JPS5915619A - Processing device of exhaust fine particle in internal-combustion engine - Google Patents

Abstract

PURPOSE:To accurately control a quantity of fuel supplied to a burner in accordance with a required amount of fuel, by controlling both the quantity of fuel supplied to the heating burner and ignition timing of the burner through the signal of an engine load and engine speed. CONSTITUTION:An engine speed signal 1S1 of an engine speed detector 21 and an accelerator position signal 1S2 of an accelerator position sensor 22 detecting a depressive amount of an accelerator pedal are input while a difference pressure signal 1S3 of a difference pressure sensor 9, temperature signal 1S4 of a temperature sensor 11 in the upstream side and a temperature signal 1S5 of a temperature sensor 12 in the downstream side are respectively input to a controller 20. On the basis of these input signals 1S1-1S5, the controller 20 outputs a control pulse signal OS1 of a solenoid opening and closing valve 6 and an ignition signal OS2 output through an ignition coil 13 to an ignition plug 5d.

Description

Detailed Description of the Invention The present invention collects particulates contained in the exhaust gas of an internal combustion engine in a trap, operates an exhaust heating burner provided upstream of the trap, and recycles the particulates collected in the trap. The present invention relates to an exhaust particulate treatment device for an internal combustion engine that performs combustion processing.

In order to prevent particulates such as carbon contained in the exhaust gas of an internal combustion engine from being released into the atmosphere, it is known that a trap is provided in the exhaust system and the particulates are filtered and collected by the trap. At this time, the particulates collected in the trap may not only increase the filtration resistance of the trap, but also increase the exhaust pressure of the engine, thereby impairing the engine output and exhaust emission performance.

Therefore, in the past, an exhaust heating burner was installed upstream of the trap, and the exhaust heating burner was activated when the trap became clogged to some extent with exhaust particles, or the exhaust heating burner was activated at regular intervals using a timer. The system automatically operates the trap to re-burn the particulates collected in the trap and clear the blockage.

However, in such conventional exhaust particulate processing equipment, as shown in Utility Application No. 56-22107 or Japanese Patent Application Laid-Open No. 54-12029 filed by the present applicant, burner operation for regenerating the trap is difficult. Even if you control the timing,
The fuel IM supplied from the burner was not controlled. For this reason, a constant amount of fuel flow is supplied into the exhaust gas, so that if the oxygen concentration in the exhaust gas changes, combustion in the burner becomes unstable. In addition, even if the required fuel amount changes depending on engine operating conditions such as engine load and engine speed, the supply loss remains the same, so as shown in Figure 4, the degree of increase in exhaust temperature varies. If the trap regeneration temperature is too low or too high, it may cause inconveniences such as burnout of the trap or deterioration of fuel efficiency.

In view of such conventional inconveniences, the present invention detects the engine load and engine rotation speed, uses a control device to calculate the amount of fuel to be supplied to the exhaust heating burner based on these rain detection signals, and uses the output pulse signal of the control device to calculate the amount of fuel to be supplied to the exhaust heating burner. In response, the fuel flow rate supplied to the exhaust heating burner is controlled using an electromagnetic on-off valve, and trap regeneration timing is detected to control the activation timing of the electromagnetic on-off valve and the ignition device of the exhaust heating burner. The present invention provides an exhaust particulate treatment device for an internal combustion engine, which enables the amount of fuel supplied to the burner to be controlled with high precision according to the required amount of fuel.

Embodiments of the present invention will be described below based on the drawings.

A trap 3 for filtering and collecting fine particles such as carbon contained in the exhaust gas is provided in a trap case 2 installed in an exhaust passage 1 of a fuel-injection internal combustion engine (not shown), such as a diesel engine. The trap 3 is made of a ceramic honeycomb, and while the trap 3 is made of a ceramic honeycomb, approximately half of the honeycomb cells on the exhaust inflow side are blocked in a scattered manner, while the unoccluded honeycomb cells are blocked on the exhaust outlet side and are not blocked. Exhaust gas flowing in from the honeycomb cells is received by the adjacent honeycomb cells and passes through the ceramic wall, where fine particles such as carbon are filtered and collected.

On the upstream side of trap 3, there is 4ffl higher than the density of trap 3.
A heat retaining material 4 made of coarse honeycomb, ceramic foam, gold copper, etc. is provided. If the trap 3 directly faces the exhaust gas heating burner on the upstream side of the heat retention trap 4, the heated exhaust gas of the burner will directly hit the trap 3, and the trap will be rapidly heated, resulting in thermal damage. Therefore, by arranging the heat retaining material 4 in this manner, the heated exhaust gas from the burner does not directly hit the trap 3, and the heat retaining material buffers this. It should be noted that a shorter length in the exhaust flow direction is suitable for the heat retention benefit 4. If it is long,
This is because the larger the thermal expansion υ, the more likely thermal destruction will occur. In addition, the reason why the size of the heat retaining material 4 is increased is to eliminate the trapping effect of the heat retaining material, and by doing so, there is no combustion of particulates during trap regeneration, and the sudden increase in the heat retaining material 4 is prevented. This is because temperature rise can be prevented.

A burner 5 for heating the exhaust gas is provided upstream of the trap 3 in the trap case 2 . The burner 5 is an evaporator cylinder 5a.
, 5b, a fuel injection nozzle 5c, and a spark plug 5d, and the fuel injected from the injection nozzle 5c is vaporized by the evaporator cylinders 5a and 5b, and becomes a gas mixture with the air remaining in the exhaust gas. It is ignited by the spark plug 5d and combusts to heat the exhaust gas. The injection nozzle 5c is connected to a fuel injection pump 8 through a fuel passage 7 via an electromagnetic on-off valve 6 that controls the fuel flow rate.

The electromagnetic on-off valve 6 is shown in FIG. 3 and will be described later.
Its opening/closing duty is controlled in response to the output pulse signal of the control device 20, thereby controlling the fuel flow rate. Negative pressure passages 8a and sb connected to the upstream and downstream parts of the trap 3 are connected to a differential pressure sensor 9, which detects the differential pressure between the upstream and downstream sides of the trap 3, and detects the difference in the pressure between the upstream and downstream sides of the trap 3. Detects the degree of clogging.

Further, an upstream temperature sensor 11 and a downstream temperature sensor 12, each made of a thermocouple or the like, are provided upstream and downstream of the trap 3, respectively.

The upstream temperature sensor 11 detects whether the exhaust gas temperature on the inlet side of the trap 3 is suitable for the trap regeneration temperature.

Further, the downstream temperature sensor 12 detects the exhaust temperature on the trap outlet side in order to prevent the trap 3 from being overheated and burnt out (due to the regeneration action of the trap 3).

The control device 20 receives an engine rotation speed signal IS1 from an engine rotation speed detection device 1t-21 and an accelerator position signal IS2 from an accelerator position sensor 22 that detects the amount of depression of the accelerator pedal.
is input, and the voltage signal IS of the differential pressure sensor 9 is inputted.
5. The temperature signal ISI of the upstream temperature sensor 11 and the temperature signal IS5 of the downstream temperature sensor 12 are input. Based on these input signals IS1 to IS5, the control device 20 outputs control pulse signals 081. And ignition No. 18 os2 is outputted via the ignition coil 13 to the spark plug 5d.

Here, the electromagnetic on-off valve control pulse signal O81 calculates the engine load and engine rotation speed in the control device 20 based on the engine rotation speed signal IS1 and the accelerator position signal IS2, and adjusts the fuel flow rate supplied to the burner 5 according to these values. The electromagnetic on-off valve control pulse signal O81 and the ignition signal O82 are both an on-off duty pulse signal for the electromagnetic on-off valve 6 that controls the solenoid on-off valve 6. and a signal for controlling the activation timing of the spark plug 5d.

“Next, an example of the circuit of the control device 20 is shown in FIG. outputs the voltage signal S1.

31 is a function generator which generates the fuel injection amount Q supplied to the engine by the fuel injection pump 8 based on the values of the accelerator position signal IS2 recorded from the accelerator position sensor 22 and the engine rotational speed signal 81.
outputs a voltage signal s2 proportional to .

32 is a function generator which receives signals S1 and S2 and outputs a high or low level voltage signal S5. In this embodiment, the signal s2 of the fuel injection amount Q and the engine rotational speed signal S
1 are respectively predetermined voltage values VQ1. VQ2. vNl
, for vN2, “Ql<S2<VQ2 + VNI
32a to 32d are comparators, and 32e is an AND circuit. .

33 is the signal S1. Differential pressure signal IS from S2 to differential pressure sensor 9
This is a function generator that outputs Gi number S3 corresponding to 5.

This is a differential pressure Δpo corresponding to the particle collection limit of the trap 3, and a reference differential pressure signal S5 corresponding to the engine rotational speed N and the solvent injection iQ is output. 34 is a comparator which outputs a high level voltage signal SII when the detected differential pressure signal IS5 becomes larger than the reference differential pressure signal S5.
Output.

35 and 36 are temperature sensors It and 12 temperature signals Is, respectively.
, , is an amplifier that amplifies IS5, and the amplified signal s5
．． Output s6. 37 is a comparator that outputs a high level voltage signal S7 when the amplified signal s5 is less than a predetermined value vT1, and 38 is a comparator that outputs a high level voltage signal S7 when the amplified signal S6 exceeds a predetermined value VT2. This is a comparator that outputs a signal s8. Here vTl is trap 3
VT2 is a value corresponding to the temperature limit that prevents the trap 3 from burning out.

39 is an AND circuit. This circuit has a signal S5+Sll
Only when all +87 are at the no-y level, the voltage signal S9 at the no-y level is output. That is, fuel injection lQ times signal 2
is VTI < S 2 < VQ2 + engine rotational speed signal S1 is VNl < S t < VH2 υ, and the detected differential pressure ΔP of the pressure before and after the flap detects the clogging υ condition necessary for trap regeneration, and the trap upstream When the temperature T1 of is at the trap regeneration temperature, 89 becomes a no-repel. In other words, when the engine rotational speed and the exhaust temperature upstream of the trap are in a state suitable for trap regeneration, or when the differential pressure across the trap is in a state where it is necessary to regenerate the trap due to trap clogging, the high level signal S9 is activated. This outputs the following.

The reason for determining the engine speed and engine load regeneration range as described above is that, for example, if the burner operates in a high engine speed range, a large amount of fuel is required, which is uneconomical in terms of fuel consumption, and Since there are situations, such as when the engine is running, where the exhaust gas temperature is air-cooled and it is difficult to maintain the trap regeneration temperature, the engine operating conditions for trap regeneration are determined to be within the best range.

40 is a function generator which calculates the amount of fuel q to be supplied to the burner 5 by inputting the engine rotational speed N signal S1 and the fuel injection amount Q signal S2 of the fuel injection pump, and is proportional to the amount of fuel q supplied to the burner. A voltage signal 810 is output. 4 and 1 are triangular wave generating circuits that output a signal Sll. A comparator 42 outputs a constant-period pulse signal 812 whose duty is determined by comparing the level of the fuel ji' signal 810 supplied to the burner with the triangular wave signal 8110. The on-duty of the pulse signal 812 increases as the voltage level of the fuel supply amount signal StO to the burner increases, increasing the opening/closing ratio of the electromagnetic on-off valve 6 and increasing the amount of fuel supplied to the burner 5. .

43 is a triangular wave generation circuit, which generates a predetermined voltage level V.
By comparing it with S in a comparator 42, a pulse signal S15 having a constant pulse width and a constant period is output.

45 to 48 are analog switches, which become closed (conductive) when a high level signal is input. 49 is an inverter,
50 is a transistor constituting the operating switch of the electromagnetic on-off valve 6; 51 is a power transistor for the ignition coil 13; 52H is a secondary coil; 53 is a secondary coil; 0N-OFF pulse signal 08 from a comparator 44;
2 is applied to the power transistor 51, an ignition voltage is applied to the spark plug 5d via the primary coil 52 and the secondary coil 53. If the reproduced signal S9 of the trap 3 is at a low level, the switch 4
5.47 is open, and the signal S12+815 is not input to the base of transistor 50.51. At this time, the output 5111 of the inverter 49 becomes a high level voltage, and the switches 46 and 48 are closed, and the transistors 50 and 50.
The base of 51 is Earthlehertna, which is transistor 50.
．． No current flows from the collector of 51 to the emitter. That is, when the trap 3 is not in a state suitable for regeneration, the electromagnetic on-off valve 6 is shut off to stop the fuel supply to the burner, and the ignition operation from the ignition plug 5d is also stopped.

On the other hand, when the signal S9 becomes high level and the trap 3 and engine conditions become suitable for regeneration, the analog switch 45.47 closes and the analog switch 46.48
is opened and the signal 812r S15 is applied to the base terminal of the husband transistor 50.51, so the electromagnetic on-off valve 6 opens and closes to supply fuel to the burner 5, and at the same time the spark plug 5d operates to supply fuel. is ignited and burned, and the particulates collected by the trap 3 are re-burned. put it here,
The fuel lid is supplied to the burner 5 by opening and closing the electromagnetic on-off valve 6. The electromagnetic on-off valve 6 is duty-controlled by a pulse signal according to the engine rotation speed and the accelerator pedal position, that is, the engine load, and the fuel is supplied to the burner 5 according to the amount of fuel required by the burner. quantity can be supplied.

Therefore, the control device A that calculates the amount of fuel to be supplied to the exhaust heating burner based on the output signals of the engine load detection device and the engine rotational speed detection device includes an f-V converter 30, a function generator 31, 40, and a triangular wave generator. The trap regeneration timing control device, which detects the trap regeneration timing and controls the activation timing of the electromagnetic on-off valve and the exhaust heating burner ignition device, is surrounded by a two-dot chain line B. It can be seen that the device is configured by a switching device.

The electromagnetic on-off valve 6 is constructed as shown in FIG. 3, for example.

That is, in the figure, a bobbin 104 wound with a coil 103 is inserted into a main magnetic pole 102 formed by passing a fluid passage 101 through the center thereof, and a front end surface of the main magnetic pole 102 and a valve seat opposite to this front end surface are inserted. A spherical valve body 106 made of a magnetic material is housed between the body 105 and the valve body 105 . A case 1 that houses and integrates the main magnetic pole 102, the pobbin 104, and the valve seat body 105.
07 is provided with a side magnetic pole 108 that regulates the direction of movement of the valve body 106, and a nozzle hole 109 that is opened and closed by the valve body 106 is bored in the center of the valve seat body 105. The upstream end (right end in the figure) of the passage 101 is connected to the discharge port of a fuel pump (not shown) via piping and regulator pulp (not shown), and the coil 103 is connected to the outlet port of a fuel pump (not shown) via a connector 110. It is connected to a controller (not shown). 111.112
.

113 is an O-ring, and 114 and 115 are shims.

In such a flow control solenoid valve, when a current is applied to the coil 103 to magnetize the main magnetic pole 102 and the side magnetic poles 10B, the electromagnetic force causes the valve element IQ6 to levitate from above the valve seat body 105, and the main magnetic pole 102 It is adsorbed to the tip surface of. Then, the fluid in the fluid passage 101 flows out to the outer periphery of the tip of the main magnetic pole 102 through the bypass passage 116 and flows out from the nozzle hole 109 formed in the valve seat body 105. Further, when the power supply to the coil 103 is cut off, the main magnetic pole 102 and the side magnetic poles 108 are demagnetized, and as a result, the valve body 106 is pushed to the left in the figure by the pressure of the fluid and is seated on the valve seat body 105.

Note that after the valve body 106 is seated on the valve seat body 105, the pressure of the fluid continues to press the valve body 106, so that the nozzle hole 1
09 remains closed. And again coil 10
3 is energized, the valve body 106 is attracted to the tip surface of the main magnetic pole 102 against the pressing force of the fluid, and the nozzle hole 109
to open.

As described above, this type of flow control electromagnetic on-off valve 6 controls the flow rate of the fluid flowing out (spouted) from the nozzle hole by changing the ON-OFF time of the coil, and has high flow rate control accuracy. be.

As described above, according to the present invention, the fuel flow rate injected from the burner is supplied with high precision according to the engine load and engine rotation speed, so the trap regeneration timing is detected and the above control is performed only at the necessary timing. It is possible to properly supply fuel and operate the spark plug, raise the exhaust temperature to the trap regeneration temperature with the minimum necessary amount of fuel, minimize deterioration in fuel efficiency, and perform oversupply of fuel. This can prevent burnout of the trap.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an embodiment of the exhaust particulate treatment device according to the present invention, Fig. 2 is a circuit diagram showing an embodiment of the control device described above, and Fig. 3 is a specific example of the electromagnetic shut-off valve described above. FIG. 4 is a graph showing the change in exhaust temperature with respect to the amount of fuel supplied to the burner using the parameter of engine rotation speed. A... Control device B... Trap regeneration timing control device 3... Trap 5... Burner 5d.
...Spark plug 6...Solenoid on-off valve 7...Fuel passage 9...Differential pressure sensor 11, 12...Temperature sensor 13...Ignition coil 2o...Control device 21...Engine rotation Speed detection device 22...
Accelerator position sensor 31, 40...Function generator
32゜33...Function generator 42...Comparator
45-48... Analog Switch Patent Applicant Nissan Motor Co., Ltd. Agent Patent Attorney Fujio Sasashima No. 3 Figure 110

Claims (1)

[Claims] An exhaust particulate treatment device for an internal combustion engine, comprising a trap that filters and collects particulates contained in the exhaust gas, and a burner for heating the exhaust gas provided upstream of the trap, the device comprising an engine load detection device and an engine rotation speed. a detection device, a control device that calculates and controls the amount of fuel to be supplied to the exhaust heating burner based on the output signals of these rain detection devices, and a fuel that is supplied to the exhaust heating burner in response to the output pulse signal of the skeleton control device. An internal combustion engine comprising an electromagnetic on-off valve that controls the flow rate, and a trap regeneration timing control device that detects the trap regeneration timing and controls the activation timing of the electromagnetic on-off valve and the igniter of the exhaust heating burner. Engine exhaust particulate processing equipment.