WO2019110131A1

WO2019110131A1 - Exhaust sampling tube

Info

Publication number: WO2019110131A1
Application number: PCT/EP2017/082102
Authority: WO
Inventors: James OLDEN; Rohan RAVINDRAN
Original assignee: Toyota Motor Europe NV SA
Current assignee: Toyota Motor Europe NV SA
Priority date: 2017-12-08
Filing date: 2017-12-08
Publication date: 2019-06-13
Anticipated expiration: 2020-06-08

Abstract

The present invention concerns to automobile emissions testing and more specifically to an exhaust sampling tube (22) for sampling combustion gases flowing out of an exhaust pipe (18) of an automobile (1). The exhaust sampling tube (22) extends from a first end (222) for coupling to the exhaust pipe (18) to a second end (223) which is open, and comprises at least one exhaust sampling port (224), located between the first and second ends (222), (223), for fluid connection to an exhaust analyzer (23), and a mechanical coupler (30) for suspending the exhaust sampling tube (22) from a support structure (21).

Description

EXHAUST SAMPLING TUBE

TECHNICAL FIELD

The disclosure relates to automobile emissions testing and more specifically to an exhaust sampling tube for sampling combustion gases flowing out of an automobile exhaust pipe. Within the present disclosure, the term "automobile" should be understood broadly, and extends not just to passenger cars, but to any self-propelled road, off-road or railed vehicle, wheeled or tracked vehicle, including passenger cars, buses, trucks, tractors, motorcycles, trains, etc.

BACKGROUND

Automobiles, when propelled using at least a combustion engine, are typically subject to emissions testing regulations, both for type certification and periodic vehicle inspection purposes. During such emissions testing, the combustion gases exhausted by the combustion engine through an exhaust pipe of the automobile are sampled and analyzed to determine their composition. For this, an exhaust sampling tube comprising at least one exhaust sampling port in fluid connection to an exhaust analyzer is typically coupled to the exhaust pipe, so that the combustion gases flowing out of the exhaust pipe and through the exhaust sampling tube may be sampled through the at least one exhaust sampling port and analyzed with the exhaust analyzer.

Because emissions testing had, until now, usually been carried out in stationary test benches, the coupling of the exhaust sampling tube to the exhaust pipe was considered sufficient to support it. However, emissions testing regulations increasingly include requirements for real driving conditions emissions testing, that is, with the automobile no longer stationary but in motion. Under such circumstances, vibrations may shake the exhaust sampling tube so much that measurements become inaccurate and unreliable, the fluid connection of the at least one exhaust sampling port to the exhaust analyzer may be lost, and changes in the orientation of the exhaust sampling tube may lead to condensed water accumulating within the exhaust sampling tube, from where it may flow through the at least one exhaust sampling port to the exhaust analyzer, possibly damaging the latter. SUMMARY

A first object of the present disclosure is that of providing a more stable exhaust sampling tube for use in real driving conditions emissions testing.

According to a first aspect of the present disclosure, an exhaust sampling tube extending from a first end for coupling to automobile exhaust pipe of an automobile to a second end which is open may thus comprise at least one exhaust sampling port, located between the first and second ends, for fluid connection to an exhaust analyzer, and a mechanical coupler for suspending the exhaust sampling tube from a support structure.

Suspending the exhaust sampling tube from a support structure through a mechanical coupler can complement the coupling of the exhaust pipe to the automobile exhaust pipe, thus improving the stability of the exhaust sampling tube resulting in easier, more accurate, reliable emissions testing and helping reduce the risk of damage to the exhaust analyzer by condensed water.

According to a second aspect, the mechanical coupler may comprise a damper, in particular a viscoelastic damper, such as for example a damper comprising an elastomer. Such a damper incorporated in the mechanical coupler can damp vibration of the exhaust sampling tube, further improving its stability.

According to a third aspect, the mechanical coupler may comprise a first coupling point and a second coupling point, offset with respect to reach other in a longitudinal direction of the exhaust sampling tube. The two offset coupling points prevent the exhaust sampling tube from pivoting around an axis perpendicular to said longitudinal direction, thus increasing the stability of the exhaust sampling tube. Said stability may further be improved if the connection of the first end of the exhaust sampling tube to the exhaust pipe of the automobile is offset perpendicularly to said longitudinal direction with respect to said first and second coupling points, thus providing a statically stable three-point support for the exhaust sampling tube. In order to facilitate adaptation of the mechanical coupler to different support structures, a distance between the first and second coupling points in the longitudinal direction may be adjustable.

According to a fourth aspect, the exhaust sampling tube may comprise an L-bend at the first end. When the exhaust pipe to which this first end is to be coupled is a tailpipe located at a rear end of the automobile and roughly oriented in a longitudinal direction of the automobile, such an L-bend will allow the exhaust sampling tube to be oriented along the rear end of the automobile, in a relatively unobtrusive arrangement.

According to a fifth aspect, to facilitate the drainage of condensed water from the exhaust sampling tube, the exhaust sampling tube may be inclined so that the second end is located lower than the first end.

According to a sixth aspect, the exhaust sampling tube may comprise an internal pitot tube, located between the first and second ends, and a dynamic pressure sampling port for fluid connection of the internal pitot tube to a pressure sensor. Through this arrangement, it is possible to sample and measure a dynamic pressure, and thus a flowrate, of the exhaust within the exhaust sampling tube. Such a flowrate, together with the composition of the sampled combustion gases according to the exhaust analyzer, can be used for the calculation of the total emissions for each component of the sampled combustion gases measured by the exhaust analyzer.

Another object of the disclosure is that of providing a robust and reliable emissions testing device for real driving conditions emissions testing. Consequently, an emissions testing device according to a seventh aspect may comprise a support structure for attachment to an automobile, the abovementioned exhaust sampling tube, suspended by the mechanical coupler from the support structure, and an exhaust analyzer in fluid connection with the at least one exhaust sampling port. The exhaust analyzer may be supported by the support structure. Alternatively, however, it may be carried onboard the automobile.

According to an eighth aspect of the disclosure, the support structure may be adapted to be attached to a tow hitch mounted on a rear end of the automobile. Such a tow hitch can provide a particularly stable support on the automobile to the support structure and all elements carried by it, including the exhaust sampling tube.

Another object of the disclosure is that of providing an automobile with a robust and reliable emissions testing device for real driving conditions emissions testing. Consequently, an automobile according to a ninth aspect may be equipped with the abovementioned emissions testing device, wherein the support structure is attached to the automobile and the first end of the exhaust sampling tube is coupled to an exhaust pipe of the automobile. The support structure may in particular be attached to a rear end of the automobile and the exhaust pipe may be a tailpipe. In this case, the exhaust sampling tube is oriented in a transversal direction of the automobile, in a relatively unobtrusive arrangement. Yet another object of the disclosure is that of providing a method for reliably mounting the abovementioned exhaust sampling tube to an automobile. Consequently, according to a tenth aspect of the present disclosure, such a method may comprise the steps of coupling the first end of the exhaust sampling tube to an exhaust pipe of the automobile, suspending the exhaust sampling tube under a support structure using the mechanical coupler of the exhaust sampling tube, and attaching the support structure to the automobile. These steps may not necessarily be carried out in the order in which they have been enumerated.

The above summary of some aspects is not intended to describe each disclosed embodiment or every implementation of the invention. In particular, selected features of any illustrative embodiment within this specification may be incorporated into an additional embodiment unless clearly stated to the contrary.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of the following detailed description of two embodiments in connection with the accompanying drawings, in which :

- FIG. 1 is a side view of an automobile equipped with an emissions testing device including an exhaust sampling tube ;

- FIG. 2 is a rear view of the automobile and emissions testing device of FIG. 1

- FIG. 3 is a close-up view of the exhaust sampling tube of FIGS. 1 and 2 ; and

- FIG. 4 is a close-up view of an exhaust sampling tube according to an alternative embodiment.

While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit aspects of the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention.

DETAILED DESCRIPTION

For the following defined terms, these definitions shall be applied, unless a different definition is given in the claims or elsewhere in this specification. As used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term "or" is generally employed in its sense including "and/or" unless the content clearly dictates otherwise.

The following detailed description should be read with reference to the drawings in which similar elements in different drawings are numbered the same. The detailed description and the drawings, which are not necessarily to scale, depict illustrative embodiments and are not intended to limit the scope of the invention. The illustrative embodiments depicted are intended only as exemplary. Selected features of any illustrative embodiment may be incorporated into an additional embodiment unless clearly stated to the contrary.

An automobile 1 equipped with an emissions testing device 2 for emissions testing under real driving conditions, that is, on the move rather than in a static test bench, is illustrated on FIGS. 1 and 2. As shown on these drawings, the automobile 1 may comprise a drivetrain including a combustion engine 12, a transmission 13 and drive wheels 14. The combustion engine 12 may in particular be an internal combustion engine, and the drivetrain may eventually be a hybrid drivetrain also including an electric motor or motor/generator (not shown) coupled to the transmission 13. The automobile 1 may further comprise an exhaust line 15 connected to the combustion engine 12 for exhausting combustion gases therefrom. This exhaust line 15 may comprise emissions-control equipment 16, such as a catalytic converter, and a silencer 17 and end at an open end of an exhaust pipe 18, which may be configured, as shown, as a tailpipe at a rear end of the automobile, although other configurations, such as sidepipes or vertical pipes can also be considered, for instance for trucks.

In order to carry out on-the-move exhaust sampling and analysis of the combustion gases exhausted by the combustion engine 12 through this exhaust pipe 18, the automobile 1 may be equipped as shown with an emissions testing device 2 comprising a support structure 21, an exhaust sampling tube 22 and an exhaust analyzer 23. The support structure 21 may comprise means for attachment to the automobile 1, and more specifically to the rear end of the automobile 1. As shown, these attachment means may comprise a coupling device 28 for coupling the support structure 21 to a tow hitch 19 of the automobile 1, which may take the form of a tow ball as shown, or any alternative conventional form of tow hitch. To prevent the emissions testing device 2 from falling backwards upon acceleration of the automobile 1, the coupling device 22 may be complemented with upper attachment points 29 to the rear end of the automobile 1. The support structure 21 may further comprise an equipment rack 24 for receiving various units of the exhaust analyzer 23. Said exhaust analyzer 23 may comprise i.a. sensors for measuring the concentrations of various components of the combustion gas within the exhaust, such as for instance oxygen (0₂), carbon monoxide (CO), carbon dioxide (C0₂), nitrogen oxide (NO), nitrogen dioxide (N0₂), hydrocarbons (HC), as well as particulates, possibly including sensors for variously-sized particulates. To allow the calculation of total emissions values for the various components, the emissions testing device 2 may also include a flowrate sensor which may take the form, for example, of a dynamic pressure sensor in the exhaust analyzer 23, in fluid connection with a pitot tube 221 within the exhaust sampling tube 22. Through the pitot tube 221, a stagnation pressure can be sampled, from which the dynamic pressure can be calculated by deducting a static pressure which may be obtained either by sampling through a static pressure port in the exhaust sampling tube 22 or by sampling the atmospheric pressure and assuming it to be equivalent to the static pressure within the exhaust sampling tube 22. The flow speed and thus the flow rate of the combustion gases within the exhaust sampling tube 22 can then be inferred from the dynamic pressure.

The exhaust sampling tube 22 may extend from a first end 222 to a second end 223. The first end 222 may be coupled to the open end of the exhaust pipe 18 of the automobile 1, for instance using a flexible hose 26 and clamping collars 27 as shown. The second end 223 may be open, in order to exhaust the combustion gases circulating through the exhaust sampling tube 22. Between the first end 222 and the second end 223, the exhaust sampling tube 22 may comprise an L-bend, as shown, so that the longitudinal direction L of the exhaust sampling tube 22 may be oriented perpendicularly to that of the exhaust pipe 18, for example so as to substantially align this longitudinal direction L of the exhaust sampling tube 22 with a transversal direction Y of the automobile 1, as shown. Between the first and second ends 222, 223, the exhaust sampling tube 22 may also comprise sampling ports, including a dynamic pressure sampling port 224 connected to the pitot tube 221 and other exhaust sampling ports 226. These exhaust sampling ports 224 may be put in fluid connection with the exhaust analyzer 23, for example using flexible ducts as shown, for sampling and analysis of the combustion gases flowing through the exhaust sampling tube 22. The exhaust sampling tube 22 may further comprise sensors 225, such as for instance temperature and/or static pressure sensors, directly integrated within this exhaust sampling tube 22. A wired or wireless data connection between these sensors 225 and the exhaust analyzer 23 may allow the transmission of values sensed by these sensors 225 to the exhaust analyzer 23.

To hold the exhaust sampling tube 22 in a robust and stable manner, it may also comprise a mechanical coupler 30 for suspending the exhaust sampling tube 22 from the support structure 21, and more specifically under it. As shown, this mechanical coupler 30 may comprise a first coupling point 31 and a second coupling point 32, which may be mounted on respective vertical arms 33, 34, and offset with respect to each other in the longitudinal direction L of the exhaust sampling tube. The mechanical coupler may be configured, as shown, so that when the exhaust sampling tube 22 is suspended from the support structure 21, the exhaust sampling tube be inclined, with respect to the horizontal plane, by an inclination angle a (ALPHA), which may for example have a value in a range between 5 and 10°, so as to hold the second end 223 of the exhaust sampling tube 22 lower than the first end 222, and so ensure effective drainage of condensed water from within the exhaust line 15 and exhaust sampling tube 22. As shown on FIG. 1, the first and second coupling points 31, 32 may also be offset, in a longitudinal direction X of the vehicle 1 and thus perpendicularly to the longitudinal direction L of the exhaust sampling tube 22, from the coupling of the first end 222 of the exhaust sampling tube 22 to the open end of the exhaust pipe 18 of the automobile 1. In this manner, the mechanical coupler 30 together with this coupling to the exhaust pipe 18 may offer a statically stable three-point support to the exhaust sampling tube 22.

To damp vibrations of the exhaust sampling tube 22 during movement of the automobile 1, the mechanical coupler 30 may further comprise, at each coupling point 31, 32, a damper 35. These dampers 35 may in particular be viscoelastic dampers, and more specifically elastomeric dampers. As shown, they may for example take the form of elastomer blocks interposed between the support structure 21 and the upper ends of the respective vertical arms 33, 34 of the mechanical coupler 30. Bolts 36 may connect each damper 35 to the respective vertical arm 33, 34 and to the support structure 21, although alternative releasable or fixed connection means may also be considered.

Although in the embodiment illustrated in FIG. 3 the position of the coupling points 31, 32 with respect to each other and the centerline of the exhaust sampling tube 22 is fixed, they may be adjustable, as in the alternative embodiment illustrated in FIG. 4. For this purpose, at least one, and possibly both vertical arms 33, 34 may be slidable in the longitudinal direction L of the exhaust sampling tube 22, and the mechanical coupler 30 further comprise means, such as a detent mechanism, for selectively holding at least one, and possibly both vertical arms 33, 34 in various positions in the longitudinal direction L of the exhaust sampling tube 22. Moreover, at least one, and possibly both vertical arms 33, 34 may have adjustable lengths, for example with the illustrated telescopic structure, and further comprise means, such as another detent mechanism, for selectively holding an arm length among various available arm lengths. Through these various available adjustments, the exhaust sampling tube 22 may be adapted to various different support structures 21 and automobiles 1.

The emissions testing device 2, including the exhaust sampling tube 22, may be assembled and mounted to the automobile 1 according to the following method: As a first step, the exhaust analyzer 23 may be mounted onto the support structure 21, which may then be attached to the automobile 1, and in particular to the rear end of the automobile 1, using for instance the coupling device 22 and upper attachment points 29 to couple the support structure 21 to the tow hitch 19 and rear end of the automobile 1. In the next step, the exhaust sampling tube 22 may be coupled by its first end 222 to the open end of the exhaust pipe 18 of the automobile 1, for instance using the flexible hose 30 and clamping collars 31. The exhaust sampling tube 22 can then be suspended from the support structure 21 using the mechanical coupler 30, and the sampling ports 224, 226 and sensors 225 may then be connected to the exhaust analyzer 23, for example using, respectively, flexible ducts and wired or wireless data connections. Each one of these steps may however be carried out in a different order, depending mainly on the user's convenience.

Those skilled in the art will recognize that the present invention may be manifested in a variety of forms other than the specific embodiments described and contemplated herein. Accordingly, departure in form and detail may be made without departing from the scope of the present invention as described in the appended claims.

Claims

1. An exhaust sampling tube (22) extending from a first end (222) for coupling to an exhaust pipe (18) of an automobile (1) to a second end (223) which is open, and comprising:

at least one exhaust sampling port (226), located between the first and second ends (222,223), for fluid connection to an exhaust analyzer (23) ;

a mechanical coupler (30) for suspending the exhaust sampling tube (22) from a support structure (21).

2. The exhaust sampling tube (22) of claim 1, wherein the mechanical coupler (30) comprises a damper (35).

3. The exhaust sampling tube (22) of claim 2, wherein the damper (35) comprises an elastomer.

4. The exhaust sampling tube (22) of any one of claims 1 to 3, wherein the mechanical coupler (30) comprises a first coupling point (31) and a second coupling point (32), offset with respect to reach other in a longitudinal direction (L) of the exhaust sampling tube (22).

5. The exhaust sampling tube (22) of claim 4, wherein a distance between the first and second coupling points (31,32) in the longitudinal direction (L) is adjustable.

6. The exhaust sampling tube (22) of any one of claims 1 to 5, comprising an L-bend at the first end (222).

7. The exhaust sampling tube (22) of any one of claims 1 to 6, inclined so that the second end (223) is located lower than the first end (222).

8. The exhaust sampling tube (22) of any one of claims 1 to 7, comprising an internal pitot tube (221), located between the first and second ends (222, 223), and a dynamic pressure sampling port (224) for fluid connection of the internal pitot tube (221) to a pressure sensor.

9. An emissions testing device (2) comprising a support structure (21) for attachment to an automobile (1), the exhaust sampling tube (22) of any one of claims 1 to 8, suspended by the mechanical coupler (30) from the support structure (21), and an exhaust analyzer (23) in fluid connection with the at least one exhaust sampling port (226).

10. The emissions testing device (2) of claim 9, wherein the exhaust analyzer (23) is supported by the support structure (21).

11. The emissions testing device (2) of any one of claims 9 or 10, wherein the support structure (21) is adapted to be attached to a tow hitch (19) mounted on a rear end of the automobile (1).

12. An automobile (1) equipped with the emissions testing device (2) of any one of claims 9 to 11, wherein the support structure (21) is attached to the automobile (1) and the first end (222) of the exhaust sampling tube (22) is coupled to an exhaust pipe (18) of the automobile (1).

13. The automobile (1) of claim 12, wherein the support structure (21) is attached to a rear end of the automobile (1) and the exhaust pipe (18) is a tailpipe.

14. The automobile (1) of claim 13, wherein the exhaust sampling tube (22) is oriented in a transversal direction of the automobile.

15. A method for mounting the exhaust sampling tube (22) of any one of claims 1-8 to an automobile (1), comprising the steps of:

coupling the first end (222) of the exhaust sampling tube (22) to an exhaust pipe (18) of the automobile (1) ;

suspending the exhaust sampling tube (22) from a support structure (21) using the mechanical coupler (30) of the exhaust sampling tube (22) ; and

attaching the support structure (21) to the automobile (1).