Abstract:
An exhaust purification system of an internal combustion engine provided with an NOx storage reduction catalyst an oxidation catalyst which is arranged downstream of the NOx storage reduction catalyst an exhaust gas tank which is connected to the engine exhaust passage between the NOx storage reduction catalyst and the oxidation catalyst, and a switching valve which closes the engine exhaust passage toward the oxidation catalyst and makes the exhaust gas flow into the tank. When making the air-fuel ratio of the exhaust gas which flows into the NOx storage reduction catalyst rich, the engine exhaust passage toward the oxidation catalyst is shut and the flow path is switched so that the exhaust gas flows to the tank to thereby store the exhaust gas in the tank.
Abstract:
An exhaust purification system of an internal combustion engine is provided with a hydrocarbon feed valve arranged in an engine exhaust passage and an exhaust purification catalyst for causing NOX contained in exhaust gas and reformed hydrocarbons to react. The exhaust purification catalyst reduces NOX if a concentration of inflowing hydrocarbons vibrates within a predetermined range of amplitude and within a predetermined range of period and increases the amount of storage of NOX if the vibration period of the concentration of hydrocarbons longer is than a predetermined range. When hydrocarbons are being fed from the hydrocarbon feed valve within the predetermined range of amplitude and the predetermined range of period, if the amount of adsorption of hydrocarbons in the exhaust purification catalyst exceeds a predetermined judgment value of the adsorption amount, at least one of reducing amount of feed of hydrocarbons and lengthening feed interval of hydrocarbons is performed.
Abstract:
In an internal combustion engine, inside an engine exhaust passage, a hydrocarbon feed valve (15) and an exhaust purification catalyst (13) are arranged. A first hydrocarbon feed method which injections hydrocarbons from the hydrocarbon feed valve (15) by predetermined feed intervals (ΔT) so that the air-fuel ratio of the exhaust gas falls to the demanded minimum air-fuel ratio (X) to thereby remove the NOx contained in the exhaust gas and a second hydrocarbon feed method which lowers the feed amount of hydrocarbons from the hydrocarbon feed valve (15) and feeds fuel to the combustion chambers (2) during a second half of the expansion stroke or the exhaust stroke are selectively used.
Abstract:
Inside of an engine exhaust passage, in order from an upstream side, a hydrocarbon feed valve oxidation catalyst exhaust purification catalyst, and NOX selective reduction catalyst are arranged. By lowering the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst by a predetermined period while maintaining it lean, the NOx is reduced in the exhaust purification catalyst and the NOX which was not reduced at the exhaust purification catalyst is reduced by the ammonia which is adsorbed at the NOX selective reduction catalyst. The air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst is sometimes switched from lean to rich. At this time, the ammonia which was generated at the exhaust purification catalyst is adsorbed at the NOX selective reduction catalyst.
Abstract:
An object of the present invention is to prevent an excessive temperature rise of a precatalyst in the case where the precatalyst is provided in the exhaust passage upstream of an exhaust gas purification apparatus and has a heat capacity smaller than that of the exhaust gas purification apparatus, and reducing agent is added from a reducing agent addition valve toward an upstream end surface of the precatalyst. According to the present invention, the reducing agent addition valve is located in such a way that the reducing agent added through it reaches the precatalyst in a liquid state. In the case where the level of activity of the precatalyst is higher than a specific level at the time when the addition of reducing agent through the reducing agent addition valve is performed so as to supply the reducing agent to the precatalyst and the exhaust gas purification apparatus, the reducing agent is added more intensively than in the case where the level of activity of the precatalyst is not higher than the specific level.
Abstract:
An exhaust gas control apparatus includes an oxidation catalyst, a compact oxidation catalyst having a smaller cross section than that of an engine exhaust passage, a fuel supply valve, a glow plug, and an electronic control unit. The control modes for the exhaust gas control apparatus include a first control mode where the fuel is supplied from the fuel supply valve, heated by the glow plug, and ignited, a second control mode where the fuel is supplied from the fuel supply valve, and heated by the glow plug but is not ignited, and a third control mode where the fuel is supplied from the fuel supply valve and the glow plug does not provide heating. The electronic control unit selects the first or third control mode in the operation region where ignition is possible, and selects the second or third control mode in the operation region where ignition is not possible.
Abstract:
In an exhaust gas purification apparatus for an internal combustion engine, reducing agent is diffused and the exhaust resistance is made small. The apparatus includes a reducing agent addition valve that injects reducing agent, a reducing agent addition valve mount portion that has a space in which the reducing agent addition valve injects the reducing agent outside a stream of exhaust gas flowing in an exhaust passage of an internal combustion engine and on which the reducing agent addition valve is mounted, and an impingement portion that is provided in the reducing agent addition valve mount portion and on which the reducing agent injected through the reducing agent addition valve impinges, wherein the direction of injection of the reducing agent from the reducing agent addition valve is oriented toward the impingement portion, and toward downstream of the reducing agent addition valve with respect to the exhaust gas flow.
Abstract:
A technique is provided that enables reducer concentrations in exhaust gas flowing into an exhaust purification device on the upstream side and an exhaust purification device on the downstream side provided to an exhaust pipe in series to be controlled separately with a simple configuration. Included are the two exhaust purification devices provided to an exhaust passage in series, a bypass passage that bypasses the exhaust purification device on the upstream side, an exhaust control valve provided to the bypass passage, and reducer supply means provided on the upstream side of a branch portion. A reducer is supplied intermittently from the reducer supply means to periodically change the reducer concentration in the exhaust gas, and the exhaust control valve is opened or closed periodically at a predetermined timing with respect to the change in the reducer concentration. Accordingly, the supplied reducer is distributed to be introduced to the exhaust purification device on the upstream side or to be introduced to the exhaust purification device on the downstream side via the bypass passage.
Abstract:
A water hammerless valve includes a pneumatically-operated valve having a valve disc for opening and closing a fluid channel by moving upward and downward through a pneumatic actuator operation, and a limiting mechanism for interfering with upward movement of the valve disc when the water hammer occurs. The limiting mechanism includes a stepping motor including a rotation shaft fixed on the upper actuator; a vertical movement component connected to the rotation shaft for moving upward and downward via rotation of the rotation shaft; a lower detecting component for detecting the fact that the vertical movement component contacts the upper end of a stem when the lower detecting component moves downward; and a control device for rotating the stepping motor, for controlling the air supply, and for transmitting a stop signal to the stepping motor when the lower end of the lower detecting component detects the fact.
Abstract:
An exhaust gas processing apparatus (26) has a bypass passage (31a) arranged in parallel with exhaust turbine (24b), an actuator (33) for opening/closing a bypass valve (32) to open/close the bypass passage, a fuel supplying valve (29) for supplying fuel to an exhaust passage (22a) upstream of a branch portion between the exhaust and bypass passages, a glow plug (30) for igniting the fuel supplied from the fuel valve, and an ECU (13) including a processing mode selecting unit (13k) for selecting a first exhaust gas processing mode for igniting the fuel to introduce the ignited fuel from the bypass passage to an exhaust emission purifier (25), or a second exhaust gas processing mode for introducing the fuel supplied to the exhaust passage through an exhaust turbine (24b) to the exhaust emission purifier without igniting the fuel, based upon whether or not there is a flame failure of the fuel.