JP4138794B2 - Fuel injection device and driving method of fuel injection device - Google Patents

Description

  The present invention relates to a fuel injection device for an engine using a fuel injection module having a function of pressurizing fuel by a reciprocating motion of a plunger and a function of a fuel injection valve, and a method for driving the fuel injection device. It is suitable for use in fuel control of a car engine.

In an electronically controlled fuel injection device that calculates the fuel supply amount according to the engine speed and load and gives a drive signal to the fuel injection valve, the plunger is reciprocated by electromagnetic force to suck and pressurize the fuel. For example, Japanese Unexamined Patent Publication No. 2001-221137 (hereinafter referred to as Patent Document 1) proposes a fuel injection module that injects fuel.
The operation of the fuel injection module disclosed in Patent Document 1 energizes a solenoid coil, which is an electromagnetic drive means of a plunger, with a drive signal given from a control unit, and the plunger pressurizes the fuel and injects it at a predetermined fuel pressure. Thereafter, the plunger is pushed back by the spring and the fuel to be injected next is sucked.
A fuel injection device using such a fuel injection module has fewer components than a fuel injection device in which fuel is pressurized and regulated by a fuel pump and a regulator and fuel is injected by a fuel injector. In addition, since it is energized only at the time of injection, there is an advantage that the average power consumption is small, and it is particularly suitable for a small two-wheeled vehicle having a low capacity of a generator or a battery.

As another conventional device, when the solenoid coil is energized to drive the plunger and stop, the power stored in the solenoid coil (also referred to as charge or charge energy) is supplied to the storage capacitor in the solenoid coil drive circuit. Japanese Patent Application Laid-Open No. 2003-336537 proposes to temporarily store and discharge when the solenoid coil is driven again, and use the charge energy as the driving force of the solenoid coil to improve the response of the solenoid coil. Gazette (hereinafter referred to as Patent Document 2).

  Furthermore, as another conventional device, a vapor discharge mechanism that recirculates fuel mixed with vapor (bubbles) to a fuel tank in advance by a return pipe before fuel pumped by a plunger pump is injected by an injection nozzle. Is provided, and in a driving state in which vapor is likely to be generated in the fuel, such as in an idle driving state, pulse energization that does not lead to fuel injection to the solenoid coil (hereinafter also referred to as purge injection or purge injection energizing time). ), The vapor is efficiently discharged, the flow rate of the returned fuel is increased, and the cooling action is enhanced. Thus, a proposal aimed at stabilizing the fuel injection by suppressing the generation of vapor is disclosed in Japanese Patent Application Laid-Open No. 2003-227432 (hereinafter referred to as Patent Document 3).

JP 2001-221137 A JP 2003-336537 A JP 2003-227432 A

  By the way, in the fuel injection device of the type that re-drives the solenoid using the energy stored in the capacitor as shown in Patent Document 2, when drive control as shown in Patent Document 3 is performed, As shown in FIG. 4, the amount of electricity stored in the storage capacitor self-discharges with time after charging (see FIG. 4 (e)), so the pulse energization start time for fuel injection (hereinafter also referred to as main injection start time) When the pulse energization start time (also referred to as purge injection start time) that does not lead to fuel injection is synchronized with the crank angle signal (FIG. 4A), for example, each drive signal (FIG. 4C )) After driving the plunger, the power stored in the solenoid coil at the time of stoppage is stored in the storage capacitor, and then forcibly discharged when the solenoid coil is driven again. The time from power storage to discharge varies depending on the engine speed, the charge energy at the start of solenoid coil drive varies (FIGS. 4D and 4E), the solenoid coil drive force varies, and fuel injection The quantity was not stable, and the engine sometimes malfunctioned.

  The present invention has been made to solve the problems of the conventional apparatus as described above, and is a drive signal given to a solenoid coil as an electromagnetic drive means, that is, a drive signal that does not lead to fuel injection ( Hereinafter, a pulse energization start time (main injection) of a drive signal (hereinafter also referred to as a main injection drive signal) for injecting fuel from a pulse energization start time (purge injection start time) of a purge injection drive signal). By setting the interval Tc of the (start time) to a fixed time, the amount of charge energy stored in the storage capacitor becomes constant, the driving force of the electromagnetic drive means becomes constant, and the fuel injection amount is supplied stably. It is an object of the present invention to provide a fuel injection device and a method for driving the fuel injection device that can prevent malfunction of the engine.

  A fuel injection device according to the present invention has an electromagnetic drive means for driving a plunger, and a fuel injection module that injects and pressurizes fuel by reciprocating movement of the plunger, and an electromagnetic drive means of the fuel injection module. A control unit that gives a drive signal to inject fuel according to the operating state of the engine, and temporarily stores the electric power stored in the electromagnetic drive means when the drive of the electromagnetic drive means is stopped, and again the electromagnetic drive And a storage capacitor for supplying the stored electric power to the electromagnetic drive means when the means is driven, and the control unit has a function to the fuel injection module when the engine is in a predetermined operation state. The purge injection drive signal that does not lead to fuel injection is given between the main injection drive signals that inject fuel. In the fuel injection device having a function, the control unit includes: an energization start time of a purge injection drive signal that does not lead to the fuel injection; and an energization start time of a main injection drive signal for injecting fuel to be performed next. The interval is configured to be a fixed time.

According to another aspect of the present invention, there is provided a fuel injection device driving method comprising: an electromagnetic drive means for driving a plunger; and a fuel injection module that sucks and pressurizes and injects fuel by reciprocating movement of the plunger; A control unit for giving a drive signal to the electromagnetic drive means to inject fuel according to the operating state of the engine, and temporarily storing the electric power stored in the electromagnetic drive means when the drive of the electromagnetic drive means is stopped. A storage capacitor for supplying the stored electric power to the electromagnetic driving means by discharging when the electromagnetic driving means is driven again, and the control unit is configured to inject the fuel when the engine is in a predetermined operating state. Main injection drive that injects fuel into the module with a purge injection drive signal that does not lead to fuel injection A method of driving a fuel injection apparatus that provide in between No., in about an exhaust line of an engine, the calculated energization time of the main injection drive signal, in about the compression line of the engine, the energization time of the purge ejection driving signal And a drive signal is given to the fuel injection module so that the interval between the energization start time of the purge injection drive signal and the energization start time of the main injection drive signal to be performed next becomes a constant time. It is what I did.

  According to the fuel injection device and the method of driving the fuel injection device of the present invention, the fuel is stored in the storage capacitor at the time of pulse energization (main injection) for injecting fuel after pulse energization (purge injection) that does not lead to fuel injection. Thus, the amount of charge energy becomes constant, the driving force of the electromagnetic driving means becomes constant, the fuel injection amount can be stably supplied, and the engine malfunction can be prevented.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings.
1 is an overall configuration diagram showing a state in which a fuel injection device according to Embodiment 1 of the present invention is attached to an engine.
In FIG. 1, a control unit 1 includes an intake air temperature sensor 2 that measures the temperature of intake air of the engine, a throttle position sensor 4 that measures the opening of the throttle valve 3, and an intake air pressure that measures the intake air pressure downstream of the throttle valve 3. From the information of the atmospheric pressure sensor 5, the engine temperature sensor 6 that measures the wall temperature of the engine, and the crank angle sensor 7 that measures the crank position, an appropriate fuel injection timing and fuel injection amount are calculated, and a drive signal is sent to the fuel injection module 8. Output.
Similarly, an appropriate ignition signal is output to the ignition coil 9 from information from various sensors.

The fuel injection module 8 has, for example, a structure as shown in FIG. 2 to be described later, and moves the plunger with electromagnetic force generated by energizing a solenoid coil that is electromagnetic drive means inside the fuel injection module 8. The fuel supplied from the fuel tank 10 via the feed pipe 11 and the fuel filter 12 is pressurized and injected at a predetermined pressure.
When the energization of the solenoid coil is stopped, the plunger is returned to the original position by the return spring, and at that time, the fuel to be injected next is sucked.
Excess fuel and air (vapor) contained in the fuel are returned to the fuel tank 10 by the return pipe 13.

FIG. 2 is a schematic diagram showing an example of the fuel injection module 8 used in the first embodiment, and the structure and operation thereof will be described in more detail.
When energization of the solenoid coil 101, which is an electromagnetic drive means, is started by the drive signal from the control unit 1, the plunger 102 moves and pressurizes the fuel.
At that time, until the plunger 102 reaches the return passage check valve 103 (invalid injection time), the fuel (gasoline) in the fuel injection module partially passes through the return passage check valve 103 and flows out of the fuel injection module ( a flow).
Furthermore, the vapor in the fuel injection module is also discharged out of the fuel injection module by this flow. (Purge injection control)

  Further, when the drive signal from the control unit 1 continues and energization of the solenoid coil 101 continues, the plunger 102 further moves and exceeds a predetermined pressure, the fuel in the fuel injection module is injected into the injection side. It passes through the check valve 104 and the injection port 105 and is injected into the engine (flow b).

  Thereafter, when energization to the solenoid coil 101 is completed, fuel is sucked through the suction side check valve 106 when the plunger 102 is returned by the return spring (flow c).

FIG. 3 is a schematic diagram showing a drive signal for energizing the solenoid coil 101 inside the fuel injection module 8 (see FIG. 2) and the operation of the fuel injection module 8.
When a drive signal as shown in FIG. 3A is sent from the control unit 1 to the fuel injection module 8 and energization of the solenoid coil 101 in the fuel injection module 8 is started, as shown in FIG. Then, the plunger 102 in the fuel injection module 8 moves to pressurize the fuel, inject the fuel at a predetermined pressure, and suck the fuel when the plunger 102 returns by the return spring after the energization to the solenoid coil 101 is completed. To do.

  The drive signal given to the fuel injection module 8 by the control unit 1 is corrected by the atmospheric pressure, the intake air temperature, the engine temperature, the throttle operation, etc., and the invalid injection time is added to the basic injection time for determining the basic injection amount. . This invalid injection time is the time until the fuel is pressurized and injected in the fuel injection module 8.

Generally, when the intake air temperature or the engine temperature is low and the vehicle is in an accelerating state by a throttle operation, the drive signal time becomes long.
This drive signal is output to the fuel injection module 8 in synchronism with crank rotation at a predetermined timing programmed in advance in a storage device (not shown) of the control unit 1 based on crank angle information detected by the crank angle sensor 7. The

Next, the purge injection and main injection control operations of the first embodiment will be described with reference to the schematic diagram of FIG. 5 and the flowchart of FIG.
This routine is called and executed by the crank angle signal timing.
First, in step S101, the current engine stroke is checked by a method (not shown) to determine whether it is an exhaust stroke.
As a result, if the exhaust stroke is determined, in step S102, for example, a main injection energization time determined by, for example, engine speed, engine temperature, intake pressure, throttle opening, etc. is calculated, and main injection energization starts in step S103. For example, the time is calculated so that the angle from the crank angle becomes an optimum angle obtained experimentally, the main injection is actually performed in step S104, and this routine is terminated.

If it is determined in step S101 that the exhaust stroke is not performed, the process proceeds to step S105 to determine whether the compression stroke is performed.
As a result, if it is determined that the compression stroke has occurred, a purge injection energization time that does not lead to fuel injection is calculated in step S106 (for example, often determined in advance by experiments), and in step S107, for example, the previous exhaust From the crank angle signal timing time of the stroke and the crank angle signal timing time of the current compression stroke, the crank angle signal timing time of the next exhaust stroke is estimated, and then the purge injection energization is performed so that the purge injection is started before a certain time Tc. The start time is calculated, purge injection is actually performed in step S108, and this routine ends.

  If it is determined in step S105 that the compression stroke is not performed, this routine is terminated without doing anything.

FIG. 5 is a schematic diagram illustrating operations such as the coil current of the fuel injection module during the purge injection and the main injection described above. FIGS. 5A to 5E are respectively a crank angle signal and an engine. more operation lines of the drive signal, the coil current, shows a capacitor storage amount.

  In the first embodiment, as shown in FIG. 5, the crank angle signal is described as a large protrusion that generates one pulse per engine revolution, but a multi-projection type crank angle that generates a plurality of pulses per engine revolution. It may be controlled by a signal.

  As described above, according to the fuel injection device of the first embodiment of the present invention, the drive signal given to the solenoid coil as the electromagnetic drive means, that is, the drive signal that does not lead to fuel injection (purge injection drive signal) By setting the interval Tc from the pulse energization start time (purge injection start time) to the next pulse energization start time (main injection start time) of the drive signal (main injection drive signal) for injecting fuel to a fixed time. The amount of charge energy stored in the storage capacitor is constant, the driving force of the electromagnetic driving means is constant, the desired fuel injection amount can be stably supplied, and engine malfunction can be prevented. it can

Embodiment 2. FIG.
In the first embodiment, the main injection energization start time is set to an optimum angle from the crank angle obtained experimentally, and the purge injection energization start time is set to a timing estimated from the preceding and subsequent crank angle signal times. (That is, the main injection center method) As the method of the second embodiment, the main injection energization for injecting fuel is started after a predetermined time from the purge injection energization start time (purge injection center method). Also good.

  In the second embodiment, the period from the purge injection to the main injection can be made constant without being affected by the engine rotation fluctuation.

Further, the purge injection center method may be implemented at the time of low rotation near the idle ring and switched to the main injection center method when the rotation speed increases.
By doing so, it is possible to reduce the variation in the amount of charge energy at the time of low rotation that is easily affected by the amount of charge energy stored in the capacitor for storage, and to give priority to the accuracy of the injection timing when the rotation is high.

It is a whole block diagram which shows the state by which the fuel-injection apparatus in Embodiment 1 of this invention was attached to the engine. It is a schematic diagram which shows an example of the fuel-injection module used in Embodiment 1 of this invention. It is a schematic diagram which shows the drive signal and operation | movement of a fuel-injection module of Embodiment 1 of this invention. It is a schematic diagram which shows operation | movement, such as a coil current of the fuel injection module at the time of the purge injection of a conventional apparatus, and main injection. It is a schematic diagram which shows operation | movements, such as a coil electric current of the fuel injection module at the time of purge injection and main injection of Embodiment 1 of this invention. It is a flowchart which shows the control operation | movement of purge injection and main injection of Embodiment 1 of this invention.

Explanation of symbols

1: Control unit 2: Intake temperature sensor 3: Throttle valve 4: Throttle position sensor 5: Intake pressure sensor 6: Engine temperature sensor 7: Crank angle sensor 8: Fuel injection module 9: Ignition coil 10: Fuel tank 11: Feed pipe 12: Fuel filter 13: Return pipe 101: Solenoid coil 102: Plunger 103: Return passage check valve 104: Injection side check valve 105: Injection port 106: Suction side check valve

Claims (5)

  An electromagnetic drive means for driving the plunger; and a fuel injection module that sucks and pressurizes and injects fuel by reciprocating movement of the plunger; and an electromagnetic drive means for the fuel injection module is supplied with fuel corresponding to the operating state of the engine. A control unit for supplying a drive signal to inject, and when the driving of the electromagnetic driving means is stopped, the electric power stored in the electromagnetic driving means is temporarily stored and discharged when the electromagnetic driving means is driven again. A storage capacitor for supplying the stored electric power to the electromagnetic drive means, and the control unit does not cause fuel injection to the fuel injection module when the engine is in a predetermined operation state. In a fuel injection device having a function of giving a purge injection drive signal between main injection drive signals for injecting fuel The control unit is configured such that the interval between the energization start time of the purge injection drive signal that does not lead to the fuel injection and the energization start time of the main injection drive signal for injecting the fuel to be performed next becomes a constant time. A fuel injection device characterized in that it is configured as follows. The control unit determines the energization start time of the purge injection drive signal that does not lead to fuel injection from the crank angle signal timing time of the previous exhaust stroke and the crank angle signal timing time of the current compression stroke. 2. The fuel injection device according to claim 1, wherein the crank angle signal timing time is estimated, and it is determined to start purge injection a predetermined time Tc before the crank angle signal timing time .   2. The control unit according to claim 1, wherein the control unit starts energization of the main injection drive signal for injecting fuel after a predetermined time from the energization start time of the purge injection drive signal that does not lead to fuel injection. Fuel injection device.   The fuel injection device according to claim 3, wherein the predetermined operation state is a low rotation speed in the vicinity of idling. An electromagnetic drive means for driving the plunger; and a fuel injection module that sucks and pressurizes and injects fuel by reciprocating movement of the plunger; and an electromagnetic drive means for the fuel injection module is supplied with fuel corresponding to the operating state of the engine. A control unit for supplying a drive signal to inject, and when the driving of the electromagnetic driving means is stopped, the electric power stored in the electromagnetic driving means is temporarily stored and discharged when the electromagnetic driving means is driven again. A storage capacitor for supplying the stored electric power to the electromagnetic drive means; and the control unit purges the fuel injection module so as not to inject fuel when the engine is in a predetermined operation state. Driving method of a fuel injection device in which an injection drive signal is given between main injection drive signals for injecting fuel In, in about an exhaust line of an engine, the calculated energization time of the main injection drive signal, in about the compression line of the engine, as well as calculating the energization time of the purge ejection driving signal, the energization start time of the purge ejection driving signal And a drive signal is given to the fuel injection module so that the interval between the energization start time of the main injection drive signal to be performed next and the energization start time is a fixed time. .

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