KR100366255B1 - Exhaust system to improve output of engine - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is to provide an exhaust device which prevents a decrease in engine output by reducing the back pressure in normal conditions and rapid acceleration operation conditions in which the engine is warmed up. In the exhaust system,

An MCC catalytic converter connected to the exhaust manifold and equipped with a catalyst having a straight passage through which exhaust gas flows;

A first valve for opening and closing the straight passage;

A UCC catalytic converter installed in the middle of the exhaust pipe behind the MCC catalytic converter;

First and second branch pipes branched from exhaust pipes connected to the rear of the UCC catalytic converter;

A second valve operative to selectively open and close said first and second branch pipes;

A silencer connected to the first branch pipe; And controlling the operation of the first valve to block the central straight passage during cold start of the engine to allow the exhaust gas to pass through the catalyst, and to open the central straight passage during warm-up operation, and to operate the first valve during rapid acceleration operation of the engine. And an electronic control device for blocking the branch pipe, opening the second branch pipe, and controlling the operation of the second valve to open the first branch pipe and to shut off the second branch pipe during normal operation. It features.

Description

Exhaust system to improve output of engine

The present invention relates to an exhaust apparatus that can improve engine performance by reducing exhaust resistance of exhaust gases emitted from an engine.

As shown in FIG. 4, the combustion gas in the cylinder 20 is discharged to the atmosphere via the cylinder head 21, the exhaust manifold 22, and the exhaust pipes 23, 24, 25.

However, since the exhaust gas exhausted from the engine is high temperature, high speed, and high pressure, when the exhaust gas is discharged as it is, noise is greatly generated. Thus, a silencer 26 is installed to lower the temperature and pressure of the exhaust gas, thereby reducing exhaust noise.

In addition, because the exhaust gas ln CO, HC, NOx, etc. toxic gases are included in a large amount it when emits it as the standby pollute the environment and lead to various problems, such as to cause respiratory disease CO ₂ harmless these noxious gas The catalytic converters 27 (UCC) for conversion, reduction and discharge into H ₂ O and N ₂ are connected in the middle of the exhaust pipes 23 and 24.

However, 80-90% of the exhaust gas emissions are generated at the start of the engine before the engine warms up, whereas the catalytic converter 27, UCC is activated when the engine is warmed up and stabilized in the theoretical performance ratio range. Therefore, another catalytic converter 28 (MCC) is provided near the exhaust manifold 22 separately from the catalytic converter 27 (UCC).

In this way, the dual catalytic converters 27 and 28 are employed to purify the exhaust gas through the MCC catalytic converter 28 before warming up the engine, and to purify the gas through the UCC catalytic converter 27 after warming up. Consists of.

However, these silencers 26, MCC (28), UCC (27) is a necessary configuration, but because it is a resistor that prevents the smooth discharge of exhaust gas to increase the back pressure (low pressure) to reduce the engine output There is a problem.

In general, gasoline engines are known to reduce the engine output by 2-3PS when the back pressure increases by 100mmHg, and the resistance of the exhaust system is governed by the number of catalysts installed by the exhaust gas regulation and the silencer resistance for noise attenuation. However, exhaust gas emissions account for 80 ~ 90% before warm-up operation, and noise generation in high rotational area is not significant. UCC is sufficient for catalytic converter only when not in idling operation. Therefore, the MCC 28 and the silencer 26 under these driving conditions are only unnecessary resistances to increase the back pressure, which causes the engine output to fall.

Accordingly, the present invention has been proposed in view of the above, and an object thereof is to provide an exhaust device which prevents a decrease in engine output by reducing the back pressure during a normal condition and a rapid acceleration operation condition in which the engine is warmed up.

In order to achieve the above object, the present invention provides an exhaust device for exhausting exhaust gas combusted from an engine,

An MCC catalytic converter connected to the exhaust manifold and equipped with a catalyst having a straight passage through which exhaust gas flows;

A first valve for opening and closing the straight passage;

A UCC catalytic converter installed in the middle of the exhaust pipe behind the MCC catalytic converter;

First and second branch pipes branched from exhaust pipes connected to the rear of the UCC catalytic converter;

A second valve operative to selectively open and close said first and second branch pipes;

A silencer connected to the first branch pipe; And controlling the operation of the first valve to block the central straight passage during cold start of the engine to allow the exhaust gas to pass through the catalyst, and to open the central straight passage during warm-up operation, and to operate the first valve during rapid acceleration operation of the engine. And an electronic control device for blocking the branch pipe, opening the second branch pipe, and controlling the operation of the second valve to open the first branch pipe and to shut off the second branch pipe during normal operation. It features.

1 is a view showing an exhaust device for improving engine power according to the present invention;

2 is a control block diagram of the present invention;

3 is a flowchart art of the present invention

4 is a conventional exhaust device

※ Explanation of codes for main parts of drawing

1: Intake manifold 2, 3: Exhaust pipe

4: MCC catalytic converter 6: catalyst

7: center straight passage 8: first valve

9: UCC catalytic converter 10: 1st branch pipe

11: second branch pipe 14: cooling water temperature sensor

15 electronic control device 16 solenoid

17: Throttle Position Sensor 18: Solenoid

Hereinafter, the configuration and operation of the present invention will be described with reference to the accompanying drawings.

Fig. 1 is a view showing an exhaust device according to the present invention, and Fig. 2 is a control block diagram of the present invention, in which 1 is connected to a cylinder head to collect exhaust gas from each cylinder to exhaust pipes 2 and 3. It is an exhaust manifold to send.

The MCC catalytic converter 4 is connected to the exhaust manifold 1, the MCC catalytic converter 4 is for purifying exhaust gas during cold start of the engine, and the catalyst 6 is housed in the case 5. In the center of the catalyst 6, a straight passage 7 is formed.

The case 5 is provided with a first valve 8 for opening and closing the central straight passage 7. When the first valve 8 is rotated to become horizontal as indicated by a dotted line, the central straight passage 7 is provided. Will be blocked and will open when it is in a vertical position.

The exhaust pipe 2, which is connected to the rear of the MCC catalytic converter 4 and extends, is connected to a UCC catalytic converter 9 in which the purifying function is activated when the engine is warmed up and operated at the theoretical performance ratio.

The exhaust pipe 3 extending from the UCC catalytic converter 9 branches into the first and second branch pipes 10 and 11, and at the branching points, the first and second branch pipes 10 and 11. The 2nd valve 12 which selectively opens and closes is provided.

The silencer 13 is connected to the first branch pipe 10.

Hereinafter, an operation process of the present invention will be described based on the control block diagram of FIG. 2 and the flowchart art of FIG. 3.

When the engine is started, the cooling water temperature is detected from the cooling water temperature sensor 14, and the detected information is input to the electronic controller 15. The electronic controller 15 determines whether the cooling water temperature detected from the cooling water temperature sensor 14 has reached a normal value, for example, 85 ° C., which is a warm-up temperature (step a), and if it is not yet warmed up, the solenoid The linear valve 7 in the center of the catalyst 6 is blocked by driving 16 to make the first valve 8 horizontal (step b). When the central straight passage 7 is blocked, the exhaust gas passes through the catalyst 6, and is discharged after being purified by the catalyst 6.

However, if the detected cooling water temperature is a warm-up operation condition, the electronic controller 15 controls the solenoid 16 to drive the first valve 8 vertically to open the central straight passage 7 (step c). When the central straight passage 7 is opened, the exhaust gas exits backwards through the central straight passage 7 which is no exhaust resistance and is the shortest passage course, and the exhaust gas passes through the UCC catalytic converter 9 activated by warm-up operation. While being purged and discharged.

Next, the electronic controller 15 receives the information detected from the throttle position sensor 17 and determines whether the engine is in a normal operation state or a rapid acceleration operation state (step c).

The throttle position sensor 17 detects the opening angle of the throttle valve and detects the valve opening angle change amount when the accelerator pedal is suddenly pressed while the throttle valve is suddenly opened, and applies it to the electronic controller 15 from this information. If it is determined that the state is suddenly accelerated, the solenoid 18 is driven to rotate the second valve 12 to block the first branch pipe 10 and to open the second branch pipe 11 (step e). ).

Accordingly, the exhaust gas passing through the UCC catalytic converter 9 is discharged through the second branch pipe 11 without passing through the muffler 13 under the sudden acceleration condition and without any exhaust resistance. The silencer under the rapid acceleration condition as described above. When the exhaust gas is directly discharged through the second branch pipe 11 without passing through 13, it is expected that a slightly louder noise is generated than under normal operating conditions, but the noise of the exhaust gas discharged through the second branch pipe 11. Can be sufficiently controlled by tuning the entire exhaust system (by increasing or decreasing the diameter of the pipe or increasing its length to reduce exhaust noise), and this will not be a major problem if the resulting exhaust noise does not exceed the noise limit. Of automobiles (passenger cars and small-sized freight cars) manufactured after January 1, 1996, in accordance with It is specified that the noise (dB) should be 100 dB or less. In the present invention, the exhaust noise generated when the exhaust gas passes through the second branch pipe 11 without passing through the silencer under rapid acceleration conditions (exhaust system) Tuned state), it was confirmed that approximately 90 ~ 98dB is detected.

On the other hand, if it is detected in the normal operation in the step (d), the electronic controller 15 drives the solenoid 18 to block the second branch pipe 11 and the first branch pipe 10 to open. By rotating the valve 12, the exhaust gas is discharged to the atmosphere after the noise is attenuated through the silencer 13 (step bar).

In the above-mentioned steps (e) and (f), when the start is turned off, the process is terminated.

According to the present invention as described above, the engine is allowed to pass through the MCC catalytic converter without resistance in the warm-up state, and the exhaust gas is discharged through the silencer during the rapid acceleration operation of the engine where the feeling of acceleration is prioritized. In addition, it is possible to improve engine output by reducing unnecessary exhaust resistance.

Claims (3)

In the exhaust device for exhausting the exhaust gas burned from the engine, An MCC catalytic converter connected to the exhaust manifold and equipped with a catalyst having a straight passage through which exhaust gas flows; A first valve for opening and closing the straight passage; A UCC catalytic converter installed in the middle of the exhaust pipe behind the MCC catalytic converter; First and second branch pipes branched from an exhaust pipe connected to the rear of the UCC catalytic converter; A second valve operative to selectively open and close said first and second branch pipes; A silencer connected to the first branch pipe; And controlling the operation of the first valve to block the central straight passage during cold start of the engine to allow the exhaust gas to pass through the catalyst, and to open the central straight passage during warm-up operation, and to control the first valve during rapid acceleration operation of the engine. And an electronic control device for blocking the branch pipe, opening the second branch pipe, and controlling the operation of the second valve to open the first branch pipe and to shut off the second branch pipe during normal operation. Exhaust system for improving engine power. The method of claim 1, And the first and second valves are solenoid operated valves. The method of claim 2, And the electronic control unit drives and controls the first and second valves based on information detected from the coolant temperature sensor and the throttle position sensor.