WO2004031548A1

WO2004031548A1 - Pm continuous regeneration device for diesel engine, and method of producing the same

Info

Publication number: WO2004031548A1
Application number: PCT/JP2003/012476
Authority: WO
Inventors: Shigeru Yamamori
Original assignee: Tokudaiji Institute Of Automotive Culture Inc.; Depro Corporation
Priority date: 2002-10-01
Filing date: 2003-09-30
Publication date: 2004-04-15
Also published as: AU2003266704A1; JP2006097469A; AU2003266704A8

Abstract

In conventional automobile diesel engines, efforts have been made to reduce harmful substances contained in exhaust gases mainly by improving combustion in the engine itself; however, it has been very difficult to satisfy the exhaust restrictions in force on and after 2005. Accordingly, the invention provides a PM oxidation method for oxidizing particulate matter contained in exhaust gases discharged from a diesel engine (10) by passing the exhaust gases through an exhaust cleaning device, the method being characterized by providing an intake throttle (24) in the intake passageway of the diesel engine (10) to increase the temperature of the exhaust gases flowing from the diesel engine (10) into the exhaust cleaning device, and periodically opening the intake throttle (24) to supply fresh gas to the diesel engine (10). According to the invention, it becomes possible to significantly increase the NO and residual oxygen in the exhaust gases flowing into a μDPF (30) or the like and to effectively oxidize the particulate matter during a low load on the diesel engine and also during idling.

Description

Specification

PM continuous regeneration apparatus for diesel engine and method thereof

The present invention relates to a method of activating a catalyst used for the purpose of reducing pollutants from a diesel engine (hereinafter referred to as “DE”). Relates to a PM oxidation method capable of effectively oxidizing (hereinafter referred to as “PM”). Background art

The yearly stricter DE emission limit values will be PM and hydrocarbon (HC) and carbon dioxide (CO) oxidized by carbon dioxide (CO ₂ ) and water (H ₂ 0), NOx must be dissociated into nitrogen (N ₂ ) and oxygen (0 ₂ ) to be rendered harmless and then discharged.

In the past, DE for vehicles has been trying to reduce harmful substances contained in the exhaust gas mainly by combustion improvement of the engine itself, but it is very difficult to meet the emission control values after 2005. It is considered.

Therefore, recently, a continuously regenerating DPF (Continuously Regenerative) composed of a diesel oxidation catalyst for the former stage ("D oc" in the present invention) and a diesel particulate 'filter (for the present invention "DPF") Research and development on the Diesel Particulate Filter is underway. In front of the DO C HC is variable I spoon into C0 ₂ and H ₂ 0, CO changes to C0 _2. Furthermore, nitrogen monoxide (NO) in NO x is changed to nitrogen dioxide (N 0 ₂ ). In N0 ₂ generated in the previous stage in a subsequent stage of the DPF by burning the soot component in PM, discharged as C0 _2. This continuously regenerating DPF is known as a CRT invented by Johnson Matthey. In addition, various structures on the DPF, which have only a filter function Research and development of integrated DPF (catalyst-supported DPF) with supported oxidation catalyst is also in progress. In the present invention, the DPF having only the filter function is simply referred to as the DPF, and the DPF supporting the catalyst is referred to as the DPF supporting the catalyst. Further, in the present invention, the continuously regenerating DPF includes a catalyst supporting DPF, a combination of DOC and DPF, and a combination of DOC and catalyst supporting DPF.

Stage continuous regeneration type DPF to provide a DeNOX catalyst, research and development has been advanced with regard selective catalytic reduction method also dissociates the last remaining NO _X (S CR). The combination of the SCR and the CRT is known as Johnson Matthey's S-CRT.

The combustion of PM in the above continuous regeneration type DPF is said to be 350 ° C. or higher for the catalyst supported type DPF, and 250 ° C. to 450 ° C. for the DOC. The exhaust temperature at the idle time of a normal DE is 70 ° C to 100 ° C, and at a traveling speed of 80 km / hr or less of a vehicle driven by DE, the DE load corresponding to the traveling resistance generated The degree of exhaust does not reach 260 ° C (250 ° C + α), and soot collected in the continuous regenerative DPF accumulates in the filter without being oxidized, and the filter is clogged. There was a problem that it became impossible to drive soon.

In order to solve the above problems by setting the exhaust gas temperature at the inlet of the continuous regeneration type DPF at idle time and low load to more than 260 ° C., in Patent Document 1, the reason is that the exhaust temperature at normal idle idle is low. Is focused on the fact that the excess air ratio (hereinafter referred to as “E”) is as high as 10 to 12 and there is a means to reduce the amount of air in the cylinder of the DE and bring λ closer to 1 . Specifically: a) Intake throttle

As with a gasoline engine, install a throttle valve in the intake system and throttle the intake air amount to make λ as close as possible to 1 and raise the exhaust temperature.

b) Exhaust two-stage cam (hereinafter "ESC")

When the intake stroke is performed while squeezing the intake to obtain the effect of the above-described intake throttle The exhaust valve is opened by the ESC near the bottom dead center of the intake stroke, and the high temperature exhaust gas is backflowed into the decompressed cylinder to adiabatically compress the mixed gas whose temperature has become high, and the exhaust gas temperature Raise.

This is a kind of exhaust gas recirculation (EGR), and the high temperature exhaust mixes with the air in the cylinder to further raise the air temperature just before the compression stroke and promote combustion of the injected fuel near the top dead center. It is considered that the high temperature EGR contains radicals promoting combustion immediately after being discharged, and the effect of the radicals does not disappear until the top dead center of the compression stroke is reached.

c) Reduced cylinder

By reducing the number of six-cylinder engines to three, etc., the amount of fuel supplied per cylinder increases, so the exhaust temperature rises.

d) Exhaust throttle

By installing a throttling valve in the exhaust system of a diesel engine and throttling the throttling valve, the back pressure increases, the pressure difference between the inside and outside of the cylinder increases, and the amount of high temperature EGR gas recirculating into the cylinder increases. As a result, the in-cylinder gas temperature at the beginning of compression rises, so the compression end temperature also rises, and even with the same fuel injection amount, the exhaust gas temperature becomes higher than before throttling the exhaust throttle valve. As a result, white smoke emissions are reduced, and the high exhaust gas temperature also raises the D P F inlet temperature, which is effective in PM oxidation.

The means a) to d) are combined.

In addition to the main catalyst, Japanese Patent Application No. 20 0 1-1 2 9 8 3 3 has an auxiliary catalyst with a small heat capacity installed close to the engine, and uses the main catalyst at high output of the engine and auxiliary catalyst at low output. In order to avoid cooling due to long piping and to avoid a decrease in specific power of the engine due to the catalyst being placed close to the engine, an auxiliary catalyst with a small heat capacity at engine start is used. By using the catalyst, it is possible to raise the temperature in a short time to activate the catalyst.

Furthermore, in Japanese Patent Application No. 200 2-0 94 1 74, in addition to the main catalyst, an auxiliary catalyst with a small heat capacity is provided, and intake throttling, ESC, cylinder reduction and exhaust throttling are performed. To make it possible to

Japanese Patent Application Laid-Open No. 200 1-36 440, Japanese Patent Application No. 2 00 1 2 98 3 3 and Japanese Patent Application No. 20 0 2 0 0 4 1 74 Maintaining low exhaust temperature and high exhaust temperature of DE In the equipment, under adverse conditions such as a low load condition for a long time, the amount of PM accumulated inside the catalyst continues to exceed the regeneration capacity of the catalyst, resulting in the problem that the engine eventually misfires. .

In particular, for a 3.0 liter supercharged engine, the low load and high exhaust temperature maintenance device of DE described in Patent Document 1 succeeded in effective exhaust gas rise and PM oxidation, but an engine with disadvantageous conditions. However, PM oxidation could not be performed reliably. The test results will be described later.

Therefore, in view of the above-mentioned conventional situation, it is an object of the present invention to provide a PM oxidation method capable of oxidizing PM even if a condition disadvantageous to PM oxidation such as at low load and idling is continued for a long time. Do. Disclosure of the invention

In order to solve the above problems, the PM oxidation method in diesel engine according to the present invention is a PM oxidation method in which exhaust gas discharged from a diesel engine is oxidized through PM (particulate matter) in exhaust gas through an exhaust gas purification device. An intake throttle valve is provided in the intake passage of the diesel engine to increase the exhaust temperature of the exhaust gas flowing from the diesel engine into the exhaust gas purification apparatus, and the intake throttle valve is periodically opened. It is characterized by supplying fresh air to a diesel engine.

In the above PM continuous regeneration method, the exhaust valve is opened near the bottom dead center of the intake stroke of the DE to raise the exhaust temperature of the exhaust gas flowing from the DE (diesel engine) into the exhaust purification device. The exhaust gas may be backflowed into the cylinder of the DE where the exhaust gas is depressurized to perform exhaust gas recirculation. That is, the above ESC can be used to raise the exhaust gas temperature.

The above-mentioned exhaust purification system includes DOC and DPF, DOC and DPF with catalyst. It can be any one continuous regeneration DPF selected from catalyst-loaded DPFs.

Also, in the above PM continuous regeneration method, the exhaust gas purification apparatus is composed of mD PF (main exhaust gas purification apparatus) and t DPF (auxiliary exhaust gas purification apparatus), and the exhaust port of DE and mDP F are in the main exhaust pipe. The auxiliary exhaust pipe is connected with both ends connected to the main exhaust pipe, and the auxiliary exhaust pipe is connected with μ DP F. When the small exhaust flow rate at low load of DE, the main exhaust is connected. By closing the switching valve provided on the pipe, the total flow rate of exhaust gas from the DE is sent to the μ DPF through the auxiliary exhaust pipe, and switching is performed when the flow rate of exhaust gas increases at high load of DE. The valve may be opened. As shown in Japanese Patent Application Nos. 200 1-2 8 8 3 3 3 and Japanese Patent Application Nos. 200 2-0 9 14 1 4 4, the auxiliary catalyst with a small heat capacity is placed close to the engine in addition to the main catalyst. It is a method.

This mD PF (main DPF) can be any one of continuous regeneration DP F selected from DOC and DP F, DOC and catalyst supported DPF, and catalyst supported DPF, and ^ DP F (micro DP F) can be any one continuous regeneration DPF selected from DOC and DPF, DOC and catalyst-supported DP F, and catalyst-supported DP F.

In the PM continuous regeneration method of the present invention, DE can be multi-cylinder, and cylinder reduction operation can be performed in a multi-cylinder DE.

Further, in order to solve the above problems, the PM oxidizer in the diesel engine according to the present invention oxidizes particulate matter (PM) contained in the exhaust of the diesel engine deposited in the diesel particulate filter. In a PM oxidizer of a diesel engine for purifying exhaust gas, an intake flow control valve for adjusting an intake flow rate of the diesel engine, a first timer for measuring an elapse of a first predetermined time, and a second predetermined time A second timer for measuring the elapsed time, and a control finger 4 for increasing the intake flow rate to the intake flow control valve after the first predetermined time measured by the first timer has elapsed, and the second timer Measured second predetermined time The control apparatus may further comprise: control means for outputting a control command for returning the intake flow rate to the original intake flow rate to the intake flow rate adjustment valve after a lapse of time.

In order to solve the above problems, the PM oxidizer of the diesel engine according to the present invention opens the exhaust pulp near the end of the intake stroke of the engine and returns the exhaust to the cylinder before combustion. An exhaust cam, an intake flow control valve for adjusting an intake flow rate of a diesel engine, a first timer for measuring an elapsed time of a first predetermined time, and a second timer for measuring an elapsed time of a second predetermined time After the first predetermined time measured by the first timer has elapsed, a control command to increase the intake flow rate is output to the intake flow control valve, and after the second predetermined time measured by the second timer has elapsed. And control means for outputting a control command for returning the intake flow rate to the original intake flow rate to the intake flow rate adjustment valve.

Further, in order to solve the above problems, the PM oxidizer in the diesel engine according to the present invention is two types of DPFs that capture and treat particulate matter contained in exhaust gas of a diesel engine, and the diesel engine Switching valve that switches the flow path of the exhaust to the main DPF that processes a large amount of exhaust discharged when the load is high, and the micro DPF that processes a small amount of exhaust discharged when the diesel engine has a low load; An intake flow control valve for adjusting the intake flow rate of the first timer, a first timer for measuring the lapse of a first predetermined time, and a second timer for measuring the lapse of a second predetermined time; The control command for the switching valve and the intake flow control valve is output according to the amount and engine speed, and after the first predetermined time measured by the first timer has elapsed. The control command to increase the intake flow rate is output to the intake flow rate control valve, and the control command to return the intake flow rate to the original intake flow rate is sent to the intake flow rate control valve after the second predetermined time measured by the second timer. And a control means for outputting. Further, in order to solve the above problems, the PM oxidizer in the diesel engine according to the present invention comprises an EGR means for controlling the amount of exhaust recirculation when recirculating the exhaust to the intake side, and an intake flow rate of the diesel engine. Intake to adjust the A flow control valve, a first timer for measuring the lapse of a first predetermined time, a second timer for measuring the lapse of a second predetermined time, and a first predetermined time measured by the first timer After a lapse of time, a control command to increase the intake flow rate is outputted to the intake flow rate control valve, and after the second predetermined time measured by the second timer elapses, the intake flow rate is returned to the original intake flow rate to the intake flow rate control valve. And control means for outputting a control command.

Further, in order to solve the above problems, the PM oxidizer in the diesel engine according to the present invention comprises an intake flow control valve for adjusting an intake flow rate of the diesel engine, and a first for measuring an elapsed time of a first predetermined time. A timer, a second timer that measures the passage of a second predetermined time, a differential pressure sensor that detects a pressure difference before and after the DPF, and a first predetermined time measured by the first timer. If the pressure difference detected by the differential pressure sensor is greater than or equal to a predetermined threshold value, a control command to increase the intake flow rate is output to the intake flow rate control valve, and the second timer measures the second The control means is provided with a control means for outputting a control command for returning the intake flow rate to the original intake flow rate to the intake flow rate adjustment valve after a predetermined time has elapsed.

Further, in order to solve the above problems, the PM oxidizer in the diesel engine according to the present invention opens the exhaust valve near the end of the intake stroke of the engine and returns the exhaust to the cylinder before combustion. An exhaust cam, an intake flow control valve for adjusting an intake flow rate of a diesel engine, a first timer for measuring an elapsed time of a first predetermined time, and a second timer for measuring an elapsed time of a second predetermined time And a differential pressure sensor for detecting a pressure difference before and after the DPF, and after a lapse of a first predetermined time measured by the first timer, the pressure difference detected by the differential pressure sensor being equal to or greater than a predetermined threshold. In some cases, a control command to increase the intake flow rate is output to the intake flow rate control valve, and the intake flow rate is output to the intake flow rate control valve after a second predetermined time measured by the second timer. Characterized by comprising a control means for outputting a control command for returning the amount.

Further, in order to solve the above-mentioned problems, it is preferable to The PM oxidation device measures the lapse of a third predetermined time in addition to a first timer that measures the lapse of a first predetermined time and a second timer that measures the lapse of a second predetermined time. And a fourth timer for measuring the lapse of a fourth predetermined time, and after the lapse of the first predetermined time measured by the first timer, the differential pressure sensor When the detected pressure difference is equal to or greater than a predetermined threshold value, and before the elapse of a third predetermined time measured by the third timer before the second predetermined time measured by the second timer, the intake flow control valve Control means for outputting a control command for increasing the intake flow rate, and outputting a control command for returning the intake flow rate to the original intake flow rate to the intake flow control valve after the fourth predetermined time measured by the fourth timer. It is characterized by Brief description of the drawings

Fig. 1 is a schematic view of a cylinder of DE used in the PM oxidation method of the present invention, wherein (a) shows the vicinity of the bottom dead center before the piston bottom dead center, and (b) shows the bottom death of the piston. It is a figure which shows the vicinity of the bottom dead center after point.

FIG. 2 shows an embodiment of the PM oxidation method of the present invention in which the auxiliary exhaust gas purification device (^ D P F) is used.

Fig. 3 is a schematic view of the auxiliary exhaust purification device (DPF).

FIG. 4 shows a graph of the test results in Test 1 and shows the case where "fresh air spike" was not performed.

FIG. 5 shows a graph of the test results in Test 2 and shows the case where “fresh air spike” is performed.

FIG. 6 shows a graph of the test results in Test 3 and shows the results of testing at various “new air spike” timings.

FIG. 7 is a diagram showing an overall configuration of an exhaust gas purification apparatus for a diesel engine according to the present invention.

FIG. 8 is a cross-sectional view of a combustion chamber portion of a diesel engine equipped with an internal EGR mechanism that returns the exhaust gas directly to the cylinder before combustion. FIG. 9 is a diagram showing the relationship between the position of biston and the lift amount of the intake valve and the lift amount of the exhaust valve.

FIG. 10 is a diagram showing an I T P control map used for an exhaust gas purification apparatus of a diesel engine according to the present invention.

FIG. 11 is a signal processing block diagram of control means according to the present invention.

FIG. 12 is a timing chart showing the new air spike method according to the present invention.

FIG. 13 is a timing chart showing another fresh air spike method according to the present invention.

FIG. 14 is a timing chart showing another fresh air spike method according to the present invention.

FIG. 15 is a diagram showing the relationship between the calculated pressure difference A P c around D P F and the allowable pressure difference P t at that time. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described using the drawings.

FIG. 1 shows a schematic view of a cylinder of DE used in the PM oxidation method of the present invention. (A) shows the vicinity of the bottom dead center before the piston bottom dead center, and (b) shows the vicinity of the bottom dead center after the piston bottom dead center. Both (a) and (b) are the intake strokes. As shown in (a), the intake air flow is throttled by the intake air throttle 24 in the intake air passage so that the fuel flow approaches 1 as much as possible, and the air intake valve 52 is opened to introduce air into the cylinder 58. Insert (indicated by A in the figure). Then, as shown in (b), by closing the intake valve 52 and opening the exhaust pulp 54 near the piston 60 bottom dead center, the exhaust gas once exhausted to the exhaust passage A portion of the gas can reverse flow into the cylinder 58 (indicated by B in the figure) to raise the temperature of the exhaust gas. The intake throttle 24 can be throttle pulp, the intake valve 52 is an intake valve of a cylinder head, and the exhaust valve 54 is an exhaust valve of the cylinder head. In the present invention, to periodically open the intake throttle 24 and supply fresh air to the DE 10 (in the present invention, it may be referred to as “new air spike”) is to reduce the amount of inflowing air. This is done by periodically opening the intake throttle 24 provided in the unit, but it is sufficient to set the opening of the intake throttle 24 to 60 seconds or less every 30 minutes after the intake throttle 24 has been opened for 9 minutes. Further, the aperture is opened for less than 30 seconds every 30 minutes, 9 seconds for less than 15 seconds, 9 seconds for less than 5 seconds, aperture less than 3 seconds Sufficient effects can be obtained with 60 seconds per minute and 1 second per 30 minutes.

FIG. 2 shows an example of the case of using μ D P F in the method of oxidizing PM of the present invention. The engine has four cylinders. First, the flow of air (exhaust gas) in the state where the switching valve 28 is closed will be described. The air that has passed through the intake throttle 24 is fed into the cylinder 5 8 of the DE 10 and burns with the injected fuel in the cylinder 5 8 (not depicted in FIG. 2) in the DE 10. The burned exhaust gas is sent to the DPF 30 through the exhaust manifold 14 (the exhaust port of the multi-cylinder engine) and through the auxiliary exhaust pipe 7 provided downstream of the exhaust manifold 14 (the exhaust port). . Details of μ D P F 30 will be described later. Exhaust gas purified by μ D P F 30 passes through the auxiliary exhaust pipe 7, passes through the main exhaust pipe 9, and is further purified by mD P F 40 and discharged. As described above, when the DE 10 is idling or at low load, the switching valve 28 is closed so that all the exhaust gas is sent to the DP F 30. Since μ D P F 30 has a smaller capacity than m D P F 40, the temperature rise is quick, and it has the effect of preventing the exhaust gas from being cooled while passing through the main exhaust pipe 9. At high load on DE, the switching valve 2 8 is opened and the exhaust gas passed through the exhaust manifold 1 4 passes through the auxiliary exhaust pipe 7 and the main exhaust pipe 9 and purified with both the μ DPF 30 and the mD PF 40 It is done.

Although four cylinders are used in this embodiment, six cylinders or other multiple cylinders may be used, or single cylinders may be used. Also, for mD PF 40 without / x DP F 3 0 Of course, in this case, the switching valve 28 and the auxiliary exhaust pipe 7 are not necessary. If it is equipped with AZ DPF 30 and mD PF 40 further, in addition to the switching valve 28 mentioned above, another switching valve will be installed upstream of DPF 30 of the auxiliary exhaust pipe 7 to increase the DE height. It is also possible that exhaust gas does not pass through ^ DPF 30 at the time of loading, and exhaust gas is sent only to mD PF 40. FIG. 3 is a schematic view of DPF 30. mD PF 4 0 also has large capacity but basically the same structure. It is a continuous regenerative DPF in which DO C and catalyst-loaded DPF are arranged. In the present invention, i DPF 30 can be made only of catalyst-supported DPF, and it is also possible to use DOC and DPF side by side.

(Test 1) Without "new air spike"

The engine is 4 HF 1 (one elf), displacement 4, 3 3 4 cc, supercharged, maximum output 1 3 5Z 3 20 0 (NetPS / rpm), maximum torque 3 2, 0/1 7 0 0 (Net kg-m / rpm) _N- row type machine injection, the one of the Heisei 1st year regulation was used. The cylinder is constructed as shown in FIG.

The fuel is low sulfurized light oil (34 _P pra), and the operation start conditions are: APP (Accelerator Pedal Position: 6% of accelerator opening), ITP (Intake Throttle Position: Opening ratio of intake throttle 24): 2 The engine speed was 988 rpm with 3%. The test was started when the temperature of the exhaust manifold 14 reached 240 ° C.

A 4-cylinder DE exhaust purification system was used, equipped with μ D P F 3 0 (auxiliary exhaust gas purification system) and mD P F 4 0 (main exhaust gas purification system) shown in Fig. 2. As shown in Fig. 3, At D P F 30 is a combination of D 65 C with a diameter of 65 mm and a length of 30 mm, and medium-supported D P F with a diameter of 65 mm and a length of 100 mm. All exhaust gases flow into the auxiliary purification system. During the test, the time to double the gas flow by setting APP to 12% exists for less than 5 minutes. Also, the capacity of mD P F 4 0 (main exhaust gas purification device) is 5 10 0 Occ.

The graph of the test result in Test 1 is shown in FIG. The vertical axis represents the temperature (° C) of the exhaust gas flowing into / i DPF 3 0 and the exhaust pressure (k Pa), and the horizontal axis T / JP2003 / 012476

12 Overtime (seconds). The thin, thick line is the DP F 30 inlet temperature, and the thin, thin line is the μ D P F 30 inlet pressure. The thick, thin line is the μ D P F 30 outlet temperature, and the thick, thick line shows the pressure at the DP F 3 0 outlet. The same is true for the graphs below. In the graph, the auxiliary exhaust gas purification device is referred to as D P F, and the same applies to the following graphs.

As can be seen from the graph, in test 1, when exhaust gas of about 280 ° C is supplied to DPF 30, PM is oxidized (μ DP F inlet temperature Ai DP F outlet), but μ DPF inlet The differential pressure at the outlet continued to rise, and the engine misfired at 1 50 k Pa (= 15, 2 96 mm Aq). This is due to the fact that the amount of soot accumulated inside the μ D P F is greater than the oxidation capacity of PM. Incidentally, the weight of D P F 30 was increased by 5.5 g.

(Test 2) When "new air spike" was performed

The system is the same as test 1, and test 1 and operation start with the exception that the fresh air spike (intake throttle 24 was opened fully) with an exhaust second stage cam lift set to 1.5 mm to 1 · O mm was performed. The conditions are the same. In Test 2, the fresh air supply was tested in 4 types of 1 minute, 30 seconds, 15 seconds, and 5 seconds for the opening of the air intake throttle 24 for the air intake throttle 24 of 9 minutes and 30 seconds. A graph of the test results in Test 2 is shown in FIG. During operation, I TP is changed as shown in the graph.

The vertical axis is the temperature (° C.) of the exhaust gas flowing into the μ DPF 30 and the exhaust pressure (k Pa), and the horizontal axis is the elapsed time (seconds). Considering that all four cylinders are scavenged in about 1 Z 8 seconds (the complete change of mixture) at 1 00 O rpm, the "new air spike" of about 5 seconds makes ^ DP F 3 0 It is calculated that the interior can be filled with sufficient exhaust gas about 160 times residual oxygen. In the part where I TP could be set to 2.3%, the inlet and outlet temperatures of DPF 30 are rising. ^ The increase in differential pressure at the inlet and outlet of DPF 30 is also clearly reduced compared to Test 1, and it can be seen that the “new air spike” decreases (regeneration of DFP). The differential pressure rise after the test for 12,000 seconds (3 hours and 15 minutes) is about 8.3 kP a, and the inside of the DPF 30 The weight of accumulated PM was 4.2 g.

(Test 3) When the time of “new air spike” and its timing were changed In Test 3, the operation start conditions are the same as in Test 2, and the time and timing of “new air spike” were changed. The system continues the same as Test 1, and continues the intake throttle 24 for 30 minutes and shortens the “new air spike” to 1 second, but the PM oxidation capacity of the DPF 30 does not decrease, and the difference It can be understood that the pressure does not show a large rise.

A graph of the test results in Test 3 is shown in FIG. I T P is changed during operation as shown in the graph. The weight of P M accumulated inside D P F 30 was 0.4 g. The “new air spike” only opens the intake throttle 24 fully, and since there is no change in generated output torque, there is no adverse effect on driving. If you dare to point out, the inspiratory noise rises, but there is no driver who notices it with a spike of one second in a few minutes.

FIG. 7 is a view showing the overall configuration of an exhaust gas purification apparatus for a diesel engine according to the present invention.

As shown in the figure, in the exhaust purification system of a diesel engine, there are a diesel engine 10 for which exhaust gas is to be purified, an intake manifold 12 for introducing fresh air to each cylinder of the diesel engine, and The control means 20 detects the amount of depression of the exhaust manifold 14 through which the exhaust gas discharged from each cylinder passes and the accelerator pedal for the driver to input information to control the output of the diesel engine. An acceleration position sensor 16 that transmits to the engine, and a rotation sensor that reads the rotation angle of the crank shaft of the diesel engine and outputs a rotation angle signal (including the pulse of the engine rotation speed signal) to the control unit 20 And eight are provided. The depression amount of the accelerator pedal is transmitted to a fuel injection device (not shown), which makes it possible to control the output of the engine.

In the exhaust gas purification system of diesel engine, an intake air temperature sensor 22 for measuring the intake temperature of the engine and an intake air throttle for adjusting the amount of fresh air taken into the cylinder by throttling the engine intake. 2 4 (Intake flow rate adjustment Control valve (including the function of a joint valve) and exhaust throttle 26 that performs control to increase exhaust gas volume returned to the cylinder by increasing exhaust pressure by throttling the engine exhaust, and switching valve that switches the exhaust flow path 2 8 And are provided.

Of the two types of DPFs that capture and process PM contained in the exhaust of diesel engines, mD PF 40 is effective in capturing PM contained in a large amount of exhaust emitted when the diesel engine is heavily loaded. It is a large DPF that oxidizes in a controlled manner. On the other hand, μ D P F 30 is a small D P F that collects and effectively oxidizes soot contained in a small amount of exhaust gas emitted at low load of a diesel engine. The switching valve 28 has a function of switching the flow path of exhaust gas between mD P F 40 and / i DP F 30.

In addition, the exhaust gas purification system of the diesel engine: // Exhaust temperature sensor 32 for measuring the temperature of exhaust flowing into DP F 30; main exhaust pipe 34; An exhaust gas temperature sensor 42 for measuring the temperature of the exhaust gas flowing into the m DPF 40 is provided.

Also, as shown in the figure, the switching valve 28 is provided between the exhaust gas manifold 14 of the diesel engine 10 and the mD PF 40, and the μ DPF 30 is closer to the switching valve 28 than the mD PF 40. It is provided in the position. The switching valve 28 may have a gap (mechanism) in the switching valve 28 for flowing a small amount of exhaust gas to the μ DPF 30 side even when the exhaust gas flow path is switched to the mDPF 40 side. A bypass channel (mechanism) may be provided so that exhaust gas always flows to 30. In addition, an adiabst screen may be provided to control the flow rate of a small amount of exhaust gas flowing to the μ D P F 30.

The intake flow control valve such as the intake throttle 24 is equipped with a valve actuator for throttling the intake, and the intake throttle valve is set to an arbitrary opening degree based on the control information output from the control means 20. It is possible. The actuator is provided with a function of adjusting the intake flow rate of the diesel engine by setting the opening degree specified based on the control command output from the control means 20, and the electric power source is electricity. Is an expression actuator Alternatively, a control valve for negative pressure air may be controlled based on a control command output from the control means 20, and a negative pressure type actuator using the negative pressure air as a power source may be used. Alternatively, a control valve for negative pressure air may be controlled based on a control command output from the control means 20 to use a negative pressure type actuator with the negative pressure air as a power source.

In addition, the intake throttle 24 may be provided with an IT opening sensor for detecting the throttle opening of the intake, and an opening signal for feedback of the IT opening may be output to the control stage 20. Further, in the figure, although the embodiment in which one intake throttle 24 is provided in the manifold line of the intake manifold 12 is described, the present invention shows the installation position etc. of the intake throttle 24 in FIG. It is not limited as such, and may be provided independently in the branch to each cylinder in the intake manifold 12.

Also, in the exhaust gas purification device for a diesel engine shown in FIG. 7, the flow rate of the exhaust gas to be recirculated is adjusted when the exhaust gas obtained from the exhaust manifold 14 is cooled and recirculated to the intake manifold 12 or the like. An external EGR valve 44 is provided. The external EGR valve 44 can appropriately set the opening / closing timing and the opening degree of the control means 20 based on parameters such as the accelerator depression amount and the engine speed.

In the example of the external EGR shown in FIG. 7, the exhaust gas to be recirculated is acquired from the exhaust manifold 14. However, the present invention is limited to the example of acquiring the exhaust gas from the exhaust manifold 14. Instead of getting the exhaust gas cleaned from the rear of m DPF 40 and actively reducing the temperature of the exhaust, return it to the front of intake manifold 12 or intake throttle 24 via the EGR cooler. Let's configure it. The engine coolant may be used as the refrigerant of the EGR cooler, or the traveling wind of the vehicle may be used.

Furthermore, according to the present invention, internal EGR with a special exhaust cam is used to recirculate high temperature exhaust directly to the combustion chamber before combustion, especially in low rotational speed and low load operating areas where exhaust temperature is particularly low. A mechanism is used to supply high temperature exhaust gas to the cylinder before combustion. The exhaust throttle 26 may be provided downstream of the i DP F 30 (exhaust throttle 26 B), or upstream (exhaust throttle 26 C) of the mD PF 40 or downstream (exhaust throttle 26 D) It is also good. Further, the exhaust gas passing through the μ DPF 30 may be released directly to the atmosphere without passing through the mD PF 40.

Even when multi-cylinder exhaust pipes are gathered, it is usual to set the exhaust pipe to a size that enhances the exhaust efficiency by utilizing the pulsation of the exhaust gas, but it flows into the mD PF 40 Placing the μ DPF 30 close to the exhaust port to secure the exhaust temperature above the specified temperature may cause exhaust interference or increase the bombing loss, resulting in deterioration of the exhaust efficiency. In the operating region where the temperature of exhaust reaching mD PF 40 is high, it is desirable to use mD PF 40 as much as possible.

As a continuous regeneration type exhaust gas purification apparatus, a continuous regeneration type exhaust purification apparatus is constituted by the diesel oxidation catalyst D OC in the front stage and the PM collection filter 1 in the rear stage, or as a single PM collection filter with a catalyst support type. It is common to use.

Also, in the diesel engine 10, an air pump 46 that outputs the positive pressure or negative pressure air by obtaining the rotational force of the diesel engine crankshaft, and the positive pressure or negative pressure air output by the air pump 46 An air tank 48 is provided to save The negative pressure air stored here is generally used by the master pack to assist the braking force when braking a small vehicle. In addition, the stored positive pressure air is used for generating braking force in medium and large vehicles, and for air panels in suspension systems. In the present invention, a power source for operating the intake flow control valve (intake throttle 24 or the like), the exhaust throttle 26, the switching valve 28, the EGR valve 44 or the like using the stored positive pressure or negative pressure air. It is also possible to use

The exhaust purification system of the diesel engine 10 also includes a differential pressure sensor 33 for measuring the pressure difference between the inlet and the outlet of the DPF 30 (a pressure difference around the DPF 30), and an mD PF A differential pressure sensor 43 is provided to measure the pressure difference between the inlet and outlet of the 40 (pressure difference around the mD PF 40). Ru. The control means 20 reads a pressure difference around the μ DPF 30 or m DPF 40 detected by the differential pressure sensor 33 or the differential pressure sensor 43 via an A-D converter or the like to obtain a predetermined pressure difference. (It may be a variable determined based on the engine speed, engine displacement, volumetric efficiency, volumetric flow of exhaust flowing through the DPF, density of the intake air, etc.)判断 ^ ^ ^ ^ μ DPF 30 or m DPF 40 It is judged that the control command to increase the intake flow rate to the intake flow control valve such as the intake throttle 24 etc. It is possible. At this time, if a predetermined time has elapsed (after a first predetermined time) and the pressure difference detected by the differential pressure sensor is equal to or greater than a predetermined threshold, the intake flow control valve such as the intake throttle 24 or the like. Control command may be output to increase the intake flow rate.

In addition, while the control means 20 is outputting a control command for increasing the intake flow rate to the intake flow control valve such as the intake throttle 24 etc., the pressure difference around the μ DPF 30 or m DPF 4 0 is predetermined If it is judged that the pressure difference is below the pressure difference of PM, the PM deposited on μ DPF 30 or m DPF 40 burns and is converted to CO ₂ and it is judged that the amount of PM deposited decreases. Thus, it is possible to output a control command for returning the intake flow rate to the original intake flow rate to the intake flow control valve such as the intake throttle 24 and the like. '

Thus, based on the pressure difference input from the differential pressure sensor 3 3 or the differential pressure sensor 4 3, information for controlling the intake flow control valve such as the intake throttle 24 is output. Even if PM is excessively deposited in the DPF, it is possible to detect this early and burn PM appropriately to continuously regenerate the DPF.

In the example shown in FIG. 7, the high temperature exhaust gas fed into the combustion chamber before combustion is adjusted by using the EGR pulp 44. However, instead of using the EGR valve 44 described above, FIGS. High temperature exhaust gas may be supplied to the cylinder before combustion by an EGR mechanism (internal EGR system) using a special exhaust cam shown in 9.

Also, as shown in Figure 7, the intake path of the diesel engine 10 The intake flow control valve 25 for bypassing the air throttle 24 and the intake spike control means 21 for outputting a control command for adjusting the intake flow rate passing through the intake flow control valve 2 5 may be provided independently. . By providing the intake flow control valve 25 and the intake spike control means 21 and their paths independently, the present invention can be applied to a diesel engine provided with the existing intake throttle 24 and the control means 20. Such exhaust gas purification devices can be easily retrofitted to effectively oxidize the PM deposited on the DPF and continuously regenerate the DPF. FIG. 8 is a cross-sectional view of a combustion chamber portion of a diesel engine equipped with an EGR mechanism that directly returns exhaust gas to a cylinder before combustion.

As shown in the figure, a cylinder head 50 having an intake valve 52, an exhaust valve 54 and an injection nozzle 62 and forming a combustion chamber in the combustion chamber portion of the diesel engine, Biston 60 which receives combustion pressure and transmits torque to the crankshaft, and a cylinder 58 which is a sliding surface of piston 60 are provided.

The exhaust cam 56, which defines the exhaust timing and lift amount of the exhaust valve 54, is the first cam peak that opens the exhaust valve 54 to perform the normal exhaust process, and the exhaust near the end of the intake process. Two cam peaks are provided with a second cam peak which opens the valve 54 slightly.

In this way, by forming two cam peaks on the exhaust cam 56, the exhaust pulp 54 is opened in the normal post-combustion exhaust process, and the post-combustion exhaust gas is discharged to the exhaust manifold. Near the end, it is possible to provide an exhaust pulp 54 with a function to open an appropriate amount again and return the exhaust to the cylinder (or combustion chamber) before combustion.

FIG. 9 is a diagram showing the relationship between the position of piston 60 and the lift amount of intake valve 52 and the lift amount of exhaust valve 54.

Similar to the intake and exhaust timing of a normal diesel engine, the exhaust valve 54 starts to open before combustion of the piston 60 reaches the bottom dead center, and exhaust of combustion gas is started. As the crankshaft rotates approximately half turn and Bison 6 0 approaches the top dead center, it starts to open the intake valve near the end of the exhaust process 2003/012476

Start introducing fresh air for the next combustion.

Near the end of the intake stroke when the piston approaches the bottom dead center again, the pressure in the exhaust manifold 14 is higher than the pressure in the cylinder 58 even in a general engine, so here again the exhaust valve 5 When 4 is opened, the high temperature exhaust gas flows back into the cylinder from the exhaust manifold 14. The exhaust gas is charged into the cylinder together with the fresh air taken in.

The compression process is started after Biston passes the bottom dead center. Generally, the relationship between the temperature T H 1 and pressure P 1 of the gas in the cylinder before compression and the gas temperature T H 2 and P 2 after completion of the compression step is expressed by the following equation.

k: specific heat ratio of gas (in the case of air 1.

Diesel engine compression ratio,

= 2. 2 0 8 Therefore, if the high temperature exhaust after combustion is mixed into the air before compression and the temperature of the gas before compression rises by 10 ° C., the temperature after compression rises by 2 2.8 ° C. In this case, combined with the fact that there is less excess air, the temperature of the exhaust after combustion also rises, which makes it easier to continuously regenerate PM (including soot, soot, etc.) collected in the DPF soot. . In addition, even when passing the exhaust gas through the current NOx reduction catalyst, control for maintaining the exhaust gas temperature in a wide range of operating conditions is essential to make the catalyst function effectively.

If simply raising the exhaust temperature, set the lift of the second cam peak of the exhaust cam high or set the operating angle wide, and increase the amount of exhaust gas flowing back into the cylinder to set the exhaust temperature high. It is possible.

However, because the lift of exhaust pulp 54 by the second cam peak lifts over the entire engine operation area, the exhaust pressure is high in the area where the amount of air decreases compared to the amount of fuel supplied as in high load. As a result, the backflow of the exhaust gas also increases, which tends to result in incomplete combustion, and a large amount of PM (soot, soot, smoke, etc.) is generated beyond the amount that can be regenerated in the DPF.

If PM occurs in a large amount exceeding the DPF's renewable capacity, In addition, PM deposits and causes a rapid increase in exhaust pressure, which significantly deteriorates fuel efficiency. In addition, if the exhaust temperature rises due to fluctuations in operating conditions, a large amount of deposited PM may start combustion in a chain, leading to damage to the DPF.

Conversely, if the lift of the exhaust valve 54 due to the second cam peak is set low or the operating angle is set narrow, the reverse flow rate of the exhaust into the cylinder 58 will be small, and the exhaust temperature will be low when the load is low, etc. However, the engine operating range where the predetermined exhaust temperature can be maintained is narrowed.

There are also known techniques (such as a variable valve timing mechanism) for shifting the cam height of the exhaust cam or changing the lift amount of the exhaust pulp, but the present invention in the form of a retrofit for a diesel engine vehicle currently traveling. If you install the exhaust purification system of the diesel engine concerned and try to reduce the PM that is discharged, it would be cheaper to do remodeling work if it had a fixed cam pile So convenient.

Also, in general, in low load operation areas where the amount of exhaust is small, there are many cases where the exhaust temperature does not rise sufficiently even if the intake throttle 24 and the exhaust throttle 26 are controlled. Therefore, if the DPF is provided only at the end of the extended exhaust pipe for the purpose of improving the exhaust efficiency etc., the exhaust gas temperature will drop before the exhaust reaches the DPF, so PM contained in the exhaust will be included. There is a problem that continuous regeneration with DPF can not be performed.

Therefore, first, in order to finely adjust the flow rate of the exhaust gas flowing back into the cylinder, the intake throttle 24 is provided, and in a region where the exhaust temperature tends to be low as in low load operation, the exhaust manifold 14 directly below By flowing the exhaust gas through the μ DPF 3 0 provided in, it is possible to maintain the exhaust temperature in a wider load range and reduce the amount of soot emissions. In areas where sufficient exhaust temperature can be obtained, such as during high-load operation, fuel efficiency and fuel output can be maintained by using m DPF 40 mainly to ensure exhaust efficiency similar to that of a conventional diesel engine. It is possible to

In addition, during idling and in the low-load low-rotation operation area, the intake throttle 2 4 Generally, there is a region where the exhaust gas temperature does not reach a predetermined temperature even if In this case, by throttling the intake throttle 24 and throttling the exhaust throttle 26, it is possible to increase the exhaust pressure and increase the amount of exhaust returned to the cylinder to secure the exhaust temperature. Also, in this way, it is possible to perform a process of continuously regenerating PM contained in exhaust gas in a wider operating area.

FIG. 10 is a view showing an I-TP control map used for an exhaust gas purification apparatus of a diesel engine according to the present invention.

The ITP map shown in the figure is stored in storage means such as a memory provided in the control means 20. The control means 20 receives the accelerator pedal depression amount (APP) input from the accelerator position sensor 16 and The I / P map recorded in the recording means is referred to based on the engine speed (Ne) input from the rotation sensor 18 and the intake throttle 24 (I TP open and exhaust throttle 2 6 And information to control the switching valve 28. Note: The recording means for recording the TP map may be provided inside the control means 20, or provided separately outside the control means 20 for control It may be communicably connected to the means 20.

As shown in the figure, for example, when the engine speed is 100 Orpm and the driver is depressing the accelerator pedal by 40%, the exhaust gas temperature rises to a predetermined temperature under a medium load operating condition. Therefore, the control means 20 outputs information for controlling the intake throttle 24 so that the opening degree is 100% (I TP = 100%). Further, a control signal is output to the switching valve 28 so as to flow the exhaust gas to the mDP F 40.

In addition, when exhaust gas is flowing to the mD PF 40 in this way, the switching valve 28 and the like are controlled so that a small amount of exhaust gas also flows to the μ DPF 30 instead of flowing all exhaust gas only to the mD PF 40. It may be configured. Even when using mD PF 40, it is possible to maintain the temperature of DP F 30 at a predetermined temperature by continuing to flow a small amount of exhaust gas to μ DPF 30, reducing the load depending on the operating conditions. Even when switching the flow of exhaust, Immediately after switching, ^ DPF 3 0 can process PM continuously. Therefore, it is possible to continuously regenerate PM even when the driving situation changes suddenly.

If the above-mentioned engine speed is medium load operation condition of 1 0 0 O rpm and the driver returns the depression amount of the accelerator pedal from 4 0% to 3 0%, the control means 20 becomes ITP. Referring to the control map, output control information to throttle the intake throttle 2 4 to 30%.

Then, based on the control information acquired from the control means 20, the intake throttle 24 throttles the intake path to 30% with a shirt or butterfly pulp or the like to reduce the flow rate of intake. Then, the amount of air taken into the cylinder of the intake process decreases, so the pressure in the cylinder 下がり decreases near the end of the intake process, and the amount of exhaust gas flowing back into the cylinder increases. Then, since the temperature of the gas before compression rises, the temperature of the exhaust after compression and combustion rises, and it becomes possible to maintain the temperature of the exhaust flowing into m DPF 40 at a temperature that allows continuous regeneration of PM. .

If the driver further returns the accelerator pedal depression amount to around 25% when the engine speed is 100 o rpm, the control means 20 refers to the ITP control map, Outputs control information that throttles the intake throttle 24 to approximately 10%.

Then, the intake throttle 24 squeezes the intake path to about 10% based on the control information acquired from the control means 20 to further reduce the flow rate of the intake. Then, the amount of air taken into the cylinder of the intake process further decreases, so the pressure in the cylinder further decreases near the end of the intake process, and the amount of exhaust gas flowing back into the cylinder increases. Then, since the temperature of the gas before compression rises, the temperature of the exhaust after compression and combustion rises, and it becomes possible to maintain the temperature of the exhaust flowing into m D P F 40 at a temperature at which PM can be continuously regenerated.

The control information of the throttle amount of the intake throttle 24 outputted by the control means 20 may be linearly interpolated between the ITP 100% line and the ITP 30% line shown in the figure. To make the curve capture interval more than a quadratic curve, Pad control may be performed.

If the driver further returns the accelerator pedal depression amount to around 2 3% while the engine speed is 100 0 rpm, the control means 20 refers to the ITP control map. The control valve 28 is controlled to output a control signal so as to flow the exhaust gas to the μ DPF 30 and also to output control information for opening the intake throttle 24 to 100%.

In this state, the exhaust temperature decreases because the intake throttle 24 is opened, but the DPF passing through the exhaust is switched from the large m DPF 40 to the small m / z DPF 30 provided directly under the exhaust manifold. Since the exhaust resistance increases and the engine exhaust pressure becomes higher than in m DPF 40, the exhaust backflow increases and the exhaust temperature rises. The temperature of the exhaust flowing into μ DPF 30 continuously regenerates the air It is possible temperature. In addition, since the flow rate of the exhaust gas is small in the operating state where the load is low, even small D PF can be sufficiently processed, and since the intake air is not throttled, it is possible to prevent the deterioration of the fuel efficiency and the reduction of the output.

In addition, when determining the capacity (size) of μ D P F 30 at the design stage, it should be determined according to the exhaust temperature characteristics of the diesel engine that processes the exhaust and the exhaust flow. In addition, the capacity (size) of m D P F 40, the length of the exhaust pipe up to each D P F, the mounting position of the switching valve 28, etc. are appropriately determined depending on the type of vehicle and engine configuration.

If the driver further returns the accelerator pedal depression amount to around 10% while the engine speed is 100 ° O rpm, the control means 20 refers to the ITP control map. Outputs control information to throttle the intake throttle 2 4 to approximately 5%. Further, control information for narrowing the exhaust throttle 26 to a predetermined opening degree is also output.

The intake throttle 24 throttles the intake path to about 5% based on the control information acquired from the control means 20 to reduce the flow rate of the intake. In addition, since the exhaust throttle 2 6 is also narrowed to a predetermined opening degree, the exhaust pressure in the exhaust manifold 14 is maintained or the exhaust pressure rises. Then, the amount of air taken into the cylinder of the intake process further decreases, so the amount of exhaust gas flowing back into the cylinder increases. Since the temperature of the gas before compression further rises, the temperature of the exhaust after compression and combustion rises, and it becomes possible to maintain the temperature of the exhaust flowing into the DPF 30 at a temperature that allows continuous regeneration of PM.

At this time, the throttle amount of the exhaust throttle 26 may also be controlled in accordance with the depression amount of the accelerator pedal or the engine speed. In this case, the ITP control map shows that if the engine speed is lower than the predetermined speed and the accelerator pedal depression amount is smaller than the predetermined depression amount, the exhaust throttle 26 is narrowed. The control means 20 inputs the depression amount of the accelerator pedal and the engine speed, refers to the ITP control map, and outputs the information for controlling the exhaust throttle 26. Good.

Also, as shown in the figure, the IT control map has an area for performing control for throttling the intake as the engine speed decreases and the accelerator pedal depression amount decreases.

Also, as shown in the figure, the ITP control map has an area for performing control to switch the exhaust gas from m DPF 4 0 to At DPF 3 0 as the engine speed decreases and the accelerator pedal depression amount decreases. ing.

Further, as shown in the figure, the IT control map has an area for performing control for throttling the exhaust as the engine speed decreases and the accelerator pedal depression amount decreases.

The control means 20 also controls the intake throttle 24, the exhaust throttle 26 or the exhaust throttle 26 based on the exhaust temperature input from the exhaust temperature sensor 32 that measures the temperature of the exhaust flowing into the μ DPF 30 or m DPF 40. Information for controlling the switching valve 28 may be output to control the exhaust temperature within a predetermined temperature range. In this case, the control means 20 may perform a process of shifting the ITP control map according to the exhaust temperature, or control information output to the intake throttle 24, the exhaust throttle 26 or the switching valve 28. Process to add or multiply predetermined coefficients. It may be connected.

As a general trend, control information for throttling the intake throttle 24 and control information for throttling the exhaust throttle 2 6 etc. are output when the exhaust temperature is low, but the switching valve according to the operating condition of the diesel engine 10 Control information for switching the 8 to the DPF 30 may be output.

Also, as shown in FIG. 7, an intake temperature sensor 22 for measuring the intake temperature of the diesel engine is provided in the intake manifold 12 or the like, and the control means ²⁰ controls the intake temperature input from the intake temperature sensor 22 Information for controlling the intake throttle 24, the exhaust throttle 26, or the switching valve 28 may be output based on this. In this case, the control means 20 may perform processing to shift the ITP control map according to the intake temperature, or to the control information output to the intake throttle 24, the exhaust throttle 26 or the switching valve 28. A process of adding or multiplying predetermined coefficients may be performed.

As described above, the control means 20 inputs the exhaust gas temperature or the intake air temperature to control the exhaust gas temperature, so that even if the temperature of the exhaust gas changes due to the deviation from the stable use condition, the predetermined exhaust gas is produced. It is possible to maintain the temperature.

The control means 20 may also output an instruction to open the intake throttle 24 when an instruction to operate the exhaust brake is input from the exhaust brake switch. This is to prevent the exhaust pressure from rising even if the exhaust brake is operated while the intake is throttled, because the amount of air taken in is small, so that the effectiveness of the exhaust brake is prevented from decreasing.

FIG. 11 shows a signal processing block diagram of the control means 20 according to the present invention. According to the figure, the information transmitting and receiving unit of the control means 20 includes an antenna 26 used as a wireless communication means, an operating condition of the diesel engine, a pressure difference before and after the DPF, a temperature in the DPF, etc. In order to wirelessly transmit and receive various information, there are provided transmitting and receiving means 265 for converting data into a predetermined format.

Also, the control means 20 has the operating condition and traffic information of the diesel engine. A display unit 2 72 for displaying information such as images and characters, and a display interface 2 7 3 for outputting an image signal for display to the display unit 2 7 2 based on an instruction from the information processing unit. And the driver etc. input means such as operation button

An input interface 2 7 1 which reads various commands input via 2 0 7 and transmits them to an information processing means to be described later, or outputs a display command to notification means such as an LED based on an instruction from the information processing means Is provided.

In addition, an acceleration signal such as a voltage or current output from the accelerator position sensor 16, the intake air temperature sensor 22, the differential pressure sensor 33, or the difference is input to the control means 20, and information processing is performed. An A-D converter 260 is provided which converts the digital data into readable digital data and outputs the digital data.

In addition, various information such as the signal of the operation status of the switching valve 28 is input to the control means 20 according to the number of revolutions of the diesel engine, and data which can be read by the information processing means 280 is obtained. IZO 2 7 6 is provided to convert. Also, IZO 2 76 controls various control devices such as intake throttle 24, intake flow control valve 25, exhaust throttle 26 and switching valve 2 8 based on the command from information processing means 280. It is possible to output control commands to

Further, the control means 20 includes an information processing means (CPU) 280 for performing overall control of the control means 20, a processing program executed by the information processing means 280, various constants, and communication networks. Records various information such as address, attribute information, URL (Uniform Resource Locators), identification information specific to the driver or vehicle, gateway information, DNS (Domain Name System) etc. when connecting with other communication devices that exist. A power render clock with a memory 2 8 1 consisting of a ROM, a RAM that will be a working area when the information processing means 2 280 executes processing, and a timer function that keeps time and measures time. Two hundred and ninety are provided.

Information processing means 2 80 in control means 2 0 and display interface 2 7

3, input interface 2 7 1, memory 2 8 1, A-D converter 2 6 0, The respective peripheral circuits including the 1/0 2 7 6 and the calendar clock 2 0 0 9 are connected by a bus 2 2 9 9 and the information processing means 2 is based on the processing program executed by the information processing means 2 8 0. It is possible for 80 to control each peripheral circuit.

The switching valve 28 obtains the control command output from the information processing means 280 through an interface such as I / O 2 76, etc., based on the control command output from the control means 20. The exhaust path of the diesel engine can be switched to μ DPF 30 or m DPF 40. In addition, the intake flow control valve such as the intake throttle 24 etc. is a control means by acquiring the control command output from the information processing means 280 through the interface of IZ 0 2 7 6 etc. It is possible to adjust the intake flow rate of the diesel engine based on the control command output from the engine.

In addition, the force rendering clock 290 starts measurement of a predetermined time based on the instruction of the information processing means 280, and outputs the elapsed time of the measured predetermined time to the information processing means 280. It has a timer function. In addition, it is possible to set multiple timers simultaneously.

The differential pressure sensor 33, 34 detects a pressure difference around the μ DPF 30 or m DPF 40, and the information of the detected pressure difference is converted into an A-D converter 2 60 etc. in the control means 20. It is possible to transmit to the information processing means 280 via the interface.

The control means 20 including the information processing means 280 has a pressure difference detected after the first predetermined time measured by the first timer has elapsed and detected by the pressure difference sensor 33 or the pressure difference sensor 43. If it is equal to or greater than the predetermined threshold value, a control command to increase the intake flow rate is output to the intake flow rate control valve such as the intake throttle 2 4 and the intake throttle is detected after the second predetermined time measured by the second timer It is possible to output a control command to restore the intake flow rate to the original intake flow rate to the intake flow rate adjustment valve such as 2 4.

Further, the control means 20 including the information processing means 2 8 0 is used to control the intake flow control valve such as the intake throttle 24 after the first predetermined time measured by the first timer has elapsed. A control command to increase the intake flow rate is output, and a control command to return the intake flow rate to the original intake flow rate is output to the intake flow control valve such as the intake throttle 24 after the second predetermined time measured by the second timer has elapsed. It is possible to Further, the control means 20 including the information processing means 280 outputs a control command of the intake flow rate control valve such as the switching valve 28 and the intake throttle 24 according to the depression amount of the accelerator pedal and the engine speed. At the same time, a control command for increasing the intake flow rate is output to the intake flow control valve after the first predetermined time measured by the first timer has elapsed, and the second predetermined time measured by the second timer has elapsed It is possible to output a control command for returning the intake flow rate back to the original intake flow rate to the intake flow control valve later.

Further, the control means 20 including the information processing means 280 outputs a control command of the intake flow rate control valve such as the switching valve 28 and the intake throttle 24 according to the depression amount of the accelerator pedal and the engine speed. In addition, if the pressure difference detected by the differential pressure sensor 33 or the differential pressure sensor 43 is equal to or greater than a predetermined threshold after the first predetermined time period measured by the first timer has elapsed, The control command for increasing the intake flow rate is output to the intake flow control valve such as 4th, and the intake flow rate is originally set to the intake flow control valve such as the intake throttle 24 after the second predetermined time measured by the second timer. It is possible to output a control command to return to the intake flow rate.

Further, the control means 20 including the information processing means 280 is after a first predetermined time measured by the first timer and before a second predetermined time measured by the second timer. And a control command to increase the intake flow rate to the intake flow control valve such as the intake throttle 24 after the third predetermined time period measured by the third timer has elapsed, and the fourth timer measures the fourth It is possible to output a control command for returning the intake flow rate to the original intake flow rate to the intake flow control valve such as the intake throttle 24 after a predetermined time has elapsed.

Further, the control means 20 including the information processing means 280 is a pressure difference which is detected after the first predetermined time period measured by the first timer has elapsed and which is detected by the differential pressure sensor 33 or the differential pressure sensor 43. If is greater than or equal to a predetermined threshold, and Before the second predetermined time measured by the timer, the control command to increase the intake flow rate is output to the intake flow control valve such as the intake throttle 24 after the third predetermined time measured by the third timer. It is possible to output a control command to return the intake flow rate to the original intake flow rate to the intake flow control valve such as the intake throttle 24 after the fourth predetermined time measured by the fourth timer has elapsed.

As described above, the combustion of PM in the continuous regeneration type D P F is said to be 350 ° C. or more for the catalyst-supporting D P F and 250 ° C. to 45 ° C. for the D O C. The exhaust temperature during normal speed driving of a normal diesel engine is 70 ° C to 1000. Since it is C, it does not reach an exhaust temperature (about 260 ° C. or more) at which PM can be oxidized by DPF. Therefore, the internal EGR and external EGR are provided to raise the exhaust temperature at low load, and the intake throttle 24 is further narrowed to supply a large amount of exhaust into the cylinder before combustion, thereby reducing the exhaust temperature at low load. I try to raise it.

However, depending on the driving condition of the vehicle, as shown in Fig. 4, the differential pressure between the DPF inlet and outlet continues to increase, and PM is not accumulated in the DPF and is accumulated in the DPF to clog the filter. In some cases, it may become impossible to drive. In addition, when exhaust gas temperature rises rapidly due to a change in vehicle operating conditions to a high load side with a large amount of PM deposited in the DPF, a large amount of PM accumulated in the DPF is burned rapidly to cause the DPF to The carrier may be damaged.

Therefore, in the present invention, control is performed to open the intake throttle 24 for a short time based on a predetermined time interval or the like, and intermittently absorb more oxygen than the amount of oxygen necessary for combustion of the diesel engine. There is. The addition of the flow rate of fresh air supplied to the diesel engine intermittently as described above is referred to as fresh air spike in the present invention.

In the PM oxidizer of a diesel engine, the following reactions are progressing as reactions involved in PM combustion.

c + o ₂ → co ₂

2 C + 0 ₂ → 2 CO 2 CO + 0 ₂ → 2 CO a

2NO + 0 ₂ → 2N 0 ₂

2N 0 ₂ + C → ₂ NO + C 0 ₂

All these reactions are further promoted as the intake air flow rate of the diesel engine is intermittently increased by the fresh air spike, and the amount of oxygen contained in the exhaust gas is increased during that period.

The carbon dioxide generated by these reactions is released to the atmosphere as it is. FIG. 12 is a timing chart showing a fresh air spike method according to the present invention.

In the figure, how the state of the first timer T 1 and the second timer T 2 (H i or L o) and the intake flow rate of the diesel engine transit according to time It shows.

In the present invention, as shown in the figure, the calendar clock 2 90 (including the function of the first timer 1 T 1) periodically (with a predetermined interval) based on the instruction of the information processing means 2 80. The elapsed time of the first predetermined time (t 1) is measured.

When the information processing means 280 has acquired, via the bus 2 9 9, information that the calendar clock 290 (first timer) has measured the lapse of the first predetermined time (t 1), Means 280 instructs calendar clock 2 90 (including the function of second timer T 2) to start the measurement of the second predetermined time (t 2), and the first timer measured by the first timer. After a predetermined time has elapsed, a control command to increase the intake flow rate is output to the intake flow control valve such as the intake throttle 24 or the like. Then, the information processing means 280 outputs an instruction to reset the first predetermined time (t 1) to the force rendering clock 2 90 (first timer), and the measurement of the first predetermined time is newly started again. To indicate.

Next, the calendar clock 290 (including the function of the second timer) measures the elapse of the second predetermined time (t 2) based on the instruction of the information processing means 280. Information that the information processing means 2 80 has measured that the force rendering clock 29 0 (second timer) has elapsed the second predetermined time (t 2) is sent via the bus 2 9 9 (If the second predetermined time measured by the second timer has elapsed), the intake flow rate is adjusted to the original intake flow rate for the intake flow control valve such as the intake throttle 24 (before the start of the new air spike) Output a control command to restore the original intake flow rate of Then, the information processing means 280 outputs a command to reset the second predetermined time (t 2) to the calendar clock 2 90 (second timer), and the measurement of the next second predetermined time is performed. Prepare for.

The intake flow control valve such as the intake throttle 24 adjusts the intake flow rate of the diesel engine based on the control command acquired from the information processing means 280. In the present invention, in a diesel engine that oxidizes PM accumulated in the DPF, the intake air is throttled using an intake throttle 24 or the like to maintain the exhaust temperature at a low load at a predetermined temperature or higher. By controlling the intake flow control valve such as the intake throttle 24 to open for a short time based on a predetermined time interval etc., it sucks more oxygen than the amount of oxygen necessary for the combustion of the diesel engine intermittently. Is possible. This makes it possible to accelerate the various reactions of oxidation of PM (carbon) deposited in DPF to convert PM into carbon dioxide and release it to the atmosphere.

In addition, even if the internal EGR and external EGR are provided in the diesel engine 10 to increase the exhaust temperature at low load, and reduce the intake throttle 24 to increase the exhaust temperature at low load, PM Oxidation reactions are promoted, and PM (carbon) deposited in the DPF is oxidized and released to the atmosphere.

It is effective to squeeze the intake throttle 24 in order to suppress the decrease of the exhaust temperature and maintain the high temperature when the engine load is low. However, in order to further enhance this effect, the engine together with the intake throttle 24 throttling The exhaust temperature can be maintained even higher by opening a small amount of the exhaust valve 54 at the timing near the bottom dead center of the intake stroke and by making the exhaust flow backflow and recirculate (also called internal EGR). At this time, although the temperature of the exhaust gas flowing into the DPF rises, the DPF is filled with oxygen further decreased by the recirculation. At that time, after the passage of a certain interval (after the passage of the first predetermined time) By opening the intake throttle 24 for a very short time, the amount of exhaust gas recirculation decreases and the amount of fresh air intake increases, and the amount of oxygen around the PM accumulated in the exhaust purification system for a very short time It will increase.

Even for a short time, since the amount of oxygen in contact with PM increases within the DPF, PM combustion is temporarily accelerated rapidly, and a fire species is formed, which spreads to burn the next PM. . According to the present invention, the effect is maintained to some extent even after the introduction of new air, and when PM is deposited, new new air is introduced again and the phenomenon that oxidation of PM is promoted is repeated. Then, the PM trapped and accumulated in DPF burns, and the function of continuously regenerating DPF is significantly promoted.

As a result, even when internal EGR is used, the function of combustion of the PM trapped and accumulated in the DPF and the regeneration of the DPF continuously is consequently significantly promoted, and the PM in the DPF is Can prevent excessive accumulation of

Similarly, when an external EGR is used, the oxygen concentration of the exhaust gas entering the exhaust gas purification device is reduced, which works to suppress the regeneration of DPF. Therefore, by opening the intake throttle 24 for a short time after a certain interval (after the first predetermined time), the effect of the EGR itself is reduced at that moment, but the second predetermined time has elapsed. The function of EGR will be restored soon afterward. Inside the DPF, the oxygen concentration inside is temporarily reduced, so the function of burning the PM trapped and accumulated in the DPF and continuously regenerating the DPF is significantly promoted. Since D PF is continuously regenerated in this manner, it is possible to prevent excessive accumulation of PM in D PF.

In the exhaust purification system of a diesel engine, the exhaust flow is processed into the mD PF 40, which processes a large amount of exhaust discharged at high load, and the μ DPF 30, which processes a small amount of exhaust discharged at low load of the diesel engine. Even when the switching valve 28 is used to switch the path, as shown in Fig. 10, while using the mD PF 40, throttle the ITP (intake throttle 24) to about 10%. Area exists. If this mD PF 40 is used while the intake flow rate is being restricted, PM may be deposited in the m DPF 40 as in the case where the DPF 30 is used.

As described above, even when control is performed to output control commands for the intake flow control valve such as the switching valve 28 and the intake throttle 24 according to the depression amount of the accelerator pedal and the engine speed, the control means 20 After the first predetermined time measured by the first timer, a control command for expanding the intake flow rate is output to the intake flow control valve such as the intake throttle 24 and the second predetermined time measured by the second timer. By outputting a control command to return the intake flow rate to the original intake flow rate to the intake flow control valve such as the intake throttle 24 etc. after lapse of time, the PM trapped and accumulated in ^ DPFSO or mD PF 40 oxidizes (burns) . Therefore, the function of continuously regenerating the WDPF 30 or mD PF 40 is significantly promoted, and it is possible to prevent excessive accumulation of PM in the μ DPF 30 or mD PF 40. .

As described above, the first predetermined time measured by the first timer is more preferably 9 minutes and 30 seconds to 30 minutes, but from the experience, even if it is 3 minutes to 30 minutes, the present invention It is possible to achieve the purpose.

Further, as described above, the second predetermined time measured by the second timer is preferably 1 second to 60 seconds, but empirically, the present invention of the present invention can be performed even if it is 0.5 seconds to 120 seconds. It is possible to achieve the purpose.

In the figure, the first timer T l, the second timer Τ 2, the third timer 1 Τ 3, and the fourth timer Τ 4 states (H i or L 力 power and diesel engine The figure shows how the intake flow rate of H changes according to the time of day.

Since the setting method and reading method of the first and second predetermined times shown in the figure are the same as the method described in FIG. 12, they are omitted, and the setting methods of the third and fourth predetermined times are omitted. The intake flow rate of the intake throttle 24, etc. based on the fourth predetermined time A method of operating the control valve will be described.

As shown in the figure, the information processing means 280 starts the measurement of the third predetermined time with the start of the measurement of the second predetermined time as well as the function of the calendar clock 2 90 (the third timer T3). To include). Then, the information processing means 280 has acquired, via the bus 2 9 9, information that the calendar clock 2 9 0 (third timer) has measured the passage of the third predetermined time (t 3). In this case, the information processing means 2 8 0 instructs the calendar clock 2 9 0 (including the function of the fourth timer T 4) to start the measurement of the fourth predetermined time (t 4), and A control command to increase the intake flow rate is output to the intake flow rate adjustment valve such as the intake throttle 24 or the like. Then, the information processing means 280 outputs a command to reset the third predetermined time (t 3) to the calendar clock 2 90 (third timer), and a new third predetermined time is again set. Instruct to start measurement.

When the information processing means 2 8 0 acquires the information that the calendar clock 2 9 0 (the fourth timer) has measured the lapse of the fourth predetermined time (t 4) through the bus 2 9 9 In the fourth predetermined time period t4 after the timer 4 has measured, the intake flow rate is set to the original intake flow rate (the original intake flow rate before the start of the new air spike start) for the intake flow control valve such as the intake throttle 24 Output control command to return to). Then, the information processing means 280 outputs a command to reset the fourth predetermined time (t 4) to the calendar clock 2 90 (fourth timer), and the next measurement of the fourth predetermined time is performed. Prepare for. Then, when the information indicating that the calendar timer 2 9 0 (third timer) has measured the lapse of the third predetermined time (t 3) again is acquired via the bus 2 9 9, the information processing is performed. Means 2 8 0 repeatedly performs the same open / close operation of the intake throttle 24 and the like before the elapse of the second predetermined time measured by the second timer.

Therefore, the control means 20 receives the third predetermined time after the first predetermined time measured by the first timer and before the second predetermined time measured by the second timer. After the lapse of the third predetermined time which has been measured, a control command for increasing the intake flow rate is outputted to the intake flow control valve such as the intake throttle 24 etc. After the fourth predetermined time which the fourth timer measures, the intake throttle 2 4 Intake flow such as 12476

35 Output a control command to return the intake flow rate to the original intake flow rate to the volume adjustment valve.

In the same figure, the control means 20 is after the lapse of a predetermined interval (after the first predetermined time t 1) and the differential pressure before and after the DPF may be a predetermined threshold (a constant number). If it is determined that the variable Pt is equal to or greater than the variable Pt, a control command to increase the intake flow rate is output to the intake flow control valve such as the intake throttle 24 etc., and the diesel engine is intermittently An example is shown in which control is performed to increase the intake flow rate of the engine.

ΔΡ shown in the figure is a value based on the pressure difference of the exhaust gas around D P F 30 or m D P F 40 detected by the differential pressure sensor 33 or the differential pressure sensor 43. Also, P shown in the same figure is a threshold for judging that PM has been deposited on / x D P F 30 or m D P F 40 based on ΔP. The threshold P t is the opening degree of the intake flow control valve such as the intake throttle 24 or the engine speed, the displacement of the diesel engine, the volumetric efficiency of the diesel engine, the fuel supply amount, the exhaust density, the exhaust gas constant, It may be a variable that varies based on the pressure loss coefficient of the DPF, the effective cross section of the DPF, the exhaust temperature, etc., or may be set as a constant under predetermined conditions. Details of the method of calculating this Pt will be described later.

In the embodiment shown in the figure, the information processing means 2 8 0 accesses the A-D converter 2 6 0 or IZO 2 7 6 at predetermined sampling time intervals, and differential pressure sensors 3 3, 4 3 etc. It is possible to monitor the pressure difference detected by the sensor and the condition of various sensors. The information processing means 2 8 0 sets the flag P u when it is determined that the pressure difference detected by the differential pressure sensors 3 3 and 4 3 is equal to or more than the predetermined threshold P t (set P u = 1 Then, it is possible to carry out processing to hold the value in the memory 2 8 1 until the next sampling. The calendar clock 2 90 (including the function of the first timer) measures the lapse of the first predetermined time (t 1) based on the instruction of the information processing means 2 8 0. Information processing means 2 8 0 at time t 1 1, power render clock 2 9 0 (first 2003/012476

If the information indicating that the 36 timers T l) has measured the lapse of the first predetermined time (t 1) is acquired via the bus 2 9 9, the information processing means 280 sets the T 1 flag. At the same time (set T 1 = 1 and record in memory 2 8 1), read the flag of P u from memory 28 1 and calculate the logical sum (T l AND P u) of the flags of T 1 and P u Do. If the logical sum of T 1 and P u is 0 (T l AND P u = 0), the pressure difference between the exhaust before and after DP F is within the normal operation range, so fresh air spikes are performed. The control for maintaining the original intake flow rate is performed without outputting an operation command for opening the intake flow control valve such as the intake throttle 24 and the like.

Next, when the information processing means 280 carries out sampling at a time 亥 1j t 1 2, it is determined that the pressure difference detected by the differential pressure sensors 3 3, 4 3 etc. is equal to or more than a predetermined threshold P t Sets the flag P u (set P u = l and record in memory 2 8 1). Then, the information processing means 280 reads out the flag of T 1 and the flag of P u from the memory 281 and calculates the logical sum (T 1 AND P u) of the flags of T 1 and P u. When the logical sum of T 1 and P u is 1 (T 1 AND P u = 1), the information processing means 280 makes a second predetermined time with respect to the calendar clock 2 90 (second timer). While instructing the start of measurement of (t 2), the control command to increase the intake flow rate is output to the intake flow control valve such as the intake throttle 24 and the like. Then, the information processing means 280 outputs a command to reset the calendar clock 2 90 (the first timer) and the logical sum (T l AND P u) of the flags of T 1 and P u, and the new first The start of measurement of the predetermined time of

Next, the calendar clock 29 0 (including the function of the second timer) measures the elapse of the second predetermined time (t 2) based on the instruction of the information processing means 280. The information processing means 280 at time t 13 indicates that the calendar clock 2 90 (second timer) has measured the elapse of the second predetermined time (t 2) through the path 2 9 9 If acquired (after the second predetermined time measured by the second timer has elapsed), the intake flow rate is adjusted to the original intake flow rate for the intake flow control valve such as the intake throttle 24 etc. Control finger to return to the intake flow rate) Output the command. Then, the information processing means 280 outputs a command to reset the second predetermined time (t 2) to the calendar clock 290 (second timer), and for the next measurement of the second predetermined time. Prepare.

Next, when the information processing means 280 has performed sampling at time t 14, if it is determined that the pressure difference detected by the differential pressure sensors 3 3, 4 3 etc. is equal to or more than a predetermined threshold value Pt, Set the flag P u (set P u = 1 and store in memory 28 1). Then, the information processing means 280 reads out the flag of T 1 and the flag of P u from the memory 281 and calculates the logical sum (T 1 AND P u) of the flags of T 1 and P u. At time t14, the flag of T1 is 0 because the first timer has not yet measured the lapse of the first predetermined time. Therefore, since the logical sum of T 1 and P u is 0 (T 1 AND P u = 0), an operation command for opening the intake flow control valve such as the intake throttle 24 for performing fresh air spikes is not output. Perform control to maintain the original intake flow rate.

Next, the information processing means 280 obtains information at the time t 15 that the force rendering clock 290 (first timer) has measured the lapse of the first predetermined time (t 1) through the pass 2 99 In this case, the information processing means 280 sets the flag of T 1 (set it to T 1 = 1 and records it in the memory 2 8 1) and reads the flag of P u from the memory 28 1 Calculates the disjunction of the T 1 and P u flags (T 1 AND P u). When the logical sum of T 1 and P u is 1 (T 1 AND P u = 1), the information processing means 280 makes a second predetermined time with respect to the force render clock 2 90 (second timer). While instructing the start of measurement of (t 2), the control command for increasing the intake flow rate is output to the intake flow control valve such as the intake throttle 24. Then, the information processing means 280 outputs a command to reset the logical sum (T l AND P u) of the force rendering clock 2 90 (the first timer) and the flags of T 1 and P u, The start of measurement of the predetermined time of 1 is instructed.

Next, the calendar clock 2 90 (including the function of the second timer) measures the elapse of the second predetermined time (t 2) based on the instruction of the information processing means 280. Ru. At time t 1 6, the information processing means 2 80 has a bus 2 9 9 as information that the calendar clock 2 9 0 (second timer) has measured the lapse of the second predetermined time (t 2). If it is acquired through the second predetermined time period measured by the second timer, the intake flow rate is adjusted to the original intake flow rate to the intake flow control valve such as the intake throttle 24 (before the start of the new air spike) Output a control command to restore the original intake flow rate of Then, the information processing means 280 outputs a command to reset the second predetermined time (t 2) to the calendar clock 2 90 (second timer), and measures the next second predetermined time. Prepare for the

In this way, in the diesel engine that oxidizes the PM accumulated in the DPF, if the intake throttle 24 etc. is throttled to maintain the exhaust temperature at low load above the specified temperature, Based on the time interval between exhaust and the differential pressure of exhaust air before and after the DPF, the control of opening the intake flow control valve such as the intake throttle 24 etc. for a short time is performed intermittently, only when PM deposits in the DPF. It is possible to inhale more oxygen than the amount of oxygen necessary for the combustion of the fuel, and promote various reactions of oxidation of PM (carbon) deposited in the DPF, convert PM into carbon dioxide and release it to the atmosphere. It will be possible.

Further, in the present invention, the differential pressure of exhaust before and after DPF is monitored, and the amount of oxygen necessary for the combustion of diesel engine is increased only when the differential pressure of exhaust before and after DPF is equal to or greater than a predetermined threshold. Since oxygen was inhaled, frequent fresh air spikes were prohibited to prevent the exhaust temperature from decreasing due to an increase in fresh air intake, and keep the DPF reaction temperature low while suppressing the generation of NOx. It becomes possible to oxidize PM effectively.

In addition, various reactions of PM oxidation are promoted even when internal EGR and external EGR are provided to raise the exhaust temperature at low load and to increase the exhaust temperature at low load by reducing the intake throttle 24. The PM (carbon) deposited in the DPF is oxidized and released to the atmosphere.

Even when the differential pressure of exhaust before and after the DPF is detected and the flow rate of fresh air is intermittently increased based on the differential pressure, the third timer as shown in FIG. 13 is used. It is possible to control the intake flow control valve using the timer and the fourth timer.

In addition, the exhaust flow path is switched between m DPF 40, which processes a large amount of exhaust gas discharged when the diesel engine is heavily loaded, and μ DPF 30, which processes a small amount of exhaust gas discharged when the diesel engine is lightly loaded. Even when the switching valve 28 is provided, it is possible to detect the pressure difference between the exhaust gas before and after the DPF and intermittently increase the flow rate of fresh air based on this pressure difference. Also in this case, frequent fresh air spikes are prohibited to prevent the decrease in exhaust temperature due to the increase in the amount of fresh air inhaled, while suppressing the generation of NOx / DPF 30 and m DPF 40 reaction It is possible to maintain the temperature and oxidize PM effectively.

In the above description, as a timer for measuring a predetermined time, an example of a timer that counts the count is shown, but the timer that can be used in the present invention is not limited to the timer of the above-mentioned type, Other electrical timers may be used, such as measuring the amount of charge reduction, or it is possible to achieve the object of the present invention by using a mechanical timer using a dashpot or the like.

The method of calculating the pressure loss calculation value ΔP c for calculating the threshold P t of the pressure difference ΔΡ before and after the detected D P F will be described below.

The relationship between the pressure difference ΔP c between the exhaust gas and the exhaust gas flow rate before and after D P F is generally recognized as the relationship shown in the following (Equation 2).

^ = -fexv ² ) ... (Expression 2)

p ex 2

However,

Δ Ρ ο D: Pressure difference (exhaust pressure) of exhaust gas around D P F

ex: Density of exhaust gas (kg / m ³ )

Pressure loss factor

V: Exhaust flow velocity (m / s)

Note that the density of exhaust gas; 0 ex can be expressed by the following (Expression 3). p ex = ... (Equation 3)

RXT

However,

P: Gas pressure of exhaust (absolute value) (kPa)

R: Exhaust gas constant 287.03 (J / (kg · K))

T: Exhaust temperature (absolute value) (K)

Here, the flow velocity V (m / s) of the exhaust can be expressed as (Equation 4) below.

Q

V =-

A

=-Xi ... (Equation 4)

p ex A

However,

Q: Volumetric flow of exhaust ³ / s)

A: Effective sectional area in the DPF (m ³ )

G: Mass flow rate of exhaust (kg / s)

Also, the mass flow rate G of the gas can be schematically represented by the following (Equation 5). In other words, the fuel injection flow rate can be neglected in the first place compared to the amount of intake air. If this can not be ignored, Gf can be added to G in (Eq. 5) with the fuel injection flow rate as G f (kg / s).

_{G =} (NexVh) _{x vx χ 1 0-3} ... (Equation ₅₎ However,

Mass flow rate of exhaust gas (kg / s)

N e Engine speed (rpm)

V h Total displacement of engine (L)

η 体積 volumetric efficiency

in Density of intake air (kg / m ³ )

The above 7 v and / 0 in are values calculated based on the temperature and pressure of the in-take mar-hold.

Therefore, substituting (Expression 4) into (Expression 2), the following (Expression 6) Is obtained.

-(Expression 6)

Next, transforming the above (equation 6) and calculating APc,

... (equation 7)

It becomes.

Here, assuming that the pressure loss coefficient is constant in any region of mass flow rate G, the term including the effective cross-sectional area Α in the DPF can be a constant. 8) It can be expressed as

[G

APc— Const. X (equation 8)

p ex

If the pressure difference calculated value APc of the exhaust calculated by the above (Equation 8) and G ² / p ex obtained by dividing the square of the mass flow rate of the exhaust by the density are respectively shown on the vertical axis and the horizontal axis, Resistance characteristics are obtained.

The above (Eq. 8) can be said to be a continuous equation including the terms of temperature and pressure. Even if the temperature and pressure conditions change, such as the intake system and exhaust system of a diesel engine, the characteristics of the throttling element system can be uniquely expressed if plotted on this characteristic.

Therefore, if the temperature and pressure of air in the intake manifold 12, and the DPF inlet temperature and pressure, and the DPF outlet pressure are measured, using the above-mentioned calculation formula, the engine operating condition at that time can be obtained. The calculated pressure difference ΔPc before and after DPF can be calculated. Then, by comparing the threshold value Pt based on the calculated value ΔPc of the pressure difference with the pressure difference ΔP before and after the actually detected DPF, the condition for performing the fresh air spike (limit of PM deposition) is determined. It becomes possible to judge.

FIG. 15 is a diagram showing the relationship between the pressure difference calculated value Δ Pc before and after D P F and the allowable pressure difference P t at that time.

In the figure, the calculated value of the pressure difference before and after the initial DPF of the exhaust gas purification system It is indicated by a solid line, and the allowable pressure differential pressure P t at the limit of PM deposition is indicated by a broken line. According to the present invention, as shown in the figure, PM deposits inside the DPF, and if it deposits further, rapid combustion occurs at the time of regeneration, and the pressure difference threshold at the limit that may cause PM carrier to burn out. It becomes possible to set as an allowable pressure difference Pt.

For a pressure difference calculated value Δ P 0 (a value of AP c calculated by substituting a predetermined exhaust gas density p ex, an exhaust gas mass flow rate G and a constant into equation 8) in a predetermined operating condition of a diesel engine Pressure difference before and after DPF actually detected

If ΔP is smaller than the allowable pressure difference Pt, it is determined that the normal operation range is established, and the control of the fresh air spike is not performed and the normal operation is maintained. If the detected pressure difference Δ 差 before and after D P F is a pressure difference greater than or equal to the allowable pressure difference P t, control of the fresh air spike is performed on the condition that the first predetermined time has elapsed.

Based on the pressure differences Δ P and P t actually detected, the conditions for determining whether or not to perform the fresh air spike are as follows.

P When P <Pt: No new air spike control is performed

P When P P P t: Perform fresh air spike control

As shown in FIG. 15 and (Expression 8) above, the threshold value of the allowable pressure difference P t can be determined according to the square of the mass flow rate G of the exhaust of the diesel engine. Also, the threshold value of the allowable pressure difference Pt can be determined according to the value obtained by dividing the square of the mass flow rate G of the exhaust of the diesel engine by the density of the exhaust; 0 ex. Industrial Applicability The present invention relates to a PM oxidizer in a diesel engine, which purifies exhaust gas by oxidizing particulate matter (PM) contained in exhaust gas of diesel engine deposited in a diesel particulate filter. An intake flow control valve for adjusting the intake flow rate of the diesel engine; A first timer for measuring the passage of a first predetermined time, a second timer for measuring the passage of a second predetermined time, and the intake flow rate after the first predetermined time measured by the first timer has elapsed A control command to increase the intake flow rate is output to the control valve, and a control command to return the intake flow rate to the original intake flow rate is output to the intake flow control valve after the second predetermined time measured by the second timer has elapsed. And control means for

According to the present invention, since the new flow rate is intermittently increased to temporarily supply an excess amount of oxygen and nitrogen oxides to the DPF, it is possible to suppress the generation of NOx and maintain the reaction temperature of the DPF. It is possible to oxidize PM. And, it is possible to prevent the problem that PM accumulates excessively in DPF.

Further, according to the present invention, the first timer can be used even in the case where the existing diesel engine exhaust gas purification system is used and there is a defect that PM is gradually accumulated in the DPF. The control command for increasing the intake flow rate is output to the intake flow rate control valve after the first predetermined time measured by the timer, and the intake flow rate is originally output to the intake flow rate control valve after the second predetermined time measured by the second timer. By subsequently adding control means or the like for outputting a control command for returning to the intake flow rate, it becomes possible to effectively oxidize PM deposited in the DPF to purify the exhaust and continuously regenerate the DPF. . According to the present invention, in the PM oxidizer of a diesel engine, an exhaust cam having an exhaust valve timing for returning exhaust to a cylinder before combustion, an intake flow control valve for adjusting an intake flow rate, a first timer, And a control means for outputting a control command to the intake flow control valve after an elapse of a predetermined time measured by each of the first timer and the second timer.

According to the present invention, in the PM oxidizer in a diesel engine, an EGR means for controlling an exhaust gas recirculation amount, an intake flow rate control valve for adjusting an intake flow rate, a first timer, a second timer, and After the predetermined time measured by each of the second timer and the second timer has elapsed. And control means for outputting a control command.

According to the present invention, even when the exhaust gas temperature is increased at low diesel engine load using internal EGR or external EGR, the flow rate of fresh air is momentarily increased to temporarily Since excess oxygen and nitrogen oxides are supplied to the DPF, PM can be effectively oxidized while suppressing the generation of NOx and maintaining the reaction temperature of the DPF. And, it becomes possible to prevent the problem that PM accumulates excessively in DPF.

The present invention relates to a PM oxidation apparatus in a diesel engine, comprising: a switching valve that switches an exhaust flow path between a main DPF and a micro DPF; an intake flow control valve that controls an intake flow; a first timer; The timer, The control valve of the switching valve and the intake flow control valve is output according to the depression amount of the accelerator pedal and the engine speed, and the above-mentioned after the predetermined time measured by each of the first timer and the second timer elapses. And a control means for outputting a control command to the intake flow control valve.

According to the present invention, even when the exhaust path is switched between the μ DPF and the m DPF using the switching valve, the flow rate of fresh air is intermittently increased to temporarily increase the μ DPF or Since oxygen and nitrogen oxides are supplied in excess to the m DPF, it is possible to effectively oxidize PM while suppressing the generation of NO x and maintaining the reaction temperature of the DPF. And, it becomes possible to prevent the problem of excessive accumulation of PM in / z DP F or m DP F.

Further, according to the present invention, in a PM oxidizer in a diesel engine, an intake flow control valve for adjusting an intake flow rate, a first timer, a second timer, and a differential pressure sensor for detecting a pressure difference before and after the DPF. After the elapse of a first predetermined time measured by the first timer and the pressure difference detected by the differential pressure sensor is equal to or greater than a predetermined threshold value, the intake flow rate is adjusted to the intake flow rate adjustment valve. Output a control command to increase the flow rate, and after the second predetermined time measured by the second timer has passed, the Control means for outputting a control command for returning to the intake air flow rate of

According to the present invention, the differential pressure of exhaust before and after DPF is monitored, and the amount of oxygen necessary for the combustion of diesel engine is exceeded only when the differential pressure of exhaust before and after DPF is equal to or greater than a predetermined threshold. Since a large amount of oxygen was inhaled, frequent fresh air spikes were prohibited to prevent the exhaust temperature from decreasing due to an increase in the amount of fresh air intake, and maintain the reaction temperature of the DPF while suppressing the generation of NOx. It is possible to effectively oxidize PM.

Claims

The scope of the claims

1. A PM oxidation method in which exhaust gas emitted from a diesel engine is oxidized through PM (particulate matter) in exhaust gas through an exhaust purification device, and an intake air throttle 2 in the intake passage of the diesel engine 2 4 to increase the exhaust temperature of exhaust gas flowing from the diesel engine to the exhaust purification device, and to periodically open the intake throttle 24 to supply fresh air to the diesel engine. Oxidation method.

2. In the PM oxidation method according to claim 1, in order to increase the exhaust temperature of the exhaust gas flowing from the diesel engine into the exhaust purification device, the exhaust gas is generated near the bottom dead center of the intake stroke of the diesel engine. A PM oxidation method characterized by performing exhaust gas recirculation by flowing back into a cylinder of the diesel engine in which high temperature exhaust gas is depressurized by opening a pulp.

3. The PM oxidation method according to claim 1 or 2, wherein the exhaust gas purification device is any one continuously regenerating DPF selected from DOC and DPF, DOC and catalyst supported DPF, and catalyst supported DPF. PM oxidation method characterized in that

4. In the PM oxidation method according to claim 1, the exhaust gas purification device is composed of a main exhaust gas purification device and an auxiliary exhaust gas purification device, and the exhaust port of the diesel engine and the main exhaust gas purification device The main exhaust pipe is connected by an auxiliary exhaust pipe, and the auxiliary exhaust pipe is provided with both ends connected to the main exhaust pipe, and the auxiliary exhaust pipe is connected with the auxiliary exhaust purification device. In other words, when the small exhaust flow rate at low load of the diesel engine, the switching valve provided on the main exhaust pipe is closed so that the total flow of exhaust gas from the diesel engine passes through the auxiliary exhaust pipe. And the switching valve is opened when the flow rate of exhaust gas is increased when the diesel engine is under high load.

5. The PM oxidation method according to claim 2, wherein the exhaust gas purification device A main exhaust purification device and an auxiliary exhaust purification device are provided, and the exhaust port of the diesel engine and the main exhaust purification device are connected by a main exhaust pipe, and the auxiliary exhaust pipe is connected to both ends of the main exhaust pipe. The auxiliary exhaust pipe is connected to the auxiliary exhaust pipe, and the auxiliary exhaust gas purification device is connected to the auxiliary exhaust pipe. When the small exhaust flow rate of the diesel engine at low load, the auxiliary exhaust pipe is connected to the main exhaust pipe. By closing the switching valve, the entire flow rate of exhaust gas from the diesel engine is sent to the auxiliary exhaust purification device through the auxiliary exhaust pipe, and the diesel engine is loaded at high load. The PM oxidation method characterized in that the switching valve is opened when the exhaust flow rate is increased.

6. In the PM oxidation method according to claim 4 or 5, the main exhaust gas purification device is any one selected from DOC and DPF, DOC and catalyst supported DPF, and catalyst supported DPF. The auxiliary exhaust gas purification apparatus is any one continuous regeneration type DPF selected from DOC, DPF, DOC, catalyst supported DPF, and catalyst supported DPF. PM oxidation method.

7. Particulate matter (PM) contained in the exhaust of the diesel engine accumulated in the diesel particulates, the finoreta is oxidized to purify the exhaust, and in the PM oxidizer in the diesel engine, the intake flow rate of the diesel engine is adjusted An intake flow rate control valve; a first timer that measures a lapse of a first predetermined time;

A second timer that measures the elapse of a second predetermined time;

After a first predetermined time measured by the first timer, a control command to increase the intake flow rate is outputted to the intake flow rate adjustment valve, and after a second predetermined time measured by the second timer, Control means for outputting a control command for returning the intake flow to the original intake flow to the intake flow control valve;

PM oxidation equipment in a diesel engine characterized by

8. Diesel 'particulates' Diesel deposited in the filter In a PM oxidizer in a diesel engine that oxidizes particulate matter (PM) contained in the exhaust of the engine to purify the exhaust, the exhaust valve is opened near the end of the intake stroke of the engine to exhaust the exhaust into the cylinder before combustion. An exhaust cam with exhaust valve timing to return;

An intake flow control valve that adjusts an intake flow rate of a diesel engine; a first timer that measures an elapse of a first predetermined time;

A second timer that measures the elapse of a second predetermined time;

After a first predetermined time measured by the first timer, a control command for increasing the intake flow rate is output to the intake flow rate adjustment valve, and after a second predetermined time measured by the second timer, Control means for outputting a control command for returning the intake flow to the original intake flow to the intake flow control valve;

PM oxidation equipment in a diesel engine characterized by

9. PM particulate oxidation apparatus in a diesel engine, which purifies exhaust gas by oxidizing particulate matter (PM) contained in the exhaust of the diesel engine deposited in the diesel particulate filter (DPF)

Two types of DPF that collect and process particulate matter contained in exhaust of diesel engine, which is a main DPF that processes a large amount of exhaust when the diesel engine is heavily loaded, and low load of diesel engine A micro DPF that processes a small amount of exhaust gas that is discharged from time to time;

A second timer that measures the elapse of a second predetermined time;

The control command for the switching valve and the intake flow control valve is output according to the depression amount of the accelerator pedal and the engine speed, and the intake flow control valve is operated after the first predetermined time measured by the first timer. The control command that increases the intake flow rate is output, and the second timer measured by the second timer Control means for outputting a control command to return the intake flow rate to the original intake flow rate to the intake flow rate adjustment valve after a predetermined time has elapsed;

PM oxidation equipment in a diesel engine characterized by

1 0. Diesel PM 's in PM engine oxidizer in diesel engine, which oxidizes particulate matter (PM) contained in diesel engine's exhaust accumulated in diesel' particulate 'filter.

E G R means for controlling the amount of exhaust recirculation when recirculating the exhaust to the intake side;

A second timer that measures the elapse of a second predetermined time;

PM oxidation equipment in a diesel engine characterized by

1 1. Diesel 'particulate' In PM oxidator in diesel engine, the particulate matter (PM) contained in the exhaust of diesel engine accumulated in the finoreta is oxidized to purify the exhaust,

A second timer that measures the elapse of a second predetermined time;

A differential pressure sensor that detects a pressure difference around the D P F;

After the elapse of a first predetermined time measured by the first timer and the pressure difference detected by the differential pressure sensor is equal to or greater than a predetermined threshold value, Control command to increase the intake flow rate is output to the intake flow rate control valve, and control is performed to return the intake flow rate to the original intake flow rate to the intake flow rate control valve after a second predetermined time measured by the second timer. Control means for outputting a command;

PM oxidation equipment in a diesel engine characterized by

1 2. PM P oxidizer in diesel engine which purifies exhaust gas by oxidizing particulate matter (P M) contained in exhaust of diesel engine accumulated in diesel particulate finoreta.

An exhaust cam having an exhaust valve timing that opens the exhaust valve near the end of the intake stroke of the engine and returns the exhaust to the cylinder before combustion, an intake flow control valve that adjusts the intake flow rate of the diesel engine, and a first predetermined time A first timer that measures the progress of

A second timer that measures the elapse of a second predetermined time;

After the elapse of the first predetermined time measured by the first timer, and the pressure difference detected by the differential pressure sensor is equal to or greater than a predetermined threshold, the intake flow control valve Control means for outputting an increasing control command and outputting a control command for returning the intake flow rate to the original intake flow rate to the intake flow control valve after the second predetermined time measured by the second timer has elapsed.

PM oxidation equipment in a diesel engine characterized by

1 3. In PM oxidizer for diesel engine, the particulate matter (PM) contained in the exhaust of diesel engine deposited in diesel 'particulate filter (DPF) is oxidized to purify the exhaust,

Capture particulate matter contained in diesel engine exhaust Two types of DPFs that are collected and processed: a main DPF that processes a large amount of exhaust emitted when the diesel engine is heavily loaded, and a micro that processes a small amount of exhaust discharged when the diesel engine is lightly loaded Switching valve for switching the exhaust flow path to DPF, and

A second timer that measures the elapse of a second predetermined time;

A control command for the switching valve and the intake flow control valve is output according to the depression amount of the accelerator pedal and the engine speed, and after the first predetermined time measured by the first timer has elapsed, the differential pressure When the pressure difference detected by the sensor is equal to or greater than a predetermined threshold value, a control command for increasing the intake flow rate is output to the intake flow rate control valve, and a second predetermined time elapsed by the second timer is elapsed. Control means for later outputting a control command for returning the intake flow rate to the original intake flow rate to the intake flow rate adjustment valve;

PM oxidation equipment in a diesel engine characterized by

1 4. Particulate matter (P M) contained in the exhaust of diesel engine deposited in the diesel particulate filter The particulate matter (P M) in the diesel engine is oxidized to purify the exhaust gas.

A second timer that measures the elapse of a second predetermined time;

After the elapse of a first predetermined time measured by the first timer and the pressure difference detected by the differential pressure sensor is equal to or greater than a predetermined threshold value, The control command for increasing the intake flow rate is output to the intake flow rate control valve, and the intake flow rate control valve is returned to the original intake flow rate after the second predetermined time measured by the second timer has elapsed. Control means for outputting a command;

PM oxidation equipment in a diesel engine characterized by

In the PM oxidation apparatus in the diesel engine of claims 7 to 10

A third timer that measures the elapse of a third predetermined time;

And a fourth timer for measuring the elapse of a fourth predetermined time,

After the elapse of a first predetermined time measured by the first timer and before the elapse of a second predetermined time measured by the second timer,

After a third predetermined time measured by the third timer, a control command for increasing the intake flow rate is outputted to the intake flow rate adjustment valve, and after a fourth predetermined time measured by the fourth timer, Control means for outputting a control command for returning the intake flow to the original intake flow to the intake flow control valve;

PM oxidation equipment in a diesel engine characterized by

A PM oxidizer in a diesel engine according to any one of claims 1 to 14

A third timer that measures the elapse of a third predetermined time;

A fourth timer measuring elapsed time of a fourth predetermined time;

And a differential pressure sensor for detecting a pressure difference around the DPF,

A second predetermined value measured after the first predetermined time measured by the first timer has elapsed and the pressure difference detected by the differential pressure sensor is equal to or greater than a predetermined threshold value. Before the lapse of time, a control command for increasing the intake flow rate is outputted to the intake flow control valve after the lapse of a third predetermined time measured by the third timer, and the fourth timer measures the fourth After the predetermined time has passed, the intake flow control valve Control means for outputting a control command for returning to the air flow rate;

PM oxidation equipment in a diesel engine characterized by

In the PM oxidizer of a diesel engine according to any one of claims 7 to 14,

The PM oxidizer in a diesel engine, wherein the first predetermined time measured by the first timer is a time between 3 minutes and 30 minutes.

In the PM oxidation apparatus of a diesel engine according to any one of claims 7 to 14,

The PM oxidizer in a diesel engine, wherein the second predetermined time measured by the second timer is a time between 0.5 second and 120 seconds.

The PM oxidizer in the diesel engine according to claims 1 to 14

The PM oxidizer in a diesel engine, wherein the predetermined threshold is a threshold determined according to a square of a mass flow rate of exhaust of a diesel engine.

In the PM oxidizer in the diesel engine according to claims 1 to 14,

The PM oxidizer in a diesel engine characterized in that the predetermined threshold is a threshold determined according to a value obtained by dividing the square of the mass flow rate of exhaust of a diesel engine by the density of exhaust.

2 1. The intake flow control valve that adjusts the intake flow rate of the diesel engine, the first timer that measures the lapse of the first predetermined time, and the second timer that measures the lapse of the second predetermined time, Control means for outputting a control command for adjusting the opening degree of the intake flow control valve based on the first predetermined time measured by the first timer and the second predetermined time measured by the second timer; Control unit of PM oxidation system in A PM oxidation program for a diesel engine, comprising purifying particulate matter (PM) contained in exhaust gas of a diesel engine deposited in a diesel particulate filter, the control means comprising:

A function of reading out information that has passed a first predetermined time measured by the first timer;

A function of outputting a control command to increase the intake flow rate to the intake flow control valve after a first predetermined time measured by the first timer has elapsed;

A function of reading out information that has passed a second predetermined time measured by the second timer;

Outputting a control command for returning the intake flow rate to the original intake flow rate to the intake flow rate adjustment valve after a second predetermined time measured by the second timer has elapsed.

A PM oxidation program that is characterized by realizing

2 2. The PM of the diesel engine according to claim 1, further comprising a third timer for measuring the passage of a third predetermined time, and a fourth timer for measuring the passage of a fourth predetermined time. A PM oxidation program operated by control means of the oxidizer,

In the control means,

A third time measured by the third timer after a first predetermined time measured by the first timer and before a second predetermined time measured by the second timer. The control command for increasing the intake flow rate is outputted to the intake flow control valve after a predetermined time has elapsed, and the intake flow rate is originally transmitted to the intake flow control valve after a fourth predetermined time measured by the fourth timer. A PM oxidation program characterized by realizing a function of outputting a control command to return to the intake flow rate.

2 3. An intake flow control valve that adjusts the intake flow rate of the diesel engine, a first timer that measures the lapse of a first predetermined time, and a second timer that measures the lapse of a second predetermined time, Capture PM (particulate matter) A differential pressure sensor for detecting a pressure difference before and after the DPF, a first predetermined time measured by the first timer, a second predetermined time measured by the second timer, and a differential pressure sensor The control unit of the PM 5 oxidation engine in the diesel 5 'engine has control means for controlling the opening of the intake flow control valve based on the pressure difference, and operates with the control means of the PM oxidizer in the diesel 5' engine. · A PM oxidation program in a diesel engine that purifies exhaust gas by oxidizing particulate matter (PM) contained in the exhaust of the diesel engine accumulated in the filter,

In the control means,

0 A function of acquiring a pressure difference before and after D P F detected by the differential pressure sensor, and a function of reading out information that has elapsed for a first predetermined time measured by the first timer,

After the elapse of a first predetermined time measured by the first timer and the pressure difference detected by the differential pressure sensor is equal to or greater than a predetermined threshold value, the intake flow rate is applied to the intake flow rate control valve. Function to output control commands that increase

A function of outputting a control command for returning the intake air flow rate to the original intake air flow rate to the intake air flow amount adjustment valve after a second predetermined time measured by the second timer has elapsed;

A PM oxidation program that is characterized by realizing

The diesel engine according to claim 5, further comprising a third timer for measuring the elapse of a third predetermined time, and a fourth timer for measuring the elapse of a fourth predetermined time. A PM oxidation program operated by the control means of the PM oxidation apparatus,

In the control means,

After the elapse of a first predetermined time measured by the first timer, and the pressure difference detected by the differential pressure sensor is greater than or equal to a predetermined threshold Before the second predetermined time measured by the second timer, a control command to increase the intake flow rate is output to the intake flow control valve after the third predetermined time measured by the third timer has elapsed. The fourth timer measures

A function of outputting a control command for returning the intake air flow rate to the original intake air flow rate to the intake air flow rate adjustment valve after the lapse of a predetermined time of 4 is realized.

PM oxidation program.

In the PM oxidation program of the diesel engine according to claim 2 1 or 2 3

The PM oxidation program, wherein the first predetermined time measured by the first timer is a time between 3 minutes and 30 minutes.

In the PM oxidation program of the diesel engine according to claim 21 or claim 23

The PM oxidation program, wherein the second predetermined time measured by the second timer is a time between 0.5 second and 120 seconds.

In the PM oxidation program of the diesel engine according to claim 2 1 or 2 3

The PM oxidation program for a diesel engine, wherein the predetermined threshold value is a threshold value determined according to the square of the mass flow rate of exhaust of the diesel engine.

In the PM oxidation program of the diesel engine according to claim 23 or claim 24

The PM acid program in a diesel engine characterized in that the predetermined threshold value is a threshold value determined according to a value obtained by dividing the square of the mass flow rate of exhaust gas of a diesel engine by the density of exhaust gas.