JPS5836173B2 - Haikigasujiyoukasouchi - Google Patents

Description

[Detailed description of the invention] The present invention relates to an exhaust gas purification device.

As a method to reduce nitrogen oxide (NOx), which is a harmful component in the exhaust gas emitted from internal combustion engines, there are two methods: using a mixture with a rich air-fuel ratio, or recirculating a portion of the exhaust gas to the intake system. It is known that it is effective to provide the exhaust system with a catalytic converter that operates in response to supply of secondary air.

The present invention aims to achieve a comprehensive exhaust gas purification effect by effectively combining these single methods while taking into account the operating conditions of the internal combustion engine. In an exhaust gas purification system that has an exhaust gas recirculation amount adjustment valve provided between the intake system and exhaust system of the engine, and a secondary air amount adjustment valve that controls the supply of secondary air to the exhaust system, The system, the exhaust gas recirculation amount adjustment valve, and the secondary air amount adjustment valve are selectively communicated with the intake system negative pressure or atmospheric pressure by the action of a control system that responds to changes in the intake system negative pressure. The present invention provides an exhaust gas purification device that purifies exhaust gas.

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

In FIG. 1, reference numeral 1 denotes an internal combustion engine, in which an intake pipe 2 is connected to a carburetor 4 having a throttle valve 5, and an exhaust pipe 3 is connected to a reduction catalytic converter 6 and an oxidation catalytic converter 7 connected thereto. Ru.

The carburetor 4 has a power system 10 having a pressure intake port 11.
is provided.

The intake pipe 2 and the exhaust pipe 3 are connected to an exhaust gas recirculation amount adjustment valve 20.
is connected to the ports 2' and 3' via the upstream side of the reduction catalytic converter 6 of the exhaust pipe 3 and the oxidation catalytic converter 7
Ports 6' and 7' provided on the upstream side of the air pump are communicated with the discharge side of an air pump (not shown) via a secondary air amount regulating valve 30.

The exhaust gas recirculation amount regulating valve 20 has an inlet port 122 and an outlet port 23, and communication between the two ports 22 and 23 is achieved by a valve body 24 that responds to the deformation of the diaphragm 25.

The diaphragm 25 separates a chamber 28 that opens to the atmosphere and a chamber 29 that is provided with a spring 26 that communicates with an outlet port 63 of a negative pressure regulating valve 60, which will be described later.

The secondary air amount adjusting valve 30 has an inlet port 31 and two outlet ports 32 and 33.
1 and another outlet port 32.

The diaphragm 35 separates a chamber 38 that opens to the atmosphere and a chamber 39 that is provided with a spring 36 that communicates with an outlet port 73 of a negative pressure regulating valve 70 that will be described later.

On the other hand, the negative pressure take-out port 8 provided in the intake pipe 2 is connected to an inlet chamber 83 of a negative pressure delay valve 8σ in which a check valve 81 and a throttle 82 are provided in parallel, a power system 10, and an exhaust gas recirculation amount adjustment valve 20. , and communicate with negative pressure regulating valves 50, 60, and 70, which are arranged in parallel and corresponding to the secondary air amount regulating valve 30.

These three negative pressure regulating valves have two inlet ports 51 and 52.
, 61 , 62, 71, 72 and one outlet port 53,
63, 73, and the switching of this inlet port is performed by the valve body 5 according to the deformation of the diaphragm 55, 65, 75.
4,64,74.

The diaphragm has springs 56, 66, 76, chambers 5γ, 67, 77 with ports, and chambers 58, 6 with only ports.
8 and 78.

The outlet chamber 84 of the negative pressure delay valve 80 is connected to the negative pressure regulating valves 50 and 60.
, 70 via an accumulator 85.

The chambers 58, 68, and γ8 communicate with the negative pressure extraction port 8.

The outlet port 53 of the negative pressure regulating valve 50 communicates with the pressure intake port 11 of the power system 10, the inlet port 52 communicates with the atmosphere, and the other inlet port 51 communicates with the negative pressure outlet port 8.

The outlet port 63 of the next negative pressure regulating valve 60 is connected to the chamber 29 of the exhaust gas recirculation amount regulating valve 20 as described above, and the inlet port 63 is connected to the chamber 29 of the exhaust gas recirculation amount regulating valve 20.
2 communicates with the negative pressure extraction port 8, and the other inlet port 61 communicates with the atmosphere.

The outlet port γ3 of the negative pressure regulating valve 70 communicates with the chamber 39 of the secondary air amount regulating valve 30, the inlet port 72 communicates with the negative pressure extraction port 8, and the other five inlet ports 71 communicate with the atmosphere.

Next, the effect will be explained.

When the change in the opening degree of the throttle valve 5 is small, the change in the negative pressure in the intake pipe 2 is small.

Therefore, the pressure differences between the chambers 57 and 58, 67 and 68, and 77 and 78 of the negative pressure regulating valves 50, 60, and 70 are small, and the valve bodies 54, 64, and 74 are moved to the inlet port by the force of the springs 56, 66, and 76. 52, 62, 72 are closed, and the other inlet ports 51, 6L71 and the outlet ports 53, 63, 73 are communicated with each other.

Therefore, the pressure intake port 11 of the power system 10 receives negative pressure in the intake pipe, the chamber 29 of the exhaust gas recirculation amount adjustment valve 20 receives atmospheric pressure, and the chamber 39 of the secondary air amount adjustment valve 30 receives the same high pressure. Air pressure is supplied.

As a result, the power system 10 does not operate, and the two regulating valves 20
, 30 are also closed by the force of the springs 26, 36.

In this case, therefore, secondary air is only supplied to port 7' from the air pump.

Next, when the opening degree of the throttle valve 5 changes greatly, that is, when the internal combustion engine accelerates, the negative pressure in the intake pipe 2 changes greatly.

This negative pressure change is supplied to the negative pressure regulating valves 50, 60, and 70, and due to the action of the negative pressure delay valve 80, the chambers 58,
68, 78 and the chambers 57, 67, 77, the valve bodies 54, 64, γ4 close the inlet port 5L6L71 against the force of the springs 56, 66, 76, and close the other inlet ports. 52, 62, 72 and outlet ports 53, 63, 73 are communicated with each other.

For this reason, atmospheric pressure is supplied to the power system 10 to push fuel to the carburetor 4 and enrich the air-fuel mixture.

Negative pressure is supplied to the chamber 29 of the regulating valve 20 so that the valve body 24 opens against the force of the spring 26, allowing the exhaust gas to be recirculated.

Negative pressure is also supplied to the chamber 39 of the regulating valve 30, and the valve body 34 opens against the force of the spring 36, supplying secondary air to the two ports 6' and 7', respectively, and discharging the exhausted nitrogen. Oxide NO
The catalytic converters 6 and 7 render X harmless.

Accumulator 85 together with diaphragm 82 defines the delay time.

FIG. 2 shows another embodiment.

Instead of newly using the power system control valve 90, only one negative pressure control valve is required.

The same numbers as in FIG. 1 are given to common parts.

To explain the structure of only the different parts, the inlet port 51 of the negative pressure control valve 50 opens to the atmosphere.

Inlet port 52 communicates with negative pressure outlet port 8 .

The outlet port 53 communicates with the respective chambers 99, 29, and 39 of the power system control valve 90, the exhaust gas recirculation amount adjustment valve 20, and the secondary air amount adjustment valve 30.

In the power system control valve 90, an inlet port 91 communicates with the negative pressure take-out port 8, an inlet port 92 communicates with the atmosphere, and an outlet port 93 communicates with the power system pressure intake port 11.

When the change in the opening degree of the throttle valve 5 is small, the negative pressures in the chambers 57 and 58 of the negative pressure adjustment valve 50 are almost equal, so the power system control valve 90, exhaust gas recirculation amount adjustment valve 201, and secondary air amount adjustment Atmospheric air is supplied to each chamber 99, 29, 39 of valve 30 from inlet port 51.

Therefore, at this time, secondary air is only supplied from the air pump to port 7'.

However, when the opening degree of the throttle valve 5 changes greatly, that is, when the internal combustion engine accelerates, the valve body 54 is pushed down by a small negative pressure in the chamber 58 of the negative pressure control valve 50, and the inlet port 52 and the outlet port 53 communicate with each other. .

As a result, the power system 10 is activated, the exhaust gas is recirculated through port 2', and secondary air is supplied through port 6'.

As described above, according to the present invention, by supplying a rich air-fuel mixture during acceleration and recirculating a portion of the exhaust gas, the generation ratio of nitrogen oxides (NOx) in the exhaust gas is reduced, and Since the generated nitrogen oxides NOx can be treated with the catalytic converter by supplying secondary air, purification of the exhaust gas is achieved.

Furthermore, in the low load range of the internal combustion engine, the oxidation catalytic converter only acts slightly, and the engine maintains proper operation.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an embodiment based on the present invention, and FIG. 2 is another embodiment. 1...Internal combustion engine, 2...Intake system, 3.
...exhaust system, 4...carburizer, 10...
...Power system, 20...Exhaust gas recirculation amount adjustment valve, 30...Secondary air amount adjustment valve, 50,60
,70,80...control system.

Claims (1)

[Claims] 1. The power system of the carburetor, the exhaust gas recirculation amount adjustment valve installed between the intake system and the exhaust system of the internal combustion engine, and the secondary air amount adjustment valve that controls the supply of secondary air to the exhaust system. In the exhaust gas purification device, the power system, the exhaust gas recirculation amount adjustment valve, and the secondary air amount adjustment valve are adjusted to an intake system negative pressure or atmospheric pressure, and a control system that responds to changes in the intake system negative pressure. An exhaust gas purification device characterized in that exhaust gas purification is performed by selectively communicating with each other by the action of the following.