Method and apparatus for enriching the oxygen content in the intake air of an internal combustion engine

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METHOD AND APPARATUS FOR inducted air of an internal combustion engine in Such a ENRICHING THE OXYGEN CONTENT IN manner that a reduction of the toxic emissions of the engine THE INTAKE AIR OF AN INTERNAL is made possible while, on the other hand, an increase of the COMBUSTION ENGINE power of the engine is made possible at the same time. The method of the invention is for enriching the oxygen

FIELD OF THE INVENTION content in the intake air of an internal combustion engine The invention relates to a method for enriching the having providing an intake channel. The method includes the Steps of:

an enrichment channel opening into the intake oxygen content in the intake air of an internal combustion channel; passing engine. The enrichment of the oxygen content takes place in and conducting ambient air into the enrichment channel the ambient air through a membrane that air is guided through a membrane permeable only for oxygen molecules. This membrane is mounted in an enrich mounted in the enrichment channel to obtain oxygen ment channel opening into the intake channel. The oxygen enriched air, the membrane being permeable primarily for content in the intake channel is continuously detected by at oxygen molecules, continuously detecting the oxygen con least one Sensor device. tent in the intake channel utilizing Sensor means, and, 15 utilizing drivable actuator means to change the concentra

BACKGROUND OF THE INVENTION tion of the inducted air and the oxygen enriched air in A method and an arrangement for reducing the toxic dependence CS.

upon the oxygen content detected by the Sensor

Substances in combustion exhaust gases wherein a gas In the arrangement of the invention, the change of the having an increased oxygen content is Supplied to the concentrations for the inducted air as well as for the oxygen inducted air is disclosed, for example, in U.S. patent appli cation Ser. No. 08/682.593, filed Feb. 2, 1996, and incor enriched air is achieved by at least one controllable actuator porated herein by reference. The oxygen-enriched gas is in the dependence upon the detected oxygen content. This has especially Significant advantage that a continuous control obtained in that air is guided through a membrane which is of the oxygen content of the intake air Supplied to the engine permeable only for oxygen molecules and is mounted in a is possible So that the engine can always be operated in an chamber 25 operating State which, on the one hand, makes possible a With this kind of an oxygen enrichment of the air supplied reduction of the emission of toxic Substances and, on the to the engine, the exhaust-gas temperature is increased and other hand, makes possible an optimal yield with respect to therefore the Start time of the catalytic converter is reduced. power.

This start time is that time which elapses before the catalytic converter reaches its operating temperature and its full With the controlled increase of the oxygen content of the operational effect. At the same time, the fuel conversion in intake air, a reduction of the carbon monoxide and hydro the engine is improved So that the raw emissions of carbon carbon emissions is possible in the manner described above and the power density is increased So that the oxygen is monoxide and hydrocarbons (CO, HC) are reduced. Supplied to the combustion operation. More fuel can be Furthermore, the nitrogen content during combustion is reduced whereby less nitrogen oxide is produced which injected because of the increased oxygen content for a must be catalytically converted to reduce the burden to the 35 limited Swept Volume which is present for each engine. In this way, the power yield is increased. It is also especially environment.

In a method and an arrangement of this kind, it is advantageous that the oxygen can be obtained on board the problematical that the oxygen content of the oxygen vehicle channel.

Via the membrane which is enriched in the enriching enriched gas (which is Supplied to the intake air) cannot be exactly determined So that, for example, an exact control of 40 In principle, different Sensor devices can be utilized to the combustion processes is not possible by means of an detect the oxygen content. In an advantageous embodiment, engine control known per se. Rather, the control must take which the oxygen content is detected by at least one oxygen probe place indirectly, that is, by known Sensor means and engine is mounted rearward of the at least one actuator. In controls which, however, requires a considerable interven engine canthebeoxygen this way, content of the intake air Supplied to the detected in an especially simple manner.

tion into the control algorithms of the engine control. 45

An arrangement for controlling an exhaust-gas feedback In addition, a pressure Sensor can be provided especially is disclosed in U.S. Pat. No. 4,905,564. In this arrangement, with by respect to a correction of the oxygen content detected the oxygen probe. With this preSSure Sensor, the preSSure the control of the fed-back exhaust gas is made possible via is detected in the intake channel rearward of the actuator. an exhaust-gas feedback valve. In this arrangement, an oxygen probe is provided which detects the oxygen content 50 The invention is also directed to an arrangement for in the intake channel. An internal combustion engine is enriching the oxygen content in the intake air of an internal controlled in dependence upon the detected Sensor Signal. combustion engine. This arrangement includes an enrich An arrangement of this kind does not make possible the ment channel, which can be Subjected to ambient air and control of the oxygen content. Furthermore, the arrangement which opens into the intake channel of the engine. At least does not make possible an oxygen enrichment because the 55 one membrane is mounted in the enrichment channel and at fed-back exhaust gas contains less oxygen than the usual least one Sensor device is provided in the intake channel to inducted air. Such an exhaust-gas feedback Serves essen detect the oxygen content. The membrane is permeable only tially to reduce the nitrogen oxide (NO) as known per Se for oxygen molecules.

which is effected in that the fed-back exhaust gas (that is, an With respect to the above, it is an object of the invention inert gas) is admixed to the inducted air. In this way, the 60 to provide an arrangement for enriching the oxygen content combustion temperature is reduced and less nitrogen oxide in the intake air of an internal combustion engine which is generated. A reduction of the toxic emission while Simul makes possible a controlled oxygen enrichment of the intake taneously increasing the power of the engine is not possible air in a simple manner.

with an arrangement of this kind. The arrangement of the invention is for enriching the SUMMARY OF THE INVENTION oxygen content of the intake air of an internal combustion 65 engine having an intake channel. The arrangement includes:

In view of the above, it is an object of the invention to an enrichment channel for receiving ambient air and opening provide a method for enriching the oxygen content in the into the intake channel; a membrane permeable primarily for

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oxygen molecules and being mounted in the enrichment oxygen at the output end, that is, in the enrichment channel channel to obtain oxygen-enriched air for admixing with the 30. A blower or a compressor (not shown) can be provided intake air; Sensor means for detecting the oxygen content in forward of the membrane 32 in the enrichment channel 30 the intake channel; actuator means for metering the oxygen to increase the efficiency. The blower or compressor enriched air, and, control means for controlling the actuator eXchanges the air, which is enriched by oxygen, forward of means to meter the oxygen-enriched air in dependence upon the membrane 32.

the oxygen content detected by the Sensor means. An oxygen probe 50 as well as a pressure Sensor 52 are The metering of oxygen-enriched air via the controlled provided in the intake channel 20 downstream of the open drivable actuator in dependence upon the oxygen content, ing of the enrichment channel 30. With the oxygen probe 50, which is detected by the Sensor device, has the especially the oxygen content in the intake channel 20 is detected and, Significant advantage that a precise control of the Supply of with the pressure Sensor 52, the pressure present in the oxygen-enriched air is possible with relatively little techni intake channel 20 is detected. The detected oxygen content cal complexity. and preSSure are transmitted to the control apparatus 40. With respect to the sensor device, the most different kind The control apparatus 40 can, for example, be an engine of Sensor device can, in principle, be considered. 15 control known per Se. In the control apparatuS 40, the Advantageously, the Sensor device can however be an oxy oxygen content of the intake air to be Supplied to the engine gen probe which is mounted rearward of the actuator. This 10 is determined from the above detected oxygen and oxygen probe makes possible a precise determination of the preSSure and is precisely adjusted by driving the throttle oxygen content of the inducted air. flaps 24 and 34. With this oxygen increase, the toxic Furthermore, the above-mentioned Sensor device can Substance emissions are reduced and an increase of the include an additional pressure Sensor mounted rearward of power of the engine 10 is made possible.

the actuator. In this way, especially the partial pressure of the It is understood that the foregoing description is that of the oxygen present in the intake air can be determined. A preferred embodiments of the invention and that various preSSure Sensor of this kind can Simultaneously be used to changes and modifications may be made thereto without determine the load signal of the engine. 25 departing from the Spirit and Scope of the invention as

The most different embodiments are conceivable with defined in the appended claims.

respect to the configuration of the actuator. In one What is claimed is:

embodiment, the actuator is a flap closing the opening of the 1. A method for enriching the oxygen content in the intake enrichment channel. air of an internal combustion engine having an intake In an especially advantageous embodiment, a separate channel, the method comprising the Steps of:

metering of the oxygen-enriched air as well as the intake air providing an enrichment channel opening into Said intake is possible and, in this embodiment, the actuator includes a channel;

throttle flap mounted in the intake channel and a throttle flap passing ambient air into Said enrichment channel and mounted in the enrichment channel. conducting said ambient air through a membrane The Sensor device and the actuator are electrically con 35 mounted in Said enrichment channel to obtain oxygen nected to a control apparatus. The control apparatus can, for enriched air, Said membrane being permeable primarily example, be part of an engine control of the internal com for oxygen molecules, bustion engine which is anyway present. continuously detecting the oxygen content in Said intake BRIEF DESCRIPTION OF THE DRAWING channel utilizing Sensor means, and, The invention will now be described with reference to the 40 utilizing drivable actuator means to change the concen tration of Said inducted air and Said oxygen enriched air single FIGURE (FIG. 1) of the drawing which shows a in dependence upon the oxygen content detected by Schematic of the arrangement according to the invention for Said Sensor means.

enriching the oxygen content in the intake air of an internal 2. The method of claim 1, comprising the further step of combustion engine. 45 providing an oxygen probe as part of Said Sensor means and DESCRIPTION OF THE PREFERRED placing Said oxygen probe downstream of Said actuator EMBODIMENTS OF THE INVENTION means for detecting Said oxygen content.

3. The method of claim 2, comprising the further step of

The method for enriching the oxygen content in the intake providing a pressure Sensor as part of Said Sensor means and air of an internal combustion engine is best explained in placing Said pressure Sensor downstream of Said actuator connection with an arrangement for carrying out the method 50 means to detect the pressure present in Said intake channel. of the invention. An arrangement for enriching the oxygen 4. An arrangement for enriching the oxygen content of the content in the intake air of an internal combustion engine 10 intake air of an internal combustion engine having an intake includes an intake channel 20 and an enrichment channel30. channel, the arrangement comprising: The intake channel 20 is closed at the input end thereof by 55 an enrichment channel for receiving ambient air and an air filter 22 known per se. This filter prevents dust opening into Said intake channel; particles and the like from reaching the engine 10. In the a membrane permeable primarily for oxygen molecules intake channel 20, a throttle flap 24 is mounted which can be and being mounted in Said enrichment channel to driven by a control apparatus 40. With the throttle flap 24, obtain oxygen-enriched air for admixing with Said the intake channel 20 can be entirely or partially closed. intake air;

The enrichment channel 30 opens into the intake channel Sensor means for detecting the oxygen content in Said 20. Here too, a throttle flap 34 is provided which can be intake channel;

driven by control apparatus 40. With the throttle flap 34, the enrichment channel 30 can be entirely or partially closed. actuator means for metering Said oxygen-enriched air; A membrane 32 is mounted in the enrichment channel 30 and, and is permeable especially for oxygen molecules. Air is 65 control means for controlling Said actuator means to meter drawn through this membrane 32 by the underpressure Said oxygen-enriched air in dependence upon Said present in the intake channel. This air is enriched with Oxygen content detected by Said Sensor means.

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S 6 5. The arrangement of claim 4, Said Sensor means and Said 8. The arrangement of claim 4, Said actuator means actuator means being electrically connected to Said control including a throttle flap for opening and closing Said enrich CS. ment channel.

6. The arrangement of claim 5, Said Sensor means includ 9. The arrangement of claim 4, Said actuator means ing an oxygen probe mounted downstream of Said actuator

CS. including a first throttle flap mounted in Said intake pipe and 7. The arrangement of claim 6, Said Sensor means further a Second throttle flap mounted in Said enrichment channel. including a pressure Sensor mounted downstream of Said actuatOr means.