CN106368782A - Series HC emission active adsorption and desorption device for cold start and control strategy - Google Patents

Abstract

The invention relates to a series active adsorption and desorption device for cold start HC emission and a control strategy. Air filter device, intake pipe, engine, air filter device connected in series with engine through intake pipe; first three-way catalytic converter, exhaust pipe, adsorption device, adsorption material, second three-way catalytic converter, first three-way catalytic converter , the adsorption device, and the second three-way catalytic converter are connected in series with the engine through the exhaust pipe, and the adsorption material is placed in the adsorption device; each independent micropore on the surface of the adsorption material has two channels connected to the outside world, and the opening and closing of the channels are controlled by determined by the exhaust temperature. The device realizes the active adsorption and desorption of the HC emission at the cold start of the engine, and effectively reduces the emission at the cold start stage of the engine. The device does not require additional pipelines and valves like the parallel adsorption device; it saves space in the chassis of the car. The device solves the problem of premature desorption of pollutants due to blowing of high-temperature exhaust gas in the old serial cold start emission adsorption device.

Description

A series active adsorption and desorption device for cold start HC emission and its control strategy

technical field

The invention provides a serial cold start HC emission active adsorption and desorption device and a control strategy, which belong to the field of internal combustion engines.

Background technique

Since the three-way catalytic converter cannot reach the working temperature during the cold start of the engine, HC emissions cannot be effectively converted during the cold start of the engine, and the control unit ECU needs to increase the amount of fuel injection to ensure the smooth start of the engine. form into the atmosphere. According to relevant test results, in the NEDC cycle test, 90% of HC emissions are produced in the cold start stage of the engine. Therefore, reducing the emission of pollutant gases during engine cold start has become one of the important issues to be solved urgently for the continued development of internal combustion engines. Adsorption technology is an effective means to solve HC emissions during engine cold start due to its characteristics of low-temperature and high-pressure adsorption and high-temperature and low-pressure desorption. According to the relevant bench test results, at an ambient temperature of 20°C, more than 75% of the HC emissions during the engine cold start phase can be adsorbed in the adsorption device placed with the adsorption material.

At present, the commonly used adsorption systems can be divided into two categories: parallel adsorption system and serial adsorption system according to the installation method of the exhaust pipe. In the parallel adsorption system, the adsorption device is connected in parallel with the engine exhaust pipe. According to The different operating states of the engine determine the passage of the exhaust gas through the lines. When the engine is in the cold start stage, the control unit makes the engine exhaust gas pass through the adsorption device through the opening and closing of the valve. However, it is generally difficult for this kind of adsorption device to realize the desorption regeneration of the adsorption material. In addition, the parallel adsorption system often requires more valves to control the engine exhaust to pass through different pipelines, and compared with the conventional engine exhaust system, the parallel connection adds an extra exhaust channel, which will Occupying additional chassis space of the car is not conducive to the large-scale application of the adsorption device on the car. In the series adsorption system, the adsorption device is connected in series with the engine exhaust pipe and placed between the first and second three-way catalytic converters. When the engine is in the cold start stage, the HC emissions in the exhaust gas are adsorbed in the adsorption device, and when the second three-way catalytic converter reaches the working temperature, the HC emissions adsorbed in the adsorption device are desorbed to the second three-way catalytic converter under the action of high-temperature exhaust gas. The reaction in the two-way three-way catalytic converter, however, because the desorption temperature of HC emission is usually lower than the operating temperature of the second three-way catalytic converter, which leads to a considerable part of the HC emission being advanced before the second three-way catalytic converter reaches the operating temperature desorption, thereby greatly reducing the adsorption effect.

Therefore, it is necessary to design an adsorption system that can not only effectively reduce HC emissions during engine cold start, but also achieve desorption and regeneration of adsorption materials, avoid the problem of early desorption of adsorbed HC, simplify the structure of the adsorption system, and save the space of the car chassis. device is particularly necessary.

Contents of the invention

The purpose of the present invention is to solve the problem of high emission of automobile engine cold start, to provide a series cold start HC emission active adsorption and desorption device and control strategy, the system can not only effectively reduce the HC emission in the cold start stage of automobile engine, The active desorption regeneration of the adsorption material is realized, and the problem of early desorption of HC in the previous series adsorption system is avoided. The invention does not need additional pipelines and valve systems, saving the chassis space of the automobile.

The present invention adopts following technical scheme:

A tandem active adsorption and desorption device for HC emissions from cold start of an engine, which includes an air filter device 1, an intake pipe 2, an engine 3, a first three-way catalytic converter 4, an exhaust pipe 5, an adsorption device 6, an adsorption material 7, The second three-way catalytic converter 8, the air filter device is connected in series with the engine through the intake pipe; the first three-way catalytic converter, the adsorption device, and the second three-way catalytic converter are connected in series with the engine through the exhaust pipe, and the adsorption material is placed in the adsorption device Inside; the adsorption material has several independent microporous structures 11, and each independent micropore on the surface has two channels connected to the outside world, and the two channels connected to the outside world are I channel 9 and II channel 10.

Utilize the active adsorption and desorption device for HC emission in series cold start as described above, characterized in that:

When the exhaust gas temperature is lower than A (pollutant desorption temperature), channel I is opened and channel II is closed. At this time, the exhaust gas passes through the adsorption device 6 during the cold start of the engine, and the adsorption properties of the adsorption material 7 in the adsorption device 6 are used. Reduce HC emissions during engine cold start; when the exhaust gas temperature is not less than A and not higher than B (the light-off temperature of the second three-way catalytic converter 8), the I channel 9 is closed, and the II channel 10 is closed. At this time, it is adsorbed on the adsorption material The HC emission in the independent microporous structure 11 on 7 is stored in the independent microporous structure 11 in the adsorption material 7 due to the closing of the I channel 9 and the II channel 10; when the exhaust gas temperature is not lower than B, the I channel 9 is closed , the II channel 10 is opened, at this time, the HC emission adsorbed in the independent microporous structure 11 on the adsorption material 7 is gradually desorbed and reacted in the second three-way catalytic converter 8 under the action of the high-temperature exhaust gas due to the opening of the II channel 10 , the adsorption material 7 completes the desorption regeneration.

The opening and closing of channel 9 and channel 10 are determined by the exhaust temperature. When channel I and channel II 10 are not fully closed, the adsorption and desorption of HC emissions during the cold start of engine 3 is determined by the external exhaust temperature, that is, when the exhaust temperature is lower than the HC desorption temperature, HC is adsorbed at this time, and when the exhaust When the gas temperature is higher than the HC desorption temperature, HC is desorbed at this time; when the I channel 9 and the II channel 10 are all closed, the HC emission does not undergo adsorption and desorption during the cold start stage of the engine 3 .

An adsorption device 6 is added to the first three-way catalytic converter 4 and the second three-way catalytic converter 8, and each independent microporous structure 11 placed on the surface of the adsorption material 7 in the adsorption device 6 has and has two connections with the outside world. The opening and closing of the connected channels (I channel 9 and II channel 10) are determined by the exhaust temperature. At different exhaust temperatures, through the independent opening and closing of channel I and channel II 10, the adsorption of HC emissions during the engine cold start phase is realized; after the engine cold start phase is over and the second three-way catalytic converter 8 Storage of adsorbed HC emissions before reaching operating temperature; enabling desorption of adsorbed HC emissions after the end of the engine cold start phase and after the second three-way catalytic converter 8 has reached operating temperature.

Under the premise of realizing the active adsorption and desorption of HC emissions by the adsorption material to the engine cold start stage, the device avoids the problem of early desorption of the adsorbed HC emissions, thereby improving the adsorption effect of the adsorption device; in addition, the device has no additional The pipeline and valve system save space; no additional control unit is needed, which greatly simplifies the complexity of the system.

Description of drawings

Fig. 1 structure and working principle diagram of the present invention

In the figure: 1. Air filter device, 2. Intake pipe, 3. Engine, 4. First three-way catalytic converter, 5. Exhaust pipe, 6. Adsorption device, 7. Adsorption material, 8. Second three-way catalytic converter

Fig. 2 is the schematic diagram of independent microporous structure channel of the present invention

In the figure: 7. Adsorption material, 9. Channel I, 10. Channel II, 11. Independent microporous structure

detailed description

Below in conjunction with accompanying drawing and specific embodiment the present invention will be further described:

The present invention comprises: air filter device 1, intake pipe 2, engine 3, air filter device 1 is connected in series with engine 3 through intake pipe 2; first three-way catalytic converter 4, exhaust pipe 5, adsorption device 6, adsorption material 7 , the second three-way catalytic converter 8, the first three-way catalytic converter 4, the adsorption device 6, and the second three-way catalytic converter 8 are connected in series with the engine 3 through the exhaust pipe 5, and the adsorption material 7 is placed in the adsorption device 6; Each independent microporous structure 11 on the surface of the adsorption material 7 has and has two channels (I channel 9 and II channel 10) connected to the outside world, and the opening and closing of the channels are determined by the exhaust temperature.

The channel material may be composed of a phase-change material, and when a phase change occurs, the channel is opened or closed due to a change in shape or volume of the material. For example, it is set that when the material of the channel is in liquid state, the channel is in the open state, otherwise, the channel is in the closed state; the phase transition temperature of the material in channel Ⅰ is A, and the phase transition temperature of the material in channel Ⅱ is B. When the exhaust temperature is lower than A When the material of channel I is liquid, the material of channel II is solid, and the channel state is open; when the exhaust temperature is between A and B, the material of channel I is solid, the material of channel II is solid, and the channel state is Closed; when the exhaust temperature is not less than B, the material of channel Ⅰ 9 is solid, the material of channel Ⅱ 10 is liquid, and the channel state is open.

When the engine 3 starts, that is, the engine 3 is in the cold start stage, the air passes through the air filter device 1 and enters the engine 3 for combustion through the intake pipe 2, and the exhaust gas produced by the engine 3 enters the adsorption device 6 through the exhaust pipe 5. Since the exhaust gas temperature is lower than A (for example, the HC desorption temperature is 120°C), the I channel 9 on each independent microporous structure 11 of the adsorption material 7 is opened, and the II channel 10 is closed, and the HC discharge is adsorbed on the adsorption material 7 through the I channel 9 Among the microporous structures 11 above.

When the cold start phase of the engine 3 ends, with the gradual increase of the exhaust temperature, when the exhaust temperature is not less than A, the I channel 9 on each independent microporous structure 11 of the adsorption material 7 is closed, and the II channel 10 is closed. The HC emission in the microporous structure 11 adsorbed on the adsorption material 7 does not desorb due to the closure of the I channel 9 and the II channel 10 .

As the exhaust temperature continues to rise, when the exhaust temperature is not less than B (for example, the operating temperature of the second three-way catalytic converter 8 is 350 ° C), the I channel 9 on each independent microporous structure 11 of the adsorption material 7 is closed, The II channel 10 is opened, and at this time, the HC emission adsorbed in the microporous structure 11 on the adsorption material 7 is desorbed due to the opening of the II channel 10, and enters the second three-way catalytic converter 8 through the exhaust pipe 5 to react, The adsorption material 7 has been regenerated.

When the engine 3 stops running, because the exhaust gas temperature gradually drops until it is not higher than A, at this time, the I channel 9 on each independent microporous structure 11 of the adsorption material 7 is opened, and the II channel 10 is closed. Due to the opening of the I channel, the HC emission of the engine 3 at the next cold start stage can be adsorbed in the independent microporous structure 11 on the adsorption material 7 via the I channel.

Fig. 2 is a schematic diagram of channels in the independent microporous structure of the adsorption material, which is only an example of the adsorption material involved in the present invention, and is not intended to limit the adsorption material involved in the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (2)

1. a kind of tandem engine cold start hc discharges active adsorption/desorption device, and it includes air filter (1), air inlet Pipe (2), electromotor (3), the first ternary catalyzing unit (4), exhaustor (5), adsorbent equipment (6), adsorbing material (7), the second ternary Catalyst converter (8), air filter is connected in series with electromotor by air inlet pipe；First ternary catalyzing unit, adsorbent equipment, second Ternary catalyzing unit is connected in series with electromotor by exhaustor, and adsorbing material is positioned in adsorbent equipment；On described adsorbing material There are some independent microcellular structures (11), each independent wells on surface have 2 passages being connected with the external world, and two with outward The passage that boundary is connected is passage (9) and passage (10).

2. apply device as claimed in claim 1 control strategy it is characterised in that:

When delivery temperature is less than pollutant desorption temperature a, passage (9) is opened, and passage (10) is closed, and now electromotor is cold Adsorbent equipment is passed through in start-up period aerofluxuss, and the characterization of adsorption using adsorbing material in adsorbent equipment reduces the engine cold starting stage Hc discharges；When delivery temperature is not less than pollutant desorption temperature a and the not higher than second ternary catalyzing unit initiation temperature b, passage Close, pathway closure, be now adsorbed in hc discharge in independent wells structure on adsorbing material due to passage and passage Close and be stored in the microcellular structure in adsorbing material；When delivery temperature is higher than b, pathway closure, passage is opened, this When be adsorbed in hc in independent wells structure on adsorbing material and discharge due to the unlatching of passage, in the presence of high-temperature tail gas by Gradually solution is attached in the second ternary catalyzing unit and reacts away, and adsorbing material completes desorption and regeneration.