JP2000054921A - Fuel burning heater for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel burning heater for an internal combustion engine that can eliminate the necessity of piping equipment to supply combustion air to the heater from the outside, and can increase a degree of freedom of fuel burning heater arrangement. SOLUTION: This fuel burning heater 17, is provided: with a piercing air duct 43a through which air is flowed to an engine body 3; an air inlet pipe 17b1 for introducing combustion air into a combustion chamber 17d of the fuel burning heater 17 from this piercing air duct; and an air discharge pipe 17 d2 for discharging combustion gas, which is generated in the combustion chamber 17d, from the combustion chamber 17d to the air duct 43a. Either an inlet port 43 a2 or an outlet port 43 a1 of the air duct 43a is connected to a fresh air inlet port 13b or a fresh air discharge port 13c of an air cleaner 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion type heater for an internal combustion engine, and more particularly, to a combustion type heater provided in an intake system of an internal combustion engine.
The present invention relates to a combustion-type heater suitable for promoting warm-up of an internal-combustion engine and improving performance of a heater for a vehicle compartment of a vehicle equipped with the internal-combustion engine by using exhaust gas emitted from the combustion-type heater.

[0002]

2. Description of the Related Art In cold weather, it is desired to promote warm-up of an internal combustion engine and to improve the performance of a heater for a vehicle compartment of a vehicle equipped with an internal combustion engine.

Therefore, a technique of providing a combustion type heater in an intake system of an internal combustion engine and using the combustion heat generated by the combustion type heater to promote warming up of the internal combustion engine and improve performance of a heater for a vehicle compartment has been proposed, for example, in actual technology. This is disclosed in Japanese Unexamined Patent Publication No. 62-99414.

[0004]

By the way, in order to operate the combustion type heater and generate a flame therein, piping equipment for connecting the combustion type heater and the intake system so that combustion air can be constantly flowed to the combustion type heater. Is required, and this plumbing equipment
A supply line for a combustion type heater which supplies combustion air to a combustion type heater main body by branching off from an intake main line constituting an intake system, and an exhaust tube for a combustion type heater for returning combustion gas emitted from the combustion type heater to the intake system. Consists of Therefore, in the conventional technology, a combustion-type heater having such piping equipment is attached to the intake system, so that the intake system becomes larger accordingly. In addition, since such a pipe that performs intake and exhaust to and from the combustion-type heater has a bypass-like path from the intake main pipe to the supply pipe for the combustion-type heater, the combustion-type heater, and the exhaust pipe for the combustion-type heater,
Complicates the intake system. In addition, places where such a bypass path can be installed in the intake system are naturally limited in a limited space of the vehicle. Therefore, the degree of freedom of installation of the combustion type heater is extremely low.

The combustion type heater of the present invention has been made in view of the above circumstances, and does not require piping equipment for supplying combustion air to the combustion type heater from the outside thereof. It is an object of the present invention to provide a combustion-type heater for an internal combustion engine that can increase the degree of freedom of the combustion.

[0006]

In order to solve the above problems, a combustion type heater for an internal combustion engine according to the present invention has the following configuration.

(1) When the internal combustion engine is in a predetermined operating state, the engine is operated to promote warming-up of the internal combustion engine and to improve the performance of a heater for a vehicle compartment of a vehicle equipped with the internal combustion engine. A combustion type heater for an internal combustion engine that takes in air for use and returns combustion gas to the intake passage, wherein a main body of the combustion type heater includes a through air passage that penetrates the main body and allows air to pass therethrough; An air introduction pipe for introducing combustion air into a combustion chamber of the combustion type heater, and an air discharge pipe for discharging combustion gas generated in the combustion chamber from the combustion chamber to the through air passage. The path is characterized by connecting its inlet or outlet to a fresh air inlet or fresh air outlet of the air cleaner.

Here, "when the internal combustion engine is in a predetermined operating state" refers to the amount of heat generated during the operation of the internal combustion engine or when the internal combustion engine is started, and the amount of heat generated by the internal combustion engine itself in cold or extremely cold conditions. (For example, when fuel consumption is low) and when the amount of heat received by the cooling water is low. And, when it is cold, the outside temperature is -10 ° C ~
When the temperature is around 15 ° C, when the temperature is extremely cold, the outside air temperature is -10 ° C.
It is when it is lower than.

The combustion type heater is a vaporization type combustion heater and has a structure in which the temperature of the engine cooling water increases while the engine cooling water circulates inside the heater by circulating the engine cooling water inside the heater. It is preferable that the warmed engine cooling water is used as a heat medium for a vehicle heater.

In the combustion type heater for an internal combustion engine according to the present invention, a through-air passage, an air introduction pipe for introducing combustion air from the through-air passage into a combustion chamber, and a combustion gas generated in the combustion chamber are provided in the main body. Is provided to the through-air passage, so that the combustion air sent to the combustion chamber of the combustion heater and the combustion gas from the combustion chamber enter and exit the through-air passage. In addition, since the through air passage, the air introduction pipe, and the air discharge pipe are both inside the combustion type heater, no air flows into and out of the combustion chamber between the combustion type heater and the outside. Therefore, when supplying combustion air or discharging combustion gas between the combustion type heater and the outside thereof, the piping equipment which has been required so far becomes unnecessary. Therefore, since there is no need to provide such a space, the size of the device can be reduced.

Further, since the inlet or outlet of the through air passage is connected to the fresh air inlet or fresh air outlet of the air cleaner, the combustion type heater to which the through air passage belongs can be connected to the air cleaner and its fresh air inlet or to the fresh air inlet. Integrated at the air outlet side. As described above, the arrangement of the combustion heater can be selected either on the fresh air inlet side or on the fresh air outlet side of the air cleaner, so that the degree of freedom of arrangement of the combustion heater is increased accordingly.

(2) In the above item (1), it is preferable that a connection point of the air introduction pipe with the through air path and a connection point of the air discharge pipe with the through air path are adjacent to each other.

Here, "adjacent" means that the distance between the two connection points is as small as possible so that the pressure loss that may occur when the two connection points are separated from each other is reduced as much as possible.
If the pressure loss at both connection points is large, the flow of air flowing through the path of the air inlet pipe-the combustion chamber of the combustion type heater-the air exhaust pipe will be faster, and a phenomenon similar to that when it is difficult to light a lighter or match in strong winds Since it is difficult to cause ignition in the combustion chamber, the pressure loss at both connection points is preferably as low as possible.

Since the combustion type heater for an internal combustion engine according to this aspect has such a configuration, ignition in the combustion chamber can be facilitated. (3) In the above item (2), the connection point of the air discharge pipe with the through air path is located downstream of the connection point of the air introduction pipe with the through air path in the through air path. Is preferred.

Since the combustion type heater for an internal combustion engine according to this aspect has such a configuration, the connection point of the air introduction pipe to the through air passage is closer to the connection point of the air discharge pipe to the through air passage. Is also located upstream. Therefore, it is possible to prevent the combustion gas generated in the combustion chamber coming out of the connection point between the air discharge pipe and the through air path into the through air path from flowing back to the air introduction pipe on the upstream side in the through air path.

(4) In any one of the above items (1) to (3), an air introduction forcibly introducing air into the air introduction tube is provided at a connection point of the air introduction tube with the through air passage. Forcing means may be provided.

Since the combustion type heater for an internal combustion engine according to this aspect has such a configuration, the combustion condition of the combustion type heater can be optimized by properly adjusting the air introduction forcing means. (5) In the above item (4), the air introduction forcing means is preferably a blower fan.

Here, it is preferable that the rotation speed of the blower fan be controlled by an engine electronic control unit ECU that controls the combustion state of the combustion type heater.

Since the combustion type heater for an internal combustion engine according to this aspect has such a configuration, if the blower fan is controlled by the ECU, the ECU controls the rotation of the blower fan in addition to other factors. Therefore, the combustion condition of the combustion heater can be optimized.

(6) In the above item (5), a recess for mounting a combustion type heater is provided in a portion including a fresh air inlet or a portion including a fresh air outlet of the air cleaner. Preferably, the combustion heater body is formed in a shape that conforms to the shape and shape.

In the combustion type heater for an internal combustion engine according to this aspect, the combustion type heater can be fitted into a combustion type heater mounting recess provided in an air cleaner. In this case, the combustion heater matches the size and shape of the combustion heater mounting recess of the air cleaner, so that the combustion heater becomes a part of the air cleaner and is integrated. For this reason, it is also preferable in terms of design. Further, even when only the combustion type heater breaks down, the alternative combustion type heater can be replaced with a cartridge type, so that it is possible to respond quickly.

(7) In the above item (6), it is preferable that the combustion-type heater main body has a rectangular parallelepiped shape or a cubic shape.

[0023]

Embodiments of the present invention will be described below with reference to the accompanying drawings. <Embodiment> A first embodiment of the present invention will be described with reference to FIGS.

The engine 1 as an internal combustion engine is of a water-cooled type, and has an engine body 3 having a water jacket (not shown) through which cooling water circulates, and air required for combustion in a plurality of cylinders (not shown) of the engine body 3. It has an intake device 5 for feeding in, an exhaust device 7 for releasing exhaust gas after the air-fuel mixture has burned in the cylinder into the atmosphere, and a vehicle interior heater 9 for warming the interior of a vehicle on which the engine 1 is mounted.

The intake device 5 uses the air cleaner 13 as a starting end of the intake device 5. Further, a compressor 15a, an intercooler 19, and an intake manifold 21 of a turbocharger 15, which is an intake system structure, are provided between the air cleaner 13 and an intake port (not shown) of the engine body 3, which is the end of the intake device 5. .

These intake system structures are arranged at appropriate intervals in the intake pipe 23. The intake pipe 23 is located downstream of the compressor 15a, and is forcibly pushed by the compressor 15a to the outside air entering the intake device 5 to be in a pressurized state. It can be roughly divided into an upstream pipe 25 located on the upstream side.

In FIG. 1, the downstream pipe 27 is a pipe connecting the compressor 15a and the intake manifold 21. In addition, an intercooler 19 is installed at the center of the downstream pipe 27.

On the other hand, the exhaust device 7 has an exhaust port (not shown) of the engine body 3 as a starting end of the exhaust device 7 and a portion between the exhaust port 7 and a muffler 41 at the end of the exhaust device 7, the exhaust manifold 37 and the turbine of the turbocharger 15. 15b and the exhaust catalyst 39 are provided on the exhaust pipe 42. Since these are well known and do not directly relate to the present invention, the description will be omitted.

The outside air a1 entering the upstream pipe 25 from the air cleaner 13 is fresh air for the exhaust of the engine 1. The air flowing through the exhaust device 7 is indicated by reference numeral a3 as the exhaust gas of the engine 1.

As can be seen from FIGS. 2 and 3, the air cleaner 13 has a rectangular parallelepiped shape in this embodiment, and a filter 13a is installed horizontally at the center in the vertical direction. Further, a fresh air inlet 13b and a fresh air outlet 13c are provided at one lower corner and one upper corner of the air cleaner 13 with the filter 13a as a boundary. One lower corner where the fresh air introduction port 13b is located is a stepped concave portion 13d as cut out in a rectangular parallelepiped shape. The stepped recesses are provided during operation or after starting the engine 1 when the engine 1 is cold or extremely cold, and when the engine 1 is cold.
When the calorific value is small (for example, when fuel consumption is small)
Further, a combustion type heater 17 which operates when the amount of heat received by the cooling water is small to promote warming-up of the engine 1 and improve the performance of the vehicle interior heater 9 of a vehicle equipped with an internal combustion engine is attached.
Therefore, the recess 13d is hereinafter referred to as a combustion heater mounting recess 13d.

Next, the structure of the combustion type heater 17 is schematically shown in FIG. The overall shape and size of the combustion heater 17 match the shape and size of the combustion heater mounting recess 13d. In this embodiment, the combustion type heater 17 has a rectangular parallelepiped shape.

The combustion heater 17 is a main body of the combustion heater 17 and has a case body 4 representing the outer shape of the combustion heater 17.
A combustion type heater 17 is formed in 3 and includes a plurality of constituent members which will be sequentially described below.

The combustion type heater 17 has a through air passage 43a which penetrates the case body 43 in the direction of the small edge thereof. The through air passage 43a is a main pipe for introducing combustion air to the combustion heater 17 and discharging combustion gas from the combustion heater 17 through the through air passage 43a. The outlet 43a1 of the through air passage 43a is connected to the fresh air inlet 13b of the air cleaner 13, and the through air passage 43a introduces outside air into the air cleaner 13.
“a” also functions as an outside air introduction pipe to the air cleaner. In other words, the through-air passage 43a also functions as an intake passage that circulates air from outside to the engine 1.

The combustion heater 17 is connected to the water jacket of the engine body 3 (see FIG. 1). Therefore, the combustion heater 17 is provided with cooling water through which cooling water from the water jacket passes. It has a passage 17a. The cooling water W flowing through the cooling water passage 17a is supplied to a combustion chamber 17d inside the combustion type heater 17 where a flame is generated.
Around the combustion chamber, during which the combustion chamber 17d
Warms up from the heat. The combustion chamber 17d includes a combustion tube 17b that emits a flame, and a cylindrical partition 17c that covers the combustion tube 17b to prevent the flame from leaking to the outside. The combustion chamber 17d is defined in the partition 17c by covering the combustion cylinder 17b with the partition 17c. The partition wall 17c is also covered by the case body 43 of the combustion type heater 17, and a space is provided between the two. By providing this interval, the cooling water passage 17a is formed between the inner surface of the case body 43 and the outer surface of the partition wall 17c.

The combustion chamber 17d is connected to the through air passage 4
It has an air introduction pipe 17d1 and an air discharge pipe 17d2 respectively connected to 3a. The air introduction pipe 17d1 and the air discharge pipe 17d2 are pipes for introducing combustion air into the combustion chamber 17d and pipes for discharging combustion gas generated in the combustion chamber 17d from the combustion chamber 17d.

Air introduction pipe 17 in through air passage 43a
d1 and the connection point 17 of the air discharge pipe 17d2
d1 'and 17d2' are adjacent, and connection point 17d2 'is on the downstream side. Here, “adjacent” means both connection points 1
This means that the distance between the two connection points is made as small as possible in order to reduce as much as possible the pressure loss that can occur when 7d1 'and 17d2' are separated. If the pressure loss at both connection points is large, the air introduction pipe 17d1
The air flow flowing through the path of the d-air discharge pipe 17d2 becomes faster, and a similar phenomenon occurs when a lighter or a match is hardly ignited in a strong wind, so that it becomes difficult to ignite in the combustion chamber 17d. This is because the pressure loss is preferably as low as possible.

From the through air passage 43a to the air introduction pipe 17d1
Outside air a2 flowing into the combustion chamber 17d via the air introduction pipe 17d1 is provided to the combustion chamber and becomes combustion gas. This combustion gas then returns to the through air passage 43a via the air discharge pipe 17d2. Then, there, the through air passage 43a is mixed with the outside air a2 flowing without branching into the air introduction pipe 17d1 to become the air a1, and finally enters the air cleaner 13 through the fresh air inlet 13b of the air cleaner 13.

The outside air returning to the through air passage 43a via the air discharge pipe 17d2 has heat because it is the exhaust gas discharged from the combustion heater 17. Until the heated outside air is discharged from the combustion heater 17 to the through air passage 43a as the air a1, the heat of the air a1 is transferred to the cooling water flowing through the cooling water passage 17a through the partition wall 17c. It is transmitted to W and warms this.
Therefore, the combustion chamber 17d is also a heat exchange passage.

The combustion cylinder 17b is provided with a fuel supply pipe 17e connected to a fuel pump (not shown), and receives the pump pressure of the fuel pump therefrom to supply combustion fuel to the combustion cylinder 17b. The supplied combustion fuel is vaporized in the combustion heater 17 to become vaporized fuel, and the vaporized fuel is ignited by an ignition source (not shown).

Next, referring to FIG.
The circulation of the cooling water for 7a will be described. The cooling water passage 17a has a cooling water inlet 17a1 connected to the water jacket of the engine body 3, and a cooling water outlet 17a2 connected to the vehicle interior heater 9.

A water pipe W1 is interposed between the cooling water inlet 17a1 and the engine body 3, and a water pipe W2 is connected between the cooling water outlet 17a2 and the vehicle interior heater 9.
The combustion heater 17 is connected to the water jacket of the engine body 3 and the vehicle heater 9 via the water pipes W1 and W2. Further, the vehicle interior heater 9 and the engine body 3 are also connected via a water pipe W3.

Accordingly, the cooling water in the water jacket of the engine body 3 flows in the following order: (1) from the cooling water inlet 17a1 to the combustion heater 17 via the water pipe W1, where it is heated. (2) The heated cooling water is supplied to the cooling water discharge port 17a2 of the combustion type heater 17.
To the vehicle interior heater 9 via the water conduit W2. (3)
Then, after the cooling water is subjected to heat exchange by the vehicle interior heater 9 and its temperature is lowered, it returns to the water jacket via the water pipe W3.

As described above, the cooling water is supplied to the engine body 3 through the water pipe W1, the water pipe W2, and the water pipe W3.
It circulates between the combustion heater 17 and the vehicle interior heater 9. Further, inside the combustion chamber main body 43, a blower fan 45 as an air introduction forcing means and an engine electronic control unit (E
Central processing control unit (CP) belonging to
U).

The blower fan 45 is located in the through air passage 43a at a position facing the connection 17d1 'of the air introduction pipe 17d1 with the through air passage 43a. The ECU 46
Various sensors such as an outside air temperature sensor, a combustion gas temperature sensor, and a rotation speed sensor (not shown) are electrically connected to the blower fan 45 and the fuel pump (not shown). Then, the CPU of the combustion type heater 17 operates according to each parameter output from each of these sensors, and thereby the combustion state of the combustion type heater 17 is controlled. In other words, the momentum, size, temperature and the like of the flame of the combustion type heater 17 are controlled, and the exhaust temperature of the combustion type heater 17 is controlled by this control. <Modification> A modification will be described with reference to FIGS.

In this modified example, the mounting position of the combustion type heater 17 in the air cleaner 13 is on the side of the fresh air discharge port 13c of the air cleaner 13, so that the inlet 43a2 of the through air passage 43a is connected to the fresh air discharge port 13c of the air cleaner 13. This is different from the above case. That is,
A combustion heater mounting recess 13d is formed in one upper corner of the air cleaner 13 where the fresh air outlet 13c is located, and the combustion heater 17 is mounted therein. The other parts are exactly the same. Note that the same parts are denoted by the same reference numerals, and description thereof will be omitted. <Effects of Embodiment> In the engine 1, in the case body 43 of the combustion type heater 17, a through air passage 43a, an air introduction pipe 17d1 for introducing combustion air from the through air passage 43a to the combustion chamber 17d, An air discharge pipe 17d2 for discharging combustion gas generated in the combustion chamber 17d to the through air passage 43a is provided. Therefore, the combustion air sent to the combustion chamber 17d of the combustion heater 17 and the combustion gas exiting from the combustion chamber 17d enter and exit the through-air passage 43a. Moreover,
Since both the through air passage 43a, the air introduction pipe 17d1, and the air discharge pipe 17d2 are inside the combustion type heater 17, air does not enter or leave the combustion chamber 17d with the outside of the combustion type heater 17 at all. Absent. Therefore, there is no need for any piping equipment required to supply combustion air or discharge combustion gas between the combustion heater 17 and the outside. Therefore, no space is required, and the size of the apparatus is reduced.

The outlet 43a1 or the inlet 43a2 of the through air passage 43a is connected to the fresh air inlet 13 of the air cleaner 13.
b or the fresh air outlet 13c, the combustion type heater 17 is connected to the fresh air inlet 13b or the fresh air outlet 13c of the air cleaner 13 through the through air passage 43a, so that the combustion is started. The heater 17 is integrated with the air cleaner 13 on the side of the fresh air inlet 13b or on the side of the fresh air outlet 13c. Therefore, the location of the combustion type heater 17 can be selected from either of them, so that the degree of freedom of arrangement of the combustion type heater 17 is increased accordingly.

Further, since the combustion gas of the combustion type heater 17 is cooled by being mixed with the outside air, it is possible to prevent heat damage to the intake system structure. Furthermore, the connection point 17d1 'of the air introduction pipe 17d1 with the through air passage 43a and the air discharge pipe 1
Since the connecting portion 17d2 'of the 7d2 with the through air passage 43a is adjacent, the pressure loss in the combustion chamber when compared at both connecting portions is small, so that the combustion type heater 17 can be easily ignited.

The connection points 17d1 'and 17d2'
Since the connection point 17d2 'is located downstream in the through air passage 43, the combustion gas flowing out of the connection point 17d2' into the through air passage 43 is prevented from flowing back to the upstream air introduction pipe 17d1.

Further, since the blower fan 45 is provided at the connection point 17d1 ', the rotational speed of the blower fan 45 is controlled by the ECU 4.
If the adjustment is properly made according to 6, the combustion condition of the combustion heater can be optimized.

Further, since the outer shape of the combustion heater 17 matches the size and shape of the combustion heater mounting recess 13d of the air cleaner 13, the combustion heater 17 becomes a part of the air cleaner 13 and is integrated. It is also preferable in terms of design. Further, even when only the combustion type heater 17 fails, an alternative combustion type heater can be substituted, so that it is possible to respond quickly.

[0051]

As described above, according to the present invention, there is no need for a piping system for supplying and discharging combustion air to and from the outside of the combustion type heater, and the degree of freedom in arranging the combustion type heater is increased. Can also.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an embodiment to which a combustion heater for an internal combustion engine according to the present invention is applied.

FIG. 2 is a longitudinal sectional view of an air cleaner.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a schematic sectional view of a combustion type heater.

FIG. 5 is a diagram showing a modification example corresponding to FIG. 1;

6 is a view corresponding to FIG. 2 according to FIG. 5;

FIG. 7 is a sectional view taken along line VII-VII of FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine) 3 ... Engine main body 5 ... Intake device 7 ... Exhaust device 9 ... Heater for vehicle interior 13 ... Air cleaner 13a ... Filter 13b ... Fresh air inlet of air cleaner 13c ... Fresh air outlet of air cleaner 13d ... Combustion Heater mounting recess 15 Turbocharger 15a Compressor 15b Turbine 17 Combustion heater 17a for internal combustion engine Cooling water passage 17a1 Cooling water inlet 17a2 Cooling water outlet 17b Combustion cylinder 17c Cylindrical partition wall 17d: combustion chamber 17d1: air introduction pipe 17d2: air discharge pipe 17d1 ': air introduction pipe 17 in the through air passage 43a
Connection point of d1 17d2 '... air discharge pipe 17 in through air passage 43a
Connection point d2 17e Fuel supply pipe 19 Intercooler 21 Intake manifold 23 Intake pipe 25 Upstream connection pipe 27 Downstream connection pipe 37 Exhaust manifold 39 Exhaust catalyst 41 Muffler 42 Exhaust pipe 43 Case body (main body of combustion type heater) 43a: through air passage (intake passage) 43a1, outlet of through air passage 43a2: inlet of through air passage 43a 45: blower fan (air introduction forcing means) 46: ECU W1: water pipe Path W2: Water pipe W3: Water pipe a1 ... Outside air entering the upstream pipe 25 from the air cleaner 13 a2 ... Outside air flowing from the through air path 43a to the air introduction pipe 17d1

Claims (7)

[Claims] An internal combustion engine is operated in a predetermined operation state to promote warm-up of the internal combustion engine and to improve the performance of a heater for a vehicle compartment of a vehicle equipped with the internal combustion engine. In a combustion type heater for an internal combustion engine that takes in air and returns combustion gas to the intake passage, a main body of the combustion type heater includes a through air passage penetrating the main body and passing air, An air introduction pipe for introducing combustion air into a combustion chamber of the combustion heater; and an air discharge pipe for discharging combustion gas generated in the combustion chamber from the combustion chamber to the through air path. A combustion type heater for an internal combustion engine, characterized in that its inlet or outlet is connected to a fresh air inlet or a fresh air outlet of an air cleaner. 2. The internal combustion engine according to claim 1, wherein a connection point of the air introduction pipe with the through air path and a connection point of the air discharge pipe with the through air path are adjacent to each other. For combustion type heater. 3. A connection point of the air discharge pipe with the through air path is located downstream of a connection point of the air introduction pipe with the through air path in the through air path. Item 3. A combustion-type heater for an internal combustion engine according to item 3. 4. An air introduction forcing means for forcibly introducing air into the air introduction pipe is provided at a connection point of the air introduction pipe with the through air passage.
An internal combustion engine having the combustion heater according to claim 3. 5. The combustion type heater for an internal combustion engine according to claim 4, wherein said air introduction forcing means is a blower fan. 6. A combustion heater mounting recess is provided at a fresh air inlet or a fresh air outlet of the air cleaner, and the combustion heater main body is formed in a shape matching the size and shape of the combustion heater mounting recess. The combustion heater for an internal combustion engine according to claim 5, wherein the heater is formed. 7. The combustion-type heater for an internal combustion engine according to claim 6, wherein the combustion-type heater body has a rectangular parallelepiped shape or a cubic shape.