JP2006105014A - Exhaust emission control device utilizing reducing agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device utilizing a reducing agent, keeping the temperature of a liquid reducing agent at a normal freezing temperature or more so as to avoid freezing of the liquid reducing agent by a small-sized compact device without requiring special consumption energy even in operation that the temperature of the liquid reducing agent is lowered such as operation of an engine at a low temperature in a cold district. <P>SOLUTION: This exhaust emission control device utilizing the liquid reducing agent, provided with an engine cooling system introducing high temperature cooling water after cooling the engine to a surge tank and feeding cooling water with air separated into a water pump by the surge tank and an exhaust emission control system supplying the liquid reducing agent stored in a reducing agent tank into a reduction catalyst converter, is designed that the surge tank is arranged in the reducing agent tank so as to directly heat-exchange the liquid reducing agent in the reducing agent tank with the surge tank, and the liquid reducing agent is heated by the heat of the surge tank. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention is applied to a vehicle engine, a stationary engine for industrial use or power generation, and the like, and engine cooling configured to separate air in cooling water in a surge tank into which high-temperature cooling water from the engine is introduced. The present invention relates to a reducing agent-utilizing exhaust gas purification apparatus including an exhaust gas purification system that includes a system and supplies a liquid reducing agent accommodated in a reducing agent tank into a reduction catalytic converter.

In an exhaust gas purification converter using a NOx reduction catalyst, a technique for promoting a reduction reaction by the reduction catalyst by injecting a liquid reducing agent such as urea water (urea water) on the upstream side of the reduction catalyst of the exhaust gas purification converter is provided. Yes.
As such a technique, the technique of patent document 1 (Unexamined-Japanese-Patent No. 2000-27627) and patent document 2 (patent 3238416) is provided.

In the technique of Patent Document 1 (Japanese Patent Laid-Open No. 2000-27627), a liquid reductant for promoting a reduction reaction of a reduction catalyst of an exhaust gas purification converter installed in an exhaust passage of an internal combustion engine is used as a heating wire for exhaust gas purification. The heating wire is disposed and covered with a heat insulating material, and the heating wire is also provided in the reducing agent tank, and the heating wire is energized or interrupted according to the outside air temperature or the reducing agent temperature, and the temperature of the liquid reducing agent Is kept in the temperature range necessary to avoid freezing of the liquid reducing agent, thereby preventing the reduction of the reduction reaction due to freezing of the liquid reducing agent.
Moreover, in the technique of patent document 2 (patent 3238416 gazette), the liquid reducing agent for accelerating | stimulating the reduction reaction of the reduction catalyst of an exhaust gas purification converter is accommodated in the fuel accommodating part (fuel tank) which accommodates fuel. The reducing agent container is provided with a wall having good heat conductivity, and the reducing agent container is surrounded by fuel to prevent the liquid reducing agent from freezing.

JP 2000-27627 A Japanese Patent No. 3238416

  In the technique of Patent Document 1 (Japanese Patent Laid-Open No. 2000-27627) provided as means for preventing freezing of the liquid reducing agent for promoting the reduction reaction of the reduction catalyst of the exhaust gas purification converter as described above. If the temperature of the liquid reductant is reduced when the temperature of the liquid reductant decreases during operation at low temperatures in a cold region of the engine, the temperature of the liquid reductant is higher than the freezing temperature. Therefore, it is necessary to increase the amount of heat heated by the heating wire, so that the operating energy (operating power) of the heating wire heating device increases and the size of the device increases.

Further, in the technique of Patent Document 2 (Japanese Patent No. 3238416), the temperature of the fuel for heating the reducing agent storage section in which the liquid reducing agent is stored is relatively low. When the temperature of the liquid reducing agent decreases during low-temperature operation, the amount of heat of heating of the liquid reducing agent is insufficient, and it becomes difficult to raise the temperature of the liquid reducing agent above the freezing temperature. Freezing is inevitable.
And so on.

  In view of the problems of the prior art, the present invention is a compact and compact device that does not require special energy consumption even during operation in which the temperature of the liquid reducing agent is lowered, such as during low-temperature operation in a cold region of an engine. Accordingly, it is an object of the present invention to provide a reducing agent-utilizing exhaust gas purification apparatus that can keep the liquid reducing agent temperature at or above the freezing temperature and avoid the freezing of the liquid reducing agent.

  The present invention achieves such an object, and includes an engine cooling system in which high-temperature cooling water after engine cooling is introduced into a surge tank, and cooling water separated from air in the surge tank is sent to a water pump. The reductant-utilizing exhaust gas purification apparatus having an exhaust gas purification system configured to supply the liquid reductant contained in the reductant tank into the reduction catalytic converter, wherein the surge tank is placed in the reductant tank. The liquid reducing agent in the tank and the surge tank are installed so that heat can be directly exchanged, and the liquid reducing agent is heated by the heat of the surge tank.

  In recent years, means using urea water (urea water) as a liquid reducing agent for promoting a reduction reaction of a reduction catalyst of an exhaust gas purification converter has come to be used. The urea water does not freeze until the freezing temperature is as low as about −11 ° C., so it is a suitable material as a liquid reducing agent. However, during operation at a very low temperature in a cold region, the temperature of the liquid reducing agent is urea water. In such a case, freezing cannot be avoided even if the urea water is used as the liquid reducing agent.

  Therefore, according to the invention, when the engine is operated, the surge tank in which the engine cooling water on the engine outlet side, which is constantly kept at a high temperature of about 50 to 60 ° C. or more without being greatly affected by the atmospheric temperature, is accommodated, Preferably, the liquid reductant in the reductant tank is directly heated with the high-temperature engine cooling water as described above by immersing in the reductant tank and directly exchanging heat between the surge tank and the liquid reductant. It is possible to heat the liquid reductant in the reductant tank with heat released from the heat transfer surface with a large heat transfer area composed of the entire outer surface of the surge tank, and the heating source consisting of engine coolant is high Become.

In addition, since the liquid reducing agent in the reducing agent tank is directly heated using the heat of the high-temperature engine cooling water, each of the different liquid reducing agents such as Patent Document 1 (Japanese Patent Laid-Open No. 2000-27627) can be used. No heating device is required, and energy efficiency is improved without requiring special energy consumption.
Furthermore, since the surge tank is immersed in the reducing agent tank and heat is directly exchanged between the surge tank and the liquid reducing agent, the structure of the liquid reducing agent heating device is simplified and the inside of the reducing agent tank Since the surge tank is fully contained, the device becomes compact and compact.

In this invention, preferably, the surge tank is provided with a plurality of heat transfer fins on an outer surface facing the liquid reducing agent tank.
With this configuration, the heat transfer area between the surge tank and the liquid reducing agent is increased by providing a plurality of heat transfer fins on the outer surface of the surge tank, and the heating effect of the liquid reducing agent by the surge tank is improved. To do.

In the present invention, preferably, a heater for heating the liquid reducing agent is installed in a lower portion of the reducing agent tank.
As a specific configuration of the electric control circuit for controlling the heater current, the electric control circuit for controlling the heater current includes a first excitation coil that is excited by an ON operation of a key ignition switch for starting the engine, A first contact for energizing the heater with a current from the battery by the first excitation coil, and an open contact during the excitation operation of the first excitation coil and a closed contact during the non-excitation in conjunction with the first contact. A first heater circuit having a second contact, a first heater switch for energizing a current from a power source only during manual operation, a second excitation coil energized by energization of the first heater switch, and A normally-open third contact for energizing the heater with a current from a power source by excitation of the second excitation coil, and via the second contact when the second contact is closed from the downstream side of the third contact. Connected between the second excitation coil and the first heater switch to excite the second excitation coil, and a normally closed switch between the second contact and the second excitation coil And a second heater circuit having a second heater switch for stopping the excitation of the second exciting coil by shutting off the switch.
Further, in the electric control circuit, the second heater circuit has a pilot lamp that is turned on when the second heater circuit is operated in parallel with the second excitation coil on the downstream side of the second heater switch. It is good to install.

If the heater and the electric control circuit for controlling the current of the heater are provided in this way, when the liquid reducing agent is frozen during a long period of stoppage of the engine operation at night or the like during operation in a cold region, Freezing is released by heating the liquid reducing agent with a heater, and the liquid reducing agent can be supplied from the start of the engine.
In addition, even when the engine is operated in a cryogenic state where the liquid reducing agent is likely to freeze, freezing of the liquid reducing agent can be reliably avoided by using both the heating by the surge tank and the heating by the heater.

In this invention, preferably, a temperature sensor for detecting a temperature of the liquid reducing agent stored in the reducing agent tank, and a temperature detection value of the liquid reducing agent from the temperature sensor are input, and the temperature detection is performed. And a heater controller that operates the heater when the temperature of the liquid reducing agent is equal to or lower than a set allowable temperature based on the value.
With this configuration, when the temperature detection value of the liquid reducing agent from the temperature sensor exceeds the freezing temperature, the heater operation can be automatically stopped, so that the heater operation can be kept to the minimum necessary. The operating energy of the heater can be saved, and when the operating energy of the heater is covered by the engine, the fuel consumption rate of the engine can be reduced.

In this invention, it is preferable that a reducing agent amount meter that detects the amount of the liquid reducing agent stored in the reducing agent tank is provided, and the heater controller receives the reducing agent input from the reducing agent amount meter. The heater is configured to stop operating when the measured amount of storage becomes equal to or less than the set minimum storage.
With this configuration, the heater operation is automatically stopped when the measured amount of the reducing agent in the reducing agent amount meter is less than the minimum amount that does not require heating of the liquid reducing agent. The waste of operating energy can be eliminated.

In this invention, it is preferable that the heater controller is connected to a key ignition switch circuit of an engine and is configured to operate the heater when the key ignition switch is in an ON state.
If comprised in this way, useless operation of a heater at the time of an engine non-operation can be avoided by connecting operation of a heater with operation of an engine (when a key ignition switch is in an ON state).

  According to the present invention, since the liquid reducing agent in the reducing agent tank is directly heated by utilizing the heat of the high-temperature engine cooling water in the surge tank, there is no need for a separate liquid reducing agent heating device. Energy efficiency is improved without requiring a large amount of energy consumption, and the surge tank is immersed in the reducing agent tank so that the surge tank and the liquid reducing agent are directly heat-exchanged. The structure becomes simple and the device becomes small and compact.

  With such a small and compact device that improves energy efficiency without requiring special energy consumption and has a simple structure, even if urea water having a low freezing temperature is used as the liquid reducing agent, Even in an extremely low temperature operation state where freezing is not avoided, the temperature of the liquid reducing agent can be maintained at a temperature equal to or higher than the freezing temperature at all times. It can be supplied to the side to promote the reduction reaction by the reduction catalyst.

  Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this example are not intended to limit the scope of the present invention only to specific examples unless otherwise specified. Only.

FIG. 6 is an overall configuration diagram of an exhaust gas purification apparatus using a reducing agent for an engine to which the first embodiment of the present invention is applied.
In FIG. 6, 6 is a reduction catalyst converter, which is filled with a reduction catalyst for removing NOx (nitrogen oxide) in exhaust gas from the engine. A urea water tank 1 contains urea water (urea water) 1a which is a liquid reducing agent. 3 is a pump for supplying the urea water and air to the reduction catalytic converter 6, and 4 is an injector.
In such a reducing agent-utilizing exhaust gas purification apparatus, urea water from the urea water tank 1 through the urea water pipe 7 and air from the air pipe 11 are injected by the pump 3 through the urea water pipe 9 and the air pipe 12, respectively, to the injector 4. The urea water is atomized by injecting urea water into the air at the injector 4, and this atomized urea water is guided to the atomizer 5 through the ejection pipe 10, and is supplied from the atomizer 5 to the reduction catalytic converter 6. It is ejected to the upstream part of the reduction catalyst to promote the reduction catalyst reduction reaction.
Reference numeral 8 denotes a return pipe for returning excess urea water from the pump 3.
Reference numeral 2 denotes a surge tank for engine cooling water installed in the urea water tank 1 in an immersed state.

FIG. 1 is a configuration diagram around a urea water tank and a surge tank in the reducing agent-utilizing exhaust gas purification apparatus for an engine according to the first embodiment of the present invention shown in FIG.
In FIG. 1, 1 is the urea water tank, 2 is a surge tank for engine cooling water, 15 is an engine, 16 is a thermostat, 17 is a radiator, and 18 is a water pump.
In such an engine cooling water system, the high-temperature engine cooling water that has been heated by cooling the engine 15 is a thermostat 16, depending on whether the temperature is higher than the set temperature of the thermostat 16 or lower than the set temperature. The flow path changes, and the cooling water in the case of high temperature is sucked into the water pump 18 after being cooled to a predetermined temperature by the radiator 17. Cooling water in the case of low temperature is sent to the water pump 18.
Water that has been separated from air by the surge tank 2 is also introduced into the water pump 18, and the cooling water pumped by the water pump 18 is supplied to cooled parts such as a cylinder liner and a cylinder head of the engine.

The surge tank 2 is supplied with air mixed with water vapor from the air vent of the thermostat 16 and air mixed with water vapor from the air vent of the radiator 17 through the air vent pipe 19. The air mixed with water vapor is released into atmospheric pressure in the surge tank 2, thereby separating water into water and air in which water vapor is liquefied, and the cooling water is stored in the surge tank 2. After that, it is sucked into the intermediate portion between the water pump 18 and the radiator 17 through the cooling water pipe 20 as described above. Air is discharged from the air vent of the surge tank 2 into the atmosphere.
Due to the above action, the surge tank 2 stores relatively high-temperature (about 50 to 60 ° C. or higher) cooling water in which the water vapor is liquefied.

  In the first embodiment, the surge tank 2 is provided integrally with the urea water tank 1 in a form immersed in the urea water tank 1 containing the urea water (urea water) 1a, and the outer surface of the surge tank. And the urea water 1a are configured so that direct heat exchange is possible. Accordingly, during operation of the engine, the urea water 1a in the urea water tank 1 is heated by the heat of the cooling water in the surge tank 2 held at a relatively high temperature as described above, and the urea water 1a The freezing temperature is maintained at -11 ° C or higher.

  According to the first embodiment, during operation of the engine, the surge tank in which the engine cooling water on the engine outlet side, which is constantly maintained at a high temperature of about 50 to 60 ° C. or higher without being greatly affected by the atmospheric temperature, is accommodated. 2 is immersed in the urea water tank 1 so as to be integrated with the urea water tank 1 to exchange heat directly between the outer surface of the surge tank 2 and the urea water 1a. Since the urea water 1a in the urea water tank 1 is directly heated by the engine cooling water, the heat source composed of the engine cooling water is high temperature and the heat transfer surface having a wide heat transfer area constituted by the entire outer surface of the surge tank 2 The urea water 1a in the urea water tank 1 can be heated by the heat released from the water.

Further, since the urea water 1a in the urea water tank 1 is directly heated using the heat of the engine coolant that is relatively high, each of the devices disclosed in Patent Document 1 (Japanese Patent Application Laid-Open No. 2000-27627). A separate heating device for the liquid reducing agent is not required, and no special energy consumption for heating the urea water 1a is required, so that the heat of the engine cooling water can be effectively used and energy efficiency can be improved.
Further, according to the first embodiment, the surge tank 2 is immersed in the urea water tank 1 so as to directly exchange heat between the outer surface of the surge tank 2 and the urea water 1a. The structure of the apparatus is simplified, and the surge tank 2 is completely accommodated in the urea water tank 1, so that the apparatus is small and compact.

FIG. 2 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.
In the second embodiment, a plurality of heat transfer fins 2 a are provided on the outer surface 2 b of the surge tank 2 facing the inside of the urea water tank 1. In FIG. 2, the heat transfer fins 2 a are provided on the bottom surface of the surge tank 2, but the heat transfer fins 2 a are preferably provided on the entire outer surface 2 b immersed in the urea water 1 a of the surge tank 2.
According to the second embodiment, by providing a plurality of heat transfer fins 2a on the outer surface 2b of the surge tank 2, the heat transfer area between the surge tank 2 and the urea water 1a increases, and the surge tank 2 This improves the heating effect of the urea water 1a.
Other configurations and operational effects are the same as those of the first embodiment, and the same members and elements are denoted by the same reference numerals.

FIG. 3 is a configuration diagram around the urea water tank and the surge tank in the reducing agent-utilizing exhaust gas purification apparatus for an engine according to the third embodiment of the present invention, and FIG. 4 is an electric circuit diagram in the third embodiment.
In FIG. 3, reference numeral 25 denotes a heater provided at the bottom of the urea water tank 1, which heats urea water 1 a in the urea water tank 1 when energized by means described later. A heater circuit 26 energizes and shuts off the heater, and a heater controller 50 controls the operation of the heater circuit 26. Reference numeral 29 is a vehicle key ignition switch, 31 is a fuse, and 30 is a power supply for the heater 25.
28 is a urea water temperature sensor that detects the temperature of the urea water 1a accommodated in the urea water tank 1, and 27 is a urea water meter that detects the amount (water amount) of the urea water 1a. The urea water temperature detection value from the urea water temperature sensor 28 and the urea water amount detection value from the urea water meter 27 are input to the heater controller 50.

In the electric circuit diagram of this embodiment shown in FIG. 4, 29 is a vehicle key ignition switch, 31 is a fuse, and 30 is a power supply for the heater 25 (both of which are shown in FIG. 3).
A heater circuit 26 whose operation is controlled by the heater controller 50 is configured as follows.
Reference numeral 26a denotes a first heater circuit connected to the key ignition switch 29, and 26b denotes a second heater circuit connected to the normally open first heater switch 45 and the normally closed second heater switch 46. Reference numeral 26c denotes a third heater circuit for turning on and off the power to the heater 25 by a control signal from the heater controller 50.

  The first heater circuit 26a includes an exciting coil 40 connected to the key ignition switch 29 and contacts 42 and 41 which are turned on and off by the exciting coil 40. When the key ignition switch 29 is in an ON state, That is, when the engine is in an operating state, the exciting coil 40 is excited and the contact 42 is closed, and a circuit from the power source 30 to the heater 25 via the contact 42 is connected, and the current from the power source 30 receives the contact 42, The heater 25 is operated by flowing to the heater 25 through the normally closed contact 48.

  The second heater circuit 26b is a device for thawing the frozen urea water 1a without operating the engine in a cold region or the like. An excitation coil 43 connected to the first heater switch 45 and a contact 44 that is turned ON / OFF by the excitation coil 43. When the normally opened first heater switch 45 is turned ON, the excitation coil 43 is excited and the contact 44 is turned on. Is closed, and a circuit is connected from the power source 30 to the heater 25 via the contact 44, and a current from the power source 30 flows to the heater 25 through the contact 44 to operate the heater 25.

At this time, the engine 15 has stopped operating. That is, since the key ignition switch 29 is in an OFF state, the exciting coil 40 is in a non-excited state, and the contact 41 is in a closed contact state.
The first heater switch 45 is a normally open type switch that electrically connects the contact when pressed once, and automatically recovers when released to open the contact and interrupt the current. The so-called excitation holding circuit in which the current flowing through the contact point 41 flows from the contact point 41 to the exciting coil 43 through the normally closed second heater switch 46 and keeps closing the contact point 44 by the exciting force of the exciting coil 43. Forming.
Therefore, the first heater switch 45 is pressed once and the contact portion is opened even if the hand is released from the first heater switch 45, but the heater 25 is continuously energized. On the other hand, a pilot lamp 47 indicating that the excitation holding circuit is activated and energization of the heater 25 is continued is arranged in parallel with the excitation coil 43 so as to be lit.

In order to stop the second heater circuit 26b, when the normally closed second heater switch 46 is pushed, the contact of the second heater switch 46 is opened to interrupt the current. The second heater switch 46 automatically returns after operation, and the contact portion is normally closed.
Accordingly, since the exciting coil 43 and the pilot lamp 47 are not energized, the contact 44 is cut off from the current and the pilot lamp 47 is also turned off.
Also, when the key ignition switch 29 is operated, the second heater circuit 26b causes a current to flow through the exciting coil 40 of the first heater circuit 26a, so that the contact 42 is energized and the contact 41 is It will be cut off.
Accordingly, when the key ignition switch 29 is activated while the second heater circuit 26b is in operation, the second heater circuit 26b is configured to stop, so that the complicated operation of the driver is eliminated. Can do.
On the other hand, if the key ignition switch 29 is operated while the second heater circuit 26b is in operation, the first heater circuit 26a is operated, so that a circuit for energizing the heater 25 is secured, and the heater 25 is heated. Will continue.

The third heater circuit 26c is a circuit that supplies the current from the second heater circuit 26b to the heater 25. The third heater circuit 26c is based on a value obtained by detecting the temperature or the storage amount of the urea water 1a with a sensor. In accordance with a signal from the heater controller 50, the heater 25 is energized and shut off.
The urea water temperature sensor 28 that detects that the temperature of the urea water 1a is equal to or higher than a set value, or the urea water meter 27 that detects that the amount of water stored in the urea water 1a is below a predetermined value. When any one of the sensors senses, the third exciting coil 49 is energized based on a signal from the heater controller 50 and opens the contact 48 which is a normally closed contact to cut off the current, thereby interrupting the current of the heater 25. Stop heating.

Returning to FIG. 3, in the heater controller 50, the freezing temperature of urea water 1a (about −11 ° C.) is set, and when the first heater switch 45 is turned ON, as described above, excitation is performed. The contact 44 is closed by the excitation of the coil 43, and a current flows from the power supply 30 to the heater 25 via the contact 44 to operate the heater 25.
With this configuration, when the urea water 1a is frozen while the operation of the engine is stopped for a long time, such as at night in a cold region, the urea water 1a is heated by the heater 25 to release the freezing, and the engine smoothly You can get into driving. Further, even when the engine is operated in an extremely low temperature state where the urea water 1a is likely to be frozen, the freezing of the urea water 1a can be reliably avoided by using the heating by the surge tank 2 and the heating by the heater 25 in combination.

When the urea water 1a is being thawed while the engine is stopped in preparation for vehicle operation, the second heater circuit 26b is postponed due to circumstances and the thawing of the urea water 1a is stopped. In this case, it is possible to stop the second heater circuit 26b only by pushing the second heater switch 46 and opening the contact point, thereby eliminating the troublesome operation of the key ignition switch 29 and the heater by the pilot lamp 47. For example, forgetting to stop the heating operation 25 is prevented, and the heater 25 is turned off to save power.
Therefore, according to this embodiment, when the temperature detection value of the urea water 1a from the urea water temperature sensor 28 exceeds the allowable freezing temperature, the operation of the heater 25 can be automatically stopped. Therefore, the operating energy of the heater 25 can be saved, and when the operating energy of the heater 25 is covered by the engine, the fuel consumption rate of the engine can be reduced.

FIG. 5 is a view corresponding to FIG. 3 showing a fourth embodiment of the present invention.
In this embodiment, a manual switch 51 is installed in a circuit that connects the key ignition switch 29 and the heater 25, and the heater 25 is switched between on and off by turning on and off the manual switch 51. 31 is a fuse, and 30 is a power source for the heater 25. Other configurations are the same as those of the second embodiment shown in FIG. 2, and the same members are denoted by the same reference numerals.
A wide range of liquid reducing agents can be used in addition to the urea water 1a.

According to the present invention, even during operation in which the temperature of the liquid reducing agent is lowered, such as during low-temperature operation in a cold region of the engine, with a small and compact device without requiring special energy consumption, It is possible to provide a reducing agent-utilizing exhaust gas purification apparatus that can keep the liquid reducing agent temperature at or above the freezing temperature and avoid the freezing of the liquid reducing agent.
Can provide.

1 is a configuration diagram around a urea water tank and a surge tank in an engine exhaust gas purification apparatus using a reducing agent according to a first embodiment of the present invention. FIG. FIG. 3 is a view corresponding to FIG. 1 showing a second embodiment of the present invention. It is a block diagram around the urea water tank and surge tank in the reducing agent utilization type exhaust gas purification apparatus of the engine which concerns on 3rd Example of this invention. It is an electric circuit diagram in the third embodiment. FIG. 6 is a view corresponding to FIG. 3 showing a fourth embodiment of the present invention. It is a whole block diagram of the exhaust gas purification apparatus using a reducing agent of the engine to which the first embodiment is applied.

Explanation of symbols

1 Yulia water tank 1a Yulia water (urea water)
DESCRIPTION OF SYMBOLS 2 Surge tank 2a Heat transfer fin 2b Outer surface 3 Pump 4 Injector 6 Reduction catalytic converter 15 Engine 16 Thermostat 17 Radiator 18 Water pump 25 Heater 26 Heater circuit 27 Urea water quantity meter 28 Urea water temperature sensor 50 Heater controller

Claims (8)

  A liquid reductant that is provided with an engine cooling system that introduces high-temperature cooling water after engine cooling into the surge tank, and sends the cooling water separated from the air in the surge tank to the water pump, and stored in the reductant tank In a reducing agent utilizing exhaust gas purifying apparatus equipped with an exhaust gas purification system for supplying a reducing catalyst converter, the surge tank is placed in the reducing agent tank, the liquid reducing agent in the reducing agent tank, and the surge tank The reductant-utilizing exhaust gas purification apparatus is configured such that the liquid reductant is heated by heat from the surge tank.   2. The exhaust gas purification apparatus using a reducing agent according to claim 1, wherein the surge tank is provided with a plurality of heat transfer fins on an outer surface facing the liquid reducing agent tank.   3. The reducing agent-utilizing exhaust gas purification apparatus according to claim 1, wherein a heater for heating the liquid reducing agent is installed in a lower portion of the reducing agent tank.   A temperature sensor that detects the temperature of the liquid reducing agent stored in the reducing agent tank, and a temperature detection value of the liquid reducing agent from the temperature sensor are input, and based on the temperature detection value, the liquid reducing agent The exhaust gas purification apparatus using a reducing agent according to claim 3, further comprising a heater controller that operates the heater when the temperature is equal to or lower than a set allowable temperature.   The reductant amount meter for detecting the amount of the liquid reductant stored in the reductant tank is provided, and the heater controller is set with a reductant amount measurement value input from the reductant amount meter. 4. The exhaust gas purification apparatus using a reducing agent according to claim 3, wherein the operation of the heater is stopped when the capacity becomes the minimum capacity or less.   4. The reducing agent utilizing exhaust gas according to claim 3, wherein the heater controller is connected to a key ignition switch circuit of an engine and is configured to operate the heater when the key ignition switch is in an ON state. Purification equipment. The electric control circuit for controlling the current of the heater includes a first excitation coil that is excited by turning on a key ignition switch for starting the engine, and a first excitation coil that supplies current from the battery to the heater through the first excitation coil. A first heater circuit having a contact and a second contact that is linked to the first contact during the excitation operation of the first excitation coil and is a closed contact during the non-excitation,
A first heater switch that energizes current from the power source only during manual operation, a second excitation coil that is energized by energization of the first heater switch, and current from the power source that is energized by the excitation of the second excitation coil A normally-open third contact for energizing the first contact point, and when the second contact is closed from the downstream side of the third contact, the second excitation coil and the first heater switch are connected via the second contact. The second excitation coil is connected by exciting the second excitation coil, and a normally closed switch is provided between the second contact point and the second excitation coil to cut off the switch. And a second heater circuit having a second heater switch for stopping the excitation of the reducing agent using exhaust gas purifying apparatus according to any one of claims 3 to 6.   The second heater circuit is characterized in that a pilot lamp that is turned on when the second heater circuit is operated is arranged in parallel with the second exciting coil on the downstream side of the second heater switch. Item 8. An exhaust gas purification apparatus using a reducing agent according to Item 7.

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