JP2007032456A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device for preventing the malfunction of an engine and preventing after-burn as well by surely cutting fuel and reliably discharging generated vapor toward a return passage in a fuel cut control mode for example. <P>SOLUTION: The fuel injection device comprises a fuel injection module 8 for sucking fuel with the reciprocating motion of a plunger 102 and injecting it with pressure, and a control unit 1 for giving a drive signal to the fuel injection module 8. The control unit 1 determines whether the operating condition of the engine E is in a before-start control mode, an idling control mode, or the fuel cut control mode and gives the drive signal to the fuel injection module 8 in each control mode to avoid the event of fuel injection. A time for energizing the drive signal is changed over corresponding to each control mode. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel injection device, and more particularly 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. It is suitable for fuel control.

  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. Fuel injection modules that inject have been proposed. (For example, refer to Patent Document 1).

  The fuel injection module energizes the solenoid coil with the drive signal given from the control unit, and the plunger pressurizes the fuel and injects the fuel at a predetermined fuel pressure. Then, the plunger is pushed back by the spring and is injected next. The fuel is sucked.

  A fuel injection device using a fuel injection module has fewer components than a fuel injection device that pressurizes and regulates fuel with a fuel pump and a regulator and injects pressurized fuel with an injector. Since it is energized only at the time of injection, there is a merit 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 and a battery.

  In addition, this apparatus is provided with a vapor discharge mechanism that recirculates fuel mixed with vapor (bubbles) to a fuel tank by a return pipe before fuel pumped by a plunger pump is injected by an injection nozzle. It has been.

  Further, when in an idling operation state, a fuel cut control mode in which fuel is not injected, or in an operation state in which vapor is likely to be generated in the fuel, such as when it is stopped and the power is turned on, or in a high temperature stop state, FIG. A schematic diagram showing the drive signal and the operation of the fuel injection module in the idle operation state is shown, and the fuel signal between one drive signal and the next drive signal is shown in FIG. By performing pulse energization that does not lead to injection (hereinafter referred to as purge injection or purge injection energization time), the vapor is discharged efficiently and the flow rate of the recirculated fuel is increased to enhance the cooling action. As a result, it has been pointed out that the generation of vapor is suppressed, the fuel injection shown in FIG. 6 (d) is stabilized, and in particular, the restartability is improved. (For example, refer to Patent Document 2).

Japanese Patent Laying-Open No. 2001-221137 (FIG. 14) JP 2003-227432 A (FIGS. 4 and 5)

  FIG. 7 shows the minimum energization time at which fuel of the fuel injection module starts to be injected corresponding to the power supply voltage and the intake pipe pressure for each control mode. As shown in this figure, since the minimum energization time at which the fuel of the fuel injection module starts to be injected varies depending on each power supply voltage and each intake pipe pressure, the pulse energization time that does not lead to fuel injection given to the solenoid coil is set respectively. For example, if the power supply voltage and intake pipe pressure are not switched according to the control mode (pre-startup control mode, idle control mode, fuel cut control mode) When in cut mode, a small amount of fuel oozes out of the fuel injection module, and the fuel burns or does not burn in the cylinder, causing the engine to malfunction, or the cylinder does not burn and reaches the muffler downstream of the engine When the fuel accumulated more than a certain amount, it sometimes exploded (afterburn).

  The present invention has been made to solve the above problems. For example, in the fuel cut control mode, the fuel is surely cut, but the generated vapor is surely discharged toward the return passage, and the engine It is an object of the present invention to provide a fuel injection device that can prevent malfunction and can also prevent afterburning.

  A fuel injection device according to the present invention includes a fuel injection module that sucks and pressurizes fuel by a reciprocating motion of a plunger, and a control unit that gives a drive signal to the fuel injection module. It is determined whether the operation state is a pre-start control mode that is a state before the engine is started, an idle control mode that is an idle operation state, and a fuel cut control mode that is a fuel cut state. In the fuel injection device in which the drive signal is supplied to the fuel injection module so as not to inject fuel, the energization time of the drive signal is switched according to each control mode.

  The fuel injection device according to the present invention is configured as described above, and the pulse energization time of the drive signal applied to the solenoid coil is switched according to the control mode (pre-startup control mode, idle control mode, fuel cut control mode). In particular, in the fuel cut control mode, the pulse energization time is shorter than in the idle control mode, so the fuel is surely cut, but the generated vapor can be reliably discharged toward the return passage, and afterburn Can be prevented.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a configuration diagram showing a state where a fuel injection device according to Embodiment 1 of the present invention is attached to an engine.

The control unit 1 includes an intake air temperature sensor 2 that measures the temperature of the intake air of the engine E, a throttle position sensor 4 that measures the opening of the throttle valve 3, and an intake pressure sensor 5 that measures the intake air pressure downstream of the throttle valve 3. Based on information from the engine temperature sensor 6 for measuring the wall temperature of the engine E and the crank angle sensor 7 for measuring the crank position, an appropriate fuel injection timing and fuel injection amount are calculated and a drive signal is output to the fuel injection module 8 In addition, an appropriate ignition signal is output to the ignition coil 9 based on information from various sensors.

  As shown in FIG. 2, the structure of the fuel injection module 8 is shown in Patent Document 1 or Patent Document 2, and the plunger 102 is driven by electromagnetic force generated by energizing the solenoid coil 101 inside the fuel injection module 8. The fuel supplied from the fuel tank 10 shown in FIG. 1 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 101 is stopped, the plunger 102 is returned to its original position by a return spring (not shown), 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 via the return pipe 13 shown in FIG.

  This will be described in more detail with reference to the schematic view of the fuel injection module 8 of FIG. When energization of the solenoid coil 101 is started by the drive signal from the control unit 1, the plunger 102 moves downward in FIG. 2 and pressurizes the fuel sucked as indicated by an arrow C.

  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 as shown by the arrow a, It flows out of the injection module. Further, 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 to the solenoid coil 101 continues, when the plunger 102 further moves downward in FIG. Is injected into the engine through the injection side check valve 104 and the injection port 105 as indicated by an arrow b.

  Thereafter, when energization of the solenoid coil 101 is completed, fuel is sucked through the suction side check valve 106 as shown by an arrow c when the plunger 102 returns upward in FIG. 2 by a return spring (not shown).

  FIG. 3 is a schematic diagram showing a drive signal (a) for energizing the solenoid coil 101 inside the fuel injection module 8 and an operation (b) 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. After the plunger 102 in the fuel injection module 8 moves and pressurizes the fuel, the fuel is injected at a predetermined pressure. After the energization of the solenoid coil 101 is completed, fuel is sucked when the plunger 102 is returned by a return spring (not shown).

  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 and the throttle operation to the basic injection time for determining the basic injection amount, and further, the invalid injection time is added. This invalid injection time is the time until the fuel is pressurized and injected in the fuel injection module 8 as shown in FIG.

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) in the control unit 1 based on crank angle information detected by the crank angle sensor 7. The

  FIG. 4 is a schematic diagram showing the operation of the fuel injection module 8 in the fuel cut control mode set according to operating conditions such as engine rotation, throttle opening, engine temperature, etc., (a) is a crank angle signal, ( b) is a drive signal for energizing the solenoid coil, (c) is the current of the solenoid coil, and (d) is the state of fuel injection.

  In the fuel cut control mode, as shown in (d), no fuel is injected, but the control unit 1 is based on the crank angle information shown in (a) detected by the crank angle sensor 7 for the invalid injection time. A drive signal is sent to the fuel injection module 8 as shown in (b), and as shown in (c), the solenoid coil 101 is energized to drive the plunger pump, and the above-described vapor discharge mechanism is used. The vapor in the fuel injection module 8 is forcibly discharged out of the fuel injection module, and the electric power is stored in the storage capacitor.

  Next, the purge injection control operation of the first embodiment will be described using the flowchart of FIG. First, the purge injection energization time is set to 0 in step S101, and the process proceeds to step S102. In step S102, it is determined whether or not the control mode is the pre-start control mode based on the engine state.

  When it is determined that the control mode is before starting, the process proceeds to step S103, and the purge injection energizing time is set to XTPRGSTA. If it is determined in step S102 that the control mode is not the pre-startup control mode, the process proceeds to step S104 to determine whether the engine is in the idle control mode based on the engine state.

  When it is determined that the control mode is the idle control mode, the process proceeds to step S105, and the purge injection energization time is set to XTPRGIDL. If it is determined in step S104 that the mode is not the idle control mode, the process proceeds to step S106 to determine whether or not the fuel cut control mode is selected according to the engine state.

  When it is determined that the fuel cut control mode is selected, the process proceeds to step S107, and the purge injection energization time is set to XTPRGFC. Here, when it is not determined in any of the pre-startup control mode, the idle control mode, and the fuel cut control mode, the purge injection energization time remains 0 set in step S101. After the completion of each process, the process proceeds to step S108, where purge injection is performed according to the purge injection energization time, and this routine ends.

  Note that the purge injection energization time XTPRGFC in the fuel cut control mode described above is shorter than the purge injection energization time XTPRGIDL in the idle control mode.

  Since the first embodiment is configured as described above, the pulse energization time (purge injection energization time) that does not lead to fuel injection given to the solenoid coil is set in each control mode (in the pre-startup control mode, idle control). Mode, fuel cut control mode), especially in the fuel cut control mode, because the pulse energization time is shorter than in the idle control mode, the fuel is surely cut, but the generated vapor Can be reliably discharged toward the return passage, so that the engine can be prevented from malfunctioning and afterburn can be prevented.

It is a block diagram which shows the state which attached the fuel-injection apparatus by Embodiment 1 of this invention to the engine. FIG. 3 is a schematic diagram showing the configuration and operation of a fuel injection module according to Embodiment 1. FIG. 3 is a schematic diagram showing a drive signal and an operation of a fuel injection module in the first embodiment. FIG. 6 is a schematic diagram showing a drive signal and an operation of a fuel injection module during fuel cut control in the first embodiment. 3 is a flowchart showing a purge injection control operation in the first embodiment. It is a schematic diagram which shows the drive signal and operation | movement of a fuel-injection module in the conventional idle driving | running state. It is the graph which showed the minimum energization time which the fuel of the fuel-injection module starts injecting in each power supply voltage and each intake pipe pressure according to control mode.

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 Inlet side check valve,
E engine.

Claims (2)

  A fuel injection module that sucks and pressurizes fuel by reciprocating movement of a plunger, and a control unit that gives a drive signal to the fuel injection module, and the control unit is in a state in which the engine is operating before the engine is started. It is determined whether the control mode is a pre-startup control mode, an idle operation mode that is an idle operation state, or a fuel cut control mode that is a fuel cut state, and the drive signal is given to the fuel injection module in each control mode. In the fuel injection device that does not lead to fuel injection, the energization time of the drive signal is switched according to each control mode.   2. The fuel injection device according to claim 1, wherein an energization time of the drive signal in the fuel cut control mode is shorter than an energization time in the idle control mode.

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