JPH062586A - Batteryless electronic fuel injection control device for engine - Google Patents

Abstract

PURPOSE:To facilitate starting by effectively utilizing a small number of fuel injection timings at the time of starting a manually started engine. CONSTITUTION:In a reset action completion detecting part 37, a detection signal of riseup of an ECU is output to a fuel injection valve starting part 38. By this detection signal, the fuel injection valve starting part 38 outputs a start signal S2 to open an injection valve 10. Thus, the first fuel injection is performed regardless of whether provided or not fuel injection timing, that is, TDC pulse. A preset value of a timer 35 is output from a table 41 based on an engine water temperature, and only for this time, the first fuel injection is performed. Fuel injection thereafter is performed in accordance with opening time set in a map memory 36 based on a detection signal S4 of the TDC pulse.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic fuel injection control device for an engine, and more particularly to a batteryless electronic fuel injection control device for a small displacement engine without a battery.

[0002]

2. Description of the Related Art An electronic fuel in which a fuel injection valve is arranged in an intake system of an engine and the opening time of the fuel injection valve is controlled according to the operating state of the engine to adjust the fuel injection amount. Injectors are known.

In recent years, the application of the electronic fuel injection device described above has begun to be considered for a small displacement engine such as a general-purpose engine or an agricultural engine that is manually started by a rope starter, that is, a recoil starter system without mounting a power battery. There is.

In an electronic fuel injection system that does not use a battery, during operation, an electronic control unit (hereinafter referred to as an ECU) including a microcomputer from a generator attached to an engine.
That is, sufficient power is supplied, and stable operation is performed. However, at the time of starting by the recoil starter, sufficient electric power is not supplied to the ECU, so that the fuel injection valve cannot be operated.

The relationship between various parameters at the time of starting and the timing of control signals will be described with reference to FIG. When the cranking by the recoil starter is started, the engine speed Ne increases, the generator output voltage VACG induced by the rotation of the flywheel of the engine also gradually increases, and reaches a constant voltage range over time. After that, when the start is successful, the engine speed Ne is further increased as shown by the solid line a and the engine is driven by itself, and the generator output voltage VACG is maintained at a substantially constant value. When the start fails, the engine speed Ne and the generator output voltage VACG decrease as indicated by the dotted line b.

When the TDC pulse P1 indicating the top dead center is detected at the timing t6, the ECU outputs a fuel injection valve starting signal. When the fuel injection valve activation signal is supplied,
In response to this, a predetermined terminal voltage is applied to the fuel injection valve, a current flows through the valve drive coil to open the valve, and fuel is injected into the intake manifold. As a result, the fuel is ignited at the ignition timing immediately after the fuel injection, and the engine starts self-driving.

By the way, as shown in the figure, the ECU enters the reset operation at the timing t1 when the generator output voltage reaches the minimum operating voltage V _E of the ECU, but since the reset is completed and rises, it takes up to the timing t4. , This E
In the CU, the TDC pulse P1 is not detected at the timing t3 before that. On the other hand, at the subsequent timing t6, since the reset operation of the ECU is completed and rises, the TDC pulse P1 is detected, and in response thereto, the fuel injection valve activation signal is turned on.

As described above, since fuel cannot be injected by the TDC pulse P1 before the ignition timing at the timing t5,
The ignition chance in the starting operation by the recoil starter once is only once at the timing t6 under the generator output voltage shown in FIG. for that reason,
There is a problem that the possibility of successful starting is reduced and the number of repeated starting operations is increased due to unsuccessful starting. In addition,
The fuel injection valve reaches the minimum operating voltage V _J at timing t2.

On the other hand, Japanese Patent Laid-Open No. 63-170528 proposes the following fuel injection device. This fuel injection device is provided with a starting fuel supply device which is used only at the time of starting, and an engine starting operation detecting means which operates by negative pressure in the intake passage when the engine is manually started. When the engine start operation detecting means detects the start of the engine, the fuel is supplied to the starting fuel supply device and the fuel is ejected to the intake passage.

That is, in the fuel injection device, the starting fuel injector is not opened by using the actuator operated by electric power, but is provided upstream of the starting fuel injector by the mechanical force generated by the negative pressure in the intake passage. The valve is opened to supply fuel from the fuel tank to the starting fuel injector.
The fuel tank is provided at a position higher than the starting fuel injector, and fuel is supplied by head pressure.

Further, in JP-A-63-259129, the following fuel injection device is proposed. In this fuel injection device, the operating power is supplied to the fuel injection valve through another path to open the fuel injection valve and inject the starting fuel until the engine starts to operate by itself, regardless of the control of the microcomputer. I am trying to let you.

[0012]

The above fuel injection device has the following problems. First, in the fuel injection device described in the former publication, it is necessary to provide a starting fuel injector, a communicating pipe for negative pressure detection, and a negative pressure operating valve for fuel injection only at the time of starting. In a small displacement engine to which the recoil starter system is applied, an increase in such accessory components not only complicates the fuel supply system but also increases the size of the engine, which is not preferable.

Further, when the fuel is supplied by the head pressure, there is a problem that the fuel supply pressure is not stable. In order to maintain a sufficient fuel supply pressure (fuel pressure) in a stable manner, it is desirable to install a pump that can forcibly pressurize and supply fuel, but when starting the engine in the recoil starter system, a sufficient fuel pressure can be obtained immediately by the pump. It is difficult to secure a sufficient amount of fuel at the time of starting, and therefore, there remains a problem that a sufficient amount of fuel cannot be injected at the time of starting.

On the other hand, in the fuel injection device described in the latter publication, fuel is injected without control of the microcomputer until the engine start is completed after the minimum operating voltage of the fuel injection valve is reached. The fuel supply amount becomes too large, and a large amount of unburned exhaust gas tends to be emitted at the time of starting. Further, when cranking is repeated by restarting operation due to a start failure, a large amount of unburned gas is retained in the cylinder, which causes a problem that ignition difficulty gradually increases.

An object of the present invention is to solve the above problems,
An object of the present invention is to provide a battery-less electronic fuel injection control device for an engine, which can secure an appropriate fuel injection amount at the time of starting without complicating and increasing the size of a small displacement engine without a battery.

[0016]

SUMMARY OF THE INVENTION The present invention for solving the above-mentioned problems and for achieving the object is achieved when a flywheel connected to a crankshaft of an engine is rotated by a starting operation by a recoil starter. And a fuel supply means for supplying fuel pressurized by a mechanical pump driven in association with the rotation of the flywheel to the fuel injection valve. And, when it detects that the microcomputer controlling the fuel injection valve has started up, it opens the fuel injection valve immediately, and at the planned fuel injection timing after the microcomputer starts up, the valve opening time based on the planned injection pattern It is characterized in that it is provided with a means for controlling the fuel injection valve so as to inject fuel according to the above.

[0017]

According to the present invention having the above characteristics, the starting fuel is injected immediately after the microcomputer starts up regardless of whether or not the fuel injection timing detection signal is input at the beginning of cranking. Since the fuel injection is performed after the microcomputer starts up, the valve opening time can be controlled and the fuel can be injected without missing the few ignition timings within the cranking time.

Further, when the microcomputer starts up, the generator output voltage is also high, and the energy emitted from the igniter is sufficient for ignition. Therefore, even if the starting fails, the amount of unburned gas remaining is small. .

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. FIG. 2 is a diagram showing a configuration of an engine according to an embodiment of the present invention. In the figure, a piston 2 and a spark plug 4 are arranged in a cylinder 2 of an engine 1. An intake valve 5 is provided in an intake port 6 opening to the upper part of the cylinder 2, and the intake port 6 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, and a fuel injection valve (hereinafter, simply referred to as an injection valve) 10 and an intake air temperature sensor 11 that detects an intake air temperature are arranged upstream of the throttle valve 9. Fuel is injected by the injection valve 10 on the upstream side of the throttle valve 9 of the intake pipe 7.

A flywheel 13 is fixed to a crankshaft 12 of the engine 1, and six first magnets 14 and one second magnet 15 are attached to the inner circumference and the outer circumference of the flywheel 13, respectively. ing.
Six convex portions 16 a provided on the stator core 16 and a convex portion 16 a are provided at a position facing the first magnet 14.
A power generation winding portion including a winding wire 17 wound around is disposed.

The first magnet 14 and the power-generating winding portion form a power source portion for driving the injection valve. The winding wire 17 is connected to a power supply circuit 34 that rectifies and stabilizes a generated voltage, and the power supply circuit 34 is an electronic control unit (hereinafter, referred to as
The power supply voltage is supplied to the ECU 30).

On the other hand, an ignition device unit 18 including an ignition coil is provided at a position facing the second magnet 15. The ignition device unit 18 is connected to the spark plug 4 via a lead wire 33. The ignition device unit 18 in this embodiment is composed of a self-trigger ignition device.

A fuel pump 22 for pressurizing the fuel supplied to the injection valve 10 and a cam 20 for driving the fuel pump 22 are arranged above the cylinder 2. A pulley 20a is fixed to a shaft 21 of the cam 20, a timing belt (not shown) is installed between the pulley 20a and the crankshaft 12, and the cam 20 is driven by the rotation of the crankshaft. A third magnet 20b is provided on the outer peripheral surface of the pulley 20a, and a TDC sensor 19 for detecting the TDC timing is provided at a position facing the third magnet 20b.

The inlet side of the fuel pump 22 is connected to the fuel tank 24 via a pipe line 23, and the outlet side of the fuel pump 22 is connected to the injection valve 10 and the pressure regulator 27 via a pipe line 26. A fuel filter 25 is provided at the tip portion of the pipe line 23 opening to the fuel tank 24, and the fuel in the fuel tank 24 is supplied to the fuel pump 22 via the fuel filter 25 and the pipe line 23.

The fuel pressurized by the fuel pump 22 is supplied to the conduit 2
6 to the injection valve 10. The pressure regulator 27 has a negative pressure chamber 27b and a fuel chamber 27a defined by a diaphragm 27c having a valve body. Fuel chamber 2
7a is connected to the pipe 26 and a pipe 28 communicating with the fuel tank 24, and the negative pressure chamber 27b is connected to the intake pipe 7.
A pipe line 29 communicating with the vicinity of the injection hole of the injection valve 10 is connected. Therefore, the pressure regulator 27 causes the injection valve 1
A part of the fuel is returned to the fuel tank 24 according to the negative pressure near the injection hole of 0, and the pressure of the fuel supplied to the injection valve 10 is adjusted.

Further, the engine 1 is provided with a throttle valve opening sensor 31 for detecting the opening of the throttle valve 9 and an engine water temperature sensor 32 for detecting the cooling water temperature of the cylinder 2. The detection signals of these sensors 31, 32 are supplied to the ECU 30 together with the detection signals of the intake air temperature sensor 11 and the TDC sensor 19. ECU30
Controls the valve opening timing and valve opening time of the injection valve 10 based on the detection signals of these sensors. The injection valve drive signal is output to open the injection valve 10 to operate the intake pipe 7 Fuel is injected into the inside.

Further, a recoil starter (not shown) is attached to the outer end on the flywheel 13 side in order to directly rotate the crankshaft 12 by manual operation at the time of starting.

Next, the operation of the engine constructed as described above will be described. When the flywheel 13 fixed to the crankshaft 12 is rotated by manually operating the recoil starter, the cam 20 rotates and the fuel pump 22 is driven to pressurize the fuel. Simultaneously with the pressurization of the fuel, a voltage is generated in the winding wire 17 by the rotation of the flywheel 13, electric power is supplied to the ECU 30 through the power supply circuit 34, and the ignition coil in the ignition device unit 18 also has an ignition plug. A driving voltage is generated and the voltage is applied to the spark plug 4.

In the engine 1, a first magnet 14 and a winding wire 17 for obtaining electric power for driving an injection valve, a second magnet 15 for obtaining electric power for driving an ignition plug, and an ignition unit 18 are independently provided. The large fluctuation of the power supply voltage of the ignition device for each ignition operation does not directly affect the power supply voltage for driving the injection valve. Therefore, the ignition operation and the fuel injection operation do not interfere with each other, and the injection valve 10 and the ignition plug 4 can be efficiently operated even with the energy of relatively small electric power based on the inertial rotation energy of the flywheel 13.

The fuel injection control in this embodiment will be described with reference to the timing chart of FIG. In the figure, reference numerals t1 to t indicating the time from the start of cranking.
Reference numeral 7 indicates the same timing as the same reference numeral in FIG.

The ECU 30 starts the reset operation at the timing t1 and completes the reset at the timing t4 to complete the EC.
When U30 rises, the fuel injection valve activation signal is immediately turned on, and in response to the activation signal, the fuel injection valve terminal voltage is applied to the coil of the injection valve 10 and fuel is injected. This first fuel injection is continued for a time T1, the fuel injection valve starting signal is once turned off, and then the fuel injection valve starting signal is turned on in response to the TDC pulse P1 at the first timing t6 after the rise of the ECU 30. , Fuel is injected only during time T2.

If the ignition is succeeded at the ignition timing t5 or t7 by these two fuel injections, the engine starts up, and thereafter, the preset timing, that is, TDC.
Every time the pulse P1 is detected, the throttle valve opening sensor 3
1. On the basis of the detection signal of each sensor such as the engine water temperature sensor 32, the injection valve 10 is opened and the fuel is injected only for the time according to the data stored in the map memory in advance.

The fuel injection time T1 is set by the time setting of the timer. For example, the time set value of this timer is
It is determined by a function of the temperature of the cooling water in the cylinder 2 detected by the engine water temperature sensor 32. That is, when the cooling water temperature is high, a short time is set to reduce the fuel injection amount, and when the cooling water temperature is low, a long time is set to increase the fuel injection amount.

Further, the fuel injection time T1 is the detection timing t of the first TDC pulse P1 after the rise of the ECU 30.
The time may be set to be continuous with the fuel injection time T2 after 6, or an appropriate time up to the timing t6 may be set in advance.

Next, referring to the functional block diagram of FIG.
A main function of the ECU 30 for performing the above control will be described. In FIG. 1, the timer 35 has a fuel injection time T
1 is set. The time set in the timer 35 is a value read from the time table 41 based on the water temperature of the cylinder 2 detected by the engine water temperature sensor 32, that is, the engine temperature. The injection time T2 set in the map memory 36 is a function of the engine temperature, the rotation speed, and the intake air amount.

The reset operation completion detecting section 37 is connected to the ECU 3
When the completion of the reset operation of 0 is detected, the detection signal s1 is output to the fuel injection valve starting unit 38. This detection signal s
In response to 1, the fuel injection valve starting unit 38 outputs the starting signal s2 to the terminal voltage supply unit 39. In this way, a predetermined terminal voltage is supplied from the terminal voltage supply unit 39 to the coil of the injection valve 10, and fuel injection is performed. The timer 35 also operates in response to the start command signal s1 and outputs the time-up signal s3 after a predetermined time (T1). This time-up signal s3
Accordingly, the fuel injection valve starting unit 38 stops outputting the start signal s2, and the injection valve 10 is closed.

When the TDC pulse detecting section 40 detects the TDC pulse, the TDC pulse detecting section 40 causes the map memory 3
The detection signal s4 is output to 6. The map memory 36 outputs predetermined time information to the fuel injection valve starting unit 38 in response to the detection signal s4. According to this time information, the fuel injection valve starting unit 38 outputs the start signal s2 and the injection valve 10 opens. Thus, after the timer 35 has timed out, fuel is injected at a predetermined injection timing based on the data read from the map memory 36 each time the TDC pulse is detected.

The timer 35 resets the timer value when the generator output voltage drops below a predetermined value, and again when the generator output voltage rises above the predetermined value, the time table 41.
Read the time corresponding to the cooling water temperature at that time.
The value set in the time table 41 is changed according to the number of repetitions of the starting operation performed until the engine is successfully started and the engine speed becomes equal to or higher than the predetermined number of revolutions. You may comprise. By doing so, the amount of unburned gas retained can be suppressed even if starting failures are repeated.

As described above, in this embodiment, EC
Immediately after the reset operation of U30 is completed, that is, immediately after the start-up of the microcomputer, the starting fuel can be injected.

Although the present invention is particularly effective for a single-cylinder engine which has a small ignition chance in one cranking, it has a great effect in improving the startability even in a multi-cylinder engine.

[0041]

As is apparent from the above description, according to the present invention, regardless of whether or not it is the fuel injection timing based on the sensor input, the fuel is injected immediately after the rise of the microcomputer is detected, and then the fuel is injected. In addition, when the fuel injection timing based on the sensor input is obtained, the fuel injection can be performed at the regular timing according to the sensor input. In this way, without missing a few ignition opportunities,
Effective fuel injection for successful starting can be performed.

Instead of injecting fuel immediately after the start of the cranking operation by the recoil starter, the fuel is injected after the microcomputer starts up and the output voltage of the generator also increases, that is, while the conditions for ignition are being established. I decided to do it. Therefore, even if cranking is repeated due to a start failure, the amount of unburned gas retained is small, and the generation of unburned exhaust gas at the time of starting can be suppressed.

Further, according to the present invention, the above-mentioned starting performance can be improved without complicating the structure of the fuel supply system, so that a small displacement engine such as a recoil starter system is adopted. Even if it is applied to a general-purpose engine, it does not impair the characteristics of small size, light weight, and simple structure.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main function of an ECU.

FIG. 2 is a configuration diagram of a general-purpose engine showing an embodiment of the present invention.

FIG. 3 is a timing chart showing the operation of the embodiment.

FIG. 4 is a timing chart showing the operation of the conventional device.

[Explanation of symbols]

1 ... Engine, 4 ... Spark plug, 7 ... Intake pipe, 1
0 ... Injection valve, 19 ... TDC sensor, 30 ... ECU,
31 ... Throttle valve opening sensor, 32 ... Water temperature sensor, 35 ... Timer, 36 ... Map memory, 37 ...
Reset operation completion detector, 38 ... fuel injection valve starter,
39 ... Terminal voltage supply unit, 40 ... TDC pulse detection unit

Claims (5)

[Claims] 1. When a flywheel connected to a crankshaft of an engine is rotated by a start operation by a recoil starter, power supply means for supplying electric power generated by the rotation for driving and controlling a fuel injection valve, It was confirmed that the fuel supply means for supplying fuel pressurized by the mechanical pump driven by the rotation of the flywheel to the fuel injection valve and the microcomputer equipped in the control means for controlling the fuel injection valve started up. The fuel injection valve is opened for a predetermined time in response to the detection signal of the detecting means and the means for detecting the start-up of the microcomputer, and at the subsequent scheduled fuel injection timing, the fuel injection is performed according to a preset injection pattern. A fuel injection valve control means configured to open the valve for fuel injection A batteryless electronic fuel injection control device for an engine, characterized by: 2. The battery-less electronic fuel injection control device for the engine according to claim 1, wherein the scheduled time is a time set in advance by a timer. 3. The time set by the timer is set so that the valve open state of the injection valve is maintained until the scheduled fuel injection timing after the set time has elapsed. -Less electronic fuel injection control system for the engine. 4. The battery-less electronic fuel injection control device for an engine according to claim 2, wherein the time set in the timer is determined based on a cooling water temperature of the engine. 5. The time set in the timer is determined based on the number of times the starting operation is repeated until the engine speed reaches or exceeds a predetermined engine speed. -Less electronic fuel injection control system for the engine.