JPH0315655A - Fuel injection device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve startability by feeding the compressed air from a combustion chamber to a compressed air passage when pressure in the combustion chamber reaches or exceeds the predetermined value at the time of an engine start in the system wherein fuel is jetted with the compressed air. CONSTITUTION:An air blast valve 20 so arranged in a cylinder head 3 as to expose the nozzle outlet 24 thereof in a combustion chamber 4 has a needle 23 inserted in a needle insertion hole 22 formed in a housing 21, and the needle 23 is actuated with a movable core 28 shifted on the excitation of a solenoid 30 against the force of a spring 27. Also, a compressed air passage 33 is connected to a nozzle chamber 32 formed in the housing 21 and the injection port 37 of a fuel injection valve 36 is positioned in the nozzle chamber 32. ln a fuel injection device as aforementioned, each of valves 20 and 36 is so controlled that fuel supply to the compressed air passage 33 is stopped at the time of an engine start, and the compressed air is supplied from the combustion chamber 4 to the compressed air passage 33 when pressure in the combustion chamber 4 reaches or exceeds the predetermined value.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a combustion injection device for an internal combustion engine.

[Conventional technology]

An internal combustion engine equipped with an air blast valve that blows out fuel using compressed air is known (Japanese Patent Application Laid-Open No. 1371-1989).
(See Publication No. 12). In this air blast valve, a metering chamber formed within the air blast valve is filled with liquid fuel, and the liquid fuel is forced out of the metering chamber by compressed air and ejected together with air.

[Problem to be solved by the invention]

By the way, when such an air blast valve is used and an attempt is made to obtain compressed air using an engine-driven air compressor, it takes time to increase the pressure of the air when the engine is started. For this reason, when starting the engine, compressed air whose pressure has been sufficiently increased cannot be obtained and fuel cannot be injected from the air blast valve, resulting in a problem that the starting time becomes longer.

[Means to solve the problem]

In order to solve the above problems, according to the present invention, a nozzle opening is formed at the tip of the compressed air passage facing into the combustion chamber, and an on-off valve for electromagnetically opening and closing the nozzle opening is disposed at the nozzle opening. In a combustion injection device that injects fuel supplied into an air passage into a combustion chamber from a nozzle port using compressed air supplied into the compressed air passage from a compressed air supply source driven by the engine, when the engine starts When the fuel supply to the compressed air passage is stopped and the pressure inside the combustion chamber exceeds a predetermined pressure, the on-off valve is opened to send the compressed air inside the combustion chamber into the compressed air passage. ing.

[For production]

According to the above-described structure, the present invention stops the supply of fuel into the compressed air passage when starting the engine, and opens the on-off valve when the pressure inside the combustion chamber exceeds a predetermined pressure. of compressed air is sent into the compressed air passage.

〔Example〕

First, a first embodiment will be described. 2 and 3, 1 is a cylinder block, 2 is a piston, 3 is a cylinder head, 4 is a combustion chamber, 5 is a pair of intake valves, 6 is an intake boat, and 7 is a pair of exhaust valves. , 8 indicates an exhaust port, and 9 indicates an ignition plug. A mask wall 10 is formed on the inner wall surface of the cylinder head 3 to close an opening between the peripheral edge of the intake valve 5 on the exhaust valve 7 side and the valve seat during the full opening period of the intake valve 5. Therefore, when the intake valve 5 opens, fresh air flows into the combustion chamber 4 from the side opposite to the exhaust valve 7 as shown by arrow A. Cylinder head 3 located between a pair of intake valves 5
An air blast valve 20 is arranged on the inner wall surface of.

FIG. 4 shows a partially sectional side view of the air blast valve 20.

Referring to FIG. 4, a straightly extending twenty-one dollar insertion hole 22 is formed in the housing 2l of the air blast valve 20.
A 21 dollar 23 having a smaller diameter is inserted. A nozzle nozzle 24 is formed at one end of the twenty-one dollar insertion hole 22, and this nozzle nozzle 24 is controlled to open and close by a valve portion 25 formed at the tip of the twenty-one dollar 23. This nozzle rod 24 is arranged within the combustion chamber 4. Further, a spring retainer 26 is fixed to the twenty-one dollar 23, and a compression spring 27 is inserted between the spring retainer 26 and the nozzing 21. Due to the spring force of this compression spring 27, the nozzle throat 24 is normally closed by the valve portion 25 of the twenty-one dollar valve 23. A movable core 28 is connected to the compression spring 2 at the end of the second dollar 23 opposite to the valve part 25.
A solenoid 30 and a stator 31 for attracting the movable core 28 are arranged in the nozzing 21 so that the solenoid 30 and the stator 31 are always in contact with each other by the spring force of the movable core 28 . When the solenoid 30 is energized, the movable core 28 moves toward the stator 31, and as a result, the second dollar 23 moves in the direction of the nozzle row 24 against the spring force of the compression spring 27, so that the nozzle row 24 is opened. .

On the other hand, inside the housing 21 is a cylindrical nozzle chamber 32.
is formed. One end 32a of the nozzle chamber 32 is communicated with the compressed air inflow passage 33, and the other end 32a of the nozzle chamber 32 is connected to the compressed air inflow passage 33.
b is connected to the secondary drain insertion hole 2 via the compressed air outflow passage 35.
2. A nozzle 37 of the fuel injection valve 36 is disposed within the nozzle chamber 32, and the nozzle 37 is located between one end 32a and the other end 32b within the nozzle chamber 32. As shown in FIG. 4, the compressed air outlet passage 35 extends straight. The nozzle 37 is arranged on the axis of the compressed air outflow passage 35, and the nozzle 37 is connected to the compressed air outflow passage 3.
Fuel with a small spread angle is supplied along the axis 5.

The compressed air outflow passage 35 extends obliquely to the twenty-one dollar insertion hole 22 in the direction of the nozzle rod 24, and forms an angle of 20 to 45 degrees with respect to the twenty-one dollar insertion hole 22. connected diagonally.

FIG. 1 shows the overall configuration of this embodiment. Referring to FIG. 1, 40 is an intake manifold, 41 is a surge tank, 42 is an air cleaner, and 43 is an air supply pipe connecting the surge tank 41 and the air cleaner 42, respectively. In the middle of the air supply pipe 43, air flow meters 4 are installed sequentially from the upstream side.
4, a throttle valve 45 and a mechanical supercharger 46 are provided. A conduit 47 is branched from the air supply pipe 43 between the air cleaner 42 and the air flow meter 44, and this conduit 47 is
It is connected to the intake port 48H of the air compressor 48. On the other hand, a discharge port 48b of the air compressor 48 is connected to the compressed air inflow passage 33. This air compressor 48
is driven by the engine and supplies compressed air to the air blast valve 20.

A pressure regulator 49 is provided in the middle of the compressed air inflow passage 33, and the pressure regulator 49 is connected to the conduit 47 via a return pipe 50.
to the air supply pipe 43 between the opening and the air flow meter 44 . When the compressed air pressure in the compressed air inflow passage 33 exceeds a predetermined pressure, the pressure regulator 49 releases compressed air through the return pipe 50, and adjusts the compressed air pressure in the compressed air inflow passage 33 to a predetermined pressure, e.g. Gauge pressure is 3kg/cn! Adjust to

The solenoid 30 of the air blast valve 20 and the fuel injection valve 36 are connected to an electronic control unit 60 and controlled by an output signal of the electronic control unit 60. The electronic control unit 60 is composed of a digital computer, and includes a ROM (read-on memory) 62 and a RAM (random access memory) 63 interconnected by a bidirectional bus 61.
, CPU (microprocessor) 64, input port 6
5 and an output boat 66.

The air flow meter 44 generates an output voltage proportional to the amount of intake air, and this output voltage is input to the input port 65 via the AD converter 67. In the compressed air inflow passage 33 near the air blast valve 20, there is a pressure sensor 51 that generates an output voltage proportional to the compressed air pressure in the compressed air inflow passage 33.
is attached, and the output voltage of this pressure sensor 51 is AD
It is input to input port 65 via converter 68 . Further, a water temperature sensor 52 that generates an output voltage proportional to the engine cooling water temperature is attached to the cylinder block 1, and the output voltage of this water temperature sensor 52 is inputted to an input port 65 via an AD converter 69. Further, the input port 65 includes a crank angle sensor 53 that generates an output pulse representing the engine rotation speed, and a crank reference position sensor 54 that generates an output pulse at a predetermined crank angle position for each crank rotation.
, and a starter switch 55 are connected.

On the other hand, the output port 66 is connected to the air blast valve solenoid 30 and the fuel injection valve 36 via corresponding drive circuits 70, 72.

Referring again to FIG. 4, the 21 dollar insertion hole 22 and the nozzle chamber 3 are
2 and the compressed air outflow passage 35 are the compressed air inflow passage 33
The air compressor 48 (see FIG. 1) is connected to the air compressor 48 (see FIG. 1). Therefore, these 21 dollar insertion holes 22, nozzle chamber 3
2 and the compressed air outflow passage 35 are filled with compressed air. Fuel is supplied into this compressed air from the nozzle 37 along the axis of the compressed air outflow passage 35 . As shown in FIG.
Most of the supplied fuel is connected to the valve part 2 at an angle.
It reaches into the 21 dollar insertion hole 22 around the 21 dollar 23 near 5. At this time, some of the fuel adheres to the inner wall surface of the compressed air outflow passage 35 and the inner wall surface of the nozzle chamber 32. Next, when the solenoid 30 is energized, the needle 23 opens the nozzle rod 24. At this time, since the supplied fuel is gathered near the valve part 25, as soon as the 21 dollar 23 opens the nozzle nozzle 24, both fuel and compressed air are sent from the nozzle nozzle 24 to the combustion chamber 4.
Squirt inside. Further, when the needle 23 opens the nozzle row 24, compressed air flows into the nozzle chamber 32 from the compressed air inflow passage 33, and then goes to the nozzle row 24 via the compressed air outflow passage 35. The fuel adhering to the inner wall surface of the nozzle chamber 32 and the inner wall surface of the nozzle chamber 32 is carried away by the compressed air flow and is ejected from the nozzle row 24. Therefore, as soon as the 21 dollar valve 23 opens, all of the injected fuel is jetted out from the nozzle row 24, and then only compressed air is jetted out from the nozzle row 24 when the injection of all the supplied fuel is completed. Then solenoid 3
0 is deenergized and the 21 dollar 23 closes the nozzle rod 24. Therefore, just before the valve 23 is closed, only air is blown out from the nozzle 24.

Next, the operation of this embodiment will be explained with reference to FIG. In order to start the engine, the starter switch 55 is turned on at point (a).
When turned on, the air compressor 48 is driven by the engine, and the compressed air pressure P in the compressed air inlet passage 33 is gradually increased. The air blast valve 20 cannot normally inject fuel from the nozzle tube 24 unless the compressed air pressure P reaches a predetermined pressure P1 or higher. Therefore, the compressed air pressure P
The fuel injection valve 36 is closed and the compressed air outflow passage 35 and the 21 dollar insertion hole 22
Do not supply fuel inside. During these periods (a) and (b), the nozzle rod 24 of the air blast valve 20 is opened and closed by controlling the solenoid 30, and the opening and closing of the nozzle rod 24 of the air blast valve 20 is performed to open and close the second dollar insertion hole 22, the compressed air outflow passage 35, the nozzle chamber 32, and the compressed air inflow passage. Air compressed within the combustion chamber 4 is fed into the combustion chamber 33.

Referring to FIG. 6, when only air is compressed, the pressure in the combustion chamber begins to rise at around 90 degrees before top dead center, reaches its maximum at top dead center, and reaches atmospheric pressure around 90 degrees after top dead center. Crank angle θA when the combustion chamber pressure rises to P1
At this point, the solenoid 30 is turned on and the nozzle roller 24 is opened. As a result, the compressed air in the combustion chamber 4 is
The air flows from the nozzle tube 24 into the twenty dollar insertion hole 22, the compressed air outflow passage 35, the nozzle chamber 32, and the compressed air inflow passage 33. The compressed air that has reached the compressed air inflow passage 35 is
A discharge valve (not shown) of the air compressor 48 prevents leakage to the suction port 48a side of the air compressor 48, and the compressed air pressure in the compressed air inlet passage 35 is controlled by the pressure regulator 4.
Since the predetermined pressure of 9 has not been reached, there is no leakage to the return pipe 50 side either. Next, at the crank angle θB when the combustion chamber pressure decreases to P1, the solenoid 30 is turned off,
The nozzle roller 24 is closed. In this way, since the compressed air pressure in the combustion chamber 4 is added to the discharge air pressure of the air compressor 48, the compressed air pressure in the compressed air inlet passage 33, etc. is increased faster than by the air compressor 48 alone. Become. Here, θA is about 45° before top dead center, and θB is about 45° after top dead center. Note that various aspects can be considered regarding the opening/closing timing of the nozzle roller 24.
For example, as shown in FIG. 7, the nozzle rod 24 may be opened at θA after both the supply and exhaust valves are closed, and closed at θB, which is slightly past the top dead center. Further, the pressure in the combustion chamber 4 is detected, and the nozzle rod 24 is opened only during a period when the pressure in the combustion chamber 4 is higher than the compressed air pressure in the compressed air inflow passage 33 detected by the pressure sensor 51. It's okay.

Referring again to FIG. 5, when the compressed air pressure P reaches P1, normal fuel injection is performed. That is, after the fuel injection valve 36 supplies fuel into the compressed air outflow passage 35 and the twenty-one dollar insertion hole 22 at a predetermined crank angle, the nozzle 24 of the air blast valve 20 is opened, whereby the fuel is injected into the air. At the same time, it is ejected from the nozzle tube 24 into the combustion chamber 4.

In this way, when starting the engine, the compressed air in the combustion chamber 4 is sent from the nozzle rod 24 into the twenty-one dollar insertion hole 22, the compressed air outflow passage 35, the nozzle chamber 32, and the compressed air inflow passage 33. Compressed air inflow passage 3
3. It is possible to increase the compressed air pressure inside etc. in a short time.
Therefore, fuel can be quickly injected into the combustion chamber 4. Therefore, the engine starting time can be shortened without using auxiliary compressed air generating means, and the engine startability can be improved.

FIG. 8 and FIG. 9 show a routine for executing the fuel air injection control of this embodiment. This routine is executed by an interrupt every 360 degrees of crank angle, for example, the first
It is activated every crank angle θS shown in FIG.

Referring to FIGS. 8 and 9, in step 100, the compressed air pressure P in the compressed air inflow passage 33, the intake air amount Q
1 engine rotation speed N and engine cooling water temperature TW are read. Next, in step 101, the starter switch 55 is turned on.
It is determined whether or not. If an affirmative determination is made, it is determined in step 102 whether P≧pt.

If the determination is negative, the process proceeds to step 103. In this case, the engine is started and the PDP is 1. Step 1
At step 03, it is determined whether the crank angle θ has reached θA (see FIG. 10). When θ becomes θA, the process proceeds to step 104, where the solenoid 30 is turned on and the nozzle rod 24 is opened. In step 105, θ is θB (see Figure 10).
It is determined whether the

When θ becomes θB, the routine proceeds to step 10fi, where the solenoid 30 is turned off and the nozzle nozzle 24 is closed, and this routine ends. If a negative determination is made in step 101, that is, during normal operation and not when the engine is started,
Proceed to step 107 to calculate Q/N. Step 1
In 08, Q/N. Fuel injection time TAU is calculated based on N and TW. In step 109, the fuel injection period crank angle θT (see FIG. 10) is calculated by TAU, and the process proceeds to step 112. When an affirmative determination is made in step 102, that is, when the engine is started and P≧P1, step 110 The starting fuel injection time TAUST^ is calculated from the cooling water temperature TW. TW and TA [I
The relationship with STA is as shown in FIG. 11, for example. In step 111, the fuel injection period crank angle θT is calculated from TAUST^. In step 112,
The fuel injection valve 36 opening crank angle θC (see FIG. 10) is calculated from the fuel injection valve 36 closing crank angle θD (see FIG. 10) and the fuel injection crank angle θT. Here θ
D is the fixed whale rank angle. In step 113, it is determined whether θ has reached θC. When θ reaches θC, the process proceeds to step 114, and the fuel injection valve 36 is opened. In step 115, it is determined whether θ has become θD. When θ=θD, the process proceeds to step 116, where the fuel injection valve 36 is closed, and fuel supply is completed.

In step 117, it is determined whether θ has reached the nozzle roller 24 opening crank angle θE (see FIG. 10). When θ becomes θE, the process advances to step 118 and the nozzle roller 24
is forced to open. As a result, fuel is injected into the combustion chamber 4 from the nozzle tube 24 using compressed air.

In step 119, θ is the nozzle roller 24 closing valve crank angle θ
It is determined whether or not it has become F (see FIG. 10).

When θ reaches θF, the routine proceeds to step 120, where the nozzle nozzle 24 is closed and the present routine ends. Here, θE and θF are fixed crank angles.

FIG. 12 shows a second step that indirectly determines whether the compressed air pressure P in the compressed air inflow passage 33 is equal to or higher than the predetermined pressure P1 in step 102 of the routine of FIG. The routine of the embodiment is shown below. This routine, like the routines shown in FIGS. 8 and 9, is executed by an interrupt every 360 degrees of crank angle.

Referring to FIG. 12, in step 130, counter C
Increment. C is initialized and reset to 0 when the engine is started. In step 131, it is determined whether C is 10 or more. If the judgment is negative,
In other words, if the engine rotates less than 10 times from the time the engine starts,
Proceed to step 103 and subsequent steps in FIGS. 8 and 9, and θA
and θB, the nozzle roller 24 is opened. Step 1
If an affirmative determination is made in step 31, the compressed air pressure has been sufficiently increased, so the process proceeds to step 110 and subsequent steps in FIGS. 8 and 9, and starting fuel injection is executed. Step 101
If a negative determination is made in step 132, that is, during normal operation and not when the engine is started, after resetting C in step 132,
The process proceeds to step 107 in FIGS. 8 and 9, and normal fuel injection by the air blast valve 20 is performed.

According to the second embodiment, it is possible to obtain the same effects as the above-described embodiments, and furthermore, the pressure sensor 51 can be made unnecessary.

Next, a third embodiment in which the compressed air in the combustion chamber 4 is sent into the air blast valve 20 at a different time will be described.

FIG. 13 shows the change in cylinder pressure when only air is compressed. Compression begins around 110 degrees before top dead center. When the compressed air pressure P in the compressed air inflow passage 33 is lower than, for example, the gauge pressure of 1.5 kg/crl when starting the engine, the combustion chamber 4 is discharged into the air blast valve 20 without supplying fuel to the air blast valve 20. Inject compressed air inside. As shown in Fig. 13, this period is 80 to 60 degrees before top dead center (θA1 to θBl in Fig. 14), and although not shown in Fig. 13, it is 60 to 80 degrees after top dead center ( Similarly, compressed air in the combustion chamber 4 is sent into the air blast valve 20 in θA2 to θB2 in FIG. 14.

During the period from 60 degrees before top dead center to 60 degrees after top dead center,
The pressure inside the cylinder increases and the pressure is overcome and the nozzle nozzle 24
To open the valve, a solenoid that generates a strong magnetic force is required, so turn off the solenoid 30 and close the nozzle rod 2.
4 is closed. Compressed air pressure P is 1. 5k
g/cl! 1 or more, fuel is injected into the combustion chamber 4 together with compressed air at an angle of 110 degrees to 95 degrees before top dead center, where the cylinder pressure is low, as shown in FIG.

FIG. 15 shows a routine for executing fuel air injection in this embodiment. The routine in FIG. 15 is almost the same as the routine in FIG.
The same processing as the routine shown in the figure is executed, and the explanation thereof will be omitted. Note that, similar to the routine shown in FIG. 8, the routine shown in FIG. 15 is followed by the routine shown in FIG. This routine is executed by an interrupt every 360 degrees of crank angle,
For example, it is activated at every crank angle θU shown in FIG.

Referring to FIG. 15, when it is determined in step 101 that the starter switch 55 is on, the process proceeds to step 180, where the compressed air pressure P is set to the gauge pressure 1. 5 kg/cut
It is determined whether or not the value is greater than or equal to the value. P<1. 5 kg/c
When ++f, the process goes to step 181 and the crank angle θ is θA.
1 (see FIG. 14). θ
When becomes θA1, the process proceeds to step 182, and solenoid 3
0 to open the nozzle roller 24. This causes the compressed air in the combustion chamber 4 to flow back into the air blast valve 20. In step 183, the crank angle θ is θB1
(See FIG. 14). θ is θB
When the solenoid 30 is
is turned off to close the nozzle roller 24. This stops the compressed air in the combustion chamber 4 from flowing into the air blast valve 20. Next, in step 185, it is determined whether the crank angle θ has reached θA2 (see FIG. 14). When θ reaches θA2, the process proceeds to step 186, where the nozzle rod 24 is opened again, and the air blast valve 20 is opened again.
Compressed air in the combustion chamber 4 is allowed to flow into the combustion chamber 4. In step 187, it is determined whether the crank angle θ has reached θB2 (see FIG. 14). When θ reaches θB2, the routine proceeds to step 188, where the nozzle nozzle 24 is closed, the flow of compressed air into the air blast valve 20 is stopped, and this routine ends.

On the other hand, step 180 odor rP ≧ 1.5 kg/cut
If it is determined that this is the case, the process proceeds to step 110, and the same processing as the routine shown in FIG. 8 is performed.

In this embodiment as well, the startability of the engine can be improved as in the first embodiment.

In addition, instead of the pressure sensor 51, it is turned on at 1.5 kg/ctl or less. A pressure switch that turns off when the pressure exceeds 5 kg/CTl may be used.

Next, a fourth embodiment in which a check valve 80 is provided in the compressed air inlet passage 33 immediately before the air blast valve 20 will be described.

Referring to FIG. 16, a check valve 80 is provided in the compressed air inlet passage 33 immediately before one end 32a of the nozzle chamber 32. As shown in FIG.

This check valve 80 only allows flow from the compressed air inlet passage 33 toward the nozzle chamber 32, and prohibits flow in the opposite direction.

Next, the operation of this embodiment will be explained with reference to FIG.
When the starter switch 55 is turned on at point (c), the air compressor 48 is driven by the engine and the pressure P in the compressed air supply passage 33 is gradually increased. On the other hand, at the initial stage of engine startup, the nozzle roller 24 is opened and closed, and the 21 dollar insertion hole 22, the compressed air outflow passage 35 and the nozzle chamber 32 are opened and closed.
The compressed air in the combustion chamber 4 is allowed to flow into the combustion chamber 4. This compressed air is prevented from flowing out into the compressed air inflow passage 33 by the check valve 80. Therefore, the volume to which compressed air is supplied at the time of starting the engine can be reduced.
When the engine rotates, for example, twice due to cranking, the pressure of the compressed air inside the pump increases to P1 or more, which is the pressure at which the air blast valve 20 can inject fuel. Subsequently, at a predetermined crank angle of the third rotation of the engine, fuel is supplied from the fuel injection valve 36 into the compressed air outflow passage 35 and the twenty-one dollar insertion hole 22,
(2) At the time, the nozzle chamber 32 and the compressed air outflow passage 3
The compressed air in the 5 and 21 dollar insertion holes 22 causes the supplied fuel to be ejected from the nozzle row 24. Subsequently, the air-fuel mixture is ignited and combusted, which causes the engine rotational speed to rapidly increase and the rotational speed of the air compressor 48 to increase rapidly as well. Thus, the compressed air inflow passage 33
The pressure inside the air compressor 4 suddenly increases.
The compressed air supplied by
2.

When the pressure in the compressed air inflow passage 33 is lower than the air blast valve fuel injection enable pressure P1 at the fourth rotation of the engine, fuel is not supplied from the fuel injection valve 36 and fuel injection from the nozzle nozzle 24 is not performed. In this case as well, the engine rotational speed is increased due to the combustion of the air-fuel mixture during the third rotation of the engine, and the pressure within the compressed air inlet passage 33 is rapidly increased.

When P reaches P1 at the fifth rotation of the engine (e), normal fuel injection is performed, and the fuel injection valve 36 is opened at a predetermined crank angle.
After supplying fuel from the nozzle tube 24, the valve is opened.
The supplied fuel is injected into the combustion chamber 4. Therefore, the starting time can be shortened without using auxiliary air pressure generating means. The period until the air blast valve 20 becomes capable of fuel injection depends on the capacity of the air compressor 48 and the compressed air supply passage (compressed air inflow passage 33, nozzle chamber 32).
, the volume of the compressed air outflow passage 35 and the dollar insertion hole 22).

Opening/closing timing θA of the nozzle roller 24. θB is the same as in FIG. These θA and θB are set so that the pressure in the compressed air outflow passage 35 becomes sufficiently higher than P1 by opening and closing the nozzle nozzle 24 twice, as shown in FIG. 17, for example.

FIG. 18 shows a routine for executing fuel air injection in this embodiment. The routine in FIG. 18 is almost the same as the routine in FIG. 8, and the same step number executes the same process, so the explanation will be omitted. Note that, similar to FIG. 8, the routine in FIG. 18 is followed by the routine in FIG. 9. The routine shown in FIG. 18, like the routine shown in FIG. 8, is executed by an interrupt every 360 degrees of crank angle.

Referring to FIG. 18, when it is determined in step 101 that the starter switch 55 is on, the process proceeds to step 140, where the engine rotation number counter C is incremented. A counter C and a flag F, which will be described later, are initialized to 0 when the ignition switch is turned on. In step 141, it is determined whether C is, for example, 2 or less. If the engine speed is 2 revolutions or less, the process proceeds to step 103 and below, where the nozzle rod 24 is opened and closed at a predetermined crank angle, and the compressed air in the combustion chamber 4 is discharged into the needle insertion hole 22, the compressed air outflow passage 35, and the nozzle chamber 32. Introduce air. When the engine reaches 3 revolutions or more, the process proceeds to step 142 and flag F is set.
Determine whether or not is 1. Initially F is 0, so step 1
The process proceeds to step 43, where F is set to 1, and fuel is injected from the nozzle tube 24 in steps 110 and thereafter.

This causes the air-fuel mixture to ignite and burn, causing the engine speed to rise rapidly. In the next processing cycle, step 14
The process proceeds from step 2 to step 144, where it is determined whether P≧P1. When the compressed air pressure P is lower than the air blast valve operating pressure P1, this routine ends without executing anything. When P≧P1, the process proceeds to step 110 and below, and the fuel flows to the nozzle 24.
It is made to gush from

Note that the check valve 80 does not need to be provided at the position shown in FIG. 16, but may be provided in the compressed air supply passageway that is close to the air compressor 48 from the nozzle chamber 32 and close to the nozzle chamber 32.

Further, instead of the check valve 80, a solenoid valve may be used to control opening and closing.

〔Effect of the invention〕

Since the compressed air in the combustion chamber is sent into the compressed air passage when starting the engine, the starting time can be shortened without using an auxiliary air pressure generating means, and the startability of the engine can be improved.

[Brief explanation of the drawing]

Fig. 1 is a diagram of the overall structure of the first embodiment, Fig. 2 is a bottom view of the inner wall surface of the cylinder head, Fig. 3 is a side sectional view of the two-cycle engine, and Fig. 4 is a partial sectional view of the air blast valve. 5 and 6 are operation explanatory diagrams; FIG. 7 is a line diagram showing the nozzle valve opening period; FIGS. 8 and 9 are flowcharts for carrying out the first embodiment; 11 is a diagram showing the relationship between water temperature and starting fuel injection time, FIG. 12 is a flow chart for carrying out the second embodiment, and FIG. FIG. 14 is a diagram showing the change in cylinder pressure with respect to the crank angle. FIG. 14 is a diagram showing the nozzle opening period, etc. of the third embodiment. FIG. Figure 16 is a partially sectional side view of the air blast valve of the fourth embodiment;
The figure is an explanatory diagram of the operation of the fourth embodiment, and FIG. 18 is a flowchart for executing the fourth embodiment. 4... Combustion chamber, 22... Twenty-one dollar insertion hole, 24... Nozzle hole, 32... Nozzle chamber, 35... Compressed air outflow passage, 48... Air compressor, 20... Air blast valve, 23... Needle, 30... Solenoid, 33... Compressed air inflow passage, 36... Fuel injection valve, 60... Electronic control unit.

Claims (1)

[Claims] A nozzle opening is formed at the tip of the compressed air passage facing into the combustion chamber, and an opening/closing valve that electromagnetically opens and closes the nozzle opening is arranged at the nozzle opening, and the fuel supplied into the compressed air passage is transferred to the engine. In the fuel injection device, the fuel is injected from the nozzle port into the combustion chamber by compressed air supplied into the compressed air passage from a compressed air supply source driven by a compressed air supply source. The internal combustion engine is configured to open the on-off valve to send compressed air in the combustion chamber into the compressed air passage when the supply is stopped and the pressure in the combustion chamber exceeds a predetermined pressure. Fuel injection device.