JP6167056B2 - Gas sensor evaluation method - Google Patents

Description

  The present invention relates to a method for evaluating a gas sensor such as an oxygen sensor or a NOx sensor disposed in an exhaust passage of an internal combustion engine.

Conventionally, electromotive forces of different magnitudes or resistance values change depending on the concentration of a specific gas such as oxygen or NOx (nitrogen oxide) in the exhaust gas of an internal combustion engine such as an automobile or a motorcycle. A gas sensor having a detection element is known.
For example, a gas sensor shown in FIG. 1 is known. As shown in FIG. 1, the gas sensor 50 surrounds and holds a detection element 50b extending in the direction of the axis O with a metal shell 50a, and covers the detection element 50b protruding from the metal shell 50a toward the front end side with a protector 50d. It has a configuration. A male screw portion 50c for screwing the gas sensor 50 to an engine head, an exhaust pipe or the like is formed on the front end side of the metal shell. In FIG. 1, the detection element 50b is covered with a protector 50d, and can be seen from the outside only through a gas introduction hole 50e provided in the protector 50d.
By the way, such a gas sensor 50 needs to evaluate the durability of the gas sensor before actually using it (before shipment). When performing such durability evaluation, evaluation is usually performed by directly attaching a gas sensor to an exhaust passage (exhaust pipe) of an actual engine in a test chamber and exposing the gas sensor to exhaust gas discharged from an internal combustion engine ( Patent Document 1).

JP 2003-177111 A

However, for example, a gas sensor for a motorcycle has a specification that can be attached to an engine head. In this case, in an actual vehicle, the engine (engine head) is cooled by the traveling wind during traveling, and as a result, the gas sensor can be cooled. For this reason, the heat resistance of the metal fittings, which are constituent parts of the gas sensor, and the wiring parts such as the lead wires inside the gas sensor are designed to be low in consideration of cooling in actual use.
On the other hand, if the gas sensor is directly attached to the exhaust passage of the actual engine in the test chamber as described above and the durability of the gas sensor is evaluated by operating the engine for a long time, the gas sensor is It may overheat and the components of the gas sensor may melt.
A method for evaluating the durability of the gas sensor by attaching a gas sensor for evaluation to the engine head of the motorcycle and actually running the vehicle is conceivable. However, with this method, there is a problem that only one gas sensor is attached to the engine head and the evaluation efficiency is poor.
Therefore, an object of the present invention is to provide a gas sensor evaluation method capable of evaluating a plurality of gas sensors in a state in which the gas sensors are cooled to reflect the operation state of an actual internal combustion engine.

In order to solve the above-mentioned problems, a gas sensor evaluation method according to the present invention is provided in an exhaust passage of an internal combustion engine, and a plurality of gas sensors are provided in a jig having a flow hole through which exhaust gas flowing in the exhaust passage can flow. A gas sensor evaluation method for mounting and evaluating the gas sensor by exposing the gas sensor to exhaust gas flowing in the flow hole, wherein the evaluation is performed in a state where the gas sensor is cooled by flowing a fluid through the jig.
According to this gas sensor evaluation method, the gas sensor can be evaluated in a state where the gas sensor is cooled by the traveling wind of the vehicle in the actual internal combustion engine, that is, the operating state of the actual internal combustion engine. In addition, it is possible to prevent the gas sensor from overheating and the component parts and the like from melting.
Moreover, a plurality of gas sensors can be evaluated at the same time, and it is possible to prevent the evaluation efficiency from deteriorating.

In the gas sensor evaluation method of the present invention, the fluid may be water, and the jig may be formed with a water channel through which the water flows, and the gas sensor may be cooled by flowing water through the water channel.
According to this gas sensor evaluation method, the gas sensor can be reliably cooled and evaluated by the water flowing through the water channel.

Furthermore, in the gas sensor evaluation method of the present invention, the jig has a cylindrical shape extending along the flow direction of the exhaust gas, and the plurality of gas sensors are arranged on the jig along the flow direction. The water channel may extend along the flow direction of the jig.
According to this gas sensor evaluation method, a plurality of gas sensors can be simultaneously evaluated with one jig, and the plurality of gas sensors can be reliably cooled and evaluated with water flowing in the water channel. .

Furthermore, in the gas sensor evaluation method of the present invention, a plurality of the water channels may be provided in the jig.
According to this gas sensor evaluation method, a large number of gas sensors can be cooled by a plurality of water channels with one jig.
Moreover, a water channel can be provided corresponding to a plurality of gas sensors, and the gas sensors can be more reliably cooled for evaluation.

Further, in the gas sensor evaluation method of the present invention, the fluid is air, and the jig is formed with an air hole through which the air flows. Even if the gas sensor is cooled by air through the air hole, Good.
According to this gas sensor evaluation method, the gas sensor can be reliably cooled and evaluated by air cooling.

Furthermore, in the gas sensor evaluation method of the present invention, the jig is attached to an outer surface of the cylindrical portion having the flow hole and the cylindrical portion, and forms a gap with the gas sensor. The air hole may be provided in the bed portion, and the gas sensor may be air-cooled by flowing air through the gap in the bed portion.
According to this gas sensor evaluation method, air is allowed to flow through the bed portion with the gas sensor surrounded by the bed portion, so that the gas sensor can be reliably air-cooled.

Furthermore, in the gas sensor evaluation method of the present invention, a plurality of the bed portions are provided, one gas sensor is disposed on each of the bed portions, and air is supplied to the gas sensor from one air hole provided in the bed portion. May be used.
According to this gas sensor evaluation method, each gas sensor is surrounded by a bed portion, and air is allowed to flow through one air hole, so that the gas sensor can be cooled more reliably.

Furthermore, in the gas sensor evaluation method of the present invention, air may flow from the air hole toward the gas sensor so that the air swirls around the axis of the gas sensor in the gap.
According to this gas sensor evaluation method, air swirls around the axis of the gas sensor in the gap, so that the air also contacts the back side of the gas sensor opposite to the air hole, and the gas sensor is cooled evenly. can do.

  Furthermore, in the gas sensor evaluation method of the present invention, the jig may be made of aluminum or an aluminum alloy. If the jig is made of aluminum or an aluminum alloy, the gas sensor can be further cooled because of its high thermal conductivity.

  According to the present invention, it is possible to evaluate a plurality of gas sensors in a state where the gas sensors are cooled reflecting the operation state of the actual internal combustion engine.

It is a side view of a gas sensor. It is a block diagram which shows the 1st test apparatus used for the evaluation method of the gas sensor which concerns on the 1st Embodiment of this invention. It is a perspective view which shows the structure of the jig | tool in a 1st test apparatus. It is a block diagram which shows the 2nd test apparatus used for the evaluation method of the gas sensor which concerns on 2nd Embodiment of this invention. It is sectional drawing which cut | disconnected the bed part along AA shown in FIG. It is a top view of the bed part shown in FIG. It is a top view of the bed part different from FIG.

Hereinafter, embodiments of the present invention will be described.
FIG. 2 is a block diagram showing the first test apparatus 100 used in the gas sensor evaluation method according to the first embodiment of the present invention. The first test apparatus 100 includes an engine (gasoline engine) 10 that is an internal combustion engine of a vehicle, and a hexagonal cylindrical jig 20 connected to an exhaust manifold 12 of the engine 10. A plurality of gas sensor mounting holes (not shown), which will be described later, are opened in the jig 20, and a plurality of gas sensors 50 to be tested are respectively screwed to the gas sensor mounting holes.
Exhaust gas G from each cylinder of the engine 10 is exhausted from the exhaust pipe 14 via the exhaust manifold (exhaust collecting pipe) 12. In the first embodiment, the exhaust gas G is cured between the exhaust manifold 12 and the exhaust pipe 14. By connecting the tool 20, the jig 20 is installed in the exhaust passage of the engine 10, and the exhaust gas G flows through the inside of the jig 20 (flow hole 20h in FIG. 3). In addition, flange portions 21c and 21d are formed at both ends in the flow direction of the jig 20, the flange portion 21c is connected to the flange portion 12f of the exhaust manifold 12, and the flange portion 21d is connected to the flange portion 14f of the exhaust pipe 14. Is done.

  Here, the “exhaust passage” is a path through which exhaust from the cylinder of the engine 10 passes. “Installing in the exhaust passage” may be installed in any position as long as the exhaust from the cylinder of the engine 10 passes. For example, the jig 20 is connected to the downstream side of the exhaust pipe 14. Alternatively, the exhaust pipe 14 may be divided into an upstream exhaust pipe and a downstream exhaust pipe, and the jig 20 may be connected between the upstream exhaust pipe and the downstream exhaust pipe. For example, in the case of a single cylinder engine, the jig 20 may be directly connected to the exhaust port from the cylinder of the engine.

FIG. 3 is a perspective view showing the configuration of the jig 20. The jig 20 is made of hexagonal cylindrical aluminum, and a circulation hole 20h is provided in the center, and the exhaust gas G can be circulated inside the circulation hole 20h.
In the six outer surfaces of the jig 20 (only three outer surfaces 21s1, 21s2, 21s3 are shown in FIG. 3), a plurality of gas sensor mounting holes (in FIG. 3, two outer surfaces 21s2, 21s2, 21s3 are shown). Gas sensor mounting holes 22h1 and 22h2 corresponding to 21s3 are displayed) toward the flow hole 20h. Each gas sensor mounting hole 22h1, 22h2 is formed with a female screw, and the male sensor 50c of the gas sensor 50 is screwed to the gas sensor mounting hole 22h1, 22h2, so that the gas sensor 50 is attached to the jig 20 and the gas sensor 50 The detection element 50b (see FIG. 1) on the distal end side is exposed to the exhaust hole G by being exposed to the flow hole 20h.
As shown in FIG. 1, the gas sensor 50 has a detection element that generates electromotive forces of different sizes or changes resistance values depending on the concentration of, for example, oxygen or NOx (nitrogen oxide). It has the well-known structure provided for.

Inside the six ridge lines on the outer surface of the jig 20 (only four ridge lines 21r1 to 21r4 adjacent to the outer surfaces 21s1, 21s2, and 21s3 are shown in FIG. 3), water channels (see FIG. 3, only four water channels 23h1 to 23h4 are formed inside the four ridgelines 21r1 to 21r4. In addition, inlet-side plugs 23a1 to 23a4 projecting radially outward from the outer surface of the jig 20 are communicated with the upstream ends (flange portion 21c side) of the water channels 23h1 to 23h4, respectively. Similarly, outlet plugs 23b1 to 23b4 projecting radially outward from the outer surface of the jig 20 communicate with the downstream ends (flange portion 21d side) of the water channels 23h1 to 23h4, respectively.
As shown in FIG. 2 (FIG. 2 shows only the inlet side plugs 23a2 to 23a4 and the outlet side plugs 23b2 to 23b4), cooling water hoses 30a2 to 30a4 are connected to the inlet side plugs 23a2 to 23a4, respectively, and cooling is performed. The water hoses 30a2 to 30a4 are configured to flow the cooling water W whose flow rate is adjusted by the flow rate adjusting valves 32 to 34 to the water channels 23h2 to 23h4, respectively.
Further, the cooling water hoses 30b2 to 30b4 are connected to the outlet side plugs 23b2 to 23b4, respectively, and the cooling water W that has flowed into the water channels 23h2 to 23h4 is discharged from the cooling water hoses 30b2 to 30b4 to the outside.
The same applies to the other three water channels (not shown).

Next, a gas sensor evaluation method according to the first embodiment using the first test apparatus 100 will be described. In this gas sensor evaluation method, the gas sensor 50 is supplied to the exhaust gas G circulated through the flow hole 20h of the jig 20 while flowing the cooling water W through the water channels 23h2, 23h3,. The gas sensor 50 is evaluated (for example, durability evaluation) in a state where the engine 10 is operated.
As a result, the gas sensor 50 can be evaluated in a state where the gas sensor 50 is cooled by the traveling wind of the vehicle or the like in the actual engine 10, that is, the operating state of the actual engine 10. It is possible to prevent the component parts and the like from melting due to overheating. In addition, it is possible to perform the evaluation at the same time in a state where the plurality of gas sensors 50 are cooled by one jig 20, and it is possible to prevent the evaluation efficiency from being deteriorated.

  Moreover, in this embodiment, the water channels 23h2, 23h3,... For flowing the cooling water W through the jig 20 are formed, and the gas sensor 50 is cooled by flowing the cooling water W through the water channels 23h2, 23h3,. Thereby, the gas sensor 50 can be reliably cooled and evaluated by water cooling.

  Further, in the present embodiment, the jig 20 has a cylindrical shape extending along the flow direction of the exhaust gas G, and a plurality of gas sensors 50 are arranged in the jig 20 along the flow direction, and the water channels 23h2, 23h3,. -Extends along the flow direction of the jig 20. Thereby, the plurality of gas sensors 50 can be simultaneously evaluated with one jig 20, and the plurality of gas sensors 50 are reliably cooled and evaluated by the cooling water W flowing through the water channels 23h2, 23h3,. It can be performed.

In this embodiment, a plurality of water channels 23h2, 23h3,... Are provided in the radial direction of the jig 20, and the flow rate of the cooling water W flowing through the water channels 23h2, 23h3,. It comes to adjust by. Therefore, the flow rate adjusting valves 32, 33,... Are adjusted to manage the temperature of the gas sensors 50 attached to the outer surfaces 21s1, 21s2,. 20 can be evaluated simultaneously.
If each flow rate adjusting valve 32, 33... Is adjusted so that the temperature of the gas sensor 50 attached to each outer surface 21s1, 21s2. The gas sensor 50 can be simultaneously evaluated under a plurality of different conditions.

FIG. 4 is a block diagram showing a second test apparatus 110 used in the gas sensor evaluation method according to the second embodiment of the present invention. The second test apparatus 110 includes the engine 10 and a jig 30 connected to the exhaust manifold 12 of the engine 10. The jig 30 includes a cylindrical tube portion 31 connected to the exhaust manifold 12 and a plurality (six in FIG. 4) of bed portions 32 to 37 attached to the outer surface of the tube portion 31. A gas sensor 50 is accommodated inside each of the bed portions 32 to 37. A detailed configuration of each of the bed portions 32 to 37 will be described later.
The exhaust gas G from each cylinder of the engine 10 is exhausted from the exhaust pipe 14 via the exhaust manifold (exhaust collecting pipe) 12. In the second embodiment, a cylinder is provided between the exhaust manifold 12 and the exhaust pipe 14. By connecting the part 31, the cylinder part 31 is installed in the exhaust passage of the engine 10, and the exhaust gas G flows through the inside of the cylinder part 31 (circulation hole 31 a in FIG. 5). Note that flange portions 31c and 31d are formed at both ends of the cylindrical portion 31 in the flow direction, the flange portion 31c is connected to the flange portion 12f of the exhaust manifold 12, and the flange portion 31d is connected to the flange portion 14f of the exhaust pipe 14. Is done.

Of the bed portions 32 to 37, the three bed portions 32 to 34 are arranged on the upper surface of the cylinder portion 31 so as to be separated from each other in the flow direction, and the other three bed portions 35 to 37 are the cylinder portion 31. Are spaced apart from each other along the flow direction. The bed portions 32 and 35, the bed portions 33 and 36, and the bed portions 34 and 37 are opposed to each other via the cylinder portion 31.
Branch pipes 39a1 and 39a2 from the air pipe 39a are connected to the bed portions 32 and 35, respectively. Similarly, branch pipes 39b1 and 39b2 from the air pipe 39b are connected to the bed portions 33 and 36, respectively. Branch pipes 39c1 and 39c2 from the air pipe 39c are connected to the bed portions 34 and 37, respectively.
The air Air whose flow rate is adjusted by the regulators 38a to 38c of the air pipes 39a to 39c is caused to flow to the bed portions 32 to 37, and the gas sensors 50 housed in the bed portions 32 to 37 are air-cooled. It has become.

FIG. 5 is a cross-sectional view of the bed portion 32 taken along the line AA shown in FIG. In addition, since all the bed parts 32-37 are the same structures, the bed part 32 is demonstrated as a representative example.
The bed portion 32 has a substantially bottomed cylindrical shape, and is attached to the outer surface of the cylindrical portion 31. The bed portion 32 extends from the outer edge of the bottom surface 32 b, and forms an annular side wall portion that surrounds the gas sensor 50 while forming a gap with the gas sensor 50. 32s and one pipe joint part 32a attached to the outer surface of the side wall part 32s and connecting the branch pipe 39a1. The side wall 32s has a nozzle hole 32c that extends perpendicularly to the direction of the axis O of the gas sensor 50 and communicates with the inside of the joint 32a, and blows out air Air. The nozzle hole 32c corresponds to an “air hole” in the claims.
The air Air blown to the gas sensor 50 from the nozzle hole 32c is discharged from the upper side of the side wall portion 32s to the outside of the bed portion 32.
On the other hand, a gas sensor attachment hole 32h is opened at the center of the bottom surface 32b, and the gas sensor attachment hole 32h communicates with an opening 31h provided in the cylindrical portion 31. A female screw is formed in the gas sensor mounting hole 32h, and the male sensor 50c of the gas sensor 50 is screwed to the gas sensor mounting hole 32h, whereby the gas sensor 50 is mounted on the cylindrical portion 31 and the detection element on the tip side of the gas sensor 50. 50 b (see FIG. 1) is exposed inside the cylindrical portion 31 and exposed to the exhaust gas G.

Next, a gas sensor evaluation method according to the second embodiment using the second test apparatus 110 will be described. In this gas sensor evaluation method, the gas sensor 50 is supplied to the exhaust gas G circulated through the flow hole 31a of the cylindrical portion 31 while air is blown to the gas sensor 50 housed in the bed portions 32 to 37 to cool the gas sensor 50. The gas sensor 50 is evaluated (for example, durability evaluation) in a state where the engine 10 is operated.
Thereby, also in the second embodiment, it is possible to evaluate the gas sensor 50 reflecting the state in which the gas sensor 50 is cooled by the traveling wind of the vehicle in the actual engine 10, that is, the operation state of the actual engine 10. In the evaluation, it is possible to prevent the gas sensor 50 from overheating and the component parts and the like from being melted. In addition, it is possible to perform the evaluation at the same time in a state where the plurality of gas sensors 50 are cooled by one jig 30, and it is possible to prevent the evaluation efficiency from being deteriorated.

  Further, in the present embodiment, the nozzle hole 32c for flowing the air Air is formed in the jig 30, and the gas sensor 50 is air-cooled by flowing the air Air to the nozzle hole 32c. Thus, the gas sensor 50 can be reliably cooled and evaluated by air cooling.

  Further, in the present embodiment, the jig 30 includes a cylindrical tube portion 31 having a flow hole 31a, and a bed portion that is attached to the outer surface of the tube portion and surrounds the gas sensor 50 while forming a gap with the gas sensor 50. 32, and the air sensor is air-cooled by flowing air Air through the gap in the bed portion 32. Thereby, since the air Air is allowed to flow through the bed portion 32 in a state where the gas sensor 40 is surrounded by the bed portion 32, the gas sensor 50 can be reliably air-cooled.

  Further, in the present embodiment, a plurality of bed portions 32 are provided, and one gas sensor 50 is arranged in each bed portion 32, and air Air is caused to flow to the gas sensor 50 from one nozzle hole 32 c provided in the bed portion 32. Yes. Accordingly, each gas sensor 50 is surrounded by the bed portion 32 and air Air is allowed to flow from one nozzle hole 32c, so that the gas sensor 50 can be air-cooled more reliably.

  As shown in FIG. 6, in the present embodiment, the air flow direction F from the nozzle hole 32 c toward the gas sensor 50 (that is, the direction in which the nozzle hole 32 c extends) is such that the opening of the gap between the nozzle holes 32 c and the gas sensor 50. Intersects with a straight line L connecting the axis O. As a result, the air Air is shifted from the nozzle hole 32c with respect to the straight line L and blown to the gas sensor 50. As a result, the air Air swirls around the axis O of the gas sensor 50 and flows. In this way, since the air Air flows from the nozzle hole 32c toward the gas sensor 50 so that the air Air swirls around the axis of the gas sensor 50 in the gap, the gas sensor on the side opposite to the nozzle hole 32c. The air Air also contacts the back side 51 of the gas 50, and the gas sensor 50 can be air-cooled more evenly.

  On the other hand, as shown in FIG. 7, when the flow direction F is parallel to the straight line L, air Air is blown from the nozzle holes 32 c to the gas sensor 50 symmetrically with respect to the straight line L. No air swirl flows around the air hole, making it difficult for the air Air to enter the back surface 51 of the gas sensor 50 with respect to the nozzle hole 32c.

It goes without saying that the present invention is not limited to the above-described embodiment, but extends to various modifications and equivalents included in the spirit and scope of the present invention.
For example, the configuration of the gas sensor 50 is not limited to the above embodiment. The configuration of the jigs 20 and 30 is not limited to the above-described embodiment, and any structure may be used as long as a plurality of gas sensors 50 can be attached. The exhaust passage in which the jigs 20 and 30 are installed is not limited to the above embodiment.
Note that it is preferable that the jigs 20 and 30 are made of aluminum or an aluminum alloy because the gas sensor 50 can be further cooled because the thermal conductivity is high.

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 12,14 Exhaust passage 20,30 Jig 20h, 31a Flow hole 23h2-23h4 Water channel 31 Tube part 32-37 Bed part 32c Air hole (nozzle hole)
50 Gas sensor G Exhaust gas W Cooling water (fluid)
Air air (fluid)
F Air flow direction L Straight line connecting air hole and gas sensor axis O Gas sensor axis

Claims (9)

A plurality of gas sensors are attached to a jig having a flow hole through which the exhaust gas flowing through the exhaust passage can flow, and the gas sensor is exposed to the exhaust gas flowing through the flow hole. A gas sensor evaluation method for evaluating a gas sensor,
A gas sensor evaluation method for performing the evaluation in a state in which a fluid is flowed into the jig to cool the gas sensor.   The gas sensor evaluation method according to claim 1, wherein the fluid is water, and the jig is formed with a water channel through which the water flows. The gas sensor is cooled by flowing water through the water channel.   The jig has a cylindrical shape extending along the flow direction of the exhaust gas, the plurality of gas sensors are arranged in the jig along the flow direction, and the water channel is formed through the flow of the jig. The method for evaluating a gas sensor according to claim 2, which extends along a direction.   The gas sensor evaluation method according to claim 3, wherein a plurality of the water channels are provided in the jig.   The gas sensor evaluation method according to claim 1, wherein the fluid is air, and an air hole through which the air flows is formed in the jig, and the gas sensor is air-cooled by flowing air into the air hole. The jig includes a cylindrical tube portion having the flow hole, and a bed portion that is attached to an outer surface of the tube portion and surrounds the gas sensor while forming a gap with the gas sensor.
The gas sensor evaluation method according to claim 5, wherein the air hole is provided in the bed portion, and the gas sensor is air-cooled by flowing air through the gap in the bed portion.   The gas sensor evaluation according to claim 6, wherein a plurality of the bed portions are provided, the gas sensors are arranged one by one in each of the bed portions, and air is caused to flow from the one air hole provided in the bed portion to the gas sensor. Method.   The gas sensor evaluation method according to claim 7, wherein air flows from the air hole toward the gas sensor so that the air swirls around the axis of the gas sensor in the gap.   The method for evaluating a gas sensor according to claim 1, wherein the jig is made of aluminum or an aluminum alloy.

Images