JP3528603B2 - 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 No. 62-75069, the internal combustion engine is started in cold weather by warming the engine cooling water by utilizing the combustion heat generated by a combustion type heater installed in the intake passage of the internal combustion engine. It shows the technology to improve heat transfer and 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 is supplied from the intake passage via the intake duct, and the combustion gas is discharged to the intake passage via the exhaust duct. The high-temperature combustion gas produced by the combustion heater is
After passing through the intake passage, it reaches the internal combustion engine body and warms the engine cooling water in the water jacket. In addition, of the intake passage,
An on-off valve for opening and closing the intake passage, a so-called intake throttle valve, is provided between the connection point with the intake duct and the connection point with the exhaust duct. The intake throttle valve is fully closed before the internal combustion engine is started, and is half closed (half open) or fully opened for a while after the start of the internal combustion engine to adjust the supply amount of the combustion air to the combustion heater. By this adjustment, warm-up of the internal combustion engine is promoted and startability is improved.

On the other hand, although not described in the above publication, it is conceivable to equip the exhaust system of the internal combustion engine with a catalytic converter as an exhaust purification means. In this case, in order for the catalyst of the catalytic converter to function effectively, it is necessary to raise the temperature of the catalyst to a temperature at which it functions effectively. Therefore, for example, if the internal combustion engine is placed in an idling state and the temperature of the exhaust gas emitted from the internal combustion engine is raised at that time, the temperature of the exhaust passage also rises accordingly, so the catalyst functions faster and the internal combustion engine Exhaust gas can be purified faster.

[0005]

By the way, in order to raise the temperature of the exhaust gas emitted from the internal combustion engine, simply burning a large amount of fuel in the combustion chamber is sufficient. However, in the case of idling, usually, a large amount of fuel is not burned during idling, and instead, the throttle amount of the intake throttle valve is increased to reduce the intake amount, that is, the air supplied to the cylinder of the internal combustion engine. The amount of fuel is increased relative to the amount. However, in that case, the intake resistance in the intake passage increases, and the differential pressure between the intake side and the exhaust side of the combustion heater increases. For this reason, the velocity of the air flowing through the combustion heater becomes high, and it is similar to that it is difficult for the lighter and the match to catch fire in strong winds. is there. Also,
If the type of flame is difficult to form or if it disappears immediately, the A / F of the combustion type heater set for each vehicle type or type of internal combustion engine will deviate significantly from a predetermined value, which is not preferable.

Further, when the intake throttle valve is throttled, the amount of intake air entering the cylinder of the internal combustion engine decreases, so that the air density, that is, the oxygen mass decreases. Therefore, smoke is likely to be generated when the internal combustion engine burns. That is, the emission may deteriorate. The present invention has been made in view of the above circumstances, and has the following effects in an internal combustion engine that has a combustion heater to promote warm-up of the internal combustion engine and improve startability. It is a technical object to provide an internal combustion engine having a combustion-type heater capable of performing the above. Ensure the ignition type of the combustion heater. Prevent emission deterioration. Improves exhaust gas purification.

[0007]

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) A combustion chamber, an air supply path for supplying combustion air to the combustion chamber, a fuel supply path for supplying combustion fuel to the combustion chamber, and the combustion supplied by the fuel supply path into the combustion chamber. A combustion-type heater comprising: an ignition device for igniting fuel; and a combustion gas discharge passage for discharging combustion gas emitted from the combustion fuel, which is burned in the combustion chamber by the ignition by the ignition device, from the combustion chamber. In an internal combustion engine having a combustion heater that operates when the engine is in a predetermined operating state and raises the temperature of an engine-related element, the combustion heater is provided with respect to an intake passage of the internal combustion engine, the air supply passage, and the combustion passage. And a combustion gas discharge passage, which are connected in a bypass manner, and the suction passage that flows through the intake passage downstream of the connection portion of the combustion heater with the intake passage in the intake passage. Characterized by installing an intake throttle valve to control the amount of.

Here, the "predetermined operating state of the internal combustion engine" means that when the internal combustion engine is operating, after the internal combustion engine is started, or when the internal combustion engine itself generates a small amount of heat during cold weather or extremely cold weather ( For example, when fuel consumption is low) and when the internal combustion engine itself has a small amount of heat generation, the amount of heat received by the cooling water is small, and cold time means a temperature of about -10 ° C to 15 ° C.
Extreme cold is a temperature of -10 ° C or lower.

"Engine-related elements" means engine cooling water,
It is the internal combustion engine itself that introduces the combustion gas of the combustion heater into the intake air.

In the internal combustion engine having the combustion heater according to the present invention, an intake throttle valve for controlling the amount of intake air flowing through the intake passage is installed in the intake passage downstream of the connection point between the combustion heater and the intake passage. Therefore, of the intake passage,
There is no intake throttle valve between the connection point with the air supply path and the connection point with the combustion gas discharge path. Therefore, in the portion of the intake passage between the portion where the air supply passage is connected to the intake passage and the portion where the combustion gas discharge passage is connected to the intake passage, a pressure difference occurs regardless of whether the intake throttle valve is operating. Absent. Therefore, the air velocity in the combustion heater main body connected to the intake passage via the air supply passage and the combustion gas discharge passage does not become excessive. Therefore, strong ventilation is not generated in the combustion chamber to the extent that the combustion heater cannot be ignited, so that the combustion heater can be reliably ensured.

Further, since the type of fire can be reliably secured, the A / F of the fuel combustion heater set for each type of vehicle or type of internal combustion engine does not deviate from a predetermined value. (2) In the above (1), the intake throttle valve may be a throttle valve for controlling the output of the internal combustion engine. (3) In the above (1), the intake throttle valve may be a throttle valve for controlling the state of the internal combustion engine. (4) In the above (1) to (3), it is preferable that the connection point of the air supply passage with the intake passage is located upstream of the connection point of the combustion gas discharge passage with the intake passage. Since the air supply passage and the combustion gas discharge passage of the combustion heater do not directly open to the atmosphere, a noise reduction effect can be expected. (5) In the above (1) or (4), the internal combustion engine has a catalyst in its exhaust system, and when there is a request to raise the temperature of this catalyst, the intake throttle valve is throttled and at least the intake throttle is used. It is preferable that the combustion heater is activated when the valve is throttled.

Here, "when there is a request to raise the temperature of the catalyst" means that it is necessary to raise the catalyst temperature depending on the condition of the internal combustion engine.・ CPU (Central Unit), which is the center of the control unit
Processing unit), specifically, during cold weather, which is a temperature of about -10 ° C to 15 ° C, or
When the internal combustion engine is operating, after starting the internal combustion engine, or when the amount of heat generated by the internal combustion engine itself is low (for example, when fuel consumption is low) during extremely cold temperatures that are 10 ° C or lower.
And the amount of heat received by the cooling water is small due to the small amount of heat generated by the internal combustion engine itself, for example, when the engine 1 is in the idling state.

In this case, in the internal combustion engine having the combustion heater according to the present invention, the intake throttle valve is throttled when the catalyst temperature is required to be increased, and at least when the intake throttle valve is throttled. Since the heater operates, it is not necessary to throttle the intake throttle valve to raise the temperature of the exhaust gas, and the high temperature combustion gas flowing from the combustion heater to the combustion chamber of the internal combustion engine causes Warm enough. Therefore, since the temperature in the cylinder of the internal combustion engine can be raised without increasing the degree of throttling of the intake throttle valve, it is not necessary to greatly throttle the intake throttle valve as in the conventional techniques. Therefore, the amount of intake air that enters the cylinder of the internal combustion engine does not decrease significantly, so that smoke can be suppressed. Therefore, the emission does not deteriorate. (6) In the above (5), the operation of the combustion heater may precede the closing of the intake throttle valve.

In this case, since the combustion type heater operates prior to the closing of the intake throttle valve, the temperature of the internal combustion engine due to the combustion gas emitted by the combustion type heater is detected by, for example, a cooling water temperature sensor or the like, and in response thereto. If the intake throttle valve closing control is performed in this manner, the intake throttle valve closing control can be performed in a state where the amount of smoke generated is the smallest.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. <First Embodiment> (Engine 1) The engine 1 as an internal combustion engine is a water-cooled engine, and an engine body 3 having a water jacket (not shown) through which cooling water, which is one of the engine-related elements, circulates.
And an intake device 5 for sending air required for combustion into a plurality of cylinders (not shown) of the engine body 3, and a mixture of the air of the intake device 5 and fuel injected by a fuel injection device (not shown). It has an exhaust device 7 that discharges exhaust gas after it is burned into the atmosphere, and a vehicle interior heater 9 that warms the interior of the vehicle in which the engine 1 is mounted.

(Intake device 5) The intake device 5 has an air cleaner 13 for taking in fresh air into the cylinder as a start end of the intake device 5 and an intake port (not shown) of the engine body 3 as an end. In the meantime, an air flow meter 14, a compressor 15a of the turbocharger 15 which is an intake system structure, a combustion heater 17 that burns under atmospheric pressure, an intercooler 19, an intake throttle valve 20 and an intake manifold 21 are provided.

These intake system structures belong to the intake pipe 23 which is another one of the intake system structures and which is an intake passage having a plurality of pipes.

(Intake Pipe 23) The intake pipe 23 has a downstream connecting pipe 27 which is in a pressurized state since the outside air entering the intake device 5 is forcibly pushed by the compressor 15a with the compressor 15a as a boundary. It can be roughly classified into the upstream side connecting pipe 25 which is not so.

(Upstream Side Connection Pipe 25) One upstream side connection pipe 25 is a rod-shaped main flow pipe 29 extending straight from the air cleaner 13 toward the compressor 15a in FIG.
And a heater branch pipe 31 as a tributary pipe connected to the main flow pipe 29 in a bypass manner.

(Main flow pipe 29) The main flow pipe 29 has the air flow meter 14 and the outside air temperature sensor 32 at the center thereof. The air flow meter 14 will be described later,
The outside air temperature sensor 32 will be described next.

(Outside air temperature sensor 32) An outside air temperature sensor 32 is provided in a portion of the main flow pipe 29 near the downstream side of the air cleaner 13.
Is installed. The outside air A entering the main pipe 29 from the air cleaner 13 is the engine 1 and the combustion heater 17.
The ambient temperature sensor 32 detects the temperature of the fresh air.

(Heater branch pipe 31) Heater branch pipe 31
Has a substantially "U" shape as a whole, and includes a combustion heater 17 in the middle thereof. Also, the heater branch pipe 31
As another component, the upstream side portion of the combustion type heater 17 in the air flow direction is connected to the mainstream pipe 29, and new air is supplied from the mainstream pipe 29 to the combustion type heater 17, that is, the combustion type heater 17 is burned. Combustion gas from the combustion heater 17 that connects the air supply pipe 33 as an air supply passage for supplying air (pre-combustion air) a1, the downstream side portion of the combustion heater 17 in the air flow direction, and the main flow pipe 29. (Post-combustion air) a2 and a combustion gas discharge pipe 35 as a combustion gas discharge passage for discharging the main flow pipe 29. Therefore, the heater branch pipe 31 includes the air supply pipe 33 and the combustion gas discharge pipe 35.
Air is supplied to and discharged from the combustion heater 17 via the. Further, the air supply passage 33 and the combustion gas introduction passage 35 are
Since they are used only for the combustion heater 17, they can be said to be members belonging to the combustion heater 17.

(Connection points c1 and c2) Air supply pipe 3
Among the connection points c1 and c2 of the combustion gas exhaust pipe 35 and the main gas pipe 29, the connection point c1 is located on the upstream side of the main flow tube 29 with respect to the connection point c2. Therefore, the outside air (fresh air) A from the air cleaner 13 first branches into the heater fresh branch pipe 31 at the connection point c1.
(Hereinafter, simply referred to as “air a1”) and air a1 ′ that does not branch and heads the main pipe 29 toward the connection point c2. The air a1 branched at the connection point c1 is the air supply pipe 3
3-Combustion type heater 17-Combustion gas a2 is returned from the connection point c2 to the main flow pipe 29 via the combustion gas discharge pipe 35. Further, the combustion gas a2 and the air a1 'merge at the connection point c2 to form combustion gas mixed air a3.
The combustion gas mixed air a3 is provided as combustion air in the cylinder of the engine body 3. In general, the combustion gas of the combustion heater is a gas that has almost no smoke in a normal combustion state, in other words, a gas containing no carbon, and the combustion gas of the combustion heater 17 according to this embodiment is also the same. Therefore, there is no problem even if the combustion gas a2 of the combustion heater 17 is used as intake air for the internal combustion engine.

(Downstream Connection Pipe 27) Downstream Connection Pipe 27
1 is a pipe connecting the compressor 15a and the intake manifold 21, as shown in FIG. 1, and is L-shaped in this embodiment. An intercooler 19 and an intake throttle valve 20 are arranged in the central portion of the downstream side connecting pipe 27 and in the portion near the intake manifold 21, respectively.

(Intercooler 19) Intercooler 1
The reference numeral 9 cools the compression heat generated when the intake air is compressed by the compressor 15a, thereby preventing a decrease in the output of the internal combustion engine due to a rise in intake air temperature.

(Intake throttle valve 20) Since the intake throttle valve 20 is attached to the portion close to the intake manifold 21 as described above, the intake pipe 23 is more detailed than the connection portion of the combustion type heater 17 in the intake pipe 23. Is located downstream of the connection point c2 between the combustion gas exhaust passage 35 and. The intake throttle valve 20 is an intake amount control valve that controls the amount of intake air flowing through the intake pipe 23. By controlling the intake amount by the intake throttle valve 20, the output of the engine 1 is controlled, or the operating state of the engine 1 such as stopping the engine 1 is controlled. Furthermore, when there is a request to raise the catalyst temperature of the later-described catalytic converter 39 belonging to the exhaust device 7, that is, depending on the condition of the engine 1, it is necessary to raise the catalyst temperature of the catalytic converter 39. When the computer that controls the entire engine 1, that is, the CPU that is the central portion of the ECU 46 determines, the intake throttle valve 20 is throttled. When it is necessary to raise the catalyst temperature, it means that the internal combustion engine is operating, or after the internal combustion engine is started, or when the internal combustion engine itself has a small amount of heat during cold or extremely cold (for example, fuel consumption is low. Time) and the amount of heat received by the internal combustion engine is small, so the amount of heat received by the cooling water is small, for example, when the engine 1 is in the idling state. Also,
The cold time is a temperature of about -10 ° C to 15 ° C, and the extremely cold time is a temperature of -10 ° C or lower. Note that the case where it is necessary to raise the catalyst temperature is referred to as "when there is a request for exhaust gas temperature rise control" for convenience. Also,
When there is a request for this exhaust gas temperature increase control, the engine 1 is brought into an operating state in which the combustion heater 17 needs to be activated.
It may be said that there is.

(Exhaust device 7) On the other hand, the exhaust device 7 has an exhaust system structure that has an exhaust port (not shown) of the engine body 3 as a start end of the exhaust device 7 and a muffler 41 which is the end of the exhaust device 7. An exhaust manifold 38, which is an object, a turbine 15b of the turbocharger 15, and a catalytic converter 39 having a catalyst are provided on an exhaust pipe 42 which is also an exhaust system structure. The air flowing through the exhaust device 7 is indicated by the symbol a4 as the exhaust gas of the engine 1.

(Combustion heater 17) Next, the combustion heater 1
The structure of 7 is shown schematically in FIGS.

The combustion type heater 17 is designed so that the CPU controls the combustion state thereof, and operates when the intake throttle valve 20 needs to be throttled.

The combustion heater 17 is connected to the water jacket of the engine body 3, and the combustion heater 17 has an engine cooling water passage 17a therein through which the engine cooling water from the water jacket passes. The engine cooling water (shown by the broken line arrow in FIG. 2) flowing through the engine cooling water passage 17 a is the combustion chamber 1 formed inside the combustion heater 17.
It passes around 7d so that the combustion chamber 1
It receives heat from 7d and gets warm.

(Combustion chamber 17d) The combustion chamber 17d is composed of a combustion cylinder 17b as a combustion chamber that emits a flame, and a cylindrical partition wall 17c that covers the combustion cylinder 17b to prevent the flame from leaking to the outside. By covering the combustion cylinder 17b with the partition wall 17c, the combustion chamber 17d is defined within the partition wall 17c. And
The partition wall 17c is also covered with the outer wall 43a of the combustion heater 17,
There is a gap between them. By setting this interval,
The engine cooling water passage 17a is formed between the inner surface of the outer wall 43a and the outer surface of the partition wall 17c.

Further, the combustion chamber 17d is provided with the air supply pipe 3
3 has an air supply port 17d1 and an exhaust gas outlet 17d2 which are directly connected to the combustion gas exhaust pipe 35.

From the air supply pipe 33 to the air supply port 1
The air a1 that has entered the combustion chamber 17d via 7d1 reaches the exhaust gas outlet 17d2 via the combustion chamber 17d, and then from the combustion gas exhaust pipe 35 to the main pipe 29 as the combustion gas a2 as described above. Flow in. Therefore, the combustion chamber 17d
Is in the form of a series of air flow passages for passing the air a1 that changes into the combustion gas a2 in the combustion heater 17.

After the combustion type heater 17 burns, the combustion gas a2 is returned to the main flow pipe 29 via the combustion gas discharge pipe 35.
Is, so to speak, a combustion gas discharged from the combustion heater 17, and thus has heat. Then, until the combustion gas a2 having this heat is discharged from the combustion heater 17 to the combustion gas discharge pipe 35, the heat of the combustion gas a2 is converted to the engine cooling water flowing through the partition wall 17c in the engine cooling water passage 17a. It is transmitted and warms the engine cooling water as described above, and the warmed engine cooling water is sent to the water jacket of the engine 1 to warm up the engine body 3.

(Combustion cylinder 17b) Further, the combustion cylinder 17b is
Fuel supply pipe 17 connected to a fuel pump (not shown)
e, from which the pump pressure of the fuel pump is received to supply combustion fuel to the combustion cylinder 17b. Therefore, the fuel pump and the fuel supply pipe 17e can be regarded as fuel supply means. The fuel supply amount by the operation of the fuel pump is the integrated value of the fuel supply amount from the start of the operation of the fuel pump as the combustion heater 1.
It is temporarily stored in the RAM (random access memory) of the ECU 46 that controls the combustion state of the ECU 7, and is called to the CPU, which is the central portion of the ECU 46, if necessary.

(Liquefied fuel 18) The combustion fuel to be supplied is
The liquefied fuel 18 is turned into vaporized fuel 18 'through the fuel vaporization section 17f shown in FIG. 3. The vaporized fuel 18' is ignited by a glow plug 17g which is an ignition device and generates heat by energization from a battery (not shown). . When the glow plug 17g generates heat, the actual time elapsed from the start of energization is counted by the timer Tim (see FIG. 1), and the value is also temporarily stored in the RAM. Then, it calls the CPU as necessary.

(Ion Sensor 17h and Fuel Heating Evaporation Plate 17i) Reference numerals 17h and 17i in FIG. 3 are an ion sensor serving as an ignition sensor and a fuel heating evaporation plate, respectively. The vaporized fuel 18 ′ is ignited in the vicinity of the fuel heating / evaporating plate 17i, and a fire type F ′ which is a source of the flame F is formed. The blower fan 45 grows the flame F ′ into flame.

(Blower Fan 45) The blower fan 45 is located upstream of the combustion chamber 17d in the form of an air flow passage.
The output of the blower fan 45 is adjusted by controlling its operation by the CPU of the ECU 46. This output adjustment changes the amount of air flowing in the combustion chamber 17d. Therefore, the amount of air flowing in the combustion chamber 17d can be controlled by adjusting the output of the blower fan 45.

(Circulation of Engine Cooling Water) Next, the circulation of the engine cooling water to the engine cooling water passage 17a will be described with reference to FIGS.
Will be described with reference to.

(Engine Cooling Water Passage 17a) The engine cooling water passage 17a is provided with a cooling water inlet 17a1 connected to the water jacket of the engine body 3 and an engine cooling water outlet 17a2 connected to the vehicle interior heater 9. Have and.

(Water pipelines W1 to W3) Engine cooling water inlet 1
7a1 and the engine body 3 are connected to each other with a water pipe W1 interposed therebetween, and the engine cooling water discharge port 17a2 and the vehicle interior heater 9 are connected to each other via a water pipe W2.

The combustion heater 17 is connected to the water jacket of the engine body 3 and the vehicle interior heater 9 via the water conduit W1 and the water conduit W2.
In addition, the vehicle interior heater 9 and the engine body 3 are also connected via a water conduit W3.

Therefore, the engine cooling water in the water jacket of the engine body 3 flows in the order of flow from the engine cooling water inlet 17a1 to the combustion heater 17 via the water conduit W1 and is heated there. The warmed engine cooling water reaches the vehicle interior heater 9 from the engine cooling water discharge port 17a2 of the combustion type heater 17 through the water pipe W2. Then, after the engine cooling water is heat-exchanged by the vehicle interior heater 9 and the temperature thereof drops, the engine cooling water returns to the water jacket via the water conduit W3. A water temperature sensor 47 for detecting the engine cooling water temperature is attached to the water jacket.

As described above, the engine cooling water is supplied to the water pipe W1.
Through the water conduit W2 and the water conduit W3 to circulate between the engine body 3, the combustion heater 17, and the vehicle interior heater 9.

(Electrical connection of sensor etc. to ECU 46)
Further, the ECU 46 uses the ion sensor 17h, the outside air temperature sensor 32 and the water temperature sensor 47, the timer Tim,
It is electrically connected to the blower fan 45 and the fuel pump. Then, the CPU appropriately controls the combustion state of the combustion heater 17 in accordance with the output values of the sensors 17h, 32 and 47, the timer Tim, the output value of the blower fan 45, the fuel pump, etc. 17
Maintain the flame momentum, size, temperature, etc. in an optimal state.
Further, the temperature of the exhaust gas of the combustion heater 17 and the air-fuel ratio of the combustion heater 17 are adjusted by controlling the combustion state of the combustion heater 17 by the CPU. Further, the CPU controls the combustion heater 17 and the throttle degree of the intake throttle valve 20 in accordance with the above parameters.

(Air flow meter 14) Also, the main flow pipe 29
The air flow meter 14 installed in the main flow pipe 29 is located between the connection point c1 of the intake air supply passage 33 and the connection point c2 of the combustion gas introduction passage 35 in the main flow pipe 29.

By the way, in general, the air flow meter is an air resistance substance that obstructs the flow of the air flowing through the intake passage, so the pressure of the air flowing out of the air flow meter is smaller than the pressure of the air entering the air flow meter. That is, the air flow meter has a difference between the air pressure at its inlet and the air pressure at its outlet. In this way, an air flow meter, which is an intake resistance substance having a difference in air pressure between the inlet and the outlet, is installed in the main pipe 29.
In the main line portion for the combustion heater 17 connected in a bypass manner with respect to the main flow pipe 29, that is, in the main flow pipe 29, the connection point c1 between the main flow pipe 29 and the air supply passage 33 and the connection point c2 between the main flow pipe 29 and the combustion gas introduction passage 35. Part 29 between
When it is provided in m, since the differential pressure is large at the connection points c1 and c2, that is, at the inlet of the air supply passage 33 and the outlet of the combustion gas introduction passage 35, there is a gap between the air supply passage 33 and the combustion gas introduction passage 35. There is a possibility that the air flow velocity in the combustion chamber 17d of the combustion-type heater 17 located is excessively high and the ignitability deteriorates.

Therefore, the air flow meter is preferably a hot wire type or film type air flow meter having a small pressure difference between the inlet side and the outlet side.

(Operation Control Execution Routine of Intake Throttle Valve 20) Next, the operation control execution routine of the intake throttle valve 20 will be described with reference to FIG.

This routine is a part of a normal flow chart (not shown) for driving the engine 1, and includes steps S101 to S103 described below. The flow chart including these steps is the RO of the ECU 46.
It is stored in M. The processing in each step of each flowchart is all performed by the CPU of the ECU 46. Note that the symbol S is used, for example, in step 10
If it is 1, it is abbreviated as S101.

After the engine 1 is started, when the processing shifts to this routine, first, in S101, the engine 1 is in the operating state in which it is necessary to set the exhaust temperature increase control request flag, that is, the combustion type heater 17 is required to be activated. Determine if there is. In this case, the temperature of the engine cooling water is naturally low, and the case where the engine cooling water temperature is lower than a predetermined temperature, for example, 60 ° C. will be exemplified as the case where the combustion heater 17 needs to be activated.

The temperature of the engine cooling water is detected by the water temperature sensor 47 associated with the water jacket of the engine body 3. S
If an affirmative decision is made in 101, the operation proceeds to S102. In S102, it is determined whether or not the combustion heater 17 is operating, that is, whether or not combustion is performed by emitting a flame.

Further, if the temperature of the engine cooling water is higher than the predetermined temperature exemplified as 60 ° C., it means that the engine 1 is in an operating state in which the combustion heater 17 does not need to be activated. A determination is made and this routine ends.

In S103, the closing control of the intake throttle valve 20 is executed.

The above is the engine 1 having the combustion heater 17 according to the embodiment of the present invention.

<Operation and Effect of Embodiment> Next, the operation and effect of the embodiment of the present invention will be described.

In the engine 1, the intake throttle valve 20 is installed in the intake pipe 23 downstream of the location where the combustion heater 17 is installed. Therefore, the intake throttle valve 20 does not exist in the portion 29m of the main flow pipe 29 of the intake pipe 23 between the connection point c1 with the air supply passage 33 and the connection point c2 with the combustion gas discharge passage 35. Therefore, the air supply passage 35 and the combustion gas discharge passage 3 which are respectively connected to the intake pipe 23.
Between 5 and 5, regardless of whether the intake throttle valve 20 is operated,
There is no pressure difference. Therefore, the air velocity in the combustion chamber 17d of the combustion heater 17 connected to the intake pipe 23 via the air supply passage 33 and the combustion gas discharge passage 35 does not become excessive. Therefore, strong ventilation is not generated in the combustion chamber 17d to the extent that the combustion heater 17 cannot be ignited, so that the combustion type F'of the combustion heater 17 can be reliably ensured.

Further, since the fire type F'can be reliably secured,
The A / F of the fuel combustion heater set for each vehicle type or engine type does not deviate from a predetermined value.

Further, the air supply passage 3 of the combustion type heater 17
Since 3 and the combustion gas discharge passage 35 are not directly opened to the atmosphere, a noise reduction effect can be expected.

Furthermore, in the engine 1, when the exhaust temperature rise control is requested, the intake throttle valve 20 is throttled and, at least at this time, the combustion heater 17 operates, so the intake throttle valve 20 is throttled. Without raising the temperature of the exhaust gas of the engine 1, the combustion heater 17 sufficiently warms the combustion chamber by the high-temperature exhaust gas flowing into the combustion chamber of the engine 1. Therefore, the in-cylinder temperature of the engine 1 can be increased without increasing the throttle of the intake throttle valve 20, and it is not necessary to increase the in-cylinder temperature by significantly reducing the intake amount. Therefore, since the generation of smoke from the engine 1 can be suppressed, the emission does not deteriorate.

The operation of the combustion heater 17 precedes the closing control of the intake throttle valve 20. Therefore, if various temperatures related to the engine 1 due to the combustion gas emitted from the combustion heater 17 are detected by various temperature sensors and the intake throttle valve closing control is performed according to the detected temperature, the degree of closing of the intake throttle valve 20 is smoked. It can be controlled in the state where the amount generated is the smallest.

[0062]

As described above, in the internal combustion engine having the combustion type heater of the present invention, the combustion type of the combustion type heater is surely secured, and the exhaust gas is purified well while preventing the deterioration of the emission. Can be

[Brief description of drawings]

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

FIG. 2 is a schematic sectional view of a combustion heater according to an embodiment of the present invention.

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

FIG. 4 is a flowchart of an intake throttle valve operation control execution routine according to the embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine (internal combustion engine) 3 ... Engine main body (main body of internal combustion engine) 5 ... Intake device 7 ... Exhaust device 9 ... Cabin heater 13 ... Air cleaner 14 ... Air flow meter 15 ... Turbocharger 15a ... Compressor 15b ... Turbocharger Turbine 17 ... Combustion heater 17a ... Combustion heater engine cooling water passage 17a1 ... Engine cooling water inlet 17a2 ... Engine cooling water outlet 17b ... Combustion cylinder (combustion chamber) 17c ... Cylindrical partition 17d ... Combustion chamber 17d1 ... Air Supply port 17d2 ... Exhaust discharge port 17e ... Fuel supply pipe (fuel supply means) 17f ... Fuel vaporization part 17g ... Glow plug (ignition device) 17h ... Ion sensor 17i ... Fuel heating evaporation plate 18 ... Liquefied fuel 18 '... Vaporized fuel 19 ... Intercooler 20 ... Intake throttle valve 21 ... Intake manifold 23 ... Intake pipe 25 ... Upstream connecting pipe 27 ... Downstream connecting pipe 29 ... Main flow pipe 29m ... Portion 31 between connection points c1 and c2 in the main flow pipe ... Heater branch pipe 32 ... Outside air temperature sensor 33 ... Air supply pipe (air supply passage) 35 ... Combustion gas discharge pipe (Combustion gas exhaust passage) 38 ... Exhaust manifold 39 ... Catalytic converter 41 ... Muffler 42 ... Exhaust pipe 43a ... Outer wall 45 ... Blower fan 46 ... ECU 47 ... Water temperature sensor W1 ... Water pipe W2 ... Water pipe W3 ... Water pipe F ... Flame F ′ ... Fire type Tim ... Timer A ... Outside air a1 ... Branching from outside air A at connection point c1 and air supply pipe 3
Air flowing through 3 (fresh air) a1 '... Air heading the main pipe 29 toward the connection point c2 ... Combustion gas a3 of combustion heater 17 ... Combustion gas mixed air a4 of combustion gas a2 and air a1' ... Engine 1 Exhaust gas c1 ... Connection point between air supply pipe 33 and main flow pipe 29 (connection point of air supply passage with the intake passage) c2 ... Connection point between combustion gas discharge passage 35 and main flow pipe 29 (of combustion gas discharge passage) (Connection point with the intake passage)

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) F02N 17/06

Claims (6)

(57) [Claims] 1. A combustion chamber, an air supply path for supplying combustion air to the combustion chamber, a fuel supply path for supplying combustion fuel to the combustion chamber, and a fuel supply path for supplying fuel to the combustion chamber. A combustion heater comprising: an ignition device for igniting the combustion fuel; and a combustion gas discharge passage for discharging combustion gas emitted from the combustion fuel, which is burned in the combustion chamber by the ignition by the ignition device, from the combustion chamber. In an internal combustion engine having a combustion heater that operates when the internal combustion engine is in a predetermined operating state to raise the temperature of an engine-related element, the combustion heater is provided with respect to an intake passage of the internal combustion engine,
The air supply passage, the combustion chamber, and the combustion gas discharge passage are connected in a bypass shape, and the air supply passage of the combustion heater is included in the intake passage.
Wherein downstream of the connecting portion between the connecting portion and the combustion gas discharge passage between the intake passage and <br/> the intake passage, established the intake throttle valve to control the amount of intake air flowing through the intake passage and the The air supply passage of the combustion heater in the intake passage
And a connection point between the intake passage and the combustion gas discharge passage
An intake throttle valve exists between the connection points with the intake passage.
Without, the combustion heater enters from the air supply passage and the combustion
The blower fan that controls the amount of air flowing through the room
An internal combustion engine having a combustion heater, characterized by being provided upstream of the chamber . 2. The internal combustion engine having a combustion heater according to claim 1, wherein the intake throttle valve is a throttle valve for controlling the output of the internal combustion engine. 3. The internal combustion engine having a combustion heater according to claim 1, wherein the intake throttle valve is a throttle valve for controlling the state of the internal combustion engine. 4. The connection point of the air supply passage with the intake passage is located upstream of the connection point of the combustion gas discharge passage with the intake passage. An internal combustion engine having the combustion heater according to any one of 1. 5. The internal combustion engine has a catalyst in its exhaust system, and throttles the intake throttle valve when there is a demand for increasing the temperature of the catalyst, and at least when the intake throttle valve is throttled, the combustion type An internal combustion engine having a combustion heater according to claim 1 or 4, wherein the heater is operating. 6. The internal combustion engine having a combustion heater according to claim 5, wherein the operation of the combustion heater precedes the closing of the intake throttle valve.