JP2689696B2 - Fuel injection control device for two-cycle internal combustion engine - Google Patents

Description

The present invention relates to a fuel injection control device for a two-cycle internal combustion engine.

[Conventional technology]

A nozzle port arranged in the combustion chamber, a compressed air passage communicating with the nozzle port, an opening / closing valve for controlling opening / closing of the nozzle port,
An air blast valve including a fuel injection valve for injecting fuel into the compressed air passage is known (see Japanese Patent Publication No. 1-503555). In this air blast valve, compressed air is supplied to the air blast valve by using an engine-driven air supply pump in order to inject the fuel into the combustion chamber by the compressed air. However, when the engine-driven air supply pump is used as described above, the compressed air pressure does not immediately rise at the time of engine startup, and thus fuel cannot be injected into the combustion chamber by compressed air immediately at engine startup. Therefore, in this air blast valve, the on-off valve is opened during the compression stroke when the engine is started, and the compressed air in the combustion chamber compressed by the piston is pushed through the nozzle port into the compressed air passage in the air blast valve, The fuel is injected into the combustion chamber by the compressed air when the compressed air pressure in the passage becomes sufficiently high.

[Problems to be solved by the invention]

By the way, in a multi-cylinder internal combustion engine, for example, a reference signal indicating that the first cylinder is at the top dead center is generated, and which cylinder is in what stroke is determined based on this reference signal. Therefore, in a multi-cylinder internal combustion engine, when the on-off valve is opened during the compression stroke like the above-mentioned air blast valve, a reference signal is generated and the on-off valve is opened only after it is determined which cylinder is in which stroke. The compressed air cannot be pushed into the air blast valve by opening the valve, and the compressed air cannot be pushed into the air blast valve until the reference signal is generated. Therefore, there is a problem that it takes time for the compressed air pressure in the air blast valve to rise when the engine is started.

[Means for solving the problem]

In order to solve the above problems, according to the present invention, as shown in the configuration diagram of the invention of FIG. 1, a nozzle opening, a compressed air passage communicating with the nozzle opening, and an opening / closing valve for controlling opening / closing of the nozzle opening, An air blast valve 9 having a fuel injection valve for injecting fuel into the compressed air passage is provided for each cylinder A,
The compressed air passage of each air blast valve 9 is connected to the compressed air distribution chamber 20 common to each cylinder A, and compressed air is supplied into the compressed air distribution chamber 20 by an engine-driven air supply pump. In the fuel injection control device in which the nozzle openings of 9 are opened in the combustion chambers of the corresponding cylinders A,
A starter switch 63, a reference signal generating means B for generating a reference signal indicating that any one of the specific cylinders is at a specific crank angle, and a crank angle during which the reference signal is generated after the starter switch 63 is turned on. And an open / close valve opening means C for opening and closing the open / close valves of the air blast valves A of the two cylinders which are deviated by 180 degrees.

(Operation)

The air in the combustion chamber of one of the two cylinders whose crank angle is shifted by 180 degrees is in a compressed state. Therefore, when the open / close valve of the air blast valve of the cylinder whose crank angle is deviated by 180 degrees is opened, the compressed air in the combustion chamber of the cylinder in which the air in the combustion chamber is compressed is compressed air through the nozzle port and the compressed air passage. It is pushed into the distribution chamber, thus increasing the compressed air pressure in the compressed air distribution chamber. When the compressed air pressure in the compressed air distribution chamber rises, compressed air flows out from the air blast valve of the other cylinder, but the compressed air is compared with the pressure difference in the combustion chamber of the cylinder where the air is compressed and the compressed air distribution chamber. The pressure difference between the pressure in the combustion chamber of the cylinder and the pressure in the compressed air distribution chamber is quite small. Therefore, the amount of compressed air pushed into the compressed air distribution chamber is larger than the amount of compressed air flowing out of the compressed air distribution chamber, so that the compressed air pressure in the compressed air distribution chamber is increased before the reference signal is generated.

〔Example〕

FIG. 2 shows an overall view of the two-cycle internal combustion engine. Referring to FIG. 2, 1 is a cylinder block, 2 is a reciprocating piston in the cylinder block 1, 3 is a cylinder head fixed on the cylinder block 1, and 4 is formed between the piston 2 and the cylinder head 3. Combustion chamber, 5 air supply valve, 6 air supply port, 7 exhaust valve, 8 exhaust port,
9 denotes air blast valves for injecting fuel together with the compressed air into the combustion chamber 4. Although not shown in the drawings, an ignition plug is disposed at the center of the inner wall surface of the cylinder head 3. The air supply port 6 is connected to a surge tank 11 via an air supply branch pipe 10, and the surge tank 11 is connected to an air cleaner 15 via an engine-driven mechanical supercharger 12, an air supply duct 13 and an air flow meter 14. It Throttle valve in the air supply duct 13
16 are arranged. As shown in FIG. 3, the two-cycle engine shown in FIG. 2 is a four-cylinder two-cycle engine consisting of first cylinder # 1, second cylinder # 2, third cylinder # 3, and fourth cylinder # 4. An air blast valve 9 is provided for each cylinder.

FIG. 4 shows an enlarged sectional view of each air blast valve 9. Referring to FIG. 4, a straight compressed air passage 31 is formed in the housing 30 of the air blast valve 9, and a nozzle located in the combustion chamber 4 (FIG. 2) is formed at the tip of the compressed air passage 31. A mouth 32 is formed. An on-off valve 33 is disposed in the compressed air passage 31, and a nozzle port is provided at an outer end of the on-off valve 33.
A valve body 34 for controlling the opening and closing of 32 is integrally formed. A compression spring 35 is disposed in the housing 30 coaxially with the on-off valve 33.
The movable core 36 urged toward the on-off valve 33 by the opening and the solenoid 37 for sucking the movable core 36 are arranged.
The inner end of the on-off valve 33 is brought into contact with the end face of the movable core 36 by a compression spring 38, and the spring force of the compression spring 38 is stronger than that of the compression spring 35.
It is closed by 33 valve bodies 34. When the solenoid 37 is energized, the movable core 36 moves in the direction of the on-off valve 33, and as a result, the valve element 34 of the on-off valve 33 opens the nozzle port 32. On the other hand, a compressed air passage 39 that extends obliquely from the compressed air passage 31 is branched from the compressed air passage 31, and the compressed air passage 39 is connected to a compressed air supply port 40. A fuel injection valve 41 is attached to the housing 30, and a nozzle hole 42 of the fuel injection valve 41 is provided.
From there, fuel is injected into the compressed air passage 39.

As shown in FIG. 2, an air blast air passage 17 is branched from the air supply duct 13 between the air flow meter 14 and the throttle valve 16, and the air blast air passage 17 is an air supply pump including an engine-driven vane pump. It is connected to the compressed air distribution chamber 20 via 18 and the compressed air passage 19.
The compressed air distribution chamber 20 is connected to a compressed air supply port 40 of an air blast valve 9 provided for each cylinder. In the compressed air passage 19, a pressure regulating valve 21 for maintaining the compressed air pressure in the compressed air distribution chamber 20 at a predetermined constant pressure is arranged, and excess compressed air is supplied through a compressed air return passage 22. It is returned into the duct 13. Therefore, after the engine is started, the compressed air passages 31, 39 of the air blast valve 9 are filled with compressed air having a constant pressure.

FIG. 5 shows the opening periods of the intake valve 5 and the exhaust valve 7, the fuel injection period from the fuel injection valve 41, and the regular opening period P of the on-off valve 33 after the fuel injection is started, that is, air blast. The regular opening period P of the valve 9 is shown. As shown in FIG. 5, in the embodiment shown in FIG. 2, the exhaust valve 7 opens before the air supply valve 5 and closes first. Further, as shown in FIG. 5, before the opening / closing valve 33 is opened, that is, before the air blast valve 9 is opened, fuel is injected from the fuel injection valve 41 toward the compressed air in the compressed air passage 39. Is jetted. Then air blast valve 9
When the valve is opened, the injected fuel is injected from the nozzle port 32 into the fuel chamber 4 together with the compressed air. On the other hand, as shown in FIG. 2, a mask wall 23 is formed on the inner wall surface of the cylinder head 3 to cover the opening of the air supply valve 5 on the exhaust valve 7 side for the full opening period of the air supply valve 5. Therefore, when the air supply valve 5 is opened, fresh air is supplied from the air supply port 6 into the combustion chamber 4 through the opening of the air supply valve 5 opposite to the exhaust valve 7. As a result, fresh air flows along the peripheral wall surface of the combustion chamber 4 as shown by the arrow S, and thus good loop scavenging is performed.

Each air blast valve 9 is an electronic control unit shown in FIG.
Controlled based on 50 output signals. This electronic control unit 50 is a ROM interconnected by a bidirectional bus 51.
(Read-on memory) 52, RAM (random access memory) 53, CPU (microprocessor) 54, input port 55, and output port 56 are provided. Air flow meter
14 generates an output voltage proportional to the intake air amount, and this output voltage is input to the input port 55 via the AD converter 57.
Further, a water temperature sensor 58 that generates an output voltage proportional to the engine cooling water temperature is attached to the cylinder block 1, and the output voltage of the water temperature sensor 58 is input via an AD converter 59.
Entered in 55. A reference position sensor 61 and a crank angle sensor 62 are attached to the distributor 60.
The reference position sensor 61 generates a reference signal G when the first cylinder reaches 5 ° after top dead center, and this reference signal G is input to the input port.
Entered in 55. On the other hand, the crank angle sensor 62 generates an output pulse each time the crankshaft rotates 30 degrees, and this output pulse is input to the input port 55. Further, the operation signal of the starter switch 63 is input to the input port 55.
On the other hand, the output port 56 is connected to the solenoid 37 and the fuel injection valve 41 of each air blast valve 9 via the corresponding drive circuits 64 and 65.
Connected to.

Next, the control of the air blast valve 9 will be described with reference to FIG. In addition, in FIG. 6, the ignition sequence is 1-4-2-3.
Therefore, the crank angles of the cylinders are deviated by 90 degrees according to the ignition sequence.

Referring to FIG. 6, as described above, the reference signal G is generated 5 degrees after the top dead center (360 ° CA) of the first cylinder # 1. On the other hand, the 30 ° signal generated by the crank angle sensor 62 is accurately generated with reference to the crank angle of 0 ° (= 360 °). When the 30 ° signal is first generated after the reference signal G is generated, it is determined that this time is 30 ° after the top dead center of the first cylinder # 1, and the crank angle positions of all the cylinders are determined on the basis of this.

As shown in FIG. 6, from when the starter switch is turned on until the reference signal G is generated, the crank angle is
Two cylinders displaced by 180 °, in the embodiment shown in FIG. 6, the opening / closing valve 33 of the air blast valve 9 of the first cylinder # 1 and the second cylinder # 2
That is, the air blast valve A1 of No. 1 cylinder # 1 and No. 2 cylinder #
The second air blast valve A2 is opened. As can be seen from FIG. 5, in the two cylinders whose crank angles are deviated by 180 °, when the intake valve 5 and the exhaust valve 7 of one cylinder are opened and the inside of the combustion chamber 4 is almost atmospheric pressure, The air supply valve 5 and the exhaust valve 7 of the cylinder are closed, and the air in the combustion chamber 4 is in a compressed state. Now, if the intake valve 5 and the exhaust valve 7 of the first cylinder # 1 are closed, the air in the combustion chamber 4 of the first cylinder # 1 is in a compressed state. The compressed air in the combustion chamber 4 of the first cylinder # 1 is sent into the compressed air distribution chamber 20 via the compressed air passages 31 and 39 in the air blast valve A1. As a result, the compressed air pressure in the compressed air distribution chamber 20 increases. When the compressed air pressure in the compressed air distribution chamber 20 thus rises, this compressed air flows out into the combustion chamber 4 of the second cylinder # 2 via the air blast valve A2. However, the pressure difference between the compressed air pressure in the combustion chamber 4 of the first cylinder # 1 and the compressed air pressure in the compressed air distribution chamber 20 is 2
Compressed air pressure in the combustion chamber 4 of cylinder # 2 and compressed air distribution chamber 20
It is much larger than the pressure difference with the compressed air pressure inside. Therefore, the amount of compressed air sent from the combustion chamber 4 of the first cylinder # 1 into the compressed air distribution chamber 20 is 2 from the compressed air distribution chamber 20.
The amount of compressed air flowing into the combustion chamber 4 of the # 2 cylinder # 2 becomes larger, and thus the compressed air pressure in the compressed air distribution chamber 20 is increased. In this way, the compressed air pressure in the compressed air distribution chamber 20 is increased between the time when the starter switch is turned on and the time when the reference signal G is generated.

On the other hand, when the reference signal G is generated, the crank angle of each cylinder is known. Therefore, at this time, the air blast valve 9 of each cylinder
As shown by K in FIG. 5, the valve is opened from about 60 ° before top dead center to about 60 ° after top dead center. In the embodiment shown in FIG. 6, this is repeated 3 times. That is, as shown in FIG. 6, when the reference signal G is generated, first, the air blast valve A4 of the fourth cylinder # 4 is opened and the fourth cylinder # 4 is opened.
Compressed air in the combustion chamber 4 of No. 4 is sent into the compressed air distribution chamber 20, then the air blast valve A2 of the second cylinder # 2 is opened, and compressed air in the combustion chamber 4 of the second cylinder # 2 is opened. Is sent into the compressed air distribution chamber 20, then the air blast valve A3 of the third cylinder # 3 is opened, and the compressed air in the combustion chamber 4 of the third cylinder # 3 is sent into the compressed air distribution chamber 20. Be done. As a result, the compressed air pressure in the compressed air distribution chamber 20 gradually increases.

Next, when a predetermined crank angle has elapsed after the reference signal G was generated, fuel injection from the fuel injection valve 41 is started, and the air blast valve 9 is opened at the regular valve opening timing P. In the embodiment shown in FIG. 6, first, fuel is injected into the air blast valve 2A from the fuel injection valve 41 of the air blast valve 2A of the second cylinder # 2, and then the air blast is performed when the exhaust valve 7 is closed. The valve 2A is opened, and the fuel is injected into the combustion chamber 4 of the second cylinder # 2 together with the compressed air.
Next, the air blast valve 9 of each cylinder is sequentially arranged according to the ignition order.
From which compressed air is injected with fuel.

Next, when the engine starts self-driving, the air supply pump 18
In order to increase the discharge amount of the compressed air, the compressed air pressure in the compressed air distribution chamber 20 rises to a predetermined constant pressure, for example, 3 kg / cm ² .

FIG. 7 shows a control routine of the air blast valve 9 at the time of starting the engine, and this routine is executed by interruption at regular time intervals. FIG. 8 shows an interrupt routine by the reference signal G. When the reference signal G is generated, the flag is set as shown in FIG.

Referring to FIG. 7, first, at step 100, it is judged from the output signal of the water temperature sensor 58 whether the engine cooling water temperature T is higher than a predetermined constant temperature, for example, 40 ° C. When T40 ° C., step 101 is proceeded to, where it is judged if the starter switch 63 is on or not. When the starter switch 63 is on, the routine proceeds to step 102, where it is judged if the flag is set. When the starter switch 63 is turned on, the flag has been reset, so the routine proceeds to step 103. In step 103, the first cylinder #
The air blast valve A1 of No. 1 is opened. Next, at step 104, the air blast valve A2 of the second cylinder # 2 is opened.

Next, when the reference signal G is generated and the flag is set, the routine proceeds from step 102 to step 105, where the air blast valve A1 of the first cylinder # 1 is closed, and then step 106
At 2, the air blast valve A2 of the second cylinder # 2 is closed. Next, at step 107, before the top dead center of the fourth cylinder # 4 6
Data for opening the air blast valve A4 between 0 ° and 60 ° after top dead center is output to the output port 56, and then step
In 108, the data for opening the air blast valve A4 is output to the output port 56 between 60 ° before the top dead center and 60 ° after the top dead center in the second cylinder # 2, and then in the step 109, in the third cylinder # 2. Three
Air blast valve between 60 ° before top dead center and 60 ° after top dead center
The data for opening A3 is output to the output port 56.

It should be noted that when the engine cooling water temperature T is higher than 40 ° C., it means that the engine has just stopped, and at this time, the compressed air pressure in the compressed air distribution chamber 20 is considered to be sufficiently high. Therefore, at this time, the processing routine is immediately completed, and the air blast valves A1, A
The valve opening process of 2, A3, A4 is not performed.

FIG. 9 shows a fuel injection processing routine. This routine is executed every fixed crank angle, for example, every 90 degrees. The embodiment shown in FIG. 9 shows the case where an interrupt is executed at the timing (90 ° CA, 180 ° CA, 270 ° CA, 360 ° CA) shown by the chain line in FIG. Since the crank angle cannot be determined unless the reference signal G is generated, this injection processing routine is executed after the reference signal G is generated.

Referring to FIG. 9, first, at step 200, it is judged if the engine cooling water temperature T is higher than 40 ° C. or not.
When the temperature is T40 ° C., the routine proceeds to step 201, where it is judged if the crank angle θ from the generation of the reference signal G to the present time exceeds the constant crank angle θ ₀ shown in FIG. 6, that is, 230 °. When θ <θ ₀ , the processing routine is completed. On the other hand, when θθ ₀ , step 202
Next, the fuel injection amount is calculated based on the intake air amount detected by the air flow meter 14 and the engine speed calculated from the output pulse of the crank angle sensor 62. Next, at step 203, the fuel injection valve 41 of the cylinder to be injected next,
In the embodiment shown in FIG. 6, data for injecting fuel from the fuel injection valve 41 of the second cylinder # 2 is output to the output port 56.
Next, at step 204, data for opening the air blast valve 9 of the cylinder from which fuel is injected from the fuel injection valve 41 at the regular valve opening timing P is output to the output port 56. Thus, the fuel is injected from the air blast valve 9 together with the compressed air, and the engine is started.

On the other hand, when it is judged at step 200 that T> 40 ° C., the routine immediately jumps to step 202 and the injection action of compressed air and fuel from the air blast valve 9 is started.

The present invention can also be applied to a 6-cylinder 2-cycle engine or a 2-cycle period with more cylinders.
For example, when the present invention is applied to a 6-cylinder 2-cycle internal combustion engine in which the ignition sequence is 1-6-2-4-3-5, the crank angle from when the starter switch 63 is turned on until the reference signal G is generated is increased. Are shifted by 180 degrees, for example, the air blast valves of the first cylinder and the fourth cylinder are opened.

〔The invention's effect〕

Since the compressed air pressure in the compressed air distribution chamber is increased before the reference signal is generated, the engine start time can be shortened.

[Brief description of the drawings]

1 is a block diagram of the invention, FIG. 2 is an overall view of a two-cycle internal combustion engine, FIG. 3 is a plan view of the two-cycle internal combustion engine shown in FIG. 2, and FIG. 4 is an enlarged side sectional view of an air blast valve. , Fifth
Fig. 6 is a diagram showing the open / close period of the air supply / exhaust valve, the open period of the air blast valve, etc., Fig. 6 is a time chart showing the open timing of the air blast valve in a 4-cylinder 2-cycle engine, and Fig. 7 is A flowchart showing a start-up processing routine,
FIG. 8 is a flow chart showing an interruption routine by a reference signal, and FIG. 9 is a flow chart showing an injection processing routine. 9 ... Air blast valve, 18 ... Air supply pump, 20 ... Compressed air distribution chamber, 31,39 ... Compressed air passage, 32 ... Nozzle port, 33 ... Open / close valve, 41 ... Fuel injection valve, 63 …… Starter switch.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-95771 (JP, A) Actual development 1-166272 (JP, U) Special table 1-503555 (JP, A) Special table 1- 503554 (JP, A)

Claims (1)

(57) [Claims] 1. An air blast valve having a nozzle opening, a compressed air passage communicating with the nozzle opening, an opening / closing valve for controlling opening / closing of the nozzle opening, and a fuel injection valve for injecting fuel into the compressed air passage. Is provided for each cylinder, the compressed air passage of each air blast valve is connected to a compressed air distribution chamber common to each cylinder, and compressed air is supplied to the compressed air distribution chamber by an engine-driven air supply pump. In a fuel injection control device in which the nozzle ports of the blast valves are opened in the combustion chambers of the corresponding cylinders, a starter switch and a reference signal generation that generates a reference signal indicating that any one of the specific cylinders is at a specific crank angle And the opening and closing valves of the air blast valves of the two cylinders whose crank angles are shifted by 180 degrees while the reference signal is generated after the starter switch is turned on. The fuel injection control apparatus for two-cycle internal combustion engine provided with the valve closing valve opening means.