JP2001065389A - Fuel injector for cylinder direct fuel injection type two- cycle internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the starting performance in the restart of an internal combustion engine by executing the fuel pressure lowering control in stop, for lowering a value of the fuel pressure to a value lower than a target value for stationary operation when an internal combustion engine is stopped in the control of the fuel pressure of a fuel injector in the cylinder direct fuel injection type two-cycle internal combustion engine. SOLUTION: This fuel injector including a high-pressure fuel pump 6 for supplying the fuel to an injector 3 capable of directly injecting the fuel into a cylinder of two-cycle internal combustion engine 1, is provided with a pressure regulator 15 for holding the fuel pressure to be applied to the injector 3 to an adjusted value, and a timing for starting the fuel injection, and a fuel injection time are controlled by an ECU 30. On this occasion, the ECU 30 is provided with a fuel pressure lowering control means in stop, for controlling the pressure regulator 15 so that a value of the fuel pressure to be applied to the injector 3 is lowered to a value lower than the fuel pressure at the stationary operation of the internal combustion engine 1 in a process for stopping the internal combustion engine 1, which prevents the excess and short fuel injection amount in the starting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device used in a direct injection type two-stroke internal combustion engine in which fuel is injected directly into a cylinder from an injector, and a fuel pressure applied to an injector of the fuel injection device. The present invention relates to a fuel pressure control method.

[0002]

2. Description of the Related Art Direct injection type 2 in which fuel is directly injected into a cylinder
BACKGROUND ART A fuel injection device used for a cycle internal combustion engine includes an injector mounted to inject fuel into a cylinder (combustion chamber) of the engine, a high-pressure fuel pump that supplies fuel to a fuel supply port of the injector, and an injector from the fuel pump. Pressure regulator for controlling the fuel pressure (fuel pressure) supplied to the engine to an adjusted value, an electronic control unit (ECU) for controlling the injector, a signal generator for providing engine rotation information, and a throttle valve opening And various sensors for detecting various control conditions such as the atmospheric pressure, the intake air temperature of the engine, etc., and supplying the detected conditions to the ECU.

[0003] The ECU has a CPU, and the number of revolutions of the engine calculated from the generation interval of the output signal of the signal generator,
A fuel injection time (fuel injection time) is calculated with respect to control conditions detected by various sensors, and a drive current is supplied to the injector so that the fuel is injected from the injector during the calculated fuel injection time. .

The ECU also controls an internal combustion engine ignition device and the like under various control conditions such as the number of revolutions of the internal combustion engine.

The injector has an injector body having a fuel supply port to which fuel is supplied from a fuel pump and a fuel injection port, a valve for opening and closing the fuel injection port of the injector body, and a solenoid for driving the valve. An electromagnetic fuel injection valve injects fuel by opening the valve while a predetermined drive current is applied from the ECU to the solenoid coil.

In the above-described fuel injection device, the amount of fuel supplied to the engine is determined by the product of the fuel pressure applied to the injector and the fuel injection time, but if both the fuel pressure and the fuel injection time are changed, Because control becomes complicated,
In general, control is performed so that the fuel pressure applied to the injector during the steady operation of the engine is maintained at a target value set in a range of 7 to 9 MPa, and the amount of fuel supplied to the engine is controlled by controlling the fuel injection time by the ECU. I am trying to do it.

The ECU also stops driving the injector to stop fuel injection when the stop command is given, stops the fuel pump, and further stops the operation of the ignition device for igniting the engine. To stop.

For a while after the engine is stopped, the fuel pressure applied to the injector is almost equal to the fuel pressure during steady operation. However, if the engine is left stopped for a long time, the fuel pressure applied to the injector is reduced. The fuel pressure gradually decreases and eventually converges to a pressure substantially equal to the atmospheric pressure.

[0009]

As described above, a direct injection type fuel injection system in which fuel is directly injected into a cylinder by a fuel injection device.
In a cycle internal combustion engine, the magnitude of the fuel pressure applied to the injector is significantly different between a state immediately after the engine is stopped and a state after a long time has elapsed after the engine is stopped. When starting the engine, the fuel injection time cannot be accurately calculated, and there is a problem that the startability of the engine deteriorates.

That is, when the fuel injection time at the time of starting the engine is calculated based on the fuel pressure immediately after the engine is stopped, the engine is started when a long time has elapsed after the engine was stopped. In such a case, it is inevitable that the fuel injection time at the time of starting becomes too short and the startability of the engine deteriorates.

In the case where the fuel injection time at the time of starting the engine is calculated based on the fuel pressure at the time when a long time has elapsed since the engine was stopped, the engine is restarted immediately after the engine is stopped. In such a case, the fuel injection time at the time of starting becomes too rich, and the startability of the engine is deteriorated. In some cases, the ignition plug is worn and it becomes difficult to start the engine.

[0012] It is an object of the present invention to provide a fuel injection system for both restarting the engine immediately after stopping the engine and starting the engine after leaving the engine stopped for a long time. Fuel injection system for a direct injection type two-stroke internal combustion engine capable of always controlling the engine so as to improve the startability of the engine, and the fuel pressure control of the fuel injection system It is to provide a method.

[0013]

A fuel pressure control method according to the present invention is a method for controlling a fuel pressure applied to an injector of a fuel injection device used in a direct injection type two-stroke internal combustion engine.
In the control method according to the present invention, when the internal combustion engine is stopped, the fuel pressure at stop is reduced to a value lower than a target value during steady operation.

At the time of steady operation of the internal combustion engine, control is performed so that the value of the fuel pressure becomes the target value at the time of steady operation, as in the conventional fuel pressure control method. The target value of the fuel pressure during steady operation may be a predetermined constant value, or may change stepwise or continuously according to a change in a predetermined control condition.

In a two-cycle in-cylinder direct injection engine, as the engine speed increases, the length of time during which fuel can be injected becomes shorter. Since it is necessary to inject a predetermined amount of fuel into the engine, in a low-speed region of the engine, the target value of the fuel pressure is set to a relatively low value, and the target value of the fuel pressure is increased as the rotation speed increases. The target value of the fuel pressure may be changed stepwise or continuously according to the engine speed.

That is, during steady-state operation, it is sufficient that the fuel pressure value at each instant can be specified in order to enable the calculation of the fuel injection time, and how the fuel pressure is controlled is arbitrary.

In the stop-time fuel pressure reduction control, it is preferable to reduce the fuel pressure to a value substantially equal to the convergence value of the fuel pressure when the internal combustion engine is left in a stop state for a sufficiently long time.

As described above, when the internal combustion engine is stopped, the stop-time fuel pressure reduction control for reducing the value of the fuel pressure to a value lower than the target value at the time of steady operation is performed. In both cases of restarting the engine and restarting the engine after leaving it in a stopped state for a long time, the fuel pressure applied to the injector at the time of starting can be made substantially the same, so that the engine By making the fuel injection amount at the time of starting almost always constant, it is possible to prevent the fuel injection amount from being excessive or insufficient at the time of starting, and to always improve the startability of the engine.

A fuel injection device used for a direct injection two-cycle internal combustion engine is an injector provided to inject fuel directly into a cylinder of the two-cycle internal combustion engine, and a high-pressure fuel pump for supplying fuel to the injector. A pressure regulator that controls the fuel pressure given to the injector from the fuel pump to an adjusted value, and a control unit that has an injector control unit that controls the timing of starting fuel injection from the injector and the fuel injection time. It is constituted by.

When the present invention is applied to such a direct injection type two-stroke engine, the pressure regulator
A control unit that is configured to control the fuel pressure adjustment value is used, and the control unit controls the pressure regulator so that the fuel pressure value becomes a target value during the steady operation during the steady operation of the internal combustion engine. In addition to the means, in the process of stopping the internal combustion engine, there is provided a stop-time fuel pressure reduction control means for controlling the pressure regulator so as to reduce the value of the fuel pressure applied to the injector to a value lower than the fuel pressure during steady operation of the internal combustion engine. Configuration.

[0021]

FIG. 1 shows an example of the construction of a fuel injection device for a direct injection two-cycle internal combustion engine according to the present invention. In FIG. 1, reference numeral 1 denotes a two-cycle internal combustion engine.
The illustrated internal combustion engine 1 includes a crankcase 100, a cylinder 102 connected to the crankcase, a piston 103 fitted in the cylinder 102, a crankshaft 104 supported by the crankcase 100, and a crankshaft 104. And a crank mechanism 105 connecting the piston 103 and the piston 103. The cylinder 102 has an intake port 106 and a scavenging port 107.
And an exhaust port (not shown). Scavenging port 10
Reference numeral 7 denotes a crankcase 100 through a scavenging passage (not shown).
The intake port 106 is connected to a throttle body 108
It is connected to the. A throttle valve 109 is attached to the throttle body 108. An ignition plug 2 and an injector 3 are attached to the cylinder 102, and a high voltage Vh for ignition is applied to the ignition plug 2 from an ignition coil 4.

The illustrated internal combustion engine is a two-cylinder internal combustion engine having two cylinders, and each cylinder has an ignition plug 2 and an injector 3.
And are attached.

A drive shaft of a high-pressure fuel pump 6 is connected to the crankshaft 104 via a speed reduction mechanism 5 such as a chain sprocket mechanism. At the inlet of the high-pressure fuel pump 6,
Fuel is supplied from a fuel tank 7 through a low-pressure fuel pump 8 and a filter 9. The low-pressure fuel pump 8 is an electric pump driven by a DC voltage obtained by rectifying the output of a magnet generator described later, and supplies the fuel in the fuel tank 7 to the high-pressure fuel pump 6 at a predetermined discharge pressure. I do. The high-pressure fuel pump 6 is a pump that is driven to rotate by the internal combustion engine 1. The pressure of the fuel discharged from the low-pressure fuel pump 8 is further increased and supplied to the injector 3 at a pressure of 7 to 9 MPa.

The injector 3 includes a valve body 3a having an injection port at the tip thereof, a valve for opening and closing the injection port, a spring for urging the valve to the closed position side, and a solenoid coil for driving the valve to the open position side. A fuel connector 3b provided at the rear end of the valve body 3a is connected to a discharge port of the high-pressure fuel pump 6 through a fuel supply pipe 10.

An electric connector 3c is also provided at the rear end of the valve body 3a, and a drive current is supplied from a controller described later to the solenoid coil of the injector 3 through the electric connector 3c.

The injector 3 opens a valve to start fuel injection when a drive current of a predetermined level or more is applied to its solenoid coil, and while the holding current of a predetermined level is applied to the solenoid coil, the injector opens. Open the valve to continue fuel injection. The amount of fuel injected from the injector 3 depends on the fuel pressure given to the injector 3 and
It is determined by the product of the fuel injection time (fuel injection time).

The low-pressure pressure regulator 1 passes through a pipe 11 through a pipe connecting the filter 9 connected to the discharge port of the low-pressure fuel pump 8 and the suction port of the high-pressure fuel pump 6.
2 are connected. Low pressure pressure regulator 12
When the pressure in the pipe 11 exceeds a set value, a part of the fuel in the pipe 11 is returned to the fuel tank 7 through the return pipe 13 so that the pressure of the fuel in the high-pressure fuel pump 6 is adjusted to a substantially constant adjustment value. Is controlled so as to be held.

A high-pressure pressure regulator 15 is connected to a discharge port of the high-pressure fuel pump 6 through a pipe 14. The high-pressure pressure regulator 15 transfers a part of the fuel in the pipe 14 to the return pipe 16 when the pressure in the pipe 14 (fuel pressure given to the injector 3) exceeds a set value.
Through the high pressure fuel pump 6
(The fuel pressure applied to the injector 3) is controlled to be maintained at an adjusted value adjusted to a certain value in the range of 7 to 9 MPa. The high-pressure fuel pump 15 can adjust the sectional area of the flow path of the fuel to be returned through the return pipe 16 by a solenoid, and supplies a control signal Vp given from an electronic control unit (ECU) described later to the solenoid. Thus, the return flow rate can be adjusted, and the adjustment value of the fuel pressure applied to the injector 3 can be appropriately adjusted.

The flywheel magnet rotor 20 is also attached to the crankshaft 104 of the internal combustion engine 1. The flywheel magnet rotor 20 includes a flywheel 21 formed of a ferromagnetic material such as iron into a substantially cup shape, and a magnet field formed by attaching a permanent magnet 22 to an inner periphery of a peripheral wall of the flywheel 21. A ring gear 23 having 60 teeth is attached to the outer periphery of the flywheel 21. A stator 25 is disposed inside the flywheel magnet rotor 20, and a well-known magnet generator 26 is provided by the magnet rotor 20 and the stator 25.
Is configured. The ring gear 23 is used for rotating a crankshaft of the internal combustion engine by engaging a pinion gear driven by a starting motor when starting the internal combustion engine.

The illustrated stator 25 is formed by winding a coil around each salient pole of a star-shaped annular armature core in which a number of salient poles are projected radially from the outer periphery of an annular yoke. I have.

Of the salient pole portions provided on the stator 25, 3
The salient poles are provided at an angular interval of 45 degrees, and coils W1 and W2 wound around two of the three salient poles are provided.
Are connected in series with their polarities matched to form a low-speed exciter coil, and the other coil W3 forms a high-speed exciter coil. The low-speed exciter coil is a coil with a large number of turns set so as to give a sufficiently high drive voltage to an internal combustion engine ignition device described later when the engine is at low speed, and the high-speed exciter coil is used for the ignition device when the engine is at high speed. It is a coil with a small number of turns set to give a high voltage.

The other seven salient pole portions provided on the stator 25 are provided at an angular interval of 30 degrees corresponding to the pole interval of a normal 12-pole iron core. An armature coil Wn for driving other electrical components is wound.

On the outer periphery of the peripheral wall of the flywheel 25,
A reluctor 27 formed of an arc-shaped projection is formed. A crank angle sensor 28 that detects the reluctor 27 and generates a pulse signal is provided outside the magnet rotor 20, and a ring gear 23.
And a gear sensor 29 that detects a tooth of the gear and generates a pulse signal.

The crank angle sensor 28 is a well-known generator that has an iron core having a magnetic pole portion facing the reluctor 27 at its tip, a pulsar coil wound around the iron core, and a permanent magnet magnetically coupled to the iron core. , Is mounted on a sensor mounting portion provided in an engine case or the like. This sensor 28
Outputs pulse signals Vs and Vs ′ having different polarities from the pulsar coil when detecting the leading edge of the reluctor 27 in the rotation direction and the trailing edge of the reluctor 27 in the rotation direction, respectively.

In the illustrated example, the rotation angle position of the crankshaft when the piston of the first cylinder of the internal combustion engine 1 reaches the top dead center (hereinafter, simply referred to as the top dead center position of the first cylinder) is one.
At the position advanced by 2 degrees, the crank angle sensor 28
7, the pulse signal V is detected by detecting the front edge of the rotation direction.
The position at which the crank angle sensor 28 is attached and the arc length of the reluctor 27 are set so as to generate s, and this pulse signal Vs is used as a reference pulse for determining the cylinder of the engine.

The gear sensor 29 has the same configuration as the crank angle sensor 28, and is fixed to a sensor mounting portion provided in an engine case or the like. The gear sensor 29 generates a pulse signal having a different polarity when detecting the leading edge of each tooth of the ring gear 23 in the rotating direction and detecting the trailing edge of each tooth in the rotating direction. Gear sensor 29
Among the pulses having different polarities generated when each of the teeth of the ring gear 23 is detected, a pulse of one polarity is used as a rotation detection pulse Vθ for detecting the rotation angle of the crankshaft of the engine. In the illustrated example, this rotation detection pulse is 6
This is a pulse generated at intervals of 60 degrees per revolution of the crankshaft. In the illustrated internal combustion engine, by counting the rotation detection pulse Vθ output from the gear sensor from the time when the crank angle sensor generates the reference pulse Vs, the reference for starting the measurement of the ignition position and the fuel injection start position of each cylinder is started. Detect the position.

The AC voltage Vac generated by the armature coil for driving the electrical components of the stator 25 of the magnet generator 26, the reference pulse Vs generated by the crank angle sensor 28, and the gear sensor 2
9 is input to the electronic control unit (ECU) 30.

The ECU 30 also has a throttle valve 1
An output signal St of the throttle opening sensor 31 for detecting the opening of the engine 09, an output signal Sa of the intake air temperature sensor 32 for detecting the intake air temperature of the engine, and a cooling water temperature sensor 33 for detecting the temperature of the cooling water of the engine. The output signal Sw and the output signal Sp of the atmospheric pressure sensor 34 for detecting the atmospheric pressure are input.

The ECU 30 is also connected with a stop switch 35 which is operated when the engine is stopped. When the stop switch is operated, a stop command signal S is sent to the ECU 30.
o is given.

FIG. 2 shows an example of the configuration of the ECU 30. This ECU includes a CPU 40 and a memory (ROM) 4 storing programs executed by the CPU and characteristic data.
1 and a capacitor discharge ignition circuit (CDI ignition circuit)
42, a drive circuit section 43, a power supply circuit 44, an oscillation circuit 45 for applying a clock pulse to the CPU, a reference pulse Vs generated by the crank angle sensor 28, and a gear sensor 29.
The waveform shaping circuit 46 shapes the rotation detection pulse Vθ generated by the throttle opening into a signal having a waveform recognizable by the CPU 40, and the throttle opening detection signal S generated by the throttle opening sensor 31.
t, a water temperature detection signal Sw generated by the cooling water temperature sensor 33
And an intake air temperature detection signal S generated by the intake air temperature sensor 32
a and the atmospheric pressure detection signal Sp generated by the atmospheric pressure sensor 34
And a stop command signal So generated by the stop switch 35 into various waveforms recognizable by the CPU and input to the CPU 40 by various sensor input circuits (interface circuits) 47.
A rotation speed detection timer for detecting the rotation speed of the engine, an ignition position control timer for measuring the calculated ignition position,
A first cylinder injection control timer for measuring an injection start position of a first cylinder, a second cylinder injection control timer for measuring an injection start position of a second cylinder, a rotation speed detection gear sensor counter, and ignition Position control gear sensor counter, first cylinder injection start position control gear sensor counter, and second cylinder injection start position control gear sensor counter (FIGS. 1 and 2)
Does not show a timer and a counter. ).

The CDI ignition circuit 42 includes an ignition capacitor provided on the primary side of the ignition coil 4 and the magnet generator 26.
A charging circuit for charging an ignition capacitor to one polarity using an exciter coil provided in the CPU as a power source;
A discharge switch provided to conduct when an ignition pulse Vi is given from 0 to discharge the charge of the ignition capacitor through the primary coil of the ignition coil 4. A high voltage for ignition is induced in the secondary coil of the coil 4. C
The DI ignition circuit 42 is provided for each cylinder,
When the ignition pulse Vi1 or Vi2 is given to the CDI ignition circuit for each cylinder from the above, a high voltage for ignition is induced in the secondary coil of the ignition coil 4 for each cylinder, and the ignition voltage for each cylinder is generated by the high voltage. Spark discharge occurs in the plug, and each cylinder is ignited.

In this type of ignition circuit, the ignition capacitor is connected to both the engine at low speed and at high speed.
Since it is necessary to charge to a high voltage of 00 [V] or more,
As an exciter coil used as a power supply for charging the ignition capacitor, a low-speed exciter coil having a large number of turns and outputting a high voltage Ve1 at a low speed and a high-speed exciter coil having a small number of turns and outputting a high voltage Ve2 at a high speed are provided. , The voltages Ve1, V output by both exciter coils
Of the e2, the higher voltage is used to charge the ignition capacitor. Since such an ignition circuit is well known, a detailed description thereof will be omitted.

The drive circuit 43 includes an injector drive circuit 43A for supplying a drive current Ij to the solenoid coil of the injector 3 in response to the injection signal Vj1 or Vj2 given from the CPU 40, and a low-pressure fuel pump 8 in response to a command from the CPU 40. And a high-pressure pressure regulator control drive circuit 43C that supplies a control signal Vp to a solenoid for adjusting the feedback flow rate of the high-pressure pressure regulator 15 in response to a command from the CPU 40. .

The power supply circuit 44 includes a rectifier for rectifying the AC voltage Vac output from the stator 25 of the magnet generator 26, and a voltage control circuit for controlling the output voltage of the rectifier so as to be kept below a certain value. The AC voltage Vac is converted into constant DC voltages Vcc1 and Vcc2, and these voltages are
The voltage is applied to the power supply terminal of the PU 40 and the power supply terminal of the drive circuit unit 43.

The power supply circuit 44 is connected to the DC voltages Vcc1 and Vcc.
cc2 may be configured to be obtained from a common armature coil of a magnet generator, or voltages Vcc1 and Vcc2 may be configured to be obtained from different armature coils. Further, the configuration may be such that a DC voltage for driving the injector 3 and a voltage for driving the low-pressure fuel pump 8 are obtained from the output of another armature coil.

The CPU 40 provided in the ECU 30 determines the time required for the gear sensor 29 to generate a predetermined number of rotation detection pulses by the rotation number detection timer (in this example,
Time required for the crankshaft of the engine to rotate 12 degrees) T
n is detected, and the rotation speed of the crankshaft of the engine is detected (calculated) from the time Tn. The detection of the rotation speed may be performed only once during one rotation of the engine, or may be performed a plurality of times per rotation. In the illustrated example, the first
The number of revolutions is detected before the ignition of the cylinder and before the ignition of the second cylinder.

The CPU 40 also determines the detected engine speed, the throttle opening detected by the throttle opening sensor 31, the cooling water temperature detected by the cooling water temperature sensor 33,
The operating state of the engine is predicted from the intake air temperature detected by the intake air temperature sensor 32 and the atmospheric pressure detected by the atmospheric pressure sensor 34 so that an appropriate amount of fuel is injected from the injector at a timing suitable for the operating state. The injection start position of the injector of each cylinder (the rotational angle position of the crankshaft that opens the injector valve) and the injection time (the time that the injector valve is open) are calculated, and the engine is ignited at a position appropriate for the operating state. Then, the ignition position of each cylinder is calculated.

The CPU 40 counts the rotation detection pulse V.theta. Generated by the gear sensor 29 from the time when the crank angle sensor 28 generates the reference pulse Vs, so that the measurement of the injection start position of the injector for each cylinder is started. Detection of a certain injection reference position and detection of the ignition reference position, which is the position where measurement of the ignition position of each cylinder is started, are performed.

Then, when the injection reference position of each cylinder is detected, measurement of the injection start position of the injector of each cylinder calculated by the CPU is started, and when the injection start position of the injector of each cylinder is detected. An injection signal is given to the injector drive circuit 43A so as to open the injector valve during the calculated injection time. As a result, a drive current is applied from the drive circuit 43A to the injector of each cylinder to cause fuel injection.

The CPU 40 also starts measuring the ignition position of each cylinder calculated when the ignition reference position of each cylinder is detected. When the calculated ignition position of each cylinder is detected, An ignition pulse Vi1 or Vi2 is given to the CDI ignition circuit for each cylinder to cause each cylinder to perform an ignition operation.

FIG. 4 shows a reference pulse Vs generated by the crank angle sensor 28 of the internal combustion engine, a rotation detection pulse Vθ generated by the gear sensor 29, and a CPU for the CDI ignition circuit for the first cylinder and for the second cylinder. For the first and second cylinders respectively given to the CDI ignition circuit
FIG. 4 is a timing chart showing, with respect to time t, 1, Vi2, and a first cylinder injection signal and a second cylinder injection signal provided by the CPU to injector drive circuits for the first cylinder and the second cylinder, respectively.

In FIG. 4, # 1 and # 2 denote the first and second cylinders of the internal combustion engine, respectively, and the signals or events denoted by # 1 and # 2 are those for the first cylinder and those for the first cylinder. It means a signal or event for the second cylinder. The BTDC 12 means that the rotation angle position is 12 degrees before the top dead center position of the engine, and the crank angle sensor 2
No. # 1 BTD attached to the reference pulse Vs output by the reference numeral 8
C12 means that the reference pulse Vs is generated at a position advanced by 12 degrees from the top dead center position of the first cylinder. That is, in the present specification, “BTDC” means that the rotation angle of the crankshaft is an angle measured on the advance side with respect to the top dead center position.

In FIG. 4B, n1, n2,.
Indicates the number of output pulses of the gear sensor when the counting of output pulses of the gear sensor 29 is started from the time when the crank angle sensor 28 generates the reference pulse Vs, and n1
(# 1), n2 (# 1),... Indicate the count value for the first cylinder, and n1 (# 2), n2 (# 2),.

Further, n1 (# 1) and n2 (# 1) are the first count value and the last count value of the rotation detection pulse Vθ when detecting the rotation speed prior to the ignition operation of the first cylinder, respectively. Counts the rotation detection pulse Vθ generated by the gear sensor from the time when the reference pulse Vs is detected by the counter, and counts the n1 (# 1) th rotation detection pulse and then counts the n2 (# 1) th rotation. The time Tn until the detection pulse is counted is measured by the rotation speed detection timer 1. The rotation speed of the crankshaft is calculated from the time Tn.

Similarly, n1 (# 2) and n2 (# 2) are the first count value and the last count value of the rotation detection pulse Vθ when detecting the rotation speed prior to the ignition operation of the second cylinder, respectively. The CPU measures the time Tn from the counting of the rotation detection pulse at the n1 (# 2) th count to the counting of the rotation detection pulse at the n2 (# 2) th by the timer 1, and from this time Tn Calculate the number of revolutions of the crankshaft.

As shown in the timing chart of FIG.
The rotation angle position of the crankshaft when the crank angle sensor 28 outputs the reference pulse Vs is defined as θb [BTDC], and the gear sensor 29 first generates the rotation detection pulse Vθ from the rotation angle position when the reference pulse Vs is generated. Assuming that the angle up to the rotation angle position at the time of rotation is θgo [deg], the rotation angle position θc [BTDC] of the crankshaft when the count value of the output pulse of the gear sensor reaches the nth count is given by the following equation. Can be

Θc = θb−θgo− (n−1) (360/60) [BTDC] (1) The n1th count value of the count value of the output pulse of the gear sensor after the crank angle sensor generates the reference pulse Vs ( θn1
N2-th count (θ from the rotation angle position of [BTDC])
When the time Tn required for the engine to rotate to n2 [the rotation angle position of [BTDC]) is detected, the engine speed N [rp]
m] can be obtained by the following equation.

N = ｛(Tn × 360) / (n2-n
1)｝ × 10 ⁻⁶ [rpm] (2) Also, as described above, it is necessary for the crankshaft to rotate from the position where the count value of the output pulse of the gear sensor becomes the n1th count to the position where the count value becomes the n2th count. When the detected time Tn can be detected, the change amount Δθc [deg] of the rotational angle position of the crankshaft when a certain time t [μsec] has elapsed can be obtained by the following equation.

Δθc = (t / tn) (n2−n1) (360/60) [deg] (3) In FIG. 4, n3 gives an ignition reference position at which measurement of the ignition position is started. N3 (# 1) is a count number of the rotation angle detection pulse, and n3 (# 1) is a rotation detection pulse that provides an ignition reference position for starting measurement of the ignition position of the first cylinder, and n3 (# 1) after the generation of the reference pulse Vs. N3 (# 2) is a rotation detection pulse that provides an ignition reference position for starting measurement of the ignition position of the second cylinder, and n3 (# 2) is n3 (# 2) after the generation of the reference pulse Vs.
(# 2) It means that it is the count pulse.

When the CPU detects the rotation detection pulse of the n3 (# 1) th count, the CPU 2 sets the ignition position control timer 2
A count value Ti for measuring the calculated ignition position is set to start counting, and the ignition position control timer 2
When the set value is counted, the CDI for the first cylinder is counted.
An ignition pulse Vi1 is applied to the ignition circuit to cause ignition of the first cylinder.

Similarly, when the CPU detects the rotation detection pulse of the n3 (# 2) th count, the CPU calculates a count value T for measuring the ignition position calculated by the ignition position control timer 2.
i is set to start counting, and when the ignition position control timer 2 counts the set value, an ignition pulse Vi2 is given to the CDI ignition circuit for the second cylinder to ignite the second cylinder.

In FIG. 4, n4 is the number of rotation angle detection pulses (output pulses of the gear sensor) that provide an injection reference position which is a position at which the injector starts measuring an injection start position at which fuel injection is started. Yes, n4
(# 1) is a pulse generated at the n4 (# 1) count after the generation of the reference pulse Vs, which is the rotation detection pulse that provides the injection reference position for starting the measurement of the injection start position of the injector of the first cylinder. Means n4 (# 2)
Means that the rotation detection pulse for providing the injection reference position for starting the measurement of the injection start position of the injector of the second cylinder is a pulse generated at the n4 (# 2) count after the generation of the reference pulse Vs. .

When the CPU detects the n4 (# 1) th rotation detection pulse, the CPU 3 counts the injection start position calculated by the timer 3 for controlling the injection start position for the first cylinder. Is set to start the counting, and a time width Tj1 corresponding to the injection time calculated by the injector drive circuit 43A when the count value set by the injection start position control timer 3 for the first cylinder is counted. The injection signal Vj1 for one cylinder is given to inject the fuel from the injector of the first cylinder.

When the CPU detects the rotation detection pulse of the n4 (# 2) th count, the CPU calculates the injection start position calculated by the injection start position control timer 4 for the second cylinder. T4 is set to start counting, and when the count value set by the injection start position control timer 4 for the second cylinder is counted, the injector drive circuit 43A
The injection signal Vj2 for the second cylinder having the time width Tj2 corresponding to the calculated injection time is given to inject the fuel from the injector of the second cylinder.

When stopping the engine, the stop switch 35
Sends a stop command to the ECU. When a stop command is given, the ECU stops the supply of the injection signal to the injector drive circuit 43A to stop the injection of fuel from the injectors of the first and second cylinders, and performs the CDI operation.
The supply of the ignition pulse to the ignition circuit 42 is stopped, and the engine is stopped by stopping the ignition operation.

The fuel pressure applied to the injectors 3 of each cylinder is adjusted by the high-pressure pressure regulator 15.
As described above, the ECU 30 includes the return flow rate adjusting means for changing the cross-sectional area of the flow path of the fuel which is driven by the solenoid and returned through the return pipe 16.
Is supplied to the solenoid to adjust the return flow rate, whereby the adjustment value of the fuel pressure applied to the injector 3 can be appropriately adjusted.

In the present invention, during steady-state operation of the internal combustion engine, C is set so that the target value of the fuel pressure adjusted by the high-pressure pressure regulator 15 becomes equal to the target value during steady-state operation.
When the control signal Vp is supplied from the PU 40 to the solenoid of the high-pressure pressure regulator 15 to stop the internal combustion engine, the high-pressure pressure regulator is controlled so as to reduce the value of the fuel pressure applied to the injector 3 to a value lower than the target value during steady-state operation. The control signal Vp is supplied to the 15 solenoids to perform the stop-time fuel pressure reduction control.

In this stop-time fuel pressure reduction control, it is preferable to reduce the fuel pressure applied to the injector to a convergence value (substantially equal to the atmospheric pressure) of the fuel pressure when the engine has been left idle for a long time. The injection time at engine start is
The calculation is performed based on the fuel pressure reduced by the stop fuel pressure reduction control.

As described above, when the internal combustion engine is stopped,
If the stop-time fuel pressure reduction control that lowers the fuel pressure value to a value lower than the target value during steady-state operation is performed, the engine may be restarted immediately after the engine is stopped, or the engine may be stopped for a long time. In any case where the engine is restarted after being left unattended, the fuel pressure applied to the injector 3 at the time of starting can be made substantially the same. It is possible to prevent the injection quantity from being excessive or insufficient, and to always improve the startability of the engine.

If a fuel pressure sensor for detecting the fuel pressure applied to the injector is provided and the fuel injection time is calculated according to the fuel pressure detected by the fuel pressure sensor,
Although the above problem can be solved, the provision of a fuel pressure sensor inevitably increases the number of parts and increases the cost.In addition, when calculating the fuel injection time, in addition to various control conditions, Since it is necessary to consider the fuel pressure, it is unavoidable that it takes time to calculate the fuel injection time.

FIG. 6 is a flowchart showing an example of an algorithm of a program executed by the ECU of the internal combustion engine.
To FIG.

In these flowcharts, a timer 1 is a rotation speed detection timer for measuring a time period during which a gear sensor generates a predetermined number of rotation detection pulses, and a timer 2 is calculated from the ignition reference position of each cylinder. The ignition position control timer measures the time required for the crankshaft to rotate to the ignition position.

The timer 3 is an injection control timer for the first cylinder which measures the time required for the crankshaft to rotate from the injection reference position of the first cylinder to the injection start position of the injector for the first cylinder. The timer 4 is an injection control timer for the second cylinder that measures the time required for the crankshaft to rotate from the injection reference position of the second cylinder to the injection start position of the injector for the second cylinder.

Further, the counter 1 counts the number of rotation detection pulses generated by the gear sensor in order to obtain a specific rotation detection pulse (the rotation detection pulse from the n1th count to the n2th count) used for detecting the number of rotations. The counter 2 is an ignition position control gear sensor counter that counts output pulses of the gear sensor 29 in order to obtain a rotation detection pulse that provides an ignition reference position for starting measurement of the ignition position. The counter 3 counts the output pulse of the gear sensor 29 in order to obtain an n4 (# 1) -th rotation detection pulse which gives an injection reference position at which the measurement of the injection start position of the injector of the first cylinder is started. Counter 4 is a gear sensor counter for controlling the injection start position of the second cylinder, and the counter 4 is for obtaining the rotation detection pulse at the n4 (# 2) th count which gives the injection reference position at which the measurement of the injection start position of the injector of the second cylinder is started. And a gear sensor counter for controlling the injection start position for the second cylinder for counting the output pulses of the gear sensor 29.

FIG. 6 shows a main routine of a program executed by the CPU, and FIG. 7 shows a crank angle sensor interrupt routine executed when the crank angle sensor 28 generates the reference pulse Vs. FIG. 8 shows an interrupt routine executed when the rotational speed detection counter 1 has counted n1 (# 2), n2 (# 2), n1 (# 1) or n2 (# 1). An interrupt routine executed when the ignition position control gear sensor counter 2 counts n3 (# 2) or n3 (# 1) is shown. Further, FIG.
Shows an interrupt routine executed when the ignition position control timer 2 measures the ignition position.

FIG. 11 shows an interrupt routine executed when the first cylinder injection start position control gear sensor counter 3 measures the injection start position of the first cylinder. FIG. 12 shows an injection control timer for the first cylinder. Reference numeral 3 denotes an interrupt routine executed when the injection signal of the first cylinder is generated and when the generation of the injection signal of the first cylinder is stopped.

FIG. 13 shows an interrupt routine executed when the second cylinder injection start position control gear sensor counter 4 measures the injection start position of the injector of the second cylinder, and FIG. 14 shows the interrupt routine for the second cylinder. An interrupt routine executed when the injection control timer 4 generates an injection signal for the second cylinder and stops generating the injection signal for the second cylinder is shown.

In the main routine of FIG.
After the power supply is established, first, the initial setting of each unit is performed, and then the interruption is permitted. Then, according to the task schedule, task 0, task 1, task 2, task 3A, and task 3B are performed.
Are sequentially executed at a predetermined timing.

In task 0, the throttle opening is detected from the output of the throttle opening sensor, and the engine speed is calculated from the time measured by the timer 1. Further, the state of the stop switch 35 is detected, and when a stop command is given, the number of revolutions at which the engine is misfired is determined.

In task 1, the detected values of the cooling water temperature, the intake air temperature, and the atmospheric pressure are read from the respective sensors, and the ignition position in a steady state is calculated to determine the ignition position.
Also, the count value n1 (# 1) to be counted by the counter 1,
n2 (# 1), n1 (# 2), n2 (# 2), and count values n3 (# 1) and n3 to be counted by the counter 2
(# 2) is determined. The ignition position in the steady state is calculated, for example, by using an ignition position calculation map that gives a relationship between the rotation speed and the ignition position, the ignition position at each rotation speed is calculated by an interpolation method. The actual ignition position is determined by multiplying a correction value Kw 'for the cooling water temperature described later. The ignition position of each cylinder is calculated in the form of the time required for the engine to rotate from the ignition reference position for each cylinder to the ignition position (this time is referred to as ignition position measurement time).

In the task 2, the injection time correction value Kw for the cooling water temperature, the injection time correction value Ka for the intake air temperature, and the injection time correction value Kp for the atmospheric pressure are set.
And the steady-state injection time determined by the rotation speed and the throttle opening, multiplying the steady-state injection time by the correction values Kw, Ka, and Kp, and adding the start-up increasing injection time (zero except during start-up). To calculate the actual injection time. The constant injection time is calculated by, for example, an interpolation method using a three-dimensional map that gives a relationship among the engine speed, the throttle valve opening, and the injection time.

In task 3A, it is determined whether or not to stop the engine, the ignition position at the time of starting the engine is calculated, the start-up increasing injection time for increasing the injection amount at the start is calculated, and the cooling water is calculated. A correction value Kw 'of the ignition position with respect to the temperature is calculated.

In task 3B, the count values n4 (# 1) and n4 of the counter 4 for calculating the injection start position and obtaining the injection reference position at which the measurement of the injection start position is started.
Determination of (# 2), calculation of the target value of the fuel pressure adjusted by the high-pressure pressure regulator 15, and output of the control signal Vp necessary to obtain the calculated target value of the fuel pressure (fuel pressure control)
And do. The target value of the fuel pressure is determined according to the operating state of the engine, and when it is determined in task 3A that the engine is to be stopped, the target value of the fuel pressure is set to a value substantially equal to the atmospheric pressure.
In the process of controlling the fuel pressure in this manner, when the internal combustion engine is stopped, when the pressure regulator 3 is controlled so as to reduce the value of the fuel pressure applied to the injector to a value lower than the fuel pressure during steady operation of the internal combustion engine, Fuel pressure reduction control means is realized.

In this example, the interrupt routine shown in FIGS. 7 to 14 is executed as follows.

When the crank angle sensor 28 generates the reference pulse Vs, the main routine of FIG. 6 is interrupted, and the interrupt routine of FIG. 7 is executed. In the interrupt routine of FIG. 7, the pulse count value n1 (# 1) stored in the memory 41 is determined according to the operating state of the engine at that time.
n1 (# 2), n2 (# 1), n2 (# 2), n3 (#
The values of 1) and n3 (# 2) are read, and the calculated ignition position is read. Next, n1 (# 2) is set in the counter 1 and the process returns to the main routine.

The value n1 set by the count value of the counter 1
When (# 2) is reached, the main routine is interrupted and the interrupt routine shown in FIG. 8 is executed. In the interrupt routine of FIG. 8, first, in step 1, it is determined whether the count value counted by the counter 1 is n1 or n2. When the interrupt routine of FIG. 8 is first executed after the generation of the reference pulse Vs, since the count value of the counter 1 is n1, it is determined in step 2 whether n1 is n1 (# 1) or n1. (# 2) is determined. When the interrupt routine shown in FIG. 8 is first executed after the generation of the reference pulse Vs, the count value of the counter 1 is n1 (# 2). The counter 1 is set, and steps 4 and 5 are executed to store the measured value of the rotation speed detection timer 1 in the RAM.

When the count value of the counter 1 reaches n2 (# 2), an interrupt is generated again and the interrupt routine shown in FIG. 8 is executed. At this time, the count value of the counter 1 is n2 (# 2)
Therefore, the process proceeds to step 6 where n2 is n2 (#
It is determined whether it is 1) or n2 (# 2). Since the current count value of the counter 1 is n2 (# 2), the process proceeds to step 7 and sets the count value n1 (# 1) of the rotation detection pulse in the second detection of the rotation speed in the counter 1. Then, in step 8, a count value n3 (# 2) for giving the ignition reference position of the second cylinder is set in the ignition position control gear sensor counter 2. Next, at step 9, the measured value of the rotation speed detection timer 1 is read, and at step 10
Then, the difference Tn between the measured value of the timer 1 read this time and the measured value of the timer 1 previously read and stored in the RAM.
Is calculated. Next, in step 11, the time required for the engine to rotate from the ignition reference position to the ignition position is calculated, and R
Store it in the AM and return to the main routine.

When the count value of the counter 2 reaches n3 (# 2), an interrupt occurs (at the ignition reference position for the second cylinder), and the interrupt routine shown in FIG. 9 is executed. In this interrupt routine, first, it is determined whether the count value counted this time is for the first cylinder or for the second cylinder. This time, since the count value n3 counted by the counter 2 is for the second cylinder,
Next, the ignition position measurement time T already calculated by the ignition position control timer from the reference position for the second cylinder.
i2 is set in the ignition position control timer 2 and the process returns to the main routine.

Next, when the measured value of the timer 2 reaches the ignition position measuring time Ti2 of the second cylinder, the interrupt routine of FIG. 10 is executed. In this interrupt routine, step 1
It is determined whether the current ignition is the ignition of the first cylinder or the ignition of the second cylinder. Since the current ignition is the ignition of the second cylinder, the process proceeds to step 2 to determine whether or not to perform the misfire control. If the misfire control is not to be performed, the ignition pulse of the second cylinder is set to the second pulse in step 3. It is supplied to the CDI ignition circuit for the cylinder to cause the ignition of the second cylinder. Next, in step 4, the count value n4 (# 1) of the rotation detection pulse for providing the injection reference position of the first cylinder is set in the counter 3,
In step 5, the time (injection start position measurement time) T3 from the injection reference position to the injection start position is calculated and stored in the RAM, and the process returns to the main routine.

If a stop command is given by the stop switch 35 and it is determined in step 2 that misfire control should be performed, the process proceeds to step 4 without performing step 3 (output of an ignition pulse).

When the count value of the counter 3 reaches n4 (# 1), the interruption routine of FIG. 11 is executed, and the time for measuring the injection start position of the first cylinder is set in the injection control timer 3 of the first cylinder. .

When the measured value of the timer 3 becomes equal to the measured time of the injection start position of the first cylinder, the interruption shown in FIG. 12 is executed. In this interrupt, first, it is determined in step 1 whether the timing of this interrupt is the start or end of the injection, and if it is the start of the injection, in step 2, the energization to the solenoid coil of the injector of the first cylinder is started. Next, in step 3, the already calculated injection time is set in the injection time timer for the first cylinder, and the process returns to the main routine.

When the value measured by the timer 3 becomes equal to the injection time, the interrupt shown in FIG. 12 is generated again. Since the timing of this interruption is the timing indicating the end of the injection, the process proceeds from step 1 to step 4 to stop energizing the injector of the first cylinder.

Next, when the count value of the counter 1 becomes n1 (# 2), the interrupt shown in FIG. 8 is generated. In this interrupt, the process proceeds from step 2 to step 12, and the count value n2 (# 1) of the rotation detection pulse for performing the second counting of the number of rotations is set in the counter 1. Next, steps 4 and 5 are executed to store the measured value of the rotation speed detection timer 1 in the RAM.

When the count value of the counter 1 reaches n2 (# 1), the interrupt shown in FIG. 8 occurs again. In this interrupt,
Proceeding to step 6, it is determined whether n2 is n2 (# 1) or n2 (# 2). This time counter 1
Is n2 (# 1), and then step 1
The count value n1 (# 2) of the rotation detection pulse at the time of performing the first rotation number detection at step 3 is set in the counter 1, and in step 14, the count value n3 ( # 1) is set in the ignition position control gear sensor counter 2. Next, in step 9, the measured value of the rotation speed detecting timer 1 is read, and in step 10, the difference Tn between the currently read measured value of the timer 1 and the previously read measured value of the timer 1 and stored in the RAM is calculated. I do. Next, at step 11, the time required for the engine to rotate from the ignition reference position to the ignition position is calculated and stored in the RAM, and the process returns to the main routine.

When the count value of the counter 2 reaches n3 (# 1), an interrupt occurs (at the ignition reference position for the first cylinder), and the interrupt routine of FIG. 9 is executed. In this interrupt routine, first, it is determined whether the count value counted this time is for the first cylinder or for the second cylinder. This time, since the count value n3 counted by the counter 2 is for the first cylinder,
Next, the ignition position measurement time T for the first cylinder already calculated from the first cylinder reference position by the ignition position control timer.
i1 is set in the ignition position control timer 2 and the process returns to the main routine.

Next, when the measured value of the timer 2 reaches the ignition position measuring time Ti1 of the first cylinder, the interrupt routine of FIG. 10 is executed. In this interrupt routine, step 1
It is determined whether the current ignition is the ignition of the first cylinder or the ignition of the second cylinder. Since the current ignition is the ignition of the first cylinder, the process proceeds to step 6 to determine whether or not the misfire control should be performed. When the misfire control is not to be performed, the ignition pulse of the first cylinder is set to the first cylinder in step 7. It is supplied to a CDI ignition circuit for a cylinder to cause the first cylinder to ignite. Next, at step 8, the count value n4 (# 2) of the rotation detection pulse for providing the injection reference position of the second cylinder is set to the counter 4.
In step 5, the time (injection start position measurement time) T3 from the injection reference position to the injection start position is calculated and stored in the RAM, and the process returns to the main routine.

If a stop command is given by the stop switch 35 and it is determined in step 6 that misfire control should be performed, the process proceeds to step 8 without performing step 7 (output of an ignition pulse).

When the count value of the counter 4 reaches n4 (# 2), the interruption routine of FIG. 13 is executed, and the time for measuring the injection start position of the second cylinder is set in the injection control timer 4 of the second cylinder. .

When the measured value of the timer 4 becomes equal to the injection start position measurement time of the second cylinder, the interruption shown in FIG. 14 is executed. In this interrupt, first, it is determined in step 1 whether the timing of this interrupt is the start or end of injection, and if it is the start of injection, in step 2, the energization to the solenoid coil of the injector of the second cylinder is started. Next, at step 3, the already calculated injection time is set in the injection time timer for the second cylinder, and the process returns to the main routine.

When the value measured by the timer 4 becomes equal to the injection time, the interrupt shown in FIG. 14 is generated again. Since the timing of this interruption is the timing indicating the end of the injection, the process proceeds from step 1 to step 4 to stop energizing the injector of the second cylinder.

The above-described series of operations is repeated to operate the internal combustion engine. In the above example, the injector 3, the low-pressure fuel pump 8, the low-pressure pressure regulator 12, the high-pressure fuel pump 6, and the high-pressure pressure regulator 15
And the control unit 30 constitute a fuel injection device.

In the above example, the power supply voltage is supplied to the power supply circuit 44 by the output of the magnet generator. However, as shown in FIG. 3, even when the power supply voltage is supplied from the battery 50 to the power supply circuit in the ECU. Needless to say, the present invention can be applied. Although not shown in FIG.
Is charged by the output of the magnet generator 26 through the charging circuit.

[0104]

As described above, according to the present invention, when the internal combustion engine is stopped, the stop-time fuel pressure reduction control for reducing the fuel pressure value to a value lower than the target value in the steady operation is performed. Therefore, in both cases of restarting the engine immediately after stopping the engine and restarting the engine after leaving it in a stopped state for a long time, the fuel pressure applied to the injector at startup is almost the same. Can be. Therefore, there is an advantage that the fuel injection amount at the time of starting the engine is always substantially constant, and it is possible to prevent the fuel injection amount from being excessive or insufficient at the time of starting, and to always improve the startability of the engine.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a configuration example of a fuel injection device for a direct injection two-stroke internal combustion engine according to the present invention.

FIG. 2 is a configuration diagram showing a configuration example of an ECU used in the device of FIG. 1;

FIG. 3 is a configuration diagram showing another configuration example of the fuel injection device for a direct injection two-stroke internal combustion engine according to the present invention.

FIG. 4 is a timing chart showing the operation of the fuel injection device of FIG.

FIG. 5 is a timing chart for explaining a method of calculating a rotation speed and the like in the fuel injection device according to the present invention.

FIG. 6 is a flowchart showing an algorithm of a main routine of a program executed by a CPU provided in an ECU of the fuel injection device according to the present invention.

FIG. 7 is a flowchart showing an algorithm of a crank angle sensor interrupt routine executed when the crank angle sensor generates the reference pulse Vs in the program executed by the CPU provided in the ECU of the fuel injection device according to the present invention.

FIG. 8 is a flowchart illustrating an algorithm of an interrupt routine executed when a rotation speed detection counter counts a predetermined rotation detection pulse.

FIG. 9 is a flowchart showing an algorithm of an interrupt routine executed when an ignition position control gear sensor counter of the ECU provided in the apparatus of FIG. 1 has counted a predetermined rotation detection pulse.

10 is a flowchart illustrating an algorithm of an interrupt routine executed when an ignition position control timer of an ECU provided in the apparatus of FIG. 1 measures an ignition position.

11 is a flowchart showing an algorithm of an interrupt routine executed when a first cylinder injection start position control gear sensor counter of the ECU provided in the apparatus of FIG. 1 measures an injection start position of the first cylinder. is there.

12 is an interrupt executed when a first cylinder injection control timer of an ECU provided in the apparatus of FIG. 1 generates an injection signal of the first cylinder and stops generating an injection signal of the first cylinder. 9 is a flowchart illustrating a routine algorithm.

13 shows an algorithm of an interrupt routine executed when a gear sensor counter for controlling the injection start position for the second cylinder of the ECU provided in the apparatus shown in FIG. 1 measures the injection start position of the injector of the second cylinder. FIG.

14 is executed when an injection control timer for a second cylinder of the ECU provided in the apparatus of FIG. 1 generates an injection signal for the second cylinder and stops generating an injection signal for the second cylinder, respectively. 9 is a flowchart showing an algorithm of an interrupt routine performed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 2 cycle internal combustion engine, 2 ... Spark plug, 3 ... Injector, 4 ... Ignition coil, 6 ... High pressure fuel pump, 8 ... Low pressure fuel pump, 12 ... Low pressure pressure regulator, 1
5 ... High pressure regulator, 26 ... Magnet generator,
30 ... ECU, 40 ... CPU.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tsuneaki Endo 3744 Ooka, Numazu-shi, Shizuoka Domestic Electric Co., Ltd. Reference) 3G066 AA02 AA08 AD02 CA01U CB15 CC01 CD03 CE22 DA01 DA04 DB02 DC09 DC14 DC18 3G301 HA03 HA04 KA28 MA11 MA18 NE06 PA10Z PA11Z PB08A PE01Z PE04Z PE08Z PE09A

Claims (4)

[Claims] 1. A fuel pressure control method for controlling a fuel pressure applied to an injector of a fuel injection device used in a direct injection two-stroke internal combustion engine, wherein when the internal combustion engine is stopped, the value of the fuel pressure is controlled by the internal combustion engine. A fuel pressure control method for an in-cylinder direct injection two-cycle internal combustion engine fuel injection device, comprising performing stop-time fuel pressure reduction control to reduce the fuel pressure to a value lower than a target value during steady operation. 2. The stop-time fuel pressure reduction control according to claim 1, wherein the fuel pressure is reduced to a value substantially equal to a convergence value of the fuel pressure when the internal combustion engine is left in a stop state for a sufficiently long time. The fuel pressure control method for a fuel injection device for a direct injection two-cycle internal combustion engine according to claim 1. 3. An injector provided to inject fuel directly into a cylinder, a high-pressure fuel pump for supplying fuel to the injector, and control to maintain a fuel pressure applied from the fuel pump to the injector at an adjusted value. A pressure regulator, and a control unit having an injector control means for controlling fuel injection time and fuel injection time from the injector. The pressure regulator is configured to control an adjustment value of the fuel pressure, and the control unit determines a value of a fuel pressure applied to the injector when the internal combustion engine is stopped, at a fuel pressure during a steady operation of the internal combustion engine. Pressure regulator so as to reduce it to a lower value than Cylinder direct 噴形 2-cycle internal combustion engine fuel injection apparatus characterized by comprising a stop fuel pressure reduction control means Gosuru. 4. The stop-time fuel pressure reduction control means reduces the fuel pressure to a value substantially equal to a convergence value of the fuel pressure when the internal combustion engine is left in a stop state for a sufficiently long time. The fuel injection device for a direct injection two-cycle internal combustion engine according to claim 3.