JPS60108515A - Fine particle trapping device in exhaust gas from internal-combustion engine - Google Patents

Abstract

PURPOSE:To surely prevent trouble due to misfiring of a burner, by avoiding starting of operation of the burner until the temperature of engine cooling water exceeds a predetermined value even though a predetermined time elapses from the starting of the engine. CONSTITUTION:A control device 43 judges upon whether the regeneration of a trap 34 is necessary or not in accordance with the inlet pressure value VR1 of the trap 34 and the outlet pressure value VR2 of the same, and actuates a trap regenerating burner 35 when the judging is made such that the regeneration of the trap 34 is necessary. A water temperature sensor 51 detects the temperature of engine cooling water, and a timer starts its operation by a turning on signal from an engine starting switch 50 and counts the elapse time from the starting point of the engine. The control device 43 maintains the burner 35 in its rest condition other than the case that the temperature of cooling water is higher than a predetermined value and the elapse of time from the starting of the engine exceeds a predetermined value.

Description

Detailed Description of the Invention Technical Field The present invention relates to an exhaust particulate collection device used as an exhaust purification device for an internal combustion engine, and more specifically to a burner provided for regenerating a trap for collecting exhaust particulates. The present invention relates to a control device.

<Prior art> As a conventional type exhaust particulate collection device, the
There is one described in Japanese Patent No.-115809.

This system collects particulates contained in the exhaust by installing a trap in the exhaust passage, and also detects the particulate collection status of the trap based on the exhaust pressure on the inlet and outlet sides of the trap. However, when it is determined that it is necessary to regenerate the trap, a trap regeneration burner installed in the exhaust passage upstream of the trap is operated for a predetermined period of time.

However, in such conventional exhaust particulate collectors, when it is determined that the trap is in the regeneration period,
For example, because the burner was configured to operate immediately without considering other conditions such as exhaust temperature, even when the exhaust temperature and exhaust system temperature are low, such as immediately after a side start operation, the trap may be in the regeneration period. If this is determined, the burner may operate, causing various inconveniences.

In other words, when the exhaust temperature and the temperature of the exhaust system are low, the ignitability of the burner may be poor, and even if the burner ignites, the temperature rises slowly and the particulates collected in the trap are not incinerated, causing the burner to ignite. The supplied fuel may be discharged unburned.

Therefore, in order to eliminate the inconvenience caused by the fuel supplied to the burner being discharged unburned,
A patent application filed in 1982 provides a control device that prevents the burner for trap regeneration from operating until the exhaust system is sufficiently warmed up, and until a predetermined period of time has elapsed from the start of the engine.
It was previously proposed as No. 24833.

This is constructed as shown in Fig. 1. A trap case 2 is interposed in the exhaust passage 1 of a diesel engine, and a honeycomb type trap 4 is installed inside the trap case 2 via a buffer material 3. It is designed to collect fine particles in the exhaust gas.

A burner 5 for regenerating the trap is installed in the trap case 2 upstream of the trap 4, and the burner 5 receives the fuel discharged from the electromagnetic fuel injection valve 6 and the air discharged from the air pump T. is supplied. 8 is a fuel pump that supplies fuel from a fuel tank (not shown) to the injection valve 6, and 9 is a glow plug.

Further, a control device for controlling the fuel pump 8, fuel injection valve 6, air pump 7 and glow plaque 9 [10 includes an inlet side pressure sensor 11 for detecting the exhaust pressure VP1 at the inlet portion of the trap 4, and an outlet side pressure sensor 11 for detecting the exhaust pressure VP1 at the inlet portion of the trap 4. outputs are supplied from an outlet side pressure sensor 12 that detects the exhaust pressure VP2, an inlet temperature sensor 13 that detects the inlet temperature T1 of the trap 4, and an outlet temperature sensor 14 that detects the outlet temperature T2 of the trap 4. At the same time, by supplying the output of the engine key switch 15, the battery 16 is connected to the control device 1.
0, the power supply voltage VB was applied.

The control device 10 is constructed as shown in FIG. 2, and includes a timer 17 that starts counting when the lateral start movement switch is turned on, and a timer 17 that starts counting after a predetermined time period counted by the timer 17 has elapsed. , a regeneration time detection means 18 that detects whether or not the trap 4 has reached the regeneration time based on the outputs VPt and VF6 of the two positive force sensors 11 and 12, and outputs a regeneration start signal when it is the regeneration time. , output control means 1 for outputting an activation signal for the burner 5 when receiving the regeneration start signal output from the regeneration timing detection means 18;
9, and a reproduction stop means 2° for detecting the reproduction stop time and outputting a reproduction stop signal to the output control means 19.

According to such a device, the timer 17 starts measuring time from the time when the engine is started, and the timer 17 starts measuring time from the time when the engine is started.
After 0 has elapsed, a detection start signal is supplied to the reproduction timing detection means 18. Therefore, until a predetermined time has elapsed after the engine is started, no matter how many particles are collected in the trap 4 and the regeneration time has arrived, regeneration will not start, and the Various troubles are avoided.

However, if regeneration is simply set to wait until a predetermined time has elapsed from the time the engine is started, for example, it is necessary to set the standby time to match the cold start, where the burner's ignitability is the worst. Therefore, when the temperature of the exhaust and exhaust system rises relatively quickly, such as during a hot restart, even though the temperature of the exhaust and exhaust system quickly reaches conditions suitable for burner operation, On the other hand, if the standby time was adapted to a hot restart, the burner would start operating too early during a cold start, resulting in poor ignition performance.

<Object of the Invention> The present invention has been made by focusing on such conventional problems, and its purpose is to prevent engine cooling water from flowing even after a predetermined period of time has passed since the engine started operating. The purpose is to prevent troubles caused by poor ignition of the burner by forcing the burner to wait until the temperature rises above a predetermined temperature.

<Structure of the Invention> In order to achieve the above-mentioned object, in the present invention, as shown in FIG. 3, the trap inlet side pressure VPI and outlet side pressure P
a regeneration time detection means that determines whether or not there is a need to regenerate the trap based on 1; and a burner that operates a trap regeneration burner when the regeneration time detection means determines that regeneration is necessary. An exhaust particulate collection device for an internal combustion engine comprising a control means, a timer that starts operating in response to an on signal from an engine start switch and measures the elapsed time from the time the engine is started, and a timer that detects the engine cooling water temperature. Based on the water temperature sensor, the output of the timer, and the output of the water temperature sensor, the regeneration timing detection means is disabled unless a predetermined value or more has elapsed since the start of the engine and the cooling water temperature is above the predetermined value. The burner is configured to include water temperature detection means for fixing the operating state and keeping the burner in an inactive state.

<Example> The present invention will be explained in detail below.

In the first embodiment shown in FIG. 4, a trap case 32 is interposed in the exhaust passage 31 of the engine, and a trap 34 having a honeycomb structure is housed inside the trap case 32 with a buffer material 33 interposed therebetween. .

Note that some of the honeycomb holes of the trap 34 are opened on the inlet side and closed on the outlet side, and the other holes are closed on the inlet side and opened on the outlet side, so that the exhaust air is directed to the wall of the hole. Particulates contained in the exhaust gas are collected as it passes through the exhaust gas.

Moreover, the trap 3 inside the trap case 32
A burner 35 for trap regeneration is housed in the upstream portion of the trap. This burner 35 includes a combustion tube 36 with a large number of exhaust gas introduction holes 36a formed in the Jl wall, a backflow type evaporator tube 3T with a fire outlet 37a located inside the combustion tube 36, and this evaporator tube 37. It is configured to include a mixture introduction pipe 3B facing inside the combustion tube 36, and an ignition glow plug 39 facing the vicinity of the flame spout 37a of the evaporation tube 37 inside the combustion tube 36.

An electromagnetic fuel injection valve (
A fuel injector 40 is provided, and fuel (same as engine fuel, for example, light oil) is introduced to the fuel injection valve 40 from a fuel tank (not shown) by an electromagnetic fuel pump 41. Further, a discharge port of an air pump 42 is connected to the middle of the mixture introduction pipe 3B to supply air to the mixture introduction pipe 38. Therefore, the operation of the burner 35 depends on the operation of the fuel pump 41, fuel injection valve 40, and air pump 42.
and by operating the glow plug 39.

The above-mentioned fuel pump 41, fuel, f+ injection valve 40, and air pump 42 are operated by signals from a control device 43. Further, the glow plug 39 is energized from the battery 44 via a normally closed relay 45, and this relay 45 is connected to the control device 4.
3. - Closed by a signal from.

Here, an inlet side pressure sensor 46 for detecting the inlet side pressure P1 of the trap 340 is provided in the trap case 32 upstream of the trap 34 and υ downstream of the burner 35, and an inlet side pressure sensor 46 is provided inside the trap case 32 downstream of the trap 34 υ. is provided with an outlet side pressure sensor 4T for detecting the outlet side pressure P2 of the trap 34. Then, the output voltage vp1. of these pressure sensors 46, 47. By supplying the respective signals vp2 to the control device [43], the regeneration timing of the trap 34 is determined based on these signals.

On the other hand, an inlet side temperature sensor 48 is provided in the trap case 32 upstream of the trap 34 and downstream of the burner 35 to detect the temperature T1 of the exhaust gas flowing into the trap 34 (inlet side temperature). Inside the trap case 32 downstream of the trap 34 is an outlet side temperature wave sensor 49 that detects the temperature (outlet side temperature) T2 of the exhaust gas flowing out from the trap 34.
is attached. These temperature sensors 4B and 49 are configured by a pair of CA@i[, for example, and their output pressure v
T1vT2 is supplied to the control device 43. Note that the output voltage vT1 of the inlet side temperature sensor 48 is used to control the fuel injection amount to the burner 35, and the output voltage vT2 of the outlet side temperature sensor 49 is used to determine whether to stop regeneration. 50 is an engine key switch, and power supply voltage VB is applied from the battery 44 to the control device 43 via this switch 50.

Here, in the present invention, a water temperature sensor 51 that detects the engine cooling water temperature (hereinafter referred to as water temperature) is provided, for example, in the thermostat housing 52, and its output voltage VTw is supplied to the control device 43.

At the same time, a rotation sensor 5 composed of an electromagnetic pickup, etc.
The pulse signal Rev output from the load sensor 3 and the voltage VJ output from the load sensor 54 are supplied to the control device 43. Note that the load sensor 54 is attached to a fuel injection pump 55 that pumps fuel to a fuel injection nozzle provided in a combustion chamber of the engine, and is attached to a control lever 55a of this injection pump 55.
The engine load is detected from the o position t (rotation phase).

The control device [43 is configured as shown in FIG.
When the key switch is turned on, the timer 60 starts counting time based on the processing signal Vr of the rotation sensor 53 when the engine is started (when the rotational speed of the engine reaches, for example, 500 rpm or more). When the predetermined time 1 (,) has elapsed, a timing end signal is output.The predetermined measurement time of this timer 60 is 1 (, hooray). After the IJ start, the exhaust system of the engine is sufficiently warmed up. The time required for (
For example, about 4 minutes).

The water temperature detection circuit 61 detects the water temperature from the output voltage VTw of the water temperature sensor 52 when the timer 60 outputs the time measurement end signal, and sends a regeneration timing detection start signal on the condition that the water temperature reaches a predetermined value. Output. Also, the water temperature detection circuit 61 outputs the regeneration timing detection start signal from the timer 6.
0 is the case where the predetermined time tQ has been counted and the water temperature Tw has reached a temperature (for example, about 60° C.) that corresponds to a state where the exhaust system is sufficiently warmed up.

The regeneration time detection circuit 62 starts detecting the regeneration time of the trap 34 based on the regeneration time detection start signal, and processes the output voltage vP1 of the input side pressure sensor 46 and the output side pressure sensor VP2. It determines whether or not it is necessary to regenerate the trap 34, and outputs a regeneration start signal when it is determined that the regeneration time has come, but outputs a regeneration wait signal when it is determined that the regeneration time has not been reached. .

Further, the output control circuit 64 receives each of the above signals and operates or stops the burner 35 in a predetermined time order.
Next, the fuel pump 41, fuel injection valve 40, and air pump 42 are operated, and the injection amount of the fuel injection valve 40 is also controlled.

That is, the processed signal v1 of the rotation sensor 53 and the load sensor 54
The rotational speed and load of the engine are detected based on the output signal Vl of the engine, and a drive signal having a predetermined pulse width according to the operating state is output. Thereafter, the fuel injection amount is controlled by correcting the pulse width of the drive signal based on the output voltage vT1 of the inlet temperature sensor 4B and also based on the level of the inlet temperature T1.

The regeneration stop circuit 63 stops the regeneration of the trap 34 after starting regeneration when a regeneration wait signal is output from the regeneration timing detection circuit 62 because the exhaust particulates are not collected in the trap 34 enough to require regeneration. When a predetermined time (for example, about 100 minutes) necessary for A regeneration stop signal is output to stop the operation of the burner 35, or to continue to stop the operation of the burner 35.

Fig. 6 shows a control device 43 using a microcomputer.
All specific examples are shown below.

In FIG. 6, a control device [43] includes a constant voltage circuit 65 that converts a power supply voltage VB output from a battery 44 into a constant voltage Vcc to be supplied to each component to be described later, and a CPU.
In addition to 66, memory (ROM) 137 and PIO (peripheral I/Q) 71 for interface, 2
The outputs of the pressure sensors 46 and 47 [pressure VP1. VF6
Output voltage VT1 of 2 O temperature W cents t48 and 49
．． VT2, the output voltage Vr of the converter 68 to which the pulse signal output from the rotation sensor 53 is supplied, the output voltage Vl of the load sensor 54, and the output voltage VTa of the water temperature sensor 51 are input, and these signals are The input side is provided with a multiplexer 69 that selects and outputs one data, and an A/P converter 70 that converts the analog data selected by the multiplexer 69 into digital data.

Note that the CPU 56 instructs the multiplexer 69 to channel via the PIQ 71, and inputs the converted data when the A/D converter TO outputs an EOC (End of Conver) signal indicating the end of conversion. It looks like this.

Also, a grounding device T2 is provided on the output side, but this grounding device f
t72 is a switching circuit 72a inserted in the ground wire of the fuel injection valve 40, a switching circuit 72b inserted in the ground wire of the fuel pump 41, a switching circuit 72C inserted in the ground wire of the air pump 42, and a glow plug. Switching circuit 7 inserted in the ground wire of the coil of relay 45
2d, but these switching circuits 728 to 72d are mainly constructed using transistors, and when a signal is supplied to each from the CPU 65 via the PIO 71, each ground wire is made conductive and the burner is switched on. It is designed to operate each device for 35.

Next, the operation will be explained according to the flowchart shown in FIG.

First, the Sl reads the voltage Vr output from the rotation sensor 53 via the F/V converter 68, and determines whether the engine has started (for example, the engine rotation speed is 50 Orpm), If NO, stop the operation of the burner 35 at 815, or continue to stop it and return to Sl.
If +a, proceed to S2. In S2, it is determined whether a predetermined time (for example, 4 minutes) has elapsed since the engine started (the exhaust system has been sufficiently warmed up and the temperature is suitable for igniting the burner 35), and if NO In step 815, the operation of the burner 35 is stopped or continues to be stopped, and the process returns to S1 (9), and if Yes, the process proceeds to S3. In S3, it is determined whether or not the burner 35 is in operation, and if Yes, proceed to 1l-j: S7,
If No, proceed to S4.

In S4, the output voltage VTw of the water temperature sensor 51 is read,
It is determined whether or not the water temperature Tw is higher than a predetermined value (for example, the temperature of the exhaust system is suitable for igniting the burner 35, such as 60° C.), and if NO, in 815, the burner 35 is
Stop or keep stopping the working pipe and return to Sl fi, Y
In the case of es, the process advances to S5. In S5, pressure is calculated in order to detect the state of collection of particles in the trap 34. In other words, the honeycomb type trap has the characteristics of a laminar flow meter, and if the amount of collected particles is constant, the trap 34 population side pressure P1 is proportional to the exhaust flow rate (proportional to the gas flow).
and the differential force ΔP between the inlet side pressure pi and the outlet side pressure P2 = P1
-P2 is linearly proportional, and the ratio ΔP/J of Pll and ΔP
? l remains constant. Therefore, the difference between the output voltages of the inlet and outlet pressure sensors 46 and 47 when the collected amount of exhaust particulates reaches a predetermined value (+iK) ΔVP=VP1−VP2(
Hereinafter referred to as ΔVPmax) is the inlet side pressure sensor 46
It changes according to the output voltage vP1 of , and is obtained by the following equation.

ΔVPmax=A@VP1-B (A and B are constants)
Therefore, S5 sets ΔVPmax to
Proceed to the actual ΔVP += VPI −VF6 is ΔV
Pmax) Determine whether it is large or not, and if NO, set 81
5, continue to stop burners 3 and 5, return to Sl, and select Yes.
In this case, it is determined that regeneration is necessary, and the process proceeds to S9, where the burner 35 is ignited. Incidentally, when YES in S3, that is, when the burner 35 is already in operation, the process proceeds to 87 and determines whether or not the burner 35 is burning stably.
If YES, proceed to S11; if NO, proceed to S8.

In S8, it is determined whether or not the burner 35 is ignited, and Y
If es, the process proceeds to 810, and if NO, the process proceeds to S9 to continue the ignition operation of the burner 35. That is, if it is determined in S6 that regeneration is necessary, and if the ignition operation is not completed, the ignition operation is performed in 89.

For details, as shown in the flowchart shown in FIG.
Close the glow plug relay 45 with a and close the glow plug 3
9 is activated, and in the next step S9b, it is determined whether the elapsed time since the glow plug 39 was turned on has reached a predetermined value (for example, 50 seconds), and the step is NO.

In this case, the control returns to Sl and raises the temperature of the glow plug 3B to the temperature required for ignition. If Yes, next 89c
Proceed to step 89e to determine whether the output voltage vT1 of the inlet side temperature sensor 48 provided upstream of the trap 34 immediately before ignition of the burner 39 (immediately before supplying the burner 39) is stored, and if YES, proceed to step 89e. If NO, proceed to 89d, and this S9d
Then, the output voltage VT1 of the inlet side temperature sensor 48 is stored as the trap inlet exhaust gas temperature l1lo.

Next, in S9e, the air pump 42 is operated to start supplying air, and in S9f, the fuel pump 41 is operated. 89g
Then, based on the rotational speed Vr and load Vl at that time, search for a drive signal with a dignity ratio set in advance according to these values, and select the drive signal from the need for increase correction to facilitate ignition with SGH. For example, the signal is multiplied by 2, and this drive signal is output at 891 to operate the fuel injection valve 40 and start supplying fuel.

As a result, a mixture of air and fuel is ejected from the mixture introduction pipe 3B of the burner 35, flows inside the reverse flow type evaporator tube 3T, and is sent into the combustion tube 36 through the flame jet port 378. It is ignited by the heat of the glow plug 39. Then, it is combusted while being mixed with the exhaust gas introduced from the numerous exhaust gas introduction holes 38a of the combustion tube 36.

89j, when calculating the difference between the current exhaust temperature T1 after the start of fuel supply and the exhaust temperature To immediately before the start of fuel supply,
The output voltage vT1 of the inlet side temperature sensor 48 is read and stored in 89c as described above.
Temperature difference JVT1 = VTl - VTo 89
Proceed to k.

In step 89, it is determined whether the temperature difference ΔVTl is greater than or equal to a predetermined value (
If it is NO, go to 891 and determine whether a predetermined time (for example, 10 seconds) has elapsed after the start of fuel supply.If NO in 89J, go back to Sl. Repeat the ignition judgment. 81 when the temperature difference does not decrease beyond the predetermined value even after the predetermined time has elapsed (when 891 is YesO)
Proceed to Step 5 to stop the operation of the burner 35 and return to Sl.

Note that if YES in S9J, it is assumed that ignition has been completed and the process proceeds to S10.

At 810, it is determined whether or not the inlet side temperature T1 has reached a predetermined value (stable combustion temperature of the burner 35, e.g. 500°C).
For example, it is determined whether 40 seconds) have elapsed. If the result of this determination is NO, the process returns to Sl and repeats the temperature measurement, but if YES in 814 (when the stable combustion temperature has not been reached even after a predetermined period of time has elapsed), the process proceeds to 815 and the burner 3
Stop the operation and return to Sl.

If 810 is Yes, that is, the burner 35 is
When the stable combustion temperature reaches the stable combustion temperature of
Proceed to ll.

In all, the fuel supply amount is controlled so that the temperature is suitable for regeneration of the trap 34, and in 812, the temperature T2 at the outlet of the trap 34 is determined from the output voltage vT2 of the outlet side temperature sensor 49.
is the bath loss prevention limit temperature of the trap 34 (e.g. 900°C)
It is determined whether or not this has been reached, and if Yes, the operation of the burner 35 is stopped even in the middle of regeneration and the process returns to Sl. N
In the case of o, it is determined in 813 whether a predetermined time (for example, 10 minutes) has elapsed since the playback was started, and the
In this case, the process returns to 81 and the trap 34 is regenerated for a predetermined period of time. When 813 becomes Yes after a predetermined period of time has elapsed, 8
15, the operation of the burner 45 is stopped.

The temperature control performed in step 811 described above is performed according to the flowchart shown in FIG.

First, in 8111, the rotational speed Vr and load Vl at that time
511b reads the output voltage vT1 of the inlet side temperature sensor 48 and determines whether the exhaust temperature is equal to or higher than the regeneration lower limit temperature (for example, 550° C.). do. As a result of this determination, if the temperature is below the regeneration lower limit temperature, the process proceeds to s11k to continue operating the glow plug 39. In addition, during playback, 5
The glow plug 39 is also operated when the temperature drops below 550°C during regeneration after the temperature reaches 50°C or higher and the glow plug 390 operation a'e is stopped.

Next, proceed to 5IIJ and correct the drive signal by increasing it by, for example, 1°6 times, and calculate the activation time of the glow plug 39 at 511m, or the time since the temperature drops below the regeneration lower limit temperature (550°C), or at 810m after the ignition operation. 55 after the temperature exceeds 500℃
It is determined whether the time for which the temperature remains below 0° C. has reached a predetermined value, for example, 15 seconds, and N.

In the case of , the process proceeds to 5lln, where a drive signal is output, the fuel injection valve 40 is operated, and the process proceeds to 812 in FIG.

In addition, if Yes at 511m, 8.
Step 15, the operation of the burner 35 is stopped.

On the other hand, when it is determined in 811b that the trap 340 inlet exhaust gas temperature T1 is equal to or higher than the regeneration lower limit value (550°C),
After proceeding to 811C and stopping the operation of the glow plug 39, the amount of fuel supplied is controlled according to the exhaust temperature based on the determinations at 5lld, 5lle, and 5llf. That is, the temperature suitable for regenerating the trap 34 is 600°C or higher,
If the temperature is lower than 600°C, the amount of fuel is increased, and if the temperature is higher than 600°C, the amount of fuel is decreased to save fuel or to prevent burnout of the trap 34. For this purpose, the 511d first determines whether the temperature is, for example, 580°C or higher, and if it is less than 580°C, the drive signal is increased by, for example, 1.4 times in s 11 h, and the 511n is
Proceed to. If it is determined that the temperature is 600°C or higher in 5lle, it is determined in 511r whether the temperature is 620°C or higher, and if it is less than 620°C, it is the optimum temperature, so 51
The process proceeds to step 5110 without correcting the drive signal as in step 1j. If the result of the determination at 511r is 620° C. or higher, the drive signal is reduced by, for example, 0.8 times at 811g, and the process proceeds to 5lln. Then, the fuel injection valve 40 is operated by outputting these drive signals at 5lln. In this way, in order to maintain the temperature of the exhaust gas within a temperature range suitable for regeneration of the trap 34, the drive signal for the fuel injection valve 40 is corrected to increase or decrease according to the exhaust gas temperature T1 of the trap 34. Such an operation is performed because as a result of the determination in 812, the exhaust gas temperature KT2 at the outlet of the trap has not risen above the limit, and furthermore, in 81
If it is determined in step 3 that the playback time is within, the process is repeated.

Further, the operation of the burner 35 is stopped at S15 as shown in the flowchart shown in FIG. 10, and first, at 515a, the operation of the glow plug 39 is stopped.

Then, at 515b, the operation of the fuel pump 41 is stopped,
At step 515c, the operation of the fuel injection valve 40 is stopped to stop the supply of fuel. Thereafter, at 815d, the operation of the air pump 42 is stopped and the supply of air is also stopped.

FIG. 11 is a functional block diagram corresponding to a second embodiment of the present invention, in which the output signal V of the water temperature sensor 51 is
Tvi> and the water temperature Tw are detected, and when the burner 35 is activated, the operating time of the glow plug 39 is predetermined according to the water temperature, and the increase correction magnification M of the drive signal of the fuel injection valve 40 at the time of ignition is determined.
By providing an ignition operation control circuit 73 that calculates
Glow plug 3 during ignition operation via output control circuit 64
9 and the fuel injection valve 40 are controlled. The other parts are the same as those of the first embodiment described above, so the explanation will be omitted.

In this second embodiment, as shown in FIGS. 12 to 14, the ignition operation is performed according to the 7t70-chart by partially changing the flowchart shown in FIG.

That is, first, a preheating operation is performed at 89a.

This is carried out as shown in FIG. 13, in which the glow plug relay 45 is closed to operate the glow plug 39 in step 89a-1, and it is determined in step 89a-2 whether or not preheating is sufficient. If yes, go to 89c, if no, go to 89
Proceed to g-3. In 89a-3, the output voltage VTw from the water temperature sensor 51 is stored, and in 89a-4, the necessary preheating time t1 of the glow plug determined according to the water temperature Tw is retrieved from vTo, and then the process proceeds to 89b.

In S9b, it is determined whether the elapsed time t from the start of preheating of the glow plug 39 to the present has reached the required preheating time t1 according to the current water temperature Tw, and if the result is No, Sl If the answer is Yes, it is determined that preheating has been completed and the process proceeds to S9c.

Note that the required preheating time t1 described above is long when the water temperature Tw is low (the exhaust system has not been sufficiently warmed up), and the water temperature Tw is long.
The higher w is (the exhaust system has been sufficiently warmed up), the shorter the time is set. Incidentally, Tw≦40℃～TW≧
In the range of 80°C, tl can be 60 sec to 49 sec.

Further, in S9c-89g, the process shown in FIG. 8 (same as in the case of the first embodiment) is performed, and in 89h, tank lid correction at the time of ignition is performed. In detail, as shown in Figure 14, sgh-
In step 1, it is determined whether the search for the increase correction magnification M of the drive signal has been performed, and if YES, the process proceeds to sgh-4 and the drive signal of the fuel injection valve 40 is multiplied by iM, but if NO, then At 89h-2, the output voltage VTw f of the water temperature sensor 51 is memorized, and at 59h-3, the magnification IQ according to the water temperature Tw is searched from VTw, and the process proceeds to S91 via 59h-4, and the subsequent steps are the same as in the case of FIG. Proceed to.

In this way, when the burner 35 is operated, the preheating time of the glow plug 39 and the fuel supply amount are controlled according to the water temperature (the warm-up state of the exhaust system), so in the case of the second embodiment, the ignitability of the burner 35 is improved. 1) The magnification M at the time of ignition is the water temperature T.
For example, at 40°C or lower, Fi is twice as large, but at 80°C or higher, it becomes 1.6 times larger.

FIG. 15 is a functional block diagram corresponding to the third embodiment of the present invention. During engine operation, the outlet temperature T2 of the trap 34 changes based on the output voltage vT2 of the trap outlet side temperature sensor 49. A case where a regeneration stop signal is sent from the regeneration stop circuit 63 to the output control circuit 64 by reaching the erosion prevention limit temperature (for example, 900° C.);
A determination circuit T4 is provided to determine whether the operation of the other burners 35 is stopped. This discrimination circuit γ4 causes the operation of the glow plug 39, the supply of fuel, and the supply of air at the same time when T2 reaches the melting prevention limit temperature and the operation of the burner 35 is stopped through the operation of the output control circuit 64. After stopping the burner 35, the burner 35 is not restarted after a predetermined period of time (for example, 5 minutes);
When the operation of 5 is stopped, the glow plug 39 is activated,
After simultaneously stopping the fuel supply, the air supply is stopped after a predetermined period of time (for example, 2 minutes). The other parts are shown in FIG. 11 and are the same as the second embodiment, so their explanation will be omitted.

In this third embodiment, as shown in FIG.
The burner stopping operation is performed according to the flowchart shown in the figure.

That is, after stopping the operation of the glow plug 39 and the fuel supply in steps 815a to 815c, it is determined in step 515d whether or not T2 has reached the trap 340 melting prevention limit temperature (900° C.), and the answer is Yes. If , return to SL,
If no, return to 815.

If NO in 815d, that is, if T2 has not reached 900°C, proceed to 515g and determine whether the predetermined time (2 minutes) has been reached, and if Yes, stop the operation of the air pump 42 in s15+. and return to SL. If NO at 815g, proceed to 515h to determine whether the engine is continuously operating (started), and if NO, proceed to 815i.
In the case of s, the process returns to 815a.

In this way, T2 is delayed to the melting limit temperature of the trap 34 f
In case c, all operations of burner 35 are stopped and trap 3
Since the burner 35 is not operated until the time required for the trap 4 to cool down sufficiently has elapsed, even if the trap 34 is insufficiently regenerated and requires regeneration, damage to the trap 34 is reliably prevented. can. On the other hand, when T2 does not reach the melting eye temperature of the trap 34 and the operation of the burner 35 is to be stopped, the operation of the glow plug 39 and the supply of fuel are stopped at the same time, and then the supply of air is stopped after a predetermined period of time. As a result, the scavenging performance is improved by the blown air, and the unburned fuel accumulates in the mixture introduction pipe 38.
It is also possible to prevent deposits from being baked by the exhaust heat and clogging the passage.

<Effects of the Invention> As explained above, according to the present invention, after a warm start of the engine, the exhaust system is warmed up after a predetermined period of time has elapsed, and when the water temperature is lower than the exhaust temperature. Since the burner is configured to operate only when the system reaches a predetermined temperature indicating a sufficiently warmed-up state, it will always operate only in conditions suitable for ignition, regardless of temperature conditions, and the burner's ignition performance will be reduced. It has very good performance and can prevent misfires and save fuel. In other words, if the exhaust system warms up relatively quickly after a warm start or in a warm region, the burner will start operating earlier, and even if the exhaust system is easily cooled in a cold region, it will always be suitable for igniting the burner. The burner can be operated under the following conditions. Furthermore, in conjunction with preventing misfires, it is also possible to prevent unburned fuel from being released into the atmosphere together with exhaust gas. Furthermore, since the time spent waiting for the burner to start operating can be minimized, the regeneration timing of the trap will not be significantly delayed, and the impact on fuel efficiency due to the increase in exhaust pressure due to delayed regeneration can be minimized. It has some special features.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional example, Figure 2 is a block diagram as well,
FIG. 3 is a block diagram corresponding to the configuration of the present invention, FIG. 4 is a configuration diagram of the first embodiment of the present invention, FIG. 5 is a block diagram of the mounting section, and FIG. 6 is a configuration diagram of the control device. , Figure 7~
FIG. 10 is a flowchart, FIG. 11 is a block diagram of the main part of the second embodiment of the present invention, FIGS. 12 to 14 are flowcharts, and FIG. The block diagram of the section, FIG. 16, is also a flowchart. 31...Exhaust passage 32...Trap case 34.
...Trap 35...Burner 43...Control device 46...Inlet side pressure sensor 4T...Outlet side pressure sensor 48...Inlet side temperature sensor 49...Outlet side temperature sensor 51...Water temperature Sensor 52...Thermostat housing 60...Timer 61...Water temperature detection circuit 62...Regeneration timing detection circuit 64...Output control circuit Patent applicant Nissan Motor Co., Ltd. Agent Patent attorney Fujio Sasashima No. 13 Figure 14

Claims (1)

[Claims] A trap for collecting exhaust particulates installed in the exhaust passage, a burner for regenerating the trap installed in the exhaust passage upstream of the trap, and a trap for collecting particulates based on the exhaust pressure on the inlet and outlet sides of the trap. Exhaust particulates comprising: a regeneration time detection means for detecting the entire collection state and determining the safety of drug regeneration; and a burner control means for operating a burner when it is determined through the regeneration time detection means that regeneration is necessary. The collection device includes a timer that starts counting from the time the engine starts, a water temperature sensor that detects the cooling water temperature of the engine, and a water temperature sensor that detects the temperature of a predetermined value or more from the start of the engine based on the output of the timer and the output of the water temperature sensor. water temperature detection means for fixing the regeneration time detection means to a non-operating state and maintaining the burner non-operation state unless time has elapsed and the cooling water temperature is equal to or higher than a predetermined value; An exhaust particulate collection device for an internal combustion engine, characterized by: