JP3231472U - Small combustion heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate a problem due to carbonization of fuel in a fuel pipe, which can be mounted on an automobile and used for various heating means such as interior heating, a system having a short warm-up time and a quick heat generation ability. We provide a compact combustion heater system that never happens. SOLUTION: Air and vaporized fuel generated by vaporizing liquid fuel by a fuel evaporation pipe 19 are mixed to generate an air-fuel mixture, and the mixture is mixed via a burner top 23 having a plurality of nozzles 24 for blowing out the air-fuel mixture. In a combustion type heater that heats cooling water by introducing air into a combustion chamber and guiding this combustion gas to a heat exchanger provided downstream of the combustion chamber, the fuel evaporation pipe 19 is close to the combustion chamber wall 32. , And arranged so as to be close to the burner top 23. [Selection diagram] Fig. 4

Description

The present invention is a heater that heats water via a heat exchanger with a burner that vaporizes liquid fuel and premixes it with air to burn it, and is a device for a small heater that can be mounted on a vehicle.

Conventionally, the exhaust heat generated by an internal combustion engine for an automobile has been used as a heat source for an in-vehicle heater. However, in recent years, as the efficiency of the internal combustion engine has improved, the ratio of this exhaust heat has decreased, causing problems such as insufficient heat of the heater, long warm-up time of the engine, and difficulty in starting the heater. In cold regions, heating of automobiles is one of the important functions, and if the heating function is insufficient, it may lead to life or death problems.

Against this background, a compact combustion heater that can be mounted on a vehicle using liquid fuel has been put into practical use. For example, European manufacturers Webasto, Webastocher, etc. provide a system that heats the cooling water of the engine with a small combustion heater and assists the heating capacity for the finished vehicle and aftermarket for cold regions. ..

The small combustion heater system popularized by these manufacturers in the market vaporizes fuel using a fuel vaporizer made of metal mesh, so it takes time to warm up the fuel vaporizer when the system starts. It takes 2 to 3 minutes for the system to reach a steady operation that exhibits sufficient heat generation capacity, and there is a problem that it cannot quickly respond to the heating request.

A small combustion heater system can be installed in automobiles to accelerate the heating of cooling water at start-up as well as to assist heating and use it for improving fuel efficiency, or to accelerate the warming up of catalysts to improve emissions. In order to use it for the purpose, it is necessary to quickly respond to the heating demand that changes according to the driving situation of the automobile.

Therefore, as shown in FIG. 5, a configuration has been devised in which a part of the fuel pipe is piped to the combustion chamber as the fuel evaporation pipe 19 and the fuel is heated by the combustion flame to be vaporized. According to this configuration, if the fuel is started and the combustion flame is formed, the fuel is vaporized well, and the rated heat generation capacity can be exhibited in a relatively short time.

However, according to this configuration, since the fuel evaporation pipe 19 is exposed to a combustion flame having a temperature of 1000 ° C. or higher, the fuel flowing inside is overheated and carbonized, and as shown in FIG. There is a problem that a problem occurs by blocking the fuel.

Further, as shown in FIG. 7, the public practical use S54-138137 is a combustion device in which the fuel supplied by the electromagnetic pump 103 is heated and vaporized by the vaporizer 110 and ejected to the burner 107 to be burned. A configuration is disclosed in which a residual heat pipe 108 is provided in the middle of the discharge side pipe 106 between the vaporizers 110, and the fuel is preheated by the exhaust gas after passing through the heat exchanger 117.

According to this configuration, the fuel is preheated with the exhaust gas as in the configuration of FIG. 5, so that a quick start-up of the system can be expected. Further, since the exhaust gas temperature after passing through the heat exchanger 117 is around 200 ° C., it is possible to prevent the above-mentioned problem that the fuel is overheated and carbonized. However, there is a problem that the residual heat tube 108 is not sufficiently heated at a temperature of about 200 ° C. and a good vaporized fuel cannot be produced.

Public practical use S54-138137

The present invention has been made in view of this point, and its main purpose is to be mounted on an automobile and used for various heating means such as vehicle interior heating. The warm-up time of the system is short and heat is generated quickly. The purpose of the present invention is to provide a compact combustion heater system that can demonstrate its capabilities and does not cause problems due to fuel carbonization in the fuel piping.

The invention according to claim 1 is the same via a burner top having a plurality of nozzles for blowing out the air-fuel mixture by mixing air and the vaporized fuel generated by vaporizing the liquid fuel with a fuel evaporation pipe to generate an air-fuel mixture. In a combustion type heater in which an air-fuel mixture is introduced into a combustion chamber and burned, and the combustion gas is guided to a heat exchanger provided downstream of the combustion chamber to heat the cooling water, the fuel evaporation pipe is placed on the outer peripheral wall surface of the combustion chamber. It is characterized in that it is arranged so as to be close to the burner top.

The portion close to the outer peripheral wall surface of the combustion chamber and close to the burner top, which is the configuration of claim 1, does not reach the fuel carbonization temperature of 400 ° C. to 500 ° C. and is close to the combustion flame 300. Since the temperature reaches around ° C., good vaporized fuel can be produced without carbonizing the fuel flowing through the fuel evaporation pipe 19.

The device according to claim 2 is characterized in that, in addition to the configuration of the device according to claim 1, a cooling water passage is formed in the outer wall surface of the combustion chamber.

According to the configuration of claim 2, since the cooling water passage is formed in the outer peripheral wall surface of the firing chamber near the fuel evaporation pipe 19, the outer peripheral wall surface of the firing chamber is maintained at an appropriate temperature, and the fuel evaporation pipe 19 It is possible to prevent overheating of the fuel flowing inside and prevent carbonization.

In the invention according to claim 3, in addition to the configuration of the invention according to claim 1 or 2, the liquid fuel in which the fuel evaporation pipe is heated by a combustion flame ejected from the injection port and flows inside the fuel evaporation pipe. It is characterized in that the length of the fuel evaporation pipe is adjusted so that the fuel reaches the vaporization temperature.

According to the configuration of claim 3, since the length of the fuel evaporation pipe is adjusted so that the liquid fuel flowing inside the fuel evaporation pipe reaches the vaporization temperature, good vaporized fuel can be produced.

According to the present invention, it is possible to provide a compact combustion type heater system which has a short warm-up time, can quickly exhibit heat generation ability, and does not cause a problem due to carbonization of fuel in a fuel pipe.

It is an external view of the small combustion type heater in one Embodiment of this invention. It is a vertical sectional view of the small combustion type heater in one Embodiment of this invention. It is a vertical cross-sectional view which mainly represented the fuel pipe and the fuel evaporation pipe of the upper part of the small combustion type heater in one Embodiment of this invention. It is a horizontal sectional view of the upper part of the combustion chamber of the small combustion type heater in one Embodiment of this invention. It is a horizontal sectional view of the upper part of a small combustion type heater combustion chamber of a conventional example. It is a vertical cross-sectional view near the fuel nozzle of the small combustion type heater of the conventional example. It is a figure showing the combustion apparatus according to the public practical use S54-138137. The comparison of the rising performance of the water heating amount of the developed product (small combustion type heater of the present invention) and the market product (small combustion type heater manufactured by another company) is shown.

1 Small combustion type heater 2 Blower 3 Combustion chamber head 4 Combustion chamber block 5 Heat exchanger holder 11 Air supply passage 12 Stirring chamber 13 Combustion chamber 14 Heat exchanger 15 Cooling water passage 16 Ventury 17 Fuel nozzle 19 Fuel evaporation pipe 20 Ignition heater 23 Burner top 24 Injection port 30 Exhaust passage 31 Volume 32 Combustion chamber wall 36 Cooling water inlet 37 Cooling water outlet

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments. Further, it can be appropriately changed as long as it does not deviate from the range in which the effect of the present invention is exhibited.

FIG. 1 is a diagram showing the appearance of a small combustion heater according to an embodiment of the present invention. Further, FIG. 2 is a vertical cross-sectional view of the small combustion type heater. Although the present compact combustion heater 1 is not required to have the current posture shown in the vehicle, the vertical direction and the horizontal direction are indicated based on the shown posture for convenience.

(Structure of the compact combustion heater of the present invention)
First, the configuration of the compact combustion heater of the present invention will be described with reference to FIGS. 1 to 4.
As shown in FIG. 1, air is supplied through the air supply passage 11 by the action of the blower 2. When the air supply passage 11 exits the blower 2, it is connected to the air supply passage formed in the combustion chamber head 3 as shown in FIG. 3, and the venturi 16 is formed at the terminal portion.

A fuel nozzle 17 is open in the venturi 16 part. As shown in FIG. 7, the end portion of the Venturi 16 is open to the stirring chamber 12 provided in the combustion chamber head 3. As shown in FIG. 3, 23 burner tops having a large number of nozzles 24 formed therein are arranged below the burner tops and are connected to the combustion chamber 13. The combustion chamber 13 is surrounded by a combustion chamber block 4, and a cooling water passage 15 is formed in the wall surface of the combustion chamber block 4.

A heat exchanger 14 is arranged in the lower part of the combustion chamber 13, and the periphery and the lower part are surrounded by a heat exchanger holder 5. The inside of the heat exchanger holder 5 is connected to the cooling water passage 15 of the combustion chamber block 4, and the inside is filled with cooling water. When combustion is performed in the combustion chamber 13 with this configuration, the burnt gas is introduced into the primary side passage configured in the heat exchanger 14, and the heat of the burned gas is transferred to the cooling water of the secondary side passage. .. At the lower part of the heat exchanger holder 5, a volume portion 31 for collecting the burnt gas that has passed through the heat exchanger 14 and an exhaust passage 30 for guiding the burnt gas to the exhaust system are provided. The cooling water passage 15 is provided with a cooling water inlet 36 in the heat exchanger holder 5 and a cooling water outlet 37 in the combustion chamber block 4.

(Operation of the small combustion heater of the present invention)
A certain amount of air is supplied to the air supply passage 11 by the operation of the blower 2. Air is guided to the Venturi 16 through the air supply passage 11, and a fuel nozzle 17 is opened in the Venturi 16. With this configuration, the mixture is formed while the fuel in the liquid state is atomized by the Venturi effect even at the time of starting when combustion is not performed.

Once the ignition heater 20 ignites the air-fuel mixture in the combustion chamber 13 and combustion is started, the fuel evaporation pipe 19 arranged in the combustion chamber is heated by the heat of the combustion flame as shown in FIG. 5, and the fuel evaporation pipe 19 is heated. The liquid fuel inside is vaporized. Therefore, in the steady state, air and vaporized fuel are mixed in the Venturi 16, and a good air-fuel mixture is supplied.

FIG. 4 is a view of the upper part (inlet portion) of the combustion chamber 13 as viewed from below. The fuel evaporation pipe 19 is arranged close to the combustion chamber wall 32 and the burner top 23. This is configured so that a part of the fuel pipe is arranged in the combustion chamber 13 as the fuel evaporation pipe 19. According to this configuration, the fuel evaporation pipe 19 is appropriately heated by the flame, and the liquid fuel flowing in the fuel evaporation pipe 19 is vaporized.

Since the vicinity of the burner top 23 hits the root portion of the combustion flame having a relatively low temperature, it is possible to prevent the fuel evaporation pipe 19 from directly receiving the heat of the combustion flame having a temperature of 1000 ° C. or higher. Therefore, it is possible to avoid overheating the liquid fuel flowing in the fuel evaporation pipe 19 and reaching the fuel carbonization temperature of 400 ° C. to 500 ° C.

Further, a cooling water passage 15 is provided inside the combustion chamber wall 32 in order to keep the combustion chamber wall temperature at an appropriate temperature, and this configuration can further prevent the fuel evaporation pipe 19 from overheating.

On the other hand, the fuel evaporation pipe 19 is configured to receive sufficient heat from the combustion flame to vaporize the liquid fuel flowing inside. Specifically, the calorific value Qe required to vaporize the liquid fuel at the flow rate required to exhibit the rated heating capacity is the mass flow rate M of the liquid fuel, the specific heat Cp, the latent heat of vaporization V, the boiling point Θb, and the initial fuel temperature. If it is Θi, it is defined as Qe = M × (Cp × (Θb−Θi) + V). On the other hand, the amount of heat Qs supplied to the fuel flowing inside the fuel evaporation pipe 19 is the surface temperature Θp of the fuel evaporation pipe 19, the thermal conductivity λ, the heat transfer rate h between the fuel evaporation pipe 19 and the fuel flowing inside the fuel evaporation pipe 19, and the fuel. Assuming that the temperature Θf, the length L of the fuel evaporation pipe, the outer diameter D, and the plate thickness T, it is defined as Qs = (Θp−Θf) × π × D × L × (1 / h + T / λ). Therefore, by determining the length L of the fuel evaporation pipe 19 so that Qs ≧ Qe, the length of the fuel evaporation pipe that can receive a sufficient amount of heat for vaporization from the combustion flame can be adjusted.

Since the fuel is vaporized by the heat of combustion in the combustion chamber, once ignited, the rated heat generation capacity can be quickly exhibited without requiring a long warm-up time. FIG. 8 shows an experimental comparison of the start-up performance of the small combustion heater (developed product) of the present invention and the small combustion heater (market product) manufactured by another company at the time of system start-up. FIG. 8 shows the rising performance of the heat generation performance (water heating amount).

As shown in FIG. 8, the small combustion type heater of the present invention reaches a steady state within 1 minute after starting and exhibits sufficient heat generation performance (water heating amount), whereas the market product is in a steady state. It takes a couple of minutes to reach it. Therefore, it can be seen that the compact combustion type heater of the present invention is excellent in that it exhibits heat generation performance more quickly in response to changes in the environment.

As the liquid fuel, gasoline, light oil, various alcohol fuels, kerosene and the like can also be applied.

Next, the air-fuel mixture flows into the stirring chamber 12, the air-fuel mixture is agitated, and then the air-fuel mixture is introduced into the combustion chamber 13 via the burner top 23. The burner top 23 includes a large number of regularly aligned nozzles 24. The arranged nozzles 24 are configured so that the flame generates a vortex in the combustion chamber. Further, the ignition heater 20 is arranged so as to protrude into the combustion chamber, and the ignition heater 20 is energized when the system is started to ignite the air-fuel mixture flowing into the combustion chamber 13, and thereafter the burner top 23 is ignited. As many flames as the number of nozzles 24 are generated in the combustion chamber 13 at the boundary.

The primary gas passage of the heat exchanger 14 arranged in the lower part of the combustion chamber 13 and the combustion chamber 13 communicate with each other, and the high-temperature burnt gas is introduced into the primary gas passage. On the other hand, the secondary cooling water passage of the heat exchanger 14 communicates with the cooling water passage 15 on the outer periphery of the heat exchanger, and the cooling water passage 15 on the outer periphery of the heat exchanger is also the cooling water passage on the wall surface of the combustion chamber 13. As shown in FIG. 2, the cooling water is configured to circulate between the cooling water inlet 36 provided in the heat exchanger holder 5 and the cooling water outlet 37 provided in the combustion chamber block 4. The cooling water in the cooling water passage on the wall surface of the combustion chamber 13 circulates while appropriately cooling the combustion chamber. With these configurations, heat is transferred from the burnt gas to the cooling water via the heat exchanger 14.

The primary gas passages of the heat exchanger 14 are gathered at the lower volume portion 31 and connected to the exhaust passage 30, and the burned gas is discharged to the exhaust passage 30.

Claims (3)

Air and vaporized fuel generated by vaporizing liquid fuel with a fuel evaporation pipe are mixed to generate an air-fuel mixture, and the air-fuel mixture is introduced into the combustion chamber via a burner top having a plurality of nozzles for blowing out the air-fuel mixture. In a combustion type heater that heats the cooling water by guiding this combustion gas to a heat exchanger installed downstream of the combustion chamber.
The fuel evaporation pipe is arranged so as to be close to the outer peripheral wall surface of the combustion chamber and close to the burner top.
Combustion type heater featuring. A cooling water passage is formed in the outer wall surface of the combustion chamber.
The combustion type heater according to claim 1. The length of the fuel evaporation pipe was adjusted so that the fuel evaporation pipe was heated by the combustion flame ejected from the injection port and the liquid fuel flowing inside the fuel evaporation pipe reached the vaporization temperature.
The combustion type heater according to claim 1 or 2.

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