JPS6227245B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention aims to purify the exhaust gas by re-burning unburned components in the engine exhaust gas using a catalyst, and also to utilize the thermal energy of the exhaust gas which has become even hotter due to the re-burning. The present invention relates to an exhaust heat recovery device that efficiently absorbs and recovers heat in liquid such as water or gas.

An example of an exhaust heat recovery device is one that absorbs exhaust heat by flowing a heat exchange liquid directly around the catalyst. The water becomes condensed water mixed with carbon and is released to the outside, polluting the surrounding area.

In addition, during a cold start of the engine when the catalyst temperature is low, the catalyst is cooled by the heat exchange liquid, so it takes a considerable amount of time for the catalyst to reach a high enough temperature to work properly, and during that time the exhaust gas is left untreated. There is a problem in that it is released without any change.

Therefore, it is possible to shorten the temperature rise time of the catalyst by forming an adiabatic space between the catalyst and the heat exchange liquid, but in this case, the temperature of the catalyst becomes too high during operation, and the catalyst cannot be supported. There were problems in that the support material used for the catalyst was destroyed by burnout, causing the catalyst to rattle, and the catalyst was damaged by engine vibration, resulting in poor durability.

The present invention was proposed to solve the above problems, and when the temperature of the catalyst is low, exhaust gas from a heat exchanger is blown around the catalyst to heat the catalyst via a heat conductor. While allowing the catalyst to quickly rise in temperature, when the catalyst is at a high temperature, the exhaust gas cooled by the heat exchanger is used to cool the catalyst and catalyst support via a heat conductor. An object of the present invention is to provide a method and device for recovering exhaust heat that prevents thermal breakdown.

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a schematic diagram of a heat pump system using an engine as a power source and a heat source.A two-stroke engine 1 drives a refrigerant compressor 3 in a cooling system 2, and uses engine cooling water for heating and hot water supply. It is guided to the hot water storage tank 4 for heat exchange,
In addition, the engine exhaust is re-combusted in the catalyst cylinder 5, and the engine cooling water is guided to the heat exchanger R incorporated in the catalyst cylinder 5 to recover the exhaust heat, after which the exhaust heat is muffled by the muffler M and sent to the outside. released to.

FIG. 2 shows details of the heat exchange type catalyst cylinder 5 as the exhaust heat recovery device 6, and shows the catalyst cylinder main body 7 divided into three bottomed cylinders: an inner cylinder 8, a middle cylinder 9, and an outer cylinder 10. The inner cylinder 8 has an exhaust inlet 11 at its bottom and a catalyst chamber 1 inside.
2 and an exhaust outlet 13 are formed.

In the catalyst chamber 12, two catalysts 14 are mounted on the catalyst support 1.
The catalyst support 15 suppresses the vibration of the catalyst due to the vibrations of the engine 1, and also supports the catalyst 14 between the inner cylinder 8 and the catalyst chamber 12.
It is fixed inside.

When the inner cylinder 8 formed in this manner is inserted into the heat insulating chamber 16 formed inside the middle cylinder 9, a heat insulating space is formed around the inner cylinder 8.

A box-shaped exhaust outlet 17 is opened toward the exhaust inlet 11 in the heat insulating chamber 16 between the exhaust inlet 11 of the inner cylinder 8 and the bottom of the middle cylinder 9. The support tube 18 is fixedly fixed by passing through the tube 10 and the middle tube 9, and is fixedly supported between the upper end of the support tube 18 and the lower end of the heat retention tube 19 hanging down from the middle tube 9, and an exhaust pipe 20 is inserted into the inside of the support tube 18. It's worn. This exhaust pipe 20 includes an exhaust pipe 21 and an exhaust port 22.
It communicates with the combustion chamber 23 via.

Further, an exhaust shielding plate 24 and an intermediate heat conductor 25 are attached to the inner surface of the middle cylinder 9.
The free end 24a of the intermediate heat conductor 25 contacts the outer circumferential surface 8a near the exhaust inlet 11 of the inner cylinder 8, and the left and right free ends 25a of the intermediate heat conductor 25 contact the outer circumferential portion 8b of the inner cylinder 8 where the catalyst 14 is provided. The inner cylinder 8 is supported within the inner cylinder by abutting on each of the inner cylinders.

Note that the intermediate thermal conductor 25 constitutes a thermal conductor T with the contact portions 8b and 9a of the inner cylinder 8 and the intermediate cylinder 9 with which it comes into contact.

A middle cylinder 9 having an inner cylinder 8 therein is covered with an outer cylinder 10, and a cooling chamber 26 is formed between the middle cylinder 9 and the outer cylinder 10. This cooling chamber 26 is formed with a cooling chamber inlet 27 through which exhaust gas discharged from a heat exchanger R (to be described later) flows in, and an atmosphere discharge port 28 is provided at the bottom of the outer cylinder 10.

This cooling chamber inlet 27 is formed in the outer cylinder 10 directly above the middle cylinder part 9a, which is in contact with the intermediate heat transfer body 25 that fixes the inner cylinder 8 to the middle cylinder 9. A drainage port 29 formed by a hole is provided.

These inner cylinder 8, middle cylinder 9, and outer cylinder 10 each have a flange 33 formed on the exhaust outlet 13 side.
The heat exchange type muffler 5 is assembled together with the flange portion 34 by fastening with bolts 35.

Heat exchanger R receives cooling water from engine 1 through inlet 36
A pair of head tanks 40 and 41 connected by a group of thin tubes 39 for heat exchange are housed inside a jacket-shaped heat exchange case 38 that is introduced from the exhaust port and flows out from the exhaust port 37. An exhaust gas introduction pipe 42 is connected to the flange board 43, and an exhaust pipe 44 is formed outward from the head tank 41 on the discharge side.

This exhaust pipe 44 and the cooling chamber inlet 27 provided in the above-mentioned outer cylinder 10 are communicated through a connecting pipe 45.

The operation of the exhaust gas recovery device 6 configured as above will be explained next.

First, when the exhaust heat recovery device 6 wants to cool down, such as during a cold start of the engine 1, the relatively warm exhaust gas released from the exhaust pipe 44 of the heat exchanger R is guided through the connecting pipe 45 to the outer cylinder 10. The catalyst 14 is supplied from the engine 1 because it is blown into the cooling chamber 26 inside and warms the catalyst 14 from the outer periphery of the middle cylinder 9 via the intermediate heat conductor 25 and the catalyst support 15, and prevents heat dissipation of the catalyst 14. The high-temperature exhaust gas instantly becomes hot, and the exhaust gas is quickly re-burned.

Next, when the exhaust heat recovery device 6 is at a high temperature, such as when the engine 1 is running, the exhaust gas that has become high temperature after being re-combusted by the catalyst 14 is transferred to the heat exchanger R.
The temperature of the catalyst 14 is significantly lower than that of the catalyst 14 and is sent to the cooling chamber 26 in the outer cylinder 10 through the connecting pipe 45, so that the intermediate heat conductor 25 and the catalyst support 15 are heated with this relatively low temperature exhaust gas. through catalyst 1
4 to prevent the catalyst 14 and catalyst support 15 from reaching abnormally high temperatures.

The present invention is configured and operates as described above, and therefore has the following effects.

That is, according to the method of the present invention, when the temperature of the catalyst is low, such as during a cold start of the engine, the exhaust gas from the heat exchanger warms the catalyst via the heat conductor, so that the catalyst is heated immediately after the engine is started. This allows the exhaust gas to be quickly re-combusted.
Also, while the engine is running, the exhaust gas that has become high in temperature due to the re-combustion process is absorbed by the heat exchanger and becomes low in temperature, and this low-temperature exhaust gas cools the catalyst and catalyst support via the heat conductor. This prevents the catalyst support from being burnt out due to abnormal temperature rise of the catalyst, and prevents the catalyst from rattling and being damaged due to engine vibration due to burnout of the catalyst support, increasing its durability.

In addition, according to the device of the present invention, even if condensed water is formed in the exhaust gas that is cooled by the heat exchanger and sent to the cooling chamber, this condensed water is evaporated again due to the high heat of the catalyst, so that the condensed water is not released. Contamination of the surrounding area can be prevented.

Further, the structure for achieving the above effect is a simple structure in which the exhaust gas discharged from the exhaust pipe of the heat exchanger flows into a cooling chamber formed around the catalyst, and can be implemented at low cost.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a heat pump system using an engine as a power source and a heat source, and FIG. 2 is a longitudinal sectional view of a heat exchange type muffler. DESCRIPTION OF SYMBOLS 1... Engine, 8... Inner cylinder, 8b... Part 8, 9... Middle cylinder, 9a... Part 9, 10... Outer cylinder, 11... Exhaust inlet, 12... Catalyst chamber, 13 …
...Exhaust outlet, 14...Catalyst, 15...Catalyst support, 16...Insulation chamber, 22...Exhaust port, 23
... Combustion chamber, 25 ... Intermediate heat conductor, 26 ... Cooling chamber, 27 ... Cooling chamber inlet, R ... Heat exchanger, T
...A thermal conductor.

Claims (1)

[Claims] 1. Engine exhaust heat recovery method that takes the following steps (a) to (c): (b) Pass the exhaust gas with the unburned content burned through the heat exchanger R, recover the exhaust heat in the heat exchanger R, and (c) cool the exhaust gas by heat exchange. The exhaust gas is brought into contact with the heat conductor T, and the catalyst support 15 that supports the outer peripheral portion of the catalyst 14 is cooled by the exhaust gas via the heat conductor T. 2 Insert the inner cylinder 8, the middle cylinder 9, and the outer cylinder 10 three times inside and outside, and create a catalyst chamber 12 in the inner cylinder 8 and a heat insulation chamber 1 in the middle cylinder 9.
6. A cooling chamber 26 is formed in the outer cylinder 10, and a catalyst chamber 1 is formed inside the outer cylinder 10.
The exhaust inlet 11 of the engine 1 is connected to the combustion chamber 23 of the engine 1 via an exhaust port 22, the catalyst 14 is accommodated in the catalyst chamber 12, and the outer circumference of the catalyst 14 is connected to the catalyst support 1.
The outlet 13 of the catalyst chamber 12 is connected to the inlet 27 of the cooling chamber 26 via the heat exchanger R.
The contact portion 8b of the catalyst support 15 of the inner cylinder 8
The intermediate heat conductor 25 is brought into contact with the intermediate heat conductor 25 and the inner cylinder 9, and the heat conductor T is constituted by the inner cylinder part 8b and the middle cylinder part 9a that are in contact with the intermediate heat conductor 25. Engine exhaust heat recovery device. 3 In the exhaust heat recovery device described in claim 2, the middle cylinder portion 9 constituting the heat conductor T
The inlet 27 of the cooling chamber 26 is shown in a. 4. The exhaust heat recovery device according to claim 3, in which a discharge port 29 for condensed water in the exhaust gas is provided at a position below the cooling chamber inlet 27 of the outer cylinder 10.