阅读说明：本技术 一种v型柴油机增压系统及其控制策略 (V-shaped diesel engine supercharging system and control strategy thereof ) 是由 王志磊 董飞莹 史四强 张弛 宋杨 于 2021-08-31 设计创作，主要内容包括：本发明公开了一种V型柴油机增压系统及其控制策略,包括V型机体,V型机体的上端设置有支架,所述支架的上端对称设置有两个相同的增压机构,所述增压机构包括低压增压器Ⅰ、空冷器Ⅰ、高压增压器、空冷器Ⅱ、低压增压器Ⅱ、空冷器Ⅲ和集气管,所述低压增压器Ⅰ和低压增压器Ⅱ分别通过进气管Ⅰ与空冷器Ⅰ和空冷器Ⅱ连接,空冷器Ⅰ和空冷器Ⅱ分别与高压增压器连接,所述低压增压器Ⅱ与空冷器Ⅲ连接,空冷器Ⅲ与进气歧管连接,所述集气管设置在两个增压机构之间,本V型柴油机增压系统及其控制策略可以同时适用于高海拔和低海拔环境下的增压器作业,有利于提高柴油机运行可靠性和稳定性。(The invention discloses a V-shaped diesel engine supercharging system and a control strategy thereof, comprising a V-shaped engine body, wherein the upper end of the V-shaped engine body is provided with a bracket, two same supercharging mechanisms are symmetrically arranged at the upper end of the bracket, each supercharging mechanism comprises a low-pressure supercharger I, an air cooler I, a high-pressure supercharger, an air cooler II, a low-pressure supercharger II, an air cooler III and a gas collecting pipe, the low-pressure supercharger I and the low-pressure supercharger II are respectively connected with an air cooler I and an air cooler II through an air inlet pipe I, the air cooler I and the air cooler II are respectively connected with a high-pressure supercharger, the low-pressure supercharger II is connected with the air cooler III, the air cooler III is connected with the air inlet manifold, the gas collecting pipe is arranged between the two supercharging mechanisms, and the V-shaped diesel engine supercharging system and the control strategy thereof can be simultaneously suitable for supercharger operation under high-altitude and low-altitude environments, and are favorable for improving the operation reliability and stability of a diesel engine.)

1. The utility model provides a V type diesel engine turbocharging system, includes V type organism (10), and the upper end of V type organism (10) is provided with support (12), its characterized in that: the upper end symmetry of support (12) is provided with two the same booster mechanisms, booster mechanism includes low pressure booster I (1), air cooler I (3), high pressure booster (4), air cooler II (6), low pressure booster II (7), air cooler III (8) and collecting pipe (13), low pressure booster I (1) and low pressure booster II (7) are connected with air cooler I (3) and air cooler II (6) through intake pipe I (2) respectively, air cooler I (3) and air cooler II (6) are connected with high pressure booster (4) respectively, low pressure booster II (7) are connected with air cooler III (8), air cooler III (8) are connected with intake manifold (9), collecting pipe (13) set up between two booster mechanisms, the one end of collecting pipe (13) is connected with blast pipe (11), collecting pipe (13) are connected with high pressure booster (4) through first exhaust branch pipe (14), the high-pressure supercharger (4) and the low-pressure supercharger I (1) and the low-pressure supercharger II (7) are respectively provided with a corresponding exhaust pipeline and an electromagnetic butterfly valve according to different working altitudes, and the exhaust pipeline and the electromagnetic butterfly valve are used for improving air inlet density.

2. The V-diesel engine boosting system according to claim 1, wherein: under high altitude environment, the exhaust end of high pressure booster (4) is connected with second exhaust branch (15) and fourth exhaust branch (20) respectively, second exhaust branch (15) are connected with low pressure booster I (1), are connected through third exhaust branch (16) between second exhaust branch (15) and low pressure booster II (7), be provided with electromagnetic butterfly valve II (18) on fourth exhaust branch (20), and electromagnetic butterfly valve II (18) are located behind the tie point of second exhaust branch (15) and high pressure booster (4), are provided with electromagnetic butterfly valve III (19) on second exhaust branch (15), and electromagnetic butterfly valve III (19) are located behind the tie point of third exhaust branch (16) and second exhaust branch (15), are provided with electromagnetic butterfly valve I (17) on third exhaust branch (15).

3. The control strategy for a V-type diesel engine boosting system according to claim 2, wherein: under the high-altitude environment, the ECU selects different supercharging modes according to the rotation speed and the power of the diesel engine and the engine under different working conditions, and the control strategy is as follows:

a. when the engine is in a low-load working condition, selecting a supercharger mode:

and when the diesel engine is in a low-load state, the quantity of tail gas generated by combustion is small, the electromagnetic butterfly valve II (18) is opened, the electromagnetic butterfly valve I (17) and the electromagnetic butterfly valve III (19) are closed, and the tail gas is exhausted into the atmosphere through the fourth exhaust branch pipe (20).

b. When the engine is in a normal working condition, the mode of the supercharger is selected as follows:

and opening the electromagnetic butterfly valve I (17) or the electromagnetic butterfly valve III (19), and finally exhausting the tail gas into the atmosphere through the low-pressure supercharger I (1) or the low-pressure supercharger II (7).

c. When the engine is in a high-load working condition, the mode of the supercharger is selected as follows:

and opening the electromagnetic butterfly valve I (17) and the electromagnetic butterfly valve III (19), enabling the high-temperature and high-pressure gas flowing through the high-pressure supercharger (4) to respectively flow into the low-pressure supercharger I (1) and the low-pressure supercharger II (7), then converging the high-temperature and high-pressure gas into a gas compressor of the high-pressure supercharger (4), and finally entering the gas inlet manifold (9).

4. The V-diesel engine boosting system according to claim 1, wherein: under the low-altitude environment, gas collecting pipe (13) are connected with low pressure booster I (1) through fifth exhaust branch pipe (21), be connected with low pressure booster II (7) through sixth exhaust branch pipe (22) on fifth exhaust branch pipe (21), be connected through seventh exhaust branch pipe (23) between sixth exhaust branch pipe (22) and high pressure booster (4), the end of giving vent to anger of low pressure booster I (1) and low pressure booster II (7) all is connected with eighth exhaust branch pipe (24), be provided with electromagnetism butterfly valve IV (25) on fifth exhaust branch pipe (21), electromagnetism butterfly valve IV (25) are located before the tie point V of fifth exhaust branch pipe (21) and sixth exhaust branch pipe (22), be provided with electromagnetism butterfly valve (26) on seventh exhaust branch pipe (21), be provided with electromagnetism butterfly valve VI (27) on sixth exhaust branch pipe (22), electromagnetism butterfly valve VI (27) are located the tie point V of sixth exhaust branch pipe (22) and seventh exhaust branch pipe (23) And (6) finally.

5. The V-type diesel engine boosting system and the control strategy thereof according to claim 4, wherein: under the low-altitude environment, the ECU selects different supercharging modes according to the rotation speed and the power of the diesel engine and the engine under different working conditions, and the control strategy is as follows:

A. when the engine is in a low-load working condition, selecting a supercharger mode:

and (3) closing the electromagnetic butterfly valve V (26), opening the electromagnetic butterfly valve IV (25) or the electromagnetic butterfly valve VI (27) and discharging tail gas into the atmosphere after the tail gas enters the low-pressure supercharger I (1) or the low-pressure supercharger II (7) in a low-load state of the diesel engine.

B. When the engine is in a normal working condition, the mode of the supercharger is selected as follows:

along with the gradual lifting of the power of the diesel engine from low load, an electromagnetic butterfly valve V (26) is closed, an electromagnetic butterfly valve IV (25) and an electromagnetic butterfly valve VI (27) are opened simultaneously, and tail gas is exhausted into the atmosphere after passing through turbines of a low-pressure supercharger I (1) and a low-pressure supercharger II (7), so that the air inflow is improved.

C. When the engine is in a high-load working condition, the mode of the supercharger is selected as follows:

when the diesel engine operates in a high-load mode, the exhaust gas discharge flow is further increased, the electromagnetic butterfly valve V (26) is opened and closed, the electromagnetic butterfly valve IV (25) and the electromagnetic butterfly valve VI (27) are closed, and air enters the atmosphere through the turbine of the high-pressure supercharger (4).

Technical Field

The invention relates to the technical field of diesel engines, in particular to a V-shaped diesel engine supercharging system and a control strategy thereof.

Background

The internal-combustion engine adopts turbocharging technology to improve the power density of diesel engine and reduce pollutant emission, but because the booster is rotatory for the impeller, and the diesel engine is reciprocating linear motion, under the condition of full operating mode, it is comparatively difficult that both will reach full matching, especially to the low altitude environment of the low high altitude environment of air rarefied and atmospheric pressure and oxygen content height and atmospheric pressure, it is difficult to share the same internal-combustion engine between the two, and single or a plurality of booster arranges alone hardly to satisfy the time needs, lead to combustion efficiency low, it is low to admit air the density characteristic.

Disclosure of Invention

The invention aims to overcome the defects in the prior art, provides a V-shaped diesel engine supercharging system and a control strategy thereof, can be simultaneously suitable for supercharger operation in high altitude and low altitude environments, is beneficial to improving the running reliability and stability of a diesel engine, and can effectively solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a V-shaped diesel engine supercharging system comprises a V-shaped engine body, wherein a support is arranged at the upper end of the V-shaped engine body, two identical supercharging mechanisms are symmetrically arranged at the upper end of the support and comprise a low-pressure supercharger I, an air cooler I, a high-pressure supercharger, an air cooler II, a low-pressure supercharger II, an air cooler III and an air collecting pipe, the low-pressure supercharger I and the low-pressure supercharger II are respectively connected with the air cooler I and the air cooler II through an air inlet pipe I, the air cooler I and the air cooler II are respectively connected with the high-pressure supercharger, the low-pressure supercharger II is connected with the air cooler III, the air cooler III is connected with an air inlet manifold, the air collecting pipe is arranged between the two supercharging mechanisms, one end of the air collecting pipe is connected with an exhaust pipe, the air collecting pipe is connected with the high-pressure supercharger through a first exhaust branch pipe, the high-pressure supercharger is respectively provided with a corresponding exhaust pipe and an electromagnetic butterfly valve according to different working altitudes between the low-pressure supercharger I and the low-pressure supercharger II, for increasing the charge density.

According to a preferable technical scheme of the invention, under a high-altitude environment, an exhaust end of the high-pressure supercharger is respectively connected with a second exhaust branch pipe and a fourth exhaust branch pipe, the second exhaust branch pipe is connected with the low-pressure supercharger I, the second exhaust branch pipe is connected with the low-pressure supercharger II through a third exhaust branch pipe, the fourth exhaust branch pipe is provided with an electromagnetic butterfly valve II, the electromagnetic butterfly valve II is positioned behind a connection point of the second exhaust branch pipe and the high-pressure supercharger, the second exhaust branch pipe is provided with an electromagnetic butterfly valve III, the electromagnetic butterfly valve III is positioned behind a connection point of the third exhaust branch pipe and the second exhaust branch pipe, and the third exhaust branch pipe is provided with an electromagnetic butterfly valve I.

A control strategy of a V-shaped diesel engine supercharging system is characterized in that under the high-altitude environment, an ECU selects different supercharging modes according to the rotation speed and power of a diesel engine and different working conditions of an engine, and the control strategy is as follows:

a. when the engine is in a low-load working condition, selecting a supercharger mode:

the diesel engine is under the low-load state, and the produced tail gas volume of burning is less, opens electromagnetism butterfly valve II, closes electromagnetism butterfly valve I and electromagnetism butterfly valve III, and tail gas is discharged into the atmosphere through the fourth exhaust branch pipe.

b. When the engine is in a normal working condition, the mode of the supercharger is selected as follows:

and opening the electromagnetic butterfly valve I or the electromagnetic butterfly valve III, and finally exhausting the tail gas into the atmosphere through the low-pressure supercharger I or the low-pressure supercharger II.

c. When the engine is in a high-load working condition, the mode of the supercharger is selected as follows:

and opening the electromagnetic butterfly valve I and the electromagnetic butterfly valve III, enabling the high-temperature and high-pressure gas flowing through the high-pressure supercharger to flow into the low-pressure supercharger I and the low-pressure supercharger II respectively, then converging the high-temperature and high-pressure gas into a gas compressor of the high-pressure supercharger, and finally entering the gas inlet manifold.

According to a preferable technical scheme, in a low-altitude environment, the gas collecting pipe is connected with a low-pressure supercharger I through a fifth exhaust branch pipe, the fifth exhaust branch pipe is connected with a low-pressure supercharger II through a sixth exhaust branch pipe, the sixth exhaust branch pipe is connected with the high-pressure supercharger through a seventh exhaust branch pipe, gas outlet ends of the low-pressure supercharger I and the low-pressure supercharger II are both connected with an eighth exhaust branch pipe, the fifth exhaust branch pipe is provided with an electromagnetic butterfly valve IV, the electromagnetic butterfly valve IV is located in front of a connection point of the fifth exhaust branch pipe and the sixth exhaust branch pipe, the seventh exhaust branch pipe is provided with an electromagnetic butterfly valve V, the sixth exhaust branch pipe is provided with an electromagnetic butterfly valve VI, and the electromagnetic butterfly valve VI is located behind a connection point of the sixth exhaust branch pipe and the seventh exhaust branch pipe.

A V-type diesel engine supercharging system and a control strategy thereof are disclosed, under the low altitude environment, an ECU selects different supercharging modes according to the rotation speed and power of a diesel engine and different working conditions of an engine, and the control strategy is as follows:

A. when the engine is in a low-load working condition, selecting a supercharger mode:

and (3) closing the electromagnetic butterfly valve V, opening the electromagnetic butterfly valve IV or the electromagnetic butterfly valve VI, introducing tail gas into the low-pressure supercharger I or the low-pressure supercharger II and finally exhausting the tail gas into the atmosphere in the low-load state of the diesel engine.

B. When the engine is in a normal working condition, the mode of the supercharger is selected as follows:

and (3) closing the electromagnetic butterfly valve V along with the gradual increase of the power of the diesel engine from low load, simultaneously opening the electromagnetic butterfly valve IV and the electromagnetic butterfly valve VI, and exhausting tail gas into the atmosphere after passing through the turbines of the low-pressure supercharger I and the low-pressure supercharger II so as to improve the air inflow.

C. When the engine is in a high-load working condition, the mode of the supercharger is selected as follows:

when the diesel engine operates in a high-load mode, the exhaust gas discharge flow is further increased, the electromagnetic butterfly valve V is opened and closed, the electromagnetic butterfly valve IV and the electromagnetic butterfly valve VI are closed, and air enters the atmosphere through the turbine of the high-pressure supercharger.

Compared with the prior art, the invention has the beneficial effects that: the V-shaped diesel engine supercharging system and the control strategy thereof have the advantages of ingenious conception and reasonable design, can be simultaneously suitable for supercharger operation in high altitude and low altitude environments, divide the supercharger control strategy into three stages of low-load operation, normal operation and high-load operation in the high altitude environment or the low altitude environment, effectively improve the air intake density characteristic of an air intake diesel engine, balance pressure discharge, and effectively improve the operation reliability and stability of the diesel engine as all superchargers operate.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of an exhaust line in a high altitude environment;

fig. 3 is a schematic view of the exhaust line in a low altitude environment.

In the figure: 1 low-pressure booster I, 2 air inlet pipe I, 3 air cooler I, 4 high-pressure booster, 5 air inlet pipe II, 6 air cooler II, 7 low-pressure booster II, 8 air cooler III, 9 air inlet manifold, 10V type organism, 11 exhaust pipe, 12 supports, 13 gas collecting pipes, 14 first exhaust branch pipes, 15 second exhaust branch pipes, 16 third exhaust branch pipes, 17 electromagnetic butterfly valves I, 18 electromagnetic butterfly valves II, 19 electromagnetic butterfly valves III, 20 fourth exhaust branch pipes, 21 fifth exhaust branch pipes, 22 sixth exhaust branch pipes, 23 seventh exhaust branch pipes, 24 eighth exhaust branch pipes, 25 electromagnetic butterfly valves IV, 26 electromagnetic butterfly valves V and 27 electromagnetic butterfly valves VI.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1: referring to fig. 1, the present invention provides a technical solution: the utility model provides a V type diesel engine turbocharging system, including V type organism 10, the upper end of V type organism 10 is provided with support 12, the upper end symmetry of support 12 is provided with two the same supercharging mechanism, supercharging mechanism includes low pressure booster I1, air cooler I3, high pressure booster 4, air cooler II 6, low pressure booster II 7, air cooler III 8 and collecting pipe 13, low pressure booster I1 and low pressure booster II 7 are connected with air cooler I3 and air cooler II 6 through intake pipe I2 respectively, air cooler I3 and air cooler II 6 are connected with high pressure booster 4 respectively, low pressure booster II 7 is connected with air cooler III 8, air cooler III 8 is connected with intake manifold 9, collecting pipe 13 sets up between two mechanisms, the one end of collecting pipe 13 is connected with booster pipe 11, collecting pipe 13 is connected with high pressure booster 4 through first exhaust branch pipe 14, high pressure booster 4 respectively with low pressure booster I1 and low pressure booster II 7 according to the difference of work elevation And a corresponding exhaust pipeline and an electromagnetic butterfly valve are arranged for improving the air intake density.

As shown in fig. 2, in a high altitude environment, an exhaust end of the high pressure supercharger 4 is connected to a second exhaust branch pipe 15 and a fourth exhaust branch pipe 20, the second exhaust branch pipe 15 is connected to the low pressure supercharger i 1, the second exhaust branch pipe 15 is connected to the low pressure supercharger ii 7 through a third exhaust branch pipe 16, an electromagnetic butterfly valve ii 18 is arranged on the fourth exhaust branch pipe 20, the electromagnetic butterfly valve ii 18 is located behind a connection point of the second exhaust branch pipe 15 and the high pressure supercharger 4, an electromagnetic butterfly valve iii 19 is arranged on the second exhaust branch pipe 15, the electromagnetic butterfly valve iii 19 is located behind a connection point of the third exhaust branch pipe 16 and the second exhaust branch pipe 15, an electromagnetic butterfly valve i 17 is arranged on the third exhaust branch pipe 15, and a control strategy thereof is as follows: the ECU selects different supercharging modes according to the rotation speed and power of the diesel engine and the engine under different working conditions, and the control strategy is as follows:

a. when the engine is in a low-load working condition, selecting a supercharger mode:

in order to generate higher air supercharging pressure, the high-pressure supercharger 4 is easy to generate higher rotating speed under the condition of smaller exhaust flow because the turbine rotating inertia is small, so that the supercharging pressure at the air compressing end is increased, the electromagnetic butterfly valve II 18 is opened, the electromagnetic butterfly valve I17 and the electromagnetic butterfly valve III 19 are closed, and the tail gas is exhausted into the atmosphere through the fourth exhaust branch pipe 20.

b. When the engine is in a normal working condition, the mode of the supercharger is selected as follows:

along with the gradual promotion of diesel engine power from the low-load, the burning discharge flow increases gradually, and high pressure booster 4 can not satisfy the demand, opens electromagnetism butterfly valve I17 or electromagnetism butterfly valve III 19, and tail gas passes through I1 of low pressure booster or II 7 of low pressure booster and discharges into the atmosphere at last.

c. When the engine is in a high-load working condition, the mode of the supercharger is selected as follows:

when the diesel engine operates in a high-load mode, the exhaust emission flow is large, a low-pressure supercharger and a high-pressure supercharger 4 cannot meet actual requirements, an electromagnetic butterfly valve I17 and an electromagnetic butterfly valve III 19 are opened, high-temperature high-pressure gas flowing through the high-pressure supercharger 4 flows into a low-pressure supercharger I1 and a low-pressure supercharger II 7 respectively, then flows into a gas compressor of the high-pressure supercharger 4, and finally enters an air inlet manifold 9.

According to different working condition load characteristics, a grading pressurization strategy is adopted: according to the invention, a supercharger control strategy is divided into three stages according to the running characteristics of the supercharger, the fuel oil emission performance and the plateau environment characteristics, when the diesel engine is in low load, the supercharger is operated in a high-efficiency area, and one high-pressure supercharger 4 is selected for operation; with the increase of the load, a high-pressure supercharger 4 and a low-pressure supercharger are selected to be connected in series for operation, and two-stage supercharging is carried out; when the full load is reached, the three superchargers operate simultaneously, the high-pressure supercharger 4, the low-pressure supercharger I1 and the low-pressure supercharger II 7 are connected in series, and the low-pressure supercharger I1 and the low-pressure supercharger II 7 operate in parallel.

The invention ensures the balanced operation characteristics of all superchargers: high-temperature high-pressure gas that two booster mechanisms burnt gets into gas collecting pipe 13 through blast pipe 11, communicates two booster mechanisms to reach pressure balance, prevent because two booster mechanisms burn unevenly to cause the exhaust flow inhomogeneous, thereby cause all superchargers operation inconsistent, can effectively provide diesel engine operational reliability and stability.

The invention ensures that the intake density characteristic is improved: because I1 of low pressure booster and II 7 of low pressure booster do work to the air, air temperature can promote, the design has air cooler I3 and air cooler II 6 to carry out air cooling, can reduce air temperature and increase air density, and then increases the air input, then after air admission high pressure booster 4, III 8 of air cooler cool off pressurized air once more, and air admission air intake manifold 9 at last.

Example 2: as shown in fig. 3, the difference from embodiment 1 is that, in a low altitude environment, the gas collecting pipe 13 is connected to the low pressure supercharger i 1 through a fifth exhaust branch pipe 21, the fifth exhaust branch pipe 21 is connected to the low pressure supercharger ii 7 through a sixth exhaust branch pipe 22, the sixth exhaust branch pipe 22 is connected to the high pressure supercharger 4 through a seventh exhaust branch pipe 23, the gas outlet ends of the low pressure supercharger i 1 and the low pressure supercharger ii 7 are both connected to an eighth exhaust branch pipe 24, the fifth exhaust branch pipe 21 is provided with an electromagnetic butterfly valve iv 25, the electromagnetic butterfly valve iv 25 is located before the connection point of the fifth exhaust branch pipe 21 and the sixth exhaust branch pipe 22, the seventh exhaust branch pipe 21 is provided with an electromagnetic butterfly valve v 26, the sixth exhaust branch pipe 22 is provided with an electromagnetic butterfly valve vi 27, and the electromagnetic butterfly valve vi 27 is located behind the connection point of the sixth exhaust branch pipe 22 and the seventh exhaust branch pipe 23, and the control strategy is as follows: the ECU selects different supercharging modes according to the rotation speed and power of the diesel engine and the engine under different working conditions, and the control strategy is as follows:

A. when the engine is in a low-load working condition, selecting a supercharger mode:

under the condition of low load of the diesel engine, compared with a high-altitude area, the air density and oxygen content in the low-altitude area are high, high-temperature and high-pressure gas generated by combustion is more, the turbine rotational inertia of the low-pressure supercharger is larger than that of the low-pressure supercharger, the low-pressure supercharger is more easily matched with a MAP (MAP) diagram of the low-pressure supercharger, the electromagnetic butterfly valve V26 is closed, the electromagnetic butterfly valve IV 25 or the electromagnetic butterfly valve VI 27 is opened, and tail gas enters the low-pressure supercharger I1 or the low-pressure supercharger II 7 and is finally exhausted into the atmosphere.

B. When the engine is in a normal working condition, the mode of the supercharger is selected as follows:

along with the gradual promotion of diesel engine power from the low-load, the burning discharge flow increases gradually, and high pressure booster 4 can not satisfy the demand, opens electromagnetism butterfly valve IV 25 and electromagnetism butterfly valve VI 27 simultaneously, and tail gas passes through I1 of low pressure booster and II 7's turbine back exhaust in the atmosphere to improve the air input.

C. When the engine is in a high-load working condition, the mode of the supercharger is selected as follows:

when the diesel engine operates in a high-load mode, the exhaust emission flow is further increased, the low-pressure supercharger I1 and the low-pressure supercharger II 7 cannot meet actual requirements, the electromagnetic butterfly valve V26 is opened and closed, the electromagnetic butterfly valve IV 25 and the electromagnetic butterfly valve VI 27 are closed, and air enters the atmosphere through the turbine of the high-pressure supercharger 4.

According to different working condition load characteristics, the invention adopts a grading pressurization strategy: according to the invention, a supercharger control strategy is divided into three stages according to the running characteristics of the supercharger, the fuel oil emission performance and the characteristics of a low altitude environment, the supercharger is operated in a high-efficiency area when the diesel engine is in low load, one low-pressure supercharger is selected for operation, two high-pressure superchargers 4 in two supercharging mechanisms are operated in parallel along with the increase of the load to carry out successive supercharging, and one low-pressure supercharger and one high-pressure supercharger 4 carry out two-stage supercharging when the full load is reached.

The invention ensures the balanced operation characteristics of all superchargers: high-temperature high-pressure gas combusted in the two supercharging mechanisms enters the gas collecting pipe 13 through the exhaust pipe 11, the exhaust systems of the two supercharging mechanisms are communicated to achieve pressure equalization, the problem that due to the fact that the two supercharging mechanisms are not combusted uniformly, exhaust flow is not uniform is solved, operation of all superchargers is inconsistent is solved, and the operation reliability and stability of a diesel engine can be effectively improved.

The invention ensures that the intake density characteristic is improved: after the air enters the low-pressure supercharger I1 and the low-pressure supercharger II 7, because the air compressor 3 of the low-pressure supercharger I and the air compressor 12 of the low-pressure supercharger II apply work to the air, the air temperature can be increased, the air cooler I3 and the air cooler II 6 are subjected to air cooling, the air temperature can be reduced, the air density can be increased, the air inflow is increased, then after the air enters the high-pressure supercharger 4, the air cooler III 8 cools the supercharged air again, and finally the air enters the air inlet manifold 9.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.