JPS6111413A - Regenerating device of diesel particulate filter - Google Patents

Abstract

PURPOSE:To enable a flow of secondary air to be accurately controlled, by providing a relief valve setting to a fixed value a difference between pressure before and after a flow control valve variably forming a flow path area in a supply path of air to a burner. CONSTITUTION:A flow control valve 28, being providing in a supply path 21 feeding air to burner device 20 through an air supply device 9, is driven by a flow control device 23 in accordance with a temperature or a pressure of the air in the supply path 21. A relief valve 34 releasing the air to the atmosphere from said path 21 is mounted to the secondary flow path 21. If a difference between pressure beore and after the flow control valve 28 exceeds the valve opening force generated by a compression spring 45, a valve body 35 moves in a valve opening direction P by closing an opening 48 in a pip 44.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a burner no-air control device used for re-combustion of a diesel particulate filter.

To prevent pollution, the particulates emitted by diesel engines are removed from the exhaust by a diesel particulate filter (hereinafter simply referred to as a filter), which is usually made of ceramics. It is removed as a non-polluting substance by combustion. Moderate combustion>I for re-burning of this particulate
Air is required to maintain a certain amount of oxygen and a certain amount of excess air.If the heating temperature is too low, particulate matter (particulate matter) will not be removed, and on the other hand, if heated too much, the filter itself will melt. There is this inconvenience.

By the way, burners are often used as heating sources for filters, and in particular, atomizing type burners are often used, which atomize the fuel using primary air at a high pressure and receive a large flow rate, and burn particulates using secondary air at a low pressure and large flow rate. has been done. The optimum supply meter of primary air supplied to the burner is approximately proportional to the fuel flow rate, and in order to keep this fuel flow rate constant, the primary air amount is usually kept constant. On the other hand, secondary air is required to have a low pressure but a large flow rate, and must be controlled so that only a predetermined weight flow rate value necessary for combustion of particulates is supplied. This secondary air is usually 2,
The air pump is supplied using a positive displacement air pump, and the volumetric flow m is constant if only the rotational speed is kept constant, but the weight flow rate changes depending on changes in atmospheric pressure, atmospheric temperature, and ennon pressure. It's easy. For this reason, the advantage of a positive displacement air pump, which is ensuring a large output volume, is utilized.

Changes in weight flow rate need to be corrected. For example, a general positive displacement air pump has characteristics as shown in FIGS. 1 to 6.

FIG. 1 shows an example of the volumetric flow rate-discharge pressure characteristic of a positive displacement air pump, and it is clear that by narrowing down the passage area on the discharge side, the volumetric flow rate is reduced, while the discharge pressure increases relatively greatly. Furthermore, Fig. 2 shows an example of the weight basis weight vs. output pressure characteristics when the positive displacement air pump is located at a low altitude (indicated by a solid line) and at a high altitude (indicated by a broken line). ie lower the discharge pressure at high altitudes.

It is shown that it is necessary to widen the restriction of the air supply path from low-lying areas and lower the positive pressure. Similarly, as shown in Figure 3, the pump itself fluctuates even at a constant altitude.

It is shown that the weight flow rate varies depending on the atmospheric temperature, etc., as shown by the two broken lines.

An example of a conventional device using a positive displacement air pump having such characteristics as a secondary air pump is shown in FIG. 4. A diesel engine (hereinafter simply referred to as engine) 1 includes a Kuho charger 2, a filter 5 on the downstream side of an exhaust path 6, and discharges exhaust gas through a muffler 200 on the downstream side. 4 is a burner provided upstream of the exhaust path 3 of the filter 5, and the burner 4 is connected to the ignition coil 6.
The fuel from the fuel pump 8 is atomized by the F from the primary air pump 7, which is metered by the pressure regulating valve 201, and the air from the secondary air pump 9 is used to atomize the excess air in the high-temperature gas. It is configured to maintain the rate at a predetermined value and burn the particulates with excess oxygen. The flow area of the secondary air supply path 10 is increased or decreased by a flow rate control valve 11, and the vacuum chamber that opens and closes this valve is controlled by a vacuum pump 12, which is a negative pressure source, and a vacuum adjustment valve 1.
6 and a solenoid valve 14.

Further, in such a system, it is necessary to prevent the flow of exhaust gas from affecting the regeneration of particulates. For this reason, as shown in FIG. An exhaust switching valve 210 is provided at the upstream branch point of the bypass path 202. The exhaust switching valve 210 has a diaphragm 2 connected to the vacuum pump 12.
03 via a link mechanism.

A solenoid valve 204 is provided between the diaphragm 203 and the vacuum pump 12. The solenoid valve 204 has a valve body 205
It is composed of a coil 206 and a spring 207, and when a current flows through the coil 206, the valve body 205 closes the coil 206.
The solenoid valve 204 is opened. Then, the negative pressure of the vacuum pump 12 acts on the diaphragm 203, and the exhaust switching valve 210 moves from the position a to the position b, closing the exhaust passage 6. As a result, the exhaust gas emitted from the engine 1 passes through the exhaust bypass passage 202 and reaches the muffler 202.
0, thereby preventing the exhaust gas from the engine 1 from affecting the combustion conditions of the combustion engine 20.

In addition, numeral 17 is a fuel adjustment valve, and numeral 18 is a pressure adjustment valve of 1 m!
Valve, code 15 ignition filter 6. F pump 7.9. A controller controls the solenoid valve 14 and the fuel adjustment valve 17, and reference numeral 16 indicates an atmospheric pressure sensor.

If excessive adhesion occurs on the filter 5I of the engine 1, the controller 15 detects, for example, through the pressure sensor 19 that the exhaust passage pressure on the upstream side of the filter 5 exceeds a set value. , initiates reburning. In this case, if the atmospheric pressure is low at a high altitude, the controller 15 outputs an input signal from the atmospheric pressure sensor 16 to the solenoid valve 14 to control the flow area of the secondary air to increase by a certain amount from the reference value.

This makes it possible to prevent a decrease in the weight flow rate due to a decrease in air density by increasing the volumetric flow rate. but.

This method, in which changes in atmospheric pressure are simply controlled by a diaphragm type flow control valve 11 that receives a constant negative pressure, has the disadvantage that the accuracy of the flow rate of the secondary air is low due to variations in the secondary air pump itself.

SUMMARY OF THE INVENTION An object of the present invention is to provide a burner air control device for a diesel particulate filter that can accurately control the flow rate of secondary air.

The diesel particulate filter burner air control device according to the present invention includes an exhaust bypass passage that bypasses the filter and an air supply passage to the burner.

A flow control valve that changes the flow area of the air supply path.

This configuration includes a relief valve that moves to keep the differential pressure across the flow control valve constant, and a control section that operates the amount of opening and closing of the flow control valve.

The present invention will be described below with reference to the accompanying drawings.

FIG. 5 shows a burner air control device (hereinafter simply referred to as burner air control device) for a diesel particulate filter as an embodiment of the present invention.

This burner air control device includes the same members as the conventional device shown in FIG. 4, and the same members will be given the same reference numerals to avoid confusion hereafter, and their repeated explanation will be omitted. Exhaust path 3
A burner 20 supplies hot air at a predetermined high temperature and a predetermined excess air ratio to the filter 5 through a secondary air flow path (hereinafter simply referred to as a secondary flow path) 21 and a secondary air pump (hereinafter simply referred to as a secondary pump). ) Receives secondary air from 9. The secondary pump 9 causes air to flow into the secondary flow path 21 via the air filter 22, and the flow rate 21 that increases or decreases the flow area of this secondary flow path is large between the air filter 22 and the secondary pump 9. Temperature sensor 2
5, and a pressure sensor 26 for detecting the pressure is provided upstream of the flow control valve 28.

The valve driving device 23 integrally connects the flow rate control valve 28 with a diaphragm 29, and the diaphragm has an atmosphere opening chamber 60.
and a negative pressure chamber 61 provided with a compression spring 47 are opposed to each other.

The valve body flow rate control valve 28 is attached to the secondary air flow path 21 so as to vary the flow path area S thereof. The negative pressure chamber 31 is a duty solenoid valve (hereinafter simply referred to as a duty valve).
It is connected via 32 to the vacuum pump 12, which is a negative pressure source.

The duty valve 32 is turned on and off at a frequency of 10 Hz to 20 Hz to control switching between communicating the negative pressure chamber 31 with the vacuum pump 12 or guiding the atmosphere to the negative chamber 31,
The width of the pulse 0 to 1, which is the time width of the ON time of the valve body, is variably controlled by the output signal of the combustion control device 27, thereby changing the negative pressure value of the negative pressure chamber 61. Note that the flow control valve 2B is displaced from the fully open position to the fully closed position, and the amount of this displacement is variable.The secondary flow path 21 between the electrical resistance flow control valve 28 and the secondary pump 9 is filled with air. A relief valve 34 is installed to release the water to the atmosphere. A diaphragm 36 integral with the valve body 65 of this relief valve faces the atmosphere open chamber 37 and the negative pressure chamber 38. The negative pressure chamber 58 is connected to a negative pressure pump 12, which is a negative pressure source, via a flow rate regulating throttle 39, and a negative pressure regulating valve 40 is connected to a negative pressure regulating path a between this throttle 39 and the negative pressure chamber 38. .

The negative pressure regulating valve 40 has a front chamber 41 that receives static pressure on the inflow side of the flow control valve 23 and a rear chamber 42 that receives static pressure on the outflow side, and one compartment is divided by a diaphragm 46. The rear chamber is equipped with a compression spring 45 and is also fitted with a pipe 44 whose opening 48 can be closed by the diaphragm 45 acting as a valve body.

The outer end of this pipe is connected to the negative pressure adjustment path a side described above. Therefore, when the closing force applied to the diaphragm 4 due to the differential pressure across the flow rate control valve 28 exceeds the opening force of the compression spring 45, the opening 48 of the pipe 44 is closed, and when the pressure becomes lower than the opening force, the opening 48 is opened. When the opening 48 of the pipe 44 is opened, the throttle 69 works, and air from the rear chamber 42 side flows into the negative pressure adjustment path a to loosen the amount of pressure reduction in the negative pressure chamber filter 8, and the valve moves in the valve closing direction C. The body 35 moves. Conversely, when the pipe 44 is closed, only the negative pressure from the vacuum pop 12 is applied to the negative pressure adjustment path a, and the valve element 35 moves in the valve opening direction P.

The main part of the combustion control device 27 is formed by a microcomputer. The combustion control device 27 receives output signals from the upstream pressure sensor 26 of the flow rate control valve 2, the atmospheric temperature 7->25, the position control valve 3, and the burner exhaust gas temperature sensor 46, and controls the flow rate. The volumetric flow rate of the secondary air is increased or decreased by an appropriate amount according to the upstream pressure of the valve and the increase or decrease in the atmospheric temperature, and the burner exhaust gas is increased or decreased by an appropriate amount. T ■ However, S: Channel cross-sectional area.

÷ , 4I7': Differential pressure before and after the flow control valve 28.

! =Flow rate control valve 28'i is given by the air density on the downstream side.1 In this embodiment, AP is always kept constant and C is the flow rate coefficient and takes an approximately constant value, so the flow path cross-sectional area is determined by the change in air density. By correcting this amount, the weight flow rate of the secondary air can be made constant.

Furthermore, formula 0 is of first order, considering the air y11'A degree and pressure,
transformed into a sea urchin.

S-etc.76 layer 1-stack σ however T'ura (meter control valve upstream air temperature.

P: Be (, air pressure on the upstream side of the quantity control valve.

K: Constant of proportionality, that is, the weight flow rate is made constant by increasing the cross-sectional area of the flow path for air temperature Y1, and decreasing the cross-sectional area of the flow path for Y1 of air pressure. I can do it. Note that the cross-sectional area of the flow path has a one-to-one correspondence with the flow rate control valve lift 1 and loss, so by indicating the required lift rule for T and P using a map or the like, the 9 weight flow rate can be kept constant.

Here, P is the air pressure on the upstream side of the flow rate control valve 28, but +t
1F, the pressure in the flow path near the loss control valve 28 is sufficient, and can also be the air pressure on the downstream side of the flow rate control valve 28.

,+ta. As shown in FIG. 6, the reference value T is set so that the burner exhaust gas temperature is constant. Compare with and set reference value111
1. While the amount is below at or above, the standard fuel amount q.

, conversely], (The fuel injection amount q is controlled by the combustion control device 27 so that a small fuel amount q2 is injected while the quasi-value exceeds the set value 4 or more.

The operation of the burner air control device shown in FIG. 5 will be explained.

The combustion control device 27 detects the exhaust pressure on the upstream side of the filter 5 using the pressure detection device 19, and when the exhaust pressure exceeds a set value, the combustion control device 27 enters a re-combustion process. First, the combustion control device 27 issues a signal to turn on each of the primary and secondary air pumps 7.9, the fuel pump 8, and the ignition coil 6. At the same time, based on the output signal of the burner exhaust gas temperature sensor 46, this is the standard 411 degrees T. The lower the q fuel flow value. An output signal is given to the fuel regulating valve 17 so that the amount of fuel is adjusted to ql, and vice versa, to q2. Incidentally, the negative pressure regulating valve 40 detects the differential pressure across the flow rate control valve 28 and controls the relief valve 34 so as to always maintain the secondary flow path 21 at the differential pressure value set in the compression spring 45. That is, when the differential pressure around 9 increases, the pipe 44 is closed and all the negative pressure of the vacuum pump 12 is added to the negative pressure chamber 38, and the valve body 65 is relatively thick (moved) in the valve opening direction P, and the secondary flow path 21 air is released into the atmosphere, and conversely, when the differential pressure decreases, the pipe 44
opening 4B opens, air flows into the negative pressure adjustment path a from the rear chamber 42 side, only relatively weak negative pressure is applied to the negative pressure chamber 38, and the relief valve 35 moves in the valve closing direction C. .

The release of air from the secondary flow path 21 is suppressed. like this,
The differential pressure across the flow rate control valve 28 is maintained constant only by so-called pneumatic operation.

On the other hand, negative pressure is applied to the negative pressure chamber 61 of the valve drive device 23 via the duty valve filter 2 . in this case.

The combustion control device 27 uses a map in which the lift position of the flow control valve 28 that can obtain a predetermined weight flow rate Ga is recorded in advance based on the upstream pressure of the flow control valve 28 and the atmospheric crystallinity. I ask. Then, the combustion control device 27 controls the duty valve '
52, feedback control is performed by varying the duty ratio. In addition.

Each of the above maps is input in advance by setting the proportionality constant etc. through experiments based on the theoretical formulas mentioned above (this allows the secondary air to Adjusted so that the weight flow rate is always constant.

] is supplied to the case 20.

From the above, the non-air control device shown in FIG. The differential pressure across the valve 28 is always kept constant by a pneumatic relief valve driving device 34, etc., and the flow path area S is set by the control unit 27 in order to cancel fluctuations in the pressure on the upstream side of the flow rate control valve 28 and the atmospheric temperature. To correct the value,
By controlling the operation of the duty valve 32, the flow rate of the secondary air can be controlled with high accuracy.
7 has the effect that it is not necessary to control variations in the discharge amount of the secondary pump 9 itself, and that it can be segmented.

The air control device shown in FIG. 5 is the secondary flow path 210
The differential pressure between the front and rear is detected by the negative pressure regulating valve 40, and the negative pressure value of the negative pressure regulating path a is corrected according to this detected value, and the relief valve driving device 34 is operated. As shown in FIG. 7, the relief valve drive device 50 that releases the air in the secondary flow path 21 to the atmosphere may be actuated by the differential pressure between the upstream and downstream sides of the direct flow control valve 28. In this case, the relief valve 51 is A rear chamber 56 equipped with a compression spring 52 that presses in the valve closing direction C, and a front chamber 54 that receives pressure between the flow rate control valve 28 and the secondary pump 9 apply air pressure to the diaphragm 55. That is, a difference of around 1 When the pressing force due to pressure exceeds the pressing force of the compression spring 52, the relief valve 5
1 operates in the valve opening direction P.

On the other hand, when the temperature drops below the limit, the relief valve 51 operates in the valve closing direction C. As a result, variations in the discharge air of the secondary pump 9 are eliminated, and stable air reaches the flow rate control valve 28. This device has the advantage that the negative pressure regulating valve 40 shown in the previous embodiment (FIG. 5) can be removed. However, the compression spring 52
It is necessary to apply a pressing force in the valve closing direction C against the pressing force of the front chamber 54 which directly receives the secondary F, and it is necessary to increase the spring constant.

The burner air control device shown in FIG. 5 connects the valve drive device 26 to the combustion control device 27. Upstream pressure sensor 26 of flow control valve 28. Although the atmospheric temperature sensor 25 was used for operation, instead of this, the flow rate control valve 61 may be controlled only at atmospheric pressure, as shown in FIG.

It is sandwiched between a constant pressure chamber 65 equipped with a compression spring 64.

The constant pressure chamber 65 is connected to a constant pressure source 66 that generates a constant pressure with respect to absolute pressure.

The constant pressure source 66 has a configuration shown in FIG. 9, for example,
A constant pressure chamber 301 sealed by a housing 300, a vacuum diaphragm 302 provided within the constant pressure chamber 301. A negative pressure pipe 50 which communicates the vacuum pump 12 with the constant pressure chamber 3'01 and is provided with a constriction part 306a in the middle, has one end open to the atmosphere and has a spring spring 0 as shown in FIG.
4 and an atmosphere open tube 606 into which the sphere 605 is incorporated. and a communication pipe 307 that supplies constant pressure.

When the pressure in the constant pressure chamber 301 decreases, the vacuum diaphragm 302 expands and presses the sphere 305 in the atmosphere opening tube 306, causing the atmosphere to flow into the constant pressure chamber 301 through the opening tube 306. When the atmosphere flows into the constant pressure chamber 301, the pressure inside the constant pressure chamber 301 rises and the vacuum diaphragm filter 02 contracts, causing the spherical filter 05 to open to the atmosphere pipe 3.
06 will be closed. By repeating these steps, the pressure in the constant pressure chamber becomes approximately constant.

(when reaching the point), the flow rate control valve 61 moves in the valve opening direction P.

The flow path area S is increased to increase the volumetric flow rate. Conversely, when atmospheric pressure rises, the flow control valve 61 moves in the closing direction C,
The flow path area S is narrowed to lower the 1 volume flow rate. By such an operation, the weight flow rate of the secondary air can be maintained substantially constant. In this case, the control section is simplified and there is an effect of reducing the number of parts by one.

FIG. 10 shows a burner air control device in which the relief valve drive device 50 explained in FIG. 7 and the flow rate control device 60 explained in FIG. 8 are attached to the secondary flow path 21. In this embodiment, all the valves are controlled by pneumatic operation, and the effect of reducing the number of parts is that an aneroid valve 100 whose inside is vacuum-sealed is used instead of the flow control device 23.60 to directly control the flow rate. Flow control device 1 that opens and closes 28
It may be set to 02.

To explain based on FIG. ξ, the flow rate control device 102 is
A bellows 100 whose interior is vacuum-sealed and a bellows 1
00 and a spring 10 provided in the bead.
The bellows 100 and the flow rate control valve 2B are connected to each other.

According to the above configuration, when the atmospheric pressure becomes low, the bellows 100
expands due to the balance between the surrounding atmospheric pressure and the biasing force of the spring 105, and the flow rate control valve 28 is lowered to widen the flow path area S. Further, when the atmospheric pressure increases, the bellows 100 contracts, and the flow rate control valve 28 narrows the upward flow area S.

Therefore, according to the configuration of this embodiment, the flow area S can be controlled in accordance with the atmospheric pressure with an extremely simple configuration.

Incidentally, since the flow rate control device shown in FIG. 12 is the same as that shown in FIG. 11, the explanation will be omitted by referring to the same number.

Up A certain engine speed, load, etc. may be applied.

[Brief explanation of drawings]

Fig. 1 is a discharge pressure-volume flow diagram of a positive displacement air pump, Fig. 2 is a diagram illustrating changes in weight flow rate due to elevation differences, and Fig. 6 is a diagram explaining variations in weight flow rate of the air pump itself. Figure 4 is a schematic diagram of the conventional air control device, Figures 5, 7, 8, and 10.
11 and 12 are schematic configuration diagrams of burner air control devices as different embodiments of the present invention, FIG. 6 is an exhaust gas temperature-fuel quantity characteristic diagram, and FIG. 9 is a constant pressure 3A and 3B each illustrate a cross-sectional view of one embodiment of a source; 3...Exhaust path, 5...Filter. 9... Secondary pump, 20... Burner. 21...Secondary flow path, 23...Flow rate control device. 27... Combustion control device, 28... Flow rate control valve. 34... Relief valve, 40... Negative pressure regulating valve. 66... Constant pressure source, a... Negative pressure adjustment path. 102...Beps, 202...Exhaust bypass path Fig. 1 q Tsuchiyama/E (mmH) Fig. 2 Fig. 3 01 appeared [m-n) 113

Claims (1)

[Claims] 1. A particulate filter provided in the exhaust path of a diesel engine to collect particulates in exhaust gas, an exhaust bypass path bypassing the particulate filter, and provided upstream of the particulate filter. and a burner device to which fuel and air are supplied, the exhaust gas is passed through the exhaust bypass passage in a state in which more than a set amount of particulates are collected in the particulate filter, and the particulates are combusted by the burner. In the filter regeneration device, a supply path for supplying air to the burner device via an air supply device, a flow rate control valve provided in the supply path for variably controlling the flow path area of the supply path, and a a flow control device that drives the flow rate control valve according to at least one of the temperature or pressure of the air; a relief valve that is provided in the supply path and releases a part of the air in the supply path to the outside; a relief valve control device that controls opening and closing of the relief valve in response to a pressure difference between the upstream side and the downstream side of the flow rate control valve in the supply path; and a relief valve control device that controls the opening and closing of the relief valve in response to a pressure difference between the upstream side and the downstream side of the flow rate control valve in the supply path, and a relief valve control device that detects regeneration timing of the filter and directs the exhaust gas to the exhaust bypass. A regeneration device 2 for a diesel particulate filter is characterized in that it is equipped with a combustion control device for causing the burner device to operate the burner device while the flow rate is flowing through the flow rate control device. It consists of a pressure responsive device consisting of a constant pressure chamber into which a constant pressure is introduced, a diaphragm that separates both chambers and is connected to the flow control valve, and a spring that applies a biasing force to the diaphragm. The diesel particulate filter regeneration device 3 according to claim 1, characterized in that the opening degree of the flow rate control valve is increased, and the flow rate control device is connected to the flow rate control valve. A pressure-responsive device comprising a bellows and a casing surrounding the bellows and having an opening to the atmosphere, the bellows expanding when the atmospheric pressure decreases and the opening degree of the flow rate control valve increasing. In the diesel particulate filter regeneration device 4 according to item 1, the relief valve control device is connected to a first chamber to which the downstream pressure of the flow rate control valve of the supply path is introduced, and the upstream pressure of the flow rate control valve. a second chamber into which is guided, a diaphragm that separates the first and second chambers and is connected to the relief valve so as to operate in conjunction with the relief valve, and a spring that applies a biasing force to the diaphragm, Claims characterized in that the relief valve is configured to open when the pressure on the upstream side of the flow control valve exceeds a set value compared to the pressure on the downstream side of the flow control valve. In the diesel particulate filter regeneration device 5 according to item 1, the relief valve control device is connected to a first chamber to which the downstream pressure of the flow rate control valve of the supply path is introduced, and a first chamber to which the downstream pressure of the flow rate control valve of the supply path is guided. A negative pressure regulating valve, a negative pressure source, and a first passage, comprising a second chamber to be guided, a first diaphragm that separates the first chamber and the second chamber, and a first spring that applies a biasing force to the first diaphragm. a negative pressure chamber communicated with the atmospheric pressure chamber, an atmospheric pressure chamber opened to atmospheric pressure, and a second diaphragm that separates the negative pressure chamber and the atmospheric pressure chamber and is connected to the relief valve;
a relief valve drive device comprising a second spring that applies a biasing force to the second diaphragm; one end is provided with an opening facing the first diaphragm; the other end is connected to the negative pressure source and the relief valve drive device; A second passageway connected to the first passageway connecting the
When the pressure on the upstream side of the flow control valve becomes greater than the set value compared to the pressure on the downstream side of the flow control valve,
The diesel engine according to claim 1, wherein the opening of the second passage is closed by the first diaphragm, the negative pressure in the negative pressure chamber is increased, and the relief valve is opened. A particulate filter regeneration device 6, a particulate filter provided in the exhaust path of the diesel engine to collect particulates in exhaust gas, an exhaust bypass path bypassing the particulate filter, and provided on the upstream side of the particulate filter. and a burner device to which fuel and air are supplied, the exhaust gas is passed through the exhaust bypass passage in a state in which more than a set amount of particulates are collected in the particulate filter, and the particulates are combusted by the burner. In the filter regeneration device, the control device detects the regeneration timing of the filter and causes the exhaust gas to flow through the exhaust bypass path and causes the filter regeneration device including the burner device to perform combustion operation, and a supply supply that supplies air to the burner device. a flow rate control valve provided in the supply path to variably control the flow path area of the supply path, a pressure detection means provided in the vicinity of the flow rate control valve in the supply path, and an air temperature in the supply path. temperature detection means for detecting the temperature, a calculation section provided in the control device for calculating the optimum lift amount of the flow control valve based on the pressure and temperature, and a calculation section connected to the flow control valve to calculate the lift amount calculated by the calculation section. a flow control device comprising a valve driving device that drives a flow rate control valve based on the flow rate control valve; a relief valve provided in the supply path and discharging a part of the air in the supply path to the outside; and the flow control device in the supply path. A diesel particulate filter regeneration device 7 characterized in that it is equipped with a relief valve control device that controls opening and closing of the relief valve in response to a pressure difference between the upstream side and the downstream side of the valve, wherein the valve drive device is a negative pressure chamber communicating with a pressure source;
an atmospheric pressure chamber opened to the atmosphere, a diaphragm that separates the atmospheric pressure chamber and the negative pressure chamber and is connected to the flow control valve so as to operate in conjunction with the flow control valve, and a biasing force is applied to the diaphragm. and a switching valve provided between the negative pressure chamber and the negative pressure source to open the negative pressure chamber to the atmosphere or to communicate the negative pressure chamber with the negative pressure source, The diesel particulate filter regeneration device 8 according to claim 6, characterized in that the flow rate control valve is set to a target value by controlling the switching valve based on the calculated value. The diesel particulate filter regeneration device 9 according to claim 7, wherein the valve is duty-controlled by a signal from the calculation section to set the valve lift amount of the flow rate control valve to a target value. The diesel particulate filter regeneration device according to claim 7, wherein the switching valve is controlled on and off by a signal from the calculation section to set the valve lift amount of the flow rate control valve to a target value. 10. It has a lift position detector that detects the valve lift position of the flow control valve, and inputs the value detected by the lift position detector to the calculation section, and controls the valve lift amount of the flow control valve by feedback control. The diesel particulate filter regeneration device 11 according to claim 7 is characterized in that the pressure is set to a target value, and the relief valve control device is configured to set the pressure to the downstream side of the flow rate control valve in the supply path. a second chamber to which the upstream pressure of the flow rate control valve is guided; a diaphragm that separates the first and second chambers and is connected to the relief valve so as to be interlocked with the relief valve; The relief valve is configured to open when the pressure on the upstream side of the flow control valve exceeds a set value compared to the pressure on the downstream side of the flow control valve. The diesel particulate filter regeneration device 12 according to claim 7 is configured such that the relief valve control device is connected to a first valve to which pressure on the downstream side of the flow rate control valve in the supply path is guided. a second chamber to which the upstream pressure of the flow rate control valve is guided, a first diaphragm that separates the first chamber and the second chamber, and a first spring that applies a biasing force to the first diaphragm. A negative pressure regulating valve, a negative pressure chamber communicated with a negative pressure source through a first passage, an atmospheric pressure chamber opened to atmospheric pressure, separating the negative pressure chamber and the atmospheric pressure chamber, and connecting to the relief valve. a second diaphragm;
a relief valve drive device comprising a second spring that applies a biasing force to the second diaphragm; one end is provided with an opening facing the first diaphragm; the other end connects the negative pressure source and the relief valve drive device; and a second passage communicating with the first passage, and when the pressure on the upstream side of the flow control valve becomes greater than the set value compared to the pressure on the downstream side, the first diaphragm The diesel particulate filter regeneration device according to claim 7, characterized in that the opening of the passage is closed, the negative pressure in the negative pressure chamber rises, and the relief valve opens.