阅读说明：本技术 一种带双氧化型催化转化器的后处理系统 (Aftertreatment system with dual-oxidation catalytic converter ) 是由 王春玲 蒙小聪 陶泽民 樊心龙 孙朝进 仇海龙 陈晓克 姜刚 韦林茵 于 2020-04-14 设计创作，主要内容包括：本发明涉及柴油机尾气后处理技术领域,具体是一种带双氧化型催化转化器的后处理系统,包括沿排气方向依次设置于发动机的排气管道上的高压EGR系统、增压器、前置氧化型催化转化器、选择性催化还原器、后置氧化型催化转化器和颗粒物捕集器。采用高压EGR+双DOC-SCR-CDPF排放路线,不需要布置低压EGR和高低压EGR系统中所需的水空中冷系统,使发动机布置难度下降,解决小排量发动机的配套适应性,同时可降低成本。(The invention relates to the technical field of diesel engine tail gas aftertreatment, in particular to an aftertreatment system with a dual-oxidation type catalytic converter. The high-pressure EGR and double DOC-SCR-CDPF discharging route is adopted, a water-air cooling system required in a low-pressure EGR system and a high-pressure and low-pressure EGR system is not required to be arranged, the arrangement difficulty of the engine is reduced, the matching adaptability of a small-displacement engine is solved, and the cost can be reduced.)

1. An after-treatment system with a dual oxidation type catalytic converter is characterized in that: the device comprises a high-pressure EGR system (2), a supercharger (3), a front-mounted oxidation type catalytic converter (4), a selective catalytic reducer (5), a rear-mounted oxidation type catalytic converter (6) and a particulate matter trap (7) which are sequentially arranged on an exhaust pipeline (1) of an engine along the exhaust direction, wherein the front-mounted oxidation type catalytic converter (4) and the selective catalytic reducer (5) are packaged into an integral structure and are tightly coupled and connected to the rear end of the supercharger (3).

2. The aftertreatment system with a dual oxidation-type catalytic converter of claim 1, wherein: the high-pressure EGR system (2) comprises an EGR valve and an EGR cooler which are arranged between a communication pipeline of an air inlet pipeline (10) and an exhaust pipeline (1) of the engine and integrated into a whole, and the EGR valve and the EGR cooler are installed on the air inlet side.

3. The aftertreatment system with a catalytic converter of the double oxidation type according to claim 1 or 2, characterized in that: the particulate matter trap (7) is a catalytic particulate trap.

4. The aftertreatment system with a catalytic converter of the double oxidation type according to claim 1 or 2, characterized in that: an HC injection device (8) is provided in the exhaust gas line (1) between the pre-oxidation catalytic converter (4) and the post-oxidation catalytic converter (6).

5. The aftertreatment system with a catalytic converter of the double oxidation type according to claim 1 or 2, characterized in that: the post-oxidation catalytic converter (6) and the particulate matter catcher (7) are packaged into an integral structure.

Technical Field

The invention relates to the technical field of diesel engine tail gas aftertreatment, in particular to an aftertreatment system with a dual-oxidation catalytic converter.

Background

The national six diesel engine is discharged by a passenger car, Euro 7 and national six b discharge are achieved by generally adopting a discharge route of high-pressure EGR + low-pressure EGR + DOC + SCRF + SCR + ASC, the high-pressure EGR and the low-pressure EGR are respectively arranged at the front and the back of a water air cooler, the large EGR rate is realized to reduce the NOx discharge, the DOC + SCRF is installed on an engine in a close coupling mode after a supercharger vortex by adopting a U-shaped package or a linear package, and the secondary post-processing SCR + ASC is arranged on a whole car.

Disclosure of Invention

The invention provides a post-treatment system with a dual-oxidation catalytic converter, which adopts a high-pressure EGR + dual DOC-SCR-CDPF discharge route, does not need to arrange a water-air cooling system required in a low-pressure EGR system and a high-pressure and low-pressure EGR system, reduces the difficulty of engine arrangement, solves the matching adaptability of a small-displacement engine, and simultaneously can reduce the cost.

In the invention, SCR is a selective catalytic reducer, DOC is an oxidation type catalytic converter, DPF is a particulate matter trap, EGR is an exhaust gas recirculation system, and CDPF is a catalytic type particulate matter trap.

The technical scheme of the invention is as follows: the utility model provides a take dual oxidation type catalytic converter's aftertreatment system, includes along the exhaust direction sets gradually high-pressure EGR system, booster, leading oxidation type catalytic converter, selective catalytic reduction ware, rearmounted oxidation type catalytic converter and particulate matter trap on the exhaust duct of engine, leading oxidation type catalytic converter with selective catalytic reduction ware encapsulates into an organic whole structure and close coupling and connects at the booster rear end, rearmounted oxidation type catalytic converter with particulate matter trap equipartition is put on the frame of whole car.

The invention adopts high-pressure EGR and double DOC-SCR-DPF, the double DOC post-treatment arrangement is divided into a two-stage independent structure of a front oxidation type catalytic converter and a rear oxidation type catalytic converter, the exhaust temperature of the oxidation catalyst of the front oxidation type catalytic converter is high, the efficiency in converting CO and HC in exhaust is high, and NO in the exhaust can be oxidized into NO₂The low-temperature conversion efficiency of SCR is improved, the exhaust turbulence of the engine body is utilized to mix the urea aqueous solution, the design of the mixer is simplified, the total volume is reduced, the adaptability is strong, and the cost is reduced. NO converted by a simultaneous post-oxidation catalytic converter₂Can be used for passive regeneration to avoid DPF blockage, has good emission margin of the whole device, and ensures that the engine can be used in passenger vehicle emissionStably reaches the discharge standard of the nation 6 b.

In addition, the invention does not need to arrange a water-air cooling system required by a low-pressure EGR system and a high-pressure and low-pressure EGR system, thereby reducing the difficulty of the arrangement of the engine, solving the matching adaptability of the small-displacement engine and reducing the cost.

Preferably, the high pressure EGR system includes an EGR valve and an EGR cooler that are provided between an intake pipe and an exhaust pipe communication pipe of the engine and are integrated, the EGR valve and the EGR cooler being installed on an intake side. The EGR valve and the EGR cooler are integrated into a modular design, are arranged on the air inlet side, and are used for introducing air from a cylinder cover exhaust gas channel, returning to the air inlet connecting pipe through the EGR valve and the EGR cooler and circulating to an engine air inlet system, so that the structure is compact, and the whole vehicle can be conveniently adapted.

Preferably, the particulate matter trap is a catalytic particulate matter trap, namely a CDPF unit, and the CDPF unit has low back pressure and lower oil consumption compared with the SCRF unit.

Preferably, an HC injection device is provided in an exhaust pipe between the front oxidation catalytic converter and the rear oxidation catalytic converter. And the risk of dilution of engine oil in the cylinder is eliminated by using an HC injection device in front of the rear oxidation type catalytic converter, so that the reliability of the engine is improved.

Preferably, the rear-mounted oxidation type catalytic converter and the particulate matter catcher are packaged into an integral structure, the structure is more compact, the whole vehicle is convenient to adapt, and the matching adaptability is high.

The invention has the beneficial effects that:

1. the arrangement of the low-pressure EGR and the water-air intercooler is reduced, so that the arrangement is simpler and the cost is reduced.

2. By adopting a double DOC + SCR + CDPF post-treatment arrangement structure, the matching compactness is improved, the oil consumption is reduced, and the national emission standard of the passenger car is achieved by using a scheme with lower cost.

3. And an HC nozzle is used between two DOCs to eliminate engine oil dilution, so that the reliability of the engine is improved.

Drawings

FIG. 1 is a block diagram of an aftertreatment system with a dual oxidation catalytic converter in accordance with the present invention.

In the figure: 1-an exhaust pipeline, 2-a high-pressure EGR system, 3-a supercharger, 4-a front-mounted oxidation type catalytic converter, 5-a selective catalytic reducer, 6-a rear-mounted oxidation type catalytic converter, 7-a particulate matter trap, 8-an HC injection device, 9-a urea injection system and 10-an air inlet pipeline.

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.