DE102004010117A1 - Exhaust gas recirculation circuit for motor vehicle internal combustion engine has regulating valve connected to heat exchanger outlet and bypass pipe - Google Patents

Abstract

The exhaust gas return system for a motor vehicle internal combustion engine has the exhaust gas flow rate ratio regulating valve (18) at the downstream side of the exhaust gas heat exchanger (14) and the bypass pipe (14). The regulating valve has a first inlet opening (41) for exhaust gas from the heat exchanger and a second inlet opening (42) for gas from the bypass pipe, controlled by valve members (61,62). The heat exchanger inlet is opened when the engine is stopped.

Description

The The present invention relates to an exhaust gas recirculation device, which a Exhaust gas recirculation passage to return one Contains amount of an exhaust gas from an exhaust duct to an intake duct. The Exhaust gas recirculation device contains a heat exchanger for cooling of the exhaust gas and a bypass pipe which is connected to the heat exchanger in the exhaust gas recirculation duct leads past. The heat exchanger is used as an EGR gas cooler designated.

In a conventional one Exhaust gas recirculation device is in the exhaust gas recirculation pipe Exhaust gas recirculation flow rate control valve provided which is a flow rate the back to the suction side to lead Exhaust gas sets because the recirculation of the Exhaust gas to the intake side a deterioration in engine performance can cause. The exhaust gas recirculation device contains an EGR gas cooler in the EGR pipe to return the Exhaust gas in the internal combustion engine. This is because when the exhaust gas, which is returned to the intake duct of the internal combustion engine, cooled in the middle of the EGR tube is reduced, a temperature of the exhaust gas and a volume is reduced and it becomes possible is the generation of nitrogen oxide (NOx) by lowering a combustion temperature to effectively reduce the fuel inside the internal combustion engine. However, if the EGR gas cooler is provided in the middle of the EGR pipe, the exhaust gas that is in the internal combustion engine is returned, inevitably chilled, and with that, even if the exhaust gas is in a cold season is returned an idle effect on intake air small. That though in general the repatriation of the Exhaust gas of a high temperature to the intake side in the cold Season can achieve the idle effect on the intake air it impossible since the exhaust gas, which is cooled by the EGR gas cooler, during the cold season is returned to the suction side, to achieve the sufficient idle effect, which creates a case that the sensitivity to ignition of the internal combustion engine is lowered and during the cold season a white one Smoke is generated.

Here, for the purpose of optimizing the temperature of the exhaust gas in accordance with the operating state of the internal combustion engine, an exhaust gas recirculation device (EGR gas device) has been proposed, in which a cooling duct with a heat exchanger (EGR cooler) for cooling an EGR gas by means of engine cooling water and a bypass duct, which the Bypasses the cooling passage, in the middle of the exhaust gas recirculation duct (EGR duct) for returning a part of the exhaust gas from the internal combustion engine (exhaust gas recirculation gas: EGR gas) and an exhaust gas flow rate ratio control valve (three-way valve) for regulating an EGR gas flow rate ratio between the cooling duct and the bypass duct in the cooling passage is provided on the downstream side of the EGR gas cooler, and an exhaust gas recirculation flow rate control valve (flow rate ratio control valve) for regulating a total EGR amount is provided near an outlet of the EGR passage (for example, Japanese unexamined patent publisher Release 11-280565, page 1 to page 6, 1 ). This EGR device is by connecting an exhaust gas recirculation flow pipe and a branch section to a flow bundle section using a bypass pipe, connecting the branch section to an EGR gas cooler using an exhaust gas recirculation flow pipe, connecting the EGR gas cooler to the mixing section using an intake pipe exhaust gas recirculation flow , and constructed by connecting the flow bundle portion to an intake pipe using an intake-side exhaust gas recirculation flow pipe. Furthermore, the engine cooling water is sent so that the engine cooling water circulates between an engine and the EGR gas cooler through a pair of cooling water pipes.

Regarding the in the above Japanese Unexamined Patent Publication 11-280565 However, the three-way valve, the EGR gas cooler, the bypass pipe and the Flow rate control valve each set up as individual units. Accordingly, the exhaust gas recirculation pipes, which feed an EGR gas into the respective individual units, used to connect the units, and a channel length of the EGR channel becomes extremely long overall. In particular, there is a delay in reaction, if a flow rate ratio of the EGR gas between the cooling channel and the bypass channel is set, and therefore it is difficult the sophisticated one Perform temperature control. Outside air also acts on the exhaust gas recirculation pipes, with which the respective individual units are connected, and therefore, the EGR gas temperature tends to be controlled by regulating the flow rate ratio of the EGR gas between the cooling channel and the bypass channel is achieved to change slightly, thereby it is difficult the sophisticated Perform temperature control. Accordingly it is impossible that EGR gas, which corresponds to the operating state of the internal combustion engine is regulated to the optimal temperature to mix into the intake air, which creates disadvantages in performance features, in particular deterioration of a NOx reduction effect in the exhaust gas.

It is also related to the temperature of the EGR gas to achieve the satisfactory NOx reduction effect in the exhaust gas and also to protect inner components of the three-way valve and inner components of the flow rate control valve from heat, the engine cooling water other than in the EGR gas cooler into the three-way valve and the flow rate- Initiate control valve. In this case, cooling water pipes are required to circulate the engine cooling water in the EGR gas cooler, the three-way valve, and the flow rate ratio control valve between the engine and these elements. Furthermore, a cooling water pipe is necessary, which connects a cooling water channel of the EGR gas cooler and a cooling water channel of the three-way valve. In addition, a cooling water pipe is required which connects a cooling water channel of the EGR gas cooler and a cooling water channel of the flow rate control valve. Accordingly, the number of components of the EGR gas cooling device that are necessary for the EGR device is increased as a whole, and the arrangement also becomes bulky, causing a disadvantage that the assemblability of the EGR device inside an engine compartment of a vehicle is deteriorated.

Furthermore, an exhaust gas recirculation device (EGR device) has also been proposed, in which a cooling duct with a heat exchanger (EGR gas cooler), which cools an EGR gas by means of engine cooling water, and a bypass duct, which bypasses the cooling duct, in the middle of an EGR -Channel that returns EGR gas from an exhaust passage to an intake passage, an exhaust gas flow rate ratio control valve for regulating an EGR gas flow rate ratio between the cooling passage and the bypass passage on an upstream side of an EGR gas cooler of the cooling passage and an inlet side of the bypass passage is provided, and an EGR control valve that regulates a total EGR amount is provided on a downstream side of a flow mixing portion of an outlet side of the cooling passage and an outlet side of the bypass passage (see European patent publication EP 1 030 050 A1 , Page 1 to page 7, 1 to 3 ).

In the in the European patent publication EP 1 030 050 A1 described EGR device, however, the exhaust gas flow rate ratio control valve is arranged on the upstream side of the EGR gas cooler, which forms the cooling channel in the interior thereof, and the bypass tube, which forms the bypass channel in the interior thereof, so that when the EGR gas temperature is corresponding a change in a target value of the EGR gas temperature changes, the control response sensitivity is deteriorated by an amount corresponding to a volume (length) of the EGR gas cooler and the bypass passage, making it difficult to perform the sophisticated control of the EGR gas temperature. Here, it may be possible to provide the exhaust gas flow rate ratio control valve on the downstream side of the EGR gas cooler, which forms the cooling channel in the inside thereof, and the bypass pipe, which forms the bypass channel in the inside thereof.

however is the exhaust gas flow rate ratio control valve provided in the EGR channel in which an exhaust gas flows, which tiny particles of combustion residues, carbon and the like contains. Especially the tiny particles, which after passing through the EGR gas cooler chilled stick to an EGR gas cooler side Exhaust flow rate ratio control valve element and form an adhesive deposit (whereby the adhesiveness on the low temperature side compared to the high temperature side is higher). Then if the EGR gas cooler side Exhaust flow rate ratio control valve element rests on a valve seat and an inlet opening, which the EGR gas closed into the interior of the EGR duct on the intake duct side by the EGR gas cooler , an adhesive deposit is layered so that the deposit is on the EGR gas cooler side Valve element and the valve seat of the exhaust gas flow rate ratio control valve progresses, whereby the EGR gas cooler-side valve element of the exhaust gas flow rate ratio control valve firmly adheres to the valve seat, causing the opening / closing process of the EGR gas cooler side Valve element of the exhaust gas flow rate ratio control valve by an actuator formed from a membrane or the like not done quietly can be.

It is an object of the present invention, an exhaust gas recirculation device to provide a sophisticated control of an exhaust gas temperature simply inside an exhaust gas recirculation duct carry out can. Furthermore, it is a further object of the present invention an exhaust gas recirculation device to provide a determination of a heat exchanger side valve of an exhaust gas flow rate ratio control valve can prevent due to detention. It is still one Another object of the present invention, an exhaust gas recirculation device to provide the ability to mount it on a vehicle Shorten a channel length an exhaust gas recirculation duct and improve a cooling water circulation channel can. It is another object of the present invention, one Provide exhaust gas recirculation device, which is the production of nitrogen oxide without being accompanied by less Output power of an internal combustion engine and lower operability of the internal combustion engine can effectively reduce.

According to the present Invention is in an exhaust gas recirculation device with an exhaust gas recirculation duct to return a Part of an exhaust gas in an internal combustion engine to an intake side Exhaust gas flow rate ratio control valve, which a relationship between a flow rate of the Exhaust gas that flows inside the exhaust gas heat exchanger, and a flow rate of the exhaust gas, which flows inside the bypass pipe, continuously or regulates gradually, near the downstream side an exhaust gas heat exchanger, which cools the exhaust gas which is inside the exhaust gas recirculation duct and a bypass tube which the inside of the exhaust gas circulation channel from the exhaust gas heat exchanger flowing Exhaust gas bypasses, cools, intended. With such a structure, the exhaust gas flow rate ratio control valve can the low temperature exhaust gas coming from the exhaust gas heat exchanger is introduced to the suction side by means of the first inlet opening, and the high temperature exhaust gas coming from the bypass pipe by means of the second discharge opening to the suction side is mixed.

Further is achieved by providing the exhaust gas flow rate ratio control valve nearby the downstream Side of the exhaust gas heat exchanger and of the bypass pipe, if an exhaust gas temperature changes inside the exhaust gas recirculation duct, the control response sensitivity of the exhaust gas flow rate ratio control valve by a measure accordingly a volume (a length) of the exhaust gas heat exchanger and the bypass tube improved. Accordingly, there is no way that the exhaust gas temperature inside the exhaust gas recirculation duct is above or below a setpoint shoots abnormally, causing it possible is the sophisticated control of the exhaust gas temperature inside of the exhaust gas recirculation duct to perform so that the exhaust gas temperature quickly converges to the setpoint.

Further is the exhaust gas flow rate ratio control valve with a first inlet opening, which introduces the exhaust gas from the exhaust gas heat exchanger, a second inlet opening, which introduces the exhaust gas from the bypass pipe and a valve, which has at least one opening area of the first introducing opening from the first opening and the second introduction opening adjusts nearby the downstream Exhaust gas heat exchanger side and the bypass pipe, and the valve of the exhaust gas flow rate ratio control valve is designed to open when the operation of the internal combustion engine is stopped. Through a there is such a structure even if tiny ones contained in the exhaust gas Particles adhere to the valve on the exhaust gas heat exchanger side and one Detention is formed, no way that the detention on the valve of the exhaust gas flow rate ratio control valve and a valve housing (for example, a valve seat) layered in an overarching manner becomes so that it becomes possible is determining the valve of the exhaust gas flow rate ratio control valve to prevent. Accordingly, the opening / closing operation of the Exhaust gas flow rate ratio control valve for example, can be carried out quietly by an actuator and therefore the Control response sensitivity of the exhaust gas flow rate ratio control valve be improved.

Further can the exhaust gas recirculation flow pipe (Pipeline), which includes the exhaust gas heat exchanger and the exhaust gas flow rate ratio control valve connects, and the exhaust gas recirculation flow pipe (Pipeline) which the bypass pipe and the exhaust gas flow rate ratio control valve connects, extremely shortened and therefore the construction of the pipeline can be simplified. The assembly is accordingly Simplified and the channel length of the exhaust gas recirculation channel can be short can be made and therefore the ability to mount on a vehicle can be improved become. It is also possible because the total flow rate of the exhaust gas flowing through the interior of the exhaust gas recirculation channel to the Intake side of the internal combustion engine can be optimally returned, the generation of the nitrogen oxide without being accompanied by a lower one Output power of the internal combustion engine and lower operability to effectively reduce the internal combustion engine. It is also possible that Exhaust gas to the intake side of the internal combustion engine through optimization the temperature of the exhaust gas, which through the interior of the exhaust gas recirculation channel flows, return and therefore the sensitivity to ignition in the internal combustion engine with the sufficient idling effect the intake air can be greatly improved.

According to a further aspect of the present invention, the exhaust gas flow rate ratio control valve is constructed such that a first valve element on the exhaust gas heat exchanger side opens the first introduction opening, which introduces the exhaust gas from the exhaust gas heat exchanger, with a predetermined opening degree or more when a second valve element on the bypass pipe side opens second inlet opening, which introduces the exhaust gas from the bypass pipe, opens completely. That is, even if the high-temperature exhaust gas from the bypass pipe is introduced through the second introduction opening, by adjusting the construction that does not completely close the first introduction opening, internal components can be formed due to the low-temperature exhaust gas that is introduced from the exhaust gas heat exchanger through the first introduction opening of the exhaust gas flow rate ratio control valve. Accordingly, it is possible to prevent the internal components of the exhaust gas flow rate ratio control valve from heat of the exhaust gas To protect it, and thus the control response sensitivity of the exhaust gas flow rate ratio control valve can be improved.

Further is a normally open valve as the first valve element the exhaust gas heat exchanger side used, and a normally closed valve is the second Valve element inserted on the bypass tube side, so that even when an actuator of the exhaust gas flow rate ratio control valve is not controllable, the low temperature exhaust gas, which by Stream through the exhaust gas heat exchanger chilled is in the exhaust gas flow rate ratio control valve can penetrate. Even if the actuator of the exhaust gas flow rate ratio control valve malfunction, it is accordingly possible to remove the internal components of the exhaust gas flow rate ratio control valve protect from heat of the exhaust gas high temperature, causing the secondary malfunction the exhaust gas recirculation device can be prevented.

According to one Another aspect of the present invention is the exhaust gas flow rate ratio control valve constructed so that it opens the first valve element on the exhaust gas heat exchanger side and the second valve element on the bypass tube side closes when the operation of the internal combustion engine is stopped. Through one There is structure even if tiny particles contained in the exhaust gas on the first valve element of the exhaust gas flow rate ratio control valve on the exhaust gas heat exchanger side cling and a custody deposit is formed, no way that the adhesive deposit on the first valve element of the exhaust gas flow rate ratio control valve on the exhaust gas heat exchanger side and a valve housing (e.g. a valve seat) in a sweeping Layered way so that it is possible to find out the valve of the exhaust gas flow rate ratio control valve to prevent. Accordingly, the opening / closing operation the valve of the exhaust gas flow rate ratio control valve for example, can be performed quietly by an actuator, and therefore can the control response sensitivity of the exhaust gas flow rate ratio control valve be improved.

According to one Another aspect of the present invention is the valve from a Double plate valve constructed, which has a first flange section with an approximately circular shape, which forms the first valve element, and a second flange portion having an approximately circular shape, which forms the second valve element and a shaft-like section, which integrates the lifting process with the first flange section and performs the second flange section. With such a structure can compared to a corresponding valve that the lifting process of the first flange section and the second flange section by means of performs separate shaft-like sections, the number of parts and the Man hours for assembly can be reduced, thereby reducing costs becomes.

According to one Another aspect of the present invention, the first valve element and the second valve element by an actuator and a valve element biasing device operated so that compared to an exhaust gas flow rate ratio control valve, which separates the first valve element and the second valve element by separate Actuators and separate valve element biasing devices actuated Number of components and man hours for assembly can be reduced can, with which a cost reduction is realized.

According to one Another aspect of the present invention includes the exhaust gas flow rate ratio control valve a first inlet opening for Introducing the exhaust gas from the first exhaust gas duct of the exhaust gas heat exchanger, a second opening for introducing the exhaust gas from the second exhaust duct of the bypass tube, a normally open first valve element, which is an open area the first opening a normally closed second valve element, which is an open area the second opening sets, and a mixing chamber for mixing the exhaust gas high temperature and the low temperature exhaust gas inside thereof. Through a such structure in the exhaust gas flow rate ratio control valve the low temperature exhaust gas, which from the first exhaust duct of the exhaust gas heat exchanger through the first opening is introduced into the mixing chamber, and the high temperature exhaust gas, which from the second exhaust duct of the bypass pipe through the second introducing opening is introduced into the mixing chamber, are mixed.

According to a further aspect of the present invention, the exhaust gas recirculation flow rate control valve includes a connecting channel which communicates with the exhaust gas heat exchanger via the first inlet opening and also communicates with the bypass pipe via the second inlet opening, a valve element which regulates an opening area of the connecting channel Actuator that drives a valve element in the valve opening direction and a valve element biasing device that biases the valve element in the valve closing direction. With such a structure, the exhaust gas, which is cooled inside the exhaust gas heat exchanger, flows into the inside of the communication passage of the exhaust gas recirculation flow rate control valve, and therefore it is possible to control the internal components of the exhaust gas recirculation flow rate To protect ten control valve, whereby the control response sensitivity of the exhaust gas recirculation flow rate control valve can be improved.

According to one Another aspect of the present invention is the exhaust gas cooling device constructed so that the exhaust gas heat exchanger and the bypass tube parallel and close to each other in the middle of the Exhaust gas recirculation duct for returning a part of the exhaust gas from the internal combustion engine to the intake side are. Such a structure can in comparison to the state of the Technology in which a heat exchanger and a bypass tube are arranged apart from each other, the structure the exhaust gas cooling device be made smaller. Accordingly, the Construction of the pipeline simplified and assembly of the exhaust gas cooling device can be simplified and therefore the assembly ability the exhaust gas cooling device improved on a vehicle.

According to one Another aspect of the present invention has the bypass tube in Essentially the same size as one Cylinder direction size of the exhaust gas heat exchanger and is parallel to and close to from the exhaust gas heat exchanger arranged. Furthermore, for the bypass tube is a bellows section with a bellows shape, which in the The cylinder direction of the bypass tube can be extended and retracted, intended. With such a structure, the difference of thermal expansion between the exhaust gas heat exchanger, which by cooling the high temperature exhaust gas with the cooling water a low temperature section is, and the bypass tube, which by direct flow through the High temperature exhaust gas becomes a high temperature section be taken up by the bellows section. Accordingly it is possible, the exhaust gas cooling device to provide, which shows excellent durability.

According to one further aspects of the present invention are in the middle of the Exhaust gas recirculation duct, which to return a Part of the exhaust gas is provided from the internal combustion engine to the intake side is the exhaust gas heat exchanger that Bypass pipe and the exhaust gas flow rate ratio control valve integrally formed by directly connecting these components in series. Because an exhaust gas recirculation flow pipe (Pipeline), which includes the exhaust gas heat exchanger and the exhaust gas flow rate ratio control valve connects, and an exhaust gas recirculation flow tube (Pipeline) connecting the bypass pipe and the exhaust gas flow rate ratio control valve, unnecessary the number of components can be reduced. Accordingly, the Installation characteristics of the exhaust gas heat exchanger and the exhaust gas flow rate ratio control valve be improved, or the assembly property of the bypass tube and the exhaust gas flow rate ratio control valve can be improved. Furthermore, a channel length of the exhaust gas recirculation channel greatly shortened and therefore the pipeline construction can be simplified with which the assembly ability the exhaust gas cooling device is improved on a vehicle. Furthermore, by integral Form the exhaust gas heat exchanger and the exhaust gas flow rate ratio control valve by directly connecting these components in series in the middle of the exhaust gas recirculation duct the heat through the exhaust gas heat exchanger cooled Exhaust gas efficiently transferred to the exhaust gas flow rate ratio control valve, and therefore it is possible the internal components of the exhaust gas flow rate ratio control valve to cool whereby the internal components of the exhaust gas flow rate ratio control valve from warmth of the exhaust gas protected can be. Accordingly it is possible, the control response sensitivity of the exhaust gas flow rate ratio control valve to improve.

According to one further aspects of the present invention are in the middle of the Exhaust gas recirculation duct to return a Part of the exhaust gas of the internal combustion engine is the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve integrally formed by directly connecting these components in series. There an exhaust gas recirculation flow tube (Pipeline) which the exhaust gas flow rate ratio control valve and connects the exhaust gas recirculation flow rate control valve unnecessary the number of components can be reduced. Accordingly, the Installation characteristic of the exhaust gas flow rate ratio control valve and of the exhaust gas recirculation flow rate control valve be improved. Furthermore, a channel length of the exhaust gas recirculation channel greatly shortened and therefore the construction of the pipeline can be simplified be, making the assembly ability the exhaust gas cooling device is improved on a vehicle. Furthermore, the irregularities the exhaust gas temperature between the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve are suppressed, and the channel length of the exhaust gas recirculation duct is shortened and therefore it is possible to Control response sensitivity of the exhaust gas flow rate ratio control valve and the EGR rate control valve to improve.

According to another aspect of the present invention, the inner components of the exhaust gas flow rate ratio control valve and the inner components of the exhaust gas recirculation flow rate control valve are accommodated and held inside a housing. With such a structure, it is possible to directly connect the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve Integrally forming components in series, and at the same time, the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve allow the one housing to be shared.

According to one further aspects of the present invention are in the middle of a Cooling water circulation channel which is the cooling water in the internal combustion engine in the order of the exhaust gas heat exchanger, of the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve circulates, the exhaust gas heat exchanger, the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve integrally formed by directly connecting these components in series. Accordingly a cooling water pipe, which is the exhaust gas heat exchanger and the exhaust gas flow rate ratio control valve connects, and a cooling water pipe, which is the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve connects, unnecessarily and therefore the number of components can be reduced. Accordingly, since the channel length of the Cooling water circuit channel strong shortened can be simplified, the construction of the cooling water pipe be, making the assembly ability the exhaust gas cooling device is improved on a vehicle. Furthermore, by direct introduction of the cooling water into the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve from the exhaust gas heat exchanger the exhaust gas passing through the inside of the exhaust gas flow rate ratio control valve flows, the exhaust gas flowing through the interior of the exhaust gas recirculation flow rate control valve, the internal components of the exhaust gas flow rate ratio control valve and the internal components of the exhaust gas recirculation flow rate control valve of the cooling water chilled become.

According to one Another aspect of the present invention is in a housing which the internal components of the exhaust gas flow rate ratio control valve and houses the internal components of the exhaust gas recirculation flow rate control valve and holds, a cooling water channel, which is part of the cooling water circuit channel forms on an inner component side of the exhaust gas flow rate ratio control valve and on an inner component side of the exhaust gas recirculation flow rate control valve with respect to Exhaust gas recirculation duct educated. Furthermore, the exhaust gas heat exchanger is on the inner component side of the exhaust gas flow rate ratio control valve and on the inner component side of the exhaust gas recirculation flow rate control valve with respect to Bypass channel arranged. With such a structure, it is through Cool of the housing by means of the one introduced directly into the interior of the cooling water duct from the exhaust gas heat exchanger cooling water possible, the internal components of the exhaust gas flow rate ratio control valve and the internal components of the exhaust gas recirculation flow rate control valve cool. Accordingly it is possible, the internal components of the exhaust gas flow rate ratio control valve and the inner components of the exhaust gas recirculation flow rate control valve Warmth of To protect exhaust gas and therefore it is possible the control response sensitivity of the exhaust gas flow rate ratio control valve and the EGR flow rate control valve improve.

According to one Another aspect of the present invention is in the housing which the internal components of the exhaust gas flow rate ratio control valve and houses the internal components of the exhaust gas recirculation flow rate control valve and holds, a cooling water channel, which is part of the cooling water circuit channel forms on an inner component side of the exhaust gas flow rate ratio control valve and on an inner component side of the exhaust gas recirculation flow rate control valve with respect to the Exhaust gas recirculation duct educated. There are also heat transfer fins inside the cooling water circuit channel in the housing trained and therefore it is possible the heat the housing, which due to the exhaust gas flowing through the interior of the housing the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve contains gets a high temperature to transfer to the cooling water, which is inside the cooling water channel circulated. Accordingly it is possible, the internal components of the exhaust gas flow rate ratio control valve and the internal components of the exhaust gas recirculation flow rate control valve by means of the cooling water to cool. On this way it is possible the internal components of the exhaust gas flow rate ratio control valve and the internal components of the exhaust gas recirculation flow rate control valve from warmth to protect the exhaust gas, and therefore it is possible the control response sensitivity of the exhaust gas flow rate control valve and the EGR flow rate control valve improve.

According to another aspect of the present invention, according to an operating state of the internal combustion engine detected by an operating state detection device or an exhaust gas temperature detected by an exhaust gas temperature detection device, a valve opening degree of the exhaust gas flow rate ratio control valve and a valve opening degree of the exhaust gas recirculation flow rate control valve are controlled continuously or stepwise, whereby the temperature and the total flow rate of the exhaust gas , which is returned from the exhaust gas recirculation duct into the intake duct, can be optimized. With such a structure, it is possible to control the temperature and the total flow rate of the exhaust gas optimized from the exhaust gas recirculation duct is returned to the intake duct. Accordingly, for example, in normal operation, by returning the exhaust gas into the intake passage after cooling the exhaust gas through the exhaust gas heat exchanger, it is possible to output nitrogen oxide (NOx) without a lower output of the engine and a lower operability of the engine, and at the same time the output amount of tiny ones Effectively reduce particles (particle matter: PM). Further, it is possible to recirculate the exhaust gas into the intake passage while maintaining the high temperature during the cold season, and therefore it is possible to achieve the sufficient idle effect on the intake air, which can prevent white smoke generation during the cold season ,

According to one Another aspect of the present invention is when starting the Operating in a cold atmosphere, i.e. when the temperature of the cooling water in the internal combustion engine lower than a first predetermined value is the valve opening degree of the Exhaust gas flow rate ratio control valve controlled to open the second valve element. Through one Process, the second inlet opening is opened and therefore most of the exhaust gas flows, which flows inside the exhaust gas recirculation channel Bypassing the exhaust gas heat exchanger the bypass tube. Accordingly, the Start operating in a cold atmosphere, the exhaust gas of high temperature returned to the suction side so that it possible is to achieve the sufficient idle effect, and therefore the sensitivity to ignition improved in the internal combustion engine when starting operation in the cold atmosphere, causing the generation white Smoke during suppressed the cold season can be. Furthermore, after performing the idle operation of the Internal combustion engine, i.e. when the temperature of the cooling water higher in the internal combustion engine as a second predetermined value by controlling the valve opening degree of the exhaust gas flow rate ratio control valve the first valve element opened and the second valve element closed. Through such a process flows the total flow rate of the exhaust gas flowing inside the exhaust gas recirculation flow passage the exhaust gas heat exchanger. Accordingly, the Temperature of the exhaust gas passing through the interior of the exhaust gas recirculation channel flows, is reduced and a volume of the exhaust gas is reduced. Accordingly it is possible, the generation of nitrogen oxide (NOx) by lowering the combustion temperature the fuel inside the engine without reducing to effectively reduce an output of the internal combustion engine.

According to one Another aspect of the present invention is by performing feedback control the valve opening degree of the Exhaust gas flow rate ratio control valve based on the temperature deviation between a current exhaust gas temperature and a target value so that the exhaust gas temperature detection device recorded current exhaust gas temperature essentially with the corresponding the setpoint set to the load state of the internal combustion engine corresponds, no way, that the temperature of the exhaust gas passing through the interior of the exhaust gas recirculation duct flows, assumes an abnormally low value compared to the target value. Accordingly, a The combustion state of the internal combustion engine improves and the speed of the internal combustion engine is stabilized. Furthermore, by performing the Feedback control the degree of valve opening of the exhaust gas flow rate ratio control valve based on the temperature deviation between the current exhaust gas temperature and the setpoint no way that the temperature of the exhaust gas passing through the interior of the exhaust gas recirculation duct flows, assumes an abnormally high value compared to the target value. Accordingly there is no way, that a return flow rate of the exhaust gas, which is a part of the exhaust gas in the internal combustion engine which flows from the exhaust duct into the intake duct, or an EGR ratio, which is a relationship the EGR flow rate in terms of a fresh amount of intake air becomes insufficient, and therefore can the deterioration of the emission of the internal combustion engine can be suppressed.

1 10 is a partial cross-sectional view of the entire structure of an EGR module in which an exhaust gas cooling device, an exhaust gas flow rate ratio control valve, and an exhaust gas recirculation flow rate control valve are integrally formed (first embodiment).

2 Fig. 13 is a structural view of the entire structure of an exhaust gas recirculation device for a diesel engine (first embodiment).

3 14 is a cross-sectional view of the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve (first embodiment).

4A 14 is a cross-sectional view of the main construction of the EGR module, and 4B is an enlarged view of a section A in 4A ,

5 FIG. 12 is a schematic diagram for explaining the overall structure of an EGR cooling device according to the third embodiment of FIG present invention.

6 11 is a cross-sectional view of an EGR cooler in an EGR cooling device according to the third embodiment of the present invention.

7 Fig. 10 is a cross sectional view taken along line VII-VII in Fig 6 ,

8th FIG. 14 is a schematic diagram for explaining the overall structure of an EGR cooling device according to the fourth embodiment of the present invention.

A Task, a sophisticated control of an exhaust gas temperature in the Inside an exhaust gas recirculation duct perform and determining a first valve element on a heat exchanger side of an exhaust gas flow rate ratio control valve The following structure can prevent a build-up of adhesive will be realized. Nearby an exhaust gas heat exchanger and a downstream one An exhaust gas flow rate ratio control valve is provided on the side of a bypass pipe, which is a first inlet opening, which is an exhaust gas from the exhaust gas heat exchanger introduces a second inlet opening, which the exhaust gas from the Bypass pipe initiates a first valve element on the exhaust gas heat exchanger side, which is an opening area of the first discharge opening regulates, and a second valve element on the bypass tube side, which an opening area of the second discharge opening regulates, exhibits. When operation of an internal combustion engine stops is, the first valve element on the exhaust gas heat exchanger side of the exhaust gas flow rate ratio control valve open.

(First embodiment)

1 to 3 show the first embodiment of the present invention, wherein 2 is a representation of the overall structure of an exhaust gas recirculation device for a diesel engine.

The exhaust gas recirculation device of this embodiment is used in an internal combustion engine such as a diesel engine (hereinafter referred to as an engine 1 designated) used. The exhaust gas recirculation device contains an exhaust gas recirculation channel 4 which with an inside an exhaust pipe of the engine 1 trained exhaust duct 2 is connected, and leads part of an exhaust gas (exhaust gas recirculation gas: hereinafter referred to as EGR gas) in an intake duct formed within an intake pipe 3 back. The exhaust gas flows inside the exhaust duct 2 of the motor 1 , Inside the intake duct 3 of the motor 1 an intake air flows through an air filter 10 is filtered. In the middle of an exhaust gas recirculation flow pipe, which is the exhaust gas recirculation channel 4 forms this embodiment, ie between an exhaust gas recirculation flow pipe 5 , which is branched from the exhaust pipe, and an intake-side exhaust gas recirculation flow pipe 6 , which comes together with the intake pipe, is an EGR module 7 connected directly in series. The exhaust gas recirculation flow pipe on the exhaust side 5 This embodiment is connected to an exhaust manifold of the exhaust pipe. The intake-side exhaust gas recirculation flow pipe 6 is connected to an intake manifold or a surge tank of the intake pipe.

In the engine 1 an engine cooling water circuit (cooling water circuit channel) is provided, which circulates engine cooling water and the EGR module 7 supplies. This engine cooling water circuit contains a cooling water pipe 8th for supplying the engine cooling water in a circulating manner to a cooling water inlet pipe 11 of the EGR module 7 from a water jacket (not shown in the drawing) of the engine 1 , a cooling water pipe 9 for performing the circulation supply (return) of the engine cooling water from a cooling water outlet pipe 12 of the EGR module 7 via a cooler (not shown in the drawing) to the water jacket of the engine 1 , and a water pump (not shown in the drawing) that generates a circulation flow of the engine cooling water in the engine cooling water circuit. In this embodiment, by performing the heat exchange between the engine cooling water and an outside air through the radiator, it is possible for the engine cooling water to the engine's water jacket in a predetermined temperature range (for example, 75 ° C to 80 ° C) 1 recirculate.

The construction of the EGR module 7 this embodiment is briefly related to 1 to 3 explained. Here is 1 4 is an illustration of the overall structure of the EGR module in which an exhaust gas cooling device, an exhaust gas flow rate ratio control valve, and an exhaust gas recirculation flow rate control valve are integrally formed, and 3 FIG. 4 is an illustration of the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve.

The EGR module 7 of this embodiment is the exhaust gas cooling device (described later) that cools the EGR gas by performing heat exchange between the high temperature EGR gas and the low temperature engine cooling water and a valve housing 17 , which is directly connected to a downstream side of the exhaust gas cooling device in the flow direction of the EGR gas and the engine cooling water, wherein the EGR module 7 a part of the exhaust gas recirculation flow pipe of the exhaust gas return device and forms part of the cooling water pipe of the engine cooling water circuit.

First, the exhaust gas cooling device contains an exhaust gas heat exchanger (hereinafter referred to as an EGR gas cooler) 14 which makes the EGR gas equal to or lower than a desired exhaust gas temperature by performing heat exchange between the high temperature EGR gas which comes from inside the exhaust gas recirculation flow pipe 5 trained exhaust gas recirculation duct 4 is introduced, and the engine cooling water low temperature, which from the inside of the cooling water pipe 8th trained cooling water channel flows into the exhaust gas cooling device, cools, and a bypass pipe 15 or the like, which from inside the exhaust gas recirculation flow pipe 5 trained exhaust gas recirculation duct 4 EGR gas introduced to the EGR gas cooler 14 passes by.

With an upstream side of the EGR gas cooler in the flow direction of the exhaust gas 14 of this embodiment is a two-way connection section 13 integrally connected, which for direct connection of the EGR gas cooler 14 with a downstream end portion of the exhaust gas recirculation flow pipe 5 serves in series. Further, with a downstream side of the EGR gas cooler in the flow direction of the exhaust gas 14 a connecting section 16 integrally connected, which for direct connection of the EGR gas cooler 14 with an upstream end portion of the valve housing 17 serves in series. Furthermore, between the two-way connection section 13 and the connecting section 16 the bypass tube 15 parallel and close to the EGR gas cooler 14 arranged. The two-way connection section 13 , the EGR gas cooler 14 , the bypass tube 15 and the connecting section 16 have their exhaust side exposed to the EGR gas of 400 ° C to 500 ° C or more containing hydrosulfide, nitric acid, sulfuric acid, ammonium ions, acetic acid or the like and condensed water thereof, and therefore these elements are integrally soldered to a metal material (to Stainless steel), which shows excellent heat resistance and erosion resistance, whereby the exhaust gas cooling device can be integrally formed.

The EGR gas cooler 14 , which forms the main part of the exhaust gas cooling device, contains an angled tube-like housing 21 which is directly connected to the downstream end portion of the exhaust gas recirculation flow pipe 5 via the two-way connection section 13 is connected in series and directly to the upstream end portion of the valve housing 17 over the connecting section 16 is connected in series, as well as several exhaust pipes 22 that are inside the case 21 are included. The housing 21 contains the several exhaust pipes 22 inside of it, and a cooling water channel 23 , which circulates the engine cooling water, is in the range of several exhaust pipes 22 intended.

The housing 21 which is an outer shell of the EGR gas cooler 14 is formed by connecting two mold plates (metal plates) by soldering using a solder material such as copper or the like into an angled tubular shape, these two mold plates made of a metal material (e.g. stainless steel) with excellent heat resistance and erosion resistance, and are shaped into an approximately U-shaped cross-section in the plate thickness direction by means of a press. Further is at a left end portion of the housing 21 in the drawing a cooling water inlet pipe 11 which the engine cooling water from a water jacket of the engine 1 into the interior of the cooling water channel 23 can penetrate, provided while at a right end portion of the housing 21 in the drawing, a cooling water outlet section that the engine cooling water from the cooling water channel 23 over the connecting section 16 inside the valve body 16 takes, is provided. Here are several reinforcing ribs 24 to increase the boiling strength and the pressure resistance on the housing 21 formed at an equal distance so that the reinforcing ribs 24 protrude outwards.

Several exhaust pipes 22 are formed on a plurality of flattened pipes into which the EGR gas flows from an inside of the two-way connection section 13 trained EGR gas two-way section 30 is initiated. These exhaust pipes 22 are stacked in a plurality in the short diameter direction with a predetermined interval therebetween and extend in the long diameter direction so that the exhaust pipes 22 the entire length of the case 21 overlap in the cylinder direction. The EGR gas cooler is in this exemplary embodiment 14 to increase the boiling resistance of the engine cooling water, which through the interior of the cooling water channel 23 of the housing 21 flows, provided. In the EGR gas cooler 14 are the direction of flow of the engine cooling water inside the cooling water duct 23 of the housing 21 and the flow direction of the EGR gas inside the respective first exhaust gas passages 31 of the several exhaust pipes 22 set in the same direction (parallel flow).

Furthermore, the respective exhaust pipes 22 formed in a flattened tube shape. These respective exhaust pipes 22 are made as follows. A multi-tube construction is achieved by alternately stacking two form plates (metal plates), which have the excellent heat resistance and the show excellent erosion resistance, formed and press-molded in the same way as the housing 21 formed in an approximately U-shaped cross section. These shaped plates are then connected to one another by soldering using a solder material such as copper. Then inside the several exhaust pipes 22 , as described above, the first exhaust channels 31 , which form the exhaust gas cooling channels. Inside every first exhaust duct 31 internal fins (not shown in the drawing) are arranged with a rectangular waveform which improve the heat exchange performance between the EGR gas and the engine cooling water by increasing the heat transfer area with the EGR gas.

The bypass pipe 15 is an approximately cylindrical tube that is substantially the same size as the cylinder direction size of the housing 21 of the EGR gas cooler 14 , and is in parallel with and near the EGR gas cooler 14 arranged. The EGR gas is in the bypass pipe 15 from the EGR gas two-way section 30 of the two-way connection section 13 initiated. The bypass pipe 15 is in the same way as the case 21 by integrally connecting two mold plates (metal plates) made of a metal material (for example, stainless steel) exhibiting excellent heat resistance and erosion resistance, by soldering with a solder material such as copper into a cylindrical tube shape. Then the left end section (in the drawing) of the bypass tube 15 with a two-way connection section 13 connected in a state that the left end portion into the inside of a mounting hole with a circular hole shape, which in a core plate 34 of the two-way connection section 13 is trained, is used. Furthermore, the right end section (in the drawing) of the bypass tube 15 with a connecting section 16 connected in a state that the right end portion into the inside of a mounting hole with a circular hole shape, which in an inner partition 35 the connecting section 16 is trained, is used.

Furthermore, is inside the bypass tube 15 a second exhaust duct 32 formed which from inside the EGR gas two-way section 30 introduced EGR gas on the first exhaust duct 31 passes by. There is also an upstream end of the second exhaust passage 32 with the inside of the EGR gas two-way section 30 connected, and a downstream end of the second exhaust passage 32 is with the inside of a second exhaust duct 32b that is inside the connecting section 16 is formed, connected. Here is on the bypass tube 15 a bellows-like bellows section 36 integrally formed, which in the cylinder direction of the bypass tube 15 is stretchable and shrinkable.

The two-way connection section 13 forms an exhaust gas introduction connection portion for introducing the EGR gas from inside the exhaust gas recirculation passage 4 of the exhaust gas agitator flow pipe 5 and is from a container plate 33 and a core plate 34 built up. The two-way connection section 13 is directly with an upstream end portion of the housing 21 connected in the cylinder direction by soldering. Furthermore, the container plate 33 and the core plate 34 in the same way as the case 21 by joining shaped plates (metal plates) made of a metal material (for example, stainless steel) showing the excellent heat resistance and the excellent erosion resistance, by soldering using a solder material such as copper in predetermined shapes. Here, an interior space is formed which is formed by recess sections of the container plate 33 and the core plate 34 is surrounded, an inlet-side container section of the EGR gas cooler 14 for distributing or branching the inside of the EGR gas two-way section 30 flowed EGR gas to the respective first exhaust gas channels 31 ,

Then the interior works (inlet-side container chamber), which is from the container plate 33 and the core plate 34 is surrounded as an EGR gas two-way section 30 which is from inside the exhaust gas recirculation duct 4 the exhaust gas recirculation flow pipe 5 EGR gas introduced into the first exhaust duct 31 of the EGR gas cooler 14 and the second exhaust duct 32 of the bypass tube 15 with a predetermined flow rate ratio or the total flow rate from the inside of the exhaust gas recirculation channel 4 of the exhaust-side return flow pipe 5 introduced EGR gas in the first exhaust duct 31 of the EGR gas cooler 14 initiates. Here are in the core plate 14 Insert holes with an angled hole shape, with which (in the drawing) left end portions of the respective first exhaust gas channels 31 of the several exhaust pipes 32 are connected by soldering in a state that the left end portions are inserted into the insertion holes, the number of insertion holes being the number of the exhaust pipes 22 equivalent.

The connecting section 16 will be in the same way as the case 21 by molding a metal plate from a metal material (for example, stainless steel), which shows excellent heat resistance and erosion resistance, by a press into a predetermined shape. The connecting section 16 includes a mounting flange section 37 for directly connecting the downstream sections of the EGR gas cooler 14 and the bypass tube 15 in line with the valve body 17 , There is also an inner partition section 35 integral with the connecting portion 16 out forms. In the inner partition section 35 are insertion holes with an angular shape, into which (in the drawing) right end portions of the respective first exhaust gas passages 31 of the several exhaust pipes 22 are connected by soldering in a state that these right end portions are inserted into the insertion holes. The number of insertion holes corresponds to the number of exhaust pipes 22 ,

Here, the interior is formed by the valve housing 17 and the recess portion of the inner partition portion 35 is surrounded, an outlet-side container section (first exhaust duct) 31b of the EGR gas cooler 14 to get that from the respective first exhaust channels 31 to let incoming EGR gas bundle. Furthermore, the connection section forms 16 a cooling water channel 16 which is the cooling water outlet portion of the in the housing 21 trained cooling water channel 23 and the cooling water channel inside the valve housing 17 on one side in the drawing above the second exhaust duct 32b connects directly. Here contains the inner partition section 35 of this embodiment, an (in the drawing) upper partition wall section, which the cooling water channel 26 and the first exhaust duct 31b defined liquid-tight and airtight, and a (in the drawing) lower partition section, which the first exhaust duct 31b and the second exhaust duct 32b defined liquid-tight and airtight.

Next are on the valve body 17 of this embodiment, an exhaust gas flow rate ratio control valve 18 , which is a ratio between a flow rate of the EGR gas entering the interior of the respective first exhaust gas passages 31 of the EGR gas cooler 14 flows, and a flow rate of the EGR gas entering the inside of the second exhaust passage 32 of the bypass pipe flows, continuously regulates, an exhaust gas recirculation flow rate control valve (EGR control valve) 19 which is the total flow rate of EGR gas flowing through the valve body 17 flows, continuously regulates, and the like integrally attached. Furthermore, is on the valve housing 17 an EGR flow sensor 20 integrally attached. The EGR flow sensor 20 converts a valve opening degree (rotation angle) of the exhaust gas recirculation flow rate control valve 19 around and releases a lot of it into an intake air, which is inside the intake duct 3 flows, mixed EGR gas, that is, an EGR gas recirculation flow rate (EGR amount) into the inside of the intake passage 3 from the exhaust duct 2 to an engine control unit (engine control unit: hereinafter referred to as ECU) 100 out.

The valve housing 17 of this embodiment is through the exhaust gas flow rate ratio control valve 18 and the exhaust gas recirculation flow rate control valve 19 shared. Accordingly, are in the valve housing 17 , as in 1 and 3 shown, a first exhaust gas inlet channel 41 , in which the EGR gas from the first exhaust duct 31 of the EGR gas cooler 14 via the first exhaust duct 31b is initiated, a second exhaust gas inlet channel 42 , in which the EGR gas from the second exhaust duct 32 of the bypass tube 15 via the second exhaust duct 32b is initiated, an exhaust gas recirculation channel (mixing chamber) 43 for mixing the high temperature EGR gas and the low temperature EGR gas, a communication passage 45 which with the exhaust gas recirculation channel 43 via the exhaust gas recirculation duct 44 is connected, and an exhaust gas recirculation channel 46 , which the EGR gas into the interior of the inside of the intake-side exhaust gas recirculation flow pipe 6 trained exhaust gas recirculation duct 4 from the connecting channel 45 initiates, trained. The first exhaust gas inlet duct 41 , the second exhaust gas inlet duct 42 , the exhaust gas recirculation duct 43 , the exhaust gas recirculation duct 44 , the connecting channel 45 and the exhaust gas recirculation duct 46 form the exhaust gas recirculation channel 4 ,

Here is the exhaust gas recirculation channel 43 constructed so that the EGR gas from the first exhaust gas inlet duct 41 through the first opening 51 into the exhaust gas recirculation channel 43 is introduced and at the same time the EGR gas from the second exhaust gas inlet duct 42 via the second inlet opening 52 into the exhaust gas recirculation channel 43 is initiated. There is also the connecting channel 45 with the first exhaust channels 31 of the EGR gas cooler 14 via the first exhaust gas inlet duct 41 and the first introduction opening 51 connected, and at the same time the connection channel is 45 with the second exhaust channels 32 of the bypass tube 15 via the second exhaust gas inlet duct 42 and the second introduction opening 52 in connection. Furthermore, in a (in the drawing) lower end of the second exhaust gas inlet duct 42 trained opening portion a plug 47 attached.

Furthermore, is inside the valve housing 17 a cooling water channel 27 in which the engine cooling water from the cooling water outlet portion of the in the EGR gas cooler 14 trained cooling water channel 23 via the cooling water channel 26 is initiated. A cooling water inlet section of the cooling water channel 27 , which at a (in the drawing) left end portion of the cooling water channel 27 is formed is directly connected to the cooling water channel 26 the connecting section 16 connected. Furthermore, is at a (in the drawing) right end portion of the cooling water channel 27 a cooling water outlet pipe 12 provided which with the cooling water pipe 9 connected is. Here are the cooling water channel in this embodiment 23 of the EGR gas cooler 14 and the cooling water channel 27 of the valve housing 17 on an internal component (for example bearing 57 ) Side of the exhaust gas flow rate ratio control valve 18 and on an internal component (for example bearing 76 ) Exhaust gas recirculation flow rate control valve side 19 arranged, whereby the internal components can be cooled more easily by means of the engine cooling water.

Then the valve body 17 of this embodiment is integrally molded into a predetermined shape by cast aluminum or die-cast aluminum and by attaching to a downstream portion of the connection portion 16 the exhaust gas cooling device, which is integrally formed by soldering, by means of screws, not shown in the drawing, such as fastening screws or the like. In this case, there is a leakage of the engine cooling water from a connection section where the cooling water channel 26 the connecting section 16 and the cooling water channel 27 of the valve housing 17 are connected, a rubber seal (not shown in the drawing) between a (in the drawing) right end surface of the mounting flange portion 37 the connecting section 16 and a left end face (in the drawing) of the valve housing 17 assembled. Also, to prevent the EGR gas from leaking from a connection portion where the first exhaust passage 31b the connecting section 16 and the first exhaust gas introduction channel 41 of the valve housing 17 are connected to prevent and at the same time leakage of the EGR gas from a connecting section where the second exhaust duct 32b the connecting section 16 and the second exhaust gas introduction duct 42 of the valve housing 17 are connected to prevent metal seals (not shown in the drawing) each between a (in the drawing) right end surface of the mounting flange portion 37 the connecting section 16 and a left end face (in the drawing) of the valve housing 17 assembled.

If this is a metal material which is integral with the connecting portion 16 can be soldered as the material of the valve housing 17 is used, the valve housing can also be carried out when performing the integral soldering of the exhaust gas cooling device 17 be connected by soldering. In this case, after performing the integral soldering, the respective components of the exhaust gas flow rate ratio control valve 18 , the respective components of the exhaust gas recirculation flow rate control valve 19 and the respective components of the EGR flow sensor 20 on the valve housing 17 assembled. Here, the cooling water channel 27 of the valve housing 17 to a degree of internal components (for example bearings 57 ) of the exhaust gas flow rate ratio control valve 18 , the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 and a drive motor (described later) for the purpose of protecting the internal components (e.g. bearings 57 ) of the exhaust gas flow rate ratio control valve 18 and the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 be provided before heat of the EGR gas.

The exhaust gas flow rate ratio control valve 18 contains a first and a second inlet opening 51 . 52 which inside the valve housing 17 are formed, a double-plate valve 53 made of metal, which the opening surfaces of the first and second inlet opening 51 . 52 regulates a valve stem made of metal (stem-like section) 54 , which is integral with the double poppet valve in the axial direction 53 is operated back and forth, a valve element drive device (described later) for driving the double-poppet valve 53 and the valve stem 54 in the upward direction in the drawing, and a valve element biasing device (e.g. spring) 55 which the double plate valve 53 and the valve stem 54 biased downward in the drawing. Here is the second opening 52 inside a valve plate 56 made of metal.

The double plate valve 53 of this embodiment is formed in an approximately disc-like shape using a metal material exhibiting excellent heat resistance and erosion resistance such as stainless steel or the like, and is made of a normally open first valve element (first flange portion, valve) 61 , which has an opening area of the first introduction opening 51 regulates a normally closed second valve element (second flange section, valve) 62 , which has an opening area of the second introduction opening 52 regulates a cylindrical connecting section 63 , which the first and the second valve element 61 . 62 connects, and the like built. The double plate valve 53 is fitted over an outer periphery of a valve holding portion, which is on a (in the drawing) lower end side of the valve stem 54 is formed, and is integral with the valve stem 54 educated. Here the double-poppet valve has 53 this embodiment has the structure that even if the second valve element 62 on the side of the bypass tube 15 is completely open, the first valve element 61 on the side of the EGR gas cooler 14 is not completely closed. If the second valve element 62 of the double plate valve 53 on the side of the bypass tube 15 is completely closed, the second valve element also rests 62 on the second valve seat on the (in the drawing) upper end side, which consists of the approximately circular valve seat 56 is formed, and therefore the second introduction port 52 hermetically sealed.

The valve stem 54 this embodiment is slidable inside an inner structure partly (e.g. warehouse 57 ) arranged, which in a bearing section on the (in the drawing) left side of the valve housing 17 is recorded and held. In the same way as the double plate valve 53 is the valve stem 54 integrally formed of a metal material such as stainless steel or the like, which shows the excellent heat resistance and the excellent erosion resistance, with the valve stem 54 includes a valve holding section which holds the double poppet valve 53 holds and fixes using a fastener such as welding. Here is a sleeve of large diameter 58 on an outer circumference of the valve stem 54 attached. Furthermore, is in the valve housing 17 a sleeve of small diameter 59 , which in an inner diameter of the sleeve of large diameter 58 is fitted, attached. Due to the provision of the large diameter sleeve 58 and the small diameter sleeve 59 the tiny particles contained in the EGR gas penetrate inside between an outer periphery of the valve stem 54 and an inner circumference of the bearing 57 trained bearing sliding portion, whereby the formation of the deposit is suppressed. Accordingly, it is possible to prevent a disadvantage that the deposit in a tiny gap between the outer periphery of the valve stem 54 and the inner circumference of the bearing 57 is defined, and therefore the valve stem 54 on a sliding surface of the bearing 57 adheres, causing the double poppet valve 53 of the exhaust gas flow rate ratio control valve 18 cannot carry out the quiet opening / closing process.

The valve element drive device, which is the double-plate valve 53 and the valve stem 54 of the exhaust gas flow rate ratio control valve 18 of this embodiment is a negative pressure actuator using negative pressure and the first valve element 61 on the side of the EGR gas cooler 14 from the double plate valve 53 drives in the valve closing direction and at the same time the second valve element 62 on the side of the bypass tube 15 from the double plate valve 53 drives in the valve opening direction. Here, the actuator working with negative pressure moves a membrane 64 by controlling the pressure difference between a vacuum chamber 65a between a housing 60 and a thin film membrane 64 is formed, and an atmospheric pressure chamber 65 by means of an electromagnetic or an electrically operated vacuum control valve 18a , which causes the stroke of the double-plate valve 53 and the valve stem 54 is generated in the axial direction. On a middle section of the membrane 64 is through two pressure plates 66 pressed to attach an upper end portion (in the drawing) of the valve stem 54 by a fastening device such as caulking.

Furthermore, the vacuum chamber 65a configured to a vacuum from a vacuum source, such as a vacuum pump, via the electromagnetic or electrically operated vacuum control valve 18a to recieve. Here is the electromagnetic or electrically operated vacuum control valve 18a able to get inside the vacuum chamber 65a introduced negative pressure change continuously. Furthermore, a vacuum in the intake pipe can be used as a vacuum source. There is also a feather 55 inside the vacuum chamber 65a arranged. That feather 55 is a spring (valve element biasing device) which is used to bias the first valve element 61 in the valve opening direction and at the same time the biasing of the second valve element 62 in the valve closing direction by pressing the membrane 64 to the side of the atmospheric pressure chamber 65 serves. Here are in the exhaust gas flow rate ratio control valve 18 this embodiment between the bearing portion of the valve housing 17 and the upper end side portion (in the drawing) of the valve stem 54 a cylindrical stop element 68 and a cylindrical guide 69 for holding an oil seal 67 attached.

The exhaust gas recirculation flow rate control valve 19 contains a connection channel 45 which is inside the valve body 17 is arranged, a valve made of metal (valve element) 71 , which has an opening area of the connecting channel 45 regulates a metal valve stem 72 which is integral with the valve 71 is operated in the direction of rotation, a valve element drive device (described later) which the valve 71 and the valve stem 72 drives in the valve opening direction, and a valve element biasing means (for example spring) which the valve 71 and the valve stem 72 preloaded in the valve closing direction. Here is the connection channel 45 inside the metal, circular cylindrical tube (nozzle) 74 formed which in the interior of the valve housing 17 is fitted.

The valve 71 of this embodiment is formed into an approximately disk-like shape using a metal material exhibiting excellent heat resistance and erosion resistance, such as stainless steel. A sealing ring 75 , which with an inner wall surface (flow channel surface) of the nozzle 74 can come into sliding contact is on an outer peripheral portion of the valve 71 kept near the fully open position of the valve. The sealing ring 75 is also using a metal material showing excellent heat resistance and erosion resistance, such as stainless steel way like the valve 71 shaped into an approximately cylindrical shape. The valve stem 72 can be moved inside an internal component (e.g. bearing 76 ) attached, which in a bearing holder section (right side in the drawing) of the valve housing 17 is recorded and held. The valve stem 72 is using a metal material showing excellent heat resistance and erosion resistance, such as stainless steel, in the same way as the valve 71 integrally formed. The valve stem also has 72 a valve holding section for holding and fixing the valve 71 attached to it by means of a fastening device such as welding. In order to suppress a phenomenon that minute particles contained in the EGR gas enter the inside of the bearing sliding portion, which is between an outer periphery of the valve stem 72 and an inner circumference of the bearing 76 is formed, and form a deposit, here is a guide 77 on the outer periphery of the valve stem 72 attached. With such a structure, it is possible to overcome a disadvantage that the deposit penetrates into the minute gap between the outer periphery of the valve stem 72 and the inner circumference of the bearing 76 is defined, and therefore the valve stem 72 on the sliding surface of the bearing 76 adheres, causing the valve to open / close smoothly 71 of the exhaust gas recirculation flow rate control valve 19 could not be achieved.

Furthermore, the valve drive device of the exhaust gas recirculation flow rate control valve 19 constructed from an electrically operated actuator from a drive unit and drives the valve 71 by rotating the valve stem 72 in a valve opening direction. At an upper end portion of the valve stem (in the drawing) 72 of this embodiment, a caulking attachment portion is integrally formed which has a valve-side gear 78 , which forms a component of a power transmission mechanism, and a rotor 79 which is a component of the EGR flow sensor 20 forms, attached to it by means of a fastening device such as caulking or the like.

The drive unit is designed to a drive motor (not shown in the drawing), which the valve 71 and the valve stem 72 of the exhaust gas recirculation flow rate control valve 19 drives in the direction of rotation, and a power transmission mechanism (a reduction gear mechanism in this embodiment) for transmitting a rotational force of the drive motor to the valve stem 72 of the exhaust gas recirculation flow rate control valve 19 to contain. The reduction gear mechanism is provided for reducing a speed of a motor shaft of the drive motor to a predetermined reduction ratio and includes a pinion (not shown in the drawing) which is fixed to an outer periphery of the motor shaft of the drive motor, a reduction gear (not shown in the drawing) which engages with the pinion and is driven by the pinion, and a valve-side gear 78 , which is in engagement with the reduction gear and is driven by the reduction gear.

The valve-side gear 78 is integrally molded in a predetermined roughly ring shape using, for example, a synthetic resin material. On an outer peripheral portion of the valve-side gear 78 is a gear section 80 , which is in engagement with the reduction intermediate gear, integrally formed. Here is in the exhaust gas recirculation flow rate control valve 19 this embodiment a spring 73 between a lower wall surface of a gear housing section or a motor housing section 81 , which is integral with an (in the drawing) upper end side of the valve housing 17 is formed, and a (in the drawing) lower end side of the valve-side gear 78 attached. There is also a rotor 79 made of an iron-directed metal material (magnetic material) on an inner peripheral portion of the valve-side gear 78 formed by insert molding.

The EGR flow sensor 20 12 is a rotation angle detection device which shows a valve opening degree of the exhaust gas recirculation flow rate control valve 19 , ie an angle of rotation of the valve 71 and the valve stem 72 detected. The EGR flow sensor 20 is from the above rotor 79 , a split permanent magnet 91 , which is a magnetic field generation source, a split yoke (not shown in the drawing) which is formed by the permanent magnet 91 is magnetized, several Hall elements (non-contact rotation angle detection elements), which are integral on one side of a sensor cover 92 , which is made of an electrically insulating synthetic resin, in a state that the Hall elements are the permanent magnet 91 are facing, are arranged, connections 94 which are the Hall elements 93 and an external ECU 100 electrically connect, and a stator 95 which is made of an iron-directed metal material (magnetic material) which has magnetic fluxes on the Hall elements 93 focused, built. Here is between the bearing section of the valve housing 17 of this embodiment and an upper end side portion (in the drawing) of the valve stem 72 of the exhaust gas recirculation flow rate control valve 19 an oil seal 96 attached.

In the ECU 100 is a microcomputer one known construction provided which is constructed by including functions of a CPU which executes control processing and arithmetic processing, a memory device (memory such as ROM, RAM and the like) which stores various programs and data, an input circuit, an output circuit and the like , Furthermore, the ECU 100 designed such that when an ignition switch (not shown in the drawing) is switched on (IG / ON), for example based on a control program stored in the memory, the valve opening degree of the double-poppet valve 53 of the exhaust gas flow rate ratio control valve 18 and the valve opening degree of the valve 71 of the exhaust gas recirculation flow rate control valve 19 can be controlled electronically. Here is the ECU 100 also configured so that when the ignition switch is turned off (IG / OFF), the above-mentioned control is forcibly ended based on the control program stored in the memory.

Here, sensor signals from the various sensors are designed so that they correspond to those in the ECU 100 integrated microcomputer after undergoing A / D conversion by an A / D converter. There is also a speed sensor with the microcomputer 101 , which detects an engine speed (also referred to as engine speed NE), as an operating state detection device for detecting an operating state of the engine 1 , an acceleration opening degree sensor (engine load detection device) 102 , which detects an acceleration opening degree (ACCP) according to a depression amount of an accelerator pedal, an intake temperature sensor 103 which is a temperature one in the respective cylinder of the engine 1 through the intake pipes intake air (intake temperature) detected, an intake air quantity sensor (air flow meter, not shown in the drawing), which a flow rate (intake air quantity) into the respective cylinder of the engine 1 intake air sucked through the intake pipe, and a cooling water temperature sensor (cooling water temperature detecting means, not shown in the drawing) that detects an engine cooling water temperature (THW), and the like.

Furthermore, with the microcomputer, the above-mentioned EGR amount sensor 20 and an exhaust gas temperature sensor (exhaust gas temperature detection device) 104 , which is a temperature of the inside of the exhaust gas recirculation channel 4 of the intake-side exhaust gas recirculation flow pipe 6 to the inside of the intake duct 3 after flowing out of the EGR module 7 flowing EGR gas detected, connected. Here, the exhaust gas temperature sensor 104 a sensor signal fine voltage signal) corresponding to a temperature of the EGR gas after mixing the EGR gas, which is inside the respective first exhaust gas channels 31 of the EGR gas cooler 14 flows, and the EGR gas, which is inside the second exhaust channels 32 of the bypass tube 15 flows to the ECU 100 out.

(Control method of embodiment 1)

Next, the control method of the exhaust gas recirculation device of this embodiment will be briefly related to FIG 1 to 3 explained.

The ECU 100 is designed to operate solenoid-operated valves of injectors (for example, electromagnetic fuel injectors) that correspond to respective cylinders of the engine 1 are attached to control. That is, a basic injection quantity (Q) is based on that by the speed sensor 101 detected engine speed (NE) and that by the accelerator opening sensor 102 detected acceleration opening degree (ACCP) is calculated. Then, a command injection amount (a target injection amount QFIN) is calculated by adding an injection correction amount obtained by taking the engine cooling water temperature (THW), a fuel temperature (THF), and the like into account in the basic injection amount (Q). Furthermore, the ECU 100 configured to calculate a command injection period (TFIN) based on the engine speed (NE) and the command injection amount (QFIN).

The ECU also leads 100 in this embodiment, by the ECU 100 Commanded (determined) target EGR gas temperature (target value) and by the exhaust gas temperature sensor 104 detected EGR gas temperature (measured value) substantially equal to each other, a feedback control of a drive current value of the valve element drive device for driving the double-plate valve 53 and the valve stem 54 of the exhaust gas flow rate ratio control valve 18 , in particular a drive current value of the electromagnetic or electrically operated vacuum control valve 18a based on a known proportional-integral-differential control (PID control) or a known proportional-integral control (PI control). Here, the target EGR gas temperature is determined so that the operating state of the engine 1 based on at least information from sensor signals from the speed sensor 101 , the accelerator opening degree sensor 102 , the exhaust gas temperature sensor 104 and the like and the command injection amount (QFIN) is detected and then an optimal value of the target EGR gas temperature based on the current operating state of the engine 1 is determined. Here, it is desirable that control of the control command value (drive current value) to the electromagnetic cal or electrically operated vacuum control valve 18a is carried out by means of a switch-on control. Ie the ECU 100 applies the switch-on control, in which a switch-on / switch-off rate of the control pulse signals per unit of time (excitation rate or switch-on ratio) is set in accordance with the temperature deviation between the target EGR gas temperature and the detected EGR gas temperature and the valve opening degree (angle of rotation) of the double-plate valve 53 of the exhaust gas flow rate ratio control valve 18 is continuously changed.

The ECU also leads 100 in this embodiment, by the ECU 100 commanded (determined) command EGR amount (target valve opening degree) and that by the EGR amount sensor 20 substantially equalize detected EGR amount (actual valve opening degree), a feedback control of a drive current value of the drive motor for rotating the valve 71 and the valve stem 72 of the exhaust gas recirculation flow rate control valve 19 based on a known proportional-integral-differential control (PID control) or a known proportional-integral control (PI control). Here, the command EGR amount is determined so that the operating state of the engine 1 based on sensor signals from the EGR quantity sensor 20 , the speed sensor 101 , the intake temperature sensor 103 , the intake air amount sensor, and the like and on the command injection amount (QFIN), and then an optimal value of the commanded EGR amount based on the current operating state of the engine 1 , that is, the optimum value of the commanded EGR amount, which is the generation amount of nitrogen oxide (NOx) in the exhaust gas while suppressing a decrease in the output of the engine 1 and reducing engine operability 1 can reduce, is determined. Here, it is desirable that the control command value (drive current value) to the drive motor is controlled by a power-up control. Ie the ECU 100 applies the switch-on control, in which a switch-on / switch-off rate of the control pulse signals per unit of time (excitation rate or switch-on ratio) is set in accordance with the deviation between the commanded EGR quantity (target valve opening degree) and the measured EGR quantity (actual valve opening degree) and the valve opening degree (angle of rotation) of the valve 71 of the exhaust gas recirculation flow rate control valve 19 is continuously changed.

Next, an example of the control method of the valve opening degree of the double poppet valve 53 of the exhaust gas flow rate ratio control valve 18 according to the operating state of the engine 1 explained. First, when the engine is operating 1 is stopped to prevent the generation of a phenomenon that the minute particles contained in the exhaust gas on the surface of the first valve element 61 on the side of the EGR gas cooler 14 adhere and form an adhesive deposit on the surface, the excitation of the electromagnetic or the electrically operated vacuum control valve 18a stopped the first valve element 61 of the exhaust gas flow rate ratio control valve 18 on the side of the EGR gas cooler 14 fully open and the second valve element 62 on the side of the bypass tube 15 to close completely. Through such an operation, when the engine is operating 1 is stopped, the first opening 51 which the exhaust gas into the interior of the exhaust gas recirculation channel (mixing channel) 43 on the intake side of the first exhaust ducts 31 inside the EGR gas cooler 14 initiates, releases (fully open), and the second opening 52 which the exhaust gas from the second exhaust gas channels 32 inside the bypass tube 15 into the interior of the exhaust gas recirculation duct 43 initiates on the intake side, blocked (completely closed). Ie if the operation of the engine 1 is stopped, the temperature of the EGR gas passing through the interior of the exhaust gas recirculation channel 4 for returning the EGR gas into the intake duct 3 of the intake pipe flows, set to a somewhat higher level.

Furthermore, when the operating state of the engine 1 when starting operation in a cold season, that is, when the engine cooling water temperature (THW) detected by the cooling water temperature sensor is lower than a first predetermined value (for example, 0 ° C) to achieve the sufficient idling effect on the intake air, the second valve element 62 on the side of the bypass tube 15 fully open. Even if the second opening 52 which the exhaust gas from the second exhaust duct 32 into the inside of the bypass tube 15 initiates, is fully open, opens the first valve element in this embodiment 61 on the side of the EGR gas cooler 14 the first opening 51 which the exhaust gas from the first exhaust gas channels 31 inside the EGR gas cooler 14 initiates, with a predetermined degree of opening or more. Ie the first valve element 61 on the side of the EGR gas cooler 14 is not closed completely and therefore the first valve element is at rest 61 not on the valve seat.

Furthermore, after the engine idles 1 is finished (after the engine is idling 1 ), i.e. when the engine cooling water temperature (THW) detected by the cooling water temperature sensor is higher than a second predetermined value (for example 80 ° C) higher than the first predetermined value, in order to reduce the generation of the nitrogen oxide (NOx) by lowering the combustion temperature of the fuel in the Combustion chambers of the respective cylinder of the engine 1 effectively reduce the excitation of the electromagnetic or electrically operated vacuum control valve 18a stopped so the first valve element 61 of the exhaust gas flow rate ratio control valve 18 on the side of the EGR gas cooler 14 fully open and the second valve element 62 on the side of the bypass tube 15 to close completely. Due to such an operation, the engine will idle 1 the temperature of the EGR gas passing through the interior of the exhaust gas recirculation channel 4 for returning the EGR gas into the intake duct 3 of the intake pipe flows, sufficiently low. In particular, the temperature of the EGR gas entering the intake duct 3 of the intake pipe is returned, for example about 120 ° C.

Furthermore, during a period of starting the engine idling 1 in the cold season, that is, when the cooling water temperature (THW) detected by the cooling water temperature sensor has a value in a temperature range from a temperature equal to or higher than the first predetermined value (for example, 0 ° C) to a temperature equal to or lower than the second specified value (for example 80 ° C) is set by the exhaust gas temperature sensor 104 EGR gas temperature recorded (temperature of the EGR module 7 flowed and into the interior of the intake duct 3 flowed EGR gas) essentially to the target EGR gas temperature, which corresponds to the operating state of the engine 1 is set to adjust, a feedback control with respect to the valve opening degree of the double-poppet valve 53 of the exhaust gas flow rate ratio control valve 18 by means of a known proportional-integral-differential control (PID control) or a known proportional-integral control (PI control). Accordingly, during the period from starting to idling the engine 1 in the cold season the temperature of the EGR gas, which passes through the interior of the exhaust gas recirculation channel 4 for returning the EGR gas into the intake duct 3 of the intake pipe flows, controlled according to the target EGR gas temperature. In particular, the temperature of the EGR gas entering the intake duct 3 of the intake pipe is returned, for example regulated to about 130 ° C to 300 ° C.

Here, during the period from starting to idling the engine 1 in the cold season the temperature of the exhaust gas changes depending on the engine load. In particular, when the engine load is low, the temperature of the exhaust gas becomes, for example, about 180 ° C, and when the engine load is medium, the temperature of the exhaust gas becomes, for example, about 350 ° C. Accordingly, it is during the period from starting to idling the engine 1 in the cold season by optimizing the valve opening degree of the double-plate valve 53 of the exhaust gas flow rate ratio control valve 18 Depending on the engine load, it is possible to control the EGR gas temperature to the target EGR gas temperature (for example about 130 ° C to 300 ° C).

Next, the operation of the exhaust gas recirculation device of this embodiment will be related to FIG 1 to 3 explained.

(How the first one works Embodiment)

For example, if the intake valve is in the cylinder head of the engine 1 trained intake opening when starting the engine 1 , such as the diesel engine, is opened, the intake air through the air filter 10 is filtered into the intake manifold of the respective cylinder through the intake duct 3 , the throttle body and the surge tank of the intake pipe distributed and inside the respective cylinder of the engine 1 sucked. In the engine 1 the air is compressed to have a temperature higher than a temperature at which the fuel becomes combustible, and then a fuel under pressure is injected from an injector, thereby producing the combustion. Then the combustion gas, which is burned in the respective cylinders, from the in the cylinder head of the engine 1 trained exhaust ports and output through exhaust manifolds and the exhaust duct 2 the exhaust pipes are released to the outside.

Here, the electromagnetic or electrically operated vacuum control valve 18a drive current value supplied by the ECU 100 regulated so that the double poppet valve 53 of the exhaust gas flow rate ratio control valve 18 assumes a predetermined valve opening degree, the negative pressure is in the negative pressure chamber 65a initiated and the membrane 64 deviates according to the pressure difference between the vacuum chamber 65a and the atmospheric pressure chamber 65 out and the valve stem 54 is lifted up by a specified stroke dimension in the drawing. Through such an operation, the first valve element 61 of the double plate valve 53 on the side of the EGR gas cooler 14 driven in the valve closing direction and therefore the opening area of the inside of the valve housing 17 trained first introduction opening 51 regulated to a predetermined valve opening degree. At the same time, the second valve element 62 of the double plate valve 53 on the side of the bypass tube 15 driven in the valve opening direction and therefore the opening area of the inside of the valve housing 17 trained second inlet opening 52 regulated to a predetermined valve opening degree. Accordingly, a flow rate of the EGR gas which is inside the first exhaust gas passages 31 of the EGR gas cooler lers flows, and a flow rate of the EGR gas, which is inside the second exhaust duct 32 of the bypass tube 15 flows according to the operating state of the engine 1 and the temperature of the EGR gas optimized.

On the other hand, if the drive motor by the ECU 100 is excited so the valve 71 of the exhaust gas recirculation flow rate control valve 19 assumes a predetermined valve opening degree, the motor shaft of the drive motor is rotated. Then, due to the rotation of the motor shaft, the pinion is rotated and torque is transmitted to the reduction gear. Then the valve-side gear is turned by the rotation of the reduction gear 78 with the gear section 80 , which is in engagement with the reduction gear, rotated. Accordingly, the valve stem 72 , which is integral with the valve-side gear 78 is formed to rotate a predetermined angle of rotation and the valve 71 of the exhaust gas recirculation flow rate control valve 19 is turned in the direction that the valve 71 opens from the fully closed position to the fully open position (valve opening direction). Through such a process, the opening area of the connecting channel 45 which with the first exhaust channels 31 of the EGR gas cooler 14 through the first exhaust gas inlet duct 41 and the inlet opening 51 is connected and also with the second exhaust duct 32 of the bypass tube 15 through the second exhaust gas inlet duct 42 and the second introduction opening 52 is connected, regulated to a predetermined valve opening degree. Accordingly, the total flow rate of the EGR gas flowing through the exhaust gas recirculation passage 43 , the exhaust gas recirculation duct 44 , the connecting channel 45 and the exhaust gas recirculation duct 46 in the valve housing 17 flows, ie the total flow rate of the EGR gas which passes through the interior of the exhaust gas recirculation channel 4 for returning the EGR gas into the intake duct 3 of the intake pipe flows according to the operating state of the engine 1 and the temperature of the EGR gas can be optimized.

Accordingly, the EGR gas flows out of the exhaust passage 2 of the exhaust pipe in the exhaust gas recirculation duct formed in the exhaust gas recirculation flow pipe 4 is initiated through the interior of the EGR module 7 and inside the exhaust gas recirculation flow pipe 6 trained exhaust gas recirculation duct 4 into the interior of the intake duct 3 of the intake pipe and with the intake air from the air filter 10 mixed. Here, the EGR gas coming from the exhaust gas recirculation flow pipe 5 inside the EGR gas two-way section 30 of the two-way connection section 13 is introduced into the first exhaust gas channels with a predetermined flow rate ratio 31 of the EGR gas cooler 14 and the second exhaust duct 32 of the bypass tube 15 branched. The EGR gas, which is in the first exhaust gas channels 31 of the EGR gas cooler 14 flows, the heat exchange with the engine cooling water, which is inside the cooling water duct 23 of the EGR gas cooler 14 flows, subjected and is cooled with it. The EGR gas then flows through the first exhaust duct 31b the connecting section 16 into the interior of the first exhaust gas inlet duct 41 of the valve housing 17 , Then the EGR gas flows into the inside of the first exhaust gas introduction passage 41 flows through the first inlet opening 51 into the exhaust gas recirculation channel 43 ,

On the other hand, the EGR gas flows into the inside of the second exhaust passage 32 of the bypass tube 15 flows through the second exhaust duct 32b the connecting section 16 into the interior of the second exhaust gas inlet duct 41 of the valve housing 17 without undergoing heat exchange with the engine cooling water. Then the EGR gas flows into the second exhaust gas introduction channel 42 flows through the second inlet opening 52 into the exhaust gas recirculation channel 43 and then comes with the EGR gas that passes through the first inlet port 51 from the first exhaust channels 31 of the EGR gas cooler 14 into the exhaust gas recirculation channel 43 flows, mixes, and therefore the EGR gas is regulated to an optimal temperature. The EGR gas then flows through the exhaust gas recirculation channel 44 , the connecting channel 45 and the exhaust gas recirculation duct 46 into the intake-side exhaust gas recirculation flow pipe 6 ,

Furthermore, the engine cooling water flows, which the EGR gas inside the EGR gas cooler 14 cools, through the cooling water pipe 8th and the cooling water inlet pipe 11 of the EGR module 7 from the water jacket (not shown in the drawing) of the engine 1 in the cooling water channel 23 of the EGR gas cooler 14 and cools the EGR gas by removing heat from the EGR gas which is inside the first exhaust gas passages 31 of the EGR gas cooler 14 flows. Then, the engine cooling water flows out of the cooling water outlet portion of the cooling water duct 23 of the EGR gas cooler 14 into the interior of the cooling water channel 26 the connecting section 26 , Then the engine cooling water flows into the cooling water channel 26 flows into the cooling water channel 27 of the valve housing 17 and cools the valve body 17 whose temperature has risen to the high temperature due to the heat of the EGR gas. Then, the engine cooling water is circulated from the exhaust pipe 12 of the EGR module 7 through the radiator to the engine's water jacket 1 fed.

In normal operation, for example, the valve 71 the exhaust gas recirculation flow th control valve 19 opened with a suitable degree of opening and the first valve element 61 on the side of the EGR gas cooler 14 of the double plate valve 53 of the exhaust gas flow rate ratio control valve 18 opened so the second valve element 62 on the side of the bypass tube 15 open, causing all of the EGR gas contained in the inside of the exhaust gas recirculation flow pipe 5 trained exhaust gas recirculation duct 4 is initiated through the first exhaust duct 31 of the EGR gas cooler 14 to the intake duct 3 of the intake pipe is returned. By doing so, the EGR gas is sufficiently cooled by the engine cooling water. Accordingly, the EGR gas, which is at the low temperature and has the small volume, is mixed into the intake air, and therefore it is possible to reduce the generation of NOx by lowering the combustion temperature without reducing the output of the engine 1 effectively reduce.

Furthermore, for example, in the cold season the valve 71 of the exhaust gas recirculation flow rate control valve 19 opened with a suitable degree of opening, and both the first valve element 61 on the side of the EGR gas cooler 14 as well as the second valve element 62 on the side of the bypass tube 15 from the double plate valve 53 of the exhaust gas flow rate ratio control valve 18 are opened so that the EGR gas, which is in the inside of the exhaust gas recirculation flow pipe 5 Exhaust gas recirculation channel formed 4 is initiated with a predetermined flow rate ratio in the first exhaust duct 31 of the EGR gas cooler 14 or in the second exhaust duct 32 of the bypass tube 15 is branched, which optimizes the temperature of the EGR gas, and then the EGR gas is introduced into the intake duct 3 of the intake pipe returned. By doing so, the EGR gas can be returned in a state that the temperature of the EGR gas is kept in the relatively high state. Accordingly, it is possible to achieve the sufficient idling effect on the suction pump, and therefore the ignition sensitivity in the engine 1 improved, whereby the generation of white smoke can be prevented.

Furthermore, when the temperature of the intake air is lowered by cooling the EGR gas, there is a tendency that an output amount of NOx is reduced. However, in the operating state in which the engine 1 operating at the relatively low speed and the relatively low load when the EGR gas is cooled increases the output amount of the minute exhaust gas particles (particulate matter: PM). Accordingly, it is by controlling the first valve element 61 on the side of the EGR gas cooler 14 and the second valve element 62 on the side of the bypass tube 15 of the double plate valve 53 of the exhaust gas flow rate ratio control valve 18 according to the operating state of the engine 1 to suitable valve opening degrees possible to simultaneously reduce the output amount of NOx and the output amount of PM by changing the temperature of the EGR gas so that the EGR gas adopts the optimal temperature.

(Beneficial effect of the first embodiment)

As explained above, in the exhaust gas flow rate ratio control valve 18 this embodiment when the operation of the engine 1 is stopped by stopping the energization of the electromagnetic or electrically operated vacuum control valve 18a the introduction of the vacuum into the interior of the vacuum chamber 65a stopped and therefore the pressure difference between the pressure chamber 65 and the vacuum chamber 65a small. Accordingly, the membrane 64 and the valve stem 54 by the biasing force of the spring 55 moves downward and therefore the second valve element is at rest 62 on the side of the bypass tube 15 of the double plate valve 53 on the second valve seat on the (in the drawing) upper end side of the valve seat 56 , Accordingly, the first valve element opens 61 on the side of the EGR gas cooler 14 of the exhaust gas flow rate ratio control valve 18 the first opening 51 completely, and the second valve element 62 on the side of the bypass tube 15 of the exhaust gas flow rate ratio control valve 18 closes the second opening 52 Completely. Ie if the engine 1 is stopped, the first discharge opening 51 which the exhaust gas from the first exhaust gas channels 31 inside the EGR gas cooler 14 into the exhaust gas recirculation channel 43 initiates on the suction side, released (fully open), and the second inlet opening 52 which the exhaust gas from the second exhaust duct 32 inside the bypass tube 15 into the exhaust gas recirculation channel 43 initiates on the suction side, is blocked (completely closed).

This is generally related to the EGR gas passing through the exhaust pipes 22 (first exhaust channels 31 ) of the EGR gas cooler 14 flows when the EGR gas flows through the engine cooling water, which is inside the cooling water channel 23 of the housing 21 is circulated, cooled, the adhesiveness of the minute particles contained in the EGR gas is increased. To achieve an exhaust gas recirculation device of a type in which the first valve element 61 on the side of the EGR gas cooler 14 of the exhaust gas flow rate ratio control valve 18 resting on the first seat of the valve seat, there are tiny particles adhering to the surface of the first valve element 61 adhere and form a deposit, a possibility that the adhesive deposit the first valve element 61 and the first Ven tilsitz bridges and therefore stratifies an adhesive deposit. In such a case, the first valve element 61 fixed to the first valve seat the next time the engine was started, and therefore there is a possibility that the control responsiveness of the valve opening degree of the double-poppet valve 53 of the exhaust gas flow rate ratio control valve 18 , in particular the degree of valve opening of the first valve element 61 on the side of the EGR gas cooler 14 is deteriorated.

However, in the case of this embodiment, there is only opening of the first valve element 61 on the side of the EGR gas cooler 14 of the double plate valve 53 of the exhaust gas flow rate ratio control valve 18 when the engine 1 is stopped even if the minute particles contained in the gas on a surface of the first valve element 61 on the side of the EGR gas cooler 14 and the circumference of the first introduction opening 51 adhere and form an adhesive deposit, no possibility that the adhesive deposit layered in a state that the adhesive deposit over the first valve element 61 on the side of the EGR gas cooler 14 of the exhaust gas flow rate ratio control valve 18 and the valve housing (first valve seat 17 ) strokes, thereby fixing the first valve element 61 on the side of the EGR gas cooler 14 of the exhaust gas flow rate ratio control valve 18 can be prevented. Accordingly, it is possible to open / close the double poppet valve 53 of the exhaust gas flow rate ratio control valve 18 , in particular the first valve element 61 on the side of the EGR gas cooler 14 using that from, for example, the membrane 64 and the like formed vacuum actuator quietly, thereby the control response sensitivity of the valve opening degree of the double-plate valve 53 of the exhaust gas flow rate ratio control valve 18 , in particular the control response sensitivity of the valve opening of the first valve element 61 on the side of the EGR gas cooler 14 can be increased.

Here, as described above, it is necessary in a cold season for a period from starting to idling, the temperature of the EGR gas coming from the EGR module 7 flows out and into the interior of the intake duct 3 inside the exhaust gas recirculation duct 4 of the intake-side exhaust gas recirculation flow pipe 6 advances to the target EGR gas temperature (for example, about 130 ° C to 300 ° C), which corresponds to the operating state of the engine 1 (e.g. engine load) is set to control. Accordingly, in this embodiment, by arranging the double poppet valve 53 of the exhaust gas flow rate ratio control valve 18 near the downstream side of the exhaust gas cooler, which comes from the EGR gas cooler 14 , the bypass tube 15 and the like is constructed upon changing the temperature of the exhaust gas entering the inside of the intake pipe 3 inside the exhaust gas recirculation duct 4 flows further, the control response sensitivity of the valve opening degree of the double-plate valve 53 of the exhaust gas flow rate ratio control valve 18 increased by a measure corresponding to the volume (length) of the exhaust gas cooling device.

Furthermore, by performing the feedback control of the valve opening degree of the double-poppet valve 53 of the exhaust gas flow rate ratio control valve 18 based on the temperature deviation between the exhaust gas temperature and the target EGR gas temperature such that the temperature of the exhaust gas leading to the interior of the intake duct 3 inside the exhaust gas recirculation duct 4 continues to flow, matches the target EGR gas temperature, no possibility that the temperature of the exhaust gas leading to the interior of the intake duct 3 inside the exhaust gas recirculation duct 4 continues to flow, becomes abnormally low below the target EGR gas temperature (undershoot). Accordingly, the combustion state (engine combustion) inside the combustion chambers of the respective cylinders of the engine 1 cheaper, and therefore the speed of the engine 1 stabilized. Furthermore, by performing the feedback control of the valve opening degree of the double-poppet valve 53 of the exhaust gas flow rate ratio control valve 18 based on the temperature deviation between the exhaust gas temperature and the EGR gas temperature such that the temperature of the exhaust gas is further to the interior of the intake duct 3 inside the exhaust gas recirculation duct 4 flows with the target EGR gas temperature, there is no possibility that the temperature of the exhaust gas, which continues to the interior of the intake duct 3 inside the exhaust gas recirculation duct 4 flows, becomes abnormally high above the target EGR gas temperature (exceeded). Accordingly, there is no possibility that the EGR gas recirculation flow rate (EGR amount) or the EGR ratio, which is a ratio of the EGR amount with respect to the intake fresh air amount, becomes insufficient, and therefore the deterioration of the emission of the engine can 1 be suppressed.

That is, by executing the feedback control of the valve opening degree of the double-plate valve 53 of the exhaust gas flow rate ratio control valve 18 based on the temperature deviation between the temperature of the exhaust gas, which further to the interior of the intake duct 3 inside the exhaust gas recirculation duct 4 flows, and the target EGR gas temperature, there is no way that the temperature of the exhaust gas, which is further to the interior of the intake duct 3 inside the exhaust gas recirculation duct 4 flows, abnormally exceeds or falls below the target EGR gas temperature, making it possible to control the sophisticated control Generation of the temperature of the exhaust gas, which continues to the interior of the intake duct 3 inside the exhaust gas recirculation duct 4 flows so that the exhaust gas temperature quickly converges to the target EGR gas temperature. Accordingly, it is considering the improvement in the control responsiveness of the valve opening degree of the double-poppet valve 53 of the exhaust gas flow rate ratio control valve 18 extremely advantageous, the double plate valve 53 of the exhaust gas flow rate ratio control valve 18 near the downstream side of the exhaust gas cooling device, which consists of the EGR gas cooler, the bypass pipe 15 and the like is arranged to be arranged.

Further, in the exhaust gas recirculation device of this embodiment, there are between the exhaust gas recirculation flow pipe 5 , which branches from the exhaust pipe, and the intake-side exhaust gas recirculation flow pipe 6 , which unites with the exhaust pipe, and also between the cooling water pipe 8th and the cooling water pipe 9 of the engine cooling water circuit the EGR module 7 with the exhaust gas cooling device which comes from the two-way connection section 13 , the EGR gas cooler 14 , the bypass tube 15 , the connecting section 16 and the like is constructed, and with the valve housing 17 which the respective components of the exhaust gas flow rate ratio control valve 18 , the respective components of the exhaust gas recirculation flow rate control valve 19 and the respective components of the EGR flow sensor 20 holds, connected directly in series. With such a construction, the exhaust gas recirculation flow pipe, which is the EGR gas cooler 14 , the bypass tube 15 and the exhaust gas flow rate ratio control valve 18 connects the exhaust gas recirculation flow pipe which connects the exhaust gas flow rate ratio control valve 18 and the exhaust gas recirculation flow rate control valve 19 connects the cooling water pipe, which connects the EGR gas cooler 14 and the exhaust gas flow rate ratio control valve 18 connects, and the cooling water pipe, which is the exhaust gas flow rate ratio control valve 18 and the exhaust gas recirculation flow rate control valve 19 connects, not necessary and therefore the number of parts can be reduced. Accordingly, the assembly property of the EGR gas cooler 14 , the bypass tube 15 and the exhaust gas flow rate ratio control valve 18 as well as the mounting property of the exhaust gas flow rate ratio control valve 18 and the exhaust gas recirculation flow rate control valve 19 be improved. Furthermore, the channel lengths of the exhaust gas recirculation channel 4 and the cooling water channel can be extremely shortened, and therefore the construction of the pipeline can be simplified and the mountability of the exhaust gas recirculation device to a vehicle is further improved.

Furthermore, in this embodiment is in the middle of the exhaust gas recirculation channel 4 the exhaust gas cooling device configured so that the EGR gas cooler 14 and the bypass tube 15 are arranged parallel and close to each other. Accordingly, compared to the prior art in which the EGR gas cooler 14 and the bypass tube 15 are arranged away from each other, the structure of the exhaust gas cooling device can be reduced. Accordingly, the construction of the pipeline is simplified and the assembly of the exhaust gas cooling device is simplified, which can be improved by being able to mount the exhaust gas cooling device on a vehicle.

Furthermore, in this embodiment, by holding the respective components of the exhaust gas flow rate ratio control valve 18 and the respective components of the exhaust gas recirculation flow rate control valve 19 in the one valve housing 17 , ie by using these two valves 18 . 19 the one valve housing 17 share, the exhaust gas flow rate ratio control valve 18 and the exhaust gas recirculation flow rate control valve 19 be integrally formed in series. In this regard, the exhaust gas flow rate ratio control valve is in the prior art 18 and the exhaust gas recirculation flow rate control valve 19 with each other through the exhaust gas recirculation flow pipe between these two valves 18 . 19 connected, and therefore the exhaust gas recirculation flow pipe is in the outside air, which has been a disadvantage that the temperature fluctuations of the EGR gas have occurred. According to this embodiment, the above-mentioned structure enables the engine cooling water into the interior of the cooling water channel 27 of the valve housing 17 to flow, and therefore the temperature of the EGR gas passing through the interior of the exhaust gas recirculation channel 4 in the housing 17 flows, can be stabilized, and at the same time it is possible to reduce the temperature fluctuations of the EGR gas by shortening the duct length of the exhaust gas recirculation duct 4 to suppress.

Furthermore, a portion of the valve housing 17 which the exhaust gas recirculation channel between the exhaust gas flow rate ratio control valve 18 and the exhaust gas recirculation flow rate control valve 19 surrounds both the heat of the EGR gas, its temperature after passing through the EGR gas cooler 14 is made low, as well as the heat of the EGR gas, which after passing through the bypass pipe 15 maintains the high temperature, efficiently transmitted. Accordingly, the temperature of the valve body 17 , which has increased by absorbing the heat of the EGR gas, close to the temperature of the EGR gas, and therefore the temperature of the EGR gas, which is inside the exhaust gas recirculation duct of the valve housing 17 flows, stable.

Furthermore, since the channel length of the exhaust gas recirculation channel 4 is shortened, it is possible to measure the accuracy of an exhaust gas temperature sensor 104 to increase the temperature of the EGR gas after mixing the EGR gas which is inside the respective first exhaust gas channels 31 of the EGR gas cooler 14 flows, and the EGR gas, which is inside the second exhaust duct 32 of the bypass tube 15 flows, captured. Accordingly, it is possible to control the responsiveness of the valve opening degree of the double poppet valve 53 of the exhaust gas flow rate ratio control valve 18 and the control responsiveness of the valve opening degree of the valve 71 of the exhaust gas recirculation flow rate control valve 19 to increase.

Also use the exhaust gas flow rate ratio control valve 18 and the exhaust gas recirculation flow rate control valve 19 the one valve housing 17 with the cooling water channel 27 common, and therefore it is possible to use the in the exhaust gas flow rate ratio control valve 18 formed cooling water channel and in the exhaust gas recirculation flow rate control valve 19 trained trained cooling water channel integrally. With such a structure, the cooling water pipe, which is the in the exhaust gas flow rate ratio control valve 18 formed cooling water channel and in the exhaust gas recirculation flow rate control valve 19 Trained cooling water channel connects, unnecessarily and therefore there is no possibility that the temperature of the engine cooling water due to the heat exchange between the engine cooling water, which through the cooling water pipe between these valves 18 . 19 flows, and the outside air becomes unstable. Accordingly, the temperature of the EGR gas, which is inside the exhaust gas recirculation channel of the valve housing 17 flows, are stabilized, and therefore it is possible to control the sensitivity of the valve opening degree of the double-poppet valve 53 of the exhaust gas flow rate ratio control valve 18 and the control responsiveness of the valve opening degree of the valve 71 of the exhaust gas recirculation flow rate control valve 19 to increase.

Furthermore, in this exemplary embodiment, the exhaust gas cooling device is, in particular, by directly connecting the EGR gas cooler 14 and the exhaust gas flow rate ratio control valve 18 in series by means of the connecting section 16 integrally formed. In the prior art, the EGR gas cooler is connected 14 and the exhaust gas flow rate ratio control valve 18 by means of the exhaust gas recirculation flow pipe, a disadvantage that the heat transfer performance between these components is poor. Ie with regard to the internal components (e.g. bearings 57 ) of the exhaust gas flow rate ratio control valve 18 the heat of the EGR gas is applied to the internal components of the exhaust gas flow rate ratio control valve 18 by means of the valve housing 17 transferred when mixing. In this embodiment, by integrally forming the EGR gas cooler 14 and the exhaust gas flow rate ratio control valve 18 the heat of the low temperature EGR gas cooled by the engine cooling water also from the connection portion 16 directly on the valve housing 17 transmitted, and therefore it is possible the valve body 17 , which is caused by the heat of the EGR gas at high temperature, which comes directly from the bypass pipe 15 flowed, is heated to a high temperature, efficiently cool. In this way, by integrally forming the EGR gas cooler 14 and the exhaust gas flow rate ratio control valve 18 improves the heat transfer performance, and therefore it is possible to control the internal components of the exhaust gas flow rate ratio valve 18 to cool efficiently.

Furthermore, in this embodiment is in the valve housing 17 which the internal components (e.g. bearings 57 ) of the exhaust gas flow rate ratio control valve 18 and the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 picks up and holds, the cooling water channel 27 , in which the engine cooling water from the cooling water channel 23 of the EGR gas cooler 14 by means of the cooling water channel 26 flows on the side of the internal components (for example bearings 57 ) of the exhaust gas flow rate ratio control valve 18 and on the side of the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 regarding the exhaust gas recirculation duct 4 educated. Furthermore, the EGR gas cooler 14 regarding the bypass tube 15 on the side of the internal components (e.g. bearings 57 ) of the exhaust gas flow rate ratio control valve 18 and on the side of the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 arranged. With such a structure, it is by cooling the valve housing 17 using the engine cooling water coming from the cooling water channel 23 of the EGR gas cooler 14 through the cooling water channel 26 directly into the interior of the cooling water channel 27 is initiated, possible, the internal components (for example, bearings 57 ) of the exhaust gas flow rate ratio control valve 18 and the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 to cool efficiently.

Also uses the exhaust gas flow rate ratio control valve 18 this embodiment, the normally open valve as the first valve element 61 on the side of the EGR gas cooler 14 and uses the normally closed valve as a second valve element 62 on the side of the bypass tube. Accordingly, when the exhaust gas flow rate ratio control valve 18 fails, that is, when the valve element drive means of the Exhaust gas flow rate ratio control valve 18 becomes uncontrollable and therefore the valve closure becomes abnormal (for example, the double-plate valve 53 and the valve stem 54 of the exhaust gas flow rate ratio control valve 18 fixed in a non-raised state) while the second valve element 62 of the double plate valve 53 on the side of the bypass tube 1 is closed, the first valve element 61 of the double plate valve 53 on the side of the EGR gas cooler 14 opened with a predetermined valve opening degree. Even if the exhaust gas flow rate ratio control valve 18 fails, accordingly, the low-temperature exhaust gas flows through the EGR gas cooler 14 is cooled, into the interior of the exhaust gas recirculation duct of the valve housing 17 of the exhaust gas flow rate ratio control valve 18 and the exhaust gas recirculation flow rate control valve 19 , Accordingly, it is possible to use the internal components (e.g. bearings 57 ) of the exhaust gas flow rate ratio control valve 18 and the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 to protect against heat from the high-temperature exhaust gas.

Furthermore, when the exhaust gas flow rate ratio control valve 18 fails, that is, when the valve element driving device of the exhaust gas flow rate ratio control valve 18 becomes uncontrollable and therefore the valve opening becomes abnormal (for example, the double-plate valve 53 and the valve stem 54 of the exhaust gas flow rate ratio control valve 18 fixed in a raised state), both the first valve element 61 on the side of the EGR gas cooler 14 as well as the second valve element 62 on the side of the bypass tube 15 of the double plate valve 53 open. Even if the exhaust gas flow rate ratio control valve 18 accordingly, the low-temperature exhaust gas, which is caused by passing through the EGR gas cooler, fails 14 is cooled in the high-temperature exhaust gas, which is through the bypass pipe 15 flows, mixes and cools the high-temperature exhaust gas. Accordingly, it is possible to use the internal components (e.g. bearings 57 ) of the exhaust gas flow rate ratio control valve 18 and the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 to protect against heat from the high-temperature exhaust gas.

Furthermore, the exhaust gas flow rate ratio control valve 18 of this embodiment such that when the second valve element 62 on the side of the bypass tube 15 the second opening 52 , into which the exhaust gas from the second exhaust duct 32 inside the bypass tube 15 is initiated, fully opens the first valve element 61 on the side of the EGR gas cooler 14 the first opening 51 , into which the exhaust gas from the first exhaust duct 31 inside the EGR gas cooler 14 is initiated, opens with a predetermined degree of opening or more. That is, even if the high-temperature exhaust gas from the second exhaust duct 32 inside the bypass tube 15 through the second inlet opening 52 is initiated, it is by applying the construction that the first introduction opening 51 does not completely close with the use of the low temperature exhaust gas coming from the first exhaust duct 31 inside the EGR gas cooler 14 through the first opening 51 is initiated, possible, the internal components (for example, bearings 57 ) of the exhaust gas flow rate ratio control valve 18 and the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 to cool.

Accordingly, it is possible to use the internal components (e.g. bearings 57 ) of the exhaust gas flow rate ratio control valve 18 and the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 protect from heat of the high temperature exhaust gas, and therefore the occurrence of a displacement error of the valve stem 54 of the exhaust gas flow rate ratio control valve 18 and a misalignment of the valve stem 72 of the valve 71 of the exhaust gas recirculation flow rate control valve 19 can be prevented, which increases the control response sensitivity of the valve opening degree of the double-plate valve 53 of the exhaust gas flow rate ratio control valve 18 and the control responsiveness of the valve opening degree of the valve 71 of the exhaust gas recirculation flow rate control valve 19 can be increased.

Also on the housing 21 which is an outer shell of the EGR gas cooler 14 forms, several reinforcing ribs 24 formed at a uniform distance in such a state that the reinforcing ribs 24 protrude outwards. With such a structure, the plurality of reinforcing ribs are in the inner wall side 24 Recess sections, which the vortex flow in the engine cooling water, which by the inside of the EGR gas cooler 14 trained cooling water channel 23 flows, generate, trained. Accordingly, inside the cooling water channel 23 hardly any dwell portions of the engine cooling water are formed, and therefore, it is possible to prevent a phenomenon that the engine cooling water absorbs heat of the EGR gas at the dwell portions and the temperature of the engine cooling water excessively rises to a high temperature (boiling). That is, it is possible to reduce the cooling capacity of the EGR gas which passes through the inside of the first exhaust duct 31 of the EGR gas cooler 14 flows, prevent, and at the same time it is possible to prevent the excessive increase in pressure inside the housing 21 of the EGR gas cooler 14 to prevent, whereby the exhaust gas cooling device can be provided with the excellent durability.

Furthermore, in this embodiment, the bellows-like bellows section 36 which is in the cylinder direction of the bypass tube 15 is stretchable and shrinkable, integral with the bypass tube 15 educated. Such a construction can make the difference in thermal expansion between the EGR gas cooler 14 , which forms a low-temperature section by cooling the high-temperature exhaust gas with the engine cooling water, and the bypass pipe 15 which forms a high-temperature section by flowing through the high-temperature exhaust gas through the bellows section 36 can be accommodated, and therefore the exhaust gas cooling device can be provided with the excellent durability.

(Second embodiment)

4A and 4B show the second embodiment of the present invention and particularly show the essential structure of the EGR module, which is integrally formed from the exhaust gas cooling device, the exhaust gas flow rate ratio control valve and the exhaust gas recirculation flow rate control valve.

In this embodiment, by providing spiral heat transfer fins 29 inside the cooling water inlet section 28 , which at a (in the drawing) left end portion of the inside of the valve housing 17 trained cooling water channel 27 is formed, the heat of the valve housing 17 , the temperature of which is caused by an exhaust gas passing through the interior of the valve housing 17 flows, has risen to a high temperature, by means of the engine cooling water, which is inside the cooling water duct 27 circulated, cooled efficiently. With such a structure, the heat transfer performance (heat radiation performance) of the engine cooling water is further improved, and therefore it is possible to use the internal components (e.g. bearings 57 ) of the exhaust gas flow rate ratio control valve 18 and the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 to cool efficiently by means of the engine cooling water.

Accordingly, it is possible to use the internal components (e.g. bearings 57 ) of the exhaust gas flow rate ratio control valve 18 and the internal components (e.g. bearings 76 ) of the exhaust gas recirculation flow rate control valve 19 protect from heat of the high temperature exhaust gas, and therefore the occurrence of a displacement error of the valve stem 54 of the exhaust gas flow rate ratio control valve 18 and a misalignment of the valve stem 72 of the valve 71 of the exhaust gas recirculation flow rate control valve 19 can be prevented, which increases the control response sensitivity of the valve opening degree of the double-plate valve 53 of the exhaust gas flow rate ratio control valve 18 and the control responsiveness of the valve opening degree of the valve 71 of the exhaust gas recirculation flow rate control valve 19 increase.

(Modification)

In the above embodiments, the valve element driving device is the exhaust gas flow rate ratio control valve 18 from the actuator that can be operated with negative pressure with the electromagnetic or electrically operated negative pressure control valve 18a built up. However, the valve element driving device of the exhaust gas flow rate ratio control valve can 18 can also be constructed from an electrically operated actuator with a power unit, which contains a drive motor and a power transmission mechanism (for example a reduction mechanism or the like), or an electromagnetic actuator, such as an electromagnetic flow rate control valve. Further, in this embodiment, the valve element driving device is the exhaust gas recirculation flow rate control valve 19 composed of an electrically operated actuator with the power unit, which contains the drive motor and the power transmission mechanism (the reduction gear mechanism in this embodiment). However, the valve element driving device of the exhaust gas recirculation flow rate control valve 19 can also be constructed from an actuator that can be operated with negative pressure, with an electromagnetic or electrically operated control valve that can be operated with negative pressure, or an electromagnetic actuator such as, for example, an electromagnetic flow rate control valve.

In this embodiment, the valve body is the exhaust gas flow rate ratio control valve 18 directly with the downstream side of the exhaust gas cooler (the EGR gas cooler 14 and the bypass tube 15 ) connected in series, and at the same time is the valve housing of the exhaust gas recirculation flow rate control valve 19 directly with the downstream side of the exhaust gas flow rate ratio control valve 18 connected in series so that the one valve body 17 together through the exhaust gas flow rate ratio control valve 18 and the exhaust gas recirculation flow rate control valve 19 is used. However, it may be possible that only the valve body of the exhaust gas recirculation flow rate control valve 19 directly with the downstream side of the EGR gas cooler 14 is connected in series. Also in this case, the exhaust gas recirculation flow pipe and the cooling water pipe, which are the EGR gas cooler 14 and the exhaust gas recirculation flow rate control valve 19 connect, unnecessary and therefore the number of parts can be reduced. Furthermore, the assembly property of the EGR gas cooler 14 and the EGR flow rate th control valve 19 be improved. In addition, since the duct length of the exhaust gas recirculation duct and the cooling water duct can be extremely shortened, the construction of the pipeline is simplified and the mountability of the exhaust gas cooling device on a vehicle can be improved.

Here, it may be possible to use the exhaust gas recirculation flow pipe and the cooling water pipe, which are the EGR gas cooler 14 or the bypass tube 15 with the exhaust gas flow rate ratio control valve 18 connect, compared to the prior art by arranging the valve housing of the exhaust gas flow rate ratio control valve 18 near the downstream side of the EGR gas cooler 14 or the bypass tube 15 To shorten. Furthermore, it may also be possible to use the exhaust gas recirculation flow pipe and the cooling water pipe, which are the exhaust gas flow rate ratio control valve 18 and the exhaust gas recirculation flow rate control valve 19 connect, compared to the prior art by arranging the valve housing of the exhaust gas recirculation flow rate control valve 19 near the downstream side of the exhaust gas flow rate ratio control valve 18 To shorten.

In this embodiment, the valve (the valve element) is the exhaust gas flow rate ratio control valve 18 from the double plate valve 53 , which defines the opening areas of the first and second introduction openings 51 . 52 and the valve stem 54 , which is in the axial direction together with the double-poppet valve 53 The double plate valve moves back and forth, is set up and on 53 from the normally open first valve element 61 , which is the opening area of the first introduction opening 51 regulates, and the normally closed second valve element 62 , which is the opening area of the second introduction opening 52 regulates, builds up. However, the valve (the valve element) of the exhaust gas flow rate ratio control valve 18 can also be constructed from a normally open valve element (for example a poppet valve) which covers the opening area of only the first inlet opening 51 on the side of the EGR gas cooler (the exhaust gas heat exchanger valve) 14 regulates. Furthermore, it may be possible to reduce the number of parts or the number of hours worked and thus the costs by adding the valve element and the valve stem 54 of the double plate valve 53 or the poppet valve are integrally formed.

(Third embodiment)

5 is a schematic diagram for explaining the overall structure of an EGR system 200 , in which an EGR cooling device 2 is applied according to the first embodiment of the present invention.

6 is a cross-sectional view of an EGR cooler 203 in the EGR cooler 2 according to the first embodiment of the present invention.

7 Fig. 10 is a cross sectional view taken along a line VII-VII in Fig 2 ,

In the EGR system 200 stand as in 5 shown an exhaust duct 204 and an intake duct 205 of an engine 201 with each other through an EGR channel 206 connected to so part of an exhaust gas from the engine 201 to the intake duct 205 recirculate. That is, part of the engine exhaust is drawn into a cylinder of the engine. Then the EGR system controls 200 mainly a valve opening degree of a shuttle valve 233 , which will be described later, such that the exhaust gas that leads to the intake passage 205 is returned, that is, the EGR gas flow rate corresponding to an operating condition (speed, load or the like) of the engine 201 becomes an optimal flow rate. Usually the EGR channel 206 to the intake duct 205 on a downstream side of an air filter 211 opened and connected to it.

An EGR cooler 202 is like in 5 shown for cooling an EGR gas by means of an EGR cooler 203 which is in the middle of the EGR channel 206 is formed, thereby reducing the temperature of the EGR gas to the intake duct 205 is returned, is degraded.

The EGR cooler 202 is from the EGR cooler 203 which is in the middle of the EGR channel 206 is provided and the EGR gas cools by means of engine cooling water, a cooling water inlet pipe 206 which the cooling water from the cooling water channel 212 of the motor 201 to the EGR cooler 205 initiates, and a cooling water change valve 209 which is in the middle of the cooling water inlet pipe 208 is provided and the connection / interruption of the cooling water inlet pipe 208 changes, built. Here, the EGR cooler contains 203 a main channel 231 , which forms a first channel through which the EGR gas flows, a bypass channel 232 which has a second channel parallel to the main channel 231 forms and through which the EGR gas flows, a shuttle valve 233 , which is a first shuttle valve for changing the connection / disconnection of the main channel 231 forms, and a shuttle valve 234 , which has a second shuttle valve for changing the connection / interruption of the bypass channel 232 forms.

In a cooling water circuit of the engine 201 circulates the cooling water, which by a water pump 214 is pressurized as by egg an arrow in 5 indicated, inside the engine 201 and then flows over the cooling water channel 212 into a cooler 213 and is cooled. Then the cooling water through the cooling water channel 221 into the water pump 214 sucked and put under pressure and back to the engine 201 fed.

On the other hand, as in 5 shown a cooling water inlet 203c of the EGR cooler 203 with the cooling water channel 212 of the motor 201 via a cooling water inlet duct 208a connected while a cooling water outlet 203d of the EGR cooler 203 with the cooling water channel 221 of the motor 201 via a cooling water outflow channel 208b communicates. With such a structure, part of the cooling water which comes from the engine 201 in the cooler 213 flows through the cooling water inlet channel 208a the EGR cooler 203 , flows through the cooling water outflow channel 208b through a water jacket 235 , unites through the cooling water outflow channel 208b with the cooling water channel 221 , and gets into the water pump 214 sucked.

Furthermore, in the middle of the cooling water inlet channel 208a , as in 5 shown, a cooling water exchange valve 209 assembled. The cooling water change valve 209 contains an electromagnetically operated valve and is electrically controlled. The cooling water change valve 209 controls the introduction / interruption of the cooling water to the EGR cooler 203 by changing the connection / interrupting the cooling water inlet pipe 208 ,

Next is the construction of the EGR cooler 203 the EGR cooler 202 according to the third embodiment of the present invention.

The main part 239 of the EGR cooler 203 is made of a material which exhibits excellent heat resistance and erosion resistance, such as stainless steel or the like. At one end of the main part 239 of the EGR cooler 203 (left side in 2 ) is like in 6 shown a gas inlet 203a provided while on the other side of the main part 239 (right side in 6 ) a gas outlet 203b is provided. Accordingly, the EGR gas flows as in an arrow in 6 represented by the gas inlet 203a in the EGR cooler 203 and flows through the gas outlet 203b from the EGR cooler 203 out.

As in 6 shown, contains the EGR cooler 203 as a channel through which the EGR gas flows, a main channel 231 and one parallel to the main channel 231 arranged bypass channel 232 , The EGR gas flows through the interior of the main channel 231 and the inside of the bypass channel 232 in the by an arrow in 6 shown direction. The main channel 231 and the bypass channel 232 are made of stainless steel and are formed in a tube shape and the cross-sectional shapes of the two channels 231 . 232 in the direction perpendicular to the flow direction (left / right direction in 6 ) of the EGR gas are the same as in 7 shown. Furthermore are in the main channel 231 , as in 7 shown, inner ribs 231 attached. These inner ribs 231 increase an amount of heat radiation from the EGR gas to the cooling water in the main duct 231 , Here, the EGR cooler contains the EGR cooler 202 according to the third embodiment of the present invention, six main channels 231 and three bypass channels 232 , At both ends of each of the main channels 231 and the bypass channels 232 are end plates 236a . 236b tightly assembled by soldering, welding or the like.

Ie a space through a body section 239 , Outer circumference of both channels 231 . 232 and the end plates 236a and 236b surrounded, defines a water jacket 235 through which the cooling water flows. On the body section 239 are according to the water jacket 235 , as in 6 shown a cooling water inlet 203c and a cooling water outlet 203d educated. By removing the cooling water from the cooling water inlet 203c inside the water jacket 235 pour and spread through the interior of the water jacket 235 to the cooling water outlet 203d The heat exchange between the EGR gas, which passes through the main channels 231 and the bypass channels 232 flows, and performed the cooling water. That is, the EGR gas is cooled by its heat exchange.

On a downstream side (right side in 6 ) on the downstream side (right side in 6 ) of the main channel 231 and the bypass channel 232 provided end plate 236b is like in 6 shown, a valve seat plate 238 attached. The valve seat plate 238 is made of a material which exhibits excellent heat resistance and wear resistance, such as alloy steel with nickel, molybdenum or the like. In the valve seat plates 238 are valve seat sections 238a . 238b trained on which shuttle valves 233 . 234 rest, which will be explained later.

Between the end plate 236b and the valve seat plate 238 is like in 6 shown a partition plate 237 intended. The partition plate 237 breaks the connection between the main channel 231 and the bypass channel 232 in one between the end plate 236b and the valve seat plate 238 defined space.

On the downstream side (right side) of the valve seat plate 238 are like in 6 shown, a shuttle valve 233 , which is a first shuttle valve for changing the connection / disconnection of the main channel 231 forms, and a shuttle valve 234 , which has a second shuttle valve for changing the connection / interruption of the bypass channel 232 forms, provided.

In the shuttle valves 233 . 234 For example, a stepper motor, a linear solenoid, or the like is used as an energy source. Ie the shuttle valves 233 . 234 are of a type which valve opening degrees, ie strokes of the valve element 233a and the valve element 234a (in the left / right direction in 6 positioned) can control continuously. In other words, the shuttle valves 233 . 234 designed so that the valve elements 233a . 234a not only can assume a fully closed position and a fully open position, but can also be held in any position between the fully closed position and the fully open position.

Accordingly, by controlling the degree of valve opening, it is one of the two shuttle valves 233 . 234 or by simultaneously controlling the valve opening degrees of both shuttle valves 233 . 234 through the controller 210 possible a flow rate of the EGR gas leading to the intake duct 205 is returned to control.

If the valve element 233a of the shuttle valve 233 on the valve seat section 238a the valve seat plate 238 is at rest, becomes the main channel 231 interrupted while when the valve element 233a a predetermined distance in the direction away from the valve seat portion 238a (right direction in 6 ) is moved and released, the main channel 231 assumes a connection state. Analog becomes when the valve element 234a of the shuttle valve 234 on the valve seat section 238b the valve seat plate 238 is at rest, the bypass channel 232 interrupted while when the valve element 234a a predetermined distance in the direction away from the valve seat portion 238b (right direction in 6 ) moves and assumes a released state, the bypass channel 232 assumes a connection state. Here shows 6 the shuttle valve 233 in a closed state and the shuttle valve 234 in a released state.

Next is how the EGR system works 200 in which the EGR cooler 202 with the above structure is applied, focusing on the operation of the EGR cooling device 202 in connection with the schematic representation in 1 explained.

In the EGR system 200 receives control 210 , as in 5 shown energy from a battery 220 through an ignition switch 219 , Then, according to the operating condition of the engine 201 , that is, according to the various sensors 215 . 216 . 217 . 219 the changeover valve 233 and the shuttle valve 234 driven and thus the cooling / non-cooling of the EGR gas, which is the intake duct 205 is returned, controlled and at the same time the flow rate of the EGR gas, which is the intake duct 205 is returned to an optimal value. Here, in the EGR system 200 according to the third exemplary embodiment of the present invention as sensors for detecting the operating state of the engine 201 a water temperature sensor 215 to detect the temperature of the cooling water, an exhaust gas temperature sensor 216 to record the exhaust gas temperature, a speed sensor 217 for detecting the speed of a crankshaft (not shown in the drawing) and a load sensor 218 used. Here can be used as a load sensor 218 for example a fuel injection quantity sensor (not shown in the drawing) of the engine 201 , a throttle valve sensor for detecting the rotational position of a throttle valve (not shown in the drawing) or the like can be used. It is possible to use a fuel injection quantity sensor (not shown in the drawing) of the engine 201 , a throttle valve sensor (not shown in the drawing), which detects the rotational position of the throttle valve, or the like as a load sensor 218 to use.

(1) The case in which the engine 201 is in a no-load range or in an extremely low load range and the exhaust gas temperature is equal to or lower than a predetermined value.

Here, the specified value of the exhaust gas temperature specifies a value that is lower than the exhaust gas temperature during normal operation of the engine 201 and appears immediately after starting the engine or when idling, with the predetermined value of the exhaust gas temperature being determined for each engine.

In this case the control system drives 21 1 the shuttle valve 233 in an interrupted state, the shuttle valve 234 in a connected state or the cooling water exchange valve 209 in an interrupted state. Furthermore, the valve opening degree of the shuttle valve 234 controlled so that the flow rate of the EGR gas entering the intake duct 205 is returned, assumes the optimal value.

With such a structure, the EGR gas is introduced into the intake passage through the bypass passage 232 of the EGR cooler 203 returned, and that Cooling water no longer flows into the EGR cooler 203 , Because the bypass channel 232 no inner ribs 231 and the cooling water is not in the EGR cooler 203 flows, a decrease in the temperature of the EGR gas in the EGR cooler becomes extremely small, making it possible to change the combustion state of the engine 201 to stabilize. Because the bypass channel 232 no inner ribs 231 furthermore, minute particle components in the EGR gas, especially components with strong adhesiveness, do not adhere to the bypass channel 232 and therefore there is no possibility that the tiny particle components in the EGR gas on the EGR cooler 203 cling or build up.

(2) The case in which the engine 201 is in the low load range or in the intermediate load range and the exhaust gas temperature exceeds a predetermined value.

In this case the control system drives 210 the shuttle valve 233 in a connected state, the shuttle valve 234 in an interrupted state or, the cooling water exchange valve 208 in a connection state. Furthermore, the valve opening degree of the shuttle valve 233 controlled so that the flow rate of the EGR gas leading to the intake duct 205 is returned, assumes the optimal value.

With such a structure, the EGR gas becomes the intake passage through the main passage 231 of the EGR cooler 203 returned, and the cooling water flows into the water jacket 235 of the EGR cooler 203 , The inner ribs 231 are on the main channel 231 provided and the cooling water flows into the EGR cooler 203 and therefore the EGR gas after passing through the EGR cooler 203 cooled, which lowers the EGR gas temperature. Accordingly, it is possible to achieve the favorable NOx reduction effect through the EGR system 200 to achieve.

(3) The case where the engine 201 is in a low load range or in an intermediate load range and the exhaust gas temperature exceeds a second predetermined value.

Here, the second predetermined value of the exhaust gas temperature indicates a value which is higher than the exhaust gas temperature during normal operation of the engine and appears when the load of the engine 201 is large or the like, the second predetermined value of the exhaust gas temperature being determined for each engine.

In this case the control system drives 210 the shuttle valve 233 in a connected state, the shuttle valve 234 in a connected state or the cooling water exchange valve 208 in a connection state. Furthermore, the valve opening degree of the shuttle valve 233 and the valve opening degree of the shuttle valve 234 controlled so that the flow rate of the EGR gas leading to the intake duct 205 is returned, assumes the optimal value.

With such a structure, the EGR gas becomes the intake passage through the main passage 231 and the bypass channel 232 of the EGR cooler 203 returned, and the cooling water flows into the water jacket 235 of the EGR cooler 203 , Rib inside 231 are on the main channel 231 provided and the cooling water flows into the EGR cooler 203 , and therefore the EGR gas after passing through the EGR cooler 203 cooled, which lowers the temperature of the EGR gas. Also in the bypass channel 232 Heat of the EGR gas is radiated to the cooling water from an outer surface thereof, and therefore the temperature of the EGR gas can be reduced. That is, while the bypass channel has no EGR gas cooling function in the conventional EGR cooling device, it is in the EGR cooling device 202 according to the third embodiment of the present invention, the EGR gas cooling function of the bypass channel 232 added. Accordingly, it is possible to achieve the favorable NOx reduction effect through the EGR system 200 to achieve.

The EGR cooler 202 according to the third embodiment of the present invention explained above has the following structure. Ie in the middle of the cooling water inlet channel 208 which is the cooling water in the EGR cooler 203 initiates, is the cooling water change valve 209 provided that the introduction and the interruption of the cooling water to the EGR cooler 203 on. The main channel also contains 231 through which the EGR gas flows, the bypass channel 232 which is parallel to the main channel 231 is arranged, the shuttle valve 233 which is the connection and disconnection of the main channel 231 changes, and the shuttle valve 234 which connects and disconnects the bypass channel 232 replaced.

In the conventional EGR cooler 202 the bypass duct and the duct change valve form parts which are separate from the EGR cooler. In this exemplary embodiment, however, the bypass channel and the channel change valve are integral as a bypass channel 232 and shuttle valves 233 . 234 formed, creating a single part inside the EGR cooler 203 is formed. Accordingly, in particular, the number of pipe connection sections relevant for the EGR gas can be greatly reduced and the working hours for assembling the EGR cooling device 202 in the engine 201 can be reduced.

Furthermore, if necessary, the introduction of the cooling water to the EGR cooler 203 by means of the cooling water change valve 209 to be interrupted. That is, immediately after the engine is started or when the engine operating state is in a low load range or the like, that is, when the EGR gas is not through the main passage 231 flows but through the bypass channel 232 flows, it is possible the cooling function of the EGR cooler 203 by interrupting the introduction of the cooling water into the EGR cooler 203 to stop. Accordingly, by suppressing the lowering of the temperature of the EGR gas passing through the bypass passage 232 flows to a minimum level the combustion immediately after starting the engine 201 or if the operating state of the engine 201 is in an extremely low load range.

Furthermore, the shuttle valves 233 . 234 can be controlled separately and therefore it is possible if the exhaust gas temperature of the engine 201 is higher, the EGR gas through both the main channel 231 as well as the bypass channel 232 to flow. Such a structure also in the bypass channel 232 Heat of the EGR gas is radiated into the cooling water, and therefore the EGR gas cooling can be realized. That is, in the conventional EGR gas cooling device, the EGR gas does not flow in the bypass passage when the EGR cooler is used. In contrast, this exemplary embodiment makes use of the bypass channel for EGR gas cooling. Accordingly, the bypass passage, which is used only for a short time such as during engine starting, that is, the bypass passage, which shows low operability in the conventional EGR gas cooling device, can be used for cooling the EGR gas in this embodiment, and therefore, the construction of the entire EGR cooling device can be reduced.

Furthermore, the main channel 231 and the bypass channel 232 formed by pipe members with the same cross-sectional shape in the direction perpendicular to the flow direction of the EGR gas. Accordingly, it is sufficient to provide a single type of mold for manufacturing the tubular members, and therefore the manufacturing cost of the EGR cooler can 203 be reduced. Furthermore, if necessary, the entire cross-sectional area of the main channel 231 and the entire cross-sectional area of the bypass channel 232 simply by changing the number of pipe elements.

Fourth Embodiment

8th is a schematic diagram for explaining the overall structure of the EGR system 200 in which the EGR cooler 202 according to the fourth embodiment of the present invention.

In the EGR system 200 in which the EGR cooler 202 is applied according to the fourth embodiment of the present invention, the structure of the EGR cooler 203 changed and the EGR valve 207 is added.

The EGR valve 207 is substantially the same as the EGR valve used in the conventional EGR cooling device. Ie the EGR valve 207 is designed to continuously control the flow rate of the EGR gas flowing through the intake port 205 is returned.

On the EGR cooler 203 are the shuttle valves 301 . 302 instead of the shuttle valves used in the first embodiment 233 . 234 assembled.

While the shuttle valves 233 . 234 apply the method in which the valve opening degree can be continuously controlled, use the shuttle valves 301 . 302 this embodiment, a method that the valves 301 . 302 drive only in the open position (fully closed) or in the connection position (fully open).

In the EGR system 200 in which the EGR cooler 202 applied according to the fourth embodiment of the present invention, control the shuttle valves 301 . 302 only the connection / interruption of the main channel 231 or the bypass channel 232 while controlling the EGR gas flow rate through the EGR valve 207 is carried out.

In continuously controlling the valve opening degree by means of the shuttle valve to increase the control accuracy of the EGR gas flow rate, it is necessary to provide some valve opening degree detection sensors, and these can increase the cost of the shuttle valve. In the second embodiment, the shuttle valve, which continuously controls the valve opening degree, is only from the EGR valve 207 built up, and therefore the increase in the cost of the EGR system 200 be suppressed.

This can be done in the EGR cooling device 202 according to the third and fourth embodiments of the present invention, which have been explained above, although the shuttle valves 233 . 234 . 301 . 302 use a mushroom-shaped type as the valve type, a valve of another valve type can also be used. For example, a wing valve, a sleeve valve or the like can be used as a shuttle valve 233 . 234 be used.

Furthermore, these embodiments are so far as an engine is of a type in which the EGR cooling device 201 of these embodiments is applicable to both the gasoline engine and the diesel engine.

Claims (24)

Exhaust gas recirculation device, with an exhaust gas recirculation channel ( 4 ) for returning a part of an exhaust gas in an internal combustion engine to an intake side; an exhaust gas recirculation flow rate control valve ( 19 ) for continuously or gradually controlling an overall flow rate of the exhaust gas flowing through the interior of the exhaust gas recirculation duct; an exhaust gas heat exchanger ( 14 ), which is in the middle of the exhaust gas recirculation 4 ) is provided and cools the exhaust gas which is inside the exhaust gas recirculation channel ( 4 ) flows; a bypass tube ( 15 ), which in the exhaust gas recirculation channel ( 4 ) is provided, the exhaust gas at the exhaust gas heat exchanger ( 14 ) flows past and through the bypass tube ( 15 ) flows; and an exhaust gas flow rate ratio control valve ( 18 ), which in the exhaust gas recirculation channel ( 4 ) is provided and a ratio between a flow rate of the inside of the exhaust gas heat exchanger ( 14 ) flowing exhaust gas and a flow rate of the exhaust gas which is inside the bypass tube ( 15 ) flows, continuously or stepwise, characterized in that the exhaust gas flow rate ratio control valve ( 18 ) near the downstream side of the exhaust gas heat exchanger ( 14 ) and the bypass tube ( 15 ) is arranged; that the exhaust gas flow rate ratio control valve ( 18 ) contains: a first inlet opening ( 41 ), which introduces the exhaust gas from the exhaust gas heat exchanger into the intake side, a second inlet opening ( 42 ), which introduces the exhaust gas from the bypass pipe into the intake side, and a valve ( 61 . 62 ) which adjusts at least one opening area of the first introduction opening; and that the valve ( 61 . 62 ) is configured around the first introduction opening ( 41 ) to open when the operation of the internal combustion engine is stopped. Exhaust gas recirculation device according to Claim 1, in which the valve consists of a normally open first valve element ( 61 ), which is the opening area of the first introduction opening ( 41 ) and a normally closed second valve element ( 62 ), which is the opening area of the second inlet opening ( 42 ) is set up, and the exhaust gas flow rate ratio control valve ( 18 ) is configured to the first valve element ( 61 ) the first opening ( 41 ) to open with a predetermined degree of opening or more if the second valve element ( 62 ) the second opening ( 42 ) open completely. An exhaust gas recirculation device according to claim 2, wherein the exhaust gas flow rate ratio control valve ( 18 ) is configured to the first valve element ( 61 ) to open and the second valve element ( 62 ) close when the operation of the internal combustion engine is stopped. Exhaust gas recirculation device according to claim 2 or 3, wherein the valve ( 61 . 62 ) is a double-plate valve which has a first flange section ( 61 ) with an approximately circular shape, which the first valve element ( 61 ) and a second flange section ( 62 ) with an approximately circular shape, which the second valve element ( 62 ) forms, as well as a shaft-like section ( 54 ), which together with the first flange section ( 61 ) and the second flange section ( 62 ), contains. Exhaust gas recirculation device according to one of Claims 2 to 4, in which the exhaust gas flow rate ratio control valve ( 18 ) an actuator ( 60 ), which is the first valve element ( 61 ) drives in the valve closing direction and the second valve element ( 62 ) drives in the valve opening direction, and a valve element biasing device ( 55 ) which the second valve element ( 61 ) in the valve opening direction and the second valve element ( 62 ) biased in the valve closing direction. Exhaust gas recirculation device according to one of Claims 1 to 5, in which the exhaust gas heat exchanger is an exhaust gas pipe ( 22 ) which contains a first exhaust duct ( 31 ) forms in the bypass tube ( 15 ) a second exhaust duct ( 32 ) to redirect the exhaust gas around the first exhaust gas duct ( 22 ) includes the exhaust gas flow rate ratio control valve ( 18 ) a mixing chamber ( 43 ) for mixing the high-temperature exhaust gas and the low-temperature exhaust gas, and the mixing chamber ( 43 ) with the first exhaust duct ( 31 ) through the first inlet opening ( 41 ) is connected and also with the second exhaust duct ( 32 ) through the second inlet opening ( 42 ) is connected. Exhaust gas recirculation device according to one of Claims 1 to 6, in which the exhaust gas flow rate ratio control valve ( 18 ) a connecting duct that connects to the exhaust gas heat exchanger ( 14 ) through the first inlet opening ( 41 ) is connected and also with the bypass tube ( 15 ) through the second inlet opening ( 42 ) is connected, a valve element which controls an opening area of the connecting channel, an actuator ( 66 ), which the valve element ( 61 . 62 ) in the valve opening direction drives and the valve element biasing device ( 55 ), which biases the valve element in the valve closing direction. Exhaust gas recirculation device according to one of Claims 1 to 7, in which an exhaust gas cooling device is designed such that the exhaust gas heat exchanger ( 14 ) and the bypass tube ( 15 ) are arranged parallel and close to each other in the exhaust gas recirculation channel. Exhaust gas recirculation device according to one of Claims 1 to 8, in which the bypass pipe ( 15 ) is designed to be essentially the same size as a cylinder direction size of the exhaust gas heat exchanger ( 14 ) and a bellows-like bellows section ( 37 ), which is in the cylinder direction of the bypass tube ( 15 ) is stretchable and retractable. Exhaust gas recirculation device according to one of claims 1 to 9, in which in the middle of the exhaust gas recirculation channel ( 4 ) the exhaust gas heat exchanger ( 14 ), the bypass tube ( 15 ) and the exhaust gas flow rate ratio control valve ( 18 ) are connected directly in series. Exhaust gas recirculation device according to one of claims 1 to 10, in which in the middle of the exhaust gas recirculation channel ( 4 ) the exhaust gas flow rate ratio control valve ( 18 ) and the exhaust gas recirculation flow rate control valve ( 19 ) are connected directly in series. Exhaust gas recirculation device according to one of Claims 1 to 1 1, in which internal components of the exhaust gas flow rate ratio control valve ( 18 ) and internal components of the exhaust gas recirculation flow rate control valve ( 19 ) inside a housing ( 17 ) are recorded and held. Exhaust gas recirculation device according to one of Claims 1 to 12, in which the exhaust gas recirculation device contains a cooling water circuit channel which stores the cooling water in the internal combustion engine in the order of the exhaust gas heat exchanger ( 14 ), the exhaust gas flow rate ratio control valve ( 18 ) and the exhaust gas recirculation flow rate control valve ( 19 ) circulates, and the exhaust gas heat exchanger ( 14 ), the exhaust gas flow rate ratio control valve ( 18 ) and the exhaust gas recirculation flow rate control valve ( 19 ) are directly connected in series in the middle of the cooling water circuit channel. Exhaust gas recirculation device according to claim 13, wherein a housing 17 that the internal components of the exhaust gas flow rate ratio control valve ( 18 ) and the internal components of the exhaust gas recirculation flow rate control valve ( 19 ) includes and holds, contains a cooling water passage which part of the cooling water circuit passage on a side of the inner components of the exhaust gas flow rate ratio control valve ( 18 ) and on one side of the internal components of the exhaust gas recirculation flow rate control valve ( 19 ) forms with respect to the exhaust gas recirculation channel, and the exhaust gas heat exchanger ( 14 ) regarding the bypass tube ( 15 ) on the side of the internal components of the exhaust gas flow rate ratio control valve ( 18 ) and on the side of the internal components of the exhaust gas recirculation flow rate control valve ( 19 ) is arranged. Exhaust gas recirculation device according to claim 13, wherein a housing 17 , the internal components of the exhaust gas flow rate ratio control valve ( 18 ) and internal components of the exhaust gas recirculation flow rate control valve ( 19 ) includes and holds, contains a cooling water passage which part of the cooling water circuit passage on a side of the inner components of the exhaust gas flow rate ratio control valve ( 18 ) and on one side of the internal components of the exhaust gas recirculation flow rate control valve ( 19 ) with respect to the exhaust gas recirculation channel, and heat transfer fins ( 29 ) for the effective transfer of heat from the cooling water circulating inside the cooling water channel to the housing ( 17 ) are provided inside the cooling water duct. Exhaust gas recirculation device according to one of Claims 2 to 15, in which the exhaust gas recirculation device comprises an operating state detection device ( 101 ), which detects an operating state of the internal combustion engine, an exhaust gas temperature detection device ( 104 ), which has an exhaust gas temperature inside the exhaust gas recirculation duct ( 4 ) and an engine control device that determines a valve opening degree of the exhaust gas flow rate ratio control valve ( 18 ) and a valve opening degree of the exhaust gas recirculation flow rate control valve ( 19 ) based on that by the operating state detection device ( 101 ) detected operating state of the internal combustion engine or that by the exhaust gas temperature detection device ( 104 ) controls the detected exhaust gas temperature. Exhaust gas recirculation device according to Claim 16, in which the operating state detection device ( 104 ) contains at least one cooling water temperature detection device which contains a temperature of the cooling water in the internal combustion engine ( 1 ), and the engine control device detects the valve opening degree of the exhaust gas flow rate ratio control valve ( 18 ) to open the second valve element ( 62 ) controls when the temperature of the cooling water in the internal combustion engine detected by the cooling water temperature detection device ( 1 ) is lower than a first predetermined value, and the valve opening degree of the exhaust gas flow rate ratio control valve ( 18 ) to open the first valve element ( 61 ) and to close the second valve element ( 62 ) controls when the temperature of the cooling water in the internal combustion engine detected by the cooling water temperature detection device ( 1 ) is higher than a second specified value. Exhaust gas recirculation device according to Claim 16 or 17, in which the operating state detection device ( 101 ) contains at least one engine load detection device which shows a load state of the internal combustion engine ( 1 ) is detected, and the engine control device provides feedback control of the valve opening degree of the exhaust gas flow rate ratio control valve ( 18 ) performed by the exhaust gas recirculation device ( 104 ) detected exhaust gas temperature essentially with a load state of the internal combustion engine determined by the engine load detection device ( 1 ) to set the setpoint. Exhaust gas recirculation device, with an EGR cooler ( 203 ), which is mounted in the middle of an EGR duct, which has an exhaust duct ( 204 ) and an intake duct ( 205 ) of an engine ( 1 ) connects and an EGR gas by flowing part of the cooling water into the engine through the inside of the EGR cooler ( 203 ) cools, and with a cooling water change valve ( 209 ) for switching the introduction and interruption of the cooling water into the EGR cooler ( 203 ), characterized in that the EGR cooler ( 203 ) contains: a first channel ( 231 ) in which the EGR gas flows; a second channel ( 232 ), which is parallel to the first channel ( 231 ) is provided and in which the EGR gas flows; a first shuttle valve ( 233 ), which connects and disconnects the first channel ( 231 ) switches; and a second shuttle valve ( 234 ), which connects and breaks the second channel ( 232 ) switches; and that when the cooling water is introduced into the EGR cooler ( 203 ) through the cooling water change valve ( 209 ) is interrupted, the second channel ( 232 ) through the second shuttle valve ( 234 ) is made connecting and the first channel ( 231 ) through the first shuttle valve ( 233 ) is interrupted. Exhaust gas recirculation device according to claim 19, wherein a valve opening degree of the first shuttle valve ( 233 ) is continuously controllable. Exhaust gas recirculation device according to claim 19, in which valve opening degrees of the first shuttle valve ( 233 ) and the second shuttle valve ( 234 ) are continuously controllable. Exhaust gas recirculation device according to claim 21, wherein the first channel ( 231 ) and the second channel ( 232 ) have formed a cross-sectional shape thereof in the direction perpendicular to the EGR gas flow direction from the same tubular member. Exhaust gas recirculation device according to one of Claims 19 to 21, in which the flow resistance of the first channel ( 231 ) greater than the flow resistance of the second flow channel ( 232 ) is. Exhaust gas recirculation device according to Claim 22 or 23, in which the first channel ( 232 ) forming tube element inner fins ( 231 ) to promote heat exchange inside it.