CN210317447U

CN210317447U - Exhaust device and vehicle

Info

Publication number: CN210317447U
Application number: CN201920890295.2U
Authority: CN
Inventors: 王威; 隆永波; 徐辉
Original assignee: Segway Technology Co Ltd
Current assignee: Segway Technology Co Ltd
Priority date: 2019-06-13
Filing date: 2019-06-13
Publication date: 2020-04-14
Anticipated expiration: 2029-06-13
Also published as: WO2020248568A1

Abstract

The utility model discloses an exhaust apparatus and vehicle, exhaust apparatus includes: a stack of exhaust tubes having an inlet end and an outlet end, the outlet end of the stack of exhaust tubes configured with a primary expansion chamber; a muffler connected to an outlet end of the exhaust pipe group and configured with a secondary expansion chamber. According to the utility model discloses exhaust apparatus does benefit to the gaseous cooling in the blast pipe to improve the performance and the noise reduction effect of silencer.

Description

Exhaust device and vehicle

Technical Field

The utility model relates to an exhaust technical field particularly, relates to an exhaust apparatus and have exhaust apparatus's vehicle.

Background

In a related art vehicle, an exhaust pipe is connected to an exhaust port of an engine, and a muffler is generally connected to the exhaust pipe to reduce exhaust noise. For some vehicle types, due to the limitation of the whole design factor, the exhaust port of the engine is close to the muffler, so that the exhaust pipe is short, the temperature drop of high-temperature gas exhausted from the exhaust port of the engine in the exhaust pipe is limited, and the performance of the muffler is greatly influenced.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, an object of the utility model is to provide an exhaust apparatus, this exhaust apparatus does benefit to the gaseous cooling in the blast pipe to improve the performance and the noise reduction effect of silencer.

The utility model discloses still provide one kind and have exhaust apparatus's vehicle.

According to the utility model discloses an embodiment of first aspect provides an exhaust apparatus, exhaust apparatus includes: a stack of exhaust tubes having an inlet end and an outlet end, the outlet end of the stack of exhaust tubes configured with a primary expansion chamber; a muffler connected to an outlet end of the exhaust pipe group and configured with a secondary expansion chamber.

According to the utility model discloses exhaust apparatus sets up the one-level expansion chamber through the exit end at the exhaust pipe group to set up the second grade expansion chamber at the silencer, can make the high-temperature gas cooling in the exhaust pipe group like this, thereby promote the noise reduction effect and the performance of silencer.

According to some embodiments of the invention, the exhaust pipe group is internally provided with an exhaust passage, the exhaust passage is communicated with the one-stage expansion cavity, and the minimum cross-sectional area of the one-stage expansion cavity is larger than the maximum cross-sectional area of the exhaust passage.

According to some embodiments of the present invention, the exhaust pipe group is internally configured with an exhaust passage, the exhaust passage is communicated with the first-stage expansion cavity, and an axial direction of the first-stage expansion cavity is perpendicular to an axial direction of the exhaust passage.

According to some specific examples of the utility model, exhaust apparatus still includes: and the outlet end of the exhaust pipe group is connected with the muffler through the purification device.

Further, the purification device is a three-way catalyst.

Further, the exhaust apparatus further includes: and the reinforcing plate is respectively connected with the exhaust pipe group and the muffler and positioned on the outer side of the three-way catalyst.

According to some embodiments of the invention, the exhaust pipe group comprises: a first exhaust pipe having a first docking portion configured with a first docking groove; a second exhaust pipe having a second docking portion configured with a second docking slot; the adapter part is matched with the first butt joint groove and the second butt joint groove so as to enable the first exhaust pipe and the second exhaust pipe to be in butt joint; the inlet end is arranged on the first exhaust pipe, and the outlet end and the primary expansion cavity are arranged on the second exhaust pipe.

Further, the adapter part is a spherical sleeve and is clamped between the first butt joint groove and the second butt joint groove, and the first butt joint groove and the second butt joint groove are both matched with the adapter part in shape; the first butt joint part and the second butt joint part are both adjustably arranged relative to the position of the adapter part.

Further, the switching portion is a flexible piece, the switching portion is provided with a central through hole, and at least one of the first exhaust pipe and the second exhaust pipe penetrates through the central through hole.

According to some specific examples of the utility model, first blast pipe with flexible connection between the second blast pipe.

Further, the first butt joint portion of the first exhaust pipe and the second butt joint portion of the second exhaust pipe are connected through a fastener, an elastic piece is sleeved on the fastener, and the elastic piece is compressed between the fastener and the first butt joint portion and/or between the fastener and the second butt joint portion.

Further, the fastener includes a bolt and a nut fitted thereon, the bolt having a nut and a retaining step, the nut and the retaining step sandwiching one of the first abutting portion and the second abutting portion, the elastic member being compressed between the nut and the other of the first abutting portion and the second abutting portion.

According to some embodiments of the invention, the muffler is adapted for flexible connection with a vehicle frame.

Further, the silencer is provided with a rocker arm support, the rocker arm support is provided with a switching rocker arm, one end of the switching rocker arm is connected with the switching rocker arm in a pivoting mode, and the other end of the switching rocker arm is connected with a frame mounting frame suitable for being mounted on the frame in a pivoting mode.

Furthermore, the silencer is provided with a hook mounting sleeve, the hook mounting sleeve is provided with a hook with one end pivotally matched with the hook, and the other end of the hook is pivotally connected with a frame mounting sleeve suitable for being mounted on a frame.

According to the utility model discloses an embodiment of second aspect provides a vehicle, the vehicle includes: an engine; according to an embodiment of the first aspect of the present invention, the inlet end of the exhaust pipe group is connected to the engine.

According to the utility model discloses vehicle, through utilizing according to the utility model discloses an embodiment of first aspect exhaust apparatus, have advantages such as exhaust noise is little.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic structural diagram of an exhaust device according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of another view angle of an exhaust device according to an embodiment of the present invention.

Fig. 3 is a partial cross-sectional view of an exhaust apparatus according to an embodiment of the present invention.

Reference numerals:

an exhaust device 1,

A stack of exhaust tubes 100, an inlet end 110, an outlet end 120, a primary expansion chamber 130, an exhaust passage 135,

A first exhaust pipe 140, a first butt portion 141, a first hood 142,

A second exhaust pipe 150, a second butt joint portion 151, a second shield 152,

An adapter part 160,

A fastener 170, a bolt 171, a nut 172, a nut 173, a limit step 174, an elastic member 180,

A muffler 200, a secondary expansion chamber 210,

A rocker arm bracket 220, a switching rocker arm 230, a frame mounting frame 240,

A hook mounting sleeve 250, a hook 260, a frame mounting sleeve 270,

A purification device 300,

A reinforcing plate 400,

An oxygen sensor 500,

A sealing sleeve 600,

A cylinder head bolt 700,

The axial direction K of the primary expansion chamber 130 and the axial direction L of the exhaust passage.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "inner", "outer", "axial", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are merely for convenience of description and simplified description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. In addition, in the description of the present invention, "the first feature" and "the second feature" may include one or more of the features.

A vehicle according to an embodiment of the present invention is described below.

The vehicle according to the embodiment of the present invention includes an engine and an exhaust apparatus 1.

An exhaust apparatus 1 according to an embodiment of the present invention is described first with reference to the drawings.

As shown in fig. 1 to 3, an exhaust apparatus 1 according to an embodiment of the present invention includes an exhaust pipe group 100 and a muffler 200.

The exhaust stack 100 has an inlet end 110 and an outlet end 120, the inlet end 110 of the exhaust stack 100 is connected to the engine, for example, the inlet end 110 of the exhaust stack 100 is provided with a cylinder head bolt 700 and a sealing sleeve 600, the sealing sleeve 600 may be a copper sleeve, and the inlet end 110 of the exhaust stack 100 is connected to the engine through the sealing sleeve 600 and the cylinder head bolt 700. The outlet end of the stack 100 is configured with a primary expansion chamber 130. The muffler 200 is connected to the outlet end 120 of the exhaust pipe group 100, and the muffler 200 is configured with a secondary expansion chamber 210. The gas exhausted from the engine enters the exhaust pipe group 100 from the inlet end 110 of the exhaust pipe group 100, passes through the primary expansion chamber 130, and enters the secondary expansion chamber 210 of the muffler 200 from the outlet end 120. It will be understood by those skilled in the art that the term "primary expansion chamber 130" refers to a chamber structure configured at the outlet end 120 of the stack 100 to expand and decompress the gas flowing therethrough, thereby reducing the temperature thereof.

According to the utility model discloses exhaust apparatus 1, exit end 120 through at exhaust pipe group 100 sets up one-level expansion chamber 130, and set up second grade expansion chamber 210 at silencer 200, like this engine exhaust's high-temperature gas gets into one-level expansion chamber 130 in exhaust pipe group 100 when, the flow cross-sectional area increases suddenly, high-temperature gas expands rapidly, the decompression, thereby the temperature reduces, the air current after the cooling gets into the second grade expansion chamber 210 of silencer 200, handle the back through second grade expansion chamber 210, can promote silencer 200's noise reduction effect and performance, therefore, even the gas vent and the silencer of engine are at a distance from nearer, also can guarantee the better performance of silencer 200 performance.

Therefore, according to the utility model discloses exhaust apparatus 1 does benefit to the gaseous cooling in the blast pipe to improve the performance and the noise reduction effect of silencer.

According to the utility model discloses vehicle, through utilizing according to the utility model discloses exhaust apparatus 1 of above-mentioned embodiment has advantages such as exhaust noise is little.

It will be appreciated by those skilled in the art that the exhaust apparatus 1 according to the embodiment of the present invention is not limited to the application to vehicles, and may be applied to any other applicable fields.

In some embodiments of the present invention, as shown in fig. 1 to 3, the exhaust duct 135 is configured in the exhaust duct group 100, and the exhaust duct 135 is communicated with the first-stage expansion cavity 130, i.e. it can be understood that the inner space of the exhaust duct group 100 is substantially divided into the exhaust duct 135 and the first-stage expansion cavity 130, and the minimum cross-sectional area of the first-stage expansion cavity 130 is larger than the maximum cross-sectional area of the exhaust duct 135, so that the high-temperature gas in the exhaust duct 135 can be rapidly expanded and cooled after entering the first-stage expansion cavity 130.

Further, as shown in fig. 1, the axial direction K of the first-stage expansion chamber 130 is perpendicular to the axial direction L of the exhaust passage 135, so that the high-temperature gas in the exhaust passage 135 needs to be diverted and then enters the first-stage expansion chamber 130, thereby reducing the flow rate of the high-temperature gas to further reduce the temperature.

In some specific examples of the present invention, as shown in fig. 1, the exhaust device 1 further includes a purification device 300 for purifying gas exhausted from the engine, for example, the purification device 300 is a three-way catalyst, the outlet end 120 of the exhaust pipe set 100 is connected to the muffler 200 through the purification device 300, and the gas after cooling and speed reduction can reduce the impact on the purification device 300.

In the present embodiment, the exhaust pipe group 100 is provided with an oxygen sensor 500 for detecting the concentration of oxygen in exhaust gas, and sends a feedback signal to an ECU (electronic control unit), and the ECU controls the increase and decrease of the fuel injection amount of the injector, thereby controlling the air-fuel ratio of the mixture to be near the theoretical value.

Further, as shown in fig. 1, the exhaust device 1 further includes a reinforcing plate 400, the reinforcing plate 400 is connected to the exhaust pipe group 100 and the muffler 200, respectively, and the reinforcing plate 400 is located outside the three-way catalyst (i.e., the purification device 300), for example, the reinforcing plate 400 may be plural and spaced around the outside of the three-way catalyst. This enhances the stability of the relative positions of the exhaust pipe group 100 and the muffler 200, and improves the overall structural strength of the exhaust device 1.

In some embodiments of the present invention, as shown in fig. 1-3, the exhaust stack 100 includes a first exhaust pipe 140, a second exhaust pipe 150, and an adapter 160.

The first exhaust pipe 140 has a first butting portion 141 and the first butting portion 141 is configured with a first butting groove. The second exhaust pipe 150 has a second docking portion 151 and the second docking portion 151 is configured with a second docking groove. The adapter 160 is fitted to the first and second docking slots to dock the first and

second exhaust pipes

140 and 150. Wherein the inlet end 110 is disposed in the first exhaust pipe 140, and the outlet end 120 and the primary expansion chamber 130 are disposed in the second exhaust pipe 150.

Accordingly, by constructing the first docking portion 141 in the first exhaust pipe 140 and the second docking portion 151 in the second exhaust pipe 150 and providing the adapter 160 between the first docking groove of the first docking portion 141 and the second docking groove of the second docking portion 151, the contact area between the first docking portion 141 and the adapter 160 and the contact area between the second docking portion 151 and the adapter 160 can be made large, so that the gas in the first exhaust pipe 140 does not leak from the gap between the first exhaust pipe 140 and the adapter 160, and the gas in the second exhaust pipe 150 does not leak from the gap between the second exhaust pipe 150 and the adapter 160.

Moreover, in view of the influence of the permanent errors and deformation in the manufacturing process on the joint between the front and rear exhaust pipes (the first exhaust pipe 140 and the second exhaust pipe 150) of the muffler, after the muffler 200 is assembled according to the specified assembly process, the joint between the first exhaust pipe 140 and the second exhaust pipe 150 has sufficient freedom, so that the abnormality of improper assembly or air leakage does not occur, and when the muffler is reliably supported, no additional assembly adjustment operation is required, i.e., the leakage risk caused by the machining error, welding deformation, assembly error and the like is greatly reduced.

As shown in fig. 2, in order to protect the first exhaust pipe 140 and the second exhaust pipe 150, the first shield 142 may be covered on the outer side of the first exhaust pipe 140, and the second shield 152 may be covered on the outer side of the second exhaust pipe 150.

In some embodiments of the present invention, as shown in fig. 3, the adapter 160 is a spherical sleeve and is sandwiched between the first butt-joint groove and the second butt-joint groove, the first butt-joint groove and the second butt-joint groove are disposed oppositely, and the first butt-joint groove and the second butt-joint groove are both adapted to the shape of the adapter 160. The first docking portion 141 and the second docking portion 151 are adjustably arranged relative to the docking portion 160, so that the docking portion 160 can rotate in different directions between the first docking portion 141 and the second docking portion 151, that is, enough freedom is guaranteed, and the first exhaust pipe 140 and the second exhaust pipe 150 can be movably connected.

As will be understood by those skilled in the art, the term "spherical sleeve" is understood to mean that a through hole is formed in a sphere for connection or ventilation, so as to ensure that the first exhaust pipe 140 and the second exhaust pipe 150 are communicated with each other.

Further, the adaptor 160 is a flexible member, such as a rubber member, a silicone member, or a graphite member, and the adaptor 160 has a central through hole through which at least one of the first exhaust pipe 140 and the second exhaust pipe 150 passes. Therefore, the adaptor 160 is a deformable spherical sleeve, which further improves the sealing performance between the first adaptor 141 and the adaptor 160 and between the second adaptor 151 and the adaptor 160, and at the same time, in order to prevent the adaptor 30 from generating large deformation, at least one of the first exhaust pipe 140 and the second exhaust pipe 150 is inserted into the central through hole of the adaptor 160, which can support the adaptor 160.

Alternatively, as shown in fig. 3, the first docking portion 141 is disposed in the middle of the first exhaust pipe 140, and the second docking portion 151 is disposed at the end of the second exhaust pipe 150, that is, the first exhaust pipe 140 is inserted into the central through hole of the docking portion 160 to support the docking portion 160.

In some embodiments of the present invention, it is considered that the first exhaust pipe 140 and the second exhaust pipe 150 will shake in the specific use process, and therefore, the first exhaust pipe 140 and the second exhaust pipe 150 are flexibly connected to each other, so that the first exhaust pipe 140 and the second exhaust pipe 150 can be adjusted in position relative to the adapter 160, and thus, when the first exhaust pipe 140 and the second exhaust pipe 150 shake, an obvious buffering effect is provided between the first exhaust pipe 140 and the second exhaust pipe 150.

Specifically, as shown in fig. 3, the first docking portion 141 of the first exhaust pipe 140 and the second docking portion 151 of the second exhaust pipe 150 are connected by a fastening member 170, an elastic member 180, such as a spring, is sleeved on the fastening member 170, and the elastic member 180 is compressed between the fastening member 170 and the first docking portion 141 and/or between the fastening member 170 and the second docking portion 151. Thus, the first docking portion 141 and the second docking portion 151 are connected by the fastener 170, while the flexible connection between the first exhaust pipe 140 and the second exhaust pipe 150 is ensured by the elastic member 180, and the elastic force of the elastic member 180 presses the first docking portion 141 and the second docking portion 151 toward each other, so that the first docking portion 141 and the second docking portion 151 press the adaptor 160.

Wherein, the fastening member 170 and the elastic member 180 may be provided in multiple sets, each set includes one fastening member 170 and at least one elastic member 180, and the multiple sets are spaced apart from each other along the circumferential direction of the first exhaust pipe 140.

In some specific examples of the present invention, as shown in fig. 3, the fastener 170 includes a bolt 171 and a nut 172 fitted on the bolt 171. The bolt 171 has a nut 173 and a retaining step 174, the nut 172 and the retaining step 174 clamp one of the first and

second butting portions

141 and 151, and the elastic member 180 is compressed between the other of the first and

second butting portions

141 and 151 and the nut 173. In fig. 3, the nut 172 and the stopping step 174 clamp the second butting portion 151, and the elastic member 180 is compressed between the first butting portion 141 and the nut 173.

In some embodiments of the present invention, the muffler 200 is adapted to be flexibly coupled to a vehicle frame.

Specifically, as shown in fig. 1 and 2, the muffler 200 is provided with a rocker arm bracket 220, the rocker arm bracket 220 may be disposed at the top of the muffler 200, the rocker arm bracket 220 is provided with a transfer rocker arm 230 having one end pivotably connected thereto, and the other end of the transfer rocker arm 230 is pivotably connected to a frame mounting bracket 240 adapted to be mounted to the vehicle frame. The switching rocker arm 230 and the rocker arm bracket 220 and the switching rocker arm 230 and the frame mounting bracket 240 can be respectively connected by bolts, the rotation axes of the two ends of the rocker arm bracket 220 are parallel to each other, and the rotation axes of the two ends of the rocker arm bracket 220 are perpendicular to the axial direction of the secondary expansion cavity 210 of the muffler 200. Thus, the muffler 200 can be adjusted in position relative to the vehicle body frame by the switching rocker arm 230, and a rigid collision does not occur between the muffler 200 and the vehicle body frame even if the muffler 200 shakes.

Further, as shown in fig. 1, the muffler 200 is provided with a hook mounting sleeve 250, the hook mounting sleeve 250 may be disposed at the bottom of the muffler 200, the hook mounting sleeve 250 is provided with a hook 260 having one end pivotally engaged therewith, the other end of the hook 260 is pivotally connected with a frame mounting sleeve 270 adapted to be mounted with the frame, and the frame mounting sleeve 270 may be a flexible member. Wherein the hook 260 may be generally U-shaped, one end of the hook 260 is fitted into the hook mounting sleeve 250 and the other is fitted into the frame mounting sleeve 270, the rotation axes of both ends of the hook 260 are parallel to each other, and the rotation axes of both ends of the hook 260 are parallel to the axial direction of the secondary expansion chamber 210 of the muffler 200. Thus, frame mounting sleeve 270 acts as a cushion sleeve, eliminating rigid contact between hanger 260 and the frame. Wherein the frame mounting sleeve 270 is rigidly connected to the frame via a rigid structure.

Other configurations and operations of the vehicle and the exhaust apparatus 1 according to the embodiment of the present invention are known to those skilled in the art and will not be described in detail herein.

In the description herein, references to the description of the terms "particular embodiment," "particular example," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example.

While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An exhaust apparatus, comprising:

a stack of exhaust tubes having an inlet end and an outlet end, the outlet end of the stack of exhaust tubes configured with a primary expansion chamber;

a muffler connected to an outlet end of the exhaust pipe group and configured with a secondary expansion chamber.

2. The exhaust apparatus as claimed in claim 1, wherein an exhaust passage is configured in said exhaust tube bank, said exhaust passage communicating with said primary expansion chamber, a minimum cross-sectional area of said primary expansion chamber being greater than a maximum cross-sectional area of said exhaust passage.

3. The exhaust apparatus as claimed in claim 1, wherein an exhaust passage is configured in said exhaust pipe group, said exhaust passage communicating with said primary expansion chamber, an axial direction of said primary expansion chamber being perpendicular to an axial direction of said exhaust passage.

4. The exhaust apparatus of claim 1, further comprising:

and the outlet end of the exhaust pipe group is connected with the muffler through the purification device.

5. An exhaust arrangement according to claim 4, characterized in that the purification device is a three-way catalyst.

6. The exhaust apparatus of claim 5, further comprising:

and the reinforcing plate is respectively connected with the exhaust pipe group and the muffler and positioned on the outer side of the three-way catalyst.

7. The exhaust apparatus as claimed in any one of claims 1 to 6, wherein the exhaust pipe group includes:

a first exhaust pipe having a first docking portion configured with a first docking groove;

a second exhaust pipe having a second docking portion configured with a second docking slot;

the adapter part is matched with the first butt joint groove and the second butt joint groove so as to enable the first exhaust pipe and the second exhaust pipe to be in butt joint;

the inlet end is arranged on the first exhaust pipe, and the outlet end and the primary expansion cavity are arranged on the second exhaust pipe.

8. The exhaust device according to claim 7, wherein the adapter portion is a spherical sleeve and is interposed between the first docking groove and the second docking groove, and both the first docking groove and the second docking groove are adapted to the shape of the adapter portion;

the first butt joint part and the second butt joint part are both adjustably arranged relative to the position of the adapter part.

9. The exhaust device according to claim 8, wherein the adapter is a flexible member, the adapter is provided with a central through hole, and at least one of the first exhaust pipe and the second exhaust pipe is arranged in the central through hole in a penetrating manner.

10. The exhaust apparatus of claim 7, wherein the first exhaust pipe is flexibly connected to the second exhaust pipe.

11. The exhaust apparatus according to claim 10, wherein the first mating portion of the first exhaust pipe and the second mating portion of the second exhaust pipe are connected by a fastener, and an elastic member is fitted over the fastener and compressed between the fastener and the first mating portion and/or between the fastener and the second mating portion.

12. The exhaust apparatus according to claim 11, wherein the fastener includes a bolt and a nut fitted thereon, the bolt having a nut and a retaining step, the nut and the retaining step sandwiching one of the first and second abutments, the elastic member being compressed between the nut and the other of the first and second abutments.

13. An exhaust arrangement according to any of claims 1 to 6, wherein the muffler is adapted for flexible connection to a vehicle frame.

14. An exhaust arrangement according to claim 13, wherein the muffler is provided with a rocker arm support having an adaptor rocker arm pivotally connected at one end thereof, the other end of the adaptor rocker arm being pivotally connected to a frame mounting bracket adapted for mounting to the vehicle frame.

15. The exhaust apparatus as claimed in claim 13, wherein said muffler is provided with a hanger mounting sleeve having one end pivotally engaged therewith, and the other end of said hanger being pivotally connected to a frame mounting sleeve adapted to be mounted to said frame.

16. A vehicle, characterized by comprising:

an engine;

an exhaust device according to any one of claims 1 to 15, the inlet end of the stack being connected to the engine.