KR102488199B1 - Diesel Particle Filter manual regeneration system and method - Google Patents

Abstract

A DPF forced recovery system and method for a work vehicle are disclosed. The DPF forced regeneration system of a work vehicle according to an embodiment of the present invention includes a manual regen switch for generating a regeneration conversion signal for switching to a regeneration mode, a hydraulic discharge port through which hydraulic oil discharged by a hydraulic pump is moved A hydraulic supply line for supplying hydraulic oil intermittently supplied from the hydraulic discharge line to the actuator, a variable valve for controlling the movement of hydraulic oil between the hydraulic discharge line and the hydraulic supply line, and a hydraulic pressure installed on the inlet side of the variable valve The regeneration control valve unit consisting of the pressure control valve on the bypass line connecting the discharge line and the hydraulic supply line installed on the outlet side of the variable valve and the regeneration switching signal generated by the forced regeneration switch control the variable valve so that the hydraulic oil is supplied to the bypass line. It is characterized in that it is configured to include an ECU that controls to pass through.

Description

DPF forced regeneration system and method of working vehicle {Diesel Particle Filter manual regeneration system and method}

The present invention relates to a system and method for compulsory DPF recovery of a working vehicle, and more particularly, an operation for restoring the performance of a diesel particle filter (DPF) installed in a diesel engine exhaust line for filtering fine pollutants. It relates to a system and method for compulsory DPF regeneration of a car.

As a diesel engine exhaust gas post-processing device for minimizing air pollutant generation and preserving the atmospheric environment, a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF) are used. Referred to as 'DPF') is widely adopted in the art.

Among them, the DPF is installed between the engine and the muffler and plays a role in removing fine-sized particulate matter (PM) among foreign substances included in the exhaust gas discharged from the diesel engine. This DPF is applied to all diesel engines, including engines used in various vehicles and facilities, from general passenger cars to industrial vehicles and ships.

1 is a cross-sectional view showing the structure of a DPF applied to a conventional diesel engine.

Referring to FIG. 1, the DPF is mainly designed in a honeycomb structure, and consists of air holes with one side blocked. Exhaust gas entering the open air hole is moved to the air passage of the next compartment through small holes formed by the walls of the ceramic material that divide the holes between the holes because the opposite end is blocked, and exits through the hole drilled in the opposite direction.

In this process, fine contaminants are filtered out on the wall partitioning between the holes, and filtration is performed. In other words, the multiple walls that divide the DPF in a honeycomb shape function as filters, and therefore, as time passes, collected soot, other fine dust, and carbon powder cannot help but accumulate in the walls and holes that act as filters. .

As fine pollutants accumulate, the filtration efficiency for pollutants decreases, and combustion in the engine cylinder is hindered due to back pressure. That is, if nitrogen oxides and particulate matter continue to accumulate in the DPF over time, the flow area through which the exhaust gas passes is narrowed, increasing the engine back pressure, and eventually degrading the engine's output and the processing performance of the aftertreatment device.

Accordingly, it is absolutely required to restore performance by removing nitrogen oxides and particulate matter in the DPF, which is generally referred to as DPF regeneration (regeneration, hereinafter, abbreviated as 'regen'). DPF regeneration is performed by raising the temperature of the exhaust gas discharged after combustion by increasing the number of revolutions of the engine, or removing particulate matter adsorbed/collected in the device by burning them using a separate regeneration device.

When the adsorption/accumulation amount increases or a certain period elapses, the accumulation amount is detected through a differential pressure sensor, the accumulation amount is predicted according to the fuel amount calculation, or the set cycle previously input to the ECU is determined. Of course, the system is configured to enable manual regen by the driver in case regeneration is omitted due to device errors, driving conditions, or environments.

In regenerating the DPF by increasing the temperature of the exhaust gas, the minimum temperature T1 of the exhaust gas before the DPF required is approximately 300 degrees Celsius. Therefore, it is necessary to rapidly increase the temperature of the front end of the DPF to the minimum temperature T1 with the start of regeneration. This is because the initial HC (hydrocarbon) slip in the DOC in front of the DPF becomes a problem until the minimum temperature (T1) is reached.

However, since manual regen is generally performed in a no-load state while the vehicle is stopped, there is a problem in that it is difficult to quickly raise the exhaust gas temperature to the minimum temperature required for regeneration. The problem of HC (hydrocarbon) slip in DOC ahead of the DPF continues to emerge.

Korean Patent Publication No. 10-2012-0112850 (published on October 11, 2012)

The problem to be solved by the present invention is that the exhaust gas temperature can be quickly raised to the temperature required for DPF regeneration, and through this, DPF forced regeneration of a work vehicle that can effectively respond to the slip of HC (hydrocarbon) in the early stage of regeneration It is intended to provide systems and methods.

Another problem to be solved by the present invention is a work vehicle capable of preventing excessive consumption of fuel during forced regeneration while sufficiently securing exhaust heat necessary for regeneration by enabling the adjustment of engine load depending on the situation during forced regeneration. It is intended to provide a DPF forced regeneration system and method.

According to one aspect of the present invention as a means for solving the problem,

DPF (Diesel Particle Filter, For forced regeneration (Manual Regen) of diesel particle filter),

A manual regen switch for generating a regeneration switching signal for switching to a regeneration mode;

a hydraulic discharge line through which the hydraulic oil discharged by the hydraulic pump is moved;

a hydraulic supply line for supplying the hydraulic oil intermittently provided from the hydraulic discharge line to the actuator;

On the bypass line connecting the hydraulic discharge line installed at the inlet side of the variable valve and the hydraulic supply line installed at the outlet side of the variable valve and the flow path variable valve controlling the movement of hydraulic oil between the hydraulic discharge line and the hydraulic supply line. Regeneration control valve unit consisting of a pressure control valve; and

Provides a DPF forced regeneration system for a work vehicle including an ECU that controls the variable valve from the regeneration conversion signal generated by the forced regeneration switch so that the hydraulic oil passes through the bypass line.

In the DPF forced regeneration system of a work vehicle according to an aspect of the present invention, the ECU may control the opening and closing or opening angle of the variable valve by outputting a control signal with a different value according to exhaust gas temperature information obtained from a temperature sensor. there is.

At this time, the ECU detects the temperature change rate from the temperature change of the exhaust gas over time, and when the temperature change rate is faster than the preset rate, the ECU increases the opening angle of the variable valve according to the temperature change rate to increase the engine It can be set to lower the load.

According to another aspect of the present invention as a means for solving the problem,

As a method for forced regeneration (Manual Regen) of the DPF (Diesel Particle Filter, diesel particle filter) installed in the diesel engine exhaust line,

A regeneration mode conversion step of converting an operating state of an engine into a DPF regeneration mode from a regeneration conversion signal generated by a manual regen switch;

a temperature raising step of increasing exhaust gas temperature by controlling a variable valve of a regeneration control valve unit to increase a circuit pressure of a hydraulic circuit;

a regeneration step of burning and removing PM (particulate harmful substances) collected in the DPF using high-temperature heat raised to a target temperature through the temperature raising step; and

A normal mode conversion step of converting an engine operating state to a normal mode after completing DPF regeneration; including,

Provided is a method for forcibly regenerating a DPF of a work vehicle including a load adjustment process of adjusting an engine load by adjusting the opening or closing angle of the variable valve according to exhaust gas temperature information obtained from a temperature sensor in the temperature raising step.

At this time, in the load adjusting process, the temperature change rate is detected from the temperature change of the exhaust gas over time, and if the temperature change rate is faster than the preset rate, the control of lowering the engine load by increasing the opening angle of the variable valve can be performed. .

According to the system and method for forced DPF regeneration of a work vehicle according to the present invention, the exhaust gas temperature can be rapidly raised to the temperature required for DPF regeneration by artificially increasing the engine load by increasing the circuit pressure of the hydraulic circuit. It is possible to solve the slip problem of initial HC (hydrocarbon).

In addition, the engine load can be adjusted through the ECU's variable valve control according to the situation during regeneration, so that sufficient exhaust heat required for forced regeneration is secured, but in situations where excessive load is not required, the load value is lowered to cause excessive fuel consumption during forced regeneration. This can minimize the loss of fuel economy.

1 is a cross-sectional view showing a DPF structure applied to a conventional diesel engine exhaust gas post-treatment device.
2 is a schematic configuration diagram of a DPF forced recovery system of a work vehicle according to an embodiment of the present invention.
Figure 3a is a diagram showing the flow of hydraulic oil in a normal driving situation (normal mode).
Figure 3b is a diagram showing the hydraulic oil flow in the forced regeneration mode.
4 is a flow chart applied for forced regeneration;

Hereinafter, preferred embodiments of the present invention will be described in detail.

Terms used in the specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise" or "having" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other features or It should be understood that the presence or addition of numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Also, terms such as first and second may be used to describe various components, but the components should not be limited by the terms. These terms are only used for the purpose of distinguishing one component from another.

In addition, terms such as "...unit", "...unit", and "...module" described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. can

In the description with reference to the accompanying drawings, the same reference numerals will be given to the same components, and overlapping descriptions thereof will be omitted. In addition, in the description of the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

Hereinafter, a work vehicle referred to in describing the present invention is equipped with a diesel engine, has a hydraulic pump driven by power output from the diesel engine, and has a hydraulic actuator operated by hydraulic oil discharged from the hydraulic pump. It may be a vehicle, for example, a tractor, and the present invention proposes a forced regeneration system of a DPF applied to such a work vehicle.

2 is a schematic configuration diagram of a DPF forced recovery system for a work vehicle according to an embodiment of the present invention.

Referring to FIG. 2, the DPF (70) forced regeneration system of a working vehicle according to an embodiment of the present invention is a DPF (Diesel Particle Filter, diesel particle filter) installed in the exhaust line of a diesel engine (50) for filtering fine pollutants. It is for manual regen of the filter 70) and largely includes a manual regen switch 10, a regeneration control valve unit 30, and an ECU 20.

The forced regen switch (Manual Regen Switch, 10) generates an electrical regeneration conversion signal for switching to the manual regen mode at the time when switch operating force is input. The regeneration switching signal generated by the forced regeneration switch 10 is transmitted to the ECU 20, and the ECU 20 converts the system state to the forced regeneration mode for recovering the performance of the DPF 70 from the time the signal is input. .

The regeneration control valve unit 30 controls the movement of the hydraulic oil so that the hydraulic oil discharged from the hydraulic pump 40 under the control of the ECU 20 can be supplied to the actuator 60 through a normal path (FIG. 3 (refer to the normal mode of (a)), the normal movement of the pressure oil discharged by the hydraulic pump 40 is limited to increase the exhaust gas temperature, thereby increasing the circuit pressure in the hydraulic circuit (forced regeneration mode of FIG. 3 (b)). Reference).

The regeneration control valve unit 30 is specifically, a flow path variable variable valve 32 for controlling the movement of hydraulic oil between the hydraulic discharge line 45 and the hydraulic supply line 48, and the inlet side of the variable valve 32 It is composed of a pressure control valve (Pressure control valve, 34) on the bypass line (33) connecting the hydraulic discharge line (45) installed in and the hydraulic supply line (48) installed on the outlet side of the variable valve (32).

The variable valve 32 may be an on/off type solenoid valve operated by an electrical signal output from the ECU 20, and the pressure control valve 34 is a relief valve can be

The hydraulic oil discharged by the hydraulic pump 40 is supplied to the variable valve 32 through the hydraulic discharge line 45 . In addition, the hydraulic supply line 48 intermittently receives hydraulic oil from the hydraulic discharge line 45 according to the opening and closing state of the variable valve 32 under the control of the ECU 20, and the actuator 60 ) to supply Specifically, hydraulic oil is supplied to the actuator 60 only when the discrete valve is opened under the control of the ECU 20 .

The ECU 20 controls the variable valve 32 from the regeneration switching signal generated by the forced regeneration switch 10 to limit the flow of hydraulic oil discharged from the hydraulic pump 40 . Specifically, the control of switching the variable valve 32 to the CLOSE position together with the start of forced regeneration (when the regeneration switching signal is input) restricts the movement of hydraulic oil and increases the circuit pressure of the hydraulic circuit.

In other words, when forced regeneration (Manual Regen) is started, the ECU 20 increases the circuit pressure of the hydraulic circuit through the variable valve 32 to artificially increase the load on the engine 50 and through this, the engine 50 burns. The temperature of the exhaust gas generated after the exhaust gas is controlled so that it can quickly rise to the minimum temperature (approximately 300 degrees Celsius) required for regeneration of the DPF (70).

Referring to Figure 3 showing the moving state of the pressure oil in a specific mode will be looked at in more detail.

Figure 3a is a diagram showing the flow of hydraulic oil in a normal operating situation (normal mode), in the normal mode (Normal mode), the variable valve 32 is maintained in an open state. Accordingly, the hydraulic oil is supplied to the actuator 60 through an open hydraulic line leading to the hydraulic discharge line 45, the variable valve 32, and the hydraulic supply line 48, and can be used to drive the actuator 60.

FIG. 3B shows a situation in the forced regeneration mode. When forced regeneration is initiated by the driver or operator's intentional manipulation of the forced regeneration switch 10 (when the regeneration conversion signal is input), the variable valve 32 is controlled by the ECU 20. It is switched to the closed position, and thus the flow of hydraulic oil supplied from the hydraulic discharge line 45 to the hydraulic supply line 48 through the variable valve 32 is blocked.

Accordingly, in a state where the actuator 60 is not manipulated, the high-pressure oil is provided to the input side of the variable valve 32 through the hydraulic discharge line 45, but the circuit pressure rises as the hydraulic oil is not consumed. The driving load of the pump 40 increases and eventually the engine 50 is loaded, and as a result, the time taken for the temperature of the exhaust gas to reach the minimum temperature required for regeneration of the DPF 70 is significantly reduced.

Of course, in this case, the circuit pressure is maintained at a specific level by the pressure control valve 34. That is, when the pressure of the hydraulic discharge line 45 reaches the set circuit pressure, the pressure control valve 34 is opened and some of the hydraulic oil is moved to the hydraulic supply line 48 side through the bypass line 33, so that the circuit pressure reaches a certain level. It can be maintained, and in the end, device malfunction or breakdown due to excessive increase in circuit pressure is prevented.

In raising the temperature at the front end of the DPF (70) to the minimum temperature required for regeneration of the DPF (70) by artificially increasing the circuit pressure in a way to limit the movement of the pressure oil, the condition at the time when the regeneration is executed, preferably Depending on external environmental conditions, there are cases in which the temperature can be quickly brought up to the minimum temperature without increasing the load of the engine 50 .

The engine 50 has a characteristic of consuming a lot of fuel in proportion to the size of the load. Therefore, if the engine 50 can be quickly raised without increasing the load, it is necessary to configure the system so that unnecessary fuel is not consumed excessively by reducing the load or shortening the load operation time in terms of efficiency and fuel efficiency of the system. advantageous in

For example, in the summer season when the air temperature is high, the exhaust gas temperature can be quickly increased to the minimum temperature without increasing the load of the engine 50 . Therefore, at this time, it is preferable to adjust the load of the engine 50 by controlling the opening amount of the variable valve 32 with the ECU 20 so that exhaust heat necessary for regeneration is sufficiently secured and fuel is not excessively consumed during regeneration.

To this end, in the DPF 70 forced regeneration system according to one aspect of the present invention, the ECU 20 performs the exhaust gas temperature information obtained from a temperature sensor (not shown) mounted at an arbitrary position in the exhaust line. A control signal having a different value may be output so that the load of the engine 50 can be adjusted by adjusting the opening angle of the variable valve 32 in a completely closed or partially opened state in some cases.

Preferably, the temperature change rate is detected from the temperature change of the exhaust gas over time in the forced regeneration mode, and when the temperature change rate is faster than the preset rate, the variable valve 32 is switched to the open side according to the temperature change rate. Alternatively, it may be set so that the control of gradually lowering the load of the engine 50 is performed by gradually increasing the opening angle.

For example, in summer, when the speed of change of the exhaust gas temperature during regeneration proceeds faster than usual due to high atmospheric temperature, the load of the engine 50 is appropriately lowered by increasing the opening amount of the variable valve 32, which is necessary for forced regeneration. This is to prevent excessive consumption of fuel as the load state of the engine 50 is maintained at the highest value during the forced regeneration process while sufficiently securing exhaust heat.

Next, a DPF forced regeneration process performed by the forced regeneration system configured as described above will be described below.

4 is a flowchart for forced regeneration. Manual regen is largely composed of a regeneration mode switching step (S100), a temperature raising step (S200), a regeneration step (S300), and a normal mode switching step (S400). The temperature raising step (200) may include a load adjustment process (S210) of adjusting the engine load by adjusting the opening/closing or opening angle of the aforementioned variable valve according to the exhaust gas temperature information obtained from the temperature sensor.

The regeneration mode conversion in the regeneration mode switching step (S100) is the time when the regeneration conversion signal generated by the forced regeneration switch is transmitted when there is an intentional manipulation of the aforementioned manual regen switch by the driver or operator. It can be implemented by switching the operating state of the engine and system to the DPF regeneration mode according to the regeneration start command output by the ECU.

When the regeneration mode is entered, the temperature raising step (S200) of quickly raising the temperature of the exhaust gas to the minimum temperature required for DPF regeneration is continuously performed. By restricting the normal movement of the pressurized oil, control is performed to increase the exhaust gas temperature by artificially increasing the circuit pressure of the hydraulic circuit.

In other words, as soon as manual regen starts, the ECU controls the variable valve to increase the circuit pressure in the hydraulic circuit, thereby artificially increasing the load on the engine. so that it can be quickly raised to the minimum temperature required for the

The load adjustment process (S210) performed in the temperature raising process (S200) may be a process of adjusting the engine load by adjusting the opening/closing or opening angle of the variable valve according to the exhaust gas temperature information obtained from the temperature sensor. That is, the circuit pressure is adjusted through state control of the variable valve based on the exhaust gas temperature information, so that the engine load can be adjusted eventually.

For example, if the speed of change of the exhaust gas temperature in the heating step (S200) is too fast compared to normal due to high air temperature in summer, the opening angle of the variable valve is gradually increased to appropriately lower the engine load value, so that the exhaust heat required for forced regeneration is While sufficiently secured, excessive fuel consumption is prevented as the engine load value is maintained at the maximum value during the forced regeneration process.

On the other hand, in the regeneration step (S300), similar to the generally known regeneration, a process of burning and removing PM (particulate harmful substances) collected in the DPF is performed using the high-temperature heat raised to the target temperature through the above-described temperature raising step. When the DPF regeneration state reaches the target level, the control (S400) of completing the DPF regeneration and converting the engine operation state to the original normal mode is performed by the ECU.

According to the forcible DPF regeneration system and method of the working vehicle according to the present invention described above, the exhaust gas temperature can be rapidly raised to the temperature required for DPF regeneration by artificially increasing the engine load by increasing the circuit pressure of the hydraulic circuit, Through this, it is possible to solve the slip problem of HC (hydrocarbon) at the initial stage of regeneration.

In addition, the engine load can be adjusted through the ECU's variable valve control according to the situation during regeneration, so that sufficient exhaust heat required for forced regeneration is secured, but in situations where excessive load is not required, the load value is lowered to cause excessive fuel consumption during forced regeneration. This can minimize the loss of fuel economy.

In the above detailed description of the present invention, only special embodiments have been described accordingly. However, it should be understood that the present invention is not limited to the particular forms mentioned in the detailed description, but rather it is understood to include all modifications, equivalents and substitutes within the spirit and scope of the present invention as defined by the appended claims. It should be.

10 : Manual regen switch
20: ECU
30: regeneration control valve unit
32: variable valve
33: bypass line
34: pressure control valve
40: hydraulic pump
45: hydraulic discharge line
48: hydraulic supply line
50: engine
60: actuator
70 : DPF (Diesel Particle Filter)

Claims (5)

DPF (Diesel Particle Filter, For forced regeneration (Manual Regen) of diesel particle filter),
A manual regen switch for generating a regeneration switching signal for switching to a regeneration mode;
a hydraulic discharge line through which the hydraulic oil discharged by the hydraulic pump is moved;
a hydraulic supply line for supplying the hydraulic oil intermittently provided from the hydraulic discharge line to the actuator;
On the bypass line connecting the flow path variable valve for controlling the movement of hydraulic oil between the hydraulic discharge line and the hydraulic supply line, and the hydraulic discharge line installed at the inlet side of the variable valve and the hydraulic supply line installed at the outlet side of the variable valve. Regeneration control valve unit consisting of a pressure control valve; and
and an ECU controlling the variable valve from the regeneration conversion signal generated by the forced regeneration switch so that the hydraulic oil passes through the bypass line.
According to claim 1,
The ECU outputs a control signal with a different value according to the exhaust gas temperature information obtained from the temperature sensor to adjust the opening or closing angle of the variable valve and controls the engine load.
According to claim 2,
The ECU detects the temperature change rate from the temperature change of the exhaust gas over time, and when the temperature change rate is faster than the preset rate, increases the opening angle of the variable valve according to the temperature change rate to lower the engine load. DPF compulsory regeneration system of the work vehicle.
As a method for forced regeneration (Manual Regen) of the DPF (Diesel Particle Filter, diesel particle filter) installed in the diesel engine exhaust line,
A regeneration mode conversion step of converting an operating state of an engine into a DPF regeneration mode from a regeneration conversion signal generated by a manual regen switch;
a temperature raising step of increasing exhaust gas temperature by controlling a variable valve of a regeneration control valve unit to increase a circuit pressure of a hydraulic circuit;
a regeneration step of burning and removing PM (particulate harmful substances) collected in the DPF using high-temperature heat raised to a target temperature through the temperature raising step; and
A normal mode conversion step of converting an engine operating state to a normal mode after completing DPF regeneration; including,
The temperature raising step includes a load adjustment process of adjusting an engine load by adjusting the opening or closing or opening angle of the variable valve according to exhaust gas temperature information obtained from a temperature sensor,
In the load adjustment process, the temperature change rate is detected from the temperature change of the exhaust gas over time, and when the temperature change rate is faster than the preset rate, the opening angle of the variable valve is increased to lower the engine load. How to force DPF regeneration.
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