attached to a rotating shaft of an engine and a stator having power generation coils 10b and 10c, and outputs of the power generation coils 10b and 10c are supplied to a power supply circuit 11 respectively.
And 12 have been entered.

The power supply circuits 11 and 12 are DC constant voltage circuits for rectifying the AC output of the power generation coils 10b and 10c and outputting a DC constant voltage, respectively. The DC voltage obtained from the power supply circuit 12 is applied to a power supply terminal of the injector drive circuit 3.

The signal selection circuit 8 selects the low-speed hard control injection command signal Vhi when the internal combustion engine is low and outputs it as a hard control injection command signal Vh. And outputs it as the hard control injection command signal Vh.

The signal selection circuit 8 may select a signal by operating a manual switch, or may select a signal by a switch that automatically operates when a microcomputer malfunctions. In addition, the engine speed is detected, and when the engine speed is lower than the set value, the low-speed hard control injection command signal Vhi is automatically selected. When the engine speed exceeds the set value, the steady-state hard control The injection command signal Vhn may be automatically selected.

The microcomputer 4 also has an output port A2. When the induced voltage of the power generation coil 10b is established and the microcomputer 4 is operating normally, the microcomputer 4 outputs a switching signal Ve from the output port A2 to generate power. The output of the switching signal Ve is stopped when the induced voltage of the coil 10b is low, the power supply voltage of the microcomputer 4 is insufficient and the microcomputer cannot operate, or when the operation of the microcomputer becomes abnormal. It has become. The detection that the operation of the microcomputer has become abnormal can be performed by a known method in which a program for checking is incorporated in a program for operating the microcomputer. In this embodiment, the switching signal generating means is realized by software for operating the microcomputer 4.

The switching signal Ve is supplied to the switching circuit 9 via the switching signal supply control circuit 13. The switching signal supply control circuit 13 allows the switching signal Ve to be given to the switching circuit 9 when the signal selection circuit 8 is selecting the low-speed hard control injection command signal Vhi. When the hardware control injection command signal Vhn is selected, the switching signal Ve is prohibited from being given to the switching circuit. The switching signal supply control circuit 13 closes when the signal selection circuit 8 selects the low-speed hard control injection command signal Vhi and opens when the steady-state hard control injection command signal Vhn is selected. It can be configured by a switch that operates in conjunction with the selection operation of the circuit 8.

The switching circuit 9 supplies a signal having the same waveform as the hard control injection command signal Vh output from the selection circuit 8 as a driving signal Vd to the injector driving circuit when the switching signal Ve is not supplied. Is given, the drive signal V has the same waveform as the soft control injection command signal Vs output from the microcomputer.
This is given to the injector drive circuit 3 as d.

In this embodiment, an initial start / restart detecting circuit 20 is also provided. This detection circuit 20 can be configured, for example, as shown in FIG. In FIG. 2, reference numeral 21a denotes a charge storage element comprising a capacitor.
One end of a is grounded, and the other end is connected to the cathode of a diode 21c through a resistor 21b. Diode 2
1c is connected to the collector of the PNP transistor 21d, and the emitter of the transistor is connected to the power supply circuit 11d.
Output terminal. The base of the transistor 21d is connected to the output port A3 of the microcomputer 4 through a resistor 21e, and a resistor 21f is connected between the base and the emitter of the transistor. A resistor 22 having a sufficiently large resistance value is provided at both ends of the charge storage element 21a.
a is connected.

A non-ground side terminal of the charge storage element 21a has a field-effect transistor (FET) 23a having a grounded source.
And the drain of the field-effect transistor is connected to the input port B2 of the microcomputer 4 and to the output terminal of the power supply circuit 11 through the resistor 23b.

The microcomputer 4 realizes ignition confirmation means for confirming ignition (explosion) of the internal combustion engine. The microcomputer 4 sets the potential of the output port A3 to zero (or low level) and outputs an ignition confirmation signal when the ignition of the engine is confirmed at the start of the engine.

When the ignition is performed at the time of starting the engine, the rotation speed of the engine shows a rapid increase at that moment. Therefore, the above-mentioned ignition confirmation means measures, for example, the interval of generation of the output signal of the signal coil 1b. Therefore, it can be realized by means for measuring the instantaneous speed of the engine and means for outputting an ignition confirmation signal when it is detected that the instantaneous speed exceeds a set value.

In this example, the charge is stored in the charge storage element 21a by the charge storage element 21a, the transistor 21d, the resistors 21b, 21e, 21f, and the diode 21c when the ignition check means determines that the engine has been ignited. A charge storage circuit 21 for storing is configured. The resistor 22
a constitutes a discharge circuit 22 for discharging the charge of the charge storage element 21a over a sufficiently long time, and the field effect transistor 23a and the resistor 23b constitute an initial start / restart signal generation circuit 23.

In the initial start / restart signal generating circuit 23, when a predetermined amount of electric charge is accumulated in the electric charge accumulating element 21a, the field effect transistor 23a is turned on to make the potential of the input port B2 of the microcomputer almost zero. To generate a restart signal (zero level or low level signal). When the charge stored in the charge storage element 21a is less than a predetermined amount, the field effect transistor 23a is turned off and the input port B2 of the microcomputer is turned off.
The initial start signal is generated by setting the potential of the high level to a high level.

The microcomputer 4 checks the potential of the input port B2 when controlling the starting of the engine, and when the potential of the input port B2 is at a high level (when the initial starting signal is generated). ) Calculates the fuel injection time suitable for the initial start, and when the potential of the input port B2 is at zero level (or low level) (when the restart signal is generated), Calculate the appropriate fuel injection time.

In the above embodiment, the microcomputer 4 is provided separately from the microcomputer 4 by the signal generator 1, the waveform shaping circuit 6, and the injection command signal generating circuit 7 for hardware control. slow Tokiwa outputs over de control injection command signal Vhi, steady Tokiwa over de control injection command including information of the fuel injection time suitable for steady-state operation at the time of steady operation of the engine containing information suitable fuel injection time Signal Vhn
Is generated.

[0035] or a signal selection circuit 8, a switching circuit 9, by the injector drive circuit 3, the microcomputer
4 flows a drive current between the injector 2 of the fuel injection time given by the soft control injection command signal Vs when in a state of operating normally, the microcomputer 4
Is in a state where it does not operate normally, an injector drive current supply control circuit that supplies a drive current to the injector 2 during a fuel injection time given by the hard control injection command signal Vh output from the hard control injection command signal generation circuit 100 101 is configured.

The hard control injection command signal Vh and the soft control injection command signal Vs may be signals containing information on a predetermined fuel injection time, and need not necessarily be rectangular wave signals. For example, a pair of pulse signals including a pulse signal generated at the fuel injection start position and a pulse signal generated at the fuel injection end position may be used as the injection command signal. Each injection command signal can take various forms according to the configuration of the injector drive circuit 3 .

The soft control injection command signal Vs and the hard control injection command signal Vh need not have the same waveform, and may be different. For example, injection command signal for software control
Vs rises at the fuel injection position, is a rectangular wave signal having a signal width corresponding to the fuel injection time, and the hard control injection command signal Vh is a signal V obtained from the signal generator 1.
Pulse signals obtained by shaping the waveforms of p1 and Vp2 (FIG. 8A) can also be used. When a pulse signal obtained by shaping the waveform of each of the signals Vp1 and Vp2 is given to the injector drive circuit 3 so that a drive current flows through the injector 2 , the injector 2 intermittently injects fuel. There is no hindrance to the operation of the institution.

In the example shown in FIG. 1, the signal generator 1 for providing rotation angle information to the microcomputer is also used as a signal generator for obtaining the injection command signal Vh for hardware control. In addition to the signal generator 1 for providing a hard control injection command signal, the signal generator for obtaining the hard control injection command signal is provided separately, and the output signal of this signal generator is shaped into a waveform. , The hardware control injection command signal Vh ( Vhi and Vhn ) may be obtained.

For the sake of simplicity, in the present embodiment, both the soft control injection command signal Vs and the hard control injection command signal Vh are rectangular wave signals rising at the fuel injection position, and the respective signal widths are equal to the fuel width. It is assumed that it corresponds to the injection time.

The drive signal Vd includes injection command signals Vh, V
s may be any signal that instructs the injector drive circuit 3 to supply a drive current to the injector 2 during the fuel injection time given by s , and the injection command signals Vh, Vs and the drive signal Vd do not necessarily have the same waveform. good. As the drive signal Vd, a signal having an appropriate waveform according to the configuration of the injector drive circuit 3 can be used. In the present embodiment, for the sake of simplicity, the injection command signals Vh and Vs and the drive signal Vd are used. The waveforms are the same.

FIG. 3 shows an algorithm of control performed by the microcomputer 4 in the above embodiment. The operation when the control algorithm shown in FIG. 3 is followed is as follows. When the voltage of the generator 10 is established at the time of the initial startup, the operation of the microcomputer 4 is started. When the operation of the microcomputer is started, first, initial setting of each unit is performed. After the initial setting, the potential of the input port B2 is confirmed, and it is determined whether it is an initial start or a restart. As a result, when the potential of the input port B2 is zero (or low level) and it is confirmed that the initial start is performed, the data for the initial start is read from the ROM and the initial start is set. Next, it is determined whether or not to perform the start-up control. If it is confirmed that the start-up control should be performed, the potential of the input port B2 is checked again to determine whether the initial start or the restart is to be performed. Do. As a result, when it is confirmed that the initial start is performed, a fuel injection amount and an injection position suitable for the initial start are calculated using the read data, and the calculated fuel injection time and injection position are calculated. An injection command signal including information is generated.

After the initial setting, when the potential of the input port B2 is confirmed to be high and the restart is confirmed, the data for the restart is read from the ROM and re-started. Make start settings. Next, it is determined whether or not the start-time control should be performed (whether or not the engine has been started). If it is confirmed that the start-time control should be performed, the initial start or the restart is performed again. Is determined. As a result, when it is confirmed that the restart is performed, the fuel injection time and the injection position suitable for the restart are calculated using the read data, and the information of the calculated fuel injection time and the injection position is calculated. And an injection command signal including the same.

As a result of the determination as to whether or not the start-time control should be performed, when it is confirmed that the engine has already been started and the steady-state control should be performed, the fuel injection suitable for the steady operation is performed. The time and the injection position are calculated based on various control conditions, and an injection command signal including information on the calculated fuel injection time and the injection position is generated.

The determination as to whether or not to perform the starting control is made, for example, by detecting the engine speed. The rotation speed can be detected by counting the time from when the signal generator 1 generates a specific signal to when the same signal is generated next time.

Next, the operation of the embodiment shown in FIGS. 1 and 2 will be described with reference to FIGS. 4A to 4D show output voltage voltages V1 and V1 of the power supply circuit 11, respectively.
The potential V2 of the output port A3 of the microcomputer 4 ;
It shows a temporal change of the voltage V3 across the charge storage element 21a and the potential V4 of the input port B2 of the microcomputer 4 at the time of initial startup. 5 (A) to 5 (D) show temporal changes at restart of V1 to V4, respectively.

When the starting device is operated at the time of the initial startup of the engine and the engine is rotated at time t1, a voltage is induced in the power generation coil 10b, so that the output voltage V1 of the power supply circuit 11 as shown in FIG. Rises. As the voltage increases, the potentials of the output port A3 and the input port B2 of the microcomputer 4 also increase. Similarly, since a voltage is induced in the power generation coil 10c, the output of the power supply circuit 12 also increases. Since a large voltage is not required to supply a necessary drive current to the injector 2, the injector drive circuit 3 is in a state where it can operate sufficiently immediately after the start operation.

[0047] Until the output voltage V1 of the power supply circuit 11 reaches the voltage V1o required to operate the microcomputer 4, since the microcomputer 4 can not operate, switch signal Ve is not output. Therefore, at this time, the switching circuit 9 provides the injector control circuit 3 with the hard control injection command signal Vh output from the signal selection circuit 8 as the drive signal Vd. The injector drive circuit 3 supplies a drive current to the drive coil 2a of the injector 2 while the drive signal Vd is being supplied.

When the induced voltage of the power generation coil 10b is established and the predetermined power supply voltage Eo is supplied from the power supply circuit 11 to the microcomputer 4 at time t2, the microcomputer 4 outputs the switching signal Ve from the output port A2. . The switching signal Ve is supplied to the switching signal supply control circuit 13
The switching circuit 9 supplies the software control injection command signal Vs given from the microcomputer 4 to the injector drive circuit 3 as a drive signal Vd. The injector drive circuit 3 outputs the drive signal V
While d is given, a drive current is applied to the drive coil 2a of the injector to inject fuel.

If the engine has not been started when the microcomputer 4 starts operating, the starting control is performed. During initial startup, when the ignition of the engine has not yet been carried out, not causes charges to be accumulated in the charge storage element 21a, thus the electric field effect transistor 23a is in a blocked state, the input port B2 of the microcomputer 4 The potential V4 is at a high level. At this time, the microcomputer 4 generates an injection command signal for giving an appropriate fuel injection amount and injection position at the time of initial startup.

When the ignition of the engine is detected at time t3 after the microcomputer 4 starts operating, FIG.
An output port A3 of microcomputer 4 as shown in
2 is turned on, the transistor 21d of FIG. 2 is turned on, and the charge storage element 21 is supplied from the power supply circuit 11 through the transistor 21d, the diode 21c, and the resistor 21b.
The electric charge is accumulated in a. Accordingly, the voltage V3 across the charge storage element 21a increases as shown in FIG.
At time t4, this voltage V3 becomes the field effect transistor 23a.
Upon reaching the level Ef required to conduct, electric field the effect transistor 23a becomes conductive, becomes substantially zero potential V4 of the input port B2 of the microcomputer as shown in FIG. 4 (D) (restart signal Occurs). Thereafter, as long as the voltage between both ends of the charge storage element 21a is equal to or higher than the level Ef, the potential of the input port B2 is kept almost zero (the state where the restart signal is generated is kept). When the operation of stopping the engine is performed at time t5 (the ignition operation is stopped), the rotation speed of the engine decreases, so that the voltage of the power generation coil 10b decreases, and the output voltage V1 of the power supply circuit 11 decreases. I will do it. When the engine stops at time t6, the voltage V1 becomes zero, but the resistor 22a for discharging the charge storage element 21a is turned off.
Has a sufficiently large resistance value, the charge of the charge storage element 21a is slowly discharged over a sufficient time. Therefore, even after the engine stops, the field effect transistor 23a keeps the conduction state for a predetermined time, and the state where the restart signal is generated is kept.

As shown in FIG. 5A, when the engine is restarted at time t1 ', when the voltage of the generator 10 is established at time t2' and the microcomputer 4 starts operating, the input is started. Since the potential V4 of the port B2 is zero (a restart signal is generated), the microcomputer
Numeral 4 generates an injection command signal Vs for giving a suitable fuel injection time and injection position at the time of restart.

When the engine is started, the microcomputer
4 before the operation starts, the hard control injection command signal V
When the engine is started by h , the microcomputer 4 immediately shifts to the control in the steady state after the operation is started, and calculates the fuel injection time suitable for the steady operation based on various control conditions. An injection command signal Vs including information on the fuel injection time is generated.

When the microcomputer 4 does not perform a normal operation in the steady operation state of the engine, for example, when the microcomputer malfunctions and the engine goes out of control, the signal selection circuit 8 supplies the steady-state hard control injection. The command signal Vhn is selected, and the steady-state hard control injection command signal Vhn is supplied to the switching circuit 9 as the hard control injection command signal Vh. At this time, since the switching signal supply control circuit 13 inhibits the supply of the switching signal Ve to the switching circuit 9, the switching circuit 9 outputs the hard control injection command signal Vh to the drive signal Vh.
This is given to the injector drive circuit 3 as d.

A program for checking the operation of the microcomputer is incorporated in the program for operating the microcomputer 4 so that the microcomputer stops outputting the switching signal when the operation of the microcomputer becomes abnormal. In this case, the switching signal supply control circuit 13 can be omitted.

When starting the engine in a state where the microcomputer 4 has failed, first, the signal selection circuit 8
A slow Tokiwa over de to select a control injection command signal Vhi made to perform the starting of the engine, then the steady Tokiwa over de control injection command signal Vhn the signal selection circuit 8 after the engine is started
May be selected. Switching from the state in which the low-speed hard control injection command signal Vhi is selected to the state in which the steady-state hard control injection command signal Vhn is selected is performed, for example, by detecting the engine speed and setting the engine speed to the set value. It is preferable to automatically perform the operation when the number exceeds the limit.

FIG. 6 shows an example of the configuration of the switching circuit 9 in the embodiment of FIG. 1. In the switching circuit shown in FIG. 6, when the switching signal Ve is supplied, the transistor TR1
Conducts and short-circuits the hard control injection command signal Vh.
At this time, since the transistor TR2 is turned on and the transistor TR3 is kept in the cut-off state, the soft control injection command signal Vs is allowed to be input to the OR circuit OR.
Therefore, when the switching signal Ve is given, the soft control injection command signal Vs is given to the injector drive circuit 3 as the drive signal Vd through the OR circuit OR.

When the switching signal Ve is not supplied, the transistor TR2 is turned off and the transistor TR3 is turned on, so that the soft control injection command signal Vs is short-circuited, and the command signal Vs is supplied to the OR circuit OR. Is prevented. At this time, since the transistor TR1 is in the cut-off state, the injection command signal Vh for hardware control is supplied to the injector drive circuit 3 as the drive signal Vd through the OR circuit OR.

FIG. 7 shows a signal generator 1 , a waveform shaping circuit 6,
3 shows an example of the configuration of a part of a hardware control injection command signal generation circuit 7 and a signal selection circuit 8. Signal generator 1
Generates pulse signals Vp1 and Vp2 having different polarities as shown in FIG. 8A only once per rotation in synchronization with the rotation of the engine. Here, the positional relationship between the rotor 1A of the signal generator 1 and the signal emission 1B is set so that the signal Vp1 generated first reaches the threshold level at the fuel injection position of the engine.

The waveform shaping circuit 6 outputs signals Vp1 and Vp2, for example.
The flip-flop circuit is set and reset by a pulse signal Vp1 after the pulse signal Vp1 reaches a threshold level as shown in FIG.
A rectangular wave signal Vq having a signal width corresponding to the time until p2 reaches the threshold level is generated. This square wave signal is inverted by the inverter IN, and the capacitor C1 is charged through the resistor R2 by the output signal Vq '(FIG. 8C) of the inverter. When the output of the inverter IN is zero (ground level), the charge of the capacitor C1 is equal to the diode D1, the output circuit of the inverter circuit IN, and the ground circuit (FIG.
(Not shown) . The waveform of the terminal voltage Vc1 of the capacitor C1 is as shown in FIG. 8D, and this voltage Vc1 is input to the inverting input terminal of the comparator CP1.

In order to detect the ambient temperature and the temperature of each part of the engine, a temperature sensor including a positive temperature-sensitive resistance element Rth is provided. The reference voltage Vr connected between the output terminals of the power supply and obtained at both ends of the resistor R3 is compared with the comparator CP.
1 is input to the non-inverting input terminal. Comparator C
P1 is the reference voltage Vr is the terminal voltage Vc1 of the capacitor C1.
And outputs a rectangular-wave-shaped low-speed hard control injection command signal Vhi which is at a high level during a period exceeding the threshold value. The magnitude of the reference voltage Vr increases when the temperature of the engine is low and the resistance value of the temperature-sensitive resistance element Rth is low, and decreases when the temperature of the engine increases and the resistance value of the temperature-sensitive resistance element Rth increases. Become. Thus the ambient temperature and engine low speed Tokiwa over de control injection command signal Vhi when the temperature is low becomes a signal wider waveform as shown in FIG. 8 (E), at a low speed when the temperature of the engine is high hard over <br/> de control injection command signal Vhi signal width is narrower waveform than at the low temperature, as shown in FIG. 8 (F).

The output Vq of the waveform shaping circuit 6 is
The voltage is applied to both ends of a series circuit of a resistor R5 and a variable resistor VR constituting a throttle sensor through M1. The square wave signal (FIG. 8G) V obtained at the output of the amplifier AM1
a is divided by a voltage dividing circuit composed of a resistor R5 and a variable resistor VR, and a rectangular wave reference signal Vf is obtained at both ends of the variable resistor VR. When the throttle opening is large, the resistance value of the variable resistor is large, so that the peak value of the reference signal Vf is high as shown by the broken line in FIG. When the throttle opening is small, the resistance value of the variable resistor VR becomes small.
(H), as shown by the solid line. The peak value of the reference signal Vf changes almost in proportion to the throttle opening. The reference signal Vf is input to the inverting input terminal of the comparator CP2.

The output of the waveform shaping circuit 6 is also supplied to the amplifier AM
The output of the amplifier charges the capacitor C2 through the resistor R4 . As shown in FIG. 8H, the terminal voltage Vc2 of the capacitor C2 rises linearly with time. When the square wave signal Vq becomes zero, the electric charge of the capacitor C2 is discharged instantaneously through the diode D2. The terminal voltage Vc2 of the capacitor C2 is input to the non-inverting input terminal of the comparator CP2.

The comparator CP2 outputs a steady-state hard-control injection command signal Vhn in the form of a rectangular wave which becomes high during the period when the reference signal Vf exceeds the capacitor terminal voltage Vc2. When the throttle opening is small, the command signal Vhn has a waveform with a narrow signal width as shown in FIG.
When the throttle opening is large, the waveform has a wide signal width as shown in FIG.

In the example shown in FIG. 7, the inverter IN, the resistors R2 and R3, the capacitor C1, and the temperature-sensitive resistor Rth
When, by a comparator CP1, a temperature compensation circuit for changing the information of the fuel injection time providing slow Tokiwa over de control injection command signal Vhi in accordance with the temperature information such as the temperature of the ambient temperature and the engine is configured. The addition and amplifiers AM1, AM2 and resistors R4, R5 and diode D2 and the variable resistor VR and the comparator CP2, change the signal width of the constant <br/> normal Tokiwa over de control injection command signal in response to the throttle opening A signal width correction circuit is configured to be used.

[0065] As in the example shown in FIG. 7, when the information of the fuel injection time providing slow Tokiwa over de control injection command signal Vhi is changed according to the temperature information, the temperature of the ambient temperature and the engine is low In addition, the injection time can be lengthened to make it easier to start the engine. The Varying according to the signal width of the steady Tokiwa over de control injection command signal to the throttle opening to operate stably engine is set to a length that matches the fuel injection time to the throttle opening at the time of hardware control In addition, the output of the engine can be sufficiently obtained.

In the above example, the signal width of the steady-state hard control injection command signal Vhn is changed according to the throttle opening. However, the steady-state hard control injection command signal Vhn is changed according to other control conditions. It is also possible to change the signal width of Vhn .

[0067] signal selection circuit 8 shown in FIG. 7 consists selector switch, the hardware control to select one of the low-speed Tokiwa over de control injection command signal Vhi or constant Tokiwa over de control injection command signal Vhn Switching circuit 9 as the injection command signal Vh
Give to. The changeover switch that constitutes the signal selection circuit 8 may be a manual switch, or may be an electrically controlled switch such as a relay or a semiconductor switch.

[0068] In the embodiment shown in FIG. 7, but by changing the low speed Tokiwa over de control injection command signal Vhi and constant Tokiwa over de signal width of the control injection command signal Vhn in one circuit, the signal A plurality of rectangular wave generating circuits for generating rectangular wave signals having different signal widths in synchronization with the pulse signal Vp1 obtained from the generator 1 are provided, and are provided in accordance with control conditions such as engine temperature and throttle opening. Alternatively, the outputs of the plurality of rectangular wave generating circuits may be selected and output.

In the above embodiment, the microcomputer
4 , the switching signal Ve is generated. However, a voltage detection circuit for detecting the power supply voltage of the microcomputer 4 is provided, and the voltage detected by the voltage detection circuit is necessary for the microcomputer 4 to operate normally. The switching signal Ve may be generated by a hardware circuit when there is a minimum value or more.

[0070] Also by a method such as monitoring the speed change of the engine, by providing a circuit for determining whether operation of the microcomputer is normal or abnormal, this discrimination circuit, the operation of the microcomputer 4 is abnormal In such a case, the switching signal Ve may be generated .

[0071] In the embodiment example above, the micro computer
Although the fuel injection position and the fuel injection time are calculated by the microcomputer 4 , the microcomputer 4 calculates only the fuel injection time and the fuel injection position can be determined by the timing signal obtained from the signal generator 1. .

In the above embodiment, the microcomputer
Injection command signal Vh for hardware control obtained by the signal generator 1 and the electronic circuit 7 when the microcomputer 4 is not operating normally.
Is used to drive the injector 2 , but in the present invention, as described above, the hard control injection command signal
The present invention is not limited to the case where Vh is used, and can be widely applied to a fuel injection device that controls an injector using a microcomputer driven by the output of a generator 10 driven by an internal combustion engine.

[0073]

As described above, according to the present invention, the microcomputer is provided with an initial start / restart signal generating circuit for generating an initial start signal at the time of initial start and generating a restart signal at the time of restart. When the initial start signal is generated at the time of starting, the appropriate amount of fuel is injected at the time of the initial start, and when the restart signal is generated, the appropriate amount of fuel is injected at the restart. Because
There is an advantage that the engine can be smoothly restarted by preventing the amount of fuel supplied to the engine at the time of restart from becoming excessive.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration example of an initial start / restart detection circuit used in the embodiment of FIG. 1;

FIG. 3 is a flowchart showing a control algorithm according to the embodiment of the present invention.

FIG. 4 is a diagram showing a temporal change of a voltage of each part in FIG. 2 at the time of initial startup.

FIG. 5 is a diagram showing a temporal change in voltage of each unit in FIG. 2 at the time of restart.

FIG. 6 is a connection diagram showing a specific example of a switching circuit used in an embodiment of the present invention.

FIG. 7 is a connection diagram showing a specific configuration example of a main part of the device of the present invention.

8 (A) to 8 (J) are waveform diagrams showing signal waveforms at various parts in FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Signal generator 2 Injector 3 Injector drive circuit 4 Microcomputer 6 Waveform shaping circuit 7 Injection command signal generation circuit for hardware control 8 Signal selection circuit 9 Switching circuit 10 Generator 11 and 12 Power supply circuit 13 Switching signal supply control circuit 100 Hard injection Command signal generation circuit 101 Injector drive current supply control circuit 20 Initial start / restart detection circuit 21 Charge storage circuit 22 Discharge circuit 23 Initial start / restart signal generation circuit

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-3-172555 (JP, A) JP-A-61-271881 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) F02D 41/00-45/00 395

Claims (1)

(57) [Claims] An injector for injecting fuel when a drive current is applied, a fuel injection time suitable for starting the internal combustion engine when the engine is started, and a fuel injection time suitable for a steady operation after the start of the engine. Microcomputer based on various control conditions to generate an injection command signal including information on the calculated fuel injection time, and a drive current to the injector during the fuel injection time given by the injection command signal. And a fuel injection device for an internal combustion engine that operates using a generator driven by the internal combustion engine as a power supply, wherein the microcomputer checks ignition of the engine when the internal combustion engine is started. Ignition confirmation means, and a charge storage circuit for storing charge in the charge storage element when the ignition of the engine is confirmed by the ignition confirmation means A discharge circuit for discharging the charge stored in the charge storage element with a sufficiently large time constant, and generating an initial start signal when a predetermined amount of charge is not stored in the charge storage element, An initial start restart signal generating circuit for generating a restart signal when a predetermined amount of electric charge is stored, wherein the microcomputer performs an initial start when the initial start signal is generated when the internal combustion engine is started. A fuel injection device for an internal combustion engine, which calculates a fuel injection time that is suitable at the time of restart and calculates a fuel injection time that is suitable at the time of restart when a restart signal is generated.