JPS5974360A - Air-fuel ratio controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To improve the car-mounting characteristic of a controller as well as to cut manufacturing costs, by attaching an exhaust gas sensor to the vicinity of a coupling part of an exhaust pipe, while installing an exhaust emission controlling catalyzer in the downstream side of each coupling part, and regulating the quantity of air in a bleed air passage. CONSTITUTION:Exhaut pipes 111, 112 and 113, 114are coupled with each other at the rear part away from an engine 1, and ternary catalyzers 131 and 132 are installed at the downstream side of each of coupling parts 11a and 11b. At a spot around the coupling part 11a, one O2 sensor 12 is installed. An actuator 30 controlling the air-fuel ratio in each of carburetors 141-144 regulates the quantity of air to be bled into each of concentrated interconnecting parts 26a and 26b. This actuator 30 is controlled by an electronic controller 33 in accordance with the output of the O2 sensor 12. Thus, the air-fuel ratio in eacy cylinder can be collectively controlled with a pair of air-fuel ratio controllers, meaning that improvements in a car-mounting characteristic and a reduction in manufacturing costs are brought to fruition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air-fuel ratio control device for an internal combustion engine, and more particularly to an air-fuel ratio control device for an internal combustion engine with a multi-cylinder long-range carburetor.

In an internal combustion engine installed in a vehicle, an exhaust gas purifying catalyst is installed in the exhaust pipe, and an exhaust gas sensor is installed on the upstream side of this catalyst.The exhaust gas sensor detects the composition ratio of the exhaust gas leading to the catalyst, and this detection signal is An air-fuel ratio control device is already known that controls the air-fuel ratio of an intake air-fuel mixture of an engine based on the following and performs feedback control so that the composition ratio of exhaust gas becomes an optimal value that is best purified by a catalyst.

As a 14-gas sensor, a 02 sensor is generally used to detect the oxygen concentration in exhaust gas, and as a catalyst, it detects hydrocarbons HC, -oxidants C○, and nitrogen oxides NOx in the exhaust gas. When a three-way catalyst is used, which removes the exhaust gas by oxidation and reduction, the optimum value of the exhaust gas purified by the three-way catalyst is feedback-controlled so that it becomes the stoichiometric air-fuel ratio.

The intake of fresh air mixture into the engine combustion chamber of an internal combustion engine and the scavenging of exhaust gas from the combustion chamber are performed by the reciprocating movement of screws and the corresponding opening and closing operations of the intake valve and exhaust valve. The exhaust gas pressure pulsation and inertia are utilized to further complete this scavenging and increase the engine output. For this reason, an exhaust pipe having an appropriate length is attached to the exhaust passage of the engine. In a multi-cylinder internal combustion engine, in order to obtain high output, an independent exhaust pipe is provided for each cylinder so that pulsations in exhaust gas pressure of each cylinder do not interfere with each other. In addition, to further increase engine output,
In some cases, a carburetor is provided for each cylinder, and each carburetor independently generates an intake air mixture. In such an internal combustion engine with multiple cylinders and multiple carburetors, if the above air-fuel ratio control device is applied to each cylinder of the engine, an actuator for air-fuel ratio control and an exhaust gas sensor must be installed for each carburetor, which increases costs. This is a contributing factor.

The present invention has been made in view of the above points, and is an air-fuel ratio control device for an internal combustion engine with multiple cylinders and multiple carburetors having independent exhaust pipes and carburetors for each cylinder. At least two or more exhaust pipes are connected, an exhaust gas sensor is installed near at least one connecting part, an exhaust purification catalyst is arranged downstream of each connecting part, and the exhaust pipes are connected to the fucoel jet 1 of each vaporizing H( One end of the bleed air passage is collectively connected, and the air series ff1 flowing into the collective communication part is adjusted according to the output signal of the exhaust gas sensor, and the - set of air-fuel ratio control devices is used to control each vaporization H (÷ An object of the present invention is to provide an air-fuel ratio control device for an internal combustion engine with multiple cylinders and multiple carburetors that is inexpensive and easy to install on a vehicle by collectively controlling the air-fuel ratio in the engine.

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a schematic side sectional view of an example in which the device of the present invention is applied to an internal combustion engine with four cylinders and four carburetors, and FIG. 2 is a bottom view.

A four cylinder, four carburetor engine (only one of the cylinders is shown in FIG. 1) has screws 1 to 3 that reciprocate within the cylinder block 2. The engine has an intake valve 7 and an exhaust valve 8 that respectively open and close the intake port 5 and exhaust port 6 of the six chambers 4 in response to the reciprocating motion of the piston 3, and each port h5, 6 is connected to an intake passage 9. It is connected to an exhaust passage 10.

Independent exhaust pipes 3-++, , 1.12, 113, 114 are connected to each exhaust passage 10 of each cylinder, and exhaust pipes 11. , exhaust pipe 112 , exhaust pipe 113 , and exhaust pipe 114
are connected at the rear part separated from the engine 1, and a three-way catalyst '
3++ 132 are arranged respectively. Also, two connecting parts], Ia, 11. One 02 sensor 12 is attached to one side of the connecting portion 11a of the connecting portion 11a.

Each carburetor 141 is connected to each intake passage 9 of each cylinder, respectively.
, 142, 143, and 144, a throttle valve 16 is provided on the downstream side of each passage 15, and the upstream side of each passage 15 is connected to the downstream side of an air cleaner 17. Each vaporizer 14. ~14. are the main Tsuyuel Jet 18 respectively.
and a slow type fuel jet 19, and emulsion pipes 20 and 21 are installed inside each of these fuel jets 18 and 19, respectively. In addition, each vaporizer 14, ~1
4 and 4 each have a vacuum piston 23 having a jet needle 22, and each vacuum piston 23 is mounted so that the cross-sectional area of each passage 15 can be varied. A main fuel jet 18 is installed on the side wall of each passage 15 facing each comb screw 1-23.
Jet needles 22 attached to vacuum screws 1 to 23 are inserted into each of the jet ports 24, respectively.

The ejection port 25 of each slow fuel jet 19 is formed in the side wall of each passage 15 near the respective throttle valve 16. Each vaporizer 14. ~14. .

are two systems of bleed air passages that supply air to each of the main system fuel jets i to 18 and the slow system fuel jet 19, that is, the main system bleed air passage 26.
．． ．． 26□+263+26. + and slow system bleed air passages 271+ 272 +2731274, and each main system bleed air passage 26. - 264 are gathered into a single line at a collective communication section 26a, and an air intake port 26b of the collective communication section 26a is connected to a communication section 29 connected to the downstream side of the air cleaner 17 by a pipe line 2B.

Similarly, each slow system bleed air passage M27°~27
4 are also joined together at the collective communication part 27a, and the air intake port 27b is connected to the communication part 29. Each vaporizer 14. The actuator 30 for controlling the air-fuel ratio in steps 1 to 144 is composed of, for example, a step motor, and has needles 3+, 32 in the communication section 29, and moves the needles 3+, 32 back and forth with the step motor to control each collective communication section 2.
6a.

The opening degrees of the air intake ports 26b and 271) of the air intake ports 27a are adjusted to adjust the amount of air extracted from the conduit 28 to the collective communication portions 26a and 27a.

The actuator 30
It is electrically connected to the sensor 12.

The operation of the air-fuel ratio control device shown in FIGS. 1 and 2 will be explained below.

When the engine 1 is driven and the piston 3 and the exhaust valve 8 operate, exhaust gas is discharged into each of the exhaust pipes 111 to 11,I. ,．． Exhaust gas flowing through the exhaust gases 112 joins together at the connecting portion 11a, is purified by the three-way catalyst 131, and then released into the atmosphere. Also, exhaust pipe 11. ,．． 11.
The exhaust gases flowing through the exhaust gases are combined at the connecting portion 11b, purified by the three-way catalyst 132, and then released into the atmosphere. Exhaust pipe 111°112 and exhaust pipe +13.11. , are symmetrical as clearly shown in FIG.
The output signal of the 02 sensor 12 installed near a is transmitted to each exhaust pipe 11. ~111. This is considered to indicate the average oxygen concentration in the exhaust gas flowing through the area.

When the throttle valve 16 is close to the fully open state, the airflow velocity flowing through the passage 15 near the jet nozzle 24 is high, so the fuel mixture is mainly injected and supplied into the respective passage 15 from each main system fuel jet I-18. be done. Furthermore, when the throttle valve 16 is throttled, the airflow velocity near the jet port 25 is high, so that the fuel mixture is mainly injected and supplied from each slow system fuel jet 1-19 into the respective passage 15. . Then, the mixture is in each passage 15
It is emuldiminated to a higher density within the container. At this time, each exhaust pipe 11. ~1] The electronic control unit 33 controls and drives the actuator 30 based on the output signal of the sensor 12, which is considered to indicate the average oxygen concentration of the exhaust gas flowing through the passageway 29, and the needle 31. 32, and main system bleed air passages 261 to 26. The air intake port 26b of the collective communication portion 26a of
The opening degree of the air intake port 27b of the collective communication section 27a of the slow system bleed air passages 27 and 274 is adjusted, respectively, and the air is passed from the downstream side of the air cleaner 17 through the conduit 28 to each collective communication section 26a.

The amount of air flowing into each of 27a is adjusted. Collective communication section 2
The air flowing into each vaporizer 14. ] 44 main system bleed air passages 261 to 264, respectively, to each vaporizer 14. ~144 main system Fucoel jets 18.

The air that has flowed into the collective communication section 27a is transferred to each of the vaporizers 14, .
The air is branched to each slow system bleed air passage 271 to 274 of 144 and supplied to each slow system Fucoel jet 19 of each vaporizer 14+ to 14□1, respectively. Therefore, each vaporizer 1
4. Since the amount of air in the fuel mixture injected into each passage 15 from the injection port 24.25 of each Fucoel jet 18.19 of ~144 is adjusted, The air-fuel ratio of the air-fuel mixture is controlled. In this way, the average oxygen concentration in the exhaust gas flowing into each exhaust pipe 111-114 is detected, and the air-fuel ratio in each carburetor 141-14, 1 is collectively controlled based on this average oxygen concentration. can do.

FIG. 3 schematically shows another embodiment of the device of the present invention applied to a motorcycle, and FIGS. 4 and 5 show main parts of the embodiment shown in FIG. 3. In addition, Fig. 1.

Components that are the same as those shown in FIG. 2 are designated by the same reference numerals.

When a motorcycle is equipped with an air-fuel ratio control device according to the feedback control of the present invention, the engine and the like are exposed, so the actuator 30 is exposed to rain, muddy water, etc. Furthermore, since the actuator 30 has the needles 3+ and 32, the vibrations of the engine cause the needles 3+ and 32 to
If needle 11.2 breaks or vibration of needle 11.32 occurs, the error in the air-fuel ratio control value increases. Therefore, in this embodiment, an actuator 30 is used to control the air-fuel ratio.

As schematically shown in FIG. 3, the actuator 30
to protect it from rain, muddy water, etc. Also, the fifth
As shown in the figure, the actuator 30 is fixed to the horns 34, 34 of the vehicle body via rubber mounts 35, 35 and stays 36, 36 fixed to the frame 34, 34 by welding or the like. Additionally, each vaporizer has 14 volts + 1
42+ "3+14, I's main fuel jet l-181.

18□, 1831, 184, respectively, the main system bleed air passages 261, 2G2. Bleed air passage 27.

The middle part of the collective communication part 27a of 272+ 273127-1 is formed by elastic tubes 37 and 38 made of rubber or the like, respectively. Therefore, the actuator 30 is protected from vibrations of the engine 1, and the durability of the actuator 30 is increased.

In the embodiment of the present invention shown in FIG. 2 or FIG. 5, each of the four carburetors has two passages, a main bleed air passage and a slow bleed air passage. The air passages of each vaporizer are connected together into one,
Each collective communication portion 26a.

The amount of air flowing into 27a is adjusted,
The present invention is not limited to this, and only one system of bleed air passages may be collectively communicated with one other. Also,
The present invention is not limited to the case where there are two bleed air passages, but it is sufficient that each cylinder has one or more bleed air passages.

As described above, the present invention provides an air-fuel ratio control device for an internal combustion engine with a multi-cylinder long-run carburetor, which has independent exhaust pipes and carburetors for each cylinder. Two or more of them are connected, an exhaust gas sensor is installed near at least one of the connections, an exhaust purification catalyst is arranged downstream of each connection, and the exhaust gas sensor is connected to the fuel jet of each carburetor. One end of the bleed air passage is connected in a collective manner, and the amount of air flowing into the collective communication part is adjusted according to the output signal of the exhaust gas sensor. 11- The air-fuel ratio can be controlled all at once, making it easy to mount on vehicles and reducing manufacturing costs.

[Brief explanation of drawings]

Fig. 1 is a schematic side sectional view of a device according to an embodiment of the present invention, Fig. 2 is a bottom view of a device according to an embodiment of the present invention, and Fig. 3 is a schematic diagram of a device according to another embodiment of the present invention applied to a motorcycle. The side view, FIGS. 4 and 5 are explanatory diagrams of the embodiment shown in FIG. 3. 1... Internal combustion engine, +1 +, 112.113.
11.1...Exhaust pipe, Ila...Connection part, 12...
・Exhaust gas sensor (02 sensor), +3. ,+32・
・・Exhaust purification catalyst (three-way catalyst), L4. ．． 142
．． ]/I3,14. ...vaporizer, 18.18+. 182.183.18□,...Main fuel jet, 19.191.192, If) 3.104...
・Slow fuel jet 1~. 26. ．． 26□, 26
3,264... Main system bleed air passage, 271.
272.273.274... Slow system bleed air passage, 26a, 27a... Collective communication section. Applicant Honda Motor Co., Ltd. Agent Patent Attorney Toshihiko Watanabe 12-

Claims (1)

[Claims] (2) In an air-fuel ratio control device for an internal combustion engine with a multi-cylinder long-run carburetor, which has independent exhaust pipes and carburetors for each cylinder, at least two or more of each exhaust pipe are connected at a rear position away from the engine, and at least An exhaust gas sensor is installed near one connection, an exhaust purification catalyst is arranged downstream of each connection, and one end of the bleed air passage connected to the tsuyuel jet of each carburetor is connected collectively. An air-fuel ratio control device for an internal combustion engine with a multi-cylinder long-range carburetor, characterized in that the amount of air flowing into the collective communication section is adjusted in accordance with the output signal of the exhaust gas sensor.