JP3093460B2 - Engine battery-less electronic fuel injection control device - Google Patents

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 battery-less electronic fuel injection control device for a small displacement engine without a battery.

[0002]

2. Description of the Related Art An electronic fuel system in which a fuel injection valve is disposed in an intake system of an engine, and a valve opening time of the fuel injection valve is controlled in accordance with an operation state of the engine to adjust a fuel injection amount. Injection devices are known.

[0003] In recent years, the application of the above-described electronic fuel injection device to a small displacement engine such as a general-purpose engine or an agricultural engine which is manually operated by a rope starter, that is, a recoil starter system without a power supply battery, has begun to be studied. I have.

In an electronic fuel injection system that does not use a battery, a stable operation is performed during operation by electric power supplied from a generator attached to an engine. However, at the time of starting by the recoil starter, the power supply voltage is not sufficient to open the fuel injection valve, and the fuel pressure is lower than that in the normal operation. If the time is controlled, there is a problem that a sufficient fuel injection amount for performing a stable operation cannot be secured.

To solve this problem, Japanese Patent Laid-Open Publication No.
In Japanese Patent Publication No. 28, the following fuel injection device is proposed. This fuel injection device is provided with a starting fuel supply device used only at the time of starting, and an engine starting operation detecting means which operates by a negative pressure in an intake passage when the engine is manually started. When the start of the engine is detected by the engine start operation detecting means, the fuel is supplied to the starting fuel supply device, and the fuel is ejected to the intake passage.

Japanese Patent Application Laid-Open No. 63-259129 discloses the following fuel injection device. In this fuel injection device, the operating power is supplied to the fuel injection valve through a separate path to open the fuel injection valve without controlling the microcomputer until the engine starts to operate on its own. To be injected.

[0007]

The above-described fuel injection device has the following problems. In the recoil starter starting method that does not use a battery, there is a restriction that ignition must be successful within a short time during which the number of revolutions of the flywheel for power generation is equal to or higher than a predetermined value. Also,
At the time of the start operation, the rotation speed is not sufficiently high, so that a sufficient power supply voltage for opening the fuel injection valve cannot be obtained, or the fuel pressure is lower than in the normal operation. In consideration of such characteristics of the recoil starter starting method, the above-described fuel injection device employs a device for improving the startability by setting the air-fuel ratio at the start to be smaller than that at the time of the normal operation.

[0008] When restarting by the recoil starter is repeated due to a failure in starting, a large amount of unburned gas stays in the cylinder. As a result, there is a problem that as the number of times of starting failure increases, ignition becomes more difficult and the engine becomes more difficult to start.

An object of the present invention is to solve the above problems,
It is an object of the present invention to provide a battery-less electronic fuel injection control device for an engine capable of securing an appropriate fuel injection amount at the time of starting without complicating and enlarging the configuration of a small displacement engine without a battery.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and achieve the object, the present invention provides a recoil starter, a fuel injection valve for supplying fuel to an intake passage, and a fuel injection valve according to an operating state of an engine. Valve opening control means for controlling a valve opening time of a fuel injection valve, power supply means for supplying power generated by rotation of a flywheel connected to a crankshaft of an engine to driving and control means of the fuel injection valve, Fuel supply means for supplying fuel pressurized by a mechanical pump driven in conjunction with the rotation of the flywheel to a fuel injection valve; and the number of fuel injections from the start of the start operation by the recoil starter to the start of the engine on its own. And a means for resetting the number of fuel injections stored in the non-volatile memory after the engine has started up in normal operation Storage means for registering correction data for correcting the valve opening time of the fuel injection valve determined by the valve opening control means so as to be shorter as the number of fuel injections stored in the nonvolatile memory is larger. There is a characteristic in that.

[0011]

According to the present invention having the above-described features, even when the start fails and the start operation is repeated, the opening time of the fuel injection valve, that is, the valve opening time, The fuel injection amount is reduced. as a result,
The amount of stagnation of unburned gas due to repetition of the starting operation can be suppressed.

Further, even if the start fails and the power supply voltage drops, the storage data of the number of fuel injections stored in the nonvolatile memory is retained. This stored data is reset to the initial state after the engine starts up in normal operation.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 2 is a diagram showing a configuration of an engine according to one embodiment of the present invention. In the figure, a piston 3 and a spark plug 4 are arranged in a cylinder 2 of an engine 1. An intake valve 6 is provided at an intake port 6 opened at an upper portion 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 for detecting intake air temperature are arranged upstream of the throttle valve 9. Fuel is injected by an injection valve 10 upstream of the throttle valve 9 in 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 and outer circumferences of the flywheel 13, respectively. ing.
At positions facing the first magnet 14, six protrusions 16 a provided on the stator core 16, and protrusions 16 a
And a power generating winding portion composed of a winding 17 wound around the winding.

The first magnet 14 and the power generation winding unit constitute an injection valve driving power supply unit. The winding 17 is connected to a power supply circuit 34 for rectifying and stabilizing a generated voltage, and the power supply circuit 34 is connected to an electronic control unit (hereinafter, referred to as an electronic control unit).
A power supply voltage is supplied to an 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 igniter unit 18 is connected to the ignition plug 4 via a conductor 33. In addition, the ignition device unit 18 in the present embodiment is constituted by a self-triggering 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 disposed above the cylinder 2. A pulley 20a is fixed to a shaft 21 of the cam 20, and a timing belt (not shown) is provided between the pulley 20a and the crankshaft 12, and the cam 20 is driven by 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 TDC timing is provided at a position facing the third magnet 20b.

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

The fuel pressurized by the fuel pump 22 is supplied to the pipe 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
A pipe 29 communicating with the vicinity of the injection hole of the injection valve 10 is connected. Therefore, the injection valve 1 is controlled by the pressure regulator 27.
A part of the fuel is returned to the fuel tank 24 in accordance with the negative pressure near the injection hole of 0, and the pressure of the fuel supplied to the injection valve 10 is adjusted.

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. ECU 30
Controls the opening timing and opening time of the injection valve 10 based on the detection signals of these sensors, outputs an injection valve drive signal to open the injection valve 10, and controls the intake pipe 7. Inject fuel inside.

A recoil starter (not shown) is attached to the outer end of the flywheel 13 to directly rotate the crankshaft 12 by manual operation at the time of starting.

Next, the operation of the engine configured 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 17 by the rotation of the flywheel 13, electric power is supplied to the ECU 30 via the power supply circuit 34, and an ignition plug in the ignition device unit 18 is also provided. A driving voltage is generated, and a voltage is applied to the ignition plug 4.

In the engine 1, a first magnet 14 and a winding 17 for obtaining electric power for driving the injection valve, and a second magnet 15 and an ignition device unit 18 for obtaining electric power for driving the spark plug are independently provided. Therefore, a 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 injection valve 10 and the spark plug 4 can be operated efficiently even with relatively small energy based on the inertial rotational energy of the flywheel 13 without the interference between the ignition operation and the fuel injection operation.

The fuel injection control in the present embodiment will be described with reference to the timing chart of FIG. In the figure, the vertical axis indicates the terminal voltage applied to the coil of the injection valve 10, and the horizontal axis indicates the time from the start of cranking.

When the power supply voltage reaches the operable voltage of the ECU 30 (timing t1), the ECU 30 starts up. Immediately thereafter, the number of startup injections stored in a nonvolatile memory (hereinafter referred to as EEPROM) is read. The start injection time correction coefficient KRES corresponding to the value read from the memory is searched from a table (see FIG. 5) registered in a predetermined memory. Then, the corrected start injection time Tc is calculated by correcting the fuel injection time T for starting at the start injection time correction coefficient KRES. That is, the corrected start injection time Tc is calculated by the following equation. Tc = T × KRES (1) Timing t2 during start operation by the recoil starter
At t3 and t4, the injection valve 10 is opened for the injection time Tc calculated by the above equation (1) using the start injection time correction coefficient KRES read out according to the number of start injections up to that time, and the fuel is opened. Is injected. Note that the fuel injection timings t2 to t4 are determined based on a detection signal from the TDC sensor.

In the first start, the timing t2
Each time the fuel injection operation is performed at t4, the value of the number of fuel injections stored in the EEPROM is increased by "1".

If ignition is not successful in the fuel injection at timings t2 to t4, a second start operation is performed.
In the present embodiment, a second start operation is performed at timing t5. As a result, the ECU 30 starts up at the timing t6, and the start injection time correction coefficient K corresponding to the number of start injections stored in the EEPROM as in the first start.
RES, the fuel injection time T for starting is corrected by the starting injection time correction coefficient KRES, and the corrected starting injection time Tc
Is calculated. In the second start, timings t7 and t7
At 8, t9, the injection valve 10 is opened according to the modified start injection time Tc, and fuel is injected.

In this embodiment, the timings t7 to t8
And the engine has entered its own driving range from timing t10. When the self-powered operation is started, the number of start injections stored in the EEPROM is cleared. During the self-powered operation, the fuel injection time is calculated based on the injection pattern preset for the self-powered operation, and the fuel injection is performed.

Next, the starting injection time correction coefficient KRES will be described with reference to FIG. As shown in the figure, the start injection time correction coefficient KRES corresponds to the number of start injections, and a value is set so that one fuel injection time becomes shorter as the number of start injections increases.

Therefore, in the example shown in FIG.
At the timing t2 in the second start, the number of start injections up to that time is 0, so the start injection time correction coefficient KRE
S “1.0” is read, and at timings t3 and t4,
The start injection time correction coefficient KRES "0.8" is read out corresponding to the start injection times 1 and 2, respectively, and the corrected start injection time Tc is calculated. On the other hand, at timings t7, t8, and t9 in the second start, the start injection time correction coefficient KRES is set to “0.
8 "," 0.6 ", and" 0.6 "are read out.
As a result, at timings t7 to t9, fuel injection is performed based on the corrected start injection time Tc calculated using the start injection time correction coefficient KRES “0.8” to “0.6”.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. FIG. 3A shows a background process that is always repeated in each start operation.
FIG. 4B shows the TDC input from the TDC sensor 19.
4 shows a process performed in response to a detection signal.

First, in step S1 of FIG.
The number of start injections stored in the EPROM is read, and the read value is written to the RAM. The process of step S1 is executed only once in one start operation. In step S2, other background loop processing is executed.

It should be noted that the EEOROM
The value read from the RAM is written to the RAM for the following reason. That is, it takes a relatively long time to read the data stored in the EEPROM. Therefore, in this embodiment, at each fuel injection timing, that is, at each TDC detection, instead of calculating the fuel injection time based on the data stored in the EEPROM, the fuel injection time is calculated based on the data stored in the RAM. Make up. The number of start injections stored in the RAM is updated (incremented) for each fuel injection.

Further, if the power supply voltage drops when starting fails, the data stored in the RAM is erased, so that the number of starting injections is also stored in the EEPROM for each fuel injection (see step S14 to be described later). . Then, at the time of restart after the start failure, the data of the EEPROM is read at the time of startup of the ECU 30, for example, at the timing t6 in FIG. 3, and the data is transferred to the RAM.

In FIG. 4B, in step S10, it is determined whether the engine is running or is operating on its own by determining whether the engine speed exceeds a predetermined speed. Note that the engine speed is calculated based on the detection interval of the TDC detection signal. If it is determined that the engine speed is equal to or less than the predetermined speed and it is at the time of starting, the process proceeds to step S11, and a start time correction coefficient KRES is searched based on the data stored in the RAM.

In step S12, the starting time correction coefficient K
Using RES, the corrected start injection time Tc is calculated by the equation (1). In step S13, the starting injection is performed according to the modified start injection time Tc.

In step S14, the value of the RAM, that is, the number of times of injection is incremented, and the value is transferred to the EEPROM.

On the other hand, if the determination in step S10 is negative, the process proceeds to step S15 to clear the data in the EEPROM, and in step S16, the injection process during the self-powered operation is performed. In the normal injection processing, the valve opening time is determined based on a predetermined injection pattern based on values indicating the engine operation status such as the engine temperature, the engine speed, and the opening degree of the throttle valve.

In the above, an example has been shown in which the fuel injection time for starting is corrected in accordance with the number of times of starting injection. However, for example, the fuel injection time corresponds to the engine temperature at the time of starting. It is also possible to correct the starting fuel injection time T by further multiplying by a temperature correction coefficient for shortening the time. In this case, assuming that the temperature correction coefficient is KT, the corrected start injection time Tc is calculated by the following equation. Tc = T × KRES × KT (2) Next, with reference to the functional block diagram of FIG. 1, the main functions of the ECU 30 for performing the above control will be described. In FIG. 1, a fuel injection number storage unit 35, a correction coefficient storage unit 36,
The starting control unit 100 includes the starting injection time storage unit 37 and the corrected starting injection time calculating unit 38.

The fuel injection number storage section 35 stores the number of fuel injections at the time of starting. When a TDC detection signal is supplied from the TDC sensor 19, the stored data is updated (incremented). In the correction coefficient storage unit 36, a start injection number correction coefficient KRES corresponding to the start injection time is registered. The correction coefficient storage unit 36 calculates a start injection number correction coefficient KRES corresponding to the number of fuel injections supplied from the fuel injection number storage unit 35 and a corrected start injection time calculation unit 38.
Output to

The starting injection time storage section 37 stores the injection valve opening time suitable for starting. The corrected start injection time calculation unit 38 calculates the injection valve opening time T supplied from the start injection time storage unit 37 by the start injection number correction coefficient K.
RES is used to calculate the corrected start injection time Tc. The calculated corrected start injection time Tc is output to the injection valve starting unit 40 every time the TDC detection signal is supplied from the TDC sensor 19. The injection valve activation unit 40 opens the injection valve 10 according to the supplied corrected start injection time.

The rotational speed discriminating section 39 calculates the rotational speed of the engine based on the interval of the TDC detection signal from the TDC sensor 19, and when the rotational speed exceeds a predetermined rotational speed indicating that the vehicle is operating by itself. It is determined whether or not there is. When it is detected that the vehicle is driving by itself, a detection signal is output. The data stored in the fuel injection number storage unit 35 is cleared in response to the detection signal. In addition, the self-powered operation control unit 200 starts scheduled self-powered operation control in response to the detection signal during the self-powered operation, and outputs injection valve opening time data based on this control to the injection valve activation unit 40.

The start-time control unit 100 stores the start injection time correction coefficient KRES supplied from the correction coefficient storage unit 36 as well as the correction coefficient according to the engine temperature supplied from the engine water temperature sensor 32. A water temperature correction table 41 for outputting KT can be provided. As described above, the corrected start injection time can be calculated by further multiplying the correction coefficient KT supplied from the table 41.

[0044]

As is apparent from the above description, according to the present invention, the opening time of the injection valve can be shortened as the number of times of starting injection increases. Since the number of start injections is stored in the non-volatile memory, the stored data is retained even when the start fails and the power supply voltage drops. Therefore, when the recoil starter start operation is repeated in the engine without the battery, the concentration of the mixture supplied to the cylinder is prevented from becoming unnecessarily high, and the startability can be improved.

Further, according to the present invention, when the engine starts to operate on its own, the accumulated number of start injections is cleared, so that in the next recoil starter start operation,
Control can be performed from a completely initial state.

[Brief description of the drawings]

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

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

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

FIG. 4 is a flowchart showing the operation of the embodiment.

FIG. 5 is a diagram illustrating an example of a start injection time correction coefficient.

[Explanation of symbols]

1: engine, 4: spark plug, 7: intake pipe, 1
0: injection valve, 19: TDC sensor, 30: ECU,
Reference Signs List 31: throttle valve opening sensor, 32: water temperature sensor, 35: fuel injection count storage unit, 36: correction coefficient storage unit, 37: start injection time storage unit, 38: corrected start injection time calculation unit, 39: rotation speed discrimination Part, 40 ... injection valve activation part

Continuation of the front page (56) References JP-A-4-43843 (JP, A) JP-A-3-249345 (JP, A) JP-A-60-187732 (JP, A) JP-A-3-229938 (JP) , A) JP-A-63-259142 (JP, A) JP-A-57-172143 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 41/00-41/40 F02D 43/00-45/00

Claims (3)

(57) [Claims] 1. A recoil starter, a fuel injection valve for supplying fuel to an intake passage, valve opening control means for controlling a valve opening time of the fuel injection valve in accordance with an operation state of the engine, and a crankshaft of the engine. Power supply means for supplying electric power generated by rotation of the connected flywheel to driving and control means of the fuel injection valve; and a fuel pump pressurized by a mechanical pump driven in conjunction with the rotation of the flywheel. Fuel supply means for supplying the fuel to the injection valve; and starting operation by the number of fuel injections from the start of the start operation by the recoil starter to the start of the engine to self- operation
A nonvolatile memory that accumulates and stores the number of fuel injections regardless of the number of times, a unit that resets the cumulative number of times of fuel injection stored in the nonvolatile memory after the engine starts up in a normal operation, and a valve opening control unit that is determined by the microcomputer. Storage means for registering correction data for correcting the valve opening time of the fuel injection valve to be shorter as the cumulative number of fuel injections stored in the nonvolatile memory is larger. Batteryless electronic fuel injection control device. 2. A TDC sensor for detecting TDC timing, and means for calculating an engine speed based on an output interval of a TDC detection signal output from the TDC sensor, wherein the engine speed is a preset speed. 2. The system according to claim 1, wherein it is determined whether or not the number of the engine has reached a predetermined number.
A battery-less electronic fuel injection control device for an engine according to any of the preceding claims. 3. The engine according to claim 1, further comprising storage means for registering a temperature correction coefficient set such that the opening time of the fuel injection valve is shortened as the engine temperature increases. Batteryless electronic fuel injection control device.