JP2007046599A - Exhaust manifold assembly body for internal combustion engine and exhaust gas controller and control method for internal combustion engine equipped with assembly body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust manifold assembly body at low cost, an exhaust gas controller, and an exhaust gas control method for an internal combustion engine for adjusting temperature of exhaust gas to satisfy demand of temperature and cost restriction conditions being contradictory such as suppression of too early prescription and speedy achievement of light-off of a catalyst device. <P>SOLUTION: An exhaust manifold for the internal combustion engine 10 is provided with two exhaust gas flow paths 12, 13 prescribed in it. The first flow path 12 directs exhaust gas without appreciable cooling effect to a three-way catalyst 16 located downstream and the second flow path 13 includes water cooling for the exhaust gas passing therethrough using a coolant drawn from a main engine cooling circuit. One or more valves 15 are used to control the proportion of flow through the first and second flow paths 12, 13 so as to regulate the temperature of the exhaust gas entering the three-way catalyst 16. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an internal combustion engine, and more specifically, an exhaust manifold assembly for adjusting exhaust gas flowing to a downstream exhaust gas control device, an exhaust gas control device for an internal combustion engine equipped with the assembly, and the same It relates to a control method.

Lean burn gasoline engines are one technique that can be used to reduce CO ₂ emissions. A NOx trap is required as part of the exhaust emission control system of these engines in order to meet the NOx emission control requirements of the exhaust pipe. Current NOx trap technology is temperature sensitive, that is, the NOx trap capability is degraded by temperatures above about 650 ° C. resulting in thermal aging of the trap. In addition, NOx trap efficiency is highly dependent on trap temperature, and trap temperature is ideally maintained within a specified range relative to the target temperature, which depends on the NOx trap design, to obtain optimal NOx trap capability. It must be done. This predetermined range may be as narrow as plus or minus 25 degrees from the target temperature.

  If sulfur deposits accumulate in the NOx trap, they must be removed by a process known as “desulfurization”. In “desulfurization”, the temperature of the NOx trap must be increased to 600 ° C. or higher so that the exhaust gas control device can promote desulfurization.

  It is also known to place an engine catalyst close to the engine outlet in order to reduce the time required to “light off” the catalyst. Such catalysts are well known as close coupled catalysts because they are usually coupled directly to the engine exhaust manifold.

  Such proximity catalysts are also subject to high temperature aging, which can be mitigated by reducing the temperature of the incoming gas. However, in order to ensure a reduction in exhaust pipe emissions, the reduction in exhaust gas temperature should not be as rapid as possible, at the expense of achieving “light off” of the catalyst. Catalyst light-off is achieved when the catalyst reaches the operating temperature from a cold start, where an active reduction of emissions begins.

  These conflicting temperature requirements and cost constraints require a low cost method to adjust the exhaust gas temperature without compromising catalyst light-off.

  It is an object of the present invention to provide an improved exhaust manifold assembly for an internal combustion engine (engine), an exhaust gas control device using the same, and a method thereof.

  According to the first aspect of the present invention, an inlet into which exhaust gas from an internal combustion engine (engine) flows during use, an exhaust port through which exhaust gas flows out during use, and the exhaust gas is moved from the inlet to the exhaust port. The first exhaust gas flow path for controlling the flow rate, the second exhaust gas flow path for moving the exhaust gas from the inlet to the discharge port, and the flow rate of the exhaust gas flowing through the first exhaust gas flow path and the second exhaust gas flow path An exhaust manifold assembly having valve means for performing exhaust gas flowing through the first exhaust gas passage through the exhaust manifold assembly with minimal cooling and exhaust flowing through the second exhaust gas passage An exhaust manifold assembly is provided in which the gas is actively cooled from an exhaust gas cooler so that the temperature of the exhaust gas exiting the exhaust manifold assembly can be adjusted.

  The valve means may operate such that all or most of the exhaust gas from the internal combustion engine (engine) passes through the first exhaust gas flow path when the internal combustion engine (engine) is cold started.

  The valve means may be actuated so that all or most of the exhaust gas from the engine passes through the first exhaust gas flow path at least when the exhaust gas temperature is below the first predetermined temperature.

  The valve means operates so that at least part of the exhaust gas passes through the second exhaust gas flow path when the exhaust gas temperature exceeds the second predetermined temperature.

  The valve means may be operable to change the ratio of exhaust gas flowing through the first exhaust gas flow path and the second exhaust gas flow path to adjust the temperature of the exhaust gas exiting the exhaust manifold assembly.

  The exhaust gas can be adjusted to maintain the temperature of the exhaust gas exiting the exhaust manifold assembly within a predetermined temperature range.

  The valve means may be a single control valve placed in place to regulate the flow rate of exhaust gas through the first exhaust gas flow path.

  A valve means may be placed in the vicinity of the outlet to selectively limit the flow of exhaust gas exiting the first exhaust gas flow path.

  Alternatively, the valve means may be a single control valve placed in place to regulate the exhaust gas flow rate through the second exhaust gas flow path.

  The valve means can be placed in the vicinity of the outlet to selectively limit the flow rate of the exhaust gas exiting the second exhaust gas flow path.

  As yet another alternative, the valve means may be a single control valve in place to simultaneously adjust the flow rate of exhaust gas through the first exhaust gas flow path and the second exhaust gas flow path. .

  In this case, the valve means can be placed in the vicinity of the discharge port to selectively change the flow rate of the exhaust gas exiting from the first exhaust gas flow path and the second exhaust gas flow path.

  The exhaust gas cooler can use the refrigerant taken out from the main cooling device of the engine.

  The exhaust manifold assembly surrounds at least one inner exhaust conduit defining a first exhaust passage and the inner exhaust conduit and is spaced from the inner exhaust conduit to define a second exhaust passage. A first housing disposed at a distance from the first housing so as to define a gap surrounding the first housing and a passage through which the refrigerant for forming the exhaust gas cooler passes. 2 housings.

  Each of the inner exhaust conduits is connected to an exhaust from the engine by a flange plate.

  The flange plate (which may be single or multiple) may have a tubular sleeve extending therefrom to engage the end of the inner exhaust gas conduit.

  The exhaust manifold may have a single flange plate and as many tubular sleeves as there are cylinders in the engine to which the exhaust manifold assembly is coupled.

  Each of the tubular sleeves may have one or more openings therein for providing an inlet to the second exhaust gas flow path.

  Alternatively, each of the tubular sleeves 1 for cooperating with one or more corresponding openings in the end of the inner exhaust gas conduit with which it engages to provide an inlet to the second exhaust gas flow path. There can be more than one opening in it.

  The manifold assembly may also have a number of inner exhaust gas conduits that form the first exhaust gas flow path.

  The inner exhaust conduit may flow exhaust from the engine to a junction where separate inner exhaust conduits merge to form a single conduit extending to the outlet.

  The first exhaust gas flow path can be formed by one exhaust gas conduit, the control means is a control valve placed at the outlet end of the exhaust gas conduit, and the second exhaust gas flow path is the exhaust gas conduit Formed by a first cooling conduit connecting the control valve to the inlet of the exhaust gas cooler and a second cooling conduit connecting from the outlet of the exhaust gas cooler to the control valve, the control valve being a first exhaust gas flow path And operating to regulate the flow rate of the exhaust gas through the second exhaust gas flow path.

  There may be several exhaust gas conduits that allow the exhaust gas to flow independently from the engine to a junction where each conduit merges to form a single conduit that extends to the control valve therein.

  The control valve passes through the first exhaust gas flow path only from the first position where all exhaust gas flows from the inlet to the exhaust port, and passes through the second exhaust gas flow path from the inlet to the exhaust port. May be movable to a second position through which the flows.

  When the control valve is located between the first position and the second position, a part of the exhaust gas can flow through the first exhaust gas flow path, and a part of the exhaust gas can flow through the second exhaust gas flow path.

  The position of the control valve between the first position and the second position can be changed to adjust the temperature of the exhaust gas exiting the exhaust manifold through the exhaust port.

  When the control valve is in the first position, the flow of exhaust gas through the second cooling conduit may be substantially obstructed.

  Even when the control valve is in the first position, a slight leakage of exhaust gas through the control valve may be allowed to cool the control valve.

  According to a second aspect of the present invention, there is provided an exhaust manifold assembly according to the first aspect of the present invention, and an exhaust gas control device for an engine having a catalyst device connected to an exhaust port from the exhaust manifold assembly. Provided.

  The catalytic device can be a three-way catalyst.

  The exhaust gas control device may further comprise a lean NOx trap placed downstream of the three way catalyst.

  The three-way catalyst and the lean NOx trap can be mounted in a common canister that is directly connected to the outlet from the exhaust manifold assembly.

  The exhaust gas control device may further include an electronic control device and an exhaust temperature sensor operably coupled to the electronic control device to provide a signal representative of the exhaust gas temperature downstream of the exhaust manifold.

  The valve means can be a control valve and the position of the control valve can be controlled by an electronic controller.

  The position of the control valve can be controlled by the electronic controller in response to one of the signals received from the exhaust temperature sensor and the exhaust temperature model.

  The electronic control unit may operate to move the control valve to a position where the exhaust gas flows simply or primarily through the first exhaust gas flow path when the detected exhaust gas temperature falls below the first predetermined temperature. .

  The first predetermined temperature may be a light-off temperature of a three-way catalyst coupled to the exhaust manifold.

  The three-way catalyst is connected to an exhaust port from the exhaust manifold, the lean NOx trap is placed downstream of the three-way catalyst, and the electronic control unit keeps the temperature of the exhaust gas in the lean NOx trap within a predetermined temperature range. Can be operated to control the position of the control valve.

  The lower limit of the boundary is determined by the lower temperature limit where the lean NOx trap does not operate efficiently below that temperature, and the upper temperature limit at which premature aging occurs in the lean NOx trap above that temperature. The upper edge of the boundary can be determined.

  The predetermined temperature range may be a temperature range at which the lean NOx trap operates at maximum efficiency.

  The electronic controller may operate to allow the exhaust gas temperature to exceed the upper temperature limit when sulfur needs to be removed from the lean NOx trap.

  According to a third aspect of the present invention, an exhaust manifold assembly according to the first aspect of the present invention, a three-way catalyst coupled to an outlet from the exhaust manifold assembly, and a downstream of the three-way catalyst. In the control method of the exhaust gas control apparatus provided with the lean NOx trap, the exhaust gas temperature corresponding to the light-off temperature of the three-way catalyst is reached in order to quickly light-off the three-way catalyst after starting the engine. Until now, a method is provided that includes providing a flow path through the first exhaust gas flow path for all or most of the exhaust gas.

  The method changes the flow rate of exhaust gas through the first exhaust gas flow path and the second exhaust gas flow path so that the exhaust gas temperature in the lean NOx trap remains within a range where the lean NOx trap operates at maximum efficiency. May further include a step of controlling the temperature of the exhaust gas passing through the three-way catalyst and the lean NOx trap.

  When the exhaust gas temperature approaches the upper temperature limit above which premature aging of one of the three-way catalyst and lean NOx trap occurs, all or most of the exhaust gas flows into the second exhaust gas stream. There may be a further step of providing a flow path through the path.

  The method may further comprise the step of allowing the exhaust gas temperature to deviate above the upper temperature limit when sulfur needs to be removed from the lean NOx trap.

  Referring specifically to FIG. 1, an exhaust gas control device for an internal combustion engine (engine) is shown. In this example, the engine is a lean burn engine 10.

  The exhaust gas control device includes an exhaust manifold assembly that defines the first exhaust gas flow path 12 and the second exhaust gas flow path 13, and a three-way catalyst that is disposed downstream of the exhaust manifold assembly to receive the exhaust gas from the exhaust manifold assembly. 16, illustrated by a lean NOx trap 17 downstream of the three-way catalyst to receive exhaust gas from the three-way catalyst 16, valve means 15 for adjusting the flow rate through the exhaust manifold assembly, and a temperature sensor 20. An electronic control unit 5 is provided for controlling the operation of the valve means 15 based on the exhaust gas temperature measured at at least one location.

  Alternatively, the control may be based on the modeled exhaust gas temperature, that is, a temperature model (a calculation formula or a lookup table set using the temperature model).

  A silencer 18 is placed downstream of the lean NOx trap to reduce noise emitted from the exhaust pipe 19 of the exhaust system that forms the majority of the exhaust gas control device.

  The exhaust manifold assembly has an inlet through which exhaust gas from the engine flows and an outlet through which exhaust gas flows from the three-way catalyst 16. The valve means 15 is used for adjusting the flow rate of exhaust gas passing through the first exhaust gas passage 12 and the second exhaust gas passage 13.

  The valve means 15 is shown near the end of the first exhaust gas flow path 12, but it is located at a position near the end of the second exhaust gas flow path 13 or at the junction of the two flow paths. It will be appreciated that it may be placed in, or may be placed in both exhaust gas passages 12,13. Preferably, whatever valve means is used, the valve means is placed near the outlet from the exhaust manifold assembly in order to minimize the temperature at which the valve operates.

  Exhaust gas flowing through the first exhaust gas flow path 12 flows without being cooled so much that the highest possible exhaust gas temperature is moved from the exhaust manifold assembly to the exhaust outlet. That is, nothing is intended to cool the exhaust gas flowing through the first flow path, and minimal cooling of the exhaust gas occurs due to natural heat conduction and radiation loss.

  On the contrary, the exhaust gas flowing through or passing through the second exhaust gas passage 13 is exposed to positive cooling from the exhaust gas cooler 14 and the exhaust gas entering the second exhaust gas passage 13, There is a large temperature deviation between the exhaust gas exiting the two exhaust gas passages 13.

  The exhaust gas cooler 14 may take various forms, but in any case, a liquid refrigerant is used to cool the exhaust gas passing through the second exhaust gas flow path 13.

  Preferably, the refrigerant is drawn from a main cooling circuit (not shown) of the engine 10 and then returned to the main cooling circuit. This is because the exhaust gas cooler 14 can recover some heat from the exhaust gas and return it to the main cooling circuit. This is advantageous when promoting engine warm-up after starting the engine at low temperatures, thereby reducing emissions during engine warm-up, reducing emissions during warm-up, and passenger compartment heaters. Improve ability. However, it will be understood that an independent refrigerant supply circuit having a radiator for dissipating the heat absorbed from the exhaust gas and a pump for circulating the refrigerant can also be used if desired.

  The three way catalyst 16 can be placed at a short distance downstream of the exhaust manifold, but is preferably connected directly to the exhaust outlet from the exhaust manifold. That is, the three-way catalyst 16 is preferably a proximity catalyst.

  Similarly, the lean NOx trap may be an independent device placed downstream of the three-way catalyst 16, but by utilizing the exhaust manifold assembly according to the present invention, the three-way catalyst 16 and the lean NOx trap 17 are exhaust manifold. Advantageously, it can be mounted in a common canister directly coupled to the outlet. This is because such an arrangement can be manufactured at a lower price than a vehicle with two canisters and can be more easily arranged in the vehicle. In such an arrangement, the common canister arrangement houses a three way catalyst brick at the inlet end of the canister and the NOx trap is placed downstream of the three way catalyst brick and near the outlet of the common canister. I will.

  Although a single temperature sensor 20 is shown at the inlet of the NOx trap 17, several temperature sensors exit the exhaust manifold, exit the three way catalyst 16, enter the NOx trap 17, and the NOx trap. It may also be used to provide a signal indicating the temperature of the exhaust gas at various locations, such as exiting 17. Alternatively, the temperature of the exhaust gas can be calculated using a pre-designed model. However, effective control of the valve means 15 is obtained when at least one signal indicating the approximate temperature of the exhaust gas leaving the three-way catalyst 16, ie the exhaust gas entering the NOx trap 17, is supplied to the electronic control unit 5. obtain.

  The operation of the exhaust gas control device is as follows.

  The main requirement for starting the engine is that it is not important until the three-way catalyst 16 is lighted off as soon as possible and the engine 10 can be operated in lean mode, but the NOx trap 17 Is turned off. A lean burn engine typically requires about 3 minutes of operation until it is warm enough to operate lean.

  Accordingly, during this operating phase, the electronic control unit 5 is configured to provide the valve means so that the valve means 15 is fully opened so that the majority of the exhaust gas enters the exhaust manifold assembly through the first exhaust gas flow path 12. 15 is controlled. A small amount of exhaust gas may pass through the second exhaust gas flow path 13, but this will not significantly affect the temperature of the exhaust gas exiting the exhaust manifold assembly. The valve means 15 does not inhibit the flow through the second exhaust gas flow path 13, but when the valve means 15 is fully opened, the resistance to the flow of exhaust gas in the second exhaust gas flow path 13 is the first exhaust gas It will be understood that it is higher than the flow path 12. This process continues until the signal from the temperature sensor 20 indicates that the temperature inside the three-way catalyst 16 has reached the light-off temperature of the three-way catalyst 16. This temperature is used as a first predetermined temperature at which the exhaust gas is led primarily to the first exhaust gas flow path 12 when below that temperature. Using the process shown below, this temperature can be derived by a combination of direct measurement using temperature sensor 20 and modeling. For example, if a light-off temperature of 275 ° C. is required for the three-way catalyst 16, the electronic controller 5 uses a look-up table that shows the relationship between the measured temperature and the actual brick temperature. The valve means may be operated to control the exhaust gas flow to the first exhaust gas flow path 12 until the detected temperature reaches 325 ° C. Alternatively, when it is known that there is a temperature deviation of 50 ° C. between the measurement position and the brick center temperature, the predetermined temperature set in the electronic control device 5 is set to 325 ° C.

  At the same time that the three-way catalyst 16 is lighted off, the need for rapid heating is reduced, and the electronic controller 5 determines the temperature of the exhaust gas exiting the exhaust manifold assembly, in its broader sense, at its lower end. When the temperature is below the upper limit, the three-way catalyst 16 and one of the lean NOx traps are bounded by a low temperature limit that does not operate efficiently. A second operating phase is entered, which is intended to be maintained within a predetermined range bounded by the hot temperature limit.

  In the implementation of this embodiment, the electronic control unit 5 operates during this operating phase to maintain the temperature of the exhaust gas in the NOx trap within a temperature range in which the NOx trap operates at maximum efficiency. . If the exhaust gas temperature approaches the upper end of this range, the electronic control unit 5 closes the valve means 15 completely or partially so that more exhaust gas passes through the second exhaust gas flow path 13. The valve means is operated to create a state of flowing through, and if the exhaust gas temperature approaches the lower end of this range, the electronic control unit 5 opens the first exhaust gas passage 12 by opening the valve means 15. Increase the ratio of exhaust gas flow through In this way, the electronic control unit 5 can keep the temperature of the exhaust gas entering the NOx trap 17 within the required temperature range at least while the engine 10 is operating in the lean burn / operation mode.

  If the temperature of the exhaust gas entering the lean NOx trap 17 exceeds the upper limit of the preferred temperature range, the valve means 15 causes the exhaust gas passing through the second exhaust gas flow path 13 by completely closing the valve means 15. Operates to maximize volume. This reduces the effect of temperature aging of the lean NOx trap 17 so that the temperature of the exhaust gas exiting the exhaust manifold assembly is as close as possible to the upper limit of the preferred temperature range. It can be appreciated that while the engine is operating at high loads and speeds, the temperature of the exhaust gas leaving the engine will rise significantly and the cooling demand will likely temporarily exceed the cooling capacity of the exhaust gas cooler 14. Will. Therefore, during these conditions, the aim is to make the temperature of the gas entering the lean NOx trap 17 as low as possible.

  During such a state, the three-way catalyst 16 may also be adversely affected, so that when the electronic control unit 5 causes the temperature of the exhaust gas in the three-way catalyst 16 to exceed a predetermined upper limit temperature, the second emission is performed. It is also possible to operate to maximize the flow through the gas flow path and minimize the flow through the first exhaust gas flow path 12. This is because when the exhaust gas temperature in the three-way catalyst 16 is considerably higher than the temperature in the lean NOx trap 17, there is a considerable temperature difference between the three-way catalyst 16 and the lean NOx trap 17. Especially suitable.

  However, the electronic controller 5 is also programmed to allow the temperature of the exhaust gas entering the lean NOx trap 17 to exceed the upper limit of the preferred temperature range when sulfur needs to be removed from the lean NOx trap 17. . This is because in order to remove sulfur from the lean NOx trap 17, the lean NOx trap 17 must be heated to a high temperature well above the normal operating range, such as 650 ° C.

  When such a desulfurization operation is required, the electronic control unit 5 allows the temperature of the exhaust gas entering the lean NOx trap 17 to allow a significant percentage of the exhaust gas to pass through the first exhaust gas flow path 12. And the valve means 15 is controlled to allow it to rise to the required temperature, which normally requires restricting the flow through the second exhaust gas flow path 13. If the temperature of the exhaust gas leaving the engine is about 675 ° C., no cooling is necessary and the flow mainly passes through the first exhaust gas flow path 12, but if the temperature of the exhaust gas is 800 ° C., this undesirable temperature In order to protect the three-way catalyst 16 and in particular the lean NOx trap 17, a certain amount of cooling action is required. In this case, the valve means 15 allows the flow through both the first exhaust gas passage 12 and the second exhaust gas passage 13 to occur in order to produce the desired desulfurization temperature.

  Therefore, the exhaust gas control device according to the present invention improves the warm-up operation of the engine by recovering heat from the exhaust gas resulting in increased fuel economy and emission reduction at start-up, to the catalytic device. Reduces the risk of premature aging of the catalytic device by the ability to reduce the maximum temperature of the exhaust gas entering, with the three-way catalyst and lean NOx trap in a single unit connected near the engine exhaust manifold Including but not limited to obtaining the opportunity to integrate and improving the capacity of the lean NOx trap by the ability to maintain the temperature of the exhaust gas within a preferred range where optimum efficiency is obtained therein, Has several advantages.

  Since the present invention is particularly advantageous in lean burn engines, the present invention has been described with specific reference to a lean burn engine exhaust gas control system, but is applicable to other types of engines. You can understand. In this case, the lean NOx trap will be replaced by another catalyst or particulate collection device, depending on the type of engine.

  With particular reference to FIGS. 2 and 3, a first embodiment of an exhaust manifold assembly 30 suitable for use in forming part of the aforementioned exhaust control system is shown in more detail.

  The exhaust manifold assembly 30 has four inner exhaust conduits (inner exhaust gas conduits) in the form of exhaust pipes 33 surrounded by a first housing in the form of an inner clamshell 32, and the inner clamshell 32. Are spaced from the exhaust pipe 33 to define a closed volume (closed space). The inner clamshell 32 is itself surrounded by a second housing in the form of an outer clamshell 31 spaced from the inner clamshell 32 to define a closed volume. In this case, the inner and outer clam shells 32 and 31 are each pressed metal parts having two or more components welded together to define individual closed volumes. However, it will be understood that alternative configurations can be used.

  The exhaust pipe 33 as the inner exhaust gas conduit defines a first exhaust gas flow path 12 through the exhaust manifold assembly 30 that is designed to minimize cooling of the exhaust gas. This can be accomplished by minimizing the thermal mass of the exhaust pipe as the inner and outer clamshells 32 and 31 provide the necessary structural rigidity. A volume (space) formed between the exhaust pipe 33 and the inner clam shell 32 forms the second exhaust gas flow path 13, and is formed between the inner clam shell 32 and the outer clam shell 31. The exhaust volume forms the exhaust gas cooler 14.

  The refrigerant from the main cooling circuit of the engine to which the exhaust manifold assembly is coupled in use removes heat from the inner clamshell 32 and moves it, so that the inner clamshell 32 and the outer It circulates through the volume formed between the clam shell 31. That is, heat is removed from the exhaust gas flowing through the second exhaust gas flow path 13 by heat conduction through the inner clamshell 32.

  A single exhaust pipe flange 39 is used in this case to connect the exhaust manifold assembly 30 to an engine (not shown). However, if each exhaust pipe is cooled independently, several exhaust pipe flanges may be used.

  The inner clam shell 32 and the outer clam shell 31 are welded to the exhaust pipe flange 39 in order to fix them to the exhaust pipe flange 39. The exhaust pipe flange 39 has a number of tubular sleeves 34 extending outwardly therefrom for cooperation with the exhaust pipe 33.

  Each of the exhaust pipes 33 is fitted into each of the tubular sleeves 34 to form a slip joint between them. Alternatively, it will be understood that the exhaust pipe can be fitted against the outside of the tubular sleeve.

  The slip joint not only allows movement to occur during heating and cooling of the exhaust pipe 33, but also provides a place for adjustment of the exhaust pipe flange 39 and the exhaust pipe 33. Each of the tubular sleeves 34 is put in place to be adjusted using an opening 39a (only one is visible in FIG. 2) formed in the exhaust pipe flange 39. The opening 39a forms an inlet from the engine to the exhaust manifold assembly 30 and is aligned with the engine exhaust port (not shown).

  Each tubular sleeve 34 has a number of openings 35. These openings are not blocked by the exhaust pipe 33 because the required overlap between the exhaust pipe 33 and the tubular sleeve 34 is only a few millimeters. An opening 35 in the tubular sleeve 34 forms an inlet to a second exhaust gas flow path defined between the exhaust pipe 33 and the inner clamshell 32.

  Alternatively, the opening 35 formed in the tubular sleeve 34 cooperates with an auxiliary opening (not shown) at the end of the exhaust pipe 33. An opening 35 in the tubular sleeve 34 and an auxiliary opening in the exhaust pipe form an inlet to a second exhaust gas flow path defined between the exhaust pipe 33 and the inner clamshell 32.

  Exhaust pipes 33 extend independently from the engine toward a junction 36 where the individual exhaust pipes 33 join to form a single conduit extending from the exhaust manifold assembly 30 toward the exhaust.

  An outlet opening 37 is formed at the outlet end of the second exhaust gas passage 13 to allow the exhaust gas to exit the closed volume and flow to the outlet of the exhaust manifold assembly 30.

  The valve means in the form of a valve assembly 40 is such that the first exhaust gas passage 12 and the second exhaust gas passage slightly upstream from the exhaust port of the exhaust manifold assembly 30 form a single mixed exhaust flow. Therefore, it arrange | positions in the position just before the position combined. The valve assembly 40 is shown in this case to control the flow through only the second exhaust gas flow path 13, but the valve assembly (as shown in FIG. 1) bypasses the first exhaust gas flow path 12. It is equally possible to be placed to control the flow through or to be placed at a location where the first and second exhaust gas passages join to control the flow through both flow paths. It will be possible.

  The valve assembly 40 includes a butterfly valve 41 that is movable by a vacuum actuator 42 via a linkage 43. In use, the vacuum actuator 42 is electrically controlled by an electronic control unit as shown in FIG. It will be appreciated that instead of using a vacuum actuator, an electrical actuator or other suitable actuator may be used.

  The valve assembly 40 is mounted in an outlet housing 38 of the exhaust manifold assembly 30 which in this case is also used as one end of a proximity catalyst canister, such as a three-way catalytic converter (not shown). The As already mentioned, the lean NOx trap can also be mounted in the same canister used for the three-way catalyst. The outlet housing has an internal conduit (not shown) that guides the refrigerant from the inlet 25 to a region surrounding a bearing (not shown) of the butterfly valve 41. This allows the use of inexpensive bearing materials and, in addition, the butterfly valve 41 only regulates the flow rate of gas through the second exhaust gas flow path, so at the outlet of the first exhaust gas flow path 12. It is exposed to a lower temperature than when placed.

  The operation of the exhaust manifold assembly 30 is as follows. The butterfly valve 41 is controlled by an electronic controller to select a position according to the target temperature of the exhaust gas downstream of the exhaust manifold assembly 30.

  When the butterfly valve 41 is moved to the position shown in FIG. 3, the flow through the second exhaust gas passage is not restricted, and therefore the exhaust gas flows through the exhaust pipe 33, that is, directly through the exhaust manifold assembly 30. There is a flow through the first exhaust gas flow path, which passes through the first exhaust gas flow path with relatively low temperature loss, and a flow through the second exhaust gas flow path in which the exhaust gas is cooled. The two exhaust gas streams then mix before exiting the exhaust manifold assembly 30. The resulting gas stream temperature is significantly lower than the temperature of the exhaust gas entering the exhaust manifold assembly 30, depending on the individual temperature and the volumetric flow rate of the two streams. The exhaust manifold assembly 30 can be used to change the temperature of the exhaust gas exiting the exhaust manifold assembly 30 by changing the ratio of these two flows using the valve assembly 40. This is useful for adjusting the temperature of the exhaust gas entering the downstream three-way catalyst or lean NOx trap to operate these catalytic devices at or near maximum efficiency.

  If the butterfly valve 41 moves at right angles to what is shown, the flow through the second exhaust gas flow path is blocked, so that the exhaust gas flow is not exhausted by the exhaust pipe 33 without significant temperature loss. Only through the exhaust manifold assembly 30 directly through the exhaust manifold assembly 30. This is useful when there is a need to supply as high a temperature as possible to the downstream equipment, for example for light-off of a three-way catalyst or lean NOx trap.

  One of the disadvantages of placing the butterfly valve 41 at this position at the end of the second exhaust gas flow path is that the exhaust gas always flows through the first exhaust gas flow path and flows through the second exhaust gas flow path. Only increasing it can limit this flow. This limits the maximum temperature drop that can be achieved, since there are exhaust gas streams that are not always cooled. However, as explained above, the butterfly valve is exposed to lower temperatures by being so arranged, and therefore has the potential to use less expensive materials in its manufacture.

  Referring to FIG. 4, a second embodiment of an exhaust manifold assembly according to the present invention is shown, which in many respects is the same as already described.

  The exhaust manifold assembly 30 has four inner exhaust conduits (inner exhaust gas conduits) in the form of exhaust pipes 133 surrounded by a first housing in the form of an inner clam shell 132. Are spaced from the exhaust pipe 133 to define a closed volume. The inner clamshell 132 is itself surrounded by a second housing in the form of an outer clamshell 131 spaced from the inner clamshell 132 to define a closed volume. As described above, the inner clam shell 132 and the outer clam shell 131 are each pressed metal parts that are welded together to define individual closed volumes.

  The exhaust pipe 133 defines a first exhaust gas flow path through the exhaust manifold assembly 30. The volume formed between the exhaust pipe 133 and the inner clam shell 132 forms the second exhaust gas flow path 13, and the volume formed between the inner clam shell 132 and the outer clam shell 131 is An exhaust gas cooler 14 is formed.

  In use, refrigerant from the main cooling circuit of the engine (not shown) to which the exhaust manifold assembly is connected moves away from the inner clamshell 132 and moves from the inlet 125 to the outlet 126 to move the inner clamshell. It circulates through the volume formed between 132 and the outer clamshell 131.

  In this case, a single exhaust pipe flange 139 is used to connect the exhaust manifold assembly to the engine.

  The inner clam shell 132 and the outer clam shell 131 are welded to the exhaust pipe flange 39 to secure them to the exhaust pipe flange 139. The exhaust pipe flange has a number of tubular sleeves (not visible) extending outwardly therefrom for cooperation with a portion of the exhaust pipe 133.

  Each of the exhaust pipes 133 is fitted on the outside of the tubular sleeve to form a slip joint that allows movement between heating and cooling of the exhaust pipe 133.

  Each of the tubular sleeves is put in place to be adjusted using an opening (not shown) formed in the exhaust pipe flange 139. The opening forms an inlet from the engine to the exhaust manifold assembly and is aligned with the engine exhaust port (not shown).

  Each of the tubular sleeves has a number of openings formed therein to cooperate with the auxiliary opening 135 at the end of the exhaust pipe 133. An opening in the tubular sleeve and an auxiliary opening 135 in the exhaust pipe form an inlet to a second exhaust gas flow path defined between the exhaust pipe 133 and the inner clamshell 132.

  Exhaust pipes 133 extend a small distance independently from the engine to a manifold where individual exhaust pipes 133 combine to form a single conduit extending from the exhaust manifold assembly toward the exhaust. .

  An outlet opening 137 is formed at the outlet end of the second exhaust gas flow path 13 to allow the exhaust gas to exit the closed volume and flow to the outlet of the exhaust manifold assembly.

  Immediately before valve assembly 140 is slightly upstream from the exhaust manifold assembly outlet, where the first exhaust gas flow path and the second exhaust gas flow path are combined to form a single mixed exhaust flow. It is arranged at the position. The valve assembly 140 controls the flow through only the first exhaust gas flow path.

  The valve assembly 140 includes a butterfly valve 141 that is movable by a vacuum actuator 142 via a linkage 143. In use, the vacuum actuator 142 is electrically controlled by an electronic control unit as shown in FIG.

  The valve assembly 140 is mounted in an outlet housing 138 of the exhaust manifold assembly 30 which in this case is also used as one end of a proximity catalyst canister, such as a three-way catalytic converter (not shown). The As already mentioned, the lean NOx trap can also be mounted in the same canister used for the three-way catalyst. The outlet housing 138 has an internal conduit (not shown) that guides the refrigerant from the inlet 125 to a region surrounding the butterfly valve 141 bearing (not shown).

  The operation of the exhaust manifold assembly is as follows. The butterfly valve 141 is controlled by an electronic controller to select a position according to the target temperature of the exhaust gas downstream of the exhaust manifold assembly.

  When the butterfly valve 141 is moved to the position shown in FIG. 4, the flow through the first exhaust gas flow path is not restricted, and therefore the exhaust gas flow passes through the exhaust pipe 133, i.e., directly through the exhaust manifold assembly. There is a relatively low temperature loss flow through and a flow through the second exhaust gas flow path in which the exhaust gas is cooled. The two exhaust gas streams then mix before exiting the exhaust manifold assembly 30. The temperature of the resulting gas stream depends on the individual temperature and the volume flow rate of the two streams, and because of the difference in flow resistance, the majority of the stream passes through the first exhaust gas flow path. By changing the ratio of these two flows, the exhaust manifold assembly 30 can be used to change the temperature of the exhaust gas exiting the exhaust manifold assembly 30. This is useful for adjusting the temperature of the exhaust gas entering the downstream three-way catalyst or lean NOx trap to operate these catalytic devices at or near maximum efficiency.

  When the butterfly valve 141 is moved at right angles to what is shown, the flow through the first exhaust gas flow path is blocked, so that the exhaust gas is a second exhaust gas flow path for maximum cooling effect. It must flow mainly. This arrangement reduces the exhaust gas temperature below the temperature at which premature aging of equipment located downstream of the exhaust manifold assembly occurs, or at least any temperature above such temperature. Useful for minimizing displacement.

  When the butterfly valve 141 is so arranged, the ratio of the exhaust gas flowing through the second exhaust gas passage is such that the catalyst placed downstream when the butterfly valve 141 is in the position shown in FIG. It should be understood that the exhaust gas temperature should be set so that a sufficient exhaust gas temperature can be provided to provide a quick light off. This may change the size and number of openings 135 that change the resistance to flowing through the second exhaust gas flow path, or change the size of the gap between the exhaust pipe 133 and the inner clamshell 132. Or a combination thereof.

  With reference to FIGS. 5 and 6, a third embodiment of an exhaust manifold assembly according to the present invention is shown.

  The exhaust manifold has four inner exhaust conduits (inner exhaust gas conduits) in the form of exhaust pipes 233 defining a first exhaust gas flow path through the exhaust manifold assembly and a valve assembly 240, which is the valve assembly 240. A butterfly valve 241 as a movable valve means disposed at the end of the first exhaust gas flow path, a first cooling conduit 213a that provides a flow path from the butterfly valve 241 to the exhaust gas cooler 214, and a discharge It has a second cooling conduit 213 b that provides a flow path from the outlet of the gas cooler 214 back to the butterfly valve 241.

  Exhaust gas flowing from the engine through the exhaust manifold assembly via the exhaust pipe 233 and then through the first and second cooling conduits 213a, 213b and the exhaust gas cooler follows the second exhaust gas flow path.

  In use, refrigerant from the main cooling circuit of an engine (not shown) to which the exhaust manifold assembly is coupled circulates through the exhaust gas cooler to cool the exhaust gas passing through the exhaust gas cooler 214.

  A single exhaust pipe flange 239 is used to couple the exhaust manifold assembly to the engine, and each of the exhaust pipes 233 is welded directly to the exhaust pipe flange 239.

  Exhaust pipes 233 extend independently from the engine a small distance to the manifold where the individual exhaust pipes 233 combine to form a single conduit that extends toward the valve assembly 240.

  Valve assembly 240 is positioned slightly upstream from the exhaust manifold assembly outlet at a location where the first exhaust gas flow path and the second exhaust gas flow path are joined to form a single mixed exhaust flow. Established. The valve assembly 240 adjusts the flow rates of both exhaust gas passages, or specifically determines how much exhaust gas should be diverted through the exhaust gas cooler 214.

  The valve assembly 240 includes a butterfly valve 241 that is movable by a vacuum actuator 242 via a linkage 243. In use, the vacuum actuator 242 is electrically controlled by an electronic control unit as shown in FIG.

  The valve assembly 240 is mounted in an outlet housing 238 of the exhaust manifold assembly 30, which in this case is also used as one end of a proximity catalyst canister, such as a three-way catalytic converter (not shown). The As already mentioned, the lean NOx trap can also be mounted in the same canister used for the three-way catalyst. In this case, the outlet housing 238 is a casting, and is a casting as a single member provided with two cooling conduits 213a and 213b. However, it will be understood that other forms of configurations and designs may be used.

  The operation of the exhaust manifold assembly is as follows. The butterfly valve 241 is controlled by an electronic controller to select a position according to the target temperature of the exhaust gas downstream of the exhaust manifold assembly.

  When the butterfly valve 241 moves to the position shown in FIGS. 5 and 6, the flow through the first exhaust gas passage and the second exhaust gas passage is not limited. However, most of the exhaust gas flows through the exhaust manifold, i.e., directly through the exhaust manifold assembly with little temperature loss. This is because there is a high flow resistance when the exhaust gas passes through the exhaust gas cooler 214 and because the inertia of the exhaust gas allows the exhaust gas to pass through the inlet of the first cooling conduit 231a.

  Therefore, when the butterfly valve 241 is in this position, the exhaust gas mainly passes through the first exhaust gas passage, so that the temperature between the exhaust gas entering the exhaust manifold assembly and the exhaust gas temperature exiting the exhaust manifold assembly is between There is almost no difference. However, a small flow of exhaust gas flows through the exhaust gas cooler 214 that can be used to help warm the refrigerant in the main engine cooling circuit.

  The two exhaust gas streams are then mixed prior to exiting the exhaust manifold assembly. The resulting gas stream temperature depends on the individual temperature and the volumetric flow rate of the two streams.

  When the butterfly valve is moved to a position of 45 degrees with respect to the position shown in FIG. 5, as indicated by reference numeral 214a in FIG. 6, the flow through the first exhaust gas passage is blocked and all exhaust gases are blocked. However, it has to pass through the second exhaust gas passage. It will be understood that the second exhaust gas flow path includes not only the exhaust pipe 233 as the exhaust gas conduit but also the first cooling conduit 213a, the second cooling conduit 213b, and the exhaust gas cooler 214. This valve position reduces the temperature of the exhaust gas exiting the exhaust manifold assembly as much as possible so that the temperature of the exhaust gas exiting the exhaust manifold assembly is premature for any device mounted downstream of the exhaust manifold. This is useful for preventing the occurrence of aging. Since the cooling capacity of the exhaust gas cooler 214 can be exceeded by operating the engine near maximum power, it does not mean that the exhaust gas does not reach a high temperature, but it is as low as possible. For example, if the exhaust gas cooler is capable of producing a 150 ° C. temperature drop and the exhaust gas temperature rises to 800 ° C., the temperature of the exhaust gas exiting the exhaust manifold assembly is still 650 ° C. Is less affected by aging compared to a temperature of 800 ° C.

  Therefore, by changing the position of the butterfly valves 241, 241a between these two positions, the ratio of cooled exhaust gas to uncooled exhaust gas can be changed. This means that the exhaust manifold assembly can change the outlet temperature of the exhaust gas moving downstream, and the exhaust manifold assembly keeps the catalytic device or lean NOx trap at or near maximum operating efficiency. It can be used to

  Referring to FIG. 7, an alternative valve arrangement is shown that is intended to directly replace the valve arrangement shown in FIG.

  In this case, a penny valve 341 as a valve means is used instead of the butterfly valve.

  The main difference between this valve arrangement and the previously described valve arrangement is that when the penny valve 341 is in the first position indicated by reference numeral 341 in FIG. 7, the outlet of the second cooling conduit 213b is covered. There is no flow through the second exhaust gas flow path. When the valve member is in the second position indicated by reference numeral 341a in FIG. 7, all of the exhaust gas flows through the second exhaust gas flow path and does not flow through the first exhaust gas flow path. Can not. This arrangement thus makes it possible to selectively stop both exhaust gas passages. This makes it possible to further increase the temperature of the exhaust gas supplied during engine warm-up compared to the arrangement shown in FIG.

  As already mentioned, the penny valve 341 is movable to allow the temperature of the exhaust gas exiting the exhaust manifold assembly to be adjusted to meet the various operating requirements described above.

  One advantage of the valve arrangement shown in FIG. 7 is that the bearings of the penny valves 341, 341a are placed at the outlet of the second cooling conduit 213b, so that they are sometimes exposed to the cold exhaust gas coming out of the second cooling conduit 213b. As a result, inexpensive bearing materials can be used. Also, a small amount of leakage is allowed so that the cooled exhaust gas flow can cool the rear surface of the penny valve 341 even when the majority of the exhaust gas flows out of the exhaust manifold assembly without being cooled. It may be possible to exceed the penny valve 341.

  Although the invention has been described by way of example with reference to one or more embodiments, the invention is not limited to the described embodiments and is a modified or alternative embodiment to the described embodiments. It will be appreciated by those skilled in the art that can be constructed without departing from the scope of the present invention.

It is a block diagram of the exhaust-gas control apparatus by this invention. 1 is a perspective sectional view of a first embodiment of an exhaust gas control apparatus according to the present invention. FIG. 3 is an enlarged view of the valve assembly portion of FIG. 2. It is a perspective sectional view of a 2nd embodiment of an exhaust gas control device by the present invention. It is a perspective sectional view of a 3rd embodiment of an exhaust gas control device by the present invention. FIG. 6 is a cross-sectional view of the valve assembly of FIG. 5. FIG. 7 illustrates an alternative embodiment of the valve assembly of FIG.

Explanation of symbols

5 Electronic control device 10 Engine (internal combustion engine)
12 First exhaust gas passage 13 Second exhaust gas passage 14 Exhaust gas cooler 15 Valve means 16 Three-way catalyst 17 NOx trap 20 Temperature sensor (exhaust temperature sensor)
25 Inlet 26 Outlet 30 Exhaust manifold assembly 31 Outer clam shell (second housing)
32 Inner clam shell (first housing)
33 Exhaust pipe (exhaust gas conduit)
34 Tubular sleeve 35 Opening 36 Joint 40 Valve assembly 41 Butterfly valve (valve means)
125 inlet 126 outlet 131 outer clamshell (second housing)
132 Inner clamshell (first housing)
133 Exhaust pipe (inner exhaust gas conduit)
140 Valve assembly 141 Butterfly valve (valve means)
213a First cooling conduit 213b Second cooling conduit 214 Exhaust gas cooler 233 Exhaust pipe (inner exhaust gas conduit)
240 Valve assembly 341 Penny valve (valve means)

Claims (45)

An inlet through which exhaust gas from the engine flows into in use,
An exhaust port through which exhaust gas flows out during use,
A first exhaust gas flow path for moving the exhaust gas from the inlet to the outlet;
A second exhaust gas flow path for moving the exhaust gas from the inlet to the outlet;
An exhaust manifold assembly for an internal combustion engine, comprising: valve means for adjusting a flow rate of the steam exhaust gas flowing through the first exhaust gas passage and the second exhaust gas passage;
The exhaust gas flowing through the first exhaust gas flow path through the exhaust manifold assembly undergoes minimal cooling;
The exhaust manifold assembly wherein the exhaust gas flowing through the second exhaust gas flow path is actively cooled by an exhaust gas cooler so that the temperature of the exhaust gas exiting the exhaust manifold assembly can be adjusted. Solid. The valve means operates so that all or most of the exhaust gas from the internal combustion engine passes through the first exhaust gas passage when the internal combustion engine is started at a low temperature. An exhaust manifold assembly as described. The valve means operates such that all or most of the exhaust gas from the internal combustion engine passes through the first exhaust gas flow path when at least the exhaust gas temperature falls below a first predetermined temperature. The exhaust manifold assembly according to claim 1 or 2. 2. The valve means according to claim 1, wherein when the upper air exhaust gas temperature exceeds a second predetermined temperature, at least a part of the exhaust gas passes through the second exhaust gas flow path. The exhaust manifold assembly according to any one of claims 1 to 3. The valve means is operative to change the ratio of exhaust gas flowing through the first exhaust gas passage and the second exhaust gas passage to regulate the temperature of the exhaust gas exiting the exhaust manifold assembly. An exhaust manifold assembly according to any one of claims 1 to 4, characterized in that 6. The exhaust gas of claim 1, wherein the exhaust gas is adjusted to maintain a temperature of the exhaust gas exiting the exhaust manifold assembly within a predetermined temperature range. Exhaust manifold assembly. 7. A valve as claimed in claim 1, wherein the valve means is a single control valve placed in place to regulate the flow rate of exhaust gas through the first exhaust gas flow path. An exhaust manifold assembly according to claim 1. 8. An exhaust manifold assembly as claimed in claim 7, wherein the valve means is positioned in the vicinity of the exhaust port to selectively limit the flow rate of exhaust gas exiting the first exhaust gas flow path. 7. A valve according to claim 1, wherein the valve means is a single control valve placed in place to regulate the flow rate of exhaust gas through the second exhaust gas flow path. An exhaust manifold assembly according to claim 1. 10. An exhaust manifold assembly as claimed in claim 9, wherein the valve means is positioned in the vicinity of the exhaust port to selectively limit the flow rate of exhaust gas exiting the second exhaust gas flow path. The valve means is a single control valve placed in place to simultaneously adjust the flow rate of exhaust gas passing through the first exhaust gas passage and the second exhaust gas passage. An exhaust manifold assembly according to any one of the preceding claims. The valve means is disposed in the vicinity of the exhaust port so as to selectively change the flow rate of exhaust gas exiting from the first exhaust gas passage and the second exhaust passage. The exhaust manifold assembly according to claim 11. The exhaust manifold assembly according to any one of claims 1 to 12, wherein the exhaust gas cooler uses a refrigerant taken from a main cooling device of the internal combustion engine. The exhaust manifold assembly is
At least one inner exhaust gas conduit defining the first exhaust gas flow path;
A first housing surrounding the inner exhaust gas conduit and spaced apart from the inner exhaust gas conduit to define the second exhaust gas flow path;
A second casing surrounding the first casing and spaced apart from the first casing to define a gap through which a refrigerant for forming the exhaust gas cooler passes. 14. An exhaust manifold assembly according to any one of the preceding claims. 15. An exhaust manifold assembly according to claim 14, wherein each of the inner exhaust gas conduits is connected to the exhaust port of the internal combustion engine by a flange plate. The exhaust manifold assembly of claim 15, wherein the flange plate has a tubular sleeve extending therefrom to engage an end of the inner exhaust gas conduit. The exhaust manifold assembly includes a single flange plate,
The exhaust manifold assembly according to claim 14, wherein the exhaust manifold assembly has the same number of tubular sleeves as the cylinders of the internal combustion engine to which the exhaust manifold assembly is coupled. 18. Each of the tubular sleeves has one or more openings therein for providing an inlet to the second exhaust gas flow path. Exhaust manifold assembly. Each of the tubular sleeves cooperates with one or more corresponding openings in the end of the inner exhaust gas conduit with which it engages to provide an inlet to the second exhaust gas flow path. 18. An exhaust manifold assembly according to claim 16 or 17 having one or more openings therein. The exhaust manifold assembly according to any one of claims 14 to 19, wherein the manifold assembly comprises a plurality of inner exhaust gas conduits forming the first exhaust gas flow path. 21. The inner exhaust conduit for flowing exhaust gas from an internal combustion engine to a junction where the separated inner exhaust conduit merges to form a single conduit extending to an outlet. An exhaust manifold assembly according to claim 1. The first exhaust gas flow path is formed by one exhaust gas conduit;
The control means is a control valve located at the outlet end of the exhaust gas conduit;
The second exhaust gas flow path connects a first cooling conduit connecting the exhaust gas conduit and the control valve to an inlet of the exhaust gas cooler, and a second connecting the control valve from an exhaust port of the exhaust gas cooler. Formed by two cooling conduits,
14. The control valve according to claim 1, wherein the control valve operates to adjust a flow rate of exhaust gas passing through the first exhaust gas passage and the second exhaust gas passage. Exhaust manifold assembly. Comprising several exhaust gas conduits for independently flowing exhaust gas from the internal combustion engine to a connection point where each conduit merges to form a single conduit extending to the control valve therein. 23. An exhaust manifold assembly according to claim 22. From the first position where all exhaust gas flows from the inlet to the outlet through only the first exhaust gas passage, the control valve passes from the inlet through the second exhaust gas passage. The exhaust manifold assembly according to claim 22 or 23, wherein the exhaust manifold assembly is movable to a second position where all exhaust gas flows to the exhaust port. When the control valve is positioned between the first position and the second position, a part of the exhaust gas flows through the first exhaust gas flow path, and the remainder of the exhaust gas is the second exhaust gas. 25. The exhaust manifold assembly of claim 24, wherein the exhaust manifold assembly flows through a flow path. 26. The position of the control valve between the first position and the second position is changed to adjust the temperature of the exhaust gas exiting through the exhaust port. An exhaust manifold assembly according to claim 1. 27. An exhaust manifold set according to any one of claims 24 to 26, wherein when the control valve is in the first position, exhaust gas flow through the second cooling conduit is substantially impeded. Solid. 28. A slight leakage of exhaust gas through the control valve is allowed to cool the control valve even when the control valve is in the first position. Exhaust manifold assembly. An exhaust gas control apparatus for an internal combustion engine, comprising: the exhaust manifold assembly according to any one of claims 1 to 28; and a catalyst device connected to an exhaust port from the exhaust manifold assembly. 30. The exhaust gas control device according to claim 29, wherein the catalyst device is a three-way catalyst. 31. The exhaust gas control device of claim 30, wherein the exhaust gas control device further comprises a lean NOx trap placed downstream of the three-way catalyst. 32. The exhaust gas control of claim 31, wherein the three way catalyst and the lean NOx trap are mounted in a common canister directly connected to the exhaust port of the exhaust manifold assembly. apparatus. The exhaust gas control device further comprises an electronic control device and an exhaust temperature sensor operably coupled to the electronic control device to provide a signal representative of the exhaust gas temperature downstream of the exhaust manifold. An exhaust gas control device according to any one of claims 29 to 32. The exhaust gas control device according to claim 33, wherein the valve means is a control valve, and the position of the control valve is controlled by the electronic control device. 35. The exhaust gas control device according to claim 34, wherein the position of the control valve is controlled by the electronic control device according to one of signals received from the exhaust temperature sensor and an exhaust temperature model. The electronic control unit operates the control valve so that when the detected exhaust gas temperature is lower than a first predetermined temperature, the exhaust gas is simply or mainly moved to a position where the exhaust gas flows through the first exhaust gas passage. 36. The exhaust gas control device according to claim 35, wherein 37. The exhaust gas control device according to claim 36, wherein the first predetermined temperature is a light-off temperature of the three-way catalyst coupled to the exhaust manifold. The three-way catalyst is connected to an exhaust port from the exhaust manifold;
The lean NOx trap is placed downstream of the three way catalyst;
36. The exhaust of claim 35, wherein the electronic controller is operative to control the position of the control valve to maintain the temperature of the exhaust gas in the lean NOx trap within a predetermined temperature range. Gas control device. The lower end of the boundary is determined by a lower temperature limit at which the lean NOx trap does not operate efficiently when the predetermined temperature range falls below that temperature, and when the temperature exceeds the predetermined temperature range, the lean NOx trap is prematurely aged. The exhaust gas control device according to claim 38, wherein an upper end of the boundary is determined by a temperature limit. 39. The exhaust gas control device according to claim 38, wherein the predetermined temperature range is a temperature range in which the lean NOx trap operates with maximum efficiency. 40. The electronic controller of claim 39, wherein the electronic controller is operative to allow the exhaust gas temperature to exceed the upper temperature limit when sulfur needs to be removed from the lean NOx trap. Exhaust gas control device. An exhaust manifold assembly according to any one of claims 1 to 28;
A three way catalyst coupled to the outlet of the exhaust manifold assembly;
In a control method of an exhaust gas control device comprising a lean NOx trap placed downstream of the three-way catalyst,
After starting the internal combustion engine, all or most of the exhaust gas is removed until the exhaust gas temperature corresponding to the light-off temperature of the three-way catalyst is reached in order to quickly light off the three-way catalyst. Providing a flow path through the first exhaust gas flow path. Changing the flow rate of exhaust gas through the first exhaust gas flow path and the second exhaust gas flow path so that the exhaust gas temperature in the lean NOx trap stays in a range where the lean NOx trap operates at maximum efficiency. 43. The method of claim 42, further comprising: controlling a temperature of exhaust gas passing through the three-way catalyst and the lean NOx trap. When the exhaust gas temperature exceeds the upper temperature limit where premature aging of one of the three-way catalyst and lean NOx trap is approached, all or most of the exhaust gas passes through the second exhaust gas flow path. 44. The method of claim 42 or 43, further comprising providing a flow path therethrough. 45. The method of claim 44, further comprising allowing the exhaust gas temperature to deviate above the upper temperature limit when sulfur needs to be removed from the lean NOx trap. Method.

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