JP2002047977A - Air suction controller of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air suction controller of an internal combustion engine capable of effectively performing combustion by swirl formed using a bypass passage, accurately controlling an amount of suction air when idling operation is done, and realizing stable idle condition. SOLUTION: This air suction controller of an internal combustion engine is provided with a throttle valve 9 of electronic control type arranged on an air suction passage 4 of the internal combustion engine 1 to adjust an amount of suction air, the bypass passage 11 which is provided so as to bypass the throttle valve 9 and whose downstream side end part 11a is connected with the vicinity of a suction valve 6 of a suction port 4b, a bypass air valve 20 adjusting an amount of air passing through the bypass passage 11, and a rich gas supply means 12 for supplying rich gas to a downstream side of the throttle valve 9 on the air suction passage. Upon completion of warming-up of the internal combustion engine 1, a part or all of suction air amount control when idling is done by the throttle valve 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake control system for an internal combustion engine for controlling an intake air amount of the internal combustion engine.

[0002]

2. Description of the Related Art A throttle valve disposed on an intake passage of an internal combustion engine for adjusting an intake air amount, a bypass passage provided to bypass the throttle valve, and an air amount passing through the bypass passage Japanese Patent Laid-Open Publication No.
The one described in JP-A-11-311140 is known. The bypass described in the above publication has a downstream end connected to the vicinity of the intake valve of the intake port (hereinafter, the downstream end of such a bypass is also referred to as a jet port). The intake control device disclosed in the above publication generates a swirl in a cylinder by providing a jet port,
An object is to enable effective combustion using swirl.

In addition, a vehicle driven by an internal combustion engine at present is provided with a rich gas supply means for supplying a rich gas to a downstream side of a throttle valve on an intake passage.
As such a rich gas supply means, there is a means for reducing blow-by gas blown from a combustion chamber into a crankcase (in Japan, a blow-by gas reduction device is required by law), and a method for removing evaporated fuel in a fuel tank. There is a purge on the intake passage. Such a rich gas is often supplied to a surge tank immediately before the intake passage is divided into intake ports for each cylinder.

[0004]

In the intake control device described in the above publication, the throttle valve is fully closed at the time of idling, so that the amount of intake air supplied to the combustion chamber is adjusted by the bypass air valve. But,
At this time, in the section from the throttle valve to the intake port, only the air leaking from the gap between the throttle valve and the intake pipe flows. For this reason, there is a problem that the rich gas supplied by the rich gas supply unit is not evenly distributed to each cylinder, and the air-fuel ratio of each cylinder varies.

[0005] If the air-fuel ratio varies among the cylinders, there is a concern that idle rotation becomes unstable and idle vibration becomes remarkable (leads to engine stall), or the exhaust gas purification rate during idling deteriorates. You. Accordingly, an object of the present invention is to provide an intake control device for an internal combustion engine that can effectively perform swirl combustion by a jet port, accurately perform intake air amount control during idling, and realize a stable idle state. To provide. To achieve a stable idle state by accurately controlling the intake air amount during idling, the throttle valve controls the intake air amount during idle operation after warm-up.
A stable idle state is realized by increasing the amount of intake air from the throttle valve and promoting the mixing of rich gas supplied on the intake passage.

[0006]

According to a first aspect of the present invention, there is provided an electronically controlled throttle valve disposed on an intake passage of an internal combustion engine for adjusting an intake air amount, and bypasses the throttle valve. A bypass passage, the downstream end of which is connected near the intake valve of the intake port, a bypass air valve for adjusting the amount of air passing through the bypass passage, and a rich gas downstream of the throttle valve on the intake passage. An intake control device for an internal combustion engine, comprising: a rich gas supply unit that supplies the intake air to the engine after the completion of warming-up of the internal combustion engine. I have.

According to a second aspect of the present invention, in the first aspect of the invention, when a part of the intake air amount control at the time of idling is performed by the throttle valve after the completion of the warm-up of the internal combustion engine, The required intake air amount of the engine is obtained as the sum of the various correction control amounts, and which of the various correction control amounts is shared by the throttle valve and which of the various correction control amounts is shared by the bypass air valve is the magnitude of the change amount of the various correction control amounts. Is determined based on

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described. FIG. 1 shows a configuration diagram of an internal combustion engine having the intake control device of the present embodiment.

The intake control device according to the present embodiment controls the amount of intake air of an engine 1 which is an internal combustion engine. As shown in FIG. 1, the engine 1 generates a driving force by igniting an air-fuel mixture in each cylinder 3 with a spark plug 2. When the engine 1 burns,
The air taken in from the outside passes through the intake passage 4 and is mixed with the fuel injected from the injector 5 and is taken into the cylinder 3 as a mixture. Inside of cylinder 3 and intake passage 4
Is opened and closed by the intake valve 6. The air-fuel mixture burned inside the cylinder 3 is exhausted to the exhaust passage 7 as exhaust gas. The interior of the cylinder 3 and the exhaust passage 7 are opened and closed by an exhaust valve 8.

An air cleaner and an air flow meter 13 for detecting the amount of intake air are also provided on the upstream side of the intake passage 4. Further, on the intake passage 4, a throttle valve 9 for adjusting the amount of intake air taken into the cylinder 3 is provided. The throttle valve 9 of the present embodiment is an electronically controlled throttle valve. The throttle valve 9 is connected to a throttle position sensor 10 for detecting the opening degree. The throttle valve 9 is connected to a throttle motor 22, and is opened and closed by a driving force of the throttle motor 22. The throttle motor 22 also has a function as a clutch that connects the accelerator pedal 23 and the throttle valve 9 when an abnormality occurs. An accelerator position sensor 24 for detecting the operation amount of an accelerator pedal (accelerator opening) is also provided near the throttle valve 9.

A bypass passage 11 that bypasses the throttle valve 9 extends parallel to a part of the intake passage 4.
Are arranged. A bypass air valve 2 for adjusting the amount of air passing through the bypass 11 is provided on the bypass 11.
0 is provided. The bypass air valve 20 is a rotary solenoid valve or a solenoid valve that opens and closes on and off. In the case of a rotary solenoid valve, the amount of passing air is adjusted by its opening, and in the case of a solenoid valve that opens and closes on and off, the amount of passing air is adjusted by an open / close duty ratio.

The downstream end of the bypass passage 11 is connected to the most downstream intake port 4 b of the intake passage 4. That is, the most downstream side of the bypass passage 11 is connected to the vicinity of the intake valve 6. This part is hereinafter referred to as a jet port 11a.
I will say it. As shown in FIG. 2, two intake ports 4 b of the present embodiment are provided for each cylinder 3, and the above-described jet port 11 a is one of the two intake ports 4 b of each cylinder. It is formed on one outside. For this reason, the air (air-fuel mixture) drawn into the cylinder 3 via the bypass passage 11 forms a swirl vortex in the cylinder 3.

Further, a surge tank 4a is formed downstream of the throttle valve 9. Intake passage 4
Is one at the portion where the throttle valve 9 is disposed, but is branched for each cylinder in the surge tank 4a. The above-mentioned bypass 11 is also branched in the middle thereof, and the downstream jet port 11a is connected to the intake port 4b of each cylinder 3 one by one.

The surge tank 4a is connected to one end of a recirculation path 12 for recirculating blow-by gas blown from the cylinder 3 into the crankcase.
The other end of the return path 12 is connected to a crankcase. Although a valve is not provided on the recirculation path 12 in FIG. 1, a valve may be provided to adjust the recirculation amount of the blow-by gas. In the present embodiment, the blow-by gas reduction mechanism functions as a rich gas supply unit that supplies the rich gas to the intake passage 4 on the downstream side of the throttle valve 9.

A crank position sensor 14 for detecting the position of the crankshaft is mounted near the crankshaft of the engine 1. From the output of the crank position sensor 14, the position of the piston 15 in the cylinder 3 and the engine speed NE can be obtained. The engine 1 is also provided with a knock sensor 16 for detecting knocking of the engine 1 and a water temperature sensor 17 for detecting a cooling water temperature.

These spark plugs 2, injectors 5,
Throttle motor 22, throttle position sensor 1
0, air flow meter 13, crank position sensor 1
4. Knock sensor 16, water temperature sensor 17, bypass air valve 20, accelerator position sensor 24, and other actuators and sensors are connected to an electronic control unit (ECU) 18 that comprehensively controls engine 1. These actuators and sensors are provided by the ECU 18
From the ECU 18 or the ECU 18
Is sent out the detection result.

The exhaust gas purifying catalyst 1 disposed on the exhaust passage 7
The catalyst temperature sensor 21 for measuring the temperature of the fuel cell 9 is also connected to the ECU 18. The ECU 18 also includes an upstream air-fuel ratio sensor 25 mounted upstream of the exhaust purification catalyst 19.
A downstream air-fuel ratio sensor 26 attached downstream of the exhaust purification catalyst 19 is also connected. Since the air-fuel ratio sensors 25 and 26 cannot perform accurate detection unless the temperature exceeds a predetermined temperature (activation temperature), the electric power supplied from the ECU 18 so that the temperature is quickly raised to the activation temperature. Temperature.

The ECU 18 includes a CPU for performing calculations therein, a RAM for storing various amounts of information such as calculation results, and a backup RA whose contents are held by a battery.
M, a ROM storing each control program, and the like. The ECU 18 performs intake air amount control by the throttle valve 9 and the bypass air valve 20, air-fuel ratio control, fuel injection amount control, and the like.

Next, control of the amount of intake air during idle speed control by the above-described intake control device will be described. The above-described engine 1 controls the idle speed by adjusting the intake air amount.

The intake control device of this embodiment is characterized by having an electronically controlled throttle valve 9 and a bypass 11 connected to the jet port 11a. Since the throttle valve 9 is of an electronic control type, the opening thereof can be arbitrarily controlled by the ECU 18. In addition, swirl can be effectively generated in the cylinder 3 by taking in air from the jet port 11 a using the bypass passage 11. The intake control by the throttle valve 9 and the intake control by the bypass passage 11 and the bypass air valve 20 can be optionally used / switched by the ECU 18.

In the intake control device of this embodiment, when the engine 1 is in an idle state immediately after a cold start, the intake air amount necessary for combustion in the cylinder 3 is controlled only by the intake control by the bypass passage 11 and the bypass air valve 20. Control. At this time, the throttle valve 9 is fully closed. In the idle state immediately after the cold start, the swirl is generated in the cylinder 3 by using the intake control by the bypass passage 11 and the bypass air valve 20 to promote the combustion.

As a result, the operation at the lean air-fuel ratio can be performed stably immediately after the cold start, and a stable idle state can be maintained, and the fuel efficiency can be improved. In addition, as a result, the retard limit of the ignition timing is expanded, and ignition can be performed at a more retarded side. By igniting on the retard side, the exhaust gas temperature can be raised,
By raising the temperature of the exhaust purification catalyst 19 earlier, the purification rate of the exhaust gas can be improved.

The rich gas supplied to the intake passage 4 by the rich gas supply means is supplied upstream of the jet port 11a. That is, the rich gas is supplied into the cylinder 3 by the air leaking from the throttle valve 9 in the fully closed state and the intake pipe negative pressure near the intake port 4b. The rich gas recirculated to the intake passage 4 such as a surge tank by the rich gas supply means (blow-by gas reduction mechanism) is easily mixed sufficiently if the intake air amount is large, but is difficult to mix if the intake air amount is small and distributed. Cause a defect.

When the warm-up is completed and the engine speed has settled to the predetermined idle speed, the amount of intake air becomes smaller than that immediately after the cold, and distribution failure is likely to occur. If the rich gas supplied to the intake passage 4 by the rich gas supply means is not accurately distributed to the cylinders 3 and a distribution failure occurs, the air-fuel ratio of each cylinder 3 varies and the idle state becomes unstable. Idle vibration becomes noticeable.

Therefore, in this embodiment, the bypass passage 11 and the jet port 1
The intake air is supplied to the cylinder 3 using 1a. When the warm-up of the engine 1 is completed, the intake air is gradually switched to the supply from the throttle valve 9 side. When the intake air is supplied from the throttle valve 9 side, the rich gas supplied to the intake passage 4 by the rich gas supply means is accurately supplied to each cylinder 3 by the intake air from the throttle valve 9 flowing from the upstream side. Distributed to Then, after the warm-up is completely completed, all of the intake air at the time of idling is supplied from the throttle valve 9. The reason why the intake air is gradually switched instead of switching to the supply from the throttle valve 9 side at a stretch is that if it is switched at a stretch, the intake control may be roughened.

By doing so, it is possible to improve the fuel efficiency and the purification rate of exhaust gas while realizing a stable idle state before the completion of the warm-up. A stable idling state can be realized without causing poor distribution of rich gas. FIG. 3 shows a flowchart of the control for performing this switching. Hereinafter, this control will be described with reference to FIG.

First, since the intake control here is for the idle state, it is determined whether or not the idling operation is being performed (step 100). If the engine is not in the idle state, the air is supplied from the throttle valve 9 side (or by using both the throttle valve 9 side and the bypass path 11 side) immediately after the cold start or after the warm-up is completed. Is supplied to the cylinder 3. If step 100 is denied, the control shown in the flowchart of FIG. 3 is temporarily terminated.

On the other hand, if step 100 is affirmed, it is next determined whether or not the warm-up operation has been completed (step 110). If the warming-up operation has not been completed, as described above, the intake air amount control is entirely performed using the bypass passage 11 and the bypass air valve 20 (step 18).
0). At this time, the throttle valve 9 is fully closed. If step 110 is affirmative, that is, if the warm-up operation has been completed, the intake control during idling is gradually shifted from control from the bypass passage 11 and the bypass air valve 20 to control on the throttle valve 9 side. It is determined whether or not the idle speed control sharing switching condition, which is a necessary condition for the idle speed control, is satisfied (step 12).
0).

The sharing switching condition includes various conditions for determining whether to switch the sharing between the intake from the bypass passage 11 and the bypass air valve 20 and the intake from the throttle valve 9 side. For example, whether or not the amount of time change of the intake air amount is small. If the sharing switching condition is affirmative, the above-described sharing switching is permitted.
That is, if step 120 is denied, even if the warm-up operation has been completed, the sharing is not switched, and the control shown in the flowchart of FIG. 3 is temporarily terminated.

On the other hand, if the result in step 120 is affirmative, the bypass air valve 2 is switched to switch the sharing.
It is determined whether the opening degree of 0 (previous value) is not in the fully closed state (step 130). Immediately after the switching is permitted, the opening degree (previous value) of the bypass air valve 20 is not zero. When step 130 is denied, that is, when the opening degree (previous value) of the bypass air valve 20 is zero (it was in the fully closed state), the above-described switching of sharing is completely shifted to the throttle valve 9 side. You can judge that you are doing. In this case, the intake air amount control is already performed on the throttle valve 9.
Side, the intake air amount control is entirely performed using the throttle valve 9 as it is (step 1).
70).

On the other hand, if step 130 is affirmative,
That is, when the opening degree (previous value) of the bypass air valve 20 is not zero (not in the fully closed state), it can be determined whether the above-described switching of the sharing has not started yet or is still in the middle of the switching. In this case, the bypass air valve 2
An opening degree of 0 (current value) is set to a value obtained by subtracting a predetermined change amount α for change from the previous value (step 140). Next, similarly, the opening degree (current value) of the throttle valve 9 is set to a value obtained by adding a predetermined switching gradual change amount β to the same (previous value) (step 150).

In this manner, at the time of the above-mentioned switching of the sharing, the opening of the bypass air valve 20 is closed by the switching gradual change amount α, and the opening of the throttle valve 9 is opened by the switching gradual change amount β. Then, based on the respective valve openings (current values) determined in steps 140 and 150, the intake control on the throttle valve 9 side and the intake control on the bypass air valve 20 side are used together to obtain the intake air during idling. Perform control (step 16
0).

Next, another embodiment of the present invention will be described. In the above-described embodiment, all of the intake air amount control at the time of idling after the completion of the warm-up is performed by the throttle valve 9. However, in this embodiment, a part of the intake air amount control at the time of idling after the warm-up is completed is performed by the throttle valve 9, and the rest is performed by the control of the bypass air valve 20. That is, in the present embodiment, the control of the intake air amount at the time of idling after the completion of warming-up uses both the control on the throttle valve 9 side and the control on the bypass air valve 20 side.

Hereinafter, the control of this embodiment will be described. The required intake air amount required by the engine 1 during idling in the present embodiment is determined by the following equation. "Idle control control amount = Flow learning value + Air-conditioner OFF feedback correction amount + Correction amount for target rotation change + Start-up correction amount + Water temperature correction amount + Catalyst warm-up correction amount + Rotational change correction amount + Air-conditioner correction amount + Alternator load Correction amount + Electric load correction amount + Power steering load correction amount + Dash pod correction amount + ND shift correction amount + Idle speed control correction amount by purge + Variable valve timing advance failure correction amount + Deceleration idle up correction amount + Cruise Control control amount "

The above-mentioned required intake air amount is calculated by the ECU 18 based on various information amounts. That is, engine 1
Is obtained as the sum of various correction control amounts. The flow rate learning value is a basic part of the required intake air amount, and is corrected by various correction amounts to calculate a final required intake air amount. The learning value of the flow rate is a learning value after performing learning for reflecting a secular change such as variation between valves, a valve for adjusting an intake air amount, and a deposit around an intake valve. Note that the above-mentioned control amount is the opening degree of the valve and the open / close duty ratio.

Here, in the intake air amount control at the time of idling after the completion of the warm-up, which of the various correction control amounts described above is shared by the throttle valve 9 and which of the various control amounts is shared by the bypass air valve 20 is determined by various corrections. It is determined based on the magnitude of the change in the control amount. Here, the control amounts (the air-conditioner correction amount, the idle speed control correction amount by purging, the power steering load correction amount, the rotation change correction amount, the deceleration idle-up correction amount, the cruise control control amount) with which the temporal change becomes large are determined. 9 and the remaining control amount is shared by the bypass air valve 20.

The throttle valve 9 can secure a larger flow rate, and the throttle valve 9 is superior in responsiveness when changing the flow rate. Therefore, here, the requested control amount is reliably realized with good responsiveness by sharing the control amount with a large change amount to the throttle valve 9. As described above, when the required intake air amount is obtained as the sum of the various correction control amounts, if the sharing between the throttle valve 9 and the bypass air valve 20 is determined based on the magnitude of the change amount of the various correction control amounts, Reliable and reliable control can be performed.

In the present embodiment, the throttle valve 9 side can secure a larger intake air amount and its response is good. Therefore, the control amount having a large change amount is assigned to the throttle valve 9 side. Depending on the configuration of the intake control device, there may be a case where the control of a large control amount is controlled by the bypass air valve 20 side.

Next, still another embodiment of the present invention will be described. This embodiment relates to an application of the embodiment described first.

After the control of the intake air amount at the time of idling after the completion of the warm-up operation is completely shifted to the throttle valve 9 side,
A flow learning value for the electronically controlled throttle valve 9 is calculated. In the present embodiment, from the flow rate learning value for the throttle valve 9, a flow rate learning value for the bypass air valve 20 having an equivalent flow rate is calculated, and E is calculated.
It is stored in a memory or the like in the CU 18. Then, this value is used as a learning value of the flow rate of the bypass air valve 20 at the next start. In this way, the latest flow rate learning value can always be reflected in the intake control. At this time (at the time of the next start), control is performed to close the throttle valve 9 from the starter opener degree to the fully closed position.

The throttle valve 9 secures an intake air amount necessary for the limp-home running when the engine 1 is stopped, in consideration of a case where the electronically controlled throttle valve 9 fails and becomes inoperable at the next start. Therefore, it is in an open state to some extent. If the throttle valve 9 is opened to some extent when the engine 1 is stopped, the engine 1
Also, the throttle valve can be prevented from sticking during the stop. The starter opener is the opening of the throttle valve 9 at this time. At the next start, the throttle valve 9 is opened by the opening amount at the start before the engine 1 is started. However, in order to perform the above-described control, the throttle valve 9 is temporarily closed immediately after the engine 1 is started. Closed. Then, the intake air is gradually switched from the bypass air valve 20 side to the throttle valve 9 side thereafter.

It is also possible to store a flow rate learning value for the throttle valve 9 in the memory, and to convert it to a flow rate learning value for the bypass air valve 20 which becomes equivalent to the flow rate when this value is used.

The present invention is not limited to the above embodiments. For example, in the above-described embodiment, the rich gas supply means is a blow-by gas reduction mechanism, but may be another mechanism such as an evaporative fuel purge mechanism, or a combination thereof. Further, in the above-described embodiment, after the warm-up is completed, all the intake air to the cylinder 3 is supplied on the throttle valve 9 side.
1 and the bypass air valve 20 may be used together (that is, after the warm-up is completed, a part of the intake air to the cylinder 3 is supplied to the throttle valve 9 side).

[0044]

According to the first aspect of the present invention, the swirl combustion is effectively performed by the jet port, and the intake air amount at the time of idling is accurately controlled to realize a stable idling state. be able to. According to the second aspect of the invention, when the required intake air amount is obtained as the sum of the various correction control amounts, the sharing of the various correction control amounts by the throttle valve or the bypass air valve is changed by the change amount of the various correction control amounts. Therefore, the intake air amount control can be performed stably and with good responsiveness.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an internal combustion engine having one embodiment of a control device of the present invention.

FIG. 2 is a plan view showing the vicinity of an intake port of the internal combustion engine shown in FIG.

FIG. 3 is a flowchart showing intake air amount control according to an embodiment of the control device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine), 4 ... Intake passage, 4b ... Intake port, 9 ... Throttle valve, 11 ... Bypass passage, 1
1a: jet port, 12: recirculation path, 13: air flow meter, 18: ECU, 20: bypass air valve.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 21/06 F02D 21/06 45/00 314 45/00 314C F02M 25/06 F02M 25/06 (72) Inventor Hiroki Ichinose 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Yuichi Kato 1 Toyota Town Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Koichi Satoya Toyota City, Aichi Prefecture No. 1 Toyota-cho F-term in Toyota Motor Corporation (reference) JA04 JA09 JA11 KA02 KA12 3G084 BA05 BA06 BA21 CA01 CA03 CA07 DA02 DA23 EC03 FA00 FA20 FA27 FA33 FA38 3G092 AA01 AA05 AA13 BA 01 BA03 DC03 DC04 DG08 EA11 EB05 EB08 FA14 FA15 FA40 GA04 HA01Z HA06Z HC05Z HD02Z HD06Z HE01Z HE03Z HE08Z HF04Z HF08Z HF17Z 3G301 HA14 HA17 HA19 JA02 JA05 KA01 KA07 KA28 LA03 LA04 LC03 ND21Z01 PD03

Claims (2)

[Claims] 1. An electronically controlled throttle valve disposed on an intake passage of an internal combustion engine for adjusting an intake air amount,
Provided to bypass the throttle valve,
A bypass passage whose downstream end is connected near the intake valve of the intake port, a bypass air valve for adjusting the amount of air passing through the bypass passage, and a rich gas downstream of the throttle valve on the intake passage. An intake control device for an internal combustion engine, comprising: a rich gas supply unit for supplying, after the warm-up of the internal combustion engine is completed, a part or all of the intake air amount control during idling is performed by the throttle valve. An intake control device for an internal combustion engine. 2. When the throttle valve partially controls the intake air amount during idling after the completion of warm-up of the internal combustion engine, a required intake air amount of the internal combustion engine is obtained as a sum of various correction control amounts. And determining which of the various correction control amounts is to be shared by the throttle valve and which of the various correction control amounts is to be shared by the bypass air valve, based on the magnitude of the variation of the various correction control amounts. An intake control device for an internal combustion engine according to claim 1.