JP2001304079A - Idle control valve device of engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the deterioration of idle controllability, to improve charging efficiency of an engine, and to improve engine output by surely eliminating a backflow of suction air via a bypass passage, and avoiding fouling by blow-by gas and EGR gas of an idle control valve interposed in the bypass passage. SOLUTION: An inlet side passage 20a of the bypass passage 20 is obliquely formed toward the idle control valve 21 from an inlet side passage opening part 20b to a throttle bore 15a in a throttle body 15. The throttle bore 15a is diametrally expansively formed by turning a part for positioning the inlet side passage opening part 20b of the bypass passage 20 toward the upstream side on the upstream side of a throttle valve 14. Thus, a venturi effect in the inlet side passage opening part 20a of the bypass passage 20 is surely eliminated to eliminate the backflow of the suction air via the bypass passage 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine idle control valve device for surely flowing intake air downstream without flowing back through a bypass passage of a throttle valve.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, an idle control valve 104 of an engine provided in a bypass passage 103 bypassing a throttle valve 102 of a throttle bore 101.
It is known that the inlet side passage 103a of the bypass passage 103 is provided substantially perpendicular to the opening 103b of the throttle bore 101 in the direction of the idle control valve 104.

Further, as is well known, the throttle valve 102
A blow-by gas passage and an EGR passage are connected to the downstream intake system, and the blow-by gas and the EGR gas are recirculated.

[0004] Therefore, particularly in the fully opened region of the throttle valve, as shown by a broken line in FIG.
The intake air containing gas flows back through the bypass passage 103,
Bypass passage 10 by blow-by gas or EGR gas
The idle control valve 104 interposed in 3 is soiled. As a result, the operation of the idle control valve may be hindered by contaminants adhering to the operating portion such as the rotating slider inside the idle control valve 104, and the idle controllability may be deteriorated. In addition, there is a disadvantage that the charging efficiency of the engine is deteriorated due to the backflow of the intake air through the bypass passage 103.

To cope with this, Japanese Patent Laid-Open Publication No. 2000-45
Japanese Patent Publication No. 914 discloses an idle control valve device in which an inlet-side passage of a bypass passage is formed obliquely in a downstream direction from an inlet-side passage opening of a throttle bore, so that intake and intake air flows smoothly.

[0006]

However, in this prior art, since the intake air flowing downstream of the throttle bore is not positively introduced into the inlet side passage of the bypass passage, blow-by gas or EGR gas is not introduced. Backflow through the bypass passage containing the intake air cannot be reliably prevented, and the idle controllability deteriorates due to contamination of the idle control valve by blow-by gas or EGR gas,
It is difficult to solve the problem of the deterioration of the charging efficiency of the engine due to the backflow of the intake air.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention reliably eliminates the backflow of intake air through a bypass passage, and provides blow-by gas or EG for an idle control valve interposed in the bypass passage.
It is an object of the present invention to provide an engine idle control valve device capable of avoiding contamination by R gas, eliminating deterioration of idle controllability, and improving engine charging efficiency and improving engine output.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, an inlet side passage of a bypass passage which bypasses a throttle valve disposed in a throttle bore through which intake air flows is provided by the throttle valve. In an idle control valve device for an engine formed obliquely in a downstream direction from an inlet-side passage opening of a bore, a portion of the throttle bore where the inlet-side passage opening is located is formed so that a diameter thereof is increased toward upstream. And

That is, according to the present invention, the portion of the throttle bore where the inlet-side passage opening of the bypass passage is located is increased in diameter toward the upstream, and the inlet-side passage is formed obliquely in the downstream direction. The venturi effect at the passage opening on the inlet side of the passage is reliably eliminated. This prevents intake air containing blow-by gas and EGR gas downstream of the throttle valve from flowing back through the bypass passage, avoids contamination of the idle control valve with blow-by gas and EGR gas, and eliminates deterioration of idle controllability. It is possible to do. Also, since the backflow of intake air through the bypass passage is eliminated, the charging efficiency of the engine is improved,
The output of the engine improves.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 relate to an embodiment of the present invention. FIG. 1 is an overall configuration diagram of an engine system, and FIG. 2 is a sectional explanatory view of a bypass passage portion of a throttle body.

In FIG. 1, reference numeral 1 denotes an engine,
In this embodiment, a horizontally opposed 6-cylinder engine is shown. A cylinder block 2 of the engine 1 is divided into two banks on both sides of a crankshaft. An intake port 4 and an exhaust port 5 are formed in a cylinder head 3 of each bank.

An intake manifold 6 is communicated with the intake port 4 of each cylinder, and the intake manifolds 6 of each cylinder for each bank are assembled and communicated with the intake chambers 7a and 7b. Furthermore, the intake chambers 7a, 7
A variable intake valve 8 driven to be opened and closed by an actuator 9 is interposed in a passage communicating with b.

The actuator 9 is connected to a negative pressure tank 11 which communicates with one of the intake chambers 7a via a one-way valve 10. A switching solenoid valve provided in a passage connecting the actuator 9 and the negative pressure tank 11 is provided. 1
2, the operating pressure introduced into the actuator 9 is switched between negative pressure and atmospheric pressure in accordance with the engine operating range.

The intake chamber 7 corresponding to each bank
a, 7b, passages 13a, 13b extend upstream from respective positions on both sides of the variable intake valve 8, and these passages 13a, 13b
a and 13b are gathered and communicated with a throttle body 15 in which a throttle valve 14 interlocked with an accelerator pedal is interposed, so that intake air is evenly distributed to each bank. An intake pipe 17 is connected to an upstream side of the throttle body 15 via an air chamber 16, and an air cleaner 18 is attached to an upstream side of the intake pipe 17. A chamber is provided in the middle of an air intake passage connected to the air cleaner 18. 19 is communicated.

A bypass passage 20 bypassing the throttle valve 14 is connected to the throttle body 15. An idle control valve 21 for controlling an idle speed is interposed in the bypass passage 20. The air flow rate in the bypass passage 20 is adjusted by the valve 21.

A spark plug 22 for exposing the discharge electrode portion to the combustion chamber is attached to each cylinder of the cylinder head 3, and an air assist is provided immediately upstream of the intake port 4 of each cylinder of the intake manifold 6. An injector 25 is provided. In the air assist injector 25,
Fuel is supplied via a fuel supply passage 27 extending from a fuel tank 26, and atomization of the injected fuel in a low rotation / low load region is performed via an air assist passage 28 extending from an idle control valve 21. Assist air for promotion is introduced.

An in-tank type fuel pump 30 is provided in the fuel tank 26, and the fuel from the fuel pump 30 is supplied to the air assist injector 25 through a fuel supply path 27.
The pressure is fed to the pressure regulator 31, the excess fuel is returned from the pressure regulator 31 to the fuel tank 26, and the fuel pressure of the fuel supply system to the air assist injector 25 is adjusted to a predetermined pressure.

Further, a first purge passage 32 extends from the upper portion of the fuel tank 26 to purge the fuel vapor generated in the fuel tank 26 into the intake system.
3, and is communicated with an upper portion of a canister 34 having an adsorbing portion made of activated carbon or the like. The canister 34 is provided at its lower part with a fresh air inlet communicating with the atmosphere, and a second purge for introducing a mixture (evaporative gas) of fresh air from the fresh air inlet and the evaporated fuel gas stored in the adsorption section. A passage 35 extends from the top.

The second purge passage 35 is provided with the throttle valve 1
4, passages 13 a, 13 b communicating from the throttle body 15 to the intake chambers 7 a, 7 b of each bank.
An opening is provided in the intake system at approximately the center and upstream of the branch portion 13c that branches to the intake system. In the middle of the second purge passage 35, a canister purge control (CPC) duty solenoid valve whose valve opening is controlled in accordance with the duty ratio of the drive signal in order to control the purge ratio of evaporated fuel to intake air. 36, and this CP
On the upstream side of the C-duty solenoid valve 36, a chamber 37 for silencing airflow noise and pulsation noise generated when the CPC duty solenoid valve 36 operates is provided.

On the other hand, the exhaust ports 5 of the cylinder head 3 of the engine 1 are gathered in the cylinder head 3 for each bank and communicated with the exhaust pipe 38, and the exhaust pipe 38 of each bank is provided.
In addition, a catalytic converter 39 containing a three-way catalyst is interposed, and a catalytic converter 40 also containing a three-way catalyst is interposed at a collecting portion of the exhaust pipe 38 of each bank, and a muffler 42 is provided via a silencer 41. Is communicated to.

Also, EG is supplied from the exhaust pipe 38 of one bank.
An R (exhaust gas recirculation) passage 43 extends, and passages 13a, 13 extending from intake chambers 7a, 7b of each bank.
3b. In the middle of the EGR passage 43, E
An EGR valve 44 for adjusting the GR amount is interposed, and a part of the exhaust gas is recirculated to the intake system according to the degree of opening of the EGR valve 44.

Although not shown, a well-known PCV valve for controlling the flow rate of blow-by gas when recirculating blow-by gas generated in the crankcase to the intake system is attached to the cylinder head 3 of one bank. A blow-by gas passage opening downstream of the throttle valve 14 is connected to the PCV valve.

The engine 1 is provided with sensors for detecting the engine operating state. That is, the throttle valve 1 interposed in the throttle body 15
4, the throttle opening sensor 50a and the throttle valve 14
A throttle sensor 50 having a built-in idle switch 50b that is turned on when fully closed is connected in series, and an intake pipe pressure sensor 51 that detects the intake pipe pressure downstream of the throttle valve 14 is provided downstream of the throttle valve 14. . The air chamber 16 has an intake air temperature sensor 52 for detecting the intake air temperature.
Is coming.

Further, a knock sensor 53 is attached to each bank of the cylinder block 2 of the engine 1, and a cooling water temperature sensor 55 faces a cooling water passage 54 formed in the cylinder block 2. A linear air-fuel ratio sensor 56 is disposed upstream of the catalytic converter 39 of the exhaust pipe 38 of each bank.
On the downstream side of the catalytic converter 40 interposed in the collecting portion of
An O2 sensor 57 is provided.

A crank angle sensor 5 is mounted on the outer periphery of a crank rotor 58 which is mounted on the crankshaft of the engine 1.
9 and a half with respect to the crankshaft.
A cylinder discriminating sensor 61 is provided opposite to a cam rotor 60 connected to a rotating camshaft.

The above engine 1 is electronically controlled by an electronic control unit (not shown). That is, the electronic control unit processes a detection signal from each sensor / switch, a battery voltage, and the like, and based on various data stored in a memory, various learning value data, fixed data, and the like, a fuel injection amount,
Calculate the ignition timing, the target idle speed, the target purge rate of the evaporative fuel, the target EGR rate, etc., and perform fuel injection control, ignition timing control, idle speed control, evaporative fuel purge control, EG
Engine control such as R control is performed.

Here, the configuration of the passage of the throttle body 15 will be described with reference to FIG. Throttle body 15
The throttle valve 14 is rotatably disposed in a throttle bore 15a through which intake air flows, and opens and closes the throttle bore 15a in conjunction with an accelerator pedal. Further, an idle control valve 21 is provided outside the throttle body 15, and an inlet side passage 20 of a bypass passage 20 which is formed in the throttle body 15 and bypasses the throttle valve 14.
a and the outlet side passage 20 c are connected to the idle control valve 21.

The inlet side passage 20a of the bypass passage 20 is
The throttle body 15 is formed obliquely from the inlet-side passage opening 20b to the throttle bore 15a toward the idle control valve 21, and the intake air flowing from the throttle bore 15a is smoothly introduced into the idle control valve 21.

The throttle bore 15a is formed by increasing the diameter of the upstream side of the throttle valve 14 toward the upstream side of the portion where the inlet-side passage opening 20b of the bypass passage 20 is located. The diameter is increased toward the downstream.

Therefore, when the throttle valve 14 is opened, as shown by a dashed line in FIG.
4 upstream, a part of the intake air in the throttle bore 15a is reliably introduced from the inlet-side passage opening 20b into the inlet-side passage 20a without any Venturi effect, and is circulated to the idle control valve 21.

On the other hand, the bypass passage 2 downstream of the throttle valve 14 is caused by the Venturi effect caused by the flow of the intake air.
0, the pressure in the outlet side passage 20c decreases. For this reason,
In the bypass passage 20, the direction of the air flow is changed from the inlet passage 20a to the outlet passage 2 through the idle control valve 21.
0c, the intake air containing blow-by gas or EGR gas downstream of the throttle valve 14 is reliably prevented from flowing back through the bypass passage 20, and the idle control valve 21 using blow-by gas or EGR gas is prevented. Is prevented, and deterioration of idle controllability is eliminated. Further, since the backflow of the intake air through the bypass passage 20 is eliminated, the charging efficiency of the engine 1 is improved, and the engine output is improved.

[0032]

As described above, according to the present invention, the backflow of the intake air through the idle control valve can be surely eliminated, and the blow-by gas and the EGR gas contained in the intake air downstream of the throttle valve can be eliminated. And the deterioration of the idle controllability can be eliminated. Further, by eliminating the backflow of the intake air via the idle control valve, the charging efficiency of the engine is improved, and the engine output can be improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an engine system.

FIG. 2 is an explanatory sectional view of a bypass passage portion of a throttle body.

FIG. 3 is an explanatory cross-sectional view of a bypass passage portion of a throttle body according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 14 Throttle valve 15 Throttle body 15a Throttle bore 20 Bypass passage 20a Inlet passage 20b Inlet passage opening 21 Idle control valve

Claims (1)

[Claims] An idle control of an engine wherein an inlet side passage of a bypass passage which bypasses a throttle valve disposed in a throttle bore through which intake air flows is formed obliquely in a downstream direction from an inlet side passage opening of the throttle bore. An idle control valve device for an engine, wherein a portion of the throttle bore, in which the inlet-side passage opening is located, is formed to have a diameter which is increased toward an upstream side.