KR20120071260A - Active regeneration dpf system using non-working load and method of the same - Google Patents

Abstract

PURPOSE: A vacuum compressor and a turbine generator structure are provided to rapidly increase the temperature of exhaust gas by applying non-work loads to an engine which are not the real work loads of construction equipment. CONSTITUTION: A vacuum compressor and a turbine generator structure comprise an engine(110), a DPF(diesel particle filter)(130), a diesel oxidation catalyst unit(140), a fuel feeding unit(150), and a unit for forcibly generating loads. The DPF is placed in an exhaust line(120), in which exhaust gas from the engine is discharged outside. The diesel oxidation catalyst unit is placed in front of the DPF. The fuel feeding unit injects the fuel, which exoergic-reacts with DOC(Diesel oxidation catalysts) into the front of the DOC unit. The unit for forcibly generating the loads provides non-work loads to the engine. The unit for forcibly generating the loads comprises a pan pump(160). The pan pump randomly discharges working oil when the DPF is forcibly operated while the pan pump generates the non work load. Consequently, the engine discharges the exhaust gas with a higher temperature than the predetermined temperature.

Description

Active regeneration DPF system using non-working load and method of the same}

The present invention relates to a DPF forced regeneration system of an engine, and more specifically, to a DPF forced regeneration, wherein the DPF forced regeneration is performed quickly by providing a non-work load arbitrarily to the engine even when substantial work of the construction machine is stopped. A reproduction system and method thereof are provided.

Engines used in construction machinery are required to meet various regulations and standards. One such criterion is the reduction of pollutants such as NOx and Particulate Matter (PM) contained in exhaust gases, which can be a major environmental standard along with noise regulations in the use of construction equipment. have.

In order to meet these environmental standards, engines using various means such as Exhaust Gas Recirculation (EGR) and Diesel Particulate Filter (DPF) devices are commonly used.

Here, the diesel particulate filter (DPF) refers to a filter capable of collecting and filtering particulate dust (soot), which is a particulate matter including soot in a muffler, on a path through which exhaust gas from an engine is discharged. Also referred to as a device equipped with such a filter.

Such a filter requires a process of removing particulate matter collected therein periodically or arbitrarily according to the amount collected, which is commonly referred to as 'DPF regeneration' or 'burning off'.

Such regeneration can be classified into passive regeneration and active regeneration according to its implementation.

DPF natural regeneration, for example, refers to the combustion of fine dust trapped in the filter by the temperature of the exhaust gas raised during the operation of a construction machine, or a small amount of fuel on a path through which the exhaust gas is discharged during operation of the construction machine. By means of the injection of the diesel oxidation catalyst (DOC; Diesel Oxidation Catalyst (DOC) pre-positioned on this path and the injected fuel generates an exothermic reaction to generate a higher heat, thereby burning the collected fine dust).

Next, the DPF forced regeneration means that the driver forcibly drives the engine of the construction machine without actually performing work to discharge the exhaust gas, and based on the temperature of the exhaust gas, The fuel is exothermic to the diesel oxidation catalyst device (DOC), which is also pre-positioned on the exhaust path, causing the dust to be collected in the filter by raising the temperature of the exhaust gas to a temperature necessary for combustion (regeneration) of the fine dust. The way of burning.

Referring to FIG. 1, a schematic configuration of a conventional DPF forced regeneration system is as follows. According to FIG. 1, a conventional DPF forced regeneration system 100 includes a diesel particulate filter (DPF) 30 formed on an engine 10 having a turbocharger 12 and an exhaust path 20 through which exhaust gas is discharged. And the DOC (diesel oxidation catalyst device) 40 at the front end of the DPF, and by the fuel input means 50 and the engine 10 which inject a small amount of fuel into the front end of the DOC in the exhaust path 20. And a pump 60 driven. In the case of DPF forced regeneration, a substantial workload is not generated, so details thereof are omitted in the drawings.

In the case of forced regeneration of the DPF having the system of such a configuration, since the construction machine is in a stopped state, the actual work of the construction machine, such as driving a front work means such as a boom or a bucket, or driving a vehicle back and forth, for example. The engine is driven in an idle state (i.e., a low rpm) which receives only a minimum load, and thus the temperature of the exhaust gas discharged in the idle state is not easily increased. That is, the exhaust gas from the engine which started to be driven in the idle state has a relatively low temperature compared with the operation.

On the other hand, in order to burn (DPF regeneration) the fine dust collected in the diesel fine dust filter (DPF) by the DPF forced regeneration method, between the DOC disposed on the exhaust path and the fuel introduced into the exhaust path at the front end of the DOC. An exothermic reaction must occur and this exothermic reaction is possible above a predetermined temperature (about 235 ° C.), which requires considerable time for the exhaust gas to be heated to this predetermined temperature in the case of forced regeneration of DPF without substantial workload. .

Normally, the engine emits exhaust gas at a higher temperature when the engine is driven under a load than the idle driving state. However, unlike the case of natural regeneration, in the case of forced regeneration, the engine is driven from the stopped state of the construction machine to a substantially no-load state (idle state) until the temperature of the exhaust gas is raised to a predetermined temperature at which the exothermic reaction of the DOC is possible. It takes time. For example, it is known that it takes about 30 minutes to about 1 hour for the DPF forced regeneration of construction machinery.

Due to the high cost of purchasing construction equipment, most construction equipment is usually rented on a time or date basis, unlike the DPF natural regeneration process, which can be done in parallel with the work, the DPF forced to spend time without work. The refurbishment process has increased the cost of renting construction equipment. In addition, even if the construction machinery was not rented, the fact that the work had to be suspended for a considerable amount of time due to the forced regeneration of the DPF would reduce the overall efficiency of the construction machinery working process. In addition, since the engine has to be continuously driven during the long-lasting DPF forced regeneration process, there is a difficulty in proportionally increasing fuel consumption according to the duration of DPF forced regeneration.

It is an object of the present invention to provide a DPF forced regeneration system and method which can be efficiently performed by imparting any non-work load to the engine and rapidly raising the temperature of the exhaust gas.

It is still another object of the present invention to provide a DPF forced regeneration system and method capable of minimizing the amount of fuel consumed in connection with forced regeneration by performing a rapid DPF forced regeneration.

In order to achieve this object, an embodiment of the present invention includes an engine; A diesel particulate filter (DPF) disposed on an exhaust path through which exhaust gas from the engine is discharged to the outside; A diesel oxidation catalyst device (DOC) disposed in front of the DPF on the exhaust path; Fuel injecting means for injecting a fuel causing an exothermic reaction with the DOC at a predetermined temperature to the front end of the DOC in the exhaust path; And forced load generating means for providing a non-work load to the engine, wherein the forced load generating means is constituted by the fan pump 160, and during the forced regeneration of the DPF, if the fan pump does not cause substantial work of the construction machine, And optionally controlled to discharge the maximum flow rate of the working oil to create a non-work load, whereby the engine discharges exhaust gas above a predetermined temperature.

As such, in the case of forced regeneration of the DPF, the exothermic reaction between the DOC and the fuel is possible because the temperature of the exhaust gas can be increased to a predetermined temperature or more in a shorter time than that when the engine is driven under a non-work load and driven in an idle state. The DPF regeneration (combustion removal) can be efficiently performed by the high temperature generated thereby.

In addition, the system of the present invention uses a variable fan pump as the fan pump 160, and at the time of forced regeneration of the DPF, the fan pump discharges the working oil at the maximum flow rate by arbitrarily adjusting the proportional current signal transmitted to the variable fan pump. It is characterized by.

The system of the invention is also characterized in that the fan pump is connected with at least one separately driven fan motor which is not directly connected to the engine.

The present invention provides a method of forcibly regenerating a DPF in the aforementioned DPF forced regeneration system, comprising: (a) driving an engine in an idle state; (b) measuring the temperature of the exhaust gas on the exhaust path; (c) when the measured temperature is below a predetermined temperature, driving the forced load generating means to impart a non-work load to the engine; (d) the engine releasing higher hot exhaust gases by non-work loads; (e) stopping the driving of the forced load generating means if the forced load generating means is being driven when the measured temperature exceeds a predetermined temperature; (f) performing DPF forced regeneration; And (g) repeating steps (b) to (f) until the regeneration of the DPF is completed, wherein the exothermic reaction is promoted by the high temperature exhaust gas, thereby forcing the DPF forced regeneration to be efficiently performed. DPF forced regeneration method using non-work load is provided.

According to the present invention, a DPF forced regeneration system and method that can be efficiently performed by rapidly raising the temperature of the exhaust gas by applying an arbitrary non-work load to the engine during the DPF forced regeneration, rather than the actual workload of the construction machine. Can be provided.

In addition, according to the present invention, it is possible to provide a DPF forced regeneration system and method that can minimize the amount of fuel consumed in connection with forced regeneration by performing a rapid DPF forced regeneration.

1 is a block diagram showing an example of a conventional DPF forced regeneration system;
2 is a block diagram illustrating a DPF forced regeneration system according to an embodiment of the present invention;
3 is a block diagram illustrating a DPF forced regeneration system according to another embodiment of the present invention; And
4 is a flowchart illustrating a DPF forced regeneration method according to another embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, preferred embodiment of this invention is described with reference to drawings.

2 is a block diagram illustrating a DPF forced regeneration system according to an embodiment of the present invention. Specifically, the DPF forced regeneration system 200 of this embodiment includes a diesel oxidation catalyst device (DOC) on the engine 110 equipped with the turbocharger 112 and the exhaust path 120 of the exhaust gas discharged therefrom. 140 and the diesel particulate filter (DPF) 130 are arranged in turn and includes a fuel injection means 150 for injecting fuel on the exhaust path in front of the DOC 140. In addition, the engine 110 includes, for example, a fan for rotating the cooling fan 174 together with a main pump (not shown) for supplying hydraulic oil to various working stages (for example, a boom, a bucket, a swing motor, and the like) of the construction machine. A fan pump (F / P; Fan Pump) 160 for supplying hydraulic oil to the motor 172 is connected. The fan pump 160 may be a variable fan pump and may be controlled through a proportional control signal 164 transmitted through a control means such as a proportional control valve 162.

In this embodiment, the cooling fan 172 applied to the oil cooler 170 may be rotated by the fan motor 172 driven by receiving hydraulic oil from the fan pump 160. In addition, the cooling fan 184 applied to the radiator 180 may be connected directly to the engine 110 and rotate without including a separate fan motor. In this embodiment, the oil cooler 170 is shown via fan pump 160 and the radiator 180 is directly connected to the engine 110, but is not limited thereto, and these elements may be in various forms. Note that it may be configured.

In the drawings, the hydraulic driving part including the main pump and each working stage (boom, bucket, swing motor, etc.) and a plurality of control valves corresponding to each working stage is omitted. Since the stage is not substantially driven, a detailed description thereof will be omitted below.

In such a system 200, if DPF forced regeneration is performed, the engine 110 is driven in an idle state (i.e., low rpm) since no substantial workload occurs. As described above, in order to perform DPF forced regeneration more quickly, a predetermined temperature (eg, about 235 ° C.), which is a reference for exothermic reaction between the DOC 140 and the fuel, is determined based on the temperature of the exhaust gas discharged from the engine 110. It is required to increase the above, and thus the present invention can quickly raise the temperature of the exhaust gas by providing a non-work load to the engine 110 rather than a substantial work.

In the present invention, the term 'non-work load' means any forced load provided to the engine 110 without actually driving each work stage of the construction machine. That is, in this embodiment, the fan pump 160 which is not connected to each working stage can be controlled to discharge the hydraulic fluid of the maximum flow rate, that is, the control signal S to the proportional control valve 162 controlling the fan pump 160. ), The proportional control signal 164 transmitted therefrom can be arbitrarily controlled to the maximum, whereby the fan pump continuously discharges the hydraulic fluid at the maximum flow rate regardless of the actual work. As such, while the fan pump 160 discharges the hydraulic fluid at the maximum flow rate, a so-called 'non-work load', which is any forced load, is thus provided to the engine 110, through which the engine 110 is driven to idle Compared to the state it is possible to increase the temperature of the exhaust gas more quickly.

When the exhaust gas reaches a predetermined temperature, that is, about 235 ° C., the exothermic reaction between the DOC 140 and the fuel is accelerated by the temperature of the exhaust gas, and DOC ( Soot, which has been collected in the DPF 130 arranged at the rear end of the 140, may be burned off. That is, DPF regeneration can be performed.

As such, in this embodiment, at most arbitrary control of the proportional control signal transmitted to the fan pump for driving the rotation of a plurality of cooling fans driven independently of each work stage (e.g., boom, bucket, and swing motor, etc.). Accordingly, the fan pump 160 provides the non-work load to the engine 110 by causing the fan pump 160 to discharge the hydraulic fluid at the maximum flow rate, and thus the engine 110 is in a conventional idle state through the load. It is characterized in that the exhaust gas of a predetermined temperature for promoting the exothermic reaction of the high temperature, preferably DOC 140 more quickly than when driven to.

Next, FIG. 3 shows an embodiment similar to FIG. 2, wherein only the oil cooler 170 and the radiator 180 are arranged to rotate by fan motors 172 and 182 which are separately driven. That is, in the system 200 of FIG. 2, the radiator 180 applies a cooling fan directly connected to the engine, whereas in the system 200 ′ of FIG. 3, the radiator 180 is a fan pump like the oil cooler 170. It is different in that it operates using a separate fan motor 182 that is driven and supplied with hydraulic fluid by 160.

That is, FIG. 3 is similar to the configuration of FIG. 2 except that all cooling fans 174 and 184 shown in the drawing are configured to rotate by fan motors 172 and 182 which are all driven by the fan pump 160. Substantially the same, it can be understood as a modification of the embodiment of FIG. 2. In addition, although the fan motors 172 and 182 driven by the fan pump 160 in the above embodiments are only two illustrated for each of the oil cooler 170 and the radiator 180, it is not limited thereto. Do. In addition, the fan pump 160 may be configured to supply hydraulic oil required when operating a joystick (not shown) in the cockpit, for example, or hydraulic oil used in a steering device and a braking device of a construction machine.

However, it is not required that the actual work of the construction machine occurs during the forced regeneration of the DPF, and thus, the fan pump 160 may be operated without performing actual work (such as driving a boom or a bucket or steering or braking the construction machine). The present invention can be applied within a range capable of discharging the hydraulic fluid of the maximum flow rate. For example, when performing DPF forced regeneration, a separate cooling fan may be arranged to cool the heat generated in the engine room, which is also driven by a fan motor connected in the fan pump 160 of the present invention. Could be.

Next, FIG. 4 is a flowchart showing a DPF forced regeneration method according to another embodiment of the present invention.

According to Fig. 4, this embodiment starts with the engine being driven in the idle state to perform the DPF forced regeneration (S100). In order to perform DPF regeneration, a high temperature of, for example, 6-700 ° C. capable of burning off (regeneration) of fine dust (fine particles including soot, etc.) trapped in the DPF is required, which is a DOC in DPF forced regeneration. It can be achieved by the exothermic reaction between and the fuel injected. Therefore, the forced regeneration of DPF can be performed only when the temperature of the exhaust gas reaches a predetermined temperature of about 235 ° C., which can promote the exothermic reaction of DOC.

Thus, the temperature of the exhaust gas at the front end of the DOC on the exhaust path is measured (S110). The measured temperature is compared with a predetermined temperature (about 235 ° C.) which may promote an exothermic reaction (S120). As a result of the comparison, if the measured temperature is less than or equal to the predetermined temperature, as described above, the forced load generating means composed of the fan pump is driven to generate a non-work load and provide it to the engine (S130). The engine may be driven under a non-work load to raise the temperature of the exhaust gas faster than the idle state without a substantial work load such as driving a boom or a bucket (S140). When the temperature of the exhaust gas rises to a predetermined temperature at which the exothermic reaction of the DOC can be promoted, an exothermic reaction between the DOC and the fuel generates a higher temperature (about 6-700 ° C.) higher than the predetermined temperature (about 235 ° C.). The fine dust collected in the DPF is burned out (regenerated) (S150). After confirming whether or not the reproduction is completed (S160), the DPF forced regeneration method is terminated.

In addition, if it is determined in the above-described measurement temperature comparison step (S120) that the measured temperature exceeds a predetermined temperature, it is determined whether the forced load generating means is being driven, and if it is being driven, the driving force generating means is stopped to stop the non-working. The generation of the load is stopped (S170). That is, it is possible to prevent unnecessary fuel consumption by removing the non-work load provided to the engine so that the engine is driven in the idle state. For example, providing a non-work load to the engine is intended to raise the temperature of the exhaust gas to a predetermined temperature that can facilitate the exothermic reaction of the DOC. There is no need to provide a 'non-workload' to the engine. Of course, by continuously measuring the temperature of the exhaust gas in front of the DOC and subsequent steps (S110 to S160) until the regeneration is completed, it is determined whether to provide a non-work load in real time, and accordingly unnecessary fuel Reduce the consumption of

As described above, the present invention provides a substantial load of the construction machinery with the engine so that the exhaust gas temperature can be raised to a predetermined temperature more quickly than the conventional case in which the engine is driven in the idle state when the DPF is forcedly regenerated. By providing a non-work load, the time required for forced regeneration of the DPF can be shortened, while at the same time reducing fuel consumption. In addition, by selectively providing a non-work load according to the temperature of the exhaust gas, when the temperature of the exhaust gas exceeds a predetermined temperature, the provision of the non-work load is blocked, resulting in reduction of fuel consumption. .

100, 200: DPF forced regeneration system
10, 110: engine (ENG)
12, 112: turbocharger (T / C)
20, 120: exhaust path
30, 130: Diesel fine dust filter (DPF)
40, 140: Diesel Oxidation Catalyst (DOC)
50, 150: fuel input means
60, 160: pump (fan pump)
162, 262: proportional control valve
164, 264: proportional control signal
170: oil cooler
172, 182: fan motor
174, 184: cooling fan
180: radiator
S: control signal

Claims (4)

Engine 110;
A diesel fine dust filter (DPF) 130 disposed on an exhaust path 120 through which exhaust gas from the engine is discharged to the outside;
A diesel oxidation catalyst device (DOC) 140 disposed in front of the DPF on the exhaust path;
Fuel injection means (150) for injecting fuel causing an exothermic reaction with the DOC (140) at a predetermined temperature to the front end of the DOC in the exhaust path; And
And a forced load generating means for providing a non-work load to the engine 110,
The forced load generating means is constituted by the fan pump 160,
Upon forced regeneration of the DPF, the fan pump 160 is controlled to discharge the hydraulic fluid at a maximum maximum flow rate without causing substantial work of the construction machine, thereby creating a non-work load, so that the engine 110 is at the predetermined temperature. DPF forced regeneration system 200 using a non-work load, which is to discharge the above exhaust gas. The method of claim 1, wherein the fan pump 160 is a variable fan pump,
In the case of forced regeneration of the DPF, the DPF forced regeneration system using the non-work load, wherein the fan pump discharges the working oil at the maximum flow rate by arbitrarily adjusting the proportional current signal 164 transmitted to the variable fan pump. . 3. The system of claim 2, wherein the fan pump (160) is connected with at least one separately driven fan motor (172, 182) that is not directly connected to the engine. A method of forcibly regenerating a DPF in the DPF forced regeneration system according to claim 1,
(a) driving the engine in an idle state;
(b) measuring the temperature of the exhaust gas on the exhaust path;
(c) when said measured temperature is below said predetermined temperature, driving said forced load generating means to impart a non-work load to said engine;
(d) the engine releasing higher hot exhaust gases by non-work load;
(e) stopping the driving of the forced load generating means if the forced load generating means is being driven when the measured temperature exceeds the predetermined temperature;
(f) performing DPF forced regeneration; And
(g) repeating steps (b) to (f) until the regeneration of the DPF is completed;
And, wherein the exothermic reaction is promoted by the high temperature exhaust gas so that the DPF forced regeneration is efficiently performed.

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