CN110836141B

CN110836141B - Method and system for increasing exhaust pressure of engine

Info

Publication number: CN110836141B
Application number: CN201810935370.2A
Authority: CN
Inventors: 杨洲
Original assignee: Shanghai Universoon Auto Parts Co Ltd
Current assignee: Shanghai Youshun Automobile Technology Co.,Ltd.
Priority date: 2018-08-16
Filing date: 2018-08-16
Publication date: 2020-12-08
Anticipated expiration: 2038-08-16
Also published as: CN110836141A

Abstract

The invention provides a method and a system for increasing the exhaust pressure of an engine, which are used for the engine with a turbocharger, wherein an exhaust runner of the engine is arranged between an exhaust manifold of the engine and a turbine of the turbocharger, a rotatable guide door is arranged in the exhaust runner, and the inner side surface of the guide door faces the inner wall of the exhaust runner when the guide door is at the initial position without rotation; the compressed air is sprayed from the outside of the exhaust flow passage to the inner side surface of the guide door positioned in the exhaust flow passage by using an air spraying mechanism, the guide door is driven to rotate, the included angle between the guide door and the inner wall of the exhaust flow passage is increased, the flowing direction and the flowing speed of the exhaust airflow of the engine in the exhaust flow passage are changed, the flow area of the exhaust flow passage is reduced, and the exhaust pressure of the engine is increased. The system of the invention has compact structure and small occupied space, can be arranged at the upstream of the turbine, fully plays the role of the turbocharger, reduces the delay of the turbine, increases the exhaust gas circulation, reduces the exhaust emission of the engine and improves the braking power of the engine.

Description

Method and system for increasing exhaust pressure of engine

Technical Field

The invention relates to the field of engines, in particular to a method and a system for increasing exhaust pressure of an engine.

Background

In the prior art, increasing the exhaust pressure of an engine is widely used in the fields of emission treatment (exhaust gas recirculation) of the engine, engine braking, and the like. The main difference between engine braking and conventional ignition is that braking does not involve fuel injection or combustion, and the engine producing power is temporarily converted into an energy-absorbing air compressor. During braking, in addition to the conventional opening of the intake and exhaust valves during the intake and exhaust strokes, the engine brake reopens the exhaust valve during the compression stroke of the engine piston, allowing the compressed gas (air when braking) to be released, and the energy absorbed by the compressed gas during the compression stroke of the engine cannot be returned to the engine piston during the subsequent expansion (work) stroke, but is released through the exhaust and heat dissipation system of the engine. The net result is effective engine braking, slowing the vehicle.

The power and load of engine braking are increased along with the increase of the rotating speed, the engine mostly runs at the middle and low rotating speeds in practical use, and how to improve the engine braking power at the middle and low rotating speeds is urgent under the premise of not increasing the braking load (without overload). The traditional method is combined braking, and exhaust back pressure braking (out-cylinder braking) is added on the basis of compression release, for example, an exhaust butterfly valve is added, so that the exhaust pressure of an engine is increased. The combined braking can indeed improve the braking power of medium and low rotating speeds, reduce the braking load and eliminate the braking noise. However, almost all back pressure control devices (such as exhaust butterfly valves) cannot be installed upstream of the turbine of the turbocharger due to their bulky mechanisms (due to the side effects of turbine lag). The back pressure control device mounted on the exhaust tailpipe downstream of the turbine greatly reduces or even completely shuts off the exhaust gas flow, causing the turbocharger to be inoperative, reducing or even eliminating the intake pressure and flow and the corresponding cooling effect, causing the exhaust temperature to increase, causing overheating of certain engine components, such as the fuel injectors.

As early as 1983, U.S. patent No. 4,395,884 disclosed the use of a splitter valve upstream of the turbine of a turbocharger to combine the exhaust gas flows entering two turbine inlet passages into one turbine inlet passage, change the direction and speed of the exhaust gas flow, increase the turbine speed, increase the intake and exhaust pressures and the engine braking power. However, the splitter valve is not a product due to the limited space upstream of the turbine, its complex mechanism, large size, and difficult control.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present invention provides a method and a system for increasing exhaust pressure of an engine, which are used to solve the technical problems of the prior art, such as complicated mechanism, high cost, large volume, difficult control of the engine back pressure control device, non-operation of the turbocharger caused by the back pressure control device, too high exhaust temperature of the engine at high rotation speed, easy overheating of the nozzle tip of the fuel nozzle, etc.

In order to achieve the above and other related objects, the present invention provides a method for increasing exhaust pressure of an engine having a turbocharger, the engine having an exhaust flow passage between an exhaust manifold and a turbine of the turbocharger, wherein an air injection mechanism is used to inject compressed air from outside the exhaust flow passage to a rotatable guide gate located in the exhaust flow passage, the guide gate is driven to rotate in the exhaust flow passage, the flowing direction and speed of exhaust gas flow of the engine in the exhaust flow passage are changed, the flow area of the exhaust flow passage is reduced, and the exhaust pressure in the exhaust flow passage upstream of the guide gate is increased.

Preferably, the exhaust gas flow passage includes an inlet passage of a turbine of the turbocharger, the guide gate is located in the inlet passage of the turbine of the turbocharger, a hinge of the guide gate is disposed at a junction of an outlet of the exhaust manifold and an inlet of the turbine of the turbocharger, the guide gate is rotatable about the hinge in the inlet passage of the turbine, an inner side surface of the guide gate faces an inner wall of the exhaust gas flow passage when the guide gate is in a non-rotational initial position, and the compressed air is sprayed on the inner side surface of the guide gate.

Preferably, the air injection means injects the compressed air to an inner surface of the guide door in the exhaust runner at a position where an outlet of the exhaust manifold is connected to an inlet of a turbine of the turbocharger.

Preferably, the turbine of the turbocharger has two inlet passages, and a guide door is arranged in each inlet passage of the turbine.

Preferably, the two guide doors in the two inlet passages of the turbine can rotate independently or rotate together simultaneously.

Preferably, the air injection mechanism comprises a power source and a control valve, the power source comprises an air compressor or an air storage tank, the air compressor or the air storage tank generates the compressed air, and the control valve controls the injection time and the flow of the compressed air.

The invention also provides a system for increasing the exhaust pressure of an engine, which is used for the engine with a turbocharger, an exhaust runner is arranged between an exhaust manifold of the engine and a turbine of the turbocharger, and the system is characterized in that: the system for increasing the exhaust pressure of the engine comprises a guide door and an air injection mechanism, the guide door is rotatably arranged in the exhaust runner, when the guide door is at a non-rotating initial position, the inner side surface of the guide door faces the inner wall of the exhaust runner, the air injection mechanism injects compressed air from the outer side of the exhaust runner to the inner side surface of the guide door positioned in the exhaust runner, the guide door is driven to rotate, the guide door is increased, the included angle between the inner wall of the exhaust runner is increased, the flow direction of the exhaust airflow of the engine in the exhaust runner is changed, the flow area of the exhaust runner is reduced, and the exhaust pressure in the upstream exhaust runner of the guide door is increased.

Preferably, the inner side surface of the guide door can be in different shapes, including a plane, a folded surface, a concave surface, a combined surface or other curved surfaces.

Preferably, the exhaust gas flow path comprises an inlet passage of a turbine of the turbocharger, the guide gate is located in the inlet passage of the turbine, a hinge of the guide gate is arranged at a junction of an outlet of the exhaust manifold and an inlet of the turbine of the turbocharger, and the guide gate rotates around the hinge in the inlet passage of the turbine.

Preferably, the air injection mechanism includes an air supply plate disposed between an outlet of the exhaust manifold and an inlet passage of a turbine of the turbocharger, the air supply plate having a hinge groove provided thereon, and a hinge of the guide door being disposed in the hinge groove.

Preferably, the air injection mechanism comprises a joint, an air outlet pipe or a nozzle, and the joint, the air outlet pipe or the nozzle is positioned at the joint of the outlet of the exhaust manifold and the inlet of the turbine of the turbocharger.

Preferably, the two guide doors in the two inlet passages of the turbine may be rotated separately or simultaneously in conjunction.

As mentioned above, the method and the system for increasing the exhaust pressure of the engine have the following beneficial effects: the piston cylinder mechanism is not needed, but the air injection mechanism drives the guide door, so that the direction and the flow speed of the exhaust airflow are changed, the running speed of the turbocharger is improved, and the exhaust pressure of the engine is increased.

Drawings

FIG. 1 is a schematic diagram of the general construction of the system for increasing engine exhaust pressure of the present invention.

Fig. 2 is a partial cross-sectional view of the system for increasing engine exhaust pressure of the present invention, illustrating the state of the pilot door in a non-rotated initial position (non-actuated).

Fig. 3 is a partial sectional view of the system for increasing engine exhaust pressure of the present invention, illustrating the state after the pilot door is rotated (driven).

FIG. 4 is a schematic illustration of a turbine inlet passage and pilot valve position for the system for increasing engine exhaust pressure of the present invention.

FIG. 5 is a schematic illustration of an intake plate of the system for increasing engine exhaust pressure of the present invention.

Description of the element reference numerals

12 air intake manifold

13 air inlet shunting node

14 total intake pipe

210 turbocharger

222 axle

218, 228 compressor, turbine

240 tail pipe

22 exhaust manifold

23 exhaust manifold junction

24 exhaust channel

25 joint (joint end face)

26 exhaust flow passage inner wall

27 flow area of exhaust flow passage

28 turbine inlet passage

29 turbine blade

30 engines

33 piston of engine

35 Engine cylinder

40 air injection mechanism

41 air compressor

43 airway tube

45 control valve

47 air outlet pipe

48 nozzle

49 compressed air

51 nut

53 air supply joint

60 guide door

61, 63 to the inner and outer side of the door

62 guide door hinge

71 shim one

Air supply hole/slot on first 72 gaskets

74 air supply plate

75 air supply holes/grooves in air supply plate

76 hinge slot on air supply plate

77 vent/groove on gas supply plate

78 shim two

Air supply hole/groove on the second 79 spacer

100 engine brake

120 intercooler

140. 400 air

200 inlet valve

300 exhaust valve

500 engine fuel injector

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention.

Please refer to fig. 1-5. It should be noted that the drawings provided in the present embodiment are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.

FIG. 1 is a schematic diagram of the general construction of the system for increasing engine exhaust pressure of the present invention. A typical engine has a plurality of cylinders, such as a diesel engine with six cylinders in series on a commercial vehicle. For simplicity, however, only one cylinder 35 of the engine 30 is shown in FIG. 1. The piston 33 makes a reciprocating cyclic motion up and down in the cylinder 35. The four-stroke engine 30 includes in each cycle an intake stroke, a compression stroke, an expansion (or working) stroke and an exhaust stroke as is well known. During the intake stroke, piston 33 moves from top dead center to intake bottom dead center within cylinder 35 and intake valve 200 of the engine opens to introduce air into cylinder 35 of the engine. The next compression stroke is, the piston 33 moves from the intake bottom dead center to the compression top dead center, the intake valve 200 and the exhaust valve 300 of the engine are both in the closed state, the air in the cylinder 35 is compressed, when the piston 33 reaches the vicinity of the compression top dead center, the fuel oil (such as diesel oil) is injected into the cylinder through the fuel injector 500 to be mixed with the compressed air, compression ignition is carried out, and combustion is continued in the next expansion (or working) stroke, so that gas expansion is generated, and the piston 33 is driven to work from the compression top dead center to the expansion bottom dead center. Finally, in the exhaust stroke of the engine 30, the piston 33 moves from the expansion bottom dead center to the exhaust top dead center, the exhaust valve 300 of the engine opens, and the burned gas is discharged from the cylinder 35 to the exhaust manifold 22. And returning to the air inlet stroke after the exhaust stroke is finished, starting a new period, and repeating the steps in a reciprocating mode.

Most existing engines are equipped with a turbocharger 210 as shown in fig. 1 to improve the power and efficiency of the engine. The turbocharger 210 in this embodiment includes a turbine 228 and a compressor 218 connected by a shaft 222, and the exhaust manifold 22 from each cylinder 35 of the engine is connected at a junction 23 to an exhaust runner (exhaust pipe) 24, the exhaust runner 24 leading from the exhaust manifold downstream to the turbine blades 29 in the turbine 228 (see fig. 2). The exhaust gas (air during braking) from the cylinders 35 is ported from the exhaust manifold 22 at the junction 23 to the exhaust runner 24 to form an exhaust gas flow, which drives the turbine 228, which rotates with the compressor 218, which is coaxial 222, to compress the air 140 entering from the engine intake inlet passage, increasing the intake pressure in the inlet manifold 14. The total intake pipe 14 is divided into a plurality of intake manifolds 12 as required by an intake branching node 13, and each intake manifold 12 is connected to an intake valve 200 of a cylinder 35. As the temperature of the compressed air increases, reducing the efficiency of the engine, the compressed air is cooled by intercooler 120 before entering engine cylinder 35, and then split by intake split node 13 and enters cylinder 35 via intake manifold 12 and intake valve 200. Furthermore, existing engines typically have four valves per cylinder, two intake valves and two exhaust valves, with a single intake valve 200 and a single exhaust valve 300 shown in FIG. 1 for illustrative purposes only.

In fig. 1, an engine brake 100 is provided symbolically above the exhaust valve 300 for opening the exhaust valve 300 of the engine in the vicinity of the compression top dead center of the engine 30, and the gas compressed in the cylinder 35 during the compression stroke of the engine is released into the exhaust manifold 22, forming an exhaust gas flow into the exhaust channel 24 at the junction 23 of the exhaust manifold. The engine brake 100 in this embodiment may be a compression-release, bleeder, or other type of engine brake. The exhaust runner 24 in this embodiment leads to turbine blades 29 through a junction 25 of the outlet of the exhaust manifold and the inlet of the turbine of the turbocharger (25 is also denoted as the outlet end face of the exhaust manifold 22 and the inlet end face of the turbine 228, see fig. 2-4). The exhaust gas flow exits tail pipe 240 (FIG. 1) after driving turbine blades 29.

As is evident from fig. 2-5, the pilot gate 60 of the system for increasing engine exhaust pressure of the present invention is rotatably disposed within the exhaust flow passage 24 (note that the inlet passage 28 of the turbine 228 is part of the exhaust flow passage). When the guide gate 60 is at the initial position of no rotation (the rotation angle is zero), the inner side surface 61 of the guide gate 60 faces the inner wall 26 of the exhaust flow path. The rotation of the guide door 60 illustrated here is obtained by means of a hinge 62. The guide door hinge 62 is seated in a hinge slot 76 of the air supply plate 74 (see fig. 5). The two directing gates 60 in the two inlet passages 28 of the turbine may rotate independently of each other or together and simultaneously (fig. 4).

The system for increasing the exhaust pressure of the engine further comprises an air injection mechanism 40 which comprises an air compressor 41, an air guide pipe 43 and an air outlet pipe 47, wherein a control valve 45 is arranged between the air guide pipe 43 and the air outlet pipe 47, a nozzle 48 or a connector 53 (the nozzle can also be arranged in the connector) can be arranged at the end part of the air outlet pipe, and the air outlet pipe 47 is fastened on the connector 53 by a nut 51. The air compressor 41 compresses the air 400, and the compressed air is guided to the nozzle 48 through the air duct 43, the control valve 45, and the air outlet pipe 47. Of course, the compressed air may also come from an air reservoir (which is typically provided on vehicles). The invention can control the injection time and flow of air through the control valve 45 according to the available amount of vehicle-mounted compressed air, the demand of braking power, the limitation of braking load and the like. Additionally, the air injection mechanism 40 may include a one-way valve mechanism that allows compressed air to be injected from the air injection mechanism, but prevents the flow of exhaust air in the exhaust channel 24 from entering the air injection mechanism.

The working process of the invention is as follows. When the engine needs to increase the exhaust pressure of the engine, the control valve 45 is opened, the outlet pipe 47 sprays compressed air from the outside of the exhaust flow passage to the inner side surface 61 of the guide door 60 located in the exhaust flow passage through the air supply joint 53, the air supply hole/groove 72 on the first gasket 71, the air supply hole/groove 75 on the air supply plate 74 and the air supply hole/groove 79 on the second gasket 78 (see fig. 3), the guide door 60 is driven to rotate, the included angle between the guide door 60 and the inner wall 26 of the exhaust flow passage is increased, the flow direction of the exhaust flow of the engine in the exhaust flow passage is changed, the flow area 27 of the exhaust flow passage 24 is reduced, and the exhaust pressure in the exhaust flow passage 24 upstream of the guide door 60. Meanwhile, as the rotation speed of the turbocharger 210 is increased, the intake pressure and the intake airflow of the engine are also increased, and the braking power of the engine is more effectively improved.

As the angle between the guide gate 60 and the exhaust flow path inner wall 26 increases, the outer side 63 of the guide gate receives the impact of the exhaust flow. The force of the compressed air on the inner surface 61 and the force of the exhaust air flow on the outer surface 63 balance each other, and determine the angle of the guide door 60 and the flow area 27 of the exhaust flow path 24. The invention can adjust the injection time and flow of the compressed air through the control valve 45 according to different engine working conditions (such as rotating speed), and control the rotation angle of the guide gate 60 and the flow area 27 of the exhaust runner 24, thereby realizing the adjustment of the rotating speed of the turbine and the air inlet and exhaust pressure of the engine and improving the braking performance of the engine. It is apparent that the present invention not only does not affect but also improves turbocharger 210 operation, reduces turbo lag, increases intake pressure and flow and the consequent cooling effect, without increasing exhaust gas temperature and injector temperature.

In addition, since the pressures applied to the inner and

outer sides

61, 63 of the guide door 60 tend to be balanced, the thickness of the guide door 60 can be small, such as 0.5-1.5 mm, preferably 1.0 mm. In this way, the entire guide gate is not only light and takes up little space, but can be easily positioned upstream of the turbine.

The above description contains many specifics, which should not be construed as limitations on the scope of the invention, but rather as a exemplification of some of the specifics thereof, from which many other variations are possible. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention. For example, the methods herein for increasing engine exhaust pressure may be used with different engines, including overhead cam engines and pushrod engines; the valve can be used for a single-valve engine and can also be used for a multi-valve engine with more than two valves; the method can be used for braking operation of the engine and also can be used for ignition operation of the engine, such as reducing turbine delay, increasing exhaust gas recirculation and the like.

Also, the air injection mechanism herein may vary in composition, shape, installation, regulation, etc. For example, the nozzle at the end of the outlet pipe may be flat, circular truncated cone, circular hole, ring, or the like.

Furthermore, the nozzle or fitting at the end of the outlet tube can be placed in different ways at different locations.

Also, the timing, flow rate and direction of the compressed air injected by the air injection mechanism may be adjusted according to engine operating requirements, such as braking power requirements, braking load limitations and the source of the compressed air.

In addition, the inner side surface of the guide door can take different shapes, and besides a plane, the inner side surface of the guide door can also be a folding surface (combination of two or more planes), a concave surface, a combined surface or other curved surfaces. The location and manner of installation of the guide doors may also vary.

Also, the cross section of the exhaust flow path may be other than square or circular.

Claims

1. A method for increasing the exhaust pressure of engine features that an air jet mechanism is used to jet compressed air from outside the exhaust channel to a rotary guide gate in the exhaust channel, which can change the flowing direction and speed of the exhaust airflow in the exhaust channel, decrease the flow area of exhaust channel and increase the exhaust pressure in the exhaust channel.

2. The method of increasing engine exhaust pressure according to claim 1, wherein: the exhaust runner includes an inlet passage of a turbine of the turbocharger, the guide gate is located in the inlet passage of the turbine of the turbocharger, a hinge of the guide gate is disposed at a junction of an outlet of the exhaust manifold and an inlet of the turbine of the turbocharger, the guide gate is rotatable around the hinge in the inlet passage of the turbine, an inner side surface of the guide gate faces an inner wall of the exhaust runner when the guide gate is in a non-rotational initial position, and the compressed air is sprayed on the inner side surface of the guide gate.

3. The method of increasing engine exhaust pressure according to claim 2, wherein: the air injection mechanism injects compressed air to the inner side surface of the guide door in the exhaust runner at a position where the outlet of the exhaust manifold is connected to the inlet of the turbine of the turbocharger.

4. The method of increasing engine exhaust pressure according to claim 1, wherein: the turbine of the turbocharger is provided with two inlet passages, and a guide door is arranged in each inlet passage of the turbine.

5. The method of increasing engine exhaust pressure according to claim 4, wherein: the two guide doors in the two inlet passages of the turbine can rotate independently or simultaneously and together.

6. The method of increasing engine exhaust pressure according to claim 1, wherein: the air injection mechanism comprises a power source and a control valve, the power source comprises an air compressor or an air storage tank, the air compressor or the air storage tank generates the compressed air, and the control valve controls the injection time and the flow of the compressed air.

7. A system for increasing exhaust pressure from an engine having a turbocharger, an exhaust flow path between an exhaust manifold of the engine and a turbine of the turbocharger, the system comprising: the system for increasing the exhaust pressure of the engine comprises a guide door and an air injection mechanism, the guide door is arranged in the exhaust runner in a rotary mode, when the guide door is at a non-rotating initial position, the inner side surface of the guide door faces the inner wall of the exhaust runner, the air injection mechanism injects compressed air from the outer side of the exhaust runner to the inner side surface of the guide door positioned in the exhaust runner, the guide door is driven to rotate, the guide door is increased, the included angle between the inner wall of the exhaust runner is increased, the flow area of the exhaust runner is reduced, and the exhaust pressure in the upstream exhaust runner of the guide door is increased.

8. The system for increasing engine exhaust pressure according to claim 7, wherein: the inner side surface of the guide door is a plane, a folded surface or a concave surface.

9. The system for increasing engine exhaust pressure according to claim 7, wherein: the exhaust runner comprises an inlet channel of a turbine of the turbocharger, the guide door is positioned in the inlet channel of the turbine, a hinge of the guide door is arranged at the joint of an outlet of the exhaust manifold and an inlet of the turbine of the turbocharger, and the guide door rotates in the inlet channel of the turbine around the hinge.

10. The system for increasing engine exhaust pressure according to claim 7, wherein: the air injection mechanism comprises an air supply plate arranged between an outlet of the exhaust manifold and an inlet channel of a turbine of the turbocharger, a hinge groove is formed in the air supply plate, and a hinge of the guide door is arranged in the hinge groove.

11. The system for increasing engine exhaust pressure according to claim 7, wherein: the air injection mechanism comprises a power source and a control valve, the power source comprises an air compressor or an air storage tank, the air compressor or the air storage tank generates the compressed air, and the control valve controls the injection time and the flow of the compressed air.

12. The system for increasing engine exhaust pressure according to claim 7, wherein: the air injection mechanism comprises a joint, an air outlet pipe or a nozzle, and the joint, the air outlet pipe or the nozzle is positioned at the joint of the outlet of the exhaust manifold and the inlet of the turbine of the turbocharger.

13. The system for increasing engine exhaust pressure according to claim 7, wherein: the turbine of the turbocharger is provided with two inlet passages, and a guide door is arranged in each inlet passage of the turbine.

14. The system for increasing engine exhaust pressure according to claim 13, wherein: the two guide doors in the two inlet passages of the turbine can rotate independently or simultaneously and together.