JP2010133348A - Nox reduction device of internal combustion engine and nox reducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the volume of NOx from an internal combustion engine with a simple structure and at low cost. <P>SOLUTION: An NOx reduction device is provided with a water heater 5 which generates heated water by the exhaust of an engine 1, a humidifier 4 which generates highly humid air by the heated water generated by the water heater 5, and an intake fan 7 which supplies highly humid air generated by the humidifier 4 to the intake side of the engine 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a NOx reduction device and a NOx reduction method for an internal combustion engine that reduce the amount of NOx (nitrogen oxide) in exhaust gas from the internal combustion engine.

Conventionally, a technique for reducing the amount of NOx from an internal combustion engine by mixing highly humid air (humidified air) with intake air and supplying (supplying) the internal combustion engine is known (for example, Patent Documents 1 and 2). reference.). This technique reduces the amount of NOx in exhaust gas by increasing the humidity of air introduced into the cylinder and lowering the maximum combustion temperature during fuel combustion. In such a technique, high-humidity air is generated by a humidifier independent from the internal combustion engine. That is, a humidifier using external heat or ultrasonic waves, or a humidifier using a cooling tower equipped with a fan is separately installed, and the humidifier generates high-humidity air and supplies it to the internal combustion engine. It is.
JP 2006-029309 A JP 2002-048010 A

  By the way, in the conventional humidifier as described above, an energy source is required to generate heat, ultrasonic waves, or to rotate the fan. As a result, there is a problem that the facilities are large and the cost is high.

  Accordingly, an object of the present invention is to provide an internal combustion engine NOx reduction device and an NOx reduction method capable of reducing the amount of NOx from the internal combustion engine with a simple configuration and at a low cost.

  In order to achieve the above object, the invention described in claim 1 includes warm water generating means for generating warm water with exhaust gas from an internal combustion engine, humidifying means for generating humid air with warm water generated by the warm water generating means, A NOx reduction device for an internal combustion engine, comprising: supply means for supplying humidified air generated by the humidifying means to an intake side of the internal combustion engine.

  According to the present invention, warm water is generated by the warm water generating means using the exhaust gas from the internal combustion engine, subsequently humidified air is generated using the warm water by the humidifying means, and the humidified air is supplied to the internal combustion engine by the supplying means. Supplied to the intake side. Thereby, the amount of NOx discharged from the internal combustion engine is reduced.

  According to a second aspect of the present invention, in the NOx reduction device for an internal combustion engine according to the first aspect, the humidifying means generates first humidified air by heating the water in the water tank with the hot water. And second humidifying means for generating humid air by scattering the hot water into the atmosphere, and generation of humid air by at least one of the first humidifying means and the second humidifying means is selectable. It is characterized by that.

  Invention of Claim 3 produces | generates warm water with the waste gas from an internal combustion engine, produces | generates humidified air with the produced | generated warm water, and supplies the produced | generated humidified air to the intake side of the said internal combustion engine, This is a NOx reduction method for an internal combustion engine.

  According to the first and third aspects of the present invention, warm water is generated using exhaust heat of exhaust gas from the internal combustion engine, and humidified air is generated with the warm water. Therefore, an energy source for generating humidified air is provided. It becomes unnecessary separately. As a result, facilities can be simplified (with a simple configuration), energy can be saved, and costs can be reduced.

  According to the second aspect of the present invention, since the second humidifying means generates humidified air by scattering hot water into the atmosphere, it is possible to immediately generate a large amount of humidified air. In the means, since the humidified air is generated by heating the water in the water tank with warm water, the generation speed is slower than the second humidifying means (the amount of generation is small). Since generation of humidified air by at least one of the first humidifying means and the second humidifying means is freely selectable, appropriate (appropriate amount) of humidified air is supplied based on the operating state of the internal combustion engine, the outside air condition, and the like. It becomes possible to supply.

  The present invention will be described below based on the illustrated embodiments.

  FIG. 1 is a diagram showing equipment around an engine (internal combustion engine) 1 including an internal combustion engine NOx reduction device (hereinafter referred to as “NOx reduction device”) according to an embodiment of the present invention.

  In this embodiment, the engine 1 and the generator 2 are installed in the first level, the exhaust gas silencer 3 and the like are installed in the second level, and the humidifier (humidifying means) 4 and the like are installed in the underground level. The engine 1 and the generator 2 are connected, and the exhaust gas from the engine 1 is sent to the exhaust gas silencer 3 through the exhaust gas pipe 6 and exhausted from the chimney 12.

  A water heater (hot water generating means) 5 is disposed between the engine 1 and the exhaust gas silencer 3. The water heater 5 is a heat exchanger that generates hot water from the exhaust gas from the engine 1, and the exhaust gas discharged from the engine 1 and the return water from the humidifier 4 flow in. And by exchanging heat between the high-temperature exhaust gas and the low-temperature return water, the return water is heated to generate hot water. The humidifier 4 generates high-humidity air (humidified air) with the hot water generated by the water heater 5, and the water heater 5 and the humidifier 4 are connected via a hot water pipe 51 and a return water pipe 52. ing.

  That is, as shown in FIG. 2, the downstream end portion of the hot water pipe 51 is connected to the first humidifying pipe 41 of the humidifier 4, and the first humidifying pipe 41 passes through the water tank 46 and passes through the three-way valve 47. Are connected to the second humidifying tube 42 and the third humidifying tube 43. Here, the water tank 46 is a container having a large opening on the upper surface so that high-humidity air, which will be described later, is easily generated, that is, the water in the water tank 46 is easily evaporated and released into the atmosphere. The downstream ends of the second humidifying pipe 42 and the third humidifying pipe 43 are connected to a fourth humidifying pipe 44, and the downstream end of the fourth humidifying pipe 44 is connected to the return water pipe 52. The third humidifying pipe 43 has a horizontal portion 43a extending horizontally above the water tank 46, and a plurality of water flow holes 43b are formed in the horizontal portion 43a, and hot water is supplied to the water tank 46 side from the water flow holes 43b. It flows in the shape of a shower (scatters) toward the atmosphere.

  Further, a submersible pump 48 is disposed in the water tank 46, and a fifth humidifying tube 45 is connected to the discharge port of the submersible pump 48. The fifth humidifying pipe 45 extends above the water tank 46, has a downstream end connected to the return water pipe 52 side, and operates the submersible pump 48 so that water in the water tank 46 flows to the return water pipe 52 side. It is like that.

  Then, when the hot water from the water heater 5 is supplied to the first humidifying pipe 41 via the hot water pipe 51, the water in the water tank 46 is heated and evaporated by the hot water flowing through the first humidifying pipe 41, resulting in high humidity. Air is generated (outside air is humidified). Subsequently, when the three-way valve 47 is open to the second humidifying pipe 42 side, the warm water in the first humidifying pipe 41 flows into the return water pipe 52 via the second humidifying pipe 42 and returns. It is refluxed to the water heater 5 as water. On the other hand, when the three-way valve 47 is open to the third humidifying pipe 43 side, the hot water in the first humidifying pipe 41 flows into the third humidifying pipe 43 and flows out from the water flow hole 43b in a shower shape. Thus, highly humid air is generated.

  Thus, the 1st humidification pipe | tube 41 and the water in the water tank 46 comprise the 1st humidification means which produces | generates highly humid air by heating the water in a water tank with warm water, and the 3rd humidification pipe | tube is comprised. By 43, the 2nd humidification means which produces | generates highly humid air by scattering warm water to air | atmosphere is comprised. And since the 2nd humidification means produces | generates highly humid air by scattering warm water to air | atmosphere, it is possible to produce | generate a large amount of highly humid air immediately, and in the 1st humidification means, the water tank 46 with warm water. Since the water inside is heated to generate highly humid air, the generation rate is slower than the second humidifying means (the amount of generation is small).

  Also, by switching the opening direction of the three-way valve 47, it is possible to generate high-humidity air only by the first humidification means, or to generate high-humidity air by the first humidification means and the second humidification means. Can be selected. Here, switching of the three-way valve 47, that is, whether hot water is recirculated via the second humidifying pipe 42 (whether it is not necessary to generate a large amount of high-humidity air) or recirculated via the third humidifying pipe 43 Whether it is necessary to generate a large amount of high-humidity air is set based on the operating state of the engine 1 and the outside air state. For example, when the outside air is dry or when rapid humidification is required, more highly humid air can be quickly generated via the third humidification pipe 43, or the second humidification pipe can be used when the engine 1 is at rest. 42 to go to a standby state. Alternatively, the amount of NOx in the exhaust gas from the engine 1 is measured, and the opening direction is switched based on the measurement result. Such switching may be performed manually or automatically.

  On the other hand, when the water in the water tank 46 reaches a certain amount or more, the submersible pump 48 is operated, and the water in the water tank 46 is returned to the water heater 5 through the return water pipe 52 as described above. .

  An intake fan (supply means) 7 for supplying highly humid air generated by the humidifier 4 to the intake pipe 11 (intake side) of the engine 1 is installed in front of the humidifier 4 (on the engine 1 side). Yes. A filter 8 is installed between the intake fan 7 and the humidifier 4. When the intake fan 7 is operated, the highly humid air generated by the humidifier 4 is sent to the engine 1 side through the filter 8 together with the intake air (outside air), and is supplied to the engine 1 through the intake pipe 11. It has come to be.

  The water heater 5 (including the hot water pipe 51 and the return water pipe 52), the humidifier 4 and the intake fan 7 as described above constitute a NOx reduction device.

  Next, the NOx reduction method of the engine 1 by the NOx reduction device having such a configuration will be described.

  First, when the engine 1 is operated, the exhaust gas discharged from the engine 1 is sent to the water heater 5, and hot water is generated by the water heater 5 as described above. Next, this hot water is supplied to the humidifier 4 through the hot water pipe 51. Subsequently, as described above, the water in the water tank 46 is heated to generate high-humidity air, and when the three-way valve 47 is open to the third humidifying tube 43 side, Hot water flows out from the water flow holes 43b in the form of a shower to generate highly humid air. Then, the generated highly humid air is sent to the intake pipe 11 together with the outside air by the intake fan 7 and supplied to the engine 1. As a result, the humidity of the air in the cylinder of the engine 1 increases, the maximum combustion temperature during fuel combustion decreases, and the amount of NOx in the exhaust gas decreases. On the other hand, the hot water that has passed through the water tank 46 and has fallen in temperature passes through the second humidifying pipe 42 or the third humidifying pipe 43, and returns as the return water through the fourth humidifying pipe 44 and the return water pipe 52. It is refluxed to the water heater 5. And this return water becomes warm water again by the water heater 5, and repeats such a cycle.

  As described above, according to the NOx reduction device and the NOx reduction method, hot water is generated using the exhaust heat of the exhaust gas from the engine 1, and highly humid air is generated with this hot water. ), It is possible to simplify the equipment, save energy, and reduce costs. In addition, maintainability increases with the simplification of the equipment, and the humidifier 4 is installed away from the engine 1, so that the humidification state can be easily confirmed.

  Further, the humidifier 4 is provided with a second humidifying means capable of instantly generating a large amount of high-humidity air in addition to the first humidifying means with which the generation rate of the high-humidity air is relatively slow. As the selection means, it is possible to select whether the generation is performed only by the first humidification means or both. For this reason, it is possible to supply appropriate (appropriate amount) of highly humid air based on the operating state of the engine 1 and the outside air state.

  Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if there is a design change or the like without departing from the gist of the present invention, Included in the invention. For example, in the above embodiment, it is possible to select whether to generate highly humid air only by the first humidifying means or to generate highly humid air by the first humidifying means and the second humidifying means. However, the generation of highly humid air by only one of the first humidifying means and the second humidifying means may be selected. Further, although the intake fan 7 is the supply means, a pipe or the like that guides highly humid air to the intake side of the internal combustion engine may be used as the supply means.

It is a figure which shows the installation around the engine including the NOx reduction apparatus which concerns on embodiment of this invention. It is a perspective view which shows the humidifier of the NOx reduction apparatus of FIG.

Explanation of symbols

1 engine (internal combustion engine)
2 Generator 3 Exhaust gas silencer 4 Humidifier (humidification means)
41 1st humidification pipe 43 3rd humidification pipe 43b Water flow hole 46 Water tank 47 Three-way valve 48 Submersible pump 5 Water heater (warm water production | generation means)
51 Hot water pipe 52 Return water pipe 7 Intake fan (supply means)

Claims (3)

  Hot water generating means for generating hot water with exhaust gas from the internal combustion engine, humidifying means for generating humid air with the hot water generated by the hot water generating means, and humidified air generated by the humidifying means for the intake side of the internal combustion engine A NOx reduction device for an internal combustion engine, comprising:   The humidifying means includes a first humidifying means for generating humid air by heating water in the water tank with the hot water, and a second humidifying means for generating humid air by scattering the warm water to the atmosphere. 2. The NOx reduction device for an internal combustion engine according to claim 1, wherein generation of humidified air by at least one of the first humidifying means and the second humidifying means is selectable.   A method for reducing NOx of an internal combustion engine, comprising: generating hot water with exhaust gas from the internal combustion engine; generating humidified air with the generated hot water; and supplying the generated humidified air to the intake side of the internal combustion engine.

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