JPH0472461A - Fuel injection control device for two-cycle internal combustion engine - Google Patents

Abstract

PURPOSE:To shorten engine starting time by providing a switching valve opening means for opening the switching valves of the air blast valves of two cylinders shifted by 180 deg. in the crank angle during a reference signal generating process. CONSTITUTION:Air is compressed in the combustion chamber 4 of either one of two cylinders shifted by 180 deg. in the crank angle. Accordingly, when the switching valve of the air blast valve 9 of this cylinder with air in the combustion chamber 4 being in the compressed state is opened, the compressed air in the combustion chamber 4 of this cylinder is pushed into a compressed air distribution chamber 20, and this compressed air pressure rises. With this rise of the compressed air pressure, compressed air from the air blast valve 9 of the other cylinder flows out, but pressure difference between the combustion chamber 4 of the other cylinder from which the compressed air flows out and the compressed air distribution chamber 20 is considerably smaller than the pressure difference between the combustion chamber 4 of the compressed cylinder and the compressed air distribution chamber 20. The compressed air quantity pushed into the compressed air distribution chamber 20 is thereby larger, so that the compressed air pressure in the compressed air distribution chamber 20 is boosted before the generation of a reference signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection control device for a two-stroke internal combustion engine.

[Conventional technology]

An air blast valve is known, which consists of a nozzle port arranged in a combustion chamber, a compressed air passage leading to the nozzle port, an on-off valve that controls opening and closing of the nozzle port, and a fuel injection valve for injecting fuel into the compressed air path. (Special table Hei 1-503555
(see publication). This air blast valve uses an engine-driven air supply pump to supply compressed air to the air blast valve in order to inject fuel into the combustion chamber using compressed air. However, when an engine-driven air supply pump is used in this manner, the compressed air pressure does not rise immediately upon starting the engine, and thus fuel cannot be injected into the combustion chamber by compressed air immediately upon starting the engine. Therefore, in this air blast valve, the on-off valve is opened during the compression stroke during the slight start, and the compressed air compressed by the piston is pushed into the compressed air passage inside the air blast valve through the nozzle port, and compressed. When the compressed air pressure in the air passage becomes high enough, the compressed air injects fuel into the combustion chamber.

[Problem to be solved by the invention]

In a multi-cylinder internal combustion engine, for example, a reference signal indicating that the first cylinder is at top dead center is generated, and based on this reference signal, it is determined which cylinder is in which stroke. Therefore, in a multi-cylinder internal combustion engine, if the on-off valve is opened during the compression stroke like the above-mentioned air blast valve, the on-off valve must be opened only after a reference signal is generated and it is determined which cylinder is in which stroke. Compressed air cannot be forced into the air blast valve by opening the valve, and compressed air cannot be forced into the air blast valve until the reference signal is generated. Therefore, there is a problem in that it takes time for the compressed air pressure within the air blast valve to rise during the slight start.

[Means to solve the problem]

In order to solve the above problems, according to the present invention, as shown in the configuration diagram of the invention in FIG. An air blast valve 9 equipped with a fuel injection valve for injecting fuel into a compressed air passage is provided for each cylinder A, and the compressed air passage of each air blast valve 9 is connected to a compressed air distribution chamber common to each cylinder A. 20 and an engine-driven air supply pump supplies compressed air into the compressed air distribution chamber 20, and the nozzle port of each air blast valve 9 is opened into the combustion chamber of the corresponding cylinder A. In the device, a starter switch 63, a reference signal generating means B that generates a reference signal indicating that a specific cylinder is at a specific crank angle, and a reference signal is generated after the starter switch 63 is turned on. The crank angle is 18
It is equipped with on-off valve opening means C for opening the on-off valves for the air blast valves of two cylinders that are shifted by 0 degrees.

[For production]

In two cylinders whose crank angles differ by 180 degrees, the air in the combustion chamber of one of the cylinders is compressed. Therefore, when the on-off 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 in a compressed state flows through the nozzle port and the compressed air passage. The air is forced into the distribution chamber, thus increasing the compressed air pressure within the compressed air distribution chamber. When the compressed air pressure in the compressed air distribution chamber increases, compressed air flows out from the air blast valve of the other cylinder, but the compressed air is smaller than the pressure difference between the pressure in the combustion chamber of the cylinder where the air is being compressed and the pressure in the compressed air distribution chamber. The pressure difference between the pressure in the combustion chamber of the outgoing cylinder and the compressed air distribution chamber is fairly small. Therefore, the amount of compressed air pushed into the compressed air distribution chamber is greater than the amount of compressed air flowing out from the compressed air distribution chamber, so that the compressed air pressure in the compressed air distribution chamber increases before the reference signal is generated.

〔Example〕

FIG. 2 shows an overall diagram of a two-stroke internal combustion engine.

Referring to FIG. 2, 1 is a cylinder block, 2 is a piston that reciprocates within the cylinder block 1, 3 is a cylinder head fixed on the cylinder block 1, and 4 is a cylinder formed between the piston 2 and the cylinder head 3. combustion chamber,
5 is an air supply valve, 6 is an air supply boat, 7 is an exhaust valve, 8 is an exhaust port, and 9 is an air blast valve that injects fuel together with compressed air into the combustion chamber 4. Although not shown in the drawings, an ignition plug is arranged 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 engine-driven mechanical supercharger 12, an air supply duct [3, and an air flow meter 14].
It is connected to the air cleaner 15 via. Air supply duct 1
A throttle valve 16 is disposed within the throttle valve 3 . As shown in Fig. 3, the two-stroke engine shown in Fig. 2 has one aromatic cylinder #1.
．． It consists of a 4-cylinder, 2-stroke engine consisting of 2 aromatic cylinders #2, 3rd cylinder #3, and 4 aromatic cylinders #4, and each cylinder is provided with an air blast valve 9, respectively.

FIG. 4 shows an enlarged sectional view of each air blast valve 9. Fourth
Referring to the figure, a straight compressed air passage 31 is formed in the nozzle 30 of the air blast valve 9, and a combustion chamber 4 (see Fig. 2) is located at the tip of this compressed air passage 31.
A nozzle opening 32 located inside is formed. An on-off valve 33 is disposed within the compressed air passage 31, and a valve body 34 for controlling opening and closing of the nozzle port 32 is integrally formed at the outer end of the on-off valve 33. Inside the housing 30, a movable core 36 which is disposed coaxially with the on-off valve 33 and is biased toward the on-off valve 33 by a compression spring 35, and a solenoid 37 for attracting the movable core 36 are arranged. Ru. The inner end of the on-off valve 33 is brought into contact with the end surface of the movable core 36 by a compression spring 38, and the spring force of the compression spring 38 is
Since the spring force is stronger than the spring force of 5, the nozzle port 32 is normally used as the on-off valve 3.
It is closed by the valve body 34 of No. 3. solenoid 37
When the movable core 36 is energized, the movable core 36 moves toward the on-off valve 33, and as a result, the valve body 34 of the on-off valve 33 opens the nozzle port 32. On the other hand, a compressed air passage 39 is branched from the compressed air passage 31 and extends diagonally from the compressed air passage 31.
This compressed air passage 39 is connected to a compressed air supply port 40 . A fuel injection valve 41 is attached to the housing 30,
Fuel is injected into the compressed air passage 39 from the nozzle hole 42 of the fuel injection valve 41 .

As shown in FIG. 2, an air blasting air passage 17 is branched from the air supply duct 13 between the air flow meter 14 and the throttle valve 16.
7 is an air supply pump 1 consisting of an engine-driven vane pump.
8 and compressed air distribution chamber 20 via compressed air passage 19
connected to. This compressed air distribution chamber 20 includes compressed air supply ports 4 of air blast valves 9 provided for each cylinder.
Concatenated to 0. A pressure regulating valve 21 is disposed in the compressed air passage 19 to maintain the compressed air pressure in the compressed air distribution chamber 20 at a predetermined constant pressure, and excess compressed air is returned to the supply air via the compressed air return passage 22. It is returned into the duct 13. Therefore, after the engine has been started, the compressed air passages 31, 39 of the air blast valve 9 are filled with compressed air at a constant pressure.

FIG. 5 shows the opening period of the intake valve 5 and the exhaust valve 7, the period of fuel injection from the fuel injection valve 41, and the regular opening period P of the on-off valve 33 after fuel injection is started, that is, the air blast. The normal valve opening period P of the valve 9 is shown.

As shown in FIG. 5, in the embodiment shown in FIG.
opens before the air supply valve 5, and closes before the air supply valve 5. Further, as shown in FIG. 5, before the on-off valve 33 opens, that is, before the air blast valve 9 opens, fuel is injected from the fuel injection valve 41 into the compressed air in the compressed air passage 39. Injected. Next, when the air blast valve 9 opens, the nozzle port 32
Injected fuel is injected into the fuel chamber 4 together with compressed air. On the other hand, as shown in FIG. 2, the air supply valve 5 on the exhaust valve 7 side
A mask wall 2 that covers the opening of the air supply valve 5 for a period when the air supply valve 5 is fully open.
3 is formed on the inner wall surface of the cylinder radius 3.

Therefore, when the intake valve 5 opens, fresh air is supplied from the intake boat 6 into the combustion chamber 4 through the opening of the intake valve 5 on the opposite side to the exhaust valve 7. As a result, the fresh air flows along the peripheral wall surface of the combustion chamber 40 as shown by arrow S, thus achieving good loop scavenging.

Each air blast valve 9 is connected to an electronic control unit 5 shown in FIG.
It is controlled based on the output signal of 0. This electronic control unit 50 is interconnected by a bidirectional bus 51.
OM (read-on memory) 52 and RAM (random access memory) 53.1! :, CPU (microprocessor) 54, input port 55, and output port 56
Equipped with. The air flow meter 14 generates an output voltage proportional to the amount of intake air, and this output voltage is sent to the AD converter 57.
The input port 55 is manually inputted via the input port 55 . 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.
The output voltage is input to the input port 55 via the AD converter 59.

Further, a reference position sensor 61 and a crank angle sensor 62 are attached to the IJ computer 60. The reference position sensor 61 generates a reference signal G when the No. 1 cylinder reaches 5 degrees after top dead center, and this reference signal G is sent to the input port 55.
is input. On the other hand, the crank angle sensor 62 generates an output pulse every time the crankshaft rotates 30 degrees, and this output pulse is input to the input port 55. Furthermore, the activation signal of the starter switch 63 is input to the input port 55 . On the other hand, the output boat 56 has a corresponding drive circuit 64
．． 65 to the solenoid 37 of each air blast valve 9 and the fuel injection valve 41.

Next, control of the air blast valve 9 will be explained with reference to FIG. Note that FIG. 6 shows a case where the ignition order is 1-4-2-3, and therefore, the crank angles of each cylinder are shifted by 90 degrees according to this ignition order.

Referring to FIG. 6, as mentioned above, the reference signal G is generated at 5 degrees after the top dead center (360'' CA) of No. 1 cylinder #1.On the other hand, the 30 degree signal generated by the crank angle sensor 62 is generated at the crank angle. It is generated accurately based on 0° (=360°).When the 30° signal is generated first after the reference signal G is generated, it is determined that this time is 30° after the top dead center of No. 1 cylinder #1. The crank angle position of the gold cylinder is determined based on this.

As shown in Fig. 6, the crank angle is 1 after the starter switch is turned on until the reference signal G is generated.
The opening/closing valve 3 of the air blast valve 9 of two cylinders shifted by 80 degrees, in the embodiment shown in FIG. 6, the first cylinder #1 and the second cylinder #2.
3, that is, the air blast valve A1 of the first cylinder #1 and the air blast valve A2 of the second cylinder #2 are opened. Fifth
As can be seen from the figure, in the case of two cylinders whose crank angles are 180 degrees apart, when the intake valve 5 and exhaust valve 7 of one cylinder are open and the inside of the combustion chamber 4 is at almost atmospheric pressure, the pressure of the other cylinder is The intake valve 5 and the exhaust valve 7 are closed and the combustion chamber 4 is closed.
air is in a compressed state. Now, assuming that the intake valve 5 and exhaust valve 7 of the No. 1 cylinder #1 are closed, the air in the combustion chamber 4 of the No. 1 cylinder #1 is in a compressed state, so in this case The compressed air in the combustion chamber 4 of the first cylinder #1 is connected to the compressed air passage 31.39 in the air blast valve AI.
The compressed air is fed into the compressed air distribution chamber 20 through the compressed air distribution chamber 20. As a result, the compressed air pressure within the compressed air distribution chamber 20 increases. When the compressed air pressure in the compressed air distribution chamber 20 increases in this way, this compressed air flows out into the combustion chamber 4 of the second cylinder #2 via the air blast valve A2. However, the first cylinder #
The pressure difference between the compressed air pressure in the combustion chamber 4 of No. 1 and the compressed air pressure in the compressed air distribution chamber 20 is the pressure difference between the compressed air pressure in the combustion chamber 4 of No. 2 cylinder #2 and the compressed air pressure in the compressed air distribution chamber 20. will be considerably larger than. 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 the same as the amount of compressed air sent from the inside of the compressed air distribution chamber 20 to the combustion chamber 4 of the second cylinder #2.
The amount of compressed air flowing out into the chamber 20 is greater than the amount of compressed air flowing into the chamber 20, thus increasing the compressed air pressure within the compressed air distribution chamber 20.

In this way, the compressed air pressure in the compressed air distribution chamber 20 is increased between when the starter switch is turned on and when the reference signal G is generated.

On the other hand, when the reference signal G is generated, the crank angle of each cylinder can be determined. Therefore, at this time, the air blast valve 9 of each cylinder is opened from about 60 degrees before top dead center to about 60 degrees after top dead center, as shown by K in FIG. In the embodiment shown in FIG. 6, this is repeated three times. That is, as shown in FIG. 6, when the reference signal G is generated, the air blast valve A4 of the No. 4 cylinder #4 is first opened, and the compressed air in the combustion chamber 4 of the No. 4 cylinder #4 is compressed air. It is sent into the distribution chamber 20, and then the air blast valve A of the second cylinder #2
2 is opened and the compressed air in the combustion chamber 4 of the second cylinder #2 is sent into the compressed air distribution chamber 20, and then the air blast valve A3 of the third cylinder #3 is opened and the air blast valve A3 of the third cylinder #3 is opened. The compressed air in the combustion chamber 4 of cylinder #3 is transferred to the compressed air distribution chamber 20.
sent inside. As a result, the compressed air pressure within the compressed air distribution chamber 20 gradually increases.

Next, when a certain crank angle has elapsed after the reference signal G is 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, fuel is first 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 exhaust valve 7
Around the time when the air blast valve 2A closes, the air blast valve 2A is opened and fuel is injected together with compressed air into the combustion chamber 4 of the second cylinder #2. Then, compressed air is injected together with fuel from the air blast valve 9 of each cylinder in sequence according to the ignition order.

Next, when the engine starts self-driving operation, the air supply pump 18
In order to increase the discharge amount of
rises to.

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

Referring to FIG. 7, first, in step 100, it is determined 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. T! When the temperature is -40° C., step 101 proceeds and it is determined whether the starter switch 63 is on. When the starter switch 63 is on, the process proceeds to step 102, where it is determined whether a flag is set. When the starter switch 63 is turned on, the flag is reset, so the process proceeds to step 103. In step 103, the air blast valve A1 of the first cylinder #1 is opened. Next, in step 104, the second cylinder #
The second air blast valve A2 is opened.

Next, when the reference signal G is generated and the flag is set, the process proceeds from step 102 to step 105, where the air blast valve A1 of the first cylinder #1 is closed, and then, in step 106, the air blast valve A1 of the second cylinder #2 is closed. A2 valve is closed. Next, in step 107, the fourth cylinder #4
Data to open the air blast valve A4 between 60 degrees before top dead center and 60 degrees after top dead center is output to the output port 56, and then in step 108, 60 degrees before top dead center of No. 2 cylinder #2. Data to open the air blast valve A4 between 60° and 60° after top dead center is output to the output port 56, and then in step 109, from 60° before top dead center of No. 3 cylinder #3 to 60° after top dead center. The data for opening the air blast valve 3 between 60 degrees is output to the output port 56.

Note 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 it is considered that the compressed air pressure in the compressed air distribution chamber 20 is sufficiently high. Therefore, in this case, the processing routine is immediately completed, and the air blast valve A1 from step 103 to step 109. A2. A3°A4 valve opening processing is not performed.

FIG. 9 shows a fuel injection processing routine, which is executed at every fixed crank angle, for example every 90 degrees. The embodiment shown in FIG. 9 has timings shown by chain lines in FIG. 6 (90° CA, 180° CA).

270°CA, 360°CA). Incidentally, 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, in step 200, it is determined whether the engine cooling water temperature T is higher than 40°C. When T is 40° C., the process proceeds to step 201, where the crank angle θ from the generation of the reference signal G to the present is the constant rank angle θ shown in FIG. , that is, it is determined whether or not the angle exceeds 230°. θ Ku θ.

If so, the processing routine is completed. On the other hand, θ2
θ. If so, the process proceeds to step 202, where 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. Then step 203
Then, data for injecting fuel from the fuel injection valve 41 of the cylinder to be injected next, in the embodiment shown in FIG. 6, the fuel injection valve 41 of the second cylinder #2 is outputted to the output port 56. Next, in step 204, data for opening the air blast valve 9 of the cylinder to which fuel is injected from the fuel injection valve 41 at the regular valve opening timing P is outputted to the output port 56. In this way, fuel is injected together with compressed air from the air blast valve 9, and the engine is started.

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

Note that the present invention can also be applied to a six-cylinder two-stroke engine or a two-stroke engine with more cylinders. For example, if the present invention is applied to a 6-cylinder, 2-stroke internal combustion engine with an ignition order of 1-6-2-4-3-5, the crank angle will increase from the time the starter switch 63 is turned on until the reference signal G is generated. For example, the air blast valves of the first and fourth cylinders, which are shifted by 180 degrees, are opened.

〔Effect of the invention〕

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

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the invention, Fig. 2 is an overall view of the two-stroke internal combustion engine, Fig. 3 is a plan view of the two-stroke internal combustion engine shown in Fig. 2, and Fig. 4 is an enlarged side sectional view of the air blast valve. , 5th
The figure is a line diagram showing the opening period of the intake and exhaust valves, the opening period of the air blast valve, etc., Fig. 6 is a time chart showing the opening timing of the air blast valve in a 4-cylinder 2-stroke engine, etc., and Fig. 7 is a diagram showing the opening period of the air blast valve, etc. FIG. 8 is a flowchart showing a starting processing routine, FIG. 8 is a flowchart showing an interrupt routine based on a reference signal, and FIG. 9 is a flowchart showing an injection processing routine. 9... Air blast valve, 20... Compressed air distribution chamber, 32... Nozzle port, 41... Fuel injection valve, 18... Air supply pump, 31.39... Compressed air passage, 33...Opening/closing valve, 63...Starter switch.

Claims (1)

[Claims] An air blast valve is provided for each cylinder, which includes a nozzle port, a compressed air passage leading to the nozzle port, an on-off valve that controls the opening and closing of the nozzle port, and a fuel injection valve that injects fuel into the compressed air passage. A 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 into the compressed air distribution chamber by an engine-driven air supply pump, and a nozzle port of each air blast valve is connected to the compressed air passage of each air blast valve. a starter switch; a reference signal generating means for generating a reference signal indicating that any particular cylinder is at a particular crank angle; and a starter switch. A fuel for a two-stroke internal combustion engine, which is equipped with an on-off valve opening means for opening the on-off valves of air blast valves of two cylinders whose crank angles are shifted by 180 degrees between when the engine is turned on and the reference signal is generated. Injection control device.