JP3059561B2 - Engine intake control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake control device for an engine, and more particularly to an intake control device for an engine that increases the amount of air supplied to a combustion chamber under predetermined conditions.

[0002]

2. Description of the Related Art In an engine for a vehicle or the like, for the purpose of mainly improving the fuel efficiency at a low load, as shown in, for example, Japanese Patent Application Laid-Open No. 2-61181, a fuel exposed to a combustion chamber is provided. There is an injection valve that injects fuel with assist air. According to this, the rich portion of the fuel is unevenly distributed in the combustion chamber, and the air-fuel mixture is stratified. If the rich portion of the air-fuel mixture is ignited, the flame generated at that time is generated. Propagation to the surrounding lean mixture will result in good combustion properties with less fuel.

[0003]

On the other hand, in the engine, for the purpose of stabilizing the engine speed mainly during idling operation, for example, a bypass passage for bypassing the upstream and downstream of a throttle valve is provided in an intake system of the engine. There is a configuration in which the amount of air supplied to the combustion chamber is increased by correcting the opening degree of a control valve installed in a passage under a predetermined condition. When the intake air amount is corrected near the throttle valve in this way, a response delay occurs due to the volume of the intake passage reaching the combustion chamber,
A problem arises in terms of control accuracy.

To solve such a problem, it is conceivable to directly supply the increased air to the combustion chamber. In this case, for example, when the supply of the increased air is started after fuel injection, the fuel is diffused over a wide range. As a result, stratification of the air-fuel mixture may be hindered.

The present invention provides air assist means for supplying assist air to a fuel injection valve facing the combustion chamber through an air assist passage, and air increasing means for increasing the amount of air supplied to the combustion chamber under predetermined conditions. It is an object of the present invention to solve the above-mentioned problem in an engine provided with the above, and to supply increased air directly into a combustion chamber without obstructing stratification of an air-fuel mixture.

[0006]

According to a first aspect of the present invention, there is provided an intake control apparatus for an engine, which comprises an air assist means for supplying assist air to a fuel injection valve facing a combustion chamber via an air assist passage. Equipped in the low load range
Fuel supplied from the fuel injection valve and supplied from the air assist
Form a stratified mixture in the combustion chamber with the supplied air
And an engine provided with an air increasing means for increasing the air supplied to the combustion chamber when the auxiliary machine operates, wherein the air increasing means is configured to supply the increased air directly to the combustion chamber. At the same time, the introduction of the increased air into the combustion chamber prior to the fuel injected from the fuel injection valve is started, and the control means for activating the air increasing means so as to stop the introduction of the increased air before a predetermined period of the fuel injection. It is characterized by having been provided.

According to a second aspect of the present invention, in the engine intake control device according to the first aspect, the increased air by the air increasing means is introduced into the combustion chamber through the air assist passage and the fuel injection valve. It is characterized by having comprised in.

[0008]

According to the first aspect of the present invention, the increased air is introduced into the combustion chamber prior to the fuel injected from the fuel injection valve, and the introduction of the increased air is stopped before a predetermined period of the fuel injection. Therefore, the mixture is surely stratified.

According to the second aspect of the present invention, since the increased air is introduced into the combustion chamber via the air assist passage and the fuel injection valve, a device for supplying the increased air to the combustion chamber is specially provided. There is no need to provide it, which simplifies the configuration of the engine.

[0010]

Embodiments of the present invention will be described below.

As shown in FIG. 1, an engine 1 according to the embodiment is a known rotary piston engine, and includes a rotor housing 2 having a trochoidal inner peripheral surface formed therein,
It has a trochoid space defined by side housings 3 disposed on both sides of the trochoid space, and a substantially triangular rotor 5 supported by an eccentric shaft 4 rotates in the trochoid space in a clockwise direction in FIG. It is configured to exercise.

The side housing 3 is formed with an intake port 6 whose one end is open facing the trochoid space, and an intake passage 7 is connected to the other end of the intake port 6. An air flow sensor 8 for detecting the amount of intake air and a throttle valve 9 for adjusting the amount of intake air or the engine output are installed in the intake passage 7 from the upstream side.

On the other hand, the rotor housing 2 has an exhaust port 10 open at one end facing the trochoid space, and a pair of spark plugs 1 whose leading end ignition portions face the trochoid space.
1 _1, 11 ₂ and are disposed.

The rotor 5 supported on the eccentric shaft 4
Rotor flank 5 ₁ , 5 ₂ , 5 formed on the outer peripheral surface of
₃ sequentially form working chambers 12... 12 for performing intake, compression, combustion, and exhaust as the rotor 5 rotates.

[0015] Then, in this embodiment, the fuel injection port 13 that communicates with the working chamber 12 of the wall of the compression stroke of the side housing 3 close to the spark plug 11 ₁ of the trailing side
The fuel injection port 13 and the first fuel injection valve 14 are connected via an injection passage 15, and the air assist passage 16 connected to the intake passage 7 on the upstream side of the throttle valve 9. Are connected to the first fuel injection valve 14. An air pump 17 driven by the engine 1 and an air pump 17
Control valve 1 for adjusting the flow rate of pressurized air sent from
8 are provided.

A second fuel injection valve 19 is provided in the intake passage 8 at a position near the intake port 7.

In addition to the above configuration, the engine 1 is provided with an electronic control type control unit (hereinafter referred to as an ECU) 20. The ECU 20 represents an intake air amount signal from the air flow sensor 8 and a representative engine load. A throttle opening signal from a throttle sensor 21 for detecting a throttle opening to be detected and an engine speed signal from a rotation sensor 22 for detecting an engine speed are input, and the first and second signals are determined based on these signals. Fuel injection valve 14, 1
9 and control of the assist air amount by operating the air control valve 18 on the air assist passage 16.

Here, the first and second fuel injection valves 14,
To explain the 19 used space in the engine rotational speed N _E and the throttle opening θ are small low-speed low-load region (A), the fuel only from the first fuel injection valve 14 is adapted to be injected . At that time, the air control valve 18 is opened to promote the vaporization and atomization of the fuel. In addition, EC
When U20 determines that the predetermined air increase condition is satisfied, such as when the air conditioner switch is turned on, the U20 passes through the air assist passage 16 for a predetermined period prior to the fuel injection from the first fuel injection valve 14. An ON signal is output to the air control valve 18 so that the assist air is increased.

On the other hand, in the high rotation and high load region (B) other than the low rotation and low load region (A), the second fuel injection valve 1 is mainly used.
9 is used, and the first fuel injection valve 1 is used to enhance ignitability.
4 is used in an auxiliary manner.

Next, the fuel supply control performed by the ECU 20 in the low-speed low-load region (A) will be described.
This fuel supply control is performed as follows according to the flowchart of FIG.

That is, the ECU 20 determines whether or not a predetermined condition for increasing the amount of air is satisfied in step S1, and performs normal injection control when the determination is NO.
That is, the ECU 20 turns on the air control valve 18 to supply assist air for promoting fuel atomization in step S2.
After outputting the signal at a predetermined timing, an ON signal is output to the first fuel injection valve 14 at a predetermined timing in step S3.

On the other hand, when the ECU 20 determines in step S1 that the air increasing condition is satisfied, the ECU 20 proceeds to step S4 to supply the increased air to the air control valve 18 at a predetermined timing prior to the fuel injection. An ON signal is output, and an OFF signal is output to the air control valve 18 in step S5 after a predetermined time has elapsed. At a predetermined timing after a predetermined time has elapsed since the air control valve 18 was turned off, an ON signal is supplied to the air control valve 18 in order to supply assist air for promoting fuel atomization, similarly to the above steps S2 and S3. Is output to the first fuel injection valve 14 at a predetermined timing (steps S6 and S7).

Next, the operation of this embodiment will be described.

When the ECU 20 determines that the operation state of the engine belongs to the low-speed and low-load region (A) and does not satisfy the predetermined condition for increasing the amount of air, the ECU 20 performs the normal operation as shown in FIG. For example, 15 before compression top dead center
At a time t ₁ corresponding to 0 °, an ON signal is started to be output to the air control valve 18 and the state is maintained for 4 ms. And
At time t ₂ corresponding to some time elapsed before the compression top dead center 145 ° were from the operation of the air control valve 18 starts begins outputting an ON signal to the first fuel injection valve 14, is maintained during the state of 3ms . Therefore, fuel and air are injected in a mixed state from the fuel injection port 13 opened in the side housing 3, and the fuel is locally rich near the ignition plugs 11 ₁ and 11 _2. As a rich mixture is formed,
The area around which the fuel is relatively lean is formed in layers.

On the other hand, when the ECU 20 determines that the operating state of the engine 1 belongs to the low-rotation low-load region (A) and that the engine 1 is in the air increasing operation satisfying the predetermined air increasing condition, as shown in FIG. An ON signal is started to be output to the air control valve 18 at a time t ₃ corresponding to, for example, 270 ° before the compression top dead center for increasing air, and the operation of the air control valve 18 is started at a time t ₄ when ₃ ms has elapsed from the time t _3. Stop temporarily.
Then, for fuel mixing, for example, one before compression top dead center
At time t ₅ corresponding to 50 °, an ON signal is started to be output to the air control valve 18, and the state is maintained for 4 ms.
At time t _6, corresponding to some time elapsed before the compression top dead center 145 ° were from the operation of the air control valve 18 starts for the second time begins outputting an ON signal to the first fuel injection valve 14, the state 3.
Hold for 2 ms. As a result, air is introduced into the working chamber for a relatively long time, and the amount of intake air is increased. In this case, since the increasing air is injected prior to the fuel injection and is stopped before the start of the fuel injection, the stratification of the air-fuel mixture formed by the fuel injected from the first fuel injection valve 14 is performed. Conversion is not impaired.

In particular, in this embodiment, since the increased air is injected into the working chamber by using the air assist passage 16 communicating with the first fuel injection valve 14, an air supply system for increasing the amount of air is separately provided. There is an advantage that the configuration of the engine 1 is simplified as compared with the case of providing.

[0027]

As described above, according to the present invention, the increased air is introduced into the combustion chamber prior to the fuel injected from the fuel injection valve, and the introduction of the increased air is stopped before a predetermined period of the fuel injection. Therefore, the mixture is surely stratified.

In particular, according to the second aspect of the present invention, since the increased air is introduced into the combustion chamber through the air assist passage and the fuel injection valve, a device for supplying the increased air to the combustion chamber is specially provided. Need not be provided, thereby simplifying the configuration of the engine.

[Brief description of the drawings]

FIG. 1 is a control system diagram of an engine.

FIG. 2 is an engine operating area diagram for fuel injection control.

FIG. 3 is a flowchart illustrating fuel supply control in a low-speed low-load region of the engine.

FIG. 4 is a time chart showing a supply state of fuel and air during a normal operation.

FIG. 5 is a time chart showing a supply state of fuel and air when the amount of air is increased.

[Explanation of symbols]

 Reference Signs List 1 engine 12 working chamber 14 first fuel injection valve 16 air assist passage 18 air control valve 20 ECU

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02M 39/00-71/04 F02D 41/00-41/40

Claims (2)

(57) [Claims] An air assist means for supplying assist air to a fuel injection valve facing an combustion chamber through an air assist passage is provided. The fuel injection valve is supplied from the fuel injection valve in a low load region.
Combustion with the fuel supplied and the air supplied from the air assist means
The system is configured to form a stratified mixture in the room,
An air intake control device for an engine having an air increasing means for increasing air supplied to a combustion chamber when an auxiliary machine is operated , wherein the air increasing means is configured to directly supply increased air to the combustion chamber. In addition, the control for operating the air increasing means so that the introduction of the increased air is started into the combustion chamber prior to the fuel injected from the fuel injection valve and the introduction of the increased air is stopped before a predetermined period of the fuel injection. An intake control device for an engine, characterized by comprising means. 2. An intake air control system for an engine according to claim 1, wherein the increased air by the air increasing means is introduced into the combustion chamber via an air assist passage and a fuel injection valve. .