JPS6037310B2 - Engine exhaust gas reformer - Google Patents

Description

Detailed Description of the Invention The present invention extracts a part of exhaust gas emitted from an engine, mixes it with fuel, and uses the heat of the exhaust gas to reduce the calorific value under a modified catalyst. This device improves fuel efficiency by reforming the fuel into an increased amount of reformed fuel and supplying this reformed fuel to the intake passage of the engine.In particular, it is a device that improves fuel efficiency by converting engine exhaust heat and the catalytic oxidation reaction of unburned components in the exhaust gas. The present invention relates to a device that can improve reforming efficiency by efficiently transmitting heat generated by waste catalyst to waste catalyst.

The exhaust gas reforming device is provided with a heat exchanger in the middle of the exhaust passage of an engine, and has an exhaust gas passage in the heat exchanger through which the exhaust gas in the exhaust passage passes, and an exhaust gas passage that is cut off from the exhaust gas passage. A reforming reaction chamber is provided in which heat exchange is performed with the exhaust gas passage through a heat exchange wall, and a part of the exhaust gas that has passed through the exhaust gas passage is added with fuel and guided to the reforming reaction chamber,
A reforming reaction, that is, a catalytic endothermic reaction is carried out in the reforming reaction chamber to produce reformed fuel containing carbon monoxide and hydrogen, which is then supplied to the intake passage of the engine.

By the way, in such a device, in order to carry out the above reforming reaction smoothly, it is necessary to supply the reforming catalyst with the heat necessary for the reaction. It is difficult to obtain a sufficient amount of heat just by transmitting it into the chamber, and when the reforming catalyst is packed in the reforming reaction chamber in the form of particles, most of the heat is transferred from the heat exchange wall through the gas in the pure reaction chamber. This causes a problem in that the heat loss increases and the amount of heat supplied to the reforming catalyst is insufficient, making it impossible for the reforming reaction to proceed smoothly.

The purpose of the present invention is to provide an apparatus that solves the above problems, and efficiently transfers the reaction heat generated by the catalytic oxidation reaction of unburned components in the exhaust gas to the reforming catalyst together with the exhaust heat. The present invention is characterized in that the reforming reaction can be carried out smoothly under sufficient heat supply.

The illustrated embodiment will be described below.

FIG. 1 shows a first embodiment of the present invention, in which 1 is an internal combustion engine, 2 is an intake passage, 3 is an exhaust passage, and 4 is a heat exchanger provided in the middle of the exhaust passage 3. In FIG.

Inside the heat exchanger 4, as shown in FIGS. 2 and 3, there is an exhaust gas passage 5 for passing the exhaust gas on the upstream side in the exhaust passage 3 to the downstream side, and a cut off,
A reforming reaction chamber 7 is provided in which heat exchange is performed with the exhaust gas passage 5 via a heat exchange wall 6, and as shown in FIG. The waste product reaction chamber 7 is connected to the exhaust gas conduit 8, and the reforming reaction chamber 7 and the intake passage 2 are connected to each other by a reformed fuel conduit 9.

A fuel supply means 10 for supplying CmHn fuel is provided in the middle of the exhaust gas conduit 8. Gasoline, diesel oil, alcohol, etc. can be used as the CmHn fuel, and a fuel injection valve or the like can be used as the fuel supply means 10. In the middle of the reformed fuel conduit 9, there is a flow rate adjustment valve 1 for adjusting the flow rate of the reformed fuel.
1 is provided, and a filter 12 is provided on the inflow side of the valve 11. In addition to the above, a reformed fuel cooler (not shown) may be provided in the middle of the reformed fuel conduit 9 as required.
The heat exchange walls 6 are made of a material having a substantially comb-shaped cross section as shown in FIG. The container 4 is roughly configured.

3 to 5, the wall surface of the heat exchange wall 6 on the side of the reforming reaction chamber 7 is composed of a reforming catalyst 13, and the wall surface of the heat exchange wall 6 on the side of the exhaust gas passage 5 is composed of an exhaust gas purification catalyst 14. It consists of

Here, the heat exchange wall 6 is made of a porous material such as alumina, and a reforming catalyst 13 and an exhaust gas purification catalyst 14 are attached to each wall surface by means such as thermal spraying, so that each wall surface is covered with a catalyst 13. , 14. As the reforming catalyst 13, at least cobalt,
A catalyst containing either nickel or rhodium can be used, and the exhaust gas purification catalyst 14 may contain at least platinum, platinum. An oxidation catalyst or three-way catalyst containing either rhodium or nickel can be used.

In the exhaust gas reforming device configured as described above, the exhaust gas discharged from the combustion chamber of the internal combustion engine 1 passes through the exhaust gas passage 5 of the heat exchanger 4 located in the middle of the exhaust passage 3, and reaches the downstream side of the exhaust passage 3. be discharged.

When the exhaust gas passes through the passage 5, unburned components in the exhaust gas, such as carbon monoxide and hydrocarbon, undergo an oxidative exothermic reaction on the surface of the exhaust gas purification catalyst 14, and this reaction heat and the exhaust gas contained in the exhaust gas are The combustion is transferred from the surface of the exhaust gas purification catalyst 14 to the inside of the heat exchange wall 6 by heat conduction, and is further transferred by heat conduction to the reformer 13 that constitutes the side wall surface of the reforming reaction chamber 7 of the heat exchange wall 6. be done. In this way, the reforming catalyst 1
3 is added to the activation temperature, but since the reforming catalyst 13 is supplied with the above-mentioned reaction heat and exhaust heat, the absolute amount of heat increases. Since there is no gas or the like involved, there is almost no heat loss and heat is efficiently supplied. A part of the exhaust gas coming out of the heat exchanger 4 is sucked into the exhaust gas conduit 8 by the negative pressure in the intake passage 2, and is mixed with the CmHn fuel spouted from the fuel supply means 10 to form an air-fuel mixture. , enters the reforming reactant 7. The air-fuel mixture that has entered the reforming reaction chamber 7 undergoes a reforming endothermic reaction on the surface of the activated reforming catalyst 13, and becomes reformed fuel containing a large amount of carbon monoxide and hydrogen.

Now, when C7.6H, 3.6 is used as CmHn fuel, the reforming reaction is carried out as shown in the following equation. i. 5K7.
Target 026. Thin 20144N2) 10*7.6 days. 3.6
138 is cal'mol (exhaust gas)
(Fuel) 31st 234-7C〇168-mother N2G secondary fuel) As can be seen from the above equation, this reaction requires 38 pine Cal/mo
1 of heat is required, but as mentioned above, the reaction heat of the exhaust gas and the exhaust heat are efficiently supplied in large quantities to the reforming catalyst 13, so the reaction in the above equation is carried out smoothly. .

The generated reformed fuel passes through the reformed fuel conduit 9, is purified by the filter 2, and then is sucked into the intake passage 2 after its flow rate is adjusted by the flow rate regulating valve 11. In this way, the intake passage 2 of the internal combustion engine 1 is supplied with political fuel whose calorific value is increased by recovering the energy contained in the exhaust gas, thereby improving fuel efficiency. 7 and 8 show a second embodiment of the present invention, in which a heat exchange wall 6 is sprayed onto a metal material 15 having a substantially comb-shaped cross section and a surface of the material 15. A porous material layer 16 made of alumina or the like is deposited on the surface of the porous material layer 16 on the reforming reaction chamber 7 side.
3, the wall surface of the heat exchange wall 6 on the waste material reaction chamber 7 side is configured with the reforming catalyst 13, and the exhaust gas purification catalyst 14 is formed on the surface of the porous material layer 16 on the exhaust gas passage 5 side. By attaching it, the heat exchange wall 6 on the exhaust gas passage 5 side
This embodiment is characterized in that the wall surface of the embodiment is composed of an exhaust gas purification catalyst 14, and since the other components are the same as those of the first embodiment, a description thereof will be omitted. The device of this example also provides the same effects as those of the first example. FIG. 8 shows the third embodiment of the present invention.
This example shows a heat exchange wall 6 and a reforming catalyst 1.
3 and the exhaust gas purification catalyst 14 by using a metal material containing a large amount of nickel.
The wall surface of the heat exchange wall 6 on the side of the reforming reaction chamber 7 is composed of a reforming catalyst 13, and the wall surface of the heat exchange wall 6 on the side of the exhaust gas passage 5 is composed of an exhaust gas purification catalyst 14. Since the configuration of the second embodiment is the same as that of the first embodiment, the explanation thereof will be omitted.

The device of this example not only provides the same effects as those of the first example, but also simplifies the heat exchange wall structure and facilitates manufacturing. FIG. 9 shows a fourth embodiment which is a further modification of the third embodiment, in which numerous grooves are formed on the wall surface of the heat exchange wall 6 made of a metal material containing a large amount of nickel by means such as corrosion. In this example, compared to the third example, the political catalyst 1 is
3 and the catalyst surface of the exhaust gas purification catalyst 14 can be increased, and the reforming efficiency can be further improved.

10 and 11 show a fifth embodiment of the present invention, which shows a modified array of heat exchangers 4. FIG.

Here, between each flat plate 17, 17..., wavy plates 18, 19
are interposed alternately in directions orthogonal to each other, the reforming reaction chamber 7 sandwiching the corrugated plate 18 and the exhaust gas passage 5 sandwiching the corrugated plate 19.
are alternately formed in multiple layers, with the flat plate 17 and the corrugated plate 18
, 19 constitute a heat exchange wall 6. Here, by attaching the reforming catalyst 13 to the surface of the corrugated plate 18, the wall surface of the heat exchange wall 6 on the reforming reaction chamber 7 side is made up of the reforming catalyst 13, and the exhaust gas is applied to the surface of the corrugated plate 19. Purification catalyst 1
4, the wall of the heat exchange wall 6 on the side of the exhaust gas passage 5 is made up of the exhaust gas purification catalyst 14. Since the other components are the same as those in the first embodiment, their explanation will be omitted. In this example, the same effects as in the first example can be obtained. 12 and 13 show a sixth embodiment of the present invention, in which the heat exchanger 4 is a shell-and-tube heat exchanger device.

Here, the heat exchange wall 6 is a heat transfer tube, and the wall surface, that is, the outer peripheral surface on the waste reaction chamber 7 side of each heat transfer support 6 is constituted by a reforming catalyst 13,
The wall surface, ie, the inner peripheral surface, on the side of the exhaust gas passageway 5 is constituted by an exhaust gas purification catalyst 14. The other components are the same as those in the first embodiment, so their explanation will be omitted. In this example, the same effects as in the first example can be obtained. 14 and 15 show a seventh embodiment of the present invention, which is a further modification of the sixth embodiment.

That is, here, the heat exchange wall 6 is a heat exchanger tube having a large number of fins on the outer periphery, and the wall surface of each heat exchanger tube 6 on the exhaust gas passage 5 side, that is, the inner peripheral surface is constituted by the exhaust gas purification catalyst 14, The wall surface on the reforming reaction chamber 7 side, that is, the outer circumferential surface of the heat exchanger tube 6 and the surface of the fins are made of a reforming catalyst 13. Since the other components are the same as those in the first embodiment, their explanation will be omitted. In this example, the heat transfer area and the reforming catalyst surface can be increased compared to the sixth example, and the reforming efficiency can be improved. In addition, in the fifth to seventh embodiments, each wall surface of the heat exchange wall is configured with the reforming catalyst 13 or the exhaust gas purification catalyst 14 in any one of the modes explained in the first to fourth embodiments. Needless to say, it can be applied.

The example in which the present invention is applied to an internal combustion engine has been described above.
The present invention can also be applied to external combustion engines in the same manner as described above.

As explained above, the present invention is characterized in that the wall surface of the heat exchange wall on the polymer reaction chamber side is composed of a reforming catalyst, and the wall surface of the heat exchange wall on the exhaust gas passage side is composed of an exhaust gas purification catalyst. , the reaction heat generated by the catalytic oxidation reaction of unburned components in the exhaust gas can be transferred to the reforming catalyst together with the exhaust heat of the exhaust gas, and the absolute amount of heat can be increased, and this heat can be It becomes possible to efficiently transmit the transmission to the reforming catalyst by heat conduction.

As a result, the amount of heat supplied to the reforming catalyst increases, the endothermic reforming reaction is carried out smoothly, and the production rate of reformed fuel increases. Furthermore, since the unburned components in the exhaust gas in the exhaust gas passage are subjected to an oxidation reaction, the exhaust gas can be purified at the same time, increasing the product value.

Furthermore, since exothermic and endothermic reactions are simultaneously carried out on both wall surfaces of the heat exchange wall, it is possible to prevent the catalyst on the heat generating side, that is, the exhaust gas purification catalyst, from overheating, thereby extending its life. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway front view of a part of an internal combustion engine and the entire exhaust gas reforming device showing a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view of the heat exchanger in FIG. 1. FIG. 3 is a cross-sectional view of section A in FIG. 2 viewed in the direction of the arrow. FIG. 4 is a cross-sectional view of section B in FIG. 2 viewed in the direction of the arrow. FIG. 5 is an enlarged cross-sectional view of a part of FIG. 4. FIG. 6 is a partial perspective view showing one of the heat exchange walls of the first embodiment. FIG. 7 is a sectional view corresponding to FIG. 5, showing a second embodiment of the present invention. FIG. 8 is a sectional view corresponding to FIG. 5, showing a third embodiment of the present invention. FIG. 9 is a cross-sectional view at a position corresponding to FIG. 5, showing a fourth embodiment of the present invention. FIG. 10 shows the fifth embodiment of the present invention.
FIG. 1 is a perspective view of a heat exchanger showing an example. FIG. li is an enlarged perspective view of a portion of FIG. 10. FIG. 12 is a longitudinal sectional view of a heat exchanger showing a sixth embodiment of the present invention. FIG. 13 is an enlarged sectional view of the section line D in FIG. 12, viewed in the direction of the arrow. FIG. 14 is a longitudinal sectional view of a heat exchanger showing a seventh embodiment of the present invention. FIG. 15 is an enlarged cross-sectional view of a part of FIG. 14. 1...
・...Internal combustion engine, 2...Intake passage, 3...
・Exhaust passage, 4... Heat exchanger, 5... Exhaust gas passage, 6... Heat exchange wall, 7... Reforming reaction chamber,
8...Exhaust gas pipe, 9...Reformed fuel pipe, 10...Fuel supply means, 13...Waste catalyst, 14... Exhaust gas purification catalyst.

Figure 1 Figure 2 Figure 3 Figure 4 Figure 6 Figure 5 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 Figure 14 Figure 15

Claims (1)

[Claims] 1. A heat exchanger is provided in the middle of the exhaust passage of the engine, and there is an exhaust gas passage through which the exhaust gas in the exhaust passage passes through the heat exchanger, and an exhaust gas passage which is cut off from the exhaust gas passage and passes through the exhaust gas through a heat exchange wall. A reforming reaction chamber is provided in which heat exchange is performed with the exhaust gas passage, and the exhaust passage and the reforming reaction chamber are connected by an exhaust gas conduit having a fuel supply means in the middle, and the reforming reaction chamber is connected to the reforming reaction chamber. and the intake passage of the engine are connected through a reformed fuel conduit, the wall surface of the heat exchange wall on the side of the reforming reaction chamber is constituted by a reforming catalyst, and the wall surface of the heat exchange wall on the side of the exhaust gas passageway is configured An exhaust gas reforming device for an engine characterized by comprising an exhaust gas purification catalyst.