JP4188964B2 - Fuel injection device - Google Patents

Description

  The present invention relates to a fuel injection device including a fuel injection module that sucks and pressurizes fuel by reciprocating movement of a plunger, and in particular, stably maintains a fuel injection state in various operating states of an engine mounted on a motorcycle or the like. The present invention relates to an electronically controlled fuel injection device.

  As an electronically controlled fuel injection device that calculates the fuel supply amount according to the engine speed and load and supplies the fuel, conventionally, the solenoid coil is energized by a drive signal given from the control unit, Fuel injection modules are widely known that operate the plunger with electromagnetic force generated in the solenoid coil to pressurize the fuel and inject it into the engine, and then suck the next fuel when the plunger is pushed back by the spring. It has been. (For example, refer to Patent Document 1).

  Further, in this fuel injection module, the fuel in which bubbles are mixed (hereinafter referred to as vapor) in the cylinder in which the plunger reciprocates due to the high temperature of the environment or the heat generated by the solenoid coil when the plunger is electromagnetically driven. If this is present in a large amount, the mixing ratio of the injected fuel may be reduced to cause engine malfunction. Therefore, in order to prevent this, a vapor discharge mechanism is provided that recirculates vapor that has previously accumulated in the cylinder toward the fuel tank via the return pipe before the fuel is injected.

  The fuel injection device using the fuel injection module having such a configuration has fewer components compared to a fuel injection device that pressurizes and regulates fuel by a fuel pump and a regulator and injects pressurized fuel from an injector. In addition, there is an advantage that the average power consumption can be reduced because electricity is supplied only at the time of injection, and this advantage is used exclusively for small two-wheeled vehicles with particularly low generator and battery capabilities.

  By the way, when the engine is started again from a high temperature stopped state, a large amount of vapor is likely to be generated in the cylinder in which the plunger reciprocates. By energizing the solenoid coil and operating the plunger for a short time that does not lead to injection, the so-called purge injection is used so that the vapor is efficiently discharged through the return pipe, thereby restarting the engine. There has been proposed a technique for improving the performance (see, for example, Patent Document 2).

  On the other hand, in the fuel injection device provided with the fuel injection module, after the fuel is injected by driving the plunger, the plunger is pushed back by the return spring and is stored in the solenoid coil when sucking the fuel. The electric power is temporarily stored in a capacitor for electric storage provided in the drive circuit of the solenoid coil, and the electric power stored in the capacitor is discharged again when the solenoid coil is driven, and the electric power is used as the driving force for the solenoid coil. Thus, a technique has also been proposed in which the responsiveness of the solenoid coil is increased and the power consumption is reduced (see, for example, Patent Document 3).

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

  Generally, in small motorcycles, the capacity of the generator and the battery is low as described above, and if the vehicle is not operated for a while, the battery may be lifted or, depending on the driver, the battery may be removed. In some cases, the engine is not started by a cell motor (also referred to as a starter) but by kick start by stepping on a kick lever. That is, in the case of the above-described battery rising or no battery, even if the driver turns on the key switch, the fuel injection operation is not performed because the control voltage does not reach the power supply voltage that enables the control unit to operate. Rotation is not performed and operation becomes impossible. Therefore, in this case, the generator is forcibly rotated by performing the kick start, and the control unit can be operated by the generated voltage.

Also, at the time of kick start, the engine rotates several times with the stepping force. During that time, fuel is injected into the engine and ignited by the ignition coil, causing an explosion in the engine cylinder and driving the engine with that driving force. Must be maintained.
However, in the conventional apparatus, when the engine is started as described above, after supplying power to the control unit, the plunger is operated by energizing the solenoid coil for a predetermined period of time so as not to inject fuel. Since so-called purge injection was performed, there was a problem that the engine could not be started at the time of kick start.

Furthermore, in the conventional apparatus, the time interval between the crank angle signals is measured, the current crank angle position and the current stroke are determined, and the fuel is used until it is determined what the current stroke is. Since it did not inject, at the time of kick start, it took time until injection, and the problem that the engine could not be started occurred.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a fuel injection device that can reliably start the engine when there is no battery or when the battery is started (for example, kick start). And

In order to achieve the above object, in the present invention, a fuel injection module having a function of sucking fuel by reciprocating movement of a plunger and pressurizing and injecting the fuel, a generator for generating power by rotating an engine, Various sensors for detecting the operating state of the engine, and a control unit that gives the drive signal of the plunger to the fuel injection module based on the operating state of the engine. Te fuel injector odor which is adapted to discharge the vapor generated in, or before Symbol control unit to the engine rotational speed or immediate start mode in which power supply voltage is equal to or greater than a predetermined value within a predetermined period after the power is supplied If the immediate start mode is determined, the fuel injection is performed immediately without performing the purge injection. It is obtained by the Migihitsuji.

  Further, according to the present invention, when the engine speed becomes equal to or higher than a predetermined value within a predetermined time after power is supplied to the control unit, it is determined that the engine is immediately started, and purge injection is performed at the time of starting the engine. Instead, the solenoid is energized to inject fuel and the plunger is operated (hereinafter referred to as main injection).

  Further, according to the present invention, when the power supply voltage supplied to the control unit becomes equal to or higher than a predetermined value within a predetermined time after the power is supplied to the control unit, the immediate start mode is determined and the engine is started. The main injection is performed without performing the purge injection. Further, when it is determined that the immediate start mode is set, the main injection is performed at the subsequent crank angle signal input timing even if the determination of the current stroke is not completed.

  According to the present invention, it is possible to reliably start the engine when the battery is raised or when the battery is not started (for example, kick start), and fuel injection is always stable in various operating states of an engine mounted on a motorcycle or the like. This has the effect of maintaining the state.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram showing a state where the fuel injection device of the present invention is attached to an engine.
In FIG. 1, reference numeral 1 is a four-cycle engine, 2 is an intake air temperature sensor that detects the temperature of intake air of the engine 1, 3 is a throttle valve, 4 is a throttle opening sensor that detects the opening of the throttle valve 3, 5 is an intake pressure sensor that detects the pressure of intake air downstream of the throttle valve 3, 6 is an engine temperature sensor that detects the wall surface temperature of the engine 1, and 7 is a crank that detects the rotational position of a crankshaft (not shown) of the engine 1. An angle sensor, 8 is a fuel injection module, 9 is an ignition coil, and 10 is a control unit.

  Further, 11 is a fuel tank, 12 is a feed pipe for supplying fuel, 13 is a filter provided in the middle of the feed pipe 12, and 14 is a return pipe for returning vapor generated in the fuel injection module 8 to the fuel tank 11. , 15 is an intake manifold. The fuel injection module 8 injects fuel into an intake manifold 15 connected to the engine 1.

The control unit 10 calculates an appropriate fuel injection timing and fuel injection amount based on the detection outputs of the intake air temperature sensor 2, the throttle opening sensor 4, the intake pressure sensor 5, the engine temperature sensor 6 and the crank angle sensor 7. A drive signal is output to the fuel injection module 8 and an ignition signal is output to the ignition coil 9.
In this embodiment, the fuel injection module 8, the control unit 10, the fuel tank 11, and the pipes 12 and 14 constitute a fuel injection device.

  FIG. 2 is a sectional view showing details of the fuel injection module 8 constituting the fuel injection device. In FIG. 2, 81 is a plunger, 82 is a cylinder, 83 is a solenoid coil, 84 is a fuel injection check nozzle, 85 is an orifice nozzle, 86 is a fuel injection port, 87 is a fuel intake check nozzle, 88 is a return check nozzle, 89 is It is a return passage. The return check nozzle 88 and the return passage 89 constitute a vapor discharge mechanism.

  The solenoid 83 is energized by a drive signal given from the control unit 10. By this energization, the solenoid coil 83 is excited and operates so as to urge the plunger 81. The fuel suction check nozzle 87 communicates with the feed pipe 12, and one end of the return passage 89 communicates with a part of the side wall of the cylinder 82 via the return check nozzle 88, and the other end communicates with the return pipe 14. Has been.

Next, the operation of the fuel injection module 8 having the configuration shown in FIG. 2 will be described with reference to the timing chart shown in FIG.
When energization to the solenoid coil 83 is started by the drive signal given from the control unit 10, the plunger 81 moves downward in FIG. 2 by the electromagnetic force generated in the solenoid coil 83. At that time, during the period until the plunger 81 reaches the return check nozzle 88 provided on the side wall of the cylinder 82, the vapor in the cylinder 82 is connected to the return pipe 14 from the return check nozzle 88 and the return passage 89 constituting the vapor discharge mechanism. Is then returned to the fuel tank 11.

  Further, when energization to the solenoid 83 is continued by the drive signal given from the control unit 10, the plunger 81 continues to move downward and closes the return passage 89 on its side surface, so that the vapor discharge is stopped. The fuel in the cylinder 82 is pressurized. Here, the period T1 until the vapor in the cylinder 81 is exhausted to the outside and the fuel in the cylinder 82 is subsequently pressurized becomes the invalid injection period. When the plunger 81 further moves and the pressure in the cylinder 82 exceeds a predetermined value, the pressurized fuel passes through the fuel injection check nozzle 84, the orifice nozzle 85, and the fuel injection port 86 and is injected into the intake manifold 15. (Period T2 in FIG. 3).

  When the output period T0 of the drive signal given from the control unit 10 elapses and the energization to the solenoid coil 83 is stopped, the plunger 81 moves upward so as to return to the original position by a return spring (not shown) ( Period T3 in FIG. At that time, the fuel supplied from the fuel tank 11 via the feed pipe 12 passes through the fuel check nozzle 87 and is sucked into the cylinder 82.

FIG. 4 is a circuit configuration diagram showing the fuel injection device of the present invention.
In the figure, reference numeral 8 denotes a fuel injection module, which is connected to the control unit 10. Reference numeral 103 denotes a battery, 104 denotes a generator attached to the crankshaft of the engine, and 105 denotes a regulator. The control unit 10 includes a microcomputer 106, a solenoid drive control circuit 107, a solenoid drive FET 108, a discharge control circuit 109, a discharge control FET 110, a capacitor 111, a current detection resistor 112, a solenoid current amplification circuit 113, and a current detection circuit 114. It is configured.

  When the key switch 115 is turned on, the control unit 10 is supplied with current from the battery 103 and starts operating. Then, the microcomputer 106 calculates the amount of fuel to be injected based on the input from the sensor shown in FIG. 1 and sends a signal to the solenoid drive control circuit 107. The solenoid drive control circuit 107 turns on the solenoid drive FET 108 to energize the solenoid 83 of the fuel injection module 8 and drives the plunger 81 to inject fuel. At this time, the microcomputer 106 also sends a signal to the discharge control circuit 109, turns on the discharge control FET 110, and discharges the energy stored in the capacitor 111 via this to the fuel injection module 8 and the driving force of the solenoid 83. To do.

  When a predetermined time elapses after the solenoid 83 is driven, the current detection resistor 112 detects the solenoid energization current, and a signal corresponding to the energization current value is sent to the microcomputer 106 through the solenoid current amplification circuit 113. . The microcomputer 106 calculates a correction value corresponding to the energization current and corrects the solenoid driving time. Further, the microcomputer 106 shuts off the solenoid current by shutting off the solenoid driving FET 108 and at the same time shuts off the discharge control FET 110. The electric energy stored in the solenoid 83 at the time of shut-off is stored in the capacitor 111 so that it is used at the initial stage of the next solenoid drive.

Next, the operation at the time of starting the engine when the battery is normally connected and when the battery is not connected will be described.
FIG. 5 explains the operation of the control unit when the battery is normally connected. The key SW, the cell motor, the crank angle signal, the engine rotation speed, the power supply voltage, the control unit, and the drive signal are correlated with each other. FIG. 6 illustrates the operation of the control unit when the battery is not connected, and similarly shows the interrelated operation states of the respective parts. Here, a state where the engine speed or the power supply voltage is equal to or higher than a predetermined value within a predetermined determination period from the start of operation of the control unit is referred to as an immediate start mode.

  When the battery of FIG. 5 is normally connected, when the driver turns on the key SW, a sufficient power supply voltage is supplied from the battery to the control unit, so that the control unit immediately starts operating. Thereafter, the driver drives the cell motor and starts the engine. The time from when the driver turns on the key SW until the cell motor is driven (approximately 500 ms) is delayed compared to the immediate start determination period (approximately 100 ms) from when the control unit starts to operate. The engine rotation speed does not exceed the immediate start determination rotation speed (approximately 900 r / min) within the determination period.

  Further, since the engine does not rotate until the cell motor is driven, the generator does not start generating power. Therefore, the power supply voltage does not exceed the immediate start determination voltage (approximately 14v) (since the battery is a lead storage battery). 12v), the control unit gives a purge injection drive signal to the fuel injection module 8. Thereafter, the engine starts to rotate by the cell motor, the control unit gives a main injection drive signal to the fuel injection module, the fuel is injected, the ignition device ignites, and the engine rotates up.

  Next, when the battery of FIG. 6 is not connected, even if the driver turns on the key SW, the power supply voltage is not supplied to the control unit, so the control unit does not start any operation. Also, the cell motor does not operate because no power supply voltage is supplied. Then, the driver starts kicking with the kick lever. When the engine is kicked, it starts rotating and immediately reaches a high speed. Then, the generator starts power generation and supplies a power supply voltage to the control unit. The control unit starts operation and checks whether the engine speed and the power supply voltage are equal to or higher than a predetermined value within the immediate start determination period. In this case, the engine rotation speed is already equal to or higher than a predetermined speed (immediate start determination rotation speed).

  In addition, since the battery is not connected, the power generation amount of the generator is supplied almost as it is to the control unit, so that the power supply voltage also rises considerably (about 14-18v) and exceeds the predetermined voltage (immediate start determination voltage). Yes. Therefore, the control unit determines the immediate start mode, and gives the main injection drive signal to the fuel injection module at the subsequent crank angle signal input timing even if the current stroke is not determined, and the fuel is injected. The ignition device ignites, and the engine further rotates.

Furthermore, if the battery is running up, the power supply voltage cannot be supplied to the control unit even if the key SW is turned on, and the cell motor cannot be driven naturally. As in the case where the battery is not connected, the engine speed is not less than a predetermined value within the immediate start determination period after the start of the control unit operation. A main injection drive signal is given to the injection module, fuel is injected, and the ignition device ignites, and the engine further rotates.
As described above, the state of no battery or battery rising is determined based on whether the engine speed or the power supply voltage is equal to or higher than a predetermined value within a predetermined determination period from the start of operation of the control unit as described above. Is determined to be an immediate start mode, and fuel injection is performed immediately without performing barge injection.

  FIG. 7 is a timing chart showing in detail how the control unit at the time of kick start when the battery of the present invention is not connected provides a drive signal to the fuel injection module. In the figure, the drive signals to the fuel injection module are shown in chronological order as to the interrelated operations of the kick pedal, crank angle signal, engine process, power supply voltage, control unit, and engine speed.

  That is, in the figure, when the power supply voltage becomes equal to or higher than the controller operating voltage V1 by driving the kick pedal, the process determining means incorporated in the control unit performs the determining operation of the engine process such as compression, expansion, exhaust, and suction. . This process determination operation starts at t1 and is completed at t2. As the process discriminating means, for example, projections at predetermined intervals are attached to the crankshaft, the input time of each projection is measured by a signal from the crank angle sensor, and the projection number is assigned by calculating the time difference. It is a well-known fact that the intake pipe pressure is detected for each projection, the intake process position is determined from the intake pressure data for each designated projection number, and then each process is assigned to the projection number.

  Now, within the predetermined period after the start of the control unit operation, the engine speed and the power supply voltage are checked as described above, and if any of them exceeds the predetermined value, the immediate start mode is determined and this is determined. Immediately switch to the main injection without performing the purge injection. Further, in the instant start mode, even if the current stroke is not determined, that is, even when the process determination operation is not completed (between t1 and t2), the drive signal 1 is generated at the subsequent crank angle signal input timing. Is generated and main injection is performed.

  Conventionally, since the drive signal 2 is generated at the crank angle signal input timing (after t2) after the above process determination operation is completed, it takes time until injection, and the engine start is delayed. On the other hand, according to the present invention, the engine can be reliably started even when the battery is raised or when the battery is not started (for example, kick start).

It is a lineblock diagram showing the outline of the state where the fuel injection device of the present invention was attached to the engine. It is sectional drawing which shows the outline of the fuel-injection module which comprises a fuel-injection apparatus. It is a timing chart with which it uses for the drive signal output from a control unit, and operation | movement description of the fuel-injection module according to this. It is a block diagram which shows a fuel-injection apparatus. It is a timing chart of the drive signal to the key SW, the cell motor, the engine rotation, the power supply voltage, the control unit, and the fuel injection module for explaining the operation of the control unit when the battery is normally connected. It is a timing chart of the drive signal to the key SW, the kick pedal, the engine rotation, the power supply voltage, the control unit, and the fuel injection module for explaining the operation of the control unit when the battery is not connected. It is the timing chart which showed in detail the mode that the control unit at the time of kick start when the battery of the present invention is not connected gives a drive signal to the fuel injection module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 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 Control unit 11 Fuel tank 12 Feed pipe 13 Fuel filter 14 Return pipe 15 Intake manifold
81 Fuel Injection Module Plunger 82 Fuel Injection Module Cylinder 83 Fuel Injection Module Solenoid Coil 84 Fuel Injection Module Fuel Injection Check Nozzle 85 Fuel Injection Module Orifice Nozzle 86 Fuel Injection Module Fuel Injection Port 87 Fuel Injection Module Fuel Intake Check nozzle 88 Return check nozzle 89 of fuel injection module Return path 103 of fuel injection module Battery 104 Generator 105 Regulator 106 Microcomputer 107 Solenoid drive control circuit 108 Solenoid drive FET
109 Discharge Control Circuit 110 Discharge Control FET
111 Capacitor 112 Current detection resistor 113 Solenoid current amplification circuit 114 Power supply detection circuit 115 Key SW

Claims (3)

A fuel injection module having a function of sucking fuel by reciprocating movement of the plunger and pressurizing and injecting it, a generator for generating power by rotating the engine, various sensors for detecting the operating state of the engine, and an operating state of the engine based Te wherein the fuel injection modules and a control unit providing a driving signal of the plunger, fuel injector odor which is adapted to discharge the vapor generated in the cylinder by performing the purging jet that does not lead to the injection of fuel, above when the engine rotational speed or the power supply voltage within a predetermined period after power is applied before Symbol control unit determines whether the immediate start mode is equal to or greater than a predetermined value, it is determined to immediately start mode A fuel injection device characterized in that fuel injection is performed immediately without performing purge injection.   The fuel injection device according to claim 1, wherein the predetermined determination period is 100 ms.   The control unit includes stroke determination means for determining each stroke of the engine based on information from the various sensors. When it is determined that the engine is in the immediate start mode, the stroke determination means has completed the stroke determination. 3. The fuel injection device according to claim 1, wherein fuel injection is immediately performed at a subsequent crank angle signal input timing even when there is not.

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