摘要:
The present invention relates to a method of removing nitrogen oxides from the exhaust gas of a lean-burn internal combustion engine by selective catalytic reduction (SCR) using ammonia. The exhaust gas is routed first over a platinum-containing pre-catalyst and then over an SCR catalyst. The ammonia needed for the selective catalytic reduction is added to the exhaust gas upstream of the pre-catalyst at an exhaust-gas temperature below 250° C., while it is supplied to the exhaust gas between the pre-catalyst and the SCR catalyst at an exhaust gas temperature above 150° C. By adopting this procedure, a very large temperature range for the selective catalytic reduction with high nitrogen conversion rates is obtained.
摘要:
The present invention relates to an exhaust-gas purification system for the selective catalytic reduction of nitrogen oxides. The system includes at least one catalyst having catalytically active components for the selective catalytic reduction (SCR components). An NOx storage catalyst (5) is arranged upstream of the SCR catalyst (3) in the exhaust-gas purification system. For performing the selective catalytic reduction, metering means (8) for supplying a compound decomposable into ammonia is provided between the NOx storage catalyst and the SCR catalyst (3). At low exhaust-gas temperatures, the NOx storage catalyst (5) adsorbs the nitrogen oxides contained in the exhaust gas and desorbs them only at rising exhaust-gas temperatures, so that they can afterwards be converted by the SCR catalyst (3) which is active then. This results in an altogether improved conversion rate for the nitrogen oxides.
摘要:
The present invention relates to a method of removing nitrogen oxides from the exhaust gas of a lean-burn internal combustion engine by selective catalytic reduction (SCR) using ammonia. The exhaust gas is routed first over a platinum-containing pre-catalyst and then over an SCR catalyst. The ammonia needed for the selective catalytic reduction is added to the exhaust gas upstream of the pre-catalyst at an exhaust-gas temperature below 250° C., while it is supplied to the exhaust gas between the pre-catalyst and the SCR catalyst at an exhaust gas temperature above 150° C. By adopting this procedure, a very large temperature range for the selective catalytic reduction with high nitrogen conversion rates is obtained.
摘要:
A power supply system having a multiphase matrix converter and a method for operating the system are proposed. The converter has a plurality of input and output terminals and a plurality of sub-converters. The input terminals are respectively connected to the output terminals via bidirectional switches of the sub-converters. A circuit has at latest one DC source, an inverter connected in series with the DC source to generator a first alternating voltage, and an HF transformer connected in series with the inverter and connected to each of the input terminals. The HF transformer transforms the first alternating voltage up into a second alternating voltage and changes the frequency of the second alternating voltage by a multiple as compared with frequency of the first alternating voltage. A control unit activates the bidirectional switches as a function of the second alternating voltage present on the output of the HF transformer.
摘要:
A portable spray apparatus (1) is provided to selectively discharge liquid spray medium and solid dust medium with a blower airflow (7) generated by a blower (6). An adaptor (8) is provided which has at least a channel section (9) of a liquids channel (10) for the liquid spray medium and a channel section (11) of a solids channel (12) for the solid dust medium. The adaptor (8) is releasably connected to a supply vessel (4). The liquids channel (10) and the solids channel (12) open into the blower airflow (7). Various built-in positions of the supply vessel (4) and of the adaptor (8) are freely selectable relative to each other and to the blower unit (3) by the operator. In one built-in position, the liquids channel (10) is connected via its channel section (9) to an interior space (13) of the supply vessel (4) and, in another built-in position, the solids channel (12) is connected to this interior space (13) via the channel section (11) thereof.
摘要:
A portable spray apparatus (1) is provided to selectively discharge liquid spray medium and solid dust medium with a blower airflow (7) generated by a blower (6). An adaptor (8) is provided which has at least a channel section (9) of a liquids channel (10) for the liquid spray medium and a channel section (11) of a solids channel (12) for the solid dust medium. The adaptor (8) is releasably connected to a supply vessel (4). The liquids channel (10) and the solids channel (12) open into the blower airflow (7). Various built-in positions of the supply vessel (4) and of the adaptor (8) are freely selectable relative to each other and to the blower unit (3) by the operator. In one built-in position, the liquids channel (10) is connected via its channel section (9) to an interior space (13) of the supply vessel (4) and, in another built-in position, the solids channel (12) is connected to this interior space (13) via the channel section (11) thereof.