JP3373906B2 - Engine exhaust purification device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an engine exhaust system,
The present invention relates to an exhaust gas purifying apparatus for an engine, in which an HC trapper that adsorbs HC at low temperatures and a catalytic converter that activates at high temperatures are interposed to remove HC and other harmful components contained in exhaust gas of the engine.

[0002]

2. Description of the Related Art This type of exhaust emission control device is already known, as disclosed in, for example, Japanese Patent Laid-Open No. 3-141816.

[0003]

Conventionally, in this type of exhaust gas purification device, an adsorption trapper and a catalytic converter are serially inserted in series from the upstream side to the exhaust pipe connected to the collecting pipe of the exhaust manifold. By the time exhaust gas in the combustion chamber reaches the catalytic converter, a large amount of heat of the exhaust gas is taken by the exhaust manifold with a large heat mass. Therefore, it takes a long time to activate the catalytic converter after starting the engine. There is a problem that

The present invention has been made in view of the above circumstances, and an object thereof is to provide an exhaust gas purification device capable of activating a catalytic converter early and increasing the purification rate after engine startup. To do.

[0005]

In order to achieve the above object, the present invention provides, for each combustion chamber, first and second exhaust ports whose inner ends are opened in the chamber and which are individually opened and closed. In an engine including first and second exhaust valves, a branch pipe of a first exhaust manifold is provided at an outer end of a first exhaust port of each combustion chamber, and a branch of a second exhaust manifold is provided at an outer end of a second exhaust port. The exhaust pipes are connected to each other, and the collecting pipes of both exhaust manifolds are connected to a common exhaust pipe. The collecting pipe of the first exhaust manifold is provided with an adsorption trapper that adsorbs HC at low temperature, and the exhaust pipe is provided with a catalytic converter. When the adsorption trapper is installed at a low temperature, the first exhaust valve is operated and the second exhaust valve is stopped so that the exhaust gas of each combustion chamber mainly flows to the first exhaust manifold .
The Nihold branch pipe is the branch pipe of the second exhaust manifold.
The first feature is that each part is formed to have a smaller diameter .

In addition to the first feature of the present invention, when the temperature of the catalytic converter is high, the first exhaust valve is stopped and the second exhaust valve is operated, so that the exhaust gas of each combustion chamber is mainly exhausted from the second exhaust manifold. The second feature is that it is made to flow to the.

Further, according to the present invention, each combustion chamber has an internal
First and second exhaust ports that open at the ends, and these
For an engine having first and second exhaust valves that open and close separately
The first exhaust port at the outer end of the first exhaust port of each combustion chamber.
Install a Nihold branch pipe and a second pipe at the outer end of the second exhaust port.
2 When connecting the branch pipes of each exhaust manifold,
The exhaust pipes of both exhaust manifolds to a common exhaust pipe.
Then, at the low temperature, HC should be supplied to the collecting pipe of the first exhaust manifold.
An adsorption trapper for adsorption and a catalyst converter in the exhaust pipe
The first exhaust when the adsorption trapper is at a low temperature.
Operate the valve and deactivate the second exhaust valve for each combustion
So that the exhaust gas from the chamber will flow mainly to the first exhaust manifold
If the temperature of the catalytic converter is high, turn off the first exhaust valve.
It is stopped and the second exhaust valve is operated to remove exhaust gas from each combustion chamber.
Let the gas flow mainly to the second exhaust manifold,
The second exhaust valve has a larger diameter than the first exhaust valve.
Is the third feature. Furthermore, the present invention, for each combustion chamber,
First and second exhaust ports having an inner end opened to the chamber;
An air conditioner having first and second exhaust valves for individually opening and closing them.
In the engine, the first end of the first exhaust port of each combustion chamber
1 exhaust manifold branch pipe, and the second exhaust port
Connect the branch pipes of the second exhaust manifold to the outer ends.
And the common exhaust of each collecting pipe of both exhaust manifolds
Connected to the pipe, the first exhaust manifold collecting pipe at low temperature
An adsorption trapper that adsorbs HC, and a catalytic converter on the exhaust pipe.
The converter interposed respectively between the first and second exhaust manifold, and their collection tube communicating pipe which communicates with each other provided on the upstream side of the adsorption trapper, between the communicating pipe and the first exhaust manifold, the communicating pipe A switching valve for switching between a first position for shutting off the exhaust gas and a second position for shutting off the collecting pipe of the first exhaust manifold on the inlet side of the adsorption trapper, and operates the first exhaust valve when the temperature of the adsorption trapper is low. The second exhaust valve is stopped and the switching valve is switched to the first position. When the catalytic converter is hot, both the first and second exhaust valves are operated and the switching valve is switched to the second position. This is the fourth feature.

[0008]

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

First, the first embodiment shown in FIGS. 1 to 7 is started.

FIG. 1 is a bottom view of a cylinder head and an intake / exhaust system of a multi-cylinder engine for an automobile. In the figure,
The cylinder head 1 is provided with a plurality of combustion chambers 2, 2 ... Corresponding to a plurality of cylinders, and a pair of intake valve ports 3 ₁ , 3 ₂ and exhaust valve ports 4 ₁ , on the ceiling surface of each combustion chamber 2. 4 ₂ is opened, the pair of intake valves 5 ₁ for opening and closing these, 5 ₂ and the exhaust valves 6 _1, 6 ₂ are provided in the cylinder head 1. In particular, each pair of exhaust valve ports 4 ₁ , 4 ₂ and exhaust valves 6 ₁ , 6 ₂
One of the umbrella portions is formed to have a small diameter and the other is formed to have a large diameter. The small diameter side is referred to as a first exhaust valve port 4 ₁ and a first exhaust valve 6 _1, and the large diameter side is referred to as a second exhaust valve port 4 _2. , Second exhaust valve 6 ₂ .

A bifurcated intake port 7 connecting a branch path to the intake valve ports 3 ₁ , 3 ₂ of each combustion chamber 2 is connected to a branch pipe of an intake manifold 8 on one side surface of the cylinder head 1.

On the other hand, the first exhaust port 10 ₁ connected to the first exhaust valve port 4 ₁ of each combustion chamber 2 is connected to the branch pipe 11a of the first exhaust manifold 11 on the other side surface of the cylinder head 1 and the second exhaust port. The second exhaust port 10 ₂ connected to the valve port 4 ₂ is also the second exhaust port 10 _{2 on} the other side surface of the cylinder head 1.
It is connected to the branch pipe 12 a of the exhaust manifold 12.

First and second exhaust manifolds 11, 12
Are respectively provided with one collecting pipe 11b, 12b, and these are connected to a common one exhaust pipe 13 so as to join at a further downstream end.

Collecting pipe 11b of the first exhaust manifold 11
Is provided with an adsorption trapper 15 containing an HC adsorbent, and a first temperature sensor 17 for detecting the outlet temperature thereof.
At the upstream end of the exhaust pipe 13, a catalytic converter 16
And a second temperature sensor 18 for detecting the outlet temperature thereof. The adsorption trapper 15 has a predetermined temperature (for example, 14
It has the ability to adsorb HC in a low temperature state (below 0 ° C.) and desorb HC in a high temperature state above that. Further, the catalytic converter 16 has a performance of activating at a predetermined temperature (for example, 300 ° C.) or higher to remove HC, CO, and NOx.

Next, an exhaust valve operating system for opening and closing the first and second exhaust valves 6 ₁ , 6 ₂ will be described with reference to FIGS. 2 to 7.

In FIG. 2, an exhaust valve operating system 19 includes a cam shaft 20 driven from a crank shaft (not shown) with a speed reduction ratio of ½, and a rocker shaft 2 parallel to the cam shaft 20.
1. The rocker shaft 21 is provided with one drive rocker arm 22 pivotally supported for each combustion chamber 2 and a pair of first and second driven rocker arms 23 ₁ and 23 ₂ . The normal actuating cam 2 that is in sliding contact with the upper surface of the drive rocker arm 22 is attached to the cam shaft 20.
0a and the circular first and second rest cams 20 slidably contacting the upper surfaces of the first and second driven rocker arms 23 ₁ and 23 ₂ , respectively.
b and 20b are integrally formed, and as shown in FIG. 3, the drive rocker arm 22 is urged by the spring 24 via the guide piston 25 in the contact direction with the actuating cam 20a.

As shown in FIGS. 4 and 5, the first and second driven rocker arms 23 ₁ and 23 ₂ have valve springs 26 ₁ and 26, respectively.
First to be urged in the valve closing direction by _2, the second exhaust valve 6 _1,
It is arranged so that the head of 6 ₂ can be pressed by the tip.

As shown in FIG. 6, the drive rocker arm 22
The first and second driven rocker arms 23 ₁ and 23 ₂ are arranged adjacent to each other so that the driving rocker arm 22 is sandwiched between the two driven rocker arms 23 ₁ and 23 _{2. A} connecting device 27 is provided which can alternately switch between a state in which the drive rocker arm 22 is connected to the _first driven rocker arm 22 and a state in which the drive rocker arm 22 is connected to the second driven rocker arm 23 ₂ .

This connecting device 27 is used for the drive rocker arm 2
2, a connecting pin 29 slidably fitted in a central guide hole 28 opened at both ends, which is bored in parallel with the rocker shaft 21, and aligned with one end of the central guide hole 28 bored in the first driven rocker arm 23 _1. The first piston 31 ₁ slidably fitted in the bottomed first side guide hole 30 ₁ and the second driven rocker arm 23 ₂ can be aligned with the other end of the central guide hole 28. The second piston 3 fitted in the bottomed second side guide hole 30 _2.
1 ₂ and. The connecting pin 29 is formed longer than the central guide hole 28, and has one end protruding from the central guide hole 28 into the first side guide hole 30 ₁ to connect the drive rocker arm 22 to the first driven rocker arm 23 ₁ . 1 connection position (FIG. 6), and from the central guide hole 28 to the second side guide hole 30 ₂
The other end of the driving rocker arm 22 is moved to and from a second connecting position (FIG. 7) where the driving rocker arm 22 is connected to the second driven rocker arm 23 ₂ .

The first connecting position is the first side guide hole 30.
₁The first piston 31 on the step portion 30a of the ₁To abut
The second connection position is regulated by the second side guide hole 30.₂
The second piston 31 on the step portion 30b of the₂Abutting each other
Regulated.

The second piston 3 is inserted into the second side guide hole 30 _2.
A return spring 32 for urging the connecting pin 29 toward the first connecting position via 1 ₂ is contracted. On the other hand, the first side guide hole 30
_A hydraulic chamber 33 facing the outer end of the first piston 31 ₁ is defined in ₂ and the hydraulic chamber 33 defines the oil passage 3 in the rocker shaft 21.
A control valve (not shown) is connected to the hydraulic pressure source or the oil reservoir via 4. Further, in the hydraulic chamber 33, a vibration-proof spring 35 having a weaker force than the return spring 32 is contracted.

Then, as shown in FIG. 6, when the hydraulic chamber 33 is opened to the oil sump, the connecting pin 29 is moved to the first connecting position by the elastic force of the return spring 32, and the drive rocker arm 2 is moved.
2 is connected to the first driven rocker arm 23 ₁ and the second driven rocker arm 23 ₂ is free. In such a state, if the cam shaft 20 is rotating, the operation cam 2
0a is a drive rocker arm 2 in cooperation with the valve spring 26 _1.
Since 2 is swung up and down, the first driven rocker arm 23 ₁ connected to it also swings at the same time to open and close the first exhaust valve 6 ₁ , but the second driven rocker arm 23 _{2 in} the free state is compatible. Since it comes into sliding contact with the rest cam 20b,
The second exhaust valve 6 ₂ is stopped in the closed state.

Further, as shown in FIG.
Is supplied, the first piston 31 ₁Receives that hydraulic pressure
Move the connecting pin 29 to the second connecting position to drive the rocker.
The arm 22 is replaced with the second driven rocker arm 23.₂When linked to
Together, the first driven rocker arm 23₁Free. this
If the camshaft 20 is rotating in such a state,
The operating cam 20a is the valve spring 26₂Driven in collaboration with
The locker arm 22 and the second driven rocker arm 23₂Rocking
Let the second exhaust valve 6₂Will be opened and closed.
First driven rocker arm 23 in a free state₁Corresponds to
Since it comes into sliding contact with the rest cam 20b, the first exhaust valve 6₁Close the valve
It will be paused in the state.

The first and second exhaust valves 6 ₁ , 6 ₂ as described above
The operating and rest conditions of are set according to the table below.

[0025]

[Table 1]

However, T ₁ ... Outlet temperature of the adsorption trapper 15 detected by the first temperature sensor 17.

T ₂ ... Outlet temperature of the catalytic converter 16 detected by the second temperature sensor 18.

Small engine load: A state in which the engine speed Ne is 3000 rpm or less and the boost pressure P _B is less than -300 mmHg.

Large ... Ne at 3000 rpm or more and P
_B is equivalent to -300 mmHg or more.

Next, the operation of the first embodiment will be described.

When the engine is in operation, if T ₁ is less than 140 ° C., the first exhaust valve 6 ₁ is in the operating state and the second exhaust valve 6 ₂ is in the resting state regardless of the load. The exhaust gas discharged from the chamber 2 is discharged to the first exhaust port 10 ₁ , collected by the first exhaust manifold 11 and introduced into the adsorption trapper 15, and the HC in the exhaust gas is absorbed by the HC adsorbent in the intake trapper 15. To be done. The exhaust gas from which HC has been removed in this way then moves to the exhaust pipe 13 and heats it while passing through the catalytic converter 16.

The temperature of the adsorption trapper 15 is raised by the heat of the exhaust gas, and when T ₁ becomes 140 ° C. or higher, HC is desorbed from the adsorbent 14 of the adsorption trapper 15. In this case, if the engine load is small, the operating state of the first exhaust valve 6 ₁ and the resting state of the second exhaust valve 6 ₂ do not change, and therefore the HC desorbed from the adsorption trapper 15 is discharged to the first exhaust port 10 _1. The exhaust gas is introduced into the catalytic converter 16 together with the exhaust gas and purified there. In this way, the HC adsorbent in the adsorption trapper 15 is regenerated.

Further, in this case, when the engine load is large, the first exhaust valve 6 ₁ is switched to the resting state and the second exhaust valve 6 ₂ is switched to the operating state. It is collected in the second exhaust manifold 12 via the exhaust port 10 ₂ and introduced into the catalytic converter 16 in the exhaust pipe 13. By the way, since the exhaust gas when the engine load is large has a relatively high temperature and a large amount, it effectively raises the temperature of the catalytic converter 16 and contributes to its activation. As a result, HC, CO, and NOx in the exhaust gas are effectively removed, and the durability of the adsorption trapper 15 is secured.

When T ₂ exceeds 300 ° C., the catalytic converter 16 is completely activated. In this case, regardless of the engine load, the first exhaust valve 6 ₁ is at rest and the second exhaust valve 6 ₁ is at rest.
Since the exhaust valve 6 ₂ is maintained in the operating state, the exhaust gas of each combustion chamber 2 is collected in the second exhaust manifold 12 via the second exhaust port 10 ₂ and purified by the catalytic converter 16 in the exhaust pipe 13. . Moreover, the second operating state
Since the exhaust valve 6 ₂ is formed to have a larger diameter than that of the first exhaust valve 6 _{1 in} the rest state, even if the flow rate of exhaust gas increases, the back pressure can be suppressed from increasing and the engine output can be improved. .

On the other hand, since the adsorption trapper 15 does not introduce exhaust gas, it is possible to avoid excessive temperature rise and maintain durability.

By the way, the first exhaust manifold 11 is
When the temperature of the adsorption trapper is low, each part can be formed to have a small diameter in accordance with a relatively small exhaust gas flow rate, whereby the heat mass can be reduced, the temperature drop of exhaust gas can be prevented as much as possible, and the catalytic converter 16 can be activated. .

In the first embodiment, the operating and rest conditions of the first and second exhaust valves 6 ₁ , 6 ₂ can be set as shown in the table below. The points that differ from Table 1 are marked with *.

[0038]

[Table 2]

Thus, T ₁ is 140 ° C. or higher, and T ₂
Is less than 300 ° C., regardless of the engine load, if the first exhaust valve 6 ₁ is in the rest state and the second exhaust valve 6 ₂ is in the operating state, the catalytic converter 16 is completely activated. The HC can be preserved in the adsorption trapper 15.

Further, a metal catalyst is attached to the adsorption trapper 15.
When using the one with the exhaust gas purification function,
₁Is over 140 ℃, T₂Above 300 ° C and
When the load is small, the connecting pin 29 is switched to the intermediate position.
Held in place, the first and second exhaust valves 6₁, 6₂Work together
Put in a state. In this way, the first exhaust port 10 ₁
Exhaust gas discharged from the inside of the first exhaust manifold 11
As it is purified, the burden on the downstream catalytic converter 16 is reduced.
Can be reduced.

Next, the second aspect of the present invention will be described with reference to FIGS.
Examples will be described.

In FIG. 8, the collecting pipes 11b and 12b of the first and second exhaust manifolds 11 and 12 are connected to each other via a communication pipe 40 on the upstream side of the adsorption trapper 15.
Between the communication pipe 40 and the first exhaust manifold 11, the first position A for blocking the communication pipe 40 and the collecting pipe 12b.
A switching valve 41 for rotating between the second position B that shuts off the suction trapper 15 at the inlet portion is provided. The first and second exhaust valve openings 4 ₁ and 4 ₂ and the caps of the first and second exhaust valves 6 ₁ and 6 ₂ are formed to have the same diameter. An exhaust valve operating system for the _first and second exhaust valves 6 ₁ and 6 ₂ will be described with reference to FIGS. 9 to 12.

In FIGS. 9 and 10, the exhaust valve operating system 1
On the cam shaft 20 of No. 9, one operating cam 20a and one rest cam 20b are formed for each combustion chamber 2. Rocker shaft 21
The first and second rocker arms 42 ₁ and 42 ₁ , whose tip portions respectively contact the valve heads of the first and second exhaust valves 6 ₁ and 6 ₂ .
42 ₂ are pivotally supported adjacent to each other, and the operating cam 20 a and the rest cam 20 b are in sliding contact with the upper surfaces of the first and second rocker arms 42 ₁ and 42 ₂ .

The rocker arms 42 ₁ and 42 ₂ are provided with a connecting device 43 for connecting them to each other and releasing them from each other.

This connecting device 43 is used for the first rocker arm 4
A connecting pin 45 slidably fitted in the first guide hole 44 ₁ of 2 ₁ and a piston 46 slidably fitted in the second guide hole 44 ₂ of the second rocker arm 42 ₂ . The connecting pin 45 has a non-connecting position (FIG. 11) where one end face is aligned with the boundary surface between the adjacent guide holes 44 ₁ and 44 ₂ and a connecting position (Fig. 11) where one end is projected into the second guide hole 44 ₂ . It is adapted to move between a 12), its non-coupling position is restricted by the end portion of the connecting pin 45 to the first guide hole 44 ₁ of the stepped portion 44a abuts the coupling position, the drive Pin 45
The piston 46 abutting against the step portion 44 of the second guide hole 44 ₂
It is regulated by contacting b.

[0046] The second guide hole 44 _2, return biasing the connecting pin 45 through the piston 46 in the uncoupled position the spring 47
Is reduced. Also in the second guide hole 44 _2, connecting pins 4
A hydraulic chamber 48 facing the end surface of 5 is defined.
Is selectively connected to a hydraulic pressure source or an oil reservoir by a control valve (not shown) via an oil passage 34 in the rocker shaft 21. Further, a vibration-proof spring 49 having a weaker force than the return spring 47 is contracted in the hydraulic chamber 48.

Thus, as shown in FIG. 11, the hydraulic chamber 48
Is released to the oil sump, the connecting pin 45 moves to the non-connecting position by the elastic force of the return spring 47, and the rocker arms 42
₁ and 42 ₂ are made independent. If rotates the cam shaft 20 in such a state, the first rocker arm 42 ₁ for opening and closing the first exhaust valve ₆₁ swings up and down by actuating cam 20a and the valve spring 26 ₁ cooperation However, since the second rocker arm 42 ₂ is in sliding contact with the pause cam 20b and does not swing, the second exhaust valve 6 ₂ is paused in the closed state.

Further, as shown in FIG. 12, when the hydraulic pressure is supplied to the hydraulic chamber 48, the connecting pin 45 receives the hydraulic pressure and moves to the connecting position to connect the rocker arms 42 ₁ and 42 ₂ to each other. If the cam shaft 20 is rotating in such a state, both the rocker arms 42 ₁ and 42 ₂ are simultaneously swung up and down by the cooperation of the actuating cam 20 a and the valve springs 26 ₁ and 26 ₂ , so that both exhaust valves are released. 6 ₁ and 6 ₂ are opened and closed.

The first and second exhaust valves 6 ₁ , 6 ₂ as described above
The operating and resting conditions and the switching conditions of the switching valve 41 are set according to the table below.

[0050]

[Table 3]

However, A ... The position of the switching valve 41 where the communication pipe 40 is cut off.

B ... Switching valve 41 in which the collecting pipe 11b of the first exhaust manifold 11 is shut off at the inlet of the adsorption trapper 15
Position of.

The other structure is the same as that of the previous embodiment. In the figure, the parts corresponding to those of the previous embodiment are designated by the same reference numerals.

According to the second embodiment, the same effects as those of the first embodiment can be obtained, and when the engine load becomes large, the first and second exhaust valves 6 ₁ , 6 ₂ are simultaneously operated, The back pressure can be reduced and the output can be improved.

In the second embodiment, the operating and deactivating conditions of the first and second exhaust valves 6 ₁ and 6 ₂ and the switching condition of the switching valve 41 can be set as shown in the table below. The points that differ from Table 2 are marked with *.

[0056]

[Table 4]

Thus, T ₁ is 140 ° C. or higher and T ₂ is 30.
When the temperature is below 0 ° C and the engine load is small, the first
If the switching valve 41 is switched to the second position B while the operating state of the exhaust valve 6 ₁ and the resting state of the second exhaust valve 6 ₂ are maintained, the adsorption trapper 15 is operated until the catalytic converter 16 is completely activated. HC can be preserved.

When a metal catalytic converter is attached to the adsorption trapper 15 to provide an exhaust gas purification function, T ₁ is 140 ° C. or higher, T ₂ is 300 ° C. or higher,
Also, when the engine load is small, both exhaust valves 6 ₁ , 6 ₂
The switching valve 41 is returned to the first position A while maintaining the operating state of. By doing so, the exhaust gas discharged from the first exhaust port 10 ₁ is purified in the first exhaust manifold 11, so that the burden on the downstream catalytic converter 16 can be reduced.

In each of the above embodiments, various design changes can be made without departing from the gist of the present invention. For example, the number of exhaust valves may be three or more for each combustion chamber.

[0060]

As described above, according to the first feature of the present invention, the branch pipe of the first exhaust manifold is provided at the outer end of the first exhaust port of each combustion chamber, and the outer end of the second exhaust port is provided at the outer end of the second exhaust port. The branch pipes of the second exhaust manifold are connected to each other, and the collecting pipes of both exhaust manifolds are connected to a common exhaust pipe,
An adsorbing trapper that adsorbs HC at low temperature is provided in the collecting pipe of the first exhaust manifold, and a catalytic converter is provided in the exhaust pipe. When the adsorbing trapper has a low temperature, the first exhaust valve is operated and the second exhaust valve is operated. So that the exhaust gas of each combustion chamber mainly flows to the first exhaust manifold ,
The branch pipe of the first exhaust manifold is the second exhaust manifold.
Because it is formed in each section diameter smaller than the de branch pipe, the first exhaust manifold, immediately after engine start, at low temperatures the adsorption trapper, in accordance with the relatively low flow rate of the exhaust gas, in particular each section diameter of the branch pipe <br/> Can be formed to have a small heat mass, and therefore, the temperature of the exhaust gas that has passed through the first exhaust manifold and the adsorption trapper does not have to be greatly lowered, and the heat of the exhaust gas activates the catalytic converter early, The exhaust gas purification rate can be increased.

According to the second feature of the present invention, when the catalytic converter is at a high temperature, the first exhaust valve is stopped and the second exhaust valve is stopped.
Operate the exhaust valve to mainly discharge the exhaust gas from each combustion chamber to the second
Since to flow into the exhaust manifold, without providing a switching valve in the exhaust system, at a high temperature of the catalytic converter, the adsorption bets
It is possible to block the introduction of exhaust gas to the wrapper and ensure its durability.

Further, according to the third feature of the present invention, each fuel is
At the outer end of the first exhaust port of the baking chamber,
A branch pipe and a second exhaust manifold at the outer end of the second exhaust port.
Connect the two branch pipes of each
Connect each collecting pipe of the hold to a common exhaust pipe,
The manifold collecting pipe has an adsorption tray that adsorbs HC at low temperatures.
Wrapper and exhaust pipe via catalytic converter
Installed and activates the first exhaust valve when the temperature of the adsorption trapper is low.
The second exhaust valve is stopped together with the main exhaust gas of each combustion chamber.
Flow into the first exhaust manifold as
When the converter is hot, shut down the first exhaust valve and
By operating the second exhaust valve, mainly the exhaust gas of each combustion chamber
Since it was made to flow to the second exhaust manifold, the first exhaust
Immediately after the engine starts, the manifold is
At high temperature, the heat mass is small according to the relatively small exhaust flow rate.
Can be replaced by the first exhaust manifold
Increase the temperature of the exhaust gas that has passed through the shield and adsorption trapper.
The catalytic converter is driven by the heat of the exhaust gas.
Can be activated early and the exhaust gas purification rate can be increased.
It When the temperature of the catalytic converter is high, the exhaust system has a switching valve.
Even if it is not installed, the introduction of exhaust gas to the adsorption trapper can be blocked.
The durability of the catalyst
The second exhaust valve, which is in operation when the inverter is hot, is in the idle state.
Since it is formed with a larger diameter than the first exhaust valve of
Even if the amount increases, the increase in back pressure is suppressed and the engine output
You can go up. Further, according to the fourth feature of the present invention,
If so, the first exhaust manifold is attached to the outer end of the first exhaust port of each combustion chamber.
A branch pipe of the hold and a second pipe at the outer end of the second exhaust port.
While connecting the branch pipes of the exhaust manifold,
Connect each collecting pipe of both exhaust manifolds to a common exhaust pipe
However, the collecting pipe of the first exhaust manifold absorbs HC at low temperature.
Adsorption trapper to be worn and a catalytic converter on the exhaust pipe
The interposed respectively between the first and second exhaust manifold, and their collection tube communicating pipe which communicates with each other provided on the upstream side of the adsorption trapper, between the communicating pipe and the first exhaust manifold, the communicating pipe A switching valve for switching between a first position for shutting off and a second position for shutting off the collecting pipe of the first exhaust manifold on the inlet side of the adsorption trapper is provided, and the first exhaust valve is activated when the temperature of the adsorption trapper is low. With this, the second exhaust valve is stopped while the switching valve is switched to the first position, and when the catalytic converter is hot, both the first and second exhaust valves are operated, while the switching valve is switched to the second position. , First
The exhaust manifold is equipped with an adsorption trapper immediately after the engine starts.
When the temperature is low, the heat
It can be small and therefore the first exhaust
The temperature of the exhaust gas that has passed through the Nihold and the adsorption trapper
It does not need to be lowered significantly, and the heat of the exhaust gas causes the catalyst converter to
Data can be activated early and the exhaust gas purification rate can be increased.
Wear. Further, when the temperature of the catalytic converter is high, the back pressure can be reduced by operating the first and second exhaust valves to achieve high output, and the introduction of exhaust gas to the adsorption converter can be blocked to ensure its durability. You can

[Brief description of drawings]

FIG. 1 is a bottom view of a cylinder head and an intake / exhaust system of an engine according to a first embodiment of the present invention.

FIG. 2 is a plan view of an exhaust valve operating system of the engine.

3 is a sectional view taken along line 3-3 of FIG.

4 is a sectional view taken along line 4-4 of FIG.

5 is a sectional view taken along line 5-5 of FIG.

6 is a sectional view taken along line 6-6 of FIG.

FIG. 7 is a sectional view similar to FIG. 6, showing an operating state of the connecting pin.

FIG. 8 is a bottom view of a cylinder head and an intake / exhaust system of an engine according to a second embodiment of the present invention.

FIG. 9 is a plan view of an exhaust valve operating system for the engine.

10 is a sectional view taken along line 10-10 of FIG.

11 is a cross-sectional view taken along line 11-11 of FIG.

FIG. 12 is a sectional view similar to FIG. 10, showing an operating state of the connecting pin.

[Explanation of symbols]

2 ... Combustion chambers 6 ₁ and 6 ₂ 1st and 2nd exhaust valves 10 ₁ and 10 ₂ 1st and 2nd exhaust ports 11 ... 1st exhaust manifold 11a ... Branch pipe 11b ... Collecting pipe 12 ... Second exhaust manifold 12a ... Branch pipe 12b ... Collecting pipe 13 ... Exhaust pipe 15 ... Adsorption trapper 16 ... -Catalytic converter 40 ...- Communication pipe 41 ...- Switching valve A ... First position of switching valve B ... Second position of switching valve

Continuation of front page (51) Int.Cl. ⁷ Identification code FI F01N 3/08 ZAB F01N 3/08 ZABA F02D 43/00 301 F02D 43/00 301T 301Z (58) Fields investigated (Int.Cl. ⁷ , DB) (Name) F01N 3/08-3/24 F01L 13/00 F02D 43/00

Claims (4)

(57) [Claims] 1. A first and second exhaust port (10 ₁ , 10 ₂ ) for each combustion chamber (2), the inner end of which is opened to the chamber,
First and second exhaust valves (6 ₁ , 6) for individually opening and closing these
₂ ), the branch pipe (11a) of the first exhaust manifold (11) is provided at the outer end of the first exhaust port (10 ₁ ) of each combustion chamber (2), and the second exhaust port (10) is also provided. ₂ ) The branch pipe (12a) of the second exhaust manifold (12) is connected to the outer end of the second exhaust manifold (12), and the collecting pipes (11b, 12b) of both exhaust manifolds (11, 12) are shared by the common exhaust pipe (13). Connect to
The collecting pipe (11b) of the first exhaust manifold (11) is provided with an adsorption trapper (15) for adsorbing HC at low temperature, and the exhaust pipe (13) is provided with a catalytic converter (16). When the temperature of 15) is low, the first exhaust valve (6
₁₎ by resting the second exhaust valve (6 ₂₎ actuates the, to flow exhaust gas mainly first exhaust manifold (11) of each combustion chamber (2), the first exhaust manifold
The branch pipe (11a) of (11) is the second exhaust manifold.
The diameter of each part is smaller than that of the branch pipe (12a) of (12).
Characterized in that that the exhaust purification device of an engine. 2. A pump of Claim 1, at a high temperature of the catalytic converter (16), the first exhaust valve (6 ₁₎
And the second exhaust valve (6 ₂ ) is activated,
An exhaust emission control device for an engine, characterized in that exhaust gas from each combustion chamber (2) is made to flow mainly into a second exhaust manifold (12). 3. For each combustion chamber (2), an inner end is opened in the chamber.
First and second exhaust ports (10 ₁ , 10 ₂ ) for
First and second exhaust valves (6 ₁ , 6) for individually opening and closing these
₂ ) and an engine provided with the first exhaust port (10 ₁ ) of each combustion chamber (2)
1 Connect the branch pipe (11a) of the exhaust manifold (11) to
A second exhaust manifold is attached to the outer end of the second exhaust port (10 ₂ ).
When connecting the branch pipes (12a) of the field (12) respectively
Both collecting pipes of both exhaust manifolds (11, 12)
Connect (11b, 12b) to the common exhaust pipe (13),
In the collecting pipe (11b) of the first exhaust manifold (11)
The adsorption trapper (15) that adsorbs HC at low temperature is discharged again.
Each of the trachea (13) is connected with a catalytic converter (16).
Mounted, and when the adsorption trapper (15) is at a low temperature, the first exhaust valve
Operate (6 ₁ ) and suspend second exhaust valve (6 ₂ ).
The exhaust gas of each combustion chamber (2) is mainly used for the first exhaust gas
Pour into the Nihold (11) and use the catalyst converter.
When the temperature of the motor (16) is high, the first exhaust valve (6 ₁ ) is stopped.
And the second exhaust valve (6 ₂ ) is activated,
The exhaust gas of (2) is mainly used for the second exhaust manifold (1
2) and the second exhaust valve (6 ₂ ) is
Characterized in that it is formed with a larger diameter than the valve (6 ₁ ),
Engine exhaust purification device. 4. For each combustion chamber (2), an inner end is opened in the chamber.
First and second exhaust ports (10 ₁ , 10 ₂ ) for
First and second exhaust valves (6 ₁ , 6) for individually opening and closing these
₂ ) and an engine provided with the first exhaust port (10 ₁ ) of each combustion chamber (2)
1 Connect the branch pipe (11a) of the exhaust manifold (11) to
A second exhaust manifold is attached to the outer end of the second exhaust port (10 ₂ ).
When connecting the branch pipes (12a) of the field (12) respectively
Both collecting pipes of both exhaust manifolds (11, 12)
Connect (11b, 12b) to the common exhaust pipe (13),
In the collecting pipe (11b) of the first exhaust manifold (11)
The adsorption trapper (15) that adsorbs HC at low temperature is discharged again.
Each of the trachea (13) is connected with a catalytic converter (16).
And a communication pipe (40) that connects the collecting pipes (11b, 12b) to each other upstream of the adsorption trapper (15) between the first and second exhaust manifolds (11, 12). Communication pipe (40) and first exhaust manifold (1
1) between the first position (A) for shutting off the communication pipe (40) and the second position (B) for shutting off the collecting pipe (11b) of the first exhaust manifold (11) at the inlet side of the adsorption trapper (15). )
A switching valve (41) for switching between and is provided, and when the adsorption trapper (15) is at a low temperature, the first exhaust valve (6 ₁ ) is operated and the second exhaust valve (6 ₂ ) is stopped while switching is performed. The valve (41) is switched to the first position (A), and when the catalytic converter (16) is at a high temperature, the first and second exhaust valves (6 ₁ , 6 ₂ )
An exhaust gas purifying apparatus for an engine, characterized in that the switching valve (41) is switched to the second position (B) while operating both.