JPS62233475A - Control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent undue power consumption, by determining whether or not a control device for an engine can normally operate from a power voltage in the control device, and making the operation of a starter invalid when the power voltage is in such a condition where a normal control operation of the control device cannot be provided. CONSTITUTION:The operational condition of a control device 5 is determined by a voltage signal 14, and the start of an engine is detected by a voltage signal 15. When it is detected that a power voltage of a microcomputer incorporated in the control device 5 is in such a condition where the control device 5 cannot normally operate at the starting of the engine, a low-voltage detector 13 is operated. As a result, a coil 12a in a magnet SW 12 is excited to open a contact 12b and thereby open a circuit of a coil 11a in a magnet SW 11. As a result, even when a key SW 2 is in the position of a fixed terminal C at the starting of the engine, a contact of the magnet SW 11 is not closed, and therefore no power is supplied to a starter 3 to inhibit the operation of the starter 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention provides a control device f! for an internal combustion engine that stops or prevents an invalid starting operation of the internal combustion engine. It is related to.

[Conventional technology]

Recently, electronic control has been very actively introduced into internal combustion engines of automobiles, and one example is fuel injection devices.

Many fuel injection devices use a microcomputer, and the system is configured around this. Therefore, when the micro pump is stopped, fuel is no longer supplied to the engine, making it impossible to stop or start the engine.

FIG. 4 is a circuit diagram showing the control equipment of a conventional internal combustion engine. In this FIG. 4, 1 is a battery that supplies power;
Reference numeral 2 denotes a key switch (hereinafter referred to as key SW) provided on the output side of the battery 1 and for turning on and off the power supply.

This key SW2 has fixed terminals A, B, and C and a movable terminal 2A, and the movable terminal 20 is connected to the positive electrode of the battery 1. The fixed terminal A is not connected, and the fixed terminal B is directly connected and connected to the control bag [5] via the primary coil of the injector 7 and the ignition filter 8.

In addition, the fixed terminal C of the key SW2 is connected to the magnetic switch 4.
(hereinafter referred to as magnet SW) is grounded via a coil 4a.

This magnet SW4 has a contact 4b, and the contact 4b and the starter 3 are connected in series between the positive electrode of the battery 1 and the ground. The starter 3 receives power from the battery 1 when starting an engine (not shown) and operates to start the engine.

Reference numeral 6 indicates input signals, one of which includes an input signal from the fixed terminal C of the key SW2, and other input signals from various sensors (not shown) installed in the engine.

This input signal 6 is sent to the control device 5, and the control device 5 calculates and determines the operating state from this input signal 6, and drives the injector 7 to inject fuel under appropriate operating conditions. .

Here, the control device 5 is constructed using a microcomputer, and the input signal 6 includes an angle signal generated at a predetermined crank angle of the engine necessary for ignition timing control, and the ignition filter 8 is It also includes a driving ignition function.

Next, the operation will be explained. When the engine is stopped, press key S.
W2 is at the position of fixed terminal A, and the output of battery 1 is cut off.

When starting the engine, the key SW2 is first set to the fixed terminal B position, and power is supplied to the power terminal of the control device 15.

Next, set the key SW2 to the fixed terminal C position, and in addition to the power supply state from the fixed terminal B to the control bag f5, the fixed terminal C
Power is supplied to the coil 4a of the magnet SW4 to operate it, its contact 4b is closed, and power is supplied to the starter 3 from the battery l.

In this way, electric power is supplied to the starter 3, the starter 3 rotates, and the engine starts.

1vlJall equipment af5a-+-8W2 (Dm fixed m child C
(Because it has D711 pressure as one of the input signals 6,
In addition, since the period of the angle signal provided as one of the input signals 6 for ignition is long, it is determined that the engine is in a starting state, and the injector 7 and ignition coil 8 are driven, fuel is supplied, and the ignition voltage is set. generate and start the engine.

When the engine starts, the key SW2 is returned from the fixed terminal C position to the fixed terminal B position. In this case, power is supplied via the key SW2 only from the position of the fixed terminal B to the control bag fi't5, and is not supplied from the position of the fixed terminal C to the magnet SW4, so that the operation of the starter 3 is stopped.

The control device 5 determines the operating state of the engine from the input signals 6 from various sensors, and injects the appropriate amount of fuel.
) The engine is operated by driving the Ector 7 and driving the ignition filter 8 to generate the ignition voltage at a proper rank angle position.

[The problem to be solved by the invention] In the conventional internal combustion engine device described above, when the charging rate of the battery 1 is low (when the charge is insufficient) or when the engine is cold, the engine When the key SW2 is set to the position of the fixed terminal C and the stars 3 are activated in order to start the engine, the output voltage of the battery 1 becomes very low, for example, sometimes less than 5V.

In such a case, the control device i5 may be unable to operate normally due to the low power supply voltage, and may activate the reset function and stop the control operation (stop the fuel injection and ignition operations).

Generally, the power supply voltage of a microcomputer is 4.5 to 5
．． It is defined in 5 cults. The power supply voltage input to the control device 5 is input to the microcomputer via its power supply circuit, so the power supply voltage is lower than the output voltage of the battery 1 by the loss in the IL source circuit (actually, there is also loss in the vehicle wiring). The voltage is input to the microcomputer.

Therefore, in order for the microcomputer of the control device 5 to always perform normal control, a voltage equal to 4.5 corts plus the loss voltage of the power supply circuit of the control device 5 must be input as the power supply voltage of the control device 5. is necessary.

On the other hand, regarding the operation of the starter 3, whether it rotates or not and its rotation speed are determined by the relationship between the input power and the load, so the low output voltage of the battery 1 may immediately become a problem. do not have.

In combinations of currently produced engines and starters 3, even if the power supply voltage is around 5 volts, the engine may operate at a rotational speed that is not much different from 8 to 10 volts.

Furthermore, when starting the engine, unless the starter 3 rotates at a particularly low speed, it is usually determined that the engine and the parts shown in FIG. 4 are normal.

Generally, the output voltage of the battery 1 at the time of starting is measured with a voltmeter, and the judgment is made intuitively based only on the starter 30 rotation condition, without making a judgment together with the starter 30 rotation condition.

This is an engine that does not have conventional electronic control, or does not have electronic control for the basic control parts directly related to startability such as the fuel system and ignition system, and starts when the starter 3 rotates. This is because the judgment is made intuitively based on the experience of thinking that the engine will start when the starter 3 rotates.

FIG. 5 shows an example of the output voltage of the battery 1 when starting the engine. Here, it is shown that 5 melts are required for the control device 5 to perform the control operation normally, and when this patch IJ llll pressure becomes 5 melts or less, the control unit [5 goes into the reset state and normal control is performed. Unable to perform movements.

The battery voltage decreases in this way when the engine is in a compression process where its rotational resistance increases. However, the starter 3 is in the same rotational state as when the power supply voltage is 8 to 10 g. For example, this can be confirmed on an actual machine at temperatures of around 20°C or higher.

In this way, even if the starter 3 operates normally,
The control device 5 enters a reset state when the power supply voltage 5 is lower than rut and does not perform any control operation, so fuel is not supplied and the engine does not start.

From the above, the control device 5, which has a microcomputer, cannot perform normal control (fuel injection and ignition operations) when the power supply voltage drops below 5°C, and the starter 3 installed in the engine has a power supply voltage of 5°C or lower. 8-1 before and after root
In the conventional device described above, the control device 5 operates at a rotation speed that is not much different from that at 0&rut, and it is generally considered that the engine and its control device are normal if the starter 3 rotates. Even at low voltages where normal control operations cannot be performed, the starter 3 rotates as usual, so the starter 3 is activated by continuous or repeated starting operations until the engine starts, and the starter 3 does not operate at all. There is a problem in that the power of the battery 1 is consumed until it runs out of power, causing the battery 1 to become fatigued.

This invention was made to solve this problem, and when the power supply voltage of the control device (output voltage of the engine) becomes low voltage when starting the engine, the starter stops operation or an alarm is issued. The object of the present invention is to obtain a control device for an internal combustion engine that provides notification.

[Failure to solve the problem]

The control device for an internal combustion engine according to the present invention provides a control device for an internal combustion engine.
I + If adjustment θ) 4'' 1 Calcium soil ξ y)ri fin 'A hundred snow mouth;
- The starter operates every 1118 times, and is provided with means for stopping the starter's operation or issuing an alarm.

[For production]

In this invention, if the power supply voltage of the control device is low at the time of starting the engine, the operation of the starter is stopped and an alarm is issued to notify of the abnormality.

〔Example〕

Embodiments of a control device for an internal combustion engine according to the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing the configuration of one embodiment. In FIG. 1, parts that are the same as those in FIG. 4 are given the same reference numerals, and a description of the structure thereof will be omitted, and the parts that are different from FIG. 4 will be mainly described.

In this FIG. 1, the parts indicated by 1 to 3 and 5 to 8 are the same as in FIG. 4, and the parts described below are different from those in FIG. .

That is, the contact 11b of the magnet 5W11 is provided between the positive electrode of the battery 1 and the starter 3 in the same way as in FIG. There is.

Magnet SWI 2 has coil 12 a to MIA 1
2b, and the coil 12a controls opening and closing of the contact 12b. This contact 12b is a magnet 5W11
Also, the coil/L/12a of the magnet 5W12 is connected between the coil 11& and the ground of the key S.
It is connected between the fixed terminal B of W2 and the low voltage detector 13.

This voltage detector 13 receives its power from the fixed terminal B of the key SW2, and receives a voltage signal 14 indicating the power supply voltage of the microcomputer of the control device 5 and a voltage signal 15 from the fixed terminal C of the key SW2 (when starting the battery 1 The input voltage is the output voltage, and the energization of the coil 121L of the magnet SV40 is controlled.

Here, the contact 11b of the magnet SWII is open when it is not activated and closed when it is activated, and the contact 12b of the magnet SWII 2 is closed when it is not activated and opened when it is activated. Other parts are the same as in FIG.

Next, the operation will be explained. Contact point 11b of magnet 5W11
is connected between the output of /J-terry 1 and starter 3 as in the conventional device, and when this is closed, starter 3Kt
Power is supplied and the starter 3 operates and rotates.

The fill 111L of the magnet 5W11 is connected between the fixed terminal C of the key SW2 and one end of the contact 12b of the magnet SV40. Magnet) SV40 contact 12b
The other end of the coil is grounded, and these coils 11 j
Since these contacts are closed when L t 12 m is not energized and inactive, the side of the coil lla of the magnet SWI 1 connected to the contact 12b of the magnet 5W12 is grounded.

In other words, when the key SW2 is set to the fixed terminal C position when the magnet 5W12 is not activated, the coil 1laK of the magnet SWI 1 is energized, its contact 11b is closed, and the starter 3 receives power from the battery 1. is supplied, and the starter 1 operates.

However, when the magnet SWI 2 is activated (when its coil is energized), its contact 12b is open, so the coil 11a of the magnet SWI 1 is not energized and the starter 3 is not activated.

The low voltage detector 130 inputs are two types of voltage signals 14.15. The voltage signal 14 indicates the power supply voltage applied to the microcomputer built into the control device 5. From this voltage signal 14, the power supply voltage applied to the microcomputer is known and whether the control device 5 is in a state where it can perform normal control operations. I'm trying to decide what to do.

The voltage signal 15 is the voltage of the fixed terminal C of the key SW2,
Since the output voltage of the battery 1 is reached only when the key SW2 is set to the fixed terminal C position, it is possible to know that it is time to start the engine by activating the starter 3.

That is, the operating state of the control device 5 is determined from the voltage signal 14, and the time of engine startup is detected from the voltage signal 15, and the control bag @5 cannot perform normal control operations when the engine is started. When it is detected that the power supply voltage of the microcomputer is present in the state, the low voltage detector 13
works.

When the low voltage detector 13 is activated, the coil 12& of the magnet 5W12 is energized, the contact 12b of the magnet SV40 is opened, the circuit of the fill 11& of the magnet 5W11 is opened, and the key SW2 is set to the fixed terminal C position. Even when the engine is started, the contacts of magnet SWI 1 do not close, so power is not supplied to starter 3.
Starter 3 does not operate.

FIG. 2 shows a concrete example of the low voltage detector 13. Here, 21 is a voltage comparator. This voltage comparator 210
The voltage signal 14 divided by the resistors 22 and 23 is input to the inverting input terminal ((-) input terminal).

Further, a reference voltage diode 25 and a resistor 24 are connected between the power supply and the ground, and the non-inverting input terminal ((+) input terminal) of the voltage comparator 21 is connected to the connection point of the reference voltage diode 25 and the resistor 24. is applied to the first input terminal of the AND circuit 26, and the voltage signal 15 divided by the resistors 27 and 28 is input to the other terminal of the AND circuit 26.

The output of the AND circuit 26 is stored in a memory 29. The output of the memory 29 is stored in a transistor 30 (hereinafter referred to as T
It is designed to be added to the pace of (r).

The emitter of the Tr 30 is grounded, and the collector is connected to the coil 12a of the magnet SW 12 shown in FIG.

Next, the operation of the second IA will be explained. The voltage signal 14 is input to the inverting input terminal of the voltage comparator 21 after being divided by resistors 22 and 23, and the other non-inverting input terminal is input to the resistor 24.
A reference voltage generated by a reference voltage diode 25 based on a bias current determined by the reference voltage diode 25 is input.

The reference voltage by this reference voltage diode 25 is 4.5d
I keep it below ζ. The reason for this is that the normal control operation of the microcomputer may become impossible, and even if the power supply voltage drops to 4.5 melt or less, the reference voltage remains stable, and the power supply voltage of the microcomputer This is to reliably detect that the voltage has become 4.5 volts or less.

Therefore, for example, if the reference voltage of the reference voltage diode 25 is 3 gerts, when the power supply voltage of the microcomputer becomes 4.5 kels NC (that is, when the voltage signal 14 becomes 4.5 kels), The voltage is divided by resistors 22 and 23 into three voltages and is input to the inverting input of the voltage comparator 21.

Therefore, the reference voltage by the reference voltage diode 25 is constant at 3 volts if the voltage applied to the resistor 24 is 3 volts or more, and the non-inverting input of the voltage comparator 21 is proportional to the voltage of the voltage signal I4. increases or decreases, so the voltage comparator 21
, the voltage of the voltage signal 14 (power supply voltage of the microcomputer of the control device 5) is 4.5? Output is generated when the default is below.

The output of this voltage comparator 21 is one input of an AND circuit 26. The other input of the AND circuit 26 receives the voltage signal 1.
5 is divided by a resistor 27.28 and inputted.

Both inputs of the AND circuit 26 become rHJ because the voltage signal 15 becomes rHJ and the voltage comparator 21
When the output of the AND circuit 26 becomes rHJ, that is, when the engine is in the starting state and the power supply voltage of the microcomputer of the control device Rs becomes 4.5 sals or less, the output of the AND circuit 26 becomes rHJ. Become.

Once the output of the AND circuit 26 reaches rHJ, the memory 29 stores it and generates an output in response to this.

Since the Tr 30 is driven by the output of the memory 29, when the memory 29 generates an output, the Tr 30 is activated and turns on.

In this way, when the Tr 30 is turned on, the coil 12aKa of the magnet SWI 2 is electrically charged, and its contact 1
2b is opened and the engine is started, in which the key SWI 2 is set to the position of the fixed terminal C as described above, the magnet SWI 1 does not operate, so the starter 3 does not operate.

In this embodiment, the power supply of the low voltage detector 13 is turned on using the key SW2.
Since the detection result is stored in memo number 29, once the power supply voltage of the microcomputer becomes 4.5 cels or less, the key SW2
Unless it is returned to the fixed terminal A, the storage in the memory 29 can prevent unnecessary operation of the starter 3 thereafter.

Furthermore, since the AND circuit 26 performs a logical product with the voltage signal 15, it is possible to limit the voltage drop at the time of starting the engine, and it is possible to detect a more specific phenomenon, but this is not always necessary. The AND circuit 26 may be omitted.

If the AND circuit 26 is omitted, a drop in the tS voltage of the microcomputer can be detected at all times, not only when the engine is started, which may be sufficient for some applications (for example, when monitoring a single Km source voltage).

Further, the voltage signal 14 is the power supply voltage of the microcomputer itself, but since the control device 5 usually has a plurality of circuit voltages, the microcomputer's 'rr1#
There are other circuit voltages that behave in the same way as the voltage, and the power supply voltage of the microcomputer may be determined from these.

Depending on the configuration of the power supply circuit, the higher the power supply voltage, the smaller the delay with respect to the movement* of the output voltage of the output terminal 1, so that it is possible to detect an abnormality more quickly.

In addition, in order to assist the control function in the event that the power supply voltage of the micro pump computer drops and normal control operation becomes impossible as described above, the control device is equipped with an auxiliary circuit that controls the engine at low voltage. It is also effective for monitoring the power supply voltage of a microcomputer.

FIG. 3 shows another embodiment of the invention. This is designed to issue an alarm to notify the user when the power supply voltage of the microcomputer is reduced 17 and becomes abnormal.

In FIG. 3, reference numeral 41 is a light emitting device consisting of a light emitting diode 42 and a resistor 43 for controlling the flow to the light emitting diode 42.

The low voltage detector 13 is activated when the power supply voltage of the microcomputer inside the control device 5 decreases, and causes a current controlled by a resistor 43 to flow through the light emitting diode 42, causing it to emit light.

In this way, an abnormality can be displayed and an alarm can be issued. In FIG. 3, a sound generator may be connected in place of the light emitter 410 to issue an alarm using sound waves.

〔Effect of the invention〕

As explained above, this invention uses the power supply voltage of a control device that controls engine operation to determine whether or not this control device can perform normal control operations, and to detect that the power supply voltage is such that normal control is impossible. When detected, the starter, which operates when starting the engine, is disabled or an alarm is issued, thereby preventing or reducing wasteful power consumption and fatigue of the battery, which is the engine's power source. This provides an excellent practical effect.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of the internal combustion engine control device of the present invention, FIG. 2 is a circuit diagram showing a detailed embodiment of the low voltage detector in the internal combustion engine control device of FIG. 1, and FIG. FIG. 4 is a circuit diagram of another embodiment of the control device for an internal combustion engine according to the present invention.
The figure is a circuit diagram of a conventional internal combustion engine control device.
FIG. 3 is a diagram showing characteristics of the output voltage of a battery in the control device for the internal combustion engine shown in the figure. 1... Battery, 2... Key switch, 3... Starter, 4, 11.12... Magnet switch, 5
...Control device, 7.. Injector, 8.. Ignition coil, 13..Low voltage detector, 14.15.. Voltage signal, 21.. Voltage comparator, 22-24.27 .2
8,32゜43...Resistor, 25...Reference voltage diode, 26...AND circuit, 29...Memory, 30
...Transostor, 31...Light-emitting diode, 41
...Light emitter, 42...Light emitting diode. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (3)

[Claims] (1) A battery that supplies electric power A starter that operates when starting the engine using this battery as a power source, a first control means that controls the operation of the engine, and a voltage of this first control device that reaches a predetermined voltage. A control device for an internal combustion engine, comprising a second control means that is activated when: (2) The second control means operates to disable the operation of the starter.
A control device for an internal combustion engine as described in . (3) The control device for an internal combustion engine according to claim 1, wherein the second control means operates to issue an alarm.