JPH06221170A - Air intake device for engine - Google Patents

Abstract

PURPOSE:To effectively properly use pressure air so as to meet a demand, such as stratification during low load running and improvement of charging efficiency during high load running, in an air intake device formed such that a fuel-air mixture generating port having a fuel injection valve and a timing valve is connected to a pressure air source through a pressure air feed passage. CONSTITUTION:Intake air ports 3 and 4 and a fuel-air mixture generating port 7 are provided and the fuel-air mixture generating port 7 is provided with a fuel injection valve 25 and a timing valve 15. The fuel-air mixture generating port 7 is connected to a pressure air feed passage 30, and a communicating part 33 through which the intake air ports 3 and 4 are communicated with the pressure air feed passage 30 is provided. The communicating part 33 is designed to be closed by an on-off valve 34 during low load running and opened thereby during high load ruining.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an engine, which is provided with a mixture forming port for mixing pressurized air and fuel and supplying the mixture to a combustion chamber, separately from the intake port.

[0002]

2. Description of the Related Art Conventionally, as shown in, for example, Japanese Utility Model Laid-Open No. 62-18335, in addition to first and second intake ports for supplying air to a combustion chamber, a third intake port for forming a mixture is provided. It is opened in the combustion chamber, a fuel injection valve is provided in this port, and this port is connected to a pressurized air supply passage equipped with a supercharger for supplying pressurized air, and this port has an opening to the combustion chamber. An intake device is known in which a timing valve (third intake valve) that opens and closes at a fixed timing is provided, and its opening timing is set to be later than the opening timing of the intake valves of the first and second intake ports. ing. In this device, the fuel and the pressurized air are mixed in the third intake port, and the mixture is burned in the latter half of the intake stroke, separately from the air taken in from the first intake port and the like. Sent to the room. Particularly in the low load region, while the second intake port is closed by the swirl control valve, swirl is generated in the combustion chamber by the intake air from the first intake port, while the air-fuel mixture is discharged from the third intake port in the central part of the combustion chamber. It is sent toward the spark plug. In this way, it is expected that the air-fuel mixture will be unevenly distributed around the spark plug, and that lean burn will reduce fuel consumption and improve emissions.

[0003]

By the way, in such an apparatus, in order to favorably achieve stratification at a low load, it is necessary to prevent the air-fuel mixture flowing into the combustion chamber from being dispersed.
It is necessary to control the flow of intake air at the intake port to some extent and to send the air-fuel mixture into the combustion chamber using pressurized air, while at the time of high load, use pressurized air to achieve stratification. Is unnecessary, and it is required to make the mixture uniform and improve the filling efficiency. However, in the above-described conventional device, the pressurized air supply system merely sends the pressurized air to the third intake port, so that the pressurized air is sufficiently and effectively utilized when the load is high. There wasn't.

In view of the above circumstances, the present invention makes it possible to effectively use pressurized air so that pressurized air can be selectively used so as to meet requirements such as stratification under low load and improvement of filling efficiency under high load. The purpose is to provide.

[0005]

According to a first aspect of the present invention, an intake port is provided for each cylinder of an engine, and an air-fuel mixture forming port connected to a pressurized air source via a pressurized air supply passage. An intake device for an engine provided with a fuel injection valve for injecting fuel into the mixture forming port and a timing valve for opening the mixture forming port with respect to the combustion chamber between the latter half of the intake stroke and the first half of the compression stroke. In the second aspect, a communication part that connects the intake port and the pressurized air supply passage is provided, and a communication part opening / closing means that closes the communication part at low load and opens at high load is provided.

A second aspect of the present invention is, for each cylinder of the engine, an intake port, a mixture forming port connected to a pressurized air source through a pressurized air supply passage, and an inside of the mixture forming port. In the intake device of the engine provided with a fuel injection valve for injecting and supplying fuel to the combustion chamber, and a timing valve for opening the mixture forming port with respect to the combustion chamber from the latter half of the intake stroke to the first half of the compression stroke, An intake port side fuel injection valve for injecting fuel at high load is provided, and an auxiliary air passage communicating with the pressurized air supply passage and having a downstream end reaching an injection position of the intake port side fuel injection valve is formed, Moreover, an opening / closing means is provided which closes the auxiliary air passage when the load is low and opens it when the load is high.

[0007]

According to the first aspect of the present invention, the pressurized air is supplied to the air-fuel mixture forming port when the load is low, and the air-fuel mixture of the fuel and the pressurized air burns from the air-fuel mixture forming port during the opening period of the timing valve. Pressurized air is utilized to atomize the fuel and stratify the air-fuel mixture at low loads, thus being fed into the chamber. On the other hand, when the load is high, pressurized air is sent to the intake port and used to increase the amount of intake air charged.

According to the second aspect of the invention, the action of supplying the compressed air to the mixture forming port at the time of low load is the same as that of the first aspect. On the other hand, at the time of high load, fuel is injected from the intake port side fuel injection valve in order to make the air-fuel mixture in the combustion chamber uniform, and at the same time, the above-mentioned addition as assist air to the fuel injected from the intake port side fuel injection valve is performed. Compressed air is used.

[0009]

Embodiments of the present invention will be described with reference to the drawings.
1 to 3 show an intake device according to a first embodiment of the present invention. In these figures, each cylinder 1 of the engine is provided with a combustion chamber 2 whose volume changes with the operation of a piston (not shown).
Intake ports 3 and 4 and first and second exhaust ports 5 and 6
And a mixture forming port 7 are provided. Further, an ignition plug 8 is provided at a substantially central portion of the combustion chamber 2.

The intake ports 3 and 4 are formed from one side of the cylinder head 9 to the combustion chamber 2, and the downstream end of each intake port is located at the intake side half of the combustion chamber 2 (the left half in FIG. 1). Both of the exhaust ports 5 and 6 are open from the other side of the cylinder head 9 to the combustion chamber 2, and the upstream end of each exhaust port is the exhaust side half of the combustion chamber 2 (right half in FIG. 1). Part).

The mixture forming port 7 is located between the intake ports 3 and 4 and opens into the combustion chamber 2 at a position close to the spark plug 8.

First and second intake valves 11 and 12 are provided at the openings of the first and second intake ports 3 and 4 to the combustion chamber 2, respectively, and the first and second exhaust ports 5 and 6 are connected. First and second exhaust valves 13 and 14 are provided at the openings to the combustion chamber 2, respectively. These intake valves 11 and 12 and exhaust valve 1
The valves 3 and 14 are operated by a valve mechanism (not shown) including a camshaft and the like. Further, a timing valve 15 is provided at the opening of the mixture forming port 7 to the combustion chamber 2, and the timing valve 15 opens the mixture forming port 7 between the latter half of the intake stroke and the first half of the compression stroke. Has become. That is, the timing valve 15 is opened and closed later than the intake valves 11 and 12, and is opened, for example, in a period of 90 ° after the top dead center to 90 ° after the bottom dead center at the crank angle.

Air is introduced into the intake ports 3 and 4 through the intake passage 16. The intake passage 16 includes a common intake passage 17 on the upstream side and a surge tank 18 on the downstream side.
And an independent intake passage 1 for each cylinder formed downstream thereof
9, and intake ports 3 and 4 are formed on the downstream side of each independent intake passage 19. The common intake passage 17 is provided with a throttle valve 20 that operates according to an accelerator operation to adjust the intake air amount.

The first intake port 3 of the two intake ports is formed so as to open in the circumferential direction of the combustion chamber 2 and generate swirl in the combustion chamber 2. The first intake port 3 is provided with an intake port side fuel injection valve 21 for injecting fuel into the port 3.

On the other hand, the second intake port 4 is provided with a swirl control valve 22 for opening and closing the second intake port 4, and the smaller the opening of the swirl control valve 22, the stronger the swirl. The swirl control valve 22 is actuated by an actuator (not shown) according to the engine load, etc., and is closed on the low load side of a predetermined load and opened on the high load side as the load increases.

The mixture forming port 7 is connected to an air pump 31 as a pressurizing source via a pressurized air supply passage 30, and a pressure regulator 32 is provided in the pressurized air supply passage 30. Has been done.

A mixture injection port side fuel injection valve 25 for injecting fuel into the port 7 is provided upstream of the timing valve 15 in the mixture formation port 7. Further, the fuel injection valve 2 in the mixture forming port 7
5, a throttle valve 26 that regulates the flow of the pressurized air
Is provided. The opening of the throttle valve 26 is changed by the throttle valve operating means 27 that operates according to the control signal.

Further, with respect to the pressurized air supply passage 30,
A communication portion that connects the passage 30 and the intake ports 3 and 4 is provided. In the example shown in FIG. 1, the communication portion 33 is provided between the surge tank 18 that communicates with the intake ports 3 and 4 and the pressurized air supply passage 30. Are formed. That is, in a state where the pressurized air supply passage 30 is adjacent to the surge tank 18 via the partition wall, the mixture forming port 7 of each cylinder 1 is connected to the pressurized air supply passage 30 and the communicating portion is connected to the partition wall. 33 is provided. The communication part 33 is provided with an opening / closing valve 34 as a communication part opening / closing means. This on-off valve 34 is an on-off valve operating means 3 that operates in response to a control signal.
It is designed to be opened and closed by 5.

Each of the fuel injection valves 21 and 25 and the throttle valve 26
A control unit (ECU) 36 for controlling the on-off valve 34 and the on-off valve 34 is provided. This EC
U36 is composed of a microcomputer or the like, receives signals from a rotation speed sensor 37 that detects an engine rotation speed, an engine load sensor 38 that detects an engine load equivalent amount such as an axial torque of the engine, and detects them by these signals. The fuel injection valves 21, 2 are
The control of fuel injection from the valve 5, the control of the opening degree of the throttle valve 26, and the control of the opening / closing of the opening / closing valve 34 are performed.

Fuel injection valves 21, 2 by the ECU 36
In the control of No. 5, in the low load region where the engine load is lower than the predetermined load, fuel injection is performed only from the fuel mixture formation port side fuel injection valve 25. Further, in the region on the higher load side than the predetermined load, fuel injection is also performed from the intake port side fuel injection valve 21, and the injection amount of the intake port side fuel injection valve 21 is increased and the air-fuel mixture is increased as the load increases. The injection amount of the fuel injection valve 25 on the formation port side is reduced. Such an injection amount map is stored in the ECU 36 in advance, and the injection amounts of the fuel injection valves 21 and 25 are controlled based on this map.

The control of the throttle valve 26 by the ECU 36 is such that the opening degree of the throttle valve 26 is minimized in the idling region and the low speed and low load region in the vicinity thereof, and the throttle valve 26 is increased as the engine speed and the engine load increase. The opening of is gradually increased. A map of the throttle valve opening degree according to such an operating state is also stored in the ECU 36 in advance, and the throttle valve 26 is controlled based on the comparison between the operating state detected by the sensors 37 and 38 and the map. Has become.

As for the control of the on-off valve 34 by the ECU 36, as shown in FIG. 3, the on-off valve 34 is closed in the low load side region (including the low speed medium load region) A and the output is increased. In the high load area B as required, the opening / closing valve 34 is opened. A map of the on-off valve control area is also stored in the ECU 36 in advance, and the on-off valve 34 is closed or opened depending on which of the areas A and B the operating state detected by the sensors 37 and 38 is. It is controlled.

According to the intake device of the present embodiment as described above, the open / close valve 34 of the communicating portion 33 is closed and the pressurized air from the air pump 31 is sent to the mixture forming port 7 during the low load operation. Further, the fuel is injected and supplied from the fuel injection valve 25 on the air-fuel mixture forming port side.

In this state, while the timing valve 15 is open, while the pressurized air and the fuel are mixed in the mixture forming port 7, the mixture flows into the combustion chamber 2 and the spark plug 8 Supplied to the vicinity. And the throttle valve 26
By restricting the subsequent flow of the pressurized air, the penetration force is appropriately adjusted, and the air-fuel mixture that has flowed into the combustion chamber 2 remains near the ignition plug 8. Therefore, the atomization of the fuel is promoted by the mixing with the pressurized air in the mixture forming port 7, the stratification is achieved, and the lean combustion is favorably performed. In this case, when the swirl control valve 22 is closed, the swirl is generated by the intake air from the first intake port 3, and the combustibility in the stratified state is further enhanced.

During high load operation, the communication section 33 is
The opening / closing valve 34 is opened, and the pressurized air from the air pump 31 is sent to the intake ports 3 and 4 through the surge tank 18, so that the pressurized air is used to increase the intake air charge amount. That is, at the time of high load operation, the fuel injection amount from the intake port side fuel injection valve 21 is increased and the swirl control valve 22 of the second intake port 4 is opened, so that the air-fuel mixture in the combustion chamber 2 becomes uniform. Is promoted and the inflow of intake air is promoted. At this time, it is not necessary to supply pressurized air to the mixture forming port 7 for stratification. Therefore, at this time, the pressurized air is supplied to the combustion chamber 2 from the intake ports 3 and 4 having a smaller flow resistance than the mixture supply port 7, and the intake charge amount is increased.

FIG. 4 shows a second embodiment of the present invention. Also in this embodiment, the first and second intake ports 3, 4
And a fuel-air mixture forming port 7 connected to a pressurized air source (not shown) via a pressurized air supply passage 30, a fuel injection valve 25 is provided in the fuel-air mixture forming port 7, and the first intake air The structure in which the intake port side fuel injection valve 21 for injecting fuel at the time of high load is provided in the port 3 is similar to that of the first embodiment. The difference from the first embodiment is that an auxiliary air passage 41 and an opening / closing valve 42 are provided as follows.

That is, the auxiliary air passage 41 communicates with the pressurized air supply passage 30, and the downstream end thereof reaches the injection position of the intake port side fuel injection valve 21. Further, the opening / closing valve 42 as an opening / closing means provided in the auxiliary air passage 41 is controlled by a control means (not shown) according to the operating state, so that the auxiliary air passage 41 is closed when the load is low and the auxiliary air passage 41 is closed when the load is high. It is supposed to open 41.

According to this embodiment, when the load is low, the auxiliary air passage 41 is closed and the pressurized air is sent to the air-fuel mixture supply port 7, so that the fuel atomization is performed by the same operation as in the first embodiment. And stratification is achieved. Further, when the load is high, the auxiliary air passage 41 is opened, and the pressurized air is sent to the injection position of the intake port side fuel injection valve 21 through the auxiliary passage 41, so that the intake port side fuel injection is performed as assist air. Promotes atomization of fuel from valve 21. Further, the pressurized air is sent into the combustion chamber through the air intake port 3 and also serves to increase the filling amount.

[0029]

According to the first aspect of the present invention, the mixture forming port provided separately from the intake port is provided with the fuel injection valve and the timing valve, and the mixture forming port is pressurized through the pressurized air supply passage. In the intake device connected to the air source, a communication part that connects the intake port and the pressurized air supply passage is provided, and this communication part is closed at low load and opened at high load, so fuel is supplied at low load. While satisfactorily achieving atomization and stratification, the pressurized air provided therefor can be effectively used to increase the intake charge amount at high load. Therefore, it is possible to effectively use the pressurized air properly so as to improve the fuel consumption under a low load and increase the torque under a high load.

In the second aspect of the invention, the fuel injection valve and the timing valve are provided in the mixture forming port connected to the pressurized air source via the pressurized air supply passage, while the intake passage is filled with the fuel at the time of high load. A fuel injection valve for injection and supply is provided, and an auxiliary air passage communicating with the pressurized air supply passage and having a downstream end reaching the injection position of the intake port side fuel injection valve is formed, and the auxiliary air passage is closed when the load is low. Since it opens at high load, pressurized air given for stratification at low load can also be used as assist air for fuel injected from the intake port side fuel injection valve at high load. It is possible to effectively use the pressurized air properly.

[Brief description of drawings]

FIG. 1 is an overall schematic plan view of an intake device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the intake device.

FIG. 3 is an explanatory diagram showing a region setting for control of an on-off valve that opens and closes a communication section.

FIG. 4 is a perspective view of a main part of an intake device according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Cylinder 3,4 Intake port 7 Mixture formation port 15 Timing valve 21 Intake port side fuel injection valve 25 Mixture formation port side fuel injection valve 30 Pressurized air supply passage 31 Air pump 33 Communication part 34 Open / close valve 41 Auxiliary air passage 42 Open / close valve

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication location F02D 13/02 L 7049-3G H 7049-3G F02M 69/00 360 B 7825-3G (72) Invention Noo Yoshihisa 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Mazda Motor Corporation

Claims (2)

[Claims] 1. An intake port, an air-fuel mixture forming port connected to a pressurized air source via a pressurized air supply passage, and fuel injected into the air-fuel mixture forming port for each cylinder of the engine. In an intake system for an engine provided with a fuel injection valve to be supplied and a timing valve for opening the mixture forming port with respect to the combustion chamber during the latter half of the intake stroke to the first half of the compression stroke, the intake port and the pressurized air are provided. An intake device for an engine, comprising: a communication part that communicates with the supply passage; and a communication part opening / closing means that closes the communication part when the load is low and opens the communication part when the load is high. 2. An intake port, an air-fuel mixture forming port connected to a pressurized air source through a pressurized air supply passage, and fuel injected into the air-fuel mixture forming port for each cylinder of the engine. In an intake system of an engine provided with a fuel injection valve to be supplied and a timing valve for opening the mixture forming port with respect to the combustion chamber during the latter half of the intake stroke to the first half of the compression stroke, the intake port is provided with a high load. An intake port-side fuel injection valve for injecting and supplying fuel is provided, and an auxiliary air passage communicating with the pressurized air supply passage and having a downstream end reaching an injection position of the intake port-side fuel injection valve is formed,
An intake device for an engine, further comprising opening / closing means for closing the auxiliary air passage at a low load and opening the auxiliary air passage at a high load.