JPS59194021A - Restoring equipment for diesel particulate trap - Google Patents

Abstract

PURPOSE:To burn up particulates in a short duration when a trap is restored by controlling the quantity of supplied oxygen gas which is involved in particulate burning hot gas fed to said trap. CONSTITUTION:For restorating a trap since a filter 4 which collects particulates within exhaust gas is clogged, fuel which is boosted in pressure by an injection pump 1 is fed to a fuel injection nozzle 35 of a burner 34 in a high temperature gas supply mechanism C. After air is sent from the primary and secondary air pumps 41 and 42 to a burner 34, it burns the air to produce high temperature gas, which is fed into a particulate device 24 to reclear the filter 4. If the temperature of the filter at the lower site thereof detected by a temperature sensor 46 is increased over a specified valve at the rate over a spcified value, a fuel flow control valve 3 is controlled to increase the flow rate of fuel fed to the burner 34 and to reduce the supply rate of oxygen gas involved in high temperature gas.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a particulate lamp regeneration device in an exhaust gas system of a diesel engine.

Conventionally [1], particulate traps (for example, diesel particulate traps) are installed in the exhaust system of diesel engines.
Various devices have been developed that are equipped with filters to prevent the generation of black smoke, etc., and these conventional particulate trap devices are equipped with a particulate trap regeneration device that burns the particulates. This particulate trap regeneration device is provided with a fuel pressure regulator and a fuel flow control valve for supplying fuel.

The fuel supplied from these conventional fuel pressure regulators and fuel flow control valves has its flow rate and pressure adjusted and is sent to the combustion type heater of the particulate tramp device τj.

The particulate trap device is regenerated by activating this heater to burn particulates trapped in the trap device.

However, the conventional particulate lapping device has a problem in that the temperature of the diesel particulate filter becomes extremely high when the particulates are combusted. When the temperature of the filter exceeds 1000° C., there is a problem that a crank occurs. Furthermore, when the temperature of the filter exceeds 1200° C., there is a problem that the filter itself is melted and damaged.

The occurrence of cracks and melting damage are particularly significant in the downstream portion of the center of the filter where the temperature is particularly high.

The present invention aims to solve these problems.
When regenerating particulate matter playing cards, the temperature of the particulate matter lamp is prevented from exceeding a predetermined temperature by controlling the supply amount of oxygen gas contained in the high temperature gas for particulate combustion supplied to the particulate matter 1 trap. The purpose of the present invention is to provide a diesel particulate wrap regeneration device that is capable of regenerating diesel particulate matter.

Therefore, in order to regenerate the particulate trap in the exhaust gas system of a diesel engine, the diesel particulate trap regeneration device of the present invention has a high temperature that can supply high temperature gas for particulate combustion containing oxygen gas to the particulate lamp. It is equipped with a gas supply mechanism, a temperature sensor for detecting the temperature of the downstream part of the above-mentioned particulate lamp, a differentiator that takes the differential of the detected temperature from the temperature sensor with respect to time, and a temperature signal from the above-mentioned temperature sensor. Depending on the differential signal from the above differentiator,
The apparatus is characterized in that a high-temperature gas control means for controlling the amount of oxygen supplied by the high-temperature gas is provided.

Below, a diesel particulate wrap regeneration device as an embodiment of the present invention will be explained with reference to the drawings.
Figure 1 is its overall configuration diagram, Figure 2 is its bronch diagram, @
Figure 3 is a graph showing the effect.

As shown in FIGS. 1 and 2, engine E has its Schilling Pro/18. 1 shilling head and 20 pistons
It has a main chamber 21 formed by a shilling head, and a sub-chamber (not shown) formed in one shilling head and communicating with the main chamber 21.

Further, an intake passage 22 is connected to the main chamber 21 of the diesel engine E via an intake valve (not shown), and an exhaust passage 23 is connected to the main chamber 21 via an air bleed valve (not shown). is a diesel particulate truck that captures particulates in exhaust gas.
A diesel particulate filter (DPF) 4 constituting a filter device (DPF device) 24 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 temperatures below about 500°C (34°C in the presence of an oxidation catalyst). 'C or higher) will self-ignite.

Further, this DPF device 24 has a honeycomb-shaped filter 11 inside thereof, but instead of this honeycomb-shaped filter, it may be equipped with a mesh filter or a porous filter inside.

The DPF device 24 is in communication with the atmosphere via a 77 roller 25, and in the state shown in FIG.
is in the closed state shown by the solid line in FIG. 1, traps particulates supplied through the exhaust passage 23, and exhaust gas from which the particulates have been removed is discharged to the atmosphere.

Then, by a timer or the like (not shown), the passage switching valve 26 is switched to the state shown by the broken line in FIG. 1 by the switch valve 29, and the hot air supply control valve 27 is further switched to the state shown by the broken line in FIG. It becomes open.

Further, the exhaust passage 23 is communicated with the atmosphere via the bypass passage 32 and the pre-muffler 28 upper and 77 roller 31, and the exhaust side 24 of the DPF device 24 is connected to the atmosphere.
a is communicated to the atmosphere via 77r 25, and D
The intake side 24b of the PF device 24 is communicated with the burner 34.

This state is a regeneration state of the DPF device 24, and the DPF device 24 is regenerated by high-temperature gas supplied from the burner 34.
The particulates trapped in the fuel are burned.

The cono burner 34 is supplied with a L% charge of 7 fuel injections 35.

The fuel injection nozzle 35 is supplied with high temperature gas (
Injection pump constituting structure C1. Fuel regulated to a set pressure by the fuel pressure regulator 2 and fuel flow control valve 3 is supplied under duty control.

This duty control is performed by an electric control device (ECU device) 15 as a high-temperature gas control means, and this ECU device 15 receives an opening signal from an injection pump lever opening sensor 36 and an engine rotation speed. It receives a rotational speed signal from a sensor 37, a temperature signal from a cooling water temperature sensor 38, a temperature signal from a gas temperature sensor 39, and a pressure signal from a gas pressure sensor 40.

Further, a temperature signal from a DPF downstream temperature sensor 46 that detects the temperature of the downstream portion 4a of the DPF 4 is sent to the ECU device 15.
5, a differential signal obtained by time-differentiating the temperature signal or a domain separator 55
It is now being sent in bulk.

The EC1J device 15 receives these signals and outputs a pulse control signal that drives the slide/id of the fuel flow control valve 3.

This pulse control signal is a signal that controls the opening time of the control valve 3 depending on the number of pulses.

Note that this differentiator 55 may be omitted, in which case,
The ECU device 15 is configured to appropriately calculate the deviation of the temperature signal per unit time within the ECU device 15. That is, the ECU device 15 is configured to have both the function of a high temperature gas control means and the function of a differentiator.

The ECU device 15 controls the rotational states of the primary air pump 41 and the secondary air pump 42 in response to each of the above signals, and also controls the ignition timing of the spark plug 57 in the burner 34 via the ignition coil (1g coil) 43. In addition, the control solenoids of the switch valves 29, 30 and 44, 45 are controlled.

The ECU device 15 sends control signals to the switch valves 29 and 30 so as to interlock them, and also switches the switch valves 29 and 30.

A control signal is also sent to these valves 30 and 44 so as to interlock them.

In addition, numerals 47 to 49 in FIG. 1 all indicate air cleaners, 50 is an air flow control valve that controls the large flow blower from the secondary air pump 42, 51 is a protection valve for the fuel injection nozzle 35, and 52 54 indicates a passage, and 56 indicates an exhaust port.

Since the diesel particulate ()) lamp regeneration device of the present invention is configured as described above, when the gas from the diesel engine passes through the filter 4, the particulates in the trapped gas are collected and purified. The exhaust gas is released to the atmosphere through the exhaust port 56.

Then, in order to regenerate the diesel particulate filter 4, high temperature gas for particulate combustion is supplied from the heater 34 in the diesel particulate device 24.

At this time, the temperature of the high temperature gas is determined by the amount of combustion fuel supplied to the burner 34 from the fuel flow control valve 3, and the amount of oxygen gas supplied in the high temperature gas is determined by the amount of oxygen gas supplied to the burner 34 from each air pump 41, 4. It is determined by the amount of air supplied from 2 and the amount of combustion fuel supplied from fuel flow control valve 3.

In this way, the high temperature gas whose supply amount of oxygen gas is appropriately regulated is supplied to the DPF 4, and the particulates 1 are combusted.

Then, as shown in FIG. 3, the temperature on the downstream side of the DPF 4 gradually rises, and the DPF downstream temperature T measured by the DPF downstream temperature sensor 46 becomes equal to or higher than the predetermined temperature Ta, and the differentiator 55 When the differential signal from the burner 34 exceeds a predetermined value, a control signal is sent to the fuel flow control valve 3 to increase the fuel flow rate to the burner 34 in order to reduce the amount of oxygen gas supplied to the high temperature gas. control is performed.

That is, assuming that the entire fuel supply is combusted,
The remaining oxygen gas supply amount is controlled by the fuel supply amount to the burner 34.

Then, when both of the following equations are satisfied, the amount of oxygen gas supplied as the high temperature gas is controlled to decrease.

T≧Ta...(1)i
To To-1i/Δt≧D..., (2
)(Δ””1tn-1t,l) Here, the subscript! ] indicates discrete time, and ΔF is
It shows the unit time width between discrete times.

1) P F 4 continues to burn particulates 1 even though it receives high-temperature gas that is controlled to reduce the amount of oxygen gas supplied, and reaches the temperature shown by the symbol T max in FIG. 3. The temperature in the downstream section 4a of the DPF 4 rises by 2''.

At this time, the temperature Tl1laX is below the melting damage start temperature of the DPF 4.

That is, the temperature T of the DPF 4 is equal to or higher than the predetermined value Ta, and
When the differential value is above a predetermined value, the fuel flow rate to the burner 34 is increased in accordance with the control signal from the ECtJ device 15, and when the oxygen concentration is controlled to be O, the DPF
The value to which the maximum temperature T max of No. 4 rises can be determined in advance by Δ111.

Based on this prediction, each constant Ta, D is determined in advance.

In this way, the temperature of the DPF 4 can be raised to the predetermined temperature Tc in the shortest time without melting and damaging the DPF 4, and the combustion of particulates can be continued.

Initial combustion state up to this maximum temperature Tmax (time O~
t1) is indicated by the symbol A in FIG. 3, and the combustion state after the maximum temperature T max (time, ~) is indicated by the symbol B in FIG. 3.

Further, in the combustion state B, the state is as shown in the following equation, and the amount of fuel supplied from the fuel flow control valve 3- is constant.

(Tn T,, +)/Δt≦0 (3) Furthermore, a control signal is sent from the EC1J device 15 to each air pump 41.42 to control the air amount to be reduced, and the oxygen gas supplied to the DPF 4 is controlled. The amount may be decreased, and in this case as well, the amount of oxygen gas supplied in the high temperature gas can be appropriately controlled.

In addition, the temperature of the downstream part 4a of the DPF 4 is also affected by the amount of particulates, so when the detection signal from the gas pressure sensor detects a large pressure drop, that is, a large amount of particulates, the oxygen gas Control may be performed to reduce the supply amount.

As described in detail above, according to the diesel particulate trap regeneration device of the present invention, in order to regenerate the particulate lamp in the exhaust gas system of a diesel engine, the particulate trap containing oxygen gas is sent to the particulate trap at a high temperature for combustion. A temperature sensor for detecting the temperature of the downstream part of the particulate 1 card, which is equipped with a high-temperature gas supply mechanism for supplying gas, and a differentiator for differentiating the temperature detected by the same temperature sensor with respect to time;
The particulate trap has a simple structure in which a high-temperature gas control means is provided to control the amount of oxygen gas supplied by the high-temperature gas according to the temperature signal from the second temperature sensor and the differential signal from the differentiator. It has the advantage of being able to prevent the temperature of the particulate matter from rising above a predetermined temperature, thereby reliably preventing the occurrence of cracks in the particulate matter, and also eliminating the melting of the particulate matter lamp. However, the diesel particulate lamp regeneration device of the present invention has the advantage of being able to burn particulates in a short period of time, and the high temperature gas is regenerated according to the temperature signal from the temperature sensor and its differential value. Since the amount of oxygen gas supplied can be controlled by feedbank, appropriate control can be performed even if the components of the device deteriorate.

[Brief explanation of the drawing]

The figures show a diesel particulate regenerating device as an embodiment of the present invention. Fig. 1 is its overall configuration, Fig. 2 is its block diagram, and Fig. 1iS3 shows its operation. It is a graph. 1. Injection pump, 2. Fuel pressure regulator, 3. Fuel flow control valve, 4. Diesel particulate filter (DPF), 4a. Downstream section, 15. Electrical control device as high temperature gas control means ( ECU device), 18...
Cylinder block, 19... Cylinder head, 20...
Piston, 21... Main chamber, 22... Intake passage, 23...
Exhaust passage, 24...Diesel buttiki erate tramp device (DPF device), 24a...Exhaust side, 24b...
Intake side, 25...77 lar, 26...passage switching valve, 27
・Hot air supply control valve, 28 ・Premuffler, 2. 30...Switch valve, 31...77ler, 32...
Bypass passage, 34...Burner as a combustion type heater, 35...Fuel injection nozzle, 36...Injection pump lever opening sensor, 37...Ennon rotation speed sensor, 38...
Cooling water temperature sensor, 39... Gas temperature sensor, 40... Gas pressure sensor, 41... Primary air pump, 42... Secondary air pump, 43... Ignition fill (Ig coil), 44, 45... Switch valve, 46...DP
F downstream temperature sensor, 47-49... air cleaner, 5
0...Air flow control valve, 51...Nozzle protection valve, 52~
54... Passage, 55... Differentiator, 56... Exhaust port, 57
... Spark plug, C. High temperature gas supply mechanism, E. Engine. Sub-Agent Patent Attorney Yoshihiko Iinuma

Claims (1)

[Claims] In order to regenerate the particulate trap in the exhaust gas system of a diesel engine, a high-temperature gas supply island capable of supplying high-temperature gas for particulate combustion containing oxygen gas to the particulate trap is provided, and a A temperature sensor for detecting temperature, a differentiator that takes the differential of the detected temperature from the temperature sensor with respect to time, and a temperature signal from the temperature sensor and a differential signal from the differentiator. A diesel batticure) lap regeneration device characterized by being provided with high temperature gas control means for controlling the amount of oxygen gas supplied.