Emission treatment system and control method

An emission treatment system for a vehicle is provided that includes a plasma reactor is disposed in a main exhaust pipe and configured to reduce noxious emissions of an engine. A bypass pipe is connected to the main exhaust pipe both before and after the plasma reactor such that exhaust emissions can be caused to bypass the plasma reactor. A control valve is disposed at a position where the main exhaust pipe and the bypass pipe intersect, and is configured to selectively open and close the main exhaust pipe and the bypass pipe. A power supply unit supplies power to the plasma reactor and the control unit is coupled to the power supply unit and the control valve controlling a voltage of power supplied to the plasma reactor and an operation of the control valve.

FIELD OF THE INVENTION

Generally, the present invention relates to a vehicle emission treatment system. More particularly, the present invention relates to a system and control method for vehicle emission treatment that includes a plasma reactor.

BACKGROUND OF THE INVENTION

Conventionally, some vehicles include a plasma reactor incorporated into the exhaust pipe to treat emissions. Generally, the plasma reactor efficiently reduces noxious gaseous materials and noxious particles that are exhausted from an engine. The plasma reactor requires high-voltage electric power to reduce these emissions. However, the high-voltage systems often suffer from short circuits and open circuit failures.

Often the plasma reactor short circuits when excessive particles accumulate on a surface of the plasma reactor. The open circuit failure occurs by a malfunction of a power supply system caused by vibrations from the vehicle or other mechanical failures to the system.

Associated with plasma reactors generally is a system that uses an optimal power map to adjust the functioning of the plasma reactor to the operating conditions of the engine. However, a drawback of such systems is that they do not focus on stabilizing the plasma reactor system.

SUMMARY OF THE INVENTION

In a preferred embodiment of the present invention, an emission treatment system for a vehicle comprises a plasma reactor, a power supply unit, a direct-connecting pipe, a bypass pipe, a control valve, and a control unit. The plasma reactor is configured to reduce noxious emissions of an engine, and is positioned at one end of an exhaust pipe. The power supply unit supplies power to the plasma reactor. The direct-connecting pipe is configured to connect the plasma reactor to the exhaust pipe such that exhaust emissions can pass through the plasma reactor. The bypass pipe is connected to the direct-connecting pipe both before and after the plasma reactor such that the exhaust emissions can bypass the plasma reactor. The control valve is disposed at a position where the direct-connecting pipe and the bypass pipe intersect, and is configured to selectively open and/or close the direct-connecting pipe and/or the bypass pipe. The control unit is coupled to the power supply unit and the control valve and controls the voltage of power supplied to the plasma reactor and an operation of the control valve.

It is preferable that the power supply unit comprises a power source unit, a transformer, a high-voltage plug, and a high-tension cord. The power source unit provides power to the plasma reactor. The transformer is configured to boost a voltage of power supplied from the power source unit to the plasma reactor. The high-voltage plug is disposed beside the plasma reactor and configured to stably supply the boosted power to the plasma reactor. A high-tension cord connects the power source unit to the transformer and the transformer to the high-voltage plug.

Preferably, the power source unit comprises a battery of the vehicle. It is also preferable that the power source unit comprises a first alternator of the vehicle. It is also preferable that the power source unit comprises a second alternator of the vehicle.

In a preferred embodiment that the emission treatment system further comprises a warning lamp illuminated by a control signal from control unit in order to warn of a malfunction of the plasma reactor.

In another preferred embodiment the method for controlling an emission treatment system including a plasma reactor comprising applying power to the plasma reactor configured to reduce noxious emissions of an engine. Detecting a primary voltage and a primary current of a transformer to boost the voltage of power supplied to the plasma reactor. Determining whether the primary voltage of the transformer is less than a predetermined voltage. Determining whether the primary current of the transformer is less than a predetermined voltage if it is determined that the primary voltage is less than the predetermined voltage. Closing a bypass pipe such that exhaust emissions do not bypass the plasma reactor, and opening a direct-connecting pipe configured such that exhaust emissions pass through the plasma reactor, if it is determined that the primary current is less than a predetermined current.

It is also preferable that the method further comprises stopping power supplied to the plasma reactor if it is determined that the primary voltage of the transformer is not less than the predetermined voltage. It is further preferable that the method further comprises opening the bypass pipe and closing the direct-connecting pipe if it is determined that the primary current is not less than the predetermined current.

In a further preferred embodiment of the present invention, the emission treatment system comprises a plasma reactor, a bypass pipe, a control valve, a power supply unit, and a control unit. The plasma reactor is disposed in a main exhaust pipe, and is configured to reduce noxious emissions of an engine. The bypass pipe is connected to the main exhaust pipe both before and after the plasma reactor such that exhaust emissions can bypass the plasma reactor. The control valve is disposed at a position where the main exhaust pipe and the bypass pipe intersect, and is configured to selectively open and/or close the main exhaust pipe and/or the bypass pipe. The power supply unit supplies power to the plasma reactor. The control unit is coupled to the power supply unit and the control valve and controls a voltage of power supplied to the plasma reactor and operations of the control valve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown inFIG. 1, an emission treatment system according to a preferred embodiment of the present invention includes a plasma reactor10that is incorporated into an exhaust pipe from an engine1of a vehicle. A plasma range where corona discharge occurs is formed in the plasma reactor10, and noxious material of exhaust gases is reduced while the exhaust gases pass through the plasma range.

A power supply unit60is configured to supply high-voltage electric power to the plasma reactor10and is electrically connected to the plasma reactor10. The plasma reactor10is disposed in a direct-connecting pipe31, which connects the plasma reactor10to the exhaust pipe of the engine1such that exhaust gases pass through the plasma reactor10.

In an alternative embodiment and depending upon the particular application requirements, the direct-connecting pipe31can be a portion of the exhaust pipe that connects the engine1and a tailpipe33. A bypass pipe32connects the direct-connecting pipe31both before and after the plasma reactor10such that the exhaust gases can flow from the engine1to a tailpipe33without passing through the plasma reactor10, in response to a control valve40setting. The control valve40is disposed at a position where the direct-connecting pipe31and the bypass pipe32intersect. The control valve40is configured to selectively open and close the direct-connecting pipe31and the bypass pipe32so the flow path of the exhaust gases between the engine1and the tailpipe33can be regulated.

The emission treatment system further includes a control unit50configured to control the power supply unit60and the control valve40. Therefore, the power supplied to the plasma reactor10and the flow of the exhaust gas can be regulated by the control unit50. Preferably, the control unit50includes a processor, a memory, and other necessary hardware and software components as will be understood by persons skilled in the art, to permit the control unit50to execute the control functions as described herein.

The power supply unit60includes a high-voltage power source unit62, a transformer61configured to boost the voltage of power supplied from the high-voltage power source unit62, a high-voltage plug64for stably supplying the boosted power to the plasma reactor10, and a high-tension cord63that connects the high-voltage power source unit62to the transformer61and to the high-voltage plug64.

In a preferred embodiment the high-voltage power source unit62may be a battery (not shown). In alternative embodiments the high-voltage power source unit62may be a first alternator (not shown) of a vehicle or a second alternator (not shown) of the vehicle.

It is preferable that the emission treatment system of the present invention further includes a warning lamp70illuminated by a control signal from the control unit50in order to warn a driver of a malfunction of the plasma reactor10. It is also preferable that illumination of the lamp70occurs when the plasma reactor malfunctions in an open circuit state. In alternative embodiments it is evident that the warning lamp70can be replaced by an alarm, a buzzer, or the like.

Finally, the exhaust emissions flow through the tailpipe33after passing through the direct-connecting pipe31and the plasma reactor10, or after passing through the bypass pipe32if directed so by the control unit50and the control valve40.

The operation of the emission treatment system according to an embodiment of the present invention is described below.

The control unit50controls voltage and current supplied to the transformer61from the high-voltage power source unit62based on a predetermined voltage/current map which accords to the driving conditions.

The transformer61boosts the voltage of the electric power supplied from the high-voltage power source unit62, and then supplies the boosted power to the plasma reactor10. Primary voltage (input voltage) V0of the transformer61and primary current (input current) I0of the transformer61are fed to the control unit50. The control unit50determines whether the plasma reactor10is in an open circuit state or in a short circuit state based on the primary voltage V0and the primary current I0of the transformer61. According to a result of this determination, the control unit50outputs a control signal to control the control valve40such that the main exhaust pipe31or the bypass pipe32is opened or closed. That is, if it is determined that the plasma reactor10is neither in the open circuit state nor in the short circuit state, the control unit50controls the control valve40to close the bypass pipe32such that exhaust emissions will pass through the plasma reactor10. However, if it is determined that the plasma reactor10is in the open circuit state, the control unit50controls the warning lamp70to illuminate in order to warn a driver of a malfunction of the plasma reactor10. Furthermore, upon determination that the plasma reactor10has short circuited, the control unit50signals the control valve40to close the direct-connecting pipe31and open the bypass pipe32such that exhaust emissions flow through the bypass pipe32to the tailpipe33without passing through the plasma reactor10. Durability and stability of the plasma reactor10is increase and power consumption decreases by incorporation of the bypass pipe32.

In an alternate embodiment, when a vehicle operates in operating modes other than an emission mode, it is preferable that the direct-connecting pipe31and the bypass pipe32are open at predetermined amounts. In this configuration the control valve40is open to a predetermined map angle.

FIG. 2shows a flowchart of the emission reduction control method using the emission reduction system according to an embodiment of the present invention.

First, the control unit50receives signals relating to vehicle driving conditions, calculates a target voltage output from the high-voltage power source unit62, then signals the high-voltage power source unit62to generate the target voltage in step110. A voltage of electric power output from the high-voltage power source unit61is boosted by the transformer62, and is then supplied to the plasma reactor10. The control unit50then detects the primary voltage V0and the primary current I0of the transformer61in step120. Next, the control unit50determines whether the primary voltage V0of the transformer61is less than a predetermined voltage VLin step130.

When the plasma reactor10operates normally, a voltage applied to the plasma reactor10generally decreases, so the primary voltage supplied by the transformer61decrease accordingly. However, if the primary voltage of the transformer61is not less than a predetermined voltage, the plasma reactor10is in the open circuit state. Thus, the control unit50illuminates the warning lamp70to warn a driver the plasma reactor10is in an open circuit condition. The control unit50also terminates the power supply to the plasma reactor10in step210.

If the primary voltage V0of the transformer61is less than the predetermined voltage VL, step130, the control unit50determines whether the primary current I0of the transformer61is less than a predetermined current IL, in step140. When the plasma reactor10operates normally, a small current flows between two electrodes of the plasma reactor10. However, if the plasma reactor10short circuits, a large current flows between the two electrodes of the plasma reactor10. Therefore, when the primary current of the transformer is not less than the predetermined current, the plasma reactor10has short circuited. Thus, if it is determined that the primary current I0of the transformer61is not less than the predetermined current ILin step140, the control unit50controls the control valve40such that the direct-connecting pipe31is closed and the bypass pipe32is open. Furthermore, the control unit50controls the primary voltage and the primary current of the transformer such that a specific level of power is supplied to the plasma reactor10in step220. In use, upon determination that the plasma reactor10has short circuited, exhaust emissions are prevented from flowing through the plasma reactor10and a specific level of power is supplied to the plasma reactor10so that the plasma reactor10may perform a self-cleaning process.

If it is determined that the primary current I0of the transformer61is less than the predetermined current IL, in step140, the control unit50controls the control valve40such that the direct-connecting pipe31is open and the bypass pipe32is closed, step150. The control unit50then controls the high-voltage power source unit62such that power is supplied to the plasma reactor10, step160.

In use, it is possible to guarantee a stable operation of the plasma reactor and to reduce power consumption of the plasma reactor by allowing the plasma reactor to perform a self-cleaning process through control of the control valve. Therefore, the exhaust gases flow through the bypass pipe without passing through the plasma reactor if it is determined that the plasma reactor has short circuited.

Although alternate embodiments of the present invention have been described in detail it should be understood that many variations and modifications of the basic inventive concepts taught herein may appear to those skilled in the art. Furthermore, the above described embodiments are not intended to be an exhaustive list of the embodiments of the present invention as the present invention is intended to by defined by the sprit and scope of the appended claims.