JPH01257711A - Purger for particulate trap - Google Patents

Abstract

PURPOSE:To surely purge a deposit in a pressure pipe by providing an electromagnet valve in a bypass pipe which connects the inlet side pipe of a pressure sensor for a particulate trap to an outlet side pipe. CONSTITUTION:An electromagnet valve 2 is provided in a bypass pipe 5 which connects the inlet side pipe 4a of a pressure sensor 1 for a particulate trap to an outlet side pipe. The electromagnet valve 2 is opened when reaching to a predetermined condition required for purging to flow exhaust gas in the pipes 4a, 4b, 5 for purging a deposit. Accordingly, the deposit in the pressure pipes can be purely purged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a particulate trap, and particularly to a purge device for purging (scavenging) deposits accumulated in a pressure detection pipe of the trap.

[Conventional technology]

In conventional particulate traps (hereinafter simply referred to as traps), the amount of gas introduced into the trap for determining the reburning timing and continuing reburning is determined using the trap and a fixed orifice (located on the downstream side of the trap). This is generally done based on the output value of a pressure sensor attached to a silencer.

However, when the carbon particles and water vapor contained in the exhaust gas flowing into the trap are cooled by the outside air, they stick to the trap's pressure sensor and the piping that connects the sensor to the trap, and as the amount of carbon particles and water vapor accumulated increases, eventually This sometimes clogged the piping and made pressure detection impossible.

Therefore, in order to remove deposits such as carbon particles and scavenge the piping, it has been necessary to purge the piping by flowing pressurized gas at regular intervals or travel distances.

A conventional device for purging deposits in a pipe leading to a pressure detection portion of a trap using pressurized gas is disclosed in, for example, Japanese Patent Laid-Open No. 61-93222. To briefly explain this based on FIG. 3, in FIG.
It communicates with the inlet side and the outlet side of the trap 6 by a pipe 4b on the outlet side and a pipe 4c commonly connected to the pipes 4a and 4b. Of these, pipes 4a and 4b
filters 25a, 25b and solenoid valve 3a, respectively.
, a solenoid valve 3b is provided. Further, the downstream side of the compressor of the turbocharger 21 as a supply source of purge pressure gas and the pipe 4C are in communication via the check valve 22 and the solenoid valve 2. Note that 23 is an atmospheric pressure valve that is operated when measuring atmospheric pressure.

In operation, a controller (not shown) keeps all solenoid valves closed during normal playing card operation. When purging is performed, the compressed air from the turbocharger 21 is opened to flow through the filter 25a and its piping 4a by opening the solenoid valves 2 and 3a, and the filter 25b and the piping 4a are flowed by opening the solenoid valves 2 and 3b. It flows into the pipe 4b.

As a result, the filters 25a, 25b and the pipes 4a, 4
b, The deposits accumulated in 4C are purged to the exhaust pipe.

[Problems to be Solved by the Invention] In the conventional purge device as described above, the supercharging pressure generated downstream of the compressor of the turbocharger, which is provided outside the 1-lap as a pressure gas supply source for purging, is When the engine is under low load or at low speed, the boost pressure becomes lower than the exhaust pressure at the inlet and outlet sides of the trap, making it impossible to flow the boost pressure into the piping, making it difficult to purge deposits. can't do it. Also,
The problem was that it could not be used to trap engines without a turbocharger.

Therefore, an object of the present invention is to provide a particulate playing card purging device that can reliably purge deposits in the pressure piping of a trap without using pressure gas from a pressure gas supply source provided outside the playing card. It is in.

[Means for Solving the Problems] As a means for achieving the above object, a particulate 1-lap purging device according to the present invention includes a pressure sensor for a particulate tramp and an inlet from the trap to the sensor. It is equipped with a solenoid valve provided in a bypass pipe connecting the side pipe and the outlet side pipe, and a control means for controlling the solenoid valve to open when a predetermined condition necessary for purging is reached.

[For production]

In the present invention, when purging deposits in the inlet and outlet piping of the lamp communicating from the trap to the pressure sensor, the control means controls the electromagnetic The valves are controlled to open, and exhaust gas is allowed to flow through the inlet side piping, bypass piping, and outlet side piping to purge deposits in these pipings.

〔Example〕

Embodiments of the particulate trap purging device according to the present invention will be described below.

FIG. 1 shows the configuration of an embodiment of a particulate lamp purge device according to the present invention, in which 1 is a pressure sensor, 2 is a solenoid valve, 3a is a solenoid valve on the inlet side of a trap 6, and 3
b is a solenoid valve on the output 1'' side of the trap 6; 4a and 4b are inlet-side piping and outlet-side piping that communicate the pressure sensor 1 and the inlet and outlet sides of the 1-wrap 6, respectively; 5 is the piping 4a
, bypass piping connecting 4b, 7 is an engine (not shown)
Exhaust pipe, 8 is Trump's Roharb, 9 is a bypass valve, 10 is an electric heater installed at the inlet of L-lap 6, 1
1 is the inlet temperature sensor of the trap 6, 12 is the electric heater 1
0 is an on/off relay, 13 is a bypass pipe through which most of the exhaust gas flows when the trap 6 reburns, 14 is a controller as a control means, and 15 is a fixed throttle provided on the downstream side of the trap 6 ( silencer).

FIG. 2 is a flowchart of a deposit purge program stored and executed by the controller 14 shown in FIG. 1, and the operation of the configuration shown in FIG. 1 will be explained based on this flowchart.

First, during normal collection of playing cards 6, the solenoid valve 2 is closed, the solenoid valves 3a and 3b are opened, the trapper Roharb 8 is opened to a predetermined opening degree, and the bypass valve 9 is closed. Therefore, the pressure sensor 1 works as a differential pressure sensor.

In this state, the controller 14 operates the pipes 4a, 4b and 5.
In order to determine whether predetermined conditions necessary for purging the deposits have been reached, the elapsed time (or distance traveled when using a distance sensor (not shown)) since the previous purge is set in advance. Check whether the set value has been reached (step S1 in FIG. 2), and if the set value has not been reached, then the differential pressure across the trap 6 by the pressure sensor 1 performs effective purging. As a predetermined condition for this, it is checked whether a value determined and set in advance through experiments or the like has been reached (step S2). This step S2 is performed because the process of purging the deposits is carried out more effectively as the flow rate of the fluid flowing inside the pipe (which is proportional to the pressure difference across the pipe) is larger. If the pressure difference between the front and rear reaches the value determined and set in advance through experiments etc. for purging, it is considered that not only the trap 6 but also the deposits in the pipes 4a and 4b have reached a certain amount, so step S1
Even if it is determined that the purge time has not yet been reached,
This is because it is better to purge.

If neither of the checks in steps S1 and S2 reaches the set value, these steps are repeated; however, if it is determined in step S1 or S2 that the set value has been reached,
The controller 14 opens the solenoid valve 2 and closes the solenoid valves 3a and 3.
b is closed to perform purging (step S3). That is, by this control, a part of the exhaust gas flowing through the exhaust pipe 7 is caused to flow into the artificial side pipe 4a, the bypass pipe 5, and the outlet side pipe 4b as shown by arrow B in FIG. 1, bypassing the trap 6. Pipes 4a, 5, and 4 due to the flow of exhaust gas
The deposits accumulated in the trap 6 are discharged to the exit side of the trap 6. - Next, the controller 14 controls this state to be maintained for a set time t1, and when it determines that the set time t1 has elapsed (step S4), it closes the solenoid valve 2 and closes the solenoid valves 3a and 3b. It is opened to return to the normal pressure detection state (step S5).

Then, in order to enhance the purging effect of the deposits in the pipes 4a and 5.4b, this purge operation is repeated n times (steps 53 to S6), and when it is determined that the number of times has reached n, Reset the elapsed time (or mileage) until the purge to zero (Seven S7)
, exit this program.

In the embodiment of the present invention shown in FIG. 1, a total of three solenoid valves are provided, one each on the bypass piping 5, the inlet side of the trap 6, and the outlet side piping 4a, 4b. When the solenoid valve 2 is opened, the exhaust gas flows as shown by arrow B in FIG. This flow creates a negative pressure in the piping portion of the piping 4a, 4b closer to the sensor 1 than the solenoid valves 3a, 3b, and the exhaust gas staying in this portion is sucked out to the outlet piping 4b side of the trap 6. Because of this tendency, the sediment will be sucked out along with it.

Therefore, either one of the inlet-side solenoid valve 3a and the outlet-side solenoid valve 3b may be used, or both may not be conjugated (since both sides of the differential pressure sensor 1 are not in communication).

Further, although the pressure sensor 1 is used as a differential pressure sensor, it may be used to detect the pressure only in the inlet side piping 4a or the outlet side piping 4b of the trap 6. In this case,
It simply works as a pressure (inlet pressure, outlet pressure) sensor.

Furthermore, in the conventional particulate trap reburning device, which determines the reburning timing based on the differential pressure across the trap 6, a fixed throttle 15 is installed on the downstream side of the trap in order to accurately calculate the differential pressure across the trap. In some cases, a silencer is provided, and a pressure sensor 1 for detecting the differential pressure between the front and rear is provided.
The fixed aperture 15 may be provided with the same configuration as the one enclosed in .

Furthermore, the program shown in the flowchart shown in FIG. 2 performed in the particulate trap purge device according to the present invention can be replaced with the reburning program performed in the conventional particulate trap reburning device (the electric heater and its electric heater shown in FIG. 1). This purge program is preferably carried out before the reburn program when carried out in combination with a program executed by the on/off relay 12 as well as the inlet temperature sensor 11, etc. For this purpose, it is necessary to set the set values in steps S1 and S2 lower than the time (or distance) and differential pressure set values used for determining the reburning timing.

〔Effect of the invention〕

As described above, the particulate trap purging device of the present invention is configured to purge the deposits in the piping to the pressure sensor using the exhaust gas flowing into the trap. It is not necessary and is not dependent on the state, and has the effect of purging tramp deposits even in an engine without a turbocharger.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a particulate-1-1 to lap purge device according to the present invention, and FIG. 2 is a flowchart of a program stored and executed in a controller used in the present invention. FIG. 3 is a block diagram of a conventional purge device disclosed in Japanese Unexamined Patent Publication No. 61-93222. In FIG. 1, 1 is a pressure sensor, 2 is a solenoid valve, 4a,
4b are the inlet and outlet pipes of the trap 6, respectively;
does not show a bypass pipe that bypasses the pipes 4a and 4b, 6 a trap, and 14 a controller as a control means. In the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] A solenoid valve is installed in the pressure sensor of the particulate trap and the bypass piping connecting the inlet and outlet piping from the trap to the sensor, and the solenoid valve is opened when a predetermined condition necessary for purging is reached. a control means for controlling the
A particulate trap purge device comprising: