JP2000265911A - Internal combustion engine having combustion heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent contraflow of combustion gas of a combustion heater inside the heater. SOLUTION: A part of intake boosted by a compressor 15a of a turbocharger 15 is supplied to a combustion heater 91 through an air supply pipe as combusting air. Combustion gas from the combustion heater 91 is discharged to an exhaust passage 42 on an upstream side of an intake passage 14 or a catalytic converter 39 through a combustion gas discharge pipe 73 or a branch pipe 84. A check valve 96 is arranged between a rotary fan 90 of the combustion heater 91 and a combustion chamber 48. The check valve 96 allows the combusting gas (combusting air) to flow from the side of the rotary fan 90 into the combustion chamber 48, and prevents the gas (combustion air) from flowing in the opposite direction. When the air supply pipe 71 is broken and communicated with the atmosphere, the check valve 96 is closed for preventing the combustion gas from flowing from the combustion chamber 48 to the rotary fan 90.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine having a combustion heater, and more particularly, to improving the low temperature startability of an internal combustion engine by increasing the temperature of engine-related elements such as cooling water, intake air or exhaust gas, and warming up the engine. The present invention relates to an internal combustion engine having a combustion-type heater for promoting the performance of a vehicle interior heating device, promoting the warm-up of an exhaust gas purification device, and the like.

[0002]

2. Description of the Related Art Diesel engines, lean burn engines, and other lean-burn engines mounted on vehicles such as automobiles generate less heat than ordinary gasoline engines. Therefore, a lean-burn engine is often provided with a combustion heater for the purpose of, for example, promoting warm-up in cold weather and improving the performance of a vehicle interior heating device.

[0003] The basic principle of the combustion type heater is that heat of combustion gas generated when fuel is burned in a combustion chamber of the combustion type heater is transferred to a heat medium (for example,
The heat medium is absorbed by water and heated, and the heated heat medium is sent to a water jacket of the engine body, a heater core for heating the vehicle compartment, and other necessary parts, thereby raising the temperature of these necessary parts.

Japanese Patent Laid-Open Publication No. Sho 60-78819 discloses an internal combustion engine having a conventional combustion type heater. In the technique described in this publication, a part of intake air flowing through an intake pipe of an internal combustion engine is introduced as combustion air for a combustion heater from an air intake of a combustion heater, and the introduced combustion air is supplied to a combustion fan by a blowing fan. The fuel is pumped into the combustion chamber of the heater, mixed with the fuel supplied to the combustion chamber, and the combustion gas generated by burning the mixture is discharged from the combustion gas outlet to the exhaust passage upstream of the catalytic converter, and the combustion gas is discharged to the engine. It is purified by a catalytic converter together with the exhaust gas discharged from the fuel cell. The internal combustion engine described in this publication does not have a supercharger. Although the purpose of introducing the combustion gas into the exhaust passage is purifying the combustion gas in the above-mentioned publication, the purpose of introducing the combustion gas into the exhaust passage is not limited to this. is there.

[0005]

When the internal combustion engine is provided with a supercharger, the combustion gas of the combustion heater can flow through the exhaust passage even when the exhaust gas pressure increases during operation of the engine. Next, it is conceivable to introduce the intake air pressurized by the supercharger as combustion air for a combustion type heater. In such a case, the following problem may be newly generated.

[0006] If the supercharger performs supercharging while the combustion gas of the combustion heater is being introduced into the exhaust passage, the intake air is supplied from the intake pipe to the combustion heater as combustion air due to an unexpected situation. When the air introduction pipe to be introduced is broken or the connection part is disconnected and the parts are opened to the atmosphere, the exhaust gas pressure in the exhaust passage becomes higher. Backflow of the combustion gas may occur toward the side, and the resin parts, wiring, and the like of the blower fan may be burned out, making the fan unusable.

For the purpose of warming up the engine, the combustion gas of the combustion heater may be returned to the intake passage downstream of the combustion air outlet in the intake passage.
Also in this case, if the air introduction pipe is damaged or the connection part is disconnected due to an unexpected situation, the same problem as described above may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and an object of the present invention is to solve a problem in that an air introduction pipe for introducing combustion air for a combustion heater from an intake passage is broken. It is an object of the present invention to provide an internal combustion engine having a combustion-type heater that can prevent damage to the combustion-type heater even if an unexpected situation such as dropping or a disconnection occurs.

[0009]

The present invention has the following features to attain the object mentioned above. The present invention introduces combustion air from an intake passage of an internal combustion engine and mixes it with fuel,
In an internal combustion engine having a combustion-type heater that heats an engine-related element using heat of combustion gas generated by burning the air-fuel mixture in a combustion chamber, a supercharger that boosts intake air of the intake passage, An air supply passage for introducing intake air pressurized by the supercharger as the combustion air, a combustion gas discharge passage for bypassing a cylinder of the internal combustion engine and introducing the combustion gas to an exhaust passage of the internal combustion engine, and Blowing means provided between a supply passage and the combustion chamber for introducing combustion air introduced from the air supply passage into the combustion chamber and introducing combustion gas generated in the combustion chamber into the combustion gas discharge passage. And a communication blocking means provided between the blowing means and the combustion chamber and capable of permitting and blocking the flow of gas therebetween.

[0010] In this internal combustion engine, normally, the communication shut-off means operates so as to allow gas (combustion air) to flow from the blowing means toward the combustion chamber. The introduced combustion air can be introduced into the combustion chamber, and the combustion gas generated by burning the air-fuel mixture in the combustion chamber can be introduced into the combustion gas discharge passage.

When a condition in which a backflow of gas can occur in the combustion type heater due to an unexpected situation such as breakage of the air supply path is satisfied, the communication cutoff means sets the gas between the blowing means and the combustion chamber. It operates to block the flow of (combustion gas). Thereby, it is possible to prevent the combustion gas from flowing back from the combustion chamber to the blowing means in the combustion type heater.

The engine-related elements include intake air, exhaust gas, engine cooling water, an internal combustion engine body for introducing combustion gas of a combustion heater into the intake air, and exhaust gas purifying means (D) provided in an exhaust passage.
PF and catalyst). Further, the blowing means can be constituted by a rotating fan driven by an electric motor.

The communication shut-off means is constituted by a check valve which permits gas to flow from the blower to the combustion chamber and prevents gas from flowing from the combustion chamber to the blower. be able to. Alternatively, communication is made from a pressure detecting means for detecting which of the pressure at the outlet of the blowing means or the pressure in the combustion chamber is larger, and an on-off valve for opening and closing a gas passage between the blowing means and the combustion chamber. A shut-off means may be configured to control the on-off valve to be closed when the pressure detection means determines that the pressure at the outlet of the blowing means is higher than the pressure in the combustion chamber.

In the internal combustion engine having the combustion type heater according to the present invention, the combustion gas is supplied to the intake passage and the combustion gas discharge passage downstream of the connection point with the air supply passage. The connection can be made via a combustion gas path switching means that can be selectively switched to which one to introduce. With this configuration, the path of the combustion gas can be switched by the combustion gas path switching means, and by the switching, the combustion gas is introduced into the intake passage to raise the temperature of an engine-related element of the intake system, or the combustion gas is transferred to the exhaust passage. To raise the temperature of engine-related elements of the exhaust system.

[0015]

1 to 3 show an embodiment of an internal combustion engine having a combustion heater according to the present invention.
This will be described with reference to the drawings.

The engine 1 as an internal combustion engine is a diesel engine or a gasoline direct injection lean burn engine. As shown schematically in FIG. 1, the engine 1 includes an engine body 3 having a water jacket (not shown) containing engine cooling water, and air required for combustion in a plurality of cylinders (not shown) of the engine body 3. An air-intake device 5 to be fed and a mixture of air sent to the cylinder via the air-intake device 5 and engine fuel injected and supplied into the cylinder are burned in a combustion chamber, and then exhaust gas discharged from the cylinder is released into the atmosphere. Exhaust device 7, an EGR device 8 as an exhaust recirculation device for suppressing the generation of nitrogen oxides by recirculating exhaust gas from the exhaust device 7 to the intake device 5, and the engine 1.
Separately, a combustion-type heater 91 that burns fuel and raises the temperature of engine-related elements by the heat of combustion gas generated at that time, a heater core 10 that is a vehicle interior heating device that raises the indoor temperature of a vehicle equipped with an engine, and an entire engine And an ECU 11 which is an engine control device for controlling the ECU.

The intake device 5 has an intake passage 14 which starts with an air cleaner 13 for filtering outside air and ends with an intake port (not shown) of the engine body 3. Intake passage 1
4, a compressor 1 of a turbocharger (supercharger) 15 is provided between the air cleaner 13 and the intake port.
5a, an intercooler 1 for cooling the intake air temperature which has been raised by the compression heat generated when the compressor 15a is operated.
9. Intake manifolds 22 as suction branch pipes are sequentially arranged. An intake throttle valve 51 for controlling the amount of intake air flowing through the intake passage 14 is provided between the intercooler 19 and the intake manifold 22. The combustion heater 91 is attached between the intercooler 19 and the intake throttle valve 51 in the intake passage 14.

The exhaust device 7 has an exhaust passage 42 starting from an exhaust port (not shown) of the engine body 3 and terminating at a muffler (not shown). In the exhaust passage 42, an exhaust manifold 28 serving as an exhaust branch pipe, a turbine 15b of the turbocharger 15, and a catalytic converter 39 serving as an exhaust gas purifying device are sequentially arranged between the exhaust port and the muffler. Examples of the catalyst accommodated in the catalytic converter 39 include a selective reduction type NOx catalyst, a storage reduction type NOx catalyst, and a DPF carrying an oxidation catalyst.

The EGR device 8 connects the intake passage 14 and the exhaust passage 42, bypasses the engine body 3, and returns the exhaust gas discharged from the exhaust port toward the intake side.
It has a GR passage 81 and an EGR valve 30 that controls the amount of exhaust gas flowing through the EGR passage 81.

The combustion type heater 91 introduces a combustion gas generated by burning the same fuel as the fuel used in the engine 1 into the intake passage 14 and flows through the intake device 5 using heat of the combustion gas. It is a heater that can raise the temperature of the intake air. The intake air whose temperature has been increased by the combustion heater 91 flows through the intake passage 14 toward the cylinder while containing combustion gas.

The combustion type heater 91 warms the engine cooling water by the heat of the combustion gas. The heated engine cooling water is required to raise the temperature of the heater core 10 and the engine body 3. Then, the temperature is raised at the required temperature-raising portion (only the heater core 10 and the engine body 3 are shown as the temperature-raising required portion in the drawing). The engine 1 is provided with a heat medium circulation path W so that the engine cooling water warmed by the combustion type heater 91 can be sent to the above-mentioned required temperature rising point.

The heat medium circulation path W connects the engine main body 3 with the combustion type heater 91, and a cooling water introduction path W 1 for leading the engine cooling water from the water jacket of the engine main body 3 to the combustion type heater 91, and a combustion type heater 91. A cooling water discharge passage W2 for guiding the engine cooling water heated by the heater core 10 to the heater core 10, and a cooling water discharge passage W3 for returning the engine cooling water flowing out of the heater core 10 to the water jacket of the engine body 3. Also, an electric water pump 5 is provided in the cooling water introduction passage W1.
0 is provided, and in addition to the circulation of the cooling water by a water pump built in the engine (not shown), the operation of the electric water pump 50 promotes the circulation of the engine cooling water in the heat medium circulation path W. .

Here, a specific configuration of the combustion type heater 91 will be described with reference to FIGS. The combustion type heater 91 has therein a heater internal cooling water passage 37 which is connected to the cooling water introduction passage W1 and the cooling water discharge passage W2 and is a part of the heat medium circulation passage W.

The heater internal cooling water passage 37 has a cooling water inlet 37a connected to the cooling water inlet W1 and a cooling water outlet 37b connected to the cooling water outlet W2. The heater internal cooling water passage 37 is formed so as to circulate around the combustion chamber 48 of the combustion type heater 91.

The combustion chamber 48 includes a combustion cylinder 40 as a combustion source for generating the flame F, and a cup-shaped partition wall 41 that covers the combustion cylinder 40 to prevent the flame F from leaking to the outside.
Consists of By covering the combustion cylinder 40 with the partition wall 41,
A combustion chamber 48 is defined within partition 41. The partition wall 41 is also covered with the outer wall 43 of the combustion type heater 91.

An annular gap is provided between the partition wall 41 and the outer wall 43, and this gap functions as the heater internal cooling water passage 37. The engine cooling water receives heat from the combustion chamber 48 while the engine cooling water flows in the heater internal cooling water passage 37. In other words, the engine cooling water exchanges heat with the hot combustion gas in the combustion chamber 48 to increase the temperature.

Further, the combustion chamber 48 has an air circulation port through which air enters and exits the combustion chamber 48. That is, the combustion chamber 48 has, as air circulation ports, an air supply port 62 for introducing combustion air into the combustion chamber 48 and combustion gas discharge ports 63 and 65 for discharging combustion gas from the combustion chamber 48. The air supply port 62 is located on the side opposite to the side where the flame F exits from the combustion tube 40 in the combustion chamber 48, and the combustion gas discharge port 63 is provided near the base end of the combustion tube 40 in the combustion chamber 48. is there.

The combustion gas discharge port 65 is located on the side where the flame F exits from the combustion tube 40, and faces the flame F,
1 and the outer wall 43. The combustion gas discharge ports 63 and 65 are connected via a connection pipe 74 extending parallel to the longitudinal direction of the combustion type heater 91. The air supply port 62 and the combustion gas discharge ports 63, 65
Are all connected to the intake passage 14. That is, the air supply port 62 communicates with the intake path 14 via an air supply pipe (air supply path) 71 that supplies combustion air from the intake path 14 to the combustion type heater 91, and the combustion gas discharge port 6
Reference numerals 3 and 65 denote a connection pipe 74 and a combustion gas discharge pipe 73 for discharging combustion gas from the combustion heater 91 to the intake passage 14.
Through the intake passage 14.

The connection point C1 between the air supply pipe 71 and the intake passage 14 and the connection point C2 between the combustion gas discharge pipe 73 and the intake passage 14 are close to each other, and the connection point C2 is larger than C1. Downstream. In addition, connection points C1 and C2
Are located upstream of the intake throttle valve 51 and downstream of the intercooler 19.

The combustion gas discharge pipe 73 has a valve device 78 for controlling the opening and closing of the combustion gas discharge port 65, and is connected to the combustion heater 91 via the valve device 78.
The valve device 78 has a valve chamber 79 having a valve body 80 for opening and closing the combustion gas discharge port 65 therein. The valve chamber 79 has two openings 79a and 79b.
Reference numerals a and 79b communicate with the combustion gas discharge port 65 and the combustion gas discharge pipe 73, respectively.

The valve device 78 has an actuator 82 for driving a valve element 80. When the valve element 80 is actuated by the actuator 82, the opening 79a is opened and closed, whereby the combustion gas discharge port 65 is opened and closed.

A three-way switching valve (combustion gas path switching means) 86 having three ports (first, second, and third ports) is attached in the middle of the combustion gas discharge pipe 73. A first port of the three-way switching valve 86 is connected to a combustion gas discharge pipe 73 connected to the valve device 78, a second port is connected to the combustion gas discharge pipe 73 connected to the intake passage 14, and a third port bypasses the engine body 3. (Ie, bypasses the cylinder of the engine body 3), and the branch pipe 84 is connected to a connection point C3 in the exhaust passage 42 near the upstream side of the catalytic converter 39.

The three-way switching valve 86 supplies the combustion gas to the intake passage 1
This is a switching valve that selectively switches between flowing toward the pipe 4 and flowing toward the branch pipe 84. The operation of the three-way switching valve 86 determines whether the combustion gas is introduced into the intake passage 14 or the exhaust passage 42.

On the other hand, a fuel introduction passage 88 for introducing fuel from the outside to the combustion cylinder 40 is connected to the combustion cylinder 40 as shown in FIG. The fuel introduction passage 88 is connected to the fuel pump 8.
The fuel is discharged from the fuel introduction passage 88 to the combustion cylinder 40 by receiving the pump pressure of the fuel pump 89. Further, the combustion cylinder 40 has a glow plug (not shown) that ignites the fuel supplied by the fuel introduction passage 88.

On the outer wall 43 of the combustion type heater 91, a rotating fan (blower means) 90 for blowing air having a motor 92 as a driving source is provided on the side of the combustion cylinder 40 opposite to the side where the flame F is emitted. An enclosed housing 93 is attached.

The housing 93 has an air intake 95 for taking in air from the outside.
Is connected to the air supply pipe 71. Housing 93
Inside the upstream internal space S with the rotating fan 90 interposed therebetween.
And an air passage 94 on the downstream side, and the air passage 94 communicates with the air supply port 62.

In the air passage 94, the gas is allowed to flow from the internal space S toward the combustion tube 40 in the air passage 94, and the gas flows from the combustion tube 40 to the internal space S in the air passage 94. A check valve (communication shut-off means) 96 for preventing the flow is provided. The valve opening pressure of the check valve 96 is set to a predetermined value.
6, the air pressure upstream (in other words, the rotation fan 9).
0 is the combustion gas pressure downstream of the check valve 96 (in other words, the combustion gas pressure in the combustion cylinder 40).
When the pressure exceeds a predetermined value, the check valve 96 is opened, and the combustion air flows through the air passage 94 from the internal space S toward the combustion cylinder 40. When the pressure difference between the air pressure upstream of the check valve 96 and the combustion gas pressure downstream of the check valve 96 is less than the valve opening pressure, the check valve 96 closes.

The rotating fan 90 is driven by the motor 92.
When air is rotated, air is introduced into the internal space S in the housing 93 from the intake passage 14 via the air supply pipe 71, and the air in the internal space S is pressure-fed to the air passage 94 to operate the check valve 96. The valve is opened and supplied through the check valve 96 from the air supply port 62 into the combustion cylinder 40 as combustion air.

Then, the combustion air and the fuel supplied into the combustion cylinder 40 form an air-fuel mixture and are burned in the combustion cylinder 40 to become combustion gas. Thereafter, the combustion gas is introduced from the combustion heater 91 into the intake passage 14 or the exhaust passage 42 via the combustion gas discharge pipe 73 as described above. The amount of combustion gas introduced into the intake passage 14 or the exhaust passage 42, that is, the amount of air introduced into the combustion tube 40 is determined by the number of revolutions of the rotary fan 90. That is,
As the fan rotation speed increases, the air volume increases, and an amount of air proportional to the fan rotation speed is introduced into the combustion tube 40, and after combustion, becomes combustion gas and is discharged from the combustion heater 91. The rotation speed of the rotating fan 90 is controlled by the ECU 11 by the motor 92.
Is determined by controlling.

The ECU 11 comprises a central processing controller CPU, a read-only memory ROM, a random access memory RAM, an input interface circuit, an output interface circuit, and the like, which are interconnected by a bidirectional bus. Various sensors are connected to the input interface circuit via electric wiring. The output interface circuit includes an EGR valve 30, an electric water pump 50, a glow plug of a combustion cylinder 40, and a valve device 7.
8, a three-way switching valve 86, a fuel pump 89, a motor 92 for driving a rotating fan, and the like are connected via electric wiring.

The sensors connected to the input interface circuit include an air flow meter attached to the intake passage 14, a catalyst temperature sensor attached to the catalytic converter 39, a water temperature sensor for detecting the temperature of cooling water contained in the water jacket, and an accelerator. An accelerator position sensor, an ignition switch, a starter switch, and the like attached to a pedal or an accelerator lever that operates in conjunction with an accelerator pedal can be exemplified. These sensors output an electrical signal corresponding to the detected value and send it to the ECU 11. In addition, illustration of these various sensors is omitted.

The ECU 11 determines the operating state of the engine 1 based on the output signal values of the various sensors. Then, the fuel injection control and the like are performed based on the determination result, and the control of the combustion heater 91 is performed.

In the combustion type heater 91 configured as described above, at the time of normal use such as when the heater for cabin heating is operated when the engine 1 is operating, as shown in FIG.
By operating the valve device 78, the valve body 80 is closed, the combustion gas outlet 65 is closed, and the three-way switching valve 86 is controlled to close the branch pipe 84 and open the intake passage 14 side.

The rotating fan 90 is driven by the motor 92.
And a part of the intake air flowing through the intake passage 14 is introduced into the combustion cylinder 40 of the combustion heater 91 via the air supply pipe 71. Further, the fuel pump 89 is operated to suck up fuel in a fuel tank (not shown), and the fuel is supplied from the fuel introduction passage 88 to the combustion cylinder 40. Further, by operating the electric water pump 50, the engine cooling water in the water jacket of the engine 1 is pumped to the heater internal cooling water passage 37 of the combustion type heater 91.

Subsequently, a mixture of the intake air supplied to the combustion cylinder 40 by the rotary fan 90 and the fuel supplied to the combustion cylinder 40 from the fuel introduction passage 88 is supplied to the glow plug of the combustion cylinder 40 by the electric current. The fuel is ignited by the glow plug, a flame F is generated in the combustion tube 40, and the combustion starts.

The high-temperature combustion gas generated by the combustion flows through the combustion chamber 48 toward the combustion gas discharge port 63 by the airflow generated by the rotation of the rotary fan 90, and further passes through the connection pipe 74 to the combustion gas discharge pipe 73. (See solid arrow a3 in FIG. 2).

On the other hand, the engine cooling water pumped from the water jacket to the heater internal cooling water passage 37 of the combustion type heater 91 via the cooling water introduction passage W1 by a water pump or an electric water pump 50 built in the engine is: The gas flows so as to circulate through the heater internal cooling water passage 37 over the entire outer surface of the partition wall 41, and absorbs the heat of the combustion gas during that time to rise. In other words, the heater internal cooling water passage 37
Heat is exchanged between the engine cooling water and the combustion gas in the entire area of the engine.

Then, the engine cooling water having absorbed the heat of the combustion gas is introduced from the heater internal cooling water passage 37 to the heater core 10 through the cooling water discharge passage W2.
The engine cooling water discharged from 0 is discharged to the cooling water discharge passage W3,
Return to the water jacket of the engine body 3 (see the dashed arrow in FIG. 2 and the dashed line in FIG. 1). In the heater core 10, a part of the heat of the engine cooling water is exchanged with the heating air, and the temperature of the heating air rises. As a result, warm air is generated in the vehicle cabin.

As described above, the engine cooling water, which has been heated by the combustion type heater 91 and has become high heat, flows to the water jacket and the heater core 10 of the engine body 3, and as a result, the warming-up of the internal combustion engine and the startability are improved. Improvement, heater core 1
The performance of 0 is improved.

When the combustion gas discharged into the combustion gas discharge pipe 73 reaches the three-way switching valve 86, the combustion gas is supplied to the three-way switching valve 86 because the branch pipe 84 is closed and the intake passage 14 is open. Connection point C2 upstream of the throttle valve 51
To the intake passage 14. Then, the combustion gas returned to the intake passage 14 is supplied to the combustion chamber of the engine body 3 together with the intake air not introduced into the combustion type heater 91,
An air-fuel mixture is formed with fuel injected from a fuel injection valve (not shown) and is supplied to combustion (see a solid line arrow in FIG. 1).

At this time, the combustion chamber of the engine body 3 is supplied with the combustion gas whose temperature has been lowered by heat exchange with the cooling water in the combustion type heater 91, so that the high-temperature intake air is sucked in for a long time. This prevents heat damage to the engine 1. Further, by supplying a small amount of combustion gas having a relatively high CO ₂ concentration to the combustion chamber of the engine body 3, NOx generated by combustion in the combustion chamber of the engine body 3 is reduced.
The amount can be reduced efficiently. Further, the combustion gas discharged from the combustion type heater 91 is reburned in the combustion chamber of the engine body 3, and the exhaust gas discharged from the combustion chamber of the engine body 3 is further purified by the catalytic converter 39. Therefore, the combustion gas discharged from the combustion type heater 91 can be purified and then released to the outside air.

Further, the combustion gas discharged from the combustion heater 91 is supplied to the intake passage 14 downstream of the intercooler 19.
, It does not flow into the compressor 15a and the intercooler 19 of the turbocharger 15, so that heat damage to these is also prevented.

Incidentally, as described above, the combustion type heater 91 is used.
At the connection point C2 through the combustion gas discharge pipe 73.
When the air supply pipe 71 is returned to the intake passage 14, an unexpected situation occurs, and the air supply pipe 71 is broken in the middle, or a connection portion between the air supply pipe 71 and the intake passage 14 or the air supply pipe 71.
When the air intake 95 of the combustion type heater 91 is in communication with the atmosphere as a result of the connection between the air intake 95 and the combustion type heater 91 being disconnected, etc., the combustion gas discharge pipe 7
3 communicates with the intake passage 14, the pressure of the intake air boosted by the turbine 15a of the turbocharger 15 is combusted through the combustion gas discharge pipe 73, the three-way switching valve 86, the connection pipe 74, and the combustion chamber 48. Since it is transmitted to the inside of the cylinder 40 and further transmitted to the downstream side of the check valve 96 in the air passage 94 through the air supply port 62, the check valve 96 in the air passage 94 immediately after the occurrence of the unexpected situation. The pressure on the downstream side of increases sharply. On the other hand, since the upstream side of the check valve 96 in the air passage 94 communicates with the air intake 95 via the internal space S, the pressure on the upstream side of the check valve 96 in the air passage 94 is the unexpected value. Immediately after the occurrence of the above situation, it becomes almost atmospheric pressure. As a result, even if the rotating fan 90 is rotating, the gas pressure downstream of the check valve 96 in the air passage 94 is higher than the gas pressure upstream of the check valve 96. In the course of this pressure change, the differential pressure between the gas pressure on the upstream side of the check valve 96 and the gas pressure on the downstream side (more precisely, the gas pressure on the upstream side with respect to the gas pressure on the downstream side of the check valve 96) Check valve 96)
, The check valve 96 is immediately closed at that time.

Therefore, it is possible to prevent the high-pressure intake air in the intake passage 14 from flowing backward from the connection point C2 to the combustion gas exhaust pipe 73, and the intake air is supplied to the three-way switching valve 8
6. It is possible to prevent the backflow to the connecting pipe 74, the combustion chamber 48, and the combustion cylinder 40, and the high-temperature combustion gas in the combustion chamber 48 passes through the combustion cylinder 40, the air intake 62, and the air passage 94, and is Backflow to the space S can be prevented. As a result, it is possible to prevent the components of the rotating fan 90 from being burned, and to prevent the electrical components such as the wiring connected to the motor 92 from being burned.

If the check valve 96 is not provided, the high-pressure intake air from the intake passage 14 passes through the combustion gas discharge pipe 73 and the combustion of the combustion type heater 91 when the above-mentioned unexpected situation occurs. As a result, the high-temperature combustion gas in the combustion chamber 48 flows back into the internal space S through the air passage 94 to burn out the resin component of the rotating fan 90,
There is a possibility that the wiring of the motor 92 may be burned. However, in the internal combustion engine of this embodiment, the provision of the check valve 96 can prevent such a problem beforehand, and is extremely excellent in fail-safe.

Next, when promoting warm-up of the catalytic converter 39, when performing a process of recovering the catalytic converter 39 from SOx poisoning or SOF poisoning (hereinafter, referred to as a poisoning recovery process), If it is necessary to raise the temperature of the catalytic converter 39 during the reduction process for the catalytic converter 39, as shown in FIG. 3, the valve element 80 opens the opening 79a by the operation of the valve device 78, and thereby the combustion gas is discharged. The outlet 65 is opened, and the three-way switching valve 86 is controlled to close the intake passage 14 and open the branch pipe 84.

The rotating fan 90 is driven by the motor 92.
And a part of the intake air flowing through the intake passage 14 is supplied to the combustion cylinder 40 of the combustion type heater 91. Further, the fuel pump 89 is operated to supply fuel from the fuel introduction passage 88 to the combustion cylinder 4.
0.

Subsequently, a mixture of intake air supplied to the combustion cylinder 40 by the rotary fan 90 and fuel supplied to the combustion cylinder 40 from the fuel introduction passage 88 is supplied to the glow plug of the combustion cylinder 40 by energizing the glow plug. The fuel is ignited by the glow plug and is burned in the combustion tube 40.

The high-temperature combustion gas generated by this combustion is:
The combustion chamber 48 flows toward the combustion gas discharge port 65 by the airflow generated by the rotation of the rotating fan 90. Most of the combustion gas is discharged to the combustion gas discharge pipe 73 through the combustion gas discharge port 65 and the opening 79a of the valve device 78 (see the solid line arrow a4 in FIG. 3).

Here, the combustion gas flowing through the combustion gas discharge port 63 is cooled by heat exchange with the engine cooling water, but the combustion gas flowing through the combustion gas discharge port 65 is cooled by the engine cooling water. There is almost no heat exchange. Therefore, the temperature of the combustion gas discharged from the combustion gas discharge port 65 is considerably higher than that of the combustion gas discharged from the combustion gas discharge port 63.

When the high-temperature combustion gas discharged to the combustion gas discharge pipe 73 via the combustion gas discharge port 65 reaches the three-way switching valve 86, the three-way switching valve 86 closes the intake passage 14 side and closes the branch pipe 84 side. Since it is open, the combustion gas flows to the branch pipe 84 and exits from the connection point C3 upstream of the catalytic converter 39 to the exhaust passage 42 (see the dashed arrow in FIG. 1). In this embodiment, a portion of the combustion gas discharge pipe 73 connecting the valve device 78 and the three-way switching valve 86 and the branch pipe 84 constitute a combustion gas discharge passage.

The combustion gas of the combustion type heater 91 discharged to the connection point C3 of the exhaust passage 42
The exhaust gas is mixed with the exhaust gas discharged from the exhaust passage and flowing through the exhaust passage 42. As a result, the temperature of the exhaust gas is increased, and flows into the catalytic converter 39 together with the exhaust gas to increase the temperature.

Therefore, by supplying the high-temperature combustion gas discharged from the combustion gas discharge port 65 to the connection point C3 upstream of the catalytic converter 39 in the exhaust passage 42, the temperature of the catalytic converter 39 is quickly raised to a high temperature. be able to.

Here, during the operation of the engine 1, the exhaust gas pressure in the exhaust passage 42 upstream of the catalytic converter 39 increases, but the combustion air of the combustion type heater 91 is supplied from the downstream of the compressor 15 a of the turbocharger 15. As a result of the suction, the combustion gas pressure of the combustion type heater 91 can be made higher than the exhaust gas pressure in the exhaust passage 42 at the connection point C3 by using the supercharging pressure of the turbocharger 15, so that even during the operation of the engine 1 The combustion gas from the combustion heater 91 can be discharged to the exhaust passage 42 upstream of the catalytic converter 39. In addition, even when the turbocharger 15 is supercharging, the exhaust gas does not flow backward in the combustion cylinder 40 of the combustion heater 91, and misfire due to flashback can be prevented.

The combustion gas discharged from the combustion type heater 91 flows into the exhaust passage 42 downstream of the turbine 15b of the turbocharger 15 and upstream of the catalytic converter 39, so that the turbocharger 15 and the exhaust manifold 28 , And there is no cooling in these, so that the high temperature combustion gas can be used for heating the catalytic converter 39 by the amount not cooled, and the catalyst warm-up property is improved and the catalyst temperature is raised efficiently. be able to.

Further, the combustion gas discharged from the combustion type heater 91 is supplied to the compressor 15 of the turbocharger 15.
Since it does not flow through the intercooler 19 and the intercooler 19, the heat damage thereof can be prevented.

By the way, as described above, the combustion type heater 91
When the combustion gas is returned to the exhaust passage 42 at the connection point C3 via the combustion gas discharge pipe 73 and the branch pipe 84, an unexpected situation occurs, and the air supply pipe 71 is torn in the middle, As a result, the connection between the pipe 71 and the intake passage 14 and the connection between the air supply pipe 71 and the air inlet 95 of the combustion heater 91 are disconnected.
When the air inlet 95 of the air communication is in communication with the atmosphere, since the branch pipe 84 is in communication with the exhaust passage 42, the exhaust gas pressure in the exhaust passage 42 is reduced by the branch pipe 84 and the three-way switching valve 8.
6, combustion gas exhaust pipe 73, valve chamber 79, combustion gas exhaust port 6
5, transmitted through the combustion chamber 48 into the combustion cylinder 40, and further transmitted through the air supply port 62 to the air passage 94 downstream of the check valve 96. In particular, turbocharger 1
The exhaust passage 4 is operated when the supercharging pressure of
Since the pressure of the exhaust gas in the air passage 2 also increases, the pressure on the downstream side of the check valve 96 in the air passage 94 increases rapidly immediately after the occurrence of the unexpected situation. On the other hand, since the upstream side of the check valve 96 in the air passage 94 communicates with the air intake 95 via the internal space S, the pressure on the upstream side of the check valve 96 in the air passage 94 is the unexpected value. Immediately after the occurrence of the above situation, it becomes almost atmospheric pressure. As a result, even if the rotating fan 90
Is rotated, the check valve 96 is provided in the air passage 94.
Is higher than the gas pressure on the upstream side of the check valve 96. In the course of this pressure change, the differential pressure between the gas pressure on the upstream side of the check valve 96 and the gas pressure on the downstream side (more precisely, the gas pressure on the upstream side with respect to the gas pressure on the downstream side of the check valve 96) Check valve 9)
6, the check valve 96 is closed immediately.

Therefore, the high-pressure exhaust gas in the exhaust passage 42 can be prevented from flowing back from the connection point C3 to the branch pipe 84.
6. It is possible to prevent the gas from flowing back to the combustion gas discharge pipe 73, the combustion gas discharge port 65, the combustion chamber 48, and the combustion cylinder 40.
It is possible to prevent the high-temperature combustion gas in the combustion chamber 48 from flowing back to the internal space S through the combustion tube 40, the air inlet 62, and the air passage 94. As a result, it is possible to prevent the resin components of the rotating fan 90 from being burned, and it is also possible to prevent the electrical components such as wiring connected to the motor 92 from being burned.

If the check valve 96 is not provided, the high-pressure exhaust gas is discharged from the exhaust passage 42 through the branch pipe 84 and the combustion gas discharge pipe 73 when the above-mentioned unexpected situation occurs. As a result, the high-temperature combustion gas in the combustion chamber 48 flows back through the air passage 94 into the internal space S, burning the components of the rotary fan 90 or burning out the motor 92. There is a risk of burning out the wiring and the like. However, in the internal combustion engine of this embodiment, the provision of the check valve 96 can prevent such a problem beforehand, and is extremely excellent in fail-safe.

[0070]

As described above, according to the internal combustion engine having the combustion type heater according to the present invention, the air supply passage for introducing combustion air to the combustion type heater is broken during the operation of the supercharger. Even if an unexpected situation such as occurs, it is possible to prevent the high-temperature combustion gas of the combustion heater from flowing back from the combustion chamber of the combustion heater to the blowing means, and as a result, burnout of the blowing means and the like can be prevented. Can be prevented.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view showing an operation state of a combustion type heater.

FIG. 3 is a sectional view showing another operation state of the combustion type heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine) 3 ... Engine main body 5 ... Intake device 7 ... Exhaust device 8 ... EGR device 10 ... Heater core 11 ... ECU 13 ... Air cleaner 14 ... Intake passage 15 ... Turbocharger 15a ... Compressor 15b ... Turbine 19 ... Intercooler Reference Signs List 22 intake manifold 28 exhaust manifold 30 EGR valve 37 heater internal cooling water passage 37 a cooling water inlet 37 b cooling water outlet 39 catalytic converter 40 combustion cylinder 41 partition 42 exhaust passage 43 outer wall 48 ... combustion chamber 50 ... electric water pump 51 ... intake throttle valve 62 ... air supply port 63 ... combustion gas discharge port 65 ... combustion gas discharge port 71 ... air supply pipe (air supply path) 73 ... combustion gas discharge pipe (combustion gas discharge) (Passage) 74 ... connecting pipe 78 ... valve device 79 ... valve chamber 80 ... valve body 8 ... EGR passage 82 ... Actuator 84 ... Branch pipe (combustion gas discharge passage) 86 ... Three-way switching valve (combustion gas path switching means) 88 ... Fuel introduction passage 89 ... Fuel pump 90 ... Rotary fan (blowing means) 91 ... Combustion heater 92 ... Motor 93 ... Housing 94 ... Air passage 95 ... Air intake 96 ... Check valve (communication shut-off means) C1 ... Connection point between air supply pipe 71 and intake passage 14 C2 ... Combustion gas discharge pipe 73 and intake passage 14 Connection point C3: Connection point between exhaust passage 14 and branch pipe 84 F: Flame S: Internal space of housing 93 W: Heat medium circulation path W1: Cooling water introduction path W2: Cooling water discharge path W3: Cooling water discharge Road

Claims (2)

[Claims] 1. A combustion air is introduced from an intake passage of an internal combustion engine, mixed with fuel, and the mixture is burned in a combustion chamber. An internal combustion engine having a combustion type heater, which comprises: a supercharger that boosts intake air in the intake passage; an air supply passage that introduces the intake air boosted by the supercharger as the combustion air; and a cylinder of the internal combustion engine. A combustion gas discharge passage for bypassing and introducing the combustion gas into an exhaust passage of the internal combustion engine; and a combustion air provided between the air supply passage and the combustion chamber and introduced from the air supply passage to the combustion chamber. Blower means for introducing the combustion gas generated in the combustion chamber into the combustion gas discharge passage, and communication provided between the blower means and the combustion chamber to allow and prevent the flow of gas therebetween. Blocking means and An internal combustion engine having a combustion type heater provided. 2. A combustion gas, wherein the intake passage and the combustion gas discharge passage downstream of a connection point with the air supply passage can selectively switch combustion gas to an exhaust passage or an intake passage. The internal combustion engine having a combustion type heater according to claim 1, wherein the internal combustion engine is connected via a path switching unit.