JP2530997Y2 - Fuel pump 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 pump for supplying fuel to an injector of a fuel injection device for an internal combustion engine.

[0002]

2. Description of the Related Art A fuel injection device for supplying fuel to an internal combustion engine includes an injector having a valve operated by an electromagnet or the like, a fuel pump for supplying fuel to the injector, and a pressure of fuel supplied to the injector. And a pressure regulator for controlling the fuel pressure to be constant. When a fuel injection command is given, a valve of an injector is opened to inject fuel.

In order to operate this fuel injection device,
During the operation of the engine, it is necessary to drive the fuel pump to supply fuel to the injector, and to start the engine without any trouble, discharge a sufficient amount of fuel from the fuel pump even at the time of starting the engine. There is a need. The fuel pump is usually composed of a pump driven by a DC motor, and is driven by a battery provided in the engine.

A battery provided in an internal combustion engine is charged by the rectified output of a magnet type alternator mounted on the engine, and the output voltage of the magnet type alternator increases as the engine speed increases. To increase the voltage, a regulator (voltage regulator) is required to prevent the voltage applied to the battery from becoming excessive.

FIG. 7 shows a configuration of a circuit for driving a load by a magnet type alternator. In FIG. 7, reference numeral 1 denotes a generating coil provided on the stator side of the magnet type alternator attached to the engine. , 2 a rectifier for rectifying the single-phase AC output obtained from the power generation coil 1, 3 inputs the output voltage of the rectifier 2
A limited DC voltage below the set value between the output terminals as
Output regulator. Output terminal of regulator 3
The DC voltage obtained between the slaves is applied to a battery 4, a fuel pump (DC motor) 5, and other loads 6.

The rectifier circuit 2 is, for example, a diode bridge single-phase full-wave rectifier circuit, and outputs a pulsating voltage rising from a zero point every half cycle of the generator output. The regulator 3 has a peak value of the output voltage of the rectifier circuit 2 at a predetermined set voltage (for example, 14 V when the battery is 12 V).
Is exceeded, the output of the generator is short-circuited by a switch such as a thyristor to prevent an excessive voltage from being applied to a battery or other load. FIG. 10 shows the operation waveforms of such a short-circuit type regulator 3, and shows a sinusoidal pulsating voltage V1 obtained from the rectifier circuit 2.
When the voltage reaches the set voltage Vr, the switch in the regulator 3 short-circuits the power generation coil 1, so that the output voltage of the regulator 3 has a waveform falling to zero after reaching the set voltage Vr.

Accordingly, the waveform of the output voltage of the regulator 3 becomes a pulse-like waveform as shown by a curve a in FIG. When this voltage is applied to the battery 4, the voltage waveform across the battery becomes a smoothed waveform as shown by the curve b in FIG. In the circuit of FIG. 7, the waveform of the voltage input to the fuel pump 5 is a waveform like this curve b, and becomes a waveform oscillating in a substantially sinusoidal manner near the set voltage Vr of the regulator.

On the other hand, the output of the DC motor, which is the driving source of the fuel pump, is substantially proportional to the magnitude of the effective voltage input to the motor (the average value of the input voltage), and the discharge amount of the fuel pump 5 is reduced to the effective voltage. It changes almost in proportion. FIG. 9 shows this state. In FIG. 9, a to c denote the average values of the input voltages of the pumps at 50% and 100% of the rated voltage, respectively.
And 200%, the relationship between the pump current (armature current of the electric motor) I and the torque τ applied to the pump is shown.
2 shows the relationship between the rotation speed N of the pump and the torque τ at%, 100%, and 200%.

FIG. 9 shows that when the same torque is applied to the pump, the lower the input voltage, the lower the rotational speed of the pump. This means that when trying to ensure the same fuel pressure, the lower the input voltage, the lower the fuel flow rate. In addition, when the number of rotations of the pump is the same, it can be seen that the lower the input voltage, the lower the pump current. This means that, when trying to make the flow rate of the fuel equal, the lower the input voltage, the lower the fuel pressure.

[0010]

[Problems to be solved by the invention] As shown in FIG.
When supplying the single-phase AC output of the magnet type AC generator to the fuel pump via the rectifier circuit and the regulator, there is no problem if the battery can be used normally, but the battery cannot be used for any reason. When it becomes possible, for example, when the battery is removed due to theft, or when the battery runs out, the output voltage of the regulator 3 as shown by the curve a in FIG. As a result, the average value of the voltage input to the fuel pump becomes extremely low, so that the pump cannot be driven sufficiently, and the fuel pressure applied to the injector is insufficient, and the fuel injection amount is insufficient. was there.

In particular, when the engine is started, the rotation speed of the generator cannot be increased, so that when the battery cannot be used, the average value of the voltage applied to the fuel pump becomes very low. Therefore, it is not possible to supply the fuel necessary for starting the engine, and it is not possible to start the engine.

In the case of an outboard motor, if such a situation occurs, it is impossible to return to the port, which is very dangerous.
In addition, since the operation of the engine cannot be continued in other vehicles and the like, much trouble is required for repairing the engine.

If the regulator is provided with a smoothing capacitor, the above problem does not occur. However, in an engine equipped with a battery, the output voltage of the regulator is generally smoothed by the battery. Even if a capacitor is provided, it only raises costs and has no real benefit. Therefore, in general, a regulator designed for use with a magnet generator for an internal combustion engine is not provided with a smoothing capacitor, and the above-described problem occurs when a fuel pump is driven by the output of the regulator. Inevitable.

An object of the present invention is to provide a fuel pump for an internal combustion engine that can operate satisfactorily even when a battery cannot be used.

[0015]

SUMMARY OF THE INVENTION The present invention provides a magnet type AC generator.
Rectifier circuit for rectifying the output of an electric machine and the generator and the rectifier circuit
DC voltage limited to the set value or less with the output of
And a regulator for outputting the output of the regulator.
The regulation of the DC power supply where the battery is connected between the terminals
DC driven by the DC voltage obtained between the output terminals of the
Using an electric motor as a drive source, the injector of a fuel injection device
It relates to a fuel pump for an internal combustion engine that supplies fuel.
You.

In the present invention , the power supply terminal of the DC motor is provided.
Connect a capacitor in parallel between
Connect the cathode of the diode to one end of the positive polarity side of the
Regulate the anode of the diode and the other end of the capacitor.
Input terminal of the DC voltage obtained between the output terminals of the
Was.

[0017]

If a capacitor is connected between the power supply terminals of the fuel pump as described above, a sufficient voltage can be supplied from the regulator to the motor of the fuel pump even when the battery cannot be used. It is assumed that no battery is connected between the output terminals of the regulator. In this case, when a capacitor is connected in parallel between the power supply terminals of the fuel pump, the load on the generator becomes larger than when the capacitor is not connected (the load current flowing when the voltage rises becomes larger). Therefore, the rise of the output voltage of the generator is delayed as compared with the case where the capacitor is not connected. Therefore, the waveform of the output voltage obtained from the rectifier circuit 2 when the battery is removed is as shown by a curve V1 'in FIG. 3, and the output voltage of the regulator is as shown by a curve a'. When the voltage V1 'reaches the set voltage Vr and the regulator operates, the output voltage of the regulator gradually decreases as the charge of the capacitor is discharged through the internal impedance of the pump. Therefore, the average value of the input voltage of the fuel pump is considerably higher than the average value of the input voltage when no capacitor is connected, and the average value of the input voltage is sufficient to operate the fuel pump satisfactorily even at a relatively low rotation speed. Become.

As described above, if the capacitor is connected in parallel between the power supply terminals of the DC motor of the fuel pump, the average value of the voltage applied to the motor can be increased even when the battery cannot be used. The engine can be operated even when the battery goes up or when the battery is removed for some reason.

If a capacitor is connected to the fuel pump as described above, when the battery cannot be used, the fuel pump can operate normally regardless of the configuration of the regulator. it can.

Further, since the output voltage waveform of the regulator contains many harmonic components, if this voltage is directly input to the DC motor, the brush and the commutator of the motor are easily damaged, and the voltage of the motor is reduced. Although the life is shortened, if a capacitor is connected as described above, the harmonic component can be absorbed by the capacitor, so that the life of the motor can be prolonged.

As described above, the positive side of the capacitor
Connect the diode cathode to one end of the
Of the regulator and the other end of the capacitor
Input terminal of the DC voltage obtained between
Density charge discharges through loads other than the fuel pump
All the charge on the condenser passes through the fuel pump.
The average value of the voltage applied to the fuel pump
Can be further increased.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG .
When the capacitor 7 is connected in parallel between the power terminals of the motive,
As shown below, the battery 4 cannot be used.
The generator coil 1 of the magnet type alternator
DC motor through the rectifier circuit 2 and the regulator 3
5 can be supplied with a sufficient voltage.

In the example of FIG. 1, the magnet type alternator is
A generator coil 1 and a rectifier circuit 2 for rectifying the output of the generator
And the output of the rectifier circuit 2 is limited to a set value or less as an input.
DC voltage by the regulator 3 that outputs the DC voltage
And a battery between the output terminals of the regulator 3.
4 are connected.

In the example shown in FIG . 1, the rectifier circuit 2 is a diode-bridge single-phase full-wave rectifier circuit, and the regulator 3 is a short-circuit type that short-circuits the power generation coil 1 when the output voltage reaches a set value. is there. An example of the configuration of the rectifier circuit 2 and the regulator 3 is shown in FIG. The regulator 3 shown in FIG. 5 includes thyristors S1 and S2 connected between one end of the generating coil 1 and ground and between the other end and ground.
And a Zener diode Z1 having a cathode connected to the positive DC output terminal of the rectifier circuit 2, and a resistor R1 connected between the anode of the Zener diode Z1 and the gates of the thyristors S1 and S2.

In the circuit shown in FIG . 5 , when the output voltage of the rectifier circuit 2 reaches a set value, the Zener diode Z1 conducts, and a firing signal is given to the thyristors S1 and S2. The output of the positive and negative half cycles of The magnet-type alternator has characteristics as shown in FIG. The curves a, b and c in FIG. 2 indicate the rotation speeds N1, N2 and N3 (N1 <N2 <N
3) shows the relationship between the output voltage and the load current of the magnet-type alternator in the case of 3), and the straight line L1 in FIG.
3 shows a load straight line when the capacitor 7 is not connected. A straight line Lc indicates a load straight line when the capacitor 7 is connected. As can be seen from FIG. 2, by connecting the capacitor 7, the load seen from the generator increases, and the load current flowing at each rotation speed increases. When the load current increases, the rise of the output voltage is delayed, so that the time required for the output voltage to reach the set voltage of the regulator becomes longer.

Now, when the condenser 7 is not connected to the fuel pump 5, it is assumed that the generator generates an output voltage like V1 in FIG. 3 at a certain rotation speed. When the condenser 7 is connected to the fuel pump, the output voltage of the generator at the same rotation speed becomes V1 'in FIG. 3 due to an increase in the armature reaction, and its rise is delayed. Regulator setting voltage
Is Vr, and the output voltage of the generator exceeds the set voltage Vr
Assuming that the power generating coil 1 is short-circuited, when the generator is outputting the voltage V1 in FIG. 3, the waveform of the output voltage of the regulator 3 is as shown by a curve a in FIG.
When the generator generates the output voltage V1 '(the capacitor 7 is connected), the waveform of the output voltage of the regulator becomes a curve a' in FIG. 3, and the average value increases. After the regulator short-circuits the generator coil, the electric charge accumulated in the capacitor 7 is discharged through the DC motor 5 (shaded portion in FIG. 3), so that the average value of the voltage applied to the motor 5 is further increased.

As described above, the direct current for driving the fuel pump
If a capacitor is connected between the power terminals of the motor 5 ,
Since the load seen from the generator becomes large and the rise of the output voltage of the generator is delayed, the waveform of the output voltage of the regulator becomes as shown by a curve c in FIG. 8, and the average value increases.
When the battery is removed, a voltage having a waveform like the curve c in FIG. 8 is applied to the fuel pump, so that the average value of the input voltage of the fuel pump can be sufficiently increased, and the fuel pump can be operated without any trouble. Can work.

However, as shown in FIG.
5 simply connect the capacitor 7 between the power terminals.
The charge of the capacitor 7 is a load other than the fuel pump (battery 4
And discharge through the load 6).
All of the stored energy is supplied to the motor 5 of the fuel pump.
Cannot be supplied, and the electric charge stored in the capacitor 7 is
Not fully available with fuel pumps.

Therefore, in the present invention, FIG.
Thus, the diode 8 is connected to one end of the capacitor 7 on the positive polarity side.
And the anode of this diode 8
And the other end of the capacitor 7 as a DC voltage input terminal.
Between the output terminals of the regulator 3 between the input terminals.
DC voltage to be applied.

When the diode 8 is provided as shown in FIG. 4, the electric charge of the capacitor 7 is transferred to a load (battery 4) other than the fuel pump.
And discharge through the load 6), and all the charges in the capacitor 7 are discharged through the fuel pump 5 ,
As shown in FIG.
The average value of the voltage applied to the fuel pump can be further increased as compared with the case where the configuration is adopted .

In the above-described embodiment, a short-circuit type regulator is used. However, a control element such as a transistor is inserted between the rectifier circuit and the load to control the load voltage to a set value or less. The present invention can be applied to a case where a constant voltage regulator or the like for controlling the internal resistance of the element is used. 6A and 6B show voltage waveforms when a constant voltage regulator is used. FIG. 6A shows an output voltage waveform of the rectifier circuit 2, and FIG. 6B shows a voltage waveform of the regulator when the battery is removed. 3 shows an output voltage waveform. Also in this case, when the battery is removed, the output voltage of the regulator falls to zero, so if this voltage is applied to the fuel pump as it is, the discharge amount and discharge pressure of the pump become insufficient, and the fuel injection device operates satisfactorily. I can't let it. to this
On the other hand, as in the present invention, the power supply of the DC motor 5 of the fuel pump is provided.
Connect a capacitor 7 between the terminals and
The cathode of diode 8 is connected to one end on the positive side of
And the anode of the diode 8 and the other end of the capacitor 7
Is the input terminal for the DC voltage applied to the motor,
Even when the terry 4 has been removed, as shown in FIG.
The slipped voltage can be input to the DC motor 5.
Then, the charge of the capacitor 7 passes through loads other than the DC motor 5.
As a result, the fuel pump can be sufficiently driven.

If a capacitor is connected between the power supply terminals of the fuel pump (DC motor) as in the above embodiment, the capacitor can absorb the harmonic components contained in the output voltage of the regulator. The brush and the commutator can be less damaged, and the durability of the electric motor that drives the pump can be improved.

[0033]

As described above, according to the present invention, a capacitor is connected in parallel between the power supply terminals of the DC motor of the fuel pump.
And a cathode at one end on the positive side of the capacitor.
And the other end of the capacitor
As a DC voltage input terminal to be applied to the DC motor,
The charge of the capacitor passes through loads other than the motor of the fuel pump.
To prevent fuel discharge when the battery goes up or is removed.
Can be increased. Therefore, even when the battery goes up or the battery is removed for some reason, there is an advantage that the discharge amount and the discharge pressure of the fuel pump can be sufficiently secured to start and operate the engine.

[Brief description of the drawings]

FIG. 1 shows a connection between a power supply terminal of a motor for driving a fuel pump .
FIG. 3 is a block diagram illustrating a configuration of a drive circuit of a fuel pump to which a capacitor is connected .

FIG. 2 is a diagram showing an example of an output voltage-current characteristic of a magnet type alternator.

[3] The output of the regulator in the case of not connecting the capacitor between the power supply terminal of the output voltage waveform and a fuel pump driving motor of the regulator when connecting capacitor <br/> capacitors between the power supply terminals of the fuel pump driving electric motor FIG. 4 is a waveform diagram showing a comparison with a voltage waveform.

FIG. 4 is a block diagram illustrating a configuration of a fuel pump driving circuit according to an embodiment of the present invention .

FIG. 5 is a circuit diagram showing a configuration example of a rectifier circuit and a regulator used in the embodiment of the present invention.

6A and 6B are waveform diagrams showing an output voltage waveform of a rectifier circuit and a regulator output voltage waveform when a constant voltage regulator is used, respectively, and FIG. 6C is driven through the regulator. FIG. 4 is a waveform diagram showing a waveform of a voltage applied to the fuel pump when the present invention is applied to the fuel pump.

FIG. 7 is a block diagram showing a configuration of a drive circuit of a conventional fuel pump.

FIG. 8 shows waveforms of voltages applied to the fuel pump when a battery is connected in the conventional example, when the battery is removed in the conventional example, and when the battery is removed in the embodiment of the present invention. FIG. 4 is a waveform diagram for comparison.

FIG. 9 is a diagram showing the relationship between the rotation speed and the torque of the fuel pump and the relationship between the current flowing through the fuel pump and the torque, using the applied voltage of the pump as a parameter.

FIG. 10 is a waveform diagram showing a waveform of a voltage obtained from a regulator in a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Generating coil of a magnet generator, 2 ... Rectifier circuit, 3 ... Regulator, 4 ... Battery, 5 ... Fuel pump, 6 ... Other loads, 7 ... Capacitor, 8 ... Diode.

Claims (1)

(57) [Scope of request for utility model registration] 1. A magnet type alternator and an output of the alternator are regulated.
Rectifier circuit and the output of the rectifier circuit
A regulator that outputs a DC voltage limited to
A battery is connected between the output terminals of the regulator.
Between the output terminals of the regulator of the DC power supply
In a fuel pump for an internal combustion engine that supplies fuel to an injector of a fuel injection device using a DC motor driven by a DC voltage as a drive source, a capacitor is connected in parallel between power supply terminals of the DC motor.
And a die at one end on the positive side of the capacitor.
Connect the cathode of the diode and the anode of the diode
The other end of the capacitor and the output terminal of the regulator
A fuel pump for an internal combustion engine, comprising an input terminal for a DC voltage obtained therebetween .