JPS58195009A - Air-fuel ratio controller for internal-combustion engine - Google Patents

Abstract

PURPOSE:To aim at making an air-fuel ratio alterable in a continuous manner as well as to improve a running feeling ever so comfortable, by having a separate secondary air leading port, in addition to the main secondary air leading port, opened on the upper course from an oxygen concentration detector. CONSTITUTION:When the air-fuel ratio of a fuel-air mixture at the suction side is not within the range of a specified value, an electronic control circuit 16 gives a signal for correcting this disparity to an air-fuel control motor inside a carburetor 11 and adjusts the mixture ratio. Secondary air to be added to an exhaust system for exhaust purification is added to the upstream of a catalytic converter 13 via a pipe 19 by operating a secondary air feeder 18. Aside from this, when an engine 1 is in a cooling state or when a car mounting the engine 1 is in a state of acceleration or running at the top speed, the electronic control circuit 16 makes a secondary air control valve 22 open and mixes the secondary air inside an exhaust manifold 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air-fuel ratio control device for an internal combustion engine, which lowers the air-fuel ratio when the engine is cold, when the vehicle is accelerating, when running at full throttle, and under other conditions. be.

As one method of exhaust purification, internal combustion engines are equipped with an oxygen concentration detector that detects the residual oxygen concentration in the exhaust gas, and the signal from this &*d1 degree detector is used to supply oxygen to the internal combustion engine. There is a system that controls the air-fuel ratio of the air-fuel mixture to a specific value. In this case, the only factor that controls the air-fuel ratio of the air-fuel mixture in the intake system is the residual oxygen concentration in the exhaust, and other factors are not involved, so this is not always the case in internal combustion engines for vehicles. However, it was not easy to use, and it sometimes affected riding comfort.

The present invention has been made in view of the above-mentioned problems, and has solved the above-mentioned problems. For this reason, the present invention provides a main secondary air inlet opening to the exhaust line and a separate second
The configuration is such that the secondary air inlet is open.

Hereinafter, one embodiment of the present invention will be explained with reference to FIG.
1 is an engine (internal combustion engine, hereinafter the same), 2 is a piston, 3 is a connecting rod, 4 is a crankshaft, 5 is a spark plug, 6 is a combustion chamber, 7 is an intake manifold, 8 is an exhaust manifold , 9 is an intake pulp, and 10L exhaust valve. The intake manifold 7 of the intake system is connected to the air cleaner 2 via a carburetor (feedback carburetor) 11.

An exhaust manifold 8 of the exhaust system is integrally connected to an exhaust pipe 14 to which a catalytic converter 3 is connected midway. An oxygen concentration detector 15 is installed at the connection between the exhaust manifold 8 and the exhaust pipe 14.
is installed to detect the residual oxygen concentration in the exhaust gas in this area. The output side of this oxygen concentration detector 15 is connected to an electronic control circuit (central processing unit, C, P
, U) connected to the 160 input side. Electronic control circuit 1
The output side of 6 is connected to an air-fuel ratio control motor (not shown) provided inside the carburetor 1.

1. The air cleaner 2 is provided with a muffling chamber 17, and a secondary air supply device 18 is connected between the muffling chamber 17 and the upstream side of the catalytic converter 3 of the exhaust pipe 14. A main secondary air pipe 19 is connected.

A pump or reed pulp can be used as the secondary air supply device [18].

In a part of the exhaust manifold 8 that is the exhaust system, upstream of where the oxygen concentration detector 15 is attached, there is a second secondary air pipe that is different from the secondary air pipe 19 described above. One end of 20 is open. This second
The other end of the secondary air pipe 2o is connected to a silencing chamber 17 of the air cleaner 12. In the middle of this second secondary air pipe 2o, a secondary air supply device 21 of the same type as the one denoted by reference numeral 18 and a secondary air control pulp 22 are connected in series. .

This device configured as described above operates as follows. That is, when the engine 1 operates, the oxygen concentration detector 15 detects the residual oxygen concentration in the exhaust gas and outputs it to the electronic control circuit 16. The electronic control (b) path 16 judges this signal, and if the air-fuel ratio of the air-fuel mixture on the intake side, which is judged from the value, is not within the specified range, it sends a signal to correct this to the air-fuel ratio control inside the carburetor 11. Apply it to the motor and adjust the mixture ratio to make it suitable for the combustion chamber 6.

ensure that a suitable air-fuel ratio is obtained.

− On the other hand, secondary air added to the exhaust system for exhaust purification is
A secondary air supply system f is provided by the main secondary air pipe 19.
It will be added to the -F flow of the catalytic converter 13 when ii1g is activated (or opened). This secondary air provides good exhaust gas purification. Separately, by opening the secondary air control pulp 22 when the engine 1 is in a cold state, or when the vehicle equipped with the engine 1 is accelerating or running at full throttle, or under other conditions, the exhaust manifold Secondary air will be mixed into the air.

This secondary air is given to Wt above the acid As a result, the electronic control circuit 16 issues a command to the air-fuel ratio control motor inside the carburetor 11 to obtain a rich mixture ratio.

For this reason, when the engine is running at 11, or when the vehicle is accelerating suddenly or running at full throttle, in other words, when you want to supply a rich mixture to the combustion chamber 6 of the engine, you can Intake negative pressure, temperature,
If the secondary air control pulp 22 is opened in response to an output signal from a sensor that detects pressure, rotational speed, acceleration, etc., a rich air-fuel mixture can be supplied to the fuel-yaa6.

What is shown in FIG. 2 is another embodiment of the present invention. In this case, the distribution of secondary air flowing from one secondary air supply source through the control valve 23 into the secondary air pipes 19 and 20 is controlled. In this device, chain 1
This means that the structure is simpler and smaller than the one shown.

Since the present invention is configured as described above, the basic air-fuel ratio of the capretor can be changed by cutting off or turning off the electronic control circuit or adding a complicated circuit, as was done in the past. It allows for more natural switching than the one that controls the carburetor by issuing a signal that makes it look darker or darker, and it is advantageous in terms of driving feeling because it does not allow continuous changes in the air-fuel ratio. This allows for greater control.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of one embodiment of the present invention, and FIG. 2 is a partial system diagram of another embodiment of the present invention. ■・・・・・・・・・Engine 7・・・・・・Intake manifold 8′...
...Exhaust manifold 11...
・・Kikibureta: 1゜12100. -- -41A, Reach ll'l'l
l:13...Catalytic converter 14...Air sheath pipe 15...Oxygen concentration detector 16...Electronic control circuit 18.21...・Secondary air supply device 19...
...Secondary air pipe 20...Second secondary air pipe 22...
...Secondary air control pulp special plan applicant Suzuki Motor Co., Ltd. (and one other person) □,. '1:.

Claims (1)

[Claims] (1) In an internal combustion engine that is equipped with an oxygen concentration detector to detect the residual oxygen concentration in the exhaust gas and adjust the air-fuel ratio on the intake side, detecting the oxygen concentration in the exhaust system with the acid level detector installed. This air-fuel ratio control device for an internal combustion engine is specially designed to have a second secondary air pipe, which is different from the main secondary air pipe that opens into the exhaust system, opened upstream of the engine.