JPS5913308Y2 - Exhaust gas purification device for multi-cylinder engines - Google Patents

Description

[Detailed description of the invention] This invention detects the components of exhaust gas using the activation signal from the exhaust gas component detection device installed in the exhaust system, and creates a three-way atmosphere required by the three-way catalyst device installed in the exhaust system. The present invention relates to an exhaust gas purification device for a multi-cylinder engine that controls exhaust gas components.

Conventionally, in order to improve output, a plurality of cylinders were provided, mutually independent intake passages for introducing intake air into each cylinder were formed as two intake passage groups, and each intake passage group was provided with a first and a second carburetor. Multi-cylinder engines equipped with an intake system are known.

In addition, the mutually independent exhaust pipes that release exhaust gas from each cylinder are formed into two exhaust pipe groups, and one end of each exhaust pipe group is connected to the gathering part of the two connecting pipes, and the other end of the two connecting pipes is connected to the gathering part of each exhaust pipe group. A multi-cylinder engine is provided with an exhaust system in which one end is connected to the gathering part of the connecting pipe and the other end is open to the atmosphere, and the exhaust system is designed to improve output by eliminating exhaust interference of each cylinder. (For example, see Japanese Utility Model Application Publication No. 53-83913) is also known.

The present invention is intended to control the exhaust gas atmosphere introduced into the three-way catalyst device installed in the outlet pipe into a three-way atmosphere in a multi-cylinder engine equipped with the above-mentioned intake system and exhaust system.
Appropriate layout of the intake system and exhaust system so that the exhaust system is provided with an exhaust gas component detection device that detects exhaust gas components, such as oxygen or carbon monoxide, and issues an activation signal to a correction device that corrects the exhaust gas components. It provides:

That is, the present invention detects the exhaust gas components of the cylinders into which intake air is introduced from the first carburetor and the second carburetor using one exhaust gas detection device, and the detection device is relatively An object of the present invention is to provide an exhaust gas purification device for a multi-cylinder engine, which is installed in a nearby position and allows the detection device to operate accurately.

Embodiments of the present invention will be described below with reference to the drawings.

1 to 4 are the first to fourth cylinders that make up the four-cylinder engine E, and are usually the first cylinder 1, the third cylinder 3, the fourth cylinder 4, and the second cylinder 2.
Ignition takes place in this order.

A first carburetor 11 is provided in a first intake passage group 9 constituted by the intake passages 5 and 6 of the first and second cylinders 1 and 2, and has a throttle valve 12 and a venturi 13.

A second carburetor 14 is provided in a second intake passage group 10 constituted by the intake passages 7 and 8 of the third and fourth cylinders 3 and 4, and has a throttle valve 15 and a venturi 16.

Note that 17 is an air cleaner.

The exhaust system 20 of the engine E is configured as a dual exhaust system.

That is, among the exhaust pipes 21 to 24 connected to each cylinder 1 to 4, the exhaust pipe 21 of the first cylinder 1 introduces intake air from the first carburetor 11, and the fourth exhaust pipe 21 introduces intake air from the second carburetor 14. The exhaust pipes 24 of cylinder 4 are collected as a first exhaust pipe group 25, and the remaining exhaust pipes 22 and 23 of the second and third cylinders 2 and 3 are collected as a second exhaust pipe group 26. A first connecting pipe 27 connected to the first exhaust pipe group 25 and a second connecting pipe 28 whose one end is connected to the second exhaust pipe group 26 are brought together at the other end, while an end open to the atmosphere 30a, one end of which is open to the atmosphere, and a three-way catalyst device 31 is interposed therebetween, is connected to the first connecting pipe 27 and the second connecting pipe 2.
8, and the exhaust system 20 of a so-called dual exhaust system is configured as a whole.

33 is provided at the gathering part 32 of the first exhaust pipe group 25, detects the components of exhaust gas, such as oxygen concentration, and issues an activation signal to the controller 34 in accordance with the oxygen concentration, details of which are not shown in the figure. However, the exhaust gas components control the opening and closing operations of the solenoid valves that correct the air bleed amount of the main nozzles of the first and second carburetors 11 and 14, and operate the correction devices 35 and 36 that correct the exhaust gas components. It is a detection device.

With this configuration, since a dual exhaust system is used as the exhaust system 20 without exhaust interference, it is possible to improve the output compared to an exhaust system in which the exhaust pipes of each cylinder are gathered together in the exhaust manifold.

In addition, since the exhaust gas component detection device 33 is provided at the gathering part 32 of the first exhaust pipe group 25, the first connecting pipe 27 and the second
Compared to the case where the exhaust gas component detection device is provided at the gathering part 29 of the connecting pipe 28, the exhaust gas component detection device 33 is exposed to relatively high temperature exhaust gas, so the exhaust gas component detection device 3
3 can be operated accurately.

Furthermore, the exhaust pipes 21.24 of the first and fourth cylinders 1.4, which introduce intake air from the first and second carburetors 11.14, are
The exhaust pipes 21 of the first and second cylinders 1 and 2 into which intake air is introduced from the first carburetor 11 are collected as an exhaust pipe group 25, and the exhaust gas component detection device 33 is provided in this collection part 32.
．． 22 are collected as the first exhaust pipe group, and the second carburetor 1
When the exhaust pipes 23.24 of the 3rd and 4th cylinders 3 and 4 that introduce intake air from the 4th cylinder are combined as the 2nd exhaust pipe group, the air-fuel mixture from the 1st and 2nd carburetor 11.14 is combusted. In order to detect the components of the exhaust gas generated by The device 33 can detect the components of the exhaust gas generated by combustion of the air-fuel mixture from the first and second carburetors 11.14, thereby providing a relatively inexpensive exhaust gas purification device for a multi-cylinder engine. can do.

In addition, in the above embodiment, the gathering portion 32 of the first exhaust pipe group 25
Although the exhaust gas component detection device 33 is provided at the second exhaust pipe group 26, it is clear that similar effects can be obtained even if the exhaust gas component detection device 33 is provided at the gathering portion of the second exhaust pipe group 26.

In addition, in the above embodiment, the exhaust pipes of the cylinders with non-consecutive ignition orders are grouped together, but due to the occurrence of multi-generation exhaust interference, the effect of improving output is somewhat inferior.
Each cylinder 1. 2. 3. If the first and second intake passage groups 9 and 10 are made bilaterally symmetrical as in the above embodiment in consideration of the distribution of the air-fuel mixture of
The exhaust pipes 21.23 of the cylinders 1 and 3 can be combined, and the exhaust pipes 22.24 of the second and fourth cylinders 2°4 can be combined.

In short, one row of exhaust pipes of a cylinder into which intake air is introduced from the first carburetor 11 and one row of exhaust pipes of a cylinder into which intake air is introduced from the second carburetor are collected together to form an exhaust pipe group. As long as the exhaust gas component detection device is provided at the collection point of the group, the number of exhaust pipes, the ignition order, etc. do not matter.

Furthermore, in the above embodiment, a correction device that controls the air bleed amount of the main nozzle is used as a correction device for correcting exhaust gas components, but the correction device controls the amount of primary air that bypasses the first and second carburetors. It is possible to use one that controls the amount of secondary air supplied to the exhaust gas or one that controls the amount of secondary air supplied to the exhaust gas.

As is clear from the detailed description above, according to the present invention, the structure of the intake system and the exhaust system makes it possible to improve the output, and also to improve the output of the intake system and the exhaust system. By providing an exhaust gas component detection device on one side, the exhaust gas component detection device can be operated accurately, and a relatively inexpensive exhaust gas purification device for a multi-cylinder engine can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS The drawing is a system diagram of an engine showing an embodiment of the present invention. E... Engine, 1 to 4... Cylinder, 5 to 8... Intake passage, 9... First intake passage group, 10... Second intake passage group, 11... First vaporization vessel, 14...second carburetor, 20...exhaust system, 21-24...exhaust pipe, 25.
...First exhaust pipe group, 26...Second exhaust pipe group, 27...
・First connecting pipe, 28... Second connecting pipe, 29... Collection part, 30... Leading pipe, 31... Catalyst device, 32...
・Collection part, 33...Exhaust gas component detection device, 35...
- First correction device, 36... second correction device.

Claims (1)

[Scope of utility model registration request] In a multi-cylinder engine including a plurality of cylinders, two groups of mutually independent intake passages introducing intake air into each cylinder are formed, and each group of intake passages is provided with a first and a second carburetor, respectively. Of the exhaust pipes connected to each cylinder,
The exhaust pipes of one part of the cylinder that introduces intake air from the first carburetor and the exhaust pipe of one part of the cylinder that introduces intake air from the second carburetor are collected as a first exhaust pipe group, and the exhaust pipes of the remaining cylinders are The pipes are collected as a second exhaust pipe group, and a first connecting pipe whose one end is connected to the first exhaust pipe group and a second connecting pipe whose one end is connected to the second exhaust pipe group are connected to each other. An outlet pipe having an end open to the atmosphere and having a catalyst device interposed therein is connected to the meeting part of the first connecting pipe and the second connecting pipe, and the first and second exhaust pipe groups 1. An exhaust gas purification device for a multi-cylinder engine, characterized in that an exhaust gas component detection device that issues an activation signal to a correction device that corrects exhaust gas components is provided on one side of the collecting section.