CN113356989A - Automatically-adjustable heat preservation device for diesel engine exhaust system - Google Patents

Abstract

The invention relates to an automatically adjustable thermal insulation device for a diesel engine exhaust system. A protective casing is fixedly sleeved and installed on the outside of an exhaust gas aftertreatment system; Layer connection; the inflation and deflation pump is connected with the airbag for inflating and deflating the airbag. Compared with the prior art, the present invention is provided with an automatically adjustable thermal insulation device outside the exhaust gas after-treatment system, the position of the protective shell is fixed, the airbag is respectively connected with the protective shell and the thermal insulation layer, and when the exhaust temperature is low, the airbag is inflated. Drive the thermal insulation layer close to the side wall of the exhaust after-treatment system, which plays a role of thermal insulation and ensures that the catalytic reaction in the exhaust after-treatment system can proceed normally. The side wall plays a cooling role to avoid damage to the exhaust gas after-treatment system and thermal insulation layer due to excessive temperature.

Description

Automatically-adjustable heat preservation device for diesel engine exhaust system

Technical Field

The invention relates to the technical field of engine parts, in particular to an automatically-adjustable heat preservation device for an exhaust system of a diesel engine.

Background

In order to meet the national emission standards of five and six countries implemented by motor vehicles in China at present, the exhaust gas needs to be subjected to post-treatment, and in an exhaust gas post-treatment system, in order to reach the catalytic temperature of the urea chemical reaction, the temperature of the exhaust gas entering the SCR box of the selective catalytic reduction device must reach a certain temperature requirement. On the other hand, when the temperature in the exhaust pipe and the exhaust gas aftertreatment system is too high, heat energy is radiated to the surroundings, so that the parts such as hoses and wire harnesses are accelerated to age, and the service lives of the parts are shortened. Therefore, it is necessary to wrap the outer surfaces of the exhaust pipe and the exhaust gas aftertreatment system with heat insulating materials to ensure the temperature of the exhaust gas entering the exhaust gas aftertreatment system, the temperature inside the exhaust gas aftertreatment system, and the service life of the surrounding components.

In the prior art, in order to enable an exhaust pipe to have a good heat preservation effect, chinese patent CN209925073U discloses a heat preservation structure of the exhaust pipe, which can effectively improve the protection performance and the heat insulation performance to the outside of the exhaust pipe by wrapping a volcanic knitted heat preservation layer, a protection pipe and a heat preservation and heat insulation casing outside the exhaust pipe; in order to make the exhaust gas post-treatment system have a good heat preservation effect, chinese patent CN109339927A discloses a cylindrical exhaust gas post-treatment packaging external heat preservation and insulation structure, which can not only preserve heat for post-treatment, but also play a role in heat insulation and protection for peripheral parts of an engine, and perform full-cylinder heat preservation for post-treatment, and has a good heat preservation effect.

However, the temperature of the exhaust gas is different due to different engine operating conditions. The exhaust temperature is lower in the idling cold start process, so that the heat-insulating structure arranged outside the exhaust pipe and the tail gas after-treatment system can store heat energy, and the temperature of the tail gas entering the selective catalytic reduction device SCR can reach the temperature of catalytic chemical reaction. However, in the high-speed and high-load stage of the engine, the exhaust temperature rises rapidly, the exhaust overheating can affect the exhaust aftertreatment system, especially for a particulate filter (DPF) in the exhaust aftertreatment system, the excessive temperature can cause the local heating of the DPF to be uneven, so that the DPF is inactivated, and in a serious case, even the filter body cracks. Moreover, excessive exhaust temperatures may affect the thermal insulation structures outside the exhaust pipe and the exhaust aftertreatment system, reducing their useful life.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide an automatically-adjustable heat preservation device for an exhaust system of a diesel engine, the automatically-adjustable heat preservation device is arranged outside the exhaust aftertreatment system and sequentially comprises a protective shell, an air bag and a heat preservation layer from outside to inside, the outer side of the air bag is connected with the protective shell, the inner side of the air bag is connected with the heat preservation layer, the position of the protective shell is fixed, when the exhaust temperature is low, the air bag is inflated to drive the heat preservation layer to be close to the side wall of the exhaust aftertreatment system, so that the heat preservation effect is achieved, the catalytic reaction in the exhaust aftertreatment system can be ensured to be normally carried out, when the exhaust temperature is high, the air bag is deflated to drive the heat preservation layer to be far away from the side wall of the exhaust aftertreatment system, so that the cooling effect is achieved, and the exhaust aftertreatment system and the heat preservation layer can be prevented from being damaged due to overhigh temperature.

The purpose of the invention can be realized by the following technical scheme:

an automatically adjustable heat preservation device for a diesel engine exhaust system, wherein the diesel engine exhaust system comprises an engine and a tail gas post-treatment system, the front end of the tail gas post-treatment system is connected with the engine through an exhaust pipe, and the rear end of the tail gas post-treatment system is connected with a tail pipe; an automatically adjustable heat preservation device is arranged outside the tail gas aftertreatment system, and comprises a protective shell, an air bag, a heat preservation layer and an air charging and discharging pump;

the protective shell is fixedly sleeved outside the tail gas aftertreatment system;

the air bag and the heat-insulating layer are coated outside the side wall of the tail gas aftertreatment system, the outer side of the air bag is connected with the inner side wall of the protective shell, and the inner side of the air bag is connected with the heat-insulating layer;

the air inflation and deflation pump is connected with the air bag and is used for inflating and deflating the air bag, the air bag is inflated and expanded to drive the heat insulation layer to be in contact with the side wall of the tail gas post-treatment system, and the air bag is deflated and contracted to drive the heat insulation layer to be far away from the side wall of the tail gas post-treatment system, so that a cavity is formed between the heat insulation layer and the side wall of the tail gas post-treatment system;

the protective shell is provided with a through hole communicated with the cavity, and air can flow in the cavity between the side wall of the tail gas aftertreatment system and the heat insulation layer along the through hole to take away heat.

Preferably, the exhaust gas aftertreatment system comprises an oxidation catalyst DOC, a particulate trap DPF and a selective catalytic reduction device SCR.

Preferably, the automatically-adjustable heat preservation device further comprises a controller and a temperature sensor, the controller is in communication connection with the temperature sensor and the air charging and discharging pump, the temperature sensor is installed inside the tail gas post-treatment system and used for measuring the internal temperature of the tail gas post-treatment system, and the controller controls the air charging and discharging pump based on the temperature measured by the temperature sensor and a preset temperature range; when the temperature is lower, aerify in to the gasbag by inflating and deflating pump, the inflation extrusion heat preservation of gasbag is close to tail gas aftertreatment system's lateral wall, play good heat preservation effect, when the temperature is higher, by inflating and deflating pump to the gasbag internal gas release, the lateral wall that tail gas aftertreatment system was kept away from to the gasbag shrink drive heat preservation, vacuole formation between heat preservation and the lateral wall of tail gas aftertreatment system, through-hole and cavity intercommunication on the protective housing to take away the heat by the air of circulation, play the cooling effect.

Preferably, the number of the air bags is multiple, the axial direction of the exhaust gas after-treatment system is taken as the length direction, the length of the air bags is matched with the length of the exhaust gas after-treatment system, and the air bags are uniformly distributed in the circumferential direction of the exhaust gas after-treatment system.

Preferably, the number of the air bags is 8, and the air bags are uniformly distributed in a ring shape along the circumferential direction of the exhaust aftertreatment system.

Preferably, through connecting the trachea intercommunication between the adjacent gasbag, one side of gasbag is provided with the gas port, and the inflation and deflation pipe is placed to the inside of gas port, and the inflation and deflation pump passes through inflation and deflation pipe and is connected with a gasbag, fills the gassing to this gasbag, because through connecting the trachea intercommunication between the gasbag, all the other gasbags also can fill the gassing in proper order.

Preferably, the protective shell comprises a first end face connected with the exhaust pipe and a second end face connected with the tail pipe, and the through holes are formed in the first end face and the second end face.

Preferably, the through hole is an annular hole, the annular hole arranged on the first end face is concentric with the first end face, and the annular hole arranged on the second end face is concentric with the second end face.

Preferably, the through hole comprises a plurality of openings, the plurality of openings are annularly distributed on the first end face, and the plurality of openings are annularly distributed on the second end face.

Preferably, the air bag is a double-layer air bag, the inner layer is made of a silicon rubber material, and the outer layer is formed by compounding oxford fabric and polyester fibers.

Preferably, the material of heat preservation is basalt fiber material, and the principal ingredients is that silica fiber weaves, and high temperature resistant and thickness are thin, through the fixed bonding of hot melt adhesive between gasbag and the heat preservation, can guarantee the stability of being connected between heat preservation and the gasbag.

Preferably, the outer parts of the exhaust pipe and the tail pipe are provided with heat insulation layers or automatic adjustable heat insulation devices, and each automatic adjustable heat insulation device comprises a protective shell, an air bag, a heat insulation layer and an inflation and deflation pump;

the protective shell is fixedly sleeved outside the exhaust pipe and the tail pipe;

the air bag and the heat-insulating layer are coated outside the outer walls of the exhaust pipe and the tail pipe, the outer side of the air bag is connected with the inner side wall of the protective shell, and the inner side of the air bag is connected with the heat-insulating layer;

the inflation and deflation pump is connected with the air bag and used for inflating and deflating the air bag, the air bag is inflated and expanded to drive the heat insulation layer to contact the outer walls of the exhaust pipe and the tail pipe, and the air bag is deflated and contracted to drive the heat insulation layer to be far away from the outer walls of the exhaust pipe and the tail pipe, so that a cavity is formed between the heat insulation layer and the outer walls of the exhaust pipe and the tail pipe;

the protective shell is provided with a through hole communicated with the cavity, and air can flow in the cavity between the outer walls of the exhaust pipe and the tail pipe and the heat insulation layer along the through hole to take away heat.

Compared with the prior art, the invention has the following beneficial effects:

(1) but set up automatically regulated heat preservation device outside tail gas aftertreatment system, from the extroversion inwards be protective housing in proper order, gasbag and heat preservation, the outside and the protective housing of gasbag are connected, the inboard and the heat preservation of gasbag are connected, protective housing's rigidity, when exhaust temperature is lower, the gasbag is aerifyd and is driven the lateral wall that the heat preservation is close to tail gas aftertreatment system, thereby play the heat preservation effect, catalytic reaction in the assurance tail gas aftertreatment system can normally go on, when exhaust temperature is higher, the gasbag is deflated and is driven the lateral wall that tail gas aftertreatment system was kept away from to the heat preservation, thereby play the cooling effect, can avoid damaging tail gas aftertreatment system and heat preservation because of the high temperature.

(2) Set up a plurality of gasbags, through connecting the trachea intercommunication between the adjacent gasbag, fill the air pump and be connected with a gasbag through filling the trachea, the gasbag of being connected with the heat preservation layer when aerifing like this can aerify one by one, avoids the heat preservation layer to produce great fold, and the heat preservation effect is better.

(3) The protective shell is provided with through holes communicated with the cavity, and air can flow in the cavity through the through holes in the two end faces of the protective shell, so that heat is taken away, and a cooling effect is achieved.

Drawings

FIG. 1 is a schematic structural view of an automatically adjustable thermal insulation device after an air bag is inflated in the embodiment;

FIG. 2 is a schematic structural view of an automatically adjustable thermal insulation device after deflation and contraction of an air bag in the embodiment;

FIG. 3 is a cross-sectional view taken along line A-A of FIG. 1;

FIG. 4 is a schematic view of a via;

FIG. 5 is a schematic view of a via;

FIG. 6 is a schematic view of the structure of the bladder;

reference numerals: 1. the device comprises an engine, 2, an exhaust gas post-treatment system, 3, an exhaust pipe, 4, a tail pipe, 5, a protective shell, 501, a through hole, 6, an air bag, 7, a heat insulation layer, 8, an inflation and deflation pipe, 9, an inflation and deflation pump, 10, a connecting air pipe, 11 and a cavity.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

In the drawings, structurally identical elements are represented by like reference numerals, and structurally or functionally similar elements are represented by like reference numerals throughout the several views. The size and thickness of each component shown in the drawings are arbitrarily illustrated, and the present invention is not limited to the size and thickness of each component. Parts are exaggerated in the drawing where appropriate for clarity of illustration.

In the description of the embodiments of the present application, it is to be understood that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like, refer to the orientation or positional relationship as shown in the drawings, or as conventionally placed in use of the product of the application, or as conventionally understood by those skilled in the art, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be operated, and therefore should not be considered as limiting the present application.

Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

In the description of the embodiments of the present application, it should also be noted that, unless otherwise explicitly stated or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

Example 1:

the utility model provides a but automatically regulated heat preservation device for diesel engine exhaust system, as shown in fig. 1, fig. 2 and fig. 3, diesel engine exhaust system includes engine 1 and tail gas aftertreatment system 2, tail gas aftertreatment system 2 includes oxidation catalyst DOC, particulate filter DPF and selective catalytic reduction device SCR, the front end of tail gas aftertreatment system 2 is connected with engine 1 through blast pipe 3, the rear end of tail gas aftertreatment system 2 is connected with tail pipe 4, but the outside of tail gas aftertreatment system 2 is equipped with automatically regulated heat preservation device.

The automatically adjustable heat preservation device comprises a protective shell 5, an air bag 6, a heat preservation layer 7 and an inflation and deflation pump 9; the protective shell 5 is fixedly sleeved outside the tail gas aftertreatment system 2; the air bag 6 and the heat preservation layer 7 are coated outside the side wall of the tail gas aftertreatment system 2, the outer side of the air bag 6 is connected with the inner side wall of the protective shell 5, and the inner side of the air bag 6 is connected with the heat preservation layer 7; the inflation and deflation pump 9 is connected with the air bag 6 and used for inflating and deflating the air bag 6, the air bag 6 is inflated and expanded to drive the heat insulation layer 7 to contact with the side wall of the tail gas post-treatment system 2, and the air bag 6 is deflated and contracted to drive the heat insulation layer 7 to be far away from the side wall of the tail gas post-treatment system 2, so that a cavity 11 is formed between the heat insulation layer 7 and the side wall of the tail gas post-treatment system 2; be equipped with the through-hole 501 with cavity 11 intercommunication on the protective housing 5, the air can be followed through-hole 501 and circulate in cavity 11 between the lateral wall of tail gas aftertreatment system 2 and heat preservation 7, takes away the heat.

In order to realize the intellectualization of inflation and deflation, the automatic-adjustment heat preservation device also comprises a controller and a temperature sensor, the controller is in communication connection with the temperature sensor and the inflation and deflation pump 9, the temperature sensor is arranged inside the exhaust gas post-treatment system 2 (respectively arranged inside the oxidation catalyst DOC, the particulate filter DPF and the selective catalytic reduction device SCR) and is used for measuring the internal temperature of the exhaust gas post-treatment system 2, the temperature range is preset on the controller, and if one of the temperature sensors monitors that the exhaust temperature reaches the set temperature threshold, the temperature is considered to be higher, the air bag 6 needs to be deflated, the heat dissipation of the tail gas aftertreatment system 2 is convenient, if the exhaust temperature does not reach the set temperature threshold value, the air bag 6 is inflated, so that the heat-insulating layer 7 is close to and coated on the side wall of the tail gas aftertreatment system 2 again to play a role in heat insulation.

As shown in fig. 2, when the temperature is low, the air bag 6 is inflated by the inflation and deflation pump 9, and the expansion of the air bag 6 extrudes the heat insulation layer 7 to be close to the side wall of the tail gas aftertreatment system 2, so that a good heat insulation effect is achieved; as shown in fig. 1, when the temperature is higher, by the gassing of inflation pump 9 in to gasbag 6, the lateral wall that tail gas aftertreatment system 2 was kept away from to gasbag 6 shrink drive heat preservation 7, forms cavity 11 between heat preservation 7 and the lateral wall of tail gas aftertreatment system 2, through-hole 501 and cavity 11 intercommunication on the protective housing 5 to take away the heat by the air of circulation, play the cooling effect.

The protective casing 5 includes a first end surface connected to the exhaust pipe 3 and a second end surface connected to the tail pipe 4, and the through holes 501 are provided on the first end surface and the second end surface.

As shown in fig. 4, in the present embodiment, the through hole 501 is an annular hole, and the annular hole provided on the first end face is concentric with the first end face, and the annular hole provided on the second end face is concentric with the second end face.

In other embodiments, as shown in fig. 5, the through-hole 501 comprises a plurality of openings annularly distributed on the first end face and a plurality of openings annularly distributed on the second end face.

Referring to fig. 3, the number of the airbags 6 is multiple, the shape of a single airbag 6 is as shown in fig. 6, the axial direction of the exhaust gas aftertreatment system 2 is taken as the length direction, the length of the airbag 6 is matched with the length of the exhaust gas aftertreatment system 2, and the airbags 6 are uniformly distributed in the circumferential direction of the exhaust gas aftertreatment system 2. In this embodiment, the number of the airbags 6 is 8, and the airbags are uniformly distributed in a ring shape along the circumferential direction of the exhaust gas aftertreatment system 2.

The adjacent air bags 6 are communicated through a connecting air pipe 10, one side of each air bag 6 is provided with an air port, an inflation and deflation pipe 8 is arranged inside each air port, an inflation and deflation pump 9 is connected with one air bag 6 through the inflation and deflation pipe 8 to inflate and deflate the air bag 6, and the rest air bags 6 can be inflated and deflated in sequence due to the fact that the air bags 6 are communicated through the connecting air pipe 10.

The provision of a plurality of air bags 6 differs from the provision of a single air bag 6 in that: if only one air bag 6 is arranged, all the positions of the air bag 6 are almost simultaneously expanded in the process of inflating the air bag 6, at the moment, the heat-insulating layer 7 is almost simultaneously contracted along the circumferential direction of the exhaust gas post-processor 2, and the heat-insulating layer 7 is easy to generate large folds, so that the wrapping performance of the heat-insulating layer 7 on the exhaust gas post-processor 2 is poor; if be provided with a plurality of gasbags 6, a gasbag 6 links to each other with inflating pump 9 through inflating and deflating pipe 8, remaining gasbag communicates in proper order through connecting trachea 10, at the inflated in-process, gasbag 6 that is connected with inflating and deflating pipe 8 can expand at first, heat preservation 7 that is connected with first gasbag can at first the cladding in the outside of tail gas aftertreatment ware 2, gas can get into second gasbag 6 along connecting trachea 10 afterwards, heat preservation 7 that is connected with second gasbag can continue the cladding in the outside of tail gas aftertreatment ware 2, analogize in proper order, heat preservation 7 can be the cladding in the outside of tail gas aftertreatment ware 2 gradually, heat preservation 7 is better to 2 lateral walls parcel nature of tail gas aftertreatment ware like this, can guarantee the heat insulating ability.

The air bag 6 is a double-layer air bag and is provided with an inner layer and an outer layer, the inner layer is made of a silicon rubber material, the silicon rubber is made of high-temperature vulcanized silicon rubber and has good high-temperature resistance, and the outer layer is formed by compounding oxford fabric and polyester fiber, so that the air bag 6 has good strength and wear resistance.

The insulating layer 7 is made of basalt fiber materials, the main component of the basalt fibers is woven by silica fibers, the materials have high strength and permanent flame retardance, can resist temperature of over 1000 ℃ in a short period, can be used in an environment with the temperature of 760 ℃ for a long time, are thin in wrapping thickness, and can achieve wrapping under the condition of small gaps. The air bag 6 is fixedly bonded with the heat preservation layer 7 through hot melt adhesive, so that the stability of connection between the heat preservation layer 7 and the air bag 6 can be ensured.

The outside of the exhaust pipe 3 and the tail pipe 4 can be directly coated with a heat-insulating layer 7 made of basalt fiber materials to insulate heat. Similarly, the exhaust pipe 3 and the tail pipe 4 may be provided with an automatic temperature control device outside the same as the exhaust gas post-processor 2.

The automatically adjustable heat preservation device arranged outside the exhaust pipe 3 and the tail pipe 4 is similar to the automatically adjustable heat preservation device arranged outside the tail gas aftertreatment system 2 in structure and comprises a protective shell 5, an air bag 6, a heat preservation layer 7 and an inflation and deflation pump 9;

the protective shell 5 is fixedly sleeved outside the exhaust pipe 3 and the tail pipe 4; the air bag 6 and the heat-insulating layer 7 are coated outside the outer walls of the exhaust pipe 3 and the tail pipe 4, the outer side of the air bag 6 is connected with the inner side wall of the protective shell 5, and the inner side of the air bag 6 is connected with the heat-insulating layer 7; the inflation and deflation pump 9 is connected with the air bag 6 and used for inflating and deflating the air bag 6, the air bag 6 is inflated and expanded to drive the heat insulation layer 7 to be in contact with the outer walls of the exhaust pipe 3 and the tail pipe 4, and the air bag 6 is deflated and contracted to drive the heat insulation layer 7 to be far away from the outer walls of the exhaust pipe 3 and the tail pipe 4, so that a cavity 11 is formed between the heat insulation layer 7 and the outer walls of the exhaust pipe 3 and the tail pipe 4; the protective shell 5 is provided with a through hole 501 communicated with the cavity 11, and air can circulate in the cavity 11 between the outer walls of the exhaust pipe 3 and the tail pipe 4 and the heat-insulating layer 7 along the through hole 501 to take away heat.

The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims (10)

1. an automatically adjustable thermal insulation device for a diesel engine exhaust system, characterized in that the diesel engine exhaust system comprises an engine (1) and an exhaust gas aftertreatment system (2), the exhaust gas aftertreatment system (2) The front end of the exhaust gas after-treatment system (2) is connected with the engine (1) through the exhaust pipe (3), and the rear end of the exhaust gas after-treatment system (2) is connected with a tail pipe (4); an automatic adjustment thermal insulation device, the automatically adjustable thermal insulation device comprises a protective shell (5), an air bag (6), a thermal insulation layer (7) and an inflation and deflation pump (9); The protective casing (5) is fixedly sleeved and installed on the outside of the exhaust gas after-treatment system (2); The airbag (6) and the thermal insulation layer (7) are covered on the outside of the side wall of the exhaust gas after-treatment system (2). The inner side of (6) is connected with the insulation layer (7); The inflation and deflation pump (9) is connected with the airbag (6), and is used for inflating and deflating the airbag (6). side wall, the airbag (6) deflated and contracted to drive the thermal insulation layer (7) away from the side wall of the exhaust gas aftertreatment system (2), so that the space between the thermal insulation layer (7) and the side wall of the exhaust gas aftertreatment system (2) is forming a cavity (11); The protective casing (5) is provided with a through hole (501) communicating with the cavity (11). 2. The self-adjustable thermal insulation device for diesel exhaust system according to claim 1, wherein the self-adjustable thermal insulation device further comprises a controller and a temperature sensor, the controller and the temperature sensor Communication connection with the charging and discharging pump (9), the temperature sensor is installed inside the exhaust gas after-treatment system (2), and is used for measuring the internal temperature of the exhaust gas after-treatment system (2), and the controller is based on the temperature measured by the temperature sensor. and pre-set temperature range to control the charge and discharge pump (9). 3. The self-adjustable heat preservation device for diesel exhaust system according to claim 1, characterized in that, the number of the airbags (6) is multiple, and the shaft of the exhaust gas aftertreatment system (2) The longitudinal direction is the length direction, the length of the airbag (6) is matched with the length of the exhaust gas aftertreatment system (2), and the plurality of airbags (6) are evenly distributed in the circumferential direction of the exhaust gas aftertreatment system (2). 4. A kind of self-adjustable heat preservation device for diesel engine exhaust system according to claim 3, is characterized in that, between adjacent airbags (6) is communicated by connecting air pipe (10), and the inflation pump (9) ) is connected with one of the air bags (6) through the inflation and deflation tube (8). 5. The self-adjustable thermal insulation device for diesel exhaust system according to claim 3, characterized in that, the protective housing (5) comprises a first end face connecting the exhaust pipe (3) and a connection On the second end face of the tail pipe (4), the through hole (501) is provided on the first end face and the second end face. 6. The self-adjustable heat preservation device for diesel exhaust system according to claim 5, characterized in that the through hole (501) is an annular hole, and the annular hole on the first end face is connected to the first end surface. One end face is concentric, and the annular hole provided on the second end face is concentric with the second end face. 7. The self-adjustable heat preservation device for a diesel exhaust system according to claim 5, wherein the through hole (501) comprises a plurality of openings, and the plurality of openings are annularly distributed in the first On the end face, a plurality of openings are annularly distributed on the second end face. 8. The self-adjustable thermal insulation device for diesel exhaust system according to claim 1, wherein the air bag (6) is a double-layer air bag, the inner layer is made of silicone rubber material, and the outer layer is made of Oxford Fabric and polyester fiber composite. 9. A kind of self-adjustable thermal insulation device for diesel engine exhaust system according to claim 1, is characterized in that, the material of described thermal insulation layer (7) is basalt fiber material, air bag (6) and thermal insulation layer ( 7) Fixed and bonded by hot melt adhesive. 10. The self-adjustable thermal insulation device for diesel exhaust system according to claim 1, characterized in that a thermal insulation layer (7) is provided on the outside of the exhaust pipe (3) and the tail pipe (4). ) or an automatically adjustable heat preservation device, the automatically adjustable heat preservation device includes a protective casing (5), an air bag (6), a heat preservation layer (7) and an inflation and deflation pump (9); The protective casing (5) is fixedly sleeved and installed on the outside of the exhaust pipe (3) and the tail pipe (4); The airbag (6) and the thermal insulation layer (7) are wrapped around the outer walls of the exhaust pipe (3) and the tail pipe (4), and the outer side of the airbag (6) is connected to the inner side wall of the protective shell (5). , the inner side of the airbag (6) is connected with the thermal insulation layer (7); The inflating and deflating pump (9) is connected with the airbag (6) and is used for inflating and deflating the airbag (6). The outer wall of the pipe (4), the airbag (6) deflated and contracted to drive the insulation layer (7) away from the outer wall of the exhaust pipe (3) and the tail pipe (4), so that the insulation layer (7) and the exhaust pipe ( 3) A cavity (11) is formed between the outer wall of the tail pipe (4); The protective casing (5) is provided with a through hole (501) communicating with the cavity (11).

Images