JP2001323844A - Internal combustion engine having a combustion heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine having a combustion type heater capable of making the combustion type heater small, and sufficiently heating a cabin even if the small combustion type heater is used when the internal combustion engine is not operated. SOLUTION: This internal combustion engine has the combustion type heater 17 for heating engine cooling liquid of the engine 1; an EGR passage 19 connecting in a bypass state an intake air passage 9 and an exhaust passage 14 to a cylinder and re-circulating engine exhaust gas from the exhaust passage 14 to the intake air passage 9; an EGR cooler 22 installed in the EGR passage 19 and lowering the temperature of exhaust gas to be re-circulated; and a heater exhaust gas introduction means 47 for introducing the heater exhaust gas into the EGR cooler 22 when the engine 1 is in the specified stop state and the operation of the combustion type heater 17 is required.

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 an exhaust gas recirculation system E.
The present invention relates to an internal combustion engine having a combustion heater provided with GR (Exhaust Gas Recirculation).

[0002]

2. Description of the Related Art An internal combustion engine rotates by utilizing heat energy obtained by burning engine fuel. For this reason, the temperature in the combustion chamber reaches several thousand degrees, and a considerable amount of this heat is absorbed by the cylinder, the cylinder head, the piston, and the like. If the temperature of these parts rises excessively and the internal combustion engine overheats, the lubricating ability decreases and shortens the life of the internal combustion engine,
It will burn the pistons, valves, bearings, etc.

[0003] Therefore, for example, a water-cooled cooling device is employed as a cooling system in the internal combustion engine. As is well known, a water-cooled cooling device is provided with a water jacket on a cylinder block and a cylinder head, a radiator on the front of an internal combustion engine, and the water jacket and the radiator are connected by a pipe through which engine coolant (engine cooling water) passes. The engine coolant is forcibly circulated by a water pump through this line, and the engine coolant heated in the water jacket is sent to the radiator when the engine is operating, where it is cooled by outside air. This prevents overheating and keeps the engine temperature at a proper level.

By the way, from the viewpoint of effective use of heat energy, it is irrational to remove heat by cooling, and the removed heat causes a complete cooling loss and lowers engine output and thermal efficiency. .

[0005] Therefore, heat loss is minimized by providing the engine coolant, which has been heated using the heat energy of the internal combustion engine, to the use of vehicle interior heating (hereinafter referred to as "indoor heating") by using a heat exchanger. I try to be less. However, since a lean-burn internal combustion engine such as a diesel engine has a small amount of heat generation from the beginning, it may not be possible to sufficiently use heat for indoor heating or the like with only the heat energy generated by the engine.

Therefore, in a lean-burn engine,
Separately, a combustion-type heater is installed, and the engine coolant is heated by using the high-temperature exhaust gas (hereinafter referred to as “heater exhaust gas”) of the combustion-type heater in addition to the heat energy generated by the heat generated by the engine itself.
As a result, the performance of the indoor heating is improved, the startability of the internal combustion engine is improved, the warm-up is promoted, the indoor heating is improved, and the like (for example, see Japanese Patent Application Laid-Open No. 60-79149).

The combustion type heater has a combustion chamber for burning fuel, and an engine coolant passage for circulating the engine coolant around the combustion chamber during combustion. Then, while the engine coolant flows through the engine coolant passage, the engine coolant absorbs the heater combustion heat and rises in temperature. That is, heat exchange is performed between the engine coolant and the heater exhaust gas in the engine coolant passage. As a result, the engine coolant, which has become high in temperature, is sent to a place where the temperature needs to be raised, such as a heater core or a water jacket for room heating, thereby improving the startability, promoting warm-up, and improving the performance of room heating as described above. Provided for improvement.

[0008]

However, even in a small vehicle, it is inevitable to reduce the size of the components of the vehicle in order to secure a sufficient indoor space. Absent.

However, when the size of a combustion type heater is reduced, its performance generally decreases. In particular, when room heating is used while the internal combustion engine is stopped in cold weather, room heating must be performed only with the small combustion type heater. Therefore, there is a problem that it is difficult to sufficiently heat the room.

For this reason, there has been a demand for a technique capable of sufficiently heating a room even when only a small combustion type heater is operated while the engine is stopped. On the other hand, an exhaust gas recirculation device (hereinafter referred to as “EGR” unless otherwise specified) is known as a device having a function of reducing nitrogen oxides. The EGR is a device for recirculating exhaust gas from the engine exhaust system to the intake system, and includes a bypass passage (hereinafter, referred to as an “EGR passage”) that connects the exhaust pipe and the intake manifold by bypassing the engine body.
A control valve (hereinafter, referred to as "EGR valve") for controlling the amount of exhaust gas (hereinafter, referred to as "EGR gas") flowing from the exhaust system side to the intake system side in the GR passage, and the temperature of the EGR gas passing through the EGR passage. And an EGR cooler.

The EGR cooler is a heat exchanger for exchanging heat between the EGR gas and the engine coolant. Inside the EGR cooler, an engine coolant passage through which the engine coolant passes and an EGR passage through the engine coolant passage. EG that passes EGR gas while gas is in direct contact
An R gas passage tube is provided. When the engine coolant flows through the engine coolant channel, the EGR gas comes into contact with the engine coolant channel to absorb the temperature of the EGR gas and to reduce the temperature of the EGR gas.
Reduce gas temperature.

As described above, since the EGR cooler is for reducing the temperature of the EGR gas, it is desirable that the temperature of the engine coolant flowing therethrough is as low as possible.
Therefore, the engine coolant supplied to the EGR cooler usually uses an engine coolant flowing through the cylinder block, which has a lower temperature than the engine coolant flowing through the water jacket of the cylinder head.

Further, as described above, there is a case where only the combustion type heater is operated to heat the room while the engine is stopped. In this case, since the internal combustion engine is stopped, the engine is operated when the engine is operated to supply the engine coolant. The circulating water pump (hereinafter referred to as "water pump for engine operation") is also stopped. Therefore, when the combustion type heater is operated while the engine is stopped to heat the room, a dedicated water pump that can circulate the engine coolant even when the engine is stopped is required. Since the water pump must be operated by using the electric power of a battery attached to the vehicle, the water pump is referred to as “electric water pump for parking heater: electric water pump”.

However, in the prior art, when the electric water pump is operated while the engine is stopped, the engine coolant flows into the cylinder block of the engine body and the water jacket of the cylinder head. Met. In this connection, when the combustion heater is operated while the engine is stopped to heat the room, the engine coolant flows through the entire water jacket, so that the engine coolant is heated by the combustion heater. Increased, the rate of temperature rise of the engine coolant was poor, and the temperature of the engine coolant was hard to rise. As a result, it has been considered that even when the engine coolant is supplied to the heater core, it is difficult for hot air to be generated from the vehicle interior heater.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to reduce the size of a combustion type heater, and to provide sufficient indoor heating even when the small size combustion type heater is used when the internal combustion engine is not operating. It is an object of the present invention to provide an internal combustion engine having a combustion-type heater capable of performing the above-described operation.

[0016]

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

(1) A combustion type heater for raising the temperature of engine-related elements of an internal combustion engine, and an intake passage and an exhaust passage are connected to the cylinder in a bypass manner, and exhaust gas is recirculated from the exhaust passage to the intake passage. A recirculation passage, a recirculation gas cooling device installed in the recirculation passage for lowering the temperature of the recirculated exhaust gas, and the combustion heater required to be operated when the internal combustion engine is in a predetermined stop state. sometimes,
Heater exhaust gas introducing means for introducing heater exhaust gas into the recirculating gas cooling device.

Here, the "combustion heater" includes a combustion chamber for burning fuel, and an engine coolant passage for internally circulating the engine coolant such that the engine coolant can absorb the combustion heat of the heater.

The "engine-related elements" include an engine coolant, a water jacket using the engine coolant as a heat medium, a heater core for room heating, and the like. "When it is necessary to operate the combustion type heater" means "when the temperature is about -10C to 15C or cold, when it is extremely cold where the temperature is -10C or less, or when there is a demand for cabin heating. This is when the engine coolant is in a low temperature state of, for example, 40 ° C. or less.

It is preferable that a computer for controlling the entire internal combustion engine, that is, an ECU (Engine Control Unit: hereinafter referred to as “ECU”) is suitable for judging that such requirements are satisfied. Thus, operation control of the internal combustion engine and combustion state control of the combustion type heater are performed.

"The internal combustion engine is in a predetermined stop state" means a stop state before the internal combustion engine starts operating. For example, although the internal combustion engine is not in a cranking state yet, a driver or a passenger A person operates an electric system switch so that the combustion type heater is in an operable state.

The "recirculation gas cooling device" has a gas passage through which gas passes, and a gas passage through which the heat of the gas can be absorbed by the engine coolant. And an engine coolant passage for circulating the engine coolant in the apparatus so that heat can be exchanged between the two.
An EGR cooler is suitable as the recirculating gas cooling device.

In the present mode (1), a recirculation passage is provided for recirculating exhaust gas from the internal combustion engine from the exhaust passage to the intake passage during operation of the engine. Then, when the internal combustion engine is in a predetermined stop state and it is necessary to operate the combustion type heater, the heater exhaust gas is introduced into the recirculating gas cooling device via the heater exhaust gas introducing means.

The heater exhaust gas is a gas whose temperature has been once lowered by absorbing heat by heat exchange with the engine coolant circulating in the engine coolant passage of the combustion type heater. Therefore,
If the heater exhaust gas flows into the recirculating gas cooling device, the heater exhaust gas absorbs heat in the engine coolant in the engine cooling liquid passage of the recirculating gas cooling device when passing through the gas passage of the recirculating gas cooling device. Therefore, not only heat exchange between the heater exhaust gas of the combustion type heater and the engine coolant, but also heat exchange between the heater exhaust gas and the engine coolant by the recirculating gas cooling device is realized. Further, in an internal combustion engine, as is well known, heat loss is reduced as much as possible by supplying an engine coolant to a heat medium or the like of an indoor heating device.

Therefore, according to the present invention, since the heater exhaust gas once heat-exchanged by the combustion type heater passes through the recirculating gas cooling device and is exchanged again by the engine coolant, the heat exchange only by the combustion type heater can be performed. The thermal efficiency can be increased as compared with the case of performing. As a result, the temperature rise rate of the engine coolant increases, and when the engine coolant passes through the heater core, which is the heat exchanger of the indoor heating device, the temperature of the heater core increases. Therefore, the temperature of the air contacting the heater core increases, the temperature of the hot air emitted from the indoor heating device provided in the vehicle interior increases, and the performance of the indoor heating device improves.

The internal combustion engine having the combustion type heater according to the present invention comprises:
Not only the heat exchange by the combustion type heater, but also the heat exchange of the heater exhaust gas by the recirculating gas cooling device installed in the EGR passage, so that the heat exchange is much more efficient than the heat exchange of the heater exhaust gas by the combustion type heater alone. Can be exchanged.

[0027] For this reason, assuming that the same amount of heat is exchanged between the internal combustion engine employing the heat exchange according to the present invention and the internal combustion engine exchanging heat with the combustion heater alone, the two are compared. In the internal combustion engine according to the above, the heat exchange is also performed by the recirculating gas cooling device, and accordingly, the amount of heat exchange carried by the combustion heater can be reduced accordingly. Therefore, the combustion type heater according to the present invention can be downsized.

The present invention is applied when the internal combustion engine is in a stopped state. Therefore, the EGR does not perform its original function at that time, and does not recirculate the exhaust gas from the exhaust passage side to the intake passage side via the EGR passage. Therefore, the heater exhaust gas can flow to the recirculating gas cooling device without obstructing the flow of the heater exhaust gas by the exhaust gas of the internal combustion engine that recirculates in the EGR passage.

(2) In the case of the above (1), the combustion type heater includes an air supply path for supplying air to the combustion chamber, and a combustion type heater using air supplied from the air supply path to the combustion chamber. A heater exhaust gas discharge path for discharging heater exhaust gas generated when the combustion fuel is burned from the combustion chamber, wherein the heater exhaust gas introducing means communicates with the heater exhaust gas discharge path and the recirculation passage. A switching valve that is installed at a junction where the communication path is connected to the heater exhaust gas discharge path and switches the flow direction of the heater exhaust gas discharged from the combustion type heater from the heater exhaust gas discharge path to the communication path. Preferably, it is provided.

(3) In the case of the above (2),
It is preferable that a portion where the communication passage joins to the recirculation passage is closer to the intake passage than a place where the recirculation gas cooling device is installed in the recirculation passage.

Instead, the location where the communication passage is joined to the EGR passage is connected to the EG of the recirculating gas cooling device.
This is because heat exchange using the recirculating gas cooling device becomes extremely difficult if the location is closer to the exhaust passage than to the installation location in the R passage.

(4) In the case of the above (3), an EGR valve for controlling the amount of the recirculated exhaust gas is provided at a portion of the recirculation passage closer to the intake passage than a portion where the communication passage is joined. It is preferable that the EGR valve be closed when the internal combustion engine is installed and the predetermined heater is stopped and the combustion type heater needs to be operated.

By doing so, E is controlled via the communication passage.
The flow of the heater exhaust gas introduced into the GR passage to the intake passage side in the EGR passage is blocked by the EGR valve, and all of the heater exhaust gas introduced into the EGR passage goes to the recirculating gas cooling device. For this reason, heat exchange can be performed without leaking the heater exhaust gas.

(5) In the case of the above (4), it is preferable that the air inlet end of the air supply passage and the heater exhaust gas outlet end of the heater exhaust gas discharge passage are opened to the atmosphere. In this case, since the intake and exhaust of the combustion heater are performed to the atmosphere, it is necessary to perform engine control in consideration of the influence of the intake and exhaust of the combustion heater on the operation even when the internal combustion engine operates. Absent. For this reason, the program of the operation control execution routine of the internal combustion engine and the combustion type heater can be simplified.

In this case, in order to prevent foreign matter, dust and other foreign matter in the intake air from entering the combustion type heater, it is preferable to install filters for removing the foreign matter in the air supply passage and the heater exhaust gas discharge passage. .

(6) In the case of the above (4), the air inlet end of the air supply passage and the heater exhaust gas outlet end of the heater exhaust gas discharge passage are connected to the intake passage to remove dust, dirt and other foreign matter in the intake air. It can also be connected downstream from the installation location of the air cleaner to be removed.

In this case, since the air that has passed through the air cleaner does not include dust, dust, and other foreign substances, the filter described in (4) can be eliminated. (7) In any one of the above (1) to (6), there is provided a main pump which operates when the engine is operating, and the main cooling liquid path which circulates the engine cooling liquid between the engine cooling system and the radiator by operating the pump. A main coolant passage separate from the main coolant passage, and a sub coolant passage including the combustion heater and the recirculating gas cooling device, wherein the internal combustion engine is in the predetermined stop state. When it is necessary to operate the combustion heater, the engine coolant may be circulated in the sub-coolant passage but not in the main coolant passage. Here, the “in-engine cooling system” refers to a cylinder block and a cylinder head having a water jacket.

In this case, when the internal combustion engine is in the predetermined stop state and it is necessary to operate the combustion type heater, the engine coolant circulates in the sub coolant channel but does not circulate in the main coolant channel. Therefore, the engine coolant flows only in the sub-coolant passage and not in the main coolant passage. Therefore, since the engine coolant does not flow to the main pump, the internal cooling system, and the radiator provided in the main coolant path, the heat loss can be reduced accordingly.

In this case, the amount of circulating engine coolant is limited to that of the sub-coolant passage, and the amount is small. That is, since the flow rate of the engine coolant flowing through the combustion heater per unit time is small, if the combustion heat of the heater is constant, the rate of temperature rise of the engine coolant in the sub-coolant passage due to the heat of the combustion heater increases. .

Therefore, if the engine coolant which has been heated in accordance with the reduction of the heat loss is used as a heat source of a heating device for indoor heating of a vehicle equipped with an internal combustion engine, the performance of the heating device can be improved.

From this point of view, the present invention can be applied to an internal combustion engine having a combustion heater having the following feature (8). (8) That is, in the case of the above item (7), the sub-coolant passage includes a heating device for heating the interior of the vehicle equipped with the internal combustion engine, and the heating device, the combustion type heater, and the recirculation gas cooling device include: A heat exchanger for the heating device, wherein the engine coolant is provided as a heat medium when the internal combustion engine is in the predetermined stop state and the combustion heater needs to be operated. A heat exchanger that raises the temperature of the air by directly or indirectly contacting the engine coolant with the air in the vehicle compartment, and the heat exchanger of the combustion heater and the recirculating gas cooling device includes:
A heat exchanger for exchanging heat between the engine coolant and the heater exhaust gas provided to the combustion heater and the recirculating gas cooling device.

In this case, as the heat exchanger of the heating device,
Known heater cores are preferred. When a heater core is applied to the heat exchanger, the temperature of the heater core increases when the heated engine coolant passes through the heater core. Therefore, the temperature of the air contacting the heater core increases, the temperature of the hot air emitted from the indoor heating device provided in the vehicle interior increases, and the performance of the indoor heating device improves.

(9) In the case of the above (7) or (8), it is preferable that the sub-coolant passage has a sub-pump which circulates the engine coolant in the sub-coolant passage even while the engine is stopped.

When heating the room by operating only the combustion type heater while the engine is stopped, the internal combustion engine is stopped.
The engine operating water pump that operates during engine operation and circulates engine coolant is stopped. Therefore, when heating the room by operating the combustion type heater while the engine is stopped,
Even if the engine is stopped, a dedicated water pump that can circulate the engine coolant is required.
As the pump, an electric water pump that operates using electric power of a battery attached to a vehicle is preferable.

(10) In the case of the above (9), the sub-coolant passage is formed of a common portion and a non-common portion between the sub-coolant passage and the main coolant passage, and the common portion is provided with the recirculated gas cooling. The device may also include the combustion heater, the heating device, and the sub-pump in the non-shared portion.

Here, the "common portion" is a portion for forming a sub-cooling liquid passage and a portion for forming a main cooling liquid passage. The provision of the recirculation gas cooling device in this common portion is that the recirculation gas cooling device originally functions when the engine is operating, and recirculates exhaust gas of the internal combustion engine from the exhaust passage to the intake passage to reduce nitrogen oxides. It is a component of the exhaust gas recirculation device (EGR) to be used. In the present invention, the recirculation gas cooling device is used while the engine is stopped when the exhaust gas recirculation device is not functioning. A recirculation gas cooling device is provided.

The "non-shared portion" means a portion of the sub-coolant passage forming portion except for the shared portion. By providing the EGR cooler in the common part, the thermal efficiency can be increased as described above while the engine is stopped by cooperation with the combustion type heater in the non-common part, but as a component of the exhaust gas recirculation device during the operation of the engine. The temperature of the exhaust gas flowing through the recirculation passage can be reduced.

(11) In the case of the above (10), the engine coolant is supplied from the combustion heater to the heating device to the recirculated gas cooling device starting from the combustion heater by the pump pressure of the sub-pump. It is preferable to circulate through the sub-coolant passage in this order.

(12) In the case of the preceding paragraph (11), the sub-coolant passage is connected from the sub-coolant passage to the main pump of the main coolant passage by connecting the sub-coolant passage and the main coolant passage. It is preferable that an inflow pipe into which the engine coolant flows is provided, and the sub-pump is disposed downstream of a connection point between the inflow pipe and the sub-coolant liquid path in the sub-coolant liquid path.

By providing the inflow pipe, during operation of the engine, the engine coolant is introduced from the sub-coolant passage toward the main pump in the main coolant passage. It is possible to improve the engine warm-up by the combustion heat of the combustion heater in addition to the heating of the vehicle interior during operation.

Also, since the sub-pump is arranged downstream of the connection point between the inflow pipe and the sub-coolant path in the sub-coolant path, the sub-pump is operated by the pump pressure of the sub-pump while the engine is stopped. The engine coolant in the coolant passage does not flow through the inflow pipe to the main coolant passage but circulates in the sub-coolant passage.

(13) The sub-coolant passage is connected to the main coolant passage, and the engine coolant in the sub-coolant passage flows from the sub-coolant passage toward the main pump of the main coolant passage. A switching valve is provided at a connection point between the inflow pipe and the sub-coolant passage, and the sub-pump is disposed upstream of the switching valve installation point in the sub-coolant passage, when the engine is operating. Switches the switching valve to flow the engine coolant flowing through the sub-coolant passage to the inflow pipe, and to apply the engine coolant to the sub-coolant passage and the main coolant by both pump pressures of the sub-pump and the main pump. It is preferred that the engine coolant is circulated only in the sub-coolant passage by switching the switching valve when the engine is stopped and by the pump pressure of the sub-pump when the engine is stopped. By the switching valve, the circulation place of the engine coolant during the operation of the engine and during the stop of the engine can be clearly distinguished.

[0053]

Embodiments of the present invention will be described below with reference to the accompanying drawings. <First Embodiment> A first embodiment according to the present invention will be described with reference to FIGS. 1 to 5 and FIG.

The engine 1 as an internal combustion engine is of a water-cooled type, and as shown in FIG.
Engine body 3 having a jacket, and engine body 3
And an exhaust device 7 for feeding exhaust air required for engine combustion into a plurality of unillustrated cylinders, and an exhaust device 7 for exhausting exhaust gas emitted after burning fuel with the air.

The intake device 5 has an intake passage 9 which starts with an air cleaner 7 for removing dirt, dust and other foreign matters in the intake air and terminates at an intake port (not shown) of the engine body 3. An intake system structure such as a throttle valve 11 serving as an intake throttle valve and an intake manifold 13 serving as a suction branch pipe is provided therebetween.

The exhaust device 7 has an exhaust passage 14 which starts at an exhaust port (not shown) of the engine body 3 and ends at a muffler (not shown). An exhaust manifold 15 serving as an exhaust manifold and an exhaust system structure such as a catalytic converter (not shown) enclosing an exhaust gas purifying catalyst are provided between the exhaust manifolds.

The engine 1 is provided with an EGR 18 as an exhaust gas recirculation device for reducing the NOx generated in the cylinder by returning a part of the exhaust gas to the intake system.
The EGR 18 connects the exhaust passage 14 and the intake passage 9 to a cylinder (not shown) of the engine body 3 in a bypass shape, and originally recirculates the exhaust gas of the engine 1 from the exhaust passage 14 to the intake passage 9. EGR passage 1
9 Exhaust gas that recirculates between the exhaust system and the intake system through the EGR passage 19, so-called EGR
An EGR valve 21 for controlling the amount of gas is provided.

The EGR valve 21 is electrically connected to an ECU (not shown) and is basically opened when the engine 1 is sufficiently warmed up. However, the embodiment according to the present invention is intended for a stopped state (during engine stop) before the engine 1 starts operating. For example, although the engine 1 is not in a cranking state yet, a driver or a passenger may not be in a cranking state. Activate the switch of the electrical system and therefore the combustion type heater 1
7 is closed when it is in an operable state, that is, in a predetermined stop state.

The EGR valve 21 is connected to a pressure control valve (not shown) for negatively controlling the EGR valve 21 such as a duty VSV. In this pressure control valve, a drive pulse signal having a duty ratio corresponding to the ratio between the fully open time and the fully closed time of the EGR valve 21, in other words, the duty ratio corresponding to the open ratio of the EGR valve 21,
When input from the CPU which is the central processing controller of U,
The EGR valve 21 is opened and closed according to the pulse signal.

The EGR passage 19 has an EGR cooler 22 as a recirculating gas cooling device for lowering the temperature of the recirculated exhaust gas during operation of the engine 1 at a position near the exhaust passage 14 of the EGR passage 19.

The device denoted by reference numeral 17 includes an engine cooling liquid as an engine-related element of the engine 1, a water jacket in the engine body 3 using the engine cooling liquid as a heat medium, and a heater core 24 for room heating (engine). (Refer to FIG. 2 showing a flow chart of the cooling liquid.) This is a combustion-type heater that raises the temperature of other necessary portions.

The combustion heater 17 is provided with an air supply passage 33 for supplying the combustion air from the atmosphere, and when the combustion fuel of the combustion heater 17 is burned by the air supplied from the air supply passage 33. It has a heater exhaust gas discharge passage 35 for discharging the generated heater exhaust gas from a combustion chamber (described later) of the combustion heater 17 into the atmosphere.

Further, when the engine 1 is in the predetermined stop state and it is necessary to operate the combustion type heater 17, the EGR passage 19 is directed to a position closer to the intake passage 9 than the place where the EGR cooler 22 is installed. In order to introduce the heater exhaust gas, the engine 1 includes a heater exhaust gas discharge passage 3.
A communication passage 46 that connects the EGR passage 5 and the EGR passage 19 is arranged. The EGR passage 19 is located at a position closer to the intake passage 9 than a position where the communication passage 46 is joined.
A valve 21 is provided.

The communication passage 46 of the heater exhaust gas discharge passage 35
Of the combustion type heater 1
7, a valve device 44 is provided at this junction.
Although not shown, the valve device 44 includes an appropriate switching valve that switches the direction of the flow of the heater exhaust gas discharged from the combustion heater 17 from the heater exhaust gas discharge passage 35 to the communication passage 46, And an opening / closing mechanism including a drive motor for driving the opening / closing.

Since the valve device 44 includes a switching valve, it can be said that a switching valve is provided at the junction. The operation of the drive motor is controlled by a CPU (not shown) of the ECU. The switching valve switches the direction of the flow of the heater exhaust gas toward the heater exhaust gas discharge passage 35 or the communication passage 46 according to the operation control.

Therefore, the communication passage 46 and the valve device 44 are controlled by the combustion type heater 17 when the engine 1 is in a predetermined stop state.
A heater exhaust gas introducing means for introducing heater exhaust gas into the EGR cooler 22 when it is necessary to operate the heater.
Indicated by 7.

The switching valve is switched to the side of the communication passage 46 when the engine 1 is in a predetermined stop state and the combustion type heater 17 needs to be operated, but is switched to the side of the communication passage 46 after the engine 1 is started. You can also.

The phrase "when it is necessary to operate the combustion heater 17" means that the temperature is in a cold state of about -10.degree. C. to about 15.degree. When the engine coolant is in a low temperature state of, for example, 40 ° C. or less.

The condition for operating the combustion type heater 17 when the engine 1 is in a predetermined stop state is referred to as "the preheating condition of the combustion type heater 17 is satisfied while the engine is stopped" for convenience. The operation of the combustion heater 17 when the preheating condition of the combustion heater 17 is satisfied is referred to as the execution of preheating of the combustion heater 17. However, the fact that the preheating condition of the combustion type heater 17 is satisfied does not mean that the combustion type heater 17 immediately starts combustion, but only after the operation start control of the combustion type heater 17 is executed. 17 operates.

Next, the structure of the combustion type heater 17 is schematically shown with reference to FIG. The combustion heater 17 is for raising the temperature of the engine coolant, and is therefore connected to the water jacket containing the engine coolant. Therefore, the combustion heater 17 has an engine coolant passage 17a through which the engine coolant passes. The engine coolant passage 17a is heated by the exhaust gas of the heater flowing through the combustion chamber 17d as a heat source.

The combustion chamber 17d is formed by disposing a combustion cylinder 17b therein and covering the combustion cylinder 17b with a cup-shaped partition wall 17c. Further, the combustion cylinder 17 is formed by the partition wall 17c.
b, the combustion chamber 17d is defined in the case body 43a of the combustion chamber body 43, and the engine coolant passage 1 is provided between the inner surface of the case body 43a and the outer surface of the partition wall 17c.
7a is formed.

The combustion chamber 17d also functions as an air passage in the heater. Therefore, the air supply port 17d is provided in the combustion chamber 17d.
₁ and the exhaust outlet 17d ₂ are formed, these air supply ports 17d ₁ and the exhaust outlet 17d ₂ are combustion heater 1
7 are connected to the air supply path 33 and the heater exhaust gas discharge path 35, respectively.

The air (see the solid arrow in FIG. 3) introduced from the atmosphere into the combustion type heater 17 via the air supply path 33 passes through the combustion chamber 17d and the heater exhaust gas discharge path 35, and becomes heater exhaust gas. The air is discharged from the outlet end 35a of the heater exhaust gas discharge passage 35 to the atmosphere.

The inlet end of the air supply passage 33 opened to the atmosphere as well as the outlet end of the heater exhaust gas discharge passage 35 is denoted by reference numeral 33a. Since the heater exhaust gas has a high heat, the heater exhaust gas flows through the engine coolant passage 17a before the heater exhaust gas is discharged from the combustion chamber main body 43 through the path indicated by the solid line arrow in FIG. (See dashed arrow in FIG. 3). Therefore, the combustion chamber 17d and the engine coolant passage 17a constitute a heat exchanger for exchanging heat between the heater exhaust gas and the engine coolant passing therethrough. Therefore, it can be said that the combustion heater 17 has a heat exchanger.

The combustion cylinder 17b is supplied with combustion fuel through a fuel supply pipe 17e as a fuel supply passage. When the combustion fuel is supplied to the combustion chamber 17d,
The fuel is vaporized in the combustion chamber 17d. Then, the vaporized fuel is ignited by an ignition device (not shown), and the vaporized fuel burns.

On the other hand, the engine coolant passage 17a has an engine coolant inlet 17a1 and an engine coolant outlet 17a2 (see FIGS. 2 and 3), and the engine coolant inlet 17a1.
Is connected to an engine coolant outlet of a water jacket (not shown) of the block 32 and the head 34 of the engine body 3 via an engine coolant line W1. The engine coolant line W1 is connected to the radiator 26, the thermostat 2
8 and the EGR cooler 22.

The engine coolant discharge port 17a2 is connected to a heater core 24, which is a heat exchanger of a vehicle interior heating device of an engine-equipped vehicle, via an engine coolant pipe W2. A water pump 30 for the combustion heater 17 is provided in the engine coolant line W2.
Is operated mainly by the electric power of the battery while the engine 1 is stopped, and the water pump 30 circulates the engine coolant. Therefore, the water pump 30 is referred to as an electric water pump for a parking heater: an electric water pump.
It may be called a pump. This electric water pump 30
Can also be activated during engine operation. The heater core 24 is connected to an engine coolant inlet (not shown) of the water jacket of the engine body 3 via an engine coolant line W3. Engine coolant line W
An engine operating water pump 36 for circulating the engine coolant when the engine 1 is operating is provided in the engine 3.

Further, the engine coolant line W 3 is connected to the thermostat 28 and the radiator 26 via a water pump 36. However, since the water pump 36 operates when the engine 1 is operating,
When the engine 1 is stopped, the engine coolant is circulated by the water pump 30 for the combustion heater 17 which is operated by battery power as described above.

Accordingly, the engine coolant of the water jacket is supplied to the combustion type heater 1 through the engine coolant line W1.
7 and is heated there.
To the heater core 24 via the engine coolant line W2, the engine coolant as the heat medium of the heater core 24 directly or indirectly contacts the air in the vehicle cabin (see the thick arrow in FIG. 10). Heats the vehicle interior air 25 by the heat exchange performed between the air and the air, so that the warm air 25 '
Put out.

The heater core 24 is formed by attaching a plurality of fins 62 to a water pipe 60 through which the engine coolant flows. The heater core 24 is disposed in the middle of the engine coolant channels W2 and W3, and is provided with the engine coolant inlet / outlet 60a and the engine coolant channel 60. 60b.

The entrances 60a and 60a
b is connected to the engine coolant line W3 and the engine coolant line W2, respectively, which connect the combustion heater 17 and the engine operation water pump 36. Since the heater core is basically similar in structure to a known radiator, a detailed description is omitted, and only the disclosure of FIG.

Further, since the heater core 24 is a main part of the heating device, in this specification, the heater core 24 is used.
May be rephrased as a heating device. The engine coolant whose temperature has been lowered by the heat exchange returns to the water jacket via the engine coolant line W3. Thus, the engine coolant circulates between the engine body 3, the combustion heater 17, and the heater core 24 via the engine coolant channels W1 to W3.

The combustion chamber main body 43 further includes a blower fan 45 and a CPU 52 which is a central processing control unit dedicated to the combustion type heater 17.
7 is suitably operated, and a flame F is generated in the combustion chamber 17d.

Next, the structure of the EGR cooler 22 will be schematically described with reference to FIG. The EGR cooler 22 is provided in the EGR passage 19 and serves as a part of the EGR passage 19 and has a portion functioning as a heat exchanger similarly to the combustion type heater 17. Exchange heat between the two.

The EGR cooler 22 includes a cooler case 40
The case 40 has a cylindrical shape with both ends opened. A plurality of EGR gas passage forming pipes 41, 4 which form the EGR passage 19 as a whole therein.
1, ..., located at both ends of the cooler case 40
The fixed support plate 4 for fixing both ends of the GR gas passage forming tubes 41, 41,... And supporting and fixing the EGR gas passage forming tubes 41, 41,.
8, 48.

A fixed space is provided inside the cooler case 40 by the fixed support plates 48, 48, in which the plurality of EGR gas passage forming pipes 41, 41,. S is formed.

The cooler case 40 is provided with inlets / outlets 40a and 40b for the engine coolant so that the engine coolant (see broken arrows in FIG. 4) can freely circulate in the space S. In the entrance 40b and the exit 40a,
The engine coolant lines W3 and W1 are connected to each other, and the engine coolant flowing from the inlet 40b flows toward the outlet 40a while freely circulating the engine coolant in the space S, during which the engine coolant flows. And heat exchange between the heater exhaust gas (see the solid arrow in FIG. 4). In this specification, W1 to W3 may be collectively indicated by a reference symbol W as needed.

The fixed support plate 43 is provided with the EGR gas passage forming pipes 41 and 4 because the engine coolant circulates through the space S of the cooler case 40 partitioned by the fixed support plates 48 and 48.
The fixed support plate 48 also has a function as a sealing material so that the engine coolant does not leak from a portion that contacts with the inner surface of the cooler case 40. Further, the engine coolant is supplied to the EGR gas passage forming pipe 4.
In order to facilitate passage between the EGR gas passage forming tubes 41, 41,..., Appropriate gaps 42, 42,.

Since the engine coolant flows through the gaps 42, 42,..., The gaps 42, 42,. To

The flanges 50 provided at both ends of the cooler case 40 are for mounting the EGR cooler 22 as a part of the EGR passage 19. EG
Since heat is exchanged between the R gas passage forming pipes 41, 41, and the engine coolant passages 42, 42,.
It can be said that the cooler 22 has a heat exchanger.

Next, an operation control start execution routine of the combustion type heater 17 will be described with reference to FIG. This routine is for operating the combustion type heater 17 before driving the engine 1, and is described below in S101 to S10.
6 steps.

A flowchart composed of the steps constituting this routine is stored in a read-only memory ROM (not shown) of the ECU. Further, a flowchart according to the second embodiment is also stored in the ROM. The processing in each step of each flowchart is entirely performed by the CPU of the ECU.

Note that the symbol S is used, for example, in step 10
If it is 1, it is abbreviated as S101. The flowchart will be described.

When a start command for the combustion type heater 17 is issued, it is first determined in S101 whether or not the preheating condition of the combustion type heater 17 is satisfied when the engine 1 is stopped.

If an affirmative determination is made in S101, the operation proceeds to S102. Conversely, if a negative determination is made, this routine is terminated, and the operation control of the combustion heater 17 at the time of starting the engine is performed.

Since the present invention relates to controlling the operation of the combustion heater 17 when the engine 1 is stopped, it cannot be applied when the engine 1 is operating.
Therefore, the determination for this is made in S101. At the same time, even though the preheating condition is not satisfied, the combustion type heater 1
Since it is meaningless to activate 7, the determination is made first in this step.

In S102, it is determined whether the EGR valve 21 is closed. If a positive determination is made in S102, S10
3 and if a negative determination is made, the process proceeds to S104 and the EGR valve 2
1 and then returns to S102 and proceeds to S103.

If the EGR valve 21 is not closed, the heater exhaust gas flowing to the EGR passage 19 via the communication passage 46 flows toward the intake passage 9 via the EGR valve 21.
Since the heat exchange by the EGR cooler 22 becomes impossible, the step for preventing this is S102.

In S103, the switching valve (not shown) of the valve device 44 is switched to the communication passage 46. Thereby, the heater exhaust gas discharged from the combustion type heater 17 flows into the intake passage 19 through the communication passage 46. This is for performing heat exchange of the heater exhaust gas by the EGR cooler 22 provided in the EGR passage 19.

At S105, the water for combustion type heater
The pump 30 is started. In S106, the combustion type heater 17
Is performed, and this routine ends.

The configuration described above is the engine 1 as an internal combustion engine having the combustion heater according to the first embodiment. <Operation and Effect of First Embodiment> Next, the operation and effect of the first embodiment will be described.

The EGR 18 of the engine 1 has an EGR passage 19 for recirculating the exhaust gas from the exhaust passage 14 to the intake passage 9 during operation of the engine. When the engine 1 is in the predetermined stop state and the combustion type heater 1
When it is necessary to operate the heater exhaust gas 7, the heater exhaust gas is supplied to a heater exhaust gas introducing means 47 comprising a communication passage 46 and a valve device 44.
Through the EGR cooler 22 provided in the EGR passage 19.

The heater exhaust gas discharged from the combustion type heater 17 is a gas whose temperature has once decreased due to heat absorption by heat exchange with the engine coolant circulating in the engine coolant passage 17a of the combustion type heater 17. Still, for example, 200 ° C
Temperature.

Therefore, the combustion chamber 17d of the combustion heater 17
If the heater exhaust gas discharged from the heater exhaust gas and introduced into the EGR passage 19 via the valve device 44 → the communication passage 46 via the communication passage 46 flows into the EGR cooler 22, the heater exhaust gas is discharged from the EGR cooler 22. Gas passage forming pipe 4
When passing through 1, 41,..., Heat is absorbed by the engine coolant flowing through the engine coolant passage 17a of the EGR cooler 22.

Therefore, not only heat exchange between the exhaust gas of the combustion type heater 17 and the engine coolant but also heat exchange between the heater exhaust gas and the engine coolant by the EGR cooler 22 are realized.

Therefore, in the engine 1, the heater exhaust gas once heat-exchanged by the combustion type heater 17 passes through the EGR cooler 22 and is exchanged again by the engine coolant. The thermal efficiency can be increased as compared with the case where it is performed. As a result, the rate of temperature rise of the engine coolant increases, so that when the engine coolant passes through the heater core 24, the heater core 24
Temperature rises. Therefore, the temperature of the air that comes into contact with the heater core 24 increases, and the temperature of the hot air emitted from the heating device provided in the vehicle interior increases, so that the performance of the indoor heating device can be improved.

As described above, the engine 1 performs not only the heat exchange by the combustion heater 17 but also the heat exchange of the heater exhaust gas by the EGR cooler 22.
The heat exchange can be performed very efficiently as compared with the case where the heat exchange of the heater exhaust gas is performed only by the heat exchange.

For this reason, comparing the engine 1 and the engine that performs heat exchange with the combustion type heater alone on the assumption that the same amount of heat exchange is performed, the engine 1 is also capable of exchanging heat with the EGR cooler 22. As a result, the amount of heat exchange carried by the combustion heater 17 can be reduced accordingly. Therefore, the combustion heater 17 of the engine 1 can be downsized.

The present invention is applied when the engine 1 is in a stopped state. Therefore, the EGR passage 19 does not exhibit the function of recirculating the exhaust gas from the exhaust passage 14 toward the intake passage 9. For this reason, the heater exhaust gas flows to the EGR cooler 22 without being obstructed by the exhaust gas of the engine 1 recirculating in the EGR passage 19.

Further, the communication passage 46 of the EGR passage 19
EGR at a location closer to the intake passage 9 than where the
When the valve 21 is installed and the engine 1 is in the predetermined stop state and the combustion heater 17 needs to be operated, E
When the GR valve 21 is closed, the flow of the heater exhaust gas introduced into the EGR passage 19 through the communication passage 46 is blocked in the EGR passage 19 by the EGR valve 21 and introduced into the EGR passage 19. All of the heater exhaust gas goes to the EGR cooler 22. For this reason, heat exchange can be performed without leaking the heater exhaust gas.

The air inlet end 3 of the air supply path 33
3a and a heater exhaust gas outlet end 35a of the heater exhaust gas discharge passage 35 are open to the atmosphere. Therefore, in this case, the intake and exhaust of the combustion type heater 17 are performed with respect to the atmosphere. Therefore, even if the engine 1 is operated, the intake and exhaust of the combustion type heater 17 are controlled in the operation control of the engine 1 at that time. There is no need to control the engine in consideration of the effect of the engine.
Therefore, the program of the operation control execution routine of the engine 1 and the combustion heater 17 can be simplified.

In this case, filters for removing dust, dirt and other foreign matter in the intake air are installed in the combustion type heater 17 in the air supply path 33 and the heater exhaust gas discharge path 35. Of course, it is preferable. <Second Embodiment> Next, an engine 1A according to a second embodiment of the internal combustion engine having the combustion type heater of the present invention and an engine 1B as a modified example thereof will be described with reference to FIGS.

First, the engine 1A is different from the engine 1 of the first embodiment in that the air supply passage 33 of the combustion heater 17 is different.
The air inlet end 33a and the heater exhaust gas outlet end 35a of the heater exhaust gas discharge passage 35 are connected downstream of the installation location of the air cleaner 7 for removing dirt, dust and other foreign matter in the intake air in the intake passage 9. In particular,
The connection is made at a location located between the air cleaner 7 and the throttle valve 11. Therefore, the same portions as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

Next, the combustion type heater 17 according to the second embodiment
A flow chart for explaining the operation control start execution routine of FIG. This flowchart is composed of eight steps, but the number of steps S201 for asking the open / close state of the throttle valve 11 and the related step S202 are increased as compared with the flowchart of the first embodiment (see FIG. 5). Therefore, only the relevant step will be described, and the steps performing the same processing as the processing in the flowchart of the first embodiment will be denoted by the same step numbers as those of the first embodiment, and description thereof will be omitted. .

After making an affirmative determination in S102, the process proceeds to S102.
Go to 201. In S201, it is determined whether the throttle valve 11 is closed. When a negative determination is made in S201, the process proceeds to S202, and when an affirmative determination is made, the process proceeds to S103.

In S202, the throttle valve 11 is closed, and thereafter, the flow returns to S201. (Modification) FIGS. 8 and 9 show an engine 1B according to a modification of the second embodiment.

The engine 1B according to this modification is different from the engine 1A in that an air inlet end 33a of an air supply passage 33 of the combustion type heater 17 and a heater exhaust gas discharge passage 3 are provided.
5 in that the exhaust gas outlet end 35 a of the heater 5 is connected downstream of the installation location of the air cleaner 7 but downstream of the throttle valve 11 in the intake passage 9.

Therefore, the same portions as those in the case of engine 1A are denoted by the same reference numerals, and description thereof will be omitted. Also, in the flowchart of the engine 1A, the determination of whether or not the throttle valve 11 is closed is performed in S201 in the flowchart of the engine 1A.
Asks if 1 is open. When a negative determination is made in S201, the process proceeds to S202, and when an affirmative determination is made, the process proceeds to S103.

In S202, the throttle valve 11 is opened, and thereafter, the flow returns to S201. <Operation and Effect of Second Embodiment> Next, the operation and effect of the second embodiment will be described.

In the second embodiment including such a modified example of the configuration, as in the first embodiment, even if the combustion type heater 17 is downsized, the heat exchange can be performed so that sufficient indoor heating can be performed. In addition to the above, for example, the following operation and effect can be obtained.
The air inlet end 33a of the air supply passage 33 and the heater exhaust gas outlet end 35a of the heater exhaust gas discharge passage 35
Of these, it is connected downstream from the installation location of the air cleaner 7 that removes dust, dust and other foreign matter in the intake air. Therefore, since the air that has passed through the air cleaner 7 does not include dust, dust, and other foreign matter, the filter described in the first embodiment is connected to the air supply path 33 and the heater exhaust gas discharge path 3.
5 can be unnecessary. <Third Embodiment> Next, with reference to FIGS. 11 and 12, an engine 1C according to a third embodiment of the internal combustion engine having the combustion type heater of the present invention and an engine 1D as a modification thereof will be described.
Will be described.

First, the engine 1C is different from the engine 1 of the first embodiment in that an engine coolant flows through a coolant passage between a cylinder block 32, a cylinder head 34, and a radiator 26, which are internal cooling systems. A main coolant passage which circulates, and a sub-coolant passage which is a separate coolant circulation passage separate from the main coolant passage and includes a combustion heater 17 and an EGR cooler 22 which is the recirculating gas cooling device.
When the engine 1C is in the predetermined stop state and it is necessary to operate the combustion heater 17 as a path, the engine coolant is circulated in the auxiliary coolant path but not circulated in the main coolant path. In a related point.

The details will be described. The main coolant path includes an engine operation water pump 36 that is a main pump that operates when the engine is operating. The pump operates to circulate the engine coolant between the internal cooling system and the radiator. It is a route.

More specifically, when the engine is operating and the radiator 26 is operating, the block 32 → the head 34 starts from the engine operating water pump 36.
And the EGR cooler 22 → radiator 26 → thermostat 28 → water pump 36 for engine operation in the order of the engine cooling fluid pipe W (W1 etc.) connecting these engine parts.
Is a coolant passage that circulates the engine coolant through the coolant passage.

When the engine is operating and the radiator 26
Is not working, the water pump for engine operation 3
6 as a base point, from there a block 32 → the head 34 and the EGR cooler 22 → a water pump 3 for engine operation
6, the engine coolant line W connecting these engine parts.
Is a coolant passage that circulates the engine coolant through the coolant passage.

The sub-coolant passage includes an electric water pump 30 which is a sub-pump which operates when the engine is stopped, and which does not circulate the engine coolant through the main coolant passage by operating the pump. It is.

More specifically, the engine coolant is supplied from the combustion heater 17 to the heater core 24 to the electric water pump 30 to the EGR starting from the combustion heater 17 by the pump pressure of the electric water pump 30. Cooler 22 →
This is a coolant passage which circulates the engine coolant through the engine coolant line W connecting the engine parts in the order of the combustion heater 17.

The block 32 in the sub-coolant passage is
The path through which the engine coolant flows through the EGR cooler 22 and connects the combustion heater 17 is referred to as a common portion,
The other part, that is, the part including the combustion heater 17, the heater core 24, and the electric water pump 30 is referred to as a non-shared part.

Therefore, the sub-coolant passage is formed of a shared portion and a non-shared portion with the main coolant passage. Further, in the engine 1C, the sub-coolant passage is connected to the sub-coolant passage, and the sub-coolant passage is moved from the sub-coolant passage toward the engine operating water pump 36 in the main coolant passage. A part of the engine coolant passage W3 into which the engine coolant flows is referred to as an inflow pipe 80, and is located downstream of a connection point C1 between the inflow pipe 80 and the auxiliary coolant path in the sub-coolant path. The electric water pump 30 is disposed at the second position.

The electric water /
An ON / OFF valve 82 is provided near the downstream of the pump 30. The ON / OFF valve 82 is closed except when the engine 1C is stopped and the combustion heater 17 needs to be operated.

The engine coolant line in which the ON / OFF valve 82 is installed is indicated by reference numeral W4. Engine coolant line W4
Is an engine coolant line connecting the connection point C1 and the EGR cooler 34. (Modification) FIG. 12 shows an engine 1D according to a modification of the third embodiment.

The engine 1d according to this modified example is different from the engine 1C in that an engine coolant line W4 extends from the engine coolant line W4 instead of providing a three-way valve 84 as a switching valve at the connection point C1.
The N / OFF valve 82 is eliminated, and the electric water pump 30 is disposed in the sub-coolant passage at a location where the three-way valve 84 is installed and upstream of the heater core 24.

When the engine is operating, the three-way valve 84 is switched so that the engine coolant flowing through the auxiliary coolant path flows into the inflow pipe 80, and the electric water pump 30 and the engine-operated water pump 36 are operated. The engine coolant flows through both the sub-coolant passage and the main coolant passage by both pump pressures. When the engine is stopped, the three-way valve 84 is switched and the engine coolant is pumped by the pump pressure of the sub-pon electric water pump 30. Is circulated only in the sub-coolant passage. <Operation and Effect of Third Embodiment> Next, the operation and effect of the third embodiment will be described.

In the third embodiment including such a modification of the structure, as in the first and second embodiments, even if the combustion heater 17 is downsized, heat exchange is sufficient to enable sufficient indoor heating. In addition to the effect that can be achieved, for example, the following operation and effect can be obtained.

That is, when the engines 1C and 1D are in the predetermined stopped state and it is necessary to operate the combustion type heater 17, the engine coolant circulates in the sub-coolant passage, but in the main coolant passage. Since it does not circulate, the engine coolant flows only in the sub-coolant path and not in the main coolant path. Therefore, the engine coolant does not flow through the engine operating water pump 36, the block 32, the head 34, and the radiator 26 provided in the main coolant path, so that the heat loss can be reduced accordingly.

In this case, the amount of the circulating engine coolant is limited to that of the sub-coolant passage, and the amount is small. That is, since the flow rate of the engine coolant per unit time flowing through the combustion heater 17 is small, if the heater combustion heat is constant,
The rate of temperature rise of the engine coolant in the sub coolant path due to the heat of the combustion heater 17 increases.

Thus, the performance of the heating device can be improved by using the engine coolant, which has been heated in accordance with the reduction in heat loss, as a heat source of, for example, a heating device for indoor heating of a vehicle.

In addition, the above-mentioned raised engine coolant is supplied to a heater
After passing through the core 24, the temperature of the heater core 242 increases. Therefore, the temperature of the air contacting the heater core 24 increases, the temperature of the hot air emitted from the indoor heating device provided in the vehicle interior increases, and the performance of the indoor heating device improves.

In addition, the EGR cooler 22
When the engine is stopped, the thermal efficiency can be increased in cooperation with the combustion type heater 17 in the non-shared portion, while the temperature of exhaust gas flowing through the EGR passage 19 as a component of the EGR is reduced during operation of the engine. be able to.

Further, by providing the inflow pipe 80, during operation of the engine, the engine coolant is introduced from the sub coolant path to the engine operation water pump 36 in the main coolant path. If the introduction is performed at the time of starting the engine, it is possible to improve the engine warm-up by the combustion heat of the combustion heater 17 in addition to the heating of the vehicle interior during the operation of the engine.

Further, since the electric water pump 30 is disposed downstream of the connection point C1 between the inflow pipe 80 and the sub-coolant passage in the sub-coolant passage, the electric water pump 30 is stopped while the engine is stopped. Due to the pump pressure of the pump 30, the engine coolant in the sub-coolant passage does not flow into the main coolant passage through the inflow pipe 80, but circulates in the sub-coolant passage.

Further, with the three-way valve 84 shown in the modified example, the circulation place of the engine coolant during the operation of the engine and during the stop of the engine can be clearly distinguished.

[0142]

As described above, according to the present invention, the combustion heater can be reduced in size, and sufficient indoor heating can be performed even when the small combustion heater is used when the internal combustion engine is not operating. .

[Brief description of the 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 diagram showing a flow of an engine coolant.

FIG. 3 is a longitudinal sectional view showing the structure of a combustion type heater.

FIG. 4 is a longitudinal sectional view showing the structure of an EGR cooler.

FIG. 5 is a flowchart for explaining an operation control start execution routine of the combustion heater according to the first embodiment;

FIG. 6 is a schematic configuration diagram of an internal combustion engine having a combustion heater according to a second embodiment of the present invention.

FIG. 7 is a flowchart for explaining an operation control start execution routine of a combustion type heater according to a second embodiment.

FIG. 8 is a diagram showing a modification of the second embodiment.

FIG. 9 is a flowchart for explaining an operation control start execution routine of a combustion type heater according to a modification of FIG. 8;

FIG. 10 is an overall perspective view of a heater core.

FIG. 11 is a schematic configuration diagram of a third embodiment of an internal combustion engine having a combustion heater according to the present invention.

FIG. 12 is a diagram showing a modification of the third embodiment.

[Explanation of symbols]

1, 1A-1D engine (internal combustion engine) 3 Engine body 5 Intake device 7 Exhaust device 9 Intake passage 11 Throttle valve 13 Intake manifold 14 Exhaust passage 15 Exhaust manifold 17 Combustion heater 17a Engine coolant passage (for combustion type heater) 17a1 Engine coolant inlet 17a2 Engine coolant outlet 17b Combustion cylinder 17c Partition wall 17d Combustion chamber (composition of heat exchanger of combustion type heater) 17d ₁ Air supply port 17d ₂ Exhaust outlet 17e Fuel supply pipe 18 EGR 19 EGR passage (recirculation passage) 21 EGR valve 22 EGR cooler (recirculation gas cooling device, heat exchanger) 24 Heater core (heating device, heat exchanger) 25 Car air 25 'hot air 26 Radiator 28 Thermostat 30 Electric water pump (duplicate pump 32 Block 33 Air supply path 33a Inlet end of air supply path 34 Head 35 Heater exhaust gas discharge path 35a Exit end of heater exhaust gas discharge path 36 Water pump (main pump) for engine operation 40 Cooler case 40a Engine coolant outlet 40b Engine cooling liquid inlet 41 EGR gas passage forming pipe 42 Engine cooling liquid passage 43 Combustion chamber main body 43a Case body 44 Valve device (switching valve) 45 Blower fan 46 Communication passage 47 Heater exhaust gas introduction means 48 Fixed support plate 50 Flange 60 Water pipe 60a Engine coolant outlet 60a 60b Engine coolant inlet 60b 62 Fin 80 Inflow pipe (engine coolant line W3
82 ON / OFF valve 84 Three-way valve (switching valve) C1 Connection point F Flame S Space W General name of engine coolant line W1 Engine coolant line W2 Engine coolant line W3 Engine coolant line

Claims (13)

[Claims] 1. A combustion heater for raising the temperature of an engine-related element of an internal combustion engine, a recirculation system having an intake passage and an exhaust passage connected to a cylinder in a bypass manner to recirculate exhaust gas from the exhaust passage to the intake passage. A circulation passage, a recirculation gas cooling device installed in the recirculation passage for lowering the temperature of the recirculated exhaust gas, and when the internal combustion engine is in a predetermined stop state and the combustion heater needs to be operated. A heater exhaust gas introducing means for introducing a heater exhaust gas into the recirculating gas cooling device;
An internal combustion engine having a combustion type heater provided with: 2. The combustion type heater includes: an air supply path for supplying air to the combustion chamber; and an air supply path for supplying combustion air from the air supply path to the combustion chamber. A heater exhaust gas discharge path for discharging the generated heater exhaust gas from the combustion chamber; the heater exhaust gas introducing means includes: a communication path communicating the heater exhaust gas discharge path with the recirculation path; 2. A switching valve installed at a junction point joined to a discharge path and configured to switch a flow direction of heater exhaust gas discharged from the combustion heater from the heater exhaust gas discharge path to the communication path. An internal combustion engine having the combustion-type heater described in the above. 3. The recirculation passage according to claim 2, wherein a portion where the communication passage is joined to the recirculation passage is closer to an intake passage than a place where the recirculation gas cooling device is installed in the recirculation passage. An internal combustion engine having a combustion heater. 4. An EGR valve for controlling an amount of the recirculated exhaust gas is provided at a portion of the recirculation passage closer to the intake passage than a portion where the communication passage is joined, and the predetermined stop state is provided. The internal combustion engine having a combustion type heater according to claim 3, wherein the EGR valve is closed when the internal combustion engine needs to operate the combustion type heater. 5. An internal combustion engine having a combustion type heater according to claim 4, wherein an air inlet end of said air supply passage and a heater exhaust gas outlet end of said heater exhaust gas discharge passage are open to the atmosphere. 6. An air inlet end of the air supply passage and a heater exhaust gas outlet end of the heater exhaust gas discharge passage are located downstream of an installation position of an air cleaner in the intake passage for removing dirt, dust and other foreign matter in intake air. An internal combustion engine having a combustion type heater according to claim 4, wherein the internal combustion engine is connected. 7. A main pump which operates at the time of operation of the engine, a main coolant passage for circulating the engine coolant between the engine cooling system and the radiator by the operation of the pump, and a cooling system different from the main coolant passage. A liquid circulation path comprising a combustion type heater and a sub-cooling liquid path including the recirculating gas cooling device, wherein when the internal combustion engine is in the predetermined stop state, it is necessary to operate the combustion type heater 7. The internal combustion engine having a combustion heater according to claim 1, wherein the engine coolant is circulated in the sub-coolant passage but not in the main coolant passage. 8. A heating device for heating the interior of the vehicle equipped with the internal combustion engine, wherein the heating device, the combustion heater, and the recirculating gas cooling device each include a heat exchanger. The heat exchanger of the heating device is provided with the engine coolant as a heat medium when the internal combustion engine is in the predetermined stop state and needs to operate the combustion heater, and the engine coolant is directly or A heat exchanger for raising the temperature of the air by indirectly touching the air in the vehicle cabin; wherein the heat exchanger of the combustion heater and the recirculation gas cooling device includes the combustion heater and the recirculation gas cooling device. An internal combustion engine having a combustion type heater according to claim 7, wherein the heat exchanger is a heat exchanger for exchanging heat between an engine coolant and a heater exhaust gas supplied to the engine. 9. The combustion type heater according to claim 7, wherein the sub-coolant passage has a sub-pump which circulates the engine coolant in the sub-coolant passage even while the engine is stopped. Internal combustion engine. 10. The sub-coolant passage is formed of a shared portion and a non-shared portion between the sub-coolant passage and the main coolant passage. The internal combustion engine having a combustion heater according to claim 9, comprising a combustion heater, the heating device, and the sub-pump. 11. With the pump pressure of the sub-pump, with the combustion-type heater as a base point, the engine coolant flows through the sub-coolant path in the order of the combustion-type heater, the heating device, and the recirculating gas cooling device. Circulating;
0. An internal combustion engine having the combustion heater according to 0. 12. An inflow that connects the sub-coolant passage and the main coolant passage, and allows the engine coolant in the sub-coolant passage to flow from the sub-coolant passage toward a main pump of the main coolant passage. The internal combustion engine having a combustion-type heater according to claim 11, further comprising a pipe, wherein the sub-pump is disposed downstream of a connection point between the inflow pipe and the sub-coolant path in the sub-coolant path. organ. 13. An inflow that connects the sub-coolant passage and the main coolant passage, and allows the engine coolant in the sub-coolant passage to flow from the sub-coolant passage toward the main pump of the main coolant passage. A switching valve is provided at a connection point between the inflow pipe and the sub-coolant liquid path, and the sub-pump is arranged upstream of the switching valve installation point in the sub-coolant liquid path; The switching valve is switched to flow the engine coolant flowing through the sub-coolant passage into the inflow pipe, and the engine coolant is supplied to the sub-coolant passage and the main coolant passage by both pump pressures of the sub-pump and the main pump. The combustion type heater according to claim 11, wherein when the engine is stopped, the switching valve is switched to circulate the engine coolant only through the sub-coolant passage by the pump pressure of the sub-pump. Internal combustion engine .