JP2005320862A - Exhaust gas reducing device for diesel engine and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas reducing device for a diesel engine provided with warning devices for warning a driver to take a proper safety measure, when a filter is not normally operated, by easily adjusting a reference value for controlling the filter so as to operate at the proper temperature for burning and removing a collected particulate toxic substance. <P>SOLUTION: This exhaust gas reducing device has: an exhaust pipe 10 provided with the filter 11 for removing dust of exhaust gas and connected to an exhaust manifold 2 of the engine 1; a pressure sensor part 20 arranged in a front end part of the filter of the exhaust pipe 10 and sensing pressure; a temperature sensor part 30 arranged in a rear end part of the filter of the exhaust pipe 10 and sensing the temperature; an input device 41 for writing in reference value data; a memory part 42 for storing the data, a control part 43 for performing a comparison and arithmetic processing of the data; the warning devices 44 and 45 controlled by the control part 43; and a power terminal part 46 connectable with a battery. The device also has a control device 40 connected to the pressure sensor part 20 and the temperature sensor part 30. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exhaust gas reduction device for a diesel engine and a control method thereof, and more particularly, to an exhaust gas reduction device for a diesel engine provided with a filter provided in the exhaust gas reduction device and removing particulate matter of the exhaust gas, and control thereof. Regarding the method.

  Generally, in a diesel engine, fuel is combusted in the cylinder of the engine, and the exhaust gas is discharged to the outside through an exhaust manifold, an exhaust pipe, and a silencer.

  The exhaust gas that is burned and discharged by the engine in this way includes carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NOx), carbon particles, etc., which are discharged into the atmosphere, Causes serious air pollution.

  In order to prevent such air pollution, regulations on acceptable standards for environmental pollutants are being strengthened to further reduce the exhaust gas of vehicles, and such legal regulations also cause emissions from vehicles in the automobile industry. Technologies for reducing harmful gases and producing environmentally friendly vehicles have been proposed.

  In the exhaust gas reduction device for this purpose, as a device for removing particulate matter (particulate matter) combusted by the engine and discharged from the exhaust pipe, for example, the particulate matter is captured using a metal net, ceramic foam, or the like. There are a filtration system that collects and a regeneration system that burns and removes the particulate matter collected by the filter.

  As an exhaust gas reduction device for regeneration, catalytic conversion is provided with a catalytic filter that converts harmful gases such as carbon monoxide, hydrocarbons, and nitrogen oxides discharged from the exhaust pipe into harmless substances through oxidation-reduction reactions. An apparatus is disclosed.

  In addition, a technique is disclosed in which carbon-containing particles contained in exhaust gas discharged from an internal combustion engine are collected by a thermal resistance filter and burned by the filter (see Patent Document 1).

  The regeneration method that burns and removes the particulate matter collected in the filter in this way cannot remove harmful substances efficiently unless the filter is kept at an appropriate temperature, and the appropriate temperature is maintained. If not, the filter may be clogged with particulate matter and not function properly.

  Therefore, the regenerative exhaust gas reduction device is provided with various sensors for detecting the conditions under which the filter functions normally, and the signal of this sensor is transmitted to the control device and compared with the reference value that has already been set. To be kept in proper conditions.

  In Patent Document 1, a pressure sensor and a temperature sensor are provided at the front end portion and the rear end portion of a thermal resistance filter capable of temperature control, respectively, and a pressure difference and a temperature difference between the thermal resistance filters are sensed. By comparing the temperature difference with the set value that has already been set, the temperature of the thermal resistance filter is controlled so that smooth operation is performed.

  Therefore, in such an exhaust gas reduction device of the regeneration system, a reference value is stored in the electronic control unit in order to determine the conditions under which the filter functions normally, and the electronic control unit is already set with the measured signal. Compared reference values are used to control the filter to operate under appropriate conditions or to activate a warning device.

  However, after the exhaust gas reduction device is produced, it is necessary to adjust the appropriate operating conditions of the filter in the field according to the vehicle type and displacement, but the conventional exhaust gas reduction device has a standard value determined at a fixed value. Since it is stored in the electronic control unit, there is a problem that it is difficult to adjust the reference value.

European Patent Application Publication No. 1270884

  The present invention has been made in view of the above problems, and it is easy to adjust a reference value for controlling a filter that burns and removes collected particulate harmful substances to operate at an appropriate temperature. An object of the present invention is to provide an exhaust gas reduction device for a diesel engine.

  Another object of the present invention is to provide an exhaust gas reduction device for a diesel engine provided with a warning device that informs the driver of taking appropriate safety measures when the filter is not in a normal operating condition. To do.

  In order to achieve the above object, in the exhaust gas reduction device for a diesel engine according to the present invention, an exhaust pipe provided with a filter for removing particulate matter in the exhaust gas and connected to the exhaust manifold of the engine, and the exhaust pipe A pressure sensor for sensing pressure, a temperature sensor for sensing temperature, and a temperature sensor for sensing temperature, an input device for writing reference value data, and data A memory unit for storing, a control unit for comparing and calculating data, a warning device controlled by the control unit, and a power supply terminal unit connectable to a battery, and connected to the pressure sensor unit and the temperature sensor unit And a control device.

  Further, in the control method of the exhaust gas reduction device for a diesel engine according to the present invention, in the control method of the exhaust gas reduction device provided with the filter for reducing particulate matter of the diesel engine, the ignition of the engine is started after the ignition of the engine starts. A first step of sensing the pressure at the front end and the temperature at the rear end of the filter, comparing the sensed pressure with a preset pressure reference value and alerting if the sensed pressure is greater than the pressure reference value A second step of operating the device, and a third step of comparing the sensed temperature to a preset maximum temperature reference value and activating the warning device if the sensed temperature is greater than the maximum temperature reference value; It is characterized by including.

  In addition, an exhaust pipe provided with a filter for removing particulate matter of exhaust gas discharged from the exhaust manifold in the present invention, a sensor unit provided in the exhaust pipe for sensing exhaust pressure, and a signal of the sensor unit And setting a reference value in the ignition state of the engine in a method for setting a pressure reference value for controlling an exhaust gas reduction device for a diesel engine comprising a control device storing a reference value for control And a first step in which the exhaust pressure acting on the front end of the filter is measured by the exhaust manifold while the engine is driven at an engine speed greater than or equal to a predetermined value for a fixed time. And a third step of calculating a pressure reference value and storing the calculated exhaust pressure.

  Since the exhaust gas reduction device of the present invention includes an input device for writing reference value data, the reference value can be appropriately adjusted according to the appropriate operating conditions of the filter.

  Since the control method of the present invention has a second step and a third step of operating the warning device when the sensed temperature and pressure are compared with the temperature reference value and the pressure reference value, respectively, and greater than the reference value, The operating status of the exhaust gas reduction device can be constantly monitored to take action for malfunctions at an early stage.

  According to the pressure reference value setting method of the present invention, an exhaust pressure at an engine speed greater than a predetermined value, for example, a maximum engine speed and a minimum drive engine speed, is measured, and a pressure reference value is calculated based on the measured value. Therefore, the pressure reference value according to the specification and performance of each engine mounted on the vehicle can be obtained.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIGS. 1 to 3 are diagrams showing an exhaust gas reduction device for a diesel engine according to the present invention. FIG. 1 is a configuration diagram thereof, and FIG. 2 is a preferred embodiment of a logic circuit configuration of the control device. FIG. 3 is a plan view showing a specific example of the appearance of the control device.

  The exhaust gas reduction device for a diesel engine according to the present invention is provided with a filter 11 for removing exhaust gas dust, and is connected to an exhaust manifold 2 of the engine 1 and a front end portion of the filter of the exhaust pipe 10. A pressure sensor unit 20 for sensing pressure; a temperature sensor unit 30 for sensing temperature; an input device 41 for writing reference value data; and data stored in the rear end of the filter of the exhaust pipe 10. A memory unit 42, a control unit 43 for comparing and calculating data, warning devices 44 and 45 controlled by the control unit 43, and a power supply terminal unit 46 (see FIG. 3) connectable to a battery, A technical feature is that the pressure sensor unit 20 and the control device 40 connected to the temperature sensor unit 30 are provided.

  A filter 11 is provided inside the exhaust pipe 10, and the filter 11 burns and removes the particulate matter collected within a range of an appropriate temperature.

  The pressure sensor unit 20 is fixed to the front end portion of the filter of the exhaust pipe 10 and detects the pressure of the exhaust gas discharged from the exhaust manifold 2.

  It is preferable that the temperature sensor unit 30 is fixed to the rear end portion of the filter of the exhaust pipe 10 and is located adjacent to the filter within a possible range to measure the temperature of the filter.

  The control device 40 processes signals sensed by the pressure sensor unit 20 and the temperature sensor unit 30 and, when the filter 11 is out of proper operating conditions, alerts the driver to take appropriate measures. Is activated.

  The control device 40 includes an input device 41 capable of setting filter operating conditions, a memory unit 42 for storing data, and a control unit 43 for comparing and calculating data input from the sensor unit and a set reference value. And a buzzer 44 and a warning lamp 45 that are operated by the control of the control unit 43, and a power supply terminal unit 46 for supplying power.

  The input device 41 is for writing data from the outside and may be a dip switch or a keypad for generating an electrical signal by key input and inputting data.

  Hereinafter, a preferred embodiment of the logic circuit of the control device will be specifically described with reference to FIG.

  The pressure sensor unit 20 and the temperature sensor unit 30 are respectively connected to a comparator 433 via a signal converter 432, and measured values of pressure and temperature detected by the pressure sensor unit 20 and the temperature sensor unit 30 are compared with the comparator 433. Is input.

  The DIP switch 411 for setting the temperature reference value and the DIP switches 412 and 413 for setting the first and second pressure reference values are connected to the comparator 433 by the D / A converter 431, respectively. The reference values set at 412, 413 are used as reference values for comparison judgment by the comparator 433.

  The comparator 433 compares the reference value set by the DIP switches 411, 412, and 413 with the input temperature or pressure measurement value, and outputs an appropriate signal depending on whether or not the reference value is greater than or equal to the reference value.

  The signal compared and determined by the comparator 433 is transmitted to the processing unit 434, and the processing unit 434 turns on / off the buzzer 44 or the warning lamp 45 according to the input signal.

  FIG. 3 is a plan view showing a specific example of the appearance of the control device, and the case 400 is provided with a plurality of warning lights 45, each warning light 45 being equal to or higher than a reference temperature at which a filter is set, or When the pressure reference value is larger than the pressure reference value of 1 or the second pressure reference value, the state is notified.

  Inside the case 400, a buzzer (not shown) and a dip switch 411 capable of adjusting a reference value are provided.

  The control device 40 is provided with a power supply terminal portion 46 that can be connected to a battery or a sensor with a cable, and a reset switch 47 that is connected to a warning light 45 and releases the lighting state when the warning light 45 is operated. ing.

  The warning light 45 is preferably configured to be extinguished only by the reset switch 47 independently of the vehicle start key, in a state where the driver does not recognize the lighting state of the warning light 45. This is to prevent the warning light 45 from turning off when the start key is turned off. Therefore, after the driver recognizes that the warning lamp 45 is in the lighting state, the driver operates the reset switch 47 to turn off the warning lamp 45.

  The control device configured as described above is attached at a position close to the driver's seat so that the warning signal can be recognized when the warning light or the buzzer is activated.

  Hereinafter, a control method of the exhaust gas reduction device for a diesel engine according to the present invention configured as described above will be described.

  4 and 5 are diagrams showing a control method of an exhaust gas reduction device for a diesel engine according to the present invention. FIG. 4 is a flowchart showing the flow of the overall control, and FIG. 5 is a pressure reference value thereof. It is a flowchart which shows the process of setting.

  Referring to FIG. 4, in the first step (S10), pressure P and temperature T of exhaust gas exhausted from the exhaust manifold after engine start are measured.

  At this time, a pressure sensor unit is provided at the front end of the filter and measures a pressure value acting on the filter. The temperature sensor unit is provided at the rear end of the filter and measures the actual temperature of the filter adjacent to the filter within a possible range.

  In the second step (S20), the measured pressure is compared with the pressure reference value, and if the measured pressure is larger than the set pressure, the warning device is activated.

  When the pressure of the exhaust gas measured in the first step (S10) is equal to or higher than a certain pressure, the temperature of the filter increases due to the high pressure, which may cause filter damage. Therefore, if the pressure is above a certain level, the warning device is activated so that the driver takes appropriate safety measures.

  The pressure reference value includes a first pressure reference value PL and a second pressure reference value PH. When the detected pressure is larger than the first pressure reference value or the second pressure reference value, a warning device It is preferable to operate.

  At this time, the first pressure reference value PL is set at a pressure lower than the second pressure reference value PH, and if the detected pressure is larger than the first pressure reference value, an abnormal pressure is generated in the filter. Since there is a fear, the warning device issues a primary warning requesting the driver's attention.

  Then, if the sensed pressure is greater than the second pressure reference value, the filter is damaged, and the driver is informed that urgent action is necessary.

  The first pressure reference value and the second pressure reference value are experimentally determined within a range in which the set pressure reference value does not damage the filter. A method for determining the reference value will be described later.

  Here, in the second step (S20), the sensed pressure P is compared with the second pressure reference value PH (S21), and the sensed pressure P is compared with the first pressure reference value PL. Step (S22), and when the detected pressure is larger than the first pressure reference value PL or the second pressure reference value PH, turning on the buzzer and the warning light and operating the warning device (S23) It is made up of.

  The buzzer is turned off after being actuated by a timer for a certain time (S24).

  In the third step (S30), the measured temperature T is compared with the preset maximum temperature reference value TH, and if the measured temperature is greater than the reference value, the warning device is activated.

  If the measured temperature is equal to or higher than the temperature at which the filter operates normally, it may cause damage to the filter. Set as.

  At this time, the maximum temperature reference value TH varies depending on the filter, but is preferably determined at about 600 ° C.

  Here, the third step (S30) includes a step (S31) of comparing the sensed temperature T with the maximum temperature reference value TH. If the sensed temperature T is greater than the maximum temperature reference value TH, a buzzer and And a step (S32) of turning on the warning lamp and operating the warning device.

  At this time, the buzzer is turned off after being actuated by a timer for a predetermined time (S33).

  In the fourth step (S40), the warning light is turned off only by the reset switch while the warning light is on. Here, in the fourth step (S40), whether or not the reset switch is on after the warning lamp is turned on according to the conditions in the second step (S20) and the third step (S30). Is determined (S41), and when the reset switch is on, the warning light is turned off (S42).

  Therefore, if the driver does not turn off the warning light by operating the reset switch while the warning light is on, the warning light will remain on even if the engine is started after the start key is turned off. By maintaining, it informs the driver that the filter does not perform its normal function.

  In the fifth step (S50), it is determined whether or not the start key is in an off state. When the start key is maintained in an on state, the process returns to the first step (S10).

  Hereinafter, a method for setting a pressure reference value in the exhaust gas reduction device for a diesel engine according to the present invention will be described with reference to FIG.

  First, in the first step (S60), a reference value setting mode is performed using the input device of the control device in the engine start state.

  Next, in a second step (S70), the exhaust pressure acting on the filter front end is measured by the exhaust manifold. At this time, the driver operates the accelerator pedal so that the maximum engine speed (rpm) is maintained for a certain period of time to idle the engine (S71).

  The engine idling time and the minimum engine driving speed are the extraction conditions for exhaust pressure data necessary to calculate a reliable pressure reference value. It can be determined experimentally or empirically depending on the vehicle type or displacement.

  Next, in the third step (S80), a pressure reference value is calculated using the exhaust pressure measured in the second step (S70) and stored in the memory unit.

  Here, the average value of the exhaust pressure for a certain period of time is calculated from the maximum engine speed (rpm), and the average value of the exhaust pressure at the maximum engine speed calculated is multiplied by a certain proportionality constant. Preferably, a pressure reference value of 1 and a second pressure reference value are determined.

  That is, the critical pressure at which the filter is damaged is set as the second pressure reference value, and a pressure condition that is smaller than the second pressure reference value but may cause filter damage is set as the first pressure reference value.

  Further, the proportional constants corresponding to the first pressure reference value and the second pressure reference value may be determined experimentally and empirically according to the vehicle type and the displacement, and according to the vehicle type and the engine displacement. It may be determined uniquely.

  As described above, according to the present invention, it is possible to easily adjust the reference value by setting the reference value that allows the filter of the exhaust gas reduction device to operate at an appropriate temperature and storing the data.

  Moreover, when the filter of the exhaust gas reduction device is not in a normal operating condition, it is possible to prevent the exhaust gas reduction device from being damaged due to a malfunction by notifying the driver that appropriate safety measures are taken.

It is a block diagram of the exhaust gas reduction apparatus for diesel engines by this invention. It is a figure which shows the logic circuit structure of the control apparatus in the exhaust gas reduction apparatus for diesel engines by this invention. It is a figure which shows a specific example of the external appearance of the control apparatus in the exhaust gas reduction apparatus for diesel engines by this invention. It is a flowchart which shows the process of the whole control in the exhaust gas reduction apparatus for diesel engines by this invention. It is a flowchart which shows the process in which the pressure reference value in the exhaust gas reduction apparatus for diesel engines by this invention is set.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Exhaust pipe 11 Filter 20 Pressure sensor part 30 Temperature sensor part 40 Control apparatus 41 Input device 42 Memory part 43 Control part 44 Buzzer 45 Warning light

Claims (6)

An exhaust pipe provided with a filter for removing particulate matter in the exhaust gas and connected to the exhaust manifold of the engine;
A pressure sensor provided at the front end of the exhaust pipe filter for sensing pressure;
A temperature sensor unit provided at a rear end of the exhaust pipe filter for sensing temperature;
An input device for writing reference value data, a memory unit for storing data, a control unit for comparing and calculating data, a warning device controlled by the control unit, and a power supply terminal unit connectable to a battery, An exhaust gas reduction device for a diesel engine, comprising: a pressure sensor unit; and a control device coupled to the temperature sensor unit. The exhaust gas reduction device for a diesel engine according to claim 1, wherein the warning device includes a buzzer and a warning light, and the warning light further includes a reset button for releasing the lighting state. In a control method of an exhaust gas reduction device provided with a filter for reducing particulate matter of a diesel engine,
A first step of sensing the pressure at the front end of the filter and the temperature at the rear end of the filter after the ignition of the engine begins;
A second step of comparing the sensed pressure with a preset pressure reference value and activating the warning device if the sensed pressure is greater than the pressure reference value;
And a third step of comparing a sensed temperature with a preset maximum temperature reference value and activating a warning device when the sensed temperature is greater than the maximum temperature reference value. Control method for exhaust gas reduction device. The pressure reference value in the second step is composed of a first pressure reference value and a second pressure reference value, and the sensed pressure is greater than the first pressure reference value or the second pressure reference value. A control method for the exhaust gas reduction device for a diesel engine according to claim 3, wherein a warning device is operated. The warning device in the second step or the third step is a warning light, and further includes a step of releasing the lighting by a reset button connected to the warning light after the warning light is turned on. The control method of the exhaust gas reduction apparatus for diesel engines of Claim 3 or Claim 4 to do. An exhaust pipe provided with a filter for removing particulate matter in the exhaust gas discharged from the exhaust manifold, a sensor part provided in the exhaust pipe for sensing exhaust pressure, and a signal from the sensor part being sensed and controlled A method for setting a pressure reference value for controlling an exhaust gas reduction device for a diesel engine having a control device storing a reference value for
A first step in which a mode for setting a reference value in an ignition state of the engine is performed;
A second step in which the exhaust pressure acting on the front end of the filter is measured by the exhaust manifold while the engine is driven at an engine speed greater than or equal to a predetermined value for a fixed time;
A third step of calculating a measured exhaust pressure and calculating and storing a pressure reference value.

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