Abstract: In an exhaust gas purifying technique in which discharge is utilized, the invention provides a technique in which purification efficiency can be enhanced while an increase in electric power consumption is suppressed. A discharge mode including a discharge period and an undischarged period is adopted in a configuration in which a plasma process is performed to exhaust gas from a Diesel engine by generating the discharge in a plasma generator. A basic waveform periodically exists in a repeated manner in the discharge period, and the discharge is not performed in the undischarged period. An amplitude and/or a period of the basic waveform is controlled according to a load on the Diesel engine, a continuous iteration count of the basic waveform is controlled according to purification reaction efficiency in the plasma process, and the burst period is controlled according to an exhaust gas flow rate.

Abstract: An exhaust gas purification system that is equipped, from an upstream side toward downstream side through which an exhaust gas flows, with a plasma reactor and a NOx selective reduction catalyst unit having a NOx selective reduction catalyst layer acting on the exhaust gas, and which system provides a reducing agent adding means adding a reducing agent to the exhaust gas at an upstream side of the plasma reactor, wherein the NOx selective reduction catalyst layer comprises nickel and a NOx selective reduction catalyst or wherein the NOx selective reduction catalyst layer contains ?-alumina that supports magnesium or wherein the NOx selective reduction catalyst unit comprises a first purification unit where an exhaust gas via the plasma reactor is introduced, and a second purification unit where an exhaust gas via the first purification unit is introduced.

Abstract: The present invention is to provide a sensing device and method for direct measurement of a concentration of PM contained in exhaust gas and measurement of PM concentration in an exhaust pipe: a power supply unit (10); an electrode unit (11) fitted in the exhaust pipe and composed of a pair of parallel flat plates; and a sensing unit (12) for measuring electrical characteristics of the electrode unit (11) after the power supply unit (10) applies a predetermined voltage to the electrode unit (11) and PM contained in exhaust gas inside the exhaust pipe is deposited onto the electrode unit (11), and for sensing the concentration of the PM contained in the exhaust gas inside the exhaust pipe from the measured electrical characteristics.

Abstract: In a plasma generating electrode 1, at least one of opposing unit electrodes 2 includes a sheet-shaped ceramic dielectric 3 and a conductive film 4 disposed in the ceramic dielectric 3 and partially extending on the surface of the ceramic dielectric 3 opposite to the other unit electrode 2 on the end of the ceramic dielectric 3, and a conductive terminal 5 is electrically connected with the conductive film 4 extending on the surface of the ceramic dielectric 3 opposite to the other unit electrode 2 on the end of the ceramic dielectric 3. Therefore, simple and reliable electrical connection can be achieved.

Abstract: A plasma generation electrode capable of subjecting predetermined components contained in a fluid to be treated to their respective reaction treatments with plasmas having different intensities optimized on a reaction basis, by passing merely once the fluid to be treated, is provided. In the plasma generation electrode, a unit electrode is composed of a tabular ceramic material serving as a dielectric material and an electrically conductive film disposed in the inside of the ceramic material, a plurality of unit electrodes are layered at a constant spacing, the distance between the electrically conductive films disposed in the unit electrodes adjacent to each other is varied partly or the dielectric constant of the ceramic material constituting the unit electrode is varied partly, and plasmas having different intensities can be generated partly in the spaces.

Abstract: A system for purifying an exhaust gas includes a plasma unit and a catalyst unit. The plasma unit generates energetic plasma species which react with particulate matters and nitrogen oxides contained in the exhaust gas. The catalyst unit has a catalyst which reacts with the exhaust gas. The plasma unit is disposed upstream relative to the catalyst unit in a direction of flow of the exhaust gas and the system provides sequential purification for the particulate matters and the nitrogen oxides.

Abstract: In an exhaust gas purifying technique in which discharge is utilized, the invention provides a technique in which purification efficiency can be enhanced while an increase in electric power consumption is suppressed. A discharge mode including a discharge period and an undischarged period is adopted in a configuration in which a plasma process is performed to exhaust gas from a Diesel engine by generating the discharge in a plasma generator. A basic waveform periodically exists in a repeated manner in the discharge period, and the discharge is not performed in the undischarged period. An amplitude and/or a period of the basic waveform is controlled according to a load on the Diesel engine, a continuous iteration count of the basic waveform is controlled according to purification reaction efficiency in the plasma process, and the burst period is controlled according to an exhaust gas flow rate.

Abstract: A plasma reactor is provided with two or more plasma generating electrodes which are installed in series inside a gas passage in a casing, with each plasma generating electrode being electrically controlled independently. The surface area of the conductor on each unit electrode forming the plasma generating electrode installed on the upstream side of the gas passage is smaller than the surface area of the conductor on the unit electrode forming the plasma generating electrode installed on the downstream side of the gas passage. Plasma can be generated between each of the unit electrodes by supplying each of the plasma generating electrodes with independently controlled electric power. The plasma reactor can efficiently react specific components contained in the gas passing through the gas passage.

Abstract: An exhaust gas treating apparatus 1 includes: a case body 2 and a plasma producing means 3 capable of producing plasma inside the case body 2 and treats the substances to be treated contained in the exhaust gas by the plasma producing means 3. The plasma producing means 3 has one or more each of a pulse electrode 4 and a ground electrode 5 that are oppositely disposed in the case body 2 and has a pulse power source 6 capable of feeding a pulse current to the pulse electrode 4 by switching frequency and/or voltage for different values at predetermined time intervals. The substances to be treated contained in the exhaust gas can selectively be treated by switching frequency and/or voltage value for different values at predetermined time intervals so that plasma of a kind adequate for the substances to be treated contained in an exhaust gas is produced between the pulse electrode 4 and the ground electrode 5.

Abstract: A plasma generating electrode 1 of the present invention includes a plurality of unit electrodes 2 hierarchically layered at predetermined intervals, the unit electrodes 2 including a deficient unit electrode 2b in which a conductive film 4 has an absent portion and a normal unit electrode 2a in which the conductive film 4 does not have an absent portion. Spaces V formed between the unit electrodes 2 include a normal space Va formed so that the distance between conductive films 4 corresponds to the distance between the unit electrodes 2 and a deficient space Vb formed so that the distance between the conductive films 4 is greater than the distance between the conductive films 4 in the normal space Va. The plasma generating electrode 1 of the present invention can efficiently treat a plurality of predetermined components contained in a treatment target fluid by utilizing different types of plasma suitable for respective reactions by causing the treatment target fluid to flow only once.

Abstract: An exhaust gas purification system equipped, from an upstream side toward downstream side through which an exhaust gas flows, with a plasma reactor and a catalyst unit charged with a catalyst acting on NOx in the exhaust gas in this order, and equipped with a reducing agent supplying device to supply a reducing agent at an upstream side of the plasma reactor, wherein the catalyst has an NO2 adsorptive catalyst layer and an NO2 selective reduction catalyst layer contacting the NO2 adsorptive catalyst layer.

Abstract: A system for purifying an exhaust gas includes a plasma unit and a catalyst unit. The plasma unit generates energetic plasma species which react with particulate matters and nitrogen oxides contained in the exhaust gas. The catalyst unit has a catalyst which reacts with the exhaust gas. The plasma unit is disposed upstream relative to the catalyst unit in a direction of flow of the exhaust gas and the system provides sequential purification for the particulate matters and the nitrogen oxides.

Abstract: An exhaust gas purification system equipped, from an upstream side toward downstream side through which an exhaust gas flows, with a plasma reactor and a catalyst unit charged with a catalyst acting on NOx in the exhaust gas in this order, and equipped with a reducing agent supplying device to supply a reducing agent at an upstream side of the plasma reactor, wherein the catalyst has an NO2 adsorptive catalyst layer and an NO2 selective reduction catalyst layer contacting the NO2 adsorptive catalyst layer.

Abstract: An exhaust gas purification system that is equipped, from an upstream side toward downstream side through which an exhaust gas flows, with a plasma reactor and a NOx selective reduction catalyst unit having a NOx selective reduction catalyst layer acting on the exhaust gas, and which system provides a reducing agent adding means adding a reducing agent to the exhaust gas at an upstream side of the plasma reactor, wherein the NOx selective reduction catalyst layer comprises nickel and a NOx selective reduction catalyst or wherein the NOx selective reduction catalyst layer contains &ggr;-alumina that supports magnesium or wherein the NOx selective reduction catalyst unit comprises a first purification unit where an exhaust gas via the plasma reactor is introduced, and a second purification unit where an exhaust gas via the first purification unit is introduced.