JP3514119B2 - 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 heater, and more particularly to an internal combustion engine having a combustion heater for introducing combustion gas into an intake system of the internal combustion engine in order to accelerate warming of the internal combustion engine. .

[0002]

2. Description of the Related Art For example, in Japanese Unexamined Patent Publication (Kokai) No. 62-75069, the engine cooling water is warmed by using high-temperature combustion gas produced by a combustion type heater installed in an intake passage of an internal combustion engine, whereby the internal combustion engine during cold weather. It shows the technology to improve the startability of the vehicle and promote warm-up.

The combustion type heater described in this publication is attached to the intake passage through an intake duct and an exhaust duct. Then, the air required for combustion of the combustion type heater is supplied from the intake passage of the internal combustion engine via the intake duct, and the combustion gas of the combustion type heater is discharged to the intake passage via the exhaust duct. And the high-heated combustion gas emitted by the combustion heater is
The structure is such that the engine cooling water in the water jacket of the internal combustion engine body is warmed after passing through the intake passage. Further, in the intake passage, between the connection point with the intake duct and the connection point with the exhaust duct, there is a so-called intake throttle valve that opens and closes the intake passage. This intake throttle valve
Before starting the internal combustion engine, it is fully closed, and for a while after starting,
The amount of combustion air supplied to the combustion heater is adjusted by half-closing (half-opening) or fully opening. By properly performing this adjustment, it is possible to promote warm-up of the internal combustion engine and improve startability. Then, the combustion gas of the combustion type heater eventually enters the cylinder of the internal combustion engine as the combustion air of the internal combustion engine through the intake duct and the intake passage.

[0004]

Although there is no description in the above-mentioned prior art, it is conceivable to equip the exhaust system of the internal combustion engine with a catalytic converter as an exhaust purification means. In order for the catalyst of a catalytic converter to work effectively, it must be raised to a temperature at which it works. Then, the catalyst temperature of the catalytic converter is usually raised by the heat of the exhaust gas emitted from the internal combustion engine. However, since the catalytic converter is provided in the exhaust system, the internal combustion engine is stopped as described above, and therefore, while the intake port and / or the exhaust port is closed, the exhaust gas of the internal combustion engine is stored in the catalytic converter. Not flowing. Therefore, the internal combustion engine must be started for the catalytic converter to function effectively. For this reason,
Since the catalytic converter cannot be warmed up before the internal combustion engine starts, it is considered that the catalytic converter may not function effectively even after the internal combustion engine starts. Although there is no description of a catalyst in the above-mentioned conventional technology, even if a catalytic converter is present, the combustion gas of the combustion heater is cooled by the cooling water of the cylinder head, so that high temperature combustion gas is not supplied to the catalyst. In addition, the combustion gas is discharged to the exhaust manifold by installing a special pipe, which causes a problem that the structure becomes complicated and the cost increases.

The present invention has been made in view of the above circumstances, and has a combustion heater so as to promote warm-up of the internal combustion engine and improve startability thereof, and exhaust gas for purifying exhaust gas of the internal combustion engine. In an internal combustion engine in which a catalytic converter is provided in the system, the catalytic converter is made to function effectively even at least when the internal combustion engine is in a stopped state before the internal combustion engine is started, and the exhaust gas purification of the combustion heater and the internal combustion engine are thereby performed. It is a technical object to provide an internal combustion engine having a combustion type heater, which can effectively purify exhaust gas and is inexpensive because of its simple structure.

[0006]

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

(1) In an internal combustion engine having a combustion heater in the intake passage of the internal combustion engine for promoting warm-up and improving startability of the internal combustion engine, the exhaust gas of the internal combustion engine is provided in the exhaust passage of the internal combustion engine. A catalytic converter to be purified, a portion of the intake passage that is downstream of the combustion heater installation location and an portion of the exhaust passage that is upstream of the catalytic converter installation location are connected to the cylinder of the internal combustion engine in a bypass manner. EGR that recirculates the exhaust gas of the internal combustion engine from the exhaust passage to the intake passage as its original function
A passage, and when the internal combustion engine is in a predetermined stop state and it is necessary to operate the combustion heater, the E
Combustion gas emitted from the combustion heater is sent from the intake passage to the exhaust passage via a GR passage.

Here, the "combustion heater" may be operation-controlled so as to be driven not only when the internal combustion engine is stopped but also when the internal combustion engine is in a predetermined operating state.
“When the internal combustion engine is in a predetermined operating state” means −10 ° C.
When the internal combustion engine is operating, after the internal combustion engine is started, or when the amount of heat generated by the internal combustion engine itself is small (for example, fuel (When the consumption is low) and when the amount of heat received by the internal combustion engine is small and the amount of heat received by the cooling water is small, or when the temperature of the cooling water is low immediately after starting at room temperature higher than 15 ° C. When there is an internal combustion engine, it is also "when it is necessary to operate the combustion heater". Then, when it is necessary to operate the combustion heater, the combustion heater operates to emit combustion gas.

It is a computer that controls the entire internal combustion engine, that is, E, to judge that these requirements are met.
CPU (Central Processing Unit), which is the center of CU (Engine Control Unit)
The CPU provided in the combustion type heater performs the operation control of the internal combustion engine and the combustion state control of the combustion type heater based on the determination.

"The internal combustion engine is in a predetermined stop state" means a stop state before the internal combustion engine starts to operate. For example, the internal combustion engine is not in the cranking state yet, but the driver This is a state in which the switch of the system is activated and therefore the combustion heater can be driven.

In the present paragraph (1), originally, the EGR passage serving as an exhaust gas recirculation passage for recirculating exhaust gas of the internal combustion engine from the exhaust passage to the intake passage is provided, and the internal combustion engine is in a predetermined stop state. Therefore, when it is necessary to operate the combustion heater, the combustion gas emitted by the combustion heater is sent from the intake passage to the exhaust passage via the EGR passage. And the exhaust port is still closed, even when the internal combustion engine is stopped,
The combustion gas of the combustion heater flows through the EGR passage to the exhaust passage of the internal combustion engine.

Therefore, even when the internal combustion engine is stopped, the high-heat combustion gas of the combustion type heater is used for the existing EGR.
Since the passages are used to flow to the catalytic converter in the exhaust passage, when the internal combustion engine is operating, the catalytic converter can already be warmed to a temperature at which it can function effectively. Therefore, after the start of the internal combustion engine, the purification performance of the catalytic converter can be sufficiently enhanced. In addition, since the existing EGR passage is used, the structure is simple and the cost can be reduced.

(2) In the above (1), the EGR passage is provided with an EGR valve for controlling the flow of the circulating gas passing through the EGR passage. The EGR valve burns when the internal combustion engine is in the predetermined stop state. The heater can also be opened when it needs to be activated.

In the item (2), since the EGR valve is provided in the EGR passage, the amount of circulating gas flowing through the EGR passage can be easily controlled. Therefore, when the temperature of the combustion gas emitted from the combustion heater is too high and there is a risk of causing heat damage to the catalytic converter, such an adverse effect can be prevented by increasing the throttle amount of the EGR valve.

Further, since the EGR valve is opened when the internal combustion engine is in the predetermined stop state and it is necessary to operate the combustion heater, it is necessary to drive the internal combustion engine and operate the combustion heater. At some point it can be closed.

(3) In (2), the combustion heater has an air supply path for supplying combustion air to the combustion chamber, and a combustion gas for discharging combustion gas generated in the combustion chamber from the combustion chamber. An exhaust passage, the combustion heater is connected to the intake passage through the air supply passage and the combustion gas discharge passage, and a connection point between the intake passage and the air supply passage in the intake passage and the intake passage. An intake throttle valve that throttles the intake passage is provided between a connection point between the combustion exhaust gas passage and the combustion gas discharge passage, and the intake throttle valve needs to operate the combustion heater when the internal combustion engine is in the predetermined stop state. The intake passage may be throttled when there is.

Here, the "intake throttle valve" throttles the intake passage when the internal combustion engine is in the predetermined stop state and needs to operate the combustion type heater, but opens after the internal combustion engine is started. You can also In this way, the output amount of the internal combustion engine is also controlled by controlling the intake air amount in the intake passage. Further, by performing the throttle operation of the intake throttle valve during the operation of the internal combustion engine, it is also useful for actively stopping the internal combustion engine. The intake throttle valve is also an ECU
The CPU controls its operation. In this section (3), when the combustion heater operates and the combustion gas comes out of the combustion heater, the combustion gas reaches the intake passage through the combustion gas discharge passage. At this time, the intake passage is throttled by the intake throttle valve. Therefore, the intake throttle valve comes to block the intake passage at the boundary. Therefore, the combustion gas of the combustion heater does not flow from the combustion gas discharge passage side of the intake passage toward the air supply passage side of the intake passage. At this time, since the EGR valve in the EGR passage is open as described above,
All the combustion gas of the combustion heater flows through the EGR passage to the exhaust passage of the internal combustion engine. Therefore, the catalytic converter provided in the exhaust passage can be efficiently warmed in advance before starting the internal combustion engine.

(4) In the above item (3), it is preferable that no supercharger is installed in the intake passage downstream of the connection between the intake passage and the combustion gas discharge passage. That is, the installation location in the intake passage of the supercharger is upstream of the connection location between the intake passage and the combustion gas discharge passage in the intake passage.

In the item (4), after the combustion gas emitted from the combustion type heater reaches the intake passage via the connection point with the combustion gas discharge path, the combustion gas is discharged from the supercharger downstream of the connection point. It doesn't hit this supercharger. Therefore, the heat of the combustion gas is not dispersed in the intake passage. Therefore, a large amount of combustion gas reaches the exhaust passage via the EGR passage, and therefore the catalytic converter in the exhaust passage can be sufficiently warmed.

(5) In the above item (3), an intercooler may not be installed in the intake passage downstream of the connection between the intake passage and the combustion gas discharge passage. That is, the installation location of the intercooler in the intake passage is upstream of the connection location of the intake passage and the combustion gas discharge passage in the intake passage.

Also in the case of this item (5), since the flow of the combustion gas does not hit the intercooler as in the case of the above item (4), the heat of the combustion gas is not dispersed. Therefore, a large amount of combustion gas reaches the exhaust passage via the EGR passage, so that the catalytic converter can be sufficiently warmed.

(6) In the above (1) or (2),
A supercharger and / or an intercooler is installed downstream of a connection point between the intake passage and the combustion gas discharge passage in the intake passage, and the internal combustion engine is in the predetermined stop state and the combustion heater It is also possible to have an introduction path for guiding the combustion gas of the combustion type heater downstream of the supercharger installation location and / or the intercooler installation location in the intake passage when it is necessary to operate.

In the item (6), when the combustion heater operates to generate combustion gas, the combustion gas is introduced to the intake passage downstream of the supercharger installation location and / or the intercooler installation location by the introduction passage. Be guided. Therefore, even if a supercharger or / and an intercooler is installed in the intake passage downstream of a connection point between the intake passage and the combustion gas discharge passage, the combustion gas is not provided in the supercharger or / and the intercooler. Does not hit, the same operational effect as described in the above (4) and (5) is obtained. Further, since the combustion gas of the combustion heater is guided to the downstream side of the supercharger installation location and / or the intercooler installation location in the intake passage by the introduction path, the flow of the combustion gas in the combustion gas discharge path is substantially reduced. That is, the combustion gas does not flow into the intake passage from the connection point of the combustion gas discharge passage with the intake passage. Therefore, in the intake passage, the combustion gas of the combustion heater does not flow from the connection point with the combustion gas discharge path toward the connection point with the air supply path. That is, no backflow occurs. And even in this case E
Since the EGR valve in the GR passage is open, all the combustion gas of the combustion heater flows through the EGR passage to the exhaust passage of the internal combustion engine. Therefore, the catalytic converter provided in the exhaust passage can be preheated before starting the internal combustion engine.

(7) In (6), the combustion heater is an air supply path for supplying combustion air to the combustion chamber, and a combustion gas discharge for discharging combustion gas generated in the combustion chamber from the combustion chamber. An intake throttle for connecting the combustion heater to the intake passage via the air supply passage and the combustion gas discharge passage, and narrowing the intake passage when the internal combustion engine is in the predetermined stop state. A valve may be provided in the intake passage upstream of a connection point between the intake passage and the introduction passage.

In the item (7), when the internal combustion engine is in the predetermined stop state, the intake passage is throttled by the intake throttle valve. Further, the combustion heater operates to discharge the combustion gas from the combustion heater, and the combustion gas is guided to the introduction passage and reaches the intake passage. However, since the intake throttle valve is provided in the intake passage upstream of the connection point between this intake passage and the introduction passage and is closed there, the combustion gas that has reached the intake passage through the introduction passage is intake throttled. Since it is blocked by the valve, it does not flow toward the upstream side of the installation location of the intake throttle valve in the intake passage. Therefore, the combustion gas of the combustion type heater does not flow into each connection portion of the intake passage where this is connected to the combustion gas discharge path of the combustion type heater and the air supply path. Then, at this time, since the EGR valve of the EGR passage is opened as described above, the combustion gas of the combustion heater flows entirely into the exhaust passage of the internal combustion engine via the EGR passage. Therefore, the catalytic converter provided in the exhaust passage can be efficiently warmed in advance before starting the internal combustion engine.

(8) In the above (6) or (7),
The introduction path branches from the combustion gas discharge path, and the branch point is opened when the combustion type heater needs to be operated, whereby the combustion gas is introduced into the intake passage at the supercharger installation location. It is preferable to provide a valve device that guides downstream.

Here, as the "valve device", a three-way valve is suitable.

The three-way valve has its one port, the first port, connected to the exhaust outlet of the combustion chamber of the combustion type heater, and one of the remaining two ports, the second port, serves as the combustion gas discharge passage. , And the other third port is connected to the introduction path. That is, the three-way valve is located between the combustion heater, the combustion gas discharge passage, and the introduction passage. Then, when the internal combustion engine is in the predetermined stop state and it is necessary to operate the combustion type heater, a first port communicating with the exhaust outlet of the combustion type heater and a third port communicating with the introduction path are provided. The valve element of the three-way valve is designed to open so that and communicate with each other. In this case, when the combustion heater burns, the combustion gas is introduced into the introduction passage-the intake passage-
The catalytic converter in the exhaust passage is reached via the EGR passage, and as a result, the catalytic converter can effectively function before the internal combustion engine is started as described above.

When it is necessary to operate the combustion heater after the internal combustion engine has started, this time, the first port and the second port communicating with the combustion gas discharge passage communicate with each other. The valve of the three-way valve is designed to open.
In this case, it can also be said that the internal combustion engine is not in the predetermined stop state, that is, the internal combustion engine is operating and the combustion heater needs to be operated.

In the item (8), by using a three-way valve as the valve device, one combustion type heater can be used properly according to the operating state of the internal combustion engine, which is convenient.

The EGR passage that recirculates the exhaust gas of the internal combustion engine from the exhaust passage of the internal combustion engine to the intake passage has its original function, not when the internal combustion engine is cold-started, but rather when the internal combustion engine warms up. It's because. Therefore, EG
Since the R valve opens and the EGR passage performs its original function after the catalytic converter of the internal combustion engine has sufficiently warmed up, there is no problem even if the EGR passage is used for raising the temperature of the catalytic converter. Because I am using the equipment of
It can be said that this is a very preferable mode.

(9) In the above (8), the valve device closes the introduction passage and opens the combustion gas discharge passage after the internal combustion engine is started, whereby the combustion gas is discharged through the combustion gas discharge passage. You may make it guide | induced to an upstream of the supercharger installation location in the said intake passage via.

In this section (9), the term "after the internal combustion engine is started" means that the engine 1 has been warmed up sufficiently.
This is done because it is not necessary to directly send the combustion heat of the combustion heater to the internal combustion engine even though the engine 1 has been warmed up sufficiently.

(10) In the above (3), the EGR valve is operated after the start of the internal combustion engine to start the EGR.
The passage area may be closed and the intake throttle valve may be controlled to increase the passage area of the intake passage.

In the item (10), all the combustion gas of the combustion type heater can be used for improving the low temperature startability of the internal combustion engine.

(11) In the above (10), a valve device for closing the air supply passage of the combustion type heater is provided in the air supply passage, and the valve device is configured to positively stop the driving of the internal combustion engine. It may be operated when the front intake passage is throttled by a valve.

Here, the "valve device" includes a valve body that opens and closes the inlet of the air flow passage, a drive unit that drives the valve body to open and close, and a CPU that controls the operation of the drive unit. Say. The "driving unit" may include an opening / closing mechanism capable of opening / closing the valve body with an appropriate driving motor.

In the above item (11), if the front intake passage is throttled by the intake throttle valve in order to positively stop the driving of the internal combustion engine, the valve device of the air supply passage is activated to close the air supply passage. Through the combustion heater connected to the intake passage via the air supply passage and the combustion gas discharge passage, there is no escape area for the intake air flowing through the intake passage, and the intake air flowing through the intake passage is completely shielded. Therefore, it is possible to efficiently stop the driving of the internal combustion engine using the intake throttle valve.

Further, the amount of air flowing through the air supply passage of the combustion heater can be adjusted by the valve device. Therefore, at least when the combustion heater is operated, if the amount of the air flowing through the air supply passage is sufficiently reduced or set to 0 (zero) by the above adjustment, strong ventilation that does not allow ignition is obtained. There is no danger of this occurring in the room. Therefore, no strong wind is generated in the air flow passage, so that the combustion heater can be reliably ignited at one time. Further, since the ignition is reliable, not only the generation of white smoke can be prevented but also the generation of unpleasant odor due to the generation of unburned hydrocarbons can be sufficiently prevented.

[0040]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. <First Embodiment> A first embodiment of the present invention will be described with reference to FIGS. (Engine 1) The engine 1 as an internal combustion engine is a water-cooled type, and has an engine body 3 having a water jacket containing engine cooling water, and intake air for sending air required for combustion into a plurality of cylinders (not shown) of the engine body 3. It has a device 5, an exhaust device 7 for releasing exhaust gas into the atmosphere after combustion of the air-fuel mixture, and a vehicle interior heater 9 for warming the interior of the vehicle in which the engine 1 is mounted. (Intake device 5) The intake device 5 starts with an air cleaner 13 that takes in fresh air into the cylinder,
The intake port (not shown) is terminated. And in the meantime, the compressor 15a of the turbocharger 15 which is a supercharger, the intercooler 19, and the intercooler 1
An intake manifold 21 that distributes the air-fuel mixture that has passed through 9 to each of the cylinders is provided.

The constituent members of the intake device 5 are connected by a plurality of connecting pipes belonging to the intake pipe 23, which will be described below. (Intake Pipe 23) The intake pipe 23, which is composed of a plurality of connecting pipes, is a downstream connecting pipe that is in a pressurized state when the intake air entering the intake device 5 from the air cleaner 13 is forcibly pushed at the boundary of the compressor 15a. 27 and the upstream side connecting pipe 25 which is not so. (Upstream-side connecting pipe 25) The upstream-side connecting pipe 25 is a rod-like connecting pipe that connects the air cleaner 13 and the compressor 15a and extends in the left-right direction in FIG. (Downstream Connection Pipe 27) The downstream connection pipe 27 connects the compressor 15a and the intake manifold 21 in the form of an L-shaped main pipe 29 extending vertically in FIG. And a heater branch pipe 31 as a branch pipe. (Heater Branch Pipe 31) The heater branch pipe 31 includes a combustion heater 17 in the middle thereof, connects the upstream side end of the combustion heater 17 and the main flow pipe 29, and supplies air to the combustion heater 17. It comprises an air supply passage 33, a combustion gas discharge passage 35 connecting the downstream side end of the combustion heater 17 and the main pipe 29 and discharging the combustion gas of the combustion heater 17 to the main pipe 29. Further, regarding the connection points C1 and C2 of the air supply path 33, the combustion gas discharge path 35, and the main flow tube 29, the connection point C1 is located on the upstream side of the main flow tube 29 rather than the connection point C2. (Air Supply Path 33) A valve device 44 is provided near the combustion heater 17 in the air supply path 33 that connects the upstream end of the combustion heater 17 and the main flow pipe 29. (Valve Device 44) As shown in FIG. 2, the valve device 44 includes a valve body 44a that opens and closes the air supply passage 33, a drive motor 44b that opens and closes the valve body 44a, a drive motor 44b, and a valve body 44a. The drive motor 44b is controlled by a computer (not shown) of the ECU 46 (see FIG. 1) that controls the engine 1 as a whole, that is, the opening / closing mechanism 44c. In addition, the valve device 44 operates to close the valve body 44a when the main flow pipe 29 is throttled by the intake throttle valve 70 described later in order to positively stop the driving of the engine 1. (Combustion Gas Discharge Path 35) An exhaust gas cooler 84 is attached near the combustion heater 17 in the combustion gas discharge path 35 that connects the downstream side end of the combustion heater 17 and the main flow pipe 29. (Exhaust Gas Cooler 84) The exhaust gas cooler 84 cools the combustion gas emitted from the combustion heater 17. (Parts around the connection points C1 and C2) Further, the intercooler 1 is provided between the connection point C1 and the compressor 15a.
9 is installed, and an intake throttle valve 70 is provided between the connection point C1 and the connection point C2 in the main flow pipe 29. (Intercooler 19) The intercooler 19 cools air downstream of the installation location of the compressor 15a, which is received by the combustion heater 17 and the compressor 15a for warming the intake air in order to accelerate warm-up of the engine 1 and improve startability. . (Intake throttle valve 70) The intake throttle valve 70 is a C of the ECU 46.
Its operation is controlled by the PU. In addition, the intake throttle valve 7
0 narrows the main pipe 29 when the engine 1 is in a predetermined stop state and the combustion heater 17 needs to be operated, but can be opened after the engine 1 is started. here,
"When the engine 1 is in a predetermined stop state" means a stop state before the engine 1 starts to operate. Specifically, although the engine 1 is not in the cranking state yet, the driver is the electric system. When the switch is activated, the combustion heater can be driven. In addition,
Unless "engine 1 is in a predetermined stopped state" is specifically limited below, simply "engine 1 is in a stopped state".
Say.

The intake throttle valve 70 can control the output of the engine 1 by throttling the intake throttle valve 70 under such a condition. Further, it is also used for actively stopping the engine 1 by controlling the throttle of the intake throttle valve 70 during the operation of the engine 1.

The intake air that passes through the main flow pipe 29 is divided into an intake air that branches to the heater branch pipe 31 at the connection point C1 and an intake air that does not branch and flows directly to the main flow pipe 29 toward the downstream side. Then, the intake air branched into the heater branch pipe 31 enters the valve device 4
4 through the air supply passage 33-the combustion heater 17-the combustion gas discharge passage 35 provided with the exhaust gas cooler 84,
It returns to the mainstream pipe 29 at the connection point C2 and joins the intake air that has not branched. As a result, the temperature of the intake air entering the engine body 3 is increased. (Exhaust device 7) The exhaust device 7 has an exhaust port (not shown) of the engine body 3 as a start end, and an exhaust manifold 37, a turbine 15b of the turbocharger 15, and exhaust gas of the engine 1 between the exhaust port 7 and the muffler 41 at the end. A catalytic converter 39 for purifying the exhaust gas is provided on the exhaust pipe 42. (EGR device 88) The engine body 3 includes an EGR device 8 as an exhaust gas recirculation device for returning a part of exhaust gas to the intake system.
8 is provided. The EGR device 88 includes an EGR passage 90 that connects the exhaust manifold 37 of the exhaust pipe 42 and the intake manifold 21 of the intake pipe 23 to a cylinder (not shown) of the engine body 3 in a bypass manner. Further, the EGR passage 90 is provided with an EGR valve 92 that controls the amount of gas flowing through the EGR passage 90. EGR valve 9
2 is electrically connected to the CPU of the ECU 46, and
The GR device 88 basically functions as an exhaust gas recirculation device, and basically opens when the engine 1 warms up sufficiently, but operates the combustion heater 17 when the engine 1 is stopped. It is a variable controllable valve that opens when needed. Further, the EGR valve 92 is connected to a pressure control valve (not shown) for controlling the negative pressure of the EGR valve 92, such as the duty VSV. This pressure control valve receives a drive pulse signal having a duty ratio corresponding to the ratio of the fully open time and the fully closed time of the EGR valve 92, in other words, the open ratio of the EGR valve 92, from the CPU. According to EG
The R valve 92 is driven.

As described above, when the EGR device 88 is opened when the engine 1 is stopped and the combustion heater 17 needs to be operated, the combustion gas emitted from the combustion heater 17 is passed through the EGR passage 90. From the intake pipe 23 to the exhaust pipe 42
Send to.

The description of the EGR passage 90 can be rephrased as follows. That is, the EGR passage 90 is
It is a passage that connects a portion of the main flow pipe 29 of the intake pipe 23, which is downstream of the installation position of the combustion heater 17, and an upstream portion of the exhaust pipe 42, which is upstream of the installation position of the catalytic converter 39, to the cylinder in a bypass manner. . (Combustion Heater 17) The combustion heater 17 is controlled to be driven not only when the engine 1 is in a predetermined stop state but also when the engine 1 is in a predetermined operation state. "When the engine 1 is in a predetermined operating state" means that the temperature is around -10 ° C to 15 ° C during cold weather or -10 ° C.
When the engine 1 is running, or after the engine 1 is started, or when the amount of heat generated by the engine 1 itself is low (for example, when fuel consumption is low) during extremely cold weather, which is the following temperature
And when the amount of heat received by the cooling water is small due to the small amount of heat generated by the engine 1 itself, and further when the temperature of the cooling water is low immediately after starting at room temperature higher than 15 ° C. There are times when "combustion heater 17
When you need to work. " Combustion heater 1
It is the ECU 46 that determines when it is necessary to operate 7
If the CPU determines that it is necessary to operate the combustion heater 17, the combustion heater 17
Is activated and combustion gas is emitted from there.

For the sake of convenience, the condition under which the combustion heater 17 operates in a predetermined stop state of the engine 1 is referred to as "the preheating condition of the combustion heater is satisfied while the engine is stopped". The operation of the combustion heater 17 when the preheating condition of the combustion heater 17 is satisfied is referred to as preheating of the combustion heater. However, the preheat condition of the combustion heater 17 does not mean that the combustion heater 17 immediately starts combustion, and the combustion heater 17 described later in the stopped state of the engine 1 shown in FIG. The combustion heater 17 operates only after the operation start control is performed.

Next, the structure of the combustion heater 17 is schematically shown.

The combustion type heater 17 operates to raise the temperature of the engine cooling water when the engine 1 is in a predetermined operating state, and is therefore connected to the water jacket containing the engine cooling water. . Therefore, the combustion heater 17 is provided with a cooling water passage 17a through which the engine cooling water passes. The cooling water passage 17a is warmed by the combustion gas flowing through the combustion chamber 17d which is a heat source. (Combustion chamber 17d) The combustion chamber 17d has a combustion cylinder 17b therein.
And a combustion chamber 17b having a cylindrical shape.
Cover with c. By covering the combustion cylinder 17b with the partition wall 17c, the combustion chamber 17d is defined in the case body 43a of the combustion chamber body 43, and the inner surface of the case body 43a and the partition wall 17c are separated.
The cooling water passage 17a is formed between the cooling water passage 17a and the outer surface of the cooling water passage 17a.

The combustion chamber 17d also functions as an air passage in the heater. Therefore, the combustion chamber 17d includes the air supply passage 33 and the combustion gas discharge passage 35 of the combustion heater 17, the air supply port 17d ₁ and the exhaust gas discharge, respectively. It is connected at the exit 17d ₂ . Then, as described above, when the intake air branches from the main flow pipe 29 and passes through the heater branch pipe 31, the air supply passage 33-combustion chamber 17d-combustion gas discharge passage 35 is connected as shown by a solid arrow in FIG. The intake air containing the combustion gas returns to the main flow pipe 29 via. Since this intake air is warmed by the combustion heat of the combustion gas, the warmed intake air is discharged until the warmed intake air is discharged from the combustion chamber main body 43 through the path indicated by the solid line arrow. The cooling water flowing through the cooling water passage 17a is heated as a heat medium. Therefore, the combustion chamber 17d can be said to be a heat exchange passage. (Combustion cylinder 17b) Combustion fuel is supplied to the combustion cylinder 17b through a fuel supply pipe 17e serving as a fuel supply passage. When the combustion fuel is supplied from here to the combustion chamber 17d, this fuel is supplied to the combustion chamber main body. It vaporizes in 43. Then, this vaporized fuel is ignited by an ignition device (not shown), and the vaporized fuel burns. (Cooling water passage 17a) On the other hand, the cooling water passage 17a has a cooling water introduction port 17a1 and a cooling water discharge port 17a2, and the cooling water introduction port 17a1 is not shown in the engine body 3 as can be seen from FIG. It is connected to the cooling water discharge port of the water jacket via a water pipe W1.

The cooling water discharge port 17a2 is connected to the vehicle interior heater 9 via a water conduit W2. The vehicle interior heater 9 is connected to the cooling water introduction port of the water jacket of the engine body 3 via the water pipe W3.

Therefore, when the cooling water of the water jacket reaches the combustion type heater 17 via the water line W1, it is warmed there, and thereafter the water is cooled from the combustion type heater 17 to the water line W2.
To the heater 9 for the passenger compartment, and heat is exchanged as a heat medium of the heater 9 for the passenger compartment to emit warm air into the passenger compartment. The cooling water whose temperature has dropped due to heat exchange returns to the water jacket via the water pipe W3. In this way, the cooling water circulates among the engine body 3, the combustion heater 17, and the vehicle interior heater 9 via the water conduits W1 to W3. (Other Components of Combustion Heater 17) In addition to this, the combustion chamber main body 43 is provided with a blower fan 45 and a central processing control device belonging to an engine electronic control unit (ECU) not shown, by which the combustion heater 17 is provided. Works well,
A flame F is created in the combustion chamber 17d. (Others) Further, the air supply passage 33 and the combustion gas discharge passage 35 are tributaries of the main flow pipe 29 belonging to the intake pipe 23, but considering that they are applied only to the combustion heater 17, These tubes can be regarded as the constituent elements of the combustion heater 17.

Next, the operation control start execution routine of the combustion heater 17 will be described with reference to FIG. This routine is for operating the combustion heater 17 before driving the engine 1, and includes steps S101 to S105 described below. A flowchart of each step constituting this routine is stored in the ROM of the ECU 46. Further, the flow chart according to the second embodiment is also stored in the ROM of the ECU 46. And, the processing in each step of each flowchart is all EC
This is due to the CPU of U46.

The symbol S is used, for example, in step 10
If it is 1, it is abbreviated as S101.

First, in S101, it is determined whether the engine 1 is stopped and the preheat condition of the combustion heater 17 is satisfied. If an affirmative decision is made in S101, the routine proceeds to S102, and if a negative decision is made, this routine is ended.

At S102, the intake throttle valve 7 of the main flow pipe 29 is
0 is fully closed. As a result, the main flow pipe 29 is closed.

In S103, the valve device 44 of the air supply passage 33
The drive motor 44b is operated to activate the opening / closing mechanism 44c to open the valve element 44a. As a result, the heater branch pipe 31 as a tributary pipe including the combustion heater 17 connected in a bypass manner to the main flow pipe 29 is opened.

In S104, the EGR valve 92 of the EGR device 88 is fully opened. As a result, the EGR passage 90 is opened.

In step S105, the preheating of the combustion type heater 17 is started. <Operation and Effect of First Embodiment> Next, operation and effect when the engine 1 is in a predetermined stop state will be described.

When the combustion heater 17 operates, the air that has entered the intake device 5 from the air cleaner 13 reaches the exhaust device 7 along the following path. Upstream connecting pipe 25 from the air cleaner 13 to the intake pipe 23
The air that has entered the mainstream pipe 29 passes through the compressor 15 a of the turbocharger 15 and the intercooler 19.
Although it is originally directed to the intake throttle valve 70, since the intake throttle valve 70 is closed as described above, it flows from the connection point C1 to the air supply passage 33. The air that has entered the air supply path 33 is sent to the combustion chamber body 43 of the combustion heater 17 via the valve device 44. The air that has entered the combustion chamber body 43 is provided as combustion air for the combustion fuel sent from the fuel supply pipe 17e in the combustion chamber 17d of the combustion chamber body 43, and becomes combustion gas after combustion to the combustion gas discharge passage 35. Get out. The combustion gas discharged to the combustion gas discharge passage 35 enters the main flow pipe 29 from the connection point C2 of the main flow pipe 29 via the exhaust gas cooler 84. The combustion gas that has entered the main flow pipe 29 does not enter the cylinder of the engine body 3 because the engine 1 is stopped and the intake port and / or the exhaust port are closed, so that the intake manifold 21 and the exhaust manifold 37 are not provided.
To the catalytic converter 39 of the exhaust pipe 42 via the EGR passage 90 connecting them, and the catalytic converter 39 is warmed there.

As described above, the engine 1 is originally provided with the EGR device 88 including the EGR passage 90 and the EGR valve 92, which serves to recirculate the exhaust gas of the engine 1 from the exhaust pipe 42 to the intake pipe 23, When the engine 1 is stopped and the combustion heater 17 needs to be operated, the EG
Since the combustion gas emitted by the combustion heater 17 is sent from the intake pipe 23 to the exhaust pipe 42 via the R passage 90, the intake port and / or the exhaust port of the engine 1 are still closed. Also, the combustion gas of the combustion heater 17 flows to the catalytic converter 39 of the exhaust pipe 42 by using the EGR passage 90. Thus, when the engine 1 is operating, the catalytic converter 39 can already be raised to a temperature at which it can function effectively. Therefore, after the engine 1 is started, the catalytic converter 39
The purification performance of can be sufficiently enhanced. In addition to that,
Since the existing EGR passage is used, the structure is simple and the cost can be reduced.

Further, even when the engine is stopped, the high-heat combustion gas of the combustion heater 17 flows to the catalytic converter 39 of the exhaust pipe 42 via the EGR passage 90, so that the engine 1 enters the operating state from the stopped state. By the time, the catalytic converter 39 is already warmed to a temperature at which it can function effectively. Therefore, after the engine 1 is started, the purification of the exhaust gas emitted by the engine body 3 can be extremely effectively processed. In addition, the combustion gas emitted by the combustion heater 17 can be purified by the catalytic converter 39 both before and after the engine 1 is started.

Further, since the EGR passage 90 is provided with the EGR valve 92 for controlling the flow of the circulating gas passing therethrough, the amount of the circulating gas flowing through the EGR passage 90 can be easily controlled. Therefore, when the temperature of the combustion gas emitted from the combustion heater 17 is too high and may cause heat damage to the catalytic converter 39, such an adverse effect can be prevented by increasing the throttle amount of the EGR valve 92.

Furthermore, when the combustion heater 17 is activated to generate combustion gas from the combustion heater 17, the combustion gas reaches the main pipe 29 through the combustion gas discharge passage 35. At this time, the main pipe 29 sucks the intake air. Since it is throttled by the valve 70, the intake throttle valve 70 blocks the main flow pipe 29 of the intake pipe 23. Therefore, the combustion gas of the combustion heater 17 does not flow from the combustion gas discharge passage 35 side of the main flow pipe 29 toward the air supply passage 33 side. Since the EGR valve 92 of the EGR passage 90 is open at this time, all the combustion gas of the combustion heater 17 flows into the exhaust pipe 42 via the EGR passage 90. Therefore, the catalytic converter 39 provided in the exhaust pipe 42 can be efficiently warmed in advance.

In the intake pipe 23, the compressor 15a of the turbocharger 15 and the intercooler 19 are not installed downstream from the connection point C2 between the main flow pipe 29 and the combustion gas discharge passage 35. Therefore, the combustion heater 17
Combustion gas emitted from the connection point C with the combustion gas discharge passage 35
The combustion gas after reaching the mainstream pipe 29 via 2 does not hit the compressor 15a or the intercooler 19. Therefore, the heat of the combustion gas is not dispersed in the main flow pipe 29. Therefore, a large amount of combustion gas can be made to reach the exhaust pipe 42 via the EGR passage 90, so that the catalytic converter 39 in the exhaust pipe 42 can be sufficiently warmed.

Next, the case where the engine 1 is operated will be described.

In the operating state of the engine 1, the intake throttle valve 2
Although 9 is fully opened, the EGR valve 92 and the valve element 44a of the valve device 44 may be fully opened or fully closed. This differs mainly when the engine 1 is not warmed up yet and when it is already warmed up.
If the warm-up is still insufficient, the EGR valve 92 is closed and the valve element 44a is opened. By doing so, the high-temperature combustion gas of the combustion heater 17 enters the cylinder of the engine body 3, so that the engine 1 warms up.

When the latter engine 1 is sufficiently warmed up, the EGR valve 92 is opened and the valve element 44a is closed. This is because the engine 1 is warmed up sufficiently to execute the original exhaust gas recirculation of the EGR device 88.
This is because it is not necessary to open the valve body 44a and send the high-heated combustion gas emitted by the combustion heater 17 to the engine body 3 in spite of the sufficient warm-up of the engine. (Other functions and effects) In the first embodiment, the combustion heater 17 has the bypass shape with respect to the intake passage 29 in the order of the air supply passage 33, the combustion chamber body 43 and the combustion gas discharge passage 35. The compressor 15a of the turbocharger 15 and the intercooler 19 are not interposed between the connection point C1 with the air supply passage 33 and the connection point C2 with the combustion gas discharge passage 35 in the intake passage 29. That is, the combustion heater 17 is arranged downstream of the installation location of the compressor 15a. Therefore, excessive pressure does not occur on the side of the air supply passage 33 and the side of the combustion gas discharge passage 35 centering on the combustion chamber body 43 of the combustion heater 17. Therefore, the air velocity in the combustion chamber main body 43 connected to the main flow pipe 29 via the air supply passage 33 and the combustion gas discharge passage 35 does not become excessive. Therefore, there is no possibility of generating strong ventilation in the combustion chamber body 43 to the extent that the combustion heater 17 cannot be ignited.
Can be surely ignited.

Further, the air supply passage 33 in the main flow pipe 29.
Since there is no compressor 15a in the portion between the connection point C1 with and the connection point C2 with the combustion gas discharge passage 35,
The compressor 15a does not operate in this portion.
Therefore, the connection point C1 and the connection point C2 are connected to each other at the connection point C.
Only the pressure on the 2 side does not increase, and the pressure on the connection point C1 side does not decrease in comparison with that, and the pressures on both sides are substantially uniform. Therefore, backflow does not occur in the combustion chamber 17d of the combustion heater 17 connected to the main flow pipe 29 through the air supply passage 33 and the combustion gas discharge passage 35. Therefore, there is no occurrence of a flashback phenomenon in which the flame direction of the combustion heater 17 faces the air supply path 33 side, and as a result, a sufficient amount of heat can be obtained from the combustion heater 17 when the engine 1 is warmed up.

The air supply passage 33 of the combustion heater 17
Since the combustion gas discharge passage 35 is open to the main flow pipe 29 and not directly to the atmosphere, a noise reducing effect can be expected.

Further, while the engine 1 is in operation, in order to positively stop the driving of the engine 1, the intake throttle valve 70
When the main flow pipe 29 is narrowed by, the valve device 44 of the air supply passage 33 is actuated and the air supply passage 33 is closed by the valve element 44a as described in the section of the valve device 44. Therefore, the intake air flowing through the intake pipe 23 via the heater branch pipe 31 has no escape area, and the main flow pipe 29 has the intake throttle valve 70.
Since it is squeezed as described above, air cannot pass through it. Therefore, the intake air flowing through the entire intake pipe 23 is completely blocked. Therefore, the intake throttle valve 70
It is possible to efficiently stop the driving of the engine 1 using the.

Further, the air supply passage 33 of the combustion heater 17
The amount of air flowing through can be adjusted by the valve device 44. Therefore, at least when the combustion heater 17 is operated, if the amount of the air flowing through the air supply passage 33 is reduced sufficiently to zero so that it can be ignited or set to 0 (zero) by the adjustment, strong ventilation that does not ignite is burned. There is no risk of this occurring in the heater 17. Therefore, no strong wind is generated in the air flow passage 33, so that the combustion heater 17 can be reliably ignited at one time. Further, since the ignition is reliable, not only the generation of white smoke can be prevented but also the generation of unpleasant odor due to the generation of unburned hydrocarbons can be sufficiently prevented.

Further, since the combustion gas of the combustion-type heater 17 containing almost no smoke, in other words, containing no carbon, is used to promote warm-up, carbon does not adhere to the inner wall surface of the cylinder. It can be expected that the durability of the engine 1 will be improved. <Second Embodiment> The second embodiment will be described with reference to FIGS.

The second embodiment differs from the first embodiment in that the heater branch pipe 31 is connected by the upstream connecting pipe 25 instead of the main flow pipe 29.
A branch pipe 95 that extends downstream of the intake throttle valve 70 in the main flow pipe 29 is provided in the middle of the combustion gas discharge passage 35, and the combustion heater 17 is operated at the branch point of the branch pipe 95 in the combustion gas discharge passage 35. Since the three-way valve 97 as a valve device that is opened when necessary is provided and the valve device 44 is not provided, the same reference numerals are given to the other same portions and the description thereof will be omitted.

As shown in FIG. 4, by connecting the heater branch pipe 31 with the upstream connecting pipe 25, the combustion heater 17 and
The heater branch pipe 31 including the air supply passage 33 and the combustion gas discharge passage 35 serves as a U-shaped bypass passage located upstream of the compressor 15a. Therefore, the downstream side connecting pipe 27 described in the first embodiment is only the L-shaped main flow pipe 29 in the second embodiment. Further, the connection points where the air supply passage 33 and the combustion gas discharge passage 35 of the heater branch pipe 31 are connected to the upstream side connecting pipe 25 are shown by reference signs C1 and C2, respectively.

Further, since the branch pipe 95 branched from the combustion gas discharge passage 35 extends downstream of the intake throttle valve 70, the branch pipe 95 is provided downstream of the intake throttle valve 70 and downstream of the intercooler 19 and the compressor 15a. The tip of 95 comes to be located. Therefore, when the combustion heater 17 is operated to burn the combustion fuel when it is necessary to operate the combustion heater 17, the combustion gas emitted at that time is intercooled in the intake pipe 23 via the branch pipe 95. It will be guided downstream from the 19 installation points. Therefore, the branch pipe 9
Reference numeral 5 is a compressor 15a for the combustion gas of the combustion type heater 17.
It can be said that it is an introduction pipe (introduction path) that leads downstream from the intercooler 19.

On the other hand, the three-way valve 97 has a structure as shown in FIG.

The three-way valve 97 has its one port, the first port 97a, connected to the exhaust outlet 17d ₂ of the combustion heater 17, and one of the remaining two ports, the second port 97b, is connected to the combustion gas. The discharge path 35 and the other third port 97c are connected to the branch pipe 95. That is, the three-way valve 97 is located between the combustion heater 17, the combustion gas discharge passage 35, and the branch pipe 95. Inside the case body 97a of the three-way valve 97, there is provided a valve body 98 which moves in the longitudinal direction of the case body 97a by the operation of a diaphragm (not shown). This valve body 98
Depending on the moving position of the valve body 98 in the case body 37a, two of the three mouths, that is, the first mouth 97.
a and the second mouth 97b, or the first mouth 97a and the third mouth
Communication with the mouth 97c. And in that case, the first
When the second mouth 97a and the second mouth 97a communicate with each other,
The third mouth 97c is closed and the first mouth 97a and the third mouth 97c are closed.
When communicating with c, the second port 97b is closed.

More specifically, when the engine 1 is stopped and the combustion heater 17 needs to be operated, the first
The valve body 9 so that the mouth 97a and the third mouth 97c communicate with each other.
8 moves. In this case, when the combustion heater 17 burns,
The combustion gas emitted at that time is the branch pipe 95-main flow pipe 29-E.
It reaches the catalytic converter 39 of the exhaust pipe 42 via the GR passage 90, and therefore the catalytic converter 39 functions effectively before the engine 1 is started.

Next, the operation control start execution routine of the combustion heater 17 will be described based on FIG. 6 when the engine 1 is in the stopped state and when it is not. This routine consists of steps S201 to S215 described below.

First, in S201, it is determined whether the engine 1 is stopped. If a positive determination is made in S201, S20
If the determination is negative, the procedure proceeds to S203.

In S202, it is determined whether or not the preheat condition of the combustion type heater 17 is satisfied. S202
If the determination is affirmative, the process proceeds to S204, and if the determination is negative, the routine ends.

At S204, the intake throttle valve 70 of the main flow pipe 29 is
Fully close. As a result, the main flow pipe 29 is closed.

In S206, the position of the valve element 98 of the three-way valve 97 is moved to the position shown by the solid line in FIG. 5 to connect the first port 97a and the third port 97c of the three-way valve 97. By doing so, a flow path for flowing the exhaust combustion gas of the combustion heater 17 to the branch pipe 95 is formed in the case body 97a of the three-way valve 97 (see the solid line arrow in FIG. 5).

At S207, the EGR valve 9 of the EGR device 88 is
Fully open 2. As a result, the EGR passage 90 is opened.

In S208, the operation of the combustion heater 17 is executed when the engine 1 is in a stopped state, and the operation of the combustion heater 17 is started with the preheat execution state of the combustion heater 17 set as a target.

Returning to S201, the case where the operation of the combustion heater 17 is executed when the engine 1 is not in the stopped state, that is, when the negative determination is made in S201 will be described in each step of S203 and subsequent steps.

In S203, it is determined whether the engine 1 has started and is in the cranking state. It is determined whether the engine 1 is warmed up sufficiently by the determination here. If an affirmative decision is made in S203, the operation proceeds to S209, and if a negative decision is made, the operation proceeds to S210.

In S209, the EGR valve 92 is fully closed, and the EG
The R passage 90 is closed.

In S211, the intake throttle valve 70 is fully opened to increase the passage area of the intake passage.

In S213, the position of the valve element 98 of the three-way valve 97 is moved to the position shown by the solid line in FIG. 5 to connect the first port 97a and the third port 97c of the three-way valve 97. By doing so, a flow path can be formed in the three-way valve 97 to allow the exhaust combustion gas of the combustion heater 17 to flow to the branch pipe 95 (see the solid arrow in FIG. 5). After that, the routine proceeds to S208, where the operation of the combustion heater 17 during cranking is started, and then the operation of the combustion heater 17 for the purpose of making the flame size desired by the CPU is started.

The process returns to S203.

The case of making a negative determination in S203 and proceeding to S210 means that the warm-up of the engine 1 has been satisfied to some extent. In S210, the position of the valve element 98 of the three-way valve 97 is moved to the position shown by the chain double-dashed line in FIG. 5 to connect the first port 97a and the second port 97b of the three-way valve 97.
By doing so, a flow path for flowing the combustion gas of the combustion heater 17 toward the connection point C2 of the upstream side connecting pipe 25 can be formed in the case body 97a of the three-way valve 97 (see the double-dashed line arrow in FIG. 5). ).

At S214, the original role of the EGR device 88 is executed. That is, the exhaust gas of the engine 1 is exhausted from the exhaust pipe 4
Recirculate from 2 to the intake pipe 23. For convenience, EG
We will call it R control execution.

In S215, in order to stop the engine, reduce the intake noise, and facilitate the recirculation of the exhaust gas of the engine 1 from the exhaust pipe 42 to the intake pipe 23 by executing the EGR control of S213. The throttle control of the intake throttle valve 70 is performed. This is called intake throttle valve control execution for convenience.
After that, the routine proceeds to S208, where the operation of the combustion heater 17 is started when the warm-up of the engine 1 is satisfied to some extent, and the combustion heater 17 for the purpose of adjusting the flame size to the desired one by the CPU. Enter the execution of. . <Operation and Effect of Second Embodiment> The second embodiment has the following operation and effect.

First, the operation and effect when the engine 1 is stopped will be described.

When the combustion heater 17 operates, the air that has entered the intake device 5 from the air cleaner 13 follows the following path to reach the exhaust device 7. Upstream connecting pipe 25 from the air cleaner 13 to the intake pipe 23
The air that has entered the mainstream pipe 29 passes through the compressor 15 a of the turbocharger 15 and the intercooler 19.
Although it is originally directed to the intake throttle valve 70, since the intake throttle valve 70 is closed as described above, it flows into the air supply passage 33 at the connection point C1. The air that has entered the air supply path 33 is sent to the combustion chamber body 43 of the combustion heater 17 via the valve device 44. The air that has entered the combustion chamber body 43 is provided as combustion air for the combustion fuel that is sent from the fuel supply pipe 17e in the combustion chamber 17d of the combustion chamber body 43, and becomes combustion gas after combustion to form the combustion gas exhaust passage 35. Heading to the three-way valve 97 provided at the branch point of the branch pipe 95. At this time, the three-way valve 97 is S206 of the flowchart.
In this state, the combustion gas proceeds through the branch pipe 95 and enters the main flow pipe 29 downstream of the intake throttle valve 70. Since the engine 1 is stopped and the intake port and / or the exhaust port are closed, the combustion gas that has entered the main flow pipe 29 passes through the intake manifold 21 and EG.
Enter the R passage 90. At this time, since the EGR valve 92 is open, the EGR valve 92 reaches the exhaust manifold 37 via the EGR passage 90, and then enters the exhaust pipe 42. After that, it reaches the catalytic converter 39 of the exhaust pipe 42 and warms the catalytic converter 39.

Also in the case of the second embodiment, as in the first embodiment, the combustion gas emitted from the combustion heater 17 is sent from the intake pipe 23 to the exhaust pipe 42 via the EGR passage 90. The combustion gas of the combustion heater 17 flows to the exhaust pipe 42 via the EGR passage 90 even when the engine 1 is in a stopped state in which the intake port and / or the exhaust port of the engine 1 are still closed. Therefore, even if the combustion heater 17 is operated and the combustion gas is discharged from the engine 1 when the engine 1 is stopped, the combustion gas of the combustion heater 17 does not fill the intake pipe 23. Therefore, the high heat of the combustion gas of the combustion heater 17 does not cause heat damage to the intake system structure. In addition to this, as described in the first embodiment, the catalytic converter 39 can be preheated before the engine 1 is started, or the exhaust gas emitted from the engine body 3 can be purified after the engine 1 is started. It has an effect that it can be processed very effectively.

When it is necessary to operate the combustion heater 17 when the engine 1 is in a predetermined stopped state, the branch pipe 9
Since the combustion gas of the combustion heater 17 is guided to the downstream side of the intake pipe 23 from the location where the compressor 15a is installed and the location where the intercooler 19 is installed, the combustion heater 17
Is activated to generate combustion gas, the combustion gas is discharged from the branch pipe 95.
Thus, the intake pipe 23 is guided downstream of the installation location of the compressor 15a and / or the installation location of the intercooler 19. Therefore, the combustion gas bypasses the compressor 15a and the intercooler 19 and does not hit them, so that the heat of the combustion gas is not dispersed in the intake passage. Therefore, a large amount of combustion gas is supplied to the EGR passage 9
It is possible to reach the exhaust pipe 42 via 0 and sufficiently heat the catalytic converter 39 there.

Further, the branch pipe 95 allows the combustion gas of the combustion heater 17 to pass through the compressor 15 of the intake pipe 23.
a and the location where the intercooler 19 is installed, so that the flow of the combustion gas in the combustion gas discharge passage 35 is substantially interrupted, and the connection point of the combustion gas discharge passage 35 with the upstream side connecting pipe 25 becomes the same. From C2 upstream connection pipe 2
It becomes the same when the combustion gas does not flow into 5. Therefore,
In the intake pipe 23, the combustion gas of the combustion heater 17 does not flow from the connection point C2 with the combustion gas discharge path 35 toward the connection point C1 side with the air supply path 33. That is, no backflow occurs. Even in this case, since the EGR valve 92 of the EGR passage 90 is open, the combustion heater 1
The combustion gas of No. 7 flows to the exhaust pipe 42 via the EGR passage 90. Therefore, the catalytic converter 39 provided in the exhaust pipe 42 can be efficiently warmed in advance. Next engine 1
The case of operating is described.

During cranking when the engine 1 is not warmed up sufficiently, the EGR valve 92 is closed and the three-way valve 97 is opened so that the combustion gas of the combustion heater 17 flows to the branch pipe 95 side. By doing so, the combustion heater 1
Since the hot combustion gas 7 enters the cylinder of the engine body 3, the engine 1 warms up.

When the engine 1 is warmed up sufficiently, the EGR valve 92 is opened and the combustion heater 17 is opened.
The three-way valve 97 is opened so that the combustion gas of (3) flows to the combustion gas discharge passage 35 side (see the broken line arrow in FIG. 5). This is because the engine 1 is sufficiently warmed up so that the exhaust gas recirculation originally performed by the EGR device 88 is executed, and even though the engine 1 is sufficiently warmed up, the high-heat combustion gas produced by the combustion heater 17 is generated. Is not required to be directly sent to the engine body 3.

The EGR passage 9 which is an exhaust gas recirculation passage
The original function of 0 works not when the engine 1 is cold started, but after warming up of the internal combustion engine to some extent. Therefore, the EGR valve 92 is opened, and the EGR passage 90 performs its original function in the catalytic converter 39 of the internal combustion engine.
Since it has been sufficiently warmed up, there is no problem even if the EGR passage 90 is used for raising the temperature of the catalytic converter 39, and rather the existing equipment is used, which is a very preferable mode.

Furthermore, after starting the engine 1, the EG
Since the R valve 92 is operated to close the EGR passage 90 and the intake throttle valve 70 is controlled to throttle the intake pipe 23, all the combustion gas of the combustion heater 17 can be used for improving the low temperature startability of the engine 1.

[0104]

As described above, according to the present invention, a combustion type heater is provided so as to promote warm-up and startability of an internal combustion engine, and a catalytic converter is provided in an exhaust system for purifying exhaust gas of the internal combustion engine. In the internal combustion engine equipped with, at least when the combustion type heater is operated when the internal combustion engine is in a stopped state before starting the operation, heat damage to the intake system structure is prevented, and Even before the internal combustion engine is started, the catalytic converter can be effectively operated, and the exhaust gas of the combustion heater and the exhaust gas of the internal combustion engine can be effectively purified.

[Brief description of drawings]

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

FIG. 2 is a schematic sectional view of a combustion heater.

FIG. 3 is a routine for starting operation control of the combustion heater according to the first embodiment.

FIG. 4 is a schematic configuration diagram of a second embodiment of an internal combustion engine having a combustion heater according to the present invention.

FIG. 5 is a schematic explanatory diagram of a valve device that is a three-way valve.

FIG. 6 is a routine for starting operation control of a combustion heater according to a second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine) 3 ... Engine main body 5 ... Intake device 7 ... Exhaust device 9 ... Cabin heater 13 ... Air cleaner 15 ... Turbocharger (supercharger) 15a ... Compressor 15b ... Turbocharger turbine 17 ... Combustion type heater 17a ... cooling water passage 17a ₁ ... cooling water inlet 17a ₂ ... cooling water discharge port 17b ... combustion cylinder 17c ... cylindrical partition wall 17d ... combustion chamber 17d ₁ ... air supply port 17d ₂ ... exhaust outlet 17e of the combustion heater ... Fuel supply pipe 19 ... Intercooler 21 ... Intake manifold 23 ... Intake pipe 25 ... Upstream connecting pipe 27 ... Downstream connecting pipe 29 ... Main flow pipe (intake passage) 31 ... Heater branch pipe 33 ... Air supply passage 35 ... Combustion Gas exhaust path 37 ... Exhaust manifold 39 ... Catalytic converter 41 ... Muffler 42 ... Exhaust pipe 43 ... Combustion chamber body 43a ... Case body 4 ... Valve device 44a ... Valve element 44b ... Drive motor 44c ... Opening / closing mechanism unit 45 ... Blowing fan 46 ... ECU 70 ... Intake throttle valve 84 ... Exhaust gas cooler 88 ... EGR device 90 ... EGR passage 92 ... EGR valve 95 ... Branch pipe (introduction 97) Three-way valve (valve device) C1 ... Connection point between the air supply passage 33 and the main pipe 29 (intake passage) or the upstream side connecting pipe 25 (intake passage) C2 ... Combustion gas discharge passage 35 and main pipe 29 ( Intake passage) or a connection point W1 with the upstream side connecting pipe 25 (intake passage) ... Water pipe W2 ... 〃 W3 ... 〃

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI F02N 17/06 F02M 31/06 A (58) Fields investigated (Int.Cl. ⁷ , DB name) F01N 3/08-3 / 36 F02M 25/07 F02M 31/06 F02M 35/10 F02N 17/06

Claims (11)

(57) [Claims] 1. An internal combustion engine having a combustion heater in an intake passage of the internal combustion engine for promoting warm-up and improving startability of the internal combustion engine, wherein the exhaust passage of the internal combustion engine is provided to purify exhaust gas of the internal combustion engine. And a catalytic converter, which is downstream of the combustion heater installation location in the intake passage, and upstream of the exhaust gas passage in the exhaust passage, the bypass being connected to the cylinder of the internal combustion engine. , EG that recirculates the exhaust gas of the internal combustion engine from the exhaust passage to the intake passage as its original function
R passage, and when the internal combustion engine is in a predetermined stop state and it is necessary to operate the combustion heater, the combustion gas emitted by the combustion heater is discharged from the intake passage via the EGR passage. An internal combustion engine having a combustion heater, characterized in that it is sent to the exhaust passage. 2. The EGR passage is provided with an EGR valve for controlling a flow of a circulating gas passing through the EGR passage.
2. The internal combustion engine with a combustion heater according to claim 1, wherein the internal combustion engine is opened when it is necessary to operate the combustion heater in the predetermined stop state. 3. The combustion heater includes an air supply passage for supplying combustion air to a combustion chamber, and a combustion gas discharge passage for discharging combustion gas generated in the combustion chamber from the combustion chamber. The combustion heater is connected to the intake passage via a supply passage and the combustion gas discharge passage, and a connection point between the intake passage and the air supply passage in the intake passage and the intake passage and the combustion gas discharge passage. An intake throttle valve that restricts the intake passage is provided between a connection point with the intake throttle valve, and the intake throttle valve controls the intake air when the internal combustion engine is in the predetermined stop state and it is necessary to operate the combustion heater. An internal combustion engine having a combustion heater according to claim 2, wherein the passage is narrowed. 4. An internal combustion engine having a combustion heater according to claim 3, wherein a supercharger is not installed downstream of a connection point of the intake passage and the combustion gas discharge passage in the intake passage. . 5. An internal combustion engine having a combustion heater according to claim 3, wherein an intercooler is not installed downstream from a connection point between the intake passage and the combustion gas discharge passage in the intake passage. 6. A supercharger and / or an intercooler is installed downstream of a connection point between the intake passage and the combustion gas discharge passage in the intake passage, and the internal combustion engine is in the predetermined stop state. When it is necessary to operate the combustion heater, the combustion gas of the combustion heater has an introduction path for guiding the combustion gas in the intake passage downstream of the supercharger installation location and / or the intercooler installation location. An internal combustion engine having the combustion heater according to claim 1 or 2. 7. The combustion heater includes an air supply passage for supplying combustion air to a combustion chamber, and a combustion gas discharge passage for discharging combustion gas generated in the combustion chamber from the combustion chamber. An intake throttle valve that connects the combustion heater to the intake passage via a supply passage and the combustion gas discharge passage, and throttles the intake passage when the internal combustion engine is in the predetermined stop state is included in the intake passage. The internal combustion engine having the combustion heater according to claim 6, wherein the internal combustion engine is provided upstream of a connection point between the intake passage and the introduction passage. 8. The introduction passage branches from the combustion gas discharge passage, and opens at the branch point when the combustion heater needs to be operated, whereby the combustion gas is introduced into the intake passage. An internal combustion engine having a combustion heater according to claim 6 or 7, further comprising: a valve device that guides the downstream of a supercharger installation location. 9. The valve device closes the introduction passage and opens the combustion gas discharge passage after the internal combustion engine is started, whereby the combustion gas is discharged from the intake passage through the combustion gas discharge passage. The internal combustion engine having a combustion heater according to claim 8, wherein the internal combustion engine is introduced upstream of the supercharger installation location. 10. The E after the internal combustion engine is started.
The internal combustion engine having a combustion heater according to claim 3, wherein a GR valve is operated to close the EGR passage and the intake throttle valve is controlled to increase a passage area of the intake passage. 11. A valve device for closing the air supply passage of the combustion heater is provided in the air supply passage, and the valve device throttles the front intake passage by the intake throttle valve in order to positively stop the drive of the internal combustion engine. The internal combustion engine having the combustion heater according to claim 10, which operates in some cases.