JP2002339771A - Air-fuel mixture injection system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make high-pressure air cheaply for air-fuel mixture injection without adding an extra pressurizing means such as an air pump. SOLUTION: In a multiple cylinder engine 1, a combustion chamber of a specified cylinder #4 communicates with respective combustion chambers of other cylinders #1-#3, and compressed air obtained by stopping injection of fuel into the specified cylinder is utilized as the high-pressure air for the air-fuel mixture injection. An accumulating passage 11 extending from the combustion chamber of the specified cylinder is connected to a common rail 14 connected to an air-fuel mixture chamber of an air-fuel mixture injection valve 5. A poppet valve 12 is placed at an opening of the accumulating passage 11 to open and close according to operating condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air-fuel mixture injection system for an internal combustion engine, and more particularly, to the formation of high-pressure air that is premixed with fuel in the system before the air-fuel mixture is injected into a combustion chamber.

[0002]

2. Description of the Related Art An internal combustion engine provided with a fuel / air mixture injection means for injecting a fuel / air mixture in advance into a combustion chamber by mixing fuel and air in which fuel vaporization has been promoted has conventionally been disclosed in Japanese Patent Laid-Open No. 5-2 / 1993.
There is one disclosed in Japanese Patent No. 56230. In this apparatus, a fuel / gas mixing device for injecting a mixture of fuel and air under pressure into a combustion chamber is attached.
A fuel injection valve is connected to one end of the mixing device to supply fuel. Then, air is introduced into the common passage with the fuel, and a mixture of the fuel and the air is formed. The air-fuel mixture is injected into the combustion chamber via an operating valve provided at the end of the passage.

[0003]

However, in order to inject the air-fuel mixture formed using such air-fuel mixture injection means in the compression stroke, it is necessary to use high-pressure air as the air mixed with the fuel. . Therefore, there is a problem that an air pump or the like is required to pressurize the air, resulting in an increase in cost.

Therefore, the present invention utilizes the existing engine configuration without adding a special pressurizing means such as an air pump to high-pressure air which is premixed with fuel before the fuel-air mixture is injected into the combustion chamber. It is an object of the present invention to provide a mixture injection system for an internal combustion engine which can be formed at low cost. Also,
An object of the present invention is to provide control means according to the operating state of an internal combustion engine provided with such a mixture injection system.

[0005]

For this reason, an air-fuel mixture injection system for an internal combustion engine according to the first aspect of the present invention includes an internal combustion engine having a plurality of cylinders. And a combustion chamber of at least one cylinder other than the specific cylinder and a combustion chamber of a target cylinder to which a fuel-air mixture is to be injected, and a fuel-air mixture chamber formed in the communication passage. A fuel injection valve for injecting fuel into the air-fuel mixture chamber, a first on-off valve for opening and closing the communication passage between the combustion chamber of the specific cylinder and the air-fuel mixture chamber, and a fuel-air mixture in the air-fuel mixture chamber. A second on-off valve for opening and closing an injection port for injecting the fuel into the combustion chamber of the target cylinder; and stopping the fuel supply to the specific cylinder and performing the first on-off operation in a predetermined operating state in which the mixture is to be injected. While opening the valve at the prescribed operating time, Outside the operating state, configured to include a control means for remains closed the first on-off valve.

According to a second aspect of the present invention, there is provided an air-fuel mixture injection system for an internal combustion engine, wherein one side of the air-fuel mixture chamber between the first on-off valve and the air-fuel mixture chamber is provided in the communication passage.
A storage pressure chamber having a sufficiently large capacity as compared with the air-fuel mixture chamber is formed. An air-fuel mixture injection system for an internal combustion engine according to the invention according to claim 3, wherein a flow from the storage chamber to the air-fuel mixture chamber is provided between the storage chamber and the air-fuel mixture chamber in the communication passage. It is characterized in that an allowable first check valve is provided.

According to a fourth aspect of the present invention, there is provided an air-fuel mixture injection system for an internal combustion engine, wherein one side of the communication passage is provided between the first on-off valve and the air-fuel mixture chamber on the side of the first on-off valve. And a second check valve that allows a flow from the combustion chamber of the specific cylinder to the mixture chamber. An air-fuel mixture injection system for an internal combustion engine according to claim 5, wherein each of the specific cylinder and the target cylinder is provided with fuel supply means separately from the fuel injection valve, and an operating state other than the predetermined operating state , Wherein the control means controls the another fuel supply means to supply fuel to each cylinder.

According to a sixth aspect of the present invention, in the fuel / air mixture injection system for an internal combustion engine, the control means may include a controller for controlling the operation of the air-fuel mixture from when the operating state shifts from an operating state other than the predetermined operating state to the predetermined operating state. In the transition period, the fuel supply to the target cylinder by the another fuel supply unit is continued, and after the transition period has elapsed, the fuel supply is stopped and the second on-off valve is controlled to control the mixture chamber. Characterized by injecting an air-fuel mixture.

According to a seventh aspect of the present invention, there is provided an air-fuel mixture injection system for an internal combustion engine, further comprising a detecting means for detecting a pressure in the air-fuel mixture chamber or a pressure in the communication passage associated therewith. When the pressure becomes equal to or higher than a predetermined operation permission pressure, the end of the transition period is determined. In the fuel-air mixture injection system for an internal combustion engine according to the invention of claim 8, the control means is configured to, after the transition period has elapsed, start from when the pressure is less than a predetermined appropriate pressure range and exceed the appropriate pressure range. The first on-off valve is opened at the operation timings up to and the first on-off valve is kept closed at other non-operation timings.

According to a ninth aspect of the present invention, in the fuel / air mixture injection system for an internal combustion engine, the control means keeps the intake valve of the specific cylinder open during the non-operation timing. In the fuel-air mixture injection system for an internal combustion engine according to the invention of claim 10, the control means keeps the first on-off valve closed during the transition period from the transition of the operating state to a predetermined timing. It is characterized by the following.

According to an eleventh aspect of the present invention, in the fuel-air mixture injection system for an internal combustion engine, the predetermined time is a time until the combustion products remaining in the combustion chamber of the specific cylinder are scavenged. Features. A mixture injection system for an internal combustion engine according to a twelfth aspect of the present invention includes a detection unit provided in an exhaust passage of the specific cylinder, the detection unit detecting a concentration of a combustion product contained in exhaust gas, and the control unit Is
The predetermined time is determined based on a detection signal from the detection means.

[0012]

According to the first aspect of the present invention, in a predetermined operating state in which the mixture is to be injected, the specific cylinder is
Since the fuel supply is stopped, an air pump for discharging the intake air as it is is configured. Therefore, by opening the first on-off valve in such an operating state, the pressurized air formed in the specific cylinder is sent into the air-fuel mixture chamber. And
The fed compressed air mixes with the fuel injected from the fuel injection valve to form an air-fuel mixture.

As described above, according to the present invention, the high-pressure air premixed with the fuel before the fuel-air mixture injection can be formed by using a part of the cylinders constituting the internal combustion engine as an air pump. Therefore, it is not necessary to add any special pressurizing means, and the mixture can be injected at a low cost. According to the second aspect of the present invention, the pressure of the high-pressure air supplied into the air-fuel mixture chamber can be maintained by the storage chamber provided in front of the air-fuel mixture chamber.

According to the third aspect of the present invention, air can be stably supplied into the air-fuel mixture chamber by the first check valve provided between the pressure storage chamber and the air-fuel mixture chamber. Claim 4
According to the invention described in (1), the second check valve provided between the first on-off valve and the air-fuel mixture chamber eliminates the need for the operation of the first on-off valve according to the engine rotation. For this reason, control of the first on-off valve can be simplified.

According to the fifth aspect of the invention, power can be obtained from either the specific cylinder or the target cylinder in an operating state other than the predetermined operating state. Therefore, it is possible to cope with, for example, a high-load operation state in which a sufficient output cannot be obtained by the mixture injection. According to the invention described in claim 6, the fuel supply to the target cylinder is continued during the transition period of the operating state, so that when the mixture is injected, the high-pressure air supplied to the mixture chamber is formed. By the time the power can be maintained.

According to the invention described in claim 7, it is possible to secure a sufficient period for boosting pressure for forming high-pressure air after the transition of the operating state. According to the eighth aspect of the present invention, the pressure of the air supplied into the air-fuel mixture chamber can be easily controlled within an appropriate pressure range when the air-fuel mixture is injected. According to the ninth aspect of the present invention, the intake valve is kept open at the time when the first on-off valve is not operated during the mixture injection, so that unnecessary compression of the intake air can be avoided.
Energy loss can be reduced.

According to the tenth aspect, the fuel supply to the specific cylinder is stopped and the first on-off valve is kept closed from the transition of the operating state to a predetermined time in the transition period. Therefore, during this time, the cylinder can be scavenged. According to the eleventh aspect, the supply of the pressurized air to the air-fuel mixture chamber is started after the scavenging of the combustion products, so that the combustion products are prevented from adhering to the inner wall of the communication passage, the valve, and the like. Can be.

According to the twelfth aspect, the completion of scavenging of the combustion products can be easily determined as the predetermined time at which the supply of the compressed air is started.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of an engine 1 including a mixture injection system according to an embodiment of the present invention. Here, a four-cylinder engine will be described as an example.
As long as a plurality of cylinders are provided, the present invention can be applied to any multi-cylinder engine such as a two-cylinder engine and a six-cylinder engine.

In this example, the fourth cylinder is selected as the specific cylinder, and the other first to third cylinders are selected as the target cylinders. According to the present invention, the specific cylinder may be any other cylinder, and is not limited to one, and a plurality of cylinders may be selected as the specific cylinder.
In the engine 1, the configuration of the first to third cylinders is as follows.

In these cylinders, a fuel injection valve 3 facing the intake passage 2 and an air-fuel mixture injection valve 5 facing substantially the upper center of the combustion chamber 4 are provided. The fuel injection valve 3 installed in the intake passage 2 injects fuel toward the port. The injected fuel is introduced into the combustion chamber 4 under the control of the intake valve 6 together with the intake air taken into the intake passage 2 to form a homogeneous mixture.

On the other hand, the air-fuel mixture injection valve 5 forms the air-fuel mixture in a stratified form by directly injecting the air-fuel mixture formed beforehand into the combustion chamber 4 in the compression stroke, as described later. is there. Fuel injection valve 3 and mixture injection valve 5
Is used depending on the operation state, and operates based on a control signal from an electronic control unit (ECU) 31.

In addition, other reference numerals 7 indicate an exhaust passage, 8
Is an exhaust valve for opening and closing the exhaust passage with respect to the combustion chamber 4, and 9 is a piston. Although not shown, the intake valves 6 and the exhaust valves 8 provided in the first to third cylinders may be of a mechanical drive type using a cam or the like, or may be an electromagnetic drive type using a solenoid or the like. On the other hand, the configuration of the fourth cylinder is as follows.

The fuel injection valve 3 is provided in the intake passage 2 as described above. The fuel injection valve 3 also operates based on a control signal from the ECU 31 to form a homogeneous mixture in the combustion chamber 4. In the fourth cylinder, a mixture injection valve is not provided, and a third passage (storage passage) other than the intake passage 2 and the exhaust passage 7 is used as a passage facing the combustion chamber 4 and forming an opening. ) 11 are provided.

A poppet valve (storage passage valve) 12 as a first opening / closing valve is provided at the opening of the storage passage 11, and the storage pressure passage 11 is opened and closed with respect to the combustion chamber 4 by this valve 12. You. The storage pressure passage valve 12 is controlled by a solenoid-type driving device 13 that receives a control signal from the ECU 31, opens at a predetermined operation timing described later, and supplies compressed air in the combustion chamber 4 (in the cylinder) to the storage pressure passage. Release to 11.

The storage pressure passage 11 is connected to a common air passage (common rail) 14 for the first to third cylinders, and an air distribution passage 15 extends from the passage 14 so that high-pressure air is supplied to each of the mixture injection valves 5. Sent to. Here, the common rail 14 is formed to have a sufficiently large capacity as compared with the air-fuel mixture chamber inside the air-fuel mixture injection valve 5 and constitutes a pressure storage chamber as a pressure storage unit.

As is clear from the above description, the communication passage between the specific cylinder and the target cylinder according to the present invention is the storage pressure passage 1
1. It includes a common rail (storage chamber) 14, an air distribution passage 15, and an air-fuel mixture chamber inside the mixed intake injection valve 5. Other symbols in the communication passage allow 16 to flow from the combustion chamber 4 of the fourth cylinder toward the common rail 14,
A first check valve 17 shuts off the opposite flow. A second check valve 17 allows the flow from the common rail 14 toward the air-fuel mixture chamber of each air-fuel mixture injection valve 5 and shuts off the opposite flow. is there.

The detection signals input to the ECU 31 include an accelerator opening detection signal from an accelerator opening sensor 41 and an engine speed detection signal from a crank angle sensor 42 (corresponding to a reference crank angle signal or a unit crank angle signal). ), The common rail internal pressure detection signal from the pressure sensor 43 installed facing the internal space of the common rail 14, and the HC installed facing the exhaust passage 7 of the fourth cylinder.
The HC concentration detection signal from the (hydrocarbon) concentration sensor is included.

[0029] The ECU 31 uses these detection signals to determine
A control signal is generated for the fuel injection valve 3, the air-fuel mixture injection valve 5, and the storage pressure passage valve driving device 13. In addition, the 4th
Control signals are generated for an intake valve driving device 18 and an exhaust valve driving device 19 provided in the cylinder. FIG. 2 is a cross-sectional view of the air-fuel mixture injection valve 5 provided in the first to third cylinders in the present embodiment. The structure of the air-fuel mixture injection valve 5 will be briefly described with reference to FIG.

The mixture injection valve 5 has a mixture chamber 52 formed inside a main body 51. The air-fuel mixture chamber 52 communicates with the common rail 14 via the air introduction hole 53 and the air distribution passage 15 and communicates with the combustion chamber 4 (the lower surface of the cylinder head is indicated by a dashed line 4w) via the injection port I. .
A fuel injection valve 54 for injecting an air-fuel mixture other than the fuel injection valve 3 described above is provided facing the air-fuel mixture chamber 52.
Fuel is supplied to the fuel injection valve 54 by the fuel pump P via a fuel supply passage 55. Note that reference numeral 56 is
This is a connector for electrical connection with the ECU 31.

Accordingly, pressurized air is sent from the common rail 14 into the air-fuel mixture chamber 52, and fuel is injected and supplied by the fuel injection valve 54. Then, before the formed air-fuel mixture is injected into the combustion chamber 4 through the injection port I, the vaporization of the fuel is promoted. A needle valve 57 as a second opening / closing valve is provided at the injection port I, and this valve element is opened by exciting an electromagnetic solenoid 58 based on a control signal from the ECU 31. ECU 31
Excites the solenoid 58 in the compression stroke of the first to third cylinders, and a stratified mixture is formed in the combustion chamber 4 of the cylinder.

Next, the control contents of the ECU 31 will be described with reference to the flowcharts of FIGS. FIG.
It is a flowchart of an operation mode selection routine. S
In (step) 1, it is determined whether or not the current operation state is in the homogeneous combustion operation region. For this reason, the ECU 31
The engine speed Ne and the accelerator opening APO are read, and for example, it is determined that the engine is in the homogeneous combustion operation region in the high rotation and high load operation state.

If it is determined that the current operation state is in the homogeneous combustion operation region, the process proceeds to S2, and the operation mode is set to the homogeneous operation mode. In the homogeneous operation mode, port injection is performed by operating the fuel injection valves 3 of the first to fourth cylinders, and a uniform mixture is formed in the combustion chamber 4 to perform homogeneous combustion. In this mode, output performance equivalent to that of a general homogeneous combustion engine is obtained.

If it is determined in S1 that the current operation state is not in the homogeneous combustion operation region, the process proceeds to S3, and it is determined whether scavenging of the fourth cylinder is necessary. In an operation region other than the homogeneous combustion operation region, the engine 1 performs stratified combustion. At this time, the mixture injection valves 5 of the first to third cylinders are operated, and the fourth cylinder functions as an air pump for supplying high-pressure air to the mixture injection valves 5. Before performing such control, it is S3 that determines whether or not the fourth cylinder is in a state where it can be used as an air pump.

That is, if combustion products remain in the combustion chamber 4 of the fourth cylinder, the combustion products are sent into the common rail 14 together with the compressed air, and the passage is blocked and the valve operates. It causes the first time. If a filter is provided in the storage passage 11, such a problem is temporarily solved, but the filter is clogged at an early stage.
Therefore, while combustion products remain in the combustion chamber 4,
A decision is made to prohibit use as an air pump. Specifically, when the detection signal from the HC concentration sensor 44 is larger than a predetermined value (exhaust gas from the fourth cylinder contains unburned fuel), scavenging of the fourth cylinder is necessary. to decide. As another method, it is determined whether or not the accumulated engine speed か ら Ne after the operating state shifts out of the homogeneous combustion operation range is equal to or less than a predetermined value, or the elapsed time after the shift is within a predetermined time. Can be determined.

If it is determined in S3 that scavenging of the fourth cylinder is necessary, the process proceeds to S4, and the operation mode is set to the scavenging operation mode. In the scavenging operation mode, the fuel injection valves 3 of the first to third cylinders are operated to continuously perform homogeneous combustion in these cylinders. In the fourth cylinder, combustion products in the combustion chamber 4 are scavenged to the exhaust passage. Operation is performed.

If it is determined in S3 that scavenging of the fourth cylinder is not necessary, the process proceeds to S5, where the air pressure Prail in the common rail 14 is reduced to the operation permission pressure Pin of the mixture injection valve 5.
It is determined whether it is smaller than j. When the air pressure Prail is smaller than the operation permission pressure Pinj, the process proceeds to S6, and the operation mode is set to the storage pressure operation mode.

In the storage pressure operation mode, the fuel injection valves 3 of the first to third cylinders are operated to perform homogeneous combustion in these cylinders. The sending operation is performed. When it is determined in S5 that the air pressure Prail is equal to or higher than the operation permission pressure Pinj, the process proceeds to S7, and the operation mode is set to the stratified operation mode.

In the stratified operation mode, stratified charge combustion is performed in the first to third cylinders by injection of the air-fuel mixture from the air-fuel mixture injection valve 5, and compressed air obtained in the compression stroke is sent to the common rail 14 in the fourth cylinder. Driving is performed.
The period from when it is determined in S1 that the operating state is not in the homogeneous combustion operation region to when it is determined in S5 that the air pressure Prail is equal to or higher than the operation permission pressure Pinj is from
This corresponds to the “operating state transition period” according to the present invention.

Next, control of each device according to the operation mode set as described above will be described. FIG.
5 is a flowchart of a control routine for the fuel injection valves 3 installed in the intake passages 2 of the first to fourth cylinders. If it is determined in S11 that the operation mode is the homogeneous operation mode, S1
Proceeding to 2, the fuel injection valves 3 in all the first to fourth cylinders are caused to perform fuel injection at a predetermined timing. Thereby, homogeneous combustion is performed in each combustion chamber 4.

If the operation mode is the scavenging operation mode (S13) or the storage pressure operation mode (S14), the process proceeds to S15.
Fuel injection is stopped only for the fourth cylinder. And
In S16, the corresponding fuel injection valve 3 is operated at a predetermined timing in order to continue the homogeneous combustion for the remaining first to third cylinders. If the operation mode is the stratified operation mode,
Proceeding to S17, fuel injection is stopped for all of the first to fourth cylinders.

FIG. 5 is a flowchart of a control routine for the fuel-air mixture injection valve 5 installed facing the combustion chambers 4 of the first to third cylinders. If it is determined in S21 that the operation mode is the homogeneous operation mode, the process proceeds to S22, in which each of the mixture injection valves 5
To stop. In an operation mode other than the homogeneous operation mode, the engine is in an operation state in which stratified combustion by air-fuel mixture injection is to be performed. Is performed.

Therefore, if the operation mode is the scavenging operation mode (S23) or the storage pressure operation mode (S24), S
Proceeding to 22, the operation of the air-fuel mixture injection valve 5 is continuously stopped. In the storage pressure operation mode, the pressure in the common rail 14 is increased, and pressurized air is sent into the air-fuel mixture chamber 52. If the operation mode is the stratified operation mode, the process proceeds to S25, in which the mixture injection valves 5 of the first to third cylinders are operated at a predetermined timing during the compression stroke, and the vaporization of the fuel in the combustion chamber 4 is promoted. The mixture is injected.

FIG. 6 is a flow chart of a control routine of the storage pressure passage valve 12, which is a control valve for opening and closing the storage pressure passage 11, which communicates the combustion chamber 4 of the fourth cylinder with the common rail 14 as the storage pressure chamber. . If it is determined in S31 that the operation mode is the homogeneous operation mode, the process proceeds to S32, and the storage pressure passage valve 1
2 is closed.

In an operation mode other than the homogeneous operation mode, it is necessary to send compressed air into the common rail 14 to inject the air-fuel mixture. Here, the scavenging of the fourth cylinder is started from the transition of the operation state. Therefore, if it is determined in S33 that the operation state is the scavenging operation mode, the process proceeds to S34, and the storage pressure passage valve 12 is kept closed.

If it is determined in S35 that the operation mode is the accumulation mode, the process proceeds to S36, and the accumulation passage valve 12 is operated. In this embodiment, the check valve 16 is
Is installed. Therefore, compressed air is delivered only when the pressure in the combustion chamber 4 is higher than the pressure in the common rail 14. Conversely, even if the pressure in the common rail 14 becomes higher in the combustion chamber 4, no backflow occurs. Therefore, the storage pressure passage valve 12 does not need to be opened and closed according to the pressure in the combustion chamber 4, and may be kept open in this operation mode. However, in the case where the operation of the intake valve 6 and the exhaust valve 8 is hindered because the storage pressure passage valve 12 is always open, the valve is opened only during the compression stroke.

If the operation mode is the stratified operation mode, S
Proceeding to 37, the accumulator passage valve 12 is operated according to the flowchart shown in FIG. FIG. 7 shows the control of the intake valve 6 and the exhaust valve 8 in addition to the control of the storage pressure passage valve 12 in the stratified operation mode. In S41 shown in FIG. 7, it is determined whether or not the air pressure Prail in the common rail 14 is smaller than the lower limit value Pmin of the appropriate pressure range.

If it is determined that the air pressure Prail is smaller than the lower limit value Pmin, the process proceeds to S42, where the storage pressure passage valve 12 is operated to send compressed air into the common rail 14. Here, since the backflow from the common rail 14 is prevented by the check valve 16, the storage pressure passage valve 12 is always opened as described above unless the normal operation of other components is hindered.

At S43, the intake valve 6 and the exhaust valve 8 are set to operate normally. Air pressure P at S41
If it is determined that the rail is equal to or larger than the lower limit value Pmin, the process proceeds to S44, and it is determined whether or not this is greater than the upper limit value Pmax of the appropriate pressure range. Air pressure Pra
When it is determined that il is equal to or less than the upper limit value Pmax,
Returning this routine, the storage pressure passage valve 12 and the intake valve 6
And the control of the exhaust valve 8 is continued. That is, from the time when the air pressure Prail falls below the lower limit value Pmin to the time when it exceeds the upper limit value Pmax, the operation of the storage pressure passage valve 12 is continued, and the intake valve 6 and the exhaust valve 8 operate as usual.

At S44, the air pressure Prail is increased to the upper limit value Pm.
If it is determined that the pressure is larger than ax, the process proceeds to S45, where the storage pressure passage valve 12 is closed, and the delivery of the compressed air to the common rail 14 is stopped. At this time, unnecessary compression of the intake air is avoided by switching to a setting in which the intake valve 6 is kept open and the exhaust valve 8 is kept closed in the subsequent S46.

Next, when the air pressure Prail falls below the lower limit value Pmin, the operation of the storage pressure passage valve 12 is restarted, and the intake valve 6 and the exhaust valve 8 are returned to the normal operation. As described above, according to the present invention,
The high-pressure air supplied to the air-fuel mixture injection valve 5 can be formed by using a part of the cylinders constituting the internal combustion engine as an air pump. Therefore, it is not necessary to add any special pressurizing means, and the mixture can be injected at a low cost.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an engine 1 including a mixture injection system according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an air-fuel mixture injection valve constituting the same system.

FIG. 3 is a flowchart of an operation mode selection routine.

FIG. 4 is a flowchart of a control routine for a fuel injection valve 3 installed in an intake passage 2;

FIG. 5 is a flowchart of a control routine for a fuel-air mixture injection valve 5;

FIG. 6 is a flowchart of a control routine of the storage pressure passage valve 12.

FIG. 7 is a flowchart of a control routine for the storage pressure passage valve 12, the intake valve 6, and the exhaust valve 8 in the stratified operation mode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Intake passage 3 ... Fuel injection valve 5 ... Air-fuel mixture injection valve 51 ... Body 52 ... Air-fuel mixture chamber 54 ... Fuel injection valve 57 ... Needle valve 58 ... Electromagnetic solenoid 6 ... Intake valve 7 ... Exhaust passage 8 ... Exhaust Valve 11 ... storage pressure passage 12 ... storage pressure passage valve 13 ... storage pressure passage valve drive device 14 ... storage pressure chamber 15 ... air distribution passage 16, 17 ... check valve 31 ... electronic control unit 41 ... accelerator opening degree sensor 42 ... Crank angle sensor 43 ... Pressure sensor 44 ... HC concentration sensor

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) DF02 DF03 DF04 DF05 DF09 DG01 EA11 FA24 FA50 HA13Z HB03Z HB09Z

Claims (12)

[Claims] In an internal combustion engine having a plurality of cylinders, combustion of a combustion chamber of a specific cylinder among these cylinders, and combustion of at least one cylinder other than the specific cylinder, which is a target cylinder to which a mixture injection is performed, is performed. A communication passage that communicates with the chamber; a fuel-air mixture chamber formed in the communication passage; a fuel injection valve that injects fuel into the fuel-air mixture chamber; and a combustion chamber of the specific cylinder and the fuel-air mixture chamber. A first on-off valve for opening and closing the communication passage, a second on-off valve for opening and closing an injection port for injecting the air-fuel mixture in the air-fuel mixture chamber into the combustion chamber of the target cylinder, and performing the air-fuel mixture injection. In a predetermined operating state, control is performed to stop fuel supply to the specific cylinder and open the first on-off valve at a predetermined operation timing, while keeping the first on-off valve closed in other operating states. Means,
An air-fuel mixture injection system for an internal combustion engine comprising: 2. A pressure storage chamber having a capacity sufficiently larger than that of the air-fuel mixture chamber is formed on one side of the air-fuel mixture chamber between the first on-off valve and the air-fuel mixture chamber in the communication passage. The fuel-air mixture injection system according to claim 1, wherein: 3. A first check valve is provided in the communication passage between the storage chamber and the mixture chamber to allow a flow from the storage chamber to the mixture chamber. The mixture injection system for an internal combustion engine according to claim 2, wherein 4. A flow from the combustion chamber of the specific cylinder to the mixture chamber on one side of the communication path between the first on-off valve and the air-fuel mixture chamber on the side of the first on-off valve. The mixture injection system for an internal combustion engine according to any one of claims 1 to 3, further comprising an allowable second check valve. 5. A fuel supply device is provided for each of the specific cylinder and the target cylinder separately from the fuel injection valve. In an operation state other than the predetermined operation state, the control means controls the other fuel supply means. The mixture injection system for an internal combustion engine according to any one of claims 1 to 4, wherein fuel is supplied to each cylinder under control. 6. The fuel supply system according to claim 1, wherein the control unit is configured to control the other fuel supply unit to switch to the target cylinder during a transition period from a transition from an operation state other than the predetermined operation state to the predetermined operation state. The fuel supply is continued, and after the transition period elapses, the fuel supply is stopped, and the air-fuel mixture in the air-fuel mixture chamber is injected by controlling the second on-off valve. Mixture injection system for internal combustion engines. 7. A detecting means for detecting a pressure in the air-fuel mixture chamber or a pressure related to the pressure in the communication passage, wherein the control means detects when the pressure becomes equal to or higher than a predetermined operation permission pressure. 7. The mixture injection system for an internal combustion engine according to claim 6, wherein it is determined that the transition period has ended. 8. The control means according to claim 1, wherein, after the transition period has elapsed, the first operation is performed at an operation timing from when the pressure is less than a predetermined appropriate pressure range to when the pressure exceeds the appropriate pressure range.
8. The valve according to claim 7, wherein the on-off valve is opened, and the first on-off valve is kept closed at other non-operating times.
2. A mixture injection system for an internal combustion engine according to claim 1. 9. The mixture injection system for an internal combustion engine according to claim 8, wherein said control means keeps an intake valve of said specific cylinder open during said non-operation timing. 10. The control device according to claim 6, wherein said control means keeps said first on-off valve closed from the time of transition of said operating state to a predetermined time during said transition period. A mixture injection system for an internal combustion engine according to any one of the preceding claims. 11. The mixture injection system for an internal combustion engine according to claim 10, wherein the predetermined time is a time until the combustion products remaining in the combustion chamber of the specific cylinder are scavenged. . 12. An exhaust passage provided in said specific cylinder,
The apparatus according to claim 11, further comprising: a detecting unit configured to detect a concentration of a combustion product contained in the exhaust gas, wherein the control unit determines the predetermined time based on a detection signal from the detecting unit. A mixture injection system for an internal combustion engine according to claim 1.