JP3531518B2 - Internal combustion engine having a combustion heater - Google Patents

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

[0002]

2. Description of the Related Art A lean-burn engine such as a diesel engine, a lean-burn engine, or the like mounted on a vehicle such as an automobile produces a smaller amount of heat than an ordinary gasoline engine. Therefore, the lean-burn engine is often equipped with a combustion heater for the purpose of promoting warm-up especially in cold weather and improving the performance of the vehicle interior heating device.

The basic principle of the combustion type heater is that the heat of the combustion gas generated when the fuel is burned in the combustion chamber of the combustion type heater is a heat medium (for example, a heat medium) that can be distributed around the combustion chamber.
The heat medium is absorbed by water) to heat the heat medium, and the heated heat medium is sent to the water jacket of the engine body, the heater core for heating the vehicle compartment, and other necessary places to raise the temperature of these required places.

Japanese Unexamined Patent Publication No. 60-78819 discloses an internal combustion engine having a conventional combustion 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 inlet of a combustion heater, and the introduced combustion air is burned by a blower fan. It is sent under pressure to the combustion chamber of the heater, mixed with the fuel supplied to the combustion chamber, and the combustion gas produced by burning the mixture is discharged from the combustion gas discharge port to the exhaust passage upstream of the catalytic converter, and the combustion gas is discharged to the engine. The exhaust gas emitted from the exhaust gas is purified by a catalytic converter. In the above publication, the purpose of introducing the combustion gas into the exhaust passage is to purify the combustion gas, but the purpose of introducing the combustion gas into the exhaust passage is not limited to this, and various purposes such as temperature rise of the catalyst are possible. is there.

[0005]

By the way, in an exhaust gas purification system for an internal combustion engine, an HC adsorbent may be installed upstream of the catalytic converter in order to prevent HC emission at the time of starting the internal combustion engine. This is because when the internal combustion engine is started, the exhaust gas temperature is low and the catalytic converter does not reach the catalyst activation temperature.
Is adsorbed and the exhaust gas is purified by the catalytic converter including the HC desorbed from the HC adsorbent after the catalyst is warmed up.

However, in this case, if the temperature of the exhaust gas is raised in order to warm up the catalyst of the catalytic converter, the HC adsorbent disposed upstream of the catalytic converter also rises in temperature, so that the downstream catalytic converter is Before the activation temperature is reached, HC is desorbed from the HC adsorbent, resulting in deterioration of HC emission of exhaust gas.

The present invention has been made in view of such problems, and the problem to be solved by the present invention is HC
An object of the present invention is to provide an internal combustion engine having a combustion heater capable of preventing deterioration of emission.

[0008]

The present invention adopts the following means in order to solve the above problems. The present invention introduces combustion air from an intake passage of an internal combustion engine to mix it with fuel,
In an internal combustion engine having a combustion heater that heats engine-related elements by utilizing heat of combustion gas produced by burning the mixture in a combustion chamber, an HC adsorbent provided in an exhaust passage of the internal combustion engine A NOx catalyst provided in the exhaust passage downstream of the HC adsorbent, and a combustion gas exhaust passage for bypassing the cylinder of the internal combustion engine and introducing the combustion gas between the HC adsorbent and the NOx catalyst. And are provided.

In this internal combustion engine, when the internal combustion engine is started, the combustion gas of the combustion type heater is mixed with HC adsorbent and NOx.
It is introduced between the catalysts and the heat of the combustion gas is used to warm up the NOx catalyst. Before the NOx catalyst is warmed up, the temperature of the exhaust gas emitted from the internal combustion engine is also low, and HC in this exhaust gas is adsorbed by the HC adsorbent. The exhaust gas temperature rises with the lapse of time from the start of the internal combustion engine, and the temperature of the HC adsorbent rises accordingly. The HC adsorbent continues to adsorb HC in the exhaust gas until its temperature reaches the HC desorption temperature, and adsorbs HC when it reaches the HC desorption temperature.
Desorb. However, by the time the HC is desorbed from the HC adsorbent, the NOx catalyst has been warmed up and the NOx catalyst has reached the catalyst activation temperature. Therefore, the HC desorbed from the HC adsorbent is purified by the NOx catalyst. To be done.

The engine-related elements are engine cooling water, an internal combustion engine main body for introducing combustion gas of a combustion type heater into intake air, an NOx catalyst as exhaust gas purifying means provided in an exhaust passage, and the like.

The HC adsorbent has the property of adsorbing hydrocarbons (HC) until the adsorbent temperature reaches the HC desorption temperature, and desorbing the adsorbed HC when the adsorbent temperature reaches the HC desorption temperature. For example, it can be composed of a porous body such as zeolite, and can also be composed by supporting a catalyst such as an oxidation catalyst on a carrier such as zeolite.

As the NOx catalyst, a selective reduction type NOx catalyst or a storage reduction type NOx catalyst can be exemplified. Here, the selective reduction type NOx catalyst refers to a catalyst that reduces or decomposes NOx in the presence of hydrocarbons in an atmosphere of excess oxygen, such as a catalyst in which a transition metal such as Cu is ion-exchanged and supported, a zeolite, or A catalyst in which a noble metal is supported on alumina is included.

The NOx storage reduction catalyst is a catalyst that absorbs NOx when the air-fuel ratio of the inflowing exhaust gas is lean, and releases the absorbed NOx and reduces it to N ₂ when the oxygen concentration in the inflowing exhaust gas decreases. And, for example, using alumina as a carrier on which potassium K, sodium Na,
At least one selected from an alkali metal such as lithium Li and cesium Cs, an alkaline earth such as barium Ba and calcium Ca, a rare earth such as lanthanum La and yttrium Y, and a noble metal such as platinum Pt are supported. Can be configured.

In the internal combustion engine having the combustion heater according to the present invention, a supercharger for boosting the intake air in the intake passage, and an air supply passage for introducing the intake air boosted by the supercharger as the combustion air. And can be provided.
With this configuration, the combustion gas of the combustion gas heater can be introduced into the exhaust passage even when the pressure of the exhaust gas is high.

In this case, the intake passage and the combustion gas discharge passage downstream of the connection point with the air supply passage are selectively switched over between the exhaust passage and the intake passage for introducing the combustion gas. It can be connected via possible combustion gas path switching means. By doing so, the combustion gas path can be switched by the combustion gas path switching means, and the combustion gas can be introduced into the intake passage to raise the temperature of the engine-related element of the intake system, or the combustion gas can be exhausted through the exhaust passage. It is possible to raise the temperature of the engine-related element of the exhaust system by introducing it into the engine.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an internal combustion engine having a combustion heater according to the present invention will be described below with reference to FIGS.
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. The engine 1 has an engine main body 3 having a water jacket (not shown) containing engine cooling water and a plurality of cylinders (not shown) of the engine main body 3, which are provided with air necessary for combustion, as schematically shown in FIG. An air-fuel mixture that is sent in and a mixture of air that is sent to the cylinder through the air-intake device 5 and engine fuel that is injected and supplied into the cylinder is burned in a combustion chamber, and then exhaust gas that is emitted from the cylinder is released to the atmosphere. Exhaust system 7, an EGR system 8 as an exhaust gas recirculation system that suppresses the generation of nitrogen oxides by recirculating exhaust gas from the exhaust system 7 toward the intake system 5, and the engine 1
Separately from the above, the combustion type heater 91 that burns fuel and heats the engine-related elements by the heat of the combustion gas generated at that time, the heater core 10 that is the vehicle interior heating device that raises the indoor temperature of the vehicle equipped with the engine, and the entire engine are It has ECU11 which is an engine control device which controls.

The intake device 5 has an intake passage 14 starting from an air cleaner 13 for filtering the outside air and ending at 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, intercooler 1 for cooling intake air temperature raised by compression heat generated when compressor 15a is operated
9. An intake manifold 22 which is a suction branch pipe is sequentially arranged. An intake throttle valve 51 that controls 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 which starts at an exhaust port (not shown) of the engine body 3 and ends at a muffler (not shown). In the exhaust passage 42, an exhaust manifold 28 that is an exhaust branch pipe, a turbine 15b of the turbocharger 15, and an HC adsorbent 38 that is an exhaust gas purification device are provided between the exhaust port and the muffler.
And the catalytic converter 39 are sequentially arranged.

The HC adsorbent 38 adsorbs hydrocarbons (HC) until the adsorbent temperature reaches the HC desorption temperature.
It has a property of desorbing adsorbed HC when it reaches the C desorption temperature, and can be composed of, for example, a porous body such as zeolite. Note that the HC desorption temperature depends on the HC adsorbent
It depends on the configuration. The catalytic converter 39 includes an N-type catalyst such as a selective reduction type NOx catalyst or a storage reduction type NOx catalyst.
It contains an Ox catalyst.

The EGR device 8 connects the intake passage 14 and the exhaust passage 42 to bypass the engine body 3 and returns the exhaust gas emitted 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 the combustion gas generated by burning the same fuel as the fuel used in the engine 1 into the intake passage 14 so as to flow through the intake device 5 by utilizing the heat of the combustion gas. It is a heater that can raise the temperature of intake air. The intake air heated by the combustion heater 91 flows through the intake passage 14 toward the cylinder while containing combustion gas.

Further, the combustion heater 91 is adapted to warm the engine cooling water with the heat of the combustion gas, and the warmed engine cooling water is required to raise the temperature of the heater core 10 and the engine body 3. Then, the temperature is raised to the location where the temperature rise is required (in the drawing, only the heater core 10 and the engine body 3 are shown as the temperature rise location). A heat medium circulation passage W is provided in the engine 1 so that the engine cooling water warmed by the combustion heater 91 can be sent to the location where the temperature rise is required.

The heat medium circulation path W connects the engine body 3 and the combustion heater 91, and introduces the engine cooling water from the water jacket of the engine body 3 to the combustion heater 91, and the combustion heater 91. It has a cooling water discharge passage W2 for guiding the engine cooling water warmed up to the heater core 10 and a cooling water discharge passage W3 for returning the engine cooling water discharged from the heater core 10 to the water jacket of the engine body 3. In addition, the electric water pump 5 is installed in the cooling water introduction passage W1.
0 is provided, and in addition to the circulation of cooling water by a water pump with a built-in engine (not shown), the operation of this electric water pump 50 promotes circulation of the engine cooling water in the heat medium circulation passage W. .

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

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 heater 91.

The combustion chamber 48 includes a combustion tube 40 as a combustion source for generating the flame F, and a cup-shaped partition wall 41 that covers the combustion tube 40 to prevent the flame F from leaking to the outside.
Consists of. By covering the combustion cylinder 40 with the partition wall 41,
The combustion chamber 48 is defined in the partition wall 41. The partition wall 41 is also covered with the outer wall 43 of the combustion 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. While the engine cooling water flows in the heater internal cooling water passage 37, the engine cooling water receives heat from the combustion chamber 48. That is, the engine cooling water exchanges heat with the high-temperature combustion gas in the combustion chamber 48 to raise the temperature.

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

Further, the combustion gas discharge port 65 is on the side where the flame F exits from the combustion tube 40, and faces the flame F and the partition wall 4
1 and the outer wall 43. The combustion gas discharge ports 63 and 65 are connected via a connecting pipe 74 extending in parallel with the longitudinal direction of the combustion heater 91. Then, the air supply port 62 and the combustion gas discharge ports 63, 65
Both communicate with the intake passage 14. That is, the air supply port 62 communicates with the intake passage 14 via the air supply pipe (air supply passage) 71 that supplies combustion air from the intake passage 14 to the combustion heater 91, and the combustion gas discharge port 6
Reference numerals 3 and 65 denote a connecting 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 more than C1. Downstream. Also, the connection points C1 and C2
Are both located upstream of the intake throttle valve 51 and downstream of the intercooler 19.

The combustion gas discharge pipe 73 is provided with 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 that opens and closes the combustion gas discharge port 65 therein. The valve chamber 79 has two openings 79a and 79b.
The 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 the valve body 80. When the valve element 80 is actuated by the actuator 82, the opening 79a is opened and closed, which opens and closes the combustion gas discharge port 65.

A three-way switching valve (combustion gas path switching means) 86 having three ports (first, second and third ports) is attached to the middle of the combustion gas discharge pipe 73. The first port of the three-way switching valve 86 is connected to the combustion gas exhaust pipe 73 connected to the valve device 78, the second port is connected to the combustion gas exhaust pipe 73 connected to the intake passage 14, and the third port bypasses the engine body 3. (That is, bypassing the cylinder of the engine body 3) is connected to the branch pipe 84, which connects the HC adsorbent 38 and the catalytic converter 3 to each other.
It is connected to the exhaust passage 42 (connection point C3) between the nine.

The three-way switching valve 86 allows the combustion gas to pass through the intake passage 1
4 is a switching valve that selectively switches between flowing toward the nozzle 4 and flowing toward the branch pipe 84. The operation of the three-way switching valve 86 determines whether to introduce the combustion gas 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 into 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.
9, 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.

Further, on the outer wall 43 of the combustion heater 91, a rotary fan 90 for blowing having a motor 92 as a drive source on the side of the combustion cylinder 40 opposite to the side where the flame F exits.
A housing 93 enclosing is attached.

The housing 93 has an air intake 95 for taking in air from the outside.
The air supply pipe 71 is connected to. Further, the housing 93 has an internal space S communicating with the air supply port 62. Therefore, the air supply port 62 is indirectly connected to the air supply pipe 71 via the internal space S.

Then, the rotary fan 90 is driven by the motor 92.
When is rotated, air is introduced into the housing 93 from the intake passage 14 via the air supply pipe 71. The air guided to the housing 93 passes through the internal space S and is supplied from the air supply port 62 to the combustion cylinder 40 as combustion air. Then, the combustion gas after the fuel is burned by this combustion air is then burned by the combustion heater 91.
Is introduced into the intake passage 14 or the exhaust passage 42 through the combustion gas discharge pipe 73 as described above. Intake passage 1
4 or the amount of combustion gas introduced into the exhaust passage 42, that is, the amount of air introduced into the combustion tube 40,
Determined by a fan speed of 0. 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 cylinder 40, and becomes combustion gas after combustion to be discharged from the combustion heater 91. The rotation speed of the rotary fan 90 is determined by controlling the motor 92 by the ECU 11.

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

The sensors connected to the input interface circuit include an air flow meter installed in the intake passage 14, a catalyst temperature sensor installed in the catalytic converter 39, a water temperature sensor for detecting the temperature of cooling water contained in the water jacket, and an accelerator. Examples thereof include an accelerator position sensor, an ignition switch, and a starter switch, which are attached to a pedal or an accelerator lever that operates in conjunction with the accelerator pedal. 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 illustrated is omitted.

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

In the combustion heater 91 having the above-described structure, when the engine is started, the valve 80 is opened by the operation of the valve device 78 and the opening 79a is opened immediately after the engine 1 is started, as shown in FIG. Thus, the combustion gas discharge port 65 is opened, and the three-way switching valve 86 is controlled to close the intake passage 14 side and open the branch pipe 84.

Then, the rotary fan 90 is driven by the motor 92.
Rotates and supplies a part of the intake air flowing in the intake passage 14 to the combustion cylinder 40 of the combustion heater 91 via the air supply pipe 71. Further, the fuel pump 89 sucks up the fuel in the fuel tank (not shown), and the fuel is introduced into the fuel introduction passage 88.
To the combustion cylinder 40.

Next, the 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 energized by the glow plug of the combustion cylinder 40. The glow plug ignites, a flame F is generated in the combustion cylinder 40, and combustion is started.

The high temperature combustion gas generated by this combustion is
The combustion chamber 48 flows toward the combustion gas discharge port 65 by the air flow generated by the rotation of the rotary 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 exhaust port 63 is cooled by heat exchange with the engine cooling water, but the combustion gas flowing through the combustion gas exhaust port 65 is exchanged with the engine cooling water. Almost no heat exchange takes place. Therefore, the combustion gas discharged from the combustion gas discharge port 65 has a considerably higher temperature than the combustion gas discharged from the combustion gas discharge port 63.

Then, the high-temperature combustion gas discharged to the combustion gas discharge pipe 73 through the combustion gas discharge port 65 reaches the three-way switching valve 86. Since the intake passage 14 side is closed and the branch pipe 84 side is opened in the three-way switching valve 86, the combustion gas flows into the branch pipe 84 and exits from the connection point C3 upstream of the catalytic converter 39 to the exhaust passage 42 (broken line in FIG. 1). (See arrow). In this embodiment, the combustion gas exhaust pipe 7
The branch pipe 84 and the portion of the valve 3 that connects the valve device 78 and the three-way switching valve 86 together form 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 is the engine body 3 here.
The exhaust gas is mixed with the exhaust gas flowing through the exhaust passage 42, and as a result, the temperature of the exhaust gas is raised, and the exhaust gas flows into the catalytic converter 39 together with the exhaust gas to raise the temperature thereof.

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 catalytic converter 39 can be warmed up early. .

Immediately after the engine 1 is started, the temperature of the exhaust gas discharged from the engine body 3 is low and the catalytic converter 39 has not reached the catalytic activation temperature. However, at this time, HC contained in the exhaust gas is adsorbed by HC. Since it is adsorbed by the agent 38, it can be discharged to the atmosphere as exhaust gas having a low HC concentration.

Then, although the exhaust gas temperature rises with the lapse of time from the start of the engine 1, the HC adsorbent 3
The adsorption of HC by the HC adsorbent 38 continues until 8 reaches the HC desorption temperature (for example, 180 ° C.).

Then, as the exhaust gas temperature rises, HC
When the temperature of the adsorbent 38 rises and the temperature of the HC adsorbent 38 reaches the HC desorption temperature, the adsorbed HC becomes HC
The adsorbent 38 is desorbed. At this time, the catalytic converter 39 has already been warmed up by the combustion gas of the combustion heater 91, and the catalytic converter 39 has reached the catalyst activation temperature. Therefore, the HC desorbed from the HC adsorbent 38 is removed by the catalytic converter. At 39, it will be burned and will be used for NOx reduction.

Therefore, by introducing the combustion gas of the combustion heater 91 between the HC adsorbent 38 and the catalytic converter 39, the HC emission of the exhaust gas is deteriorated during and after the warming up of the catalytic converter 39. It is possible to discharge clean exhaust gas to the atmosphere.

Here, while the engine 1 is operating, the exhaust gas pressure in the exhaust passage 42 upstream of the catalytic converter 39 increases, but the combustion air of the combustion heater 91 is supplied from the downstream of the compressor 15a of the turbocharger 15. As a result of the intake, the combustion gas pressure of the combustion heater 91 can be made higher than the exhaust gas pressure in the exhaust passage 42 at the connection point C3 by utilizing the supercharging pressure of the turbocharger 15, so that the engine 1 is operated. The combustion gas of the combustion heater 91 can be discharged to the exhaust passage 42 upstream of the catalytic converter 39. Further, even when supercharging is performed by the turbocharger 15, backflow of exhaust gas does not occur in the combustion tube 40 of the combustion heater 91, and misfire due to backfire can be prevented.

Further, the combustion gas discharged from the combustion heater 91 flows out into the exhaust passage 42 between the HC adsorbent 38 and the catalytic converter 39 downstream of the turbine 15b of the turbocharger 15, so that the turbocharger 1
5, exhaust manifold 28, HC adsorbent 38
Since they do not flow in the above, and are not cooled in these, the high temperature combustion gas can be used for heating the catalytic converter 39 by the amount that is not cooled, and the catalyst can be warmed up efficiently.

Further, the combustion gas discharged from the combustion heater 91 is the compressor 15 of the turbocharger 15.
Since it does not flow through a and the intercooler 19, it is possible to prevent the heat damage.

Further, even when the so-called preheating of the catalytic converter 39 is performed, in which the catalytic converter 39 is heated to the activation temperature before the engine 1 is started, the warm-up of the catalytic converter 39 at the time of starting the engine 1 described above is performed. Similarly, by operating the valve device 78, the valve body 80 is opened to open the combustion gas discharge port 65, and the intake passage 1 of the three-way switching valve 86 is opened.
4 side is closed, branch pipe 84 is opened, combustion type heater 91
It can be carried out by introducing the combustion gas of No. 2 between the HC adsorbent 38 and the catalytic converter 39.

Next, during normal use such as when the heater for heating the vehicle compartment is operated when the engine 1 is operating, FIG.
As shown in FIG.
To close the combustion gas discharge port 65, and further control the three-way switching valve 86 to close the branch pipe 84 and open the intake passage 14 side.

By rotating the rotary fan 90, a part of the intake air flowing through the intake passage 14 is supplied to the air supply pipe 7.
1 to the combustion tube 40 of the combustion heater 91.
Further, the fuel pump 89 is operated to discharge the fuel 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 pressure-fed to the heater internal cooling water passage 37 of the combustion type heater 91.

Next, the 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 energized by the glow plug of the combustion cylinder 40. The glow plug ignites, a flame F is generated in the combustion cylinder 40, and combustion is started.

The high temperature combustion gas generated by the combustion flows through the combustion chamber 48 toward the combustion gas discharge port 63 by the air flow generated by the rotation of the rotary fan 90, and further passes through the connecting pipe 74 and the combustion gas discharge pipe 73. Is discharged to (Fig. 2
Solid arrow a3).

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 by the water pump built in the engine or the electric water pump 50 via the cooling water introducing passage W1 is The heater internal cooling water passage 37 flows so as to circulate over the entire outer surface of the partition wall 41, while absorbing the heat of the combustion gas and rising. In other words, the heater internal cooling water passage 37
The heat is exchanged between the engine cooling water and the combustion gas in the whole area of.

The engine cooling water that has 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, and the heater core 1
The engine cooling water from 0 is discharged to the cooling water discharge passage W3,
Return to the water jacket of the engine body 3 (see the broken line arrow in FIG. 2 and the broken line in FIG. 1). In the heater core 10, part of the heat of the engine cooling water is heat-exchanged with the heating air, and the temperature of the heating air rises. As a result, warm air is emitted inside the vehicle.

As described above, the engine cooling water, which has been heated by the combustion heater 91 and becomes high in temperature, flows to the water jacket of the engine body 3 and the heater core 10, and as a result, warming up and starting of the internal combustion engine are facilitated. Improvement, heater core 1
Performance of 0 is improved.

Further, the combustion gas discharged to the combustion gas discharge pipe 73 is returned to the intake passage 14 through the three-way switching valve 86, and is introduced into the combustion chamber of the engine body 3 together with the intake air not introduced into the combustion heater 91. The mixture is supplied and formed with fuel injected from a fuel injection valve (not shown) to be burned (see solid arrow in FIG. 1). At this time, the combustion gas of which the temperature has been lowered due to heat exchange with the cooling water in the combustion heater 91 is supplied to the combustion chamber of the engine body 3, so that the intake air of high temperature is sucked for a long time. The heat damage to the engine 1 is prevented. Furthermore, by supplying a small amount of combustion gas having a relatively high CO ₂ concentration to the combustion chamber of the engine body 3, the amount of NOx generated by combustion in the combustion chamber of the engine body 3 can be efficiently reduced. Further, the combustion gas discharged from the combustion heater 91 is recombusted in the combustion chamber of the engine body 3, and the exhaust gas discharged from the combustion chamber of the engine body 3 is purified by the catalytic converter 39. Therefore, the combustion gas discharged from the combustion 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.
Since it does not flow into the compressor 15a of the turbocharger 15 and the intercooler 19 since it flows out to the above, heat damage to these is also prevented.

Next, when warming up the catalytic converter 39, when performing a process for recovering the catalytic converter 39 from SOx poisoning and SOF poisoning (hereinafter, referred to as poisoning recovery process), and the catalytic converter. When it is necessary to raise the temperature of the catalytic converter 39 during the reduction process for the 39 or the like, the valve body 80 opens the opening 79a by the operation of the valve device 78 as shown in FIG. The outlet 65 is opened, and the three-way switching valve 86 is controlled to close the intake passage 14 side.

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

Subsequently, the mixture of the intake air supplied to the combustion cylinder 40 by the rotary fan 90 and the fuel supplied from the fuel introduction passage 88 into the combustion cylinder 40 is energized by energizing the glow plug of the combustion cylinder 40. It is ignited by the glow plug and 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 air flow generated by the rotation of the rotary 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).

Since the combustion gas flowing through the combustion gas discharge port 65 hardly exchanges heat with the engine cooling water, it is considerably hotter than the combustion gas discharged from the combustion gas discharge port 63.

Then, this high temperature combustion gas reaches the three-way switching valve 86, and the intake passage 14 side is closed and the branch pipe 84 side is opened in the three-way switching valve 86, so that it flows into the branch pipe 84 and upstream of the catalytic converter 39. From the connection point C3 to the exhaust passage 42 (see the dashed arrow in FIG. 1).

The combustion gas of the combustion type heater 91 discharged to the connection point C3 of the exhaust passage 42 is the engine body 3 here.
The exhaust gas is mixed with the exhaust gas flowing through the exhaust passage 42, and as a result, the temperature of the exhaust gas is raised, and the exhaust gas flows into the catalytic converter 39 together with the exhaust gas to raise the temperature thereof.

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

Here, while the engine 1 is operating, the exhaust gas pressure in the exhaust passage 42 upstream of the catalytic converter 39 increases, but the combustion air of the combustion heater 91 is supplied from the downstream of the compressor 15a of the turbocharger 15. As a result of the intake, the combustion gas pressure of the combustion heater 91 can be made higher than the exhaust gas pressure in the exhaust passage 42 at the connection point C3 by utilizing the supercharging pressure of the turbocharger 15, so that the engine 1 is operated. The combustion gas of the combustion heater 91 can be discharged to the exhaust passage 42 upstream of the catalytic converter 39. Further, even when supercharging is performed by the turbocharger 15, backflow of exhaust gas does not occur in the combustion tube 40 of the combustion heater 91, and misfire due to backfire can be prevented.

Further, the combustion gas discharged from the combustion heater 91 flows out into the exhaust passage 42 between the HC adsorbent 38 and the catalytic converter 39 downstream of the turbine 15b of the turbocharger 15, so that the turbocharger 1
5, exhaust manifold 28, HC adsorbent 38
Since it does not flow through the above, and is not cooled in these, combustion gas having a high temperature can be utilized for heating the catalytic converter 39 by the amount that is not cooled, and the catalyst temperature can be efficiently raised.

Further, the combustion gas discharged from the combustion type heater 91 is the compressor 15 of the turbocharger 15.
Since it does not flow through a and the intercooler 19, it is possible to prevent the heat damage.

[0079]

As described above, according to the internal combustion engine having the combustion heater according to the present invention, the combustion gas of the combustion heater can be introduced between the HC adsorbent and the NOx catalyst. It is possible to prevent deterioration of the HC emission of the exhaust gas during the catalyst warm-up and after the catalyst warm-up, and it is possible to discharge the exhaust gas as a low HC concentration exhaust gas.

[Brief description of 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 sectional view showing an operating state of a combustion heater.

FIG. 3 is a cross-sectional view showing another operating state of the combustion heater.

[Explanation of symbols]

1 ... Engine (internal combustion engine) 3 ... Engine 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 22 ... Intake manifold 28 ... Exhaust manifold 30 ... EGR valve 37 ... Cooling water passage inside the heater 37a ... Cooling water inlet 37b ... cooling water outlet 38 ... HC adsorbent 39 ... Catalytic converter (NOx catalyst) 40 ... Combustion tube 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 outlet 65 ... Combustion gas outlet 71 ... Air supply pipe (air supply path) 73 ... Combustion gas exhaust pipe (combustion gas exhaust passage) 74 ... Connection pipe 78 ... Valve device 79 ... valve chamber 80 ... Valve 81 ... 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 ... Rotating fan 91 ... Combustion type heater 92 ... Motor 93 ... Housing 95 ... Air intake C1 ... Connection point between air supply pipe 71 and intake passage 14 C2 ... Connection point between combustion gas exhaust pipe 73 and intake passage 14 C3 ... Connection point between the exhaust passage 14 and the branch pipe 84 F ... Flame S ... Internal space of housing 93 W ... Heat carrier circuit W1 ... Cooling water introduction passage W2 ... Cooling water discharge channel W3 ... Cooling water discharge channel

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI F02M 31/06 F02M 31/06 Z (58) Fields investigated (Int.Cl. ⁷ , DB name) F01N 3/08-3 / 36 F02M 31/06

Claims (3)

(57) [Claims] Claim: What is claimed is: 1. Combustion air is introduced from an intake passage of an internal combustion engine, mixed with fuel, and the heat of combustion gas produced by burning the mixture in a combustion chamber is used to heat up engine-related elements. In an internal combustion engine having a combustion type heater, an HC adsorbent provided in an exhaust passage of the internal combustion engine, a NOx catalyst provided in the exhaust passage downstream of the HC adsorbent, and a cylinder of the internal combustion engine bypassed And a combustion gas exhaust passage for introducing the combustion gas between the HC adsorbent and the NOx catalyst, the internal combustion engine having a combustion heater. 2. A supercharger for boosting the intake air in the intake passage, and an air supply passage for introducing the intake air boosted by the supercharger as the combustion air. An internal combustion engine having the combustion heater according to 1. 3. A combustion gas in which the intake gas passage and the combustion gas discharge passage downstream of a connection point with the air supply passage introduce the combustion gas into an exhaust passage or an intake passage selectively. An internal combustion engine having a combustion heater according to claim 2, wherein the internal combustion engine is connected via a path switching means.