JP4159040B2 - Electronically controlled fuel injection device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronically controlled fuel injection device for an internal combustion engine, and more particularly to an electronically controlled fuel injection device for a relatively small internal combustion engine that is started by a manual operation or the like without using a starter motor.
[0002]
[Prior art]
A fuel injection valve disposed in an intake system of an internal combustion engine (hereinafter simply referred to as “engine”), and a control device that adjusts the fuel injection amount by controlling the valve opening time of the fuel injection valve in accordance with the operating state of the engine An electronically controlled fuel injection device comprising: Conventional electronically controlled fuel injection devices generally include a fuel injection valve, a control device, and a battery that stably supplies sufficient power to use the fuel pump.
[0003]
On the other hand, there is known an electronically controlled fuel injection device that does not include a battery, in which an engine is started with a recoil starter and power is obtained only from a generator driven by the engine after the start. For example, in the electronically controlled fuel injection device disclosed in Japanese Patent No. 2580367, the rotational inertia energy of the flywheel urged by the recoil starter is efficiently used so that no battery is required.
[0004]
In addition, in Japanese Utility Model Publication No. 8-9393, there is provided a power storage means for accumulating the output of a generator driven by an engine. When the generator output decreases, power is supplied from the power storage means to generate power. There has been proposed a fuel injection device that supplements the engine output.
[0005]
[Problems to be solved by the invention]
When the engine is started, the output of the generator is greatly insufficient. Therefore, in a conventional apparatus that compensates for the shortage with the power from the power storage means, a power storage means with a considerably large power storage capacity is required to cope with this shortage. This invention is made | formed in view of such a situation, The objective is to provide the electronically controlled fuel-injection apparatus which can make an electrical storage means small capacity | capacitance.
[0006]
[Means for Solving the Problems]
The present invention relates to an electronically controlled fuel injection device for an internal combustion engine having a fuel pump, a fuel injection valve, and an ignition device that operate with electric power supplied from a generator as a main power source driven by the engine. An engine starter, a backup battery provided in parallel with the main power source, an engine speed detecting means for detecting the engine speed, the engine speed being equal to or lower than a first speed, and the The fuel pump is operated when an engine speed is equal to or higher than a second speed higher than the first speed, and when the engine speed is equal to or higher than the first speed, the fuel injection valve and A first feature is that it comprises driving means for driving the ignition device at a predetermined interval so that the respective driving timings do not overlap each other.
[0007]
In addition, the present invention has a second feature in that the starting device is a recoil starter, and a second feature in that the backup battery is a nickel cadmium battery charged by the main power source.
[0008]
According to the present invention, while the engine speed is lower than the first speed, only the fuel pump is driven by the power of the backup battery, and when the engine speed reaches the second speed, the fuel pump is It is stopped and the ignition device and the fuel injection valve are driven. When the engine speed becomes equal to or higher than the second speed, sufficient power is supplied from the main power source, so that the fuel pump is driven again.
[0009]
In this way, by suppressing the power consumption at the time of engine startup where sufficient power cannot be obtained, the backup battery that supplies power at the time of startup can be reduced in size. For example, a dry battery can be used.
[0010]
In addition, according to the present invention, excellent general-purpose mounting performance can be obtained for general engine work machines by synergy between simple start operability of the recoil starter and downsizing of the backup battery. Due to the good charging performance of the nickel cadmium battery, the battery is charged after the engine is started, and the holding power for starting can be stably supplied at the next start.
[0011]
Even when the engine fails to start, the fuel pump is driven when the engine speed drops below the first engine speed. Therefore, the engine start operation can be started again by operating the starter quickly.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 2 is a diagram showing a configuration of an engine power generation device according to an embodiment of the present invention. In the figure, a piston 3 and a spark plug 4 are arranged in a cylinder 2 of the engine 1. An intake valve 6 is provided in the intake port 5 that opens to the top of the cylinder 2, and the intake port 5 communicates with the atmosphere via an intake pipe 7 and an air cleaner 8. A throttle valve 9 is provided in the middle of the intake pipe 7. A fuel injection valve (hereinafter simply referred to as an injection valve) 10 and an intake air temperature sensor 11 for detecting the intake air temperature are disposed upstream of the throttle valve 9. The opening degree of the throttle valve 9 is detected by a throttle opening degree sensor 12. A passage 2 b through which cooling water circulates is formed around the cylinder 2, and the cooling water temperature is detected by a water temperature sensor 2 a provided on the wall surface of the cylinder 2.
[0013]
A fuel tank 13 for storing fuel to be supplied to the injection valve 10 is provided, and the fuel tank 13 and the injection valve 10 are connected by a fuel supply pipe 14. A fuel pump 15 is provided in the middle of the fuel supply pipe 14. The fuel pump 15 has a function of adjusting the fuel pressure to a predetermined value and supplying the fuel to the injection valve 10. By this injection valve 10, fuel is injected into the intake pipe 7 on the upstream side of the throttle valve 9.
[0014]
A flywheel 17 having an annular portion is fixed to the crankshaft 16 of the engine 1, and magnets 18 and 19 are attached to the inner periphery of the annular portion of the flywheel 17. A stator core 20 is provided at a position facing the magnets 18 and 19, and a winding 21 is wound around the stator core 20. The magnets 18 and 19, the stator core 20, and the winding 21 constitute a single-phase two-pole generator (main power source) 22. The crankshaft 16 is provided with a connecting part (not shown) for engaging the recoil starter. The recoil starter and its mounting structure are described in, for example, Japanese Patent Laid-Open Nos. 2001-207941 and 2000-328957.
[0015]
The winding 21 is connected to a power supply circuit 23 that rectifies and stabilizes the generated voltage, and the power supply circuit 23 supplies a power supply voltage to an electronic control unit (hereinafter referred to as ECU) 24. Detection signals from the sensors 11, 12, 2a are supplied to the ECU 24.
[0016]
The ECU 24 supplies driving signals to the fuel pump 15, the ignition device 27, and the injection valve 10. In addition, power is supplied to the fuel pump 15, the ignition device 27, and the injection valve 10 through a power supply circuit 23 with a cable (not shown).
[0017]
FIG. 3 is an electrical system diagram including the power supply circuit 23. In the figure, the output of the generator 22 is connected to a power supply circuit 23 via a full-wave rectifier 25. The power supply circuit 23 includes a constant voltage regulator 231 and a transistor 232 that adjust an output voltage input via the full-wave rectifier 25 to a constant voltage (for example, 14.5 volts), a backup battery 233, and a charger 234 thereof. Is provided. The battery 233 is suitably a rechargeable battery, for example, a nickel cadmium battery having a rated voltage of 6 volts. Between the battery 233 and the power supply line L, a backflow preventing diode 235 is provided.
[0018]
The constant voltage regulator 231 controls the transistor 232 so that the output of the full-wave rectifier 25 is less than or equal to a predetermined voltage. The battery 233 is controlled by the ECU 24 so that the charger 234 is turned on and charged by the output of the generator 22 when the charging voltage becomes equal to or lower than a predetermined value (a value lower than 6 volts). An ECU 24, a fuel pump 15, an injection valve 10, an ignition device 27, and an electronic governor 28 for controlling the engine speed are connected to the output side of the power circuit 23 via a power switch 26. The output waveform of the generator 22 is detected by, for example, the constant voltage regulator 231 and input to the ECU 24 for calculation of the rotational speed of the generator 22, that is, the rotational speed NE of the engine 1. The ECU 24 calculates the rotational speed NE of the engine 1 from the frequency of the output waveform. Further, the ECU 24 detects a position where the amplitude of this waveform is zero based on the input output waveform, that is, the rising position of the half-wave waveform of the generator output subjected to full wave rectification. The rising edge of the half-wave waveform is used when determining the operation timing of an electronic control component described later.
[0019]
The power supply circuit 23 can include an external terminal T for connecting an external storage battery, for example, a storage battery 29 having a rated voltage of 12 volts. This is because the storage battery 29 can be connected as an auxiliary when the battery 233 is discharged. The storage battery 29 is connected to the external terminal T via the fuse 30 and the switch 31.
[0020]
FIG. 4 is a diagram illustrating an example of an output waveform of the generator 22. In the figure, the voltage (6 volts) of the battery 233, which is a nickel cadmium battery, is indicated by a line A, and the maximum output voltage (14.5 volts) of the regulator 231 is indicated by a line B. When the engine rotational speed NE is 100 rpm (first rotational speed), the output voltage V1 of the generator 22 rectified by the full-wave rectifier 25 is lower than the voltage line A of the battery 233. When the engine rotational speed NE is 1000 rpm (second rotational speed), the output voltage V2 after rectification of the generator 22 exceeds the voltage line A of the battery 233 and is almost close to the maximum output voltage line B of the regulator 231. ing.
[0021]
In the present embodiment, in consideration of the output of the generator 22 at the time of such low engine rotation, the operation timing of each electronic control component at the time of engine start is controlled as follows. FIG. 1 is a timing chart showing operation timings related to the engine speed NE of the fuel pump 15, the injection valve 10, the ignition device 27, and the electronic governor 28 as electronic control components. In the figure, when the power switch 26 is turned on at timing t1, the fuel pump 15 is driven (turned on). Since the engine 1 is not rotating at this time t1, the voltage of the battery 233 is higher than the potential of the power supply line L. Therefore, power is supplied from the battery 233 to the fuel pump 15 through the diode 235.
[0022]
When the fuel pump 15 is driven, the fuel pressure becomes high and fuel injection becomes possible. Thereafter, the recoil starter is operated to start the engine 1. The engine 1 starts to rotate by the recoil starter, and the fuel pump 15 is stopped (turned off) at a time t2 when the engine speed NE reaches a first speed, for example, 100 rpm. Then, the injection valve 10 and the ignition device 27 are operated to ignite the engine 1. The injection valve 10 and the ignition device 27 are set to have timing and operation time so that they are not driven simultaneously. This is because if both are driven at the same time, the power consumption increases and the power supplied by the battery 233 and the generator 22 is insufficient.
[0023]
If the engine rotational speed NE reaches a second rotational speed, for example, 1000 rpm, it can be determined that the engine 1 has been reliably started, and the output voltage of the generator 22 has increased as described above. Therefore, from timing t3, the fuel pump 15, the injection valve 10, the ignition device 27, and the electronic governor 28 are all operated, and the engine 1 can be rated. As shown in the lowermost stage of FIG. 1, electric power can be suitably supplied from the power supply circuit 23 according to the amount of power consumption at the time of engine start, which varies depending on the operating state of each part.
[0024]
Note that when the engine speed once decreases after exceeding the first speed, that is, when starting fails, the operation of the injection valve 10 and the ignition device 27 is stopped, and the fuel pump 15 is driven. Therefore, even if the start fails, the start operation of the engine 1 can be started again by operating the recoil starter immediately.
[0025]
FIG. 5 is a block diagram showing the main functions of the ECU 24 related to engine start. An engine speed detector 100 and a drive unit 110 are provided for starting the engine. Both engine speed detection unit 100 and drive unit 110 operate when power supply switch 26 is turned on and power supply from power supply circuit 23 is started. The engine speed discriminating unit 100 outputs the detection signal s1 when the engine speed NE exceeds the first speed, and sets the second speed that the engine speed NE is higher than the first speed. When it exceeds, the detection signal s2 is input to the drive unit 110. The drive unit 110 performs a predetermined operation based on the signals s1 and s2 from the engine speed detection unit 100. When the signal s1 is not detected, that is, when it is determined that the engine speed NE is lower than the first speed, the fuel pump 15 is driven. On the other hand, when the signal s1 is detected, that is, when it is determined that the engine speed NE exceeds the first speed, the fuel pump 15 is stopped and the injection valve 10 and the ignition device 27 are driven. . However, the injection valve 10 and the ignition device 27 are driven alternately so that they are not driven simultaneously.
[0026]
When the detection signal s2 is detected, the driving unit 110 determines that the engine 1 is reliably rotating by itself and drives the fuel pump 15, the injection valve 10, the ignition device 27, and the electronic governor 28. If the engine 1 fails to start, the engine speed NE becomes equal to or lower than the first speed and the detection signal s1 disappears, so that only the fuel pump 15 is driven again.
[0027]
The operation timing of the fuel pump 15, the injection valve 10 and the ignition device 27 will be described in further detail with respect to the output voltage of the power supply circuit 23.
[0028]
FIG. 6 is a diagram illustrating the relationship between the output waveform of the full-wave rectifier 25 and the operation timing of the fuel pump 15, the injection valve 10, and the ignition device 27. The operation timing with respect to the output waveform is the same both at the time of starting the engine and at the time of normal operation after the engine complete explosion.
[0029]
In the present embodiment, since the generator 22 is a single-phase two-pole, the output from the full-wave rectifier 25 forms four half-wave waveforms for each rotation of the engine 1. The engine 1 is a four-cycle engine that executes one cycle with two revolutions. The ignition device 27 is charged and discharged, and the injection valve 10 is driven in synchronization with the latter half of the four half-wave waveforms formed during the first rotation, that is, intake and compression. The charging of the ignition device 27, the discharge of the ignition device 27, and the driving of the injection valve 10 are distributed and synchronized in two half-wave waveforms. In charging and discharging of the ignition device 27, charging consumes more power than discharging and consumes little power for discharging operation. This is because discharging merely supplies a trigger signal. In this way, when performing a plurality of operations with a single electronic control component, the operation with the largest power consumption (main operation) is distributed in the same half-wave waveform overlapping the main operation of other electronic control components. So that there is no such thing. For example, charging of the ignition device 27 and driving of the injection valve 10 are operated in synchronization with mutually different half-wave waveforms. Further, the fuel pump 15 is driven in synchronization with the two half-wave waveforms in the latter half of the four half-wave waveforms formed during the second rotation, that is, explosion and exhaust. The operating voltage of the electronic control component such as the injection valve 10 is set so as to match the voltage of the battery 233, for example, the voltage of 6 volts of a nickel cadmium battery.
[0030]
Since charging and discharging of the ignition device 27 and driving of the injection valve 10 are short in time with respect to the half-wave waveform, the voltage value of the voltage line L is 6 volts so as to match the ignition timing of the engine 1, respectively. It may be started at a timing exceeding. For example, when the voltage does not reach 6 volts at the fuel injection timing set separately, the injection valve 10 is driven when the voltage of the voltage line L reaches 6 volts thereafter. When the voltage of the voltage line L has reached 6 volts at the fuel injection timing, the injection valve 10 is immediately driven. Since the period of the half-wave waveform is short (about 4 milliseconds at 3600 rpm), even if the fuel injection timing is slightly shifted in accordance with the half-wave waveform, the operation of the engine 1 is not affected.
[0031]
On the other hand, the fuel pump 15 is set to turn on when the voltage value exceeds a threshold value, for example, 6 volts, after detecting the rising of the half-wave waveform. Thereby, electric power can be efficiently supplied to the fuel pump 15 within the half-wave waveform.
[0032]
The synchronization of the operation of the electronic control component such as the injection valve 10 with respect to the half-wave waveform is not limited to the above example, and any operation may be used as long as power can be efficiently extracted within the half-wave waveform. That is, the operation start timing within each half-wave waveform may be set so that a predetermined operating voltage (for example, 6 volts) can be maintained for a predetermined operating time.
[0033]
In this embodiment, a recoil starter is used as a manually operated engine starter. However, the present invention is not limited to this, and a livestock starter, a kick starter, or the like can be used as appropriate.
[0034]
【The invention's effect】
The backup battery provided in parallel with the main power source can be reduced in size, and even if the start fails, preparation for the restart operation can be performed quickly, so that the engine startability can be improved.
[Brief description of the drawings]
FIG. 1 is a timing chart showing operation timings of electronic control components related to engine speed.
FIG. 2 is a diagram showing a configuration of an engine according to an embodiment of the present invention.
FIG. 3 is a main part electrical system diagram of an engine including a power supply circuit;
FIG. 4 is a diagram showing an example of an output waveform of a generator as a main power source.
FIG. 5 is a block diagram showing functions of an essential part of an ECU related to engine start.
FIG. 6 is a diagram illustrating a relationship between an output waveform of a full-wave rectifier and an operation timing of an electronic control component.
[Explanation of symbols]
1 Engine 7 Intake Pipe 10 Injection Valve 15 Fuel Pump 20 Iron Core 21 Winding 22 Generator (Main Power)
23 power circuit 27 ignition device 233 battery

Claims (2)

In an electronically controlled fuel injection device for an internal combustion engine having a fuel pump, a fuel injection valve, and an ignition device that operate with electric power supplied from a generator as a main power source driven by the engine,
A recoil starter which is a manually operated engine starter ;
A backup battery provided in parallel with the main power supply, and connected to the power supply line by the main power supply via a diode for preventing backflow ;
Engine speed detecting means for detecting the engine speed;
The fuel pump is operated when the rotational speed of the engine is equal to or lower than the first rotational speed and when the rotational speed of the engine is equal to or higher than a second rotational speed higher than the first rotational speed. An internal combustion engine comprising: drive means for driving the fuel injection valve and the ignition device at a predetermined interval so that their drive timings do not overlap each other when the rotational speed is equal to or higher than the first rotational speed. Electronically controlled fuel injection device. 2. The electronically controlled fuel injection device for an internal combustion engine according to claim 1, wherein the backup battery is a nickel cadmium battery charged by the main power source.

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