JPS63235617A - Exhaust gas cleaning device for internal combustion engine - Google Patents

Abstract

PURPOSE:To enable the efficient recovery of unburnt HC by providing a bypass exhaust gas cooling means and a condensed ingredient reservoir for condensing an unburnt HC ingredient in order an exhaust bypass which is branched off of an exhaust passage, and introducing said unburnt HC ingredient into an intake passage after warming up an engine. CONSTITUTION:An exhaust bypass 5 is branched off of an exhaust passage 2 on the lower course side of a catalyst converter 3, and a selector valve 14 which is switched so as to open a bypass 5 side when the catalyst converter 3 is judged in an inactive condition under a low intake temp., is provided in its branched part 5a. And, a cooling pipe 30 which consists of plural cooling passages 30a-30c and which is cooled by an air flow is provided midway in the exhaust bypass 5 to cool exhaust gas in order condense an unburnt HC ingredient in the exhaust gas. And the condensed ingredient is collected in a condensed ingredient reservoir 30b and, after warming up an engine, a liquid type unburnt HC in the reservoir 30b is mixed with air introduced from a vent hole 7 through a check valve 8 and, then, fed into an intake passage 19 on the upper course side of a throttle valve 23 through a passage 33.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an exhaust purification device for treating unburned HC discharged from an internal combustion engine.

In vehicles equipped with conventional technology gasoline engine, diesel engine, etc.
Generally, a catalytic converter is installed in the exhaust passage in order to reduce unburned 11c emissions.

In addition, in spark ignition engines that use fuel mixed with alcohol or gasoline, a large amount of unburned HC is emitted when the engine is cold. An adsorption device 6 for absorbing unburned IIc is provided downstream.

To explain this exhaust purification device, an exhaust bypass passage 5 is provided between a catalytic converter 3 provided in an exhaust passage 2 of an engine body 1 and a muffler 4, and unburned 1-IC is adsorbed in the middle of the exhaust bypass passage 5. An adsorption device 6 is provided, and an unburnt 1-(
A check valve 8 that allows air to flow into the adsorption device 6 through the vent hole 7 during purging of C, and a check valve 16 that prevents exhaust from flowing back into the exhaust bypass passage 5 from the downstream connecting portion 2a of the exhaust passage 2. 9 is interposed.

When cold, as shown in FIG. 4, the three-way solenoid valve 11 is switched to the atmospheric side by a command from the control device 10, atmospheric pressure is introduced into the diaphragm chamber 13 of the diaphragm device 12, and the switching valve 1
By opening 4, exhaust gas from the catalytic converter 3 is guided to the exhaust bypass passage 5, and unburned HC that could not be trapped by the catalytic converter 3 is adsorbed in the adsorption device 6.

After warming up 11, the exhaust gas is not passed through the exhaust bypass passage 5 but through the exhaust passage 2 to oxidize and remove unburned HC from the thermally activated catalytic converter 3r, and remove unburned HC adsorbed by the adsorption device 6 during the cold period. By opening the bimetallic vacuum switching valve (BVSV) 16, burned HC is sucked from the purge bows 1 and 21 through the passage 17 into the intake passage 19 upstream of the surge tank 18, and this unburned HC is transferred together with air into the combustion chamber 20.
Burn it.

Problems to be Solved by the Invention However, in the conventional exhaust purification device, as shown in FIG. 4, an adsorption filter 2 for adsorbing unburned HC in the exhaust gas
2, there is a problem in that the back pressure of the exhaust gas due to the adsorption filter 22 increases and the output of the FjM jump decreases.

The present invention was made to solve these problems, and aims to recover unburned LIC in exhaust gas without using an adsorption filter.

Means for Solving the Problems In order to achieve the above-mentioned [1], the internal combustion exhaust gas purification device of the present invention is provided with an exhaust bypass passage branching from the exhaust passage, and a switching valve is interposed in this branching part. At the same time, a cooling means for cooling the bypass exhaust gas is provided in the exhaust bypass passage, a condensed component reservoir for condensing unburned HC components in the exhaust gas is provided in the exhaust bypass passage downstream of the cooling means, and the unburned HC components are stored in the condensed component reservoir. Purge the unburned HC components after warming up]・
The structure is such that the air is introduced into the intake passage.

Effect When the temperature of IRI3Il is low, the exhaust gas flows through the exhaust bypass passage and is cooled by the cooling means, and the unburned HC in the exhaust gas is condensed and stored in the condensate reservoir, and the exhaust gas from which the unburned HC has been removed flows through the exhaust passage. will be returned to.

When the engine is warmed up, the liquid unburned 1-IC stored in the condensed component reservoir is atomized together with air and introduced into the intake passage through the purge port.

Therefore, unburned HC in the exhaust gas is recovered when the engine is at low temperature, and the recovered unburned IC is introduced into the intake passage after the engine is warmed up.
1G is reduced.

Example Embodiments of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment in which the present invention is applied to a gasoline engine. In FIG. 1, components that are substantially the same as those in FIG. 4 are designated by the same symbol q.

The flow of the intake air introduced into the intake passage 19 from the air cleaner 21 is controlled by the throttle valve 23, and the intake air passes through the surge tank 18 from the intake boat 24 to the combustion chamber 2.
It is sucked into zero and burned.

Exhaust gas discharged from the exhaust boat of the combustion chamber 20 flows through the exhaust passage 2 via the catalytic converter 3. The housing 3a of the catalytic converter 3 is provided with a temperature sensor 25 for detecting the temperature of the catalytic converter 3.

An exhaust bypass passage 5 branches off from the exhaust passage 2 on the downstream side of the catalytic converter 3, and merges into the exhaust passage 2 roughly downstream.

At the branch part 5a between the exhaust passage 2 and the exhaust bypass passage 5,
A switching valve 14 is provided to switch the exhaust flow path, and the switching valve 14
The diaphragm device 12 selectively switches the flow path of (1 air) to the main exhaust passage 2a or the exhaust bypass passage 5. Atmospheric pressure or negative pressure in the intake pipe in the rigid tank 1@8 is introduced.In the middle of the passage 26, when the three-way solenoid valve 11 is switched to the negative pressure side in the intake pipe, air in the diaphragm chamber 13 is introduced. A check valve 28 is provided to draw air into the intake pipe and to prevent air from flowing into the diaphragm chamber 13 when the negative pressure in the intake pipe is small.

A cooling pipe 30 as a cooling means is provided in the middle of the exhaust bypass passage 5, and the bypass exhaust gas that has passed through the cooling pipe 30 flows into a condensed component reservoir 31.

After the condensed exhaust components (mainly unburned HC) are removed in the condensed component reservoir 31, the exhaust gas that has been sufficiently cooled by the cold IJl pipe 30 is sent to the main stream via the check valve 9 by the downstream exhaust bypass passage 5b. It merges into the exhaust passage 2a.

The liquid unburned HC accumulated in the condensed component reservoir 31 is mixed with air introduced from the vent hole 7 through the check valve 8 after the engine is warmed up, and this mixture is passed through the bimetal vacuum comb switching valve (BVSV). ) 32 , the air is purged from the purge port 34 to the intake passage 19 upstream of the throttle valve 23 . When purging, selector valve 14
The entrance of the exhaust bypass passage 5 is closed.

Note that the cooling pipe 30 includes a plurality of cooling passages 30a.

30b and 30G, and a cooling fan (not shown) is provided around the passage.

Next, the operation of the three-way solenoid valve 11 and the BVSV 32 will be explained. For example, the three-way solenoid valve 11 and the BVSV 32 are
V32 is controlled. Signals from the intake air temperature sensor 4) 45 and catalyst temperature sensor 25 are input to the exhaust flow path switching valve control means 41 of the control device 40, and signals from the intake air temperature sensor 4) 45 and the catalyst temperature sensor 25 are input to the purge flow path switching valve control means 42. 45, catalyst temperature sensor 25, engine water temperature sensor 46, and engine speed sensor 4J47 are input. A three-way solenoid valve drive circuit 43 is driven by a command from the exhaust flow m switching valve control means 41, and the three-way solenoid valve 11 is controlled by this output. In addition, the BVSV is
The drive circuit 44 is driven, and this output causes [3VSV3
2 is controlled.

FIG. 3 is a flowchart 1- showing an example of the operation of the three-way solenoid valve 11 and the BVSV 32.

In the first step 51, the intake temperature Tin, the catalyst temperature Tca
t, engine water temperature Tw, and engine speed Q.

In the next step 52, it is determined whether or not the intake air m T in is 10°C or less, and if Tin≦10°C, it is considered that the temperature is low, and the process goes to the next step 53, where the catalyst temperature TCat is 2.
If Tcat≦200°C, it is determined that the catalytic converter 3 is in an inactivated state, and the process proceeds to the next step 54, where the BVSV 32 is closed, and at the next step 55, the three-way electromagnetic Switch the valve 11 to the negative pressure side. When the three-way solenoid valve 11 is switched to the negative pressure side, intake pipe negative pressure is introduced into the diaphragm chamber 13 from the passage 26, the diaphragm 12a pulls the iron 12C in the direction of the arrow against the spring 12b, and the switching valve 14 is bypassed and exhausted. Switch to the aisle side. As a result, the exhaust gas is cooled by the cooling means 30 in the middle of the exhaust bypass passage 5, and the unburned 11G component in the exhaust gas is condensed into the condensed component reservoir 31.

If it is determined in step 53 that the tR temperature cat>200° C., it is assumed that the catalytic converter 3 is in an active state, and the process proceeds to step 56. In step 56, the three-way solenoid valve 11 is set to the atmosphere side, atmospheric pressure is introduced from the passage 26 into the diaphragm chamber 13, the rond 12G is pushed up in the opposite direction of the arrow, and the inlet of the exhaust bypass passage 5 is closed with the switching valve 14. , the flow of exhaust gas is switched to the main exhaust passage 2a side.

In the next step 57, it is determined whether the engine water ITw is 60°C or higher, and if TV<60°C, this routine is ended, and if 1w560°C, it is considered that it has been warmed up.
Proceeding to step 58, it is determined whether the engine speed Q is 1200 rpm or more. At step 58, Q≧1
If it is 200 rpm, proceed to step 59 and BVSV
Open 32.

At this time, since intake pipe negative pressure is generated in the purge port 34, the intake pipe negative pressure is introduced into the condensed component [31] through the passage 33, which opens the check valve 8 and condenses air from the vent hole 7. A mixture of air and unburnt 11G is introduced into the component reservoir 31 and is sucked into the intake passage 19 from the purge port 34 via the 3VSV 32.

As described in detail, according to the present invention, by cooling the exhaust gas discharged when the engine is cold, unburned 1''G
Since this unburned HC component is re-burned in the air and Jt after warming up, it is possible to recover unburned [-10] even without installing an absorption filter, and it is possible to recover Fuel efficiency can be improved when the vehicle is operated for a long time, especially when the vehicle is not warmed up.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a control device used in the embodiment shown in FIG. 1, and FIG. 3 is a block diagram showing each embodiment of the invention shown in FIG. FIG. 4 is a flowchart showing the operation of the Benso Hyo, and is a schematic configuration diagram of a conventional example. 1... Engine body, 2... Exhaust passage, 3...
・Catalytic converter, 5...exhaust bypass passage, 7.
...Vent hole, 8...Check valve, 9...Check valve, 11...Three-way solenoid valve, 12...Diaphragm device, 14...Switching valve, 19...Intake passage, 2
3... Throttle valve, 30... Cooling (cooling means), 31... Condensed component reservoir, 32... Bimetal vacuum switching valve (
f3VsV), 34... Bargebo 1., 40... Control device.

Claims (1)

[Claims] An exhaust bypass passage is provided that branches from the exhaust passage, a switching valve is interposed in this branching part, and a cooling means for cooling the bypass exhaust is provided in the exhaust bypass passage, and a cooling means for cooling the bypass exhaust is provided in the exhaust bypass passage downstream of the cooling means. A condensed component reservoir for condensing unburned HC components is provided, and the unburned HC components stored in the condensed component reservoir are introduced into an intake passage together with air from a purge port after warming up. Device.