KR19980080270A - Method and apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine - Google Patents

Abstract

It is an object to improve the method of reducing the harmful substances in the combustion exhaust gas from an internal combustion engine so that the start-up time of the catalyst is shortened, thereby enabling the reduction of the harmful exhaust gas after the catalyst, particularly in the low temperature startup process.

A method and apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine, in particular an automobile internal combustion engine, in which a gas having a high oxygen content obtained from the atmosphere is supplied to an internal combustion engine by at least one membrane permeable only to oxygen molecules provided in the chamber, In order to shorten the start-up time of the catalyst and thereby improve the reduction of harmful exhaust gas after the catalyst, especially in the low temperature start-up process, the gas having a high oxygen content is incorporated into the intake air as a function of the operating point of the internal combustion engine. It is proposed to do it.

Description

Method and apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine

The present invention relates to a hazardous substance in combustion exhaust gas from an internal combustion engine, in particular an automobile internal combustion engine, in which a gas having a high oxygen (O ₂ ) content obtained from the atmosphere is supplied to an internal combustion engine by at least one membrane permeable only to oxygen molecules provided in the chamber. It relates to a reduction method.

Apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine in which oxygen (O ₂ ) obtained by a membrane that is permeable only to oxygen molecules is supplied to the combustion exhaust gas, in a chamber provided in a bypass channel from German Patent No. And methods are already known.

By this enrichment of oxygen in the fresh air supplied to the engine, on the one hand, as the exhaust gas temperature rises, the catalyst start-up time, i.e. the elapsed time until the catalyst reaches its operating temperature and exerts its full action, is shortened. do. At the same time, bioemission of carbon monoxide (CO) and hydrocarbon (HC) is reduced as the conversion of fuel in the engine is improved. As the nitrogen content during combustion is reduced, the amount of nitrogen oxides to be treated by the catalyst in order to reduce environmental pollution is reduced.

It is known that about 80% of the total emissions of carbon monoxide (CO) and hydrocarbons (HC) in gasoline engines occur between the first 120 seconds after cold start. This cause is due to inadequate conversion of engine bioemissions by catalysts that have not yet reached operating temperature.

Therefore, the start-up time of the catalyst is shortened, thereby improving the method of reducing the harmful substances in the combustion exhaust gas from the internal combustion engine of the type described in the opening so that it is possible to reduce the harmful exhaust gas after the catalyst, especially in the low temperature start-up process. It is a subject of the present invention.

1 is a schematic diagram of a first embodiment of an apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine of the present invention;

Fig. 2 is a schematic diagram of a second embodiment of an apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine of the present invention.

Figure 3 is a schematic diagram of a third embodiment of an apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine of the present invention.

4 is a schematic view of a fourth embodiment of a device for reducing toxic substances in combustion exhaust gas from an internal combustion engine of the present invention.

Fig. 5 is a schematic diagram of a fifth embodiment of an apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine of the present invention.

Explanation of symbols for the main parts of the drawings

10: intake pipe

12: throttling valve

14, 15, 17: air filter

16: idling setter

20: bypass channel

21: thread

22, 34: check valve

23: entrance

24: blower

25, 32: exit

27: filtration gas side

30: membrane

M: Internal combustion engine

S1, S2, S3, S4, S5: Intake air flow

This problem is solved by incorporating a gas having a high oxygen content into the intake air as a function of an operating point of the internal combustion engine in the method of reducing harmful substances in combustion exhaust gas from an internal combustion engine of the type described in the opening paragraph.

By incorporating a gas having a high oxygen content as a function of the operating point, it is particularly advantageous that there is always a high oxygen content in the combustion gas when a high oxygen content is required based on the operating point.

It is advantageous for the gas with a high oxygen content to be incorporated into the intake air in one or more of the following operating states: cold start process, idling process, warm up process, partial load process. Experience has shown that in these operating states, extremely harmful emissions of carbon monoxide (CO) and hydrocarbon (HC) exist on the catalyst outlet side. It is possible to significantly reduce this exhaust gas by enriching the oxygen (O ₂ ) content during these operation processes. In addition, the exhaust gas temperature is increased by the enrichment of oxygen of fresh air supplied to the engine, whereby the catalyst can be operated early as the catalyst start-up time is shortened.

It is preferred that the enrichment of oxygen (O ₂ ) is in the range of 25 to 35 volume percent.

In addition, the present invention relates to an internal combustion engine, in particular an automobile, provided with at least one membrane which is arranged indoors and is capable of supplying the atmosphere and is permeable only to oxygen molecules in order to obtain a gas having a high oxygen (O ₂ ) content supplied to the internal combustion engine from the atmosphere. A device for reducing harmful substances in combustion exhaust gas from an internal combustion engine.

In this regard, an operation in order to generate an air flow having a high mass flow rate of variable oxygen (O ₂ ) by, for example, a hollow fiber membrane module which is already provided in an automobile, and to reduce its harmful substance emission gas. It is an object of the present invention to provide an apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine of the type described in the beginning, which supplies this air stream to intake air of an internal combustion engine as a function of point.

SUMMARY OF THE INVENTION The present invention is directed to a device for reducing harmful substances in combustion exhaust gas from an internal combustion engine of the type described in the beginning, wherein the chamber is disposed in a bypass channel disposed parallel to the intake pipe of the internal combustion engine, and the chamber is in an operating state of the internal combustion engine. That is, it is solved by being able to open and close in one or a plurality of processes of a low temperature start-up process, an idling process, a warm-up process and a partial load process.

By arranging the seal in an additional bypass channel arranged parallel to the intake pipe of the internal combustion engine, it is particularly advantageous that the enrichment of the intake air as a function of the operating state can be made simple. When the enrichment of the intake air is desired by oxygen, the bypass channel is always opened, thereby enabling the passage flow of the membrane that is permeable only to oxygen molecules provided in the bypass channel.

Purely in principle, the bypass channel can be opened in any way. It is advantageous that the bypass channel can be opened and closed via an idling setter.

Various arrangements can be considered with regard to the arrangement of the inlet and outlet of the seal. Advantageous embodiments have a design in which the inlet and outlet of the seal are arranged in a bypass channel such that the membrane is permeable in parallel flow, ie parallel to the flow direction of the intake air.

Another particularly advantageous embodiment which achieves an increase in efficiency is a design in which the inlet and outlet of the seal are arranged in a bypass channel such that the membrane is permeable in a countercurrent shape, ie in the opposite direction to the flow direction of the intake air. It is. Since the countercurrent permeation is thus performed over the entire length of the membrane, an optimum oxygen partial pressure drop can be achieved in advance by extremely efficient permeation of the membrane formed as a hollow fiber membrane, for example.

In particular, it is advantageous that a common air filter is provided for the intake pipe and the bypass channel in order to reduce contamination in the intake pipe and the bypass channel.

Another embodiment is designed such that separate air filters are provided for the intake pipe and the bypass channel, respectively.

In order to ensure sufficient airflow through the membrane, in some embodiments a startable blower is provided in the bypass channel as required, and the blower is designed to ensure a variable high oxygen partial pressure in some cases than the filtration gas side of the membrane. It is desirable to have.

At least one check valve is designed to be installed in the bypass channel to prevent backflow of air in the bypass channel.

Other features and advantages of the present invention will become apparent from the following description and drawings of some embodiments of the present invention.

A first embodiment of an apparatus for reducing harmful substances in combustion exhaust gas shown in FIG. 1 includes an intake pipe 10 in which an throttling valve 12 is disposed. The atmosphere is introduced into the intake pipe 10 by the negative pressure generated by the internal combustion engine (not shown) via the air filter 14. The bypass channel 20 is arranged parallel to the intake pipe 10, and a chamber 21 including the inlet 23 and the outlet 25 is disposed in the bypass channel 20.

The chamber 30 is provided with a membrane 30 that can permeate only oxygen molecules O ₂ . This membrane 30 is actually a bundle of hollow fiber membranes embedded in a synthetic resin, for example, on the inlet side and the outlet side thereof.

In the bypass channel 20, a check valve 22 for preventing backflow in the bypass channel 20 and a blower 24 capable of supplying the air flow generated under a somewhat high pressure to the membrane 30 are provided. . In addition to the (filtration gas) outlet 25 of the chamber 21, another outlet 32 of the chamber 21 is provided, and residual gas which is lean in oxygen exiting the inside of the membrane 30 from the outlet 32 flows out.

The bypass channel 10 arranged in parallel with the intake pipe 10 is advantageously controlled by, for example, motor control via the idling setter 16 and openable. This makes it possible to enrich the oxygen (O ₂ ) with the intake air supplied to the internal combustion engine as a function of the operating point.

The harmful substance reduction apparatus in the combustion exhaust gas from the internal combustion engine shown in FIG. 1 has the effect as described below.

After the atmosphere has passed through the common air filter 14 (see the flow of intake air shown by the arrows with the symbols S1, S2, S3, S4, S5 in the drawing), the intake air stream is divided and the arrow One intake air, shown as S1, directly enters the internal combustion engine (not shown), and the other intake air, shown by arrow S2, is introduced into the seal 21 via the bypass channel 20. The filtration gas side 27 of the hollow fiber membrane 30 of the first flux flows through the hollow fiber membrane 30 of the 1st speed | rate, and is connected with the intake pipe 10 which can be opened and closed by the idling setter 16. It has a gas pressure lower than the air flow which exists in the inlet of the hollow fiber membrane 30 along the inlet 23 of 21). In particular, the air flow S2 existing on the inlet side has a higher oxygen (O ₂ ) partial pressure than the filtration gas side 27. Thus, for example, German enriched upset there, and thus the intake pipe 10 of the oxygen (O ₂₎ according to Patent No. 4,404,681 filtered gas side (27) on the basis of the special properties of the film 30 such as described in No. The air flow S1 flowing therein is mixed with the air flow S3 present on the rear side of the outlet 25 of the seal 21 so that an oxygen (O ₂ ) content of greater than 21 vol% is variable, preferably 25 to An oxygen-rich air stream S4 having an oxygen content of 35 vol% is supplied to the internal combustion engine.

In this case, the blower 24 which can be started as needed supplies a sufficient airflow passing through the inside of the membrane 30 formed as a hollow fiber membrane module as described above, whereby the variable filtration gas side ( The oxygen (O ₂ ) partial pressure higher than 27) is assured.

Residual air lean in O ₂ leaves the chamber 21 from the outlet 32 as residual gas.

The idling setter is opened in the running state in which thickening of O ₂ is to be achieved. In the running state where oxygen enrichment is not necessary, the outlet of the bypass channel 20 is closed by the idling setter 16 and the blower 24 is stopped. The check valve 22 is closed, thereby preventing inversion of the flow direction in the bypass channel 20. The other check valve 34 in the outlet 32 is closed, whereby unfiltered air enters the chamber 21 to prevent intrusion into the membrane 30 by inversion of the flow direction in the outlet 32. do.

Even when the idling setter 16 is closed, if the flow in the predetermined flow direction (arrow S2) is guaranteed in the bypass channel 20 by the continuous operation of the blower 24, the check valves 24 and 34. It is obvious that there is no need for.

The embodiment shown in Fig. 2 is different from the embodiment shown in Fig. 1 described above in addition to the intake pipe 10 as well as the bypass channel 20 instead of the common air filter 14, respectively. Only different air filters 15, 17 for the engine 10 and for the bypass channel 20 are used.

In the embodiment shown in Fig. 3, the blower 24 and the idling setter 16 are not used. In this embodiment, the air flowed in while running and the suction pressure of the engine form an air flow passing through the membrane 30.

The supply of air "as a function of the driving point" is formed by the speed of the vehicle in this embodiment.

1 to 3, the inlet and outlet of the membrane 30 along the inlet 23 and the outlet 25 of the seal 21 are each in the form of parallel flow, i.e. the flow of intake air, in the membrane. It is arrange | positioned so that it may be transmitted parallel to a direction.

In the embodiment shown schematically in FIGS. 4 and 5, on the contrary, the inlet 23 and the outlet 25 of the seal 21 allow the membrane to pass through in a countercurrent shape, ie in a direction opposite to the flow direction of the intake air. It is arranged. This is shown in schematic diagram by the arrow shown as S5. By this counterflow system, the optimum oxygen O as a driving force for permeating oxygen from the air stream S2 over the entire length of the membrane 30 is obtained.₂) Partial pressure drop is guaranteed. 4 corresponds to the embodiment shown in FIG. 1 (the common air filter 14 for the intake pipe 10 and the bypass channel 20), and the embodiment shown in FIG. The form corresponds to the embodiment shown in FIG. 2 (the air filters 15 and 17 separate for the intake pipe 10 and the bypass channel 20, respectively).

By improving the method of reducing the harmful substances in the combustion exhaust gas from the internal combustion engine, the startup time of the catalyst is shortened, thereby making it possible to reduce the harmful emissions after the catalyst, particularly in the low temperature startup process.

Claims (11)

Internal combustion engines, in particular automotive internal combustion engines, in which a gas having a high oxygen (O ₂ ) content obtained from the atmosphere is supplied to the internal combustion engine by at least one membrane 30 permeable only to oxygen molecules (O ₂ ) provided in the chamber 21. In the method for reducing harmful substances in combustion exhaust gas from And the gas having a high oxygen content is incorporated into the intake air as a function of the operating point of the internal combustion engine. The internal combustion gas according to claim 1, wherein the gas having a high oxygen content is incorporated into intake air in one or a plurality of processes of a next operation state, that is, a cold start process, an idling process, a warm up process, and a partial load process. A method for reducing harmful substances in combustion exhaust gases from an engine. 3. A method according to claim 1 or 2, wherein the enrichment of oxygen (O ₂ ) is in the range of 25 to 35 vol%. In order to obtain a gas having a high oxygen (O ₂ ) content supplied to the internal combustion engine from the atmosphere, at least one membrane (30) disposed in the chamber (21) capable of supplying air and permeable only to oxygen molecules (O ₂ ) is provided. In the internal combustion engine provided, especially the harmful substance reduction apparatus in combustion exhaust gas from an automotive internal combustion engine, The chamber 21 is disposed in the bypass channel 20 arranged in parallel with the intake pipe 10 of the internal combustion engine, and the chamber 21 is in an operating state of the internal combustion engine, that is, a cold start process, an idling process, and a warm up process. And an apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine, which can be opened and closed in one or a plurality of processes of a partial load process. 5. The device of claim 4, wherein the bypass channel (20) is capable of opening and closing via an idling setter (16). The inlet 23 and the outlet 25 of the seal 21 are arranged so that the membrane 30 is permeate | transmitted in parallel flow shape in the bypass channel 20. An apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine. The inlet 23 and the outlet 25 of the seal 21 are arranged in the bypass channel 20 so that the membrane 30 is permeate | transmitted in countercurrent shape. Harmful substance reduction apparatus in combustion exhaust gas from an internal combustion engine. The combustion exhaust gas from an internal combustion engine according to any one of claims 4 to 7, wherein a common air filter (14) is provided for the intake pipe (10) and the bypass channel (20). Hazardous Substance Reduction Device. 8. The internal combustion engine according to any one of claims 4 to 7, characterized in that separate air filters (15, 17) are provided for the intake pipe (10) and the bypass channel (20), respectively. Harmful substance reduction apparatus in combustion exhaust gas. The apparatus for reducing harmful substances in combustion exhaust gas from an internal combustion engine according to any one of claims 4 to 9, wherein a bypass blower (24) capable of starting as necessary is provided in the bypass channel (20). . The hazardous substance reduction according to any one of claims 4 to 10, wherein at least one check valve (22, 34) is provided in the bypass channel (20). Device.