JPH1113455A - Diesel particulate filter device equipped with clogging detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diesel particulate filter device equipped with a clogging detector which reduces the extent of fuel consumption to carry out a filter regeneration properly according to a depositional quantity by detecting an amount of generation of particulates in conformity to an engine driving state in a highly accurate manner. SOLUTION: A controller 10 permeasures each clogging state of two filters 18 and 20 due to particulates by each detection signal from sensors 14, 15, 16 and 23 detecting an engine having state to be varied according to the elapse and an amount of generation of these particulates per unit time determined by measurement in advance is integrated, and thus this clogging state is judged by what a collective quantity of particulates integrated is reached to the specified value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel particulate equipped with a clogging detection device having a self-regeneration function for collecting particulates in exhaust gas discharged from a diesel engine and heating and burning the particulates. It relates to a filter device.

[0002]

2. Description of the Related Art Generally, most of the particulates in exhaust gas discharged from a diesel engine are composed of a compound of carbon and hydrocarbon (HC).
Usually, it is several μm to several tens μm. By the way, when particulates collected by a diesel particulate filter device are heated to about 600 ° C. or more in the presence of oxygen, they react with oxygen and easily burn and can be incinerated. It is necessary, and the temperature of the exhaust gas itself is not sufficient as a heat source, and the particulates cannot be completely burned.

In a conventional diesel particulate filter device, a filter is provided in an exhaust passage to efficiently collect particulates in exhaust gas, and after a certain period of time, the particulates accumulate on the filter and the filter is removed. When clogging occurs, the heating means is activated to heat and incinerate the particulates collected in the filter to regenerate the filter. Generally, a diesel particulate filter device has a large filter area, and the particulates are deposited and collected on the front face of the filter and the like, and the deposited particulates are heated and incinerated. Is provided.

For example, in a diesel particulate filter device disclosed in Japanese Utility Model Laid-Open No. 1-144427, an exhaust gas passes through a filter body, and the filter body collects particulates such as carbon and HC in the exhaust gas. When particulates accumulate in the filter body and clog the filter, shut off the flow of exhaust gas to the filter body and switch to the flow of exhaust gas to another filter body. From the downstream side of the clogged filter body Air is blown in and the filter body is heated to burn and incinerate the clogged particulates.

Japanese Patent Application Laid-Open No. Hei 6-123216 discloses an apparatus for detecting abnormality of a diesel particulate filter. The abnormality detecting device includes: a rotation detecting means for measuring a rotational speed of the diesel engine; a pressure detecting means for measuring a pressure acting on the filter element; and an identification for identifying a state of the filter element based on the measured rotational speed and pressure. Circuit. The identification circuit includes a reference value circuit that calculates an expected value of the pressure based on the total operation time of the diesel engine integrated after the reset and the rotation speed at that time,
A comparison circuit for comparing the pressure at that time with the expected value and outputting an abnormality detection signal when the pressure is below the allowable range of the expected value.

Further, Japanese Patent Application Laid-Open No. 60-85214 discloses a filter regeneration device for an internal combustion engine. The filter regeneration device includes a filter provided in an exhaust pipe for collecting particulates in exhaust gas, a pressure sensor provided on an upstream side and a downstream side of the filter, and an electric sensor for separating an AC fluctuation component of an output of the pressure sensor. And an arithmetic circuit for calculating the ratio of the output of each electrical filter, and a regeneration mechanism for reproducing the filter, and operating the regeneration mechanism based on the output of the arithmetic circuit.

[0007]

However, in the case of a diesel particulate filter device, detecting the clogged state of the filter involves a problem in the detection accuracy of the state. If the time for judging whether the filter is clogged is too early, the number of times the heating means heats the filter unnecessarily increases, the energy consumption such as electric power for operating the heating means increases, and particulates accumulate too much. Even when not performed, the filter is heated, thereby reducing the durability of the filter. In particular, in a type in which the heating means provided in the diesel particulate filter device is not configured by a burner or external power, the power is supplied from an AC generator or a battery provided in the engine, which leads to deterioration in fuel efficiency of the engine. Will be. Also, if the detection time of the clogged state of the filter is too late, the accumulation of particulates in the filter is too large, and the exhaust pressure loss of the engine increases, resulting in deterioration of fuel efficiency. .

In general, in a moving body such as a vehicle, electric energy is supplied from a battery. Electric power is supplied from a battery to a heater such as an electric wire mesh to heat particulates collected in a filter. Will run out of electrical energy. Therefore, as a diesel particulate filter device, it is possible to properly control the heating and incineration timing of particulates, appropriately reduce the period during which power is supplied to the heating means, and minimize the power supplied to the heating means. It is conceivable that consumption can be reduced and fuel consumption can be reduced. Further, Japanese Patent Application Laid-Open No.
In the diesel particulate filter device disclosed in Japanese Patent No. 23216 or Japanese Patent Application Laid-Open No. 60-85214, the detection of the clogged state of the filter detects the engine speed and the load every moment as the vehicle travels. The clogged state of the filter provided in the passage changes the exhaust gas flow rate due to the heat capacity of the exhaust pipe and the like, and the pressure acting on the filter element fluctuates. Cannot do it.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problem. In collecting particulates in exhaust gas by a filter, the clogged state of the filter is changed to the operating state of the engine, that is, the operation of the engine. In response to the condition, the controller integrates and detects the clogging time, activates the heating means in response to the amount of generated particulates, that is, the predetermined amount of accumulated particulates on the filter, heats and incinerates the particulates, and uses the heating means. An object of the present invention is to provide a diesel particulate filter device provided with a clogging detection device capable of reducing power consumption and improving fuel efficiency.

[0010] The present invention provides an exhaust gas passage communicating with an exhaust pipe of a diesel engine, a heat-resistant filter disposed in the exhaust gas passage, heating means for heating and incinerating particulates disposed in the filter, and A controller for controlling the heating and incineration of the particulates by operating the heating means in response to a clogged state of the filter by the particulates collected by the filter, wherein the controller is configured to control the particulate by the particulates; Accumulates the amount of particulate generation based on the amount of particulate generation per unit time, which is measured and determined in advance, based on a detection signal from a sensor that detects the engine operating state that changes over time as the filter clogs. And the integrated amount of the generated particulates reaches a predetermined value. It is determined by the related diesel particulate filter device provided with a clogging detection device according to claim.

Further, the sensor for detecting the engine operating state is constituted by a sensor for detecting an engine rotation speed and a fuel flow rate.

Further, the sensor for detecting the engine operating state comprises an intake pressure sensor for detecting an intake pressure and a temperature sensor for detecting an intake temperature. The correction is made in response to the intake pressure and the intake temperature detected by the atmospheric pressure sensor and the temperature sensor.

[0013] The diesel particulate filter device according to the present invention is configured as described above.
The amount of particulates emitted from the diesel engine itself is calculated for each unit time by the controller by detecting the intake pressure, intake temperature, engine speed, and fuel injection amount, and the amount of particulates generated sequentially is integrated. The filter clogging time is determined, and when the amount of particulates deposited on the filter reaches a predetermined value, the heating means is operated to heat and burn the particulates, thereby regenerating the filter.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a diesel particulate filter device provided with a clogging detection device according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic system diagram showing an embodiment of a diesel engine incorporating a diesel particulate filter device provided with a clogging detection device according to the present invention, and FIG. 2 is a diagram for measuring a particulate generation amount under engine operating conditions. 4 is a graph showing a relationship between a rotation speed of a diesel engine and a fuel flow rate.

The diesel engine 1 incorporating the diesel particulate filter device is, for example, a multi-cylinder engine. Air taken in through an air filter 13, that is, intake air, flows from an intake passage 12 to a combustion chamber of each cylinder through an intake manifold 11. The fuel is supplied to each combustion chamber, and fuel is injected from the fuel injection nozzle 17 through the fuel supply passage 22 by the operation of the fuel injection pump 9.
Exhaust gas generated in each combustion chamber is collected in an exhaust manifold 2, and the collected exhaust gas is discharged through an exhaust gas passage 3.

The exhaust gas passage 3 is branched in the middle into a pair of exhaust gas passages 4 and 5. The branch portion is provided with a switching valve 8 that can be switched by a command from the controller 10 so that the exhaust gas from the exhaust gas passage 3 flows into one of the exhaust gas passages 4 and 5. In each exhaust gas passage 4, 5, a diesel particulate filter 6,
7 are arranged respectively. The diesel particulate filters 6 and 7 include heat-resistant filters 18 and 20 disposed in casings respectively incorporated in the exhaust gas passages 4 and 5 for purifying exhaust gas, and a heater 19 constituting heating means. , 21 are provided. The purified exhaust gas that has passed through the diesel particulate filters 6 and 7 is discharged from the exhaust gas passages 4 and 5 and is collected in the exhaust gas passage 3 and discharged to the outside such as the atmosphere.

This diesel particulate filter device has an intake air temperature sensor 16 provided in the intake passage 12 for detecting the temperature T of the intake air, and an intake pressure sensor 15 provided in the intake passage 12 for detecting the intake pressure P. doing.
Further, the diesel particulate filter device includes an engine rotation sensor 14 for detecting a rotation speed R of the engine 1 and a fuel injection nozzle
A fuel flow rate sensor 23 for detecting a fuel injection amount, that is, a fuel flow rate F, which is injected into the combustion chamber through the fuel cell 7. The fuel flow sensor 23 is provided in the fuel injection pump 9 and can directly measure and detect the fuel flow F supplied from the fuel injection pump 9.

In this diesel particulate filter device, the controller 10 switches the switching valve 8 so that the exhaust gas flows through either the diesel particulate filter 6 or 7. Controller 10
Calculates the amount of particulates accumulated on the filter 18 or 20 through which the exhaust gas flows, that is, the amount of particulates generated in response to the operating condition of the engine. When the amount of particulates accumulated on the filter 18 or 20 reaches a predetermined amount, , The switching valve 8 is switched, the exhaust gas is caused to flow to the other filter 18 or 20, and the filter 1 on which the particulates are deposited is used.
Control is performed to energize the heaters 19 or 21 of 8 or 20 and heat and incinerate the particulates deposited on the filter 18 or 20.

In this diesel particulate filter device, the clogging state of the filters 18 and 20 due to the particulates collected by the filters 18 and 20 can be detected as follows. Controller 10
Indicates the amount of particulate generation determined in advance by measuring the clogged state of the filters 18 and 20 due to particulates, in particular, by the detection signals from the sensors 14, 15, 16 and 23 for detecting the engine operating state. Accumulation is performed, and it is determined that the accumulated amount of the accumulated particulates reaches a predetermined value. The diesel particulate filter device is configured to detect an engine rotation speed R, a fuel injection amount F into a combustion chamber, an intake pressure P, and an intake temperature T as an engine operation state.

Generally, the amount X of particulates in the exhaust gas discharged from the diesel engine 1 is represented by an intake pressure P, an intake temperature T, an engine rotation speed R, and a fuel flow rate F.
And the fuel injection timing.
Diesel engine commercially available is measured these relationships are already particularly, NO _X, CO, so the amount of generation of such smoke is minimized, the fuel injection timing is set. Therefore, if the engine rotation speed R and the fuel flow rate F change, those values are input to the controller 10 and calculated, whereby the amount X of the generated particulates is calculated. Normally, in an engine bench test, particulates are measured with the intake air in a standard state (atmospheric pressure: 760 mmHg, temperature: 20 ° C., humidity: 65%). Even when the intake air is in the standard state, when passing through the air cleaner, the intake pressure and the intake temperature do not become the same values as those in the standard state but different values due to resistance and heat received from the intake pipe. Therefore, in the following description, when the intake pressure measured when the atmospheric state is the standard state is P and the intake temperature is T, the intake pressure when the atmospheric state is not the standard state is P ₁ , the intake temperature It will be described as distinguished as T _1.

That is, in the diesel engine 1, the amount X of particulates contained in the exhaust gas discharged from the combustion chamber is defined as a unit when the atmospheric condition is a standard condition (intake pressure P, intake temperature T). Assuming the amount generated per hour, the value is measured in advance based on the engine rotation speed R and the engine load, that is, the fuel flow rate F. As shown in FIG. 2, when the engine speed R is plotted on the horizontal axis and the fuel flow rate F is plotted on the vertical axis, the measurement points become infinite.
Several meshes per unit, for example, the engine speed R is set to 10 sections (A, B, C, D, E, F, G, H, I
And J), and the fuel flow rate F is divided into 10 sections (a, b,
c, d, e, f, g, h, i and j). The meshes (Aa, A) at the engine rotation speed R and the fuel flow rate F when the atmospheric state is the standard state (intake pressure P, intake temperature T)
b, ──Fe, Ff, ──, Ji, Jj) represent the amount of particulates generated per unit time in a value (XAa, XAb, ──XFe, XFf, ──,
XJi, XJj) are measured in advance by a bench test. The controller 10 controls the engine speed R and the fuel flow rate F in the operating state of the engine per unit time.
(Aa, Ab, ──Fe, Ff,
(XAa, XAb, {XFe, XFf,}, XJ)
i, XJj) is stored, the integrated value is calculated by integrating the values during the engine operation period, and the value is stored in the memory of the controller 10 as the total generation amount of particulatesΣX. The controller 10 can output the total amount of particulates ΔX generated under certain engine operating conditions.

Further, in the diesel engine 1, the true amount of particulates generated per unit time Y depends on the intake pressure P as other operating conditions of the engine speed R and the fuel flow rate F.
₁ and the intake temperature T ₁ , the true amount of particulates generated per unit time Y is corrected by the intake pressure P ₁ and the intake temperature T ₁ . That is, the amount of generated particulates is closely related to the flow rate of oxygen contributing to combustion. For example, the high intake air temperature T _1, the density of the intake That air is lowered, resulting in the amount of oxygen is reduced, therefore the amount of smoke produced i.e. particulates increases. Further, the high intake air pressure P _1, air i.e. the density of the air is increased, the amount of oxygen is increased, the true generation amount Y of smoke i.e. particulates become active combustion is reduced. When the operating conditions of the intake air temperature T and the intake air pressure P are changed,
For a given engine, measure the increase or decrease in the amount of particulates generated in a bench test,
Increase or decrease of the measured amount of generated particulates
The coefficient of the particulate generation amount X when the atmospheric state is the standard state (intake pressure P, intake temperature T), that is, the intake temperature correction coefficient k _IT and the intake pressure correction coefficient k _IP are obtained in advance. If these coefficients k _IT and k _IP are stored in the memory of the controller 10 and are set so that they are multiplied when the controller 10 calculates the particulate generation amount X, the true generation of particulates per unit time is possible. The quantity Y can be measured with high accuracy.

In this diesel particulate filter device, as described above, the controller 10 calculates the amount X of particulates generated per unit time when the atmospheric state is in the standard state (intake pressure P, intake temperature T). Therefore, the clogging state of the filters 18 and 20 due to the particulates is corrected in response to the intake pressure P ₁ detected by the intake pressure sensor 15 and the intake temperature T ₁ detected by the intake temperature sensor 16. can do. That is, the diesel particulate filter device, the amount of particulates per unit time when the intake pressure P ₁ and the intake temperature T ₁ of the by atmospheric conditions are standard conditions (intake pressure P, intake air temperature T) By correcting X, the clogged state of the filters 18 and 20 can be detected with high accuracy. In the diesel engine 1, according to the intake air pressure P ₁ is not less different generation amount Y of particulates per true unit time, the intake pressure correction coefficient k _IP. Further, the intake air temperature T generation amount Y of particulates per true unit time depending on are different, when the intake air temperature correction coefficient k _IT, particulate emission per true unit time Y (mmg) Is as follows: That is, Y = X × k _IP × k _IT .

As described above, the controller 10 measures the engine rotational speed R and the engine load, that is, the fuel flow rate F, to determine that the atmospheric state is in the standard state (the intake pressure P,
The particulate generation amount X (mmg) per unit time in the engine operating state at the intake air temperature T) can be calculated, and the intake pressure P ₁ and the intake air temperature T ₁ are added to these values.
Is multiplied by an intake temperature correction coefficient k _IT and an intake pressure correction coefficient k _IP , which have been obtained in advance, to accurately correct the particulate generation amount Y per unit time. Controller 10
Accumulates them as time passes, so that the generated amount ΣY obtained by integrating the true particulate generation amount Y per unit time reaches a predetermined amount of particulates that causes the filters 18 and 20 to be clogged. The time is calculated, and control is performed to determine that the time is the clogged state of the filters 18 and 20. As described above, the controller 10
Based on the engine rotation speed R from the engine rotation sensor 14 and the fuel flow rate F from the fuel flow rate sensor 23, it is possible to calculate the generation amount ΣY of the particulates discharged from the engine 1 with high accuracy.

[0025]

Since the diesel particulate filter device having the clogging detection device according to the present invention is constructed as described above, when used in a moving body such as a vehicle, the particulate matter is heated and incinerated. When power is supplied to the heating means to be heated, it is supplied from a generator driven by a diesel engine or a battery mounted on the vehicle. The period is appropriately reduced, the power supplied to the heating means can be minimized, power consumption can be reduced, and deterioration of fuel efficiency of the engine can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic system diagram showing an embodiment of a diesel engine incorporating a diesel particulate filter device provided with a clogging detection device according to the present invention.

FIG. 2 is a graph showing a relationship between a rotational speed of a diesel engine and a fuel flow rate for measuring a particulate generation amount under engine operating conditions.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Diesel engine 2 Exhaust manifold 3,4,5 Exhaust gas passage 6,7 Diesel particulate filter 8 Switching valve 9 Fuel injection pump 10 Controller 11 Intake manifold 12 Intake passage 13 Air filter 14 Engine rotation sensor 15 Intake pressure sensor 16 Intake temperature Sensor 17 Fuel injection nozzle 18, 20 Filter 19, 21 Heater 22 Fuel passage 23 Fuel flow sensor

Claims (3)

[Claims] 1. An exhaust gas passage communicating with an exhaust pipe of a diesel engine, a heat-resistant filter disposed in the exhaust gas passage, heating means for heating and burning particulates disposed with respect to the filter, and the filter. A controller for controlling the heating and incineration of the particulates by operating the heating means in response to the clogged state of the filter due to the particulates collected in the filter, wherein the controller is configured to control the filter by the particulates. The clogging state is integrated with the amount of particulates generated based on the amount of particulates generated per unit time, which is measured and determined in advance, based on a detection signal from a sensor that detects an engine operating state that changes with time. That the integrated amount of particulates reaches a predetermined value. A diesel particulate filter device provided with a clogging detection device characterized in that the determination is performed. 2. The diesel engine according to claim 1, wherein the sensor for detecting the engine operating state comprises a sensor for detecting an engine rotation speed and a fuel flow rate. Particulate filter device. 3. The sensor for detecting the operating state of the engine includes an intake pressure sensor for detecting an intake pressure and a temperature sensor for detecting an intake air temperature, and the clogging state of the filter due to the particulates is the intake pressure. The diesel particulate filter device according to claim 2, wherein the correction is made in response to an intake pressure and an intake temperature detected by a sensor and the temperature sensor.