摘要:
In the present invention, the exhaust gas from the engine is divided into a first and a second branch exhaust passages after it passes through a three-way reducing and oxidizing catalyst, and the two branch exhaust passages merge into an exhaust gas outlet passage. In the first branch exhaust passage, an oxidizing catalyst is disposed, and in the exhaust gas outlet passage, a denitrating and oxidizing catalyst is disposed. NO.sub.x in the exhaust gas from the engine is all converted to N.sub.2 and NH.sub.3 by the three-way reducing and oxidizing catalyst and a part of the NH.sub.3 generated by the three-way catalyst flows into the first branch exhaust passage and is converted to NO.sub.x again by the oxidizing catalyst. The amount of NO.sub.x produced by the oxidizing catalyst and the amount of NO.sub.x flowing through the second branch exhaust passage is determined by the flow distribution ratio of the first and the second branch exhaust passages. In this invention, the flow ratio is determined in such a manner that the amount of the NO.sub.x produced by the oxidizing catalyst and the amount of the NH.sub.3 passing through the second branch exhaust passage are stoichiometric to produce N.sub.2 and H.sub.2 O. Therefore, when these exhaust gases flow into the denitrating and oxidizing catalyst after they mix with each other in the exhaust gas outlet passage, all the NO.sub.x and the NH.sub.3 are converted to N.sub.2 and H.sub.2 O by the denitrating and oxidizing catalyst without producing any surplus NO.sub.x or NH.sub.3.
摘要:
In the present invention, a NO.sub.x absorbent is used for removing the NO.sub.x in the exhaust gas. The NO.sub.x absorbent absorbs NO.sub.x in the exhaust gas when the air-fuel ratio of the exhaust gas is lean, and releases the absorbed NO.sub.x and reduces it to nitrogen when the air-fuel ratio of the exhaust gas is rich or stoichiometric. To prevent the NO.sub.x absorbent from being saturated with the absorbed NO.sub.x, the NO.sub.x absorbent must be regenerated periodically by causing the NO.sub.x in the absorbent to be released and reduced. However, it is found that when the regenerating process by supplying a rich air-fuel ratio exhaust gas to the NO.sub.x absorbent is carried out at high NO.sub.x absorbent temperature, a part of NO.sub.x flows out from the NO.sub.x absorbent at the beginning of the regenerating process without being reduced. In the present invention, this outflow of NO.sub.x is suppressed by, for example, carrying out the regenerating process only when the temperature of the NO.sub.x absorbent is lowered to a predetermined temperature. This predetermined temperature is set low enough to ensure that the amount of the outflow of NO.sub.x is minimized.
摘要:
The exhaust gas purification device according to the present invention utilizes two NOx absorbents in order to remove NOx from the exhaust gas of an engine operated at a lean air-fuel ratio. The NOx absorbents are disposed, in series, in the exhaust passage of the engine and a nozzle for supplying a reducing agent is disposed in the exhaust passage at a position between the two NOx absorbents. Further, the device includes switching valves for changing the direction of the exhaust gas flow in the exhaust gas passage. When the switching valves are set to direct the exhaust gas flow to one direction, the exhaust gas first flows through one of the NOx absorbents (first NOx absorbent), and after passing through the first NOx absorbent, the reducing agent is supplied to the exhaust gas before it flows into the other NOx absorbent (second NOx absorbent). Thus, the first NOx absorbent absorbs NOx in the exhaust gas, and the NOx absorbed by the second NOabsorbent is released from the second NOx absorbent. When the switching valves are switched, the exhaust gas flows in the opposite direction, and flows through the second NOx absorbent and the first NOx absorbent in this order. In this case, the second NOx absorbent absorbs NOx in the exhaust gas, and the NOx absorbed by the first NOx absorbent is released and reduced to N2. Therefore, by reversing the direction of the exhaust gas periodically, the absorbing operation of NOx and releasing/reducing operation of NOx are performed by two NOx absorbents alternately. Thus, it becomes possible to remove NOx in the exhaust gas continuously while the NOx absorbents are prevented from being saturated by the absorbed NOx.
摘要:
The method for purifying combustion exhaust gas according to the present invention utilizes a NH.sub.3 decomposing catalyst. The NH.sub.3 decomposing catalyst in the present invention is capable of converting substantially all of the NH.sub.3 in the combustion exhaust gas to N.sub.2 when the air-fuel ratio of the exhaust gas is lean and the temperature of the catalyst is within a predetermined optimum temperature range. Further, when the exhaust gas contains NO.sub.x in addition to NH.sub.3, the NH.sub.3 decomposing catalyst is capable of reducing the NO.sub.x in the optimum temperature range even though the air-fuel ratio of the exhaust gas is lean. In the present invention, the conditions of the exhaust gas containing NO.sub.x are adjusted before it is fed to the NH.sub.3 decomposing catalyst in such a manner that the temperature of the exhaust gas is within the optimum temperature range and the air-fuel ratio of the exhaust gas is lean. Further, NH.sub.3 is added to the exhaust gas before it is fed to the NH.sub.3 decomposing catalyst. Therefore, a lean air-fuel ratio exhaust gas, at a temperature within the optimum temperature range, which contains both the NO.sub.x and NH.sub.3 is fed to the NH.sub.3 decomposing catalyst, and the NO.sub.x, as well as the NH.sub.3, in the exhaust gas is completely resolved by the NH.sub.3 decomposing catalyst.
摘要:
An exhaust gas purifying catalyst, for reducing nitrogen oxides and ammonia in an exhaust gas of an internal combustion engine, in an oxidizing atmosphere, is provided. The exhaust gas purifying catalyst comprises a first catalyst having zeolite carrying platinum and copper thereon. Preferably, the exhaust gas purifying catalyst further comprises a second catalyst having zeolite carrying copper thereon. Preferably, the second catalyst is arranged upstream of the first catalyst, with respect to the exhaust gas flow.
摘要:
A device for purifying the exhaust gas of an engine having a plurality of cylinders divided into first and second cylinder groups, the first and the second cylinder groups being connected to first and second exhaust passage, respectively, and performing a lean operation, comprises an NH.sub.3 synthesizing catalyst arranged in the first exhaust passage, and an exhaust gas purifying catalyst arranged in an interconnecting passage, which interconnects the first passage downstream of the NH.sub.3 synthesizing catalyst and the second exhaust passage, for purifying the inflowing NO.sub.X and NH.sub.3. An additional engine performing a rich operation is provided and the exhaust gas thereof is fed to the first exhaust gas passage upstream of the NH.sub.3 synthesizing catalyst to make the exhaust gas air-fuel ratio of the exhaust gas flowing into the NH.sub.3 synthesizing catalyst rich, to thereby synthesize NH.sub.3 therein. An amount of NH.sub.3 or NO.sub.X flowing into the exhaust gas purifying catalyst is obtained, and the additional engine is controlled in accordance with the obtained NH.sub.3 or NO.sub.X amount to control the amount of the reducing agent flowing to the exhaust gas purifying catalyst.
摘要:
An engine (1) has first and second cylinder groups (1a) and (1b). The first cylinder group (1a) is connected to a three way (TW) catalyst (8a). The second group (1b) and the TW catalyst (8a) are connected, via an interconnecting duct (13) to an NH.sub.3 adsorbing and oxidizing (NH.sub.3 -AO) catalyst (14a). The first group (1a) performs the rich operation, and the second group (1b) performs the lean operation. In the TW catalyst (8a), NO.sub.x exhausted from the first group (1a) is converted to NH.sub.3, and the NH.sub.3 reduces the NO.sub.x exhausted from the second group (1b) in the NH.sub.3 -AO catalyst (14a). A NO.sub.x occluding and reducing (NO.sub.x -OR) catalyst (11a) is arranged in the exhaust passage between the second group (1b) and the interconnecting duct (13), to thereby suppress the NO.sub.x amount flowing into the NH.sub.3 -AO catalyst (14a).
摘要:
To provide an exhaust gas purifying system for an internal combustion engine capable of executing an optimal regenerative operation by predicting a temperature of an absorbent based on running state information.There are predicted the amount of nitrogen oxides (NO.sub.x) to be absorbed by an absorbent 125 incorporated in a catalyst 124 and the temperature of the absorbent, based on the running state information obtained from a car navigation system 141 or traffic information service receiver 142, and the regenerative operation schedule is determined based on the prediction. Thus, the regenerative operation is conducted at the timing where NO.sub.x has been duly absorbed by the absorbent and the absorbent temperature is lower than a predetermined temperature, so that the leakage of NO.sub.x into the exterior of a vehicle can be restrained.
摘要:
An apparatus for controlling auxiliary equipment driven by an internal combustion engine, which can suppress the deterioration of a specific fuel consumption by controlling the auxiliary equipment based on running environment information provided from a car navigation system or the like. Namely, this apparatus predicts the future maximum output of the internal combustion engine and a running load thereof according to running environment information and vehicle information. Further, if the maximum output is larger than the running load, the auxiliary equipment (for example, a light and an air conditioner) are directly driven by the internal combustion engine. Moreover, surplus energy is stored in an energy storing device. When the maximum output is nearly equal to the running load and that the specific fuel consumption is deteriorated when driving the auxiliary equipments, they are driven by using the energy stored in the energy storing device. Consequently, the deterioration of the fuel consumption ratio due to the operations of the accessories is suppressed.
摘要:
An exhaust manifold of an engine is connected to a three way (TW) catalyst, and the TW catalyst is connected to an NH.sub.3 adsorbing and oxidizing (NH.sub.3 -AO) catalyst, such as the Cu-zeolite catalyst. The engine performs the lean and the rich operations alternately and repeatedly. When the engine performs the rich operation, the TW catalyst synthesizes NH.sub.3 from NO.sub.x in the inflowing exhaust gas, and the NH.sub.3 is then adsorbed in the NH.sub.3 -AO catalyst. Next, when the engine performs the lean operation, NO.sub.x passes through the TW catalyst, and the adsorbed NH.sub.3 is desorbed and reduces the inflowing NO.sub.x. When the rich operation is in process, or is to be started, the exhaust gas temperature flowing into the NH.sub.3 -AO catalyst is detected. If the temperature is equal to or higher than the upper threshold representing the rich endurance temperature, the lean or the stoichiometric operation is performed.