JPH02163406A - Exhaust gas processing material feeding device for internal combustion engine - Google Patents

Abstract

PURPOSE:To permit the feed of the reducing agent for denitrification corresponding to the cyclic variation of the exhaust gas flow rate by increasing and decreasing the feed quantity of the exhaust gas processing material according to the reciprocation cycle of a piston for discharging exhaust gas. CONSTITUTION:Aqueous ammonia in a reducing agent tank 4 is introduced into a piston type pump 5 through a reducing agent feeding pipe 17, and when a piston 8 retreats, said aqueous ammonia is sucked into a cylinder 9, and when the piston 8 advances, said aqueous ammonia is discharged into a reducing agent injection pipe 18, and jetted into a Diesel engine outlet flue 14 from an injection nozzle 7, and mixed with the exhaust gas. The pump 5 is interlocked with the revolution of the Diesel engine 1 through a power transmission chain 11, and the revolution of an engine side rotary body 10 is transmitted to a pump side rotary body 12 through the chain 11, and the piston 8 is advanced and retreated by the movement of the piston 13. Further, the interlocking of the revolution of the engine 1 and the operation of the pump 5 leads to the sending-out of the aqueous ammonia to the nozzle 7, synchronized with the arrival of the exhaust gas discharged from one cylinder in the engine 1 to the nozzle part 7 through a flue 14.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to exhaust gas treatment for piston-type internal combustion engines, and in particular, to periodically controlling the supply amount of an exhaust gas treatment material in response to small periodic fluctuations in the exhaust gas flow rate. The present invention relates to an exhaust gas treatment material supply device for an internal combustion engine that is suitable for fluctuating the temperature.

[Conventional technology]

Fossil fuels such as coal and oil are currently widely used as energy sources in industry and daily life, but their combustion generates soot, carbon oxides, nitrogen oxides, etc. that are harmful to the human body. For this reason, laws and regulations require that harmful components in wandering gases be reduced by improving combustion methods, installing exhaust gas treatment devices, etc., and then releasing them into the atmosphere. This regulation begins with industrial boilers, power generation boilers, etc. that generate large amounts of exhaust gas, and gradually extends to private power generators, automobiles, etc.

In particular, air pollution in urban areas has recently attracted attention, and exhaust gas regulations have begun to be implemented for private power generators and automobiles that use diesel engines, but the problematic substances in diesel engine exhaust gas are soot and nitrogen oxides. However, there is a limit to how much they can be produced by improving combustion equipment, so development of methods to treat exhaust gases is actively underway.

As a method of treating nitrogen oxides in diesel engine exhaust gas, due to the presence of oxygen in the exhaust gas, the nitrogen oxides contained in the exhaust gas are converted to unburned carbon on a monolithic catalyst used in gasoline engines. Methods of reduction and purification using hydrogen and carbon oxides cannot be used, and as with conventional boiler exhaust gas, ammonia (NHj) is added to the exhaust gas.
) and other nitrogen oxide selective reducing agents are added to reduce the exhaust gas by bringing it into contact with a catalyst containing titanium oxide as the main component installed downstream of the exhaust gas.
It needs to be purified.

Currently, exhaust gas treatment devices using NH3 as a reducing agent, similar to the treatment of conventional boiler exhaust gas, are being installed to treat the exhaust gas of diesel engines having a power generation capacity of several hundred to several thousand kilowatts. These power generation devices operate multiple diesel engines with multi-cylinder combustion chambers, and when they merge and reach the denitrification equipment, the amount of exhaust gas is large. There is no particular problem if the treatment is performed using the same denitrification equipment as in the case of boiler exhaust gas treatment.

[Problem to be solved by the invention]

However, in the case of small-scale in-house power generation or in the case of automobiles, there is only one diesel engine, the number of cylinders is small, and depending on the driving load fluctuations, the engine often operates at low rotation speeds, so engine exhaust gas In response to fluctuations in the amount of exhaust gas, where the amount often increases and decreases in cycles as slow as several cycles of 7 seconds, it is not possible to supply the reducing agent at a constant flow rate, as in the case of conventional denitrification equipment.
When the amount of exhaust gas is high, the amount of reducing agent is insufficient, and when the amount of exhaust gas is low, the amount of reducing agent is excessive, resulting in a decrease in denitrification performance or an increase in the amount of unreacted reducing agent. be.

In conventional denitrification devices, no consideration was given to changing the reducing agent supply amount in accordance with the exhaust gas flow rate, which increases and decreases at several to several tens of cycles per second as described above. Furthermore, in terms of the response speed and follow-up performance of the component equipment, it is difficult to respond to small fluctuations in the exhaust gas flow rate.

The purpose of the present invention is to solve the problems of the prior art as described above, and to provide a reduction method for denitrification that responds to periodic fluctuations in exhaust gas flow rate that may be observed in piston-type internal combustion engines such as diesel engines. An object of the present invention is to provide an exhaust gas treatment material supply device capable of supplying an exhaust gas treatment material.

[Means to solve the problem]

The above object can be achieved in an internal combustion engine by providing a device that increases or decreases the amount of exhaust gas treatment material supplied in accordance with the reciprocating cycle of a piston that discharges exhaust gas.

Here, as a device for increasing and decreasing the supply amount, it is also possible to use a supply device using a piston type pump that operates in synchronization with the rotation of the internal combustion engine, and it is also possible to use a supply device that uses a piston type pump that operates in synchronization with the rotation of the internal combustion engine. It is also possible to use a device that changes the volume of the engine in synchronization with the rotation of the internal combustion engine.

Furthermore, if the rotational speed of the internal combustion engine increases and the fluctuations in the amount of exhaust gas emitted become smaller than a certain level, the fluctuations in the amount of exhaust gas are alleviated in the flue and can be regarded as a constant flow. Even if the occurrence of periodic fluctuations in the supply amount of the processing material is canceled when the number of times the supply amount exceeds the number, there will be no substantial inconvenience. If control is to be made simpler, it is desirable to cancel the pulsating flow of processing material supply at a predetermined rotation speed or higher and switch to a control system similar to the conventional one.

[Effect]

By configuring the exhaust gas treatment material supply device as described above, the amount of treatment material supplied changes synchronously with periodic fluctuations in the exhaust gas flow rate, so that an appropriate amount of exhaust gas treatment material is always present in the exhaust gas stream. will be supplied. Therefore, periodic excesses and deficiencies in the supply of processing material do not occur, as would occur when using prior art devices.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, the exhaust gas treatment material supply apparatus of the present invention will be specifically explained using examples.

Embodiment 1 FIG. 1 shows the configuration of an embodiment of an exhaust gas treatment material supply device of the present invention, in which ammonia water is injected and supplied from an injection nozzle 7 into the exhaust gas generated by a diesel engine 1.
In the denitrification reactor 2, the nitrogen oxides in the exhaust gas are reduced with ammonia to render them harmless, and then released into the atmosphere through the silencer 3. In this device, a reducing agent tank 4 for storing aqueous ammonia and an injection nozzle 7 are used. This figure shows that a piston type pump 5 according to the present invention is provided in between, which operates in conjunction with the rotation of the diesel engine.

More specifically, the ammonia water in the reducing agent tank 4 reaches the piston type pump 5 via the reducing agent supply pipe 17, is sucked into the cylinder 9 when the piston 8 moves backward, and is drawn into the reducing agent injection pipe when moving forward. It is discharged to I8, injected from the injection nozzle 7 to the diesel engine outlet flue 14, and mixed with the exhaust gas. Here, the piston pump 5 is linked to the rotation of the diesel engine 1 through a power transmission chain 11, and the rotation of the engine side rotating body 10 is transmitted to the pump side rotating body 12 via the power transmission chain 11, and the crank 13 is Move the piston 8 forward and backward. Also,
The rotation of this diesel engine 1 and the piston pump 5
The piston of the piston pump 9 is linked to the operation of the piston pump 9 in synchronization with the time when the exhaust gas discharged from any cylinder in the diesel engine 1 passes through the diesel engine outlet flue 14 and reaches the injection nozzle 7. The sizes of the engine-side rotary body 10 and the pump-side rotary body 12 and the connection positions with the power transmission chain 11 are combined so that the engine 8 moves forward and sends ammonia water to the injection nozzle 7.

As explained above, the amount of ammonia water supplied by the piston pump 5 increases or decreases depending on the amount of exhaust gas generated by the diesel engine 1, so rough reducing agent flow rate control can be performed by the piston pump, but depending on the fuel type. When the amount of gas required to be treated per unit flow rate of exhaust gas changes, such as when changing from kerosene to heavy oil, and therefore the supply reducing agent must be changed, the piston pump 5 is used.
It is necessary to further adjust the amount of reducing agent supplied by
This can be handled by adjusting the flow rate of the ammonia water that returns to the inlet of the piston pump 5 via the flow rate control valve 6 via the flow rate control valve 6. In addition, the flow rate control valve 6 can be used as an automatic valve connected to the same conventional control system even when the reducing agent flow rate is precisely controlled as in a conventional large boiler exhaust gas denitrification device. can.

By using the exhaust gas treatment material supply device as configured in this embodiment, it is possible to supply the required amount of ammonia water only when exhaust gas is discharged from the diesel engine, making it possible to use a conventional constant-speed supply device. The phenomenon in which excess and insufficient supply of the exhaust gas treatment material are periodically repeated will no longer occur as in the case where the exhaust gas treatment material is supplied.

Embodiment 2 The configuration of another embodiment of the exhaust gas treatment material supply device of the present invention is shown in FIG. 17
This is done by expanding or contracting the space provided between the pipe 18 and the reducing agent injection pipe 18. That is, like the conventional denitrification device, this device supplies ammonia gas from a reducing agent tank (in this case, an ammonia gas cylinder) 4 to an injection nozzle 7 via a flow rate control valve 6 at a flow rate depending on the exhaust gas flow rate and the concentration of nitrogen oxides in the exhaust gas. In.

A pulsating flow generator 20 is provided between the reducing agent supply pipe 17 and the reducing agent injection pipe 18 to generate a pulsating flow of ammonia gas in accordance with the rotation of the diesel engine 1. Here, the movable piece 22 of the pulsating flow generator 20 is pushed by the rotation of the cam 24 that interlocks with the engine-side rotating body 10 via the power transmission 11, and is also pulled back by the return spring 23.

As a result of the shrinkage and expansion of the space surrounded by the outer wall 21 of the pulsating flow generator, the ammonia gas supplied at a constant flow rate along with the diluent gas supplied from the diluent gas pipe 25 through the reducing agent supply pipe 17 becomes a pulsating flow here. and is discharged to the reducing agent injection pipe 18 side, and is injected from the injection nozzle/luer in synchronization with the pulsating flow of the exhaust gas.

Embodiment 3 The structure of yet another embodiment of the exhaust gas treatment material supply apparatus of the present invention is shown in FIG. The features of this embodiment are that the function of the movable piece 22 in Embodiment 2 is performed by an electromagnetic movable piece, and that the pulsating flow generation control of reducing agent supply is performed by an electric signal from an operation signal generator. be.

That is, first, the structure is such that the generation timing of exhaust gas in the diesel engine 1 is detected by contact between a contact piece 33 provided on the outer periphery of the engine-side rotating body 10 and a contact detector 32 provided at a fixed position. The contact timing between the piece 33 and the contact detector 32 is adjusted to be synchronized with the exhaust gas discharge timing in the diesel engine 1. The signal emitted from the contact detector 32 is transmitted through the contact signal line 31 into a pulsating flow. The signal reaches the actuation signal generator 30 of the generator 20, and within the actuation signal generator 30, processing is performed according to the flowchart shown in FIG. Only when the flow is significant, an activation signal is sent to the pulsating flow generator 20 via the electromagnet activation signal line 29 so as to generate a pulsating flow of reducing agent supply corresponding to the pulsating flow of exhaust gas. In this embodiment, the pulsating flow generator 20 is composed of an electromagnetic movable piece 26 that can reciprocate, an electromagnet 27 that moves the electromagnetic movable piece 26, and an electromagnetic coil 28 that applies magnetic force to the electromagnet 27. When an activation signal is input from 29, a current flows through the electromagnetic coil 28 and magnetic force is generated in the electromagnet 27, and the electromagnetic movable piece 26 is pushed in by the repulsion of the magnetic force.If there is no activation signal, the electromagnetic movable piece 26 is pushed in by the magnetic force. As a result of being pulled back, as in the case of the pulsating flow generator 20 of the second embodiment, a pulsating flow of reducing agent supply corresponding to the pulsating flow of exhaust gas at the injection nozzle 7 is generated.

In addition, in the above explanation, we have described the case where the generation of pulsating flow of reducing agent supply is performed using the movement of a movable body by an electromagnet, but if the period of fluctuating gas amount fluctuation is long, the response speed will be slightly slower. However, it is naturally possible to generate this by controlling a step motor.

〔Effect of the invention〕

As described above, the exhaust gas treatment material supply device for a piston-type internal combustion engine is a device configured according to the present invention, that is, a device that can increase or decrease the supply amount of the exhaust gas treatment material in accordance with the reciprocating cycle of the piston that discharges exhaust gas. By doing so, it has become possible to solve the problems of the conventional technology and to always supply an appropriate amount of exhaust gas treatment material, with no excess or deficiency, in response to periodic fluctuations in the amount of exhaust gas. Ta.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of one embodiment of the exhaust gas treatment material supply device of the present invention, FIG. 2 is a diagram showing the configuration of another embodiment of the exhaust gas treatment material supply device of the present invention, and FIG. FIG. 4 is a diagram showing the configuration of still another embodiment of the exhaust gas treatment material supply device of the invention.
The figure is a flowchart showing processing within the actuation signal device of the third embodiment. 1... Diesel engine 2... Denitration reactor 3... Silencer 4... Reducing agent tank 5... Piston type pump 6... Flow rate adjustment valve 7... Injection nozzle 8... piston
9...Cylinder 10...Engine side rotating body 11...Power transmission chain 12...Pump side rotating body 13...Crank 14...Diesel engine outlet M, M15...Denitrifier outlet Flue 16... Flue gas release flue 17...
Reducing agent supply pipe 18...Reducing agent injection pipe 19...
・Reducing agent return piping 20... Pulsating flow generator 21... Outer wall 22... Movable piece 23... Pullback spring 24... Cam 25... Diluent gas piping 26
...Electromagnetic movable piece 27...Electromagnet 28...
・Electromagnetic coil 29...Electromagnet operation signal line 30...Operating signal generator 31...Touch signal line 32
...Contact detector 33...Rotating body outer periphery contact piece 4th

Claims (1)

[Claims] 1. In an apparatus for supplying an exhaust gas treatment material that reacts with a specific component in the exhaust gas to purify the exhaust gas generated from a piston-type internal combustion engine and whose flow rate fluctuates periodically, 1. An exhaust gas treatment material supply device for an internal combustion engine, comprising means for periodically varying the supply amount of the exhaust gas treatment material in accordance with fluctuations in the exhaust gas treatment material. 2. Claim 1, characterized in that a piston-type pump that operates in synchronization with the rotation of the internal combustion engine is used as the means for periodically varying the supply amount of the exhaust gas treatment material.
An exhaust gas treatment material supply device for an internal combustion engine as described in 2. 3. The means for periodically varying the supply amount of the exhaust gas treatment material is characterized by using means for periodically expanding and contracting the volume of the exhaust gas treatment material supply line in accordance with the reciprocating period of the piston of the internal combustion engine. An exhaust gas treatment material supply device for an internal combustion engine according to claim 1. 4. As a means to periodically increase/decrease the capacity of the exhaust gas treatment material supply line, it is reversible so that when a load is applied to a part of the supply line, the supply line is pulled into the piping, and when the load is removed, it returns to its original position. Exhaust gas treatment in an internal combustion engine according to claim 3, characterized in that the movable body is a reversible movable body that operates intermittently according to the reciprocating cycle of a piston of the internal combustion engine. Material supply device. 5. A device that supplies an exhaust gas treatment material that purifies exhaust gas generated from a piston internal combustion engine and whose flow rate fluctuates periodically by reacting with specific components in the exhaust gas. In an exhaust gas treatment material supply device having means for periodically varying the supply amount of the treatment material, when the rotational speed of the internal combustion engine exceeds a predetermined set value, the periodic fluctuation of the exhaust gas treatment material supply amount is stopped; 1. An exhaust gas treatment material supply device for an internal combustion engine, comprising means for switching to constant speed supply at a predetermined flow rate.