JP7637540B2 - Engine-driven generator - Google Patents

Description

The present invention relates to an engine-driven generator that has an exhaust gas aftertreatment device installed in the exhaust passage of a diesel engine that is the driving source of the generator body, and more specifically, to an engine-driven generator that is equipped with a resistor connected to the generator body to apply a load to the engine when increasing the temperature of the exhaust gas introduced into the exhaust gas aftertreatment device.

In engine-driven generators, diesel engines are generally used as the engine that drives the generator itself. However, due to their structure, diesel engines emit more particulate matter (hereinafter referred to as "PM") and nitrogen oxides (hereinafter referred to as " _NOx ") along with the exhaust gas during combustion than gasoline engines.

Because PM and _NOx cause air pollution and health hazards, exhaust gas regulations stipulate regulated values (mass per unit output [g/kWh]) for PM and _NOx emitted by diesel engines.

In order to comply with these emission regulations, an exhaust gas aftertreatment device is provided in the exhaust passage of a diesel engine, which is composed of an oxidation catalyst (hereinafter referred to as "DOC"), a diesel particulate filter (hereinafter referred to as "DPF"), a urea SCR (Selective Catalytic Reduction) device, or a combination of both, thereby reducing the amount of PM and _NOx emissions.

Of these, the DOC generates _NO2 when the temperature of the DOC rises above its activation temperature due to the heat of the exhaust gas, and this _NO2 is used as an oxidizing agent to burn and remove PM.

The DPF is also placed on the secondary side of the DOC mentioned above, and collects PM remaining in the exhaust gas and removes it from the exhaust gas.

Furthermore, the urea SCR device sprays urea water onto the exhaust gas after it has passed through the DOC to generate ammonia ( _NH3 ) through hydrolysis, and then introduces the exhaust gas after the urea water has been sprayed into an SCR catalyst, where the ammonia generated reduces _NOx and breaks it down into harmless nitrogen ( _N2 ) and water ( _H2O ).

Urea SCR devices also typically have a DOC downstream of the SCR catalyst that breaks down the ammonia remaining in the reduction reaction into nitrogen and water.

In this way, the exhaust passage of the engine of an engine-driven generator is provided with the above-mentioned DOC, or an exhaust gas aftertreatment device equipped with the DPF and/or urea SCR device in addition to the DOC, to remove PM and _NOx from the exhaust gas. However, even in an engine-driven generator equipped with such an exhaust gas aftertreatment device, if the engine is operated under low load conditions, for example, and the exhaust gas temperature is maintained at a low level, the following problems occur.

If the engine is operated with the exhaust gas temperature below the activation temperature of the DOC, _NO2 is not produced, PM is not burned by the DOC, and the amount of PM in the exhaust gas cannot be reduced.

Therefore, if this operating condition is maintained for a long period of time, in an exhaust gas aftertreatment device that has a DPF on the secondary side of the DOC, a further problem occurs in which PM accumulates in the DPF, causing it to become clogged.

Furthermore, in a configuration in which a urea SCR device is provided on the secondary side of the DOC, if the exhaust gas temperature is operated below the activation temperature of the DOC, unburned organic matter such as PM that could not be burned in the DOC accumulates on the SCR catalyst, and the temperature of the exhaust gas introduced into the SCR catalyst does not increase. As a result, _NOx reduction in the SCR catalyst is not performed sufficiently, and ammonia-derived impurities adhere to the SCR catalyst, reducing the _NOx reduction performance.

In particular, if the piping from the engine to the exhaust gas aftertreatment device is long, the temperature of the exhaust gas reaching the exhaust gas aftertreatment device will be lower, making it more likely that such PM will be poorly combusted, that PM will accumulate in the DPF, and that the performance of the SCR catalyst will be reduced.

Therefore, in an engine-driven generator having an exhaust gas aftertreatment device equipped with the above-mentioned DOC or a DOC and a DPF and/or a urea SCR device, when the exhaust gas temperature is at a predetermined low temperature, when the engine is continuously operated at a low load for a predetermined period of time, when the amount of PM accumulated in the DPF exceeds a certain amount, and every predetermined cumulative operating time of the engine-driven generator, the exhaust gas temperature is increased to raise the temperature of the DOC in the exhaust gas aftertreatment device to above the activation temperature, thereby promoting the combustion of unburned organic matter in the exhaust gas containing PM, and/or the further increase in exhaust gas temperature accompanying the combustion of such unburned organic matter causes regeneration of the DPF (forced regeneration) which forcibly burns the PM accumulated in the DPF, and cleaning of the SCR catalyst (performance recovery).

To achieve this increase in exhaust gas temperature, an engine-driven generator is equipped with an electrical load known as a "dummy load," which is then connected to the generator body to generate power according to the power consumption of the electrical load, thereby increasing the load on the engine (engine output) and raising the temperature of the exhaust gas.

In the configuration of such an engine-driven generator, the equipment already installed in the engine-driven generator serves as the aforementioned electrical load. In Patent Document 1, which is listed below, an electric heater that heats the engine's cooling water serves as the aforementioned electrical load, and this electric heater is connected to the generator body when regenerating the DPF (see Patent Document 1).

In addition, an engine-driven generator has been proposed that is equipped with a dedicated resistor used to increase the engine exhaust temperature as the aforementioned electrical load. As such a resistor, an engine-driven generator 100 has been proposed that is equipped with a resistor 120 constructed by attaching multiple wire-wound resistance elements 121, each of which has a resistance wire 121b wound in a spiral shape around the outer periphery of a cylindrical core material 121a, in a rectangular frame 122, as shown in Figure 5 (see Figures 2 and 3 of Patent Document 2).

In this way, when an electric heater or resistor is connected to the generator body, the electric heater or resistor 120 generates heat when electricity is applied.

Even if such heat is generated, in a configuration in which the electrical load is an electric heater that heats the engine coolant, such as the engine-driven generator described in the above-mentioned Patent Document 1, the heat generated by the electric heater is exchanged with the engine coolant and dissipated by the radiator, so there is no need to take measures against the heat generation.

However, in a configuration such as that of Patent Document 2, which includes a dedicated resistor 120 used to increase the exhaust temperature of the engine, it is necessary to adopt a configuration for cooling this resistor 120.

For this reason, in the above-mentioned Patent Document 2, as shown in FIG. 6, the resistor 120 is arranged at a position somewhere in the flow path 114 of the cooling air from the cooling fan 152 of the engine 150 to the exhaust port 113 provided in the top panel 112d of the soundproof box 110, so that the juxtaposition plane P of the resistance element 121 is perpendicular to the flow path 114 of the cooling air (see FIG. 2 of Patent Document 2).

In addition, the reference numeral 130 in FIG. 6 denotes an exhaust duct 130 that covers the upper part of the exhaust port 113 described above, which is provided on the top plate of the soundproof box 110 of the engine-driven generator 100.

JP 2016-104974 A JP 2016-17486 A

In the configuration of the engine-driven generator 100 in Patent Document 2, as described above, the juxtaposition plane P of the multiple resistance elements 121 is arranged so as to be perpendicular to the cooling air flow path 114, so that the cooling air can be applied to all of the resistance elements 121 approximately evenly to cool them.

However, when a resistor 120 having such a structure is provided, the cooling air flowing inside the soundproof box 110 encounters a large resistance when passing through the resistor 120, and the flow rate (exhaust air volume) of the cooling air passing through the cooling air flow path 114 and exhausted outside the machine via the exhaust port 113 decreases.

Therefore, if a resistor 120 with the above-mentioned structure is placed in the cooling air flow path 114, the cooling performance of the equipment housed in the soundproof box 110 will deteriorate, and the heat balance performance of the engine-driven generator 100 will be reduced.

The present invention has been made to eliminate the drawbacks of the above-mentioned conventional technology, and aims to provide an engine-driven generator equipped with an exhaust gas aftertreatment device, which has a resistor connected to the generator body in order to raise the temperature of the engine's exhaust gas when activating the DOC installed in the exhaust gas aftertreatment device, regenerating the DPF, cleaning the SCR catalyst, etc., and which can be placed in the above-mentioned cooling air flow path, while suppressing a decrease in the amount of cooling air passing through the cooling air flow path, and therefore a decrease in heat balance performance, and can also be appropriately cooled.

Below, the means for solving the problem are described together with the reference symbols used in the description of the embodiment of the invention. These reference symbols are intended to clarify the correspondence between the description of the claims and the description of the embodiment of the invention, and needless to say, are not used in a restrictive manner in interpreting the technical scope of the present invention.

In order to achieve the above object, the engine-driven generator 1 of the present invention comprises:
An engine-driven generator 1 includes an engine 50 which is a diesel engine, a generator body 70 driven by the engine 50, an exhaust gas after-treatment device 82 provided in an exhaust passage of the engine 50, and a resistor 20 connected to the generator body 70 when increasing the temperature of exhaust gas introduced into the exhaust gas after-treatment device 82.
The resistor 20 is formed as an assembly of a plurality of flat plate-like resistive elements 21 arranged in parallel at a predetermined interval,
The resistor 20 is arranged in the flow path 14 of the cooling air so that the plane 21a of each resistance element 21 always forms a vertical plane parallel to the flow path 14 of the cooling air generated by the cooling fan 52, and exerts a straightening effect on the cooling air which changes direction from the horizontal to the vertical direction (claim 1).

In the engine-driven generator 1 having the above configuration,
The cooling fan 52 is disposed in the soundproof box 10 so that the blowing direction BD of the cooling fan 52 is horizontal, and an exhaust air chamber 10b is provided in the soundproof box 10 to introduce cooling air from the cooling fan 52 and communicate with the outside of the machine via an exhaust air outlet 13 provided in the top plate (top panel 12d) of the soundproof box 10, forming a flow path 14 for the cooling air from the cooling fan 52 to the exhaust air outlet 13,
The resistor 20 can be configured to be housed below the exhaust port 13 so that the plane 21a of each resistive element 21 forms a vertical plane parallel to the blowing direction BD of the cooling fan 52 (Claim 2: see Figures 1 and 2).

In addition, instead of the above configuration,
The cooling fan 52 is disposed in the soundproof box 10 so that the blowing direction BD of the cooling fan 52 is horizontal, and an exhaust air chamber 10b for introducing cooling air from the cooling fan 52 is provided in the soundproof box 10, and among the side walls of the soundproof box 10 defining the exhaust air chamber 10b, a blowing outlet 31 that opens upward is provided within a range of a predetermined height from the upper end of the side wall (rear panel 12b) forward in the blowing direction BD of the cooling fan 52, and an exhaust air duct 30 is provided to extend the exhaust air chamber 10b in the blowing direction BD of the cooling fan 52, forming a flow path 14 for the cooling air from the cooling fan 52 to the blowing outlet 31 of the exhaust air duct 30,
The resistor 20 may be accommodated in the exhaust duct 30 so that the plane 21a of each resistance element 21 forms a vertical plane parallel to the blowing direction BD of the cooling fan 52 (claim 3: see Figures 3 and 4).

By using the configuration of the present invention described above, the engine-driven generator 1 of the present invention can achieve the following remarkable effects:

The resistor 20 is formed as an assembly of multiple flat resistance elements 21 arranged in parallel planes at a predetermined interval, and the resistors 20 are arranged in the flow path 14 of the cooling air generated by the cooling fan 52 so that the plane 21a of each resistance element 21 is parallel to the flow path 14 of the cooling air generated by the cooling fan 52. This makes it possible to suppress a decrease in the flow rate of the cooling air passing through the flow path 14 of the cooling air without the resistors 20 interfering with the flow of the cooling air.

As a result, the resistor 20 can be placed in the cooling air flow path 14 to provide optimal cooling while suppressing deterioration of the heat balance performance of the engine-driven generator 1.

In addition, by making each resistive element 21 that constitutes the resistor 20 flat, the surface area of the resistive element 21 can be increased, and the cooling efficiency of the resistor 20 itself can also be improved.

In a configuration in which the aforementioned cooling air flow path 14 in which such a resistor 20 is arranged is formed from the cooling fan 52 through the exhaust chamber 10b to the exhaust port 13 provided on the top plate (top panel 12d) of the soundproof box 10, the cooling air flow path 14 changes direction from horizontal to vertical in the exhaust chamber 10b as shown by the dashed arrow in Figure 1, causing turbulence and making it difficult for the cooling air to escape.

However, in a configuration in which the resistor 20 is accommodated below the exhaust port 13 so that the plane 21a of each resistor element 21 of the resistor 20 forms a vertical plane parallel to the blowing direction BD of the cooling fan 52, the resistor 20 functions as a straightening plate, and compared to a configuration in which the resistor 20 is not provided in the exhaust chamber 10b, the amount of cooling air (exhaust air) discharged outside the machine through the exhaust port 13 can be increased when the resistor 20 is provided, thereby improving the heat balance performance of the engine-driven generator 1.

Furthermore, among the side walls of the soundproof box 10 that define the exhaust air chamber 10b, an exhaust air duct 30 is provided within a range of a predetermined height from the upper end of the side wall (rear panel 12b) forward in the blowing direction BD of the cooling fan 52, and in a configuration in which the resistor 20 is housed within this exhaust air duct 30, even a large resistor 20 that cannot be housed within the exhaust air chamber 10b can be installed while suppressing a decrease in the exhaust air volume.

In particular, by adopting a configuration in which an exhaust duct 30 is provided in addition to a configuration in which an exhaust port 13 is provided on the top plate of the exhaust chamber 10b, it is possible to significantly increase the amount of cooling air (exhaust air volume) discharged outside the machine compared to a configuration in which such an exhaust duct 30 and resistor 20 are not provided.

Moreover, by preparing the exhaust duct 30 with the resistor 20 attached in advance, it becomes easier to assemble the resistor 20 to the engine-driven generator 1, and for example, the exhaust duct 30 equipped with the resistor 20 can be easily retrofitted to the engine-driven generator 1 as an optional item, etc.

Furthermore, in the configuration of the present invention, as described above, the exhaust duct 30 is provided so as to extend the exhaust chamber 10b in the blowing direction BD of the cooling fan 52 (rear of the soundproof box 10), so the overall height of the engine-driven generator 1 can be kept low compared to the conventional engine-driven generator 100 described with reference to Figure 6, which has an exhaust duct 130 that protrudes upward.

As a result, when the engine-driven generator 1 is loaded onto the bed of a truck for transport, for example, when traveling through places with height restrictions such as tunnels or under bridges, it is possible to prevent the exhaust duct 30 from being hit and damaged.

FIG. 2 is a side view of the engine-driven generator of the present invention. 1 is a perspective view of a main portion of an engine-driven generator according to the present invention; FIG. 11 is a side view showing a modified example of the engine-driven generator of the present invention. FIG. 4 is a perspective view of a main portion showing a modified example of the engine-driven generator of the present invention. FIG. 1A is a front view of a resistor for increasing exhaust gas temperature (conventional), and FIG. FIG. 1 is a side view of a main portion of a conventional engine-driven generator.

The engine-driven generator of the present invention will be described below with reference to the attached drawings.

The reference numeral 1 in FIG. 1 denotes an engine-driven generator of the present invention, which is configured as a packaged engine-driven generator 1, with the components housed in a soundproof box 10 made up of a base 11 and a soundproof case 12.

The aforementioned base 11 constituting the soundproof box 10 is used to mount the components of the engine-driven generator 1, and other components such as the engine (water-cooled diesel engine) 50 and the generator body 70 driven by the engine 50 are mounted on this base 11.

The aforementioned soundproof case 12, which covers the base 11 on which the components of the engine-driven generator 1 are placed, is box-shaped and made up of side walls consisting of a front panel 12a, a rear panel 12b, and a side panel 12c, and a top panel 12d that forms a top plate that covers the upper part of the space enclosed by these side walls. By covering the base 11 with this soundproof case 12, the engine-driven generator 1 is packaged as described above.

The space inside the soundproof box 10 is divided into two compartments, an engine compartment 10a and an exhaust compartment 10b, by a vertically erected partition wall 15. The engine compartment 10a houses the engine 50, a radiator 51 mounted on the engine 50, a cooling fan 52 that blows cooling air onto the radiator 51, and a generator body 70 driven by the engine 50.

On the other hand, the other chamber separated by the partition wall 15, the exhaust air chamber 10b, contains an exhaust gas aftertreatment device 82 installed in the exhaust passage of the engine, as well as a resistor 20 that is connected to the generator body 70 when increasing the temperature of the exhaust gas introduced into the exhaust gas aftertreatment device 82 for the aforementioned activation of the DOC, regeneration of the DPF, cleaning of the SCR catalyst, etc.

A communication port 16 that connects the engine compartment 10a and the exhaust compartment 10b is formed in the center of the aforementioned partition wall 15 that divides the soundproof box 10 into two compartments (see Figure 2), and the aforementioned radiator 51 housed in the engine compartment 10a is positioned opposite this communication port 16 (see Figure 1).

The cooling fan 52 of the engine 50 is installed in the engine compartment 10a so that it can blow cooling air horizontally with its blowing direction BD toward the radiator 51 and the communication port 16.

When the cooling fan 52 rotates, air from outside the engine compartment 10a is introduced into the engine compartment 10a through the intake port 17 (see Figure 1) provided on the side wall of the soundproof box 10 at the position where the engine compartment 10a is formed, and the cooling fan 52 blows out the introduced air in the blowing direction BD as cooling air.

The cooling air from the cooling fan 52 exchanges heat with the cooling water in the radiator 51 as it passes through the radiator 51 located in front of the air outlet direction BD, then reaches the exhaust chamber 10b through the communication port 16 in the partition wall 15, where it changes direction to a vertical direction and is exhausted outside the soundproof box 10 through the exhaust port 13 on the top plate of the exhaust chamber 10b.

Therefore, inside the soundproof box 10 of the engine-driven generator 1, a flow path 14 for the cooling air generated by the cooling fan 52 is formed, which runs from the cooling fan 52 to the exhaust port 13, and the resistor 20 is disposed in this cooling air flow path 14.

As shown in FIG. 2, this resistor 20 is formed as an assembly of multiple flat plate-shaped resistive elements 21 arranged in parallel with a predetermined distance between them.

The individual resistive elements 21 that make up this resistor 20 are not particularly limited in structure as long as they are formed in a flat plate shape, and various structures can be used.

The resistance element 21 can be formed using a high resistance material such as a known metal heating element such as Ni-Cr, Fe-Cr-Al, or Fe-Cr-Al-Co, or a non-metallic heating element such as silicon carbide, and such a metallic or non-metallic resistance material may be directly molded into a plate to form the resistance element 21.

The resistive element 21 may also be a multi-layer structure in which a metallic or non-metallic resistive material is supported by laminating, sandwiching, encapsulating, or the like on an insulating heat sink or the like.

Furthermore, the resistive element 21 may have a structure formed by winding a resistive wire around the outer periphery of a plate-shaped insulator.

As shown in FIG. 2, the required number of such plate-like resistance elements 21 are attached to a holding frame 22 or the like in a plane parallel manner at a specified interval, and each resistance element 21 is connected to each other, so that the assembly of these resistance elements 21 forms a resistor 20 having a specified resistance value required to obtain a desired increase in exhaust temperature.

The resistor 20 thus configured is placed in the cooling air flow path 14 so that the plane 21a of each resistor element 21 is parallel to the cooling air flow path 14.

In this way, by arranging the resistors 20 so that the planes 21a of each resistance element 21 are parallel to the cooling air flow path 14, it is possible to minimize the flow resistance applied to the cooling air flowing through the cooling air flow path 14, and even though the resistors 20 are arranged in the cooling air flow path 14, it is possible to suppress a decrease in the heat balance performance of the engine-driven generator 1.

As shown in Figures 1 and 2, in a configuration example in which the top panel 12d of the soundproof box 10 is provided with an exhaust port 13 that communicates with the exhaust chamber 10b, the resistors 20 described above are attached below the exhaust port 13 described above so that the plane 21a of each resistor element 21 forms a vertical plane parallel to the blowing direction BD of the cooling fan 52, and in the illustrated example, a plane parallel to the longitudinal side wall (side panel 12c) of the soundproof box 10.

By configuring it in this way, even if the cooling air flow path 14 is formed so that the cooling air blown out horizontally by the cooling fan 52 changes direction to a vertical direction within the exhaust chamber 10b as shown by the dashed arrow in Figure 1, the plane 21a of the resistance element 21 can always be oriented parallel to the flow of the cooling air.

In addition, it has been confirmed that the configuration shown in Figures 1 and 2 can increase the flow rate (exhaust air volume) of cooling air exhausted outside the machine through the exhaust port 13, compared to a configuration in which the resistor 20 is not placed in the exhaust chamber 10b.

The following Table 1 shows the change in exhaust air volume (actual measured value) and the change in allowable operating temperature depending on whether or not a resistor 20 is placed in the exhaust air chamber 10b in the example configuration of the engine-driven generator 1 shown in Figures 1 and 2.

Here, the "allowable operating temperature" refers to the upper limit of the ambient temperature at which the engine-driven generator 1 can be operated, and was calculated according to the following formula based on the actual measured values of the "engine cooling water temperature" and the "engine oil temperature" measured when the resistor 20 was installed and when it was not installed.
Allowable operating temperature = Allowable outside operating temperature (40°C) + Minimum allowable value

Here, the "minimum allowable value" is the smaller of either the value obtained by subtracting the "actual measured value of engine coolant temperature" from the "required specification value of engine coolant temperature" or the value obtained by subtracting the "actual measured value of engine oil temperature" from the "required specification value of engine oil temperature."

In addition, the "Effect" in Table 1 shows the percentage of the exhaust air volume and the allowable operating temperature when the resistor 20 is installed, when the exhaust air volume and the allowable operating temperature when the resistor 20 is not installed are both set at 100%.

It has been confirmed that in the configuration of the engine-driven generator 1 of the present invention in which a resistor 20 is provided in the exhaust chamber 10b as shown in Figures 1 and 2, an increase in exhaust volume of 26.7 ^m3 per minute (445 liters per second) can be achieved compared to a case in which the resistor 20 is not provided.

This significant increase in exhaust air volume is believed to be the result of the resistor 20 structure, in which multiple flat resistance elements 21 are arranged parallel to each other at a specified distance, functioning as a straightening plate to straighten the flow of cooling air.

In other words, it is believed that the resistor 20 functioned as a straightening plate, and thus the occurrence of turbulence was suppressed and the cooling air was discharged smoothly, even when the cooling air flow path 14 was formed so that the cooling air changed direction from horizontal to vertical within the exhaust chamber 10b as described above.

By increasing the amount of exhaust air in this way, the inside of the soundproof box 10 is cooled appropriately, and the allowable operating temperature of the engine-driven generator 1 is improved by 5.2°C (13%) compared to when the resistor 20 is not provided.

As mentioned above, by making the resistive element 21 flat, the surface area of the resistive element 21 is increased, which allows the resistive element 21 itself to have good heat dissipation properties, and the resistor 20 itself can be cooled appropriately.

Thus, in the configuration of the engine-driven generator 1 of the present invention, the resistor 20 connected to the generator body 70 when increasing the exhaust temperature of the engine is arranged in the cooling air flow path 14 (exhaust air chamber 10b), but it is possible to prevent a decrease in the amount of cooling air (exhaust air volume) discharged outside the machine. In particular, in the configuration of the embodiment shown in Figures 1 and 2, it is possible to increase the amount of exhaust air, and while maintaining or improving the heat balance performance of the engine-driven generator 1, the resistor 20 itself can also be cooled appropriately.

As described above, in the engine-driven generator 1 described with reference to Figures 1 and 2, the resistor 20 connected to the generator body 70 when increasing the exhaust temperature of the engine is housed in the exhaust chamber 10b of the soundproof box 10.

In contrast, in the engine-driven generator 1 shown in Figures 3 and 4, a certain height range is removed from the upper end of the rear panel 12b, which is the side wall of the soundproof box 10 that defines the exhaust chamber 10b, in front of the blowing direction BD of the cooling fan 52, and an exhaust duct 30 with an upwardly opening air outlet 31 is attached to this portion to extend the exhaust chamber 10b to the rear of the soundproof box 10.

Therefore, in this configuration, the cooling air generated by the cooling fan 52 is not only exhausted outside the machine through the exhaust port 13 provided on the top plate of the exhaust chamber 10b, but also through the outlet 31 of the exhaust duct 30, expanding the flow path 14 of the cooling air as shown by the dashed arrow in Figure 3.

Then, within this exhaust duct 30, a resistor 20 having a structure similar to that described with reference to FIG. 2 is housed so that the plane 21a of each resistance element 21 of the resistor 20 is a vertical plane parallel to the blowing direction BD of the cooling fan 52, which in the illustrated configuration is a plane parallel to the side panel 12c of the soundproof box 10. With this configuration, the plane 21a of the resistance element 21 of the resistor 20 is arranged so as to be parallel to the flow of cooling air flowing within the exhaust duct 30.

In this way, in the engine-driven generator 1 described with reference to Figures 3 and 4, the resistor 20 is housed in the exhaust duct 30, and the flow path 14 for the cooling air is expanded by the amount of the exhaust duct 30.

In addition, the resistor 20 exerts a straightening effect on the cooling air flowing through the exhaust duct 30, allowing the cooling air passing through the exhaust duct 30 to be discharged smoothly.

As a result, even in the configuration of the engine-driven generator 1 shown in Figures 3 and 4, even though a resistor 20 is provided in the cooling air flow path 14, the exhaust air volume can be increased rather than decreased, and the heat balance performance of the engine-driven generator 1 can be maintained or improved.

In addition, by making the resistive element 21 of the resistor 20 flat, the resistor 20 itself can be cooled appropriately, similar to the engine-driven generator 1 described with reference to Figures 1 and 2.

Furthermore, in the engine-driven generator 1 shown in Figures 3 and 4, the resistor 20 is provided in the exhaust duct 30 attached to the soundproof box 10, so that even a large resistor 20 that cannot be accommodated in the exhaust chamber 10b can be mounted on the engine-driven generator 1.

In addition, by having the resistor 20 housed in the exhaust duct 30 attached to the soundproof box 10, the resistor 20 can be easily attached to the engine-driven generator 1 by preparing the exhaust duct 30 with the resistor 20 attached in advance, and it can also be easily handled in cases where the resistor 20 is attached as an option.

Moreover, by providing the aforementioned exhaust duct 30 in a direction that extends rearward from the soundproof box 10, the overall height of the engine-driven generator 1 can be maintained without increasing, even though the exhaust duct 30 is provided.

As a result, when the engine-driven generator 1 of this embodiment is mounted on the bed of a truck or the like and passes through places with height restrictions, such as under bridges or tunnels, it is possible to prevent the exhaust duct 30 from being hit and damaged.

REFERENCE SIGNS LIST 1 Engine-driven generator 10 Soundproof box 10a Engine compartment 10b Exhaust chamber 11 Base 12 Soundproof case 12a Front panel 12b Rear panel 12c Side panel 12d Top panel 13 Exhaust port 14 Cooling air flow path 15 Partition wall 16 Communication port 17 Intake port 20 Resistor 21 Resistance element 21a Flat surface 22 Holding frame 30 Exhaust duct 31 Air outlet 50 Engine 51 Radiator 52 Cooling fan 70 Generator body 82 Exhaust gas aftertreatment device 100 Engine-driven generator 110 Soundproof box 112d Top panel 113 Exhaust port 114 Cooling air flow path 120 Resistor 121 Resistance element 121a Core material 121b Resistance wire 122 Frame 130 Exhaust duct 150 Engine 151 Radiator 152 Cooling fan P Parallel mounting surface

Claims (3)

An engine-driven generator including a diesel engine, a generator body driven by the engine, an exhaust gas aftertreatment device provided in an exhaust passage of the engine, and a resistor connected to the generator body when increasing the temperature of exhaust gas introduced into the exhaust gas aftertreatment device,
The resistor is formed as an assembly of a plurality of flat plate-shaped resistive elements arranged in parallel at a predetermined interval,
An engine-driven generator characterized in that the resistors are arranged in the flow path of the cooling air so that the plane of each resistance element always forms a vertical plane parallel to the flow path of the cooling air generated by the cooling fan and exerts a rectifying effect on the cooling air which changes direction from horizontal to vertical . The cooling fan is disposed in a soundproof box so that the blowing direction of the cooling fan is horizontal, and an exhaust chamber is provided in the soundproof box to introduce cooling air from the cooling fan and communicate with the outside of the machine via an exhaust port provided in the top plate of the soundproof box, forming a flow path of the cooling air from the cooling fan to the exhaust port, and
2. The engine-driven generator according to claim 1, wherein the resistors are accommodated below the exhaust port such that the planes of the resistor elements form a vertical plane parallel to the blowing direction of the cooling fan. The cooling fan is disposed in a soundproof box so that the blowing direction of the cooling fan is horizontal, and an exhaust chamber for introducing cooling air from the cooling fan is provided in the soundproof box, and a side wall of the soundproof box defining the exhaust chamber has an air outlet opening upward within a range of a predetermined height from the upper end of the side wall forward in the blowing direction of the cooling fan, and an exhaust duct is provided to extend the exhaust chamber in the blowing direction of the cooling fan, forming a flow path for the cooling air from the cooling fan to the air outlet of the exhaust duct,
2. The engine-driven generator according to claim 1, wherein the resistors are accommodated in the exhaust duct such that a plane of each of the resistor elements forms a vertical plane parallel to the blowing direction of the cooling fan.

Images