JPH0660725U - Exhaust gas purification device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] H added as a reducing agent in an exhaust gas purifying apparatus for an internal combustion engine equipped with a reducing catalyst to remove NO _x
C prevents the nozzle of the injector from clogging. A mounting boss 45a is formed on a pipe wall of an exhaust pipe 45 of an internal combustion engine, and an injector 110 of a hydrocarbon adding device 100 is attached to the mounting boss 45a. The injector 110 is connected to the fuel tank via the adjusting valve 120 and the pipe 115, and receives the supply of hydrocarbon as a NOX reducing agent.
A heater 140 is attached to the front surface of the nozzle 112 of the injector 110 via a packing 130. The heater 140 is connected to a power source via harnesses 142 and 144. By operating the heater 140, the nozzle 1
Carbon and the like deposited on the front surface of 12 are burned and removed, and the clogging of the nozzle is prevented.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

The present invention relates to a device for removing nitrogen oxides (NO _x ) contained in exhaust gas of an internal combustion engine.

[0002]

[Prior art]

Activated alumina (r-alumina) or a zeolite-based catalyst synthesized from S ₁ O ₂ and Al ₂ O ₃ is used as a means for removing NO _{x in} the gas discharged from internal combustion engines such as gasoline engines and diesel engines. It is known to be effective, and is disclosed in, for example, JP-A-63-283727 and JP-A-3-253713. As the zeolite-based catalyst, for example, mordenite or H-ZSM5 is used, and this catalyst exerts an effect as a NO _X reducing agent when hydrocarbon (HC) is present in substantially the same amount as NO _X. Usually, the amount of HC contained in the exhaust gas is not less than the amount of NO _X. Therefore, in the NO _X removal device equipped in the internal combustion engine, an HC addition device is installed upstream of the catalyst provided in the exhaust pipe line to restore the NO _X concentration of HC in the exhaust gas. Adjust to an easy value. Considering the easiness of vaporizing HC, the position where the HC addition device is arranged is preferably near the exhaust port of the cylinder head where the exhaust gas has a high temperature or at an upstream position of the exhaust manifold.

[0003]

[Problems to be solved by the device]

It is desirable that the reducing agent injector installed in the exhaust pipe be installed as close to the exhaust valve as possible to add the reducing agent to the exhaust gas having a high temperature. However, since the exhaust gas flowing into the exhaust pipe contains particulates such as carbon, carbon adhered to the injector provided in the exhaust pipe, which was a cause of poor flow rate adjustment of the additive. Therefore, the present invention provides a device for eliminating the above-mentioned problems by providing a heater in front of the injector nozzle to burn carbon. A device provided with a heater at the tip of a nozzle for injecting fuel into the combustion chamber of an internal combustion engine is disclosed in Japanese Patent Application Laid-Open No. 4-103828 by the present applicant. The device of the above-mentioned publication is for promoting evaporation and ignition of fuel, and is not a device for incinerating carbon or the like deposited on the nozzle of the injector to which the NO _X reducing agent is added.

[0004]

[Means for Solving the Problems]

 As a concrete means, the present invention includes a hydrocarbon addition device provided in an exhaust pipe, an injector for injecting hydrocarbons provided in an exhaust manifold, a heater for heating a front surface of a nozzle of the injector, and an operation of the injector and the heater. It has a controller to control it.

[0005]

[Action]

By operating the heater at an appropriate timing, the carbon etc. adhering near the nozzle of the injector for adding the reducing agent is incinerated and the nozzle clogging is prevented. Therefore, the amount of the reducing agent added is accurately controlled, and the NO _x reduction efficiency is also improved.

[0006]

【Example】

FIG. 1 shows an embodiment of an NO _X removal device for an internal combustion engine according to the present invention. A cylinder block 10 has a cylinder head 20 corresponding to the number of cylinders, and each cylinder head 20 has an intake port of an intake manifold 30. 32 communicates. Fuel is injected into each cylinder head 20 by the main injection device, and combustion is performed. The exhaust gas that has finished burning flows out from the exhaust port 42 to the exhaust manifold 40. The exhaust manifold 40 has branch pipes 40A, 40B, 40C, 40D branched into the number of cylinders, and each branch pipe is integrated into one exhaust pipe 45. The reduction catalyst 60 is arranged in the midway of the exhaust pipe 45.

The HC addition device 100 is disposed, for example, in the most upstream part of the exhaust pipes 45 that are integrated. A temperature sensor 90 is provided at the inlet of the reduction catalyst 60 to detect the temperature of exhaust gas flowing into the catalyst 60 and send it to the controller 80 via a line 92. A water temperature gauge 95 is provided on the cylinder block and sends the temperature of the cooling water to the controller 80 via a line 97. Information about the engine speed N and the engine load L is input to the controller 80 in addition to the cooling water temperature and the exhaust temperature.

The HC addition device 100 receives the supply of HC from a dedicated tank for HC or a fuel tank 70 of an internal combustion engine, and supplies the HC to the exhaust manifold 40 by an injector provided in the HC addition device via a pipe 115. Added. The HC addition device 100 includes a flow rate adjusting valve, and the opening degree of the valve is controlled by the controller 80. The controller 80 controls the HC injection amount of the injector via the line 82 based on the information on the engine speed and the load. The EGR pipe 50 has an intake port 52 communicating with the exhaust manifold 40 and a discharge port 54 communicating with the intake manifold 30, and recirculates a part of the exhaust gas to the intake system.

FIG. 2 is an explanatory diagram showing the details of the HC addition device 100. A through hole is provided in the mounting boss 45a provided on the wall of the exhaust pipe 45, and the injector 110 is attached thereto. The injector 110 is connected to the fuel tank 70 via a pipe 115. The injector 110 has a regulating valve 120, and the regulating valve 120 is opened and closed by an actuator 125. By controlling the opening of the actuator by the signal sent from the controller 80 via the line 82, the flow rate of the reducing agent injected from the nozzle 112 of the injector 110 is adjusted.

A heater 140 is disposed on the front surface of the nozzle 112 via a packing 130. The heater 140 has a ring shape, and the reducing agent is ejected through the central opening 141. The heater 140 is of an electric heating type, for example, and is connected to the power source 150 by harnesses 142 and 144. The pipe wall of the exhaust pipe 45 is formed with holes 46 for passing the harnesses 142, 144. The opening and closing of the switch of the power supply 150 is controlled by the controller 80 via the line 152.

The reducing agent injected from the nozzle 112 of the injector 110 is atomized into the exhaust gas in the exhaust pipe 45 through the opening 141 of the heater 140. When the engine is cold and the temperature of the cooling water is low, carbon in the exhaust gas is likely to adhere to the front surface of the nozzle 112. The controller 80 determines this state and issues a command to the power source via the line 152 to activate the heater 140.

The heater 140 is heated to, for example, about 800 ° C., and incinerates and removes deposits in the vicinity of the front surface of the nozzle 112 of the injector 110. The heater 140 need not operate at all times, and the controller 80 only activates the heater when needed to save power. The packing 130 interposed between the nozzle 112 and the heater 140 also serves as a heat insulating material. The reducing agent injected from the nozzle is heated by the heater 140 to promote atomization, so that it is uniformly added to the exhaust gas. Therefore, the NO _x reduction efficiency of the catalyst 80 is also improved.

[0013]

[Effect of device]

This invention, as described above, disposed reduction catalyst in an exhaust pipe of an internal combustion engine, by adding hydrocarbons to the exhaust pipe upstream of the reduction catalyst as a reducing agent, to divided the NO _X in the exhaust gas In an exhaust gas purification device, a hydrocarbon addition device is composed of an injector for injecting fuel and a heater arranged in front of a nozzle of the injector. The heater incinerates carbon and other deposits adhering to the front of the injector nozzle at high temperature. As a result, the passage of the nozzle is normally secured, and the reducing agent can be added in an accurate amount. In addition, the reducing agent can be heated if necessary, which improves the atomization situation. Therefore, it is uniformly added to the exhaust gas, and the NO _x reduction efficiency is also improved.

[Submission date] February 12, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

FIG. 2 is an explanatory diagram showing the details of the HC addition device 100. A through hole is provided in the mounting boss 45a provided on the wall of the exhaust pipe 45, and the injector 110 is attached thereto. The injector 110 is connected to the fuel tank 70 via a pipe 115. A signal sent from the controller 80 via the line 82 adjusts the flow rate of the reducing agent injected from the nozzle 112 of the injector 110.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention.

FIG. 2 is an explanatory view showing details of a hydrocarbon addition device.

[Explanation of symbols]

 10 Cylinder Block 20 Cylinder Head 30 Intake Manifold 32 Intake Port 40 Exhaust Manifold 42 Exhaust Port 45 Exhaust Pipe 50 EGR Pipe 52 EGR Suction Port 54 EGR Discharge Port 60 Reduction Catalyst 70 Fuel Tank 80 Controller 100 HC Addition Device 110 Injector 112 Nozzle 140 Heater 150 power supply

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[Procedure amendment]

[Submission date] February 12, 1993

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

Claims (1)

[Scope of utility model registration request] 1. An exhaust pipe connected to an exhaust port of a cylinder block of an internal combustion engine via an exhaust manifold, a reduction catalyst provided in the exhaust pipe, and an exhaust pipe provided upstream of the reduction catalyst. In an internal combustion engine provided with a device for adding hydrocarbons to exhaust gas, the hydrocarbon adding device is an injector for injecting hydrocarbons provided in an exhaust manifold,
An exhaust gas purification apparatus for an internal combustion engine, comprising: a heater provided in front of a nozzle of the injector; and a controller that controls the injection amount of the injector and the operation of the heater according to the operating state of the internal combustion engine.