JPS60224914A - Filter unit for exhaust pressure detection sensor in diesel engine - Google Patents

Abstract

PURPOSE:To make improvements in detection accuracy and durability, by having a water trapping wire mesh and an exhaust pulsation reducing volume built in a filter unit which is used for an exhaust pressure detection sensor to detect loading in a collection member for particulates in exhaust. CONSTITUTION:This filter unit 49a to be installed alongside inside a pipe line taking out pressure at both upstream and downstream sides of a Diesel particulate oxidizer (DPO) interposingly installed in an exhaust passage comprises a casing 49 having an inlet 49c and an outlet 49b on the same axis. And, an exhaust pulsation reducing damping volume 83 with a built-in wire mesh 84, a first step filter 85, a spacer 87 and a second step filter 86 are all set up inside this casing 49 ranging from the inlet 49c to the outlet 49b in regular sequence. With this constitution, aqueous vapor in exhaust is condensable and selectable by means of the wire mesh 84, while exhaust pulsation is reducible owing to the presence of the volume 83, thus detection accuracy in an exhaust pressure sensor is improvable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a filter device for an exhaust pressure detection sensor connected to the exhaust system of a diesel engine.

[Conventional technology]

Diesel engine exhaust contains particulates, which are flammable, fine carbonized compounds, and are the main cause of black smoke in the exhaust gas. These particulates will spontaneously ignite and burn when the vehicle is running at high speed and under high load (hereinafter referred to as "self-combustion") if the particulate temperature reaches S00'C or higher, for example. When the vehicle is running or idling (accounting for more than 90% of the time when the vehicle is in operation), it is directly released into the atmosphere.

However, since particulates may be harmful to the human body, in recent years there has been much research into diesel particulate oxidizers (hereinafter sometimes referred to as rDPOJ), which are installed in the exhaust passage of diesel engines for vehicles. By the way, as this DPO is used, it tends to collect and deposit particulates and block the exhaust passage.
In order to regenerate this DPO, research is currently underway on a mechanism that promotes the re-combustion of particulates.

Such regeneration auxiliary mechanisms include, for example, retarding the fuel injection timing, throttling the intake air, and increasing the amount of exhaust gas recirculation.
It is undesirable to operate the regeneration assist mechanism for a long period of time, as this will worsen the feeling and reduce fuel consumption.

Therefore, in a conventional diesel particulate oxidizer regeneration device, a pressure sensor may be used to detect the exhaust pressure in the upstream exhaust passage of the DPO in order to start or stop the operation of the regeneration assist mechanism. .

[Problem that the invention seeks to solve]

However, such diesel engine exhaust pressure detection sensors are unable to sufficiently reduce exhaust pulsation, and a filter with a built-in sensor alone can reduce water vapor present in the exhaust.

Since soot, SOX, etc. are supplied to the sensor diaphragm, there are problems such as water freezing and soot clogging in the sensor diaphragm, which prevents accurate detection of exhaust pressure and delays transmission. This not only causes deterioration in pressure sensor performance, such as the occurrence of blemishes, but also deterioration in durability.

The present invention aims to solve these problems and makes it possible to sufficiently reduce exhaust pulsation, and also to reliably prevent water vapor, soot, etc. present in the exhaust from entering. An object of the present invention is to provide a filter device for an exhaust pressure detection sensor of a diesel engine.

[Means for solving problems]

Therefore, the filter device for an exhaust pressure detection sensor of a diesel engine of the present invention is a filter device installed in a pipe connecting an exhaust passage of a diesel engine and an exhaust pressure detection sensor. The present invention is characterized in that it includes a filter for collecting soot, and a wire mensch for a water trap and a volume for reducing exhaust pulsation, which are provided on the exhaust passage side of the filter.

[For I]

Pulsations in the exhaust pressure from the exhaust passage are reduced in the exhaust pulsation reducing volume, water vapor in the exhaust is collected in the water trap wire mesh, soot in the exhaust is collected in the filter, and in this way the pulsations in the exhaust pressure are reduced. The exhaust gas is supplied to the exhaust pressure detection sensor.

〔Example〕

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
The figure shows a regeneration device for a diesel particulate oxidizer equipped with a filter device for an exhaust pressure detection sensor of a diesel engine as an embodiment of the present invention. A sectional view and a schematic diagram showing the main body of the device, Fig. 2 is its overall configuration diagram, Fig. 3 is its block diagram, Fig. 4 is a schematic configuration diagram showing the automatic timer of the \°E type timer, and Fig. 5 is Its hydraulic system diagram, Fig. 6 is a configuration diagram showing its collected material barge mechanism, Fig. 7 is a graph showing its operation, and Fig. 8 explains its required advance angle characteristics (required fuel injection timing characteristics). FIG. 9 is a graph showing the relationship between the amount of particulates deposited on the DPO, the main muffler pressure loss and the DPO pressure loss, and FIG. 10 is a graph showing the action of the par:) mechanism.

As shown in Figures 1 to 6, a diesel engine E is equipped with a solenoid timer ST as an on-off valve and a retard valve R.
A distribution type fuel injection pump 17 is provided as a fuel injection timing adjustment means, which has a built-in timer equipped with V.
This diesel engine E has its cylinder block 1
．． The cylinder head 21 has a main chamber formed by a piston (not shown) and an auxiliary chamber (not shown) formed in the cylinder head 2 and communicating with the main chamber.

Further, an intake passage 3 is connected to the main chamber of this diesel engine E via an intake valve (not shown), and
An exhaust passage 4 is connected through an exhaust valve (not shown), and a diesel particulate oxidizer (DP) that captures particulates in the exhaust gas is connected to the exhaust passage 4.
O) S is interposed.

Note that particulates here refer to combustible fine particles mainly composed of carbon and hydrocarbons, with an average diameter of about 0.3 μm and a temperature of about 5 o'clock or more (350 °C or more in the presence of an oxidation catalyst). ) will self-ignite.

In addition, the trap carrier for this DPO5 is a deep trap type heat-resistant ceramic with a catalyst containing platinum, palladium, or ronium inside. In the following, this diesel particulate collection member will be described as described above.
It is abbreviated as DPO (diesel particulate oxidizer).

The D P O 5 communicates with the atmosphere via a muffler 6 and always receives exhaust gas from the engine E via a turbocharger 7 and a heat insulating pipe 8 (when not regenerating).

Exhaust pressure sensors 10 are attached to the inlet and outlet exhaust passages 4 of the DPO 5 through electromagnetic switching valves 78 and 79, respectively, for detecting the exhaust pressure at that position and outputting a detection signal to the ECU 9, which will be described later.

Each of the solenoid valves 78 and 79 includes a regeneration assisting mechanism control means, an on-off valve control means, and a calculation unit 1, which are constituted by a fan computer or the like.
The respective solenoids 78a and 79a receive control signals from the electronic control device (EC1J) 9, which also serves as an operation end detection unit and a purge mechanism control unit, and the valve bodies 78b and 7
By controlling the suction of the valve body 79b, the suction (
DPO5 when the valve body 78b is in the open) state and the valve body 78b is in the protruding (open) state.
The downstream (outlet) exhaust gas pressure P, of the valve body 78b is suctioned (
Open) Status tension valve body? In the protruding (closed) state of 9b, D P
05 upstream (person 1-1) exhaust gas pressure P1 is detected.

Furthermore, an electromagnetic switching valve 77 is provided, and the ECU 9
The solenoid 77a receives a control signal from the valve body 77.
By controlling the suction of the valve body 77b, the valve body 77b is suctioned (opened).
Atmospheric pressure (i.e.,
77 Ra 6 downstream pressure P. pressure equal to ).

The downstream (outlet) exhaust gas or the upstream (inlet) exhaust gas is filtered through a filter device 49a for an exhaust pressure detection sensor installed in the pipe 94.
.

49b to solenoid valves 78 and 79.

Inside the casing 49 consisting of two housings 92 and 93 of the filter devices 49a and 49b are shown in FIG.
As shown in b), a wire mesh 84 extends from the exhaust passage side outlet 49c to the exhaust pressure sensor side outlet 49d.
Built-in damping volume 83° for reducing exhaust pulsation; first stage filter 85. Spacer 87. Second stage filters 86 are arranged in sequence.

Since the wire mesh 84 has the casing 49 disposed away from the exhaust passage 4, it cools and condenses water vapor in the exhaust gas and prevents moisture from entering the sensing iaphragm portion of the pressure sensor 10. It functions as a water trap (steam/water separator).

This wire member 84 is disposed in a space within the casing 49 that forms a damping volume 83 for reducing exhaust pulsation, and the damping volume 83 supplies exhaust gas with reduced exhaust pulsation to filters 85 and 86.

The filters 85 and 86 each include two PVF filter parts 85a and 86a and an AC-26 filter part 85.
b, 86b, and the first stage filter 85 is:
SUS plate 89 and F'RMii! O-ring 8
8 and a PBTB spacer 87, the second stage filter 86 is interposed between the spacer 87 and the FRM! #! O
It is interposed between the ring 88' and the housing 93.

A hole 87a is opened in the center of the spacer 87.

Note that each filter 85. , 86 are set as small as possible to reduce the amount of gas passing through the filter 85.86, and the pressure sensor 10 side volume 91 is connected to the pressure sensor 10 through piping 94. is connected to.

The reason why the pressure sensor 1011I volume 90.91 of each filter 85.86 is set small is based on the following findings.

The amount of gas flowing into this filter 85.86 is caused by exhaust pulsation, and when the exhaust pressure supplied to the filter 85.86 changes from (P - ΔP/2) to (P + ΔP/2), The gas mass JG passing through the filters 85 and 86 is as follows.

ΔG=Gy G−=(,IIP・V)/RTThe volume Δ■ (pressure P, gas temperature 'F) at this time is as follows.

JV-ΔGRT/P=(ΔP・V)/P Therefore, the gas flow rate caused by exhaust pulsation is determined by the pulsation amplitude ΔP and the filter upstream volume (volume from filter 85°86 to sensor diaphragm part) V (sensor dead volume is ignored).

Furthermore, a purge mechanism PM is provided as shown in FIG. 6, and controls switching of compressed air supplied from a compressed air supply means (here, the compressor of the turbocharger 7) 82 using an electromagnetic switching valve 76. The electromagnetic switching valve 76 has ECtJ9 connected to its solenoid 76a.
When the purge mechanism PM is activated, the electromagnetic switching valves 76 and 78 are opened, and the filter 85 and wire mesh 84 of the filter device 49a are opened and closed in response to a control signal from the valve body 76b. Soot and moisture are purged into the exhaust passage 4.

Further, the electromagnetic switching valves 76 and 79 are opened, and soot and moisture are purged from the filter 85 and wire mesh 84 of the filter device 49b to the exhaust passage 4.

In addition, an exhaust passage 4 adjacent to the inlet (upstream) of the DPO 5
A temperature sensor (thermocouple) 14 is provided for detecting the DPO inlet exhaust gas temperature Tin.
The detection signal from is input to the ECU 9.

Furthermore, inside the DPO5, the temperature T'(
In particular, a temperature sensor (thermocouple) 15 is provided to detect the filter bed temperature), and a temperature sensor (thermocouple) 15 is provided to detect the filter bed temperature (
A temperature sensor (thermocouple) 16 for detecting the DPO output temperature To is provided in the exhaust passage 4 adjacent to the downstream), and the detection signals from each of these temperature sensors 1, 5, and 16 are sent to the ECU 9. is input to.

The fuel injection pump 17 attached to the engine E is
The fuel injection timing can be adjusted by the fuel injection timing control means 18, which constitutes the regeneration assisting mechanism control means, which receives the control signal from the CU 9. An injection pump lever opening sensor (load sensor) 19 is attached to this injection pump 17,
Outputs the injection pump lever opening degree to the ECU 9.

Further, an engine speed sensor 20 is provided as an engine state sensor for detecting the speed N of the engine engine E.

The intake passage 3, which is formed by an intake manifold fixed to the engine E, an intake pipe, etc., includes, in order from the upstream side (atmospheric side), an air cleaner, a compressor for the turbocharger 7, and an intake negative pressure changing means. An intake throttle valve 21 is provided.

The intake throttle valve 21 is driven to open by a diaphragm pressure response device 22. Pressure response device 2
2 is in a pressure chamber 22c partitioned by a Guia 7 ram 22b connected to a rod 22a that drives the intake throttle valve 21,
Atmospheric passage 24 that introduces atmospheric pressure Vat through air filter 23 and vacuum pressure V from vacuum pump 25
A vacuum passage 26 that guides vac is connected to the passage 24, and an electromagnetic switching valve 27 and an electromagnetic opening/closing valve 28 are interposed in these passages 24 and 26, respectively.

And the solenoids 27a, 28 of each electromagnetic valve 27, 28
When a control signal based on duty control is supplied from the ECtJ9 to a, each valve body 27b, 28b is suction-controlled, thereby reducing the negative pressure supplied to the pressure chamber 22c of the pressure response device 22. is adjusted, and the rod 22a
is drawn in as appropriate, and the amount of throttle of the intake throttle valve 21 is controlled.

Further, the intake passage 3 on the downstream side of the intake throttle valve 21 is provided with an E(:R passage 2[J
One end is open. Further, the end of the EGR passage 29 opens to the downstream side of the exhaust manifold of the exhaust passage 4.

An EGR valve 30 constituting an exhaust gas recirculation amount changing means is provided at the opening of the EGR passage 29 on the intake passage side. ing. Pressure response device 3
1 is a pressure chamber 31 partitioned off by a Guia 7 ram 311 connected to a rod 31a that drives the EGR valve 3 ().
c, an atmospheric passage 33 that introduces atmospheric pressure Vat through the air filter 32, and a vacuum passage 34 that introduces the vacuum pressure V vac from the vacuum pump 25 are connected to each other. An electromagnetic switching valve 35 and an electromagnetic on-off valve 36 are respectively provided.

And the solenoids 35a, 36 of each electromagnetic valve 35, 36
When a control signal by duty control is supplied from the ECU 9 to g, each valve body 35b, 36b is controlled to suck, thereby reducing the negative pressure supplied to the pressure chamber 31c of the pressure responsive device 31. is adjusted, the rod 31a is appropriately retracted, and the opening degree of the EGR valve 30 is controlled.

Note that the opening degree of the intake throttle valve 21 is detected by a feedback signal to the ECU 9 from the intake throttle valve opening degree sensor 45 attached to the rod 22a, and the opening degree of the EGR valve 30 is detected by the rod 31a of the pressure response device 31. This is detected by a feedback signal sent to the ECU 9 from the position sensor 39 that detects the movement of the .

When a control signal is supplied from the ECt 19 to the solenoid 37a of the solenoid valve 37, the valve body 37b is suction-controlled, and from this 1, the valve element 37b is passed through a passage 40 in which an autotrap 49' is interposed. Intake throttle valve 21
The downstream intake pressure is supplied to the pressure sensor 38 and the solenoid valve 37
When the valve body 37b protrudes, atmospheric pressure from the air filter 41 is supplied to the pressure sensor 38.

Furthermore, the injection pump 17 is provided with a diaphragm pressure response device 46 as an idle-up actuator that constitutes an idle-up mechanism.

This pressure-responsive device 46 includes a diaphragm 46b connected to a rod 46a that drives an idle-up control section in the injection pump 17.
An electromagnetic on-off valve (hereinafter referred to as "electromagnetic valve" as necessary) 47 is connected to the pressure chamber 46c partitioned by the pressure chamber 6b. 48, and the air filter 48 and pressure chamber 46c are normally in communication.

When a control signal based on duty control is supplied from the ECtJ9 to the idle-up actuator control solenoid 47a of the solenoid valve 47, the valve body 47b is suction-controlled. The pressure (negative pressure) supplied to the pressure chamber 46c! 14
1! i, the rod 46a is retracted as appropriate, and the idle up state (high speed idle state) is controlled.

Further, fuel injection timing control means 18 is capable of regenerating the DPO 5 by supplying high temperature gas for particulate combustion containing oxygen gas from the diesel engine E to the DPO 5 to combust the particulates collected by the DPOG.
retards the fuel injection timing of the injection pump 17
It is composed of a retardation device that adjusts the angle.

Here, since the injection pump 17 is configured as a distribution type injection pump, the fuel injection timing control means 18 drives the timer piston with the oil pressure (fuel pressure) from the hydraulic pump to connect the cam plate and the roller. Hydraulic automatic timer (internal timer) to move relative position
is used.

Note that the driver operates the accelerator pedal to increase the fuel injection amount to correct the decrease in output due to the delay in injection timing.

This hydraulic automatic timer is configured as a VE type timer, and is operated by the fuel pressure in the pump chamber 51 controlled by the regulating valve 50 as shown in Fig. 4.5. 52 is installed in the pump housing 53 so as to be perpendicular to the pump drive shaft 54, and slides within the timer housing song 53 due to the balance between changes in the oil pressure and the spring force of the timer springs 55a and S5b.
The movement of this timer screw 52 can be converted into a movement that rotates a cylindrical roller ring 57 via a slide pin 56.

Then, the position of the roller 57a attached to the a-lar ring 57 changes, and the timing at which the plunger 63 is actuated by the cam plate changes.

The timer springs 55a and S5b are the timer pistons 52
When the engine speed increases, the fuel pressure in the pump chamber 51 increases and the timer piston 5
2 is pushed overpowering the timer spring force, and the movement of the timer piston 52 causes the roller ring 57 to rotate in a direction opposite to the direction of rotation of the drive shaft, thereby advancing the injection timing.

Then, the oil supplied from the chamber 51 becomes high pressure in the plunger 63 and is supplied to the fuel injection/throttle 65 via the delivery valve 64.

Further, hydraulic passages 67a and 67b are provided which can communicate the high pressure chamber 73 and the low pressure chamber 74 of the timer piston 52.
A solenoid timer (opening/closing valve) ST equipped with an advanced characteristic switching boat (opening/closing part) 59 and a check valve 60 that improves the increase in oil pressure at engine startup are installed. A hydraulic passage 67a between them communicates with the oil tank 62 via an over 70-orifice 61.

Further, oil is supplied from the oil tank 62 to the pump chamber 51 by a feed pump 58.

The main body of the solenoid timer ST has a check valve 60.
An overflow orifice 61 is incorporated, and the pressure oil supplied from the pump chamber 51 is supplied to the switching port 59 by opening the check valve 60.

When the control signal is not supplied to the solenoid of the solenoid timer ST (when off), the switching boat 59
is open, middle advance at partial time (M)
When the control signal is supplied to the solenoid (
When the switch is on), the switching port 59 is closed, resulting in high advance (H) characteristics.

The hydraulic passage 67b is provided with an orifice 66 and a retard valve RV as an on-off valve, and the retard valve RV receives a control signal from the ECU 9 and, as shown in FIG. It is possible to switch between the characteristic and the low pan-kyu (L) characteristic.

As shown in FIGS. 4 and 5, the timer piston 52 receives pressure oil from the pump chamber 51 through an oil passage 52a to a high pressure chamber 73, and combines this oil pressure with two springs 5 on the low pressure chamber 74 side.
Due to the spring force from 5a and 55b, the timer piston 5
2 is adjusted, thereby rotating the roller ring 57 and adjusting the fuel injection timing.

That is, the stopper 7 fixed to the timer piston 52
A soft second timer spring 55b is interposed between the stone puff 1 and the retainer 68, and when the oil pressure increased by starting the engine E is supplied to the high pressure chamber 73, the stone puff 1 and the retainer 68 come into contact with each other. , the timer piston 52 moves so that the fuel injection timing reaches 5°A as shown in FIG.
TDC (After TOI) Death Cent
er).

Then, as the oil pressure increases appropriately by the load sensing timer mechanism according to the rotational speed of Ennon E, the first timer spring 55a is compressed and the timer piston 52 moves to the left in FIG. do.

That is, the retainer 68 is slidably inserted into the rod 69, and the first timer spring 55a is in a compressed state and held between the retainer 68 and the shim 70, which are locked by the snap ring 69a. As shown by the symbol Ct in Fig. 8, the engine speed changes from N1 to N2 (
>Nl), it is possible to obtain the characteristic of constant injection timing.

Note that the reference numeral 72 in FIG. 4 indicates an 0 ring.

In this way, when the reed valve RV is turned off (open), the fuel pressure becomes low through the passage 67b, so the pressure inside the high pressure chamber 73 becomes low regardless of the engine speed. , the timer piston 52 is pushed to the right in FIG. 4 by the first timer spring 55a and the second timer spring 551), and this causes
full retard) position.

By the way, the increase ΔQ in the fuel injection amount per stroke of the fuel injection pump 17 to obtain the output when the fuel injection timing is retarded greatly increases the thermal efficiency of the engine E by setting the retardation amount a. By lowering it, the effective work of Ennon E does not appear as an increase in the average effective pressure,
released as heat loss.

In other words, the amount of heat equivalent to the total fuel 1 per stroke is the sum of the amount of work and heat loss, but here, by setting the retard amount α, the amount of fuel equivalent to the fuel increase amount ΔQ is all converted to heat loss. However, the increase in exhaust gas temperature due to such heat loss and the combustion heat generated when incomplete combustion products are oxidized by the catalyst of D P O5J= cause the exhaust gas temperature to rise. .

Therefore, by delaying (retarding) the injection timing and simultaneously increasing the fuel injection amount as described above, the exhaust gas temperature at the same output operating point becomes higher and the DPO
Can burn particulates above 5, DP
O5 can be regenerated.

When the regeneration of the DPO 5 is completed, the ECU 9 outputs a signal to close the retard valve RV. At this time E
The CU 9 also outputs a signal for setting the intake throttle valve 21 to a predetermined opening degree.

When the retard valve RV closes, fuel pressure corresponding to the engine rotational speed comes to act on the high pressure chamber 73.

Note that the reference numeral 42 in FIG. 3 indicates a vehicle speed sensor.
Reference numerals 43 and 44 indicate temperature sensors for detecting engine temperature (coolant temperature in this case) as engine condition sensors, and reference numeral 75 indicates an awning lamp serving as a warning light.

The filter device for an exhaust pressure detection sensor of a diesel engine according to the present invention is constructed as described above, and the general flow of control of the entire system is first started by turning on the key switch (for example, in the accessory position).

First, the reproduction flag and the like are read, and the conditions under which the key was turned off in the previous operating state are read out from the memory.

As a result, if the regeneration flag is on, regeneration control is performed by controlling the injection timing and intake throttle amount, and whether or not regeneration has ended is determined based on the pressure drop of the DPO 5.

Further, if the regeneration flag is off, normal injection timing control and EGR control are performed. Then, based on the integrated value of diesel particulates, the pressure drop of DPO, etc., it is detected whether it is time for regeneration.

Next, when the end of playback control is detected and after determining the playback time, it is determined whether the key is off, and if the key is on, playback starts again.
Processing starts from the lagon.

That is, during non-reproduction, each of the above-mentioned processing flows is executed, and a state of waiting for the reproduction flag to be turned on continues.

The reproduction start determination processing flow is a processing flow for determining the reproduction start time and turning on the reproduction flag.

First, by sending a control signal to Tsuremaid 79a,
With the valve body 79b open and the valve body 78b closed, the pressure P2 on the downstream side of the DPO 5 is detected by the pressure sensor 10. Furthermore, with the valve body 78a open and the valve body 79b closed, the pressure sensor 10 detects the pressure P2 on the downstream side of the DPO5. 10 detects the pressure P1 on the upstream side of the DPO 5, the valve body 77b is opened, and the pressure sensor 10 detects the atmospheric pressure (approximately equal to the pressure on the downstream side of the muffler 6) Po.

At this time, since the filter devices 49a and 49b 1) appropriately reduce the pulsation of the exhaust pressure, variations in the measured values are reduced and accurate exhaust pressure can be detected.

The filter devices 49a and 49b prevent water, soot, etc. from entering the sensor diaphragm section of the pressure sensor 10, so that water may accumulate in the sensor diaphragm section and freeze in cold weather. The problem of the diaphragm being destroyed can also be solved.

In addition, since moisture can be purged into the exhaust passage 4 by the parts mechanism PM, there are no problems such as moisture accumulating in the slack part of the detection line and freezing, preventing exhaust pressure from being detected, or problems such as delays in exhaust pressure transmission due to soot. It can be resolved.

In addition, the parts mechanism PM includes a compressed air supply means (a compressor of the turbocharger 7), as shown in FIG.
When the supercharging pressure from 82 is 1 higher than the DPO upstream pressure, the ECU 9 determines that it is a purgeable region and controls the opening and closing of the solenoids 76at, 78a+, and 79a as appropriate.

And the above-mentioned pressure P. , p, , p2, the main muff pressure drop (p2-p,) and the DPO pressure drop (P, -P,) are calculated, and as shown in Fig. 9, the main muff pressure drop and I) F'
O pressure drop, for example, particulate) (Pet)
When the boundary line corresponding to the loading amount of 70 g moves from area C2 to area C3, the playback flag is turned on.

Then, when it is 708 or less, the regeneration flag is turned on when the integrated value of the pond is larger than the set value, and in other cases, the regeneration flag is maintained as it is.

Note that, instead of determining the amount of a-ding of Pet using the map described above, it may be determined whether the DPO pressure loss P is equal to or higher than the regeneration start setting pressure, and in this case,
As the DPO pressure drop P, a value measured once is used, or in order to eliminate variations in the measured values, a value obtained by taking the average value of a large number of measured values or a value subjected to other statistical processing is used.

The regeneration end determination process flow is a process flow that determines the regeneration end time and turns off the regeneration flag, and is performed almost similarly to the regeneration start determination process 70- to determine the main muff pressure loss (P2
-P, ) and the DPO pressure drop (P, -P2), as shown in FIG. The reproduction flag is turned off when the boundary line corresponding to the area C2 is moved from the area C2 to the area C1, and in other cases, the reproduction flag is maintained as it is.

The injection timing control processing flow is as shown in FIG.
The temperature T of O5, ie the DPO inlet temperature T in.

DPO internal temperature Tf or DPO outlet temperature T0 is detected, and if this temperature T is 650°C or higher, it is determined that the temperature is abnormally high, and based on the map (Ne, θ) at abnormally high temperature,
The injection timing is set to be determined by the engine rotation speed Ne and the pump lever opening degree θ.

That is, this map for abnormally high temperatures is internally set with a fuel injection timing that is advanced compared to the map for normal driving.

If the temperature T is 650 degrees Celsius or lower, and the regeneration flag is off, the injection timing is set to be determined by the engine speed Ne and the pump lever opening degree θ according to the map (Ne, θ) during normal driving. .

If the playback flag is on, the playback map (Ne.

θ), engine speed Ne and pump lever opening θ
The injection timing is determined by

By switching the solenoid timer ST on and off to achieve these set fuel injection timings to obtain high advanced characteristics or middle 7-speed characteristics, and by slowly switching the retard valve RV by duty control, To obtain high advanced characteristics or full retard characteristics.

At the time of this switching, the valve control of the full retard solenoid timer ST has a variation range of 11 to 28 degrees, so
Sudden switching causes acceleration/deceleration shocks. In order to reduce the shock during this switching, solenoid timer S
It takes a sufficiently long time by controlling the duty of T.

The switching takes place over a period of seconds (for example, 2-3 seconds).

The switching of the solenoid timer ST by this duty control is controlled according to a region (zone) divided by the engine rotation speed and the lever opening degree, for example, when transitioning from near the maximum output characteristic to a low engine rotation speed region. In order to stabilize the idle, switching is performed quickly by on/off switching, and when transitioning from a retarded state to maximum output near the maximum output characteristic,
In order to reduce the shock, switching is performed slowly using duty control.

Note that the switching time E is due to duty control. may be made a function of the Ennon rotation speed, or may be provided with time hysteresis. Moreover, each of the above-mentioned numerical values is an illustration.

According to the filter device for an exhaust pressure detection sensor of a diesel engine as an embodiment of the present invention, the following effects and advantages can be obtained.

(1) Taking into consideration that the combustion speed increases as the exhaust temperature rises, the timing of the end of DPO combustion or the timing of the state in which combustion continues even if the operation of the regeneration assist mechanism is stopped is set earlier. Moreover, it can be detected accurately.

(2) It is possible to appropriately control the stoppage of the operation of the regeneration assisting mechanism based on the regeneration assisting mechanism stop timing detected in accordance with item 1 above.

〔Effect of the invention〕

As described in detail above, according to the filter device for an exhaust pressure detection sensor of a diesel engine according to the present invention, the filter device installed in the pipe connecting the exhaust passage of an easel engine and the exhaust pressure detection sensor can be used. It has a simple structure consisting of a filter that collects soot in the exhaust, a wire mesh for a water trap and a volume for reducing exhaust pulsation, which are provided on the exhaust passage side of the filter in the casing. The following effects or advantages can be obtained.

(1) The wire mesh for the water trap can reliably trap moisture, thereby allowing exhaust gas from which moisture has been removed to be supplied to the pressure sensor.

(2) The exhaust pulsation reduction volume reduces exhaust pulsation, improves the detection accuracy of the pressure sensor, and further improves the durability of the filter and pressure sensor.

(3) The filter removes soot in the exhaust gas and moisture that could not be removed by the wire mesh.

[Brief explanation of the drawing]

The figure shows a regeneration device for a diesel particulate oxide oxidizer equipped with a filter device for an exhaust pressure detection sensor of diesel ennon as an embodiment of the present invention. A sectional view and a schematic diagram showing the main body of the filter device, Figure #2 is its overall configuration diagram,
3 is a block diagram thereof, FIG. 4 is a schematic configuration diagram showing the automatic timer of the VE type timer, FIG. 5 is a hydraulic system diagram thereof, and FIG. 6 is a configuration diagram showing the purge mechanism of the collected material, Figure 7 is a graph showing its effect, Figure 8 is a graph explaining its required advance angle characteristics (required fuel injection timing characteristics), and Figure 1I49 is a graph showing the amount of particulates accumulated in the DPO, main muff pressure drop, and DPO. A graph showing the relationship between pressure drop and FIG. 10 is a graph showing the action of the purge mechanism. 1. Cylinder block, 2. Cylinder head, 3.
・Intake passage, 4. Exhaust passage, 5. Deep collection type diesel particulate Y oxidizer <DPO), 6.
Muffler, 7...Turbo charge +, 8...Heating tube, 9
...Regeneration auxiliary mechanism control means, opening/closing valve control means. Arithmetic unit 1 Electronic control unit (ECU) that also serves as an operation end detection unit and a purge mechanism control unit, 10... Pressure sensor as an exhaust pressure detection sensor, 13... Air filter, 14 to 16
...Temperature sensor, 17.. Distribution type fuel injection pump as fuel injection timing adjustment means, 18.. Fuel injection timing control means constituting the regeneration auxiliary mechanism control means, 19.. Injection pump lever opening as an engine state sensor. degree sensor (load sensor), 20... Engine speed sensor as an engine condition sensor, 21... Intake throttle valve as intake negative pressure changing means, 22... Pressure response device, 22a... Rod,
22b...diaphragm, 22c...pressure chamber, 23...
F filter, 24... Atmospheric passage, 25... Vacuum pump, 26... Vacuum passage, 27° 28... Solenoid valve, 27a128a... Thread/id, 27b. 28b... Valve body, 29... EGR passage, 30... EGR valve constituting the exhaust gas recirculation amount changing means, 31... Pressure response device, 31a... Rod, 31b... Diaphragm, 3
1c...Pressure chamber, 32...Air filter, 33...Atmospheric passage, 34...Vacuum passage, 35-37...Solenoid valve, 35a, 36a, 37a...-Solenoid, 35b, 3
(31+. 37b...Valve body, 38...Pressure sensor, 39...Body sensor, 40...Passage, 41...Air filter, 4
2... Vehicle speed sensor, 43... Clock, 44... Water temperature sensor as an engine condition sensor, 45... Intake throttle valve opening sensor, 46... Idle up actuator configuring the idle up mechanism. 4
6b...Diaphragm, 46c...Pressure chamber, 47...Solenoid valve, 47a...Solenoid, 47b...Valve body, 48...
・Air filter, 49・・Casing, 49″・・Water Y wrap, 49a, 49b・・Filter device for exhaust pressure detection sensor, 49c・・Exhaust passage individual [], 49d
...Pressure sensor side outlet, 50...Regulating valve, 5]...Pump chamber, 52...Timer piston, 5
2a... Oil passage, 53... Bomb housing, 54... Pump drive shaft, 55g... 1st timer spring, 551)... 2nd timer spring, 56... Slide bin, 57... Roller ring, 578... ·roller,
58... Feed pump, 59... High advanced characteristic/middle advanced characteristic switching boat (opening/closing part), 60
・・Check valve, 61・・Over 70-orifice, 62・・Oil tank, 63・・Plunger, 64
・・Delivery valve, 65・・Fuel injection nozzle, 66・
・Orifice, 67a+G7b...Hydraulic passage, 68...
Retainer, 69... Rod, 69a... Snap ring, 70... Shim, 71... Stopper, 72... O'Jing, 73... High pressure chamber, 74... Low pressure chamber, 75... Awning lamp, 76~79...Solenoid switching valve, 76a~
79a...Solenoid, 76b-79b...Valve body, 80
...Air filter, 82...Compressed air supply means, 83.
・Gunbing volume for reducing exhaust pulsation, 84...Wire mesh, 85...1st stage filter, 85a...P
VF filter part, 8Sb-AC-26 filter part,
86... Second stage filter, 86a... PVF filter part, 86b... AC-26 filter part, 87... Spacer, 87a... Hole, 88. i'...FRMMO ring, 89...SUS plate, 90.91...Pressure sensor side volume, 92.93...Housing, 94
...Piping, E...Diesel engine, PM...Parts mechanism, RV...Retard valve as an on-off valve, ST...
・Solenoid timer as an on-off valve. Agent Patent Attorney Yoshihiko Iinuma Figure 1 (a) (b) Figure 4 Figure 5 Figure 8 Figure 9 Main muffler displacement (mmHg) -

Claims (1)

[Claims] In a filter device that is installed in a pipe that connects the exhaust passage of a diesel engine and an exhaust pressure detection sensor, there is a filter inside the casing that collects soot in the exhaust, and a filter that is located closer to the exhaust passage than the filter. A filter device for an exhaust pressure detection sensor of a diesel engine, comprising a wire mesh for a water trap and a volume for reducing exhaust pulsation.