JPH07197805A - Device for removing minute particulate in exhaust gas - Google Patents

Abstract

PURPOSE:To suppress generation of cracks and fusion loss in re-generating a trap device by trapping particulates of constantly appropriate amount by a trap device to trap the particulates in the exhaust gas from the engine. CONSTITUTION:Trap devices 8, 9 are respectively arranged on exhaust pipes 4, 5 of an on-vehicle engine 1 to trap particulates by filters 15, 16 and to re-generate the filters 15, 16 alternately, and the time for trapping particulates to be set by a controller 26 is reduced the more when the temperature of the intake to be detected by a temperature sensor 27 is the higher, and is reduced more while an air-conditioner 24 is in operation than it is not in operation, and becomes constant during idling.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for trapping particulate matter, so-called particulate matter, contained in exhaust gas of an engine by a filter of a trap device to remove particulate matter from the exhaust gas. The present invention relates to a device that corrects a collection time according to a driving situation of a vehicle.

[0002]

2. Description of the Related Art In a conventional device for collecting particulates contained in the exhaust gas of a diesel engine by a filter of a trap device to remove the particulates from the exhaust gas, a filter is used every time the engine is operated for a certain period of time. The particulates trapped in are burned and the filter is regenerated. However, when the intake air temperature of the engine rises, the intake air density decreases and the intake oxygen amount into the engine decreases, so the amount of particulates in the exhaust tends to increase. When the air conditioner is operating,
The fuel consumption of the engine is larger than that when the air conditioner is not operating, and the amount of particulates in the exhaust gas is also increased.

Therefore, in the above trap device which regenerates the filter at every constant operating time, when the intake air temperature is relatively high and the air conditioner is continuously operating, the trapping is performed by the filter within the constant operating time of the engine. Since the amount of collected particulates becomes excessive, cracks and melting damage may occur in the filter due to overheating during filter regeneration, and the function of the trap device may be impaired. Detecting inactivity and changing the collection time of the filter,
Attempts have been made to control the amount of particulates collected by the filter. However, during idling operation after the vehicle has stopped, the radiant heat of the engine has a greater effect on the intake air temperature due to a decrease in the intake air amount. As a result of the collection time being set to be short, the filter is regenerated with a small amount of collected particulates, which may unnecessarily increase the number of regenerations.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a filter of a trap device for trapping particulates in engine exhaust is controlled appropriately for its trapping time.
It is intended to always collect an appropriate amount of particulates so that the trap device can be efficiently regenerated.

[0005]

Therefore, an exhaust particle removing device according to the present invention is a trap device for collecting particles in an engine exhaust, and the particles collected by the trap device are set every set collection time. Regenerating means for removing, temperature sensor for detecting intake air temperature of the engine, vehicle stop detecting means for detecting stop of a vehicle equipped with the engine, and the set collection time by output of the temperature sensor and vehicle stop detecting means. It has a correction means for correcting.

[0006]

That is, the time for trapping the particulates by the trap device is an appropriate length depending on the intake air temperature of the engine detected by the temperature sensor and the presence or absence of the vehicle stop detected by the vehicle stop detection means. Since it is set to, the amount of fine particles collected when removed by the regenerating means,
The amount can be adjusted to an appropriate amount at any time regardless of the operating condition of the vehicle, etc., and the fine particles collected by the trap device are removed from the trap device by the regenerating means every set collection time.

[0007]

Embodiments of the present invention shown in the drawings will be described below. In FIG. 1, a diesel engine 1 mounted on a vehicle is supplied with intake air from an air cleaner 2 through an intake pipe 3, and exhaust gas is exhausted from bifurcated exhaust pipes 4 and 5 to exhaust pipes 4 and 5. Are valves 6 and 7, respectively
And trap devices 8 and 9 are installed.

Further, the conduits 11 and 12 for supplying air from the air pump 10 are provided with the valves 6 of the exhaust pipes 4 and 5, respectively.
7 and the trap device 8 and 9 are connected to each other, and the conduit 1
Normally closed valves 13 and 14 are provided in the valves 1 and 12, respectively. The trap devices 8 and 9 respectively include filters 15 and 16 for collecting the particulates in the exhaust gas,
Electric heaters 17 and 18 and heat reflection plates 19 and 20 are provided, and the electric heaters 17 and 18 are provided with switches 21 and 18, respectively.
It is connected to the battery 23 via 22.

On the other hand, the air conditioner 24 is driven by the engine 1, the switch 25 for detecting the operation / non-operation of the air conditioner 24 sends the detection signal to the controller 26, and the temperature sensor 27 installed in the air cleaner 2 is also provided. Sends the intake air temperature signal in the air cleaner 2 to the controller 26. In addition to the above signals, the controller 26 informs the controller 26 of the rotation speed and load of the engine 1, the vehicle speed by a vehicle speed sensor (not shown), and the vehicle speed sensor. Various signals that indicate the condition of the vehicle or engine, such as a vehicle stop signal due to a vehicle stop signal, a shift lever parking position signal due to a shift lever position detection device of a transmission, a vehicle stop signal due to an output of a parking brake operation detection device, etc. Has been thrown in.

The engine 1 includes an air cleaner 2 to an intake pipe 3
The intake pipe supplied via the exhaust pipe 4 is operated by fuel supplied from a fuel injection pump (not shown).
The valves 6 and 7 arranged in the controller 5 are respectively the controller 2
6 are alternately opened and closed in reverse, and when valve 6 is open and valve 7 is closed, as shown in FIG.
Exhaust gas from the engine 1 flows into the exhaust pipe 4 and traps 8
And the particulates contained in the exhaust gas are collected by the filter 15 and the purified exhaust gas is released to the atmosphere.

During the set collection time described below, the filter 15
When the particulates are collected by the controller 26, the controller 6 closes the valve 6 and opens the valve 7, the exhaust gas of the engine 1 flows into the other exhaust pipe 5 and is guided to the trap device 9, and is included in the exhaust gas. The collected particulates are collected by the filter 16.

On the other hand, the controller 21 closes the switch 21 to energize the electric heater 17, and the heat generated in the electric heater 17 and reflected by the heat reflection plate 19 causes
The particulates collected in the filter 15 are sufficiently heated, the controller 26 drives the air pump 10 and opens the valve 13, and the air sent from the conduit 11 to the filter 15 causes the particulates in the filter 15 to be discharged. Are burned and the filter 15 is regenerated. When the filter 16 collects the particulates during the next set collection time, the same operation as above is performed to start collecting the particulates by the filter 15 and regenerate the filter 16. By repeating the above, the particulates in the exhaust are constantly removed.

When the filters 15 and 16 of the trap devices 8 and 9 are regenerated as described above, the temperatures of the filters 15 and 16 increase almost in proportion to the amount of the particulates trapped in them. In order to prevent the filters 15 and 16 from cracking and melting due to overheating during regeneration, it is necessary to adjust the amount of particulate collection by the filters 15 and 16 to an appropriate amount.

However, the amount of particulates trapped by the filters 15 and 16 fluctuates depending on the intake air temperature of the engine and whether or not the air conditioner operates, as described above, in addition to the simple trapping time. The particulate collection time H by the filters 15 and 16 is controlled by the controller 26 in response to these situations.
That is, an appropriate reference collection time Ho at the reference temperature T of the intake air is determined, and as shown in FIG.
Depending on the intake air temperature, the reduction rate of the reference collection time Ho is increased / decreased in a stepwise manner. When the air conditioner is not operating, the solid line is adjusted, and when the air conditioner is operating, the broken line As a result of the adjustment, the particulate collection time H by the filters 15 and 16 is shortened as the intake air temperature becomes higher than the reference temperature T by the correction by dividing the reference collection time Ho by the reduction rate. It is set so that the temperature is extended as the temperature is lower than the reference temperature T, and is shortened when the air conditioner is operating than when it is not operating.

Further, during idling operation immediately after the running vehicle stops, the intake air amount decreases, so that the intake air temperature detected by the temperature sensor 27 easily rises due to the influence of the radiant heat received from the engine, and therefore, With the above-described setting of the particulate collection time H, there is a tendency that the collection time becomes too short during the idling operation in which the particulate discharge amount is small.

Therefore, at the time of idling operation immediately after the vehicle stops, the increase / decrease correction of the reference collection time Ho according to the intake air temperature is stopped, and the controller 26 is stopped.
However, while the particulate collection time H by the filters 15 and 16 when the air conditioner is not operating is set to a constant collection time H1, the particulate collection time H is set to the above when the air conditioner is operating. The collection time H2 is set to be a predetermined time longer than the collection time H1.

Next, the procedure for setting the particulate collection time H by the controller 26 will be described with reference to FIG. For each of the trap devices 8 and 9, first, in step 30, it is checked whether the rotation speed N of the engine 1 is 0. If the engine 1 is stopped, the routine ends, but the engine 1 is operated. If so, go to step 31.

In step 31, it is checked whether or not the exhaust gas is guided to each of the trap devices 8 and 9 by opening and closing the valves 6 and 7 arranged in the exhaust pipes 4 and 5, and if the exhaust gas is guided. The routine ends, but if exhaust is not being guided, the routine proceeds to step 32.

In step 32, it is checked whether or not the vehicle speed V is 0, and if it is detected that the vehicle is running by the output of the vehicle speed sensor or the like, the next step 3
3, the intake air temperature is read by the signal from the temperature sensor 27 at step 33, and the routine proceeds to step 34.

In step 34, it is checked by the signal from the switch 25 whether or not the air conditioner 24 is operating. If the air conditioner 24 is not operating, the process proceeds to step 35. In step 35, the intake air temperature is changed from the solid line in FIG. The particulate collection time H is set by reading the reduction rate of the reference collection time Ho corresponding to, and the routine proceeds to step 36.

If the air conditioner 24 is operating in step 34, the process proceeds to step 37, and in step 37, the reference collection time Ho corresponding to the intake air temperature is drawn from the broken line in FIG.
By reading the reduction ratio of, the particulate collection time H is set, and the routine proceeds to step 36.

In step 32, it is determined that the vehicle is stopped by the output of the vehicle speed sensor, the parking position of the shift lever detected by the shift lever position detection device of the transmission, the output of the parking brake operation detection device, or the like. If the engine is detected and therefore it is determined that the engine is idling, the routine proceeds to step 38, where it is checked whether or not the air conditioner 24 is operating in the same manner as described above, and the air conditioner 24 is operating. If not, the routine proceeds to step 39, at which the particulate collection time H is set to a fixed collection time H1 and the routine proceeds to step 36.

If the air conditioner 24 is operating in step 38, the process proceeds to step 40. In step 40, the particulate collection time H is set to a fixed collection time H2 and the process proceeds to step 36.

At step 36, the particulate collection times are integrated by the filters 15 and 16 and the process proceeds to the next step 41. At step 41, the integrated value of the particulate collection time is calculated by the reduction factor as the reference collection time. It is checked whether or not the set collection time H corrected from the time Ho or the set collection time H1 or H2 is reached, and if the set collection time is not reached, the process returns to step 30 and The routine is repeated, but when the integrated value reaches the set collection time, the routine proceeds to step 42, where the valves 6 and 7 are opened and closed and the filters 15 and 16 are regenerated as described above.

As described above, the filters 15 and 16 of the trap devices 8 and 9 have a high intake air temperature and a low air conditioner operation.
Appropriate particulate collection time H is set in accordance with the non-operation and the running or stopping of the vehicle, and therefore, the particulate collection amount by the filters 15 and 16 is adjusted to a substantially constant appropriate amount. Therefore, stable regeneration of the filters 15 and 16 is facilitated, and particulates can be reliably removed from the exhaust by the trap devices 8 and 9 for a long period of time.

In the above embodiment, the increase / decrease correction of the reference collection time is carried out stepwise according to the level of the intake air temperature, but this is linearly or curved steplessly as necessary. It is also possible to control to perform the same increase / decrease correction, and to appropriately adjust the increase / decrease correction amount of the particulate collection time due to the operation or non-operation of the air conditioner according to the magnitude of the operation load. Needless to say.

[0027]

In the exhaust particulate removing device according to the present invention, the time for trapping particulates by the trapping device is always set to an appropriate length according to the operating condition of the vehicle and the particulates are removed by the regenerating means. Since the amount of particulate collection at this time is always adjusted to an appropriate amount, efficient regeneration is performed, overheating of the trap device during regeneration is reliably prevented, and the occurrence of cracks and melt damage is suppressed, The engine exhaust can be stably purified over a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic layout diagram in an embodiment of the present invention.

FIG. 2 is an explanatory view of control of the above embodiment.

FIG. 3 is a control system diagram of the above embodiment.

[Explanation of symbols]

 1 Diesel Engine 8 Trap Device 9 Trap Device 15 Filter 16 Filter 17 Electric Heater 18 Electric Heater 24 Air Conditioner 25 Switch 26 Controller 27 Temperature Sensor

Claims (6)

[Claims] 1. A trap device for collecting fine particles in engine exhaust, a regenerating unit for removing fine particles collected by the trap device at every set collection time, a temperature sensor for detecting an intake temperature of the engine, An exhaust particulate removal device having vehicle stop detection means for detecting a stop of a vehicle equipped with an engine, and correction means for correcting the set collection time by the output of the temperature sensor and the vehicle stop detection means. 2. The exhaust particulate removal device according to claim 1, wherein the correction means shortens the set collection time as the intake air temperature detected by the temperature sensor is higher. 3. The set collection time according to claim 1 or 2, wherein when the stoppage of the vehicle is not detected by the vehicle stop detection means, the set collection time is corrected according to the intake air temperature detected by the temperature sensor. Exhaust particulate removal configured to prevent the correction of the set collection time according to the intake air temperature detected by the temperature sensor when the stop of the vehicle is detected by the vehicle stop detection means apparatus. 4. The exhaust particulate removal device according to claim 1, wherein the vehicle stop detection means is a vehicle speed sensor. 5. The exhaust particulate removal device according to claim 1, wherein the vehicle stop detection means is a shift lever position detection device or a parking brake operation detection device. 6. The air-conditioning operation detecting means for detecting the operation of the vehicle air conditioner according to claim 1, wherein the air-conditioning operation detecting means detects the operation of the air conditioner. An exhaust particulate removal device configured to shorten the set collection time as compared to when the air conditioner is not operating.