JP2005330815A - Fuel injection device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery-less fuel injection device for an internal combustion engine capable of injecting sufficient fuel from an fuel injection valve without using a large size generator at a time of engine start. <P>SOLUTION: This device is provided with a fuel injection valve 4 mounted on the internal combustion engine 1, an electric fuel pump 6 driven by output of the generator 20 driven by the internal combustion engine to supply fuel from a fuel tank 5 to the fuel injection valve 4 and a reciprocating pump 10 driven by a kick pedal of a kick starter 2 to supply fuel from the fuel tank 5 to the fuel injection valve 4 when an operation to start the internal combustion engine is performed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel injection device for an internal combustion engine that supplies fuel to an internal combustion engine that includes a starter that is operated manually.

  A fuel injection device for an internal combustion engine is attached to an intake pipe or the like of an internal combustion engine, and supplies fuel to the fuel injection valve from an electromagnetic fuel injection valve (fuel injector) that injects fuel in response to an injection pulse. A fuel pump, a pressure regulator for controlling the pressure (fuel pressure) of fuel supplied from the fuel pump to the fuel injection valve to be constant, and fuel from the fuel injection valve for a predetermined injection time at a predetermined fuel injection timing And a control device that controls the fuel injection valve. When a vehicle or the like driven by an internal combustion engine includes a battery, a battery-driven fuel injection device that drives a fuel pump, a fuel injection valve, and a control device with a battery is used. On the other hand, when supplying fuel to a vehicle not equipped with a battery, such as a small motorcycle or a snowmobile, a generator driven by an engine is used as a power source, and a fuel pump, a fuel injection valve, and a control device are provided. A batteryless fuel injection device that drives is used. For example, Patent Literature 1 and Patent Literature 2 show battery-less fuel injection devices.

In a fuel injection device that drives a fuel pump using a battery as a power source, a turbine-type pump is used as the fuel pump. On the other hand, in the batteryless fuel injection device, when starting the internal combustion engine, the crankshaft of the internal combustion engine is rotated by a starter driven by human power, and the crankshaft is rotated for a short time. Since it is necessary to drive the fuel pump with the output of the generator to increase the pressure of the fuel supplied to the fuel injection valve, the fuel pump is a trochoid type that can discharge a lot of fuel from low speed rotation. A positive displacement pump is used. In addition, the batteryless fuel injection device disclosed in Patent Document 2 uses a plunger-type electric pump as a fuel pump in order to increase the discharge pressure during low-speed rotation.
JP 2002-106397 A JP 2004-3448 A

  In order to supply fuel from the fuel injection valve to the engine when the internal combustion engine is started, it is necessary to increase the fuel pressure applied to the fuel injection valve to a predetermined pressure before starting the fuel injection. When a battery is provided in a vehicle or the like on which an internal combustion engine is mounted, the fuel pump can be driven by the battery, so that the fuel pressure applied to the fuel injection valve before starting the engine can be raised to a predetermined value without any problem. it can.

  However, in the battery-less fuel injection device, when the engine is started, the fuel is output with the output of the generator attached to the engine within a short period of time when the crankshaft of the engine is rotated by the starter operated manually. It is necessary to drive the pump to increase the fuel pressure applied to the fuel injection valve. If the output of the generator is insufficient at the time of cranking, the fuel pressure applied to the fuel injection valve cannot be sufficiently increased, the initial fuel injection amount is insufficient, and the startability of the engine may be deteriorated. In order to ensure the start of the engine, it is necessary to quickly increase the fuel pressure applied to the fuel injection valve at the start of the engine by using a large generator that outputs a high voltage at a low speed as a generator attached to the engine.

  As described above, in the batteryless fuel injection device, it is necessary to use a large generator having a high output at low speed as a generator driven by the engine. Therefore, the engine becomes large and the engine becomes heavy. There was a problem.

  In the fuel injection device, the fuel injection amount is determined on the assumption that the fuel pressure applied to the fuel injection valve is maintained at a specified value. Since it is difficult to raise the fuel pressure applied to the fuel injection valve at the time of ranking to a specified value, the amount of fuel injected at the time of the first cranking becomes insufficient. Especially when the engine is left stopped for a long time, the amount of fuel injected at the time of the first cranking is largely insufficient, and it is often difficult to start the engine with a single start operation. .

  Further, in the conventional fuel-injection device for a batteryless internal combustion engine, it is necessary to increase the number of turns of the generator coil of the generator and generate a sufficiently large output from the generator at the time of low-speed rotation of the engine. If the generator is given the characteristics, the output of the generator will decrease due to the armature reaction during steady operation of the engine. There was a problem that the output could not be taken out and the power generation efficiency during steady operation of the engine was lowered. This means that it is necessary to use a large generator in order to obtain the power generation output necessary to drive various electrical components when the engine is stationary, and drive the generator that generates the required power generation output. This means that the output energy of the engine used to increase the fuel efficiency.

  Furthermore, in a batteryless fuel injection device, a positive displacement pump is used as a fuel pump. However, since the positive displacement pump has a complicated structure and is expensive, there is a problem that the cost of the fuel injection device is increased. . As shown in Patent Document 2, the use of a plunger-type electric fuel pump has also been proposed, but a plunger-type pump can generate a high discharge pressure, but a positive displacement fuel pump or a turbine-type pump. Since the discharge rate is limited compared to conventional fuel pumps, it is necessary to use a large pump to maintain the fuel pressure supplied to the fuel injection valve during high-speed operation of an engine that requires a large amount of fuel. As a result, there is a problem that the power consumed by the fuel pump during steady operation increases.

  Even in a fuel injection device using a plunger-type electric pump, the fuel pressure applied to the fuel injection valve does not reach a specified value unless the output of the generator is increased to some extent when the engine is started. Therefore, even if a plunger type electric fuel pump is used, it is not possible to improve the startability of the engine when the engine is left stopped for a long time.

  An object of the present invention is to provide a fuelless device for a batteryless internal combustion engine that can improve the startability of an engine and increase the power generation efficiency during steady operation of the engine without using a large generator. It is to provide.

The present invention relates to a fuel injection device for an internal combustion engine that supplies fuel to an internal combustion engine equipped with a starter operated by human power.
A fuel injection device according to the present invention is driven by an output of a fuel injection valve that injects fuel into a fuel injection space of an internal combustion engine in response to an injection pulse, and a generator driven by the internal combustion engine, and in a fuel tank. An electric fuel pump that supplies fuel to the fuel injection valve, and a mechanical driving force is applied from the starter when an operation to start the internal combustion engine is performed, and the fuel in the fuel tank is supplied to the fuel injection valve And a mechanically driven fuel pump.

  A kick starter is often used as the starting device. In this case, as the mechanically driven fuel pump, it is preferable to use a reciprocating pump that receives a driving force from a kick pedal of a kick starter and supplies fuel from a fuel tank to a fuel injection valve. The reciprocating pump is a pump that sucks fuel by a reciprocating motion of a piston or a plunger, compresses the fuel to a predetermined pressure, and discharges the fuel. A high discharge pressure can be obtained.

  With the above configuration, since the reciprocating pump operates simultaneously with the start operation to increase the pressure of the fuel applied to the fuel injection valve, a sufficient amount of fuel is supplied at the time of the first fuel injection after the start operation is started. It is possible to improve the startability of the engine by injecting.

  Also, with the above configuration, since the fuel is supplied from the reciprocating pump to the fuel injection valve when the engine starts, the generator does not need to output a high voltage at a low speed, and the rotational speed of the engine increases to some extent. The voltage required for driving the fuel pump may be generated. Therefore, it is possible to reduce the size of the engine by using a smaller generator than the conventional one. In addition, since a required output can be obtained from the generator during steady operation without using a large generator, the power generation efficiency during steady operation of the engine can be increased.

  In a fuel injection device for an internal combustion engine, a fuel injection that determines an amount of fuel to be injected from a fuel injection valve for various control conditions and applies an injection pulse to the fuel injection valve to inject the determined amount of fuel Control means are provided. In a preferred aspect of the present invention, the fuel injection control means is configured to generate an initial injection pulse when the output voltage of the generator reaches a set value after the start operation of the internal combustion engine is started.

  As described above, according to the present invention, there is provided a reciprocating pump that operates with a mechanical driving force applied from a starting device when the engine is started, and the reciprocating pump does not depend on the output of the generator when the engine is started. Since the fuel is supplied to the fuel injection valve, a sufficient amount of fuel is injected at the start of the engine without using a large generator that outputs a high voltage at low speed as a generator. Can be improved.

  Furthermore, according to the present invention, since a smaller generator can be used as compared with the generator used in the conventional batteryless fuel injection device, the engine can be reduced in size and weight. Further, since the required power generation output can be obtained during the steady operation of the engine without increasing the size of the generator, the power generation efficiency during the steady operation of the engine can be increased and fuel consumption can be saved.

  In addition, according to the present invention, it is not necessary to use a positive displacement pump that can obtain a large discharge amount at an extremely low speed rotation as an electric fuel pump, and an inexpensive turbine fuel pump can be used. Even in consideration of this cost, the cost of the fuel injection device can be reduced.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 schematically shows the configuration of the entire system including an internal combustion engine using a fuel injection device according to the present invention, a generator driven by the internal combustion engine, and an electronic control unit (ECU) for controlling the internal combustion engine. It is shown as an example.

  The fuel injection device of the present embodiment is a fuel injection device for an internal combustion engine that supplies fuel to an internal combustion engine with a kick starter that drives a vehicle on which a battery is not mounted. In this embodiment, in response to an injection pulse A fuel injection valve that injects fuel into the fuel injection space of the internal combustion engine, an electric fuel pump that is driven by the output of a generator driven by the internal combustion engine and supplies the fuel in the fuel tank to the fuel injection valve, and a suction port Is connected to the fuel tank through the low-pressure side connection pipe, and the discharge port is connected to the fuel supply port of the fuel injection valve through the high-pressure side connection pipe. When driven, the fuel in the fuel tank is used as the fuel injection valve. When operating the kick pedal of the kick starter to start the internal combustion engine and the reciprocating pump to be supplied, the displacement of the kick pedal is reciprocated to discharge the fuel from the reciprocating pump. The pump drive mechanism that transmits to the driven part of the pump and the amount of fuel to be injected from the fuel injector for various control conditions, and the injection pulse to the fuel injector to inject the determined amount of fuel And a fuel injection control means for providing.

  The fuel injection control means is configured to generate an initial injection pulse when the output voltage of the generator reaches a set value after the start operation of the internal combustion engine is started.

  In FIG. 1, 1 is a single-cylinder four-cycle internal combustion engine. The illustrated internal combustion engine includes a cylinder 1a, a piston 1b, a crankshaft 1c connected to the piston 1b via a connecting rod, an intake port 1d, and an exhaust port. A cylinder head 1f having 1e, an intake valve 1g and an exhaust valve 1h for opening and closing an intake port and an exhaust port, a camshaft 1i driven by a crankshaft 1c, an intake valve 1g as the camshaft 1i rotates, A valve drive mechanism 1j for driving the exhaust valve 1h and an intake pipe 1k connected to the intake port 1d are provided.

  A throttle valve 1m is provided in the intake pipe 1k, and an ISC valve 1n is attached to an air passage that bypasses the throttle valve 1m. The ISC valve 1n is a valve that adjusts the opening area of the air passage that bypasses the throttle valve. By adjusting this ISC valve, the idling speed control (fast idle control) immediately after the engine is started is performed.

  Reference numeral 2 denotes a starting device for starting an internal combustion engine by human power. The illustrated starting device includes a kick pedal 201, a starter gear 202 rotated by the kick pedal, a driven gear 203 attached to the crankshaft 1c, and a starter. The kick starter includes idle gears 204 and 205 provided between the gear 202 and the driven gear 203. A spring for biasing the kick pedal 201 in the direction of the broken line arrow A is provided in order to hold the kick pedal 201 in the original position during a steady state. An operation portion 201a for placing a foot is provided at one end of the kick pedal 201. When the foot is placed on this operation portion and the kick pedal 201 is pushed down in the direction of the solid arrow B against the biasing force of the spring, the crankshaft 1c is rotated clockwise in the drawing to perform cranking when the engine is started.

  A spark plug 3 is attached to the cylinder head of the internal combustion engine 1, and a non-grounded terminal of the spark plug 3 is connected to a secondary coil of the ignition coil IG through a high-voltage cord. An electromagnetic fuel injection valve (fuel injector) 4 is attached to the intake pipe 1k of the internal combustion engine. In this embodiment, the space in the intake pipe of the internal combustion engine is used as the fuel injection space.

  The illustrated fuel injection valve 4 has an injection valve body (injector body) having a fuel injection port at the tip and a fuel supply port near the rear end, and a position (open) for opening the fuel injection port in the injection valve body. Position) and a closing position (closed position), a valve member provided so as to be displaceable, a biasing means that normally biases the valve member to the closed position side, and a drive of the valve member to the open position side And a solenoid to be operated. The fuel injection valve 4 opens the fuel injection port and injects fuel into the intake pipe of the internal combustion engine while a drive current is applied to the solenoid.

  5 is a fuel tank that stores fuel to be supplied to the engine, 6 is an electric fuel pump that supplies the fuel in the fuel tank 5 to the fuel injection valve 4, and the electric fuel pump 6 is driven by the output of a generator described later. . A suction port 6 a of the electric fuel pump 6 is connected to a fuel outflow pipe 5 a provided in the fuel tank 5 through a predetermined pipe. The discharge port 6b of the electric fuel pump 6 is provided with a check valve 6b1 for preventing the reverse flow of fuel to the fuel pump side. One end of the pipe 7 is connected to the discharge port 6b, and the other end of the pipe 7 is connected. A pressure regulator 8 is connected. The portion near the other end of the pipe 7 and the fuel supply port of the fuel injection valve 4 are connected via a fuel supply pipe 9, and the fuel discharged from the fuel pump 6 passes through the pipe 7 and the fuel supply pipe 9 and the fuel injection valve. 4 is given.

  In the present invention, in addition to the electric fuel pump 6, a mechanically driven fuel pump 10 is provided that operates by receiving a mechanical driving force from a starter 2 that starts the internal combustion engine 1. In the illustrated example, a reciprocating pump including a cylinder 11 and a piston 12 fitted in the cylinder 11 is used as the mechanically driven fuel pump 10. In the illustrated example, one end of the operating shaft 14 is connected to the piston 12 via the pin 13, and the other end of the operating shaft 14 is connected to the end opposite to the operating portion 201 a of the kick pedal 201 via the pin 15. ing.

  In this embodiment, when the kick pedal of the kick starter is operated to start the internal combustion engine with the operation shaft 14 and the pins 13 and 15, the displacement of the kick pedal is reciprocated so that fuel is discharged from the reciprocating pump 10. A pump drive mechanism for transmitting to the piston (driven part) of the pump 10 is configured.

  The cylinder 11 of the fuel pump 10 allows the inflow of fuel into the cylinder and the suction port 16 provided with a check valve 16 a that prevents the outflow of fuel from the cylinder 11 and the outflow of fuel from the cylinder 11. A discharge port 17 provided with a check valve 17 a that permits and prevents the fuel from flowing into the cylinder 11 is provided. The suction port 16 is connected to the fuel outflow pipe 5 a of the fuel tank 5 through the pipe 18, and the discharge port 17 is connected to the fuel supply port of the fuel injection valve 4 through the pipe 19 and the fuel supply pipe 9. In this example, a low-pressure side connecting pipe that connects the suction port 16 of the mechanically driven fuel pump 10 to the fuel tank 5 is constituted by the pipe 18, and the discharge port of the fuel pump 10 is formed by the pipe 19 and the fuel supply pipe 9. A high-pressure side connecting pipe connected to the fuel supply port of the fuel injection valve 4 is configured.

  In the mechanically driven fuel pump 10, the displacement of the piston 12 generated when the operation portion 201 a of the kick pedal 201 is pushed down to start the engine reduces the volume of the pump chamber in the cylinder 11. Fuel is discharged from the discharge port 17. When the kick pedal 201 is returned to the original position by the biasing force of the spring, the displacement of the piston 11 increases the volume of the pump chamber, so that the fuel flows from the fuel tank 5 into the cylinder 11. The pump chamber of the mechanically driven fuel pump 10 is always filled with fuel.

  In the illustrated example, a reciprocating pump provided with a piston 12 is used, but a reciprocating pump using a plunger may be used instead of the piston.

  The pressure regulator 8 returns a part of the fuel supplied from the fuel pump 5 to the fuel tank 5 when the fuel pressure applied from the fuel pumps 6 and 10 to the fuel injection valve 4 exceeds a set value, thereby fuel injection. Adjust the fuel pressure applied to the valve to keep it at the set value.

  As described above, since the fuel pressure applied to the fuel injection valve 4 is kept substantially constant, the amount of fuel injected from the fuel injection valve 4 (fuel injection amount) is such that the injection port of the fuel injection valve 4 is open. Determined by time (injection time). The time during which the injection port of the fuel injection valve 4 is open is substantially determined by the time during which the drive current is applied to the fuel injection valve. Therefore, when controlling the fuel injection amount, the fuel injection amount required by the engine for various control conditions is calculated, the injection time required to obtain the injection amount is obtained, and this injection time is invalidated. An injection pulse having a time width obtained by adding the injection time is applied to the solenoid of the fuel injection valve 6 to inject fuel from the fuel injection valve.

  In FIG. 1, 20 is a magnet generator driven by the crankshaft 1c of the engine. The illustrated magnet generator includes a magnet rotor 20a attached to a crankshaft 1c and a stator 20b fixed to an engine case or the like. The magnet rotor 20a includes a flywheel magnet rotor including a cup-shaped flywheel 20c attached to the crankshaft 1c and a plurality of permanent magnets 20d attached to the inner periphery of the flywheel. In the illustrated example, six permanent magnets 20d are attached to the inner periphery of the flywheel, and these permanent magnets are magnetized to, for example, 12 poles to form a magnet field.

  The stator 20b includes a multipolar star-shaped iron core in which a large number of teeth are radially formed and a large number of power generation coils wound around the numerous teeth of the iron core. The magnetic pole part at the tip of each tooth part of the multipolar star-shaped core to be configured is opposed to the magnetic pole part of the magnet rotor 20a via a predetermined gap.

  Reference numeral 21 denotes an ECU (electronic control unit) that controls the fuel injection amount from the fuel injection valve 4 and the ignition timing of the engine. The ECU 21 includes a microprocessor. The ECU 21 includes a rotation speed detection unit that detects the rotation speed of the internal combustion engine by causing the microprocessor to execute a predetermined program, and also includes a fuel pump control unit 21A, an ignition control unit 21B, Various control means such as the fuel injection control means 21C and the fast idle control means 21D are configured.

  Reference numeral 22 denotes a first power supply circuit that applies a power supply voltage to the ECU 21. The power supply circuit rectifies the output voltage Va of the power generation coil provided in the stator of the magnet generator 20, and the output voltage of the rectifier is constant. It is comprised with the regulator controlled so that it may be kept at. Reference numeral 23 denotes a second power supply circuit that converts the output of another power generation coil provided in the stator of the magnet generator 20 into a constant voltage. This power supply circuit is provided in the stator of the magnet generator 20. The rectifier rectifies the output voltage Vb of another power generating coil, and a regulator that controls the output voltage of the rectifier so as to keep it constant. The output of the second power supply circuit 23 is given to the fuel pump 6 through a pump drive circuit provided in the ECU 21 and also supplied to various electric loads 24 mounted on a vehicle driven by the internal combustion engine.

  The ECU 21 receives outputs from various sensors that detect a control condition for controlling the amount of fuel injected from the fuel injection valve 4 and a control condition for controlling the ignition timing of the engine. In the illustrated example, a pressure sensor 25 that detects the pressure in the intake pipe 1k as an intake pipe pressure, an intake temperature sensor 26 that detects the intake temperature of the engine, a water temperature sensor 27 that detects the temperature of cooling water in the engine, A throttle sensor 28 for detecting the opening of the throttle valve 1m is provided, and the output of these sensors is input to the A / D input port of the ECU 21.

  Further, in the vicinity of the flywheel 20c, there is a crank angle sensor 30 that detects the edge of the reluctor 20e formed of a protrusion or a recess formed on the outer periphery of the flywheel 20 and generates a pulse at a specific rotation angle position of the crankshaft. Has been placed. The crank angle sensor 30 includes, for example, an iron core having a magnetic pole portion facing the reluctor 20e at the tip, a permanent magnet magnetically coupled to the iron core, and a signal coil wound around the iron core. When the edge on the front end side in the rotation direction is detected, and when the edge on the rear end side in the rotation direction of the reluctator 20e is detected, pulses having different polarities are generated. The pulse output from the crank angle sensor 30 is given to the microprocessor of the ECU 21 through a waveform shaping circuit (not shown).

  The configuration of various control means provided in the ECU 21 is shown in FIG. In FIG. 2, reference numeral 21E denotes a rotational speed detecting means for detecting the rotational speed of the engine. This rotational speed detecting means reads the measured value of the timer every time the crank angle sensor 30 generates a specific pulse, And a means for calculating the engine rotational speed from the rotational speed detection time data.

  The fuel pump control means 21A includes a pump drive command generating means 21A1 for generating a pump drive command when the engine speed reaches a set value after the microprocessor is started, and an electric fuel when the pump drive command is generated. And a pump drive circuit 21A2 for supplying a drive current to the pump 6.

  The ignition control means 21B includes an ignition timing calculation means 21B1 for calculating the ignition timing of the internal combustion engine with respect to the engine speed, an ignition command generation means 21B2 for detecting the calculated ignition timing and generating an ignition command, An ignition circuit 21B3 having a function of controlling the primary current of the ignition coil so as to cause a sudden change in the primary current of the ignition coil IG when a command is generated. Here, the ignition timing calculation means 21B1 and the ignition command generation means 21B2 are configured by causing a microprocessor to execute a predetermined program, and the ignition circuit 21B3 is configured by a hardware circuit.

  The ignition timing of the engine is calculated in the form of the time that the ignition timer measures while the crankshaft rotates from the position (reference position) where the crank angle sensor 30 generates a specific pulse to the crank angle position corresponding to the ignition timing. The The ignition command generation means 21B2 sets the time for measuring the ignition timing when the reference position is detected from the output pulse of the crank angle sensor 30 to start the measurement, and the ignition timer completes the time measuring operation. An ignition command is generated when The ignition circuit 21B3 controls the primary current of the ignition coil IG in response to the ignition command, and induces a high voltage for ignition in the secondary coil of the ignition coil IG. Since this high voltage is applied to the spark plug 3, a spark discharge is generated in the spark plug, and the engine is ignited.

  The fuel injection control means 21C is an intake air amount estimation means 21C1 that estimates the amount of air sucked into the cylinder of the internal combustion engine from the intake pipe pressure and the rotational speed detected by the pressure sensor 25, and the estimated intake air amount. Basic injection time calculating means 21C2 for calculating the basic injection time of the fuel, injection time correcting means 21C3 for correcting the basic injection time for various control conditions to obtain the actual injection time, and fuel injection start timing Is detected, an injection command generating means 21C4 for generating an injection command having a time width equal to the time obtained by adding the invalid injection time to the actual injection time obtained by correcting the basic injection time, and the injection command is generated. And an injection valve drive circuit 21C5 for supplying an injection pulse equal to the time width of the injection command to the solenoid of the fuel injection valve 4 at this time.

  The intake air amount estimating means may be configured to estimate the intake air amount from the throttle valve opening and the engine speed. Here, the intake air amount estimating means 21C1, the basic injection time calculating means 21C2, the injection time correcting means 21C3 and the injection command generating means 21C4 are configured by causing a microprocessor to execute a predetermined program, and the injection valve drive circuit 21C5 is a hardware. Hardware circuit.

  The fuel injection start timing during steady operation of the internal combustion engine is determined based on the crank angle information obtained from the pulse generated by the crank angle sensor 30 and the stroke of the combustion cycle of the engine. In order to improve the startability of the engine by injecting fuel as soon as possible at the start of the engine, the output voltage of the generator 20 (the output voltage of the first power supply circuit 22) is set after the start operation is started at the start of the engine The injection command generating means 21C4 of the fuel injection control means 21C is configured to generate the first injection pulse when the value is reached and the microcomputer is activated. The injection time for the first fuel injection is set in advance.

  The fast idle control means 21D controls the ISC valve 1n based on various control conditions such as the engine coolant temperature and the intake air temperature so as to control the engine idling speed within an appropriate range.

  As described above, in addition to the electric fuel pump 6, the mechanically driven fuel pump 10 which is operated by being directly supplied with the driving force from the starting device 2 when starting the engine is provided, and the fuel injection valve is provided from this fuel pump. If the fuel is supplied to the fuel injector 4, the fuel is supplied from the mechanically driven fuel pump 10 to the fuel injector 4 before the fuel is supplied from the electric fuel pump 6 to the fuel injector 4 at the start of the engine. Thus, the fuel pressure applied to the fuel injection valve can be increased to a set value.

  FIG. 3 is a time chart showing the fuel injection operation when the engine is started after the engine is left in a stopped state for a long time. In this example, the kick pedal 201 is pushed down at time t1, and the starting operation is started. Immediately after the start operation is started, the fuel pump 10 consisting of a reciprocating pump supplies fuel to the fuel injection valve 4, so that the fuel pressure applied to the fuel injection valve increases as shown in FIG. Since a check valve is provided at the discharge port of the fuel pump 10, the fuel does not flow backward to the fuel pump 10 side, and the pressure in the fuel supply pipe 9 and the pipe 19 connected to the fuel supply port of the fuel injection valve 4. Will rise rapidly. When the pressure of the fuel in the fuel supply pipe 9 and the pipe 19 exceeds the set value, the pressure regulator 8 returns the fuel into the fuel tank 5, so that the fuel pressure applied to the fuel injection valve 4 is kept at the set value.

  FIG. 3B shows the power supply voltage applied to the microprocessor from the first power supply circuit 22 that converts the output voltage of the generator 20 into a constant DC voltage. Since the output voltage of the generator 20 increases with the rotation of the crankshaft by the start operation, the power supply voltage applied to the microprocessor increases. When the power supply voltage reaches the set value Vs at time t2, the microprocessor Starts. The activated microprocessor initializes each part and then generates an injection command Vj having a preset signal width as shown in FIG. As a result, an injection pulse having a signal width equal to the injection command Vj is given to the fuel injection valve 4 from the injection valve drive circuit 21C5. At this time, since the fuel pressure applied to the fuel injection valve 4 has already reached the set value, the amount of fuel set by the fuel injection valve 4 is injected.

  After the first injection command is generated, the microprocessor generates an injection command having signal widths calculated for various control conditions when the injection start timing t3 is detected from the output pulse of the crank angle sensor 30. Then, the second fuel injection is performed. After this second fuel injection, the engine is ignited and the engine is started. When the rotational speed of the engine reaches the set value at time t4 and it is confirmed that the engine is started, the pump drive command generating means 21A1 generates a pump drive command to start the fuel pump 6. As a result, the fuel pressure applied from the fuel pump 6 to the fuel injection valve increases as indicated by the broken line in FIG. In FIG. 3C, Tk represents a time corresponding to the stroke of the kick starter (a time during which cranking is performed by the kick starter). As the kick pedal returns to its original position, the piston of the fuel pump 10 descends, and fuel flows into the fuel pump 10 from the fuel tank 5 in preparation for the next starting operation.

  FIGS. 4A to 4C show an injection command at the time of the second start operation after the engine start failure by the first start operation, the power supply voltage applied to the microprocessor of the ECU, the fuel It shows the fuel pressure applied to the injection valve. The times t1, t2, t3 and t4 shown in FIG. 4 are the time when the starting operation is started, the time when the power supply voltage of the ECU is established and the first injection command is generated, and the microprocessor detects from the output of the crank angle sensor. The injection start timing and the timing at which the electric fuel pump 6 is activated are shown.

  For reference, FIGS. 5 and 6 show time charts showing the operation of the fuel injection device in which fuel is supplied to the fuel injection valve by the electric fuel pump when the engine is started. FIG. 5 is a time chart when a start operation is performed after the engine is left in a stopped state for a long time (when the fuel pressure applied to the fuel injection valve is zero), and FIG. 6 is defined for the fuel injection valve. It is a time chart which shows the operation | movement at the time of performing the starting operation of the 2nd time in the state where this fuel pressure is given.

  In an internal combustion engine using a batteryless fuel injection device in which fuel is supplied from the electric fuel pump to the fuel injection valve during the start operation, when the start operation is performed after leaving the engine stopped for a long time As shown in FIG. 5, the fuel pressure does not increase immediately after the start operation is started at time t1, and the fuel pressure starts to increase after the output voltage of the generator 20 increases and the fuel pump is started. In this state, when the power supply voltage of the ECU reaches a specified value at time t2 and the first injection command is generated, sufficient fuel pressure is not applied to the fuel injection valve, so fuel injection is not performed. The fuel is injected only when the ECU generates a second injection command at time t3. As described above, when fuel is supplied to the fuel injection valve by the electric fuel pump at the time of starting the engine, it takes time until the fuel pressure applied to the fuel injection valve reaches the specified value. The probability that the engine can be started by the operation is lowered, and the startability of the engine is deteriorated. When the starting operation is performed for the second time after the engine has failed to start, as shown in FIG. 6, since the fuel pressure has reached a specified value at the start of the starting operation, the fuel is discharged when the first injection command is generated. Is started, and then the engine is started when an ignition operation is performed.

  As described above, in the fuel injection device according to the present invention, the fuel pressure applied to the fuel injection valve can be increased immediately after the kick pedal starts to be displaced. Therefore, as shown in FIG. Even when the engine is started while the fuel pressure applied to the engine is zero, the fuel pressure applied to the fuel injection valve 4 before the ECU generates an injection command at time t2 is the specified value. Can be reached. Therefore, it becomes possible to supply a sufficient amount of fuel to the engine by the first fuel injection after the start operation is started, and to start the engine with the first kick, and the startability of the engine is improved.

  In the fuel injection device according to the present invention, since the fuel required for starting is supplied to the fuel injection valve 4 from the mechanically driven fuel pump 10 comprising a reciprocating pump, it is not necessary to drive the electric fuel injection pump 6 at the time of starting. Therefore, the output of the generator 20 required when starting the engine can be reduced.

  FIG. 7 shows the relationship between the load current I that can be supplied from the generator to the load through the second power supply circuit 23 and the rotational speed N of the engine. The characteristic of the curve a shown in FIG. This characteristic is required for the generator when fuel is supplied from the electric fuel pump to the fuel injection valve at the time of starting. In order for the generator to have such characteristics, it is necessary to increase the number of turns of the generator coil sufficiently. However, if the number of turns of the generator coil is increased, the output decreases due to the armature reaction during high-speed rotation of the engine. Therefore, the current that can be taken out from the generator during steady operation of the engine is limited. In FIG. 7, No is the maximum value of the rotational speed when cranking is performed, and is the maximum cranking rotational speed when the kick pedal is kicked in an average manner when starting the engine. Ni is the engine idling speed.

  On the other hand, in the fuel injection device according to the present invention, it is not necessary to drive the fuel pump by the generator 20 when the engine is started. Therefore, as the generator, the engine is started as shown by the curve b shown in FIG. After that, it is possible to use one having a characteristic that the load current I flowing through the second power supply circuit 23 rises. Since the generator that suppresses the output during low-speed rotation in this way can generate a large output during high-speed rotation of the engine, it drives the electrical component load during steady operation of the engine even if the generator is configured in a small size. Therefore, it is possible to obtain electric power necessary for the operation, and to increase the power generation efficiency during the steady operation of the engine.

  In the conventional battery-less fuel injection device, it is necessary to use a positive displacement pump (for example, a trochoid pump) that generates a large discharge pressure from the low speed rotation as the electric fuel pump 6, but the positive displacement pump has a structure. It was complicated and expensive. On the other hand, when the engine is configured to supply fuel to the fuel injection valve by a mechanically driven reciprocating pump that operates with a driving force applied from the starter when the engine is started, Since it is no longer necessary to supply fuel from the electric fuel pump to the fuel injection valve during extremely low speed rotation, an inexpensive turbine pump can be used as the fuel pump, and the fuel injection device is still in consideration of the cost of the reciprocating pump. The cost can be reduced.

  In the above embodiment, a single-cylinder internal combustion engine is taken as an example, but the present invention can of course be applied to a fuel injection device provided in a multi-cylinder internal combustion engine having two or more cylinders.

  In the above embodiment, the displacement of the kick pedal is transmitted to the piston 12 of the fuel pump 10 via the operation shaft 14, but the configuration of the pump drive mechanism that transmits the driving force from the starter 2 to the fuel pump 10. The pump drive mechanism can be configured by a cam mechanism including a cam follower attached to a piston and a cam attached to a shaft that rotates when a kick pedal is depressed.

1 is a block diagram schematically showing the hardware configuration of the entire system including an internal combustion engine using the fuel injection device according to the present invention, a generator driven by the internal combustion engine, and a control device for controlling the internal combustion engine. It is. It is a block diagram which shows the whole structure of embodiment of this invention containing the various control means comprised with a microprocessor. 6 is a time chart for explaining the operation of the fuel injection device when the first starting operation is performed after the internal combustion engine using the fuel injection device according to the present invention is left in a stopped state for a long time. . An internal combustion engine in which a fuel injection device according to the present invention is used is left in a stopped state for a long time, and after the first start operation fails to start, the fuel injection device when the second start operation is performed It is a time chart for demonstrating operation | movement. After an internal combustion engine having a fuel injection device using only a fuel pump driven by a generator as a pump for supplying fuel to a fuel injection valve is left in a stopped state for a long time, a first start operation is performed. It is a time chart for demonstrating operation | movement of the fuel-injection apparatus at the time of being performed. An internal combustion engine equipped with a fuel injection device using only a fuel pump driven by a generator as a pump for supplying fuel to the fuel injection valve is left in a stopped state for a long time, and is started by the first start operation. It is a time chart for demonstrating operation | movement of the fuel-injection apparatus at the time of the 2nd starting operation being performed after failing. The output characteristics of the generator required when using the fuel injection device according to the present invention, and the output characteristics of the generator required for the fuel injection device in which fuel is supplied to the fuel injection valve only by the electric fuel injection pump It is the graph which compared and showed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Starter 201 Kick pedal 3 Spark plug 4 Fuel injection valve 6 Electric fuel pump 10 Mechanically driven fuel pump 20 Generator 21 ECU

Claims (4)

A fuel injection device for an internal combustion engine for supplying fuel to an internal combustion engine having a starter operated by human power,
A fuel injection valve for injecting fuel into the fuel injection space of the internal combustion engine in response to an injection pulse;
An electric fuel pump driven by an output of a generator driven by the internal combustion engine and supplying fuel in a fuel tank to the fuel injection valve;
A mechanically driven fuel pump which is supplied with mechanical driving force from the starting device when an operation for starting the internal combustion engine is performed, and supplies fuel in the fuel tank to the fuel injection valve;
A fuel injection device for an internal combustion engine comprising: A fuel injection device for an internal combustion engine for supplying fuel to an internal combustion engine having a starter operated by human power,
A fuel injection valve for injecting fuel into the fuel injection space of the internal combustion engine in response to an injection pulse;
An electric fuel pump driven by an output of a generator driven by the internal combustion engine and supplying fuel in a fuel tank to the fuel injection valve;
A mechanically driven fuel pump which is supplied with mechanical driving force from the starting device when an operation for starting the internal combustion engine is performed, and supplies fuel in the fuel tank to the fuel injection valve;
Fuel injection control means for determining the amount of fuel to be injected from the fuel injection valve for various control conditions, and for applying the injection pulse to the fuel injection valve in order to inject the determined amount of fuel;
Comprising
The fuel injection control means is configured to generate an initial injection pulse when the output voltage of the generator reaches a set value after the start operation of the internal combustion engine is started;
A fuel injection device for an internal combustion engine. The starting device is a kick starter;
The fuel for an internal combustion engine according to claim 1 or 2, wherein the mechanically driven fuel pump is a reciprocating pump that receives a driving force from a kick pedal of the kick starter and supplies fuel from the fuel tank to the fuel injection valve. Injection device. A fuel injection device for an internal combustion engine that supplies fuel to an internal combustion engine with a kick starter that drives a vehicle not equipped with a battery,
A fuel injection valve for injecting fuel into the fuel injection space of the internal combustion engine in response to an injection pulse;
An electric fuel pump driven by an output of a generator driven by the internal combustion engine and supplying fuel in a fuel tank to the fuel injection valve;
The fuel in the fuel tank when the suction port is connected to the fuel tank through the low-pressure side connection line and the discharge port is connected to the fuel supply port of the fuel injection valve through the high-pressure side connection line. A reciprocating pump for supplying the fuel injection valve;
A pump drive mechanism for transmitting a displacement of the kick pedal to a driven portion of the reciprocating pump in order to discharge fuel from the reciprocating pump when the kick pedal of the kick starter is operated to start the internal combustion engine; ,
Fuel injection control means for determining the amount of fuel to be injected from the fuel injection valve for various control conditions, and for applying the injection pulse to the fuel injection valve in order to inject the determined amount of fuel;
Comprising
The fuel injection control means is configured to generate an initial injection pulse when the output voltage of the generator reaches a set value after the start operation of the internal combustion engine is started;
A fuel injection device for an internal combustion engine.

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